Polyorganohydrogensiloxane composition containing a Lewis acidic monocationic phosphonium salt

Abstract

A composition containing a phosphonium catalyst and a polyorganohydrogensiloxane. The composition is storage stable at room temperature and cures when heated. This composition and method are useful for preparing polyorganosiloxane products such as coatings, adhesives, elastomers, and foams.

Description

Technical Field

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 352,315, filed on June 15, 2022, under 35 U.S.C. § 119(e). U.S. Provisional Patent Application No. 63 / 352,315 is incorporated herein by reference.

[0002] There are provided curable polyorganosiloxane compositions, and methods for their preparation and curing. More particularly, the curable polyorganosiloxane compositions include a monocationic Lewis acidic phosphonium salt (catalyst) and a polyorganohydrogensiloxane.

[0003] Introduction It has been found that in the presence of a strong Lewis acid, silicon from a siloxane bond binds to the hydrogen of a silyl hydride, while the silicon of the silyl hydride binds to the oxygen of the siloxane bond, causing a rearrangement reaction. Surprisingly, the silyl hydride and the siloxane bond involved in the rearrangement reaction can be on the same molecule or on different molecules. This rearrangement reaction tends to be rapid in the presence of a strong Lewis acid. Such reactions can be useful for rapid curing systems containing Si-H and siloxane bonds without the need for water or moisture. However, a two-component system is required for storage to keep the Lewis acid catalyst away from the combination of silyl hydride and siloxane bond until such curing is desired. It is desirable to provide a one-component system with storage stability that utilizes a rearrangement reaction and is stable at room temperature but can be triggered to cure by heating.

Summary of the Invention

[0004] A curable polyorganohydrogensiloxane composition (the composition) includes (A) a phosphonium catalyst and (B) a polyorganohydrogensiloxane. Methods for preparing and curing the composition are provided.

Detailed Description of the Invention

[0005] The composition introduced above contains (A) a phosphonium catalyst and (B) a polyorganohydrogensiloxane. The phosphonium catalyst contains (i) a tetravalent monocation of phosphorus and (ii) a non-coordinating anion.

[0006] Starting material (A) phosphonium catalyst The starting material (A) used herein is a phosphonium catalyst containing (i) a tetravalent monocation of phosphorus and (ii) a non-coordinating anion. The tetravalent monocation of phosphorus is a Lewis acidic phosphorus cation of formula (i-1): [PR 1 3R 2 + , wherein each R 1 is an independently selected aryl halide group, and each R 2 is independently selected from the group consisting of a halogen atom and an electron-withdrawing group.

[0007] The aryl halide group R 1 may have the following formula:

Chemical formula

[0008] The halogen atom of R 2 may be selected from the group consisting of bromine (Br), Cl, and F, or may be Cl or F. The halogen atom of R 2 may be F. The halogen atom of R 2 ​The electron-withdrawing group may contain an atom with an electronegativity of ≧2.5 such as carbon (C) or oxygen (O) bonded to P. Alternatively, the electron-withdrawing group may have the formula -CX’3, where X’ is a halogen atom selected from Br, Cl, or F, or is Cl or F. Alternatively, R 2 The electron-withdrawing group may have the formula -CF3. Alternatively, R 2 The electron-withdrawing group may have the formula -OR 9 wherein R 9 is alkyl or aryl. The alkyl group suitable for R 9 may be linear, branched, cyclic, or a combination of two or more thereof. The alkyl group is exemplified by methyl, ethyl, propyl (including n-propyl and / or isopropyl), butyl (including n-butyl, tert-butyl, sec-butyl, and / or isobutyl), pentyl, hexyl, heptyl, octyl, decyl, dodecyl, undecyl, and octadecyl (and branched-chain isomers having 5 to 18 carbon atoms), and the alkyl group is further exemplified by cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. The aryl group suitable for R 9 may be monocyclic or polycyclic and may have pendant hydrocarbyl groups. For example, the aryl group for R 9 includes phenyl, tolyl, xylyl, and naphthyl, and further includes aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl. Alternatively, the aryl group for R 9 may be monocyclic such as phenyl, tolyl, or benzyl, or the aryl group for R 9 may be phenyl.

[0009] Alternatively, in formula (i-1), each R 1 may be a fluorinated aryl group. Alternatively, in formula (i-1), R 2 may be F. Alternatively, (i) the tetravalent monocation of phosphorus may have the formula: [P(C6F5)3F] +

[0010] ​(A) In the phosphonium catalyst, (ii) the anion is a non-coordinating anion. The non-coordinating anion can have a charge that is not localized on a specific atom but is delocalized over the surface of the anion. Suitable non-coordinating anions include trifluoromethanesulfonate (triflate) of the formula [CF3SO3] - and anions of the formula [BR 3 4] - wherein each R 3 is independently selected from the group consisting of monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups. The monovalent hydrocarbon group can be an alkyl group or an aryl group. The monovalent halogenated hydrocarbon group can be an alkyl group or an aryl group in which one or more hydrogen atoms are replaced by F, Cl, or Br.

[0011] R 3 Suitable alkyl groups for 3Alkyl groups suitable for [description] are exemplified by methyl, ethyl, propyl (including n-propyl and / or isopropyl), butyl (including n-butyl, tert-butyl, sec-butyl, and / or isobutyl), pentyl, hexyl, heptyl, octyl, decyl, dodecyl, undecyl, and octadecyl (and branched-chain isomers having 5 to 18 carbon atoms), and the alkyl group is further exemplified by cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. Suitable halogenated alkyl groups include chlorinated alkyl groups such as chloromethyl group and chloropropyl group, fluorinated alkyl groups such as fluoromethyl, difluoromethyl, trifluoromethyl, 2-fluoropropyl, 3,3,3-trifluoropropyl, 4,4,4-trifluorobutyl, 4,4,4,3,3-pentafluorobutyl, 5,5,5,4,4,3,3-heptafluoropentyl, 6,6,6,5,5,4,4,3,3-nonafluorohexyl, and 8,8,8,7,7-pentafluorooctyl, chlorinated cycloalkyl groups such as 2,2-dichlorocyclopropyl and 2,3-dichlorocyclopentyl, and fluorinated cycloalkyl groups such as 2,2-difluorocyclopropyl, 2,3-difluorocyclobutyl, 3,4-difluorocyclohexyl, and 3,4-difluoro-5-methylcycloheptyl, but are not limited thereto.

[0012] R 3 The aryl group suitable for [description] can be monocyclic or polycyclic and can have pendant hydrocarbyl groups. For example, the aryl group of R 3 includes phenyl, tolyl, xylyl, and naphthyl, and further includes aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl. Alternatively, the aryl group of R 3 can be monocyclic such as phenyl, tolyl, or benzyl, or the aryl group of R 3 can be phenyl. The halogenated aryl group of R 3 can be as described above for R 1 .

[0013] Alternatively, the non-coordinating anion may be completely saturated and may not have free valence electrons that participate in covalent or coordination bonds with phosphonium. The completely saturated anion may have the formula [BR 3 4] - wherein each R 3 is independently selected from the group consisting of monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups as described above. Alternatively, each R 3 may be a halogenated aryl group. Alternatively, the anion may have the formula B(C6F5)4.

[0014] Alternatively, the catalyst (A) may have the following formula:

Chemical formula

[0015] The starting material (A) can be prepared by methods known in the art, such as those disclosed in Science 2013, 341, 1374 - 1377, by varying the appropriate starting materials. The starting material (A) used herein may be any one of the above catalysts or a combination of two or more of the above catalysts.

[0016] The composition described herein contains (A) a catalyst in an amount sufficient to cure the composition. The exact amount of the (A) catalyst depends on various factors, including the selection of (B) the polyorganohydrogensiloxane and whether (C) a (non-functional) polyorganosiloxane is present. However, the composition may contain a catalyst sufficient to provide a concentration of the tetravalent monocation of phosphorus that can be at least 1 ppm, or at least 2 ppm, or at least 5 ppm. On the other hand, at the same time, this amount can be at most 1,000 ppm, or at most 500 ppm, or at most 100 ppm, or at most 50 ppm, each based on the total weight of the starting materials (A) and (B) (and (C) if present). Alternatively, the amount of the (A) phosphonium catalyst can be from 1 ppm to 1,000 ppm, or from 2 ppm to 500 ppm, or from 5 ppm to 100 ppm, or 10 ppm, based on the weight of (B) the polyorganohydrogensiloxane and (C) the (non-functional) polyorganosiloxane if present in the composition.

[0017] Starting material (B) polyorganohydrogensiloxane The composition described herein further contains (B) a polyorganohydrogensiloxane. The polyorganohydrogensiloxane contains both Si-H moieties and Si-O-Si moieties. Thus, a composition containing (A) a phosphonium catalyst and (B) a polyorganohydrogensiloxane can cure to form a gel without additional components when heated. Without being bound by theory, it is believed that the (A) phosphonium catalyst catalyzes the rearrangement reaction of both the Si-H moieties and the Si-O-Si moieties in the (B) polyorganohydrogensiloxane to cure the composition.

[0018] The polyorganohydrogensiloxane has at least one Si-H moiety per molecule. Alternatively, the polyorganohydrogensiloxane can have two or more Si-H moieties per molecule, for example, two Si-H moieties per molecule, or three Si-H moieties per molecule, or more.

[0019] The polyorganohydrogensiloxane is HR 4 2SiO 1 / 2 , R 4 3SiO 1 / 2 , HR 4 SiO 2 / 2 , R 4 2SiO 2 / 2 , R 4 SiO 3 / 2 , HSiO 3 / 2 , and SiO 4 / 2 and may contain two or more siloxane units selected from the group consisting of units, wherein each R 4 is an independently selected monovalent hydrocarbon group that does not contain aliphatic unsaturation, provided that at least one unit per molecule contains an Si-H moiety (i.e., HR 4 2SiO 1 / 2 , HR 4 SiO 2 / 2 , and HSiO 3 / 2 is present in the polyorganohydrogensiloxane). The monovalent hydrocarbon group that does not contain aliphatic unsaturation can be an alkyl group or an aryl group, as described above for R 3 . Alternatively, each R 4 can be an independently selected alkyl group. Alternatively, each R 4 can be independently selected from the group consisting of methyl and phenyl. Alternatively, each R 4 can be methyl.

[0020] Alternatively, (B) the polyorganohydrogensiloxane can be linear or cyclic. For example, (B) the polyorganohydrogensiloxane can be a linear polydiorganohydrogensiloxane with the unit formula (B-1): (HR42SiO 1 / 2 ) g (R 4 3SiO 1 / 2 ) h (R 4 2SiO 2 / 2 ) i (HR 4 SiO 2 / 2 ) jcomprising, wherein R 4 is as defined above, and the subscripts g, h, i, and j have values such that g≧0, h≧0, the sum (g + h)=2, i≧0, j≧0, and the sum (g + j)≧1, and the sum (i + j) is from 0 to 2,000. The sum (i + j) can be 2,000 or less, or 1,000 or less, or 750 or less, or 500 or less, or 250 or less, or 100 or less, or 50 or less. On the other hand, simultaneously, the sum (i + j) can be 0 or more, or 1 or more, or 2 or more, or 3 or more, or 4 or more, or 5 or more, or 10 or more, or 15 or more, or 20 or more. Alternatively, the sum (i + j) can be from 0 to 1,000, or from 1 to 500, or from 2 to 250, or from 3 to 100. Alternatively, the sum (i + j) can be from 1 to 100. Alternatively, the sum (i + j) can be from 2 to 50. Alternatively, the sum (i + j) can be from 5 to 25. Alternatively, when g = 0 and h = 2, j≧1 (or ≧2). Alternatively, g can be 1 and h can be 1. Alternatively, h can be 2 and h can be 0. Alternatively, i can be from 0 to 5, or from 1 to 4, or from 2 to 4, or from 3 to 3.5. Alternatively, i can be from 5 to 25. Alternatively, j can be from 1 to 10, or from 2 to 9, or from 3 to 8, or from 4 to 7, or from 5 to 6. Alternatively, when g>0, j can be 0.

[0021] Polydiorganohydrogensiloxanes suitable for use herein are exemplified by the following: (i) α,ω-dimethylhydrogensiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane), (ii) α,ω-dimethylhydrogensiloxy-terminated polymethylhydrogensiloxane, (iii) α,ω-trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane), (iv) α,ω-trimethylsiloxy-terminated polymethylhydrogensiloxane, and (v) α-dimethylhydrogen siloxy, ω-trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogen siloxane), (vi) α-dimethylhydrogen siloxy, ω-trimethylsiloxy-terminated polymethylhydrogen siloxane, (vii) Combinations of two or more of these.

[0022] Alternatively, the polyorganohydrogen siloxane can be cyclic. Cyclic polydiorganohydrogen siloxanes can contain the unit formula (B-2): (R 4 2SiO 2 / 2 ) u (R 4 HSiO 2 / 2 ) v wherein R 4 is as defined above, the subscript u is 0 or more, the subscript v is 1 or more, and the quantity (u + v) is from 3 to 15. Alternatively, u can be 0. Alternatively, u can be 0 or more, or 1 or more, or 2 or more, or 3 or more. At the same time, u can be at most 6, or at most 5, or at most 4. Alternatively, u can be from 0 to 6, or from 0 to 4, or from 0 to 2, or from 1 to 6. Alternatively, v can be 1 or more, or 2 or more, or 3 or more, or 4 or more. At the same time, v can be at most 12, or at most 10, or at most 8, or at most 6, or at most 5. Alternatively, v can have an average value of 4. Alternatively, v can be from 1 to 12, or from 2 to 10, or from 3 to 8, or from 3 to 6, or from 3 to 5. In the unit formula (B-2), each R 4 can be methyl. Examples of cyclic polyorganohydrogen siloxanes include (i) trimethylcyclotrisiloxane, (ii) tetramethylcyclotetrasiloxane, (iii) pentamethylcyclopentasiloxane, (iv) hexamethylcyclohexasiloxane, and (v) combinations of two or more of these.

[0023] Suitable polyorganohydrogensiloxanes are known in the art and are commercially available. For example, DOWSIL® 6-3570 Polymer, DOWSIL® SH 1107 Fluids, and XIAMETER® MHX-1107 Fluids are available from The Dow Chemical Company (Midland, Michigan, USA). Polydiorganohydrogensiloxanes, such as HMS-992 (trimethylsilyl-terminated polymethylhydrogensiloxane), HMS-HM271 (hydride-terminated methylhydrogensiloxane-dimethylsiloxane copolymer), and HMS-031 (trimethylsiloxy-terminated methylhydrogensiloxanedimethylsiloxane copolymer) are available from Gelest, Inc. (Morrisville, Pennsylvania, USA). Other polydiorganohydrogensiloxanes available from Gelest include HMS-H271, HMS-071, HMS-993, HMS-301 and HMS-301 R, HMS-991, HMS-993, HMS-082, HMS-151, HMS-013, HMS-053, HAM-301 (octyl-functional), and HPM-502 (phenyl-functional). Methods for preparing linear and branched polyorganohydrogensiloxanes suitable for use herein, such as hydrolysis and condensation of organohalosilanes, are well known to those skilled in the art as exemplified in U.S. Patent No. 3,957,713 (Jeram et al.), U.S. Patent No. 4,329,273 (Hardman, et al), U.S. Patent No. 4,370,358 (Hayes, et al.), U.S. Patent No. 4,707,531 (Shirahata), U.S. Patent No. 5,310,843 (Morita), and U.S. Patent No. 2,823,218 (Speier, et al.), which disclose organohydrogensiloxane oligomers, linear polymers, and cyclic polymethylhydrogensiloxanes.

[0024] The amount of (B) polyorganohydrogensiloxane in the composition depends on various factors, including the Si-H content of the polyorganosiloxane (which can be determined using quantitative infrared analysis according to ASTM E168), and any optional additional starting materials are present. However, the amount of polyorganohydrogensiloxane can be 1 wt% or more, or 5 wt% or more, or 10 wt% or more, or 20 wt% or more, or 30 wt% or more, or 40 wt% or more, or 50 wt% or more, or 60 wt% or more, or 70 wt% or more, or 80 wt% or more, or 90 wt% or more, or 95 wt% or more, or 99 wt% or more, while at the same time, the amount of polyorganohydrogensiloxane can be <100 wt%, or 99.9 wt% or less, or 99.5 wt% or less, or 99.1 wt% or less, or 95 wt% or less, or 90 wt% or less, or 85 wt% or less, or 80 wt% or less, each based on the total weight of starting materials (A), (B), and (C) in the composition. Alternatively, the amount of polyorganohydrogensiloxane can be 1 wt% to <100 wt%, or 5 wt% to <100 wt%, or 10 wt% to 99.9 wt%, or 2 wt% to 3 wt% based on the same criteria.

[0025] Alternatively, in addition to (B) polyorganohydrogensiloxane, the composition can further contain (C) polyorganosiloxane that does not contain Si-H moieties and can function as a source of Si-O-Si moieties in the curing reaction of the composition.

[0026] Starting material (C) polyorganosiloxane Starting material (C) is an optional polyorganosiloxane that does not contain Si-H moieties. The polyorganosiloxane is R 4 3SiO 1 / 2 、R 4 2SiO 2 / 2 、R 4 SiO 3 / 2 、and SiO 4 / 2It contains two or more siloxane units selected from units. In the formula, each R 4 is a monovalent hydrocarbon group independently selected and free of aliphatic unsaturation. The monovalent hydrocarbon group free of aliphatic unsaturation can be an alkyl group or an aryl group.

[0027] R 4 Suitable alkyl groups for R can be linear, branched, cyclic, or a combination of two or more thereof. Alkyl groups are exemplified by methyl, ethyl, propyl (including n-propyl and / or isopropyl), butyl (including n-butyl, tert-butyl, sec-butyl, and / or isobutyl), pentyl, hexyl, heptyl, octyl, decyl, dodecyl, undecyl, and octadecyl (and branched-chain isomers having 5 to 18 carbon atoms), and alkyl groups are further exemplified by cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. Suitable halogenated alkyl groups include chlorinated alkyl groups such as chloromethyl group and chloropropyl group, fluoromethyl, difluoromethyl, trifluoromethyl, 2-fluoropropyl, 3,3,3-trifluoropropyl, 4,4,4-trifluorobutyl, 4,4,4,3,3-pentafluorobutyl, 5,5,5,4,4,3,3-heptafluoropentyl, 6,6,6,5,5,4,4,3,3-nonafluorohexyl, and 8,8,8,7,7-pentafluorooctyl and other fluorinated alkyl groups, chlorinated cycloalkyl groups such as 2,2-dichlorocyclopropyl and 2,3-dichlorocyclopentyl, and fluorinated cycloalkyl groups such as 2,2-difluorocyclopropyl, 2,3-difluorocyclobutyl, 3,4-difluorocyclohexyl, and 3,4-difluoro-5-methylcycloheptyl, but are not limited thereto.

[0028] R 4 Suitable aryl groups for R can be monocyclic or polycyclic and can have pendant hydrocarbyl groups. For example, R 3Examples of the aryl group include phenyl, tolyl, xylyl, and naphthyl, and further include aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl. Alternatively, R 4 's aryl group can be monocyclic such as phenyl, tolyl, or benzyl. Alternatively, R 4 's aryl group can be phenyl. R 4 's halogenated aryl group has the formula: [Chemical formula] and may have the formula, where each R 8 is independently selected from H, X, and a group of the formula -CX3, each X is a halogen independently selected, provided that at least one R 8 is not H, and each X can be independently selected from Cl or F. Alternatively, each R 8 can be independently selected from the group consisting of H, Cl, F, and a group of the formula -CF3, provided that at least one R 8 is Cl, F, or -CF3. Alternatively, each R 4 can be an alkyl group independently selected. Alternatively, each R 4 can be independently selected from the group consisting of methyl and phenyl. Alternatively, each R 4 can be methyl.

[0029] The starting material (C) polyorganosiloxane may be a polydiorganosiloxane, which can be linear or cyclic. For example, the starting material (C) is a linear polydiorganosiloxane containing the unit formula (C-1): (R 4 3SiO 1 / 2 )2(R 4 2SiO 2 / 2 ), where R x 4 ​is as described above, and 1,000 ≥ x ≥ 1. Alternatively, the subscript x can be at least 1, or at least 2, or at least 3, or at least 5, or at least 10, or at least 25. On the other hand, simultaneously, the subscript x can be at most 1,000, or at most 500, or at most 250, or at most 100, or at most 50. Alternatively, the subscript X can have a value such that 500 ≥ x ≥ 1, or 250 ≥ x ≥ 2, or 100 ≥ x ≥ 5, or 50 ≥ x ≥ 10, and / or 50 ≥ x ≥ 25.

[0030] Polydiorganosiloxanes suitable for use in this specification are exemplified by the following: (i) α,ω-trimethylsiloxy-terminated polydimethylsiloxane, (ii) α,ω-dimethylphenylsiloxy-terminated poly(dimethylsiloxane / methylphenylsiloxane), (iii) α,ω-dimethylphenylsiloxy-terminated polymethylphenylsiloxane, (iv) α,ω-trimethylsiloxy-terminated poly(dimethylsiloxane / methylphenylsiloxane), (v) α,ω-trimethylsiloxy-terminated polymethylphenylsiloxane, (vi) combinations of two or more of these.

[0031] Polydiorganosiloxanes are known in the art and are commercially available. For example, DOWSIL® 200 Fluids, DOWSIL® OS Fluids, and XIAMETER® PMX-200 Silicone Fluids are commercially available from The Dow Chemical Company (Midland, Michigan, USA).

[0032] Alternatively, (C) the polydiorganosiloxane has the unit formula (C-2): (R 4 2SiO 2 / 2 ) ycan be a cyclic polydiorganosiloxane, where R 4 is as defined above, and 15 ≥ y ≥ 3. Alternatively, the subscript y can be at least 3, or at least 4, or at least 5, or at least 6, while at the same time, the subscript y can be at most 15, or at most 12, or at most 10, or at most 8, or at most 6. Alternatively, the subscript y can have a value such that 12 ≥ y ≥ 3, or 10 ≥ y ≥ 3, or 8 ≥ y ≥ 3, or 6 ≥ y ≥ 3, or 6 ≥ y ≥ 4.

[0033] Examples of cyclic polydiorganosiloxanes include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and combinations of two or more thereof. Suitable cyclic polydiorganosiloxanes are commercially available, for example, from Sigma-Aldrich, Inc. (St. Louis, Missouri, USA).

[0034] The starting material (C) is optional. However, when present, the amount of the starting material (C) depends on various factors including the type of the polyorganohydrogensiloxane selected for the starting material (B) and its Si-H content. The amount of the (C) polyorganosiloxane can be 0 to <99% by weight based on the total weight of the starting materials (A), (B), and (C) in the composition.

[0035] Starting material (D) Solvent The starting material (D) is an optional solvent that can be used in the compositions and methods described herein to facilitate the combination of starting materials A), B), and / or C) if present. The solvents used herein serve to fluidize the starting materials and do not substantially react with any of these starting materials. The solvent may be selected based on the solubility of the starting materials and the volatility of the solvent. "Solubility" means that the solvent is sufficient to dissolve and / or disperse the starting material. Volatility refers to the vapor pressure of the solvent. For example, the starting material (A) phosphonium catalyst can be dissolved in a solvent before combining the starting material (A) with the starting material (B) (and (C) if present). Alternatively, the starting material (B) can be dissolved in a solvent before combining it with the starting material (A) (and (C) if present), for example, when the starting material (B) is a viscous fluid such as gum or a solid at room temperature such as a resin. Alternatively, the starting material (C) can be dissolved in a solvent before combining it with the starting materials (A) and (B), for example, when the starting material (C) is a solid at room temperature such as a resin. The solvent can be used in any amount selected by one of ordinary skill in the art depending on various factors such as the selection of the starting materials (A), (B) (and (C) if present) and their solubility.

[0036] 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 can be a halogenated hydrocarbon such as chloroform, 1,1,1-trichloroethane, or methylene chloride. A single solvent or a combination containing two or more solvents may be used herein.

[0037] The amount of the solvent can vary depending on various factors, such as the type of solvent selected, as well as the amount and type of other starting materials selected. However, the amount of the solvent can be 0.1% by weight or more, or 2% by weight or more, based on the total weight of starting materials (A), (B), and (C). On the other hand, simultaneously, the amount of the solvent can be at most 99% by weight, or at most 50% by weight. Alternatively, the amount of the solvent can be 0.1% to 99% by weight, or 2% to 50% by weight, based on the total weight of (A) catalyst, (B) polyorganohydrogensiloxane, and (C) polyorganosiloxane compound in the composition.

[0038] The composition can contain (A) a phosphonium catalyst, and (B) a polyorganohydrogensiloxane (and (C) a polyorganosiloxane and / or (D) a solvent if present). Alternatively, the composition described herein can optionally further contain additional components. The optional additional components can be present at a concentration of 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or even 1% by weight or less, based on the weight of the composition. Alternatively, the optional additional components can be present at a concentration of 0 to 50% by weight, or 0 to 40% by weight, or 0 to 30% by weight, or 0 to 20% by weight, or 0 to 10% by weight, or 0 to 5% by weight, or 1% to 30% by weight.

[0039] Optional additional components Examples of possible optional components include one component, or a combination of two or more components, selected from the group consisting of pigments (e.g., carbon black, or titanium dioxide), fillers (metal oxides including SiO2) (typically at a concentration of 50 wt% or less based on the weight of the composition), moisture scavengers, optical brighteners, stabilizers (e.g., antioxidants, and UV stabilizers), and corrosion inhibitors. Alternatively, the composition may not contain one or a combination of two or more such additional components. In addition, the composition may contain water at 1 wt% or less, or 0.5 wt% or less, based on the weight of the composition. Alternatively, the composition may be water-free.

[0040] The compositions described herein may be free of transition metals. "Free of transition metals" means that the composition contains no, or an undetectable amount of, or only a negligible amount of, the metals of Groups 4 - 12 of the IUPAC Periodic Table of the Elements as of December 1, 2018, and that the composition does not gel after 24 hours at room temperature. Without being bound by theory, it is believed that transition metals can catalyze the reaction between Si - H moieties and Si - O moieties at undesirably low temperatures (e.g., <65 °C).

[0041] The compositions described herein may be free of Lewis bases. "Free of Lewis bases" means that the composition contains no, or only a negligible amount of, compounds or ionic species that can donate an electron pair to a phosphonium catalyst, and that the composition does not cure sufficiently to form a gel within 20 minutes when heated at 65 °C. For example, the composition may be free of Lewis bases selected from the group consisting of the following bases: PR 10 3, P(NR 10 2)3, NR 10 3, N(SiR 10 3) x R 10 3-x 、R 10 C(NR 10 )N、P(N - R 10)R 10 3. Guanidine (C(=NR 10 )(NR 10 2)2), amidine (R 10 C(=NR 10 )NR 10 2), phosphazene, and

Chemical formula

[0042] Method The above composition can be a one-component composition. The one-component composition contains the starting materials (A) and (B) in the same part. The composition can be prepared by a method including the step of combining the starting materials, i) (A) a phosphonium catalyst, (B) a polyorganohydrogensiloxane, and, if present, (C) a polyorganosiloxane, (D) a solvent, and / or the above optional additional components, thereby forming a mixture. The use of the starting material (D) a solvent can facilitate the combination of the starting materials (A), (B), and, if present, (C). For example, one or more of the starting materials (A), (B), and, if present, (C) can be dissolved in the solvent before being mixed with the other starting materials. Alternatively, the starting materials can consist essentially of the above starting materials (A) and (B) (and optionally (C) and / or (D)). Alternatively, the starting materials can consist of the above starting materials (A) and (B) (and optionally (C) and / or (D)).

[0043] Combining starting materials to form a mixture and preparing a polyorganohydrogensiloxane composition are carried out under conditions where it does not cure (e.g., the Si-H moiety from (B) polyorganohydrogensiloxane does not significantly react with the Si-O-Si moiety from ((B) polyorganohydrogensiloxane and / or (C) polyorganosiloxane)). These conditions may include, for example, mixing by any convenient means. Mixing may be carried out using conventional mixing devices such as a stirred batch kettle. Alternatively, when the polyorganosiloxane selected for starting material (C) and / or the polyorganohydrogensiloxane selected for starting material (B) is viscous or solid (e.g., gum or resin), mixing under shear can be carried out, for example, using an extruder. The composition can be formed, for example, by mixing the above starting materials (A) and (B). Starting materials (A) and (B) can be combined at a temperature below room temperature. Alternatively, the temperature for combining starting materials (A), (B), (and (C) and / or (D)) can be from 5°C to 30°C. Starting materials (A), (B), (and (C) and / or (D)) can be combined simultaneously. Alternatively, starting materials (A) and (B) (and (D) when present) can be combined to form a mixture, and then the mixture can be combined with starting material (C) (or its solvent solution), for example, by metering it over a period of time or adding it in one or more aliquots, to starting material (C) (and additional (D) when present).

[0044] Curing of the composition A method of curing a composition, the method comprising: 1) Providing the composition as described above; 2) heating the composition to a temperature sufficient to catalyze the reaction of silicon-bonded hydrogen atoms in (B) polyorganohydrogensiloxane, for example, the temperature in step 2) can be ≧ 65 °C. Alternatively, the temperature can be > 30 °C, but the reaction time may be longer at a lower temperature than at a higher temperature. The method for curing the composition may optionally further include additional steps. For example, the method may further include additional steps after step 1) and before step 2), and the additional steps include molding the composition or applying the composition onto a substrate.

Examples

[0045] These examples are provided to illustrate the present invention to those skilled in the art and should not be construed as limiting the scope of the present invention described in the claims. The starting materials used in these examples are listed in Table 1.

[0046]

Table 1

[0047] Reference Example 1 - General Procedure The reaction was carried out in an N2-filled glove box using a solvent dried over 4 Å molecular sieves. Except as specified in Table 1, all starting materials were obtained from commercial sources and used as received.

[0048] The catalyst stock solution was prepared as follows:

[0049] [(C6F5)3PF][B(C6F5)4] stock solution A: [(C6F5)3PF][B(C6F5)4] (2.2 mg) was dissolved in CH2Cl2 (5 mL) to obtain [(C6F5)3PF][B(C6F5)4] stock solution A (0.44 mg / mL).

[0050] [(C6F5)3PF][F] stock solution A’: [P(C6F5)3F+ F - (6.6 mg) was dissolved in CH2Cl2 (15 mL), and [P(C6F5)3F + F - Stock solution A’ (0.44 mg / mL) was obtained.

[0051] [(C6F5)3PF][B(C6F5)4]+NEt3 Stock solution A: Et3N was added in a 1:1 molar ratio with catalyst 1. The Et3N stock solution (49.9 μL of Et3N in 1 mL of CH2Cl2) was first added to the reaction mixture, followed by the catalyst stock solution A (0.44 mg / mL).

[0052] FAB Stock solution A: FAB (2.6 mg) was dissolved in CH2Cl2 (5.8 mL) to obtain FAB stock solution A (0.44 mg / mL).

[0053] Reference Example 2 - Setup and progress of the example reaction using catalyst 1 at room temperature D H x (1 mL, 0.98 g) was added to a 30 mL vial containing a magnetic stir bar. To this vial, 0.2 mL of the [(C6F5)3PF][B(C6F5)4] stock solution A (0.088 mg of [(C6F5)3PF][B(C6F5)4]) was added. The mixture was stirred at room temperature. The reaction was monitored at different time intervals to see if a gel was formed. Gel formation indicated crosslinking (hardening). No attempt was made to remove the hardened material from the vial. The results are shown in Table 2 below.

[0054] Reference Example 3 - Setup and progress of the comparative example reaction Reference Example 2 was repeated except that 0.2 mL of the FAB stock solution A (0.088 mg of FAB) was used. The results are shown in Table 2 below.

[0055] Reference Example 4 - Setup and progress of the comparative example reaction Reference Example 2 was repeated except that 0.2 mL of [(C6F5)3PF][B(C6F5)4] stock solution A (0.088 mg of [(C6F5)3PF][B(C6F5)4] + 0.2 mL of NEt3 stock solution (molar ratio 1:1 with Catalyst 1)) was used. The results are shown in Table 2 below.

[0056] Reference Example 5 - Setup and Progression of Comparative Example Reactions Reference Example 2 was repeated except that 0.2 mL of [(C6F5)3PF][F] stock solution A (0.088 mg of [(C6F5)3PF][F]) was used. The results are shown in Table 2 below.

[0057] Reference Example 6 - Setup and Progression of Example Reactions Using Catalyst 1 at 65 °C D H x (1 mL, 0.98 g) was added to a 30 mL vial containing a magnetic stir bar. To this vial, 0.5 mL of [(C6F5)3PF][B(C6F5)4] stock solution A (0.22 mg of [(C6F5)3PF][B(C6F5)4]) was added. The reaction was monitored at different time intervals to see if a gel formed. The solution was kept at room temperature overnight. Then, the solution was stirred at 65 °C via a preheated aluminum block. Gel formation indicated crosslinking (hardening). No attempt was made to remove the hardened material from the vial. The results are shown in Table 2 below.

[0058] Reference Example 7 - Setup and Progression of Comparative Example Reactions Reference Example 6 was repeated except that 0.5 mL of [(C6F5)3PF][B(C6F5)4] stock solution A (0.22 mg of [(C6F5)3PF][B(C6F5)4] + 0.5 mL of NEt3 stock solution (molar ratio 1:1 with Catalyst 1)) was used. The results are shown in Table 2 below.

[0059] Reference Example 8 - Setup and Progression of Comparative Example Reactions Reference Example 6 was repeated except that 0.5 mL of [(C6F5)3PF][F] stock solution A (0.22 mg of [(C6F5)3PF][F]) was used. The results are shown in Table 2 below.

[0060] [Table 2] 1 No gel was observed after 24 hours at room temperature. Then, the solution was left standing over a four-day weekend when no one was present, and it was observed that a gel had formed when the observation was resumed.

[0061] The data in Table 2 for Reference Examples 2 and 6 show that a one-component composition can be prepared that is stable (does not gel) for at least one day at room temperature using a phosphonium catalyst containing a tetravalent monocation of phosphorus and a non-coordinating anion, but cures in 20 minutes at a high temperature of 65°C. Reference Examples 4 and 7 showed that the presence of a Lewis base (triethylamine) hindered curing under the tested conditions. Reference Examples 5 and 8 showed that Catalyst 2 containing a strongly coordinating anion did not cure the composition when tested at 65°C. Reference Example 3 shows rapid curing at room temperature when FAB was used instead of the catalyst described herein. [Industrial Applicability]

[0062] The above composition is storage-stable, which means that the composition does not gel at room temperature for 1 hour or less, or 5 hours or less, or 24 hours or less, or 48 hours or less, or 36 hours or less. The compositions and methods described herein are useful for preparing and curing silicone compositions that cure to form products such as coatings, adhesives, elastomers, and foams. The inventors have surprisingly found that the catalysts described herein cure polyorganosiloxane compositions. Further, the inventors have surprisingly found that no Lewis base and / or crosslinking molecule is required to stabilize the catalysts described herein. In contrast, the presence of a Lewis base such as triethylamine can render the compositions of the present invention uncureable under the conditions tested in the above examples. The compositions and methods of the present invention provide polyorganohydrogensiloxane compositions that are storage-stable at room temperature and curable by heating to a moderate temperature.

[0063] Definition and Use of Terms The abbreviations used herein have the definitions in Table 3 below.

[0064]

Table 3

[0065] All amounts, ratios, and percentages are by weight unless otherwise indicated. The amounts of all starting materials in the composition total 100% by weight. The "Summary of the Invention" and "Abstract" are incorporated herein by reference. The articles "a", "an", and "the" each refer to one or more unless specifically indicated otherwise by the context of the specification. The singular form includes the plural unless otherwise stated.

[0066] The terms "comprising" and derivatives thereof, such as "comprise" and "comprises", mean "including", "include", "consist(ing) essentially of", and "consist(ing) of", and are used herein in their broadest sense to encompass. The use of "for example", "e.g.", "such as", and "including" to list examples is not limited to only the examples listed. Thus, "for example" or "such as" means "for example, but not limited to" or "such as, but not limited to", and encompasses other similar or equivalent examples.

[0067] Generally, the hyphen "-" or tilde "~" in a range of values as used herein means "to" or "through", ">" means "above" or "greater-than", "≧" means "at least" or "greater-than or equal to", "<" means "below" or "less-than", and "≦" means "at most" or "less-than or equal to".

[0068] Embodiments of the present invention In a first embodiment, the composition is as follows: (A) A phosphonium catalyst, which is from 1 ppm to 1,000 weight ppm based on the total weight of starting materials (A) and (B), and is as follows: (i) The formula [PR 1 3R 2 + ​A tetravalent monocation of phosphorus, where each R 1 is of the formula [Chemical formula] is an independently selected aryl halide group, where each R 8 is selected from Cl, F, or -CF3, and each R 2 is independently selected from Br, Cl, F, and -CF3, a tetravalent monocation of phosphorus, and (ii) A non-coordinating anion of the formula [BR 3 4] - where each R 3 is independently selected from the group consisting of a monovalent hydrocarbon group and a monovalent halogenated hydrocarbon group, a non-coordinating anion, including a phosphonium catalyst, and (B) A polydiorganohydrogensiloxane, which is 1 wt% to <100 wt% based on the total weight of starting materials (A), (B), and (C), as follows: Unit formula (B-1): (HR 4 2SiO 1 / 2 ) g (R 4 3SiO 1 / 2 ) h (R 4 2SiO 2 / 2 ) i (HR 4 SiO 2 / 2 ) j is a linear polydiorganohydrogensiloxane, where each R 4 is an independently selected monovalent hydrocarbon group that does not contain aliphatic unsaturation, and the subscripts g, h, i, and j are such that g≥0, h≥0, the quantity (g + h)=2, i≥0, j≥0, and the quantity (g + j)≥1, and the quantity (i + j)=0 to 2000, a linear polydiorganohydrogensiloxane, and Unit formula (B-2): (R 4 2SiO 2 / 2 ) u (R 4 HSiO 2 / 2 ) vA cyclic polydiorganohydrogensiloxane containing, wherein R 4 is as described above, the subscript u is 0 or more, the subscript v is 1 or more, and the quantity (u + v) is from 3 to 15, a cyclic polydiorganohydrogensiloxane, and (B-3) A mixture with a polydiorganohydrogensiloxane selected from the group consisting of both combinations of (B-1) and (B-2). Selected from the group consisting of Contains.

[0069] In a second embodiment, in the composition of the first embodiment, the (A) phosphonium catalyst has the formula [(C6F5)3PF] + [B(C6F5)4] - Have.

[0070] In a third embodiment, in the first embodiment or the second embodiment, the (B) polyorganohydrogensiloxane is (i) α,ω-dimethylhydrogensiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane), (ii) α,ω-dimethylhydrogensiloxy-terminated polymethylhydrogensiloxane, (iii) α,ω-trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane), (iv) α,ω-trimethylsiloxy-terminated polymethylhydrogensiloxane, and (v) α-dimethylhydrogensiloxy, ω-trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane), (vi) α-dimethylhydrogensiloxy, ω-trimethylsiloxy-terminated polymethylhydrogensiloxane, (vii) Combinations of two or more of these, Selected from the group consisting of

[0071] In the fourth embodiment, in any one of the compositions of the first to third embodiments, (C) polyorganosiloxane is selected from the group consisting of α,ω-trimethylsiloxy-terminated polydimethylsiloxane, α,ω-dimethylphenylsiloxy-terminated poly(dimethylsiloxane / methylphenylsiloxane), α,ω-dimethylphenylsiloxy-terminated polymethylphenylsiloxane, α,ω-trimethylsiloxy-terminated poly(dimethylsiloxane / methylphenylsiloxane), α,ω-trimethylsiloxy-terminated polymethylphenylsiloxane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and combinations of two or more thereof.

[0072] In the fifth embodiment, in any one of the compositions of the first to fourth embodiments, the composition further contains 1% to 99% by weight of (D) solvent based on the total weight of the composition.

[0073] In the sixth embodiment, any one of the compositions of the first to fifth embodiments is used to prepare a product selected from the group consisting of coatings, adhesives, elastomers, and foams.

[0074] In the seventh embodiment, any one of the compositions of the first to fifth embodiments is a curable system, and the method includes: i) adding the composition to a polyorganosiloxane formulation; and ii) curing the polyorganosiloxane formulation to form a product selected from the group consisting of coatings, adhesives, elastomers, and foams.

Claims

1. (A) (i) tetravalent monocation of phosphorus, and (ii) formula [BR ３ ４ ] － A phosphonium catalyst containing a non-coordinating anion, wherein each R ３ A composition comprising a mixture of a phosphonium catalyst, which is independently selected from the group consisting of monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups, and (B) a polyorganohydrogensiloxane, wherein the composition does not contain a Lewis base.

2. (i) The tetravalent monocation of phosphorus is a Lewis acidic phosphonium cation of the formula [PR １ ３ R ２ , wherein each R ＋ is independently selected from the group consisting of X', -CX' ２ , and -OR ３ , each X' is independently selected from the group consisting of Br, Cl, and F, R ９ is an alkyl group or an aryl group, and each R ９ is an independently selected aryl halide group. The composition according to claim 1.​​

3. (i) The tetravalent monocation of phosphorus is, 【Chemistry 2】 The composition according to claim 1, having the following characteristics.

4. (ii) The non-coordinating anion is of formula [BR ３ ４ ] － It has, in the formula, each R ３ The composition according to claim 1, wherein the group is an aryl halide.

5. (ii) The anion is of formula B(C ６ F ５ ) ４ － The composition according to claim 1, having the following characteristics.

6. (A) The phosphonium catalyst is of formula: 【Chemistry 2】 The composition according to claim 1, having the following characteristics.

7. (B) The polyorganohydrogensiloxane is HR ４ ２ SiO １／２ , R ４ ３ SiO １／２ , HR ４ SiO ２／２ , R ４ ２ SiO ２／２ , R ４ SiO ３／２ , HSiO ３／２ , and SiO ４／２ The formula includes two or more siloxane units selected from the group consisting of units, and each R ４ The composition according to claim 1, wherein the monovalent hydrocarbon group is independently selected and does not contain aliphatic unsaturated material.

8. (B) The polyorganohydrogensiloxane is as follows: (B-1) A linear polyorganohydrogensiloxane, with unit formula (HR ４ ２ SiO １／２ ) ｇ (R ４ ３ SiO １／２ ) ｈ (R ４ ２ SiO ２／２ ) ｉ (HR ４ SiO ２ ／２ ) ｊ Includes, in the formula, R ４ However, as stated above, the subscripts g, h, i, and j have values ​​such that g≧0, h≧0, quantity(g+h)=2, i≧0, j≧0, and quantity(g+j)≧1, and the quantity(i+j) is between 0 and 1,000, a linear polyorganohydrogensiloxane. (B-2) A cyclic polyorganohydrogensiloxane, with unit formula (R ４ ２ SiO ２／２ ) ｕ (R ４ HSiO ２／２ ) ｖ Includes, in the formula, R ４ However, as stated above, the subscript u is 0 or greater, the subscript v is 1 or greater, the quantity (u + v) is 3 to 15, and each R ４ However, a cyclic polyorganohydrogensiloxane is a monovalent hydrocarbon group that is independently selected, and (B-3) The combination of both (B-1) and (B-2), A composition according to claim 1, selected from the group consisting of the following.

9. (C) further comprising a polyorganosiloxane, (C) the polyorganosiloxane is R ４ ３ SiO １／２ , R ４ ２ SiO ２／２ , R ４ SiO ３／２ , and SiO ４／２ The formula contains two or more siloxane units selected from the units, and each R ４ The composition according to claim 1, wherein the monovalent hydrocarbon group is independently selected and does not contain aliphatic unsaturated material.

10. (C) The polyorganosiloxane is as follows: (C-1) A linear polydiorganosiloxane, with unit formula: (R ４ ３ SiO １／２ ) ２ (R ４ ２ SiO ２／２ ) ｘ Includes, in the formula, R ４ However, as stated above, 1,000 ≥ x ≥ 1, linear polydiorganosiloxane, (C-2) A cyclic polydiorganosiloxane, with unit formula: (R ４ ２ SiO ２／２ ) ｙ Includes, in the formula, R ４ However, as stated above, 15 ≥ y ≥ 3, cyclic polydiorganosiloxane, (C-3) A combination of both (C-1) and (C-2) Selected from the group consisting of, The composition according to claim 9.

11. The composition according to claim 1, wherein the amount of the phosphonium catalyst is 1 ppm to 1,000 ppm based on the weight of (B) the polyorganohydrogensiloxane and, if present, (C) the polyorganosiloxane.

12. (D) The composition according to claim 1, further comprising a solvent.

13. The composition according to claim 1, further comprising one or more combinations of components selected from the group consisting of pigments, fillers, moisture scavengers, fluorescent whitening agents, stabilizers, and corrosion inhibitors.

14. The composition according to claim 1, wherein the composition does not contain a transition metal.

15. It is a method, 1) A step of providing the composition according to any one of claims 1 to 14, 2) The step of heating the composition to a temperature sufficient to catalyze the reaction of silicon-bonded hydrogen atoms in the polyorganohydrogensiloxane (B), A method comprising optionally, after step 1) and before step 2), the step of molding the composition or applying the composition onto a substrate.

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