Silicone elastomer and skin care composition thereof

Abstract

Disclosed is a silicone elastomer obtainable by a hydrosilylation reaction of an organopolysiloxane having at least two Si-H bonds and rubber seed oil. Also disclosed are a blend comprising the silicone elastomer and a solvent, a method for preparing the blend, and a skin care composition comprising the blend.

Description

[0001] P0000155W01 CPL

[0002] 1

[0003] SILICONE ELASTOMER AND SKIN CARE COMPOSITION THEREOF

[0004] Field of the Invention

[0005] The present invention relates to a silicone elastomer. More particularly, the present invention relates to a silicone elastomer obtainable by a hydrosilylation reaction of an organopolysiloxane having at least two Si-H bonds and rubber seed oil. The invention also relates to a blend comprising the silicone elastomer and a solvent, a method for preparing the blend, and a skin care composition comprising the blend.

[0006] Background of the Invention

[0007] Silicone elastomers have been used extensively in skin care compositions to improve the sensorial properties of such compositions. Generally, the silicone elastomers are dosed in the form of a blend of the elastomer with a suitable solvent, which is a dispersion of the silicone elastomer in the solvent.

[0008] To improve compatibilities of silicone elastomers with various skin care ingredients, different approaches were developed such as optimizing solvent / elastomer blends, adding or changing the solvents, and / or adding modified polydimethicone polymer into the silicone elastomers. However, these silicone elastomers still have poor compatibility with various skin care ingredients such as hydrocarbon oils. The structure of the blend of these silicone elastomers and solvent may collapse which render it ineffective in providing desired sensorial properties.

[0009] There is a need to further improve the compatibility of silicone elastomers used in skin care compositions. The inventors of the present invention have discovered that silicone elastomer obtainable by reacting an organopolysiloxane having at least two Si-H bonds and rubber seed oil (RSO) has improved compatibility when used in skin care compositions.

[0010] Summary of the Invention

[0011] In a first aspect, the invention relates to a silicone elastomer obtainable by a hydrosilylation reaction of: a) an organopolysiloxane having at least two Si-H bonds; and b) rubber seed oil; in the presence of a hydrosilylation catalyst. P0000155W01 CPL

[0012] 2

[0013] In a second aspect, the invention relates to a blend comprising the silicone elastomer of the first aspect and a solvent.

[0014] In a third aspect, the invention relates to a method for preparing the blend of the second aspect.

[0015] In a fourth aspect, the invention relates to a skin care composition comprising the blend of the second aspect.

[0016] All other aspects of the present invention will more readily become apparent upon considering the detailed description and examples which follow.

[0017] Detailed Description of the Invention

[0018] Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and / or use may optionally be understood as modified by the word “about”.

[0019] All amounts are by weight of the final composition, unless otherwise specified. It should be noted that in specifying any ranges of values, any particular upper value can be associated with any particular lower value.

[0020] For the avoidance of doubt, the word “comprising” is intended to mean “including” but not necessarily “consisting of’ or “composed of”. In other words, the listed steps or options need not be exhaustive.

[0021] The disclosure of the invention as found herein is to be considered to cover all embodiments as found in the claims as being multiply dependent upon each other irrespective of the fact that claims may be found without multiple dependency or redundancy.

[0022] Where a feature is disclosed with respect to a particular aspect of the invention (for example a composition of the invention), such disclosure is also to be considered to apply to any other aspect of the invention (for example a method of the invention) mutatis mutandis.

[0023] Numerical ranges expressed in the format "x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "x to y", it is understood that all ranges combining the different endpoints are also contemplated. P0000155W01 CPL

[0024] 3

[0025] The use of any and all examples or exemplary language e.g. “such as” provided herein is intended merely to better illuminate the invention and does not in any way limit the scope of the invention otherwise claimed.

[0026] "Skin care composition" as used herein is meant to include a composition for topical application to the skin of mammals, especially humans. Such a composition could be of the leave-on or of the wash-off type. Wash-off type is sometimes also referred to as rinse-off type. A leave-on composition means a composition that is applied to the desired skin surface and left on for example from one minute to 24 hours, after which it may be wiped or rinsed off with water, usually during the regular course of personal washing. A wash-off composition means a composition that is applied to the desired skin surface for a shorter period, for example, a few seconds or minutes and usually contains sufficient surfactants that aids in cleaning the surface which may be rinsed off with copious amounts of water. Preferably, the skin care composition of the present invention is a leave-on composition.

[0027] "Skin" as used herein is meant to include skin on the face and body (e.g. neck, chest, back, arms, underarms, hands, legs, buttocks and scalp), and in particular the sun exposed portions thereof.

[0028] “Silicone elastomer” as used herein means cross-linked silicone polymer which swells significantly in a solvent forming a space-filling material which behaves as a visco-elastic soft solid. Generally, the silicone elastomers are used in a blend of silicone elastomer and solvent, which is a dispersion of the silicone elastomer in the solvent.

[0029] “Rubber seed oil” (RSO) is extracted from the seed of rubber tree (Hevea brasiliensis). Typically, rubber tree is widely grown in Yunan, Guangdong and Hainan Provinces of China. In RSO, the levels of total unsaturated fatty acids (UFA) and polyunsaturated fatty acids (PUFA) can amount to more than 80% and 50%, respectively. Irrespective of the oil source, the fatty acid composition of RSO is fairly constant. The main fatty acid composition of RSO includes approximately 14 to 30% of linolenic acid, 30 to 42% of linoleic acid, 20 to 30% of oleic acid, and about 20% of saturated fatty acid by weight. P0000155W01 CPL

[0030] 4

[0031] Silicone Elastomer

[0032] The present invention relates to a silicone elastomer obtainable by a hydrosilylation reaction of: a) an organopolysiloxane having at least two Si-H bonds; and b) rubber seed oil; in the presence of a hydrosilylation catalyst.

[0033] The term “organopolysiloxane” as used herein refers to polymers comprising any number of siloxane units independently selected from (RaSiOo.s), (R2SiO), (RSiOi.s), or (SiCh) siloxy units where R may be any monovalent organic group.

[0034] The organopolysiloxane may have a linear, branched, cyclic or cross-linked structure, preferably a linear structure.

[0035] The organopolysiloxane suitable for use in the present invention comprises at least two Si-H bonds. The term “Si-H” as used herein refers to a hydrogen atom that is covalently bonded to a silicon atom in a siloxyl or silyl group or unit of an organopolysiloxane molecule. The Si-H bonds of the organopolysiloxane may be located at the ends, in the side chains, or at other positions of the molecular chain.

[0036] Preferably, the organopolysiloxane comprises two terminal Si-H bonds. The term “terminal Si-H” as used herein means that the Si-H bonds are located at the ends of an organopolysiloxane chain.

[0037] Preferably, the organopolysiloxane has a formula of HR2SiO-[R2SiO]x-SiR2H, where each R is independently a hydrogen, a C1-C20 alkyl group, or an aryl group; and where x is an integer having a value ranging from 6 to 1400. More preferably, each R is independently a methyl, a C10-C18 alkyl group, a benzyl or a phenyl group; and where x is an integer having a value ranging from 6 to 1400. Even more preferably, each R is independently a methyl, a C12, C14, C16, or Cis alkyl group, and where x is an integer having a value ranging from 6 to 1400.

[0038] Preferably, the organopolysiloxane is hydride terminated polydimethylsiloxane. Preferably, the hydride terminated polydimethylsiloxane comprises 6 to 1400 units, more preferably 8 to 700 units, and even more preferably 10 to 300 units of dimethylsiloxane. P0000155WG1 CPL

[0039] 5

[0040] Blend

[0041] The present invention also relates to a blend comprising the silicone elastomer of the present invention and a solvent.

[0042] Preferably, the solvent is selected from the group consisting of a hydrocarbon oil, a silicone oil, an ester, an ether, an alcohol and mixtures thereof. More preferably, the solvent is selected from the group consisting of a hydrocarbon oil, a silicone oil, an ester and mixtures thereof.

[0043] Preferably, the solvent is a hydrocarbon oil. Hydrocarbon oils suitable for use in the present invention include mineral oils and polyalphaolefins. Illustrative but non-limiting examples of hydrocarbon oils include undecane, tridecane, isodecane, isohexadecane, isododecane, Cy-Cs to C12-C15 isoparaffins and any mixtures thereof. Examples of commercially available hydrocarbon oils include Cetiol® Ultimate from BASF which is the mixture of undecane and tridecane, Entrada® DF (C11-C18 branched and linear alkane), EMOSMART® L15 (C13-C15 alkane) and EMOGREEN® L15 (C15-C19 alkane) from Seppic, LexFeel® WOW-DT from Index which is heptyl undecylenate and C13-C16 isoparaffin. Preferably, the hydrocarbon oil is an alkane, and more preferably an alkane having a carbon chain length of 6 to 28 carbon atoms. Most preferably, the hydrocarbon oil is undecane, tridecane or a mixture thereof.

[0044] Preferably, the solvent is a silicone oil. Silicone oils are preferably volatile silicone oils. The volatile silicone oil according to the present invention has a vapor pressure at 25 °C from 2.6 to 1400 Pa. Particularly preferred silicone volatile oils are linear siloxanes containing 3 to 9 silicon atoms and cyclic siloxanes containing 4 to 6 silicon atoms, such as cyclopentasiloxane. Examples of commercially available volatile silicone oils include oils having grades 344, 345, 244, 245 and 246 from Dow Corning Corporation. Suitable non-volatile silicone oils commonly comprise linear alkyl / aryl methicones such as that available from Dow Corning Inc under their mark DC556 or DC704 and linear methicones of higher viscosity than volatile silicones such as those within the range available from Dow Corning Inc under their trademark DC200 having a viscosity of at least 5 centistokes (cSt). Preferably, the silicone oil is hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, methyl trimethicone, dimethicone or mixtures thereof.

[0045] Preferably, the solvent is an ether. Ethers suitable for use in the present invention include liquid aliphatic ethers, for example, alkyl ethers of polypropylene glycol (PPG), the alkyl group comprising from 2 to 20 carbon atoms and the PPG moiety comprising from 10 to 20, and P0000155WG1 GPL

[0046] 6 particularly 14 to 18 propylene glycol units; dialkyl ethers derived from Cs or Gw linear aliphatic alcohols, especially dioctyl ethers. Preferred ethers include dioctyl ethers, polypropylene glycol alkyl ethers such as PPG-14-butyl ether and PPG-15-stearyl ether. Preferably, the ether is an aliphatic Ge to C30 ether, and more preferably a dioctyl ether.

[0047] Generally, silicone elastomer gels are made available and used in the form of a blend of the silicone elastomer and a solvent which is a dispersion of the silicone elastomer in the solvent. The blends of silicone elastomer and solvent are cross-linked gels that can be prepared by a hydrosilylation reaction. The reaction involves low levels of catalyst, usually platinum derivatives, and is generally run into an adequate solvent.

[0048] Under a shearing force, the silicone elastomer swells in the presence of the solvent. In the finished product, for example, in a skin care lotion, it may not be possible to identify that the silicone elastomer and the solvent for the silicone elastomer were introduced / added together as a blend but usually when the silicone elastomer is a gel and the solvent is also present in the concerned composition, that itself may serve as an indication that when the composition was prepared, the silicone elastomer and the solvent were co-dosed and the silicone elastomer is in the form of a gel, as opposed to particulate elastomers which might permit the introduction of the elastomer as such in the form of particles.

[0049] When the elastomer and the solvent for the elastomer are introduced as a blend, the formulation scientist needs to know the solid content of the blend so that a calculated amount of the blend can be added to a composition to ensure that the composition contains a desired amount of the elastomer. “Solid content” as used herein refers to the weight percentage of silicone elastomer by weight of the blend in the blend comprising the silicone elastomer and the solvent.

[0050] Preferably, the solid content of the blend is from 2 to 50%, more preferably from 3 to 40%, and most preferably 5 to 30%.

[0051] Preparation Method

[0052] The present invention also relates to a method for preparing the blend of the present invention. The method comprises the step of reacting an organopolysiloxane having at least two Si-H bonds and rubber seed oil in the presence of a hydrosilylation catalyst and a solvent. The solvent is as described above for the blend of the present invention. P0000155W01 CPL

[0053] 7

[0054] Preferably, the method for preparing the blend of the present invention comprises the steps of: a) reacting an organopolysiloxane having at least two Si-H bonds and rubber seed oil in the presence of a hydrosilylation catalyst and a solvent; and b) mixing additional quantities of the solvent.

[0055] Preferably, the molar ratio of Si-H in the organopolysiloxane to alkenyl group in rubber seed oil ranges from 20:1 to 1:5, more preferably from 10:1 to 1 :3, and even more preferably from 5:1 to 1:2. “Alkenyl group” as used herein include, but are not limited to, vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group and heptenyl group.

[0056] Preferably, the weight ratio of the organopolysiloxane having at least two Si-H bonds to the rubber seed oil ranges from 10:1 to 1000:1, more preferably from 30:1 to 500:1, and even more preferably from 40:1 to 300:1.

[0057] Preferably, the solvent is present in an amount of 10 to 90% by weight of the reaction mixture. The reaction mixture refers to the mixture of the organopolysiloxane, rubber seed oil, the hydrosilylation catalyst and the solvent used in the reaction.

[0058] Preferably, the hydrosilylation catalyst is a platinum group metal-containing catalyst. The term “platinum group” as used herein means ruthenium, rhodium, palladium, osmium, iridium and platinum and complexes thereof. More preferably, the catalyst is a platinum-containing catalyst. The platinum-containing catalyst can be platinum metal, platinum metal deposited on a carrier such as silica gel or powdered charcoal, or a compound or complex of a platinum group metal. Preferred platinum-containing catalysts include chloroplatinic acid, either in hexahydrate form or anhydrous form, and or a platinum-containing catalyst which is obtained by a method comprising reacting chloroplatinic acid with an aliphatically unsaturated organosilicon compound. Examples of preferred catalyst includes those that are commercially available such as Speier's catalyst, Karstedt's catalyst, Trost Catalyst and Wilkinson Catalyst.

[0059] The appropriate amount of the catalyst will depend upon the particular catalyst used. Preferably, the platinum-containing catalyst is present in an amount of 0.1 to 200 parts per million (ppm), more preferably 1 to 50 ppm, by weight of the reaction mixture. P0000155W01 CPL

[0060] 8

[0061] The temperature of the reaction may vary. Preferably, the reaction is carried out at a temperature between 45°C to 75 °C, and more preferably 50 to 70 °C. Preferably, the reaction is carried out for 2 to 10 hours, and more preferably 4 to 8 hours. Most preferably, the reaction is carried out at a temperature of 60 °C for 4 hours.

[0062] Another aspect of the invention relates to a blend that is obtained by the present method.

[0063] Skin Care Composition

[0064] The present invention further relates to a skin care composition comprising the blend of the present invention.

[0065] Preferably, the blend is present in an amount of 0.1 to 60%, more preferably 1 to 40%, and most preferably 2 to 30% by weight of the composition.

[0066] Preferably, the skin care composition further comprises an emollient oil. Preferably, the emollient oil is selected from the group consisting of silicone, hydrocarbon, fatty acid, fatty alcohol, ester and mixtures thereof.

[0067] Preferred silicone emollient oils may be organic, silicone-containing or fluorine-containing, volatile or non-volatile, polar or non-polar emollient oils. Preferably, the emollient oil comprises silicone which is not the silicone elastomer according to the present invention. Preferably, the emollient oil is chosen from cyclic (cyclomethicone) or linear polydimethylsiloxanes containing from 3 to 9, preferably from 4 to 5 silicon atoms.

[0068] Preferred hydrocarbon emollient oils may be wax, cyclic hydrocarbons, straight chain aliphatic hydrocarbons (saturated or unsaturated), or branched chain aliphatic hydrocarbons (saturated or unsaturated). Illustrative examples include, but are not limited to, mineral oil, wax, petrolatum (such as petroleum jelly) or mixtures thereof. Preferably, the emollient oil is mineral oil, undecane, tridecane or mixtures thereof.

[0069] Preferred fatty acid emollient oils often have from 10 to 30 carbon atoms.

[0070] Preferred fatty alcohol emollient oils often have from 10 to 30 carbon atoms. P0000155W01 CPL

[0071] 9

[0072] Preferred ester emollient oils may be selected from mono-, di- or triglycerides such as vegetable and animal fats and oils; acetyl glycerides; ethoxylated glycerides such as ethoxylated glyceryl monostearate; alkyl esters of fatty acids having 10 to 20 carbon atoms such as methyl, isopropyl and butyl esters of fatty acids; alkenyl esters of fatty acids having 10 to 20 carbon atoms; ether-esters such as fatty acid esters of ethoxylated fatty alcohols; polyhydric alcohol esters; and wax esters. Preferred triglyceride is one or more of almond oil, apricot kernel oil, avocado oil, arnica oil, castor oil, cotton seed oil, coconut oil, evening primrose oil, groundnut oil, jojoba oil, macadamia oil, palm oil, rape seed oil, rice bran oil, safflower oil, soybean oil, sunflower oil, shea butter or wheatgerm oil. Preferably, the emollient oil is caprylic / capric triglyceride, dicaprylyl carbonate, sunflower oil, isopropyl myristate or mixtures thereof.

[0073] Suitable examples of preferred emollient oils are as follows: acetoglyceride esters: acetylated monoglycerides; alkyl esters: methyl, isopropyl, and butyl esters of fatty acids; hexyl laurate, isohexyl laurate, isopropyl myristate, isopropyl palmitate, decyl oleate, isodecyl oleate, hexadecyl (isocetyl) stearate, diisopropyl adipate, diisohexyl adipate, dihexadecyl adipate, diisopropyl sebacate, lauryl lactate, myristyl lactate, and cetyl lactate; alkenyl esters: oleyl myristate, oleyl stearate, and oleyl oleate; fatty acids: lauric, myristic, palmitic, stearic, isostearic, hydroxystearic, oleic, linoleic, linolenic, gamma. -linolenic, ricinoleic, arachidic, behenic, erucic, and lanolin acids; polyhydric alcohol esters: ethylene glycol mono and di-fatty acid esters, diethylene glycol mono- and di-fatty acid esters, polyethylene glycol (200-6000) mono- and di-fatty acid esters, propylene glycol mono- and di-fatty acid esters, polypropylene glycol 2000 monooleate, polypropylene glycol 2000 monostearate, ethoxylated propylene glycol monostearate, glyceryl mono- and di-fatty acid esters, polyglycerol poly-fatty esters, ethoxylated glyceryl mono-stearate, 1 ,3-butylene glycol monostearate, 1,3-butylene glycol distearate, polyoxyethylene polyol fatty acid ester, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters; fatty alcohols: lauryl, myristyl, cetyl, hexadecyl (isocetyl), stearyl, isostearyl, hydroxystearyl, oleyl, ricinoleyl, behenyl and erucyl alcohols, and 2-octyl dodecanol; fatty alcohol ethers: ethoxylated lauryl, cetyl, stearyl, isostearyl, oleyl, and lanolin alcohols; and cholesterol; propoxylated cetyl, oleyl, and lanolin alcohols; and polypropylene-15-stearyl ether; ether-esters: fatty acid esters of ethoxylated fatty alcohols; P0000155W01 CPL

[0074] 10 lanolin and lanolin derivatives: lanolin, lanolin oil, lanolin wax, lanolin alcohols, lanolin fatty acids and acetylated lanolin derivatives; wax esters: beeswax, spermaceti, myristyl myristate, stearyl stearate; beeswax derivatives: polyoxyethylene sorbitol beeswax. These are reaction products of beeswax with ethoxylated sorbitol of varying ethylene oxide content, forming a mixture of ether-esters; vegetable waxes: carnauba, candelilla; phopholipids: lecithin and derivatives; and sterols: cholesterol and cholesterol fatty acid esters.

[0075] Preferably, the emollient oil is present in an amount of 0.01 to 20%, more preferably 0.1 to10%, and even more preferably 1 to 8% by weight of the composition.

[0076] Preferably, the composition further comprises a whitening pigment. Whitening pigments are typically particles of high refractive index materials. For example, the whitening pigment may have a refractive index of greater than 1.3, more preferably greater than 1.8 and most preferably from 2.0 to 2.7. Examples of such whitening pigment are those comprising bismuth oxy-chloride, boron nitride, barium sulfate, mica, silica, titanium dioxide, zirconium oxide, aluminum oxide, zinc oxide or combinations thereof. More preferred whitening pigment are particles comprising titanium dioxide, zinc oxide, zirconium oxide, mica, iron oxide or a combination thereof. Even more preferred whitening pigment are particles comprising zinc oxide, zirconium oxide, titanium dioxide or a combination thereof as these materials have especially high refractive index. Still even more preferably, the whitening pigment is selected from titanium dioxide, zinc oxide or a mixture thereof and most preferred whitening pigment is titanium dioxide. The average diameter of whitening pigment is typical from 15 nm to 1 micron, more preferably from 35 nm to 800 nm, even more preferably from 50 nm to 500 nm and still even more preferably from 100 to 300 nm.

[0077] Preferably, the composition further comprises an organic sunscreen. The organic sunscreen can be oil soluble or water-soluble, preferably oil soluble. The oil soluble organic sunscreen is preferably selected from the class comprising cinnamic acid, salicylic acid, diphenylacrylic acid or derivatives thereof.

[0078] Preferably, the organic sunscreen is selected from, 2-hydroxy-4-methoxybenzophenone, octyldimethyl p-aminobenzoic acid, digalloyltrioleate, 2,2-dihydroxy-4-methoxybenzophenone, P0000155WG1 GPL

[0079] 11 ethyl-4-(bis(hydroxypropyl))aminobenzoate, 2-ethylhexyl-2-cyano-3,3-diphenylacrylate, 2- ethylhexylsalicylate, glyceryl p-aminobenzoate, 3,3,5-trimethylcyclohexyl salicylate, methylanthranilate, p-dimethylaminobenzoic acid or aminobenzoate, 2-ethylhexyl-p- dimethylaminobenzoate, 2-phenylbenzimidazole-5-sulfonic acid, 2-(p-dimethylaminophenyl)-5- sulfonicbenzoxazoic acid, 2-ethylhexyl-p-methoxycinnamate, dibenzoylmethane derivatives, 2- hydroxy-4-methoxybenzophenone, octyldimethyl-p-aminobenzoic acid, diethylhexyl naphthylate, Mexoryl™, Tinosorb S™, Tinosorb M™ and mixtures thereof. More preferably, the organic sunscreen is 2-ethylhexyl-p-methoxycinnamate, butylmethoxydibenzoylmethane or a mixture thereof. Even more preferably, the organic sunscreen is 2-ethylhexyl-p-methoxycinnamate.

[0080] Preferred organic sunscreens that are commercially available include Octisalate™ (octyl salicylate), Homosalate™ (3,3,5-trimethylcyclohexyl-2-hydroxybenzoate), Neo Heliopan™ (a number of organic UV filters, including ethylhexylmethoxycinnamate (Neo Heliopan AV) and ethylhexylsalicylate (Neo Heliopan OS)), Octocrylene™ (2-ethylhexyl-2-cyano-3,3-diphenyl-2- propenoate), Parsol 1789™ (4-tert-butyl-4'-methoxydibenzoylmethane), and Parsol MCX™ (2- ethylhexyl-4-methoxycinnamate or octyl methoxy cinnamate).

[0081] Preferably, the organic sunscreen is present in an amount from 0.001 to 15%, more preferably from 0.01 to 10%, and even more preferably from 0.1 to 8%, by weight of the composition.

[0082] The composition of the invention preferably comprises a skin lightening agent. Vitamin B3 compounds (including derivatives of vitamin B3) e.g. niacin, nicotinic acid or niacinamide are the preferred skin lightening agent as per the invention, most preferred being niacinamide. Other well-known skin lightening agents include adapalene, aloe extract, ammonium lactate, anethole derivatives, apple extract, arbutin, azelaic acid, kojic acid, bamboo extract, bearberry extract, bletilla tuber, bupleurum falcatum extract, burnet extract, butyl hydroxy anisole, butyl hydroxy toluene, citrate esters, Chuanxiong, Dang-Gui, deoxyarbutin, 1 ,3-diphenyl propane derivatives, 2,5-dihydroxybenzoic acid and its derivatives, 2-(4-acetoxyphenyl)-1 ,3-dithane, 2- (4-hydroxyphenyl)-1,3-dithane, ellagic acid, escinol, estragole derivatives, Fadeout (Pentapharm), Fangfeng, fennel extract, ganoderma extract, gaoben, Gatuline Whitening (Gattlefosse), genistic acid and its derivatives, glabridin and its derivatives, gluco pyranosyl-1- ascorbate, gluconic acid, glycolic acid, green tea extract, 4-hydroxy-5-methyl-3[2H]-furanone, hydroquinone, 4-hydroxyanisole and its derivatives, 4-hydroxy benzoic acid derivatives, hydroxycaprylic acid, inositol ascorbate, lemon extract, linoleic acid, magnesium ascorbyl phosphate, Melawhite (Pentapharm), Morus alba extract, mulberry root extract, 5-octanoyl P0000155W01 CPL

[0083] 12 salicylic acid, parsley extract, Phellinus linteus extract, pyrogallol derivatives, 2,4-resorcinol derivatives, 3,5-resorcinol derivatives, rose fruit extract, salicylic acid, Song-Yi extract, 3,4,5- tri hydroxy benzyl derivatives, tranexamic acid, vitamins like vitamin B6, vitamin B12, vitamin C, vitamin A, dicarboxylic acids, resorcinol derivatives, extracts from plants viz. Rubia and Symplocos, hydroxycarboxylic acids like lactic acid and their salts e.g. sodium lactate, and mixtures thereof.

[0084] When present in the composition according to the invention, the skin lightening agent may, for example, be present in an amount of 0.001 to 10%, preferably 0.01 to 5%, and more preferably 0.1 to 3%, by weight of the composition.

[0085] The skin care composition of the present invention may further comprise a wide range of other ingredients which are common in the art to enhance physical properties and performances. The CTFA Cosmetic Ingredient Handbook, Second Edition, 1992, which is incorporated by reference herein in its entirety, describes a wide variety of non-limiting cosmetic and pharmaceutical ingredients commonly used in the skin care industry, which are suitable for use in the compositions of the present invention.

[0086] Suitable ingredients include but are not limited to antioxidants, binders, biological additives, buffering agents, colorants, conditioners, fragrance, humectants, opacifiers, pH adjusting agents, pigments, preservatives, surfactants, thickeners, viscosity modifiers, essential oils, natural extracts, skin sensates, skin soothing agents, and / or skin healing agents.

[0087] The skin care composition may take a variety of forms, including a cream, gel, aerosol, spray, lotion, milk, foam, paste, emulsion, water-in-oil (W / O) emulsion, oil-in-water (O / W) emulsion, or multiphase emulsion and so on, together with a suitable excipient, carrier, or propellant.

[0088] Preferably, the skin care composition is an oil-in-water (O / W) emulsion. Preferably, the water content is from 5 to 95%, more preferably from 15 to 90%, even more preferably from 20 to 85%, and most preferably from 40 to 80%, by weight of the composition.

[0089] The following examples are provided to facilitate an understanding of the invention. The examples are not intended to limit the scope of the claims. P0000155W01 CPL

[0090] 13

[0091] Examples

[0092] Example 1 - Preparation of Blends Comprising RSO Based Silicone Elastomer and Solvent

[0093] Materials

[0094] Rubber seed oil: Rubber seed oil (RSO), supplied by XISHUANGBANNA HUAKUN BIOTECH CO., LTD.

[0095] Organopolysiloxane having at least two Si-H bonds: Andisil® CE500 is dimethylhydrogen terminated polydimethylsiloxane (0.16mmol SiH / gm), supplied by AB Specialty Silicones. Solvent: Cetiol® Ultimate (undecane (and) tridecane), supplied by BASF.

[0096] Hydrosilylation catalyst: Karstedt’s catalyst is platinum tetravinyldisiloxane in 500 cSt vinyl teminated poly dimethysiloxane (platinum content 0.5%), supplied by Johnson Matthey.

[0097] Samples in accordance with the present invention were prepared as shown in Table 1.

[0098] Table 1

[0099] Method

[0100] Sample 1 was prepared using 18.0 g Andisil® CE500, 0.3 g rubber seed oil (RSO), and 34.8 g Cetiol® Ultimate, with all the ingredients charged into a 100 mL beaker. The mixture was mechanically stirred for 10 minutes, and the temperature was increased to 60°C. 0.7 g Karstedt’s catalyst was added to the mixture and stirred at a temperature of 60 °C. The blend according to the present invention comprising silicone elastomer and solvent was formed in 2 hours.

[0101] For Sample 2, additional 37.7 g Cetiol® Ultimate was added in the reaction mixture, and stirring was performed for 30 minutes to make sure the solvent was fully swelled.

[0102] Rheology Measurement

[0103] Rheology of the above samples was measured using a Rheometer (Anton Paar, Physica MCR 301) with a parallel plate measuring system. Amplitude sweep measurement was conducted P0000155WG1 CPL

[0104] 14 and 25 mm geometry PP25 / TG with a gap of 0.5 mm was used. After loading, the samples were left to equilibrate for 3 minutes, and then oscillated at 10 rad / s with increasing strain amplitude from 0.001 to 100%.

[0105] Typically, the storage modulus (initial G') represents elasticity and hardness. The failure point (FP, strain %) with percent strain represents stability and resilience of the swollen structure of the blends. Generally, for internally prepared silicone elastomers in skin care application, acceptable initial G' ranges from 800 Pa to 4000 Pa. For FP, above 10% strain means good swelling structure stability.

[0106] Result

[0107] The Initial G' (Pa) and the FP (strain %) values of each sample were recorded and provided in Table 2.

[0108] Table 2

[0109] As shown in Table 2, the initial G’ and FP values of both Sample 1 and 2 in accordance with the present invention indicated acceptable hardness and resilience. Sample 2 of a lower solid content was softer and less resilient as compared to Sample 1.

[0110] Example 2 - Compatibility Test

[0111] This example demonstrates the compatibility of the blend of the present invention with different emollient oils.

[0112] Preparation of Samples A to C and 3

[0113] Materials

[0114] Andisil® XL-15 is silicon-hydride containing polysiloxanes (3.15 mmoles / gm), supplied by AB Specialty Silicones.

[0115] Andisil® XL-10 is silicon-hydride containing polysiloxanes (7.55 mmoles / gm), supplied by AB Specialty Silicones.

[0116] Andisil® CE500 is dimethylhydrogen terminated polydimethylsiloxane (0.16mmol SiH / gm), supplied by AB Specialty Silicones. P0000155W01 CPL

[0117] 15

[0118] Andisil® VS-200 is vinyl-terminated dimethylpolysiloxanes (0.25 mmoles / gm), supplied by AB Specialty Silicones.

[0119] Andisil® SF-2430 is vinyl-terminated dimethyl diphenyl polysiloxanes, supplied by AB Specialty Silicones.

[0120] Sunflower oil (SFO), supplied by CARGILL.

[0121] Rubber seed oil (RSO), supplied by XISHUANGBANNA HUAKUN BIOTECH CO., LTD.

[0122] 1-Dodecene, supplied by Tokyo Chemical Industry Co., Ltd. (TCL).

[0123] Cetiol® Ultimate is undecane (and) tridecane, supplied by BASF.

[0124] DC245 has the INCI Name of cyclopentasiloxane, supplied by the Dow Chemical Company. Karstedt’s catalyst is platinum tetravinyldisiloxane in 500 cSt vinyl teminated poly dimethysiloxane (platinum content 0.5%), supplied by Johnson Matthey.

[0125] 1. Preparation of Sample A - V1.5 Elastomer

[0126] 0.70 g Andisil® XL-15, 15.60 g Andisil® VS-200, and 31.55 g Cetiol® Ultimate were charged into a 250 ml wide neck flask, and the mixture was stirred at room temperature for 10 minutes. The mixture was heated to 60 °C, and 0.10 g Karstedt’s catalyst was added. The reaction was carried out for 2 hours at 60 °C with mechanical stirring at 200 rpm. The gelled mixture was diluted to a solid content of 20% by adding 33.56 g Cetiol® Ultimate at 60 °C after the reaction was completed to obtain Sample A

[0127] 2. Preparation of Sample B - FEL Elastomer

[0128] 0.68 g Andisil® XL-10, 0.37 g 1-dodecene and 1.09 g DC245 were mixed and stirred in a vial, followed by the addition of 0.004 g Karstedt’s catalyst. The mixture was stirred at 60 °C for 30 mins. 39.65 g DC245, 20.00 g Andisil® SF-2430 and 0.12 g Karstedt’s catalyst were added to the mixture. Then the mixture was kept at 60 °C with the reflux of water and stirred at 200 rpm for 4 hours. The gelled mixture was diluted to a solid content of 20% by adding 43.34 g DC245 at 60 °C after the reaction was completed to obtain Sample B.

[0129] 3. Preparation of Sample C - SFO Based Elastomer

[0130] 18.00 g Andisil® CE500, 0.30 g sunflower oil (SFO) and 34.74 g Cetiol® Ultimate were charged into a 100 mL beaker. The mixture was mechanically stirred for 10 minutes, and the temperature was increased to 60 °C. 0.78 g Karstedt’s catalyst was added to the mixture and stirred at 60 °C. The SFO based elastomer formed in 2h. The gelled mixture was diluted to a solid content of 20% by adding 37.68 g Cetiol® Ultimate at 60 °C after the reaction was completed to obtain Sample C. P0000155W01 CPL

[0131] 16

[0132] 4. Preparation of Sample 3 - RSO Based Silicone Elastomer Blend

[0133] 18.00 g Andisil® CE500, 0.30 g rubber seed oil (RSO), and 34.80 g Cetiol® Ultimate were charged into a 100 mL beaker. The mixture was mechanically stirred for 10 minutes, and the temperature was increased to 60 °C. 0.70 g Karstedt’s catalyst was added to the mixture and stirred at 60 °C. The RSO based silicone elastomer blend formed in 2h. The gelled mixture was diluted to a solid content of 20% by adding 37.70 g Cetiol® Ultimate at 60 °C after the reaction was completed.

[0134] Method

[0135] Each centrifuge tube was charged with 2.00 g of one sample (Sample A-C, Sample 3) and a dose of one emollient oil as indicated in Tables 4 to 6. The mixture was stirred until the emollient oil mixed well with the sample. After the sample became stable, observation was made to evaluate the compatibility of the sample with the emollient oil. The compatibility of each sample with different emollient oils was evaluated following the standards described in Table 3

[0136] Table 3

[0137] Results

[0138] The results for the compatibility test are shown in Table 4 to Table 6.

[0139] Table 4

[0140] 1 : PARSOL® MCX has the INCI name of ethylhexyl methoxycinnamate, supplied by DSM. 2: Mineral oil is low viscosity white mineral oil, supplied by Sonneborn. P0000155W01 CPL

[0141] 17

[0142] Table 5

[0143] 1 : Cetiol® CC is dicaprylyl carbonate, supplied by BASF.

[0144] Table 6

[0145] As shown in Table 4 to Table 6, Sample 3 in accordance with the present invention kept homogeneous with all the tested emollient oils even at higher dosages, while Sample A to C already collapsed with oil leak under the same condition. It was surprisingly found that the blend comprising the silicone elastomer of the present invention demonstrated significantly better compatibility.

Claims

P0000155W01 CPL18Claims1. A silicone elastomer obtainable by a hydrosilylation reaction of: a) an organopolysiloxane having at least two Si-H bonds; and b) rubber seed oil; in the presence of a hydrosilylation catalyst.

2. The silicone elastomer according to claim 1 , wherein the organopolysiloxane comprises two terminal Si-H bonds.

3. The silicone elastomer according to claim 1 or 2, wherein the organopolysiloxane has the formula of HR2SiO-[R2SiO]x-SiR2H, where each R is independently a hydrogen, a C1-C20 alkyl group or an aryl group; and where x is an integer having a value ranging from 6 to 1400.

4. The silicone elastomer according to any one of the preceding claims, wherein the organopolysiloxane is a hydride terminated polydimethylsiloxane.

5. The silicone elastomer according to claim 4, wherein the hydride terminated polydimethylsiloxane comprises 6 to 1400 units, preferably 8 to 700 units, of dimethylsiloxane.

6. A blend comprising the silicone elastomer according to any one of the preceding claims 1 to 5 and a solvent.

7. The blend according to claim 6, wherein the solvent is selected from the group consisting of a hydrocarbon oil, a silicone oil, an ester, an ether, an alcohol and mixtures thereof.

8. The blend according to claim 7, wherein the hydrocarbon oil is an alkane, preferably an alkane having a carbon chain length of 6 to 28 carbon atoms.

9. The blend according to claim 7, wherein the silicone oil is hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, methyl trimethicone, dimethicone or mixtures thereof.

10. The blend according to any one of the preceding claims 6 to 9, wherein the solid content of the blend is from 2 to 50%.P0000155W01 CPL1911. A method for preparing the blend according to any one of the preceding claims 6 to 10 comprising the step of reacting: a) an organopolysiloxane having at least two Si-H bonds; and b) rubber seed oil; in the presence of a hydrosilylation catalyst and a solvent.

12. The method according to claim 11, wherein the molar ratio of Si-H in organopolysiloxane to alkenyl groups in rubber seed oil is from 20:1 to 1 :5.

13. A skin care composition comprising the blend according to any one of the preceding claims 6 to 10 or the blend prepared according to claim 11 or 12.

14. The composition according to claim 13, wherein the blend is present in an amount of 0.1 to 60%, preferably 1 to 40%, by weight of the composition.

15. The composition according to claim 13 or 14, wherein the composition further comprises an emollient oil.

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