Silicone elastomer composition and methods for the preparation and use thereof

Abstract

A silicone elastomer composition and methods for preparation and use of said composition are provided. The silicone elastomer composition may be prepared by hydrosilylation reaction of a polyorganohydrogensiloxane and an alpha, omega-diolefin in the presence of a platinum catalyst and 3,3'-oxybis(1,1,1,3,5,5,5-heptamethyltrisiloxane). The resulting silicone elastomer composition is useful in personal care applications.

Description

SILICONE ELASTOMER COMPOSITION AND METHODS FOR THE PREPARA TION AND USE THEREOFCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No.63 / 745,550 filed on January 15, 2025 under 35 U.S.C. §119 (e). U.S. Provisional Patent Application Serial No. 63 / 745,550 is hereby incorporated by reference.FIELD

[0002] This invention relates to a silicone elastomer composition and method for preparation and use of the silicone elastomer composition. More particularly, this invention relates to a silicone elastomer composition including 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane).INTRODUCTION

[0003] US Patent 5654362 and US Patent 5880210, both to Schulz, Jr. et al., disclose silicone elastomers swollen into silicone gels, silicone pastes, or silicone powders. Methods of thickening silicone oils or other solvents to gel-like consistency are provided. Silicone elastomers are prepared by a crosslinking reaction of an =Si-H containing polysiloxane with an alpha, omega-diene in the presence of a platinum catalyst and in the presence of a low molecular weight linear or cyclic polysiloxane. The elastomers can be swollen with the low molecular weight polysiloxane under a shear force.SUMMARY

[0004] A silicone elastomer composition and method for preparing the silicone elastomer composition are provided. The method for preparing the silicone elastomer composition comprises: combining, under conditions to effect hydrosilylation reaction, starting materials comprising a) a polyorganohydrogensiloxane; and b) an alpha, omega-diene; in the presence of starting materials comprising c) a hydrosilylation reaction catalyst, and d) 3,3'-oxybis( 1, 1, 1 ,3,5,5,5-heptamethyltrisiloxane).DETAILED DESCRIPTIONStarting Material a) Polyorganohydrogensiloxane

[0005] In the method for making the silicone elastomer composition introduced above, starting material a) is the polyorganohydrogensiloxane. The polyorganohydrogensiloxane may comprise unit formula (R13SiOi / 2)g(R12HSiOi / 2)h(R12SiO2 / 2)i(R1HSiO2 / 2)j, wherein each R1is an independently selected monovalent hydrocarbyl group of 1 to 20 carbon atoms; and subscripts g, h, i, and j represent average numbers of each unit in the unit formula, and subscripts g, h, i, and j have values such that: 0 < g < 2, 0 <h < 2, a quantity (g + h) = 2, i > 0, j > 0, and a quantity (h +j) > 2. Alternatively, i may be 0 to 250, and j may be 1 to 250.

[0006] Each R1is an independently selected monovalent hydrocarbyl group of 1 to 20 carbon atoms. Examples include alkyl groups and aryl groups, alternatively alkyl groups. Suitable alkyl groups are exemplified by methyl, ethyl, propyl (including n-propyl and isopropyl), butyl (including n-butyl, isobutyl, sec-butyl, and tert-butyl), and branched and linear alkyl groups of 5 to 20 carbon atoms. Suitable aryl groups may have 6 to 20 carbon atoms and may be monocyclic (e.g., phenyl, tolyl, or xylyl) or polycyclic (e.g., naphthyl or anthracenyl); alternatively monocyclic, and alternatively phenyl. Alternatively, each R1may be an alkyl group. Alternatively, each R1may be methyl.

[0007] Alternatively, a) the polyorganohydrogensiloxane may comprises a unit formula selected from the group consisting of al) (R3SiOi / 2)2(R’2SiO2 / 2)a(R”HSiO2 / 2)b, a2) (HR2SiOi / 2)2(R’2SiO2 / 2)c, a3) (HR2SiOi / 2)2(R’2SiO2 / 2)a(R”HSiO2 / 2)b, and a combination of two or more thereof, wherein each R, R’, and R” is an independently selected alkyl group of 1 to 6 carbon atoms (as described above for R1), subscript a is 0 to 250, subscript b is 1 to 250, and subscript c is 0 to 250. Alternatively, the polyorganohydrogensiloxane may comprise unit formula al); and each R, each R’, and each R” may be methyl.

[0008] Suitable polyorganohydrogensiloxanes for use herein are exemplified by:(i) a,co-dimethylhydrogensiloxy-temiinated poly(dimethylsiloxane / methylhydrogensiloxane), (ii) a.o)-dimethylhydrogensiloxy-terminated polymethylhydrogensiloxane,(iii) a,co-trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane),(iv) a,co-trimethylsiloxy-terminated polymethylhydrogensiloxane, and(v) a-dimethylhydrogensiloxy-o-trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane),(vi) a-dimethylhydrogensiloxy-co-trimethylsiloxy -terminated polymethylhydrogensiloxane, (vii) a combination of two or more thereof.

[0009] Polyorganohydrogensiloxanes are also commercially available, such as those available from Gelest, Inc. of Morrisville, Pennsylvania, USA, for example, HMS-H271, HMS-071, HMS-993; HMS-301 and HMS-301 R, HMS-031, HMS-991, HMS-992, HMS-993, HMS-082, HMS-151, HMS-013, HMS-053, HAM-301, and HMS-HM271. Methods of preparing linear and branched polyorganohydrogensiloxanes suitable for use herein, such as hydrolysis and condensation of organohalosilanes, are well known in the art, as exemplified in US Patent 2823218 to Speier; US Patent 3957713 to Jeram, et al.; and US Patent 4329273 to Hardman, et al.

[0010] The amount of starting material a) is not specifically restricted and may depend on various factors including the content of silicon bonded hydrogen atoms (SiH content) of startingmaterial a), the presence or absence of any optional additional starting materials, the species of catalyst selected, and the reaction conditions. However, the amount of starting material a) may be 11 weight % to 16 weight %, based on combined weights of starting materials a), b) and d) described herein. Alternatively, it may be desirable to minimize or eliminate potential for unreacted silicon bonded hydrogen atoms in the silicone elastomer composition to be produced, therefore, starting material a) and starting material b) (and any optional additional starting materials) may be present in amounts sufficient to provide a molar ratio of silicon bonded hydrogen atoms to alkenyl groups (the SiH:Vi ratio) of 10:1 to 1:10, alternatively 5:1 to 1:5, alternatively 2:1 to 1:2, alternatively 1:1, and alternatively <1:1. Alternatively, a molar excess of aliphatic unsaturation from may be utilized as compared to the SiH content to minimize or eliminate unreacted SiH in the silicone elastomer composition, such that SiH: Vi ratio is <1:1, alternatively 1:1 to <1:1.Starting Material b) Alpha, Omega-Diene

[0011] Starting material b) is an alpha, omega-diene. The alpha, omega-diene may have formula CH2=CH-R2-CH=CH2, wherein R2is a divalent hydrocarbyl group of 1 to 20 carbon atoms, alternatively 2 to 14 carbon atoms, alternatively 2 to 10 carbon atoms, and alternatively 4 to 8 carbon atoms. Alternatively, R2may be an alkane-di-yl group, such as a linear alkane -di-yl group. Examples of starting material b) include 1,4-pentadiene (CAS #591-93-5); 1,5-hexadiene (CAS #592-42-7); 1,6-heptadiene (CAS #3070-53-9); 1,7-octadiene (CAS #3710-30-3); 1,8-nonadiene (CAS #4900-30-5); 1,9-decadiene (CAS #1647-16-1); 1,11 -dodecadiene (CAS #5876-87-9); 1,13 -tetradecadiene (CAS #21964-49-8) and combinations thereof. Alternatively, starting material b) may be selected from the group consisting of 1,4-pentadiene; 1,5-hexadiene; 1,6-heptadiene; and combinations thereof. Suitable alpha, omega-dienes are known in the art and are commercially available from various sources including Sigma-Aldrich, Inc. of St. Louis, Missouri, USA; Fisher Scientific of Ontario, Canada; and TCI America of Portland, Oregon, USA. Starting material b) may be used in an amount as described above or below.Alternatively, starting material b) may be used in an amount of 0.4% to 0.6%, based on combined weights of starting materials a), b) and d).Starting Material c) Hydrosilylation Reaction Catalyst

[0012] Starting material c) is a hydrosilylation reaction catalyst. This catalyst will promote a reaction between the alkenyl groups in starting material b) and the silicon bonded hydrogen atoms in starting material a). Said catalyst comprises a platinum group metal. The platinum group metal may be selected from the group consisting of platinum, rhodium, ruthenium, palladium, osmium, and iridium. Alternatively, the platinum group metal may be platinum. The hydrosilylation reaction catalyst may be the platinum group metal, described above; a compoundof such a metal, for example, chlorotris(triphenylphosphine)rhodium(I) (Wilkinson’s Catalyst), a rhodium diphosphine chelate such as [l,2-bis(diphenylphosphino)ethane]dichlorodirhodium or [l,2-bis(diethylphospino)ethane]dichlorodirhodium, chloroplatinic acid (Speier’s Catalyst), chloroplatinic acid hexahydrate, or platinum di chloride; a complex of a compound such as 1,3-diethenyl-l,l,3,3-tetramethyldisiloxane complexes with platinum (Karstedt’s Catalyst) and Pt(O) complex in tetramethyltetravinylcyclotetrasiloxane (Ashby’s Catalyst); or a platinum group metal compound microencapsulated in a matrix or coreshell type structure. Alternatively, c) the hydrosilylation reaction catalyst may be selected from the group consisting of chloroplatinic acid, chloroplatinic acid hexahydrate, and Karstedt’s catalyst. Hydrosilylation reaction catalysts are known in the art, see for example, US Patent Application Publication 20240026084 and the references cited therein. Suitable hydrosilylation reaction catalysts for use herein are commercially available, for example, SYL-OFF™ 4000 Catalyst and SYL-OFF™ 2700 are available from Dow Silicones Corporation of Midland, Michigan, USA. The amount of the hydrosilylation reaction catalyst depends on various factors including the species of catalyst selected, the SiH content of starting material a) and the process conditions selected. However, the amount of hydrosilylation reaction catalyst may be sufficient to provide 1 ppm to 6000 ppm of the platinum group metal based on combined weights of starting materials a), b) and d). Alternatively, the amount of said catalyst may be 0.00001 to 0.5 parts by weight, per 100 parts by weight of the polyorganohydrogensiloxane; alternatively 0.00001 to 0.02 parts, and alternatively 0.00001 to 0.002 parts by weight, per 100 parts by weight of a) the polyorganohydrogensiloxane.Starting Material d) M2TTM2

[0013] Starting material d) used in the method for making the silicone elastomer composition is 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane), which has formula

[0014] The M2TTM2 used herein may be prepared by various methods. For example, a method for preparing a product comprising 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) is provided herein. The method may comprise: 1) mixing A) 1,1,1,3,5,5,5-heptamethyltrisiloxane and C) tris(pentafluorophenyl)borane, wherein C) the tris(pentafluorophenyl)borane is used in an amount sufficient to provide 50 ppm by weight to 200 ppm by weight based on A) the 1,1,1,3,5,5,5-heptamethyltrisiloxane, thereby preparing a first mixture; 2) mixing B) trimethyl orthoformate and additional C) tris(pentafluorophenyl)borane, wherein the additional tris(pentafluorophenyl)borane is used in an amount sufficient to provide 100 ppm by weight to 300 ppm by weight based on B) the trimethyl orthoformate, thereby preparing a second mixture: and 3) feeding the second mixture into the first mixture under conditions to control temperature at 10 °C to 30 °C, thereby forming the product comprising 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane). The method may optionally further comprise one or more additional steps. For example, the method may further comprise step 4): mixing the product at 23 °C ± 3 °C for at least 1 hour. Without wishing to be bound by theory, it is thought that step 4) may allow for increasing yield, if unreacted starting materials are present after step 3). The method may optionally further comprise step 5): purifying the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane). Step 5) may be performed after step 3) or after step 4), when step 4) is present.

[0015] The 1,1,1,3,5,5,5-heptamethyltrisiloxane used in the method has formula:commercially available from various sources such as Sigma- Aldrich, Inc. of St. Louis, Missouri, USA; TCI America division of Tokyo Chemical Industry, of Portland, Oregon, USA; Oakwood Chemical of West Columbia, South Carolina, USA; and Fisher Scientific of Waltham, Massachusetts, USA.

[0016] The trimethyl orthoformate used in the method has formula:Trimethyl orthoformate is commercially available from various sources including Sigma-Aldrich, Inc. and Fisher Scientific.

[0017] The tris(pentafluorophenyl)borane used in the method has formulaTris(pentafluorophenyl)borane is commercially available from various sources, such as Sigma-Aldrich, Inc., TCI America, and Fisher Scientific. Tris(pentafluorophenyl)borane may be prepared by known methods, such as those disclosed in US Patent US5744646.

[0018] These starting materials used in the method for preparing M2TTM2 may be combined by mixing in a reactor with heating and cooling means, such as a jacket, and mixing means such as an agitator, baffles, or both. An inert gas, such as nitrogen or argon, may be used to reduce oxygen content in the reactor. The tris(pentafluorophenyl)borane may be dissolved in a solvent (e.g., an aromatic hydrocarbon such as benzene, toluene, or xylene) to aid mixing and delivery. Alternatively, the 1,1,1,3,5,5,5-heptamethyltrisiloxane; tris(pentafhiorophenyl)borane; and the solvent may be combined in the reactor to form the first mixture.

[0019] The second mixture comprising the trimethyl orthoformate and the additional tris(pentafluorophenyl)borane (and optionally a solvent) may be added to the first mixture continuously or in aliquots. For example, the second mixture may be added over 50 minutes to 90 minutes, alternatively 70 minutes. The second mixture may be added to the first mixture with heating or cooling, e.g., at a temperature of 10 °C to 30 °C.

[0020] The method for preparing M2TTM2 described herein may optionally further comprise one or more additional steps as described above. Step 5) purifying the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) may comprise neutralizing the catalyst by adding a neutralizing agent for the tris(pentafluorophenyl)borane catalyst after preparing the product comprising 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane). Purifying may comprise filtration to remove the neutralizing agent, when used. Any suitable neutralizing agent may be used. Suitable neutralizing agents for tris(pentafluorophenyl)borane catalyst, such as metal oxides orhydroxides (e.g., neutral alumina). Alternatively, purifying may comprise removing an unreacted starting material, a side product, and / or solvent, when used, such as by stripping, distillation, or evaporation. The resulting product comprises 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) with good yield and purity.

[0021] Alternatively, the method for preparing M2TTM2 may comprise: optionally 1) preparing 1, 1,1, 3, 5, 5, 5-heptamethyltrisiloxan-3-ol by a method comprising: 1) combining, under conditions to effect hydrolysis reaction, starting materials comprising 1,1, 1,3, 5, 5, 5-heptamethyltrisiloxane, water, a metal catalyst capable of catalyzing the hydrolysis reaction, optionally a solvent, and optionally a buffer, thereby forming an intermediate comprising the 1.1.1.3.5.5.5-heptamethyltrisiloxan-3-ol and a side product comprising water; optionally 2) purifying the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol; 3) combining, under conditions to effect dehydration reaction, starting materials comprising l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol; 1.1.1.3.5.5.5-heptamethyltrisiloxane; and tris (pentafluorophenyl)borane, thereby preparing the product comprising 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane); and optionally 4) purifying the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane).

[0022] In this method for preparing M2TTM2, l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol hasformulaThe 1,1, 1,3, 5, 5, 5-heptamethyltrisiloxan-3-ol may be prepared as described herein, or may be purchased. For example, l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol is commercially available, for example, from Bench Chem of Pasadena, California, USA. The amounts of 1, 1,1, 3, 5,5,5-heptamethyltrisiloxan-3-ol and 1,1,1,3,5,5,5-heptamethyltrisiloxane are not specifically restricted, however, they may be used in a molar ratio of 1 : 1 , alternatively 1.1 : 1 to 1 : 1.1 such that the amount of unreacted starting material may be minimized.

[0023] When the method includes preparing heptamethyltrisiloxan-3-ol, the hexamethyldisiloxane used is as described above. The water is not specifically restricted. The water is not generally limited, and may be utilized neat (i.e., absent any carrier vehicles and / or solvents), and / or pure (i.e., free from, or substantially free from, minerals and / or other impurities). For example, the water may be processed or unprocessed prior to the reaction with 1.1.1.3.5.5.5-heptamethyltrisiloxane. Examples of processes that may be used for purifying the water include distilling, filtering, deionizing, reverse osmosis and combinations of two or more thereof. Alternatively, the water may be unprocessed (e.g. may be tap water, i.e., provided by a municipal water system or well water, used without further purification). Alternatively, the water may be purified before reaction with 1,1,1,3,5,5,5-heptamethyltrisiloxane. Alternatively, thewater may be utilized as a mixture (e.g. solution or suspension) comprising a carrier vehicle and / or solvent. The water may be utilized in any amount, which will be selected by one of skill in the art, depending on various factors, e.g., the particular palladium catalyst selected, the reaction parameters employed, the scale of the reaction (e.g. total amount of 1, 1,1, 3, 5,5,5-heptamethyltrisiloxane to be converted).

[0024] The catalyst may be a heterogeneous catalyst comprising palladium or platinum on a support, such as carbon. Alternatively, the catalyst may be a palladium catalyst. Suitable catalysts are known in the art and are commercially available, e.g., from Sigma-Aldrich, Inc. of St. Louis, Missouri, USA. The amount of catalyst depends on various factors including the conditions selected for the reaction and whether a platinum or palladium catalyst will be used, however the amount may be sufficient to provide at least 10 ppm of metal based combined weights of the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol and 1,1,1,3,5,5,5-heptamethyltrisiloxane, alternatively at least 50 ppm; while at the same time the amount may be up to 500 ppm, alternatively up to 150 ppm, on the same basis. Alternatively, the amount of catalyst may be 10 ppm to 500 ppm, alternatively 50 ppm to 150 ppm, on the same basis.

[0025] The solvent is optional. The solvent is not specifically restricted and is exemplified by a ketone such as acetone, or tetrahydrofuran. The solvent may facilitate mixing of the 1,1,1,3,5,5,5-heptamethyltrisiloxane and the water.

[0026] The buffer may optionally be used in step / ) of the method described herein to neutralize the starting materials used to prepare the l,l,l,3,3,5,5,5-heptamethyltrisiloxan-3-ol. The buffer may be a neutral phosphate buffer. For example, 1% to 10% phosphates in water as a buffer solution may be used. Step 1) of the method described herein may comprise combining, e.g., by mixing, the buffer, the solvent, and the palladium catalyst to form a first mixture; and adding the 1,1,1,3,5,5,5-heptamethyltrisiloxane to the first mixture continuously or in aliquots. For example, the 1,1,1,3,5,5,5-heptamethyltrisiloxane may be added to the first mixture over a time period of 80 minutes to 120 minutes. These starting materials may be combined in a reactor with cooling and / or heating means, such as a jacket. Step 1) may be performed at a temperature of 10 °C to 30 °C. Optionally, step 1) may further comprise mixing the reactor contents after completion of the addition of 1,1,1,3,5,5,5-heptamethyltrisiloxane for a period of time to allow for completion of reaction, e.g., 5 minutes to 8 hours, alternatively 2 to 6 hours, and alternatively 4 hours.

[0027] When step 2) purifying the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol is present, step 2) may comprise removing the catalyst, removing the solvent, removing the side product, or a combination thereof. Removing the catalyst may be performed by any convenient means such as filtration, e.g., when a heterogeneous catalyst is used. Removing the solvent and / or the sideproduct may be performed by any convenient means such as stripping, distillation, and / or evaporation (e.g., with a rotary evaporator), optionally with reduced pressure.

[0028] In this method described above for preparing the M2TTM2, starting materials comprising the 1 , 1 , 1 ,3,5,5,5-heptamethyltrisiloxan-3-ol; 1,1,1 ,3,5,5,5-heptamethyltrisiloxane; and tris(pentafluorophenyl)borane (as described above) may be combined under conditions to effect dehydration reaction, thereby preparing the product comprising 3,3'-oxybis(l ,1 ,1 , 3, 5,5,5-heptamethyltrisiloxane). An additional solvent may optionally be used in this step, e.g., to facilitate mixing of the tris(pentafluorophenyl)borane and the other starting materials. The additional solvent may be an aromatic hydrocarbon, such as benzene, toluene, xylene, or a combination thereof; alternatively toluene. For example, step 3) may be performed by a technique comprising: optionally, i) dissolving the tris(pentafluorophenyl)borane catalyst in a solvent to form a catalyst solution, ii) mixing starting materials comprising 1, 1,1, 3, 5,5,5-heptamethyltrisiloxane and the tris(pentafluorophenyl)borane catalyst, thereby preparing a second mixture, and iii) adding l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol to the second mixture.

[0029] These starting materials used in the dehydration reaction step in the method for preparing M2TTM2 may be combined by mixing in a reactor with heating means, such as a jacket. An inert gas, such as nitrogen or argon, may be used to reduce oxygen content in the reactor. Alternatively, the 1,1,1,3,5,5,5-heptamethyltrisiloxane; tris(pentafluorophenyl)borane; and the additional solvent may be combined in the reactor to form a second mixture. The l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol may be added to the second mixture continuously or in aliquots. For example, the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol may be added over 60 minutes to 100 minutes, alternatively 80 minutes. The l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol may be added to the second mixture with heating, e.g., at a temperature of 60 °C to 65 °C. Optionally, additional catalyst, or additional catalyst solution, may be added during step iii) from one to three times.

[0030] This method for preparing M2TTM2 described herein may optionally further comprise one or more additional steps. The additional step may comprise neutralizing the catalyst by adding a neutralizing agent for the tris(pentafluorophenyl)borane catalyst after preparing the product comprising 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane). The additional step may comprise purifying the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane). Purifying may comprise filtration to remove the neutralizing agent, when used. Alternatively, purifying may comprise removing an unreacted starting material, a side product, and / or solvent, when used, such as by stripping, distillation, or evaporation. The resulting product comprises 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) with good yield and purity. The 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) is used in the method for preparing the siliconeelastomer composition. Starting material d), the 3,3'-oxybis( 1, 1 ,1 , 3, 5,5,5-heptamethyltrisiloxane) may be used in an amount of 67% to 82%, based on combined weights of starting materials a), b), and d) described above when preparing the silicone elastomer composition.Method for Preparing Silicone Elastomer Composition

[0031] The method for preparing the silicone elastomer composition comprises: (T) combining, under conditions to effect hydrosilylation reaction, starting materials comprising: a) the polyorganohydrogensiloxane; and b) the alpha, omega-diene; in the presence of starting materials comprising c) the hydrosilylation reaction catalyst; and d) the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane), each as described above.

[0032] An additional starting material may optionally be used in the method for making the silicone elastomer composition described herein. For example, e) an alpha-olefin may be added in addition to the starting materials a) polyorganohydrogensiloxane, b) alpha, omega-diene, c) hydrosilylation reaction catalyst, and d) M2TTM2, described above. The alpha-olefin may have formula CH2=CR3-R4, wherein R3is hydrogen or an alkyl group of 1 to 40 carbon atoms, and R4is an alkyl group of 1 to 40 carbon atoms. Alternatively, R3may be H or methyl. Alternatively R3may be H. Alternatively, R4may have 1 to 30 carbon atoms, alternatively 1 to 20 carbon atoms. Examples of suitable alpha-olefins include propylene (CAS #115-07-1), 1 -butene (CAS #106-98-9), isobutylene (with CAS #115-11-7, also named 2-methylpropene), 1-pentene (CAS #109-67-1), 2-methyl-l-butene (CAS #563-46-2), 3-methyl-l-butene (CAS #563-45-1), 1-hexene (CAS #592-41-6), 2-methyl-l-pentene, 3-methyl-l-pentene, 4-methyl-l-pentene, 1-heptene, 2-methyl-l-hexene, 1 -octene (CAS #111-66-0), 2-methyl-l-heptene, 1 -nonene, 1 -decene (CAS #872-05-9), 1-undecene, 1-dodecene (CAS #112-41-4), 1-tridecene, 1-tetradecene (CAS #1120-36-1), 1 -pentadecene (CAS #13360-61-7), 1-hexadecene (CAS #629-73-2), 1 -heptadecene (CAS #6765-39-5), 1-octadecene (CAS #112-88-9), 1-nonadecene (CAS #629-92-5), 1-eicosene (CAS #3452-07-1), 1-hexacosene, 1-octacosene, and combinations thereof. Suitable alpha-olefins are known in the art and are commercially available from various sources including Sigma- Aldrich, Inc. and Chevron Phillips Chemical of The Woodlands, Texas, USA (under the tradename AlphaPlus™). The alpha-olefin is optional, so its amount may be 0. Alternatively, the polyorganohydrogensiloxane and the combined amounts of the alpha, omega-diene and the alpha-olefin are sufficient to provide SiH:Vi ratio of 1:1 to < 1:1.

[0033] Step (I) may be performed at RT. Alternatively, step (I) may be performed with heating to increase reaction rate (e.g., reduce time to produce the silicone elastomer composition). For example, step (I) may be performed at a temperature of 60 °C to 90 °C for 8 minutes to 5 hours. Step (I) may be performed under a shear force. Any type of mixing andshearing equipment may be used, for example a batch mixer, planetary mixer, single or multiple screw extruder, dynamic or static mixer, colloid mill, homogenizer, sonolator, or a combination thereof. The starting materials may be combined in any suitable order. One skilled in the art would recognize that it would be undesirable from a safety perspective to combine a) the polyorganohydrogensiloxane and c) the hydrosilylation reaction catalyst without the b) the alpha, omega-diene or e) the alpha-olefin, when used.

[0034] The silicone elastomer composition may comprise 65% to 98% of the M2TTM2 with the balance being the silicone elastomer prepared via the hydrosilylation reaction. Alternatively, the silicone elastomer composition may comprise 70% to 98% of the M2TTM2.

[0035] The method may optionally further comprise one or more additional steps. For example, all or a portion of the M2TTM2 may be used in step (I). When only a portion is used, the method may further comprise (II) adding additional M2TTM2 to the product of step (I), optionally with mixing under shear.

[0036] Alternatively, when e) the alpha-olefin is used, the method may further comprise step pre-(I): combining a) the polyorganohydrogensiloxane and e) the alpha-olefin in the presence of c) the hydrosilylation reaction catalyst form a polyorganohydrogensiloxane grafted with alkyl groups (derived from the alpha-olefin), and thereafter, combining the polyorganohydrogensiloxane grafted with alkyl groups with the other starting materials as described above in step (I). Alternatively, the reaction may be performed in one step by combining a mixture of the polyorganohydrogensiloxane, the alpha-omega diene, the alphaolefin, the M2TTM2, and the platinum catalyst.Method of Use

[0037] Silicone elastomer compositions containing 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltri siloxane) may be prepared via in the method described in US Patent 5654362 and US Patent 5880210, both to Schulz, Jr. et al. by replacing all, or a portion, of the low molecular weight linear or cyclic polysiloxanes disclosed therein with 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane). The silicone elastomer compositions prepared as described herein may be used in various end use applications, e.g., personal care applications such as antiperspirants, cosmetics, deodorants, and skin care compositions. Without wishing to be bound by theory, it is thought that the use of 3,3'-oxybis(l,l,l,3.5,5,5-heptamethyltrisiloxane) described herein provides the benefit of minimizing or avoiding the use of cyclic polydiorganosiloxanes, and / or other polydiorganosiloxanes that can form cyclic polydiorganosiloxanes during preparation, storage, and / or use of the silicone elastomer compositions and products made with them.EXAMPLES

[0038] The following examples are provided to illustrate the invention to one skilled in the artand are not to be construed so as to limit the scope of the invention set forth in the claims. The starting materials used in this invention are summarized below in Table 1.Table 1 - Starting Materials

[0039] In this Synthesis Example 1, 0.76g TMOF was added into a 1 / 2-oz. vial and stirred at ~20 °C. 39 pl of BCF / toluene solution (4.825%) was added into the vial (to make a solution containing BCF at 300 ppm). 4.79 g of MD M was added into the vial slowly (over 10 minutes). A molar ratio TMOF / MD M = 1 / 3. The vial was not capped but covered with Al foil to minimize moisture exposure. No sign of reaction was observed for 7 hours (no gas generation and no exotherm). Stirring was continued at ~20 °C for a total of 48 hours. 20 mg of triphenylamine was added to quench the BCF catalyst. GC-FID results showed MD M converted to 3-methoxy-l,l,l,3,5,5,5-heptamethyltrisiloxane (MDOMeM) and M2TTM2 at -60 / 40 GC peak area ratio. Formation of M2TTM2 generated CH4 gas and heat. It was unknown when the conversion to M2TTM2 happened after the initial 7 hours where no sign of reaction was observed. With this order of addition of the starting materials, commercial scale production would be impractical due to long batch time, and the resulting yield and purity were both undesirably low.

[0040] In this Synthesis Example 2, reaction of DME with MD’M was performed as follows: 10.0 g MD’M was charged into a 1-oz. vial. With stirring at -20 °C, 80 pl of BCF catalyst solution (4.825% BCF in toluene) was added into the vial, with a target of 300 ppm BCF. DMEwas added into the vial dropwise. No sign of reaction (no exotherm and no gas generation) was observed. Another 80 pl of BCF catalyst solution (4.825% in toluene) was added into the vial so that BCF totaled 600 ppm. The reaction was very slow at ~20 °C.

[0041] The vial was heated to 60 °C on a hotplate, and fast reaction was observed fast reaction.DME addition continued drop wise to a total of 1.01 g within ~3 minutes. Stirring continued at 60 °C for 2 hours until no more gas bubble generation was observed. The vial was then cooled to ~20 °C.

[0042] In this Synthesis Example 3, reaction of Diethylene glycol methyl ethyl ether with MD’M was performed as follows: 10.0 g MD’M was charged into a 1-oz. vial. With stirring at ~20 °C, 80 pl of BCF catalyst solution (4.825% BCF in toluene) was added into the vial, with a target 300 ppm BCF. DEGME was added into the vial dropwise. No sign of reaction (no exotherm and no gas generation) was observed. Another 80 pl of BCF catalyst solution (4.825% in toluene) was added into the vial so that BCF totaled 600 ppm. No reaction was observed at ~20 °C.

[0043] The vial was heated to 60 °C on a hotplate, and fast reaction was observed. The addition of Diethylene glycol methyl ethyl ether continued to a total of 1.08 g drop wise within ~3 minutes. Stirring continued at 60 °C for 2 hours. No more gas bubble generation was observed, and the vial was cooled to ~20 °C.

[0044] In this Synthesis Example 4, the procedure of Liao, Brook, et al. “Living synthesis of silicone polymers controlled by humidity’-, European Polymer Journal, Volumel07, Pages 287-293 was performed. Yield was only 50 %, and purity by GC-FID was 95 area %. Comparative Example 4 showed that the reaction was difficult to control, and without wishing to be bound by theory it is thought that water deactivated the catalyst. The yield reported by Brook et al. was not achievable by practicing the process as described in the reference.

[0045] In this Synthesis Example 5, 87.7 g neutral phosphate buffer, 616.5 g of acetone, and 5.8 g of Pd / C catalyst (1% Pd) were mixed in a 2000 ml flask equipped with a mechanical stirrer, a thermal couple, and an adapter to a N2 bubbler. Under vigorous stirring, 541g of MD’M was added into the flask slowly in 100 minutes via a peristaltic pump. Temperature was maintained at ~20 °C in the flask. Stirring continued stirred at ~20 °C for 4 hours. Pd / C catalyst was filtered out through a 0.22 pm pore size membrane. Acetone and water were removed via rotary evaporation at ~20 °C and 9 torr for 2 hours. The resulting material was filtered through a 0.22 pm pore size membrane again. 551g of clear liquid MDOHM (1, 1,1,3, 5,5,5-heptamethyltrisiloxan-3-ol) was collected. Yield was 95 area% by GC.

[0046] Next, 331.5 g of MD’M was charged into a 4-neck 1000 ml flask equipped with a mechanical stirrer, a thermal couple, and an adapter to a N2 bubbler. 1.49 g of 4.7% BCF / toluenesolution was added to the flask. Under vigorous stirring, 346.1 g of the 1,1, 1,3, 5, 5, 5-heptamethyltrisiloxan-3-ol prepared as described above, was added into the flask slowly in 80 minutes via a peristaltic pump. The temperature in the flask was maintained at 60-65 °C.Additional BCF catalyst (0.75g of 4.7% BCF / toluene solution was added in 3 times) was added to the flask to keep the reaction ongoing. Stirring was continued at ~20 °C for 1 hour. 32 g of neutral alumina was added to the flask to remove BCF catalyst. The alumina was filtered out after stirring at ~20 °C for 3 hours. Volatiles were removed via rotary evaporator at 40 °C and 10 torr for 1 hour. 649.2g of clear liquid (3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane)) was collected. Yield was 95.8 %, and GC-FID analysis indicated the purity was 95.5 area % of 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane). The comparative examples and results are summarized below in Table 2.

[0047] In this Synthesis Example 6, 856.0 g of MD'M was charged into a 2000 ml flask equipped with mechanical stirrer, thermal couple, and N2 blanket. At 22 °C, 3.4 g BCF / toluene solution (5.38 % BCF with balance as toluene) was added into the flask, and a mixture of 70.2 g of trimethyl orthoformate (TMOF) and 3.9 g BCF / toluene solution (5.38 %) was added to the flask slowly via a peristaltic pump, i.e., at an addition rate of 1.0-1.2 ml / min. Temperature was controlled at 15 to 20 °C by dry ice cooled heat block. Feed time was 70 minutes. The mixture was stirred at 22 °C for 60 minutes, and then volatiles were removed via rotary evaporator at 80 °C and 1.5 torr to 2.0 torr for 30 minutes. 866.1g product was collected. Yield was 98.1%, and GC-FID peak area indicated the purity was 99.6 area % 3,3’-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) .Table 2< <

[0048] GC-MS analysis indicated the products from Synthesis Examples 2 &3 contained various impurities shown below in Table 3. Synthesis examples 2 and 3 demonstrated that loweryield and lower purity of M2TTM2 were obtained using DME and DGME instead of trimethyl orthoformate as in Synthesis Example 6.<Table 3 - Im purities in Synthesis Examples 2 and 3"&"

[0049] In Table 3, the species detected in synthesis example 2 made with DME were 266, 310, 458, 502, 606, and 754. The species detected in the synthesis example 3 made with DEGMEE were 238, 266, 282, 310, 430, 458, 502, 578, 606, and 650.

[0050] In this Example 1, to a 4 oz. squat jar the M2TTM2 prepared in Synthesis Example 6 (22.15 grams) and Si-H siloxane (3.85 g) were added. The solution was mixed and heated to 75 °C using a hot plate and a cross magnetic stir bar at 300 rpm. Once heated to 75 °C 1,5-hexadiene (200 pL) was added followed by SYL-OFF™ 4000 Catalyst (150 pL). A timer was started after the catalyst addition and stopped when the magnetic stir bar was no longer able to stir the solution. This was considered the gel time (10 minutes 40 seconds). The reaction mixture was held at 75 °C for ~4 hours, after which heating was removed and the sample cooled to room temperature. The sample was a soft gel, and after sitting overnight there was no free fluid observed. The final product was a clear slightly yellow gel.Industrial Applicability

[0051] The synthesis examples above demonstrate that 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) can be prepared by differing methods, with varying yield and purity. The 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) may be used in the preparation of silicone elastomer in addition to, or instead of, previously disclosed low molecular weight polysiloxanes. For example, 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) may be used in the method described in US Patent 5654362 and US Patent 5880210, both to Schulz, Jr., et al. in addition to, or instead of, the low molecular weight linear or cyclic polysiloxanes disclosed therein. The silicone elastomers described herein may be used in various end use applications, e.g., personal care applications such as antiperspirants, cosmetics, deodorants, and skin care compositions. The use of 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) described herein provides the benefit of minimizing or avoiding the use of cyclic polydiorganosiloxanes, and / or other polydiorganosiloxanes that can form cyclic polydiorganosiloxanes during preparation, storage, and / or use.Test Methods

[0052] Gas Chromatography (GC) Analysis was performed as follows: The GC analysis was performed using a Hewlett Packard HP 6890 Series GC System. To a glass GC syringe 0.3 pl of the test material was added. The sample was manually injected into the GC inlet and then the start button was pressed. The run conditions as well as the column type can be found below.| Gas Type | Helium |

[0053] Gas Chromatography Mass Spectrometry (GC-MS) Analysis was performed as follows: The GC-MS analysis was performed using an Agilent 7890 column program: 40°C (1 min) - 315°C (10 min) @ 10°C / min. The column, inlet, and detector information can be found below.&Definitions and Usage of Terms

[0054] Any feature or aspect of the invention may be used in combination with any other feature or aspect recited herein. All amounts, ratios, and percentages herein are by weight, unless otherwise indicated by the context of the specification. The articles ‘a’, ‘an’, and ‘the’ each refer to one or more, unless otherwise indicated by the context of specification. The singular includes the plural unless otherwise indicated by the context of the specification. The SUMMARY and ABSTRACT are hereby incorporated by reference. The amounts of all starting materials in a composition total 100%. Any feature or aspect of the invention may be used in combination with any other feature or aspect recited herein. The abbreviations used herein have the definitions in Table A.Table A - Abbreviations

[0055] It is to be understood that the appended claims are not limited to express and particular compounds, compositions, or methods described in the detailed description, which may varyamong embodiments, which fall within the scope of the appended claims. With respect to any Markush groups relied upon herein for describing particular features or aspects of various embodiments, different, special, and / or unexpected results may be obtained from each member of the respective Markush group independent from all other Markush members. Each member of a Markush group may be relied upon individually and or in combination and provides adequate support for specific embodiments within the scope of the appended claims.

Claims

CLAIMS:

1. A method for preparing a silicone elastomer composition, wherein the method comprises:(I) combining, under conditions to effect hydrosilylation reaction, starting materials comprisinga) a polyorganohydrogensiloxane;b) an alpha, omega-diene;in the presence of starting materials comprisingc) a hydrosilylation reaction catalyst, andd) 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane).

2. The method of claim 1, wherein a) the polyorganohydrogensiloxane comprises a unit formula selected from the group consisting ofal ) (R3SiOi / 2)2(R’2SiO2 / 2)a(R”HSiO2 / 2)b.a2) (HR2SiOi / 2)2(R’2SiO2 / 2)c,a3) (HR2SiOi / 2)2(R’2SiO2 / 2)a(R”HSiO2 / 2)b, anda combination of two or more thereof, whereineach R, R’, and R” is an independently selected alkyl group of 1 to 6 carbon atoms,subscript a is 0 to 250,subscript b is 1 to 250, andsubscript c is 0 to 250.

3. The method of claim 2, wherein a) the polyorganohydrogensiloxane comprises unit formula al); and each R, each R’, and each R” is methyl.

4. The method of any one of claims 1 to 3, wherein b) the alpha-olefin has formula CH2=CH-R2-CH=CH2, wherein R2is a divalent hydrocarbyl group of 1 to 20 carbon atoms.

5. The method of claim 4, wherein the alpha-olefin comprises 1,5-hexadiene.

6. The method of any one of claims 1 to 5, wherein c) the hydrosilylation reaction catalyst may be selected from the group consisting of chloroplatinic acid, chloroplatinic acid hexahydrate, and Karstedt's catalyst.

7. The method of any one of claims 1 to 6, wherein step (1) is performed with heating at a temperature of 60 °C to 90 °C for 8 minutes to 5 hours.

8. The method of any one of claims 1 to 7, wherein a) the polyorganohydrogensiloxane is used in an amount of 11 weight % to 16 weight %, b) the alpha, omega-diene is used in an amount of 0.4 weight % to 0.6 weight %, d) the 3,3'-oxybis(l ,1 ,1 ,3,5,5,5-heptamethyltrisiloxane) is used in an amount of 67 weight % to 82 weight %; each based on combined weights of starting materials a), b), and d); and c) the hydrosilylation reaction catalyst is used in an amount sufficient to provide 1 to 6000 ppm of platinum group metal, based on combined weights of starting materials a), b), and d).

9. The method of any one of claims 1 to 8, wherein the method further comprises preparing d) the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane) by a method comprising:optionally 1) combining, under conditions to effect hydrolysis reaction, starting materials comprising1,1,1 ,3,5,5,5-heptamethyltrisiloxane,water, anda palladium catalyst,optionally a solvent, andoptionally a buffer,thereby forming an intermediate comprising 1,1,1,3,5,5,5-heptamethyltrisiloxan- 3-ol;optionally 2) purifying the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol;3) combining, under conditions to effect dehydration reaction, starting materials comprisingthe l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol,1,1, 1 ,3,5,5,5-heptamethyltrisiloxane, and tris(pentafluorophenyl)borane, thereby preparing the product comprising 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane); andoptionally 4) purifying the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane).

10. The method of claim 9, wherein step 3) is performed by a technique comprising: i) mixing starting materials comprising the 1,1,1,3,5,5,5-heptamethyltrisiloxane and the tris(pentafluorophenyl)borane, thereby preparing a mixture, andii) adding E) the l,l,l,3,5,5,5-heptamethyltrisiloxan-3-ol to the mixture.

11. The method of any one of claims 1 to 8, wherein the method further comprises preparing d) the 3,3’-<>xybis( 1 , 1 , 1 ,3,5,5,5-heptamethyltrisiloxanej by a method comprising:7) mixing starting materials comprising 1,1,1,3,5,5,5-heptamethykrisiloxane and tris(pentafluorophenyl)borane, wherein the tris(pentafluorophenyl)borane is used in an amount sufficient to provide 50 ppm by weight to 200 ppm by weight based on the 1,1,1 , 3, 5,5,5-heptamethyltrisiloxane, thereby preparing a first mixture;2) mixing trimethyl orthoformate and tris(pentafluorophenyl)borane, wherein the tris(pentafluorophenyl)borane is used in an amount sufficient to provide 100 ppm by weight to 300 ppm by weight based on the trimethyl orthoformate, thereby preparing a second mixture; and3) feeding the second mixture into the first mixture under conditions to control temperature at 10 °C to 30 °C, thereby forming the product comprising 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane); andoptionally 4) purifying the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane).

12. The method of claim 11, further comprising: 5) mixing at 23 °C ± 3 °C for at least 1 hour after step 5) and before step 4), when present.

13. The method of any one of claims 1 to 12, wherein combining the starting materials in step (I) comprises the starting materials mixing under shear.

14. A silicone elastomer composition prepared by the method of any one of claims 1 to 13, wherein the silicone elastomer composition comprises:70 weight % to 98 weight % of the 3,3'-oxybis(l,l,l,3,5,5,5-heptamethyltrisiloxane), and 2 weight % to 30 weight % of a silicone elastomer, which is a hydrosilylation reaction product of starting materials comprising a) the polyorganohydrogensiloxane and b) the alpha, omega-diene.

15. A personal care composition comprising the silicone elastomer composition of claim 14.

Images