Read Part 1 here.
Silicone elastomers are cross-linked gels dispersed in silicone or hydrocarbon carriers. Since first introduced to the personal-care industry by Shin-Etsu in 1988, they have had a major impact on color cosmetic, antiperspirant and skin-care formulations due to their outstanding properties. Typical uses include thickening, absorbing oil/sebum, mattifying, feel modification and to produce water in oil emulsions.
They are usually prepared by reacting a methyl hydrogen polysiloxane with a cross-linking agent (usually a vinyl-containing compound) in the presence of a silicone solvent and a platinum catalyst. The mixture is then diluted using a carrier solvent with high-shear processing.
Using alkyl hydrogen polysiloxanes, elastomers with better organic compatibility can be achieved. Emulsifying elastomer gels contain alkyl-functionalized (C12) silicone cross-linked with polyether and swollen in various organic oils. These can be used to produce emulsifier-free, quick-breaking, sterically stabilized water-in-oil emulsions that contain over 90 percent water.
Silicone resins are hydrid molecules comprised of inorganic silica and organopolysiloxanes that have a three-dimensional network made up of principally tri- or tetrafunctional units. Silicone resins are typically produced by reacting chlorosilanes in the presence of catalysts and with chemicals, such as an alkyl or phenyl chloride, in a fluidized bed reactor. The insoluble powders are referred to as polymethylsilsesquioxane and are used for soft-focus or wrinkle-blurring effects and as feel-modifiers to give a smooth, soft, non-tacky skin feel.
Soluble resins are called trimethylsiloxysilicate (MQ), polypropylsilsesquioxane, polyphenylsilsesquioxane and alkyldimethylsilyl polypropylsilsesquioxanes. They are used as film formers to improve the wear/transfer and wash resistance of cosmetics. MQ resins are normally too brittle to be used by themselves and are usually combined with other resins or silicone fluids for optimal film formation.
Silicone copolyols are surface-active ingredients that contain both a water-insoluble silicone backbone and water-soluble polyether groups. The ratio of the silicone to polyether—and the molecular weight and composition of the components—determine the solubility and specific properties of a product. The polyether groups can either be terminal or pendant on the silicone backbone. Silicone copolyols are made by hydrosilylation of apolyoxyalkylene monoallyl ether and an SiH fluid. They are used as dispersing agents, wetting agents, to reduce formulation tack, condition hair and as emulsifiers for both water-in-oil and oil-in-water emulsions.
Recommended elastomers (available as gels and powders):
- Dow Corning 9045 Silicone Elastomer Blend (cyclopentasiloxane, dimethicone crosspolymer) by Dow Corning
- USG-105 (dimethicone/vinyl dimethicone crosspolymer, methyl trimethicone) by Shin-Etsu
- Dow Corning 9701 Cosmetic Powder (dimethicone/vinyl dimethicone crosspolymer, silica) by Dow Corning)
- Silsoft* Silicone Gel (cyclopentasiloxane, cetearyl dimethicone/vinyl dimethicone crosspolymer) by Momentive Performance Materials.
- KSG-330 (PEG-15/lauryl dimethicone crosspolymer, triethylhexyanoin) by Shin-Etsu
- KSG-330 can produce sterically stabilized water-in-oil, emulsifier-free formulations containing mostly non-silicone emollients.
- KSG-210 (dimethicone, dimethicone/PEG-10/15 crosspolymer) by Shin-Etsu)
- KSG-210 can produce sterically stabilized water-in-oil, emulsifier-free formulations containing only silicone emollients.
Recommended silicone resins:
- Tospearls (polymethylsilsesquioxane) by Momentive Performance Materials
- Tospearls is a series of elastomer powders with different particle sizes.
- Dow Corning SW-8005 C30 Resin Wax (C30-45 alkyldimethylsilyl polypropylsilsesquioxane) by Dow Corning
- SW-8005 C30 is a soluble, film forming wax resin with a melting point of 66°C that has good compatibility in non-silicones.
- SilShine 151 Gloss Additive (polyphenylsilsesquioxane) by Momentive Performance Materials
- SilShine 151 is a phenyl resin that is a good film former and increases skin and hair shine better than phenyl trimethicone.
- Dow Corning MQ-1640 Flake Resin (trimethylsiloxysilicate, polypropylsilsesquioxane)by Dow Corning
- he resin combination provides both excellent transfer and wash-resistance combined with a flexible film and comfort of wear in skin and cosmetics applications.
Recommended silicone copolyols:
- Abil EM 90 and Abil EM 180 (cetyl PEG/PPG-10/1 dimethicone) by Evonik Industries
- EM 90 is probably the most popular silicone-based water-in-oil emulsifier on the market. It can be used with both silicone and non-silicone oil phases.
- EM 180 is a higher-MW upgrade version to EM 90 that can handle higher oil-phase volumes, alcohol up to 20 percent and 80 to 90 percent water.
- Dow Corning ES-5600 Silicone Glycerol Emulsifier (cetyl diglyceryl tris(trimethylsiloxy) silyethyl dimethicone) by Dow Corning
- ES-5600 claims to be useful in formulating low-viscosity water-in-oil emulsions and can be used with both silicone and non-silicone oil phases.
- KF-6038 (lauryl PEG-9 polydimethylsiloxyethyl dimethicone) by ShinEtsu
- SilForm EOF (polysilicone-25) by Momentive Performance Materials
- SilForm EOF is a water-in-oil emulsifier that contains no ethylene or propylene oxides. It claims to form higher-viscosity emulsions than competitive silicones.
- Dow Corning BY 25-339 Cosmetic Fluid (PEG/PPG-30/10 dimethicone, dipropylene glycol) by Dow Corning
- BY 25-339 is an oil-in-water or silicone-in-water emulsifier.
- KF-6004 Multi-Functional Care Additive (PEG-32 methyl ether dimethicone) by Shin-Etsu
- KF-6004 is a water-soluble silicone copolyol wax that can reduce tack, provide a silk-soft skin feel and condition hair.
- KF-6043 (PEG 10-dimethicone) by Shin-Etsu
- KF-6043 is an oil-in-water or silicone-in-water emulsifier and pigment-dispersing agent.
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