Organosiloxane and methods for the preparation and use thereof

Abstract

An organosiloxane has formula (I), wherein each subscript n independently has an average value of 2 to 18, each R1 is an independently selected monovalent hydrocarbyl group; each R is independently selected from H or a functional group containing a 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; each D is an independently selected divalent hydrocarbyl group of 2 to 6 carbon atoms; and L an organosilicon linker. The organosiloxane is useful in various application such 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 benefits of U.S. Provisional Patent Application No. 63 / 727696 filed on 4 December 2024 and U.S. Provisional Patent Application No. 63 / 663204 filed on 24 June 2024 under 35 U.S.C. §1 19 (e). U.S. Provisional Patent Application No. 63 / 727696 and U.S. Provisional Patent Application No. 63 / 663204 are 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 an aryl-functional organosilicon moiety. 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. US Patent 7429636 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] US Patent 9593209 discloses multifunctional end-blocked siloxanes, how to make them, and some of the challenges with making them. Synthesis of the multifunctional end- blocked siloxanes involves a hydrosilylation reaction between a vinyl-endblocked linear polyorganosiloxane with a cyclic, linear or branched silicone containing silylhydride (SiH) groups to form a “dumb-bell” intermediate. A challenge with this synthesis is that if allowed to sit too long with a platinum hydrosilylation reaction catalyst after the reaction is done, or if purified at elevated temeprature by distillation or other stripping step with a Pt hydrosilylation catalyst present, unsdesirable gelling of the dumb-bell intermediate can occur. However, despite the challenges with Pt, it is desirable to use a Pt hydrosilylation catalyst to make the dumb-bell intermediate because Pt catalysts are some of the most effective for efficient hydrosilylation reactions.

[0005] 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

[0006] An organosiloxane, and methods for preparation and use of the organosiloxane, are provided. The organosiloxane comprises formula:independently has an average value of 2 to 18; each R1is an independently selected monovalent hydrocarbyl group; each R is independently selected from the group consisting of H and a functional moiety containing a reactive group 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; each D is an independently selected divalent hydrocarbyl group; and L is a divalent organosilicon linking moiety. The method for preparing the organosiloxane comprises hydrosilylation reaction of an alkenyl-functional siloxane and a cyclic polyorganohydrogensiloxane in the presence of a platinum hydrosilylation reaction catalyst.DETAILED DESCRIPTION

[0007] The organosiloxane introduced above may have silyl hydride functionality, i.e., the organosiloxane may be an organohydrogensiloxane when each R is a hydrogen atom (H). A method for preparing a first hydrosilylation reaction product comprising the organohydrogensiloxane comprises: 1) combining, under conditions to effect a first hydrosilylation reaction, starting materials comprising: A) a hydrosilylation reaction catalyst; B) an alkenyl-functional siloxane; and C) a cyclic polyorganohydrogensiloxane; thereby preparing the first hydrosilylation reaction product comprising the organohydrogensiloxane. The starting materials used the method may optionally further comprise an additional starting material selected from the group consisting of D) a solvent, E) a hydrosilylation reaction inhibitor, F) athiuram disulfide compound, and a combination thereof.

[0008] The first hydrosilylation reaction in step 1) may be carried out batchwise, semi-batch or continuous in any suitable equipment, such as a jacketed reactor with agitation means such as an impeller or baffles. Step 1) may be performed with mixing and heating, e.g. , at a temperature of 50 °C to 100 °C, alternatively 60 °C to 90 °C, and alternatively 70 °C to 80 °C. The starting materials used in step 1) may be combined by any convenient means. For example, one or more of the starting materials, such as A) the hydrosilylation reaction catalyst may be dissolved in D) the solvent. The starting materials may be combined in any order. Alternatively, to minimize potential for generation of hydrogen, A) the hydrosilylation reaction catalyst may be kept separate from C) the cyclic polyorganohydrogensiloxane until reaction begins. For example, A) the hydrosilylation reaction catalyst, B) the alkenyl-functional siloxane, and optionally all or a portion of D) the solvent may be combined and the resulting mixture metered into a reactor containing C) the cyclic polyorganohydrogensiloxane or a mixture of C) the cyclic polyorganohydrogensiloxane and all or a portion of D) the solvent. Starting material E) the hydrosilylation reaction inhibitor may be added to one or both of the above mixtures to control hydrosilylation reaction rate.

[0009] The method for preparing the first hydrosilylation reaction product comprising the organohydrogensiloxane may optionally further comprise one or more additional steps. For example, the method may optionally further comprise, before step 1), treating (e.g., by stripping or distilling) one or more of the starting materials. For example, starting material B) and / or starting material C) may be treated to remove water (drying) or other impurities before step 1). Alternatively, the method may further comprise 2) purifying the organohydrogensiloxane produced during step 1). For example, after formation of first hydrosilylation reaction product comprising the organohydrogensiloxane, purifying may be performed by any convenient means, such as stripping and / or distillation with heating and optionally reduced pressure. The method may optionally further comprise step 3): adding F) the thiuram disulfide compound. All or a portion of the thiuram disulfide compound may be added during step 1). Alternatively, F) the thiuram disulfide compound may be added during step 1), for example, when the first hydrosilylation reaction will be carried out in the presence of the Pt- Thiuram complex at temperatures such as 80 °C to 90 °C. Alternatively, all or a portion of F) the thiuram disulfide compound may be added to the first hydrosilylation reaction product comprising the organohydrogensiloxane after step 1) and / or to the organohydrogensiloxane after step 1) or after step 2), when step 2) is present. Alternatively, the thiuram disulfide compound may be added to the first hydrosilylation reaction product after step 1) and before step 2) (e.g., to minimize potential for gelation of the organohydrogensiloxane during storage or purification in step 2),when step 2) is present. The thiuram disulfide compound may optionally be delivered in a solvent, such as starting material D). When step 1) uses a platinum catalyst for starting material A), then step 3) is present, and F) the thiuram disulfide compound is present in the first hydrosilylation reaction product. Without wishing to be bound by theory, it is thought that the selection and amount of F) the thiuram disulfide compound, and when it is added during the method depends on various factors including the selection and amounts of starting materials A) and B).

[0010] Hydrosilylation reaction catalysts suitable for starting material A) in the method for preparing the first hydrosilylation reaction product comprising the organohydrogensiloxane are known in the art and are commercially available. Hydrosilylation reaction catalysts include platinum group metal catalyst, e.g., the hydrosilylation catalyst 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, chloroplatinic acid (Speier’s Catalyst), hexachloroplatinic acid hexahydrate, platinum dichloride, and complexes of said compounds with organopolysiloxanes or platinum compounds microencapsulated in a matrix or coreshell type structure. Complexes of platinum with alkenyl-functional 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. Exemplary hydrosilylation reaction catalysts are described in US Patent 12195593 and the references cited therein. Alternatively, in step 1) of the method, the platinum group metal may be platinum. 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). Alternatively, in step 1), the amount of platinum may be up to 5 ppm, alternatively < 5 ppm, alternatively up to 2 ppm, and alternatively < 2ppm; while at the same time, the amount of platinum is > 0 ppm, alternatively at least 1 ppm, each based on combined weights of starting materials A), B), and C). Without wishing to be bound by theory, it is thought that using > 0 ppm to 5 ppm, alternatively 1 ppm to 5 ppm, of platinum may minimize side reactions such as crosslinking and / or gelation, particularly when the alkenyl-functional siloxane has a short chain, e.g., wherein subscript x is 0 or 1 in general formula B-l), below.

[0011] Starting material B) used in the method described above is an alkenyl-functional siloxane. The alkenyl-functional siloxane may have general formula B-l):, wherein subscript x is an integer with a value of 0 to1,000; each RV1is an independently selected alkenyl group, and each RMis an independently selected monovalent hydrocarbyl group with 1 to 20 carbon atoms. Suitable alkenyl groups for RV1may have 2 to 6 carbon atoms and are exemplified by vinyl, allyl, and hexenyl; alternatively vinyl. Suitable monovalent hydrocarbyl groups for RMmay be free of aliphatic unsaturation and may be selected from alkyl groups and aromatic groups. Suitable alkyl groups for RMmay have 1 to 20 carbon atoms. Suitable alkyl groups may be linear or branched and include methyl, ethyl, and propyl (including n-propyl and isopropyl), alternatively methyl. The aromatic group for RMmay have 6 to 20 carbon atoms. The aromatic groups may be monocyclic or polycyclic, alternatively monocyclic. Examples of suitable aromatic groups include phenyl, tolyl, xylyl, 1- phenylethyl, 2-phenylethyl, 2-methyl-2-phenylethyl, 3-phenylpropyl, 4-phenylbutyl, benzyl, styryl, naphthyl and anthracenyl. Alternatively, the aromatic group may be selected from the group consisting of phenyl, tolyl and xylyl. Alternatively, the aromatic group may be selected from the group consisting of phenyl and tolyl. Alternatively, the aromatic group may be phenyl. Alternatively, each RMmay be independently selected from the group consisting of methyl and phenyl. Alternatively, subscript x may be 0 or more, alternatively 1 or more, alternatively 2 or more, alternatively 3 or more, alternatively 4 or more, alternatively 5 or more, alternativley 6 or more, alternatively 7 or more, alternatively 8 or more, alternatively 9 or more, alternatively 10 or more, alternatively 12 or more, alternatively 14 or more, alternatively 16 or more, alternatively 18 or more, alternatively 20 or more, alternatively 25 or more, alternatively 50 or more, alternatively 75 or more, alternatively 80 or more, alternatively 100 or more; while at the same time, subscript x may be 1,000 or less, alternatively 900 or less, alternatively 800 or less, alternatively 700 or less, alternatively 600 or less, alternatively 500 or less, alternatively 400 or less, alternatively 300 or less, alternatively 200 or less, alternatively 100 or less, alternatively 80 or less, alternatively 60 or less, alternatively 40 or less, alternatively 30 or less, and alternatively 20 or less. Alternatively, subscript x may be 0 to 100, alternatively 0 to 80, and alternatively 0 to 25. Alternatively, subscript x may be 0 or 1. Alternatively, subscript x may be 0.

[0012] Methods of preparing alkenyl-functional siloxanes described above for starting material B), such as hydrolysis and condensation of the corresponding organohalosilanes and oligomers or equilibration of cyclic polydiorganosiloxanes, are known in the art, see for example US Patent Application Publication 2023-0242711 and the references cited therein. Examples of such alkenyl-functional are commercially available from, e.g. Gelest Inc. of Morrisville,Pennsylvania, USA under the tradenames DMS-V05, DMS-V21, DMS-V22, DMS-V25, DMS- V-31, DMS-V35, DMS-V42, DMS-V46, DMS-V51, PDV-0525, PDV-1641, PDV-1631, PDV- 1625, PDV-0325, and PDV-0541.

[0013] Alternatively, B) the alkenyl-functional siloxane may be selected from the group consistingwherein each RA|is an independently selected monovalent aromatic group, each R3is an independently selected alkyl group, and each RV1is an independently selected alkenyl group, each as described and exemplified above. Alternatively, each RA|may be phenyl. Alternatively, each R3may be methyl. Examples of alkenyl-functional siloxanes for starting material B) include l,5-divinyl-l,l,5,5-tetramethyl-3,3-diphenyltrisiloxane with CAS #18586-22-6, which is available from various sources, such as TCI America and Cymit Quimica S.L. of Barcelona, Spain; and l,3-divinyl-l,3-dimethyl-l,3-diphenyldisiloxane with CAS #2627-97-6 and which is available from various sources such as Alpha Chemistry of Holbrook, New York, USA.

[0014] Starting material C) for the method described herein is a cyclic polyorganohydrogensiloxane of formula C-l): (R1HSiO2 / 2)v, where subscript v has an average value of 4 to 20, and each R1is an independently selected monovalent hydrocarbyl group, alternatively an alkyl group. Alternatively, subscript v may have an average value of at least 4, alternatively at least 5, and alternatively at least 6; while at the same time subscript v may have a value up to 20, alternatively up to 15, alternatively up to 12, alternatively up to 10, alternatively up to 8, and alternatively up to 6. Alternatively, subscript v may have an average value of 4 to 10, and alternatively 4 to 8. Alternatively, subscript v may have an average value of 4 to 6, alternatively 4 to 5, alternatively > 4 to 5, and alternatively 4.5 to 5. In formula C-l), R1may be an alkyl group of 1 to 6 carbon atoms. Alternatively, each R1may be independently selected from methyl, ethyl, or propyl. Alternatively, each R1may be methyl.

[0015] Examples of suitable cyclic polyorganohydrogensiloxanes for starting material C) include tetramethylcyclotetrasiloxane (with CAS No. 2370-88-9), pentamethylcyclopentasiloxane (with CAS No. 6166-86-5), hexamethylcyclohexasiloxane (with CAS No. 6166-87-6), and combinations of two or more thereof. Suitable cyclic polyorganohydrogensiloxanes are known in the art and are commercially available, e.g., DOWSIL™ MH- 1109 Fluid from Dow Silicones Corporation of Midland, Michigan, USA and SIP6718.0 and SIT7530.0 both from Gelest.

[0016] The amounts of B) the alkenyl-functional siloxane and C) the cyclicpolyorganohydrogensiloxane may be in the method used in amounts such that the molar ratio of cyclic polyorganohydrogensiloxane : alkenyl-functional siloxane, C:B, is > 2:1, alternatively > 3:1, alternatively > 4:1, and 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 alkenyl in starting material B) (SiH : Vi mole ratio) is 10: 1 to 40: 1 , alternatively 10:1 to 20:1 , and alternatively 10:1 to 15:1. Alternatively, SiH : Vi ratio may be at least 4:1, alternatively at least 6:1, alternatively at least 8:1, alternatively 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 : Vi ratio may be up to 180 : 1, alternatively up to 90: 1; alternatively up to 50:1. Alternatively, the SiH : Vi ratio may be 4:1 to 8:1, and alternatively 4:1 to 6:1.

[0017] A solvent may be used in the method described herein. The solvent may facilitate introduction of certain starting materials, such as A) the hydrosilylation reaction catalyst and / or F) the thiuram disulfide. Solvents used herein are those that help fluidize the 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 A) the hydrosilylation reaction catalyst, B) the alkenyl-functional siloxane, and C) the cyclic polyorganohydrogensiloxane.

[0020] Starting material E) is a hydrosilylation reaction inhibitor that may be used in the method for making the first hydrosilylation reaction product comprising the organohydrogensiloxane. 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 control hydrosilylation reaction rate because hydrosilylation reaction is exothermic. The amount of inhibitor selected depends on various factors including the type and amount of hydrosilylation reaction catalyst and inhibitor selected, however, if used, the amount may besufficient to provide 1 ppm to 1,000 ppm of the platinum group metal based on combined weights of reactants (e.g., B) the alkenyl-functional siloxane and C) the cyclic polyorganohydrogensiloxane). Suitable hydrosilylation reaction inhibitors are known in the art and are described, for example, described as ingredient i) in US Patent 9593209 at col. 15, line 35 to col. 16, line 17. Alternatively, the first hydrosilylation reaction may be performed in a semi-batch or continuous process, such that a hydrosilylation reaction inhibitor described herein as starting material E) is not required, for example the exothermic hydrosilylation reaction can be controlled by the order of addition of the starting materials, e.g., by metering starting materials B) and / or C).

[0021] Starting material F) is a thiuram disulfide compound (thiuram disulfide). Without wishing to be bound by theory, it is thought that the thiuram disulfide will complex with the platinum from A) the hydrosilylation reaction catalyst (when a platinum catalyst is used) to form an inhibibited platinum at temperatures of 120 °C and lower, alternatively 100 °C and lower, alternatively 80 °C and lower, such that the inhibited platinum does not catalyze a hydrosilylation reaction, and such that side reactions such as gelation of the organohydrogensiloxane are minimized or avoided during purification, storage, or both, as described herein. The thiuram disulfide may have formula F-l):F-l), wherein RH, RN, RJ, and RKare each an independently selected monovalent hydrocarbyl group having 1 to 20 carbon atoms, which may be saturated or unsaturated; a heteroatom-containing monovalent hydrocarbyl group having 1 to 20 carbon atoms, which may be saturated or unsaturated; or combinations thereof. Suitable heteroatoms may include, for example, an oxygen atom. RHand RNgroups may combine to form one or more carbocyclic groups having 4 to 20 carbon atoms. RJand RKgroups may combine to form one or more carbocyclic groups having 4 to 20 carbon atoms.

[0022] In formula F-l), RH, RN, RJ, and RKcan be the same or different, and alternatively, these groups may be the same. Alternatively R11, RN, RJ, and RKmay be each independently selected from an alkyl group having 1 to 20 carbon atoms, alternatively 1 to 12, alternatively 1 to 6, alternatively 1 to 4, or alternatively 1 to 2 carbon atoms; an aromatic group having 6 to 20 carbon atoms, such as phenyl or benzyl; or combinations thereof. Alternatively, RH, RN, RJ, and RKare each independently selected alkyl groups. Alternatively, RH, RN, RJ, and RKare each independently selected from methyl, iso-butyl, n-butyl, or combinations thereof.

[0023] Specific examples of suitable thiuram disulfides include tetrabenzylthiuram disulfide (with CAS No. 10591-85-2), tetramethylthiuram disulfide (with CAS No. 137-26-8),tetraethylthiuram disulfide (with CAS No. 97-77-8), tetra(iso-propyl)thiuram disulfide, tetra(iso- butyl)thiuram disulfide (with CAS No. 3064-73-1), and tetra(n-butyl)thiuram disulfide (with CAS No. 1634-02-2), all of which are commercially available from various sources such as Sigma- Aldrich, Inc., TCI America, Fischer Scientific, or Cymit Quimica S.L. Alternatively, the thiuram disulfide may be selected from tetramethylthiuram disulfide, tetra(n-butyl)thiuram disulfide, or mixtures thereof.

[0024] The thiuram disulfide may be optionally diluted in a solvent before use in the method. The solvent may be any material that can dissolve the thiuram disulfide, as described and exemplified above for starting material D). Alternatively, the solvent for the thiuram disulfide may be selected from aromatic hydrocarbons such as benzene, halogenated hydrocarbons, ethers, or mixtures thereof. Without wishing to be bound by theory, it is thought that it may be desirable to use as little solvent as possible to facilitate dissolving the thiuram disulfide and, if desired, to later remove the solvent, e.g., by evaporation, distillation, and / or stripping. Examples of suitable solvents may include halogenated hydrocarbons such as dichloromethane, chloroform (CHCh), and / or tetrachloromethane. The solvent may be used in an amount of 0. 1% to 5% by weight based on the weight of the thiuram disulfide.

[0025] The thiuram disulfide compound may be added in an amount such that the molar ratio of the thiuram disulfide to platinum in the hydrosilylation reaction catalyst (F / Pt ratio) may range from 0.9 to 100. Alternatively, this molar ratio may be 1 or higher, alternatively greater than 1, alternatively 1.1 or higher, and alternatively 1.2 or higher, alternatively 2 or higher, alternatively 3 or higher, alternatively 4 or higher, alternatively 5 or higher, alternatively 6 or higher, alternatively 7 or higher, alternatively 8 or higher, a Iternatively 9 or higher; while at the same time this ratio may be 100 or lower, alternatively 75 or lower, alternatively 50 or lower, alternatively 40 or lower, alternatively 30 or lower, alternatively 20 or lower, alternatively 10 or lower, alternatively 5 or lower, alternatively 3 or lower, alternatively 2 or lower, and alternatively 1.2 or lower. Alternatively, this F / Pt ratio may be 1 to 10, alternatively 1 to 5, alternatively 2 to 5, alternatively 2 to 3.5, alternatively 1 to 2, and alternatively, 1 to 1.2. Alternatively, at low platinum concentration (e.g., > 0 ppm to 5 ppm based on combined weights of starting materials A), B), and C) described above), the F / Pt ratio may be 3 to 3.5, and this may allow for higher purification (e.g., stripping) temperatures. Without wishing to be bound by theory, it is thought that the Pt-thiuram complex is stable at temperatures below 120 °C, alternatively 115 °C or below, and alternatively 110 °C or below. Therefore, stripping under conditions of 95 °C at 0 - 3 mbar wherein the Pt-Thiuram complex is stable can be performed while gelation is avoided or minimized.

[0026] The first hydrosilylation reaction product of the method described above comprises a) the organohydrogensiloxane. This reaction product may further comprise unreacted starting materials (e.g., unreacted B) alkenyl-functional siloxane or unreacted C) cyclicpolyorganohydrogensiloxane, when one or the other is used in molar excess), residual A) hydrosilylation reaction catalyst, and when used D) the solvent, E) the hydrosilylation reaction inhibitor, and / or F) the thiuram disulfide compound, at least a portion of which may be complexed with the platinum from A) the hydrosilylation reaction catalyst. 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 R1, D, and L are 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.

[0027] Alternatively, the organohydrogensiloxane may have formula a-2):R3, RAr, and subscript n are as described above. Alternatively, the organohydrogensiloxane may have formula a-3):where each subscript n independently has an average value of 4 to 6, and Ph means phenyl.

[0028] Alternatively, the organohydrogensiloxane may have formula a-4):and subscript n are as described above. Alternatively, the organohydrogensiloxane may haveeach subscript n independently has an average value of 4 to 6, and Ph means phenyl.

[0029] 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.

[0030] The method described above may further comprise functionalizing the above-described a) organohydrogensiloxane to form a’ ) a functionalized organosiloxane. The method for functionalizing a) the organohydrogensiloxane comprises: i) practicing the method comprising step 1), and optionally one or more of the additional steps, described above to prepare the first hydrosilylation reaction product comprising a) the organohydrogensiloxane described above, and ii) combining, under conditions to effect a second hydrosilylation reaction, starting materials comprising the first hydrosilylation reaction product, or a) the organohydrogensiloxane, as described above; optionally 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 second hydrosilylation reaction product comprising a’) the functionalized organosiloxane.

[0031] Briefly stated, this method may be performed by modifying the method described in US Patent 9593209. The first hydrosilylation reaction product or a) the organohydrogensiloxanedescribed hereinabove may be combined with the reactive species and optionally the hydrosilylation reaction catalyst (described as components c) and d), respectively) in the amounts and under conditions described in US Patent 9593209 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.

[0032] In the method to form a’) the functionalized organosiloxane described herein, the hydrosilylation reaction may be performed by optionally dissolving or dispersing b) the hydrosilylation reaction catalyst (as described above for starting material A)) 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. The same reactor used to prepare the first hydrosilylation reaction product may be used herein to prepare the second hydrosilylation reaction product comprising a’) the functionalized organosiloxane. Alternatively, a different reactor may be used.

[0033] Alternatively, the method for functionalizing a) the organohydrogensiloxane to form a’) 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.

[0034] Hydrosilylation reaction catalysts suitable for starting material b) in the method for functionalizing the organohydrogensiloxane as described and exemplified above for starting material A) in the method for preparing the first hydrosilylation reaction product comprising the organohydrogensiloxane. Starting material b) is optional, for example, additional hydrosilylation reaction catalyst may not be needed if starting material A) is present in the first hydrosilylation reaction product or if said catalyst is not inhibited, deactivated, or removed from the organohydrogensiloxane of formula a-1). Alternatively, starting material b) may be added when A) the hydrosilylation reaction catalyst used to make the organohydrogensiloxane is a platinum hydrosilylation reaction catalyst that is complexed with F) the thiuram disulfide in the method as described above. Alternatively, starting material b) may not be needed even if A) the platinum hydrosilylation reaction catalyst is complexed with F) the thiuram disulfide in the first hydrosilylation reaction product if the conditions (e.g., temperature) selected for the method forfunctionalizing the organohydrogensiloxane are sufficient to decomplex starting materials A) and F). Starting material b) may be the same or a different species as that selected for use above to make the first hydrosilylation reaction product comprising organohydrogensiloxane. For example, starting material b) may be a hydrosilylation reaction catalyst comprising a platinum group metal other than platinum, e.g., a rhodium catalyst. Without wishing to be bound by theory, it is thought that when the thiuram disulfide is tetra(methyl)thiruam disulfide, then starting material b) is present and comprises the metal other than platinum; however, when the starting material F) is a thiuram disulfide compound other than tetra(methyl)thiruam disulfide, then starting material b) is optional. However, the amount of the hydrosilylation reaction catalyst used in this method to functionalize the organohydrogensiloxane 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). Alternatively, when starting material b) is used, it may be added at a concentration of 1 ppm or more, alternatively 10 ppm or more, alternatively 20 ppm or more, alternatively 30 ppm or more, alternatively 40 ppm or more, alternatively 50 ppm or more, alternatively 60 ppm or more, alternatively 70 ppm or more, alternatively 80 ppm or more, alternatively 90 ppm or more, alternatively 100 ppm or more, alternatively 120 ppm or more, alternatively 140 ppm or more, alternatively 160 ppm or more, alternatively 180 ppm or more; while at the same time starting material b) may be added at a concentration of 200 ppm or less, alternatively 180 ppm or less, alternatively 160 ppm or less, alternatively 140 ppm or less, alternatively 120 ppm or less, alternatively 110 ppm or less, alternatively 100 ppm or less, alternatively 80 ppm or less, on the same basis above.

[0035] Starting material c) the reactive species introduced above for functionalizing a) the organohydrogensiloxane may comprise a silane of formula c-1): 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 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, USAor Gelest, Inc. of Morrisville, Pennsylvania, USA. Exemplary silanes include allyltrimethoxysilane, allyltriethoxysilane, or a combination thereof.

[0036] 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 the reactive 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, 4-vinyl-l -cyclohexene 1,2-epoxide, 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.

[0037] 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 instance, 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.

[0038] Starting material e) the hydrosilylation reaction inhibitor may be as described and exemplified above for starting material E) in the method for preparing the first hydrosilylation reaction product comprising a) the organohydrogensiloxane. The amount of e) inhibitor selected for use in this method for preparing the second hydrosilylation reaction product comprising a’ ) the functionalized organosiloxane depends on various factors 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.

[0039] The starting materials used in the method for functionalizing theorganohydrogensiloxane may optionally further comprise one or more additional starting materials. The additional starting materials may be those additional ingredients disclosed in US Patent 9593209 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.

[0040] The method described above produces the second hydrosilylation reaction product comprising a’) the functionalized organosiloxane. The functionalized organosiloxane comprisessubscript n,R1, D, and L are as described above, and each R2is 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 R2per molecule is the functional group (z.e., at least one instance of R2per molecule is not hydrogen). Alternatively, 1 to 4 instances of R2per 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 R2per molecule are the functional groups (other than hydrogen). Alternatively, one instance of R2on each cyclic siloxane ring may be the functional group and the other instances of R2may be H. Alternatively, two instances of R2on each cyclic siloxane ring may be the functional group and the other instances of R2may be H. Alternatively, three instances of R2on each cyclic siloxane ring may be the functional group and the other instances of R2may be H. Alternatively, a’) may be fully functionalized, wherein each instance of R2on each cyclic siloxane ring is the functional group (with no instances of R2being H). The functional group for R2is derived from starting material c) the reactive species described above. The functional group for R2may be independently selected from the group consisting of R4SiR5(4-y), and R6R7, where R5and R7are as described above, and R4and R6are divalent hydrocarbyl 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 organohydrogensiloxane. 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.

[0041] Alternatively, the functionalized organosiloxane may have formula a’ -2):subscript n, D, R3, and RA1are as described and exemplified above. Alternatively, the functionalized organosiloxane may have formula a’-3):subscript n has an average value of 4 to 6, Ph means phenyl, and each R2is H or an epoxyfunctional group, such as glycidoxypropyl, with the proviso that at least one instance of R2per molecule is the epoxy-functional group.

[0042] Alternatively, the functionalized organosiloxane may have formula a’ -4):n, D, R3, and RArare as described and exemplified above. Alternatively, the functionalized organosiloxane may have formula a’ -5):has an average value of 4 to 6, Ph means phenyl, and each R2is H or an epoxy-functional group, such as glycidoxypropyl, with the proviso that at least one instance of R2per molecule is the epoxy-functional group.

[0043] The functionalized organosiloxane of formula a’-2), a’-3), a’-4), and / or a’-5) described above may be used as an adhesion promoter in a curable silicone composition, such as a liquid silicone rubber composition. The products described above, e.g., a) the organohydrogensiloxane of formula a- 2), a-3), a-4), or a-5), and a’) the functionalized organosiloxane of formula a’ -2), a’ -3), a’ -4), and a’ -5) are useful in curable silicone compositions as adhesion promoters. Alternatively, a) the organohydrogensiloxane (of any of formula a-1) to a-5)) and / or a’) the functionalized organosiloxane (of any of formulas a’ 1) to a’ -5)) may be useful as a crosslinker or co-crosslinker in hydrosilylation reaction curable compositions, such as a silicone release coating composition.

[0044] 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 organopoly siloxane 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.

[0045] Alternatively, the curable silicone composition may be a silicone release coating composition, such as that described in US Patent Application Publication 2022-0025125, in which a) the organohydrogensiloxane described herein is used in addition to, or instead of, the polyfunctional organohydrogensiloxane of US Patent Application Publication 2022-0025125.

[0046] 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.

[0047] 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.

[0048] 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. 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. 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); polyarylates (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).

[0049] 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 8hours, 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.

[0050] Curing the curable silicone composition typically may have a dwell time of 0.1 second and 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).

[0051] 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.

[0052] 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 andmay 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.

[0053] The article, which comprises the cured silicone (formed from the curable silicone composition) adhered to the substrate, may have varying dimensions, including relative thicknesses 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 film 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] When the curable silicone composition includes a solvent, the method may furthercomprise: 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

[0058] These examples are intended to illustrate the invention and should not be interpreted as limiting 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

[0059] In this Example 1, an organohydrogensiloxane was prepared as follows:1) Set-up: 3000 ml 4-neck round bottom (RB) flask with dropping funnel, multiport with 2 inlets for dry N2 (Drierite column) and dry air (Drierite column), temperature controller (attached to hot plate with over-temperature protection) and reflux condenser with cooling circulator attached.2) Load toluene into the 3000 ml 4-neck RB flask together with 1% Pt (hexachloroplatinic acid : 6 H2O) in IPA solution. Target Pt-concentration <5 ppm.3) Dry starting material Bl) MV1DPh2MV1at the rotary evaporator at 115 °C, 0 mbar over 2-3 hours.4) Load a mixture of starting material C2) stripped MH- 1109 and starting material Bl) MV1DPh2MV1in amounts to provide 1.5 Si-Vinyl / MHl 109 ratio into the dropping funnel.5) Open one port to introduce dry air into the RB flask (reactor) and to kick-off the hydrosilylation reaction and continue over the whole hydrosilylation reaction.5) Start stirring and bring the reactor temperature up to 75 °C. Once a stable temperature is established start adding in the mixture dropwise from the dropping funnel.6) Adjust the speed of addition to let the temperature increase to 77 - 80 °C to maintain a stable exothermic reaction. Occasional application of heat or removal of the heating mantle may be necessary to keep the reaction going or to keep the exotherm in check.7) Once all mixture from the dropping funnel has been added to the reaction stir for ca 1 h at 75 °C, then take a sample and analyze to monitor the Si- Vinyl consumption with1H NMR.8) Once completion of the reaction has been confirmed (all Vi consumed, check with 'H NMR) remove the heating block and let the reaction cool to 60 °C.9) Add 1 weight % solution of n-Bu-thiuram in toluene at 60 °C (3.5:1 ratio with Pt).10) Remove the heating block and stir for 3 hours without heating and let the reactor temperature drop to 24 °C.11) Transfer the reaction mixture to a receiving flask.12) Remove the volatiles by rotary evaporator at 95 °C at 0-1 mbar for 2 hours.13) Transfer the product into a Nalgene bottle and keep under N2. Analyze by 1H, 13C and 29SiNMR.

[0060] The reaction scheme is exemplified below. One skilled in the art would recognize that the structure shown is exemplary and not limiting because MH- 1109 can contain higher DP siloxanes in addition to tetramethyl cy cl otetrasil oxane, therefore, Organohydrogensiloxane 1 may comprise a mixture of the structure shown with organohydrogensiloxanes having 5 and 6 siloxane units in each ring.rgano y rogens oxane nBu Thiuram added as Pt inhibitor in 3.5: 1 rationBu-Thiuram

[0061] In this Example 2, the organohydrogensiloxane prepared in Example 1 was functionalized as follows: A 4-neck round bottom flask was charged with Organohydrogensiloxane 1 prepared in Example 1 (94.09 g). The flask was equipped with a magnetic stir bar, a cooled condenser equipped with an outlet leading to a bubbler, a thermocouple fitted with a nitrogen inlet, and an addition funnel which was charged with allyl glycidyl ether (AGE, 121.32 g). Organohydrogensiloxane 1 was heated to 65-80 °C, followed by the addition of ca. 2.8 g AGE upon stirring. Exotherm was observed immediately. AGE was added gradually at a rate to keep the reaction temperature below 95 °C. Karstedt’s catalyst (2 ppm Pt, 1 wt% solution in toluene) was added via micropipette once the exotherm began to stall. After addition of AGE was complete the reaction mixture was stirred at 80 °C for another 30 min. The SiH consumption was monitored by a Perkin Elmer FTIR fitted with an ATR plate. After cooled to ambient temperature, the reaction mixture was charged and mixed with 1- ethyny 1-1 -cyclohexanol (0.55 g, 0.17 wt%), before transferred to a Nalgene bottle. The product was stripped over three days in a vacuum chamber under 0 mmHg at ambient temperature, to remove excess AGE. The sample was analyzed by 1H, 13C and 29Si NMR as well as GPC, which confirmed that a partially substituted structure, having an average of one glycidoxypropyl group bonded to a silicon atom was present on each cyclic siloxane moiety.

[0062] Without wishing to be bound by theory, it is thought that the thiuram disulfide used in Example 1 complexed with the platinum in the hydrosilylation reaction catalyst used in Example 1, which stabilized the organohydrogensiloxane during removal of the volatiles and storage between Example 1 and Example 2, however, at the temperatures used in Example 2, the hydrosilylation reaction proceeded even in the presence of the thiuram disulfide.

[0063] In this Example 3, the organohydrogensiloxane prepared in Example 1 was functionalized as follows: A 3-neck round bottom flask was charged with Organohydrogensiloxane 1 prepared in Example 1 (63.723 g). The flask was equipped with a magnetic stir bar, a cooled condenser equipped with an outlet leading to a bubbler, a thermocouple fitted with a nitrogen inlet, and an addition funnel which was charged with allyl glycidyl ether (AGE, 50.63 g). Organohydrogensiloxane 1 was heated to 65-80 °C, followed by the addition of ca. 4.6 g AGE upon stirring. Exotherm was observed immediately. AGE was added gradually at a rate to keep the reaction temperature below 100 °C. Karstedt’s catalyst (2 ppm Pt, 1 wt% solution in toluene) was added via micropipette once the exotherm began to stall. After addition of AGE was complete the reaction mixture was stirred at 80 °C for another 30 min. The SiH consumption was monitored by a Perkin Elmer FTIR fitted with an ATR plate. After cooled to ambient temperature, the reaction mixture was charged and mixed with 1- ethyny 1-1 -cyclohexanol (0.42 g, 0.37 wt%), before transferred to a Nalgene bottle. The productwas stripped using short path distillation under 5 mmHg at 40 °C for 3-4 hours, to remove excess AGE. The sample was analyzed by 1H, 13C and 29Si NMR as well as GPC, which confirmed that a fully substituted structure, having each silicon bonded hydrogen atom in the organohydrogensiloxane was replaced by a glycidoxypropyl group.

[0064] In this Example 4, an organohydrogensiloxane was prepared as follows:1 ) Set-up: 3000 ml 4-neck round bottom (RB) flask with dropping funnel, multiport with 2 inlets for dry Nr (Drierite column) and dry air (Drierite column), temperature controller (attached to hot plate with over-temperature protection) and reflux condenser with cooling circulator attached.2) Load toluene into the 3000 ml 4-neck RB flask together with 1% Pt (hexachloroplatinic acid 6 H O) in IP A solution. Target Pt-concentration <5 ppm.3) Dry starting material B2) MViPhMViPhat the rotary evaporator at 115 °C, 0 mbar over 2-3 hours.4) Load a mixture of starting material C2) stripped MH- 1109 and starting material B2) MViPhMViPh(1.5 Si-Vinyl / MH-1109 ratio) into the dropping funnel.5) Open one port to introduce dry air into the pot and to kick-off the hydrosilylation reaction and continue over the whole hydrosilylation reaction.5) Start stirring and bring the reactor temperature up to 75 °C. Once a stable temperature is established start adding the mixture in the dropping funnel dropwise.6) Adjust the speed of addition to let the temperature increase to 77 - 80 °C to maintain a stable low key exothermic reaction. Occasional application of heat or removal of the heating mantle may be necessary to keep the reaction going or to keep the exotherm in check.7) Once all of the mixture in the dropping funnel has been added to the reaction flask, stir for ca 1 h at 75 °C, then take a sample and analyze to monitor the Si-Vinyl consumption with 1H NMR.8) On completion of reaction being confirmed (all Vi consumed, check with 1H NMR) remove the heating block and let the reaction cool to 60 °C.9) Add 1 wt% solution of nBu-thiuram in toluene at 60 °C (3.5:1 molar ratio with Pt).10) Remove the heating block and stir for 3 hours w / o heating and let the flask temperature drop to 24 °C.11) Transfer the reaction mixture to a receiving flask.12) Remove the volatiles by rotor evaporator at 95 °C at 0-1 mbar for 2 hours.13) Transfer the product into a Nalgene bottle and keep under N2. Analyze by 1H, 13C and 29Si NMR.

[0065] The reaction scheme is exemplified below. One skilled in the art would recognize thatthe structure shown is exemplary, not limiting, because MH-1109 can contain higher DP siloxanes in addition to tetramethylcyclotetrasiloxane therefore, Organohydrogensiloxane 2 may comprise a mixture of the structure shown with organohydrogensiloxanes having 5 and 6 siloxane units in each ring.MH-1 109, Excess B2) Organohydrogensiloxane 2 add nBu Thiuram as Pt inhibitor in a 3.5:1 rationBu-Thiuram

[0066] In this Example 5, A 3 -neck round bottom flask was charged with Organohydrogensiloxane 2 prepared in Example 4 (116.38 g). The flask was equipped with a magnetic stir bar, a cooled condenser equipped with an outlet leading to a bubbler, a thermocouple fitted with a nitrogen inlet, and an addition funnel which was charged with allyl glycidyl ether (AGE, 50.63 g). Organohydrogensiloxane 2 was heated to 65-80 °C, followed bythe addition of ca. 3.4 g AGE upon stirring. Exotherm was observed immediately. AGE was added gradually at a rate to keep the reaction temperature below 110 °C. No additional catalyst was added to the reaction. After addition of AGE was complete the reaction mixture was stirred at 80 °C for another 30 min. The SiH consumption was monitored by a Perkin Elmer FTIR fitted with an ATR plate. After cooled to ambient temperature, the reaction mixture was charged and mixed with 1-ethynyl-l -cyclohexanol (0.255 g, 0. 17 wt%), before transferred to a Nalgene bottle. The sample was analyzed by 1H, 13C and 29Si NMR as well as GPC.

[0067] In this Example 6, A 3 -neck round bottom flask was charged with Organohydrogensiloxane 2 prepared in Example 4 (77.41 g). The flask was equipped with a magnetic stir bar, a cooled condenser equipped with an outlet leading to a bubbler, a thermocouple fitted with a nitrogen inlet, and an addition funnel which was charged with allyl glycidyl ether (AGE, 73.723 g). Organohydrogensiloxane 2 was heated to 65-80 °C, followed by the addition of ca. 3.4 g AGE upon stirring. Exotherm was observed after about 30 sec. AGE was added gradually at a rate to keep the reaction temperature below 80 °C. Karstedt’s catalyst (3 ppm Pt, 1 wt% solution in toluene) was added via micropipette once the exotherm began to stall. After addition of AGE was complete the reaction mixture was stirred at 80 °C for another 30 minutes. The SiH consumption was monitored by a Perkin Elmer FTIR fitted with an ATR plate. After cooled to ambient temperature, the reaction mixture was charged and mixed with 1- ethynyl-1 -cyclohexanol (0.255 g, 0.17 wt%), before transferred to a Nalgene bottle. The product was stripped overnight in a vacuum chamber, 0 mmHg and ambient temperatures, to remove excess AGE. The sample was analyzed by]H,13C and29Si NMR as well as GPC.

[0068] In this Reference Example 7, organohydrogensiloxanes were prepared by the following general procedure: First, a vinyl-terminated siloxane and a cyclic polyorganohydrogensiloxane in amounts shown below in Table 3 were mixed in a reactor. If toluene was used, it was added to the reactor and mixed. The reactor contents were heated to a temperature of 60 °C to 80 °C, and then a platinum hydrosilylation reaction catalyst was added. Mixing continued for 30 minutes to 1 hour for hydrosilylation reaction to occur. After this, DAM or a Stabilizer described in Table 1 was added at a 3: 1 molar ratio with respect to Pt metal in the hydrosilylation reaction catalyst. Mixing continued while cooling the reactor content to RT over at least 3 hours. After this, stripping via rotary evaporator at 2-4 torr to remove unreacted cyclic polyorganohydrogensiloxane and solvent was performed with heating at 100 °C to 140 °C. A first hydrosilylation reaction product was prepared.Table 3 - Starting Materials used in Reference Example 7, amounts in weight parts

[0069] Comparative example 7-1 (C7-1), which contained no stabilizer or inhibitor (no diallyl maleate and no thiuram disulfide) exhibited gelation within 1 hour during stripping.Comparative example 7-2 (C7-2), which contained diallyl maleate exhibited gelation after storage for > 6 months. Comparative example 7-3 (C7-3) exhibited gelation after storage at 23- 25 °C for more than 3 weeks, indicating dodecyl disulfide is not a sufficient stabilizer for long term gel stability. Working example 7-1 (W7-1) did not exhibit gelation after storage for > 6 months. Each of Working examples 7-2 to 7-5 (W7-2 to W7-5) similarly did not exhibit gelation after storage for > 6 months. The results indicate that the thiuram disulfide described herein is a sufficient stabilizer for long term stability against gelation.

[0070] In this Reference Example 8, epoxy-functionalized organosiloxanes were prepared by the following general procedure: An organohydrogensiloxane prepared according to Reference Example 7 and toluene (if used) were then added to a reactor and heated to 80 °C. A rhodium based hydrosilylation reaction catalyst and a vinyl-functional epoxide were added. The reactor contents were heated at 100 °C to 120 °C for 2 to 3 hours for hydrosilylation reaction to occur. After this, stripping to remove unreacted vinyl-functional epoxide and residual toluene was performed.

[0071] In the procedure above, if the vinyl-functional epoxide was VCMX, a few drops of VCMX were added before adding [RhCl(PPti3)3] (80 - 100 ppm) to catalyze the hydrosilylation reaction. VCMX was then added dropwise over 20-30 minutes before increasing the reactor temperature to 100 - 120 °C. The mixture was stirred for at least 2 hours while under a nitrogen sweep. The heating was then discontinued, and the reactor temperature dropped to 24 °C after at least 3 hours while stirring. The reaction mixture was then transferred to a receiver and volatiles were then removed by rotary evaporation at 120 - 130 °C at 2-4 torr for 4 hours. The final sample was a brown liquid, and the composition was analyzed by1H,29Si NMR and GPC. Results of the analysis are shown below in Table 5.

[0072] In the procedure above, when the vinyl-functional epoxide was AGE, a few drops of AGE were added before adding CPA in IP A (10 ppm) to catalyze the hydrosilylation. AGE was then added dropwise over 20-30 minutes before increasing the reactor temperature to 100 - 120 °C. The mixture was stirred for at least 3 hours while under a nitrogen sweep. The heating was then discontinued, and the reactor temperature dropped to 24 °C after at least 3 hours while stirring. The reaction mixture was then transferred to a receiver and volatiles were then removed by rotary evaporation at 100 - 120 °C at 2-4 torr for 4 hours. The final sample was a brown liquid, and the composition was analyzed by]H,29Si NMR and gel permeation chromatography. Results of the analysis are shown below in Table 5.Table 4 - Starting Materials used in Reference Example 8, amounts are in weight partsTable 5 - Analysis Results of Samples Prepared According to Reference Example 8

[0073] The data in Tables 4 and 5 show vinyl-functional epoxide hydrosilylation with Sample 8-3 and 8-4 showed significant epoxide ring opening polymerization by a high Mw, Mz and Dispersity by size exclusion chromatography. In contrast, working examples 7-1 and 8-2 showed that the thiuram disulfide successfully prevented gelation to give a stable organohydrogensiloxane. Subsequent vinyl -functional epoxide hydrosilylation with working examples 8-2 and 8-3 demonstrated the preparation of epoxy-functionalized organosiloxanes with minimal epoxide ring opening polymerization and well-defined molecular weights.

[0074] In this Reference Example 9, additional epoxy-functionalized organosiloxanes wereprepared by using samples C7-3, W7-2, W7-3, W7-4, and W7-5 described above in Table 3, where the samples were used within 24 hours of their preparation. Amounts (g) of each starting material used are shown below in Table 6. Table 6 also contains molecular weight characteristics for the resulting epoxy-functionalized organosiloxanes as measured by GPC.

[0075] The general proecure used was as followed: Combine in a 4-neck round bottom flask the organohydrogensiloxane described in Table 3 and the Solvent 1 and mix while heating to 80 °C. Add a few drops of VCMX and then add bl) Tris(triphenylphosphine)rhodium(I) chloride diluted in THF. Dropwise add the remaining VCMX over 20 to 30 minutes and then heat to 100-120 °C while stirring. Continue stirring for 2 hours under a nitrogen gas sweep. Allow the temperature to drop to 24 °C over at least 3 hours while stirring. Transfer the reaction mixture to a receiving flask and remove volatiles by rotary evaporating at 120-130 °C at 0.27-0.53 kiloPascals (2-4 Torr) pressure for 4 hours. Analyze the resulting brown liquid by!H NMR and29Si NMR to confirm product structure. The resulting brown liquid was a combination of epoxyfunctionalized organosiloxane and platinum - thiuram disulfide complex. The epoxyfunctionalized organosiloxane had the following average structure, where n=20:

[0076] This product was also evaluated by GPC to determine molecular weight characteristics including number average molecular weight (Mn), weight average molecular weight (Mw), and z-average molecular eight (Mz), as well as molecular weight dispersity.

[0077] Comparative examples B and C (CE B and CE C) showed undesirable molecular weight build relative to Working Examples 9-1 to 9-8 (Ex 9-1 to 9-8 in Table 6, below), which is evident in the significantly higher Mw, Mz and Dispersity values. CE B used dodecyl disulfide instead of a thiuram disulfide. CE C used tetra(n-butyl)thiuram disulfide, but also used a Pt catalyst in the second hydrosilylation reaction proces. Without wishing to be bound by theory, it is thought that some reactive species, such as VCMX, may be more susceptible to side reaction, such as ring opening of the epoxy group than others, therefore, to minimize side reactions, one skilled in the art would select F) the thiuram disulfide used in the first hydrosilylation reaction,b) the hydrosilylation reaction catalyst in the second hydrosilylation reaction, and the amounts of each so as to minimize or eliminate such side reaction.

[0078] CE D failed to successfully proceed in the second hydrosilylation reaction. CE D used tetra(methyl)thiuram disulfide but no additional b) hydrosilylation reacction catalyst in the second hydrosilylation reaction (that is, no additional catalyst for the second hydrosilylation reaction process of the present invention). In contrast, Ex 9-8 also used tetra(methyl)thiuram disulfide in combination with additional rhodium hydrosilylation reaction catalyst in the second hydrosilylation reaction and resulted in desirable product. Without wishing to be bound by theory it is thought that when a cyclic epoxy functional compound that is susceptible to ring opening, such as VCMX, is used in the second hydrosilylation reaction, and starting material F) is tetra(methyl)thiuram disulfide, then starting material b) may be used in the second hydrosilylation reaction, and starting material b) may be a non-platinum hydrosilylation reaction catalyst, as described hereinabove.

[0079] Ex 9-2, Ex 9-3, Ex 9-5 and Ex 9-7 each illustrate that starting material b) a (second) hydrosilylation reaction catalyst in the second hydrosilylation reaction was optional when using a thiuram disulfide other than tetra(methyl)thiuram disulfide.Table 6 - Starting Materials and Results with Additional Thiuram Disulfides

[0080] In the examples above, GPC evaluation was performed in toluene using a Waters 2695 LC pump and autosampler equipped with two Agilent PLgel Mixed C columns calibrated with polystyrene standards.

[0081] Abbreviations used in the specification have the definitions in Table A, below.Table A - Abbreviations

[0082] 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 alsoanything subsumed therein, as well as endpoints. 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.

Claims

CLAIMS:

1. An organohydrogensiloxane comprising formula:each subscript n is independently selected and has a value of 2 to 18; each R1is an independently selected monovalent hydrocarbyl group; each D is independently a divalent hydrocarbyl group of 2 to 6 carbon atoms;L is a divalent linking moiety selected from the group consisting;wherein each RAris an independently selected monovalent aromatic group and each R3is an independently selected alkyl group.

2. The organohydrogensiloxane of claim 1, wherein each subscript n independently has an average value of 2 to 4, each R1is methyl or ethyl; each R3is methyl or ethyl; and each RAris selected from the group consisting of phenyl, tolyl, and xylyl.

3. The organohydrogensiloxane of claim 1 or claim 2, wherein each subscript n has an average value of 2 to 3, each R1is methyl,R3is methyl, andRAIis phenyl.

4. A composition comprising: the organohydrogensiloxane of any one of claims 1 to 3 and a thiuram disulfide.

5. A method for preparing the organohydrogensiloxane of any one of claims 1 to 3, or the composition of claim 4, wherein the method comprises:1) combining, under conditions to effect hydrosilylation reaction, starting materialscomprising:A) a hydrosilylation reaction catalyst;B) an alkenyl-functional siloxane selected from the group consisting of, wherein R3and RA|are as described above, and each RV1is an independently selected alkenyl group;C) a cyclic polyorganohydrogensiloxane of unit formula (R]HSiO2 / 2)v, where subscript v has an average value of 4 to 20 (v = n-2), and each R1is as described above; optionally E) a hydrosilylation reaction inhibitor; optionally D) a solvent; and optionally all or a portion of F) a thiuram disulfide; thereby preparing a hydrosilylation reaction product comprising a) the organohydrogensiloxane, the hydrosilylation reaction catalyst, and, when present, the hydrosilylation reaction inhibitor and the solvent; and optionally 2) combining the hydrosilylation reaction product or a) the organohydrogensiloxane and all or a portion of F) the thiuram disulfide; and optionally 3) purifying the organohydrogensiloxane.

6. An organosiloxane comprising formula:, wherein each subscript n is independently has a value of 2 to 18; each R1is an independently selected monovalent hydrocarbyl group; each R2is 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 alkoxy group, an epoxy group, an isocyanate group, a methacrylate group, and a urethane group; with the proviso that at least one instance of R2per molecule is the functional group; each D is independently a divalent hydrocarbyl group of 2 to 6 carbon atoms;L is a divalent linking moiety selected from the group consisting, wherein each R|is an independently selected monovalent aromatic group and each R3is an independently selected alkyl group.

7. The organosiloxane of claim 6, wherein each subscript n independently has an average value of 2 to 4, each R1is methyl or ethyl; each R3is methyl or ethyl; each RAris selected from the group consisting of phenyl, tolyl, and xylyl; and an average of two to four instances of R2per molecule are the functional group.

8. The organosiloxane of claim 6 or claim 7, wherein each subscript n has an average value of 2 to 3, each R1is methyl,R3is methyl,R|is phenyl, and each R2is selected from H, and an epoxy-functional group.

9. The organosiloxane of any one of claims 6 to 8, wherein the functional group is a glycidoxypropyl functional group.

10. A composition comprising: the organosiloxane of any one of claims 6 to 9 and a thiuram disulfide.

11. A method for preparing the organosiloxane of any one of claims 6 to 9, wherein the method comprises:1) combining, under conditions to effect a first hydrosilylation reaction, starting materials comprising:A) a hydrosilylation reaction catalyst;B) an alkenyl-functional siloxane selected from the group consisting of, wherein R3and RArare as described above, and each RV1is an independently selected alkenyl group;C) a cyclic polyorganohydrogensiloxane of unit formula (R’HSiChc , wherein subscript vhas an average value of 4 to 20 (v = n-2), and each R1is as described above; optionally E) a hydrosilylation reaction inhibitor; optionally D) a solvent; and optionally all or a portion of F) a thiuram disulfide; thereby preparing a first hydrosilylation reaction product comprising a) an organohydrogensiloxane and the hydrosilylation reaction catalyst, and, when present the hydrosilylation reaction inhibitor and / or the solvent; and optionally 2) combining the hydrosilylation reaction product or a) the organohydrogensiloxane and all or a portion of F) the thiuram disulfide; and optionally 3) purifying the organohydrogensiloxane.4) combining, under conditions to effect a second hydrosilylation reaction, starting materials comprising the first hydrosilylation reaction product or a) the organohydrogensiloxane, optionally b) a second 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 a) the organohydrogensiloxane and further comprising a moiety comprising a functional group; thereby preparing a second hydrosilylation reaction product comprising the organosiloxane; optionally 5) adding a thiuram disulfide to the second hydrosilylation reaction product; and optionally 6) recovering the organosiloxane.

12. The method of claim 11, wherein c) the reactive species comprises a silane of formula R4ySiR5(4-y), wherein 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, an anhydride group, or a urethane group.

13. The method of claim 11, where c) the reactive species comprises an organic compound of formula R6R7, wherein each R6is the aliphatically unsaturated group capable of undergoing an addition reaction, and R7is 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, an anhydride group, and a urethane group.

14. The method of claim 13, wherein R6is an alkenyl group and R7is an epoxy-functional group.

15. A method for preparing a functionalized organosiloxane, wherein the method comprises:1) combining, under conditions to effect a first hydrosilylation reaction, starting materials comprising:A) a platinum hydrosilylation reaction catalyst;B) an alkenyl-functional siloxane of formulasubscript x is an integer with a value of 0 to 1 ,000; each RV1is an independently selected alkenyl group, and each RMis an independently selected monovalent hydrocarbyl group with 1 to 20 carbon atoms;C) a cyclic polyorganohydrogensiloxane of unit formula (R’HSiChclv, where subscript v has an average value of 4 to 20, and each R1is an independently selected monovalent hydrocarbyl group; optionally D) a solvent; thereby preparing a first hydrosilylation reaction product comprising a) an organohydrogensiloxane and the hydrosilylation reaction catalyst, and, when present the hydrosilylation reaction inhibitor and / or the solvent; and optionally 2) combining the hydrosilylation reaction product or a) the organohydrogensiloxane and F) a thiuram compound; and optionally 3) purifying the organohydrogensiloxane.4) combining, under conditions to effect a second hydrosilylation reaction, starting materials comprising the first hydrosilylation reaction product or a) the organohydrogensiloxane, optionally b) a second 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 a) the organohydrogensiloxane and further comprising a moiety comprising a functional group; thereby preparing a second hydrosilylation reaction product comprising the organosiloxane; optionally 5) adding a thiuram disulfide to the second hydrosilylation reaction product; and optionally 6) recovering the functionalized organosiloxane.

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