Polyorganohydrosiloxane compositions comprising lewis acidic dicationium phosphonium salts

Abstract

A composition containing a phosphonium catalyst and a polyorganohydrosiloxane is provided. The composition may be cured in a process including heating. The compositions and methods are useful for preparing polyorganosiloxane products, such as coatings, adhesives, elastomers, and foams.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Serial No. 63 / 352,317, filed on June 15, 2022. U.S. Provisional Patent Application Serial No. 63 / 352,317 is hereby incorporated by reference. Technical Field

[0003] Provided are a curable polyorganohydrogensiloxane composition and a preparation and curing method thereof. More specifically, the curable polyorganohydrogensiloxane composition comprises a Lewis acidic dicationic phosphonium salt (catalyst) and a polyorganohydrogensiloxane. Background Art

[0004] It has been discovered that silyl hydride (Si-H) and siloxane bonds (Si-O-Si) undergo a rearrangement reaction in the presence of a strong Lewis acid, wherein the silicon from the siloxane bond combines with the hydrogen of the silyl hydride, and the silicon of the silyl hydride combines with the oxygen of the siloxane bond. The silyl hydride and siloxane bonds participating in the rearrangement reaction may be on the same molecule or may be on different molecules. The rearrangement reaction tends to be rapid in the presence of a strong Lewis acid. This reaction can be used to rapidly cure systems containing Si-H and siloxane bonds without the need for water or moisture. However, it requires a two-part system for storage, wherein the Lewis acid catalyst is kept away from the combination of the silyl hydride and siloxane bonds until the time of curing is required. It is desirable to be able to provide a shelf-stable one-component system that utilizes a rearrangement reaction that is shelf-stable at room temperature but can be triggered to cure by heating. Summary of the invention

[0005] A polyorganohydrogensiloxane composition (composition) comprising 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. DETAILED DESCRIPTION

[0006] 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+ , where each R 1 are 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. 1 , the monovalent hydrocarbon group may be an alkyl group or an aryl group.1 The monovalent halohydrocarbyl group may be an alkyl group or an aryl group in which one or more hydrogen atoms have been replaced by F, Cl, Br or I (as described above and in detail below).

[0007] Applicable to R 1 The alkyl group of can be linear, branched, cyclic or a combination of two or more thereof. Examples of alkyl groups include 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 isomers with 5 to 18 carbon atoms), and examples of alkyl groups also include cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. Suitable haloalkyl groups include chloromethyl, trifluoromethyl and trifluoropropyl.

[0008] Applicable to R 1 The aryl group may be monocyclic or polycyclic and may have a pendant hydrocarbon group. 1 The aryl groups of include phenyl, tolyl, xylyl and naphthyl, and also include aralkyl groups such as benzyl, 1-phenylethyl and 2-phenylethyl. 1 The aryl group may be monocyclic, such as phenyl, tolyl or benzyl; alternatively, R 1 The aryl group of may be phenyl. 1 It may be a halogenated aryl group, such as chlorobenzyl. 1 The haloaryl group may have the formula: Each R 8 independently selected from H, X and a group of formula -CX3, wherein each X is an independently selected halogen; provided that at least one R 8 is not H. Each X may be independently selected from chlorine (Cl) or fluorine (F). Alternatively, each X may be F. Alternatively, each R 8 may be independently selected from the group consisting of H, Cl, F and a group of formula -CF3, provided that at least one R 8 It is Cl, F or -CF3.

[0009] In formula (i-1), the divalent or trivalent heteroaryl group R 2 The ligand may be selected from the group consisting of bipyridine ligands and terpyridine ligands. The bipyridine ligand may have the formula: The terpyridine ligand may have the formula: In the formula of the bipyridine ligand and the terpyridine ligand, each R is independently selected from the group consisting of: a hydrogen atom and a monovalent hydrocarbon group of 1 to 4 carbon atoms, for example, an alkyl group selected from methyl, ethyl, propyl (including n-propyl and isopropyl) and butyl (including n-butyl, isobutyl, sec-butyl and tert-butyl). Alternatively, each R may be H. Alternatively, each R may be tert-butyl.

[0010] Alternatively, the (i) tetravalent dication of phosphorus may have a formula selected from the group consisting of:

[0011]

[0012] In the (A) phosphonium catalyst, (ii) the anion is a non-coordinating anion. The non-coordinating anion may have a charge that is delocalized on the surface of the anion, rather than being localized at a specific atom. Suitable non-coordinating anions include those of the formula [CF3SO3] - The trifluoromethanesulfonate (trifluoromethanesulfonate) and the formula [BR 3 4] - anion, where each R 3 Independently selected from the group consisting of: monovalent hydrocarbon groups (as described above for R 1 and exemplified) and monovalent halogenated hydrocarbon groups (such as those described above for R 1 described and exemplified).

[0013] Alternatively, the non-coordinating anion may be fully saturated, with no free valence electrons participating in forming covalent or coordination bonds with the phosphonium. A fully saturated anion may have 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, as described above. 3 may be a halogenated aryl group, as described above. Alternatively, (ii) the anion may have the formula [B(C6F5)4] - .

[0014] Alternatively, the (A) phosphonium catalyst may have the formula [P(R 1 )(R 2 )] 2+ [BR 3 4]2 - , where R 1 , R 2 and R 3 As described above. Alternatively, the (A) catalyst may have a formula selected from the following:

[0015]

[0016] The starting material (A), the phosphonium catalyst, can be prepared by methods known in the art, such as those described in "Preparation of P-type catalysts stabilized by air" by Chitnis et al., Chem. Eur. J. 2018, 24, 6543-6546. III Catalytic Hydrodefluorination of CF Bonds by an Air-Stable P III Lewis Acid)" by changing the appropriate starting material. The starting material (A) can be any one of the above catalysts, or a combination of two or more of the above catalysts.

[0017] The compositions described herein contain a sufficient amount of (A) phosphonium catalyst to cure the composition. The exact amount of (A) phosphonium catalyst depends on various factors, including the choice of (B) polyorganohydrogensiloxane, SiH content and the presence or absence of (C) (non-functional) polyorganosiloxane. However, the composition may contain sufficient catalyst to provide a tetravalent dianion concentration of phosphorus of 100 parts per million by weight (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; while at the same time having a tetravalent dianion concentration of phosphorus of 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; based on the weight of the (B) polyorganohydrogensiloxane and, when present, the (C) (non-functional) polyorganosiloxane in the composition. Alternatively, the amount of catalyst may be from 100 ppm to 100,000 ppm; alternatively from 10,000 ppm to 90,000 ppm; alternatively from 20,000 ppm to 80,000 ppm; alternatively from 30,000 ppm to 70,000 ppm; alternatively from 50,000 ppm to 60,000 ppm.

[0018] Starting material (B) polyorganohydrogensiloxane

[0019] The composition described herein also comprises (B) a polyorganohydrogensiloxane. The polyorganohydrogensiloxane may comprise both Si-H and Si-O-Si moieties. Thus, the composition comprising (A) a phosphonium catalyst and (B) a polyorganohydrogensiloxane may cure upon heating to form a gel without the need for additional components. Without being bound by theory, it is believed that the (A) phosphonium catalyst catalyzes the rearrangement reaction of both the Si-H and Si-O-Si moieties within the (B) polyorganohydrogensiloxane to cure the composition.

[0020] The polyorganohydrogensiloxane has at least one Si-H moiety per molecule. Alternatively, the polyorganohydrogensiloxane may have more than one Si-H moiety per molecule, such as 2 Si-H moieties per molecule or 3 Si-H moieties per molecule, or even more.

[0021] The polyorganohydrogensiloxane may include 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 Units consisting of two or more siloxane units; wherein each R 4 is an independently selected monovalent hydrocarbon group free of aliphatic unsaturated groups; provided that at least one unit per molecule contains a Si-H moiety (i.e., there is HR in the polyorganohydrogensiloxane 4 2SiO 1 / 2 , HR 4 SiO 2 / 2 and HSiO 3 / 2 The monovalent hydrocarbon group without aliphatic unsaturated groups may 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 may be independently selected from the group consisting of methyl and phenyl. Alternatively, each R 4 It may be methyl.

[0022] Alternatively, (B) polyorganohydrogensiloxane may be linear or cyclic. For example, (B) polyorganohydrogensiloxane may be a polyorganohydrogensiloxane comprising 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, wherein R 4As described above, and the values ​​of the subscripts g, h, i, and j are such that g≥0, h≥0, the amount (g+h)=2, i≥0, j≥0, and the amount (g+j)≥1, and the amount (i+j) is 0 to 2,000. The amount (i+j) may be 2,000 or less, alternatively 1,000 or less, alternatively 750 or less, alternatively 500 or less, alternatively 250 or less, alternatively 100 or less, and alternatively 50 or less; while at the same time, the amount (i+j) 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, alternatively 10 or more, alternatively 15 or more, alternatively 20 or more. Alternatively, (i+j) may be 0 to 1,000; alternatively 1 to 500; alternatively 2 to 250, and alternatively 3 to 100. Alternatively, (i+j) may be 1 to 100. Alternatively, (i+j) may be 2 to 50. Alternatively, (i+j) may be 5 to 25. Alternatively, when g=0 and h=2, j≥1 (alternatively ≥2). Alternatively, g may be 1, and h may be 1. Alternatively, g may be 2, and h may be 0. Alternatively, i may be 0 to 5, alternatively 1 to 4, alternatively 2 to 4, and alternatively 3 to 3.5. Alternatively, i may be 5 to 25. Alternatively, j may be 1 to 10, alternatively 2 to 9, alternatively 3 to 8, alternatively 4 to 7, and alternatively 5 to 6. Alternatively, when g>0, then j may be 0.

[0023] Examples of linear polydiorganohydrogensiloxanes suitable for use herein are:

[0024] (i) α,ω-dimethylhydrogensiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane),

[0025] (ii) α,ω-dimethylhydrogensiloxy-terminated polymethylhydrogensiloxane,

[0026] (iii) α,ω-trimethylsilyloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane),

[0027] (iv) α,ω-trimethylsilyloxy-terminated polymethylhydrogensiloxane, and

[0028] (v) poly(dimethylsiloxane / methylhydrogensiloxane) terminated with α-dimethylhydrogensiloxy-ω-trimethylsiloxy,

[0029] (vi) polymethylhydrogensiloxane terminated with α-dimethylhydrogensiloxy-ω-trimethylsiloxy,

[0030] (vii) a combination of two or more thereof.

[0031] Alternatively, the polyorganohydrogensiloxane may be cyclic. For example, the (B) polyorganohydrogensiloxane may be a cyclic polydiorganohydrogensiloxane, which may include unit formula (B-2): (R 4 2SiO 2 / 2 ) u (R 4 HSiO 2 / 2 ) v , where R 4 As described above, the subscript u is 0 or greater, the subscript v is 1 or greater, and the amount (u+v) is 3 to 15. Alternatively, u may be 0. Alternatively, u may be 0 or greater, alternatively 1 or greater, alternatively 2 or greater, alternatively 3 or greater; at the same time, u may be at most 6, alternatively at most 5, and alternatively at most 4. Alternatively, u may be 0 to 6, alternatively 0 to 4, alternatively 0 to 2, and alternatively 1 to 6. Alternatively, v may be 1 or greater, alternatively 2 or greater, alternatively 3 or greater, and alternatively 4 or greater; at the same time, v may be 12 or less, alternatively 10 or less, alternatively 8 or less, alternatively 6 or less, and alternatively 5 or less. Alternatively, v may have an average value of 4. Alternatively, v may be 1 to 12, alternatively 2 to 10, alternatively 3 to 8, alternatively 3 to 6, and alternatively 3 to 5. In unit formula (B-2), each R 4 Examples of the cyclic polyorganohydrogensiloxane include (i) trimethylcyclotrisiloxane, (ii) tetramethylcyclotetrasiloxane, (iii) pentamethylcyclopentasiloxane, (iv) hexamethylcyclohexasiloxane, and (v) a combination of two or more thereof.

[0032] Suitable polyorganohydrogensiloxanes are known in the art and are commercially available. For example, DOWSIL TM 6-3570 polymer, DOWSIL TM SH 1107 Fluid and XIAMETER TMMHX-1107 fluid is 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 Gallester include HMS-H271, HMS-071, HMS-993; HMS-301 and HMS-301R, HMS-991, HMS-993, HMS-082, HMS-151, HMS-013, HMS-053, HAM-301 (which is octyl functional) and HPM-502 (which is phenyl functional). Methods for preparing linear and branched polyorganohydrogensiloxanes suitable for use herein, such as hydrolysis and condensation of organohalosilanes, are well known in the art, as exemplified in U.S. Pat. Nos. 3,957,713 to Jeram et al.; 4,329,273 to Hardman et al.; 4,370,358 to Hayes et al.; 4,707,531 to Shirahata; 5,310,843 to Morita; and 2,823,218 to Speier et al., which disclose organohydrogensiloxane oligomers and linear polymers, as well as cyclic polymethylhydrogensiloxanes.

[0033] The amount of (B) polyorganohydrogensiloxane in the composition depends on various factors, including the Si-H content of the polyorganosiloxane and whether (C) polyorganosiloxane containing no Si-H moieties is present. However, the amount of polyorganohydrogensiloxane may be 1 wt% or more, alternatively 5 wt% or more, alternatively 10 wt% or more, alternatively 20 wt% or more, alternatively 30 wt% or more, alternatively 40 wt% or more, alternatively 50 wt% or more, alternatively 60 wt% or more, alternatively 70 wt% or more, alternatively 80 wt% or more, alternatively 90 wt% or more, alternatively 95 wt% or more, alternatively 99 wt% or more, while at the same time the amount of polyorganohydrogensiloxane may be <100 wt%, alternatively 99.9 wt% or less, alternatively 99.5 wt% or less, alternatively 99.1 wt% or less, alternatively 95 wt% or less, alternatively 90 wt% or less, alternatively 85 wt% or less, alternatively 80 wt% or less; each based on the combined weight of starting materials (A), (B) and (C) in the composition. Alternatively, the amount of polyorganohydrogensiloxane may be 1 wt% to <100 wt%, alternatively 5 wt% to <100 wt%, alternatively 10 wt% to 99.9 wt%, based on the same basis.

[0034] Alternatively, the composition may further include, in addition to (B) the polyorganohydrogensiloxane, (C) a polyorganosiloxane containing no Si-H moieties, which may serve as a source of Si-O-Si moieties in the curing reaction of the composition.

[0035] Starting material (C) polyorganosiloxane

[0036] The starting material (C) is an optional polyorganosiloxane containing no Si-H moieties. The polyorganosiloxane comprises a 4 3SiO 1 / 2 , R 4 2SiO 2 / 2 , R 4 SiO 3 / 2 and SiO 4 / 2 two or more siloxane units of units; wherein each R 4 is an independently selected monovalent hydrocarbon group free of aliphatic unsaturated groups. The monovalent hydrocarbon group free of aliphatic unsaturated groups may be an alkyl group or an aryl group.

[0037] Applicable to R 4The alkyl group of can be linear, branched, cyclic or a combination of two or more thereof. Examples of alkyl groups include 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 isomers having 5 to 18 carbon atoms), and examples of alkyl groups include cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. Suitable haloalkyl groups include chlorinated alkyl groups such as chloromethyl and chloropropyl groups; 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, 2,3-dichlorocyclopentyl; and fluorinated cycloalkyl groups such as 2,2-difluorocyclopropyl, 2,3-difluorocyclobutyl, 3,4-difluorocyclohexyl and 3,4-difluoro-5-methylcycloheptyl.

[0038] Applicable to R 4 The aryl group may be monocyclic or polycyclic and may have a pendant hydrocarbon group. 3 The aryl groups of include phenyl, tolyl, xylyl and naphthyl, and also include aralkyl groups such as benzyl, 1-phenylethyl and 2-phenylethyl. 4 The aryl group may be monocyclic, such as phenyl, tolyl or benzyl; alternatively, R 4 The aryl group of R may be phenyl. 4 The halogenated aryl group may have the formula: Each R 8 independently selected from H, X and a group of formula -CX3, wherein each X is an independently selected halogen; provided that at least one R 8 is not H. Each X may be independently selected from Cl or F. Alternatively, each X may be F. Alternatively, each R 8 may be independently selected from the group consisting of H, Cl, F and a group of formula -CF3, provided that at least one R 8 is Cl, F or -CF3. Alternatively, each R 4 Can be an independently selected alkyl group. Alternatively, each R 4 may be independently selected from the group consisting of methyl and phenyl. Alternatively, each R 4 It may be methyl.

[0039] The starting material (C) polyorganosiloxane may be a polydiorganosiloxane, which may be linear or cyclic. For example, the starting material (C) may be a polydiorganosiloxane comprising the unit formula (C-1): (R 4 3SiO 1 / 2 )2(R 4 2SiO 2 / 2 ) x A linear polydiorganosiloxane, wherein R 4 As described above, and 1,000 ≥ x ≥ 1. Alternatively, the subscript x may be at least 1, alternatively at least 2, alternatively at least 3, alternatively at least 5, alternatively at least 10, alternatively at least 25; at the same time, the subscript x may be at most 1,000, alternatively at most 500, alternatively at most 250, alternatively at most 100, and alternatively at most 50. Alternatively, the subscript x may have a value such that 500 ≥ x ≥ 1, alternatively 250 ≥ x ≥ 2, alternatively 100 ≥ x ≥ 5, alternatively 50 ≥ x ≥ 10, and alternatively 50 ≥ x ≥ 25.

[0040] Examples of linear polydiorganosiloxanes suitable for use herein are:

[0041] (i) α,ω-trimethylsilyloxy-terminated polydimethylsiloxane,

[0042] (ii) α,ω-dimethylphenylsiloxy-terminated poly(dimethylsiloxane / methylphenylsiloxane),

[0043] (iii) α,ω-dimethylphenylsiloxy-terminated polymethylphenylsiloxane,

[0044] (iv) α,ω-trimethylsilyloxy-terminated poly(dimethylsiloxane / methylphenylsiloxane),

[0045] (v) α,ω-trimethylsilyloxy-terminated polymethylphenylsiloxane, and

[0046] (vi) a combination of two or more thereof.

[0047] Polydiorganosiloxanes are known in the art and are commercially available. For example, DOWSIL TM 200 fluid, DOWSIL TM OS Fluids and XIAMETER TM PMX-200 silicone fluid is commercially available from The Dow Chemical Company, Midland, Michigan, USA.

[0048] Alternatively, (C) polyorganosiloxane may be a polysiloxane comprising unit formula (C-2): (R 4 2SiO2 / 2 ) y Cyclic polydiorganosiloxane, wherein R 4 As described above, and 15≥y≥3. Alternatively, the subscript y may be at least 3, alternatively at least 4, alternatively at least 5, and alternatively at least 6; at the same time, the subscript y may be at most 15, alternatively at most 12, alternatively at most 10, alternatively at most 8, and alternatively at most 6. Alternatively, the subscript y may have a value such that 12≥y≥3, alternatively 10≥y≥3, alternatively 8≥y≥3, alternatively 6≥y≥3, and alternatively 6≥y≥4.

[0049] Examples of cyclic polydiorganosiloxanes include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and combinations of two or more thereof. These cyclic polydiorganosiloxanes are commercially available from Sigma-Aldrich, Inc., St. Louis, Missouri, USA.

[0050] Starting material (C) is optional. However, when present, the amount of starting material (C) depends on various factors, including the type of polyorganohydrogensiloxane selected for starting material (B) and its Si-H content. The amount of (C) polyorganosiloxane may be from 0 wt % to <99 wt % based on the combined weight of starting materials (A), (B) and (C) in the composition.

[0051] Starting material (D) Solvent

[0052] Starting material (D) is an optional solvent, which can be used to promote the combination of starting material (A), (B) and / or (C) in the compositions and methods described herein. Solvents used herein are those that contribute to the fluidization of starting material but do not react substantially with any of these starting materials. Solvent can be selected based on the solubility of starting material and the volatility of solvent. Solubility refers to that the solvent is sufficient to dissolve and / or disperse the starting material. Volatility refers to the vapor pressure of the solvent. For example, starting material (A) phosphonium catalyst can be dissolved in a solvent before mixing starting material (A) with starting material (B) (and when there is (C)). Alternatively, starting material (B) can be dissolved in a solvent before mixing with starting material (A) (and when there is (C)), for example, when starting material (B) is a viscous fluid, such as gum, or solid at room temperature, such as resin. Alternatively, the starting material (C) may be dissolved in a solvent prior to mixing with the starting materials (A) and (B), for example, when the starting material (C) is a solid at room temperature, such as a resin or gum. The solvent may be used in any amount, which will be selected by one skilled in the art based on various factors, such as the choice of starting materials (A) and (B) (and (C) when present) and their solubility.

[0053] 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 chloroform, 1,1,1-trichloroethane or methylene chloride. One solvent or a combination comprising two or more solvents may be used herein.

[0054] The amount of solvent may depend on a variety of factors, including the type of solvent selected and the amount and type of other starting materials selected. However, the amount of solvent may be 0.1 wt % or more, alternatively 2 wt % or more, based on the combined weight of starting materials (A), (B) and (C), while the amount of solvent may be up to 99 wt %, alternatively up to 50 wt %. Alternatively, the amount of (D) solvent may be 0.1 wt % to 99 wt %, alternatively 2 wt % to 50 wt %, based on the combined weight of (A) catalyst, (B) polyorganohydrogensiloxane and (C) polyorganosiloxane compound in the composition.

[0055] The composition may be composed of (A) phosphonium catalyst and (B) polyorganohydrogensiloxane (and when present, (C) polyorganosiloxane and / or (D) solvent). Alternatively, the composition described herein may optionally further include additional components. Based on the weight of the composition, the optional additional components may be present in a concentration of 50 wt % or less, 40 wt % or less, 30 wt % or less, 20 wt % or less, 10 wt % or less, 5 wt % or less, or even 1 wt % or less. Alternatively, the optional additional components may be present in a concentration of 0 wt % to 50 wt %, alternatively 0 wt % to 40 wt %, alternatively 0 wt % to 30 wt %, alternatively 0 wt % to 20 wt %, alternatively 0 wt % to 10 wt %, alternatively 0 wt % to 5 wt %, and alternatively 1 wt % to 30 wt %.

[0056] Optional additional components

[0057] Examples of possible optional components include one or more than one component selected from the group consisting of: pigments, such as carbon black or titanium dioxide; fillers, such as metal oxides, including SiO2 (based on the weight of the composition, the concentration is generally 50% by weight or less); moisture scavengers; fluorescent whitening agents; stabilizers (such as antioxidants and UV stabilizers); and corrosion inhibitors. The composition may alternatively be free of any one or more than one such additional component. In addition, the composition may contain 1% by weight or less, alternatively 0.5% by weight or less of water, relative to the weight of the composition. Alternatively, the composition may be free of water.

[0058] The compositions described herein may be free of transition metals. "Free of transition metals" means that the composition does not contain metals from Groups 4-12 of the IUPAC Periodic Table of Elements as of December 1, 2018, or does not contain an undetectable amount, or an amount insufficient to cause the composition to form a gel after 24 hours at room temperature. Without being bound by theory, it is believed that transition metals can catalyze the reaction of Si-H and Si-O moieties at undesirably low temperatures (e.g., <65° C.).

[0059] The composition described herein may be free of Lewis bases. "Free of Lewis bases" means that the composition does not contain a compound or ionic species or contains an insufficient amount of a compound or ionic species that can donate electron pairs to the (A) phosphonium catalyst to prevent the composition from being sufficiently cured to form a gel within 20 minutes when heated at 65°C. For example, the composition may be free of a Lewis base selected from the group consisting of: PR 10 3. P(NR 10 2)3、NR 10 3. N(SiR 10 3) x R 103-x , R 10 C(NR 10 )N、P(NR 10 )R 10 3. Guanidine (C(=NR 10 )(NR 10 2)2)Amidine (R 10 C(=NR 10 )NR 10 2) Phosphazene and Where R 10 and R at each occurrence is independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, aryl, and substituted aryl.

[0060] method

[0061] The above composition can be a one-part composition. The one-part composition contains starting materials (A) and (B) in the same part. The composition can be prepared in a method comprising the following steps: i) mixing the above-mentioned starting materials comprising (A) phosphonium catalyst, (B) polyorganohydrogensiloxane and (C) polyorganosiloxane, (D) solvent and / or optional additional components when present, thereby forming a mixture. Starting material (D) solvent can be used to promote mixing starting materials (A) and (B) and when (C) is present. For example, one or more of starting materials (A) and (B) and when (C) is present can be dissolved in a solvent before mixing with other starting materials. Alternatively, the starting material can be substantially composed of the above-mentioned starting materials (A) and (B) (and optionally (C) and / or (D)). Alternatively, the starting material can be composed of the above-mentioned starting materials (A) and (B) (and optionally (C) and / or (D)).

[0062] Mixing the starting materials to form a mixture and prepare the polyorganohydrogensiloxane composition is carried out under conditions that will not cure (e.g., without causing Si-H moieties from (B) polyorganohydrogensiloxane to react significantly with Si-O-Si moieties (from (B) polyorganohydrogensiloxane and / or (C) polyorganosiloxane)). These conditions may include, for example, mixing by any convenient means. Mixing may be performed using conventional mixing equipment, such as a batch stirred tank. Alternatively, when the polyorganosiloxane compound selected for the starting material (C) and / or the polyorganohydrogensiloxane selected for the starting material (B) is viscous or solid (e.g., gum or resin), mixing under shear may be performed, for example, using an extruder. The composition may be formed, for example, by mixing the starting materials comprising (A) and (B) described above. The starting materials (A) and (B) may be mixed at room temperature or lower. Alternatively, the temperature for mixing the starting materials (A) and (B) (and (C) and / or (D), when present) may be 5°C to 30°C. The starting materials (A) and (B) (and (C) and / or (D), when present) may be mixed simultaneously. Alternatively, the starting materials (A) and (B) (and (D), when present) may be mixed to form a mixture, and thereafter, the mixture may be mixed with the starting material (C) (and further (D), when present), for example by adding the starting material (C) (or a solvent solution thereof) to the mixture, for example by metering over a period of time or by adding in one or more aliquots.

[0063] Curing composition

[0064] The method of curing the composition comprises:

[0065] 1) providing the composition as described above, and

[0066] 2) heating the composition to a temperature sufficient to catalyze the reaction of the silicon-bonded hydrogen atoms in (B) the polyorganohydrogensiloxane. For example, the temperature in step 2) may be ≥ 65°C. Alternatively, the temperature may 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 an additional step after step 1) and before step 2), wherein the additional step includes placing the composition in a mold or applying the composition to a substrate.

[0067] Example

[0068] 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 invention described in the claims. The starting materials used in these examples are shown in Table 1.

[0069] Table 1 - Starting Materials

[0070]

[0071]

[0072] Structure of Catalyst 1:

[0073]

[0074] Reference Example 1—General Conditions

[0075] Use in Reactions were performed in a N2-filled glove box with solvents dried over molecular sieves. Except as specified in Table 1, all starting materials were purchased from commercial sources and used as received.

[0076] A stock solution of Catalyst 1 was prepared as follows: [terpyPPh][B(C6F5)4] (56 mg) was dissolved in CH2Cl2 (1 mL) to give a 56 mg / mL solution.

[0077] A stock solution of FAB was prepared as follows: FAB (2.6 mg) was dissolved in CH2Cl2 (5.8 mL) to give FAB stock solution A (0.44 mg / mL).

[0078] Reference Example 2—Reaction Setup and Process

[0079] D H x (1 mL, 0.98 g) was added to a 30 mL vial containing a magnetic stirring bar. 1 mL of catalyst 1 stock solution (56 mg of [terpyPPh][B(C6F5)4]) was added to the vial. The resulting solution was stirred at 65°C by a preheated aluminum block. The reaction was monitored at different time intervals to observe whether a gel was formed. Gel formation indicated crosslinking (curing). The cured material was easily removed from the vial. The results are shown in Table 2 below.

[0080] Reference Example 3—Comparative Example Reaction Setup and Process

[0081] 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.

[0082] Table 2. Curing of D using FAB (comparative) and Catalyst 1 (invention) H x The catalyst was delivered in CH2Cl2.

[0083]

[0084] Industrial Applicability

[0085] The above-mentioned composition is shelf stable, which means that the composition does not gel at room temperature in 0.5 hours or less, alternatively in 1 hour or less, alternatively in 5 hours or less, alternatively in 24 hours or less, alternatively in 48 hours or less, and alternatively in 36 hours or less. The compositions and methods described herein can be used to prepare and cure silicone compositions, which are cured to form products such as coatings, adhesives, elastomers and foams. The inventors were surprised to find that the catalysts described herein will cure polyorganosiloxane compositions. In addition, the inventors were surprised to find that no Lewis base and / or bridging molecules are required to stabilize the catalysts described herein. Without wishing to be bound by theory, it is believed that the presence of a Lewis base such as triethylamine can make the composition of the present invention non-curable under the conditions tested in the above examples. The compositions and methods of the present invention provide polyorganohydrogensiloxane compositions that are shelf stable at room temperature and can be cured when heated to a mild temperature.

[0086] Definition and usage of terms

[0087] Abbreviations used in the specification have the definitions in Table 3 below.

[0088] Table 3 - Abbreviations

[0089]

[0090]

[0091] Unless otherwise indicated, all amounts, ratios and percentages are by weight. The amount of all starting materials in the composition is 100% by weight. The Summary of the Invention and the Abstract are hereby incorporated by reference. Unless otherwise indicated by the context of this specification, the articles "a", "an" and "the" each refer to one (a kind) or more (multiples). Unless otherwise indicated, the singular includes the plural meaning.

[0092] The term "comprising" and its derivatives, such as "having" and "containing", are used in the broadest sense herein, meaning and encompassing the concepts of "including", "consisting essentially of", and "consisting of". The use of "for example", "for example", "such as", and "including" to list illustrative examples is not meant to be limited to the listed examples. 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.

[0093] Generally, as used herein, a hyphen “-” or dash “–” within a range of values ​​means “to” or “up to”; ">” means “higher than” or “greater than”; “≥” means “at least” or “greater than or equal to”; “<” means “lower than” or “less than”; and “≤” means “at most” or “less than or equal to”.

[0094] Embodiments of the present invention

[0095] In a first embodiment, the composition comprises a mixture of:

[0096] 100 ppm to 100,000 ppm by weight, based on the combined weight of the starting materials (A) and (B), of (A) a phosphonium catalyst comprising:

[0097] (i) Formula [P(R 2 )(R 1 )] 2+ A tetravalent dication of phosphorus, wherein R 1 is an aryl group, and R 2 is a bipyridine ligand or a terpyridine ligand; and

[0098] (ii) Formula [BR 3 4] - A non-coordinating anion, where each R 3 are independently selected halogenated aryl groups;

[0099] 1 wt % to <100 wt % of (B) a polydiorganohydrogensiloxane selected from the group consisting of:

[0100] Including unit type (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, wherein each R 4 is an independently selected monovalent hydrocarbon group free of aliphatic unsaturation, and the values ​​of the subscripts g, h, i and j are such that g ≥ 0, h ≥ 0, the amount (g + h) = 2, i ≥ 0, j ≥ 0 and the amount (g + j) ≥ 1, and the amount (i + j) is 0 to 2,000;

[0101] Including unit formula (B-2): (R 42SiO 2 / 2 ) u (R 4 HSiO 2 / 2 ) v Cyclic polydiorganohydrogensiloxane, wherein R 4 As described above, subscript u is 0 or greater, subscript v is 1 or greater, and the amount (u+v) is 3 to 15; and

[0102] (B-3) A combination of (B-1) and (B-2).

[0103] In a second embodiment, in the composition according to the first embodiment, the (A) phosphonium catalyst comprises:

[0104] In a third embodiment, in the composition of the first or second embodiment, (B) polyorganohydrogensiloxane is selected from the group consisting of:

[0105] (i) α,ω-dimethylhydrogensiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane),

[0106] (ii) α,ω-dimethylhydrogensiloxy-terminated polymethylhydrogensiloxane,

[0107] (iii) α,ω-trimethylsilyloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane),

[0108] (iv) α,ω-trimethylsilyloxy-terminated polymethylhydrogensiloxane, and

[0109] (v) poly(dimethylsiloxane / methylhydrogensiloxane) terminated with α-dimethylhydrogensiloxy-ω-trimethylsiloxy,

[0110] (vi) polymethylhydrogensiloxane terminated with α-dimethylhydrogensiloxy-ω-trimethylsiloxy,

[0111] (vii) a combination of two or more thereof.

[0112] In a fourth embodiment, in the composition according to the first or second embodiment, (B) polyorganohydrogensiloxane is selected from the group consisting of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and a combination of two or more thereof.

[0113] In a fifth embodiment, in the composition of any one of the first to fourth 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.

[0114] In a sixth embodiment, in the composition of any one of the first to fifth embodiments, the composition further comprises 1 to 99 weight percent of (D) a solvent, based on the total weight of the composition.

[0115] In a seventh embodiment, the composition of any one of the first to sixth embodiments is used to prepare a product selected from the group consisting of coatings, adhesives, elastomers, and foams.

[0116] In an eighth embodiment, wherein the composition of any one of the first to sixth embodiments is a curing system, and the method comprises i) adding the composition to a polyorganosiloxane formulation and ii) curing the polyorganosiloxane formulation to form a product selected from the group consisting of a coating, an adhesive, an elastomer, and a foam.

Claims

1. A composition comprising a mixture of: (A) a phosphonium catalyst comprising (i) a tetravalent dication of phosphorus and (ii) a non-coordinating anion; and (B) a polyorganohydrogensiloxane.

2. The composition of claim 1, wherein (i) the tetravalent dication of phosphorus has the formula [P(R 2 )(R 1 )] 2+ , where each R 1 are 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.

3. The composition according to claim 2, wherein R 2 Selected from the group consisting of: The terpyridine ligand and the formula The bipyridine ligand, wherein each R is independently selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 6 carbon atoms.

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

5. The composition according to claim 4, wherein R 2 Selected from the group consisting of:

6. A composition according to any one of claims 1 to 5, wherein (ii) the non-coordinating anion has the formula [BR 3 4] - , where each R 3 Independently selected from the group consisting of a monovalent hydrocarbon group or a monovalent halogenated hydrocarbon group.

7. The composition of claim 6, wherein (ii) the non-coordinating anion has the formula [B(C6F5)4] - .

8. The composition of claim 7, wherein (A) the phosphonium catalyst has the formula:

9. The composition according to any one of claims 1 to 8, wherein (B) the polyorganohydrogensiloxane comprises two or more siloxane units selected from the group consisting of: 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 Unit; each R 4 are independently selected monovalent hydrocarbon groups free of aliphatic unsaturation.

10. The composition according to claim 9, wherein (B) the polyorganohydrogensiloxane is selected from the group consisting of: (B-1) including unit type (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 polyorganohydrogensiloxane, wherein R 4 as described above, and the values ​​of the subscripts g, h, i, and j are such that g ≥ 0, h ≥ 0, the amount (g + h) = 2, i ≥ 0, j ≥ 0, and the amount (g + j) ≥ 1, and the amount (i + j) is 0 to 1,000; (B-2) includes unit formula (R 4 2SiO 2 / 2 ) u (R 4 HSiO 2 / 2 ) v Cyclic polyorganohydrogensiloxane, wherein subscript u is 0 or greater, subscript v is 1 or greater, the amount (u+v) is 3 to 15, and each R is an independently selected monovalent hydrocarbon group; and (B-3) A combination of (B-1) and (B-2).

11. The composition according to any one of claims 1 to 10, further comprising (C) a polyorganosiloxane, wherein (C) the polyorganosiloxane comprises a 4 3SiO 1 / 2 , R 4 2SiO 2 / 2 , R 4 SiO 3 / 2 , and SiO 4 / 2 two or more siloxane units of units; wherein each R 4 are independently selected monovalent hydrocarbon groups free of aliphatic unsaturation.

12. The composition according to claim 11, wherein (C) the polyorganosiloxane is selected from the group consisting of: (C-1) includes unit formula (R 4 3SiO 1 / 2 )2(R 4 2SiO 2 / 2 ) x A linear polydiorganosiloxane, wherein R 4 As above, and 1,000 ≥ x ≥ 1; (C-2) includes unit formula (R 4 2SiO 2 / 2 ) y Cyclic polydiorganosiloxane, wherein R 4 As above, and 15 ≥ y ≥ 3; and (C-3) A combination of (C-1) and (C-2).

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

14. The composition of any one of claims 1 to 13, wherein the composition is free of transition metals.

15. A method comprising the steps of: 1) Providing a composition according to any one of claims 1 to 14, and 2) heating the composition to a temperature sufficient to catalyze the reaction of (B) the silicon-bonded hydrogen atoms in the polyorganohydrogensiloxane, and Optionally, the method further comprises an additional step after step 1) and before step 2), wherein the additional step comprises placing the composition in a mold or applying the composition on a substrate.

Images