WO2020153938A1

WO2020153938A1 - Hydrocarbon-containing organopolysiloxane gel

Info

Publication number: WO2020153938A1
Application number: PCT/US2019/014457
Authority: WO
Inventors: Amitabha Mitra; Margaret Whitton; Sienna GERDEMAN
Original assignee: Wacker Chemie Ag
Priority date: 2019-01-22
Filing date: 2019-01-22
Publication date: 2020-07-30

Abstract

High silicone content hydrocarbon-swollen gels are prepared without the use of Si-bonded polyoxyalkylene surfactant groups, without Si-bonded long chain alkyl groups, and without the need for a volatile silicone swelling agent, by hydrosilylatively crosslinking a silicone resin having on average more than two aliphatically unsaturated groups and a non-resinous linear or branched organopolysiloxane having more than two non-terminal Si-H groups, in the presence of a ? C5 hydrocarbon solvent. The gels may be sheared to produce creamy, storage stable gels useful in cosmetics and other applications.

Description

HYDROCARBON-CONTAINING ORGANOPOLYSILOXANE GEL

BACKGROUND OF THE INVENTION

1 Field of the Invention

[0001] The invention pertains to high-solids, hydrocarbon-swollen, cross-linked organopolysiloxane gels. Such gels are very useful in preparing cosmetic compositions, and for other uses as well.

2. Description of the Related Art

[0002] Organopolysiloxanes, sometimes termed“silicones,” have a wide variety of uses in the field of cosmetics and personal care products. For example, silicone oils which contain silicon- bonded phenyl or alkylphenyl groups and have a high refractive index have been touted for addition to haircare products to improve the sheen of hair. Conventional polydimethylsiloxane oils have been added to products such as sunscreen oils and lotions and to other cosmetics of lotion or paste form to improve haptic properties such as smooth skin feel, and also to provide a moisture barrier, since silicones are highly hydrophobic. This same exceptionally hydrophobic property, however, leads to difficulties in formulating products which include silicones. Silicones tend to separate from cosmetic formulations, particularly those which contain considerable amounts of water or low molecular weight polar substances such as lower alcohols, but are also not always compatible with water-free oily compositions either. Thus, in many cases, considerable amounts of emulsifiers have been added to the compositions to disperse the silicones and to prevent phase separation of the composition.

[0003] For some time, the industry has sought methods for incorporating silicones into cosmetic and other formulations, which do not require the use of large amounts, or even any, emulsifiers, and yet which form stable compositions which are not prone to separation into different phases. A potential solution to this long-sought need was through the use of organopolysiloxane gels. In U.S. patent 6,423,322 are disclosed organopolysiloxane gels which are prepared by the hydrosilylative addition reaction of an unsaturated MQ resin with an Si-H-functional organopolysiloxane crosslinker, in the presence of a low viscosity and preferably volatile organopolysiloxane, especially a cyclic organopolysiloxane such as octamethylcyclotetrasiloxane (D4) or decamethylcyclopentasiloxane (D5). These gels are creamy, transparent to opaque products, which are readily incorporated into cosmetic formulations. Unfortunately, the amount of silicone present in these products is limited to relatively small amounts, generally less than 25 weight percent, and the use of low molecular weight, volatile organopolysiloxanes, both linear and cyclic, is now being discouraged. It would be desirable to add greater amounts of organopolysiloxanes to cosmetic products while reducing the amount of silicone gel added.

[0004] In U.S. patent 6,365,670, the problem of the necessary use of an emulsifier

(surfactant) in formulations containing hydrophilic substances to emulsify a silicone gel and avoid phase separation is noted. In the‘670 patent, the solution was to incorporate hydrophilic substances, preferably non-ionic polyoxyethylene hydrophiles, into the silicone gel during its preparation in the presence of an oleaginous composition containing at least 50 weight percent of a low viscosity organopolysiloxane. The presence of polyoxyethylene glycol radicals in the crosslinked silicone decreased the desirable haptic properties of the composition. Moreover, the composition still contained an appreciable amount of volatile silicones, which is undesirable, and also contained “PEG” moieties, which are also now disfavored by the industry.

[0005] In U.S. patent 6,881,416, the desirability of supplying organopolysiloxanes gels to cosmetic formulations without the use of significant quantities of emulsifiers is again noted, and the deficiencies of U.S. 6,365,670 and its inability to incorporate oleaginous substances other than volatile silicones is noted as well. The ‘416 patent teaches to prepare crosslinked organopolysiloxanes which, in addition to containing covalently bonded hydrophilic groups such as those taught by the’670 patent, also include covalently bonded long chain alkyl groups to provide compatibility with non-silicone liquid swellants. The polymerization is conducted in the presence of an oleaginous component which may be free of volatile silicones, but preferably contains up to 50 weight percent of volatile silicones in addition to other oleaginous substances. The silicone gels produced in accordance with the‘416 patent still contain undesirable polyoxyethylene groups and in addition, because of the necessity of also hydrosilylating unsaturated long chain aliphatic hydrocarbons, the preparation process involves several steps and is thus complicated. [0006] It would be desirable to fulfill the long felt need for incorporation of higher quantities of organopolysiloxanes in the form of a creamy, swollen gel while avoiding the necessity of also incorporating polyoxyethylene groups and long chain alkyl groups. It would further be desirable to provide such gels swollen by an oleaginous component which does not require the presence of volatile silicones, and which can be prepared in a simple and cost-effective process, and which has a high silicone content.

SUMMARY OF THE INVENTION

[0007] It is now been surprisingly and unexpectedly discovered that swollen silicone gels having a high cross-linked silicone content, which are swollen by oleaginous substances devoid of volatile silicones, and which do not contain either hydrophilic groups or long chain alkyl groups, can be prepared in a hydrosilylative addition polymerization reaction between an unsaturated organopolysiloxane resin and an Si-H-functional crosslinker bearing Si-H functionality along the polymer backbone of the crosslinker, this reaction taking place in the presence of an oleaginous substance which is preferably a saturated aliphatic hydrocarbon. Despite the absence of hydrophilic groups, the creamy swollen organopolysiloxane gels show excellent compatibility with cosmetic formulations, including those containing appreciable amounts of hydrophilic substances, all without the mandatory use of a surfactant.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIGURE 1 illustrates the improvement in ruboff of a composition employing an inventive gel as compared to the use of a gel derived from a silicone with long chain alkyl groups.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In the field of silicone chemistry, crosslinking, chain extension, and polymer modification through the use of hydrosilylation is well known. In these addition reactions, a moiety containing an Si-H functional group is reacted in the presence of a hydrosilylation catalyst with a moiety containing aliphatic unsaturation. The aliphatic unsaturation may, for example, constitute ethylenic or ethylynic unsaturation, and this unsaturation may be contained within a larger functional group such as a (meth)acrylate group or aliphatically unsaturated ether group, such as an allyl ether group. During the course of the reaction, the Si-H group adds across the aliphatic unsaturated group to produce an Si-C bonded addition product. The Si-H functional moiety and the aliphatically unsaturated moiety may each be monomeric, oligomeric, or polymeric. If the moieties are reacted in a 1 : 1 stoichiometric ratio with respect to Si-H groups and aliphatic unsaturated groups, a simple polymer-analogous addition reaction takes place. If one or both of the reactive moieties is difunctional, then chain extension or polymerization to form linear molecules takes place. However, if one or both of the moieties contain, on average, more than two reactive groups, then a crosslinked product is obtained. In the absence of a solvent, the reaction generally produces silicone oils, modified silicone oils, or silicone elastomers. However, if the reaction includes reactants bearing on average more than two reactive groups, and the reaction takes place in a suitable liquid in which the components or their initial reaction products are to some degree soluble, a solvent-swollen gel may be produced. Since the reaction components are generally stirred during the course of the reaction, the gel is often produced in a“crumbly” form, which can be easily changed to the form of a creamy gel by further agitation, in particular agitation (stirring) under high shear, for example through the use of conventional homogenization equipment, or rotor/stator mixers.

[0010] In the process of forming the inventive gels, a hydrosilylation catalyst (C) is necessary. Hydrosilylation catalysts are well known and widely available from numerous sources. Preferred hydrosilylation catalysts are platinum compounds such as those disclosed in U.S. patents 3,159,601; 3,159,662; 3,220,972; 3,715,334; 3,775,452; 3,814,730, and German published application DE 19536176 Al. Due to the very small quantity of the expensive hydrosilylation catalyst which is required, these catalysts are generally supplied in a solvent or diluent, preferably a solvent suitable for use in cosmetic and pharmaceutical formulations. One preferred catalyst is “Catalyst OL,” a di vinyl -terminated polydimethylsiloxane platinum complex diluted with polydimethylsiloxane, available from Wacker Chemie AG, Munich, Germany. Other platinum catalysts such as the well-known Speier and Karstaedt catalysts, as well as platinum compounds such as hexachloroplatinic acid are also suitable, particularly catalysts which can be supplied in aqueous solution or dissolved or dispersed in a cosmetically suitable liquid such as propanediol. The amount of hydrosilylation catalyst is not overly critical, and amounts from less than one part per million to 1000 ppm, preferably 5 ppm to 200 ppm, and more preferably 10 to 100 ppm, easily determined by one of ordinary skill in the art, calculated as elemental platinum and based on the total amount of Si-H-functional organopolysiloxanes and aliphatically unsaturated organopolysiloxanes, are useful.

[0011] The Si-H-functional organopolysiloxanes are non-resinous, and may be oligomeric or polymeric, and contain hydrogen bonded to silicon along the oligomer or polymer backbone, which may be termed“pendant Si-H”. The Si-H-functional organopolysiloxanes may also contain terminal Si-H groups, but this is not preferred. The Si-H functional organopolysiloxanes are composed of M, D, T, and Q units, more preferably M, D, and T units, yet more preferably M and D units, and also optionally in part, of M and T units. Q units are defined as tetra functional siloxy groups, or S1O4/2 groups. Preferred Si-H-functional organopolysiloxanes are linear organopolysiloxanes composed of D units and two M units as terminal units, and lightly or moderately branched organopolysiloxanes composed of D units, M units as terminal groups, and T and/or Q units which define branching points. M, D, and T units are defined as follows:

M units: R₃S1O_1/2, R_aH_3-aSiOi_/2(“M^H”)

D units: R₂Si0_2/2, RHSi0_2/2, (“D^H”), H₂Si0_2/2

T units: RS1O3/2, HS1O3/2, YS1O2/2

[0012] where R is a C₁-C₂₀ hydrocarbon, for example an alkyl group having 1-20 carbon atoms such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, hexadecyl, and octadecyl; a cycloalkyl group such as cyclopentyl, cyclohexyl, methylcyclohexyl, norbomanyl; or an aromatic, alkaromatic, or arylalkyl group such as phenyl, biphenyl, naphthyl, anthranyl, tolyl, phenyl ethyl, or benzyl preferably a C_1-4 alkyl group, and most preferably the methyl group and

[0013] Y is a siloxy or polysiloxy group preferably comprising D units and an M unit, which may also contain D^H and M^H units, preferably D and/or D^H units and an M unit.

[0014] The number of siloxy units (M, D, T, Q) in the oligomeric Si-H-functional organopolysiloxanes may range from 5 to 10,000, preferably 10-500, and more preferably 40 to 200.

Linear Si-H functional and lightly branched Si-H functional organopolysiloxanes (< 10 mol % T and or Q units, preferably less than 5 mol %) are preferred. Linear Si-H-functional organopolysiloxanes containing substantially only M and D units are most preferred. An example of a suitable Si-H functional organopolysiloxane is a poly(methylhydrogensiloxane/dimethysiloxane) copolymer containing approximately 0.46 wt. % silicon-bonded hydrogen, and containing a total of about 140 D and D^H units and two trimethylsiloxy end units. The Si-H functional organopolysiloxanes are known and are available from numerous sources, or can be synthesized by techniques common in organosilicon chemistry. Such linear and lightly branched organopolysiloxanes are termed“non- resinous” herein, in contrast to the“resinous” silicon resin bearing aliphatically unsaturated groups.

[0015] The aliphatically unsaturated organosilicon resins are silicone resins bearing Si-C bonded functional groups containing ethyl enic or ethylynic unsaturation, i.e. a carbon-carbon multiple bond. Ethylenic unsaturation is preferred, more preferably terminal ethylenic unsaturation such as vinyl, allyl, or 1 -methylvinyl (isopropenyl). Longer chain unsaturated groups such as co- hexenyl are also possible, but not preferred. Also less preferred are unsaturated groups present as (meth)acrylate groups. The vinyl group is most preferred.

[0016] As is well known, the term“silicone resin” is used in the art to refer to very highly branched and crosslinked, network-like organopolysiloxanes containing predominately M, T, and Q units, described below as M', T', and Q units. D' units may also be present, but in amounts of less than 30 mol percent, more preferably less than 15 mol percent, yet more preferably less than 10 mol percent, and most preferably less than 5 mol percent, based on the total mols of T' and Q units. M' units serve as terminal groups, when present. Silicone resins are conveniently categorized by the groups which they contain, and thus may be, inter alia , M'Q resins, T' resins, M'T' resins, M'T'Q resins, M'D'Q resins, etc. Silicone resins cannot be composed of only Q units, nor can they be composed of only D' units or only of M' and D' units. They must contain large amounts of T' and/or Q units. Silicone resins can be liquid or solid, usually solid when D' units are absent or present only in very small amounts, and are generally soluble in aromatic solvents such as toluene, and in some cases aliphatic and cycloaliphatic hydrocarbons.

[0017] In the aliphatically unsaturated silicone resins (B) of the invention, Q has the meaning previously given for the Si-H functional organopolysiloxanes (A), and M', D', and T' have the following meanings: M' units RaR^-aSiOi/i

D units RbR bSiCh/i

T^' units RcRS-cSiCh/i where R is as previously defined,

R¹ is an Si-C bonded functional group containing aliphatic unsaturation, a is 1, 2, or 3, b is 0, 1, or 2, and c is 0 or 1, where at least two R¹ groups are present on average, preferably at least three R¹ groups on average.

[0018] The aliphatically unsaturated silicone resins are preferably M'Q resins, T' resins,

M'T resins, or M'T'Q resins, each of these optionally, but not preferably, containing up to 5 mol percent of D' units. Suitable aliphatically unsaturated silicone resins (B) are available commercially, or can be prepared by standard methods of organosilicon chemistry.

[0019] In both the resinous organopolysiloxane bearing aliphatically unsaturated groups as well as the no-resinous organopolysiloxane bearing Si-H groups, the remaining organo groups which do not themselves participate in the hydrosilylative crosslinking are optionally chlorine or cyano substituted Ci-₄ alkyl groups, preferably methyl or ethyl groups, and most preferably methyl groups. Long chain alkyl groups of 6 carbon atoms or more are preferably absent. However, it would not depart from the spirit of the invention to include an amount of higher alkyl groups which does not impede the storage stability, preferably on average less than 0.5 of such groups per molecule. Higher alkyl groups are preferably absent.

[0020] The hydrocarbon swelling solvent (D) comprises an aliphatic hydrocarbon. The aliphatic hydrocarbon contains at least 5 carbon atoms, preferably at least 8 carbon atoms, and is free of terminal aliphatic unsaturation, and is also free of non-terminal aliphatic unsaturation which is capable of being hydrosilylated during the process of the invention to a degree of more than 10 mol percent based on the total molar content of aliphatic unsaturation in the hydrocarbon swelling solvent. The hydrocarbon swelling solvent is preferably a saturated, aliphatic or cycloaliphatic hydrocarbon. Aromatic hydrocarbons such as toluene and xylene may also be used, but are not preferred. Preferred swelling solvents are linear and/or branched saturated aliphatic hydrocarbons and mixtures thereof, preferably containing Cs-i₈ hydrocarbons.

[0021] The hydrocarbon swelling solvent preferably comprises saturated aliphatic or cycloaliphatic hydrocarbon in an amount of from 30 weight percent to 100 weight percent, based on the total weight of hydrocarbon swelling solvent, preferably 50 to 100 weight percent, more preferably 70 to 100%, yet more preferably 80 to 100%, and most preferably 90-100 weight percent. Most preferably, the hydrocarbon swelling solvent contains 95-100 weight percent of aliphatic or cycloaliphatic hydrocarbons, and especially preferably, 100 weight percent. With particular preference, the hydrocarbon swelling solvent contains 100 weight percent, based on total hydrocarbon swelling solvent, of linear and branched saturated aliphatic hydrocarbons.

[0022] Examples of aliphatic hydrocarbon swelling solvents are pentane, hexane, heptane, octane, decane, dodecane, tetradecane, and octadecane, and their various isomers. Mixtures of such aliphatic hydrocarbons may also be used, and are widely available as fractions having certain boiling ranges. Examples of cycloaliphatic hydrocarbons include cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, and norbornane. More than one type of swelling solvent may be used, for example mixtures of linear and/or branched saturated aliphatic hydrocarbons optionally with saturated cycloaliphatic hydrocarbons and/or aromatic hydrocarbons. The swelling solvent or solvent mixture must be liquid at the hydrosilylative crosslinking reaction temperature, and preferably liquid at 25°C.

[0023] The hydrocarbon swelling solvent may be diluted with up to less than 70 weight percent, based on total swelling solvent, of one or more hydrocarbonoxy liquids. Examples of hydrocarbonoxy liquids are dialkyl ethers such as diethyl ether and di(n-propyl)ether, ketones such as methyl ethylketone and diethyl ketone, cyclic ketones such as cyclopentanone and cyclohexanone; alkyl esters such as ethylacetate, propyl acetate, ethylpropionate, and ethylbutyrate; and especially alcohol and polyol esters, particularly in the form of natural oils such as rapeseed oil, olive oil, palm kernel oil, safflower oil, jojoba oil, sunflower oil, various terpene oils, and the like, and also vitamin oils such as a-tocopherol and vitamin A oil. Most preferably, the hydrocarbonoxy swelling solvents are used in a weight percentage based on the total weight of swelling solvent, of less than 50%, preferably less than 30%, yet more preferably less than 20 weight percent. Most preferably, no hydrocarbonoxy swelling solvents are used.

[0024] Low molecular weight cyclic and linear silicones are preferably absent from the swollen silicone gels, but may be present in small amounts, for example less than 20% by weight, more preferably less than 10% by weight, and most preferably less than 5% by weight. Non volatile, higher molecular weight linear and/or lightly branched liquid silicones may also be present in the same weight proportions, and are also preferably absent. The latter may be used to alter haptic feel or provide hydrophobicity without creating the problems for which low molecular weight volatile linear and cyclic silicones are noted.

[0025] In the preparation of the gel, multiply aliphatically unsaturated hydrocarbons and/or multiply aliphatically unsaturated hydrocarbonoxy compounds may also be used, in conjunction with the aliphatically unsaturated organopolysiloxane resins previously described. Aliphatically unsaturated hydrocarbons contain ethylenic or ethylynic unsaturation, preferably ethylenic unsaturation, as also do the aliphatically unsaturated hydrocarbonoxy compounds. While mono- unsaturated compounds may be used as structure modifiers, which is not preferred, gel formation requires the presence of aliphatically unsaturated hydrocarbons or hydrocarbonoxy compounds containing minimally two aliphatically unsaturated groups.

[0026] Examples of suitable aliphatically unsaturated hydrocarbons with two or more unsaturated groups include butadiene, 1,5-hexadiene, 1,7-octadiene, divinylbenzene, and the like. Examples of suitable aliphatically unsaturated hydrocarbonoxy compounds include the di(meth)acrylates of diols such as ethylene glycol, 1,2-propane diol, 1,3-propane diol, butylene glycol, 1,6-hexanediol, 1,4-cyclohexane diol, and 1,4-cyclohexane dimethanol; di- and tri- (meth)acrylates of polyols such as glycerol, trimethylolpropane, and pentaerythritol; and polyesters containing unsaturated groups derived from maleic acid or anhydride or fumaric acid and other esterifyable unsaturated carboxylic acids. [0027] When used in conjunction with an aliphatically unsaturated organosilicon compound, the amount of aliphatically unsaturated hydrocarbon or hydrocarbonoxy compounds, relative to the total weight of aliphatically unsaturated hydrocarbon or hydrocarbonoxy compound and aliphatically unsaturated organopolysiloxanes, is preferably less than, in order of increasing preference, 40%, 30%, and 20%. Most preferably, the hydrosilylatable compounds present prior to hydrosilylation to form the gel contain no aliphatically unsaturated hydrocarbon or hydrocarbonoxy compounds, or contain less than 10%, more preferably less than 5% on a weight basis relative to the total weight of aliphatically unsaturated hydrocarbon or hydrocarbonoxy compound and aliphatically unsaturated organopolysiloxane. Multiply aliphatically unstaturated hydrocarbon compounds and hydrocarbonoxy compounds are preferably absent.

[0028] Crosslinking of the gel-formers, components (A) and (B), catalyzed by hydrosilylation catalyst (C), must at least partially take place in the presence of the swelling solvent. If the crosslinking is too advanced before addition of the swelling solvent (D), then it will be impossible to stably incorporate the swelling solvent. A two or multi-phase mixture or a mixture which separates into phases over time will be the result. Thus, it is preferable that the swelling solvent (D), or a major portion thereof, is initially present prior to the onset of hydrosilylation. Most preferably, all of the swelling solvent (D) is initially present, and the gel-forming components (A) and (B) are dissolved in the swelling solvent. In a further preferred embodiment, a portion of the swelling solvent is initially present, and the remainder is added subsequently, in one or more increments, or continuously. Thus, most preferably, all components are initially present in solution in the swelling solvent prior to onset of the hydrosilylative crosslinking.

[0029] The reaction is preferably, but not necessarily, conducted under an inert atmosphere such as nitrogen. The reactants and swelling solvent are heated to a temperature at which the hydrosilylation catalyst becomes active and a reasonable reaction time is realized. This temperature can be readily determined by one skilled in the art, and is related to the catalyst activity, its activation temperature, and its concentration. Temperatures of from 10°C to 200°C are useful, but temperatures in the range of 30°C to 150°C are preferred, more preferably 50°C to 120°C, and most preferably 70°C to 90°C. If the reaction temperature is above the boiling point of the swelling solvent, the reaction may be conducted under reflux, or at a pressure higher than atmospheric. This is especially the case where volatile solvents such as pentanes, hexanes, ligroin, or petroleum ether are used as swelling solvents (D).

[0030] The reactor is preferably stirred during the course of the reaction to maintain a homogeneous reaction mixture. The reaction mixture initially becomes viscous, and then gels, the agitation causing the gel to“crumble”, producing a so-called“crumbly gel”. This crumbly gel may be isolated for further processing, or preferably, is converted to a“creamy gel” through intensive agitation, for example, but not limited to, agitation by high shear mixers such as rotor/stator mixers, or by the use of homogenizing devices. The creamy gel thus obtained may have a viscosity ranging from a relatively fluid liquid to a highly viscous liquid, or to a cream or paste. The creamy gel can range from transparent to opaque. The resulting gels are storage stable, meaning that no significant amount of phase separation is visually observable after 1 day of storage at 25°C. Preferably, no phase separation is visually observable after even several weeks of storage at 25°C.

[0031] The relative amounts of the gel-formers (A) and (B) will depend upon the average functionality of these species. In general, silicone gels are only lightly to moderately crosslinked, and thus the sum of the average functionalities with respect to aliphatically unsaturated groups and Si-H groups must be higher than 4, and generally in the range of 5-10. The amounts of the gel formers (A) and (B) by weight can easily be determined by one of ordinary skill in the art. Additional guidance may be provided by U.S. patents, 5,391,592; 5,811,487; 6,365,670; 6,432,322; and 6,881,416, all of which are hereby incorporated by reference, and by the examples presented herein.

[0032] In addition to the necessary ingredients, gel-formers (A) and (B), hydrosilylation catalyst (C), and swelling solvent (D), the reaction mixture may also contain further ingredients (E). Any further ingredients (E) are preferably suitable for use with pharmaceutical and/or cosmetic ingredients. Examples of such further ingredients include, but are not limited to, surfactants, fillers such as reinforcing fillers, an example of which is fumed silica having a BET surface area greater than 50 m²/g, more preferably greater than 100 m²/g, and most preferably in the range of 150-300 m²/g, microbicides, dyes, pigments, UV and thermal stabilizers, UV absorbers, fragrances, and the like. One or more ingredients from each of these general categories may be present, and ingredients from only one of these categories, or from a plurality is categories may also be present. These further ingredients (E) may be added to the necessary reactants (A) through (D) initially, may be added during the course of the hydrosilylation reaction, or may be added following completion of the hydrosilylation reaction. For example, these ingredients may be added to the crumbly gel prior to its further agitation under high shear to produce a creamy gel, or may be added to the creamy gel following its preparation. Further ingredients (E) are preferably absent.

[0033] The gel-forming reaction may optionally be terminated by reducing the temperature of the reaction mixture to a temperature below which the hydrosilylation catalyst is active, but is preferably terminated through the addition of a catalyst poison or inhibitor. Many such catalyst poisons and catalyst inhibitors are known to those skilled in the art. Examples include a variety of phosphorus compounds such as organic phosphines and phosphates, and a variety of sulfur compounds, especially those sulfur compounds containing mercapto groups. An example of such a compound is an organopolysiloxane bearing 3-mercaptopropyl groups in a content of 0.29% by weight, and having a viscosity of 190 mm²/s at 25°C. The amount of catalyst poison or catalyst inhibitor useful is readily determined by one of ordinary skill in the art, and is generally less than 10 weight percent based on the total weight of gel-formers (A) and (B). Preferably, the amount of catalyst poison or catalyst inhibitor is less than 6% by weight on the same basis, more preferably from 0.1 to 5 weight percent, and most preferably from about 0.5 to about four weight percent. These amounts are calculated based on the molecular weight of the 3-mercaptopropyl-functional organopolysiloxanes recited previously, and may be larger or smaller depending upon whether the equivalent weight of the poison/inhibitor is larger or smaller, respectively.

[0034] The gel product contains from 28 to 95 weight % silicone solids and from 72 to 5 wt.

% swelling solvent, based on the sum of silicone solids and swelling solvent, preferably from 30 to 70% silicone solids on the same basis, and more preferably 30% to 50 wt. % silicone solids. If the amount of silicone solids in the gel is less than 28%, separation into multiple phases is observed, or stable gels cannot be formed.

[0035] Examples: A 2000-ml glass reactor is equipped with a condenser, nitrogen inlet, temperature probe, anchor stirrer with wiper attachments, and temperature control system. The reactor is purged with nitrogen, and the reaction is done under continuous nitrogen flow. The solvent isododecane, the SiH-functional crosslinking agent, and the MQ resin are added and stirred at 125 rpm until the resin is dissolved. At this point, the hydrosilylation catalyst is added, and the mixture is stirred for approximately 2 minutes. The reaction mixture is heated in a temperature controlled oil bath at 80° C with a stirring speed of approximately 75 rpm. The liquid mixture starts changing into a gel within 30 minutes. The heating and mixing are continued for two more hours after the onset of gel formation. Then the catalyst inhibitor is added, and the mixture is mixed at 50 rpm for 15 minutes. The heating is removed, and the mixture is cooled to room temperature with stirring at 50 rpm. The mixture is homogenized for 3 minutes at 8000 rpm with an ULTRA- TURRAX^® T 25 homogenizer.

[0036] TABLE 1

*Ratio M/MVi/Q = 7.6/1/11.4, Mn = 2570, MW = 5440, iodine number = 18; **Poly(methylsiloxane - co- dimethylsiloxane) of approximate formula MD_xD^H _yM [0.46 % w/w H content, x+y = 140]

[0037] Formulation Examples

[0038] BB cream formulations were made with the inventive elastomer gel of Example 2

(Formulation 1) and a comparative commercially available elastomer gel BELSIL® RG 90 (INCI: Isododecane and Vinyldimethyl/Trimethylsiloxysilicate Stearyl Dimethicone Crosspolymer, Comprative Formulation C2):

[0039] TABLE 2

[0040] Formulation Procedure:

1) Disperse Carbomer into water 2) Add the rest of Phase A ingredients besides AMP and mix

3) After Phase A is homogenous add AMP, then heat mixture to 75°C with mixing

4) Premix Phase B using a rotor/stator mixer, then heat to 75°C

5) Premix Phase C and heat to 75°C

6) Add Phase C to Phase B and stir, then heat back to 75°C

7) Add Phase B/C to Phase A under high shear, then turn off heat

8) Once cooled to 55°C, add Phase D

9) Add Phase E ingredients separately after temperature is cooled below 40°C

10) Further homogenize using an Ultra Turrax™ mixer

[0041] Visual observation of the BB cream formulations:

Formulation 1 : Smooth texture, thicker

Formulation C2: Grainy texture, thinner

[0042] Measurement of transfer resistance for the BB cream formulations:

[0043] Transfer resistance of the two formulations was measured on film draw downs on aluminum Q-PANEL substrates with a Gardco Washability & Wear Tester Model number D10V.

[0044] Preparation of sample plates:

Clean and label aluminum Q-PANEL substrate plates.

Weigh each plate to 4 decimal places and record.

Use drawdown bar 2” wide to make films of 500 pm thickness.

Measure length of film. Wipe away the excess until the film is 4” long. Prepare three coated plates for each formulation.

Let the plates dry overnight.

Weigh each plate with film to 4 decimal places and record.

Cut 100% Cotton fabric into 6.5”x6.5” rectangles [0045] Testing:

Attach the cotton fabric to the scrubber of the Gardco Washability and Wear Tester and screw in. Clamp aluminum Q-PANEL plate containing sample in front of the scrubber.

Set speed to 3 and turn on machine.

Complete 5 scrubbing cycles.

Remove aluminum Q-PANEL plate.

Repeat procedure for all coated plates.

Weigh plates to 4 decimal and record. Analyze Samples

[0046] The weight % of sample that rubbed off tested area was calculated by using the weight of the aluminum Q-PANEL substrate plates before sample, with sample and after testing. Formulation that showed less amount of material rubbed off are considered to have better transfer resistance.

[0047] The results are presented in Figure 1. It can be seen from the testing that Formulation

C2 containing BELSIL^® RG 90 silicone gel shows 22.8% rub off while Formulation 1 containing the gel of Example 2 shows only 9.7% rub off. Thus, the gel of Example 2 provides much better transfer resistance in a formulation.

[0048] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0049] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.

Claims

WHAT IS CLAIMED IS:

1. A hydrocarbon-swollen, cross-linked organopolysiloxane gel, comprising: a) a hydrocarbon solvent component containing hydrocarbon compounds with more than 5 carbon atoms, in an amount of not more than 72 weight percent, b) a crosslinked organopolysiloxane containing no polyoxyalkylene groups, prepared by hydrosilylative crosslinking of b)i) at least one silicone resin bearing on average per molecule more than two Si-C bonded groups containing aliphatic unsaturation, with

b)ii) at least one non-resinous organopolysiloxane bearing on average per molecule, at least two non-terminal silicon-bonded hydrogen atoms,

wherein the hydrosilylative crosslinking takes place at least in part in the presence of at least a portion of the hydrocarbon solvent component in the presence of a hydrosilylation catalyst, and crosslinked silicone solids (b) formed by the hydrosilylative crosslinking are present in an amount of at least 28 weight percent, the weight percents based on the total weight of (a) and (b), and the gel is stable to phase separation.

2. The hydrocarbon-swollen, crosslinked organopolysiloxane gel of claim 1, wherein the hydrocarbon component comprises aliphatic linear or branched saturated hydrocarbons, saturated cycloaliphatic hydrocarbons, aromatic hydrocarbons, or mixtures thereof.

3. The hydrocarbon-swollen, cross-linked organopolysiloxane gel of claims 1 or 2, wherein the hydrocarbon component contains no more than 10% by weight, based on the total weight of the hydrocarbon component, of one or more volatile cyclic or linear organopolysiloxanes, and preferably contains no volatile cyclic or linear organopolysiloxanes.

4. The hydrocarbon-swollen, cross-linked organopolysiloxane gel of any of claims 1 to 3, wherein neither silicone resin (b)(ii) nor non-resinous organopolysiloxane (b)ii) together contain an amount of silicon-bonded alkyl groups having 6 carbon atoms or more, such that the crosslinked organopolysiloxane (b) contains, on average per molecule, more than 0.5 silicon- bonded alkyl groups having 6 carbon atoms or more.

5. The hydrocarbon-swollen, cross-linked organopolysiloxane gels of any of claims 1 to 4, wherein the organopolysiloxnae gel (b) contains no silicon-bonded alkyl groups having more than 6 carbon atoms.

6. The hydrocarbon-swollen, cross-linked organopolysiloxane of any of claims 1 to 5, wherein all organo groups of the silicone resin (b)(i) other than the aliphatically unsaturated groups, and all organo groups of the non-resinous organopolysiloxane (b)(ii) are Ci-4 alkyl groups, preferably methyl groups.

7. The hydrocarbon-swollen, cross-linked organopolysiloxane of any of claims 1 to 6, wherein the aliphatically unsaturated groups comprise vinyl groups, allyl groups, isopropenyl groups, or (meth)acrylol groups, or mixtures thereof.

8. The hydrocarbon-swollen, cross-linked organopolysiloxane gel of any of claims 1 to 7, wherein the weight percentage of crosslinked organopolysiloxane (b) is in the range of from 30 weight percent to 50 weight percent.

9. The hydrocarbon-swollen, cross-linked organopolysiloxane gel of any of claims 1-8, wherein the hydrocarbon solvent comprises a Cs-is aliphatic linear or branched hydrocarbon, preferably isododecane, or a hydrocarbon mixture containing at least two Cs-is aliphatic linear and branched hydrocarbons.

10. The hydrocarbon-swollen, cross-linked organopolysiloxane gel of any of claims 1-9, wherein all the hydrocarbon solvent is present along with silicone resin (b)(i) and non- resinous organopolysiloxane (b)(ii) prior to initiating crosslinking of (b)(i) with (b)(ii).

11. A process for the manufacture of a hydrocarbon-swollen organopolysiloxane gel of claim 1, comprising:

(a) providing a hydrocarbon solvent;

(b) admixing with the hydrocarbon solvent,

(b)i) a silicone resin bearing on average per molecule more than two Si-C bonded groups containing aliphatic unsaturation; and

(b)ii) a non-resinous organopolysiloxane bearing on average per molecule more than two non-terminal silicon-bonded hydrogen atoms;

(c) prior to or after admixing (b)i) and (b)ii) with (a), adding a hydrosilylation catalyst, and

hydrosilylatively crosslinking silicone resin (b)i) with non-resinous organopolysiloxane (b)ii) until a gel is formed, and (d) optionally adding a catalyst poison to deactivate the hydrosilylation catalyst, wherein the crosslinked organopolysiloxane (b) contains no polyoxyalkylene groups and substantially no long chain C5 or greater alkyl groups.

12. The process of claim 11, wherein the gel is subjected to high shear to form a storage stable creamy gel product.

13. The process of claim 11, wherein the hydrocarbon solvent comprises at least one aliphatic linear or branched hydrocarbon containing 8 to 18 carbon atoms.

14. The process of claim 11, wherein the hydrocarbon-swollen gel contains 30 weight percent or more of crosslinked organopolysiloxane (b) based on the sum of the weights of (a) and (b).

15. A cosmetic formulation, comprising a hydrocarbon-swollen gel of any of claims 1-10 or produced by a process of any of claims 11-14.