63586562 plastics-technology-handbook-volume-2

Plastics
TechnologY
Handbook
edited by
Donald V. Rosato
PhD, MBA, MS, BS, PE
Marlene G. Rosato
BASc (ChE), P Eng
Nick R. Schott
PhD, MS, BS (ChE), PE
UMASS Lowell Professor of Plastics Engineering Emeritus
& Plastics Department Head Retired
V O L U M E 2
Manufacturing • Composites • Tooling • Auxiliaries
ISBN: 978-1-60650-082-8
9 781606 500828
90000
Rosato
Rosato
Schott
VOLUME 2
Plastics
TechnologY
Handbook
MANUFACTURING • COMPOSITES
TOOLING • AUXILIARIES
www.momentumpress.net
This comprehensive two-volume handbook provides a simplified, practical, and
innovative approach to understanding the design and manufacture of plastic
products. It will expand the reader’s understanding of plastics technology by
defining and focusing on past, current, and future technical trends. In Volume
1, plastics behavior is presented so as to help readers fabricate products that
meet performance standards, low cost requirements, and profitability targets.
In this second volume, all major plastics compounding and forming technolo-
gies are presented—from mass production extrusion and injection processes to
specialty techniques like rotational molding, compression molding, spray mold-
ing, encapsulation, potting, ink screening, impregnation, and vacuum-assisted
liquid injection molding, among many others. A chapter on Coating provides all
the major forms of modifying surface properties of plastics for desired thermal,
physical and chemical behavior. A chapter on Casting focuses in all major meth-
ods of forming plastic melts in physical molds, including mold types, removal
molds and quality control issues. A unique chapter on Mold and Die Tooling
offers hard to find information on tool and die design specific to plastics manu-
facture--including detailed explanation on die design and use, tooling materials,
tool casting and machining, and a 41- page glossary of common die and tooling
terms. Finally, an extensive chapter on Auxiliary and Supplementary machines
and systems provides incredibly useful background—for everything from bond-
ing, chemical etching, cutting, and decorating to plastics machining, pelletiz-
ing, printing, polishing, stamping, vacuum debulking, welding, and many more
processes involved in bringing desired plastics products to market. This chapter
also extensively covers various means of mechanical assembly of plastics parts.
Over 15,000 subjects are reviewed with 1800 figures and 1400 tables. This
2,500 page, two-volume handbook will be of interest to a wide range of plas-
tics professionals: from plastics engineers to tool makers, fabricators, designers,
plant managers, materials suppliers, equipment suppliers, testing and quality
control personnel, and cost estimators. Moreover, this handbook provides an ex-
cellent introduction to students studying the plastics field.
Contents Synopsis: Preface, Coating, Casting, Reaction Injection Molding, Rota-
tional Molding, Compression Molding, Reinforced Plastic, Other Processes, Mold
and Die Tooling, Auxiliary and Secondary Equipment, Glossary, Further Reading.
Plastics TechnologY
Handbook
VOLUME 2: Manufacturing • Composites • Tooling • AuxiliarieS
Edited by Donald V. Rosato • Marlene G. Rosato • Nick R. Schott

Aboutthe Authors v
Figures xvii
Tables xxxi
Abbreviations xli
Acknowledgments xlix
Preface li
10. Coating 1
OVERVIEW 1
Different CoatingAspect 8
TERMAND PERFORMANCE INTRODUCTION 11
Paint 14
Water-Based Paint 16
Varnish 17
Lacquer 17
Solvent 17
PROPERTIES OF PLASTICS 21
Thermoplastic Coating 22
TS Coating 23
Contents
imo-rosato2.indb 7 7/27/11 12:12 PM

viii Contents
FUNDAMENTALS OF RESIN FORMATION 23
CondensationType 24
AdditionType 26
Fluorine-Containing Resin 35
Acrylic Resin 35
Cellulosic Resin 35
Copolymer Resin 36
Coumarone-lndene Resin 36
Parylene 36
APPLICATION 39
Coil Coating 40
Strippable Coating 44
Germ-Free Coating 45
EVALUATION METHOD 45
PROCESS 46
Overview 46
Film Solidification 55
Coating Methods 56
Coating Equipment 59
Roll-Coat Finish 59
Spread Coating 60
Floating Knife Coater 60
Fluidized Bed Coating 61
Spray Coating 61
Powder Coating 62
Electrostatic Spraying 62
Coil Coating (Metal Coating) 62
PROPERTY 63
Corrosion and Chemical Resistance 64
Fire Retardant 66
Intumescent Coating 67
Heat Resistant 68
Thermal Control 68
Electrical Insulating 69
SIMULATED SERVICETESTS 70
Abrasion Resistance 70
Adhesion 71
AcceleratedAging in HotAir 71
Accelerated aging in oxygen 72
Blocking 72

Contents ix
Burst Strength 72
Compression Set 72
Curl 72
Elongation 73
Flame Resistance,Vertical 73
Flexibility 73
Hardness 73
Hydrostatic Resistance 74
LowTemperature Cracking 74
Modulus 74
Gas Permeability 75
Liquid Permeability 75
pHValue 75
Resiliency 75
Stretch 75
Swelling 78
Tear Strength 78
Tensile Strength 79
Thickness 79
Wicking 79
Weathering 79
SOLVENTAND COATING 80
Solvent Composition in Coating 80
Solvent and Solvent-Free Coatings 83
Emission 84
CleanAirAct 87
SOLVENT SUBSTITUTION 87
11. Casting 90
INTRODUCTION 90
PLASTIC 91
PROCESSES 92
CASTING OFACRYLIC 96
Introduction 96
Casting Sheet 97
Casting Rod andTube 98
Embedment 99
Filled Casting 99
Prototype Casting 100
CASTING OF NYLON 100

x Contents
Introduction 100
Process 101
SOLVENT CASTING OF FILM 102
12. Reaction Injection Molding 103
INTRODUCTION 103
EQUIPMENT 108
MOLD 109
Runner and Gate Design 115
Cost 115
PROCESSING 120
Process Control 123
MATERIAL 124
Conversion Process 130
TP Polyurethane 133
TS Polyurethane 133
Cure ofTS 133
Polymerization 134
RRIM and ResinTransfer Molding 138
COSTING 138
13. Rotational Molding 140
INTRODUCTION 140
PROCESS 141
PLASTIC 145
PLASTIC BEHAVIOR 153
Effect of theThermalTreatment 155
Effect of Pigmentation and Mixing Method 157
Conclusion 157
PERFORMANCE 158
MACHINES 165
MOLD 169
DESIGN 172
PRODUCTIONAND COST 177
14. Compression Molding 178
INTRODUCTION 178
MOLD 185
MACHINES 188
PLASTIC 193

Contents xi
Polytetrafluoroethylene Billet 196
Hot Compression-Molding PTFE 203
PROCESSING 204
Heating 205
Automation 207
Transfer Molding 211
Compression-Injection Molding 212
Compression and lsostatic Molding 216
15. Reinforced Plastic 223
OVERVIEW 223
DEFINITION 225
Fibrous Composite 240
Laminar Composite 251
Particulate Composites 252
Fillers 252
PROPERTIES 254
ORIENTATION OF REINFORCEMENT 270
Directional Property 274
Hetergeneous/Homogeneous/Anisotropic 279
MATERIAL OF CONSTRUCTION 279
Prepreg 282
Sheet Molding Compound 283
Bulk Molding Compound 284
Compound 285
FABRICATING PROCESS 286
Preform Process 286
Type Process 288
Compression Molding 288
Hand Layup 291
FilamentWinding 295
Injection Molding 306
Marco Process 307
Pultrusion 307
Reactive Liquid Molding 309
Reinforced RTM 310
Reinforced Rotational Molding 311
SCRIMP Process 311
Soluble Core Molding 312
Spray-Up 312

xii Contents
Stamping 314
SELECTING PROCESSES 315
DESIGN 317
Aspect Ratio 317
Tolerance 329
ENGINEERINGANALYSIS 333
DesignTheory 333
16. Other Processes 335
INTRODUCTION 335
PVC PLASTISOL 336
Introduction 336
Processing Plastisol 338
Processing Organosol 340
Slush Molding 340
Rotational Molding 341
Spray Molding 342
Continuous Coating 342
Open Molding 342
Closed Molding 343
Dip Molding 343
Dip Coating 344
Heating System 344
INK SCREENING 344
ENCAPSULATION 344
POTTING 345
LIQUID INJECTION MOLDING 345
Vacuum-Assisted LIM 346
IMPREGNATION 346
CHEMICAL ETCHING 347
TWIN-SCREW INJECTION MOLDING 347
TEXTILE COVERED MOLDING 348
MELT COMPRESSION MOLDING 348
Back Injection 349
Melt Flow Compression Molding 351
Back Compression (Melt Compression Molding) 352
MCM-IML 352
PROCESSING COMPARISON 353

Contents xiii
17. Mold and DieTooling 366
OVERVIEW 366
MATERIAL OF CONSTRUCTION 382
STEEL 393
ALUMINUM 399
Preheating 402
Aluminum Zinc 403
COPPER 403
Beryllium Copper 404
Copper Zinc 404
OtherAlloys 404
METAL SPRAY 405
POROUS METAL 405
SOFTTOOLING 406
MANUFACTURING 406
Electric-Discharge Machining 408
Electroforming 408
SURFACE FINISH 408
POLISHING 410
Orange Peel 414
Art of Polishing 414
Hand Polishing 415
PROTECTIVE COATING/PLATING 416
Overview 416
Problems 418
Plating 422
Coating 423
HeatTreatment 425
Cryogenic Processing 426
MAINTENANCE/CLEANING 427
MOLD 429
Introduction 429
Basic Operation 460
Mold Components 460
MoldType 462
Injection Mold Feed System 472
Sprue 472
Runner 473
Gate 475
Cavity 488

xiv Contents
Cold Runner 491
Hot Runner 502
Runner Overview 512
Material of Construction 516
Cooling 519
CavityVenting 529
Ejection 533
Mold/Part Shrinkage 539
Mold Construction 544
ReleaseAgent 553
Faster/Lower-Cost Mold InsertApproach 554
Manufacturing Mold Cavity 554
Polishing 556
Preengineering 557
Safety 567
Moldmakers 569
Imports 570
Directories 570
Summary 572
DIES 573
Material of Construction 574
Terminology 575
Design 585
Melt Flow 585
Extrudate Performance 594
Manifold 598
Process Control 598
DieType 606
Tubular Dies 614
New Die Designs 633
COMPUTERS 634
ToolAnalysis 635
Model Construction 635
Software 636
Material Selection Software 636
TOOLINGAND PROTOTYPING 637
Rapid System 638
RapidTooling 640
Selecting RapidTooling 644
Rapid Prototyping 644

Contents xv
SoftwareTrend 645
REPAIRVERSUS BUYING 646
Welding 646
Storage 647
TOOL BUILDERS 647
GLOSSARY 648
APPENDIX 689
18. Auxiliary and Secondary Equipment 738
INTRODUCTION 738
MATERIAL/PRODUCT HANDLING 756
Material-Handling System 757
Injection Molding 777
Extruding 786
DECORATING 805
JOININGANDASSEMBLING 807
Adhesive and Solvent Bonding 807
MechanicalAssembly 835
Staking 849
WeldingAssembly 863
MACHINING 892
Overview 892
Machining and Cutting Operations 897
Machining andTooling 911
Machining NonmeltTP 919
Laser Machining 922
Other Machining Methods 923
Machining Safety 924
Glossary 925
Further Reading 953

Figure 10.1 Example of industrial coating and drying apparatus. 20
Figure 10.2 The basic drying process and typical drying parameters. 20
Figure 10.3 Temperature distribution in strippable vinyl foam. 44
Figure 10.4 High-speed extrusion coating line. 48
Figure 10.5 Example of roller coating processes. 49
Figure 10.6 Knife spread coating. 50
Figure 10.7 Transfer coating of PUR (top) and PVC. 50
Figure 10.8 Cast coating line for coating by transfer from paper carrier. 51
Figure 10.9 Fabric dip coating line. 52
Figure 10.10 Example of a vacuum coater. 53
Figure 10.12 Electrodeposition for application of coating to magnet wire or strip. 53
Figure 10.11 In-mold coating used in the reaction injection molding process. 53
Figure 10.13 Floor covering coating line. 54
Figure 10.14 Foam plastic carpet backing coating line. 54
Figure 10.15 Vacuum-ultraviolet radiation effects on organic coatings. 63
Figure 10.16 Vacuum-ultraviolet radiation effects on stabilized organic coatings. 63
Figure 10.17 Relationship between solar absorbance, total hemispherical emittance,
and pigment ratios. 64
Figure 10.18 Relationship between solar absorbance and pigment ratios. 64
Figure 10.19 Vacuum-ultraviolet radiation effects on inorganic coatings. 65
Figure 10.20 Effects of vacuum-ultraviolet radiation on pigments. 65
Figure 10.21 Emission ofVOCs in the life cycle of a varnish. 87
Figure 10.22 Pressure-temperature and pressure-density behavior of matter. 88
Figure 11.1 Example of the liquid casting process. 92
Figures

xviii Figures
Figure 11.2 Example of a LIM casting process. 95
Figure 11.3 Example of more accurate mixing of components for liquid injection
casting. 95
Figure 12.1 Example of typical PUR RIM process (courtesy of Bayer). 104
Figure 12.2 Diagram highlighting material use and handling in a PUR RIM process
(courtesy of Bayer). 104
Figure 12.3 Example of in-mold coating application. 105
Figure 12.4 Polyurethane RIM product for a computerized tomography (CT) device
Figure 12.5 Refrigerator with PUR foam door with no sheet metal (courtesy of Bayer). 107
Figure 12.6 RIM machine with mold in the open position (courtesy of Milacron). 110
Figure 12.7 RIM machine with mold in the closed position (courtesy of Milacron). 111
Figure 12.8 Example of an auto bumper RIM production line (courtesy of Milacron). 112
Figure 12.9 RIM machine with auxiliary clamping system (courtesy of Battenfeld). 113
Figure 12.10 Example of a RIM production line, where molds are on a moving track
permitting final cure of PUR (courtesy of Battenfeld). 114
Figure 12.11 Gating and runner systems demonstrating laminar melt flow and
uniform flow front (courtesy of Bayer). 115
Figure 12.12 Example of a dam gate and runner system (courtesy of Bayer). 116
Figure 12.13 Examples of triangular and quadratic fan gates (chapter 17; courtesy of
Bayer). 117
Figure 12.14 Example of melt flow around obstructions near the vent (courtesy of
Bayer). 118
Figure 12.15 Examples of various ribbing approaches to aid melt flow (courtesy of
Bayer). 118
Figure 12.16 Example of a low gate position with high vent for best results when
foaming (courtesy of Bayer). 119
Figure 12.17 Example of how to properly split a melt stream from the mixer
Figure 12.18 Basic schematic for mixing two liquid components to produce a PUR. 122
Figure 12.19 TDI is an isomer comprising toluene-2,4-and 2,6-diisocyanate. 126
Figure 12.20 Diphenylmethane-4,4-diisocyanate (MDI). 127
Figure 12.21 Examples of PUR RIM plastic products. 131
Figure 12.22 Density distribution across the thickness of a foamed part. 132
Figure 12.23 Molding pressure with RIM and RTM measures significantly less in other
processes (courtesy of Bayer). 138
Figure 13.1 RM’s four basic steps (courtesy ofThe Queen’s University, Belfast). 142
Figure 13.2 Rotational rate of the two axes is at 7:1 for this product. 146
Figure 13.3 Consumption of plastics for RM. 149
Figure 13.4 RM products in NorthAmerica. 149

Figures xix
Figure 13.5 RM products in Europe. 149
Figure 13.6 Example of RM products including large tank. 150
Figure 13.7 The effect of maximum inner temperature on the impact strength of the
moldings (a = PE and b = PP). 156
Figure 13.8 Effect of heating rate on the optimum processing temperature of PE. 156
Figure 13.9 Effect of the grinding temperature on the optimum processing
temperature of PE. 156
Figure 13.10 Effect of extrusion on the thermal properties of PE. 157
Figure 13.11 Effect of pigmentation on the thermal properties of turboblended PE. 157
Figure 13.12 Effect of pigmentation and mixing on the impact strength of PE. 158
Figure 13.13 Examples of similar-mold RM machine schematics. 160
Figure 13.14 Dual system with different-sized molds. 160
Figure 13.15 Schematic example of a multilayer RM machine. 161
Figure 13.16 Transfer of additional heat using a heat pipe. 165
Figure 13.17 Schematic of a basic three-station RM machine. 166
Figure 13.18 Example of a shuttle machine. 167
Figure 13.19 Example of a clamshell molding machine. 167
Figure 13.20 Example of a rock-and-roll molding machine. 168
Figure 14.1 Schematic of the CM of a plastic material. 178
Figure 14.2 Compression molded ring-shaped part removed from the mold. 179
Figure 14.3 CM using a molding compound. 182
Figure 14.4 CM using an impregnated material. 182
Figure 14.5 Examples of flash in a mold: (a) horizontal, (b) vertical, and (c) modified
vertical. 184
Figure 14.6 Positive compression mold. 186
Figure 14.7 Flash compression mold. 186
Figure 14.8 Semipositive compression mold. 187
Figure 14.9 Example of mold vent locations. 187
Figure 14.10 Example of vent locations in a mold processingTPs. 188
Figure 14.11 Example of land locations in a split-wedge mold (courtesy of National
Tool and ManufacturingAssociation). 189
Figure 14.13 The left side is a better edge design when using a draw angle. 190
Figure 14.12 Optimum draft for shear edges in molding sheet-molding compounds. 190
Figure 14.14 Knife shear edge. 190
Figure 14.15 Press with 4 × 4 in platens and ½-ton clamp pressure (courtesy of
Carver Press). 191
Figure 14.16 A 400-ton press with much larger than normal platens that measure
5 × 10 ft; the press has multiple zones of electrically heated platens, an
automatic bump cycle, an audible alarm to signal the end of the cure
cycle, and front and back safety-light curtains (courtesy ofWabash MPI). 191

xx Figures
Figure 14.17 A 4000-ton press with 5 × 8 ft platens (courtesy of Erie Press). 192
Figure 14.18 A 400-ton press with 18 platens, each measuring 4 × 6 ft (courtesy of
BaldwinWorks). 193
Figure 14.19 An 8000-ton press with 10 × 10 ft platens that have book-type opening
and closing action (courtesy of Krismer, Germany). 194
Figure 14.20 Processing sequence for compression stamping glass fiber–reinforcedTP
sheets. 195
Figure 14.21 Heat-curing cycles forTPs go throughA-B-C stages. 195
Figure 14.22 Transition point and linear thermal expansion of PTFE (courtesy of
DuPont). 199
Figure 14.23 Mechanism of sintering PTFE (courtesy of DuPont). 200
Figure 14.24 Example of a sintering cycle. 202
Figure 14.25 Example of a simple loading tray with a retractable slide plate to deliver
material to multicavity mold. 207
Figure 14.26 CM machine with preplasticizer. 208
Figure 14.27 Three screws of the preplasticizer have been retracted from their barrels
for viewing; not in the operating mode. 209
Figure 14.28 Preheated compounds exiting the preplasticizers prior to guillotine
slicing the required shot sizes. 210
Figure 14.29 Schematic of transfer molding. 211
Figure 14.30 Comparing IM, CM, and transfer molding. 211
Figure 14.31 Detail view of transfer molding with two cavities. 212
Figure 14.32 Example of a screw plasticizer preheating plastic that is delivered into
the transfer molding pot for delivery into the mold cavities. 212
Figure 14.33 A 64-cavity transfer mold about to receive electronic devices from a
work-loading frame. 215
Figure 14.34 Principal steps of isostatic molding. 217
Figure 14.35 Basic isostatic compaction process. 219
Figure 14.36 Three ways of molding PTFE tubes: (a) two flexible bags, (b) inner
flexible bag with outer rigid cylinder, and (c) outer flexible bag with
inner rigid rod. 220
Figure 15.1 Effect of matrix content on strength (F) or elastic moduli (E) of RPs. 223
Figure 15.2 Properties versus amount of reinforcement. 224
Figure 15.3 Glass fiber-TS polyester-filament-wound RP underground gasoline
storage tank. 226
Figure 15.4 Complete primary and secondary bus structure hand layup of glass
fiber-TS polyester RP. 226
Figure 15.5 Glass fiber swirl mat-TS polyester RP vacuum hand layup boat shell. 227
Figure 15.6 Glass fiber-TS polyester RP robot controlled hand layup 28 ft long boat. 227

Figures xxi
Figure 15.8 Glass fiber-TS polyester filament wound RP tank trailer that transports
corrosive and hazardous materials. 228
Figure 15.7 Glass fiber tape-TS polyester hand layup smoke stack liner. 228
Figure 15.9 Pultruded glass fiber roving-TS polyester rods in a 370 ft long lift bridge
supports up to 44T traffic load. 228
Figure 15.10 Glass fiber-TS polyester filament wound RP railroad hopper car body. 229
Figure 15.11 Monsanto House of the future all glass fiber-TS polyester RP hand
layup has four 16 ft long U-shaped (monocoque box girders) cantilever
structures 90° apart producing the main interior. 229
Figure 15.12 Interface of a RP. 230
Figure 15.13 Examples of reinforcement types and processing methods. 230
Figure 15.14 Fishbone diagram for an RP process (courtesy of Plastics FALLO). 231
Figure 15.15 Review of different processes to fabricate RP products. 231
Figure 15.16 Modulus of different materials can be related to their specific gravities
with RPs providing an interesting graph. 232
Figure 15.17 Short and long glass fiber-TP RP data (wt% fiber in parentheses). 246
Figure 15.18 Short to long fibers influence properties of RPs. 247
Figure 15.19 Specific tensile strength to specific tensile modulus of elasticity data f
nylon RPs. 247
Figure 15.20 Flexural fatigue data of woven glass fiber roving RPs. 247
Figure 15.21 Common glass fiber-TS polyester resin RP fatigue data versus other
materials (chapter 19). 248
Figure 15.22 Comparing different fiber material strength properties at elevated
temperatures. 248
Figure 15.23 Comparing whisker reinforcements with other reinforcements. 249
Figure 15.24 Schematic example in the manufacture of glass filaments/fibers. 249
Figure 15.25 Staple glass fiber and continuous glass filament fiber process methods. 272
Figure 15.26 Fiber arrangements and property behavior (courtesy of Plastics FALLO). 272
Figure 15.27 RP density versus percentage glass by weight or volume. 273
Figure 15.28 Fiber orientation provides different directional properties. 274
Figure 15.29 Examples of how fiber orientation influences properties of RPs. 275
Figure 15.30 Parallel/bidirectional layup of woven fabric 181 glass fiber (courtesy of
Plastics FALLO). 280
Figure 15.31 Parallel/unidirectional layup woven fabric 143 glass fiber (courtesy of
Plastics FALLO). 280
Figure 15.32 Ply layup at 0° and 90° woven fabric 143 glass fiber construction
(courtesy of Plastics FALLO). 281
Figure 15.33 Ply layup at 0°, 45°, 90°, and 135° woven fabric 143 glass fiber
construction (courtesy of Plastics FALLO). 281

xxii Figures
Figure 15.34 Sheet molding compound (SMC) production line using chopped glass
fiber including roving to provide bidirectional properties, cutting
continuous rovings for ease of mold-cavity fit. 282
Figure 15.35 These different SMC production lines produce by using chopped glass
fibers (top), including roving to provide bidirectional properties, cutting
continuous rovings so that they can fit easily in a mold cavity, and
producing thicker SMC (about 4 mm thick by 120 cm wide; bottom). 284
Figure 15.36 Flow of glass fiber rovings traveling through a plenum machine. 287
Figure 15.38 Flow of glass fiber rovings traveling through a water-slurry machine. 287
Figure 15.37 Flow of glass fiber rovings traveling through a direct machine. 287
Figure 15.39 Two-part compression mold. 289
Figure 15.40 Layout of reinforcement is designed to meet structural requirements. 293
Figure 15.41 Automated-integrated RP vacuum hand layup process that uses prepreg
sheets that are in the B-stage (chapter 1). 293
Figure 15.42 Schematic of hand-layup bag molding in an autoclave. 294
Figure 15.43 Early-twentieth-century tape-wrapping patent of a tube-making machine
by Hoganas-BillesholmsA.B., Sweden. 297
Figure 15.44 Views of fiber filament-wound isotensoid pattern of the reinforcing
fibers without plastic (left) and with resin cured. 301
Figure 15.45 Box winding machine with position changes of clamp tooling. 301
Figure 15.46 Schematics of “racetrack” filament-winding machines.Top view shows
machine in action; other view is a schematic of a machine built to
fabricate 150,000 gal rocket motor tanks. 304
Figure 15.47 Conventional single stage IMM. 306
Figure 15.48 IM with a preloader usually providing heat to the RP compound. 307
Figure 15.49 Schematics of ram and screw IMM. 308
Figure 15.50 Use is made of vacuum, pressure, or pressure-vacuum in the Marco
process. 309
Figure 15.51 Cutaway view of a reinforced RTM mold. 311
Figure 15.52 Lost-wax process fabricated a high-strength RP structural beam. 312
Figure 15.53 Nonatomized, dispensed Glass-Craft spray gun is easy to use and
produces low styrene emissions and is economic to maintain. 313
Figure 15.54 Example of the effect of shrinkage in the longitudinal and transverse
directions of a molded part. 319
Figure 15.55 Tensile stress-strain curves for epoxy-unreinforced and epoxy-reinforced
RPs and other materials. 322
Figure 15.56 Example of crack propagation to fracture that can occur, resulting in
product failure under load. 329
Figure 16.1 Effect of temperature on macromolecular characteristics of PVC plastisol. 337
Figure 16.2 Example of time-dependent viscosity of PVC plastisol. 338

Figures xxiii
Figure 17.1 Flow chart for typical tool activity. 379
Figure 17.2 Example of a steam chest mold for producing expandable polystyrene
(EPS) foams. 381
Figure 17.3 Examples of dimensional changes of tool materials subjected to heat treatment. 396
Figure 17.4 Terms identifying tool surface roughness perASA B46.1 standard. 411
Figure 17.5 Symbols identified on tool perASA B46.1 standard. 411
Figure 17.6 Illustrating roughness at a given point on a tool surface perASA B46.1
standard. 411
Figure 17.7 Polishability versus hardness. 412
Figure 17.8 Comparison of polishing tool hardness. 413
Figure 17.9 Cost of polishing tool steels. 413
Figure 17.10 Flow of the molding from the process that includes the mold to the
product. 430
Figure 17.11 Mold operation and types. 430
Figure 17.12 Examples of mold layouts, configurations, and actions. 431
Figure 17.13 Sequence of mold operations. 433
Figure 17.14 Mold action during a fabricating molding cycle. 433
Figure 17.15 Examples of precision mold half alignment. 434
Figure 17.16 Examples to simplify mold design and action. 436
Figure 17.17 Examples of different actions in molds. 438
Figure 17.18 Examples of unscrewing molds. 447
Figure 17.19 Examples of mold parts and molds. 450
Figure 17.20 Examples of mold force based on determining clamp force required for
melt flow. 456
Figure 17.21 Examples of melt flow’s path length as a function of part wall thickness
and injection pressures. 457
Figure 17.22 Example of an IM mold and a listing of its principal component parts. 461
Figure 17.23 Examples of two-plate molds. 463
Figure 17.24 Examples of three-plate molds. 466
Figure 17.25 Examples of stacked molds. 469
Figure 17.26 Examples of micromolded products compared to a US coin. 471
Figure 17.27 View of plastic flow from sprue to runner to gate to cavity. 472
Figure 17.28 Examples of cold and heated sprue designs. 473
Figure 17.29 Examples ofTP balanced cold runners that include primary and
secondary runners. 474
Figure 17.30 Example of a cold runner mold for processingTS plastics. 475
Figure 17.31 Examples of various gate types. 476
Figure 17.32 Melt flow pattern in cavity can relate to gate-flow pattern based on
single gate (left) or multiple gates. 477

xxiv Figures
Figure 17.33 Gate temperature/pressure/temperature relationships for amorphous
and crystalline plastics are shown. 478
Figure 17.34 Schematic of gate land location. 479
Figure 17.35 Schematic of heated single-edge gate. 481
Figure 17.36 Schematic of heated double-edge gate. 482
Figure 17.37 These molded test specimens highlight melt flow direction from a gate
or gates. 483
Figure 17.38 Cavity arrangement in balanced and unbalanced runner layouts. 489
Figure 17.39 Example of a melt flow fountain (or balloon) pattern across the thickness
in a mold cavity. 490
Figure 17.40 Examples of cold runner feed systems. 492
Figure 17.41 Common runner configurations. 493
Figure 17.42 Equivalent hydraulic diameters for common runner configurations. 494
Figure 17.43 Balanced cold runner with edge gates. 495
Figure 17.44 Example of dissimilar cavities in a family mold. 495
Figure 17.45 Examples of unbalanced cold runner molds. 496
Figure 17.46 Examples of melt viscosity data. 497
Figure 17.47 Balanced runner system in an eight-cavity mold. 498
Figure 17.48 Unbalanced runner system in a six-cavity mold. 501
Figure 17.49 Unbalanced runner system in a ten-cavity mold. 502
Figure 17.50 Schematics of hot runner mold systems. 503
Figure 17.51 Internally heated hot manifold. 504
Figure 17.52 Insulated hot runner systems. 505
Figure 17.53 Examples of direct hot runner gates. 506
Figure 17.54 Advanced types of hot runner gates. 506
Figure 17.55 Example of a hot manifold support system. 507
Figure 17.56 Example of a hot manifold stack mold with ninety-six cavities. 508
Figure 17.57 Example of a twelve-cavity hot manifold stack mold. 509
Figure 17.58 Heated manifold forTP hot runner system. 514
Figure 17.59 Cooling arrangements for cores of various sizes. 520
Figure 17.60 Cooling channel considerations. 521
Figure 17.61 Poor and good cooling channel layouts. 522
Figure 17.62 Schematic of laminar flow (left) and turbulent flow (right) in coolant
channels. 522
Figure 17.63 Heat-transfer characteristics in a typical hot runner mold (courtesy of
Husky Injection Molding Systems Inc.). 525
Figure 17.64 Examples of mold-cooling components. 526
Figure 17.65 Nomogram guide for determining cooling channels. 527
Figure 17.66 Without proper venting, air entrapment can occur in the mold cavity. 529

Figures xxv
Figure 17.67 Examples of recommended vent dimensions for PP (top view) and other
TPs. 530
Figure 17.68 Examples of vents. 531
Figure 17.69 Example of a vent pin used to break the vacuum between core and plastic. 532
Figure 17.70 Sequence in ejection molded parts using ejection pins. 534
Figure 17.71 Operation of ejector pins (courtesy of Husky Injection Molding
Systems Inc.). 536
Figure 17.72 Operation of stripper plate (courtesy of Husky Injection Molding
Systems Inc.). 536
Figure 17.73 Hydraulic operation of stripper plate (courtesy of Husky Injection
Molding Systems Inc.). 537
Figure 17.74 Chain operation of stripper plate. 537
Figure 17.75 Ejection system incorporating blades. 538
Figure 17.76 Flexible molded parts can easily be ejected from the mold cavity. 538
Figure 17.77 View of undercut that ensures molded part is retained in female cavity.
Data on undercuts that are strippable. 539
Figure 17.78 Examples of dimensional changes of annealed nylon 6/6 versus
temperature at various humidities. 540
Figure 17.79 Nylon 6/6 shrinkage due to annealing versus mold temperature. 541
Figure 17.80 This nomograph for nylon estimates shrinkages. 543
Figure 17.81 Shrinkage as a function of part thickness and gate area. 544
Figure 17.82 Molds can be cored to eliminate or reduce shrinkage. 544
Figure 17.83 Example of shrinkage control and mold dimensions. 545
Figure 17.84 Example of a simplified unscrewing bottle cap mold. 545
Figure 17.85 Examples of sprue pullers. 550
Figure 17.86 Example of the location for a mold pressure transducer sensor. 551
Figure 17.87 Guide to mold alignment. 551
Figure 17.88 Examples of only a few of the many preengineered mold component
parts and devices. 559
Figure 17.89 Preengineered spiral flow test mold. 567
Figure 17.90 Example of an extrusion line that includes a die and downstream
equipment. 573
Figure 17.91 Some identifying terms for dies; other terms are described in the text. 576
Figure 17.92 Location of the extrusion die land. 582
Figure 17.93 Examples of melt flow patterns in a coat hanger die. 586
Figure 17.94 Examples of melt distribution with die geometry via their manifold
channels. Each die has limitations for certain types of melts. 586
Figure 17.95 Examples of melt flow patterns based on minimum die and process
control. 587
Figure 17.96 Schematic of wall-thickness control for extruding blow molded parisons. 589

xxvi Figures
Figure 17.97 Examples of nonstreamlined and streamlined entrances in dies. 590
Figure 17.98 Flow coefficients calculated at different aspect ratios for various shapes
using the same equation. 593
Figure 17.99 Calculation for the volumetric melt flow rate for this specific shape. 594
Figure 17.100 Shown are the (more conventional) rigid and die-lip lands. 595
Figure 17.101 Example of the land in an extrusion blow molding die that is usually
from 10:1 to 20:1 ratio. 596
Figure 17.102 Examples of different profiles that include using lands of different
configurations. 597
Figure 17.103 Honing extrusion coater die land. 599
Figure 17.104 Schematic of feedblock sheet die. 599
Figure 17.105 Example of a dual chamber of a feedblock and die assembly. 600
Figure 17.106 Specially designed Proteus feedblock (courtesy of EDI). 601
Figure 17.107 Example of heating different dies. 602
Figure 17.108 Melt flow rates versus melt pressure in die openings. 603
Figure 17.109 Examples of flat dies with its controls. 609
Figure 17.110 Examples of deckles that are adjusted during processing (top) and
manually adjusted off-line. 610
Figure 17.111 Examples of a flat die’s automatic control systems. 611
Figure 17.112 Cutaway view of a coat hanger sheet die with a restrictor bar. 612
Figure 17.113 Example of a straight coating or laminating manifold die. 613
Figure 17.114 Examples of a crosshead coating dies. 613
Figure 17.115 Examples of single-layer blown-film dies include side-fed typex (top
left), bottom-fed types with spiders (top center), and spiral-fed types. 614
Figure 17.116 Examples of different pipe die designs. 617
Figure 17.117 Different views of assembled and disassembled profile dies. 618
Figure 17.118 Examples of wire coating dies. 619
Figure 17.119 Schematic for determining wire coated DRB in dies. 620
Figure 17.120 Schematic for determining wire coating DDR in dies. 621
Figure 17.121 Examples of netting and other special forms. 622
Figure 17.122 Examples of underwater pelletizer dies. 624
Figure 17.123 Examples of coextruded dies. 625
Figure 17.124 Examples of feedblock multimanifold coextrusion dies. 629
Figure 17.125 Schematic of the RV feedblock showing melt paths and assembled
RV feedblock with layer control plates and skin flow inserts in the
foreground (courtesy of Davis-Standard). 630
Figure 17.126 Example of a coextrusion combining adapter. 631
Figure 17.127 Examples of layered plastics based on four modes of die rotation. 632
Figure 17.128 Example of the multilayer blown-film die. 632
Figure 17.129 Displacement of layers leaving an extruder film die. 633

Figures xxvii
Figure 17.130 New coextrusion die design (left) is compared to the traditional flat-
plate die. 634
Figure 18.1 Example ofAE required for plastics going from a railcar to a silo. 744
Figure 18.2 Closeup view of a piping system to and from silos, with each having a
capacity of 2000 lb. 745
Figure 18.3 Examples of plant layout with extrusion and injection molding primary
andAE. 746
Figure 18.4 Example of an extrusion laminator withAE. 747
Figure 18.5 Example of a blow-molding extruder withAE (rolls, turret winder, etc.). 748
Figure 18.6 Example of an extruder coater withAE. 749
Figure 18.7 Example of plant layout with injection molding primary andAE. 749
Figure 18.8 Example of extruded products requiringAE. 750
Figure 18.9 Example of ventilationAE used with an injection molding machine
(courtesy of Husky Injection Molding Systems Inc.). 751
Figure 18.10 Examples of material handling AE used with an injection molding
machine (courtesy of Husky Injection Molding Systems Inc.). 752
Figure 18.11 Example of a pneumatic vacuum venturi flow system. 757
Figure 18.12 Example of continuous pressure pellets with rates based on polystyrene
at 35 lb/ft3 (560 kg/m3). 760
Figure 18.13 Example of continuous vacuum pellets with rates based on polystyrene
at 35 lb/ft3 (560 kg/m3). 761
Figure 18.14 Example of continuous vacuum powder with rates based on polyvinyl
chloride (PVC) at 35 lb/ft3 (560 kg/m3). 762
Figure 18.15 Example of a 10 hp vacuum system conveying polystyrene at 35 lb/ft3
(560 kg/m3). 763
Figure 18.16 Example of a 25 hp vacuum system conveying polystyrene at 35 lb/ft3
(560 kg/m3). 764
Figure 18.17 Example of a single pneumatic material-handling line-feeding hoppers. 768
Figure 18.18 Example of the front and side views of a basic hopper. 769
Figure 18.19 Introduction to hopper mixers. 770
Figure 18.20 Example of a dump-type hopper loader. 770
Figure 18.21 Example of a screw-controlled feeding loader (courtesy of Spirex
Corporation). 771
Figure 18.22 Detail view of a hopper screw-controlled feeding loader. 771
Figure 18.23 Example of components in a hopper blender. 772
Figure 18.24 Example of metering a color additive in a blender. 773
Figure 18.25 Example of a hopper power-pump loader. 773
Figure 18.26 Example of a vacuum hopper-loading cycle. 774
Figure 18.27 Systems utilizing a rotary air lock feeder to separate pressure and
vacuum airflow. 775

xxviii Figures
Figure 18.28 Examples of coarse, dusty, and powder material-filtering systems. 776
Figure 18.29 Example of a positive take-out and transfer mechanism for molded
products (courtesy of Husky Injection Molding Systems Inc.). 778
Figure 18.30 Example of a positive take-out system to handle and pack molded
Figure 18.31 Example of a free-drop take-out and transfer mechanism of molded
products. 780
Figure 18.32 Example of an unscramble-and-orient system for molded products
(courtesy of Husky Injection Molding Systems Inc.). 781
Figure 18.33 Example of bulk filling with automatic carton indexing of molded
Figure 18.34 Example of flow of material to shipping of molded products. 782
Figure 18.35 Example of a robot removing parts from a mold and depositing them in
orderly fashion in a container. 783
Figure 18.36 Mold base en route manually to injection molding press. 788
Figure 18.37 Mold base placed manually to the right in injection molding press. 789
Figure 18.38 Fully automatic horizontal mold change (courtesy of Staubli Corp.,
Duncan, South Carolina). 790
Figure 18.39 Fully automatic overhead-crane mold change. 790
Figure 18.40 Examples of tension-control rollers in a film, sheet, or coating line. 791
Figure 18.41 Example of laminating with an adhesive. 791
Figure 18.42 Example of roll-change-sequence winder (courtesy of Black Clawson). 791
Figure 18.43 Closeup view of a tension roll that is processing plastic film. 792
Figure 18.44 Example herringbone idler reducing wrinkles of web. 792
Figure 18.45 Examples of drum-cooling designs with shell cooling being the best
design. 793
Figure 18.46 Examples of matted and unmatted embossing rolls. 793
Figure 18.47 Example of a wood-grain embossing roll. 794
Figure 18.48 Example of ultrasonically sealing a decorative pattern. 794
Figure 18.50 Example of a dancer roll controlling tension in an extruded sheet line. 795
Figure 18.51 Example of an extruded sheet line turret wind-up reel change system. 795
Figure 18.49 Guide to sheet-polishing roll sizes with a 450°F (230°C) melt temperature. 795
Figure 18.52 View of a large single winder at the end of an extruder sheet line
(courtesy ofWelex). 796
Figure 18.53 View of a large dual-turret winder at the end of an extruder sheet line. 797
Figure 18.54 View of a sheet roll stock extruder winder with triple fixed shafts
(courtesy ofWelex). 798
Figure 18.55 View of downstream extruder-blown film line going through control
rolls and dual wind-up turrets (courtesy ofWindmoeller & Hoelscher
Corporation). 799

Figures xxix
Figure 18.56 Examples of pipe-extrusion caterpillar puller with rollers and conveyor
belts. 800
Figure 18.57 Description of a caterpillar belt puller used in an extruder line (courtesy
of Conair). 801
Figure 18.58 Description of a vacuum sizing tank used in an extruder line (courtesy of
Conair). 801
Figure 18.59 Description of a water-and-spray tank used in an extruder line (courtesy
of Conair). 802
Figure 18.60 Description of a rotary knife cutter used in an extruder line (courtesy of
Conair). 802
Figure 18.61 Description of a pneumatic-stop rotary knife cutter used in an extruder
line (courtesy of Conair). 803
Figure 18.62 Description of a traveling up-cut saw used in an extruder line (courtesy
of Conair). 803
Figure 18.63 Description of a product takeaway conveyor used in an extruder line
(courtesy of Conair) 804
Figure 18.64 Examples in the use of masking for paint spraying. 814
Figure 18.65 Examples of paint spray-and-wipe. 815
Figure 18.66 Examples of screen printing. 815
Figure 18.67 Example of hot stamping using a roll-on technique. 815
Figure 18.68 Example of pad transfer printing. 816
Figure 18.69 Joining and bonding methods. 830
Figure 18.70 Examples of joint geometries. 831
Figure 18.71 Examples of corona treatments in extrusion lines. 839
Figure 18.72 Guide for molding threads. 852
Figure 18.73 Examples of assembling all plastic and plastic to different materials
where thermal stresses can become a problem when proper design is not
used (chapter 19). 853
Figure 18.74 Examples of self-tapping screws. 855
Figure 18.75 Molded-in insert designs. 856
Figure 18.76 Examples of metal-expansion types of slotted and nonslotted inserts. 859
Figure 18.77 Examples of press-fit-stress analyses (courtesy of Bayer). 861
Figure 18.78 Examples of cantilever beam snap-fits. 863
Figure 18.79 Example of cold staking of plastic. 864
Figure 18.80 Example of hot staking of plastic. 864
Figure 18.81 Example of hot-plate welding. 869
Figure 18.82 Film-welded, 8-ply arrangement using a Doboy thermal welder. 872
Figure 18.83 Example of a manual hot-gas welding. 874
Figure 18.84 Example of an automatic hot-gas welder; hot gas blown between sheets,
which melt and flow together. 874

xxx Figures
Figure 18.85 Example of design joints for hot-gas welding. 875
Figure 18.86 Examples of visually examining hot-gas weld quality. 875
Figure 18.87 Example of linear-vibration welding. 876
Figure 18.88 Penetration-versus-time curve showing the four phases of vibration welding. 876
Figure 18.89 Spin welding, where one part does not move and the other part rotates. 881
Figure 18.90 Example of a joint used in spin welding. 881
Figure 18.91 Components of an ultrasonic welder. 882
Figure 18.92 Stages in ultrasonic welding. 883
Figure 18.93 Examples of plastic mating joints to be ultrasonically welded. 884
Figure 18.94 Example of induction heat produced during induction welding. 886
Figure 18.95 Example of induction welding a lid to a container. 886
Figure 18.96 The three steps in resistance welding. 890
Figure 18.97 Example of an extrusion-welding system, where the hot air melts the
plastic to be welded prior to the extruded melt flows into the area. 891
Figure 18.98 Examples of cutting and punching in-line, extrudedTPs. 895
Figure 18.99 Example of extrusion in-line shear cutter with sheets being stacked. 897
Figure 18.100 Guide to slitting extruded film or coating. 909
Figure 18.101 Schematics of cutting-tool actions. 911
Figure 18.102 Basic schematic of a cutting tool. 913
Figure 18.103 Example of forces acting on a tool. 914
Figure 18.104 Example of wear pattern. 915
Figure 18.105 Nomenclature for single-point tools. 918
Figure 18.106 Nomenclature of twist drills. 918
Figure 18.107 Nomenclature of milling cutters. 919
Figure 18.108 Cutting tool for machining (skiving) tape from a molded plastic block. 922

Table 10.1 Examples of different coating materials 3
Table 10.2 Important coating compounds and applications 6
Table 10.3 Environmental performance of some coating materials 9
Table 10.4 Survey of often-used coating systems for concrete 11
Table 10.5 Wet coating materials for metals 11
Table 10.6 Examples of coating materials including those containing solvents 12
Table 10.7 Typical release coating systems and applications 14
Table 10.8 Example of paint and varnish coating compositions 16
Table 10.9 Examples of solvents and their behaviors 18
Table 10.10 Examples of coating performances 21
Table 10.11 General performance comparisons 29
Table 10.12 General composition of dispersion coatings 30
Table 10.13 Example of advantages using dispersion coatings 30
Table 10.14 Examples of properties for Parylenes N and C 38
Table 10.15 Effect of various sterilization methods for Parylenes N and C 38
Table 10.16 Guide for applying paint coatings to plastic substrates 40
Table 10.17 Surface energy of plastics as a result of fluorination 40
Table 10.18 Typical plastics used in coil coatings 41
Table 10.19 Coil coating plastic characteristics and applications 42
Table 10.20 Plastic properties of coil coatings 43
Table 10.21 Coating methods related to performances 46
Table 10.22 Examples of spray coating methods related to transfer efficiency 55
Table 10.23 Plastic coating property guide 66
Table 10.24 Examples of acids and bases pH 76
Tables

xxxii Tables
Table 10.25 Color indicators of acids and bases pH 77
Table 10.26 Classifications and definitions of solvents 81
Table 10.27 Examples of basic calculations ofVOC-emissions during applications of
emulsion paints 86
Table 10.28 Critical properties of solvents 89
Table 12.1 Information on computerized tomography (CT) devices (courtesy of
Bayer) 106
Table 12.2 Information on GMP’s patented refrigerator door technique 108
Table 12.3 Calculations for determining dimensions for a dam gate (courtesy of
Bayer) 120
Table 12.4 Calculations for determining dimensions for a quadratic gate (courtesy
of Bayer) 121
Table 12.5 Terminology of chemical and other terms 125
Table 12.6 Structural foam information for large, complex products 128
Table 12.7 John Deere rear shield made from a soy-based structural foam PUR RIM
formulation 129
Table 12.8 Chemical reaction review 135
Table 12.9 Example of cost analysis of PUR RIM and injection molding of products
with large surface areas 139
Table 13.1 Comparison of different processes 141
Table 13.2 Tack temperatures for different plastics 142
Table 13.3 Relative time to reach two tack temperatures at different oven
temperatures 143
Table 13.4 Heat transfer coefficients during mold cooling 143
Table 13.5 Steps taken during the RM fabrication process 144
Table 13.6 Effect of oven heat time on RM plastics 145
Table 13.7 Examples of rotational ratios for different shapes 146
Table 13.8 Effect of oven condition on foaming high-density PE (HDPE) 147
Table 13.9 Examples of RM products 148
Table 13.10 Examples of PVC plastics used in RM 150
Table 13.11 Sieve sizes 151
Table 13.12 Classifying particle shape for irregular particles 151
Table 13.13 Typical powder bulk density 152
Table 13.14 Comparing powders with micropellets 153
Table 13.15 Types of powder flow 154
Table 13.16 Property changes with increasing PE density (chapter 2) 159
Table 13.17 Property changes with increasing melt index (chapter 22) 159
Table 13.18 Recommended draft angles for RM plastics 163
Table 13.19 Recommended draft angles for smooth and textured (0.1 mm texture
depth) molds 163

Tables xxxiii
Table 13.20 Examples of warpage standards for RM plastics 164
Table 13.21 Guide for inner and outer radiuses in RM dimensions 164
Table 13.22 Properties of mold materials 169
Table 13.23 Plaster casting materials 169
Table 13.24 Heating cycle times for aluminum molds 170
Table 13.25 Steel sheet-metal gauge 170
Table 13.26 RM mechanical design aspects 173
Table 13.27 Wall-thickness range for RM plastics 176
Table 13.28 Guide to linear shrinkage values for RM plastics 176
Table 14.1 Example of applications for compression molded thermoset (TS) plastics 180
Table 14.2 Comparing compression molded properties with other processes 180
Table 14.3 Relating materials to properties to processes 181
Table 14.4 Examples of the effect of preheating and part depth of phenolic parts on
CM pressure (psi) 183
Table 14.5 Examples of OD, ID, height, and weight relationships of different PTFE
billet CMs 197
Table 14.6 Examples of PTFE sintering conditions 201
Table 14.7 Effect of cooling rate on crystallinity, typical for granular molding
powders (courtesy of DuPont) 202
Table 14.8 Effect of CM processes on properties (courtesy of DuPont) 204
Table 14.9 Guide to wall-thickness tolerance for CM different plastics 205
Table 14.10 Guide in the use of reinforcements and fillers in different molding
compounds 206
Table 14.11 Transfer molding compared to CM 213
Table 14.12 Transfer molding compared to reinforced plastic molding 214
Table 14.13 Examples of isostatically molded parts 217
Table 14.14 Isostatic mold design considerations 222
Table 15.1 Types of composites 224
Table 15.2 Examples of composite ablative compounds 224
Table 15.3 Examples of reinforcement types and processing methods 232
Table 15.4 Examples of RTP properties 233
Table 15.5 TP-glass fiber RPs injection molding (IM) temperatures 234
Table 15.6 Examples of properties and processes of RTS plastics 235
Table 15.7 Properties of the popularTS polyester-glass fiber RPs 235
Table 15.8 Different properties of RTPs and RTSs perASTM standards 236
Table 15.9 Properties of fiber reinforcements 240
Table 15.10 Reinforcement thermal properties 240
Table 15.11 Properties of glass-fiber RPs 241
Table 15.12 Comparative yarn properties 242
Table 15.13 Examples of different carbon fibers 242

xxxiv Tables
Table 15.14 Aramid fiber-TP RP properties 242
Table 15.15 Properties of unidirectional hybrid-nylon RPs 243
Table 15.16 Charpy impact test results of square woven fabric using hybrid fibers-
nylon RPs 244
Table 15.17 Damage propagation of aramid and E-glass RPs using tensile-notched
test specimens 244
Table 15.18 Examples of different glass fiber yarns 244
Table 15.19 Examples of glass fiber staple fiber yarn data 245
Table 15.20 Examples of glass fiber cloth constructions 246
Table 15.21 Examples of fillers used inTP RPs (chapter 1) 253
Table 15.22 Examples of fillers used inTS RPs (chapter 1) 253
Table 15.23 Comparison of tensile properties in RPs, steel, and aluminum 254
Table 15.24 Mechanical properties of resins that are reinforced to increase properties 255
Table 15.25 Properties perASTM of 30 wt% glass-fiber RTPs 256
Table 15.26 Properties of glass-fiber RTPs with different glass fiber contents and
other reinforcements 257
Table 15.27 Properties of short and long glass fiber-nylon 6/6 RPs at elevated
temperatures 257
Table 15.28 Examples of obtaining desired properties ofTP-RPs 258
Table 15.29 Properties of RPs with 30 wt% to 50 wt% glass fiber-TS polyester based
on fabricating process 259
Table 15.30 Properties ofTS polyester RPs with different amounts of glass fibers 260
Table 15.31 Properties of glass fiber mats RPs with different types ofTS polyesters 261
Table 15.32 General properties ofTS RPs perASTM testing procedures 262
Table 15.33 Examples of mechanical properties ofTS RPs at ambient and elevated
temperatures 264
Table 15.34 Flexural modulus of glass-polyester–RPs exposed to various
environmental elements 265
Table 15.35 Strength and modulus for glass fiber-TS RPs at low temperature 266
Table 15.36 Coefficients of thermal expansion for parallel glass fiber-TS RPs 267
Table 15.37 Example ofTS RPs for electrical applications 268
Table 15.38 Mechanical properties of glass fabric-TS polyester RPs exposed to
various intensities of near-UV radiation in a vacuum 269
Table 15.39 Mechanical properties of glass fiber fabric-TS polyester RPs after
irradiation at elevated temperatures 270
Table 15.40 Properties of different materials 271
Table 15.41 Properties of unidirectional RPs using different types of fibers 276
Table 15.42 Properties of unidirectional graphite fiber-thermoplastic RPs varying in
resin content by weight and varying in void content by volume (at 72°F
and 350°F) 277

Tables xxxv
Table 15.43 Comparing properties of SMC with steel 283
Table 15.44 Filament-wound structures for commercial and industrial applications 296
Table 15.45 Filament-wound structures for aerospace, hydrospace, and military
applications 297
Table 15.46 Different FW patterns meet different performance requirements 298
Table 15.47 RP processing guide to RP process selection 316
Table 15.48 RP processing guide to RP size 317
Table 15.49 Examples of a few processes to material comparisons 318
Table 15.50 RP resin transfer, SMC compression, and IM processes compared 319
Table 15.51 Examples of RTS plastic processes 320
Table 15.52 Comparing uses of different plastics with different RP and other processes 321
Table 15.53 Examples of interrelating product-RP material-process performances 322
Table 15.54 Comparison of RP design aspects and processes to cost 323
Table 15.55 Examples of processing variables 325
Table 15.56 Product design versus processing methods 326
Table 15.57 Other product design considerations versus processing methods 327
Table 15.58 Product design shapes versus processing methods 328
Table 15.59 Examples of the efficiency RPs fiber orientation 329
Table 15.60 Example ofTS polyester volume shrinkage during curing 330
Table 15.61 RPs wall-thickness tolerances 331
Table 15.62 Comparing unreinforced and RP mold shrinkage rates 332
Table 15.63 Composite efficiency of RPs 334
Table 15.64 Examples of loading conditions 334
Table 16.1 Example of a PVC blend formulation 343
Table 16.2 Automotive industry objectives for decorative plastics 349
Table 16.3 Definitions applicable to low-pressure decorating molding 350
Table 16.4 Example of an MCM-IML molding cycle 352
Table 16.5 Examples of MCM-IML advantages and applications 353
Table 16.6 Examples of valid reasons for using MCM-IML 354
Table 16.7 Examples of invalid reasons for using MCM-IML 354
Table 16.8 Process and materials composition 355
Table 16.9 Processing, materials, and geometry 355
Table 16.10 Geometry function and complexity 356
Table 16.11 Listing of abbreviations used in the following tables 357
Table 16.12 Reactive liquid composite molding 358
Table 16.13 Multimaterial multiprocess (MMP) technology 359
Table 16.15 TP sheet composite 360
Table 16.14 Fusible core IM 360
Table 16.16 Gas-assisted IM: process and simulation 361
Table 16.17 Low-pressure molding 362

xxxvi Tables
Table 16.18 Advanced blow molding 363
Table 16.19 Microcellular plastic: formation and shaping 364
Table 16.20 Lamellar IM 365
Table 17.1 Types of tools and materials 367
Table 17.2 American Iron and Steel Institute (AISI) and some BS numbers without
their “B” prefix (BH10A/H10A) with comparableWerkstoff numbers
and their mean (average) chemical compositions 371
Table 17.3 Werkstoff numbers with comparableAISI numbers or a near-matching
chemical composition 374
Table 17.4 Elements and their symbols 376
Table 17.5 Examples of different metals used in tools 377
Table 17.6 Examples of mold and die tools for different fabricating processes 378
Table 17.7 Examples of cost comparison of molds in terms of the properties of plastic 380
Table 17.8 Typical properties of various RP mold bag materials 381
Table 17.9 Examples of the properties of different tool materials 383
Table 17.10 Guide to different tool materials, where 5 is best 384
Table 17.11 Examples of improving/changing properties of tool materials via alloying 384
Table 17.12 Example of costs and properties of tool materials, including alloys 385
Table 17.13 Hardness of tool materials for a few different plastic materials and
processes 385
Table 17.14 Example of tool materials arranged in order of hardness 386
Table 17.15 Different hardness conversions 387
Table 17.16 Thermal conductivity of tool materials 388
Table 17.17 Thermal-expansion coefficients of tool materials 389
Table 17.18 HRC file check 389
Table 17.19 Example of a schedule, in weeks, for purchasing of a mold 390
Table 17.20 Guide for mold construction 390
Table 17.22 Example of a mold progress report 391
Table 17.21 Example of a mold checklist 391
Table 17.23 Example of a detailed mold progress report 392
Table 17.25 Properties of the more popular tool materials 394
Table 17.26 Examples of tool steels with applications 395
Table 17.27 Examples of tool steel alloys (first two digits denote type of steel; second
two digits indicate carbon weight percentage) 396
Table 17.28 Property comparison of aluminum and steel 401
Table 17.29 Strength of aluminum based on thickness 401
Table 17.30 Wrought aluminum performance 402
Table 17.31 Properties of beryllium copper versus other tool materials 404
Table 17.32 Various heat treatments versus finish of Uddeholm tool steels 409
Table 17.34 Identification of surface finish based on manufacturing process 409

Tables xxxvii
Table 17.33 Different grain standards used for surface finishes 409
Table 17.35 Diamond-particle compound relates to surface finish 410
Table 17.36 Polishing sequences 412
Table 17.37 Examples of coatings based on material used 418
Table 17.38 Examples of coatings based on process used 419
Table 17.39 Guide to tool surface enhancements and coatings commonly used
(courtesy of Eastman Chemical Co./431) 420
Table 17.40 Examples of coating materials for tools 423
Table 17.41 Examples of cleaning methods 428
Table 17.42 Examples of tapers for cavity sidewalls 434
Table 17.43 Examples of pressures applied to molds 456
Table 17.44 Examples of plastic mold temperatures and pressure requirements 456
Table 17.45 Basic mold component operations 458
Table 17.46 Guidelines for melt shear rates (courtesy of Synventive Molding Solutions) 485
Table 17.47 TP melt temperatures (°C) 486
Table 17.48 Guide to size of round runners 493
Table 17.49 Property comparison of some mold construction materials 517
Table 17.50 Applications of principal mold steels 518
Table 17.51 Guide to cooling channel diameters for PP (see Fig. 17.61) 522
Table 17.52 Examples of factors that influence PP shrinkage 545
Table 17.53 Guide for mold shrinkage of ¼ and ½ in thick specimens perASTM
D 955 546
Table 17.54 Guide for mold shrinkage for different thickness dimensions 547
Table 17.55 Examples of error in mold size as a result of using incorrect shrinkage
formulas 548
Table 17.56 Checklist and guideline for operating a mold 568
Table 17.57 SPI Moldmakers Division quotations guide 571
Table 17.58 Examples of operational effects and geometrical variables on melt flow
conditions in a die 592
Table 17.59 Examples of melt shear rates 604
Table 17.60 Examples of the effect of shear rate on the die swell ofTPs 604
Table 17.61 Examples of extrusion dies from Extrusion Dies Inc. 607
Table 17.62 Guide to different pellets that are fabricated from different performing
dies 623
Table 17.63 Examples of blown-film applications for coextrusion 628
Table 17.64 Rapid prototyping processes 638
Table 17.65 Checklist procedure for mold repair (courtesy of Synventive Molding
Solutions) 670
Table 17.66 Example of SPI’s moldmakers directory for services 671
Table 17.24 Tool materials with near-matching chemical compositions 689

xxxviii Tables
Table 18.1 Example of manufacturing cycle that includes equipment 739
Table 18.2 SPE auxiliaries buyer’s guide (courtesy of SPE) 740
Table 18.3 Introduction to auxiliary and SE performances 754
Table 18.4 Examples of auxiliary and SE 755
Table 18.5 Estimated annual savings for energy-efficient electric motors (Electrical
Apparatus ServiceAssociation) 765
Table 18.6 Examples of the usual functions of robots and perimeter guarding 784
Table 18.7 Examples of comparing robots with other parts-handling systems 786
Table 18.8 Examples of types of robots manufactured 787
Table 18.9 Examples of different rolls used in different extrusion processes 806
Table 18.10 Guide to decorating 808
Table 18.11 Examples of methods for decorating plastic products after fabrication 810
Table 18.12 Examples of methods for decorating plastic products in a mold 811
Table 18.13 Guide in comparing a few decorating methods from size to cost 812
Table 18.14 Review of a few decorating methods 813
Table 18.15 Examples of joining methods 817
Table 18.16 Examples of joiningTPs andTSs 817
Table 18.17 Examples of descriptions for different joining methods 818
Table 18.18 Directory of companies that provide joining and assembling methods 820
Table 18.19 Examples of adhesives for bonding plastics to plastics 826
Table 18.20 Examples of bondingTPs to nonplastics 829
Table 18.21 Examples of bondingTS plastics to nonplastics 829
Table 18.22 Adhesive terminology 832
Table 18.23 Example of adhesives classified by composition 834
Table 18.24 Plasma treatment 836
Table 18.26 Peel strength of plastics after plasma treatment perASTM test methods 837
Table 18.25 Lap shear strength of plastics after plasma treatment perAmerican
Society forTesting Materials (ASTM) test methods 837
Table 18.27 Shear strength of PP to PP adhesive bonds in psi (MPa) perASTM D 4501 838
Table 18.28 Shear strength of polyethylene (PE) to PE in psi (MPa) 840
Table 18.29 Shear strength ofABS toABS in psi (MPa) 841
Table 18.30 Shear strength of PP to PP in psi (MPa) 842
Table 18.31 Shear strength of PVC to PVC in psi (MPa) 843
Table 18.32 Shear strength of polycarbonate (PC) to PC in psi (MPa) 844
Table 18.33 Shear strength of PUR to PUR in psi (MPa) 845
Table 18.34 Shear strength of PA to PA in psi (MPa) 846
Table 18.35 Shear strength of polyimide to polyimide in psi (MPa) 847
Table 18.36 Shear strength of acetal to acetal in psi (MPa) 848
Table 18.37 Shear strength of polymethyl methacrylate (PMMA) to PMMA in
psi (MPa) 849

Tables xxxix
Table 18.38 Shear strength of polyethylene terephthalate (PET) to PET in psi (MPa) 850
Table 18.39 Shear strength of polyetheretherketone (PEEK) to PEEK in psi (MPa) 850
Table 18.40 Shear strength of liquid crystal polymer (LCP) to LCP in psi (MPa) 851
Table 18.41 Shear strength of fluoroplastic to fluoroplastic in psi (MPa) 851
Table 18.42 Guide relating molded wall thicknesses to insert diameters (in [mm]) 862
Table 18.43 Examples of welding methods versus tensile-strength retention 865
Table 18.44 Examples of welding characteristics 865
Table 18.45 Examples of ultrasonic welding applications 866
Table 18.46 Comparison of a few welding methods 866
Table 18.47 Comparing welding of different plastics, each to itself 867
Table 18.48 Economic guide to a few welding processes 868
Table 18.49 Tensile strength of hot-plate welding PP copolymerized with ethylene
pipe 870
Table 18.50 Impact and tensile strength of hot-plate welding high-density
polyethylene (HDPE) 870
Table 18.51 Tensile strength of different hot-plate welds of PP copolymerized with
ethylene pipe 870
Table 18.52 Tensile strength of hot-plate weldingABS 871
Table 18.53 Properties of vibration welds of PC to itself and other plastics 877
Table 18.54 Properties of vibration welds of PC/ABS to itself and other plastics 877
Table 18.55 Properties of vibration welds of PC/polybutylene terephthalate (PBT) to
itself and to PC 878
Table 18.56 Properties of vibration welds ofABS to itself and other plastics 878
Table 18.57 Properties of vibration welds of acrylonitrile-styrene-acrylate (ASA) to
itself 879
Table 18.58 Properties of vibration welds of PS-modified PPE/PA to itself and other
plastics 879
Table 18.59 Properties of vibration welds of modified polypropylene oxide (PPO) to
itself and other plastics 880
Table 18.60 Properties of vibration welds of PBT to itself and other plastics 880
Table 18.61 Example of a boss-hole design for the use of ultrasonically installed
inserts using styrene maleic anhydride copolymer 884
Table 18.62 Optimum ultrasonic welding conditions for impact-modified PET-PC
blend 884
Table 18.63 Weld strength of ultrasonic bonds of medical plastics; three letters in
each box represent bonds subjected to no sterilization, ethylene-oxide
sterilization, and gamma-radiation sterilization, respectively 885
Table 18.64 Guide to bonding plastic to plastic via induction welding 886
Table 18.65 Properties of radio-frequency welding of flexible PVC to itself and other
plastics 888

xl Tables
Table 18.66 Properties of radio-frequency welding of rigid PVC to itself and other
plastics 889
Table 18.67 Properties of radio-frequency welding of aromatic polyester PUR to
itself and other plastics 889
Table 18.68 Properties of laser-welded PE joints 892
Table 18.69 Properties of laser-welded PP joints 892
Table 18.70 Examples of machining operations 893
Table 18.71 Examples of finishing operations 893
Table 18.72 Examples of supplementary machining operations 894
Table 18.73 Guide to single-point box-tool machining (chapter 17 reviews tool
materials) 898
Table 18.74 Guide to turning, cutoff, and form-tool machining 899
Table 18.75 Guide to drilling 900
Table 18.76 Guide to end milling: Slotting machining 901
Table 18.77 Guide to end milling: Peripheral machining 902
Table 18.78 Guide to side and slot milling arbor-mounted cutter machining 903
Table 18.79 Guide to face-milling machining 904
Table 18.80 Guide to power band sawing 905
Table 18.81 Guide to tappingTPs andTS plastics 905
Table 18.82 Guide to reamingTPs andTS plastics 906
Table 18.83 Guide to standard tolerances for punched holes and slots in sheet stock 907
Table 18.84 NEMA guide to standard tolerances for punched holes and slots in high-
pressure composite laminated grades of sheet stock, rods, and tubes 908
Table 18.85 Guide to cutting equipment capabilities 908
Table 18.86 Guide to drill geometry 908
Table 18.87 Examples of cutting-tool geometries 912
Table 18.88 Guide for drilling 1/2 to 3/8 in holes inTPs 919

AA acrylic acid
AAE AmericanAssociation of Engineers
AAES AmericanAssociation of Engineering
Societies
ABR polyacrylate
ABS acrylontrile-butadiene-styrene
AC alternating current
ACS American Chemical Society
ACTC Advanced CompositeTechnology
Consortium
ad adhesive
ADC allyl diglycol carbonate (also CR-39)
AFCMA Aluminum Foil Container Manufactur-
ers’Association
AFMA American Furniture Manufacturers’
Association
AFML Air Force Material Laboratory
AFPA American Forest and PaperAssociation
AFPR Association of Foam Packaging Recyclers
AGMA American Gear Manufacturers’Association
AIAA American Institute ofAeronautics and
Astronauts
AIChE American Institute of Chemical Engineers
AIMCAL Association of Industrial Metallizers,
Coaters, and Laminators
AISI American Iron and Steel Institute
AMBA American Mold Builders Association
AMC alkyd molding compound
AN acrylonitrile
ANSI American National Standards Institute
ANTEC AnnualTechnical Conference (of the Soci-
ety of the Plastic Engineers)
APC American Plastics Council
APET amorphous polyethylene terephthalate
APF Association of Plastics Fabricators
API American Paper Institute
APME Association of Plastics Manufacturers in
Europe
APPR Association of Post-Consumer Plastics
Recyclers
AQL acceptable quality level
AR aramid fiber; aspect ratio
ARP advanced reinforced plastic
ASA acrylonitrile-styrene-acrylate
ASCII american standard code for information
exchange
ASM American Society for Metals
Abbreviations

xlii Abbreviations
ASME American Society of Mechanical Engineers
ASNDT American Society for Non-Destructive
Testing
ASQC American Society for Quality Control
ASTM American Society forTesting Materials
atm atmosphere
bbl barrel
BFRL Building and Fire Research Laboratory
Bhn Brinell hardness number
BM blow molding
BMC bulk molding compound
BO biaxially oriented
BOPP biaxially oriented polypropylene
BR polybutadiene
Btu British thermal unit
buna polybutadiene
butyl butyl rubber
CA cellulose acetate
CAB cellulose acetate butyrate
CaCO3 calcium carbonate (lime)
CAD computer-aided design
CAE computer-aided engineering
CAM computer-aided manufacturing
CAMPUS computer-aided material preselection
by uniform standards
CAN cellulose acetate nitrate
CAP cellulose acetate propionate
CAS Chemical Abstract Service (a division of the
American Chemical Society)
CAT computer-aided testing
CBA chemical blowing agent
CCA cellular cellulose acetate
CCV Chrysler composites vehicle
CEM Consorzio Export Mouldex (Italian)
CFA Composites FabricatorsAssociation
CFC chlorofluorocarbon
CFE polychlorotrifluoroethylene
CIM ceramic injection molding; computer inte-
grated manufacturing
CLTE coefficient of linear thermal expansion
CM compression molding
CMA Chemical Manufacturers’Association
CMRA Chemical Marketing Research Association
CN cellulose nitrate (celluloid)
CNC computer numerically controlled
CP Canadian Plastics
CPE chlorinated polyethylene
CPET crystallized polyethylene terephthalate
CPI Canadian Plastics Institute
cpm cycles/minute
CPVC chlorinated polyvinyl chloride
CR chloroprene rubber; compression ratio
CR-39 allyl diglycol carbonate
CRP carbon reinforced plastics
CRT cathode ray tube
CSM chlorosulfonyl polyethylene
CTFE chlorotrifluorethylene
DAP diallyl phthalate
dB decibel
DC direct current
DEHP diethylhexyl phthalate
den denier
DGA differential gravimetric analysis
DINP diisononyl phthalate
DMA dynamic mechanical analysis
DMC dough molding compound
DN Design News publication
DOE Design of Experments
DSC differential scanning calorimeter
DSD Duales System Deutschland (German Recy-
cling System)
DSQ German Society for Quality
DTA differential thermal analysis
DTGA differential thermogravimetric analysis
DTMA dynamic thermomechanical analysis
DTUL deflection temperature under load
DV devolatilization
DVR design value resource; dimensional velocity
research; Druckverformungsrest (German

Abbreviations xliii
compression set); dynamic value research;
dynamic velocity ratio
E modulus of elasticity;Young’s modulus
EBM extrusion blow molding
Ec modulus, creep (apparent)
EC ethyl cellulose
ECTFE polyethylene-chlorotrifluoroethylene
EDM electrical discharge machining
E/E electronic/electrical
EEC European Economic Community
EI modulus × moment of inertia (equals stiffness)
EMI electromagnetic interference
EO ethylene oxide (also EtO)
EOT ethylene ether polysulfide
EP ethylene-propylene
EPA Environmental ProtectionAgency
EPDM ethylene-propylene diene monomer
EPM ethylene-propylene fluorinated
EPP expandable polypropylene
EPR ethylene-propylene rubber
EPS expandable polystyrene
Er modulus, relaxation
Es modulus, secant
ESC environmental stress cracking
ESCR environmental stress cracking resistance
ESD electrostatic safe discharge
ET ethylene polysulfide
ETFE ethylene terafluoroethylene
ETO ethylene oxide
EU entropy unit; European Union
EUPC EuropeanAssociation of Plastics Converters
EUPE European Union of Packaging and
Environment
EUROMAP Eu^ropean Committee of Machine
Manufacturers for the Rubber and Plastics
Industries (Zurich, Switzerland)
EVA ethylene-vinyl acetate
E/VAC ethylene/vinyl acetate copolymer
EVAL ethylene-vinyl alcohol copolymer (trade-
name for EVOH)
EVE ethylene-vinyl ether
EVOH ethylene-vinyl alcohol copolymer (or
EVAL)
EX extrusion
F coefficient of friction; Farad; force
FALLO follow all opportunities
FDA Food and Drug Administration
FEA finite element analysis
FEP fluorinated ethylene-propylene
FFS form, fill, and seal
FLC fuzzy logic control
FMCT fusible metal core technology
FPC flexible printed circuit
fpm feet per minute
FRCA Fire Retardant Chemicals Association
FRP fiber reinforced plastic
FRTP fiber reinforced thermoplastic
FRTS fiber reinforced thermoset
FS fluorosilicone
FTIR Fourier transformation infrared
FV frictional force × velocity
G gravity; shear modulus (modulus of rigidity);
torsional modulus
GAIM gas-assisted injection molding
gal gallon
GB gigabyte (billion bytes)
GD&T geometric dimensioning and tolerancing
GDP gross domestic product
GFRP glass fiber reinforced plastic
GMP good manufacturing practice
GNP gross national product
GP general purpose
GPa giga-Pascal
GPC gel permeation chromatography
gpd grams per denier
gpm gallons per minute
GPPS general purpose polystyrene
GRP glass reinforced plastic
GR-S polybutadiene-styrene
GSC gas solid chromatography

xliv Abbreviations
H hysteresis; hydrogen
HA hydroxyapatite
HAF high-abrasion furnace
HB Brinell hardness number
HCFC hydrochlorofluorocarbon
HCl hydrogen chloride
HDPE high-density polyethylene (also PE-HD)
HDT heat deflection temperature
HIPS high-impact polystyrene
HMC high-strength molding compound
HMW-HDPE high molecular weight–high density
polyethylene
H-P Hagen-Poiseuille
HPLC high-pressure liquid chromatography
HPM hot pressure molding
HTS high-temperature superconductor
Hz Hertz (cycles)
I integral; moment of inertia
IB isobutylene
IBC internal bubble cooling
IBM injection blow molding; International Busi-
ness Machines
IC Industrial Computing publication
ICM injection-compression molding
ID internal diameter
IEC International Electrochemical Commission
IEEE Institute of Electrical and Electronics
Engineers
IGA isothermal gravimetric analysis
IGC inverse gas chromatography
IIE Institute of Industrial Engineers
IM injection molding
IMM injection molding machine
IMPS impact polystyrene
I/O input/output
ipm inch per minute
ips inch per second
IR synthetic polyisoprene (synthetic natural
rubber)
ISA Instrumentation, Systems, andAutomation
ISO International Standardization Organiza-
tion or International Organization for
Standardization
IT information technology
IUPAC International Union of Pure and Applied
Chemistry
IV intrinsic viscosity
IVD in vitro diagnostic
J joule
JIS Japanese Industrial Standard
JIT just-in-time
JIT just-in-tolerance
Jp polar moment of inertia
JSR Japanese SBR
JSW Japan SteelWorks
JUSE Japanese Union of Science and Engineering
JWTE JapanWeatheringTest Center
K bulk modulus of elasticity; coefficient of thermal
conductivity; Kelvin; Kunststoffe (plastic in
German)
kb kilobyte (1000 bytes)
kc kilocycle
kg kilogram
KISS keep it short and simple
Km kilometer
kPa kilo-Pascal
ksi thousand pounds per square inch (psi × 103)
lbf pound-force
LC liquid chromatography
LCP liquid crystal polymer
L/D length-to-diameter (ratio)
LDPE low-density polyethylene (PE-LD)
LIM liquid impingement molding; liquid injection
molding
LLDPE linear low-density polyethylene (also
PE-LLD)
LMDPE linear medium density polyethylene
LOX liquid oxygen
LPM low-pressure molding
m matrix; metallocene (catalyst); meter

Abbreviations xlv
mµ micromillimeter; millicron; 0.000001 mm
µm micrometer
MA maleic anhydride
MAD mean absolute deviation; molding area
diagram
Mb bending moment
MBTS benzothiazyl disulfide
MD machine direction; mean deviation
MD&DI Medical Device and Diagnostic Industry
MDI methane diisocyanate
MDPE medium density polyethylene
Me metallocene catalyst
MF melamine formaldehyde
MFI melt flow index
mHDPE metallocene high-density polyethylene
MI melt index
MIM metal powder injection molding
MIPS medium impact polystyrene
MIT Massachusetts Institute ofTechnology
mLLDPE metallocene catalyst linear low-density
polyethylene
MMP multimaterial molding or multimaterial
multiprocess
MPa mega-Pascal
MRPMA Malaysian Rubber Products Manufactur-
ers’Association
Msi million pounds per square inch (psi × 106)
MSW municipal solid waste
MVD molding volume diagram
MVT moisture vapor transmission
MW molecular weight
MWD molecular weight distribution
MWR molding with rotation
N Newton (force)
NACE NationalAssociation of Corrosion
Engineers
NACO NationalAssociation of CAD/CAM
Operation
NAGS NorthAmerica Geosynthetics Society
NASA NationalAeronautics SpaceAdministration
NBR butadiene acrylontrile
NBS National Bureau of Standards (since 1980
renamed the National Institute Standards and
Technology or NIST)
NC numerical control
NCP National Certification in Plastics
NDE nondestructive evaluation
NDI nondestructive inspection
NDT nondestructive testing
NEAT nothing else added to it
NEMA National Electrical Manufacturers’
Association
NEN Dutch standard
NFPA National Fire ProtectionAssociation
NISO National Information Standards
Organization
NIST National Institute of Standards and
Technology
nm nanometer
NOS not otherwise specified
NPCM National Plastics Center and Museum
NPE National Plastics Exhibition
NPFC National Publications and Forms Center
(US government)
NR natural rubber (polyisoprene)
NSC National Safety Council
NTMA NationalTool and Machining Association
NWPCA NationalWooden Pallet and Container
Association
OD outside diameter
OEM original equipment manufacturer
OPET oriented polyethylene terephthalate
OPS oriented polystyrene
OSHA Occupational Safety and Health
Administration
P load; poise; pressure
Pa Pascal
PA polyamide (nylon)
PAI polyamide-imide
PAN polyacrylonitrile

xlvi Abbreviations
PB polybutylene
PBA physical blowing agent
PBNA phenyl-β-naphthylamine
PBT polybutylene terephthalate
PC permeability coefficient; personal computer;
plastic composite; plastic compounding;
plastic-concrete; polycarbonate; printed cir-
cuit; process control; programmable circuit;
programmable controller
PCB printed circuit board
pcf pounds per cubic foot
PCFC polychlorofluorocarbon
PDFM Plastics Distributors and Fabricators
Magazine
PE plastic engineer; polyethylene (UK polythene);
professional engineer
PEEK polyetheretherketone
PEI polyetherimide
PEK polyetherketone
PEN polyethylene naphthalate
PES polyether sulfone
PET polyethylene terephthalate
PETG polyethylene terephthalate glycol
PEX polyethylene crosslinked pipe
PF phenol formaldehyde
PFA perfluoroalkoxy (copolymer of tetrafluoro-
ethylene and perfluorovinylethers)
PFBA polyperfluorobutyl acrylate
phr parts per hundred of rubber
PI polyimide
PIA Plastics Institute ofAmerica
PID proportional-integral-differential
PIM powder injection molding
PLASTEC PlasticsTechnical Evaluation Center
(US Army)
PLC programmable logic controller
PMMA Plastics Molders and Manufacturers’Asso-
ciation (of SME); polymethyl methacrylate
(acrylic)
PMMI Packaging Machinery Manufacturers’
Institute
PO polyolefin
POE polyolefin elastomer
POM polyoxymethylene or polyacetal (acetal)
PP polypropylene
PPA polyphthalamide
ppb parts per billion
PPC polypropylene chlorinated
PPE polyphenylene ether
pph parts per hundred
ppm parts per million
PPO polyphenylene oxide
PPS polyphenylene sulfide
PPSF polyphenylsulfone
PPSU polyphenylene sulphone
PS polystyrene
PSB polystyrene butadiene rubber (GR-S, SBR)
PS-F polystyrene-foam
psf pounds per square foot
PSF polysulphone
psi pounds per square inch
psia pounds per square inch, absolute
psid pounds per square inch, differential
psig pounds per square inch, gauge (above atmo-
spheric pressure)
PSU polysulfone
PTFE polytetrafluoroethylene (orTFE)
PUR polyurethane (also PU, UP)
P-V pressure-volume (also PV)
PVA polyvinyl alcohol
PVAC polyvinyl acetate
PVB polyvinyl butyral
PVC polyvinyl chloride
PVD physical vapor deposition
PVDA polyvinylidene acetate
PVdC polyvinylidene chloride
PVDF polyvinylidene fluoride
PVF polyvinyl fluoride
PVP polyvinyl pyrrolidone

Abbreviations xlvii
PVT pressure-volume-temperature (also P-V-T or
pvT)
PW Plastics World magazine
QA quality assurance
QC quality control
QMC quick mold change
QPL qualified products list
QSR quality system regulation
R Reynolds number; Rockwell (hardness)
rad Quantity of ionizing radiation that results
in the absorption of 100 ergs of energy per
gram of irradiated material.
radome radar dome
RAPRA Rubber and Plastics ResearchAssociation
RC Rockwell C (Rc)
RFI radio frequency interference
RH relative humidity
RIM reaction injection molding
RM rotational molding
RMA Rubber Manufacturers’Association
RMS root mean square
ROI return on investment
RP rapid prototyping; reinforced plastic
RPA Rapid PrototypingAssociation (of SME)
rpm revolutions per minute
RRIM reinforced reaction injection molding
RT rapid tooling; room temperature
RTM resin transfer molding
RTP reinforced thermoplastic
RTS reinforced thermoset
RTV room temperature vulcanization
RV recreational vehicle
Rx radiation curing
SAE Society ofAutomotive Engineers
SAMPE Society for theAdvancement of Material
and Process Engineering
SAN styrene acrylonitrile
SBR styrene-butadiene rubber
SCT soluble core technology
SDM standard deviation measurement
SES Standards Engineering Society
SF safety factor; short fiber; structural foam
s.g. specific gravity
SI International System of Units
SIC Standard Industrial Classification
SMC sheet molding compound
SMCAA Sheet Molding Compound Automotive
Alliance
SME Society of Manufacturing Engineers
S-N stress-number of cycles
SN synthetic natural rubber
SNMP simple network management protocol
SPC statistical process control
SPE Society of the Plastics Engineers
SPI Society of the Plastics Industry
sPS syndiotactic polystyrene
sp. vol. specific volume
SRI Standards Research Institute (ASTM)
S-S stress-strain
STP SpecialTechnical Publication (ASTM); stan-
dard temperature and pressure
t thickness
T temperature; time; torque (orTt)
TAC triallylcyanurate
T/C thermocouple
TCM technical cost modeling
TD transverse direction
TDI toluene diisocyanate
TF thermoforming
TFS thermoform-fill-seal
Tg glass transition temperature
TGA thermogravimetric analysis
TGI thermogravimetric index
TIR tooling indicator runout
T-LCP thermotropic liquid crystal polymer
TMA thermomechanical analysis;Tooling and
Manufacturing Association (formerlyTDI);
Toy Manufacturers of America
torr mm mercury (mmHg); unit of pressure equal
to 1/760th of an atmosphere

xlviii Abbreviations
TP thermoplastic
TPE thermoplastic elastomer
TPO thermoplastic olefin
TPU thermoplastic polyurethane
TPV thermoplastic vulcanizate
Ts tensile strength; thermoset
TS twin screw
TSC thermal stress cracking
TSE thermoset elastomer
TX thixotropic
TXM thixotropic metal slurry molding
UA urea, unsaturated
UD unidirectional
UF urea formaldehyde
UHMWPE ultra-high molecular weight polyethyl-
ene (also PE-UHMW)
UL Underwriters Laboratories
UP unsaturated polyester (alsoTS polyester)
UPVC unplasticized polyvinyl chloride
UR urethane (also PUR, PU)
URP unreinforced plastic
UV ultraviolet
UVCA ultra-violet-light-curable-cyanoacrylate
V vacuum; velocity; volt
VA value analysis
VCM vinyl chloride monomer
VLDPE very low-density polyethylene
VOC volatile organic compound
vol% percentage by volume
w width
W watt
W/D weight-to-displacement volume (boat
hull)
WIT water-assist injection molding technology
WMMA Wood Machinery Manufacturers of
America
WP&RT World Plastics and RubberTechnology
magazine
WPC wood-plastic composite
wt% percentage by weight
WVT water vapor transmission
XL cross-linked
XLPE cross-linked polyethylene
XPS expandable polystyrene
YPE yield point elongation
Z-twist twisting fiber direction

Undertaking the development through to the completion of the Plastics Technology Handbook required
the assistance of key individuals and groups.The indispensable guidance and professionalism of our
publisher, Joel Stein, and his team at Momentum Press was critical throughout this enormous proj-
ect.The coeditors, Nick R. Schott, Professor Emeritus of the University of Massachusetts Lowell
Plastics Engineering Department, and Marlene G. Rosato, President of Gander International Inc.,
were instrumental to the data, information, and analysis coordination of the eighteen chapters of
the handbook. A special thank you is graciously extended to Napoleao Neto of Alphagraphics for
the organization and layout of the numerous figure and table graphics central to the core handbook
theme. Finally, a great debt is owed to the extensive technology resources of the Plastics Institute
of America at the University of Massachusetts Lowell and its Executive Director, Professor Aldo
M. Crugnola.
Dr. DonaldV. Rosato, Coeditor and President, PlastiSource, Inc.
Acknowledgments

This book, as a two-volume set, offers a simplified, practical, and innovative approach to under-
standing the design and manufacture of products in the world of plastics. Its unique review will
expand and enhance your knowledge of plastic technology by defining and focusing on past, cur-
rent, and future technical trends. Plastics behavior is presented to enhance one’s capability when
fabricating products to meet performance requirements, reduce costs, and generally be profitable.
Important aspects are also presented to help the reader gain understanding of the advantages of
different materials and product shapes.The information provided is concise and comprehensive.
Prepared with the plastics technologist in mind, this book will be useful to many others.The
practical and scientific information contained in this book is of value to both the novice, including
trainees and students, and the most experienced fabricators, designers, and engineering person-
nel wishing to extend their knowledge and capability in plastics manufacturing including related
parameters that influence the behavior and characteristics of plastics.The toolmaker (who makes
molds, dies, etc.), fabricator, designer, plant manager, material supplier, equipment supplier, test-
ing and quality control personnel, cost estimator, accountant, sales and marketing personnel, new
venture type, buyer, vendor, educator/trainer, workshop leader, librarian, industry information
provider, lawyer, and consultant can all benefit from this book.The intent is to provide a review
of the many aspects of plastics that range from the elementary to the practical to the advanced and
more theoretical approaches. People with different interests can focus on and interrelate across
subjects in order to expand their knowledge within the world of plastics.
Over 20000 subjects covering useful pertinent information are reviewed in different chapters
contained in the two volumes of this book, as summarized in the expanded table of contents and
index. Subjects include reviews on materials, processes, product designs, and so on. From a prag-
matic standpoint, any theoretical aspect that is presented has been prepared so that the practical
person will understand it and put it to use.The theorist in turn will gain an insight into the practical
Preface

lii Preface
limitations that exist in plastics as they exist in other materials such as steel, wood, and so on.There
is no material that is“perfect.”The two volumes of this book together contain 1800-plus figures and
1400-plus tables providing extensive details to supplement the different subjects.
In working with any material (plastics, metal, wood, etc.), it is important to know its behavior
in order to maximize product performance relative to cost and efficiency. Examples of different
plastic materials and associated products are reviewed with their behavior patterns. Applications
span toys, medical devices, cars, boats, underwater devices, containers, springs, pipes, buildings,
aircraft, and spacecraft.The reader’s product to be designed or fabricated, or both, can be related
directly or indirectly to products reviewed in this book. Important are behaviors associated with
and interrelated with the many different plastics materials (thermoplastics [TPs], thermosets [TSs],
elastomers, reinforced plastics) and the many fabricating processes (extrusion, injection molding,
blow molding, forming, foaming, reaction injection molding, and rotational molding). They are
presented so that the technical or nontechnical reader can readily understand the interrelationships
of materials to processes.
This book has been prepared with the awareness that its usefulness will depend on its simplicity
and its ability to provide essential information.An endless amount of data exists worldwide for the
many plastic materials, which total about 35000 different types. Unfortunately, as with other mate-
rials, a single plastic material that will meet all performance requirements does not exist. However,
more so than with any other materials, there is a plastic that can be used to meet practically any
product requirement. Examples are provided of different plastic products relative to critical factors
ranging from meeting performance requirements in different environments to reducing costs and
targeting for zero defects.These reviews span products that are small to large and of shapes that are
simple to complex.The data included provide examples that span what is commercially available.
For instance, static physical properties (tensile, flexural, etc.), dynamic physical properties (creep,
fatigue, impact, etc.), chemical properties, and so on, can range from near zero to extremely high
values, with some having the highest of any material.These plastics can be applied in different envi-
ronments ranging from below and on the earth’s surface to outer space.
Pitfalls to be avoided are reviewed in this book.When qualified people recognize the poten-
tial problems, these problems can be designed around or eliminated so that they do not affect
the product’s performance. In this way, costly pitfalls that result in poor product performance or
failure can be reduced or eliminated. Potential problems or failures are reviewed, with solutions
also presented.This failure-and-solution review will enhance the intuitive skills of people new to
plastics as well as those who are already working in plastics. Plastic materials have been produced
worldwide over many years for use in the design and fabrication of all kinds of plastic products.To
profitably and successfully meet high-quality, consistency, and long-life standards, all that is needed
is to understand the behavior of plastics and to apply these behaviors properly.
Patents or trademarks may cover certain of the materials, products, or processes presented.
They are discussed for information purposes only and no authorization to use these patents or
trademarks is given or implied. Likewise, the use of general descriptive names, proprietary names,
trade names, commercial designations, and so on does not in any way imply that they may be used

Preface liii
freely.While the information presented represents useful information that can be studied or ana-
lyzed and is believed to be true and accurate, neither the authors, contributors, reviewers, nor
the publisher can accept any legal responsibility for any errors, omissions, inaccuracies, or other
factors. Information is provided without warranty of any kind. No representation as to accuracy,
usability, or results should be inferred.
Preparation for this book drew on information from participating industry personnel, global
industry and trade associations, and the authors’ worldwide personal, industrial, and teaching
experiences.
DON & MARLENE ROSATOAND NICK SCHOTT, 2011

Chapter 10
Coating
OVERVIEW
Different resin (also called polymer and plastic) coating systems have widespread industrial and
commercial applications.They can be applied by direct contact of a liquid coating with the substrate
to deposition using an atomization process. Direct methods include brushing, roller coating, dip-
ping, flow coating, and electrodeposition. Deposition methods include conventional spray, airless
spray, hot spray, and electrostatic spray. Extrusion coating is one of the principal methods (chap-
ter 5). Coating via calenders is another important method (chapter 9). Coatings are applied in
molds during injection molding (chapter 4).There is film coating applied during thermoforming
(chapter 7; 477). Other fabricating processes incorporate coatings.
Coating resins are used for coating materials in practically all the markets that include electric/
electronic, packaging, building, household and industrial appliances, transportation, marine, medi-
cal, and clothing (chapter 20). Continual consumer demands for more attractive and styled packages
have caused plastic material suppliers to develop new coatings with high decorative and visual appeal.
Selection of the plastic to be used usually depends on decorative and environmental requirements.
Coated containers include beer cans, liquid-containing tanks, and electronics packages.
Resin coatings are used extensively for corrosion protection of metals in different environ-
ments such as inside and outside of buildings,chemical plants,marine products,and so on.Residual
stresses can be present in these coatings. For example, solvent loss and, in the case of thermosets
(TSs), the curing process, causes shrinkage of the coating.When it is applied to a stiff substrate, the
shrinkage in the plane of the coating is resisted and biaxial tensile residual stresses form. If applica-
tion of the coating is made at a temperature different from the subsequent service temperature,
there will be further residual stresses that result from differential thermal expansion of the coating
and substrate (chapter 21).

2 Plastics Technology Handbook—Volume 2
Resins continue to be the backbone in the coating industry because almost all coatings are com-
posed of resin materials.The most widely used are based on polyethylenes, polypropylenes, vinyls,
alkyds, acrylics, urea-melamine, styrenes, epoxies, phenolics, fluoroplastics, and silicones (chapter
2).The resins are used alone or are cross-blended with other resins.Table 10.1 lists different coat-
ings that include those in solvent systems or those with certain resins, such as vinyl in different
forms of organic media dispersions.These higher solids content dispersions can be in nonvolatile
(plastisol) suspension or in volatile (organosol) suspension (chapter 16).Table 10.2 reviews coating
compounds with applications that are mainly used in Europe.
The alkyds are used mainly (but extensively) in coatings.Their ease of application and low cost
makes them useful. Epoxy systems continue to find more applications because they have inherently
desirable characteristics such as the ease with which they adhere to a substrate. Fluorocarbons can
be vacuum deposited on various metals and plastics containers, which provides the expected envi-
ronmental resistances, such as to water and salt spray.The polyamides are used to protect metal
containers from weathering and chemical corrosion.The silicones are considered for use when heat
resistance is part of the coating requirement. Urethane coatings are generally baked so to provide
maximum protection in such applications as electrical or outdoor-use packages. Properties of the
different plastics are reviewed in chapter 2.
The vinyls appear to be in a class of their own, because they can be applied by many different
techniques to metal and other parts before fabrication into various shapes.They are tough, flexible,
low in cost, and resistant to normal environments.They also provide good adhesion.
Fuel-resistant coatings are used to help the handling of gasoline and fuel oil in plastic or steel
tanks. Coating systems employed in the past were only partially successful in protecting the steel
interior of the tanks.They often cracked, peeled, or softened and thus exposed the steel to corro-
sion. Excellent coatings have now been developed and used successfully.
Growth has been steady and reliable, so that rational and economic coating production is no
longer regarded, as was the case until relatively recently, as an art or craft based solely on empirical
results. For example, coatings are being applied to plastic and metal containers to provide improve-
ments in appearance, resistance to environmental breakdown, and easy handling.
Resins are employed in the manufacture of a large number of coating compounds that are used
to cover the surfaces of many materials from paper to metal to concrete. Many plastics are used as
coating materials, including paints, varnishes, enamels, and materials of various resin-coating com-
positions that are applied to fabrics,paper,plastic,cardboard,leather,metal,and wood.As has been
noted, there are a number of methods of applying plastic coatings, including the major processes
such as extrusion and injection molding.When they are in a liquid or latex form, such as in paint or
adhesives, they may be applied by brushing, spraying, dipping, and so on. In coating operations, the
base material, such as paper, is run through a machine that melts solid plastic granules and spreads
them evenly across the surface of the base material.As the hot plastic cools,it becomes bonded,like
an adhesive, to its base.
The products of the coating industry are essential for the protection and decoration of the
majority of manufactured goods and architectural or industrial structures that characterize our

Coating 3
Table 10.1 Examples of different coating materials

Table 10.1 Examples of different coating materials (continued)

Coating 5
Table 10.1 Examples of different coating materials (continued)

complex material civilization. The protective function includes resistance to air, water, organic
liquids, and aggressive chemicals such as acids and alkalis, together with improved superficial
mechanical properties such as greater hardness and abrasion resistance.The decorative effect may
be obtained through color, gloss, or texture or combinations of these properties.
In the case of many surfaces such as walls or floors, or objects such as interior fittings, furniture
and other articles, the surface coating can fulfill hygienic requirements.The surface should not be
prone to collect dirt, bacteria, and other impurities. It should be easy to clean with common clean-
ing agents. In certain cases special qualities are required of the surface coating. For example, special
Table 10.2 Important coating compounds and applications

Coating 7
Table 10.2 Important coating compounds and applications (continued)

qualities are needed in road-marking paints, safety-marking paints, paints used in factories, and
paints that render a surface either a good or a poor conductor of electricity.
Metals surfaces may be coated to improve their workability in mechanical processing.Substrates
protected from different environmental conditions include the metals (steel, zinc, aluminum, and
copper), inorganic materials (plaster, concrete, and asbestos), and organic materials (wood, wall-
board, wallpaper, and plastics). Different technical developments have occurred in the coating
industry, which permit the use of a variety of raw materials. It is possible to formulate surface
coatings that are suitable for each and every kind of material. In many cases a number of different
coating systems may come into consideration for painting a particular substrate. In almost all cases
a painting problem may be solved in a variety of ways.
Resins are employed in the manufacture of most of the coating compounds.A significant amount
of all the resins produced are consumed as coating materials in the various forms. Based on the rela-
tively low capital investments in coating-producing plants,the return on investment is excellent when
compared to that of other industries. Net profit margins continue to be in the 6% of sales bracket.At
the present,profit for the major type products has been principally due to improved plant manufactur-
ing efficiency.Today’s production is by batch process, automation, and mass-production techniques,
depending on the quantity of the product and the manufacturing lot’s size.
Different Coating Aspect
Coating materials and coating techniques can be distinguished and systematized in various ways
(374).The fundamental principles of common coating systems are
1. Physical drying.A solid surface film is formed after the evaporation of water or organic
solvents.
2. Physico-chemical drying/curing. Polycondensation or polyaddition are combined with
evaporation of organic solvents.
3. Chemical curing. Solvents, such as styrene or acrylic monomers, react with the curing
system.
The actual effects depend on the surrounding conditions and the coating system’s ingredients,
such as solvents. Solvents contribute many essential properties to coating systems. Solvents can
improve technical factors such as application or surface properties.They also bring negative quali-
ties to coating materials, especially with respect to environmental conditions (e.g., toxic effects of
emitted organic solvents).
Technical application techniques for coatings can be considered in various ways.The stability
and durability of coating is essential. Coatings that have normal wear-and-tear requirements are
based mainly on oils and aldehyde resins. Higher durability or stability can be achieved by the use
of one of the following one-or two-component systems.

Coating 9
Some examples of one-component systems are bituminous material, chlorinated rubber, polyvinyl
chloride (PVC), polyacrylic resin, polyethylene, saturated polyester, and polyamide. Some examples of
two-component systems are epoxy resin,polyurethane (PUR),and mixtures of reactive resins and tar.
Table 10.3 gives a survey of the performance of different coating materials and an assessment
of various environmental factors.
The following are examples of architectural concrete surface coatings.According to DIN 1045
(chapter 22) concrete must be protected against aggressive substances if the chemical attack is
severe and long-term.These are the requirements:
Table 10.3 Environmental performance of some coating materials

1. Good adhesion
2. Waterproof and resistant to aggressive substances and resistant to the alkalinity of the
concrete
3. Deformable
To realize these requirements, technical solutions such as surface treatments or paint coatings
based on thermoplastic (TP) substances can be applied.
Protective coatings based on resins are used in construction with and without fillers and with
or without fiber reinforcing materials (chapter 15).The following techniques are generally used:
1. Film-forming paint coatings (brushing, rolling, spraying)
2. Coating (filling, pouring)
During application, the coating materials are normally liquid and subsequently harden by evap-
oration of solvents or as a result of chemical reactions.The common coating systems for concrete
are listed inTable 10.4. Resins such as chlorinated rubbers, styrenes, and acrylics contain normally
40 wt% to 60 wt% solvents and form a thin film.Several coats must be applied.Reactive resins may
require little or no solvent.
Wet coatings for metals are listed inTable 10.5.
The drying process does not affect the chemical properties of binders if coatings are of physi-
cally drying type. After a solvent has evaporated, the resin molecules become intermeshed, thus
producing the desired coating properties.
In contrast to physical drying, binders based on reactive resins, such as epoxy resins, PURs, or
polyesters, consist of two components: liquid resin and curing agent.They are either mixed shortly
before the coat is applied or, in the case of a one-component system, applied as a slowly reacting
mixture.The setting reaction occurs at the surface of the coated material.The final products are
normally more resistant and more compact than products based on physically drying binders. Pre-
treatment of substrate is more critical for applications where chemically hardening products are
applied. Coatings can be more or less permeable to water vapor and oxygen. Damage to the metal
substrate can occur if water and oxygen reach the reactive surface simultaneously.This is normally
impossible if the coatings adhere well and the coated surface is continuous. The adhesion of the
coating also prevents penetration by harmful substances via diffusion processes. Adsorption and
chemical bonds enhance adhesion.
Other aspects of solvents contained in paint coatings and varnishes are available.The market
offers a wide spectrum of coating systems. Examples of common industrial coating materials are
listed inTable 10.6 and relevant aspects concerning application and environmental or health risks
are also included.Table 10.7 provides examples of release coating systems.

Coating 11
TERM AND PERFORMANCE INTRODUCTION
Coatings are generally identified as paints, varnishes, and lacquers. Other nomenclature includes
enamels, hot melts, plastisols, organosols, water-emulsion and solution finishes, nonaqueous dis-
persions, power coatings, masonry water repellents, polishes, magnetic tape coatings and overlays,
and so on.There are 100% resin coatings such as vinyl-coated fabrics or PUR floor coverings.The
most popular coatings, and the largest user of resins, are paints. Almost all the binders in paints,
varnishes, and lacquers are made up principally of resins (Table 10.1).
As reviewed in chapter 1, in the plastics industry, materials reviewed in this book can be identi-
fied by different terms such as polymer, plastic, resin, elastomer, and reinforced plastic (RP).They
are somewhat synonymous.Polymers,the basic ingredients in materials,can be defined as synthetic
or natural high-molecular-weight organic chemical compounds. Practically all of these polymers
Table 10.4 Survey of often-used coating systems for concrete
Table 10.5 Wet coating materials for metals

Table 10.6 Examples of coating materials including those containing solvents

Coating 13
Table 10.6 Examples of coating materials including those containing solvents (continued)

are compounded with other products (additives, fillers, reinforcements, etc.) to provide many dif-
ferent properties and processing capabilities or both;coatings are an important example of this kind
of polymer.Thus plastics is the correct term to use except in very few applications, where only the
polymer is used to fabricate products. However, in the coatings industry, the term resin, not plastics,
is the more commonly used term.
The term paint is often used nonspecifically to cover all the coating categories as though the
term was synonymous with coating; the terms are often used interchangeably. Paint coatings con-
sume by far the largest quantity of coating materials. However, the other coating processes are
important and useful.All these surface coatings represent a large segment of the plastic and chemi-
cal industries.
Paint
Paint consists of three main components, namely, the binder (resin), the pigment, and the solvent.
The function of the binder is to provide the forces that hold the film together (cohesive forces) and
that hold the film and the substrate together (adhesive forces; 374).
Table 10.7 Typical release coating systems and applications

Coating 15
The pigment is a fine powder whose function is to give a coating its desired color and hiding
properties. Pigments have a considerable influence on the consistency of the paint and in turn on its
application properties. Pigments are also of importance for the resistance of the coating to external
attack, in that they are partially responsible for such properties as hardening and resistance to abra-
sion and weathering.
The solvent is a volatile liquid whose function is to dissolve such binders as would be solid or
semisolid at normal temperature. In addition to these three basic components, modern coatings
may contain additives of various kinds. Examples are plasticizers, dryers, wetting agents, flattening
agents, and emulsifiers or other stabilizers.
The binder is the most important of the three main components and is always present in a
manufactured paint. It usually represents 40 wt% to 50 wt% of the paint. Many of the properties
of paints and related products are determined directly by the nature of the binder. For this reason
paints are often classified, and may even be named, according to the type of binder (Table 10.8).
Some binders are identified or arranged according to the type of drying. A differentiation is
made between physical and chemical drying in accordance with the way a coating forms, such as
the following:
1. Physical film formation (evaporation of solvent or of dispersion medium in the case
of lattices) that includes cellulosics (e.g., nitrocellulose and other esters of cellulose
and ethyl cellulose), vinyl resins (e.g., PVC, polyvinyl acetate [PVAc], and polyvinyl
acetal), acrylic ester resins, chlorinated rubber, and natural resins (e.g., shellac, rosin,
and rosin ester [ester gum]; bitumen [asphalt]; and glue)
2. Chemical film formation (convertible, oxidative drying) that includes drying oils,
linseed oil, tung oil, varnishes and oleoresins, and alkyd resins modified with drying oils
3. Cold curing that includes urea-formaldehyde resins, unsaturated polyester resins,
epoxy resins, amine-cured resins, and PUR resins
4. TS curing that includes short or medium oil length alkyd resins modified with
nondrying oils, water soluble alkyds, epoxy resins cross-linked with amino or
phenolic resins, water-soluble addition polymers cross-linked with amino or phenolic
resins, and acrylic resins cross-linked with amino or phenolic resins
Curing may be defined as a process in which drying occurs by a chemical reaction between the
molecules of the binder without the involvement of gaseous oxygen. If the reaction occurs at room
temperature the products are described inaccurately as “cold curing lacquers.” If temperatures of
70°C (158°F) or higher are necessary to cause rapid reaction, the materials are known as staving
or baking coatings. In view of the many different kinds of chemical reactions that are now used to
produce insoluble coatings, the term convertible coating is used.
A convertible coating may be defined as one in which the final form of the binder, in the film
differs chemically from the binder in the form in which it is applied.The conversion of one form to

the other may be achieved by the action of some component of the atmosphere, such as oxygen or
water; by heat; by radiation; by the use of catalysts; or by a reaction between two or more binder
components that are mixed just prior to application.
These reaction-type coatings provide films with greater hardness and chemical resistance than
those obtained by oxidative drying.
Water-Based Paint
Water-based, water-thinned, aqueous, and other terms are used to refer to paints that contain water.
Technically, three types exist: (1) latex or emulsion paints made with synthetic resins such acrylic,
PVAc, or butadiene-styrene; (2) water-soluble oils or alkyds; and (3) emulsified oils or alkyds.
Table 10.8 Example of paint and varnish coating compositions

Coating 17
Water-based paints using casein and emulsion oil paints containing alkyd resin and water were
first introduced just prior to World War II. Latex paints using butadiene-styrene followed after
WorldWar II.These were rubber-based paints that lacked ruggedness. In 1953 the acrylic emulsion
type of paint was introduced for indoor surfaces and outside masonry surfaces. By 1957, acrylic
emulsion types for exterior wood surfaces were on the market.
Water-based coatings continue to gleam in industry’s eye. Elimination of solvent fumes from
these systems reduces fire and explosion hazards, improves working conditions, and lowers insur-
ance rates.These systems are more expensive in terms of both the coating and the “paint booth
apparatus.”Water is more costly to evaporate,and its rate of evaporation is more difficult to control.
Varnish
The word varnish first appeared during the sixteenth century. It denoted a fluid mixture of amber
and oil, or more generally, of resin and oil.This latter meaning has survived to the present day.
Lacquer
Thetermlacquerisfrequentlyappliedtoalmostanycoatingcompositionthatdriessolely,andrapidly,
by evaporation of the solvent. It originally was almost exclusively associated with nitrocellulose-
based coatings. At the present time it generally refers to coatings that contain nitrocellulose or
possibly another cellulose derivative.
Solvent
The coating and other industrial processes include relying on the dissolution of raw materials
and subsequent removal of solvents by various drying processes.The formation of a solution
and the subsequent solvent removal depend on solvent transport phenomena that are deter-
mined by the properties of the solute and the properties of the solvent.A solvent is a material,
usually a liquid that has the power to dissolve another material and form a homogeneous
mixture known as a solution (Table 10.9). Most of these are toxic and flammable so exercise
caution when using them.
Knowledge of a solvent’s movement within the solid matrix by a diffusion process is essential
to design the technological processes. Many of the final properties, such as tribological proper-
ties; mechanical toughness; optical clarity; protection against corrosion adhesion to substrates and
reinforcing fillers; protective properties of clothing; quality of the coated surface; toxic residues;
morphology and residual stress; ingress of toxic substances; and chemical resistance depend not
only on the material chosen but also on the regimes of technological processes. For these reasons,
solvent transport phenomena are of interest to the modem industry (374).
Thin film coating and drying technology are the key technologies for manufacturing diverse
kinds of functional films, such as photographic films, adhesives, image media, magnetic media, and
lithium battery coating.Coating applied to a substrate as a liquid needs some degree of solidification

Table 10.9 Examples of solvents and their behaviors

Coating 19
Table 10.9 Examples of solvents and their behaviors (continued)
in order to be part of a final product.The degree of solidification can be low in the case of pressure-
sensitive adhesives (PSA), and it ranges to high in the case of dense metal oxides.The final structure
and properties of coating are greatly influenced by the drying conditions. Poorly chosen operating
conditions of drying cause unwanted internal gradients,phase separations,colloidal transformations
that lead to the wrong microstructure, inappropriate nonuniformities, and stress-related defects.
Solvent removal, or drying, which is part of the solidification process, is an important subject.
Typically, a coating solution consists of pigments, binders (plastics), and solvents.The solvents are
used to make the coating formulation soluble and to give the coating solution (or dispersion) the
rheology necessary for the application.The coating solution is deposited onto a substrate or web at
the coating station and is dried by passing through a series of separate ovens (zones).A substrate can
be an impermeable material such as plastic film or a permeable material in the case of paper coat-
ing.The dryer consists of ovens (zones) in which the temperature and velocity of air are controlled
independently.
Figure 10.1 is an example of an industrial coating and drying apparatus. A coated liquid is
deposited onto a substrate, which is unwound from a supply roll at the coating station and passes
through three separate ovens (dryer) in which the temperature and velocity of air are controlled
independently. Finally a take-up roll takes up the dried, coated substrate.The basics of the process
of drying are shown in Figure 10.2.
The air impinges on the coated and backside surface of the substrate through the nozzles and
sweeps away the solvent vapor from the coated surface. In the case of a single-sided impingement

dryer, the air impinges only on the coated surface.The coated film must be dry before reaching the
rewind station.The residence time of a coated substrate in the dryer is as short as several seconds
in the case of high-speed magnetic coating processes, and it ranges to as long as several minutes in a
case of lithium battery–coating processes.Finally,a take-up roll takes up the dried,coated substrate.
Free-radical polymerization is one of the most useful and lucrative fields of chemistry.In recent
years there has been a tremendous increase in research in this area, which was once considered a
mature technological field. Free-radical synthetic polymer chemistry is tolerant of diverse func-
tionality and can be performed in a wide range of media.
Figure 10.1 Example of industrial coating and drying apparatus.
Figure 10.2 The basic drying process and typical drying parameters.

Coating 21
Emulsion and suspension polymerizations have been important industrial processes for many
years. More recently, the “green” synthesis of resins has diversified from aqueous media to super-
critical fluids and the fluorous biphase.An enduring feature of the research literature on free-radical
polymerization has been studies into specific solvent effects. In many cases the influence of solvents
is small. However, it is becoming increasingly evident that solvent effects can be used to assist in
controlling the polymerization reaction, at both the macroscopic and the molecular levels (374).
PROPERTIES OF PLASTICS
Almost all the binders in paint, varnish, and lacquer coatings are composed of plastic materials.The
plastics are applied in one operation or built up during the drying processes.For example,the physical
and chemical properties of vinyl coatings have a direct relationship to the basic polymeric material.
The use of synthetic resins dates back to the turn of the twentieth century. Up untilWorldWar I they
were principally used as low-cost substitutes for natural resins.Since 1915 many different plastics that
offer many advantages compared with the natural resins have been used (Table 10.10).
The synthetic resins are less subject to variations in availability and consequently have more
stable costs. They may be produced to fairly close technical tolerances, while the natural resins
show wide variations in quality. More important, however, is the fact that the synthetic resins can
be varied in relation to the end use for which they are intended.
The major long-range trend in paints and related surface coatings is toward greater efficiency.
The target continues to be products with better environmental protection or decoration for longer
periods of time at lower total cost per square foot. Paints compete with a variety of other surfac-
ing materials, such as wallpaper (vinyl, polyethylene, and polyvinyl fluoride [PVF] films); porcelain
Table 10.10 Examples of coating performances

enamels; and electroplated, phosphated, or oxidized metal films. In addition, coatings and their
substrates compete against structural materials that require no special surface coatings, such as
stainless steel, aluminum, glass, stone and brick, RPs, extruded plastics, and molded plastics. How-
ever, there are many new applications in which materials such as steel, aluminum, wood, concrete,
and brick are given plastic coatings to provide more durable and attractive products.
To meet competition,the paint industry continues to develop new formulations and new meth-
ods of applications. Since the best performance per unit cost is desired, there is continual effort
to lower the cost per square foot per surface coated, either by lowering material costs per pound,
using thinner films, or devising more economical means of application.Application techniques have
involved extensive laboratory tests with different composite resins.
Thermoplastic Coating
Serviceable TP films must have a minimum level of strength that depends on the end use of the
product. Film strength depends on many variables, but a critical factor is molecular weight (MW).
MW varies with the chemical composition of the plastic and the mechanical properties required for
the application. For example, in solvent evaporation from solutions of TPs for spray applications,
consideration has to be given to the solvent’s evaporation behavior. With a methyl ethyl ketone
(MEK) solvent and a vinyl copolymer that has a relatively high vapor pressure under application
conditions, MEK evaporates quickly.
With this type of system, a large fraction of the solvent evaporates in the time interval between
the coating leaving, as an example, the orifice of the spray gun and its deposition on the surface
being coated. As the solvent evaporates, the viscosity increases and the coating reaches the dry-
to-touch state soon after application and does not block. However, if the film is formed at 77°F
(25°C), the dry film contains several percent of retained solvent.
In the first stages of solvent evaporation from such a film, the rate of evaporation depends
on the vapor pressure at the temperatures encountered during evaporation, the surface area-to-
volume ratio of the film, and the rate of airflow over the surface. It is essentially independent of the
presence of plastic.The rate of solvent diffusion through the film depends not only on the tempera-
ture and the glass transition temperature (Tg) of the film, but also on the solvent structure and any
solvent-plastic interactions.The coating thickness is another parameter that affects solvent loss and
film formation.
TP-based coatings have a low solids content because their relatively high MWs require large
amounts of solvent to reduce the viscosity to levels low enough for application.Air pollution regu-
lations limiting the emission of volatile organic compounds (VOCs) and the increasing costs of
solvents have led to the increasing replacement of these coatings with lower-solvent or solventless
coatings. However, large-scale production means that solvent-coating systems become economi-
cally beneficial when used with a solvent-recovery system.

Coating 23
Latex
Emulsions of latex (or paint) have low solvent emissions as well as other advantages. Latex is a
dispersion of high-MW plastic in water. Charge repulsion and entropic repulsion (also called steric
repulsion and osmotic repulsion) stabilize the dispersion. Because the latex plastic is not in solu-
tion, the rate of water loss is almost independent of composition until the evaporation gets close
to its end.When a dry film is prepared from latex, the forces that stabilize the dispersion of latex
particles must be overcome, and the particles must coalesce into a continuous film. The rate of
coalescence is controlled by the free volume available, which in turn depends mainly on Tg.The
viscosity of the coalesced film also depends on the free volume.
With latex or paint emulsion, coating material is made of two dispersions: (1) dry powders
with colorants, fillers, and extenders and (2) plastic dispersions.These emulsion paints have the
binder in a water-dispersed form. Principal types are styrene-butadiene, PVAc, and acrylic plastics.
Percentage composition by volume is usually 25% to 30% dry ingredients, 40% latex, and 20%
water plus stabilizer.Their unique properties are ease of application, absence of disagreeable odor,
and nonflammability; they are used both indoors and out.
TS Coating
A potential problem inTS plastic systems is the relationship between storage stability of the coating
before application and the time and temperature required to cure the film after application.The
processing ofTSs is different than that ofTPs (chapter 1). It is desirable to store a coating for many
months or even years without a significant increase in viscosity caused by cross-linking reaction
during storage. However, after application, the cross-linking (cure) should proceed in a short time
at as low a temperature as possible.
Since reaction rates depend on the concentration of the polymer’s functional groups, using
more dilute systems can increase the storage life, which is achieved by adding more solvent.When
the solvent evaporates after application,the reaction rate will initially increase.Although it is advan-
tageous to reduce solvent concentration as much as possible, the problem of storage stability has to
be considered for systems with a higher solids content.
The mechanical properties of the final film depend on Tg for the cross-linked polymer and the
degree of cross-linking, or the cross-link density (chapter 1).The average functionality, the equiva-
lent weight of the system, and the completeness of the reaction (complete cure of theTS) affect the
cross-link density.
FUNDAMENTALS OF RESIN FORMATION
There are two classes of resins: they can be identified as condensation or addition types (chapter
1). Condensation polymerization is the process by which a polymer is built up by successive reac-
tions between monomer molecules and the growing polymer. In each reaction step, condensation

polymerization produces a small molecule such as water, hydrogen chloride, or sodium chloride
and increases the polymer size.
Addition polymerization is the process by which a polymer is built up by a repeated addition
reaction between monomer molecules and the growing polymer. This action occurs within any
other reaction product when the polymer is being formed.The monomer, in the majority of cases
of practical importance, is an unsaturated compound, usually a vinyl derivative.While an addition
polymer has the same elementary composition as the monomer, this is not true for condensation
polymers.A review of some of the resins used in coating follows (chapter 2).
Condensation Type
Alkyd resin
Many variations in the constituents and portions of the alkyd coating material are available. Many
different binders, such as drying oils, phenolic resins, amino resins, nitrocellulose, maleic resins,
chlorinated rubber and cyclized rubber can be used. As a group, the alkyds are distinguished by
rapid drying, good adhesion, elasticity, resistance to marring, and durability.
Their principal weakness resides in the facility with which the ester groups, which form a large
part of the molecules, are hydrolyzed (particularly under alkaline conditions). Even in this respect
it is possible to produce alkyds with greatly improved resistance to hydrolysis through the use of
polyols.
Alkyd resins are instrumental in the coatings used in producing automobiles, refrigerators,
washing machines, and many other consumer goods. Styrenated alkyds (in contrast to the styre-
nated oils) have been used with a fair amount of success as binders in very rapid air drying and rapid,
low-temperature stoving finishes.Alkyds are also modified with vinyl derivatives such as esters of
acrylic and methacrylic acids, or with mixtures of these compounds and styrene or vinyl-toluene. It
appears that none of these combinations has experienced practical commercial success.
Polyester resin, unsaturated
The unsaturated polyesters are of particular interest in the coatings field.The monomer may be
used to adjust the viscosity of the coating to the required value. In most cases this action occurs in
conjunction with small amounts of solvents. It has had limited successful use in the coating industry
principally due to the fact that the curing is strongly inhibited by atmospheric oxygen.The result is
that the surface of the polyester coating remains soft and sticky.
Phenolic resin
The first phenolic resin appeared on the market in 1902. It was a spirit soluble, nonhardening
Novolac type. It was intended as a substitute for shellac and spirit varnishes. In 1907, Baekeland’s
historic patent for the preparation of phenolic resin molding compound was published.This type of

Coating 25
phenolic resin was not suitable for coatings.The first patentfor oil-soluble phenolic resin was issued
in 1913.There followed different patents for different phenolic resin coating formulations. Many
different types are now available with extensive service life.
Amino resin
A number of resins containing nitrogen are classed together as amino resins.This terminology tends
to be confusing but continues to be used.Amino resins are obtained by condensation of amino or
amido compounds with aldehydes.The most important are the urea and melamine resins (ther-
mosetting) and the aniline resins (TP; chapter 2).The thermosetting coatings are of interest in the
coatings field.
Urea resin
Urea resins are not used alone as binders and coatings.When they cure,the films are brittle and lack
adhesion.The usual modifiers are alkyd resins, as well as combinations with nitrocellulose. In the
latter case, however, the improved gloss tends to increase yellowing.
Melamine resin
Melamine is a white, crystalline powder with a high melting point. It differs from urea in that it
has very low solubility in water. Melamine resins are prepared in the same way as urea resins, by
condensation with formaldehyde.The melamine resins have replaced the urea resins in many appli-
cations.The most important use is in combination with alkyd resins.This combination improves
resistance to water, alkali, and chemicals. Virtually nonyellowing finishes may be obtained with
suitable choices of alkyds.
Epoxy resin
Epoxies have provided the surface coatings industry with a wide variety of formulation possibili-
ties.They are used alone or in combination with other plastics. Alhough they are more expensive
than other types of binders, their outstanding properties and versatility continue to expand their
applications.
Epoxy resins provide good chemical resistance and, in particular, excellent resistance to alka-
lis, including caustic alkalis.A major asset is their excellent adhesion to many different substrates.
Other important properties include exceptional hardness and flexibility.
One of the disadvantages of epoxy resins is that they are not soluble in the lower-cost solvents.
Compatibility with other film formers is limited. Finishes based on epoxy resins have a marked
tendency to chalk when used outdoors, and their water resistance is not always the best.
They are used in combination with phenolic, urea, and melamine resins, which act as cross-
linking agents. Cold-curing coatings with polyamines or polyamides as curing agents are very

popular.Air-dried coatings are also popular.They are produced after esterification with unsaturated
fatty acids.The product is known as epoxide ester or epoxy ester.
The combination of epoxy resins with phenolic resins can give maximum resistance to chemi-
cals and solvents,as well as adhesion,flexibility,hardness,and abrasion resistance.The most suitable
phenolic resins for cold blending are of the butylated resole type.
Polyamide (nylon) resins, which are formulated to contain free amine groups, can serve as
catalysts for epoxy resins.The polyamide resins are practically nontoxic and nonirritant to humans,
whereas some of the amine catalysts (used with epoxies) must be handled with special precautions.
The polyamide combinations produce tough films in combination with a lower resistance to sol-
vents and chemicals.
Polyurethane resin
There are many different types of urethane (e.g., PUR) coatings on the market. For coating applica-
tions, a cross-linked film is preferred and thermoplastic urethanes are of little interest.The usual
hazards associated with isocyanates are applicable in preparing these coatings.
With a suitable choice of components, it is possible to obtain almost any degree of flexibility
and hardness, ranging from highly elastic films for coating rubber and leather articles to extremely
hard, abrasion-resistant coatings for floors, boats, and metal objects.These coatings are important
in the coating industry.
Silicone resin
Silicone resins are heat-convertible and are used either alone or in combination with other bind-
ers in coatings. Their most important and distinguishing property is resistance to degradation
when exposed to high temperatures. In addition, they have good electrical properties and outdoor
durability.Suitably pigmented silicone coatings will withstand temperatures of 260°F (127°C) con-
tinuously, while most other coatings would not even survive long exposure at 150°F (66°C).
Silicone resins pigmented with aluminum powder or zinc dust give films with good weather
and corrosion resistance at temperatures as high as 500°F (260°C).Silicone finishes in the electrical
industry provide a combination of heat resistance and electrical insulation.
Addition Type
Polyethylene resin
The important and significant properties available with polyethylene binders are flexibility and
water and chemical resistance. However, since they are insoluble in all organic solvents at tempera-
tures below about 50°F (10°C), they are not used in normal surface coatings.They can be applied
directly from the solid by flame spraying. In most applications the substrate has to be pretreated in
order to provide suitable adhesion.

Coating 27
There are polyethylene compounds that are soluble in either urea or epoxy resins to provide
different types of coatings. These are constituted with chloro-and chlorosulfonyl groups. These
coatings make highly elastic films characterized by particularly good resistance to strong acids such
as concentrated hydrochloric and sulfuric acids, and to oxidizing agents such as ozone, hydrogen
peroxide, and chromic acid.They are not resistant to hot concentrated nitric acid.
An example of these special polyethylene compounds is DuPont’s Hypalon, which is combined
with other binders such as chlorinated rubber, urea resins, and epoxy resins to provide different
types of coatings.These different coatings are used in various chemical bath containers.
There are many different polyethylene coating compounds to meet many different coating
requirements. ExxonMobil Chemical has a new family of linear low-density polyethylene (LLDPE)
extrusion coating resins.The first of a new family of very low-density linear polyethylenes are pro-
duced with the company’s Exxpol metallocene technology for extrusion coating and laminating.
These new Exxco products are said to have “plastomer-like” properties and to significantly outper-
form conventional extrusion-coating resins in sealing ease,hot-tack and seal strength,tear strength,
puncture resistance, and adhesion to stretched oriented film.
Recommended uses involve blending with about 20% LDPE or ethylene-vinyl acetate (EVA)
for coating paper and paperboard.The initial grade, Exxco 012, has 0.912 g/cc density and 12 melt
flow index (MI).It is a close cousin to ExxonMobil’s new Exceed 1012CA metalloceneVLDPE film
resin of the same density and MI. However, Exxco is aimed specifically at coating and laminating.
ExxonMobil is exploring future Exxco grades with higher and lower MIs.
Vinyl resin
The principal vinyl resins used in coatings are copolymers of vinyl chloride and vinyl acetate. Poly-
vinylidene chloride (PVDC) and polyvinyl butyral (PVB) are also important. PVAc in emulsion
form is widely used in architectural coatings.
The vinyl copolymers produce air-drying coatings that have excellent toughness and good resis-
tance to water and chemicals. However, they are sensitive to heat, ultraviolet radiation, and many
solvents.They are high-MW polymers and therefore require fairly strong solvents. Development
of the dispersion type of vinyl resin permits their application as organosols and plastisols at high
solid content, which extends their usefulness considerably.They do not have high solids at spraying
consistency.
Vinyl resins are widely used as fabric coatings because of their combination of toughness and
flexibility, and their property of not supporting combustion. Because they are nonflammable, they
have replaced nitrocellulose lacquers for many applications on fabrics.
Vinyls produce excellent coatings on metals,but care must be taken in their application because,
like most high polymers, they have strong cohesive forces that may overcome the adhesive forces.
The entire coating may flake off as a continuous sheet if the precise application conditions have not
been complied with for the various modifications.

The absence of odor, taste, and toxicity in vinyl coatings makes them suitable for the lining of
beer cans. They have other applications in food containers but certain limitations exist, namely,
poor adhesion and sensitivity to temperatures reached in processing foods.
The vinyl copolymers can be used most efficiently in special applications such as hospital and
dental equipment, a field in which durability is more important than initial cost. For laboratory
equipment, epoxy resins may be preferred because the vinyls are sensitive to some solvents.Vinyl
coating systems consisting of corrosion-inhibiting primer and chemical-resistant finish coats are
used on new equipment for chemical plants. Metal conditioners based on zinc chromate and PVB
are widely used instead of sand-blasted steel on both industrial and marine equipment.
PVAc in the pure and solid form is colorless and transparent. It is somewhat brittle unless the
degree of polymerization is low. Its softening temperature is between 40°F and 90°F (4°C and
32°C), depending on the MW. It exhibits the phenomenon of cold flow.
Because of its water solubility, polyvinyl alcohol (PVAL) plays a relatively small part as a binder
in surface coatings. It has been used as an impregnant in the production of grease-proof paper, as a
yarn sizing, and for the production of water-soluble packages. It is useful as a dispersing agent and
a protective colloid, for example, in latex paints. It has an advantage over glue and casein in that it
is much less susceptible to microbiological attack.
Dispersion coating, PVC
At this time, most dispersion coatings available on the market are based on the PVC homopolymer
type of resin. Other types of dispersion coatings, such as those based on PVF and polyvinylidene
fluoride (PVDF), are also available in the marketplace. Major reference is made to the PVC types
of dispersion coatings.They have important applications in industrial finishes because of their econ-
omy and excellent performance characteristics.
The dispersion technique provides the advantage of the good properties of high-molecular-
weight vinyl chloride resins. Dispersion coatings are also known as organosols and plastisols.There
are also conventional solution vinyl coatings that perform well for the organic coatings industry.
These solution vinyl resin coatings are based on copolymers of vinyl chloride and vinyl acetate and
are of relatively low molecular weight. Polymers containing a third component are also used and
provide the industry with vinyl polymers that have carboxyl (–COOH) or hydroxyl (–OH) groups,
or are otherwise terminated for the attainment of special properties (Table 10.11).
Organosol and plastisol
It has long been known that the higher-molecular-weight vinyl resins produced films that gave the
best toughness and resistance properties. The resulting coatings, however, had poor adhesion to
metal substrates, gave very low solids when dissolved in even the strongest solvents, and exhibited
poor flow properties. By not dissolving this resin, but dispersing it suitably, this family of coating
materials became known as the dispersion coatings.

Coating 29
Vinyl dispersion is a suspension of colloidal-size particles in an organic medium, which is not
capable of dissolving the resin at room temperature but exerts some solvating or peptizing effect
on the polymer particles.When the organic medium contains volatile solvent, the mixture is called
an organosol. Mixtures that do not contain appreciable amounts of volatile thinners are referred to
as plastisols. Organosol dispersions normally contain 40% to 80% solids, whereas plastisols contain
90% to 100% solids.
The resin particle diameter range varies from 0.1 to 1.0 µm.Relative viscosity is in the range of
2.50 to 3.0 for the higher-molecular-weight resins and 2.05 to 2.4 for the lower-molecular-weight
materials. Relative viscosity, also referred to as viscosity ratio, is defined as the ratio of the viscosity
of a 1% resin solution in cyclohexanone at 25°C (77°F) to the viscosity of pure cyclohexanone at
25°C (77°F).
Table 10.11 General performance comparisons

Composition
In general, dispersion coatings are composed of the ingredients shown in Table 10.12.The liquid
phase of the dispersion system—the solvents,the diluents,and the plasticizers—performs multiple
functions, such as serving as a wetting aid, dispersing medium, viscosity depressant (thinner), stabi-
lizer, and fusion aid. Because of these multiple roles, these liquid components must be meticulously
selected to achieve a dispersion system with proper application and coalescing properties (Table
10.13). Not only must they be perfectly balanced for good flow properties to prevent flocculation
or oversolvation and even gelation of the dispersion resin, consideration must be also given to the
requirements of and interactions with the other formula ingredients, such as pigments, resins, and
other modifying materials.
Table 10.12 General composition of dispersion coatings
Table 10.13 Example of advantages using dispersion coatings

Coating 31
One of the defects noticeable in an organosol film with inadequate solvent balance is called
mud-cracking.The organosols are prone to this condition because they inherently tend to release
solvents very rapidly. In a deposited film, a too-rapid loss of solvent results in volume shrinkage and
hence causes mud-cracking.This condition can be avoided by combining a fast cure rate (to quickly
coalesce or fuse the tiny resin particles) with a slow solvent system to keep the film mobile for as
long as is necessary to obtain optimum film properties.
In some specially developed organosol coating systems, it is practically impossible to design
solvent systems that would produce good flow, aid in proper fuse-out of the film, and still be
viscosity-stable on storage. Such coating materials are sold as two-package systems.The organosol
component contains a balanced solvent system for the ingredients contained therein, yielding a
storage-stable liquid that may be clear or pigmented.The catalyst component, which may contain
the modifying resins or cross-linking agents, also utilizes solvents that are properly balanced for
this component and it, too, forms a storage-stable liquid, clear or pigmented, as the case may be.
The organosol and catalyst components are usually mixed equal parts by volume to form
a coating with the desired end properties. In approximately six hours (depending on specific
composition, ambient temperature and humidity), oversolvation may start and viscosity may
begin to rise. In such a case, a fresh, equal-parts mixture is added, and the blend may normally be
used with complete satisfaction. In commercial practice, the makeup or the replenishing coating
material effectively eliminates any practical concern regarding a rise in viscosity. Any catalyzed
mixture held over a weekend, for example, is merely checked for fluidity and added to a fresh,
equal-parts mixture.
When storing dispersion systems, one should recognize that the dispersants or polar solvents
are more powerful in their action at higher temperatures.Thus to avoid oversolvation, organosol
materials should not be stored in the hot sun, next to radiators, or in places where the coating tem-
perature may rise to higher than 120°F (49°C). Since solvent power falls off with the reduction of
ambient temperatures, undersolvation and possibly flocculation may occur if organosols are stored
outside for long periods during the winter in cold areas. Never heat up dispersion coatings rapidly
with devices such as immersion heaters or by oversolvation because gelation can occur.
Method of application
Dispersion resins can be applied by a variety of methods including spraying, knifing, rolling with
a roller, dipping, and extrusion.While spraying techniques are mostly reserved for organosols and
extrusion procedures for plastisols, the other methods are common to both types of system.The
choice of method of application or dispersion system (organosol or plastisol) is dictated by film
thickness requirements, available application techniques (spray, extrusion) and processing equip-
ment (shear mixers or roller mills), substrates, and product performance. It is interesting to note
that, due to the puffy or thixotropic nature of dispersion coatings, these materials can be applied
at much higher than normal viscosities.The shear forces exerted during recirculation and by the
nap of the roller coater, or during spraying or extrusion, are effective in reducing the actual coating

viscosity of these materials. In addition, the normal coalescence or fusion of the resin particles in
the baking oven assists flow.
Thixotropy is a property of a plastic that is a gel at rest but liquefies upon agitation and loses
viscosity under stress. Liquids containing suspended solids are likely to be thixotropic.They have
both high static shear strength and low dynamic shear strength. For example, these materials have
the capability to be applied on a vertical wall and through quick curing action remain in position
during curing.
All dispersion coatings must be properly baked or fused in order to coalesce the tiny dispersed
resin particles into a continuous, tough, and flexible film. Depending on formulation and dwell
time, the required fusing temperatures (based on actual metal temperatures) vary from 300°F to
525°F (149°C to 275°C).The preferred cycle for sheet bakes is 10 minutes in the 350°F to 525°F
(177°C to 275°C) range. In moving-web application (coil or strip coating), a cure cycle of 60
seconds or less at about 525°F yields good results.These cited examples, of course, are for vinyl
chloride dispersion systems. Fluorinated dispersion coatings require substantially higher tempera-
tures (approximately 550°F to 600°F [288°C to 316°C]) for proper film formation.
Since fusion of the dispersed particles is the major objective in the curing procedure, the
baking cycle for a given application depends on how quickly the wet film reaches fusing tem-
perature.When this critical temperature is reached, the tiny, partially solvated particles quickly
coalesce into a homogeneous coating. Problems of thermal degradation will occur if the coating
is subjected to temperatures in excess of 500°F (260°C) for vinyl chloride dispersion; degra-
dation will occur at temperatures in excess of 600°F (316°C) for vinyl or vinylidene fluoride
dispersions for prolonged periods.
In the instances of vinyl chloride dispersion, the rate of thermal decomposition is accelerated
in the presence of iron; such situations occur, for example, when microscopically exposed tin plate
is subjected to extreme temperatures for only a few seconds.The resulting film is discolored black.
Discoloration of this type can also mean that the oven has been set too high or has developed a hot
spot or another similar problem.To reduce these thermal effects, 0.5 to 15 parts per hundred (pph)
of a stabilizer is mixed in the dispersion composition. Effective stabilizers include metallic soaps,
organic tin and cadmium salts, and epoxide resins.
Vinyl and vinylidene fluoride systems,although more thermally stable than their vinyl chloride cous-
ins, undergo thermal decomposition at relatively high temperatures (>600°F).The process is greatly
accelerated in the presence of glass or silica and these materials are to be avoided in formulating these sys-
tems.Copper,aluminum,and iron show no catalytic degradation effects;although,surprisingly,titanium
dioxide shows a tendency to discolor the vinylidene fluoride systems and discoloration becomes more
pronounced with increasing pigment concentrations. Effective stabilizer products for these dispersion
resins are calcium-zinc complexes or pentaerythritol in combination with an antioxidant.
It has been found that film integrity, gloss, flexibility, and process or hot water resistance
are materially affected by the baking cycles used. In practice, the fusing cycle must be especially
established for each application. In general, optimum results are obtained when the coated metal
is exposed to relatively high temperatures in the first oven zone. As a result, the solvents in the

Coating 33
dispersion composition have an opportunity to help solvate the dispersion resin before they evapo-
rate. Of course, care must be taken to adjust the temperatures in the first oven zones so that no
blistering or pinholes occur. Based on practical and theoretical consideration with PVC disper-
sion coatings, it was determined that 335°F (169°C) is the minimum metal temperature at which
the PVC dispersion should be fused for good results.A recommended sheet-coating schedule, for
example, would be 340° to 365°F (171° to 185°C) for 6 to 10 minutes.A representative coil bake
would be 60 seconds at 500°F (260°C) for 0.6 mil film. Properly cured films thus baked achieve
tensile strengths of 8000 to 10000 psi (55 to 69 MPa). Elongation is approximately 300%. Similar
curing considerations apply to the fluoropolymers. However, these coatings require considerably
more energy to properly coalesce the film. Metal temperatures of 475°F (245°C), approximately
100°F (38°C) above those used for the vinyl chloride systems, are required.A representative coil
bake for these resins, for example, would be 425° to 475°F for 30 to 45 seconds.
Nonfoam strippable vinyl
Another group of chemical coatings, the uses of which have shown continued marked expansion,
are the nonfoam strippable vinyls. While these materials have been offered for some time, they
were formulated for spray application to products after fabrication.The more recent types, like the
roll-coat finishes, are designed for application by reverse roller coating to coiled metal before the
product is manufactured.Therefore, they offer surface protection all the way through metalwork-
ing operations, during assembly, and many times afterward as preliminary packaging.
These types generally consist of vinyl plastisols applied in liquid form and heat-converted into a
continuous film,generally at a minimum of about 2 mils dry.Here again improved resins have played an
important part in the superior performance of these materials by providing the materials with excellent
toughness as well as tensile and tear strength to withstand slitting,stamping,forming,and bending.
Formulated with just the right degree of cohesive properties to adhere until no longer desired,
these strippables can be used over a variety of substrates including polished or stainless steel, anod-
ized aluminum, or prefinished metal that has been coated withTS finishes.
Converters report different applications of their plastisol strippable vinyl in which users
reduced material and labor costs 50% by adopting this concept.The firms use the strippable vinyl
on anodized aluminum coil that is subsequently manufactured into products such as heating hoods.
For this application the strippable vinyl remains intact before, during, and after fabrication; acts as
preliminary packaging and protection against scratching from the final corrugated container; and
stays on until the hood is installed to protect it from installation handling.
Priortousingtheplastisolstrippable,companiesthatproduceheatinghoodsemployedpressure-
sensitive paper.This material was almost twice the cost per square foot of plastisol strippables and
had to be removed before the hood was shipped; thus additional packaging had to be used.
Architectural firms also use strippable plastisol coatings on stainless steel building panels. Here
they offer surface protection from, before, and during fabrication of the panels, up to the time at
which they are erected.

Foam-vinyl strippable
The foam-vinyl strippables are very useful for packaging metal parts and other similar products.
Based on PVC dispersion resins, foam vinyl strippables are applied in liquid form to the completed
product. Foaming takes place during their cure cycle to produce a highly resilient, spongy film.
Therefore, these strippables also offer protection against denting and scratching, and have taken the
place of paper and corrugated wrappings at substantial savings.
Within the past few decades, types of strippables that can expand up to 300% have been made
available.These types can yield maximum films of about ½ in, although films of ¼ in are more
commonly used.These materials afford many advantages. For instance, they retard corrosion by
forming a tight skin around the object, which inhibits the entrance of moisture.They also help to
save space since this tight fit allows more units to be stacked per cubic foot than if bulky containers
were used. In addition, because one type of strippable can accommodate products of all sizes and
shapes, there is no need to maintain a large inventory of different-sized packaging materials.While
auto parts packaging is one of their most common uses,foam vinyl strippables are also used in other
industries in which metal parts shipment prevails.
Plasticizer, PVC
This review of plasticizers is required because they play an important part in the environmental
performance of vinyl. Plasticizers serve three basic functions: to lower the processing temperature
of the polymer below the decomposition temperature, to modify the properties of the finished
product, and to modify the processing properties (chapter 1). Plastics can be made softer or flex-
ible, their natural properties can be extended or modified, and their viscosities can be reduced to
make them easier to shape and form at high temperatures and pressures.
The mechanism by which inclusion of plasticizers in PVC results in increased flexibility is
attributed to a reduction of the intermolecular forces. In other words, the plasticizer acts as a
lubricating agent to allow the macromolecules to slide over one another freely, or by the solvation
of the polymer. Unplasticized PVC is a three-dimensional gel formed by the attachments between
molecules at active centers. Plasticization is a reduction of polymer-polymer unions by creating
polymer-plasticizer unions in their place.
Plasticizers for PVC are generally divided into two categories: true plasticizers (primary and
secondary) and extenders. The primary types are materials that exhibit good compatibility with
PVC.The secondary types usually exhibit fair to good compatibility and are normally used in con-
junction with the primary plasticizers. One highly desirable property of a plasticizer is its capacity
to impart and maintain the characteristics of an elastomer to the polymer over the widest possible
temperature range. Unfortunately, no single plasticizer embodies all the desired combinations of
properties.Therefore, for any specific application, it is necessary to choose the correct plasticizer
combination.

Coating 35
Fluorine-Containing Resin
The high thermal stability of the carbon-fluorine bond has led to considerable interest in fluorine-
containing polymers as heat resistant plastic and rubbers such as polytetrafluoroethylene (PTFE).
PTFE is a material that also provides exceptional chemical resistance. It is completely inert to halo-
gens, fuming mineral acids, strong alkalis, and oxidizing agents. It also has the advantage of being
nonflammable. However, it is attacked by molten alkali metals. Its insolubility in organic solvents
makes it impossible for use in lacquers.With its high crystalline melting point of 330°F (166°C),
it cannot be used in organosols and plastisols. Other fluorine-containing plastics have been devel-
oped, but in almost all cases they are not available for use in the coating industry.
Acrylic Resin
Acrylic resins areTP polymers ranging from very hard and tough to extremely flexible water-white
materials.They are resistant to oxidation, ultraviolet degradation, and many chemicals. However,
certain solvents soften them.
They have been used for many years in specialty coatings.Acrylic resins have established a repu-
tation for excellent durability in automotive lacquers.They can be used with plasticizers as the film
former or in combination with nitrocellulose.The combination is somewhat harder and has better
resistance to solvents such as gasoline.
The very flexible types of acrylic resin have been used as coatings for elastic materials, such
as rubber, and for textile or leather coatings. Acrylic resins are compatible with many other film
formers and are often used in blends.Acrylic emulsions are used as binders in latex paints; the latex
paints have steadily increased in use as architectural coatings.Applications include interior plaster
and exterior stucco, concrete, and masonry surfaces.
The disadvantages that stem from theTP nature of the ordinary acrylic resins (solvent sensitiv-
ity and temperature sensitivity) have been overcome by the introduction of thermosetting acrylic
resins.They are cross-linked by stoving processes,very similar to those used for the alkyd-melamine
types.Water-soluble or emulsion types, as well as those soluble in organic solvents, are all available.
Cellulosic Resin
Nitrocellulose was the first synthetic high polymer used in coatings. Its lacquers are still considered
to be the fastest air-drying materials.This is due largely to its high softening point and good solvent
release. It is compatible with many other resins and plasticizing materials.
It provides hard furniture finishes, flexible coatings for paper and fabrics, and durable finishes
for automobiles.The principal limitations of such lacquers are their relatively high-cost solvents and
relatively low solids at spraying consistency, their sensitivity to heat and ultraviolet radiation, and
their high degree of flammability.

Ethyl cellulose is softer and more flexible than nitrocellulose. It is not as highly flammable as
nitrocellulose and has a certain degree of resistance to degradation by heat. Chemical resistance is
improved.They provide toughness in blends with hard resins and waxes for hot-melt coatings.
Cellulose acetate is used chiefly in plastics and sheeting. It has only a few specialty applications
in coatings. However, the acetate-butyrate has increasing uses. Its properties vary with the ratio of
acetyl and butyral groups. It is slightly softer than ethyl cellulose but has better resistance to mois-
ture absorption.
Copolymer Resin
Many different copolymers are used as binders in surface coatings.A few of these types have been
reviewed in this chapter (chapter 2). The styrene-butadiene copolymers are very popular. Many
different vinyl copolymers—such as vinyl chloride, vinyl isobutyl ether, vinylidene chloride, vinyl
acrylonitrile, and so on—are also used.
Coumarone-lndene Resin
The coumarone resins are materials of low MW.They are soluble in aliphatic, aromatic hydrocar-
bons and in oils.They areTPs, and because of their hydrocarbon character they are resistant to acid
and alkalis.
They show a marked tendency to yellow when exposed to light, and their durability is poor.
Because of these inherent restrictions, they have limited applications in coatings.Their main field of
use is in binders for aluminum and bronze lacquers, where their low acid value leads to stability in
the ready-mixed finish.As they are protected from the atmosphere by the layers of bronze pigment,
the durability of such finishes is surprisingly good. Improvements occur by adding tung oil.When
added in asphalt lacquers, improved gloss and alkali resistance occurs.
Parylene
This plastic permits pinhole-free coatings with the exceptional capability of producing outstand-
ing conformity and thickness uniformity. Ultrathin (35 to 3000 nm) parylene films are produced
called pellicles are produced.These coatings are used to protect units from airborne contaminants,
moisture, salt spray, and corrosive vapors while maintaining excellent insulator protection. The
coatings are also extensively used in the protection of hybrid circuits. Such coatings do not affect
part dimensions, shapes, or magnetic properties.
These transparent TPs are generally insoluble up to 302°F (150°C). At 518°F (270°C) they
will dissolve in chlorinated biphenyls, but the solution gels upon cooling below 320°F (160°C).
Their weather resistance is poor. Embrittlement is the primary consequence of their exposure to
ultraviolet radiation.
Parylene has a unique coating system. Also unique is the chemistry of the xylene monomer,
in which a substrate is exposed to a controlled atmosphere of pure gaseous monomer, p-xylylene

Coating 37
(PX).The coating process is best described as a vapor deposition polymerization (VDP).The mono-
mer itself is thermally stable but kinetically unstable.Although it is stable as a gas at low pressure,
upon condensation it spontaneously polymerizes to produce a coating of a high-molecular-weight,
linear poly (p-xylylene; PPX).
The p-xylylene polymers (PPXS) formed by the Gorham process are generically known as the
parylenes.The terms Parylene N,Parylene C,Parylene D,or Parylene HT refer specifically to coatings
produced from the original patents from Union Carbide Corporation’s dimers.The polymerization
process takes place in two stages that must be physically separate but temporally adjacent.
There are four primary variants of the polymer: Parylenes N, C, D, and HT.Although they all
have the same essential coating properties and are applied in the same manner, each has a unique
molecular form that results in specialized performance characteristics. Parylenes N and C are the
most commonly used variants; they are used in medical coating applications.Table 10.14 describes
the key properties of these parylenes (478).
Of all the variants, Parylene N offers the highest penetrating power. Because of its greater
molecular activity in the monomer phase, it can be used to coat relatively deep recesses and blind
holes.This form of parylene also provides slightly higher dielectric strength than Parylene C and a
dielectric constant that is independent of frequency.The lower dissipation factor and dielectric con-
stant of this parylene form enable it to be used for protecting high-frequency substrates in which
the coating is in the direct electromagnetic field.
Parylene C differs from Parylene N in that it has a chlorine atom on the benzene ring, provid-
ing a useful combination of electrical and physical properties.Among these properties is a very low
permeability to moisture and corrosive gases.Compared to Parylene N,Parylene C displays weaker
crevice-penetrating ability.
The parylene process has certain similarities to vacuum metallizing.The principal distinction
is that truly conformal parylene coatings are deposited even on complex, 3-D substrates, including
on sharp points and into hidden or recessed areas.Vacuum metallizing, on the other hand, is a line-
of-sight coating technology.Areas of the substrate that cannot be seen by the evaporation source are
shadowed and remain uncoated.
Parylenes have been used as beam splitters in optical instruments,windows for nuclear radiation–
measuring devices, dielectric supports for planar capacitors, dielectric film in high-performance
precision electrical capacitors, circuit boards, and electronic module coatings.They have also been
used for extremely fast-responding, low-mass thermistors and thermocouples, and medical devices.
Parylene has been used in a wide range of medical applications since the 1970s.These include cath-
eters and mandrels,stents,needles,cannulae,cardiac-assist devices,prosthetics,and circuitry.Certain
devices require a protective coating to isolate them from contact with moisture, gases, corrosive
biofluids, or chemicals.The different parylenes respond to sterilization in different ways, as shown in
Table 10.15. Coatings are also used to protect patients from contact with surgical items or implanted
devices that may not be biocompatible.Vacuum-deposited parylene is often the protective medical
coating of choice.Additionally, parylene may be used to deliver other functional properties, such as
electrical insulation, particulate tie-down, or increased lubricity (478).

Table 10.14 Examples of properties for Parylenes N and C
Table 10.15 Effect of various sterilization methods for Parylenes N and C

Coating 39
Applying parylene requires special,though not complex or bulky,equipment:a vaporizer,a pyrol-
ysis unit, and a deposition chamber.The objects to be coated are placed in the deposition chamber,
where the vapor coats them with a polymer.A condensation coating like this does not run off or sag
as in conventional coating methods, nor is it line-of-sight technology, as in vacuum metallizing. In
condensation coating, the vapor evenly coats edges, points, and internal areas.Although the vapor is
all-pervasive, holes can still be coated without bridging. Masking can easily prevent chosen areas from
being coated.The objects to be coated can also remain at or near room temperature, thus preventing
possible thermal damage.The quantitative nature of this reaction allows the coating thickness to be
accurately and simply controlled by manipulating the polymer composition charged to the vaporizer.
Process
The coating process technology of applying parylene film to a substrate involves a vacuum chamber
by means ofVDP.A dry, powdered precursor known as a dimer is converted by heat in the coating
system to form a dimeric gas, and heated further to generate a monomer gas that is passed to a
deposition chamber.
Within the chamber, it polymerizes at room temperature as a conformal film on all exposed
substrate surfaces. Parylene deposition has no liquid phase, uses no solvent or catalyst, and gener-
ates no gaseous by-products.There are no cure-related hydraulic or liquid surface-tension forces in
the coating cycle, and coated products remain free of mechanical stress.
This film becomes a linear, crystalline polymer with an all-carbon backbone and a high MW.
With the absence of polar entities, and substantial crystallinity, the film is stable and highly resistant
to chemical attack.The static and dynamic coefficients of friction for parylenes are in the range of
0.25 to 0.33.This dry-film lubricity is an important characteristic for certain applications, such as
medical catheter and guide-wire coatings.
APPLICATION
Coated products are all around us worldwide.This large industry produces two broad categories
of coatings, namely, the trade sales and the industrial finishes.Trade sales, or shelf goods, include
products sold directly to consumers, contractors, and professional painters for use in construction
or painting, refinishing, and general maintenance.These coatings are used chiefly on houses and
buildings, although a sizeable portion is used for refinishing automobiles and machinery.
Industrial finishes, or chemical coatings, encompass myriad products for application by manu-
facturers in factories or for industrial maintenance and protection.They are custom-made products
sold to other manufacturers for such items as automobiles, appliances, furniture, ships and boats,
metal containers, streets and highways, and government facilities.
Different applications are reviewed in this chapter.The following just provide additional appli-
cations.Table 10.16 provide a guide on painting plastics, where R = recommended and NR = not
recommended.To improve or provide bonding capabilities to NR substances, different primers or
surface treatments or both are used such as fluorination (Table 10.17; chapter 6).

Coil Coating
This section reviews coil coating and highlights a typical major application of coil coating. Coil
coating with plastics continues to be a very big business worldwide (Tables 10.18 and 10.19).
Table 10.20 reviews the properties of coil coating plastics. In the meantime, the coil coating indus-
try has been under pressure to eliminate the use of solvents. For example, in the past,TP polyester
Table 10.17 Surface energy of plastics as a result of fluorination
Table 10.16 Guide for applying paint coatings to plastic substrates

Coating 41
Table 10.18 Typical plastics used in coil coatings

coil coatings contained up to 40% of solvents such as glycol esters,aromatic hydrocarbons,alcohols,
ketones, and butyl glycol. It has been predicted that the solvent-based technology will not change
during the next decade because the industry heavily invested in equipment to handle solvents (374).
Such changes in technology require long testing before they can be implemented.The coil coat-
ing industry normally recovers energy from evaporated solvents either by at-source incineration
or by a recycling process that lowers emissions. Because of the large amount of solvents used, the
use of PVC and fluoropolymers in some formulations, and the use of chromates in pretreatments,
pressure remains on the industry to make improvements. The coil coating industry is estimated
consume about 50000 tons of solvents both in Europe and in the United States.About half of these
solvents are hydrocarbons.
According to the published studies, efforts to change this situation started in the early 1990s. By
the mid-nineties research data were available to show that the technology can be changed.Two direc-
tions that will most likely challenge the current technology are radiation curing and powder coating.
Coil coats are thin (about 30 µm wet thickness) but contain a high pigment loading.Consequently,
ultraviolet curing is less suitable than electron beam curing.The application of this technology requires
a change to the plastic system, and acrylic oligomers are the most suitable for this application.These
systems can be processed without solvents. If a reduction in viscosity is required, it can be accom-
plished with plasticizers (the best candidates to date are branched phthalates and linear adipates) or
reactive diluents, such as multifunctional monomers, or both. Results show that the ultraviolet stabil-
ity of the system needs to be improved by using a polyester topcoat or fluoroplastic.
Table 10.19 Coil coating plastic characteristics and applications

Coating 43
With a topcoat, the materials perform very well, as observed in laboratory experiments and in
industrial environments.At the time of the study, which took place in the mid-nineties, the process
of coating was less efficient than solvent-based systems because production speed was about six
times slower than the highest production rates in the industry (120 m/min).At the same time, it
is known that the quality of solvent-based coatings suffers from excessive production rates. Radia-
tion curing has a disadvantage because of its high capital investment, but it does have an economics
advantage because the process is very energy efficient. Radiation curing technology has been suc-
cessfully implemented in several industries, such as paper, plastic processing, and wood coating,
where long-term economic gains made the cost viable.
Comparisons of solvent-based fluoroplastic powder coating developed in Japan show that
the elimination of solvent is not only good for the environment but also improves performance
(ultraviolet stability especially is improved).The study was carried out with a very well-designed
testing program to evaluate the weathering performance of the material.
Table 10.20 Plastic properties of coil coatings

These two technologies show that there is extensive activity to improve coil coatings with
simultaneous elimination of solvents. Two recent patents contribute more information on the
developments in the coil coating industry. One problem in the industry is the poor adhesion of the
coating to steel.There is a primer that contains dipropylene glycol methyl ether and PM acetate that
allows the deposition of relatively thick layers (20 to 40 µm) without blistering and at suitable rate
of processing. However, the primer has a low solids content (30% to 45%).A new retroreflective
coating that is based on ethyl acrylate-styrene copolymer was developed, which contains a mixture
of xylene with another aromatic hydrocarbon at relatively low concentration (11% to 12%).
Strippable Coating
There are different plastic types of strippable coatings to meet different requirements. A popular
type uses vinyls that are for protecting metal parts being packaged for shipment. PVC dispersion
plastic is applied in liquid form to the product. Foaming takes place during their cure cycle to
produce a highly resilient, spongy film.Therefore, these strippables also offer protection against
denting and scratching, and have taking the place of paper and corrugated wrappings at substantial
savings.Types that can expand up to 300% have been made available.These types can yield maxi-
mum films of about ½ in, although ¼ in is more commonly used.
Spraying, dipping, flow and curtain coating can apply foam vinyl strippables over the same
substrates as the nonfoam types (Fig. 10.3). Their primary use is on chrome-plated automotive
replacement parts, such as bumpers, headlight bezels, and decorative trim. Strippables usually
Figure 10.3 Temperature distribution in strippable vinyl foam.

Coating 45
boost production of wrapped parts considerably, as well as lowering the reject rate. Output of
wrapped bumpers, for example, was increased by three times.
Germ-Free Coating
Past attempts to create surfaces with inherent bactericidal properties capable of rendering them free
of germs have been unsuccessful. Researchers at Northeastern University, working with colleagues
at the Massachusetts Institute ofTechnology andTufts University (all in the Boston area), believe they
may have developed a method for creating permanently germ-free dry surfaces (479).They speculate
that previous efforts to design dry bactericidal surfaces failed because the polymer chains that made up
the material were not sufficiently long and flexible enough to penetrate bacterial cell walls.
Their research has demonstrated that covalent attachment of N-alkylated poly(4-vinylpyridine;
PVP) to glass can make surfaces permanently lethal to several types of bacteria on contact. The
group found a narrow range of N-alkylated PVP compositions that enable the polymer to retain its
bacteria-killing ability when coated on dry surfaces. It is believed that these are the first engineered
surfaces proven to kill airborne microbes in the absence of a liquid medium.
Work previously conducted on different compositions had limitations.Their polymer chains
had insufficient length and flexibility.Their polymer includes a long linker that enables the toxic
N-alkylated pyridine groups to cross the bacterial envelope.
According to the Boston-area researchers cited previously, dry surface-bonded PVP with no
N-alkyl chains or long N-alkyl chains, including ten or more carbon units, is not bactericidal.They
reported that three-to eight-unit PVP chains derive a sufficient positive charge from the cationic
pyridine nitrogen to repel each other and stay flexible and sufficiently hydrophobic to penetrate
bacterial cell walls. It has been indicated that surfaces fabricated in this way kill 94% to 99% of
bacteria sprayed on them. Because the coating is chemically bonded to the surface, it will not be
affected by being touched or washed.
EVALUATION METHOD
Severe near-future requirements for resin protective coatings demand the use of all available
methods of characterizing candidate materials. Examples include thermal, optical, and electrical
methods.The two main thermal methods to consider are thermogravimetric analysis (TGA) and
differential thermal analysis (DTA; chapter 22). Both may be used to characterize potential coating
materials under conditions that would provide information for the best selection, formulation, and
application of these materials by investigating their thermal degradation patterns and mechanisms.
The optical methods of interest are spectrophotometric and photomicrographic. Spectropho-
tometry is used to investigate the changes in optical properties of coatings that have been subjected
to various environmental conditions.Photomicrography can be used to either examine or determine
the metal-coating interface. It can also be used to determine if a coating is crystalline, amorphous,
continuous, or lacking in integrity.

An important electrical method is the measurement of the dielectric breakdown point of a
coating.The instruments that are used for this purpose can also be used to determine the porosity
and uniformity of a coating (chapter 22).
PROCESS
Overview
BothTPs andTS plastics may be used as coatings.The materials to be coated may be plastic, metal,
wood, paper, fabric, leather, glass, concrete, ceramics, and so on. Methods of coating are varied, as
shown inTable 10.21:
Table 10.21 Coating methods related to performances

Coating 47
Base material
A = woven and nonwoven fabric
B = paper and paperboard
C = plywood and pressed fiberboard
D = plastic films
E = metal sheet, strip, or foil
F = irregular flat products
G = irregularly shaped products
Coating composition
Q = powdered resin compositions
R = aqueous latexes, emulsions, dispersions
S = organic lacquer solutions and dispersions
T = plastisol and organosol formulations
U = natural and synthetic rubber compositions
V = hot-melt compositions
W =TP masses
X = oleoresinous composition
Y = reacting formulations (e.g., epoxy and polyester)
Z = plastic monomers
The processes include extrusion (Fig. 10.4; chapter 5); roller coating (Fig. 10.5); knifing or
spreading (Fig. 10.6); transferring (Fig. 10.7); cast-transferring (Fig. 10.8); dipping (Fig. 10.9);
vacuuming (Fig. 10.10); in-mold via reaction injection molding (Fig. 10.11; chapter 12); electrode-
position (Fig. 10.12); spraying (Table 10.22); fluidized bed; brushing; floccing; microcapsulation;
radiation; and many others (a few will be reviewed). Calendering of a film to a supporting material
is also a form of coating that tends to be similar to roll coating (chapter 9). Processes are also used
to coat specific products such as floor covering (Fig.10.13) and foamed carpet backing (Fig.10.14).
Surface coatings are usually composed of viscous liquids.They have the three basic components
of a film-forming substance or combination of substances: a binder, a pigment or combination of
pigments, and a volatile liquid.The combination of binder and volatile liquid is usually called “the
vehicle.” It may be a solution or a dispersion of fine binder particles in a nonsolvent. No pigments
are included if a clear, transparent coating is required.The composition of the volatile liquid pro-
vides enough viscosity for packaging and application, but the liquid itself rarely becomes part of
the coating.
Film coatings can involve chemical reactions, polymerization, or cross-linking. Some films
merely involve coalescence of plastic particles.The various mechanisms involved in the formation
of plastic coatings are as follows:

Figure10.4 High-speedextrusioncoatingline.

Coating 49
Figure 10.5 Example of roller coating processes.

1. Coating formed by chemical reaction, polymerization, or cross-linking of epoxy,TS
polyester, PUR, phenolic, urea, silicone, and so on
2. Dispersions of a plastic in a vehicle; after removal of the vehicle by evaporation or
bake, the plastic coalesces to form a film of plastisol, organosol, water-based or latex
paint, fluorocarbons, and so on
3. Plastic dissolved in a solvent followed by solvent evaporation to leave a plastic film of
vinyl lacquer, acrylic lacquer, alkyd, chlorinated rubber, cellulose lacquer, and so on
4. Pigments in an oil that polymerizes in the presence of oxygen and drying agents of
alkyd, enamels, varnishes, and so on
5. Coatings formed by dipping in a hot melt of plastic such as polyethylene or acrylic
6. Coatings formed by using a powdered plastic and melting the powder to form a
coating using many differentTPs
Figure 10.7 Transfer coating of PUR (top) and PVC.
Figure 10.6 Knife spread coating.

Coating 51
Figure10.8 Castcoatinglineforcoatingbytransferfrompapercarrier.

Figure 10.9 Fabric dip coating line.

Coating 53
Figure10.11 In-moldcoatingusedinthereactioninjection
moldingprocess.
Figure10.10 Exampleofavacuumcoater.
Figure10.12 Electrodepositionforapplicationofcoatingto
magnetwireorstrip.

Figure10.14 Foamplasticcarpetbackingcoatingline.
SPREADCOAT
FOAMCOMPOUND
FOAMEXPANSIONOVEN
400–425ºF
BELT
PRECOAT
APPLICATOR
CARPETLETOFF
CARPET
ROLLUP
TEFLONCOATED
STEAMHEATED
DRUM
POSTHEATOVEN
300–325ºF
Figure10.13 Floorcoveringcoatingline.

Coating 55
Equipment for coating lines can be associated with end-use markets, with some overlapping.
Substrates or web-handling characteristics distinguish the differences among thin plastic film,paper,
and paperboard combinations. Flexible packaging extrusion lines are using progressively thinner
substrates of polyester, oriented polypropylene, metallized materials, and so on.Thin snack-food
substrates require minimum tensions to assure that preprinted webs are not distorted.
Features include DC regenerative unwinds and in-feed holdbacks for precise and low-level
tension; direct or reverse gravure for aqueous PVDC and other plastics; coating; infrared preheat-
ing; and vacuum rolls for web control.The concept of tandem operations or coating two sides of
a substrate continues to expand to many flexible packaging lines that produce all kinds of combi-
nations (different plastics, paper, aluminum foil, wood, steel sheet, etc.) and coating a plastic for
heat-sealing. Higher operating-line tensions are used in producing structures with paper for granu-
lated or powdered mixes and freezer or sugar-wrap materials. Different plastics, such as ionomers,
acrylics, nylons, EVOHs, and EVAs, may be part of a converter’s inventory of resins.
The combination of aluminum foil and barrier resins extends existing technologies to create
lines with triple or quadruple (or more) coating systems and includes coextrusion in one or more
locations.
Film Solidification
When the coating is applied to the surface, the volatile liquid evaporates, leaving the nonvolatile
binder-pigment combination as a residual film; it may or may not require a chemical conversion to an
insoluble condition. Small amounts of additives are often included to improve application, pigment
settling,drying,and film properties.Most binders are either high-molecular-weight,nonreactive plas-
tics or low-to medium-molecular-weight, reactive plastics capable of being further polymerized via
chain-extension or cross-linking reactions to high-molecular-weight films (chapter 1).
Table 10.22 Examples of spray coating methods related to transfer efficiency

Most coatings are manufactured and applied as liquids; they are converted to solid films once
they are on the substrate. Powder coatings are applied as a solid powder, converted to a liquid on
the substrate, and then formed into a solid film.
Coating films are viscoelastic, so their mechanical properties depend on the temperature and
the rate of stress application. Their behavior approaches the elastic mode with increased tensile
strength to failure (breakage) or decreased elongation to failure, and with a more nearly constant
modulus as a function of stress when the temperature decreases or when the rate of application
of stress increases (chapter 19). The shifts can be especially large if results are compared above
and below the glass transition temperature (Tg; chapter 1). Below Tg, the coatings have an elastic
response and are therefore brittle; they break if the relatively low elongation to failure is exceeded.
Above Tg, the viscous component of the deformation response is larger; the films are softer (lower
modulus) and less likely to break during forming. Caution is required in considering the relation-
ship of Tg to formability because some materials, such as acrylic and especially PC, are ductile at
temperatures far below Tg. Above Tg, the modulus is primarily controlled by the density of the
plastic cross-linkages.
After a coating is applied, solvent evaporation and rheological factors contribute to the solidifi-
cation or curing of the coating film. Solvent initially evaporates from the surface of the film at about
the same rate as it would in the absence of a binder.As the film solidifies, evaporation slows down
because the diffusion rate to the surface is usually slower than the evaporation rate. Lacquer films
do not cure by chemical reaction to achieve the required hardness and toughness.They just dry
by solvent evaporation and depend on the high MW of theseTP materials to provide the required
performance. Latex paints behave in a similar manner.
Coating Methods
Many different methods are used to apply plastic coatings to substrates of all sizes and types,ranging
from the simple to the complex.They are generally composed of one or more plastics, a mixture of
solvents (except with powder coatings), commonly one or more pigments, and frequently several
additives. Coatings can be classified as TPs or TSs. Coating methods are categorized in different
ways by the different industries that require them.
Traditional paints contain a vehicle, a solvent, and a pigment. Some are applied by spraying
or dipping. Other systems involve heating parts and spraying them with a dry plastic powder that
coalesces on the hot part to form a film.The differences among the various coating systems are
the mechanism of film formation and the type of plastic being applied. Many important details are
involved in surface preparation and in application techniques.
Both solvent-borne and aqueous paints are used. Paints are usually classified on the basis
of the binder (vehicle) used. The most often used are (1) acrylics (aqueous acrylic emulsions,
solvent-borne enamels, melamine, and other modified acrylic emulsions); (2) PURs (aqueous
and solvent-borne); (3) alkyds and modifications; (4) epoxies and modifications; (5) polyesters;

Coating 57
(6) vinyls and modifications (latex or solvent-borne); (7) nitrocelluloses (solvent-borne); and
(8) polyamides (solvent-borne).
The distinction between paints and enamels is not straightforward. However, enamels gener-
ally contain higher MW binders and are formulated with lower solids concentration.They are also
formulated at lower pigment–binder ratios to create a superior gloss.
Lacquers differ from paints and enamels because they are compounded with TPs, which are
soluble plastics of much higher MW and low chemical reactivity. Film formation occurs by solvent
evaporation. Conventional lacquers are normally solvent-borne. Dispersions of plastics in water,
latexes, or organic vinyl liquids (organosols) yield soluble films ofTP; they also qualify as lacquers.
Plastisols are dispersions of finely divided vinyl in plasticizers that are nonsolvent at room tempera-
ture but are good solvents at high temperatures.They are stable under normal storage conditions
and can be coalesced into films at elevated temperatures.
Some plastic products that require painting may need special considerations because of their
surface conditions. Some plastics may be sensitive to certain solvents, so take care to understand
the situation.
Plastic coating substrates represent a big business. The substrates may be (1) films such as
plastics and aluminum foils; (2) papers; (3) fabrics that are woven or nonwoven or both; (4) con-
crete, stone, and other types of masonry; (5) panels of wood, steel, and so on; (6) profile shapes
made from different materials; (7) tanks and storage bins; and so on.The coating material provides
many properties required to make the substrates more useful in commercial and industrial applica-
tions. Considerations in selecting the plastic coating include such factors as chemical environment,
mechanical properties, processing characteristics, and costs.
Films are coated to extend the utility of the substrate by improving existing properties or
adding new and unique properties. The coatings can provide heat sealability; impermeability to
moisture,water,vapor,perfumes,and other gases;heat and ultraviolet barriers;modified optical or
electrical properties; altered coefficients of friction; and a tendency toward blocking.
Coatings are different from laminations of two or more films. Laminates vary in construction:
plastic film to aluminum foil, two or more plastic films combined, plastic film to paper to plastic
film, paper to plastic film to paper, and so on.With plastic films, the coatings are usually thinner
than the base film.Coatings are generally 0.05 to 0.2 mil (1.3 to 5.1 µm) thick.In laminations most
films are at least 0.25 mil (6.4 µm) thick, and more commonly 0.5 to 2 mil (13 to 51 µm) thick.
Different desirable properties of a fabric can be supplemented by plastic coating.The fabrics
provide at least tensile and shear strengths with elongation control. Coatings can protect the fab-
ric, reduce porosity, provide decorative effects, and other benefits. Coated fabrics are designed for
specific applications. The three major considerations are the physical environment, the chemical
environment (water, acid, solvents, and so on), and cost. Impregnation is the process of thoroughly
soaking and filling the voids and interstices of the substrate (as well as wood and paper) with the
plastic coating.The porous materials generally serve as reinforcements for the plastic after the coat-
ing treatment.

Processing is dictated by the properties of the substrate and the coating.The viscosity of the
coating must permit flow around the yarn or fiber surface. In extrusion and calendering, pressure
and heat fluidize the coating. In other processes, solution or dispersion can reduce viscosity.
Wall coverings, upholstery, and apparel are examples of decorative coated fabrics. Inks are
applied with one or more gravure printers to correct the color or to add a pattern. Relief patterns
are obtained by applying heat and pressure with embossing rolls.
There are leather substitutes that are designed to imitate the appearance of leather with its sur-
face grain.This is accomplished by coating substances that are capable of forming a uniform film.
Plasticized PVC first met this requirement during the 1940s.When plasticized PVC (solid or foam)
is coated onto a substrate, it produces a leather-like material called vinyl coated fabric. It exhibits
high density, very low water-vapor permeability, cold touch, poor flex endurance, and poor plas-
ticizer migration. But it has good scratch resistance and colorability as well as being inexpensive.
PUR coated fabrics, developed in the 1960s, were an improvement. PUR is coated on woven
or knitted fabrics.With a Tg below 32°F (0°C), PUR is very flexible at room temperature without
a plasticizer. Another important characteristic is that its molecular structure allows water-vapor
permeability. In addition, the solvents normally used for a PUR will permit coagulation by a non-
solvent with formation of a porous structure.The result is increased flexibility and water-vapor
permeability.
Drying a cast PUR solution to form a film that is laminated onto the substrate will produce
ordinary PUR-coated fabrics. Significant improvements in appearance, feel, and grain are accom-
plished by using a brushed fabric as the substrate.It is laminated with a cast PUR film.Alternatively,
an organic solvent solution of PUR is applied to a brushed, woven fabric immersed in a nonsolvent
bath for coagulation.
The poromerics are also called synthetic leather.They were developed during the 1960s as an
improvement over fabrics coated with leather-like coatings, whose applications were limited by the
properties of the knitted or woven substrate. Poromerics use a nonwoven fabric impregnated with
plastic, which thereby creates a substrate resembling leather. Fine fiber construction provides the
desired softness. Prepared with PUR, the poromeric coating layer corresponds to the grain of the
leather.
Historically, smoke and the resulting toxic fumes caused by the burning of a flammable sub-
strate were part of any fire, regardless of whether a fire-retardant treatment was applied.What was
needed was to smother the fire and thus stop the generation of toxic smoke and prevent further
damage to the substrate. Intumescence coatings were developed over a half-century ago by the US
Navy for use on ships. Industry projects developed different types of water-resistant intumescent
coatings.These intumescent coatings, when subjected to fire, form a char between the substrate
and the fire source.The basic product becomes flameproof.
Intumescence coatings provide the most effective fire-resistant system available, but origi-
nally they were deficient in paint color properties. Since, historically, the intumescence-producing
chemicals were quite soluble in water,coatings based on those chemicals did not meet the shipping-

Coating 59
can stability, ease of application, environmental resistance, or aesthetic appeal required of a good
protective coating.
Coating Equipment
There are different methods used; examples are shown in Figure. 2.4 and Figure 2.5. Each has its
performance advantages and cost benefits. Coating equipment is used to apply a surface coating, a
laminating adhesive, and any compounds for saturation or impregnation (or both) of a fabric.The
equipment has three basic components: the coating head, a dryer or other coating solidification
unit, and web-handling hardware (drives, winders, edge guides, controls, etc.). It can generally
coat various substrates in roll or sheet form.
Coatings can be applied directly to the substrate or transferred to the substrate from another
surface, such as a roll.Transfer from another surface is used when the substrate is sensitive to the
coating material, when it may be damaged by exposure to oven temperatures, for special secondary
operations such as applying pressure-sensitive labels, and so on.
During its application, the coating must be sufficiently fluid to be spread into a uniformly thin
layer across a web. Coatings can be applied as solutions in organic solvents, as aqueous solutions or
emulsions, or as molten or softened solids. Solutions and emulsions require drying to obtain solid
coatings. Cooling solidifies hot melts. Some coatings may be applied as reactive liquids and then
polymerized by infrared or heat.
Heat and mass transfer take place simultaneously during the drying process.The heat is trans-
ferredbyconvectioninairdryers,byradiationininfrareddryers,andbyconductionincontact-drum
dryers.The drying equipment usually has a means to remove and recirculate the vapor with heat-
exchange equipment to conserve energy.
The coating head accomplishes two functions.It applies the coating to the substrate,distributing
it uniformly in metered amounts over the surface. Most coaters fall into the following categories:
roll, knife, blade, or bar.There are also extrusion or slot-orifice coaters.
Roll coaters, the most widely used kind of coater, are subdivided by their construction, such
as direct, reverse, gravure, or calender. Examples of coating equipment include the following:
roll coaters, knife bar coaters, curtain coaters, and equipment for coil coating, vacuum coating,
spray coating, floc coating, electrodeposition coating, powder coating, fluidized bed coating, elec-
trostatic coating, electrostatic fluidized coating, flood coating, microencapsulation coating,
pinhole-free thin coating, and radiation curing (1).
Roll-Coat Finish
Referred to as “roll-coat finishes” because they are applied to coiled metal by the reserve roller-
coating technique (similar to offset printing), these finishes have grown into a sophisticated group
of materials since their inception about 80 years ago and are now offered in a wide variety.Their
primary advantage is that they can withstand metalworking operations without any resulting surface

damage.Thus they can be applied before product fabrication, which eliminates finishing steps after-
ward and can thereby cut costs.
With the wide range of resins, there are types of roll-coat finishes that are extremely flexible,
capable of taking very severe forming operations with no cracking or loss of adhesion. Conse-
quently, they are being used for applications involving rigorous bends, which before prohibited the
use of precoated metal for lack of finishes with enough formability. One such material is a vinyl
coating. It can satisfactorily withstand one of the most troublesome bends, the zero radius or back-
to-back bend.There are also flexible acrylics and polyesters.
Another advantage offered by these materials is the broad range of decorative effects they can
achieve, which also has been boosted by the wider variety of resins available.
Because roller coating is a high-speed operation, these roll-coat finishes have to cure quickly.
Therefore, modifications have been made to upgrade the performance of plastic resins in this area.
An average baking cycle today is 60 seconds at 500°F (260°C), in which time over 200 ft of coil is
coated.With coil coaters operating at even greater speeds, the resins have to cure in shorter bakes.
Other properties of the roll-coat finishes that have been continually improved a great deal are their
exterior durability, chemical resistance, and color retention.
Spread Coating
In spread coating, the material to be coated passes over a roller and under a long blade or knife.The
plastic coating compound is placed on the material just in front of the knife and is spread out over
the material.The thickness of the coating is basically regulated by the speed at which the material
is drawn under the knife and the position of the knife. In roller coating, two horizontal rollers are
used. One roller picks up the plastic coating solution on its surface and deposits it on the second
roller that, in turn, deposits the coating solution on the supporting material. The usual coating
material is a plastic melt but plastics in the form of fine powders are also used.
Floating Knife Coater
This coating machine applies a uniformly controlled amount of forming, sizing, or other desirable
material to a web or a sheet of substrate.The choice of coater (spread, spray, roll, dip, and air knife)
depends on the type of coating and the substrate.Other factors such as solvent removal,drying,and
production rate must be considered.
Spread coaters include the knife or bar coaters that scrape off a heavy layer of coating liquid to
the desired thickness.The floating blade coater depends on web tension and blade contour to con-
trol thickness, whereas the knife-over-roll configuration (Fig. 10.5) allows you to set the knife at a
fixed distance from the roll. Modifications of knife contour control coatings of various viscosities
and rheologies exist.
A unique form of spread coater operates by applying an excess of coating and then metering
with a transverse rod helically wrapped with a wire (or rod).The gauge of the wire governs the

Coating 61
thickness of the remaining coating (at constant solids content). A coarse wire gives heavier coat-
ings, while a fine one leaves thinner films.The rod is most often used for thixotropic solutions and
dispersions; dilatant liquids do not perform well with this method.
Application of fluid coatings to a web by spraying is usually accomplished with multiple spray
heads mounted on an oscillating carrier. Mount the spray heads so the patterns overlap, and move
them across the web to lay down a uniform coating.
There are many types of roll coaters available; perhaps the most successful is some version of
the reverse-roll arrangement.The reverse roll is so called because the roll rotates counter to the
substrate travel.This allows you to control coating thickness by adjusting the gap between either
the metering roll or applicator roll or both.The reverse roll coater works best at applying coatings
that are thixotropic or at least Newtonian (chapter 1). Coatings of a dilatant nature generally run at
lower speeds because of the high shear between the applicator roll and the substrate.
In some instances, where both sides of a substrate must be coated, it is best to dip the substrate
directly into the coating and remove the excess to leave the desired thickness.This is achieved by
passing the coated substrate between two rolls or two wire-wound rods. Fusing two-sided coatings
of sticky substances is generally difficult, and production speeds are usually very low.
Air knife coating machines are used for applying water dispersions or an emulsion, where sol-
vent loss and resultant surface skinning is not a problem.By using an arrangement similar to the one
depicted in Figure 13.39, you can apply a smooth, uniform coating.
Fluidized Bed Coating
In fluidized bed coating, the object to be coated is heated and then immersed in a dense-phase air
fluidized bed of powdered plastic; the plastic adheres to the heated object and subsequent heating
provides a smooth, pinhole-free coating.
Spray Coating
Spray coating is used before and after assembly, the latter particularly if the product is already
assembled and has a complex shaped and curved surfaces. Many different types of spray equipment
are in use to handle the different forms of paints.They are classified by their method of atomization
(airless, air, rotary, electrostatic, etc.) and by their deposition technique (electrostatic or nonelec-
trostatic, flame spray, etc.). Spraying techniques may fall into several of these categories. They
range from simple systems with one manual applicator to highly complex, computer-controlled,
automatic systems.They can incorporate hundreds of spray units.Automatic systems may have their
applicators mounted on fixed stands, on reciprocating or rotating machines, on robots, and so on.
Flame spray coating
Flame spray coating consists of blowing a powder through a flame that partially melts the powder
and fuses it as it contacts the substrate.The part’s surface is preheated with the flame, usually to

about 400°F (204°C) when using polyethylene.The usual approach is to coat only a few square
meters at a time so the temperature can be controlled.The flame is then adjusted.When coating is
completed, the powder is shut off and the coating is postheated with the flame. Flame spraying is
particularly useful for coating products with surface areas too large for heating in an oven. Disad-
vantages are the problems associated with an open flame and the need for skilled operators to apply
the coating.
Powder Coating
Powder coating is a solventless system; it does not depend on a sacrificial medium such as a solvent,
but is based on the performance constituents of solidTP orTS materials. It can be a homogeneous
blend of the plastic with fillers and additives in the form of dry, fine particles of a compound similar
to flour.
Advantages of powder coating include minimum air pollution and water contamination,
increased performance with coating,and consequent cost savings.It has many of the same problems
as solution painting.If not properly formulated,the coating may sag (particularly if it is thick),show
poor performance when not completely cured, show imperfections such as craters and pinholes,
and have poor hiding with low film thickness.Various methods are used to apply powder coatings.
Electrostatic Spraying
Electrostatic spraying is based on the fact that most plastic powders are insulators with relatively
high volume resistivity values.Therefore, they accept a charge (positive or negative polarity) and
are attracted to a grounded or oppositely charged object (which is the one being coated).
Coil Coating (Metal Coating)
Coil coating processes involve high speed (at least 500 ft/min) and continuous mechanized proce-
dures for paint coating one or both sides of a coil of sheet metal.Coating equipment,metal cleaning,
and new paint formulations provide ease of formability with environmental durability.The basic
operations in the process involve unwinding steel coil, chemically pretreating steel, reverse roll-
coating paint, baking paint, applying additional coatings in certain processes, cooling coated metal,
inspection, and rewind coil.
The National Coil Coating Association in Cleveland, organized in 1962, has already been very
active in such operations as developing industry standards, exchanging technical information, pre-
paring technical manuals, and keeping records of sales growth.
The first extensive market for this product was for venetian blinds, followed by metal awnings,
metal sidings, automobile trims, light reflectors, luggage, metal doors, and other similar products.

Coating 63
Figure 10.16 Vacuum-ultraviolet radiation effects on stabilized organic coatings.
Figure 10.15 Vacuum-ultraviolet radiation effects on organic coatings.
PROPERTY
Plastic coating materials have been exposed to all kinds of performance tests and environments to
meet the many different requirements that exist in the many different applications.Figures 10.15 to
10.20 show a few properties of coatings when in severe environments.What follows is information
that highlights some of the properties and tests that influence the performance of coatings starting
withTable 10.23 (chapter 22).

Figure 10.18 Relationship between solar absorbance and pigment ratios.
Figure 10.17 Relationship between solar absorbance, total hemispherical emittance, and pigment
ratios.
Corrosion and Chemical Resistance
Corrosion-and chemical-resistant paints are used to protect industrial products and structures
from attack by the weather and corrosive materials.A wide range of protective coatings has been
developed to meet various different service conditions, methods of application, drying schedules,
and other performance and economic requirements. Some of these coatings are used without

Coating 65
Figure 10.20 Effects of vacuum-ultraviolet radiation on pigments.
Figure 10.19 Vacuum-ultraviolet radiation effects on inorganic coatings.
pigment and are based on synthetic resins and rubbers. Others contain special corrosion-inhibiting
pigments; their binders are materials such as drying oils, varnishes, alkyds, and epoxies.
Another group of these coatings is based on bituminous materials.Although they are designed
to provide a protective barrier between the surface to be protected and the corroding elements
or materials, they utilize two different methods of protection. For example, clear coatings and
those based on bituminous materials protect essentially by providing a barrier that is of sufficient
thickness or resistance (or both) to service conditions to prevent the corroding environment from
reaching the protected surface.
However, corrosion-resistant coatings based on drying oils, varnishes, and other products are
quite permeable to water and oxygen.These coatings depend almost entirely on their inhibiting

pigment to control corrosion. In addition, the electrolytic resistance of coatings is an important
factor in their ability to inhibit corrosion.
Many different factors must be considered in the development of a suitable coating system.
In many cases, combinations of corrosion-inhibiting primers obtain the best results and produce
highly resistant finished coats. However, in all cases it has been demonstrated quite clearly that the
paint system must have sufficient thickness to obtain adequate protection. It is generally believed
that the minimum thickness of the paint system should be 5 mils.
Fire Retardant
The majorities of paint binders are organic in nature and hence are inflammable. Incorporating
additives such as chlorine, bromine, nitrogen (bound in particular ways), phosphorus, or silica can
Table 10.23 Plastic coating property guide

Coating 67
reduce the inflammability of organic material. Coatings based on noninflammable binders include
lime washers, cement paints, and silica paints.
Inorganic pigments are generally noninflammable. Antimony trioxides and zinc borates are
particularly effective. Combinations of organic and these inorganic pigments provide fire-retardant
characteristics.
Very few clear fire-retardant coatings are available.They are generally two-part systems using
epoxy or urethane resin.There is a transparent PUR type for use on wood and metal parts such as
walls,ceilings,building fixtures,and furniture.When subjected to fire,it swells,creating an insulating
surface of charred foam that prevents further burning.This is fundamentally a practical application for
what was developed during the KoreanWar as fire walls for use in different military vehicles.
These coating are not sensitive to moisture, as were the previous types. A dry coating can
expand 166 times, or go from 6 mils thickness to 1 in.This system provides a major step forward
in saving lives and property from fire.
In the meantime, this industry continues to target the development of a fire-retardant coating
that does not cause the usual loss in other properties and does not significantly increase cost. Of
course the real push for these coatings will occur if state and local governments adopt more strin-
gent building codes.
Intumescent Coating
Intumescent coatings, or coatings that bubble and foam to form a thermal insulation, have been
used for many years. Such coatings cannot otherwise be differentiated from conventional products.
Thereupon, however, they decompose to form a thick, nonflammable, multicellular, and insulative
barrier over the surface on which they are applied.This insulative foam is a very effective insulation
that maintains the temperature of a flammable or heat-distortable substrate below its ignition or
distortion point. It also restricts the flow of air (oxygen) from the substrate fuel.
It is estimated that millions of gallons of alkyd and latex-emulsion intumescent paints are used
annually. These coatings provide the most effective fire-resistant system available, but originally
they were deficient in paint properties. Since, historically, the intumescence-producing chemicals
were quite soluble in water, coatings based on those chemicals did not meet the can stability, ease
of application, environmental resistance, or aesthetic appeal required of a good protective coating.
In time to meet market requirements, Monsanto Company developed a new water-resistant,
phosphorus-based intumescence catalyst.This new commercially available product, Phos-Chek P/30,
can be incorporated (with other water-insoluble reagents) into water-resistant intumescent coatings
of either the alkyd or latex emulsion type.These intumescent coatings, formulated according to the
manufacturer’s recommendations, are described as equivalent to conventional products in coating
properties.They also provide permanent fire resistance to the substrate on which they are applied.

Heat Resistant
Different types of coatings are available to meet the different heat resistant environments.There are
coatings that can be exposed to high temperature intermittently.The film is subjected to mechani-
cal forces by differential expansion and contraction. Limiting factors involve breaking the bond to
the substrate and the effect at elevated temperatures of oxygen attack on the coatings (when in an
oxygen-rich atmosphere).
Inorganic polymers and semiorganic polymers are the binders that show the best heat resis-
tance. Extensive research and development have been undertaken to study polymers containing
boron, nitrogen, phosphorus, silicon, and so on.The esters of silicon, titanium and the silicones are
examples of binders that are suitable for continuous use at temperatures above 150°F (66°C). For
the best practical results, they are pigmented with leafing aluminum.This composite protects the
organic part of the binder from oxygen attack and also forms a metal-ceramic complex.
For temperatures up to 150°F, many binders may be used to obtain a useful life. Short oil phe-
nolic varnishes, oxidized rubber, and melamine/alkyd resin stoving finishes (where the alkyd is a
saturated fatty acid/isophthalic acid type) have been used in various coating systems.
Thermal Control
Since 1960, passive thermal control of space vehicles and their components has emerged as an area
of increasing importance among the space sciences.This area is destined to achieve greater stature
as our ventures into space become longer in duration and complexity. Indicative of this importance
is the research now being devoted to space exploration.
In contrast to active thermal control, passive thermal control offered the advantages of no
moving parts, hence the absence of mechanical failure, and a considerable weight savings.The fun-
damental parameters in controlling the space vehicle’s temperature by passive means are the optical
characteristics of the surface of the spacecraft, that is, the solar absorptance and the emittance.
However, in order to function as a thermal control surface, a coating must be optically stable in
the space environment, especially with respect to ultraviolet radiation, particulate radiation, high
vacuum, and temperature. In addition, the properties of the coating, such as flexibility, adhesion,
ease of application and ability to air-cure could not be overlooked.
The major effort over the past several years has thus been directed toward the preparation of
organic and inorganic coatings with desirable temperature-control properties. At the same time,
researchers pursued a critical evaluation of the factors of the space environment and performed
laboratory research involving the effects of these factors on the optical and physical properties on
coatings and coating materials.
In an attempt to simulate the environment of outer space, the research worker was faced with
many unknown factors.The definition of the space environment has been and is presently a major
area of scientific research in itself. This lack of overall knowledge, in addition to the economics
involved in simulating the space environment in its entirety, translated into compromises in the
exposure chambers.

Coating 69
Although white organic coatings have been shown to degrade,primarily by ultraviolet radiation,
their flexibility, adhesion, ease of application, air-drying characteristics, and high emittance have
persuaded researchers to spend considerable time and effort studying them. Inorganic coatings,
however, offered the promise of stability to ultraviolet radiation and high vacuum, but presented
problems in adhesion and flexibility and involved heat cures.The effects of particulate radiation,
although not forgotten, remained somewhat in the background.
Organic formulations have been developed with air cure properties and optical properties.Fig-
ure 10.15 shows typical coatings. Pigment research, with regards to stability, compatibility, index
of refraction, particle size, purity, and other properties, has shown ZnO,TiO, and ZnS to offer the
most promise.The most stable vehicles in combination with these pigments involved the silicones
and their variations, acrylics, silicone alkyds, and certain fluorocarbon polymers.
With the synthesis of colorless ultraviolet radiation absorbers, such as the derivatives of
osmocene and ruthenocene, it has been possible to enhance the stability of otherwise borderline
acceptable thermal control coatings to the point where these coatings become candidate materials
(Fig. 10.16).The derivatives of ferrocene, although enhancing the stability of certain white coat-
ings, gave a high initial performance due to its inherent red coloration.The derivatives of osmocene
and ruthenocene, however, were white to light yellow.
The controlled addition of pigment to both basic white and black formulations has provided
design engineers with a series of coatings with a wide range of performances for specific applica-
tions.These formulations are shown in Figures 10.17 and 10.18.
Electrical Insulating
A new and revolutionary idea has been explored for the application of enamels to copper (or alu-
minum, etc.) magnet wire (Fig. 10.12). It is electrodeposition, a process of coating copper wire in
an aqueous solution by an electric current. In this method, an organic resin particle is dispersed in
water in such a manner that it has an electrical charge.Then, under the influence of an electrical
field, it is attracted to a positive electrode, the copper-wire anode, and deposited onto it.
This method has been used for years in the electroplating of metals. It was not until the resin
chemist was able to formulate superior water-soluble, or water-dispersible, resins, that these basic
principles could be applied to the coating industry.
The process of electrodeposition produces an unusual phenomenon.The resin plays a dual role
in the process.The material is a conductor at one point, and a few minutes later it is an insulator.
The objective of the program was to resolve these two paradoxical processes. Perhaps it might
appear that with this approach, in which the insulator is water soluble during its processing, the
coating would still have an affinity for water. However, the coated enamel has lost its water solubil-
ity through the baking cycle during which it has become an insoluble,TS resin. Correct formulating
principles permit the resin to perform this dual role.
The principal advantages of electrodeposition over conventional methods are as follows:

1. Faster production rates. Production of coated wire can be increased four to six times
per hour. Only one passage of the wire through the dip tank is required. For example,
a processing wire mill will have to run #18AWG copper magnet wire through the
dip tank only one time—rather than four to six times—to obtain heavy build.
2. Superior properties through formulation of higher MW materials.The resin chemist will
be able to develop unusually long chain polymers because water is used in the system.
3. Elimination of offensive odors, especially cresylic acid fumes that are common in
cities.
4. Complete and uniform coverage. In electrodeposition, the charged negative particles
are attracted to positive metal surfaces.This attraction will continue until the entire
metal surface is covered.
The phenomena of electrodeposition,as applied to a protective coating application method,are
complex. Although the method employs theories established many years ago, the practical appli-
cation of these principles has introduced variables that complicate the deposition.To accomplish
deposition by this method, it is necessary to have a water-soluble resin (or water-dispersible resin
or emulsion) and a dip tank with two electrodes.When the current is turned on,the following reac-
tions occur: electroysis, electrophoresis, electrocoagulation, and electroosmosis. All four of these
reactions usually occur simultaneously during the deposition of a resin.They play an important role
in the correct application of the resin to the wire.
SIMULATED SERVICE TESTS
Many different service tests have been used throughout the centuries, and more tests will be devel-
oped in the future.This way of life is directly related to progress. Of course the real test is when
parts are in use. Many of the laboratory tests described throughout this chapter and book will
provide useful ideas for conducting simulated service tests.This section presents a review on how
to evaluate coated fabrics. Different tests can be used to evaluate elastomer-coated fabrics.The fol-
lowing typical tests provide brief and limited examples of information on testing procedures.
Abrasion Resistance
Abrasion is of primary importance with materials that are exposed to much abrasion, such as truck
covers.Tests should be conducted after exposure to the liquid in which it will operate.Test values
have only relative merit; projection of results to service can be difficult without experience, since
many factors affect performance. Examples of tests follow.
In the Taber Abrasion Test, abrasion wheels and weights are used in various combinations to
abrade one or both sides of a fabric.Values are reported in numbers of cycles needed to achieve
either first exposure of the base fabric or to cause initial tearing. In another method, the abrader

Coating 71
is run for a number of given cycles, and then the coating’s weight loss is measured.A less accurate
method involves judging the appearance of fabric after a given number of cycles.
In the DuPont ScrubTest, a specimen is vigorously scrubbed against itself between two mov-
ing jaws.The number of cycles needed to first expose the base fabric is reported.Values are usually
determined for each side and for warp and filling direction.Visual inspection after a given number
of cycles is not as accurate.
In theWysenbackTest, also called the oscillatory cylinder test, the fabric is subjected to unidi-
rectional rubbing action under known conditions of pressure, tension, and abrasive action.To test
specimens,they are placed in contact with an oscillating cylinder covered with an abrasive material.
Values are reported for loss of breaking strength after 250 cycles of continuous abrasion under a 2
lb load (ASTM D1175).
Adhesion
Adhesion is particularly important in applications where a fabric is exposed to a great amount of
flexing, pressure, and stretching. For fabrics with several plies, adhesion between plies should be
tested. It is a particularly critical property in such products as life rafts, life vests, and other bonded
inflatables.A testing example is the Scott test method, in which adhesion is tested by peeling coat-
ing from the base fabric, or by peeling two plies apart.A 2 in wide sample is inserted in jaws that
separate at a given speed, most frequently 2 ipm or 12 ipm. Results are expressed in lb/in of width
required to peel coating and fabric or two plies apart (ASTM D751).
Accelerated Aging in Hot Air
This is a useful measure of service life at atmospheric temperatures, and is particularly important
for fabrics that must perform at elevated temperatures, such as automotive and heating equipment.
The following paragraphs describe examples of the tests used.
Hot-air aging
Samples are placed in a thermostatically controlled air-circulating oven and aged for specified tem-
peratures and times. Fabrics that are not expected to perform in elevated temperatures are usually
aged for 72 hours at 160°F (71°C). Fabrics used in automotive applications are aged for 72 hours
at 200°F to 300°F (93°C to 149°C). If fabrics will be exposed to oils or other fluids during actual
service, samples are immersed in suitable test fluids.
Aging in stop-and-go applications
Aging tests are interrupted and fabrics are allowed to dry between hot air tests.After aging,proper-
ties are compared with those taken before aging (ASTM D573).

Accelerated aging in oxygen
This testing establishes the behavior of fabrics that are exposed to air and sunshine in critical appli-
cations, such as life rafts, tarpaulins, and radome covers. In the oxygen bomb test, samples are
placed in a bomb for a specified period of time at a temperature of 160°F and 300 psi (2 MPa) of
oxygen pressure. After aging, most important physical properties are tested and checked against
values obtained before aging (ASTM D52).
Blocking
This testing shows the tendency of certain elastomers, including natural rubber, to adhere to them-
selves. In a blocking test, a sample is folded and put under a 4 lb weight in an oven at 180°F (82°C)
for 39 min. After cooling, the sample is unfolded and examined for adherence or peeling of the
coating (ASTM D 1893).
Burst Strength
This is an important guide in applications in which a fabric is exposed to high and sudden pressures,
such as in gas regulators and controls. In the Mullen test, a sample is clamped across the orifice of a
Mullen tester with a rubber diaphragm. Power is applied, and the pressure at which rupture occurs
is recorded in gross and net psi values (ASTM D 751).
Compression Set
This measure of the permanent deformation of a fabric exposed to constant pressure or deflec-
tion can be important, particularly with coated fabric diaphragm assemblies in units with bolts or
crimps.There are the test methods in which a sample is held under either constant load (method
A) or constant deflection (method B) for a specified length of time in a specified constant tempera-
ture.The residual decrease in thickness, either a percentage of original thickness (method A) or a
percentage of deflection under load (method B), is reported as the compression set.An interval of
at least one week between removing the load and measuring the residual decrease in thickness or
deflection is necessary to evaluate the permanent set (ASTM D 395).
Curl
Curl is an inconvenience in assembly, especially when using automatic assembly equipment. Fabrics
that normally have the same coating on both sides should not curl; however, materials coated on
one side almost always curl.There is a test method where a disc with a diameter of 2¼ in is allowed
to rest for 24 hours at 70°F (21°C) with the side that shows the tendency to curl facing up.The
distance from tabletop to the highest point of curl is reported as curl value.A curl of ¼ in or more
is usually considered excessive for a diaphragm assembly.

Coating 73
Elongation
Elongation without rupture is desirable in diaphragms that pulse with a long stroke.In other devices
in which dimensional stability is of utmost importance, such as metering devices, elongation of a
fabric is undesirable.Test method samples are stretched in a Scott tester until they rupture.The
amount of stretching that occurs between benchmarks at the time of rupture is the ultimate elon-
gation of the fabric.Values are expressed as percentages of the original distance between the marks
(ASTM D 751).
Flame Resistance, Vertical
A guide to flame resistance is important with any coated fabric used where a fire hazard exists. Sev-
eral flame tests (UL) are available of which the severest and most widely used is vertical flame test.
In this test, a sample measuring 2¾ in × 12 in is clamped between metal flanges and suspended in
a metal cabinet to shield it from drafts.A flame of a standard size and a standard intensity is placed
under the sample for 12 seconds.The burner is then removed without opening the cabinet.Three
values are usually measured: (1) the length of time the flame continues to burn after the removal of
the burner, (2) the length of time the glow continues, and (3) the char length, expressed as distance
to which a charred sample will tear when subjected to a specified load.
Flexibility
This property is important in many lightweight fabric diaphragms used in delicate sensing devices.
A testing machine takes one end of 1 × 3 in sample and places it in a clamp that will rotate the
sample up to 90°.The other end of the sample actuates a balanced arm that gives readings up to
100 units.The stiffest samples give the highest readings; weights can be added to balance very stiff
samples.Values (expressed in weights plus units) can be read at various degrees of rotation of the
sample. Most commonly, the value at 30° rotation is read.
There is also a test in which a strip measuring 1¾ in wide is placed between two rollers with 1
in diameters held together by spring pressure. One of the rollers is slowly rotated.The overhanging
sample is adjusted until it falls over in both directions of rotation when the framework is rotated clock-
wise and counterclockwise.The length of the overhanging portion, in mm, is the flexibility value.
Hardness
A measure of hardness is important in such products as rubber offset blankets.The hardness of a
coating is usually measured before the coating material is applied to the base fabric.The popular
Shore durometer is one method of testing. It usually gives valid readings only with unsupported
elastomers of at least ¼ in thickness. On coated fabrics it does not produce reliable, absolute values
because instrument registers some of the hardness of the base fabric.

A Shore durometer measures resistance of the sample to penetration by an indenter at the
point of an instrument, which extends 0.1 in beyond the surface of the presser foot.The durom-
eter reads 0 when the indenter is fully extended and 100 when it is pressed to a flat piece of plate
glass; thus a high value indicates a hard sample. Coated fabric, to be hard, should give a reading
of about 70.
Hydrostatic Resistance
A measure of this characteristic is useful for coated fabric intended for rainproof applications.The
Mullen test is for high water-pressure resistance.A sample is clamped between jaws with circular
openings and water pressure is raised until the first drop of water passes through sample. Pressure
at this point is expressed in MPa (psi;ASTM D 751).
The Suter test is used for medium or low water-pressure resistance (up to 14 kPa [2 psi]); it
employs a rising water column placed over a test sample. Resistance is reported as the height, in
cm, of the column at which pressure causes the first drop of water to penetrate the sample.
There is an impact spray test for low water-pressure resistance. A fabric sample is bombarded
with a spray of water from a specified height, usually a column measuring 0.9 m (3 ft).The water that
passes through a sample of a standard area within a specified time is accumulated in a 6 × 6 in blotter
mounted behind fabric.The increase of weight, in mg, of the blotter is the spray penetration value.
Low Temperature Cracking
This guide is important with fabrics that must perform outdoors in cold climates, such as gas meter
and regulator diaphragms.Test temperatures of –40°F and –67°F (–40°C and 19°C) are commonly
used. In the bent loop and hammer test, a weight is dropped on a bent sample until it cracks.The
test measure is given as the number of cycles to failure.
In the bar test, two samples measuring 1 in wide are threaded under a bar with 1/8 in diameter
that forms the hinge between a center plate and a longer plate on each end.The end plates are lifted
and then allowed to drop on the center plate, flexing the fabric samples around the bar until they
crack.The measure of resistance is the number of cycles to failure.
In fold and roll tests, a 10 lb (4.5 kg) roller is rolled over a sample that is first folded in one
direction and then folded in the opposite direction.The test is continued until the sample cracks,
and the number of cycles to failure is used as the measure of resistance. Other tests include ASTM
D 736,ASTM D 746,ASTM D 797, andASTM D 1053.
Modulus
A coating with a low modulus of elasticity is desirable in highly flexible coated fabric applications,
such as rapidly pulsating diaphragms. A modulus can be measured satisfactorily only before the
elastomer is applied to the base fabric. It is usually measured by the stress in MPa (psi) at any given
elongation; most commonly used values are obtained at 300% elongation.

Coating 75
Gas Permeability
Permeability measurements of gases are important for coated fabrics used in life vests and other
inflatable products.They are also vital for gas meter and regulator diaphragms. In the Cambridge
permeameter test,samples are tested in an apparatus using hydrogen gas. Tests are usually con-
ducted for 2 minutes, and the instrument converts readings into values expressed in 1/m2/24 h.
For life vests and rafts,a reading of 51/m2/24 h is acceptable.Results can be converted into equiva-
lent values for helium, carbon dioxide, or other gases by using factors recommended by the Bureau
of Standards (ASTM D 815).
Liquid Permeability
Liquid permeability measurements are significant for fabrics used as fuel containers or vapor traps,
such as breather balloons.In a test,a specified amount of test liquid is placed in a cup or jar of specified
dimensions; the fabric sample is then placed over the cup or jar and sealed.After allowing the sample
to reach equilibrium, the cup or jar is weighed accurately and then inverted and allowed to stand for
a specified period,after which it is weighed again.Weight loss is calculated generally in fl oz/ft2/24 h.
pH Value
The pH value of a coating is useful to know in applications where the coating comes in contact
with metal parts. Normally, the coating should have a neutral pH.The test method uses the fabric
or coating cut into small pieces and placed in distilled water for 3 hours.The pH is then measured
with a standard meter.A reading of 7 represents neutrality; 7 shows acidity; 7 shows alkalinity
(Tables 10.24 and 10.25).
Resiliency
Resiliency can be an important index in many applications, such as rubber-coated offset print-
ing blankets.The Bashore resiliometer test has a bob dropped vertically onto a fabric sample at
the base of an instrument.The distance that the bob bounces back after impact is reported as a
percentage of the original height from which it was dropped. It should be remembered that the
resiliometer records the combined resiliency of the coating and base fabric. If a reading of the
elastomer coating alone is wanted, then a fairly thick sample of elastomer coating material must
be tested before the coating application.
Stretch
Temporary stretch and permanent residual stretch are undesirable in a coated fabric that requires
great accuracy, such as a metering diaphragm or an offset printing blanket.The test method uses a
10 in length (accurate to the nearest 0.01 in.) that is marked off on a 1 × 12 in sample.A clamp is

Table 10.24 Examples of acids and bases pH

Coating 77
Table 10.25 Color indicators of acids and bases pH

applied to each end, and a 50 lb (22.5 kg) weight is suspended from one end for 10 minutes.The
amount that the fabric stretches during testing is reported as temporary stretch and is expressed
in a percentage of the original 10 in length. If a stretch remains after removing the weight, it is
reported as permanent residual stress.
Swelling
A test for swelling is required for any coated fabric that may come in contact with oils, solvents, or
other liquids during use.There is a test method where oblong samples are immersed in a graduated
cylinder containing alcohol to measure their volume.The samples are then dried and immersed
in the test medium for a specified period under a specific temperature. Following exposure, the
samples are removed and their volume is measured again.The increase in volume from swelling is
recorded as percentage of the original volume.
Alcohol is used to measure the fabric volume because it is clear, does not cause swelling, and
permits the sample to sink.Toluol is the most frequently used swelling medium because its swelling
properties match those of many media. However, several other fluids are available for determining
swelling characteristics.
Many brands of gasolines, oils, and other fluids have proprietary formula ingredients. Dust,
fumes, and temperature, among other factors, may affect the composition of the fluids.Therefore,
in critical applications such as fuel and brake systems, extensive life tests should be conducted with
fabrics under the expected operating conditions.
If the coated fabric has to perform at elevated temperatures, then swelling tests are run at the
expected temperatures. In some cases, the percentage increase in gauge or weight, rather than the
change in volume, is measured.
Tear Strength
Fabric that will be stressed should be tested for tear strength.The Pendulum method (Elmendorf)
test uses a 2.5 × 4 in fabric sample held between two clamps at the base of an Elmendorf instrument.
The sample is nicked with a knife attachment, and then a pendulum is released and falls through the
sample. The pendulum carries a circumferential scale that indicates the force required to tear the
specimen. Scale readings can he multiplied by appropriate factors to give results in pounds or grams.
Values are determined for both the warp and filling direction of the fabric (ASTM 751).
In theTongue method (strip), a cut is made at the center of the 3 in edge of a 3 × 8 in sample.
The two 1½ in ends are then placed in two jaws of a tester.The jaws are separated at a speed of 12
ipm.A recorder records tear as a high point on a chart.The average of five tests is reported as tear
strength in lb or MPa.Values are determined for both warp and filling direction.
In the Trapezoid method, a trapezoidal sample, 6 in long on one side and 3 in long on the
opposite parallel edge, is given a small cut at the center of the 3 in edge.The nonparallel edges

Coating 79
are clamped into the jaws of a tester, and the sample is torn apart at a speed of 12 ipm. Using the
recorder, a researcher notes the average of five high points as tear strength in MPa (lb).
Tensile Strength
The coated fabric manufacturer normally supplies a standard tensile strength value by the grab
method in both warp and filling directions.The Grab method uses 4 × 6 in fabric samples that are
inserted in 1 × 1 in jaws of a tester.The jaws, 3 in apart at the start, are separated at 12 ipm.Values
are reported in pounds per inch.To obtain accurate results, extreme care must be used to obtain
proper alignment of the yarns in the jaws (ASTM D 751).
In a cut-strip method, strips measuring 1 × 6 in are cut in both the warp and fill directions. In
turn the yarns are carefully aligned in the dies. Samples are ruptured in a tester; values are recorded
in lb-in (ASTM D 751).
Thickness
In many applications, it is essential to have uniform thickness over the entire surface of a coated
fabric.Test methods using a gauge with 0.001 in graduations can be employed for thickness mea-
surements. Since the gauge uses a deadweight rather than a spring gauge, great care must be taken
to apply an absolutely straight load to obtain accurate readings.
Wicking
In some critical applications, it is essential to measure the air or gas leakage through pinholes or
through internally exposed edges of vent holes into the fabric from where it bleeds to fabric edges.
Coated fabric diaphragms performing in critical applications, such as air controls, must be proofed
against wicking. In a wicking test, a coated fabric sample is clamped into a test jig immersed in
water. Flange clamping pressure must be sufficient to prevent loss of gas between the sample and
the flanges, but not so high as to impede the flow of gas through the edges.
After immersing the jig in water, gas pressure is applied to the jig, and pressure is gradually
raised until bubbles are visible at the outer edge of the sample. Pressures are usually raised at
increments of 10 psi up to a maximum of 100 psi.The pressure at which initial leakage occurs is
recorded, and the next lowest pressure is defined as the antiwicking value, or the pressure up to
which the fabric will perform without wicking.
Weathering
With any coated fabric that is to be used outdoors, it is very useful to have a guide to weather-
ing properties before the fabric is placed in service.To obtain accelerated results, weatherometer
equipment can be used to simulate rain and sunshine by use of water spray and carbon arc. Both
physical tests and visual examination can be used to indicate the deterioration that occurs after a

specified period of time. Military specifications frequently stipulate the minimum physical test
values that must be met after a specified time of exposure. Comparative evaluations can provide an
indication of the weather resistance of different fabrics (ASTM D750).
SOLVENT AND COATING
Solvent Composition in Coating
The usual definition of solvents describes them as fluids having a maximum boiling point of 482°F
(250°C) and able to dissolve other components of coatings, especially binders.They evaporate under
drying conditions when paint films are formed. Solvents must not react with the coated product.The
composition of coatings (paints, varnishes, etc.) is determined by application requirements, drying
temperature, and drying time. Depending on the properties of paints and varnishes, different mix-
tures of solvents are added.Table 10.26 provides classifications and definitions of solvents (374).
The functions and properties of solvents in coatings are as follows:
1. Dissolve several components, especially binders.
2. Influence and control paint viscosity.
3. Wet pigments, thus influencing solubility, enabling hydrogen bonding by solvents,
and preventing the separation of pigments.
4. Influence and control flow properties (e.g., butyl acetate, butanol, and glycol ethers).
5. Influence skin formation.The aim is to produce a homogeneous cure when, for
example, the paint or varnish film hardens without the formation of a stable surface
film during the drying period.The correct composition of the solvent will avoid
trapping solvents under the surface film.
6. Influence the drying process, thus influencing the acceleration by low boilers or the
production of a flawless surface by medium and high boilers (e.g., the chemical and
physical drying processes).
7. Influence surface tension (e.g., increase by rapid evaporation of solvents).
8. Influence mechanical properties of paints (e.g., adhesion properties).
9. Influence blushing or blooming of paints by preventing the absorption of condensed
water by various solvents (e.g., ethanol and glycol ether).
10. Influence gloss (e.g., improvement with high boilers).
11. Prevent defects particularly in varnish coating (e.g., background wetting).
12. Influence electrostatic properties (e.g., spray painting).
13. Influence defined surface properties (e.g., create structural changes).
14. Influence durability of paints and varnishes.
15. Influence product suitability (e.g., spraying and dipping lacquers that need to dry at
room temperature).

Coating 81
Table 10.26 Classifications and definitions of solvents

Table 10.26 Classifications and definitions of solvents (continued)

Coating 83
In addition to their effect on performance and properties solvents interact with other compo-
nents in paints and varnishes in significant ways. Interactions between binders and solvents in paints
and varnishes are very important.With the aid of solubility parameters, solvents or mixtures of sol-
vents that produce the required properties may be selected.The influence extends to the dissolving
of binders, the reduction of paint viscosity, pigment wetting, and so on.
Optimized dissolving of binders can be achieved by selecting the appropriate solvent mixtures,
in which the density approaches that of the binder solubility range. Nevertheless, the selection of an
optimized solvent mixture is difficult because there are conflicting requirements and outcomes. In
one aspect,the chemical nature of the solvents should be similar to those of the binder to improve the
flow. In another aspect, the solubility and hydrogen-bonding abilities of the solvents should be at the
edge of the binder solubility range,because this results in rapid drying with a low retention of solvents.
Solvent and Solvent-Free Coatings
Solvent composition is an important aspect in classifying paints and varnishes. A list of the main
groups of these coatings follows:
1. Solvent products.These products contain solvents of various mixtures, types, and
concentrations depending on the properties desired (e.g., application method, surface
film, or skin formation). Solvents are normally the main components of these products.
Table 10.26 Classifications and definitions of solvents (continued)

2. Solvent-reduced products.These contain solvents in lower concentrations compared
to conventional products and thus a higher content of solids.The main groups of
solvent-reduced paints are medium solid contents (55% to 65% solids) and high solid
contents (60% to 80% solids).
3. Waterborne coatings.This group contains deionized water as a dispersing agent.
Normally cosolvents are added (up to 25%).The term “waterborne coatings” is
mainly applied to industrial coating materials, which differ from silicate colors,
wood-preservative varnishes, and emulsion paints.
4. Solvent-free products.The products of this group are produced and applied without
organic solvents.They include powder coatings, radiation curing systems, and
solvent-free water coating (without cosolvents).
The use of paints and varnishes containing high solvent concentrations is becoming less com-
mon; solvent-reduced products, waterborne coatings, and solvent-free products are applied more
often. Whereas environmental and health-related concerns call for the reduction of solvents in
paints and varnish products, qualitative aspects still demand the use of solvents in some fields of
application.
Solvent-reduced products have achieved the same qualitative properties as solvent-containing
products (e.g., application properties, periods of guarantee, limited costs, loading capacities, sur-
face properties). Solvent-reduced or solvent-free varnish products have been produced with high
quality (e.g., durable, good application properties) and limited costs. In some fields of application,
such as waterborne coatings, high solids in varnish coatings of vehicles, a lot of developmental work
has been done.
Additionally, other components in varnishes apart from solvents or modifications of appli-
cation techniques can improve the properties of solvent-reduced paint and varnish products.
Nevertheless, a wide rage of quality exists in paints and varnish products that are offered com-
mercially and, in some cases (e.g., film-forming processes, processability, corrosion protection,
purification, special applications, or wood preservation), solvent-based products are still pre-
ferred. In the field of wood preservation especially, solvent-based products (alkyd resins) are
used because of some technical advantages (e.g., more solid surfaces), but alternative high solid
systems are available.
Emission
Solvents are usually the most significant emission products coming from building materials and
interior furnishings. All painted products are potential sources of emission. Even the so-called
“bio” paints or natural paints emit various substances. Examples of these include mineral varnishes,
natural oils, and even synthetic terpene-like compounds. Depending on the products and the com-
ponents that make them up, the following various parameters can determine the emissions and
behavior of solvents in ambient air from paints and varnishes (374):

Coating 85
1. Emission of solvents during the film-formation stage.The emission rate is directly
proportional to theVOC concentrations in the product and inversely proportional to
the film thickness (first order of kinetics).When the film has completely formed, the
emission is controlled by a diffusion process, and the emission rate is now inversely
proportional to the square of the film thickness.
2. Application of the paints and varnishes, methods of application of the paint or varnish
(e.g., speed of application of the paint).
3. Characteristics of solvents in paints and varnishes (e.g., volatility or the boiling
point, dynamic characteristics of evaporation and concentrations). Substances
that have a low boiling point evaporate fast, mostly during application, and cause
a rapid skin formation.Thus the risk of exposure is mainly with the painters.
Medium boilers allow the surface to remain open for a while (evaporation of
volatile products).The evaporation of substances with a high boiling point is slow,
taking several weeks or months after application; as a result, a building’s occupants
may be exposed to the substances.
4. Characteristics of other compounds in paints and varnishes (e.g., relationship of
binders to solvents, possible reactions between solvents and other compounds).
5. Characteristics of surfaces that have been painted (e.g., area, structure of surface).
6. Characteristics of emission processes (e.g., diffusion), dynamics of emissions
(constant of evaporation), interrelations (e.g., diffusion and back diffusion).
The quantitative assessment of emission processes can be described with various models.The
usefulness of these models differs. Some models describe these processes very well, as proven by
various experiments or measurements (e.g., test chambers). Basic equations that describe emission
processes are shown in Table 10.27. An emission of solvents from a varnish system occurs in the
course of a varnish’s life cycle in several different locations, as shown in Figure 10.21.
The emission processes of solvents from paints and varnishes can be divided into two phases:
1. Emissions during application of paints, which deals with complex interrelations
dependent on various parameters
2. Emissions after the application process, the course of which is governed by complex
emission processes that are dependent on various parameters (e.g., film formation,
surface area)
Most solvent products, especially organic solvents and some additives, emitted from paints
and varnishes areVOCs.The largest components ofVOCs are solvents (e.g., aliphatic and aromatic
hydrocarbons, alcohols, amines, acids, aldehydes, esters, ketones, and terpenes). The definition
of VOCs varies. A standard definition is published by European Committee for Standardization
(CEN):VOCs are any organic liquids and/or solids that evaporate spontaneously at the prevailing

Table 10.27 Examples of basic calculations of VOC-emissions during applications of emulsion paints

Coating 87
temperature and pressure of the atmosphere.VOC content (VOCC) is defined as the mass of the
VOCs in a coating material, as determined under specific conditions.
Clean Air Act
Almost all solvents are VOCs and hazardous air pollutants (HAPs), and their evaporation creates
environmental problems that have become the focus of many domestic and international regula-
tions and initiatives.AVOC solvent is defined by the Environmental ProtectionAgency (EPA) as any
compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides
or carbonates, and ammonium carbonate, which is emitted or evaporated into the atmosphere.
In recent years,the US Congress and the EPA have recognized the need to address environmen-
tal problems from a more holistic approach, considering multimedia and innovative environmental
management strategies.Thus various Clean Air Act programs and project initiatives, which have
proven to be extremely successful, have emerged. Many of them encourage voluntary industry
participation and do not take the old command-and-control approach. Details of the CleanAirAct
are reviewed in chapter 26.
SOLVENT SUBSTITUTION
In the past few decades, substitution of solvents by safer products and processes has been occurring.
Effective utilization of supercritical fluids has been developed for high-value-added differentiated
products.
A new wave of second-generation supercritical technologies has started to emerge, creating
new roles for dense gases. “Supercritical” refers to the state of matter in which the temperature
and pressure of a single-component fluid are above the critical point at which the phase boundaries
Figure 10.21 Emission of VOCs in the life cycle of a varnish.
Emission from
Plants
VOC in mg/m3
or kg/h respectively
Varnish System
VOC in % or g/kg
or g/l respectively
Inﬂuence from
Surrounding Air on
the Varnish Processor
VOC in µg/m3
or ng/m3
Emission from
the Surface
VOC in µg/m3
Emission at the
Workplace
VOC in mg/m3
Inﬂuence
on Interior Air
at the Users Place
VOC in µg/m3
or ng/m3

diminish.A portfolio of chemical and physical operations carried out in the vicinity of this region
defines supercritical fluid technology (SFT).
The pressure–temperature–volume (PVT) behavior of a substance can be best depicted by
pressure–-temperature and pressure–density (volume) projections, as shown in Figure 10.22.The
pressure–temperature diagram identifies the supercritical fluid region, alternative separation tech-
niques that involve phase transition including the associated phase boundaries, and the fact that
an isotherm below critical (AB; Fig. 10.22) involves phase transition while one above (A′B′) does
not. Pressure–density projections illustrate tunability of the solvent density at supercritical condi-
tions (A′B′), and again the continuity of the isotherm that does not encounter any phase transition.
The aforementioned behavior is for a pure-component solvent.The critical properties of various
organic and inorganic substances are shown inTable 10.28.
Figure 10.22 Pressure-temperature and pressure-density behavior of matter.

Coating 89
Table 10.28 Critical properties of solvents

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