Polyorganohydrogensiloxane composition containing a Lewis acidic dicationic phosphonium salt

Abstract

A composition containing a phosphonium catalyst and a polyorganohydrogensiloxane. The composition is curable by a method including heating. This composition and method are useful for preparing polyorganosiloxane products such as coatings, adhesives, elastomers, and foams.

Description

Technical Field

[0001] (Cross - reference to related applications) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 352,317, filed on June 15, 2022, under 35 U.S.C. § 119(e). U.S. Provisional Patent Application No. 63 / 352,317 is incorporated herein by reference.

[0002] There are provided curable polyorganohydrogensiloxane compositions, and methods for their preparation and curing. More particularly, the curable polyorganosiloxane compositions include a Lewis acidic dicationic 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 a reaction 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 would be desirable to provide a one - component system with storage stability that utilizes the rearrangement reaction and is stable at room temperature but can be triggered to cure upon heating.

Summary of the Invention

[0004] The polyorganohydrogensiloxane composition (composition) comprises a mixture of (A) a phosphonium catalyst comprising (i) a tetravalent dication of phosphorus and (ii) a non-coordinating anion, and (B) a polyorganohydrogensiloxane. Methods for preparing and curing the composition are provided.

Mode for Carrying Out the Invention

[0005] The starting material (A) used herein is a phosphonium catalyst comprising (i) a tetravalent dication of phosphorus and (ii) a non-coordinating anion. The tetravalent dication of phosphorus is a Lewis acidic phosphorus dication of formula (i-1): [P(R 2 )(R 1 )] 2+ wherein each R 1 is independently selected from the group consisting of a monovalent hydrocarbon group and a monovalent halogenated hydrocarbon group, and R 2 is a divalent or trivalent heteroaryl group. The monovalent hydrocarbon group of R 1 can be an alkyl group or an aryl group. The monovalent halogenated hydrocarbon group of R 1 can be an alkyl group or an aryl group (introduced as above and described in detail below) in which one or more hydrogen atoms are replaced by F, Cl, Br, or I.

[0006] R 1 Suitable alkyl groups 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 chloromethyl, trifluoromethyl, and trifluoropropyl groups.

[0007] R 1 The aryl group suitable for R may be monocyclic or polycyclic and may have a pendant hydrocarbyl group. For example, for R 1 the aryl groups include phenyl, tolyl, xylyl, and naphthyl, and further include aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl. Alternatively, for R 1 the aryl group may be monocyclic such as phenyl, tolyl, or benzyl, or for R 1 the aryl group may be phenyl. Alternatively, for R 1 may be a halogenated aryl group such as chlorobenzyl. Alternatively, for R 1 the halogenated aryl group has the formula:

[0008]

Chemical formula

[0009] In formula (i-1), R 2 which is a divalent or trivalent heteroaryl group may be selected from the group consisting of bipyridine ligands and terpyridine ligands. The bipyridine ligand has the formula:

[0010]

Chemical formula

[0011] [Chemical formula] It may have. In the formulas of bipyridine ligands and terpyridine ligands, each R is independently selected from the group consisting of a hydrogen atom and a monovalent hydrocarbon group having 1 to 4 carbon atoms, for example, alkyl groups selected from methyl, ethyl, propyl (including n-propyl and isopropyl), and butyl (including n-butyl, isobutyl, sec-butyl, and t-butyl). Alternatively, each R may be H. Alternatively, each R may be t-butyl.

[0012] Alternatively, (i) the tetravalent dication of phosphorus is

[0013] [Chemical formula]

[0014] [Chemical formula] It may have a formula selected from the group consisting of

[0015] (A) In the phosphonium catalyst, (ii) the anion is a non-coordinating anion. The non-coordinating anion has 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 a monovalent hydrocarbon group (as exemplified above for R 1 ) and a monovalent halogenated hydrocarbon group (as exemplified above for R 1 ).

[0016] 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. A completely saturated anion may have the formula [BR 3 4] - , where 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 as described above. Alternatively, the anion may have the formula [B(C6F5)4] - .

[0017] Alternatively, (A) the phosphonium catalyst may have the formula [P(R 1 )(R 2 )] 2+ [BR 3 4]2 - , where R 1 , R 2 , and R 3 are as described above. Alternatively, (A) the catalyst may have a formula selected from the following:

[0018]

Chemical formula

[0019]

Chemical formula

[0020] The starting material (A), the phosphonium catalyst, can be prepared by methods known to those skilled in the art, such as by varying appropriate starting materials as disclosed in Catalytic Hydrodefluorination of C-F Bonds by an Air-Stable P III Lewis Acid by Chitnis, et al, Chem. Eur. J. 2018, 24, 6543 - 6546. The starting material (A) can be any one of the above catalysts or a combination of two or more of the above catalysts.

[0021] The compositions described herein contain (A) a phosphonium catalyst in an amount sufficient to cure the composition. The exact amount of the (A) phosphonium catalyst depends on various factors, including the selection of (B) a polyorganohydrogensiloxane, its SiH content, and whether (C) a (non-functional) polyorganosiloxane is present. However, the composition may contain a catalyst sufficient to provide a concentration of a tetravalent dication of phosphorus that is 100 parts per million (ppm) or more, 1 ppm or more, 1,000 ppm or more, 5,000 ppm or more, 10,000 ppm or more, 20,000 ppm or more, 30,000 ppm or more, 40,000 ppm or more, 50,000 ppm or more per million parts by weight. On the other hand, it can simultaneously be 100,000 ppm or less, 90,000 ppm or less, 80,000 ppm or less, 70,000 ppm or less, or 60,000 ppm or less, each based on the weight of (B) the polyorganohydrogensiloxane and, if present, (C) the (non-functional) polyorganosiloxane in the composition. Alternatively, the amount of the catalyst can be 100 ppm to 100,000 ppm, or 10,000 ppm to 90,000 ppm, or 20,000 ppm to 80,000 ppm, or 30,000 ppm to 70,000 ppm, or 50,000 ppm to 60,000 ppm.

[0022] Starting material (B) polyorganohydrogensiloxane The compositions described herein further contain (B) a polyorganohydrogensiloxane. The polyorganohydrogensiloxane can include 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 a rearrangement reaction of both the Si-H moieties and the Si-O-Si moieties within the (B) polyorganohydrogensiloxane to cure the composition.

[0023] Polyorganohydrogensiloxane has at least one Si-H moiety per molecule. Alternatively, polyorganohydrogensiloxane may 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.

[0024] 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.

[0025] Alternatively, (B) polyorganohydrogensiloxane can be linear or cyclic. For example, (B) 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 ) j which contains, 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, at the same time, 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, g 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.

[0026] Polydiorganohydrogensiloxanes suitable for use herein are exemplified by the following: (i) α,ω-dimethylhydrogensiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane), (ii) α,ω-dimethylhydrogen siloxy-terminated polymethylhydrogen siloxane, (iii) α,ω-trimethylsiloxy-terminated poly(dimethylsiloxane / methylhydrogen siloxane), (iv) α,ω-trimethylsiloxy-terminated polymethylhydrogen siloxane, 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.

[0027] Alternatively, the polyorganohydrogen siloxane can be cyclic. For example, (B) the polyorganohydrogen siloxane can be a cyclic polydiorganohydrogen siloxane and 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. On the other hand, simultaneously, 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. On the other hand, simultaneously, 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 4may be methyl. Examples of cyclic polyorganohydrogensiloxanes include (i) trimethylcyclotrisiloxane, (ii) tetramethylcyclotetrasiloxane, (iii) pentamethylcyclopentasiloxane, (iv) hexamethylcyclohexasiloxane, and (v) combinations of two or more thereof.

[0028] 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 methylhydrogensiloxane dimethylsiloxane 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-functionalized), and HPM-502 (phenyl-functionalized). 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.

[0029] The amount of (B) polyorganohydrogensiloxane in the composition depends on various factors, including the Si-H content of the polyorganosiloxane and whether there is a (C) polyorganosiloxane that does not contain Si-H moieties. 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.

[0030] Alternatively, in addition to (B) polyorganohydrogensiloxane, the composition may further contain a (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.

[0031] Starting material (C) polyorganosiloxane Starting material (C) is an optional polyorganosiloxane that does not contain Si-H moieties. The polyorganosiloxane contains two or more siloxane units selected from R 4 3SiO 1 / 2 、R 4 2SiO 2 / 2 、R 4 SiO 3 / 2 、and SiO 4 / 2 units. In the formula, each R4 is an independently selected monovalent hydrocarbon group that does not contain aliphatic unsaturation. The monovalent hydrocarbon group that does not contain aliphatic unsaturation can be an alkyl group or an aryl group.

[0032] R 4 Suitable alkyl groups for R

[0033] R 4 Suitable aryl groups for R 3 can be monocyclic or polycyclic and can have pendant hydrocarbyl groups. For example, aryl groups for R4 The aryl group of can be monocyclic such as phenyl, tolyl, or benzyl, or alternatively, R 4 's aryl group can be phenyl. R 4 's halogenated aryl group has the formula:

[0034]

Chemical formula

[0035] 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 ) x and in the formula, R 4is 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, at the same time, 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.

[0036] 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.

[0037] 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).

[0038] Alternatively, (C) the polydiorganosiloxane has the unit formula (C-2): (R 4 2SiO 2 / 2 ) yIt can be a cyclic polydiorganosiloxane containing, wherein R 4 is as described 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.

[0039] 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).

[0040] 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.

[0041] 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" refers to the solvent being 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.

[0042] 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.

[0043] The amount of the solvent can vary depending on various factors such as the type of the selected solvent, 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, at the same time, the amount of the solvent can be up to 99% by weight, or up to 50% by weight. Alternatively, the amount of the solvent can be from 0.1% by weight to 99% by weight, or from 2% by weight to 50% by weight, based on the total weight of (A) catalyst, (B) polyorganohydrogensiloxane, and (C) polyorganosiloxane compound in the composition.

[0044] The composition may 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 may optionally further contain additional components. The optional additional components may 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 may 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% by weight to 30% by weight.

[0045] Optional additional components Examples of possible optional components include one component 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, or a combination of two or more components. Alternatively, the composition may not include one or a combination of two or more such additional components. Additionally, 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.

[0046] 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 an insufficient amount of, metals of Groups 4 - 12 of the IUPAC Periodic Table 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).

[0047] The compositions described herein may be free of Lewis bases. "Free of Lewis bases" means that the composition contains no, or only an insufficient 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 - R10 )R 10 3. Guanidine (C(=NR 10 )(NR 10 2)2), amidine (R 10 C(=NR 10 )NR 10 2), phosphazene, and

[0048]

Chemical formula

[0049] Method The above composition can be a one-component composition. A one-component composition contains starting materials (A) and (B) in the same part. The composition can be prepared by a method including the step of combining starting materials including 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. Using the starting material (D) solvent can facilitate the combination of starting materials (A), (B), and, if present, (C). For example, one or more of starting materials (A), (B), and, if present, (C) can be dissolved in the solvent before being mixed with 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)).

[0050] 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 and the Si-O-Si moiety from ((B) polyorganohydrogensiloxane and / or (C) polyorganosiloxane) do not react significantly). These conditions may include, for example, mixing by any convenient means. Mixing may be carried out using a conventional mixing device 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) if present) can be from 5 °C to 30 °C. Starting materials (A), (B), (and (C) and / or (D) if present) can be combined simultaneously. Alternatively, starting materials (A) and (B) (and (D) if 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 over a period of time or by adding in one or more aliquots, with starting material (C) (and additional (D) if present).

[0051] 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 can be longer at a lower temperature than at a higher temperature. The method for curing the composition can optionally further include additional steps. For example, the method can 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

[0052] 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.

[0053]

Table 1

[0054]

Chemical formula

[0055] 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.

[0056] A stock solution of Catalyst 1 was prepared as follows: [terpyPPh][B(C6F5)4] (56 mg) was dissolved in CH2Cl2 (1 mL) to obtain a 56 mg / mL solution.

[0057] The stock solution of FAB was prepared as follows: FAB (2.6 mg) was dissolved in CH2Cl2 (5.8 mL) to obtain FAB stock solution A (0.44 mg / mL).

[0058] Reference Example 2 - Setup and Progression of the Reaction D H x (1 mL, 0.98 g) was added to a 30 mL vial containing a magnetic stir bar. To this vial, 1 mL of catalyst 1 stock solution (56 mg of [terpyPPh][B(C6F5)4]) was added. The resulting solutions were stirred at 65 °C via a preheated aluminum block. 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.

[0059] Reference Example 3 - Setup and Progression of the Comparative Example Reaction Reference Example 2 was repeated except that 0.2 mL of FAB stock solution (0.088 mg of FAB) was used. The results are shown in Table 2 below.

[0060]

Table 2

Industrial Applicability

[0061] The above composition is storage stable, which means that the composition does not gel at room temperature for 0.5 hours or less, or 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 uncurable 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.

[0062] Definition and Use of Terms The abbreviations used herein have the definitions in Table 3 below.

[0063]

Table 3

[0064] All amounts, ratios, and percentages are by weight unless otherwise indicated. The amounts of all starting materials in the composition total 100 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.

[0065] The term "comprising" and its derivatives, 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" for listing 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.

[0066] Generally, the hyphen "-" or tilde "~" in a range of values 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".

[0067] Embodiments of the present invention In a first embodiment, the composition is as follows: (A) A phosphonium catalyst, which is from 100 ppm to 100,000 ppm based on the total weight of starting materials (A) and (B), and is as follows: (i) [P(R 2 )(R 1 )] 2+A tetravalent dications of phosphorus, wherein R 1 is an aryl group, and R 2 is a bidentate pyridine ligand or a terpyridine ligand, a tetravalent dication of phosphorus, and (ii) A non-coordinating anion of the formula [BR 3 4] - wherein each R 3 is an independently selected aryl halide group, a non-coordinating anion, and a phosphonium catalyst, (B) A polydiorganohydrogensiloxane, which is 1% to <100% by weight 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 A linear polydiorganohydrogensiloxane of the formula, wherein 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 ) v A cyclic polydiorganohydrogensiloxane containing, 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 3 to 15, a cyclic polydiorganohydrogensiloxane, and (B-3) A combination of both (B-1) and (B-2) Selected from the group consisting of and includes a mixture with polydiorganohydrogensiloxane.

[0068] In a second embodiment, in the composition of the first embodiment, the (A) phosphonium catalyst

[0069] [Chemical formula] contains.

[0070] In a third embodiment, in the composition of the first embodiment or the second embodiment, the (B) polyorganohydrogensiloxane (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) a combination of two or more of these selected from the group consisting of.

[0071] In a fourth embodiment, in the composition of the first embodiment or the second embodiment, the (B) polyorganohydrogensiloxane is selected from the group consisting of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and combinations of two or more of these.

[0072] In the fifth 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.

[0073] 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.

[0074] 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.

[0075] 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 composition comprising a mixture of (A) a phosphonium catalyst comprising (i) a Lewis acidic phosphorus cation of phosphorus and (ii) a non-coordinating anion, and (B) a polyorganohydrogensiloxane.

2. (i) the Lewis acidic phosphorus dication of phosphorus has the formula [P(R ２ ) (R １ ) ] ２＋ wherein each R １ is independently selected from the group consisting of monovalent hydrocarbon groups, and monovalent halogenated hydrocarbon groups; R ２ The composition of claim 1 , wherein is a divalent or trivalent heteroaryl group.

3. R ２ is the formula 【Chemical Formula 1】 selected from the group consisting of terpyridine ligands of and bipyridine ligands of the formula 【Chemical 2】 wherein each R is independently selected from the group consisting of a hydrogen atom and an alkyl group of 1 to 6 carbon atoms, the composition according to claim 2.

4. The composition according to claim 3, wherein each R is selected from the group consisting of H and tert-butyl.

5. R ２ is 【Chemical Formula 3】 【Chemical 4】 selected from the group consisting of, the composition according to claim 4.

6. (ii) the non-coordinating anion has the formula [BR ３ ４ －， and in the formula, each R ３ is independently selected from the group consisting of monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups, the composition according to any one of claims 1 to 5.

7. (ii) The non-coordinating anion is of the formula [B(C ６ F ５ ) ４ ] － The composition according to claim 6, having

8. (A) The phosphonium catalyst has the formula: [Chemical Formula 5] [[Chemical Formula 6]] The composition according to claim 7.

9. (B) The polyorganohydrogensiloxane is HR ４ 2SiO 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 units, and contains two or more siloxane units selected from the group consisting of, wherein each R ４ is an independently selected monovalent hydrocarbon group that does not contain aliphatic unsaturation. The composition according to any one of claims 1 to 8.

10. (B) The polyorganohydrogensiloxane is as follows: (B-1) A linear polyorganohydrogensiloxane having the 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 and wherein R ４ is as defined above, and the subscripts g, h, i, and j have values 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) is from 0 to 1,000, a linear polydiorganohydrogensiloxane, (B-2) A cyclic polyorganohydrogensiloxane having a unit formula (R ４ ２ SiO ２／２ ) ｕ (R ４ HSiO ２／２ ) ｖ wherein the subscript u is 0 or more, the subscript v is 1 or more, the quantity (u + v) is 3 to 15, and each R is an independently selected monovalent hydrocarbon group, a cyclic polydiorganohydrogensiloxane (B-3) A combination of both (B-1) and (B-2) selected from the group consisting of The composition according to claim 9.

11. (C) further comprises a polyorganosiloxane, and (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 units, and contains two or more siloxane units selected from the group consisting of, wherein each R ４ is an independently selected monovalent hydrocarbon group that does not contain aliphatic unsaturation. The composition according to any one of claims 1 to 10.

12. (C) The polyorganosiloxane is as follows: (C-1) A linear polydiorganosiloxane having a unit formula: (R ４ ３ SiO １／２ ) ２ (R ４ ２ SiO ２／２ ) ｘ wherein R ４ is as defined above and 1,000 ≥ x ≥ 1, a linear polydiorganosiloxane, (C-2) cyclic polydiorganosiloxane having a unit formula: (R ４ ２ SiO ２／２ ), ｙ wherein R ４ is as defined above and 15 ≥ y ≥ 3, a cyclic polydiorganosiloxane, (C-3) A combination of both (C-1) and (C-2) selected from the group consisting of The composition according to claim 11.

13. The composition according to any one of claims 1 to 12, further comprising (D) a solvent.

14. The composition according to any one of claims 1 to 13, wherein the composition does not contain a transition metal.

15. A method comprising: 1) providing a composition according to any one of claims 1 to 14; 2) heating the composition to a temperature sufficient to catalyze the reaction of the silicon-bonded hydrogen atoms in (B) the polyorganohydrogensiloxane; Optionally, the method may further comprise an additional step after step 1) and before step 2), the additional step comprising molding the composition or applying the composition onto a substrate.

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