Polyorganohydrosiloxane compositions comprising lewis acid mono-cationic phosphonium salts

Abstract

The present invention provides a composition comprising a phosphonium catalyst and a polyorganohydrogensiloxane. The composition is shelf-stable at room temperature and cures upon heating. The compositions and methods are useful for preparing polyorganosiloxane products, such as coatings, adhesives, elastomers, and foams.

Description

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

[0002] Provided are a curable polyorganosiloxane composition and a method for preparing and curing the same. More specifically, the curable polyorganosiloxane composition comprises a monocationic Lewis acid phosphonium salt (catalyst) and a polyorganohydrogensiloxane. Background Art

[0003] 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

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

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

[0006] Starting material (A) Phosphonium catalyst

[0007] The starting material (A) used herein is a phosphonium catalyst comprising (i) a tetravalent monocation of phosphorus and (ii) a non-coordinating anion. The tetravalent monocation of phosphorus is a Lewis acidic phosphonium cation of formula (i-1): [PR 1 3R 2 ] + , where each R 1 is an independently selected aryl halide, and each R 2 Independently selected from the group consisting of halogen atoms and electron withdrawing groups.

[0008] Halogenated aryl R 1 Can have the following 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] R 2 The halogen atom of R may be selected from the group consisting of bromine (Br), Cl and F; alternatively, Cl and F. Alternatively, R 2 The halogen atom may be F. 2 The electron withdrawing group may include an atom with an electronegativity ≥ 2.5 bonded to P, such as carbon (C) or oxygen (O). Alternatively, the electron withdrawing group may have the formula -CX'3, wherein X' is a halogen atom selected from Br, Cl or F; or is Cl or F; alternatively, F. Alternatively, R 2 The electron withdrawing group may have the formula -CF3. 2 The electron withdrawing group may have the formula -OR 9 , where R 9 is an alkyl group or an aryl group. 9 The alkyl group of may 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. Applicable to R 9 The aryl group may be monocyclic or polycyclic and may have a pendant hydrocarbon group. 9 The aryl groups of include phenyl, tolyl, xylyl and naphthyl, and also include aralkyl groups such as benzyl, 1-phenylethyl and 2-phenylethyl. 9 The aryl group may be monocyclic, such as phenyl, tolyl or benzyl; alternatively, R 9 The aryl group of may be phenyl.

[0010] Alternatively, in formula (i-1), each R 1 Alternatively, in formula (i-1), R2 Alternatively, (i) the tetravalent monocation of phosphorus may have the formula: [P(C6F5)3F] + .

[0011] In the (A) phosphonium catalyst, the (ii) anion is a non-coordinating anion. A 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 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 have been replaced by F, Cl or Br.

[0012] Applicable to R 3 The alkyl group of R may be linear, branched, cyclic, or a combination of two or more thereof. 3 Examples of the alkyl groups are 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 examples of the alkyl groups are 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.

[0013] Applicable to R 3 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. 3 The aryl group may be monocyclic, such as phenyl, tolyl or benzyl; alternatively, R 3The aryl group of R may be phenyl. 3 The halogenated aryl group may be as described above for R 1 The halogenated aryl group.

[0014] 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 It may be a halogenated aryl group. Alternatively, the anion may have the formula B(C6F5)4.

[0015] Alternatively, the (A) catalyst may have the formula:

[0016] The starting material (A) can be prepared by methods known in the art, for example, the method disclosed in Science, 2013, Vol. 341, pp. 1374-1377, by changing a suitable starting material. The starting material (A) used herein can be any one of the above catalysts, or a combination of two or more of the above catalysts.

[0017] The compositions described herein include a sufficient amount of (A) catalyst to cure the composition. The exact amount of (A) catalyst depends on various factors, including the choice of (B) polyorganohydrogensiloxane and whether (C) (non-functional) polyorganosiloxane is present. However, the composition may include sufficient catalyst to provide a tetravalent monocation of phosphorus at a concentration of at least 1 ppm, alternatively at least 2 ppm, alternatively at least 5 ppm; while, on the same basis, the amount may be up to 1,000 ppm, alternatively up to 500 ppm, alternatively up to 100 ppm, and alternatively up to 50 ppm; each based on the combined weight of the starting materials (A) and (B) (and (C) when present). Alternatively, the amount of (A) phosphonium catalyst may be 1 ppm to 1,000 ppm, alternatively 2 ppm to 500 ppm, alternatively 5 ppm to 100 ppm, and alternatively 10 ppm, based on the weight of (B) polyorganohydrogensiloxane and (when (C) (non-functional) polyorganosiloxane is present) (C) (non-functional) polyorganosiloxane in the composition.

[0018] Starting material (B) polyorganohydrogensiloxane

[0019] The composition described herein also comprises (B) a polyorganohydrogensiloxane. The polyorganohydrogensiloxane comprises both Si-H and Si-O-Si moieties. Therefore, the composition comprising (A) a phosphonium catalyst and (B) a polyorganohydrogensiloxane can be cured 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 (R4 2SiO 2 / 2 ) i (HR 4 SiO 2 / 2 ) j A linear polydiorganohydrogensiloxane, 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 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. The cyclic polydiorganohydrogensiloxane 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 TX 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 (which can be determined using quantitative infrared analysis according to ASTM E168), and the presence of any optional, additional starting materials. 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-trimethylsiloxyl-terminated polydimethylsiloxane,

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

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

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

[0045] (v) α,ω-trimethylsiloxyl-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 0 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 starting material (A), (B) and / or when there is (C), the combination of (C) in the compositions and methods described herein. Solvents used herein are those that contribute to the fluidization of the starting material but do not react with any of these starting materials substantially. Solvents can be selected based on the solubility of the starting material and the volatility of the 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 the starting material (A) is mixed with the starting material (B) (and when there is (C), (C)). Alternatively, starting material (B) can be dissolved in a solvent before mixing with the starting material (A) (and when there is (C), (C)), for example, when the starting material (B) is a viscous fluid, such as gum, or is 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 amount 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 (C) polyorganosiloxane and / or (D) solvent are present, (C) polyorganosiloxane and / or (D) solvent). Alternatively, the composition described herein may optionally further comprise 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 10 3-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 when there are (C) polyorganosiloxane, (D) solvent and / or optional additional components, (C) polyorganosiloxane, (D) solvent and / or optional additional components to form a mixture. Starting material (D) solvent can be used to promote mixing starting materials (A) and (B) and when there is (C), (C). For example, one or more of starting materials (A) and (B) and when there is (C), (C) 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 may consist 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 significantly react 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., a gum or resin), mixing under shear may be performed, for example, using an extruder. The composition may be formed, for example, by mixing the above-mentioned starting materials comprising (A) and (B). 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 (C) and / or (D) are present) may be from 5°C to 30°C. The starting materials (A) and (B) (and (C) and / or (D), when (C) and / or (D) are present) may be mixed simultaneously. Alternatively, the starting materials (A) and (B) (and (D), when (D) is present) may be mixed to form a mixture, and thereafter, the mixture may be mixed with the starting material (C) (and further (D), when further (D) is 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] Reference Example 1 - General Conditions

[0073] 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.

[0074] The catalyst stock solution was prepared as follows:

[0075] [(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).

[0076] [(C6F5)3PF][F] Stock Solution A': [P(C6F5)3F + ]F - (6.6 mg) was dissolved in CH2Cl2 (15 mL) to give [P(C6F5)3F + ]F - Stock solution A' (0.44 mg / mL).

[0077] [(C6F5)3PF][B(C6F5)4]+NEt3 stock solution A: Et3N and catalyst 1 were added in a 1:1 molar ratio. Et3N stock solution (49.9uL Et3N dissolved in 1mL CH2Cl2) was first added to the reaction mixture, followed by catalyst stock solution A (0.44mg / mL).

[0078] 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).

[0079] Reference Example 2 - Reaction Setup and Process of Working Example Using Catalyst 1 at Room Temperature .

[0080] D H x(1 mL, 0.98 g) was added to a 30 mL vial containing a magnetic stirring bar. To the vial was added 0.2 mL of [(C6F5)3PF][B(C6F5)4] stock solution A (0.088 mg of [(C6F5)3PF][B(C6F5)4]). The solution was stirred at room temperature. 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.

[0081] Reference Example 3 - Comparative Example Reaction Setup and Process

[0082] Reference Example 2 was repeated except that 0.2 mL of FAB stock solution A (0.088 mg FAB) was used. The results are shown in Table 2 below.

[0083] Reference Example 4-Comparative Example Reaction Setup and Process

[0084] 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 (1:1 molar ratio with catalyst 1) was used. The results are shown in Table 2 below.

[0085] Reference Example 5-Comparative Example Reaction Setup and Process

[0086] 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.

[0087] Reference Example 6 - Reaction Setup and Process of Working Example Using Catalyst 1 at 65°C

[0088] D H x (1 mL, 0.98 g) was added to a 30 mL vial containing a magnetic stirring bar. 0.5 mL of [(C6F5)3PF][B(C6F5)4] stock solution A (0.22 mg of [(C6F5)3PF][B(C6F5)4]) was added to the vial. The reaction was monitored at different time intervals to observe whether a gel was formed. The solution was kept at room temperature. The solution was then stirred at 65°C by a preheated aluminum block. Gel formation indicates crosslinking (curing). The cured material was easily removed from the vial. The results are shown in Table 2 below.

[0089] Reference Example 7-Comparative Example Reaction Setup and Process

[0090] 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 (1:1 molar ratio with catalyst 1) was used. The results are shown in Table 2 below.

[0091] Reference Example 8 - Comparative Example Reaction Setup and Process

[0092] 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.

[0093] Table 2 - Comparison of D of Catalyst 1 (Invention) and Catalyst 2 (Comparative Example) using FAB (Comparative Example) H x Curing .

[0094]

[0095] 1 No gelling after 24 hours at room temperature. Subsequently, the solution was allowed to stand over a 4-day holiday weekend when no one was present, and when observation was resumed, gel was observed to have formed.

[0096] The data in Table 2 of Reference Examples 2 and 6 show that phosphonium catalysts comprising a tetravalent monocation of phosphorus and a non-coordinating anion can be used to prepare one-part compositions that are stable (do not gel) for at least 1 day at room temperature but cure within 20 minutes at an elevated temperature of 65°C. Reference Examples 4 and 7 show that the presence of a Lewis base (triethylamine) prevents cure under the conditions tested. Reference Examples 5 and 8 show that Catalyst 2, which comprises a strongly coordinating anion, did not cure the composition when tested at 65°C. Reference Example 3 shows rapid cure at room temperature when FAB is used instead of the catalyst described herein.

[0097] Industrial Applicability

[0098] The above-mentioned compositions are shelf stable, which means that the compositions gel in 1 hour or less, alternatively 5 hours or less, alternatively 24 hours or less, alternatively 48 hours or less, and alternatively 36 hours or less at room temperature. 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. In contrast, the presence of Lewis bases such as triethylamine can make 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 shelf stable at room temperature and can be cured when heated to a mild temperature.

[0099] Definition and usage of terms

[0100] Abbreviations used in the specification have the definitions in Table 3 below.

[0101] Table 3 - Abbreviations

[0102] abbreviation definition ASTM ASTM International ℃ Celsius g gram GPC Gel Permeation Chromatography h Hour Me methyl mg mg min minute mL ml mmol mmol Ph Phenyl ppm Per million RT or rt Room temperature 23℃±2℃ s Second wt weight

[0103] 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 in the context of this specification, the articles "a", "a kind" and "the" each refer to one (a kind) or more (a variety). Unless otherwise indicated, the singular includes the plural meaning.

[0104] 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.

[0105] 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”.

[0106] Embodiments of the present invention

[0107] In a first embodiment, the composition comprises a mixture of:

[0108] 1 ppm to 1,000 ppm by weight, based on the combined weight of the starting materials (A) and (B), of a phosphonium catalyst comprising:

[0109] (i) Formula [PR 1 3R 2 ] + A tetravalent monocation of phosphorus, wherein each R 1 Yes

[0110] An independently selected halogenated aryl group, wherein each R 8 is selected from Cl, F or -CF3, and each R 2 independently selected from Br, Cl, F and -CF3, and

[0111] (ii) Type [BR 3 4] - A non-coordinating anion, where each R 3 independently selected from the group consisting of monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups;

[0112] 1 wt % to <100 wt % of (B) a polydiorganohydrogensiloxane selected from the group consisting of:

[0113] 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;

[0114] Including unit formula (B-2): (R 4 2SiO 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

[0115] (B-3) A combination of (B-1) and (B-2).

[0116] In a second embodiment, in the composition described in the first embodiment, (A) the phosphonium catalyst has the formula [(C6F5)3PF] + [B(C6F5)4] - .

[0117] In a third embodiment, in the composition of the first or second embodiment, (B) polyorganohydrogensiloxane is selected from the group consisting of:

[0118] (i) α,ω-dimethylhydrogensiloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane),

[0119] (ii) α,ω-dimethylhydrogensiloxy-terminated polymethylhydrogensiloxane,

[0120] (iii) α,ω-trimethylsilyloxy-terminated poly(dimethylsiloxane / methylhydrogensiloxane),

[0121] (iv) α,ω-trimethylsilyloxy-terminated polymethylhydrogensiloxane, and

[0122] (v) poly(dimethylsiloxane / methylhydrogensiloxane) terminated with α-dimethylhydrogensiloxy-ω-trimethylsiloxy,

[0123] (vi) polymethylhydrogensiloxane terminated with α-dimethylhydrogensiloxy-ω-trimethylsiloxy,

[0124] (vii) a combination of two or more thereof.

[0125] In a fourth embodiment, in the composition of any one of the first to third embodiments, (C) polyorganosiloxane is selected from the group consisting of α,ω-trimethylsiloxane-terminated polydimethylsiloxane, α,ω-dimethylphenylsiloxane-terminated poly(dimethylsiloxane / methylphenylsiloxane), α,ω-dimethylphenylsiloxane-terminated polymethylphenylsiloxane, α,ω-trimethylsiloxane-terminated poly(dimethylsiloxane / methylphenylsiloxane), α,ω-trimethylsiloxane-terminated polymethylphenylsiloxane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and a combination of two or more thereof.

[0126] In a fifth embodiment, in the composition of any one of the first to fourth embodiments, the composition further comprises 1 to 99 wt % of (D) a solvent, based on the total weight of the composition.

[0127] In a sixth embodiment, the composition of any one of the first to fifth embodiments is used to prepare a product selected from the group consisting of coatings, adhesives, elastomers, and foams.

[0128] In a seventh embodiment, wherein the composition of any one of the first to fifth 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 monocation of phosphorus and (ii) a non-coordinating anion; and (B) a polyorganohydrogensiloxane; wherein the composition does not contain a Lewis base.

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

3. The composition of claim 2, wherein (i) the tetravalent monocation of phosphorus has the formula 4. A composition according to any one of claims 1 to 3, wherein (ii) the non-coordinating anion has the formula [BR 3 4] - , where each R 3 are independently selected from the group consisting of monovalent hydrocarbon groups and monovalent halogenated hydrocarbon groups.

5. The composition of claim 7, wherein (ii) the anion has the formula B(C6F5)4 - .

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

7. 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 polydiorganohydrogensiloxane, 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 from 0 to 1,000; (B-2) includes unit formula (R 4 2SiO 2 / 2 ) u (R 4 HSiO 2 / 2 ) v a cyclic polydiorganohydrogensiloxane 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).

8. 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.

9. 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). 10 . The composition according to claim 1 , further comprising (D) a solvent.

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

12. 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 silicon-bonded hydrogen atoms in (B) the polyorganohydrogensiloxane; as well as Optionally, after step 1) and before step 2), the composition is placed in a mold or applied on a substrate.

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