United States Patent:  6,037,407

Assignee:  Rhone Poulenc Chimie (Courbevoie, FR)

Filed:  March 19, 1998

A cosmetic composition comprising an aqueous emulsion of organopolysiloxanes selected from the group consisting of silicone oils, gums, resins and mixtures therein which is prepared in a single kneading step which is sufficient to produce an emulsion having a particle size of 0.1 to 5 micrometers is provided.

DETAILED DESCRIPTION OF THE INVENTION

The process for the preparation of emulsions of silicone oils and/or gums and/or resins which forms the subject of the invention is characterized

in that a mixture comprising

100 parts by weight of a silicone phase (A) with a dynamic viscosity at 25^oC. at least equal to 3 Pa.multidot.s, preferably at least equal to 30 Pa.multidot.s, or with a consistency at 25^oC. of less than 2,000, the silicone phase comprising at least one polyorganosiloxane oil and/or gum and/or resin;

2 to 20 parts by weight, preferably from 3 to 15 parts by weight, of water;

3 to 20 parts by weight, preferably from 5 to 15 parts by weight, of at least one surface-active agent (B) or a combination of 0.5 to 10 parts by weight, preferably from 1 to 10 parts by weight, of at least one surface-active agent (B) and of 2.5 x 10-10^-4 to 20 parts by-weight, preferably from 0.001 to 15 parts by weight, of at least one water-soluble thickening polymer (C) with a molecular mass greater than 10,000 g/mol and preferably greater than 100,000 g/mol, is kneaded,

the said surface-active agent or mixture of surface-active agents having an HLB value of at least 10 and the relative amounts of water, constituent(s) (B) and optionally (C) being such that the viscosity or the consistency of the water+surface-active agent(s)+optional water-soluble thickening polymer(s) mixture is in the region of or greater than one-tenth of the viscosity or consistency of the silicone phase (A) and preferably in the region of or greater than the viscosity or consistency of the silicone phase (A); the said kneading being carried out for a period of time and under shearing conditions which are sufficient to produce an emulsion of "oil-in-water" type with a particle size of the order of 0.1 to 5 micrometers and preferably of the order of 0.2 to 3 micrometers;

in that, when a mixture of surface-active agents comprising at least one non-ionic surface-active agent is present, the said mixing is carried out in a single stage;

and then in that the medium is optionally diluted with water according to the desired solids content.

For good implementation of the invention, the dynamic viscosity is preferably measured at 25^oC. using a Brookfield viscometer according to AFNOR standard NFT 76 102 of February 1972; the determination of the consistency can be carried out by measuring the penetrability using a penetrometer, for example according to one of the standards AFNOR NFT 60 119, NFT 60 123, NFT 66 004, ASTM D 217, D 937, D 1321 or D 5.

Mention may be made, as examples of silicone phases (A) which can be used, of those comprising:

a polyorganosiloxane oil and/or gum and/or resin with a viscosity at least equal to 3 Pa.multidot.s, preferably of the order of 30 to 2,500 Pa.multidot.s, or with a consistency of the order of 200 to 2,000.

a mixture of polyorganosiloxane oil(s) and/or gum(s) and/or resin(s), which mixture has a viscosity at least equal to 3 Pa.multidot.s, preferably of the order of 30 to 2,500 Pa.multidot.s, or a consistency of the order of 200 to 2,000.

a mixture of polyorganosiloxane oil(s) and/or gum(s) and/or resin(s) and of at least one solvent of the said oil and/or gum and/or resin and/or of at least one silane and/or of at least one siliceous or non-siliceous filler, which mixture has a viscosity at least equal to 3 Pa.multidot.s, preferably of the order of 30 to 2,500 Pa.multidot.s, or a consistency of the order of 200 to 2,000.

Mention may be made, among the polyorganosiloxane oils and gums which can be used, of those comprising the units of formula

R'₃-a R_a SiO_1/2 and R₂ SiO

in which formulae

a is an integer from 0 to 3

the R radicals are identical or different and represent

a saturated or unsaturated aliphatic hydrocarbon group containing from 1 to 10 carbon atoms;

an aromatic hydrocarbon group containing from 6 to 13 carbon atoms;

a polar organic group bonded to the silicon by an Si--C or Si--O--C bond;

a hydrogen atom;

the R' radicals are identical or different and represent

an OH group

an alkoxy or alkenyloxy group containing from 1 to 10 carbon atoms;

an aryloxy group containing from 6 to 13 carbon atoms;

an acyloxy group containing from 1 to 13 carbon atoms

a ketiminoxy group containing from 1 to 8 carbon atoms

an amino- or amidofunctional group containing from 1 to 6 carbon atoms, bonded to the silicon by an Si--N bond preferably at least 80% of the R radicals of the said oils representing a methyl group.

Mention may be made, among the polyorganosiloxane resins which can be used, of those comprising units of formulae

RSiO_3/2 (T unit) and/or SiO₂ (Q unit)

in combination with units of formula

R'₃-a R_a SiO_1/2 (M unit) and/or R₂ SiO (D unit)

in which formulae a, R and R' have the definition given above.

The latter are generally of the MQ, MDQ, TDM, TD or MT type.

Mention may be made, as examples of aliphatic or aromatic hydrocarbon radicals R, of the following groups:

alkyls, such as for example methyl, ethyl, octyl or trifluoropropyl

alkoxyalkylene, such as for example --CH₂ --CH₂ --O--CH₃ or --CH₂ --CH₂ --O--CH₃,

alkenyls, such as for example vinyl, allyl, hexenyl, decenyl or decadienyl

alkenyloxyalkylene, such as --(CH₂)₃ --O--CH₂ --CH=CH₂ or --(CH₂)₃ --OCH₂ --CH₂ --O--CH=CH₂,

aryls, such as for example phenyl.

Mention may be made, as examples of polar organic groups R, of:

hydroxyfunctional groups such as for example --(CH₂)₃ --OH, --(CH₂)₄ N(CH₂ CH₂ OH)₂ or --(CH₂)₃ --N(CH₂ CH₂ OH)--CH₂ --CH₂ --N(CH₂ CH₂ OH)₂,

aminofunctional groups such as for example --(CH₂)₃ --NH₂ or --(CH₂)₃ --NH--(CH₂)₂ NH₂,

amidofunctional groups such as for example --(CH₂)₃ --N--(COCH₃)--(CH₂)₂ NH(COCH₃),

carboxyfunctional groups such as for example --CH₂ --CH₂ --S--CH₂ --COOH.

Mention may be made, as examples of R' radicals, of the following groups:

alkoxy, such as methoxy, ethoxy, octyloxy, and the like

alkenyloxy, such as vinyloxy, hexenyloxy, isopropenyloxy, and the like

aryloxy, such as phenyloxy, and the like

acyloxy, such as acetoxy, and the like

ketiminoxy, such as ON=C(CH₃)C₂ H₅, and the like

aminofunctional, such as ethylamino, phenylamino, and the like

amidofunctional, such as methylacetamido, and the like.

Mention may be made, as concrete examples of "D units", of:

(CH₃)₂ SiO, CH₃ (CH=CH₂)SiO, CH₃ (C₆ H₅)SiO, (C₆ H₅)₂ SiO, CH₃ HSiO, CH₃ (CH₂ --CH₂ --CH₂ OH)SiO, and the like.

Mention may be made, as concrete examples of "M units", of:

(CH₃)₃ SiO_1/2, (CH₃)₂ (OH)SiO_1/2, (CH₃)₂ (CH=CH₂)SiO_1/2, (CH₃)₂ HSiO_1/2, (OCH₃)₃ SiO_1/2, [O--C(CH₃)=CH₂ ]₃ SiO_1/2, [ON=C(CH₃)]₃ SiO_1/2, (NH--CH₃)₃ SiO_1/2, (NH--CO--CH₃)₃ SiO_1/2, and the like.

Mention may be made, as concrete examples of "T units", of:

CH₃ SiO_3/2, (CH=CH₂)SiO_3/2, HSiO_3/2, and the like.

When the said oils, gums or resins contain reactive and/or polar R radicals (such as H, OH, vinyl, allyl, hexenyl, aminoalkyl, and the like), the latter generally do not represent more than 2% of the weight of the oil or gum and not more than 10% of the weight of the resin.

Viscous polydimethylsiloxane and .alpha.,.omega.-bis(hydroxy)polydimethylsiloxane oils, as well as polydimethylsiloxane, polyphenylmethylsiloxane and .alpha.,.omega.-bis(hydroxy)polydimethylsiloxane gums, are well known commercial products.

Viscous DT polymethylsiloxane resins containing from 1 to 2% by weight of silanol functional groups are also commercial products.

Mention may be made, among the solvents of silicone oils, gums or resins which are optionally present in the silicone phase, of volatile cyclic organopolysiloxanes (octamethylcyclotetrasiloxane, decamethylcyclopentasilbxane, and the like), short polydimethylsiloxane oils (viscosity less than 100 mPa.multidot.s), hexamethyldisiloxane, ketones (methyl ethyl ketone, and the like), ethers (diethyl ether, and the like), esters (isopropylmyristate, ethyl acetate, and the like), some chlorinated or chlorofluorinated solvents (methylene chloride, chloroform, and the like) or highly branched paraffins (white oils based on isoalkanes and cycloalkanes, and the like).

According to the present invention, various inorganic fillers and/or silanes can additionally be present in the silicone phase to be emulsified.

These silanes can especially be by-products from the synthesis of the said polyorganosiloxane oils, gums or resins used or crosslinking agents of the said oils, gums or resins.

They can be represented by the formula (R_b)Si(OR')₄-b, in which formula b is an integer from 0 to 4, R and R' having the definition given above. They are especially described in U.S. Pat. No. 3,294,725, U.S. Pat. No. 4,584,341, U.S. Pat. No. 4,618,642, U.S. Pat. No. 4,608,412, U.S. Pat. No. 4,525,565, EP-A-340,120, EP-A-364,375, FR-A-1,248,826, FR-A-1,423,477 and EP-A-387,157.

Mention may be made, as examples, of the following silanes:

Si(OC₂ H₅)₄, CH₃ Si(OCH₃)₃, CH₃ Si(OC₂ H₅)₃, (C₂ H₅ O)₃ Si(OCH₃), CH₂ =CHSi(OCH₃)₃, CH₃ (CH₂ =CH)Si(OCH₃)₂, CH₂ =CHSi(OC₂ H₅)₃, CH₂ =CHSi[ON=C(CH₃)C₂ H₅ ]₃, CH₃ Si[ON=C(CH₃)₂ ]₃, CH₃ Si[O--C(CH₃)=CH₂ ]₃, methyltris(N-methylacetamido)silane or methyltris(cyclohexylamino)silane.

They are generally present in amounts of the order of 0 to 10 parts by weight, preferably of the order of 0 to 5 parts by weight, per 100 parts by weight of polyorganosiloxane oil(s) and/or gum(s) and/or resin, when they are reaction by-products. When their function as crosslinking agent of hydroxylated oils, gums or resins is sought, they are generally present in amounts of the order of 0.5 to 30 parts by weight, preferably of the order of 2 to 8 parts by weight, per 100 parts by weight of oil(s) and/or gum(s) and/or resin(s).

The said silanes can also be an additive which makes it possible to modulate the physicochemical properties, especially the adhesion properties, of the silicone compositions of various applications obtained from the aqueous emulsions prepared according to the process of the invention. Examples of such silanes are especially described in EP-A-340,120. Mention may be made, from this category of silanes, of for example aminopropyltriethoxysilane, aminopropylmethyl-diethoxysilane or glycidoxypropyltrimethoxysilane. They are used in amounts which can range up to 200%, generally of the order of 2 to 100%, of the weight of oil(s) and/or gum(s) and/or resin(s).

Reinforcing or semi-reinforcing siliceous or non-siliceous fillers may be present according to the invention; mention may be made, as example, of colloidal silicas, precipitated and fumed silica powders, diatomaceous earths, ground quartz, natural calcium carbonate, alumina hydrate, magnesium hydroxide, carbon black, titanium dioxide, aluminium oxide, vermiculite, zinc oxide, mica, talc, iron oxide, barium sulphate or slaked lime; the particle size of these fillers is generally of the order of 0.001 to 300 .mu.m; they are generally present in amounts which can range up to 300%, preferably of the order of 3 to 100%, of the weight of oil(s) and/or gum(s) and/or resin(s).

The surface-active agents (B) used can be non-ionic, with an HLB value greater than 10 and preferably of the order of 10 to 20, anionic, cationic, zwitterionic or amphoteric, with an HLB value greater than 10.

The non-ionic surface-active agents can be chosen from for example alkoxylated fatty acids, polyalkoxylated alkylphenols, polyalkoxylated fatty alcohols, polyalkoxylated or polyglycerolated fatty amides, polyglycerolated alcohols and .alpha.-diols or ethylene oxide-propylene oxide block copolymers, as well as alkylglucosides, alkylpolyglucosides, sugar ethers, sugar esters, sugar glycerides or sorbitan esters, and the ethoxylated compounds of these sugar derivatives, having an HLB value of at least 10.

The anionic surface-active agents can be chosen from for example alkylbenzenesulphonates, alkyl sulphates, alkyl ether sulphates, alkylaryl ether sulphates, dialkyl sulphosuccinates, alkyl phosphates or ether phosphates of alkali metals having an HLB value of at least 10.

Mention may be made, among cationic surface-active agents, of for example aliphatic or aromatic fatty amines, aliphatic fatty amides or quaternary ammonium derivatives having an HLB value of at least 10.

Mention may be made, among zwitterionic or amphoteric surface-active agents, of for example betaines and their derivatives, sultaines and their derivatives, lecithins, imidazoline derivatives, glycinates and their derivatives, amidopropionates or fatty amine oxides having an HLB value of at least 10.

The (mixture of) surface-active agent(s) is chosen as a function of the nature of the polyorganosiloxane oil and/or gum and/or resin; an HLB value of the order of 11 to 15 is generally chosen in order to emulsify a silicone oil or gum (A) comprising an .alpha.,.omega.-bis(trimethyl)polydimethylsiloxane or an .alpha.,.omega.-bis(hydroxy)polydimethylsiloxane; however, ionic surface-active agents with an HLB value greater than 20 are also suitable.

The thickening polymers (C) are soluble to at least 50% in water; mention may be made, as examples of thickening polymers, of

those obtained by chemical synthesis, such as for example poly(vinyl alcohol)s, poly(ethylene glycol)s, polyvinylpyrrolidones or alkali metal polyacrylates,

those extracted from plants and optionally modified, such as for example carrageenans, alginates, carboxymethyl celluloses, methyl celluloses, hydroxypropyl celluloses or hydroxyethyl celluloses,

those obtained by biosynthesis, such as for example xanthan gum.

The relative amounts of water, surface-active agent(s) and optional thickening polymer(s) are functions of the viscosity of the silicone phase comprising at least one polyorganosiloxane oil and/or gum and/or resin, as well as of the nature of the (mixture of) surface-active agent(s) and of the nature of the (mixture of) optional thickening polymer(s). In the absence of thickening polymer, the water/water+surface-active agent(s) ratio by weight is, for example, of the order of 20/100 to 70/100, preferentially of the order 25/100 to 60/100, in order to stabilize an emulsion of a silicone phase comprising an .alpha.,.omega.-bis(trimethyl)- or -(hydroxy)polydimethyl-siloxane oil with a viscosity of the order of 30 Pa.multidot.s to 500 Pa.multidot.s, using a nonylphenol having 9 or 10 ethoxy units as sole surface-active agent. The use of an aqueous phase comprising water and sodium dodecyl sulphate as sole surface-active agent, according to a water/water .dwnarw. surface-active agent ratio by weight of 5/7 and containing from 0.5 to 2% of its weight of hydroxyethyl cellulose as thickening polymer, makes possible the stabilization of .alpha.,.omega.-bis(trimethyl)polydimethylsiloxane oils with a viscosity of the order of 5 Pa.multidot.s to 30 Pa.multidot.s.

The operation of emulsifying the silicone phase can be carried out by

introduction of at least one oil and/or gum and/or resin+optional solvent(s)+optional silane(s) into a water+surface-active agent(s)+optional water-soluble polymer(s) mixture, the optional filler(s) being present in the aqueous mixture and/or introduced into the said mixture, and then kneading at a temperature of the order of 10 to 50 ^oC.;

or preferably introduction of the water into an oil(s) and/or gum(s) and/or resin(s), entirely or partially present [for example, 50-90% of the total amount of oil(s) and/or gum(s) and/or resin(s)],+optional solvent(s)+optional silane(s)+optional filler(s)+surface-active agent(s)+optional water-soluable polymer(s) mixture and then kneading at a temperature of the order of 10 to 50^oC., the optionally remaining amount of oil(s) and/or gum(s) and/or resin(s) being introduced into the medium after the formation of the "oil-in-water" emulsion while continuing to knead.

Any conventional kneading device can be used, especially slow-stirring devices. Thus, the kneading operation can be carried out in a mixer equipped with a stirrer, a stirrer in which the moving part does not rotate at more than 2,500 revolutions/min (preferably at not more than 1500 revolutions/min and very particularly at not more than 500 revolutions/min) with a tangential speed at the end of the moving part not exceeding 20 m/s (preferably not exceeding 5 m/s and very particularly not exceeding 2.5 m/s); advantageously, the tangential speed at the end of the moving part/distance between the end of the moving part and the wall of the mixer ratio is less than 50,000 s^-1, preferably less than 10,000 s^-1 and very particularly less than 2,500 s^-1.

Mention may be made, as examples, of single- or multiple-screw extruders, planetary mixers, hook mixers, slow dispersers, static mixers or paddle, propeller, arm or anchor mixers.

The viscous silicone oil and/or gum and/or resin emulsions obtained according to the process of the invention are particularly stable on storage; they can be very fine and monodisperse; their solids content can range from 25 (or less, depending on the targeted application of the said emulsions) to 98%, it being possible for the solids content to be adjusted by dilution.

They can be used for the preparation of silicone-based compositions which adhere to surfaces made of various materials such as glass, concrete or wood, for the preparation of cosmetic products (shampoos, creams, conditioning agents, liquid soaps or other body hygiene products), of industrial or domestic cleaning products, of domestic descaling products, of surface polishing products (for example for the car) or of polishes (for example for shoes) or for the softening treatment of textiles.

Claim 1 of 1 Claim

1. A cosmetic composition comprising an aqueous emulsion of organopolysiloxane s selected from the group consisting of silicone oils, gums, resins and mixtures thereof, said aqueous emulsion of organopolysiloxanes being prepared by a process consisting essentially of the step of kneading a mixture of (i) 100 parts by weight of a silicone phase having a dynamic viscosity at 25^oC. at least equal to 3 Pa.multidot.s or having a consistency expressed in tenths of a millimeter per minute, as measured by a penetrometer at 25^oC., of less than 2,000, said silicone phase comprising at least one polyorganosiloxane oil, gum, resin or mixture thereof; (ii) 2 to 20 parts by weight of water; and (iii) either 3 to 20 parts by weight of one or more surface-active agents or a combination of 0.5 to 10 parts by weight of at least one surface-active agent and 2.5 x 10^-4 to 20 parts by weight of at least one water-soluble thickening polymer having a mass greater than 10,000 g/mol,

wherein said one or more surface-active agents have an HLB value of at least 10 and the relative amounts of components (ii) and (iii) are such that the viscosity or the consistency of said mixture of components (ii) and (iii) is greater than about one-tenth of the viscosity or consistency of said silicone phase (i); wherein said entire kneading step is carried out for a period of time in a mixer equipped with one or more stirrers in which the moving part of said one or more stirrers does not rotate at more than 500 revolutions/min with a tangential speed at the end of the moving part not exceeding 2.5 m/s so as to produce an oil-in-water emulsion having a particle size of 0.1 to 5 micrometers, and with the proviso that when a mixture of surface-active agents comprising at least one non-ionic surface-active agent is employed, said kneading is carried out in a single step.

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