The invention relates to the use of certain siloxane compounds, more particularly to the use of certain aralkylsiloxane compounds.
The use of phenyltrimethicone in personal care compositions, for example, skin lotions, antiperspirants, hair care products to enhance shine, lubricity and/or visual masking of inorganic components, is known. Typical methods for making phenyltrimethicone, such as for example, by cohydrolysis of phenyltrichlorosilane and chlorotrimethylsilane may introduce impurities, such as for example, side products and catalyst residues, into the phenyltrimethicone product which are undesirable in the context of using the phenyltrimethicone product as a component in a personal care composition.
In a first aspect, the present invention is directed to a method of using of an aralkylsiloxane, comprising adding the aralkylsiloxane as a component in a personal care composition, in an amount effective to enhance one or more properties of the personal care composition. For example, the aralkylsiloxane enhances the shine, emolliency and lubricity of personal care compositions and aids in visually masking inorganic components of such compositions.
In a second aspect, the present invention is directed to a method for making an aralkyl siloxane, comprising contacting a silylhydride-functional polysiloxane with a terminally unsaturated arylalkene under hydrosilylation conditions. Aralkylsiloxanes made by the preferred process exhibit a low, preferably an undetectably low, level of impurities and thus allow the amount of impurities introduced into the personal care composition by addition of such aralkylsiloxanes to be minimized.
In a third aspect, the present invention is directed to a method for making an improved personal care composition, said personal care composition being an analog of a first personal care composition that contains phenyltrimethicone as a component thereof, comprising making a personal care composition analogous to the first personal care composition wherein an aralkylsiloxane is substituted for the phenyltrimethicone of the first personal care composition.
In a preferred embodiment, the personal care composition comprises, based on 100 parts by weight (xe2x80x9cpbwxe2x80x9d) of the personal care composition, from about 0.5 pbw to about 50 pbw, more preferably from about 1 pbw to about 30 pbw, still more preferably from about 2 pbw to about 20 pbw, of the aralkylalkylsiloxane.
Aralkylsiloxanes that are suitable as the aralkylsiloxane component of the present invention are those comprising one or more compounds according to formula (I): 
wherein:
R1, R2, R3, R4, R5, R8 and R9 and R10 are each independently H, alkyl, more preferably (C1-C6)alkyl, haloalkyl, more preferably halo(C1-C6)alkyl, aryl or aralkyl,
R6, R7 are each independently H, alkyl, more preferably (C1-C6)alkyl, haloalkyl, more preferably halo(C1-C6)alkyl, or aryl; n and m are each independently integers from 0 to 6, provided that (n+m)xe2x89xa71, preferably 1xe2x89xa7(n+m)xe2x89xa68, still more preferably 1xe2x89xa6(n+m)xe2x89xa64 and provided that at least one substituent group of the compound of formula (I) is aralkyl; or of formula (II): 
wherein:
R11 and R12 are each independently H, alkyl, more preferably (C1-C6)alkyl, haloalkyl, more preferably halo(C1-C6)alkyl, aryl or aralkyl; R13 and R14 are each independently H, alkyl, more preferably (C1-C6)alkyl, haloalkyl, more preferably halo(C1-C6)alkyl, or aryl; x and y are each independently integers from 0 to 6, provided that 3xe2x89xa6(x+y)xe2x89xa610, preferably 4xe2x89xa6(x+y)xe2x89xa66, and provided that at least one substituent group of the compound of formula (II) is aralkyl.
As used herein, the term xe2x80x9c(C1-C6)alkylxe2x80x9d means a linear or branched alkyl group containing from 1 to 6 carbons per group, such as, for example, methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl, preferably methyl.
As used herein, the term xe2x80x9chalo(C1-C6)alkylxe2x80x9d means a linear or branched alkyl group containing from 1 to 6 carbons per group that is substituted with one or more halo substituents, such as, for example, chloromethyl, trifluoromethyl.
As used herein, the term xe2x80x9carylxe2x80x9d means a monovalent unsaturated hydrocarbon ring system containing one or more aromatic rings per group, which may optionally be substituted on the one or more aromatic rings, preferably with one or more groups selected from amino, nitro, (C1-C6)alkyl, and which, in the case of two or more rings, may be fused rings, including, for example, phenyl, 2,4,6-trimethylphenyl, 2-isopropylmethylphenyl, 1-pentalenyl, naphthyl, anthryl, preferably phenyl.
As used herein, the term xe2x80x9caralkylxe2x80x9d means an aryl derivative of an alkyl group, preferably a (C2-C6)alkyl group, wherein the alkyl portion of the aryl derivative may, optionally, be interrupted by an oxygen atom, such as, for example, phenylethyl, phenylpropyl, 2-(1-naphthyl)ethyl, preferably phenylpropyl, phenyoxypropyl, biphenyloxypropyl.
In a highly preferred embodiment, the aralkylsiloxane comprises a compound according to formula (I), wherein R1 and R10 are each aralkyl, more preferably phenylpropyl, R2, R3, R6, R7, R8 and R9 are each (C1-C6) alkyl, more preferably methyl, n is 0 and 2xe2x89xa6mxe2x89xa65,, more preferably n is 0 and m is 3. In a very highly preferred embodiment, the aralkylsiloxane comprises xcex1,xcfx89-bis(2-phenylpropyl)siloxane.
In a preferred embodiment, the aralkylsiloxane comprises a compound according to formula (I), wherein R1, R2, R3, R4, R6, R7, R8, R9 and R10 are each (C1-C6) alkyl, preferably methyl, R5 is aralkyl, more preferably phenylpropyl, , n is 1 or 2 and 1xe2x89xa6mxe2x89xa68, more preferably, n is 1 and m is 2.
In a preferred embodiment, the aralkyl siloxane comprises a compound according to the structural formula (II), wherein R11, R13 and R14 are each (C1-C6) alkyl, preferably methyl, R12 is aralkyl, more preferably phenylpropyl, 1xe2x89xa6xc3x97xe2x89xa64 and 2xe2x89xa6yxe2x89xa610, more preferably x is 1 and y is 4.
In a highly preferred embodiment, the aralkyl content of the aralklysiloxane is selected to provide a refractive index of from 1.40 to 1.50, more preferably from about 1.44 to 1.48, at 25xc2x0 C. In a highly preferred embodiment, the aralkylsiloxane comprises, based on the molecular weight of the aralkylsiloxane, from about 25 to about 65 percent by weight (xe2x80x9cwt %xe2x80x9d), more preferably from about 30 to about 50 wt % and still more preferably from about 33 to about 45 wt %, of one or more aralkyl substituent groups.
Suitable aralkylsiloxane can be made by known methods, see, for example, U.S. Pat. Nos. 3,088,964 and 5,300,669 and 5,384,383, the disclosures of which are each incorporated herein by reference.
In a preferred embodiment, the aralkylsiloxane is made by contacting a silylhydride-functional polysiloxane with an terminally unsaturated arylalkene, such as for example, styrene or 2-phenylpropene, under hydrosilylation conditions, preferably in the presence of a solid hydrosilylation catalyst. In a preferred embodiment, the solid hydrosiliylation catalyst comprises a catalytically active metal, such as for example, platinum, supported on an inert support, such as for example, alumina. Preferably, the aralkylsiloxane product exhibits a hydride content of less than 100 parts per million (xe2x80x9cppmxe2x80x9d), based on the weight of aralkylsiloxane. The catalyst and excess arylalkene may be easily removed form the product mixture to yield an aralkylsiloxane having a low to undetectably low content of impurities. In a preferred embodiment, the solid catalyst is removed from the aralkylsiloxane product by filtration. Excess arylalkene may be removed by heating the product mixture by vacuum stripping the aralkylsiloxane.
The personal care applications in which an aralkylalkylsiloxane may be employed include, but are not limited to, deodorants, antiperspirants, skin lotions, moisturizers, hair care products such as shampoos, hair conditioners, mousses, hair sprays and styling gels, protective compositions such as sunscreens, skin treatments and anti-aging products, color cosmetics such as lipsticks, foundations, blushes, makeup, and mascaras; and other cosmetic formulations, as well as drug delivery systems for topical application of medicinal compositions that are to be applied to the skin. Suitable personal care compositions are made by combining, according to methods known in the art, one or more of the above components with an aralkylalkylsiloxane.
In a preferred embodiment, suitable for example, as an after bath oil composition, the personal care composition of the present invention comprises a mineral oil and an aralkylsiloxane.
In a preferred embodiment, suitable for example, as a hair conditioner composition, the personal care composition of the present invention comprises a suitable solvent, such as for example, isododecane, isohexadecane or cyclomethicone and an aralkylsiloxane.
In a preferred embodiment, suitable for example, as a skin care composition, the personal care composition of the present invention comprises the aralkylsiloxane and a nonaqueous medium, comprising for example one or more of organic oils, such as sunflower seed oil and octyldodecylneopentanoate, and silicone oils, such as dimethicone and cyclomethicone, or with an aqueous medium, preferably in the form of an emulsion. Preferably the skin care composition further comprises one or more suitable emulsifiers, such as, for example, fatty acid esters, sorbitan derivatives such as sorbitan sesquioleate, sorbitan oleate, sorbitan isostearate, polyglyceryl-3 oleate, alkoxylated alcohols such as laureth-4, laureth-7, deceth-12, steareth-10, hydroxylated or alkoxylated derivatives of silicone compounds such as dimethicone copolyol, cetyl dimethicone copolyol, and lauryl methicone copolyol and glyceryl esters such as polyglyceryl-4-isostearyl.
In a preferred embodiment, suitable as an anti-perspirant composition the personal care composition of the present invention comprises one or more active anti-perspirant agents, such as, for example, aluminum halides, aluminum hydroxyhalides, for example, aluminum chlorohydrate, and complexes or mixtures thereof with zirconyl oxyhalides and zirconyl hydroxyhalides, such as for example, aluminum-zirconium chlorohydrate, and an aralkylsiloxane.
In a preferred embodiment, suitable, for example, as a sunscreen composition, the personal care composition of the present invention comprises one or more absorbing or blocking agents for ultraviolet radiation, such as, for example, titanium dioxide, p-aminobenzoic acid and oxybenzone sunscreens, such as benzophenone-3 and an aralkylsiloxane. In a preferred embodiment, the sunscreen composition is in the form of an aqueous emulsion, further comprising water and one or more emulsifiers.
The personal care composition of the present invention may, optionally, further contain such known components as, for example, emollients, moisturizers, humectants, pigments, colorants, fragrances, biocides, preservatives, exfoliants, hormones, enzymes, medicinal compounds, anti-microbial agents, anti-fungal agents, vitamins, salts, electrolytes, alcohols, polyols, absorbing or blocking agents for ultraviolet radiation, botanical extracts, surfactants, emulsifiers, silicone oils, organic oils, waxes, thickening agents such as, for example, acrylic polymers, fumed silica or hydrated silica, clays, such as, for example, bentonite, and organo-modified clays.