SOLID SILICONE COMPOSITIONS AND METHODS FOR THEIR PREPARATION AND USE

Abstract: Disclosed are solid silicone compositions comprising low molecular weight polyethylene solidifying agents and one or more non-volatile silicone fluids, along with a method for their preparation. The compositions are suitable for topical application to skin or hair, and are particularly useful in the preparation of novel skin treatment, hair treatment, lipstick and makeup products.

Description: SOLID SILICONE COMPOSITIONS AND METHODS FOR THEIR PREPARATION AND USE FIELD OF THE INVENTION The present invention relates to solid silicone compositions suitable for topical appUcation to human skin or hair. In particular, the invention relates to solid silicone compositions comprising a low molecular weight polyethylene sohdifying agent and one or more non-volatile silicone fluids. The invention additionally relates to methods for the preparation and use of such compositions. BACKGROUND OF THE INVENTION Silicones are rapidly becoming ubiquitous components of pharmaceutical and personal care products. Their remarkably high thermal and chemical stability, their unusual ability to resist adhering to other materials and their aesthetically unique and pleasing tactile characteristics have made sihcones invaluable raw materials in products designed for topical appUcation to the skin or hair, such as skin treatment preparations, hair conditioners, lipsticks and makeup products. Such products are often desirably formulated in the foπn of sticks or gels for the elegance and ease of appUcation these product forms offer to the consumer. The term "siUcones" actually encompasses a large and diverse group of polymeric fluids, oils, rubbers, resins and gums generaUy based on the structural unit -R 2 SiO-, with R being a monovalent orgamc radical. The type and size ofthe radicals) present (e.g., alkyl vs. aryl), the type and degree of polymerization (e.g., Unear vs. cycUc), and the presence or absence of crosslinking, aU affect the physical and chemical properties ofthe resultant silicone polymers. Silicone fluids may be broadly classified as being either volatile or non-volatile, depending on how large a vapor pressure they possess at ambient temperature and pressure. SiUcone fluids may also be characterized by their degree of viscosity, where viscosity is defined as resistance to flow and is commonly measured in centistokes. For a paπicular silicone polymer the viscosity generally increases, and the volatility generally decreases, as the molecular weight ofthe polymer increases. Commercially available volatile silicone fluids include hexamethyldisiloxane [(CH 3 ) 3 SiOSi(CH 3 ) 3 ]; methylated cycUc silicones (also referred to as cyclomethicones) which include octamethyl cyclotetrasiloxane, an eight-membered ring compound formed from four Si-(CH 3 ) -O groups, and decamethylcyclopentasiloxane, a ten-membered ring compound formed from five Si-(CH 3 ) 2 -O groups; and dimethicones having a viscosity of 10 centistokes or less. Dimethicones are Unear silicone polymers conforming to the structure: CH 3 CH 3 CH 3 I I I CH 3 -Si-O- [ Si-O-] „ -Si- CH 3 I I I CH 3 R CH 3 I wherein R is methyl. Volatile silicone fluids are generaUy compatible with many ofthe UpophiUc materials commonly employed in topical compositions. They are use in such compositions for their ability to act as co-soh ents, as weU as to provide a dry, non-greasy feel to the compositions during appUcation to the skin or hair. Commercially available non-volatile silicone fluids include dimethicones having a viscosity of greater than 10 centistokes, alkylated dimethicones such as cetyl dimethicone (L R = a mixture of CH 3 and CιβH 33 ), and trimethicones such as phenyl trimethicone (H): CH 3 R CH 3 I I I CH 3 -Si-O- [ Si-O-] n -Si- CH 3 I I I CH 3 O CH 3 I Si(CH 3 ) 3 H wherein R is phenyl. Non-volatile silicone fluids are used in topical compositions to provide a sUppery yet non-greasy feel to the compositions, and to provide an occlusive, water-resistant and emollient film to the skin surface upon topical appUcation. They are also used as conditioners in hair treatment products, and as emulsion stabilizers in products formulated as oil-in-water or water-in-oil emulsions. Non-volatile silicone fluids are markedly less compatible than their volatile counterparts with many ofthe lipophilic materials commonly used in topical compositions. Silicone gums are non-volatile silicone fluids possessing particularly high viscosities and molecular weights, and include dimethicones having viscosities of about 1,000,000 centistokes. Such gums are used in topical compositions for their unique tactile and film-forπijng properties, and are available commercially both in gum form and as free- flowing dispersions in silicone fluid carriers. It is known in the art that polyethylenes are useful gelling agents for volatile silicone fluids. Polyethylenes are polymers of ethylene monomers that conform generaUy to the formula (C 2 H ) n , wherein n is usuaUy large enough such that the resultant polymers have average molecular weights of from about 1500 to about 100,000. U.S. Patent No. 5,122,519 to Ritter discloses topical gel formulations contaimng a tetracycline antibiotic, a volatile silicone solvent, an emollient ester co- solvent and a polyethylene gelling agent. U.S. Patent No. 5,102,656 to Kasat discloses, inter alia, antiperspirant creams contaming a volatile silicone, a polyethylene gelling agent, and an antiperspirant active. Japanese PubUshed Unexamined AppUcation JP 61069711 A discloses, inter alia, soUd cosmetic compositions containing a volatile silicone oil, a polyethylene gelling agent and a powder substrate. The use of polyethylenes as soUdifying agents for non-volatile siUcone fluids has not been heretofore disclosed. In fact, most commercially available polyethylenes arc known to be only minimaUy soluble in, and hence incompatible with, many ofthe non¬ volatile silicones used in topical compositions. It has now been discovered that low molecular weight polyethylenes, i.e.. polyethylenes having an average molecular weight of less than about 1,000, are exceUent soUdifyi-αg agents for siUcone fluids. In particular, it has been surprisingly and unexpectedly discovered that such low molecular weight polyethylenes are exceUent soUdifying agents for non-volatile siUcone fluids. It has also been suφrisingly and unexpectedly discovered that compositions prepared from low molecular weight polyethylenes and non-volatile silicone fluids are stable, aesthetically elegant and useful in the preparation of novel skin treatment, hair treatment, Upstick and makeup products. It is therefore an object ofthe present invention to provide soUd siUcone compositions suitable for topical appUcation to human skin or hair which contain non¬ volatile siUcone fluids. It is also an object of this invention to provide soUd silicone compositions comprising a low molecular weight polyethylene soUdifying agent and one or more non-volatUe siUcone fluids. Further objects of this invention are to provide a method for the preparation of such soUd silicone compositions, and to provide skin treatment, hair treatment, Upstick and makeup compositions comprising the soUd silicone compositions of the invention. SUMMARY OF THE INVENTION In accordance with the present invention there are provided soUd silicone compositions suitable for topical appUcation to human skin or hair which comprise: (a) from about 3 to about 20 weight percent ofa polyethylene soUd-_fying agent having an average molecular weight of less than about 1,000; and (b) from about 20 to about 97 weight percent ofa non- volatile silicone fluid. The present invention additionaUy relates to a method for preparing such compositions, the method comprising the steps of: (a) mixing a non-volatile siUcone fluid with a polyethylene soUdifying agent having an average molecular weight of less than about 1,000 at a temperature and for a time sufficient to dissolve the polyethylene soUdifying agent in the siUcone fluid, the amount of materials being adjusted such that the resultant mixture contains from about 3 to about 20 weight percent ofthe polyethylene soUdifying agent and from about 20 to about 97 weight percent ofthe siUcone fluid; and (b) aUowing the mixture to cool to about ambient temperature. It is to be understood that the terms "mixture" and ''mixing" in this appUcation are used in the broad sense ofthe words with the term ''mixing" including, but not being limited to, stirring, blending, dispersing, milling, homogenizing and the Uke. The soUd silicone compositions ofthe present invention are stable against both physical and chemical degradation during extended storage, over a wide temperature range. They are aestheticaUy elegant and non-irritating upon appUcation to the skin or hair, and provide an occlusive, water-resistant and emollient film upon topical appUcation. The compositions ofthe invention are particularly useful in the preparation of skin treatment, hair conditioner, Upstick and makeup products. DETAILED DESCRIPTION OF THE INVENTION As mentioned hereinabove, the present invention provides soUd silicone compositions suitable for topical appUcation to human skin or hair which comprise: (a) from about 3 to about 20 weight percent ofa polyethylene soUdifying agent having an average molecular weight of less than about 1,000; and (b) from about 20 to about 97 weight percent ofa non-volatile siUcone fluid. The compositions comprise from about 3 to about 20 weight percent, preferably from about 3 to about 12 percent and more preferably about 10 weight percent ofthe low molecular weight polyethylene soUdifying agent. The polyethylene soUdifymg agent preferably has an average molecular weight of from about 200 to about 800, more preferably from about 400 to about 600, most preferably about 500. In an especiaUy preferred embodiment ofthe mvention the polyethylene soUdifying agent is a straight- chain homopolymer of polyethylene having an average molecular weight of about 500, available commerciaUy from PetroUte Corporation, Polymers Division (Tulsa, OK) under the tradename Siltex PL. In addition to the polyethylene soUdifying agent, the compositions comprise from about 20 to about 97 weight percent ofa non-volatile siUcone fluid. In a first prefeπed embodiment ofthe invention the non- volatile silicone fluid comprises a dimethicone having a viscosity of from about 10 to about 50 centistokes, especiaUy a dimethicone having a viscosity of about 20 centistokes. In a second preferred embodiment ofthe invention the non- volatile silicone fluid comprises a phenyl trimethicone having a viscosity of from about 10 to about 1150 centistokes, especiaUy a phenyl trimethicone having a viscosity of from about 12 to about 56 centistokes. In a third prefeπed embodiment ofthe invention the non-volatile siUcone fluid comprises a mixture ofa dimethicone and a phenyl trimethicone, especiaUy a mixture ofa dimethicone having a viscosity of from about 10 to about 1000 centistokes and a phenyl trimethicone having a viscosity of from about 12 to about 56 centistokes. In a preferred embodiment ofthe present invention the siUcone fluid comprises one or more siUcone gums. One such siUcone gum is available commercially under the tradename SE-30 Silicone Gum from GE Silicones (Waterford, NY). The siUcone gum may be introduced into the compositions either in gum foπn or as a dispersion in other siUcone fluids. Such dispersions are available commerciaUy from GE Silicones, Dow Corning Corporation (Mt. Olive, NJ), and Grant Industries, Inc. (Elmwood Park, NJ). The compositions of this invention additionaUy may comprise one or more pharmaceuticaUy or cosmeticaUy acceptable materials which are soluble in, or otherwise compatible with, the siUcone fluid(s). 'ThaπnaceuticaUy or cosmeticaUy acceptable" as used herein refers to materials that are not known to be harmful to humans. These materials can be found for example in the CTFA International Dictionary of Cosmetic Ingredients as weU as the U.S. Pharmacopeia or equivalent sources. Suitable cosmeticaUy or pharmaceuticaUy acceptable material for purposes ofthe present invention include, but are not limited to: oils; colorants; fragrances; sunscreens; stabilizers; preservatives; antioxidants; pharmacologicaUy active materials; and mixtures thereof The specific type and amount of pharmaceuticaUy or cosmeticaUy acceptable material used wiU vary with the desired physical, aesthetic and pharmacological properties ofthe final composition, and is readily determined by the skilled artisan. In a preferred embodiment ofthe invention the compositions comprise one or more oils. The oils can function in the compositions as skin and hair conditioning agents, for example as emollients and occlusive agents. Emollients help maintain the softness, smoothness and pliability of skin and hair; occlusive agents minimize the evaporative loss of water from skin and hair surfaces. Suitable oils include, but are not limited to: natural oils, especiaUy squalane and jojoba oil; hydrocarbons; fatty alcohols; fatty acids; esters; sterols; and mixtures thereof. In a preferred embodiment the oil is an ester which is derived from a straight or branched chain fatty alcohol and or a straight or branched chain fatty acid. Examples of emollient esters include: isopropyl myristate; isopropyl palmitate; isononyl isononanoate; isooctyl isononanoate; isononyl isomyristate; isodecyl isononanoate; and mixtures thereof. In another preferred embodiment ofthe invention the compositions comprise one or more colorants. Suitable colorants include, but are not limited to: dyes; stains; metal oxides, especiaUy iron oxide and titanium dioxide; metal powders; and organic pigments. In yet another preferred embodiment ofthe invention the compositions comprise one or more sunscreens. The term "sunscreen" as used herein refers to any material which is capable of protecting human skin from ultraviolet radiation having a wavelength of from about 280 to about 400 nm, by effectively absorbing such radiation, and/or reflecting or scattering such radiation away from the surface ofthe skin. Suitable sunscreens include, but are not limited to: inorganic sunscreens, such as titanium dioxide and zinc oxide; orgamc sunscreens, such as 2-ethylhexyl p- methoxycin-Qamate; and mixtures thereof In yet another preferred embodiment ofthe invention the compositions mclude one or more pharmacologicaUy active materials. EspeciaUy prefeπed as pharmacologically active material are dermatologicaUy active materials including, but not limited to: vitamins, such as vitamin E and vitamin E acetate; antiperspirant agents; antiacne agents; antidandruff agents; antifungal agents; antiinflammatory agents; and mixtures thereof. As mentioned hereinabove, the present invention additionaUy relates to a method for preparing soUd silicone compositions suitable for topical appUcation to human skin or hair, the method comprising the steps of: (a) mixing a non-volatile silicone fluid with a polyethylene soUdifying agent having an average molecular weight of less than about 1,000 at a temperature and for a time sufficient to dissolve the polyethylene soUdifying agent in the siUcone fluid, the amount of materials being adjusted such that the resultant mixture contains from about 3 to about 20 weight percent ofthe polyethylene soUdifying agent and from about 20 to about 97 weight percent ofthe silicone fluid; (b) aUowing the mixture to cool to about ambient temperature. The optimal temperature and time sufficient to dissolve the polyethylene solidifying agent in the silicone fluid will vary with the exact materials used, and is readily determined by one skilled in the art. GeneraUy speaking, a temperature of from about 90 to about 110 °C, and usuaUy from about 90 to 95 °C, for a period of about 15 minutes is sufficient to accompUsh this dissolution. The compositions ofthe present invention may be formulated for a wide range of topical skin and hair appUcations. For example, the compositions may be formulated as Up area treatment preparations, eye area treatment preparations, sunscreen preparations, fragrance preparations, Upsticks, blushes, foundations, eyeshadows, hair conditioners and the Uke. The foUowing non-limiting examples illustrate various embodiments ofthe present invention: EXAMPLES 1-3: SOLID SILICONE COMPOSITIONS INGREDIENT WEIGHT PERCENT EXAMPLE 1 EXAMPLE 2 EXAMPLE 3 Low Molecular Weight Polyethylene ' 10 10 10 Dimethicone, 10 Centistokes 2 90 Phenyl Trimethicone, 15-30 Centistokes 3 — 90 Phenyl Trimethicone, 850-1150 Centistokes 4 --- -- 90 1 SUtex PL (Petrohte Corp., Polymers Division, Tulsa OK) 2 Dow Corning 200 Fluid, 20 Centistokes (Dow Corning Corp., Mt. Olive, NJ) 3 SiUcone 556 Fluid (Dow Corning Corp., Mt. Olive, NJ) 4 Abil AV 1000 (Goldschmidt Chemical Corp., HopeweU, VA) PROCEDURE For each of Examples 1 - 3, the low molecular weight polyethylene and the non¬ volatile silicone fluid were combined and heated with mixing to 90-95 °C for about 15 minutes to effect complete dissolution ofthe polyethylene. The mixture was then aUowed to cool to room temperature to afford a stable, cosmeticaUy elegant soUd composition suitable for topical appUcation to human skin or hair. EXAMPLE 4: LIPSTICK COMPOSITION INGREDIENT WEIGHT PERCENT Dimethicone, 200 Centistokes 1 21 Phenyl Trimethicone, 35-56 Centistokes 2 50 Dimethicone Gum 3 5 Tocopheryl Acetate 4 2 Jojoba Oil 5 2 D&C Red No. 6 Barium Lake 6 5 D&C Red No.7 Calcium Lake 7 5 Low Molecular Weight Polyethylene 8 10 ' Dow Corning 200 Fluid, 20 Centistokes (Dow Coming Corp., Mt. Olive, NJ) Dow Corning 2-2757 Fluid (Dow Corning Corp., Mt. Olive, NJ) 3 SE-30 Si cone Gum (GE Silicones (Waterford, NY) 4 DL-α-Tocopheryl Acetate USP (Hof-αnann - La Roche Inc., Nutley, NJ) 5 Jojoba Oil Refined Grade (International Flora Technologies, Ltd., Gilbert, AZ) 6 7 Sun Chemical Corp. (Staten Island, NY) 8 Siltex PL (PetroUte Corp., Polymers Division, Tulsa OK) PROCEDURE The above ingredients were combined and heated with mixing to 90-95 °C for about 15 minutes to effect complete dissolution ofthe polyethylene. The mixture was then aUowed to cool to room temperature to afford a stable, cosmeticaUy elegant Upstick composition. While the present invention has been set forth in terms of specific embodiments thereof, it will be understood that numerous variations are now enabled to those skilled in the art. Accordingly, the invention is to be broadly construed and Umited only by the scope ofthe appended claims.

Claims: What is claimed is: 1. A soUd silicone composition suitable for topical appUcation to human skin or hair which comprises: (a) from about 3 to about 20 weight percent ofa polyethylene soUάΗying agent having an average molecular weight of less than about 1,000; and (b) from about 20 to about 97 weight percent ofa non- volatile silicone fluid. 2. The composition of claim 1 wherein the polyethylene has an average molecular weight of from about 200 to about 800. 3. The composition of claim 1 wherein the polyethylene soUdifying agent has an average molecular weight of about 400 to about 600. 4. The composition of claim 1 wherein the polyethylene soUdifying agent has an average molecular weight of about 500. 5. The composition of claim 4 wherein the polyethylene soUdifying agent is a straight chain homopolymer of polyethylene. 6. The composition of claim 1 comprising from about 3 to about 12 weight percent ofthe polyethylene soUdifying agent. 7. The composition of claim 6 comprising about 10 weight percent ofthe polyethylene soUάΗying agent. 8. The composition of claim 6 wherein the non- volatile silicone fluid is a dimethicone having a viscosity of from about 10 to about 50 centistokes. 9. The composition of claim 8 wherein the dimethicone has a viscosity of about 20 centistokes. 10. The composition of claim 1 wherein the non- volatile silicone fluid is a phenyl trimethicone having a viscosity of from about 10 to about 1150 centistokes. 11. The composition of claim 10 wherem the phenyl trimethicone has a viscosity of from about 12 to about 56 centistokes. 12. The composition of claim 1 wherein the non-volatUe silicone fluid comprises a mixture of dimethicone and phenyl trimethicone. 13. The composition of claim 12 wherein the dimethicone has a viscosity of from about 10 to about 1,000 centistokes and the phenyl trimethicone has a viscosity of from about 12 to about 56 centistokes. 14. The composition of claim 1 wherein the siUcone fluid comprises a silicone gum. 15. The composition of claim 1 additionally comprising an oil. 16. The composition of claim 15 wherein the oU is selected from the group consisting of jojoba oil and squalane. 17. The composition of claim 15 wherein the oU is selected from the group consisting of esters derived from fatty alcohols and esters derived from fatty acids.. 18. The composition of claim 1 additionaUy comprising a colorant. 19. The composition of claim 18 wherein the colorant is selected from the group consisting of metal oxides and organic pigments. 20. The composition of claim 19 wherein the metal oxide is selected from the group consisting of titanium dioxide and iron oxide. 21. The composition of claim 1 additionaUy comprising a sunscreen. 22. The composition of claim 1 additionaUy comprising a pharmacologicaUy active material. 23. The composition of claim 22 wherem the pharmacologicaUy active material is a dermatologicaUy active material. 24. A soUd siUcone composition suitable for topical appUcation to human skin or hair which comprises: (a) from about 3 to about 20 weight percent ofa polyethylene soUdifying agent having an average molecular weight of less than about 1,000; (b) from about 20 to about 97 weight percent ofa non- volatile silicone fluid comprising from about 0.5 to about 25 weight percent ofa siUcone gum; (d) from about 0.5 to about 75 weight percent of an oil; and (e) from about 0.1 to about 30 weight percent ofa colorant. 25. The composition of claim 24 wherem the polyethylene soUdifying agent has an average molecular weight of about 500. 26. The composition of claim 25 wherein the polyethylene soUdifying agent is a straight chain homopolymer of polyethylene. 27. A method for preparing a soUd siUcone composition suitable for topical appUcation to skin or hair, the method comprising the steps of: (a) mixing a non-volatile siUcone fluid with a polyethylene soUdifying agent having an average molecular weight of less than about 1,000 at a temperature and for a time sufficient to dissolve the polyethylene soUdifying agent in the silicone fluid, the amount of materials being adjusted such that the resultant mixture contains from about 3 to about 20 weight percent ofthe polyethylene soUdifying agent and from about 20 to about 97 weight percent ofthe siUcone fluid; (b) aUowing the mixture to cool to about ambient temperature. 28. A soUd silicone conmosition prepared according to the method of claim 27. 29. A skin treatment composition comprising the soUd silicone composition of claims lor 28. 30. A Upstick composition comprising the soUd silicone composition of claims 1 or 28. 31. A makeup composition comprising the soUd silicone composition of claims 1 or 28.

Inventors: STEPNIEWSKI GEORGE, STEPNIEWSKI, GEORGE
Applicants: ESTEE LAUDER INC, ESTEE LAUDER, INC.
Application year: 1996
Main classification: A61K7
IPC codes: A61K8, A61Q1, A61Q5, A61Q17, A61Q19, C08L83