![76
COMPOUNDS■
Grivory HT3 is a completely new PPA
polymer that is based on long-chain di-
amines. It exhibits important character-
istics which are further improved com-
pared to those of Grivory HT1 and HT2.
These give it access to fields of applica-
tion from which polyphthalamides have
so far been excluded.
Reduced Moisture Uptake
Until now, polyamides were limited by
the fact that moisture uptake seriously af-
fected material properties.While it is true
that moisture uptake made them
tougher, stiffness and strength were sig-
nificantly reduced. By their nature,
polyphthalamides also absorb moisture,
but to a much lesser degree and much
more slowly. In the case of Grivory HT3,
it has been possible to markedly reduce
moisture uptake to 50% of that of
Grivory HT1. The consequence is that
the new material exhibits exceptional di-
mensional stability and very little ten-
dency to creep.Its physical properties are
essentially unaffected by moisture in the
surroundings.
The long-chain diamines in the poly-
mer chain provide increased hydrolysis
resistance.Thisisclearlydemonstratedby
the extended half-value time after storage
in a water/glycol mixture at 135°C. Elon-
gation at break and tensile stress at break
for Grivory HT3 drop to half their initial
values only after 1,800 h (elongation at
break) and 2,300 h (tensile stress at
break). This corresponds to an increase
inthehalf-valuetimesof 80and50%over
those of the already hydrolysis-resistant
Grivory HT1 GF50 grade (Fig. 1).
With its outstanding elongation and
toughness, Grivory HT3 contradicts the
prevailing opinion that PPA may indeed
be very stiff but is also rather brittle.Even
when highly reinforced,Grivory HT3 is a
tough material with high elongation at
break. As are all polyphthalamides, it is
extremely chemical-resistant and it has
been possible to further improve the per-
formance in hot oil (Fig. 2).
At Home in All Market Segments
Grivory HT is accepted in many applica-
tions encountered in daily life and has
been recognized as a metal replacement
for years. It allows cost-effective produc-
tion of lightweight parts that can with-
standhighmechanical loads –amajorre-
quirement for automotive components.
Its property profile is also appreciated in
this segment for other reasons. The very
good hydrolysis resistance and dimen-
sional stability benefits components that
are in continuous contact with coolants.
Theseincludewaterpumps,radiatorcaps
and expansion tanks. In combination
with exceptionally low permeation, the
goodchemicalresistanceandhightough-
ness predestine Grivory HT3 as a materi-
al for highly stressed connectors in fluid-
conducting systems (Fig. 3).
The electronics industry relies in-
creasingly on miniaturization. Compo-
nents are becoming smaller and smaller
and more complex.At the same time,re-
quirements regarding performance un-
der extreme temperatures and repro-
ducibility are becoming more demand-
ing. Flame retardance is another essen-
tial requirement. Grivory HT3 employs
a halogen and phosphorus-free flame re-
tardant that satisfies the WEEE and
RoHS requirements. It also offers major
benefits during the production process
itself. The halogen and phosphor-free
PPA products on the market to date have
been extremely corrosive when it comes
to barrels, screws and non-return valves
of injection molding machines. Accord-
ingly, a great deal of attention was de-
voted to this aspect during development.
Grivory HT3 is significantly less corro-
sive than previous halogen and phos-
phorus-free flame-retardant polyph-
thalamides on the market. This proper-
ty in particular makes it a favorite inAsia
for the manufacture of connectors. The
first mobile phones with connectors
made of Grivory HT3 are currently be-
ing shipped.
As in the automotive industry, low
moisture uptake and high dimensional
stability play an important role in the
electronics sector. Here, components are
processed at high temperatures using the
so-called reflow soldering process.A high
700 900 1,000 1,500
+50%
+80%
1,800 2,300
2,500
2,000
1,500
1,000
500
0
h
HT1 GF 50 HT1 GF 50
more hydrolysis-resistant
HT3 GF50 H
Time
Elongation at break [MPa]
Tensile stress at break [MPa]
Hydrolysis Resistance
Fig. 1. It has been
possible to increase
the half-value time
for the mechanical
properties of the ex-
tremely low-moisture
PPA Grivory HT3 by
up to 80% compared
to hydrolysis-resist-
ant Grivory HT1
© Kunststoffe
Hydrolysis-
resistance
Chemical
resistance
Impact
strength
Notched
impact strength
StiffnessElongation
Water
uptake
Strength
Grivory HT1
Grivory HT3
Higher/better
Characteristics
Fig. 2. Grivory HT3
distinguishes itself
as an optimum design
material above all
through its low mois-
ture uptake, excel-
lent hydrolysis resist-
ance and outstanding
toughness
© Kunststoffe
© Carl Hanser Verlag, Munich Kunststoffe international 8/2008](https://image.slidesharecdn.com/9f432eb4-187c-413c-9af6-2445f24cbe05-150705025543-lva1-app6891/85/The-Next-Generation-of-Polyphthalamide-2-320.jpg)
The Next Generation of Polyphthalamide
- 1. The Next Generation of Polyphthalamide High-performance Polyamides. For years and to an increasing ex- tent, plastics have been replacing diecast metal parts. Structural and functional parts for many applications can now be pro- duced from polyphthalamide (PPA). These can be found under the hood in automobiles, in hot water applications in the sanitary field as well as in industrial ap- plications, e.g. for coffee ma- chines. An advanced grade of this high-performance polyamide is characterized by its extremely low moisture uptake. A polyphthalamide with extremely low moisture uptake is particularly well-suited for production of connectors in the electronics sector 75 COMPOUNDS ■ V Kunststoffe international 8/2008 MICHAEL KAISSER T he polyphthalamide Grivory HT is characterized by high rigidity and strength at temperatures up to 150°C. It is very resistant to chemicals and exhibits minimal change in physical properties after moisture uptake. Grivory HT3 is an even more advanced PPA whose moisture uptake has been minimized.This is important in the elec- trical and electronic fields when com- ponents undergo lead-free reflow sol- dering and functional parts must have extremely good dimensional stability (Title photo). In addition, Grivory HT3 is an extremely hydrolysis-resistant and tough material.During its development, Ems-Grivory also displayed its concern for the environment. Grivory HT3 is produced largely from renewable re- sources. Wide Range of Applications As a materials group, polyphthala- mides have been known for a long time and have been successful replace- ments for metal in numerous applica- tions in almost all branches of industry. Typical representatives from Ems- Grivory include Grivory HT1 (PA6T/6I) and Grivory HT2 (PA6T/66). These are used when economical alternatives to diecast metals such as zinc,aluminum or brass are required. Technical injec- tion molded parts made from these PPA products distinguish themselves through dimensional stability – even at high working temperatures of up to150°C. PE104325 Ems-Chemie AG Business Unit Ems-Grivory CH-7013 Domat/Ems Switzerland Tel. +41/81/6 32-6922 www.emsgrivory.com Manufactureri Translated from Kunststoffe 8/2008, pp. 111–113
- 2. 76 COMPOUNDS■ Grivory HT3 is a completely new PPA polymer that is based on long-chain di- amines. It exhibits important character- istics which are further improved com- pared to those of Grivory HT1 and HT2. These give it access to fields of applica- tion from which polyphthalamides have so far been excluded. Reduced Moisture Uptake Until now, polyamides were limited by the fact that moisture uptake seriously af- fected material properties.While it is true that moisture uptake made them tougher, stiffness and strength were sig- nificantly reduced. By their nature, polyphthalamides also absorb moisture, but to a much lesser degree and much more slowly. In the case of Grivory HT3, it has been possible to markedly reduce moisture uptake to 50% of that of Grivory HT1. The consequence is that the new material exhibits exceptional di- mensional stability and very little ten- dency to creep.Its physical properties are essentially unaffected by moisture in the surroundings. The long-chain diamines in the poly- mer chain provide increased hydrolysis resistance.Thisisclearlydemonstratedby the extended half-value time after storage in a water/glycol mixture at 135°C. Elon- gation at break and tensile stress at break for Grivory HT3 drop to half their initial values only after 1,800 h (elongation at break) and 2,300 h (tensile stress at break). This corresponds to an increase inthehalf-valuetimesof 80and50%over those of the already hydrolysis-resistant Grivory HT1 GF50 grade (Fig. 1). With its outstanding elongation and toughness, Grivory HT3 contradicts the prevailing opinion that PPA may indeed be very stiff but is also rather brittle.Even when highly reinforced,Grivory HT3 is a tough material with high elongation at break. As are all polyphthalamides, it is extremely chemical-resistant and it has been possible to further improve the per- formance in hot oil (Fig. 2). At Home in All Market Segments Grivory HT is accepted in many applica- tions encountered in daily life and has been recognized as a metal replacement for years. It allows cost-effective produc- tion of lightweight parts that can with- standhighmechanical loads –amajorre- quirement for automotive components. Its property profile is also appreciated in this segment for other reasons. The very good hydrolysis resistance and dimen- sional stability benefits components that are in continuous contact with coolants. Theseincludewaterpumps,radiatorcaps and expansion tanks. In combination with exceptionally low permeation, the goodchemicalresistanceandhightough- ness predestine Grivory HT3 as a materi- al for highly stressed connectors in fluid- conducting systems (Fig. 3). The electronics industry relies in- creasingly on miniaturization. Compo- nents are becoming smaller and smaller and more complex.At the same time,re- quirements regarding performance un- der extreme temperatures and repro- ducibility are becoming more demand- ing. Flame retardance is another essen- tial requirement. Grivory HT3 employs a halogen and phosphorus-free flame re- tardant that satisfies the WEEE and RoHS requirements. It also offers major benefits during the production process itself. The halogen and phosphor-free PPA products on the market to date have been extremely corrosive when it comes to barrels, screws and non-return valves of injection molding machines. Accord- ingly, a great deal of attention was de- voted to this aspect during development. Grivory HT3 is significantly less corro- sive than previous halogen and phos- phorus-free flame-retardant polyph- thalamides on the market. This proper- ty in particular makes it a favorite inAsia for the manufacture of connectors. The first mobile phones with connectors made of Grivory HT3 are currently be- ing shipped. As in the automotive industry, low moisture uptake and high dimensional stability play an important role in the electronics sector. Here, components are processed at high temperatures using the so-called reflow soldering process.A high 700 900 1,000 1,500 +50% +80% 1,800 2,300 2,500 2,000 1,500 1,000 500 0 h HT1 GF 50 HT1 GF 50 more hydrolysis-resistant HT3 GF50 H Time Elongation at break [MPa] Tensile stress at break [MPa] Hydrolysis Resistance Fig. 1. It has been possible to increase the half-value time for the mechanical properties of the ex- tremely low-moisture PPA Grivory HT3 by up to 80% compared to hydrolysis-resist- ant Grivory HT1 © Kunststoffe Hydrolysis- resistance Chemical resistance Impact strength Notched impact strength StiffnessElongation Water uptake Strength Grivory HT1 Grivory HT3 Higher/better Characteristics Fig. 2. Grivory HT3 distinguishes itself as an optimum design material above all through its low mois- ture uptake, excel- lent hydrolysis resist- ance and outstanding toughness © Kunststoffe © Carl Hanser Verlag, Munich Kunststoffe international 8/2008
- 3. 77 moisture uptake would result in consid- erableblisteringduetooutgassingattem- peratures of up to 260°C. Use of reflow soldering is much simpler when Grivory HT3 is involved. It is even possible to at- tain the highest and very important clas- sification,JEDEC class 1,for applications in this sector (Fig. 4). Grivory HT is suitable for a wide range of applications in industry and the con- sumerarea.Thankstoitssignificantlyim- proved hydrolysis resistance, Grivory HT3 can be used wherever high temper- atures and direct contact with water oc- cur. For instance, it can replace diecast functional components in coffee ma- chines, because the material can with- stand high pressures and temperatures, and survive the specified number of brewing cycles. Thanks to it high-tem- perature capabilities and good resistance to water, this poses no problems for Grivory HT3. Product approvals for di- rect contact with foodstuffs (EU, FDA, NSF 51) and drinking water (KTW, W270, ACS, WRAS, NSF 61) are ab- solutely essential in this regard. Simple Processing The Grivory HT3 grade of PPA has a melting point of 295°C, which is below that of Grivory HT1 (325°C) and HT2 (310°C). This lower melting point widens the processing window, so that the injection molder can operate within a wide range of process temperatures. The recommended stock temperature ranges from 305 to 330°C, with lower temperatures used for unreinforced grades of Grivory HT3 and higher tem- peratures for reinforced grades. The mold temperature is another important process parameter. The correct mold temperature is a prerequisite for pro- duction of high-quality injection mold- ed parts with minimal warpage, low in- ternal stresses and tight dimensional tol- erance. The recommended mold tem- perature for Grivory HT3 lies between 115 and 140°C, so that it is possible to used pressurized water equipment for mold temperature control. Many Different Grades Grivory HT3 is available in heat-stabi- lized as well as unreinforced and rein- forced (30 to 50% glass fiber reinforce- ment)grades.Forapplicationsintheelec- trical and electronic sectors, glass fiber- reinforced,halogen andphosphorus-free flame-retardant products with greatly re- duced corrosiveness are available. The material is also approved for applications involving direct contact with foodstuffs and drinking water. Conserving Resources Grivory HT3 is based to a large extent on a raw material that is extracted from the castor bean plant (Rhizinus communis), a natural and renewable resource.As a re- sult, after use, only the amount of CO2 is released that the castor bean plant itself extracted from the atmosphere during its growth. Grivory HT3 thus represents the first commercially available polyphthal- amide that is based verifiably on a re- newable resource. ■ THE AUTHOR DIPL.-ING. (FH) MICHAEL KAISSER, born in 1970, works in the automotive applications development department at Ems-Grivory, Domat/Ems, Switzerland; michael.kaisser@emsgrivory.com Fig. 3. The outstand- ing toughness and good permeation characteristics pre- destine Grivory HT3 as a material for con- nectors in fuel lines for automobiles Fig. 4. After reflow soldering, Grivory HT3 exhibits no signs of blistering; compo- nents achieve the highest JEDEC classification (JEDEC class 1) COMPOUNDS ■ Kunststoffe international 8/2008 Technology Report Archive: Articles with high focus on practical ideas and with additional background information on trend-setting technologies available at www.kunststoffe-international.com/tr Kunststoffe-international.com