Cosmetic compositions comprising water-in-oil emulsion containing pigment.

0001The present invention relates to cosmetic compositions in general, and more specifically, to compositions of a water-in-oil emulsion containing other cosmetically desirable components and pigment.

0002U.S. Patent No. 4,532,132 discloses certain polyoxyalkylene-substituted siloxanes, and compositions containing said siloxanes and mineral oil. The patent does not, however, suggest how to incorporate high loadings of pigment nor of other siloxane components such as dimethyl­siloxane.

0003U.S. Patent No. 4,311,695 discloses water-in-oil emulsions useful in the practice of the present invention.

0004The present invention comprises a cosmetic composition which is a water-in-oil emulsion comprising <ul id="ul0001" list-style="none"><li>(a) an oil phase which comprises <ul id="ul0002" list-style="none"><li>(i) a coated pigment consisting essentially of finely divided particles of pigment (inorganic or organic) whose surfaces are chemically bonded to, and physically completely coated by, polysiloxane which coating renders the particles hydrophobic, and</li><li>(ii) a silicone component selected from the group consisting of dimethyl polysiloxane having the formula (CH₃)SiO(Si(CH₃)₂O)_d-Si(CH₃)₃ wherein the degree of polymerization d is effective to give the fluid a viscosity of 0.65 to one million centistokes at 25°C.; cyclomethicone having a degree of polymerization of 3 to 6; organopolysiloxane having the formula X(CH₃)₂SiO-Y-Si(CH₃)₂X wherein X is alkyl or alkoxy having 1 to 30 carbon atoms and Y is a chain of 1 to 100 repeating (Si-O) units containing 1 to 100 units of the formula (-Si(R₁)(R₂)O-) and 0 to 100 units of the formula (Si(R₃)(R₄)O) wherein each of R₁,R₂,R₃ and R₄ can be alkyl containing 2 to 30 carbon atoms, phenyl, or phenyl connected to the Si atom by a vinyl group or an alkylene bridge 1 to 3 carbon atoms long; wherein each R₁ and R₃ can also be -CH₃, and each R₁ and R₂ can also be trimethylsiloxy; and mixtures thereof;</li></ul></li><li>(b) an aqueous phase;</li><li>(c) a surfactant which is a polydiorgano­siloxane-polyoxyalkylene copolymer containing at least one polydiorganosiloxane segment consisting of R_bSiO_(4-b)/2 siloxane units wherein b has a value of from 0 to 3 inclusive, there being an average of approximately 2 R radicals per silicon in the copolymer, and R denotes a radical select from the group consisting of methyl, ethyl, vinyl, phenyl and a divalent radical of 2-6 carbons bonding a polyoxyalkylene segment to the polydiorgano­siloxane segment, at least 95 percent of all R radicals being methyl; and containing at least one polyoxyalkylene segment having an average molecular weight of less than 5000 and consisting of from 0 to 50 mol percent polyoxy­propylene units and from 50 to 100 mol percent polyoxy­ethylene units, at least one terminal portion of said polyoxyalkylene segment being bonded to said polydiorgano­siloxane segment, any terminal portion of said polyoxy­alkylene segement not bonded to said polydiorganosiloxane segment being satisfied by a terminating radical; and said surfactant component being present in an amount effective to form a stable emulsion of said water phase in said oil phase.</li><li>(d) Optionally a second organic surfactant which is silicone-free; and has an HLB value of 2 to 12; wherein all of the surfactant components are present in an amount effective to form a stable emulsion of said oil phase in said water phase.</li></ul>

0005The cosmetic compositions of the present invention are useful in a variety of makeup products such as foundations, eyeshadows, blushes, and the like.

0006The oil phase preferably contains as the major component one or both of dimethyl polysiloxane having the chemical formula (1) (CH₃)₃SiO(Si(CH₃)₂O)_d-Si(CH₃)₃      (1) in which the degree of polymerization d has a value, typically between 1 and 4160, effective to give the fluid a viscosity of 0.65 to one million centistokes at 25°C; and/or a cyclomethicone having D = 3 to 6 repeating units of formula (1): -(Si(CH₃)₂O)_D-      (2)

0007The dimethyl polysiloxane or cylomethicone, or the sum when both are present, preferably is up to 95 or even 97 weight percent of the oil phase.

0008The hydrophobic coated pigments useful in the present invention have one of the following formulas: P-[-O-Si-[-(OSiA₂)_0-100-A]₃]_1-100      (3) wherein each of the oxygen atoms at the left end of formula (3) is attached to an atom P in the pigment surface; and each A is an alkyl or alkenyl group having up to 30 carbon atoms. A number of adjacent polysiloxane chains as shown in formula (3) can be cross-linked through oxygen atoms to form a polysiloxane chain with up to 100 repeating -Si(-OP)-O-units that extends along the pigment surface, in addition to the polysiloxane chain which extends away from the pigment surface. Examples of alkyl groups are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and so forth up to octadecyl. "Alkenyl" includes carbon chains with one or more double bonds; examples of such groups include ethylene, propylene, acrylyl, methacrylyl, and residues of unsaturated fatty acids such as oleic (C₁₇H₃₃0-), linoleic (C₁₇H₃₁-), and linolenic (C₁₇H₂₉-).

0009The coated pigments can also exhibit structural formula (4) : P-O-Si(CH₃)₂O)_p-Si(CH₃)₃      (4) wherein p is 1-100, and P is an atom in the pigment surface.

0010The coated pigments can also exhibit structural formula (5): (CH₃)₃SiO-[Si(CH₃)(-OP)-O-Si(CH₃)(-O-P)-O-]_1-50-Si(CH₃)₃      (5) wherein P is an atom in the pigment surface, and in which each of the up to 100 repeating (Si-O) units is bonded through an oxygen atom to the pigment surface.

0011The number of polysiloxane chains of formulas (3), (4), and (5) that are bonded to the pigment surface is not known but is sufficiently high to coat the pigment completely and render it completely hydrophobic. Hydrophobicity can readily be determined by placing the coated pigment into water and observing whether any becomes dispersed or suspended in the water.

0012Suitable pigments include all inorganic and organic pigments or fillers which are usable in cosmetic formulations. Particular examples include talc, mica, titanium dioxide, ferric oxide, ferrous oxide, kaolin, ultramarine, chromium oxide, chormium hydroxide, zinc oxide, silica, manganese violet, and their equivalents. Other examples include lakes of organic colorants such as FD &amp; C Red No. 7 calcium lake, FD &amp; C Yellow No. 5 aluminum lake, D &amp; C Red No. 9 barium lake, and D &amp; C Red No. 30.

0013The pigment (or a mixture of two or more pigments) can be coated by placing it in dry, finely divided form in a mixer and adding a silicone material selected from the group consisting of <ul id="ul0003" list-style="none"><li>(A) A₁SiX₁X₂X₃, wherein A is an alkyl or alkenyl group having 1 to 30 carbon atoms, and X₁, X₂ and X₃ are independently chloro, methoxy, or ethoxy (this material will form coated pigment having formula (3));</li><li>(B) material of the formula (CH₃)₃SiO-(SiCH₃)₂O)_p-Si(CH₃)₂OA₂ wherein p is 1 to 100, and A₂ is hydrogen or an alkyl group having 1 to 30 carbon atoms (this material will form coated pigment having formula (4));</li><li>(C) material of the formula (CH₃)₃SiO(Si(CH₃)(H)-O)_i-Si(CH₃)₃ wherein i is 1 to 100 (this material will form coated pigment having the formula (5)); or a one-phase mixture of two or all three of A, B and C. The relative amounts of fluid: pigment should be sufficient to coat the pigment particles. Generally a fluid: pigment weight ratio is satisfactory for which 1-4 percent of the final product is silicone. The pigment and fluid are intimately mixed thoroughly to obtain a uniform dispersion of the fluid on the pigment, in which the fluid completely coats the particles of pigment. The slurrying operation is advantageously carried out at a temperature of 25°C. to 160°C. effective to promote hydrolysis and reaction of the silicone with the pigment. As an alternative to synthesis, satisfactory coated pigments usable in this invention are commercially available from a variety of sources.</li></ul>

0014The coated pigment compirses about 2 to to about 50 weight percent, and preferably up to about 32 weight pedrcent of the oil phase.

0015The oil phase may also contain optional cosmetically acceptable oil-soluble components, such as preservatives, (e.g., up to 0.5 weight percent of the oil phase of paraben such as propyl paraben); up to 1 percent by weight of the oil phase of any conventional cosmetically acceptable fragrance; and one or more of other components well known to cosmetic chemists, such as those that are intended for cosmetic purposes, for skin-softening and/or for physiological purposes, e.g., for treating skin conditions, like dry skin or chapped skin.

0016Examples of oil-soluble personal skin care components that are useful in the compositions of this invention include, but are not limited to ester waxes, oils and fats of animal or vegetable origin, such as spermaceti wax; beeswax, carnauba wax, lanolin wax, coconut oil, castor oil and lanolin oil; fatty alcohols such as cetyl alcohol, stearyl alcohol and lauryl alcohol; fatty acids such as searic acid and palmitic acid; alkyl esters of fatty acids such as the methyl,ethyl or isoporpyl ester of said fatty acid; hydrocarbon oils and waxes such as mineral oil, petrolatum, perhydrosqualene and paraffin wax; and sunscreens such as octyldimethyl-PABA.

0017The surfactant must be capable of forming a stable water-in-oil emulsion, which means it will exhibit an HLB value of about 2.5 to about 6. The polydiorgano­siloxane segments of the surfactant consist of siloxane units which are interlinked by Si-O-Si linkages and which have the formula R_bSiO_(4-b)/2 The value of b may range from 0 to 3 for said siloxane units with the provision that there is an average of approximately 2, i.e, from 1.9 to 2.1 R radicals for every silicon atom in the copolymer. Suitable siloxane units thus include R₃SiO_1/2, R₂SiO_2/2, RSiO_3/2 and SiO_4/2 siloxane units taken in such molar amounts so that b has an average value of approximately 2 in the copolymer. Said siloxane units may be arranged in linear, cyclic and/or branched fashion.

0018The R radicals of this surfactant may be any radical selected from the group consisting of methyl, ethyl, vinyl, phenyl, and a divalent radical bonding of a polyalkylene segment to the polydiorganosiloxane segment. At least 95 percent of all R radicals are methyl radicals; preferably there is at least one methyl radical bonded to each silicon atom in (d). Divalent R radicals preferably contain no more than 6 carbon atoms. Examples of divalent R radicals include -O-, -C_mH_2mO-, -C_mH_2m- and -C_mH_2mCO₂- wherein m is an integer greater than zero.

0019Illustrative of the siloxane units that make up the polydiorganosiloxane segments of this first surfactant are the following, where Me denotes methyl and Q denotes said divalent R radical together with its bonded polyoxyalkylene segment: R₃SiO_1/2 units such as Me₃SiO_1/2, Me₂(CH₂=CH)SiO_1/2, Me₂(C₆H₅)SiO_1/2, Me (C₆H₅) (CH₂=CH)SiO_1/2, Me₂(CH₃CH₂)SiO_1/2, Me₂QSiO_1/2, MeQ₂SiO_1/2, Q₃SiO_1/2, Q₂(CH₃CH₂)SiO_1/2, and Me(C₆H₅) (Q)SiO_1/2; R₂SiO_2/2 units such as Me₂SiO_2/2, Me(C₆H₅)SiO_2/2, Me(CH₂=CH)SiO_2/2, (C₆H₅)₂SiO_2/2, MeQSiO_2/2, and Q(C₆H₅)SiO_2/2,; RSiO_3/2 units such as MeSiO_3/2, C₆H₅SiO_3/2, CH₂=CHSiO_3/2, CH₃CH₂SiO_3/2 and QSiO_3/2; and SiO_4/2 units.

0020It is to be understood that the silicone-based surfactant may comprise one or more of said polydiorganosiloxane segments. The number of and average molecular weight of the polyorganosiloxane segments in the copolymer is related to the desired weight ratio, hereinafter described, of the polysiloxane and polyalkylene segments in the polymer. Preferably it comprises one polydiorganosiloxane segment having bonded thereto one or more polyoxyalkylene segments.

0021The polyalkylene segments of this surfactant consist of oxyethylene units of the formula -CH₂CH₂O-, alone, or in combination with oxypropylene units of the formula -CH₂CH(CH₃)O-, an average of at least half of the oxyalkylene units in the polyoxyalkylene segments being oxyethylene units. Suitable emulsions of this invention are not formed when the polyoxyalkylene segments contain more than 50 mol percent of the relatively hydrophobic oxypropylene unit. The polyoxyalkylene segments thus correspond to the formula (-CH₂CH₂O-)_p(-CH₂CH(CH₃)O-)_q wherein the oxyalkylene units may be arranged in any suitable fashion such as random, alternating and block. The average values of p and q are such that the value of p is equal to, or greater than, the value of q and the sum of p + q is sufficient to provide an average molecular weight of under 5,000.

0022The polyoxyalkylene segments are bonded to the polydiorganosiloxane segments by at least one terminal portion of said polyoxyalkylene segment, said bonding being by way of a divalent R radical, hereinbefore described. It is to be understood that said bonding may be by both terminal portions of said polyoxyalkylene segment in those copolymers comprising more than one polydiorganosiloxane segments. Any terminal portion of the polyoxyalkylene segment that is not bonded to a polydiorganosiloxane segment is satisfied by a terminating radical. The type of said terminating radical is not critical and may be monovalent, thereby terminating one polyoxyalkylene segment, or polyvalent, thereby terminating more than one polyoxyalkylene segment. Said terminating radicals are made up of atoms selected from the group consisting of carbon, hydrogen, nitrogen and oxygen. Illustrative of said terminating radicals are hydrogen, hydroxyl, alkyl, such as methyl, ethyl, propyl, butyl, benzyl, aryl, such as phenyl; alkoxy such as methoxy, ethoxy, propoxy, butoxy, benzyloxy; aryloxy, such as phenoxy; alkenyloxy, such as vinyloxy and allyloxy; acyloxy, such as phenoxy, alkenyloxy, such as vinyloxy and allyloxy; acyloxy, such as acetoxy, acryloxy and propionoxy and amino such as dimethylamino.

0023Herein "copolymer" means either a block arrangement of segments such as denoted by the formulae (AB)_c, A(BA)_c and B(AB)_c or a pendant arrangement of segments such as (AB_d)_c or combinations thereof wherein A denotes a polydiorganosiloxane segment, B denotes a polyoxyalkylene segment and c and d denotes integers greater than zero and greater than one, respectively. Copolymers (d) may be prepared by modification of the well-known methods described in the polydiorganosiloxane-­polyoxyalkylene copolymer art. The following patents are hereby incorporated herein by reference to show the preparation of polydiorganosiloxane-polyoxyalkylene copolymers: Haluska, U.S. Pat. No. 2,868,824; Haluska, U.S. Pat. No. Re. 25,727; Bailey, U.S. Pat. No. 3,172,899; Pater, U.S. Pat. No. 3,234,252; Simmler, et al. U.S. Pat. No. 3,174,987; Bailey, et al. U.S. Pat. Nos. 3,562,786, 3,600,418 and 3,629,308; Holdstock, U.S. Pat. No. 3,629,165; and Gee, et al. U.S. Pat. No. 4,122,029.

0024It is to be understood that the silicon-bonded reaction groups such as silicon-bonded hydrogen for addition reactions or silicon-bonded hydrolyzable radicals for displacement reactions are preferably completely reacted in the copolymer preparation process, but that trace amounts of said reaction groups may escape reaction with the polyoxyalkylene and may be found in the surfactant.

0025Non-essential components which are common to personal care compositions of the art, such as perfumes, humectants, preservatives, colorants and electrolytes may be incorporated into the compositions of this invention provided they do not destabilize the emulsion so as to cause a breaking or an inverting of the emulsion.

0026The cosmetic composition of the present invention can optionally further comprise a second surfactant which is organic, silicone free, and has an HLB value of 2 to 12, provided that the overall effective HLB value still permits formation of the desired water-in-oil emulsion. The amount should be about 0.25 to 2 weight percent of the composition, and preferably 0.5 to 1 weight percent thereof. As is well known to those of ordinary skill in this art, the HLB value is determined by a standardized technique for measuring the solubility of a surfactant. Said surfactant may be anionic, cationic or non-ionic with respect to its hydrophilic portion. Satisfactory surfactants useful in this invention include polyoxy­alkylene ethers, such as the "Laureth" family of compounds having the general formula CH₃(CH₂)₁₀CH₂(OCH₂CH₂)_nOH in which n has an average value of 3-15 and preferably 5-10. Other examples of suitable surfactants include sodium capryl lactylate and sodium stearoyl lactylte as anionic surfactants, quaternary ammonium chlorides manufactured by Tomah Products, Inc. as Emulsifier Three (™) and Emulsifier Four (™) as coationic surfactants and polyethylene glycol (200) monolaurate, glycerol monolaurate, N,N-dimethylcaproamide, diethylene glycol monolaurate, sorbitan monolaurate and nonylphenoxy polyethoxyethanol as non-ionic surfactants. Other satisfactory silicone-free surfactants include the following: glyceryl monooleate, polyglyceryl-4-decaoleate, PEG-8 Oleate, PEG-4 lauryl ether, PEG-9 lauryl ether and sorbitan sesquioleate. Other examples of suitable organic surfactants having an HLB value of from 2 to 12 may be found by reference to standard publications such as McCutcheon's, Detergents and Emulsifiers, Allred Publishing Company, Ridgewood, New Jersey (1974).

0027The water phase of the composition of the present invention may be simply water, or may contain water-soluble cosmetically acceptable components provided that the emulsion is not destabilized or inverted therein. Examples include humectants, including propylene glycol, glycerine, sodium pyrrolidone carboxylic acids, citric acid, lactic acid and derivatives thereof; preservatives, such as methyl paraben; electrolytes, such as NaCl and magnesium sulfate; and sunscreens such TEA-salicylate or PABA. The water phase comprises up to about 80 weight percent, and preferably up to about 60 weight percent, of the composition, and at least about 15 weight percent of the composition.

0028The composition can also contain effective amounts of optional cosmetically acceptable thickeners or other components such as cellulose derivatives, organically modified clays, and organic thickeners to achieve desired properties such as viscosity, stability and afterfeel. Specific examples of such components are well-known to cosmetic chemists. Some examples are the following: hydroxyethyl cellulose, xathan gum, cationic cellulosic resins, quaternium-18 hectorite, and glyceryl trihydroxy stearate.

0029To make the composition of the present invention, one simply (1) stirs thoroughly together all the components of the oil phase and the surfactant(s), (2) disperses the hydrophobic pigments in the oil phase utilizing a high speed disperser or high shear mill and then (3) stirs in the water phase including any components dissolved in the water phase. Any standard high speed stirring or homogenizing apparatus known to the art can be used to carry out the mixing operation.

0030The invention will be described further in the following examples, which should be interpreted as illustrative rather than limiting.

EXAMPLE 1

0031A cream foundation was made by thoroughly mixing together the following components: <tables id="tabl0001" num="0001"><img file="EP0271925A2_D0001.tif" /></tables> The pigment comprised an intimate blend of the five indicated components, all of which had been thoroughly coated with a polymethyl hydrogen siloxane coating bonded to the pigment surface.

EXAMPLE 2

0032A liquid foundation was prepared by mixing together in the manner indicated above the following components: <tables id="tabl0002" num="0002"><img file="EP0271925A2_D0002.tif" /></tables>

EXAMPLE 3

0033An eyeshadow was prepared by mixing together in the manner indicated above the following components: <tables id="tabl0003" num="0003"><img file="EP0271925A2_D0003.tif" /></tables>

EXAMPLE 4

0034An eyeliner was prepared by mixing together in the manner indicated above the following components: <tables id="tabl0004" num="0004"><img file="EP0271925A2_D0004.tif" /></tables>

EXAMPLE 5

0035A blusher was prepared by mixing together in the manner indicated above the following components: <tables id="tabl0005" num="0005"><img file="EP0271925A2_D0005.tif" /></tables>

EXAMPLE 6

0036A liquid foundation was prepared by mixing together in the manner indicated above the following: <tables id="tabl0006" num="0006"><img file="EP0271925A2_D0006.tif" /></tables>