Use of hydrophilic-rich alkylmethylsiloxane-dimethylsiloxane-polyoxyalkylene copolymers as emulsifiers for the preparation of cosmetic o/w emulsions of improved aesthetic properties and mildness

Abstract

This invention relates to the use of hydrophilic-rich, rake-type alkylmethylsiloxane-dimethylsiloxane-polyoxyalkylene copolymers. A hydrophilic-rich alkylmethylsiloxane-dimethylsiloxane-polyoxyalkylene copolymer is hereby defined as an alkylmethylsiloxane-dimethylsiloxane-polyoxyalkylene copolymer possessing sufficient hydrophilic content such that it can be readily taken up by water at a concentration of at least 15% by mass copolymer with simple stirring at room temperature to yield a stable dispersion of micron and sub-micron sized particles. This definition supercedes the typical values of the formula variables x, y, z, q, and p specified above to include all values that result in the copolymer being hydrophilic-rich. This definition also supercedes the typical identity of R=dodecyl shown above to include R being any alkyl or branched-alkyl chain of any length such that the resulting copolymer is hydrophilic-rich. This definition also supercedes the typical identity of the polyoxyalkylene shown above to include polyoxyalkylenes possessing propylene oxide repeat units as well as ethylene oxide repeat units such that the resulting copolymer is hydrophilic-rich. This definition also supercedes the typical identity of R′=H, Me shown above to include any alkyl, aryl, or acyl radical such that the resulting copolymer is hydrophilic-rich. This invention also relates to the use of these copolymers as emulsifiers for the preparation of cosmetic O/W formulations (defined as stable O/W emulsions of water, one or more oils that may include silicone oils, and various other ingredients that may include preservatives, fragrances, coloring agents, etc.) that yield improved aesthetic properties (including appearance and texture of the cosmetic emulsion, initial feel on the skin, and final feel on the skin after rub-out) and improved mildness relative to comparable cosmetic emulsions that employ other silicone-copolymer emulsifiers as well as other non-silicone emulsifiers.

What is claimed is: 
     
         1 . The use for the formation of stable o/w emulsions of hydrophilic-rich organo-functional silicone copolyols, that are intermediate between the typically hydrophilic silicone copolyols and typically hydrophobic organo-functional silicone copolyols. 
     
     
         2 . The alkyl dimethicone copolyol emulsifiers of this invention have additional benefits of providing lift from the surface, creating an overall skin feel that is soft and extremely smooth. This softening effect is important beyond aesthetics in that it reduces the overall roughness of the surface of the skin, allowing light to reflect more evenly. The skin appears more uniform in color and texture, a benefit strongly desired in anti-aging skin care products. This benefit is not observed using either the aforementioned alkyl dimethicone copolyol w/o emulsifiers of the prior art (such as Goldschmidt ABIL EM90) or o/w emulsifiers of the dimethicone copolyol variety (such as Dow Corning DC 193) or o/w emulsifiers of the non-silicone containing variety (such as Glyceryl Stearate and PEG 100 Stearate). Additional benefits provided by the emulsifiers of this invention over the aforementioned emulsifiers are a reduction of greasy feeling for emulsions that have high (15% or higher) oil and/or petrolatum content, a brilliant white appearance and less dense, soufflé-like texture for said high oil and or petrolatum emulsions, a decreased rub in time, a final rub out that is less greasy, and a markedly decreased irritancy.