Rheological additives
- 1. BY SAYEDA SALMA 1ST M PHARM RHEOLOGICAL ADDITIVES 1
- 2. • Introduction • Cosmetics and Rheology • Classification of rheological additives • Applications • References INDEX 2
- 3. INTRODUCTION • Today’s successful cosmetics products need the right rheological properties and the correct choice of rheological additive enhances the product in production, storage stability and application. • rheological additives for aqueous and non-aqueous formulations are valuable and proven tools for you to use, a. Personal care b. skin care c. sun care d. decorative cosmetics • all can benefit from rheological additives. 3
- 4. • Rheology is the science of flow. • Every time a lotion is poured, a cream squeezed from a tube or a lipstick applied, rheology is involved. • Even when products are at rest, it plays an important part in controlling stability and suspension. • understanding a formulation’s rheological needs enables you to create the best possible products. • The rheology of a system is described in terms of its viscosity. Viscosity is the resistance to flow and defined as: VISCOSITY= shear stress/shear rate COSMETICS AND RHEOLOGY 4
- 5. • Shear stress is the force per unit area applied and shear rate is the resulting velocity gradient. • Cosmetics experience shear rates varying from 0.001 s-1, from gravitational forces to over 20,000 s-1, when a cream is spread or an aerosol antiperspirant sprayed. • The way the viscosity changes at varying shear rates greatly influences the overall product stability and performance. • A material which maintains a constant viscosity, regardless of shear rate, has Newtonian flow. • Dilatant flow is a form where viscosity increases with shear. • pseudoplastic flow, also known as shear thinning behavior, and typical of many commercial systems, is when viscosity decreases with increasing shear rate. • Viscosity can be temperature dependent, Correct choice of rheological additive allows you to create the ideal flow characteristics and also achieve thermostable rheology. 5
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- 7. • Aqueous-Phase Additives * Rheoluxe Associate Thickeners * hectorite * Bentone hydrophilic Clays • Non-Aqueous-Phase Additives * Bentone organophilic Clays * Bentone GEL * Thixcin R Rheological Additive CLASSIFICATION 7
- 8. 1) Rheoluxe Associative Thickeners • The rheoluxe family of rheology modifiers are non-ionic polymeric thickeners designed specifically for the personal care market. • Rheoluxe consists of urethane based and Polyether Polyol based associative thickeners with superior performance in difficult systems such as those containing high salt levels or with extremes in pH. • Due to its structure, Rheoluxe is soluble in water, but associates with lipophilic materials to build viscosity. AQUEOUS PHASE ADDITIVES 8
- 9. INCI NAME TYPICAL USE LEVEL CHEMISTRY RHEOLUXE 812 Bis-lauryl Cocaminopropylamine/hDI/PeG-100 Copolymer (and) Butylene Glycol 1.0-3.0% POLYURETHANE RHEOLUXE 880 Bis-C16-20 Isoalkoxy TMhDI/PeG-90 Copolymer 1.0-3.0% POLYURETHANE RHEOLUXE 8015 PeG/PPG-450/50 Trimethylolpropane Dodecyl ether 0.5-5.0% POLYETHER POLYOL EXAMPLES 9
- 10. 2) HECTORITE hectorite is a unique swelling clay offering several advantages. hectorite’s special properties are: lower iron content lighter colour higher swelling capacity greater gel strength platelet shape and large surface area 10
- 11. • hectorite is able to form strong, stable viscous gels. • hectorite is a very effective thickener of water. • Because of this and its other exceptional properties, it forms the basis as rheological additives in cosmetics. 11
- 12. • BENTONE MA, EW, and LT rheological additives provide thixotropy to the aqueous phase. • BENTONE MA and EW additives form gels by producing an open, 3-dimensional network of the individual clay platelets. • The two products are stable across the range pH 6-11 and offer good tolerance to electrolytes. • BENTONE LT forms a similar network, but it is strengthened by the presence of a special cellulose, greatly enhancing stability and thickening characteristics. • BENTONE LT is stable across a broader range, pH 3-11, and is also the least electrolyte- sensitive product. • BENTONE MA and EW are in compliance with ECOCERT , The ecological and organic cosmetics standards. BENTONE HYDROPHILLIC CLAYS 12
- 13. • Surfactants can influence the rheological behaviour of hydrophilic clays. • Non-ionic surfactants, if they are highly ethoxylated, can adsorb onto the clay surface , This rarely causes problems either in flow control or activity of the formulation. • Anionic surfactants can act as dispersing agents and weaken the gel structure , Alternatives that eliminate or minimise any problems can normally be found. • however, cationic surfactants interact strongly and should be avoided. • The benefits gained are: • thermostable viscosity control • thixotropic flow • emulsion stabilisation • silky skin feel 13
- 14. 1) BENTONE organophilic Clays • hectorite is now reacted with special vegetable quaternary ammonium salts to produce organoclays able to thicken and gel organic liquids. • The correct choice of bentone additive is determined largely by the polarity of the system to be thickened. NON – AQUEOUS PHASE ADDITIVES ADDITIVE APPLICATION BENTONE® 27 V * Intermediate to high-polarity organic systems such as esters and triglycerides - for nail lacquers, skin care, antiperspirants and lip products BENTONE® 38 V * Intermediate to low-polarity organic systems such as volatile silicones and mineral oil - for antiperspirants, creams, lotions, eye products and suntan products 14
- 15. • BENTONE additives need to be efficiently dispersed using high-shear equipment and then to be activated with the optimum level of a chemical activator, such as propylene carbonate. • BENTONE organoclays form thixotropic gels by developing hydrogen bond bridges between the edges of adjacent platelets. 15
- 16. • BENTONE GEL additives are optimally dispersed and activated pre- dispersions . • Benefits include: • optimally dispersed • high-shear dispersion not necessary • no polar activation required • easy to handle and use • can be added at any appropriate and convenient stage in manufacture • A wide range of gels made from various cosmetics oils, esters and solvents are available. BENTONE GEL 16
- 17. • The use of a BENTONE GEL enables you, the formulator, to achieve the maximum efficiency from the organoclay without the need for careful shearing and activation. • On the production scale, time is saved and the highest degree of reproducibility attained, leading to potential cost savings. 17
- 18. • For the highest degree of thixotropy in aliphatic liquids, Thixcin R additive is the product to use. • In addition to its effective rheological properties, it gives water repellency, stabilizes emulsions and acts as a stiffening agent in lipsticks and ointments. • It can also be used as a dry binder in pressed powder systems (Where high- temperature resistance is needed, BENTONE or BENTONE GEL additives are recommended). • Thixcin R is a castor oil derivative , It requires temperature-controlled activation within the range 55-60°C (130-140°F) and high-shear mixing to develop its full structure. • Thixcin R is in compliance with Ecocert, The ecological and organic cosmetics standards. THIXCIN R Rheological Additive 18
- 19. • Stick products (lipstick and antiperspirant) • maintain homogeneity in molten and setting stages • increase high-temperature integrity • eliminate oil migration • reduce “creasing” around lips and eyes • Mascara • improve film-build • increase water-resistance • eliminate oil migration APPLICATIONS 19
- 20. • Emulsions • elevate drop-point temperature of water-in-oil creams • eliminate syneresis • improve emulsion stability • enable cold-process emulsification • create novel viscosity effects • UV Sunscreen • eliminate ultrafine titanium di oxide skin-whitening problems • enhance sun protection factor (SPF) • optimise use of sunscreen actives • reduce separation and settlement 20
- 21. • Antiperspirant Aerosols • uniform distribution of active ingredients • soft and dry skin feel • significant less whitening • reduced separation and settlement 21
- 22. TRADE NAME INCI NAME BENTONE® EW Hectorite BENTONE® EW CE Hectorite BENTONE® LT Hectorite, Hydroxyethylcellulose RHEOLOGICAL MODIFIERS FOR AQUEOUS-PHASE 22
- 23. TRADE NAME INCI NAME BENTONE® 27 Steraralkonium Hectorite BENTONE® 27 V CG Steraralkonium Hectorite THIXCIN® R Trihydroxystearin RHEOLOGICAL MODIFIERS FOR NONAQUEOUS-PHASE 23
- 24. 24 • Rheology cosmetic brochure dec-2013 • BYK_BR_CO rheological additives_WEB_1 • Internet source REFERENCES
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