Organosiloxane and methods for the preparation and use thereof

Abstract

An organosiloxane may have formula where each subscript n independently has an average value of 2 to 18, each R is an independently selected monovalent hydrocarbyl group, and each R3 is independently selected from the group consisting of H and a functional group containing a moiety selected from the group consisting of an acrylate group, an alcohol group, an alkoxy group, an epoxy group, an isocyanate group, a methacrylate group, and a urethane group is disclosed. The method for preparing the organosiloxane includes dehydrogenative condensation reaction of an aromatic silanediol and a cyclic polyorganohydrogensiloxane in the presence of a Lewis acid catalyst. The method may optionally further includes hydrosilylation reaction to react functional groups onto the cyclic siloxane moieties. The organoiloxane is useful as a crosslinker or a co-crosslinker in silicone release coating compositions or an adhesion promoter in curable liquid silicone rubber compositions.

Description

ORGANOSILOXANE AND METHODS FOR THE PREPARATION AND USE THEREOFCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 592218 filed on 23 October 2023 under 35 U.S.C. § 119 (e). U.S. Provisional Patent Application Serial No. 63 / 592218 is hereby incorporated by reference.FIELD

[0002] An organosiloxane and methods for its preparation and use are disclosed. The organosiloxane comprises two cyclic organosiloxane moieties bonded to a silicon atom. The organosiloxane is useful in curable silicone compositions as an adhesion promoter or as a crosslinker or co-crosslinker.INTRODUCTION

[0003] Methods for making polyfunctional organosiloxane crosslinkers having linear polydiorganosiloxane backbones with cyclic siloxane endblockers have been proposed using platinum catalyzed reaction of cyclic polyorganohydrogensiloxanes with either vinyl terminated polydiorganosiloxanes or hydroxyl terminated polydiorganosiloxanes. These methods suffer from the drawback of poor ability to control structure and molecular weight of the products. U.S. Patent Application Publication 2022-0025125 discloses a method for making a polyfunctional organosiloxane comprising a linear polydiorganosiloxane backbone with cyclic siloxane endblockers. The polyfunctional organosiloxane is useful in curable compositions, e.g., as a crosslinker.

[0004] Adhesion promoters are widely used to improve the adhesion of various silicone products (e.g., sealants, adhesives, and elastomers) to different inorganic and organic substrates. The choice of adhesion promoter is often specific to the composition and application, which requires the matching on properties such as chemical reactivity, solubility characteristics, compatibility, and thermal stability. Faster cure times at lower temperatures are desirable for curable silicone compositions such as liquid silicone rubber (LSR) compositions. However, a challenge frequently encountered at low temperature cure for LSR compositions is the lack of developing fast and strong adhesion for different substrates (e.g., PBT, PA, PC, Al, and / or Glass).SUMMARY

[0005] An organosiloxane, and methods for preparation and use of the organosiloxane, are provided. The organosiloxane comprises formula:each subscript n independently has an average value of 2 to 18, each R is an independently selected monovalent hydrocarbyl group, and each R3is independently selected from the group consisting of H and a functional group containing a moiety selected from the group consisting of an acrylate group, an alcohol group, an alkoxy group, an epoxy group, an isocyanate group, a methacrylate group, and a urethane group;R1is a monovalent hydrocarbyl group selected from an alkyl group and an aromatic group, andR2is a monovalent aromatic group.DETAILED DESCRIPTION

[0006] The organosiloxane introduced above may have silyl hydride functionality, i.e., the organosiloxane may be an organohydrogensiloxane. A method for preparing a reaction product comprising the organohydrogensiloxane comprises the steps of:1) combining, under conditions to effect dehydrogenative condensation reaction, starting materials comprisingA) a Lewis acid catalyst comprising a fluorinated arylborane;R1HO - Si - OHB) an aromatic silane diol of formula R2, whereR1is a monovalent hydrocarbyl group selected from an alkyl group and an aromatic group, andR2is a monovalent aromatic group; andC) a cyclic polyorganohydrogensiloxane of formula (RHSiO2 / 2)v, where subscript v has an average value of 4 to 20; and each R is an independently selected monovalent hydrocarbyl group; thereby preparing the reaction product comprising the organohydrogensiloxane and a by-product comprising H2.The starting materials in step 1 ) may optionally further comprise D) a solvent.

[0007] The method for preparing the reaction product comprising the organohydrogensiloxane may optionally further comprise one or more additional steps. The method may further comprise: step 2) during and / or after step 1), removing the Hi generated during formation of the organohydrogensiloxane, and / or 3) neutralizing residual A) Lewis acid catalyst in the dehydrogenative condensation reaction product. By-product Hi may be removed by any convenient means, such as stripping and / or burning. Neutralizing may be performed by adding E) a neutralizing agent to the dehydrogenative condensation reaction product and thereafter filtering the dehydrogenative condensation reaction product. Steps 2) and 3) may be performed in any order. If a particulate by-product is present, e.g., as a result of neutralization, the method may further comprise 4) removing a particulate such as alumina after neutralization by any convenient means, such as filtration. One skilled in the art would be able to select appropriate optional additional steps to recover the organohydrogensiloxane from the dehydrogenative condensation reaction product, if desired.

[0008] One or more of the method steps 1) to 4) described above may be performed at a temperature of 0 °C to 100 °C, alternatively 0 °C to 65 °C, alternatively 0 °C to 60 °C, alternatively 0 °C to 50 °C, alternatively 0 °C to 35 °C, alternatively 0 °C to 30 °C, and alternatively 0 to < 30 °C. Alternatively, step 1) may be performed at the temperature of 0 °C to 30 °C, alternatively 0 °C to < 30 °C, alternatively 0 °C to 25 °C, alternatively 0 °C to 20 °C, alternatively 0 °C to 15 °C, alternatively 0 °C to 10 °C, and alternatively < 30 °C. Without wishing to be bound by theory, it is thought that performing this method, particularly step 1), at relatively low temperatures (e.g., 30 °C or less, alternatively 25 °C or less, alternatively 20 °C or less, and alternatively 10 °C or less) may minimize or prevent deactivation of A) the Lewis acid catalyst.

[0009] The starting materials used in step 1) of the method for preparing the dehydrogenative condensation reaction product comprising the organohydrogensiloxane (alternatively the starting materials used in step 1) and any optional additional steps such as 2), 3), and 4) of this method) may be free of platinum group metal catalysts. The resulting dehydrogenative condensation reaction product, and the organohydrogensiloxane, may also be free of platinum group metal catalysts. “Free of’ as used herein includes none, alternatively an amount non-detectable by inductively coupled plasma mass spectrometry (ICP-MS), and alternatively an amount insufficient to cause performance problems, of release coatings prepared from release coating compositions including the organohydrogensiloxane made by the method described herein. Without wishing to be bound by theory, it is thought that the absence of platinum group metal catalysts may also improve storage stability of the organohydrogensiloxane, as compared to anorganohydrogensiloxane that contains the platinum group metal catalyst.Starting Material A) Lewis Acid Catalyst

[0010] Starting material A) in the method described herein is a Lewis acid catalyst comprising a fluorinated arylborane. The Lewis acid catalyst may be a trivalent boron compound with at least one perfluoroaryl group per molecule, alternatively 1 to 3 perfluoroaryl groups per molecule, alternatively 2 to 3 perfluoroaryl groups per molecule, and alternatively 3 perfluoroaryl groups per molecule. The perfluoroaryl groups may have 6 to 12 carbon atoms, alternatively 6 to 10 carbon atoms, and alternatively 6 carbon atoms. Suitable Lewis acid catalysts are known in the art, for example, as disclosed in PCT Patent Application Publication WO2021 / 262940; U.S. Patent Application Publication 2023 / 0123215; U.S. Patent Application Publication 2023 / 0151156; and U.S. Patent Application Publication 2023 / 0151157.Alternatively, the Lewis Acid catalyst may be selected from the group consisting of (C5F4)(C6F5)2B; (C5F4)3B; (C6F5)BF2; BF(C6F5)2; B(C6F5)3; BC12(C6F5); BC1(C6F5)2; (C6F5)B(OH)2; (C6F5)2BOH; (C6F5)2BH; (C6F5)BH2; (C7HH)B(C6F5)2; (C6F5)2B(OC2H5); or (CeF5)2B-CH2CH2Si(CH3). Alternatively, the Lewis acid catalyst may be selected from (C5F4)(C6F5)2B; (C5F4)3B; (C6F5)BF2; BF(C6F5)2; B(C6F5)3; BC12(C6F5); BC1(C6F5)2;(C6F5)B(OH)2; (C6F5)2BOH; (C6F5)2BH; (C6F5)BH2; (C7HII)B(C6F5)2; (C6F5)2B(OC2H5); or (C6Fs)2B-CH2CH2Si(CH3). Alternatively, the Lewis acid catalyst may comprise, or may be, tris(pentafluorophenyl)borane of formula B / CeFsh. Such Lewis acid catalysts are commercially available from, e.g. , Millipore Sigma of St. Louis, Missouri, USA. The amount of starting material A) will depend on the type and amount of other starting materials used, however, starting material A) may be present in an amount of 50 ppm to 6000 ppm based on combined weights of starting materials A), B) and C). Alternatively, the amount may be 50 ppm to 600 ppm on the same basis.Starting Material B) Aromatic Silane Diol Compound

[0011] Starting material B) is an aromatic silane diol of formulawhere R1is a monovalent hydrocarbyl group selected from an alkyl group and an aromatic group, and R2is a monovalent aromatic group. The alkyl group may have 1 to 20 carbon atoms. The aryl group may have 6 to 20 carbon atoms. Suitable alkyl groups include methyl, ethyl, and propyl (including n-propyl and isopropyl). The aromatic groups may be monocyclic or polycyclic, alternatively monocyclic. Suitable aromatic groups for R1include phenyl, tolyl, xylyl, 1 -phenylethyl, 2-phenylethyl, 2-methyl-2-phenylethyl, 3-phenylpropyl, 4-phenylbutyl,benzyl, styryl, naphthyl and anthracenyl. Alternatively, the aromatic group for R1may be selected from the group consisting of phenyl, tolyl and xylyl. Alternatively, the aromatic group for R1may be selected from the group consisting of phenyl and tolyl. Alternatively, R1may be selected from methyl and phenyl. Alternatively, R1may be phenyl.

[0012] In the formula for the aromatic silane diol, R2is an aromatic group. The aromatic group for R2is as described and exemplified above. When R1and R2are both aromatic groups, they may be the same or different. Alternatively, R2may be selected from the group consisting of phenyl, tolyl and xylyl. Alternatively, R2may be selected from the group consisting of phenyl and tolyl. Alternatively, R2may be phenyl.

[0013] Aromatic silane diols suitable for use as starting material B) may be made by known methods, for example, as disclosed in U.S. Patent 3,398,179 to Flatt, and U.S. Patent 2,899,453 to Spector, et al. Aromatic silane diols are commercially available. For example, diphenylsilane diol (CAS #: 947-42-2) is available from Gelest, Inc. of Morrisville, Pennsylvania, USA. Phenyl, methyl- silane diol (CAS #: 3959-13-5) is available from Biosynth of the UK and from TLC Pharmaceutical Standards Ltd. of Ontario, Canada. Alternatively, starting material B) may be selected from the group consisting of diphenyl- silane diol; phenyl, methyl- silane diol; or a combination of both diphenyl- silane diol and phenyl, methyl- silane diol. Alternatively, starting material B) may be diphenyl- silane diol.Starting Material C) Cyclic Polyorganohydrogensiloxane

[0014] Starting material C) for the method described herein is a cyclic polyorganohydrogensiloxane of formula C-l): (RHSiO2 / 2)v, where subscript v has an average value of 4 to 20, and each R is an independently selected alkyl group. Alternatively, subscript v may have an average value of 4 to 10, alternatively 4 to 8, and alternatively 4 to 6.Alternatively, subscript v may have an average value of 4 to 6, alternatively 4 to 5, alternatively 5, and alternatively 4.5 to 5. In formula C-l), R may be an alkyl group of 1 to 6 carbon atoms. Alternatively, R may be selected from methyl, ethyl, or propyl. Alternatively, each R may be methyl.

[0015] Examples of suitable cyclic polyorganohydrogensiloxanes for starting material C) include tetramethylcyclotetrasiloxane, pentamethylcyclopentasiloxane, hexamethylcyclohexasiloxane, and combinations of two or more thereof. Suitable cyclic polyorganohydrogensiloxanes are known in the art and are commercially available, e.g., from Dow Silicones Corporation of Midland, Michigan, USA.

[0016] The amounts of starting materials B) and C) depend on various factors including the OH content of B) the aromatic silane diol and the silicon bonded hydrogen (SiH) content of C) the cyclic polyorganohydrogensiloxane. However, amounts are sufficient to provide a molarratio of SiH in starting material C) to OH in starting material B) (SiH : OH ratio) of 10:1 to 40:1, alternatively 10:1 to 20:1, and alternatively 10:1 to 15:1.Starting Material D) Solvent

[0017] A solvent may be used in the method. The solvent may facilitate introduction of certain starting materials, such as starting material A) the Lewis acid catalyst. Solvents used herein are those that help fluidize the starting materials but essentially do not react with any of these starting materials. Solvent may be selected based on solubility the starting materials and volatility of the solvent. The solubility refers to the solvent being sufficient to dissolve and / or disperse the starting materials. Volatility refers to vapor pressure of the solvent.

[0018] Suitable solvents may be hydrocarbons. Suitable hydrocarbons include aromatic hydrocarbons such as benzene, toluene, or xylene; and / or aliphatic hydrocarbons such as heptane, hexane, or octane. Alternatively, the solvent may be a halogenated hydrocarbon such as dichloromethane, 1,1,1 -trichloroethane or methylene chloride.

[0019] The amount of solvent can depend on various factors including the type of solvent selected and the amount and type of other starting materials selected. However, the amount of solvent may range from 0. 1% to 99%, alternatively 2% to 50%, based on combined weights of starting materials A), B), and C).Starting Material E) Neutralizing agent

[0020] Starting material E) is neutralizing agent that may optionally be used to neutralize A) the Lewis acid catalyst after the dehydrogenative condensation reaction product forms.Alumina, triphenyl amine, triphenyl phosphine, and phenylacetylene are suitable neutralizing agents. Neutralizing agents are known in the art and are commercially available, e.g., from Millipore Sigma. The amount of neutralizing agent depends on various factors including the amount of starting material A), however, starting material E) may be present in an amount sufficient to provide a weight ratio of neutralizing agent to Lewis acid catalyst (E:A ratio) of 1:1 to 1000: 1. Alternatively, when the neutralizing agent is triphenyl phosphine or phenylacetylene, the E:A ratio may be 1: 1 to 20: 1. Alternatively, when the neutralizing agent is alumina, the E:A ratio may be 100:1 to 1000:1. Suitable neutralizing agents such as those described above are commercially available from various sources including Millipore Sigma.Reaction Product of the Method

[0021] The dehydrogenative condensation reaction product of the method described above comprises a) the organohydrogensiloxane and the by-product comprising H2. The reaction product may further comprise unreacted starting materials, residual A) Lewis acid catalyst, and / or D) solvent, when used. The organohydrogensiloxane a) comprises formula a-1):independently has an average value of 2 to 18 (i.e., n = (v - 2), where subscript v has an average value of 4 to 20 as defined above), and groups R, R1, and R2are as described above.Alternatively, each subscript n independently may have an average value from 2 to 4, alternatively > 2 to 4, alternatively > 2 to 3, and alternatively 2.5 to 3, and alternatively 3.

[0022] The amounts of starting materials B) and C) may be used in amounts such that the molar ratio of cyclic polyorganohydrogensiloxane : aromatic silanediol, C:B, is > 4: 1, alternatively > 6: 1. Alternatively, starting materials B) and C) may be used in amounts such that the content of silicon bonded hydrogen atoms in starting material C) to content of silicon bonded hydroxyl groups in starting material B) (SiH : OH mole ratio) is 10:1 to 40:1, alternatively 10:1 to 20: 1, and alternatively 10:1 to 15:1. Alternatively, SiH : OH ratio may be at least 8:1, at least 9:1, alternatively at least 12: 1, alternatively at least 13: 1, alternatively at least 14: 1, alternatively at least 15: 1, and alternatively at least 45:1; while at the same time, SiH : OH ratio may be up to 180 : 1, alternatively up to 90: 1. The organohydrogensiloxane described above may be used in silicone release coating compositions, e.g., as a crosslinker or co-crosslinker. Alternatively, the organohydrogensiloxane may be used as an adhesion promoter in a curable silicone composition, such as a liquid silicone rubber (LSR) composition. Alternatively, the organohydrogensiloxane may be used as an intermediate for further reaction, as follows.Method for Making the Functionalized Organosiloxane

[0023] The method described above may further comprise functionalizing the above described organohydrogensiloxane to form a functionalized organosiloxane. The method for functionalizing the organohydrogensiloxane comprises: i) practicing the method comprising step 1), and optionally one or more of the additional steps, described above to prepare the reaction product comprising the functionalized organosiloxane, and ii) combining, under conditions to effect hydrosilylation reaction, starting materials comprising the dehydrogenative condensation reaction product described above, or a) the organohydrogensiloxane;b) a hydrosilylation reaction catalyst; and c) a reactive species having an average, per molecule at least one aliphatically unsaturated group capable of undergoing an addition reaction with a silicon bonded hydrogen atom of starting material a) the organohydrogensiloxane, wherein starting material c) further comprises one or more functional groups per molecule; thereby preparing a hydrosilylation reaction product.

[0024] Briefly stated, this method may be performed by modifying the method described in U.S. Patent 9,593,209. Starting material a) the organohydrogensiloxane described hereinabove may be combined with the reactive species and the hydrosilylation reaction catalyst (described as components c) and d), respectively) in the amounts and under conditions described in U.S. Patent 9,593,209 at col. 8, line 44 to col. 10, line 47. The hydrosilylation reaction may be carried out batchwise or continuous in any suitable equipment, such as a jacketed reactor with agitation means such as an impeller or baffles.

[0025] In the method described herein, the hydrosilylation reaction may be performed by optionally dissolving or dispersing b) the hydrosilylation reaction catalyst in d) a solvent (such as that described above as starting material D)) to facilitate mixing. Starting materials comprising a) the organohydrogensiloxane and c) the reactive species may be placed in the reactor with b) the hydrosilylation reaction catalyst, and the other of c) the reactive species and a) the organohydrogensiloxane may be fed into the reactor continuously or intermittently to control any exotherm. The reactor may be heated or cooled, such that the reaction mixture may be maintained a temperature of 50 °C to 150 °C, alternatively 60 °C to 100 °C, alternatively 70 °C to 90 °C.

[0026] Alternatively, the method for functionalizing the organohydrogensiloxane to form the functionalized organosiloxane may optionally further comprise an additional step. For example, this method may further comprise iii) adding e) a hydrosilylation reaction inhibitor to the hydrosilylation reaction product; and / or iv) recovering the functionalized organosiloxane from the hydrosilylation reaction product. Recovering may be performed by any convenient means, such as stripping and / or distillation with heating, and optionally under vacuum.Starting Material b) Hydrosilylation Reaction Catalyst

[0027] Hydrosilylation reaction catalysts suitable for starting material b) in the method for functionalizing the organohydrogensiloxane are known in the art and are commercially available. Hydrosilylation reaction catalysts include platinum group metal catalysts. Such hydrosilylation catalysts can be a metal selected from platinum, rhodium, ruthenium, palladium, osmium, and iridium. Alternatively, the hydrosilylation catalyst may be a compound of such a metal, for example, chloridotris(triphenylphosphane)rhodium(I) (Wilkinson’s Catalyst), arhodium diphosphine chelate such as | l,2-bis(diphenylphosphino)ethane|dichlorodirhodium or [l,2-bis(diethylphospino)ethane]dichlorodirhodium, chloroplatinic acid (SpeieR3s Catalyst), chloroplatinic acid hexahydrate, platinum dichloride, and complexes of said compounds with low molecular weight organopolysiloxanes or platinum compounds microencapsulated in a matrix or coreshell type structure. Complexes of platinum with low molecular weight organopolysiloxanes include l ,3-diethenyl-l ,l ,3,3-tetramethyldisiloxane complexes with platinum (Karstedt’s Catalyst) and methylvinylcyclosiloxane complexes with platinum (Ashby’s Catalyst). These complexes may be microencapsulated in a resin matrix. Alternatively, a hydrosilylation catalyst may comprise l,3-diethenyl-l,l,3,3-tetramethyldisiloxane complex with platinum. Exemplary hydrosilylation catalysts are described in U.S. Patents 3,159,601; 3,220,972; 3,296,291; 3,419,593; 3,516,946; 3,814,730; 3,989,668; 4,784,879; 5,036,117; and 5,175,325; and EP 0 347 895 B. Microencapsulated hydrosilylation catalysts and methods of preparing them are known in the art, as exemplified in U.S. Patents 4,766,176 and 5,017,654. The amount used may be sufficient to provide 1 ppm to 1,000 ppm of platinum group metal based on combined weights of starting materials a), b), and c).Starting Material c) reactive species

[0028] Starting material c) the reactive species described above for functionalizing the organohydrogensiloxane may comprise a silane of formula c-1): R4ySiRs<4-y), where subscript y is 1 to 3, each R4is the aliphatically unsaturated group capable of undergoing an addition reaction, and each R5is an organic group containing a reactive functionality. Alternatively, subscript y may be 1 to 2. Alternatively, subscript y may be 1. Each R4may be independently selected from the group consisting of alkenyl (such as vinyl, allyl, and hexenyl) and alkynyl (such as propynyl or hexynyl). Alternatively, each R4may be vinyl. Alternatively, each R4may be allyl. Each R5may be an organic moiety comprising a functional group selected from an acrylate group, an alcohol group, an alkoxy group, an epoxy group, an isocyanate group, a methacrylate group, or a urethane group. Alternatively, each R5may be an organic moiety comprising a functional group selected from an acrylate group, an organic group containing an epoxy group, and an organic moiety containing a methacrylate group. Alternatively, each R5may be an organic moiety comprising an epoxy group. Suitable silanes are known in the art and are commercially available, e.g. , from Dow Silicones Corporation of Midland, Michigan, USA or Gelest, Inc. of Morrisville, Pennsylvania, USA. Exemplary silanes include allyltrimethoxysilane, allyltriethoxysilane, or a combination thereof.

[0029] Alternatively, starting material c) may comprise an organic compound that does not contain a silicon atom, e.g., a reactive species of formula c-2): R6R7, where each R6is an aliphatically unsaturated group capable of undergoing an addition reaction, and each R7is thereactive group. Each R6may be independently selected from the group consisting of alkenyl (such as vinyl, allyl, and hexenyl) and alkynyl (such as propynyl or hexynyl). Alternatively, each R6may be vinyl. Alternatively, each R6may be allyl. Each R7may be independently an organic moiety comprising a functional group selected from an acrylate group, an alcohol group, an alkoxy group, an epoxy group, an isocyanate group, a methacrylate group, or a urethane group. Alternatively, each R7may be an organic moiety comprising a functional group selected from an acrylate group, an epoxy group, or a methacrylate group. Alternatively, each R7may be an organic moiety comprising an epoxy group. Examples of suitable compounds of formula c-2) include allyl acrylate, allyl glycidyl ether, allyl methacrylate, and combinations thereof. Alternatively, c-2) may be allyl glycidyl ether. Alternatively, c-2) may be allyl methacrylate. Suitable compounds of formula c-2) are known in the art and are commercially available, e.g., from Millipore Sigma.

[0030] The amount of c) the reactive species depends on various factors including the desired degree of substitution of the organosiloxane. For example, the amount of reactive species may be sufficient to react all silicon bonded hydrogen atoms in a) the organosiloxane or an excess, e.g., a molar ratio of silicon bonded hydrogen atoms from a) the organosiloxane to aliphatically unsaturated groups from c) the reactive species (SiH: vinyl ratio) may be < 1: 1 to 1:1. Alternatively, it may be desirable for the functionalized organosiloxane to have both silicon bonded hydrogen atoms and functional groups derived from c) the reactive species. In this intance, SiH: Vi ratio may be > 1:1. Alternatively, starting materials a) and c) may be used in amounts such that an average of two silicon bonded hydrogen atoms per molecule are replaced with functional groups derived from c) the reactive species via the hydrosilylation reaction. e) Hydrosilylation Reaction Inhibitor

[0031] The hydrosilylation reaction inhibitor may be for example, an acetylenic alcohol such as methyl butynol or ethynyl cyclohexanol, a silylated acetylenic alcohol, an unsaturated hydrocarbon diester; a conjugated ene-yne, an olefinic siloxane, a maleate, a fumarate, or a combination thereof. The amount of inhibitor may be an amount effective to deactivate b) the hydrosilylation reaction catalyst, e.g., to prevent further reaction of the organosiloxane during recovery of the organosiloxane. The amount of inhibitor selected depends on variou sfactors including the type and amount of catalyst and inhibitor selected, however, the amount may be 0.00001 to 3 parts by weight, per 100 parts by weight of c) the reactive species. Suitable hydrosilylation reaction inhibitors are known in the art and are described, for example, described as ingredient i) in U.S. Patent 9,593,209 at col. 15, line 35 to col. 16, line 17.

[0032] The starting materials used in the method for functionalizing the organohydrogensiloxane may optionally further comprise one or more additional startingmaterials. The additional starting materials may be those additional ingredients disclosed in U.S. Patent 9,593,209 at col. 10, line 48 to col. 16, line 17. The additional starting materials selected from the group consisting of filler, with or without treating agent, non-reactive resin, chain extender, endcapper, and hydrosilylation reaction catalyst inhibitor as described above.

[0033] The method described above produces a hydrosilylation reaction product comprising a’) a functionalized organopolysiloxane. The functionalized organosiloxane comprises formula a’-l):subscript n and R are as described above, and each R8is independently selected from the group consisting of H and a functional group (which is derived from c) the reactive species via hydrosilylation reaction of R4or R6, as described above), with the proviso that at least one R8per molecule is the functional group (i.e., at least one instance of R8per molecule is not hydrogen). Alternatively, 1 to 4 instances of R8per molecule are functional groups (i.e., other than hydrogen). Alternatively 1 to 3, alternatively 1 to 2, and alternatively an average of two instances of R8per molecule are the functional groups (other than hydrogen). Alternatively, one instance of R8on each cyclic siloxane ring may be the functional group and the other instances of R8may be H. The functional group for R8is derived from starting material c) the reactive species described above. The functional group for R8may be independently selected from the group consisting of R4SiR5(4-y), and R6R7, where R5and R7are as described above, and R4and R6are divalent hydrocarbon groups produced via hydrosilylation reaction of the aliphatically unsaturated group of starting material c) the reactive species and a silicon bonded hydrogen atom of starting material a) the organosiloxane. Alternatively, in formula a’-l) each subscript n may independently have an average value of 2 to 4, alternatively > 2 to 4, alternatively 2 to 3, alternatively > 2 to 3, alternatively 2, and alternatively 3.

[0034] The functionalized organosiloxane prepared as described above may be used as an adhesion promoter in a curable silicone composition, such as a liquid silicone rubber composition.Curable Silicone Composition

[0035] The products, i.e., a) the organohydrogensiloxane, and a’) the functionalized organosiloxane are useful in curable silicone compositions as adhesion promoters.Alternatively, a) the organosiloxane may be useful as a crosslinker or co-crosslinker in hydrosilylation reaction curable compositions, such as silicone release coating compositions.

[0036] A curable silicone composition may comprise: (I) one or more of the above described reaction products, e.g., a) the organohydrogensiloxane, and / or a’) the functionalized organosiloxane; and (II) a curable silicone composition. The curable silicone composition may be a liquid silicone rubber (LSR) composition, and one or both of a) the organohydrogensiloxane and a’) the functionalized organopolysiloxane may be added thereto as an adhesion promoter, i.e., that increases adhesion of a silicone rubber (prepared by curing the LSR composition) as compared to a silicone rubber prepared from the same LSR composition that does not contain the above described a) organohydrogensiloxane or a’) functionalized organosiloxane as adhesion promoter.

[0037] Alternatively, the curable silicone composition may be a silicone release coating composition, such as that described in U.S. Patent Application Publication 2022-0025125, in which a) the organohydrogensiloxane described herein is used in addition to, or instead of, the polyfunctional organohydrogensiloxane of U.S. Patent Application Publication 2022-0025125. Method of Use

[0038] A method of preparing an article with the curable silicone composition comprises 1 ) disposing the curable silicone composition on the substrate. The method further comprises 2) curing the curable silicone composition on the substrate. Curing may be performed by any convenient means. For example, the curable silicone composition may cure by heating at an elevated temperature, e.g., 50 °C to 180 °C, alternatively 50 °C to 120 °C, and alternatively 50 °C to 90 °C to give the article, which comprises a cured silicone (product prepared by curing the curable silicone composition) adhered to the substrate. One skilled in the art would be able to select an appropriate temperature depending on various factors including the selection of optional starting materials in the curable silicone composition and the substrate material of construction.

[0039] The curable silicone composition may be disposed or dispensed on the substrate in any suitable manner. Typically, the curable composition is applied in wet form via a wet coating technique. The curable silicone composition may be applied by i) spin coating; ii) brush coating; iii) drop coating; iv) spray coating; v) dip coating; vi) roll coating; vii) flow coating; viii) slot coating; ix) gravure coating; x) Meyer bar coating; or xi) a combination of any two or more of i) to x). Typically, disposing the curable silicone composition on the substrate results in a wet deposit on the substrate, which is subsequently cured to give the article, which comprises a cured silicone (e.g., coating or elastomer) formed from the curable silicone composition on the substrate.

[0040] The substrate is not limited and may be any substrate. The substrate may have an integrated hot plate or an integrated or stand-alone furnace for curing the wet deposit. The substrate may optionally have a continuous or non-continuous shape, size, dimension, surface roughness, and other characteristics.

[0041] The substrate may comprise a plastic, which maybe a thermosetting and / or thermoplastic. However, the substrate may alternatively be glass, metal (e.g., aluminum or steel), paper, wood, cardboard, paperboard, a silicone, or polymeric materials, or a combination thereof.

[0042] Specific examples of suitable substrates include paper substrates such as Kraft paper, polyethylene coated Kraft paper (PEK coated paper), and regular papers; polymeric substrates such polyamides (PA); polyesters such as polyethylene terephthalates (PET), polybutylene terephthalates (PET), polytrimethylene terephthalates (PTT), polyethylene naphthalates (PEN), and liquid crystalline polyesters; polyolefins such as polyethylenes (PE), polypropylenes (PP), and polybutylenes; styrenic resins; polyoxymethylenes (POM); polycarbonates (PC); polymethylenemethacrylates (PMMA); polyvinyl chlorides (PVC); polyphenylene sulfides (PPS); polyphenylene ethers (PPE); polyimides (PI); polyamideimides (PAI); polyetherimides (PEI); polysulfones (PSU); polyethersulfones; polyketones (PK); poly etherketones; polyvinyl alcohols (PVA); polyetheretherketones (PEEK); polyetherketoneketones (PEKK); poly arylates (PAR); polyethemitriles (PEN); phenolic resins; phenoxy resins; celluloses such as triacetylcellulose, diacetylcellulose, and cellophane; fluorinated resins, such as polytetrafluoroethylenes; thermoplastic elastomers, such as polystyrene types, polyolefin types, polyurethane types, polyester types, polyamide types, polybutadiene types, polyisoprene types, and fluoro types; and copolymers, and combinations thereof. Alternatively, the substrate may be a substrate useful in the electronics industry, such as polybutylene terephthalate (PBT), polyamide (PA), or polycarbonate (PC).

[0043] The curable silicone composition, or wet deposit, may be cured at the elevated temperature for a period of time. The period of time is typically sufficient to effect curing, i.e., cross-linking, of the curable silicone composition. The period of time may be greater than 0 to 8 hours, alternatively greater than 0 to 2 hours, alternatively greater than 0 to 1 hour, alternatively greater than 0 to 30 minutes, alternatively greater than 0 to 15 minutes, alternatively greater than 0 to 10 minutes, alternatively greater than 0 to 5 minutes, alternatively greater than 0 to 2 minutes. The period of time depends on various factors including on the elevated temperature is utilized, the temperature selected, desired thickness of the cured silicone, and the presence of absence of any solvent in the curable silicone composition.

[0044] Curing the curable silicone composition typically may have a dwell time of 0. 1 secondand 50 seconds; alternatively 1 second to 10 seconds; and alternatively 0.5 second to 30 seconds. Dwell time selected may depend on the substrate selection, temperature selected, and line speed. Dwell time, as used herein, refers to the time during which the curable composition, or wet deposit, is subjected to the elevated temperature. Dwell time is distinguished from cure time, as there may be ongoing curing even after the curable silicone composition, wet deposit, or partially cured reaction intermediary thereof is no longer subjected to the elevated temperature, which typically initiates curing. Alternatively, the coated article may be prepared on a conveyor belt in an oven, and the dwell time may be calculated by dividing a length of the oven (e.g. in meters) by a line speed of the conveyor belt (e.g. in meters / sec).

[0045] The period of time may be broken down into cure iterations, e.g. a first-cure and a postcure, with the first-cure being, for example, one hour and the post cure being, for example, three hours. The elevated temperature may be independently selected from any temperature above room temperature in such iterations, and may be the same in each iteration.

[0046] Depending on a thickness and other dimensions of the cured silicone and substrate, the article can be formed via an iterative process. For example, a first deposit may be formed and subjected to a first elevated temperature for a first period of time to give a partially cured deposit. Then, a second deposit may be disposed on the partially cured deposit and subjected to a second elevated temperature for a second period of time to give a second partially cured deposit. The partially cured deposit will also further cure during exposure to the second elevated temperature for the second period of time. A third deposit may be disposed on the second partially cured deposit and subjected to a third elevated temperature for a third period of time to give a third partially cured deposit. The second partially cured deposit will also further cure during exposure to the second elevated temperature for the second period of time. This process may be repeated, for example, 1 or more times, such as 1 to 50 times, to build the article as desired. A composite of partially cured layers may be subjected to a final post-cure, e.g. at an elevated temperature and period of time above. Each elevated temperature and period of time may be independently selected and may be the same as or different from one another. When the article is formed via the iterative process, each deposit may also be independently selected and may differ in terms of starting materials selected in the curable silicone composition, their amounts, or both. Alternatively still, each iterative layer may be fully cured, rather than only being partially cured, in such an iterative process. Alternatively, the deposit may comprise a wet film. Alternatively, the iterative process may be wet-on-wet, depending on a cure state of the partially cured layer. Alternatively, the iterative process may be wet-on-dry.

[0047] The article, which comprises the cured silicone (formed from the curable silicone composition) adhered to the substrate, may have varying dimensions, including relativethicknesses of the cured silicone and the substrate. The cured silicone has a thickness that may vary depending upon its end use application. For example, for a release coating, the cured silicone may have a thickness of greater than 0 to 4,000 pm, alternatively greater than 0 to 3,000 pm, alternatively greater than 0 to 2,000 pm, alternatively greater than 0 to 1,000 pm, alternatively greater than 0 to 500 pm, alternatively greater than 0 to 250 pm. However, other thicknesses are contemplated, e.g. 0.1 to 200 pm. For example, the thickness of the fdm may be 0.2 to 175 pm; alternatively 0.5 to 150 pm; alternatively 0.75 to 100 pm; alternatively 1 to 75 pm; alternatively 2 to 60 pm; alternatively 3 to 50 pm; and alternatively 4 to 40 pm. Alternatively, when the substrate is plastic, the film may have a thickness of greater than 0 to 200, alternatively greater than 0 to 150 pm, and alternatively greater than 0 to 100 pm.

[0048] The article may be utilized in diverse end use applications. For example, the article may be utilized in coating applications, packaging applications, adhesive applications, fiber applications, fabric or textile applications, construction applications, transportation applications, electronics applications, or electrical applications. However, the curable composition may be utilized in other applications, e.g. in the preparation of electronic devices.

[0049] Alternatively, the article may be utilized as a release liner, e.g. for a tape or adhesive, including any pressure-sensitive adhesives, including acrylic resin-type pressure-sensitive adhesives, rubber-type pressure-sensitive adhesives, and silicone-type pressure-sensitive adhesives, as well as acrylic resin-type adhesives, synthetic rubber-type adhesives, silicone-type adhesives, epoxy resin-type adhesives, and polyurethane-type adhesives. Each major surface of the substrate may have a cured silicone disposed thereon for double sided tapes or adhesives.

[0050] The method of use of the curable silicone composition may further comprise: 3) treating the substrate before disposing the curable silicone composition on the substrate.Treating the substrate may be performed by any convenient means such as a plasma treatment or a corona discharge treatment. Alternatively, the substrate may be treated by applying a primer. In certain instances anchorage of the cured silicone may be improved if the substrate is treated before disposing the curable silicone composition thereon.

[0051] When the curable silicone composition includes a solvent, the method may further comprise: 4) removing solvent, which may be performed by any conventional means, such as heating at 50 °C to 100 °C for a time sufficient to remove all or a portion of the solvent. The method may further comprise 5) curing the curable silicone composition to form a cured silicone on a surface of the substrate. Curing may be performed by any conventional means such as heating at 100 °C to 200 °C.EXAMPLES

[0052] These examples are intended to illustrate the invention and should not be interpreted aslimiting the scope of the invention set forth in the claims. The starting materials in Table 1 were used in the examples herein.Table 1 - Starting Materials

[0053] In this Synthesis Example 1, a IL 3-neck flask was equipped with a condenser (air cooled) with a nitrogen sweep to a bubbler, a thermocouple, overhead stirring (glass rod with teflon paddle) and a septum. The glassware was purged with nitrogen (3 L / min) for 20 minutes. MH- 1109 (99.97 g) was then added to the flask followed by anhydrous toluene (49.97 g). Stirring was started (230 rpm) before addition of 0.324g of BCF catalyst solution (1% in toluene). Diphenyldisilanol (56.07g) was added in 4 portions over the course of ~1.5 hours maintaining the reaction temperature below 30 °C. The reaction mixture was stirred for an additional 1.5 hours after addition was complete. The resulting clear solution was then treated with 36 pL of phenyl acetylene before removal of volatiles via rotary evaporator (ramp to full vacuum, temperature ramp to 80 °C, held at 80 °C for ~lh). The resulting product was analyzed by LC-MS, H NMR and29Si NMR and found to contain an organohydrogensiloxanecomprising formula:each subscript n independently had an average value of 3 as the main component of the product.

[0054] In this Synthesis Example 2, a three-neck flask was charged with the product prepared in Synthesis Example 1 (85.2 g) and heated to 80 °C under N2 upon stirring. Karstedt’s catalyst(amount sufficient to provide 2 ppm of platinum) was added, followed by the gradual addition of allyl glycidyl ether (AGE) (24.8 g). The addition rate was controlled so that the reaction mixture temperature did not exceed 90 °C. After addition of AGE was complete, the reaction mixture was stirred at 80 °C under N2 for additional 1 hour before being cooled to room temperature. The resulting hydrosilylation reaction product was loaded with 1-ethynyl-l-cyclohexanol (0.17 g), stripped under vacuum, and characterized by]H,29Si, and13C NMRs and found to contain a functionalized organosiloxane comprising formulatwo instances of R8(one on each cyclic siloxane moiety) were each a propylglycidyl ether moiety and the remaining instances of R8were each H, and each subscript n independently had an average value of 3 as the main component of the stripped product.

[0055] In this Reference Example 3, a liquid silicone rubber composition was prepared. Samples of this composition were used as follows: In the comparative example (sample Cl), no adhesion promoter was added. In sample SEI, the product of Synthesis Example 1 comprisingthe organohydrogensiloxane shown above was added to the liquid silicone rubber composition. In sample SE2, the product of Synthesis Example 2 comprising the functionalized organosiloxane shown above was added to the liquid silicone rubber composition in the same amount. Samples Cl, SEI, and SE2 were each coated on two different substrates and cured to form articles. A 90° peel adhesion test (floating roller method) was performed according to ASTM 3167 on each article. The results are shown below in Table 2.Table 2 - Peel Strength (N / mm) on Different Substrates (PBT and PA-66)

[0056] The results in Table 2 showed that the organohydrogensiloxane prepared in Synthesis Example 1 and the functionalized organosiloxane (functionalized with glycidyl ether groups) of Synthesis Example 2 each improved adhesion of a silicone rubber to the substrates tested. Both are suitable for use as adhesion promoters in curable silicone compositions, such as LSR compositions. The epoxy-functional organosiloxane of Synthesis Example 2 provided the best (strongest) adhesion to both substrates under the conditions tested.Test Methods

[0057] The following test methods were used in the Examples above.LC-MSSample Preparation

[0058] The samples were dissolved in tetrahydrofuran (THF) to 0.1 wt% and injected onto the UPLC (ultra-high pressure liquid chromatography) system. A binary gradient separation was developed to separate the majority of individual components present in the samples. Exact mass electrospray ionization Q-TOF-MS was used to identify the unknown compounds of interest.Instrumental Conditions

[0059] UPLC ConditionsInstrument: Agilent 1290 UPLC SystemColumn: Agilent ProShell Cis UPLC column, 2.7 pm, 3.0x50 mmColumn temperature: 40 °CSolvent A: 0.1% formic acid, 0.1% NFLiOac in 18 MQ H2OSolvent B: Fisher HPLC Grade THFFlow rate: 0.60 mL / minInjection volume: 0.25 pLBinary gradient:Time, min %B0.0 5030 7030.05 10034 100Post equilibration time: 5 min MS Conditions

[0060] Instrument: Agilent 6538 Quadrupole / Time-of-Flight (Q-TOF) Tandem Mass SpectrometerIon source: Dual electrospray ionization Mass Range: 110-2000 m / z Drying gas temp: 325 °C Drying gas flow rate: 8 L / min Nebulizer pressure: 30 psi Mode: Positive ionCapillary voltage: 3500 VFragmentor voltage: 175 VSkimmer voltage: 65 V

[0061] NMR. Proton ( ' H) nuclear magnetic resonance (NMR) spectra were recorded on an Agilent 500-MR NMR spectrometer operating at 500 MHz. Carbon (13C) and silicon (29Si) NMR spectra were recorded on an Agilent 500 MHz DD2 system with a 16mm silicon free AutoZ probe. Peak frequencies are recorded in ppm.]H samples were run with 100 pL sample in 1 mL deuterated chloroform (CDCL), while29Si and13C samples were run with 2 mL sample in 3 mL deuterated chloroform with Cr(acac)3. Spectra were analyzed using Mnova NMR software.Industrial Applicability

[0062] Without wishing to be bound by theory, it is thought that as the degree of polymerization of a linear diorganosiloxane decreases, especially with hydroxyl- or alkoxyterminated polydiorganosiloxanes such as those disclosed in U.S. Patent Application Publications 2022-0025125, 2023-0151156, or 2023-0151157, certain synthetic methods will cease to work efficiently (for silane diols) for one or more of the following reasons: solubility change, catalyst activity change, and steric and electronic effects on reactivities of alkenyl (e.g., vinyl), alkoxy, or hydroxy groups connected to the silicon atoms in the diorganosiloxane. As a result, siloxane structures having two cyclic SiH containing endblocks linked by one aromatic siloxy unit have not been successfully synthesized using the methods described above. Definitions and Usage of Terms

[0063] Abbreviations used in the specification have the definitions in Table 3, below.Table 3 - Abbreviations

[0064] All amounts, ratios, and percentages are by weight unless otherwise indicated. The amounts of all starting materials in a composition total 100% by weight. The SUMMARY and ABSTRACT are hereby incorporated by reference. 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. The disclosure of ranges includes the range itself and also anything subsumed therein, as well as endpoints. For example, disclosure of a range of 2 to 4 includes not only the range of 2 to 4, but also 2, 3, and 4 individually, as well as any other number subsumed in the range. Furthermore, disclosure of a range of, for example, 2 to 4 includes the subsets of, for example, > 2 to < 4, 2.1 to 3.5, 2.3 to 3.4, 2.5 to 3.7, and 2.5 to 3, as well as any other subset subsumed in the range. Similarly, the disclosure of Markush groups includes the entire group and also any individual members and subgroups subsumed therein. For example, disclosure of the Markush group an acrylate group, an alcohol group, an alkoxy group, an epoxy group, an isocyanate group, a methacrylate group, and a urethane group, includes the member epoxy individually; the subgroup epoxy, acrylate, and methacrylate; and any other individual member and subgroup subsumed therein.Embodiments of the Invention

[0065] In a first embodiment, an organohydrogensiloxane comprises formula:each subscript n independently has an average value of 2 to 4, and each R is an independently selected alkyl group of 1 to 4 carbon atoms.

[0066] In a second embodiment, in the organohydrogensiloxane of the first embodiment, each subscript n has an average value of > 2 to 4, and each R is methyl or ethyl.

[0067] In a third embodiment, in the organohydrogensiloxane of the second embodiment, each subscript n has an average value of 2.5 to 3, and each R is methyl.

[0068] In a fourth embodiment, the organohydrogensiloxane of any one of the first to third embodiments is free of platinum group metal catalysts.

[0069] In a fifth embodiment, a method for preparing the organohydrogensiloxane of any one of the first to third embodiments comprises:1) combining starting materials comprisingA) tris(pentafluorophenyl)borane;B) diphenyl- silane diol of formulaC) a cyclic polyorganohydrogensiloxane of formula ( RHS1O2 / 2 )v, where each R is methyl, and subscript v has an average value of 4 to 6; andoptionally D) a solvent; thereby preparing a reaction product comprising the organohydrogensiloxane and a by-product comprising H2.

[0070] In a sixth embodiment, in the method of the fourth embodiment, the method further comprises: 2) during and / or after step 1), removing the H2 generated during formation of the organohydrogensiloxane.

[0071] Tn a seventh embodiment, in the method of any one of the first to fifth embodiments, the method further comprises: 3) neutralizing residual A) Lewis acid catalyst in the organohydrogensiloxane.

[0072] In an eighth embodiment, an epoxy-functional organosiloxane comprises formula:each subscript n independently has an average value of 2 to 4, each R is an independently selected alkyl group of 1 to 4 carbon atoms, and each R8is independently selected from the group consisting of H and an epoxy- functional group, with the proviso that at least two instances of R8per molecule are the epoxyfunctional group.

[0073] In a ninth embodiment, in the epoxy-functional organosiloxane of the eighth embodiment, each subscript n independently has an average value of > 2 to 4, each R is methyl or ethyl, and two instances of R8per molecule represent epoxy- functional groups and all other instances of R8represent H.

[0074] In a tenth embodiment, in the functionalized organosiloxane of the eighth embodiment or the ninth embodiment, each subscript n has an average value of 2.5 to 3, each R is methyl, and one instance of R8on each ring is an epoxy-functional group and each remaining instance of R8is H.

[0075] Tn an eleventh embodiment, a method for preparing the epoxy-functional organosiloxane of any one of the eighth to tenth embodiments comprises:1) combining, under conditions to effect dehydrogenative condensation reaction, starting materials comprisingA) tris(pentafluorophenyl)borane;B) diphenyl- silane diol of formulaC) a cyclic polyorganohydrogensiloxane of formula (RHSiO2 / 2)v, where each R is methyl, and subscript v has an average value of 4 to 6; and optionally D) a solvent; thereby preparing a dehydrogenative condensation reaction product comprising the organohydrogensiloxane and a by-product comprising H2; optoinally 2) during and / or after step 1), removing the H2 generated during formation of the organohydrogensiloxane; optionally 3) neutralizing residual A) Lewis acid catalyst in the organohydrogensiloxane; optionally 4) recovering the organohydrogensiloxane; i) combining, under conditions to effect hydrosilylation reaction, starting materials comprising the dehydrogenative condensation reaction product or a) the organohydrogensiloxane, b) a hydrosilylation reaction catalyst, and c) a reactive species having an average, per molecule at least one aliphatically unsaturated group capable of undergoing an addition reaction with a silicon bonded hydrogen atom of starting material a) and further comprising one or more epoxy-functional groups; and optionally d) a solvent; thereby preparing a hydrosilylation reaction product comprising the functionalized organosiloxane.

[0076] Tn a twelfth embodiment, in the method of the eleventh embodiment, the reactive species comprises a silane of formula R4ySiR5(4-y), where subscript y is 1 to 3, each R4is the aliphatically unsaturated group capable of undergoing addition reaction, and each R5is anepoxy-functional group.

[0077] In a thirteenth embodiment, in the method of the eleventh embodiment, the reactive species comprises an organic compound of formula R6R7, where R6is the aliphatically unsaturated group capable of undergoing addition reaction, and each R7is an epoxy-functional group.

[0078] Tn a fourteenth embodiment, in the method of the thirteenth embodiment, the reactive species is allyl glycidyl ether.

[0079] In a fifteenth embodiment, the organohydrogensiloxane of any one of the first to fourth embodiments or the functionalized organosiloxane of any one of the eighth to tenth embodiments is used as an adhesion promoter in a liquid silicone rubber composition.

[0080] In a sixteenth embodiment, a method for making an article comprises:1 ) adding the organohydrogensiloxane of any one of the first to fourth embodiments or the functionalized organosiloxane of any one of the eighth to tenth embodiments to a liquid silicone rubber composition, optionally 2 ) treating a surface of a substrate,3 ) disposing the liquid silicone rubber composition prepared in step 1 ) on the surface of the substrate, and4 ) curing the liquid silicone rubber composition.

[0081] In a seventeenth embodiment, the organohydrogensiloxane of any one of the first to fourth embodiments is used as a crosslinker or a co-crosslinker in a silicone release coating composition.

[0082] In an eighteenth embodiment, a method for making a silicone release coating comprises: i) adding the organohydrogensiloxane of any one of the first to fourth embodiments to a silicone release coating composition, optionally ii) treating a surface of a substrate, iii) disposing the silicone release coating composition prepared in step i) on the surface of the substrate, and iv) curing the silicone release coating composition.

Claims

CLAIMS:

1. An organosiloxane comprises formula:each subscript n independently has an average value of 2 to 18, each R is an independently selected monovalent hydrocarbyl group;R1is a monovalent hydrocarbyl group selected from an alkyl group and an aromatic group,R2is a monovalent aromatic group, and each R8is independently selected from the group consisting of H and a functional group containing a moiety selected from the group consisting of an acrylate group, an alcohol group, an alkoxy group, an epoxy group, an isocyanate group, a methacrylate group, and a urethane group; with the proviso that at least one instance of R8per molecule is the functional group.

2. The organosiloxane of claim 1, where each subscript n independently has an average value of 2 to 4, each R is methyl or ethyl;R1is selected from the group consisting of methyl, phenyl, tolyl, and xylyl;R2is selected from the group consisting of phenyl, tolyl, and xylyl; and an average of two instances of R8per molecule are the functional group and all remaining instances of R8are H.

3. The organosiloxane of claim 2, where each subscript n has an average value of 2.5 to 3, each R is methyl,R1is methyl or phenyl,R2is phenyl, and each R8is selected from H and an epoxy-functional group.

4. A method for making the organosiloxane of any one of claims 1 to 3, wherein the method comprises:1) combining, under conditions to effect dehydrogenative condensation reaction, starting materials comprisingA) Lewis acid catalyst comprising a fluorinated arylborane;R1HO - Si - OHB) an aromatic silane diol of formula R2, whereR1is a monovalent hydrocarbyl group selected from an alkyl group and an aromatic group, andR2is a monovalent aromatic group;C) a cyclic polyorganohydrogensiloxane of unit formula (RHSiO2 / 2)n, where subscript n has an average value of 2 to 18, and each R is an independently selected monovalent hydrocarbyl group; and optionally D) a solvent; thereby preparing a dehydrogenative condensation reaction product comprising an organohydrogensiloxane and a by-product comprising H2; optionally 2) during and / or after step 1), removing H2 generated during formation of the organohydrogensiloxane; and optionally 3) neutralizing residual Lewis acid catalyst in the dehydrogenative condensation reaction product; optionally 4) removing a particulate after step 3), when step 3) is present; and i) combining, under conditions to effect hydrosilylation reaction, starting materials comprising the dehydrogenative condensation reaction product or a) the organohydrogensiloxane, b) a hydrosilylation reaction catalyst, and c) a reactive species having an average, per molecule at least one aliphatically unsaturated group capable of undergoing an addition reaction with a silicon bonded hydrogen atom of starting material a) and further comprising a moiety comprising a functional group; thereby preparing a hydrosilylation reaction product comprising the organosiloxane; optionally ii) adding a hydrosilylation reaction inhibitor to the hydrosilylation reaction product; and optionally iii) recovering the organosiloxane.

5. The method of claim 4, where c) the reactive species comprises a silane of formula R4ySiR5(4-y), where subscript y is 1 to 3, each R4is the aliphatically unsaturated group capable of undergoing an addition reaction, and each R5is independently an organic group comprising a functional moiety selected from an acrylate group, an alcohol group, an alkoxy group, an epoxy group, an isocyanate group, a methacrylate group, or a urethane group.

6. The method of claim 4, where c) the reactive species comprises an organic compound of formula R6R7, where each R6is the aliphatically unsaturated group capable of undergoing an addition reaction, andR7is an organic group comprising a functional moiety selected from an acrylate group, an alcohol group, an alkoxy group, an epoxy group, an isocyanate group, a methacrylate group, and a urethane group.

7. The method of claim 6, where R6is an alkenyl group and R7is an epoxy-functional group.

8. The method of claim 6 or claim 7, where the reactive species comprises allyl glycidyl ether.

9. The method of any one of claims 4 to 8, where A) the Lewis acid comprises tris(pentafluorophenyl)borane.

10. The method of any one of claims 4 to 9, where step iii) is present, and the hydrosilylation reaction inhibitor comprises an acetylenic alcohol.

11. An organohydrogensiloxane comprising formula:each subscript n independently has an average value of 2 to 18, each R is an independently selected monovalent hydrocarbyl group;R1is a monovalent hydrocarbyl group selected from an alkyl group and an aromatic group, andR2is a monovalent aromatic group.

12. The organohydrogensiloxane of claim 1 1 , where each subscript n independently has an average value of 2 to 4, each R is methyl or ethyl;R1is selected from the group consisting of methyl, phenyl, tolyl, and xylyl; andR2is selected from the group consisting of phenyl, tolyl, and xylyl.

13. The organosiloxane of claim 12, where each subscript n has an average value of 2.5 to 3, each R is methyl,R1is methyl or phenyl, andR2is phenyl.

14. A method for making the organohydrogensiloxane of any one of claims 11 to 13, wherein the method comprises:1) combining, under conditions to effect dehydrogenative condensation reaction, starting materials comprisingA) Lewis acid catalyst comprising a fluorinated arylborane;R1HO - Si - OH2B) an aromatic silane diol of formula R , whereR1is a monovalent hydrocarbyl group selected from an alkyl group and an aromatic group, andR2is a monovalent aromatic group;C) a cyclic polyorganohydrogensiloxane of unit formula (RHSiO2 / 2)n, where subscript n has an average value of 2 to 18, and each R is an independently selected monovalent hydrocarbyl group; and optionally D) a solvent; thereby preparing a dehydrogenative condensation reaction product comprising an organohydrogensiloxane and a by-product comprising H2; optionally 2) during and / or after step 1), removing the H2generated during formation of the organohydrogensiloxane; and optionally 3) neutralizing residual boron containing Lewis acid in the organohydrogensiloxane; and optionally 4) removing a particulate after step 3), when step 3) is present.

15. Use of the organohydrogensiloxane of any one of claims 11 to 13, as a crosslinker or a cocrosslinker in a silicone release coating composition.

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