Method for preparing a silicone-acrylate hybrid composition and hybrid composition formed thereby

Abstract

A method for preparing a silicone-acrylate hybrid composition is provided. The method includes irradiating an acrylate composition in the presence of: (i) a silicone article and / or (ii) a silicone composition; to polymerize the acrylate composition and obtain the silicone-acrylate hybrid composition. The acrylate composition includes an acrylate compound and an initiator.

Description

[0001] Cross - reference to related applications

[0002] This patent application claims the priority and all advantages of U.S. Provisional Patent Application No. 62 / 955,544, filed on December 31, 2019, the content of which is incorporated herein by reference. Technical field

[0003] The present disclosure generally relates to a method of preparing a silicone - acrylate hybrid composition and to a silicone - acrylate hybrid composition formed according to the method. Background art

[0004] Irradiation - curable silicone compositions are used in a variety of applications and numerous industries, such as conformal coatings and adhesives, due to their rapid ambient curing, flexibility, and stability. However, silicones generally have lower mechanical strength, toughness, and abrasion resistance than many other materials such as acrylic resins, urethanes, epoxies, and olefinic and aromatic polymers. Attempts to combine silicones with such other materials into hybrid - curable compositions to achieve their complementary benefits are often limited by polymer incompatibility, which results in poor mechanical properties and low light transmission. Summary of the invention

[0005] A method of preparing a silicone - acrylate hybrid composition is provided. A silicone - acrylate hybrid composition formed according to the method is also provided.

[0006] The method includes irradiating an acrylate composition in the presence of: (i) a silicone article and / or (ii) a silicone composition; to polymerize the acrylate composition and obtain the silicone - acrylate hybrid composition. The acrylate composition comprises an acrylate compound and an initiator. The acrylate compound has the general formula (A):

[0007]

[0008] In formula (A), each R is independently selected from H and a substituted or unsubstituted hydrocarbon - based group, R 1 is H or a substituted or unsubstituted hydrocarbon - based group having 1 to 10 carbon atoms, n is an integer equal to or greater than 1, and R 2 is selected from R 1 , an amine group, an alkyl group, an alkyl group substituted with a hydroxyl group or an amino group, or an n - valent moiety having a valence greater than 1 to 4. Detailed description

[0009] The method for preparing the silicone-acrylate hybrid composition may hereinafter be abbreviated as the "method". Similarly, the silicone-acrylate hybrid composition formed according to the method may hereinafter be abbreviated as the "hybrid composition". The term "hybrid composition" should not be construed or understood to mean that the hybrid composition is in a liquid or uncured form, as the hybrid composition may be a cured solid, as described hereinafter.

[0010] In a first general embodiment, the acrylate composition is irradiated in the presence of a silicone article. In this first general embodiment, the silicone article is typically formed prior to irradiating the acrylate composition. Thus, the silicone article may be referred to as "preformed". Alternatively, the silicone article may be partially cured in the method and further cured during and / or after irradiation of the acrylate composition. For example, the acrylate composition may be irradiated while heat is applied to the silicone article to effect further curing, i.e., the method may be a dual-curing method.

[0011] In these embodiments, the silicone article is substantially or fully cured prior to irradiating the acrylate composition. The silicone article may be formed by various curing mechanisms understood in the art and is not limited to a particular curing mechanism. Exemplary curing mechanisms for the silicone article are further described hereinafter and include, but are not limited to, addition-curable silicone compositions and condensation-curable silicone compositions. Similarly, as described hereinafter, the silicone article may be selected and characterized by the silicone composition used to prepare the silicone article. For example, the silicone article may be a rubber, elastomer, resin, etc.

[0012] In this first general embodiment, the acrylate composition is in-situ polymerized by irradiation in the presence of a photoinitiator and a silicone article to form a polymer (or "acrylate polymer"). The silicone article, acrylate composition, and photoinitiator are described in more detail hereinafter. The acrylate polymer together with the silicone article results in the hybrid composition.

[0013] In a second general embodiment, the acrylate composition is irradiated in the presence of a silicone composition. The silicone composition cures, polymerizes, and / or crosslinks to form a silicone article, and the acrylate composition polymerizes by irradiation and a photoinitiator to form a polymer. In certain embodiments further described hereinafter, irradiation also causes curing of the silicone composition.

[0014] The silicone article and / or polymer can be the same as or different from the silicone article and / or polymer between the first and second general embodiments. However, in the second general embodiment, the silicone article and the acrylate polymer are typically formed simultaneously and in the presence of each other. Thus, in the second general embodiment, the polymer formation can be referred to as simultaneous or "one-pot" polymerization. In certain embodiments, the curing of at least one of the compositions in the composition (i.e., the silicone or acrylate composition) can begin before the curing (or polymerization) of the other composition. Additionally, the silicone and acrylate compositions can be cured simultaneously by different methods, such as a combination of heating and irradiation.

[0015] In the third general embodiment, the acrylate composition is irradiated in the presence of the silicone article and the silicone composition. This third general embodiment encompasses aspects of the first and second general embodiments.

[0016] In certain embodiments, depending on the functional groups present in the silicone composition, i) the silicone article and / or the silicone composition and ii) the acrylate composition can react with each other at least in part. For example, the silicone article and the acrylate polymer can be chemically bonded to each other in the hybrid composition. In other embodiments, i) the silicone article and / or the silicone composition and ii) the acrylate composition do not react with each other (or are inert with respect to each other). Thus, in the hybrid composition, the silicone article and the acrylate polymer can be chemically bonded to each other and / or physically interpenetrated.

[0017] Irradiation of the acrylate composition polymerizes the acrylate composition, which in turn results in the hybrid composition. A "hybrid" generally means that the hybrid composition is formed from a combination of two (or more) different starting materials. In various embodiments, the hybrid composition comprises, consists essentially of, or consists of the silicone article and the acrylate polymer. In certain embodiments, the hybrid composition comprises, consists essentially of, or consists of the simultaneous reaction product of the silicone and acrylate compositions. The hybrid composition can be referred to as a silicone-organic elastomer.

[0018] In many embodiments, the hybrid composition can be classified as an interpenetrating polymer network (IPN) or a semi-interpenetrating network. For example, in various embodiments, the hybrid composition comprises the silicone article and the acrylate polymer. In these embodiments, the silicone article and the acrylate polymer are at least partially physically interpenetrated.

[0019] As understood in the art, an IPN is a polymer network that contains two or more networks, such as a first component network and a second component network, which are at least partially interpenetrated in polymer proportions but generally not covalently bonded to each other. Generally, the polymer networks cannot be separated unless chemical bonds are broken. It is conceivable that two or more component networks are entangled in such a way that the component networks are connected and cannot be pulled apart, but are not bonded to each other by any chemical bonds.

[0020] In contrast, a mixture of two or more preformed polymer networks is not an IPN. Specifically, simply mixing or otherwise combining two or more polymers does not produce an IPN. Further, if a silicone composition and an acrylate composition react with each other such that the silicone product and the acrylate polymer are chemically bonded to each other in the hybrid composition, the hybrid composition is not an IPN because the hybrid composition does not contain two distinct networks, but rather a hybrid network.

[0021] In certain embodiments, the hybrid composition can be classified as a semi-interpenetrating polymer network (SIPN). As understood in the art, an SIPN is a polymer that contains one or more networks and one or more linear or branched polymers, characterized by the penetration of at least some of the linear or branched macromolecules in the linear or branched macromolecules into at least one of the networks in molecular proportions. SIPNs are distinguished from IPNs because the constituent linear or branched polymers can in principle be separated from the constituent polymer networks without breaking chemical bonds.

[0022] Similar to IPNs, SIPNs can be classified as sequential SIPNs. These SIPNs are typically formed where a linear or branched component is formed after completion of the reaction leading to the formation of the network, and vice versa. Thus, to prepare IPNs and SIPNs, it should be understood that the different components can be formed simultaneously or sequentially.

[0023] As described above, silicone products can be formed by various curing mechanisms in the art. In various embodiments, the silicone composition is selected from the group consisting of: silicone compositions curable by hydrosilylation, silicone compositions curable by condensation, silicone compositions curable by free radicals, silicone compositions curable by irradiation (e.g., by free radicals, cations, or hydrosilylation), silicone compositions curable by ring-opening reaction, silicone compositions curable by thiol-ene, compositions curable by a hydrosilicon-silanol reaction, silicone compositions curable by epoxy, and combinations thereof. Silicone products can be formed from one or more of these compositions.

[0024] In a first general embodiment, the silicone article is typically formed prior to irradiation of the acrylate composition. In a specific embodiment, prior to irradiation of the acrylate composition, the silicone article is typically formed from a hydrosilylation-curable silicone composition or a condensation-curable silicone composition.

[0025] In a second general embodiment, the acrylate composition is typically irradiated in the presence of a silicone composition. In a specific embodiment, the acrylate composition is irradiated in the presence of a radiation-curable silicone composition. In this way, the two compositions polymerize in the presence of the other composition and can react at least partially with each other to form a hybrid composition.

[0026] In various embodiments, the silicone composition comprises or is a hydrosilylation-curable silicone composition. The silicone article can be formed from such a composition.

[0027] In certain embodiments, the hydrosilylation-curable silicone composition comprises (A) an organopolysiloxane having on average at least two silicon-bonded ethylenically unsaturated groups or silicon-bonded hydrogen atoms per molecule; (B) an organosilicon compound having on average at least two silicon-bonded hydrogen atoms or silicon-bonded ethylenically unsaturated groups per molecule, which is capable of reacting with the silicon-bonded ethylenically unsaturated groups or silicon-bonded hydrogen atoms in the organopolysiloxane (A); and (C) a hydrosilylation catalyst. When the organopolysiloxane (A) contains silicon-bonded ethylenically unsaturated groups, the organosilicon compound (B) contains at least two silicon-bonded hydrogen atoms per molecule, and when the organopolysiloxane (A) contains silicon-bonded hydrogen atoms, the organosilicon compound (B) contains at least two silicon-bonded ethylenically unsaturated groups per molecule. The organosilicon compound (B) may be referred to as a cross-linker / cross-linking agent. In certain embodiments, the organopolysiloxane (A) and / or the organosilicon compound (B) may independently contain more than two hydrosilylation-reactive functional groups (e.g., silicon-bonded ethylenically unsaturated groups and / or silicon-bonded hydrogen atoms per molecule), such as having on average 3, 4, 5, 6 or more hydrosilylation-reactive functional groups per molecule. In such embodiments, the hydrosilylation-curable silicone composition is formulated to be chain-extended and cross-linked by hydrosilylation (e.g., by having the number and / or type of hydrosilylation-reactive functional groups per molecule of the organopolysiloxane (A) different from the number and / or type of hydrosilylation-reactive functional groups per molecule of the organosilicon compound (B)). For example, in these embodiments, when the organopolysiloxane (A) contains at least two silicon-bonded ethylenically unsaturated groups per molecule, the organosilicon compound (B) may contain at least three silicon-bonded hydrogen atoms per molecule, and when the organopolysiloxane (A) contains at least two silicon-bonded hydrogen atoms per molecule, the organosilicon compound (B) may contain at least three silicon-bonded ethylenically unsaturated groups per molecule. Thus, the ratio of the hydrosilylation-reactive functional groups per molecule of the organopolysiloxane (A) to the hydrosilylation-reactive functional groups per molecule of the organosilicon compound (B) may be equal to, less than or greater than 1:1, such as 1:5 to 5:1, 1:4 to 4:1, 1:3 to 3:1, 1:2 to 2:1, 2:3 to 3:2 or 3:4 to 4:3.

[0028] The organopolysiloxane (A) and the organosilicon compound (B) may independently be linear, partially branched, branched, cyclic or resinous (network-like). Specifically, the organopolysiloxane (A) and the organosilicon compound (B) may comprise any combination of M, D, T and Q units. The symbols M, D, T and Q represent the functionality of the structural units of the organopolysiloxane. M represents a monofunctional unit R 0 3SiO 1 / 2 . D represents a difunctional unit R 02SiO 2 / 2 。T represents a trifunctional unit R 0 SiO 3 / 2 。Q represents a tetrafunctional unit SiO 4 / 2 。The general structural formulas of these units are shown below:

[0029]

[0030] In these structures / chemical formulas, each R 0 can be any hydrocarbon group, such as an aromatic, aliphatic, alkyl, alkenyl or alkynyl group or other moieties, such as a hydroxyl group, an alkoxy group or a hydrogen atom.

[0031] Specific organopolysiloxanes (A) and organosilicon compounds (B) can be selected based on the desired properties of the silicone product or hybrid composition. Selecting the components of the silicone composition allows a person skilled in the art to achieve a range of desired properties.

[0032] For example, in certain embodiments, one of the organopolysiloxane (A) and the organosilicon compound (B) includes a silicone resin, which generally includes T and / or Q units combined with M and / or D units. When the organopolysiloxane (A) and / or the organosilicon compound (B) includes a silicone resin, the organosilicon resin can be a DT resin, an MT resin, an MDT resin, a DTQ resin, an MTQ resin, an MDTQ resin, a DQ resin, an MQ resin, a DTQ resin, an MTQ resin or an MDQ resin. Generally, when a hydrosilylation-curable silicone composition contains a resin, the resulting silicone product or hybrid composition has increased rigidity.

[0033] In many embodiments, each of the organopolysiloxane (A) and the organosilicon compound (B) includes repeating D units, and the organopolysiloxane (A) and the organosilicon compound (B) can have independently selected degrees of polymerization. In these embodiments, both the organopolysiloxane (A) and the organosilicon compound (B) are organopolysiloxanes. Such organopolysiloxanes are substantially linear, but may contain some branching attributable to T and / or Q units. As an alternative, such organopolysiloxanes are straight-chain. In these embodiments, the resulting silicone product and / or hybrid composition is elastic.

[0034] The silicon-bonded ethylenically unsaturated group and the silicon-bonded hydrogen atom of the organopolysiloxane (A) and the organosilicon compound (B) can be independently side-chain, terminal, or in both positions.

[0035] In certain embodiments, the organopolysiloxane (A) has the general formula:

[0036] (R 3 R 4 2SiO1 / 2 ) w (R 4 2SiO 2 / 2 ) x (R 4 SiO 3 / 2 ) y (SiO 4 / 2 ) z (I)

[0037] wherein each R 3 is independently selected from hydrocarbyl groups which may be substituted or unsubstituted, and each R 4 is independently selected from R 3 and ethylenically unsaturated groups, provided that at least two of the R 4 are ethylenically unsaturated groups, and w, x, y and z are mole fractions such that w + x + y + z = 1. As understood in the art, for linear organopolysiloxanes, the subscripts y and z are typically 0, while for resins, the subscript y and / or z > 0. Various alternative embodiments are described below with reference to w, x, y and z. In these embodiments, the value of the subscript w can be from 0 to 0.9999, from 0 to 0.999, from 0 to 0.99, from 0 to 0.9, from 0.9 to 0.999, from 0.9 to 0.99, from 0.8 to 0.99 or from 0.6 to 0.99. The value of the subscript x is typically from 0 to 0.9, from 0 to 0.45 or from 0 to 0.25. The value of the subscript y is typically from 0 to 0.99, from 0.25 to 0.8 or from 0.5 to 0.8. The value of the subscript z is typically from 0 to 0.99, from 0 to 0.85, from 0.85 to 0.95, from 0.6 to 0.85, from 0.4 to 0.65, from 0.2 to 0.5, from 0.1 to 0.45, from 0 to 0.25 or from 0 to 0.15.

[0038] In certain embodiments, each R 3 is a C1 to C 10 hydrocarbyl group which may be substituted or unsubstituted and which may contain heteroatoms such as oxygen, nitrogen, sulfur, etc. within the hydrocarbyl group. Suitable for R 3The hydrocarbyl groups can independently be straight-chain, branched-chain, cyclic, or combinations thereof. Cyclic hydrocarbyl groups include aryl groups and saturated or non-conjugated cyclic groups. Cyclic hydrocarbyl groups can independently be monocyclic or polycyclic. Straight-chain and branched-chain hydrocarbyl groups can independently be saturated or unsaturated. An example of a combination of a straight-chain and a cyclic hydrocarbyl group is an aralkyl group. General examples of hydrocarbyl groups include alkyl groups, aryl groups, alkenyl groups, halo-carbon groups, etc., as well as their derivatives, modifications, and combinations. Examples of suitable alkyl groups include methyl, ethyl, propyl (e.g., isopropyl and / or n-propyl), butyl (e.g., isobutyl, n-butyl, tert-butyl, and / or sec-butyl), pentyl (e.g., isopentyl, neopentyl, and / or tert-pentyl), hexyl, hexadecyl, octadecyl, and branched-chain saturated hydrocarbon groups having 6 to 18 carbon atoms. Examples of suitable non-conjugated cyclic groups include cyclobutyl, cyclohexyl, and cycloheptyl groups. Examples of suitable aryl groups include phenyl, tolyl, xylyl, naphthyl, benzyl, and dimethylphenyl. Examples of suitable alkenyl groups include vinyl, allyl, propenyl, isopropenyl, butenyl, isobutenyl, pentenyl, heptenyl, hexenyl, hexadecenyl, octadecenyl, and cyclohexenyl groups. Examples of suitable monovalent halo-hydrocarbon groups (i.e., hydrocarbyl groups) include haloalkyl groups, aryl groups, and combinations thereof. Examples of haloalkyl groups include alkyl groups in which one or more of the above hydrogen atoms are replaced by halogen atoms such as F or Cl. Specific examples of haloalkyl groups include fluoromethyl, 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, 2,2-difluorocyclopropyl, 2,3-difluorocyclobutyl, 3,4-difluorocyclohexyl, and 3,4-difluoro-5-methylcycloheptyl, chloromethyl, chloropropyl, 2-dichlorocyclopropyl, and 2,3-dichlorocyclopentyl groups, as well as their derivatives. Examples of haloaryl groups include aryl groups in which one or more of the above hydrogen atoms are replaced by halogen atoms such as F or Cl. Specific examples of haloaryl groups include chlorobenzyl and fluorobenzyl groups.

[0039] by R 4The ethylenically unsaturated groups, which may be the same or different within the organopolysiloxane (A), are generally selected from alkenyl groups and alkynyl groups. "Alkenyl" means an acyclic, branched or unbranched monovalent hydrocarbon group having one or more carbon-carbon double bonds. Specific examples thereof include vinyl groups, allyl groups, hexenyl groups and octenyl groups. "Alkynyl" means an acyclic, branched or unbranched monovalent hydrocarbon group having one or more carbon-carbon triple bonds. Specific examples thereof include ethynyl, propynyl and butynyl groups. Various examples of ethylenically unsaturated groups include CH2=CH—, CH2=CHCH2—, CH2=CH(CH2)4—, CH2=CH(CH2)6—, CH2=C(CH3)CH2—, H2C=C(CH3)—, H2C=C(CH3)—, H2C=C(CH3)CH2—, H2C=CHCH2CH2—, H2C=CHCH2CH2CH2—, HC≡C—, HC≡CCH2—, HC≡CCH(CH3)—, HC≡CC(CH3)2— and HC≡CC(CH3)2CH2—. Generally, when R 4 is an ethylenically unsaturated group, the ethylenically unsaturated group is terminal in R 4 . As understood in the art, ethylenically unsaturated groups may be referred to as aliphatically unsaturated groups.

[0040] In these embodiments, the organosilicon compound (B) may be further defined as an organohydrosilane, an organopolysiloxane, an organohydrosiloxane or a combination thereof. The structure of the organosilicon compound (B) may be linear, partially branched, branched, cyclic or resinous (network-like). In non-cyclic polysilanes and polysiloxanes, the hydrogen atoms bonded to silicon may be located at the terminal, side-bonded or both terminal and side-bonded positions. Cyclosilanes and cyclosiloxanes generally have 3 to 12 silicon atoms, 3 to 10 silicon atoms or 3 to 4 silicon atoms. The organohydrosilane may be silane, disilane, trisilane or polysilane.

[0041] The hydrosilylation catalyst (C) includes at least one hydrosilylation catalyst that promotes the reaction between the organopolysiloxane (A) and the organosilicon compound (B). The hydrosilylation catalyst (C) is not limited and may be any known hydrosilylation reaction catalyst for catalyzing hydrosilylation reactions. Combinations of different hydrosilylation reaction catalysts may be used.

[0042] In some embodiments, the hydrosilylation catalyst (C) comprises transition metals of Groups VIII to XI. The transition metals of Groups VIII to XI refer to the modern IUPAC nomenclature. The Group VIII transition metals are iron (Fe), ruthenium (Ru), osmium (Os), and hassium (Hs); the Group IX transition metals are cobalt (Co), rhodium (Rh), and iridium (Ir); the Group X transition metals are nickel (Ni), palladium (Pd), and platinum (Pt); and the Group XI transition metals are copper (Cu), silver (Ag), and gold (Au). Their combinations, their complexes (such as organometallic complexes), and other forms of such metals can be used as the hydrosilylation catalyst (C).

[0043] Additional examples of catalysts suitable for the hydrosilylation catalyst (C) include rhenium (Re), molybdenum (Mo), Group IV transition metals (i.e., titanium (Ti), zirconium (Zr), and / or hafnium (Hf)), lanthanides, actinides, and Group I and Group II metal complexes (e.g., those including calcium (Ca), potassium (K), strontium (Sr), etc.). Their combinations, their complexes (such as organometallic complexes), and other forms of such metals can be used as the hydrosilylation catalyst (C).

[0044] The hydrosilylation catalyst (C) can be in any suitable form. For example, the hydrosilylation catalyst (C) can be a solid, examples of which include platinum-based catalysts, palladium-based catalysts, and similar noble metal-based catalysts, as well as nickel-based catalysts. Specific examples thereof include nickel, palladium, platinum, rhodium, cobalt, and similar elements, as well as platinum-palladium, nickel-copper-chromium, nickel-copper-zinc, nickel-tungsten, nickel-molybdenum, and similar catalysts including combinations of multiple metals. Additional examples of solid catalysts include Cu-Cr, Cu-Zn, Cu-Si, Cu-Fe-Al, Cu-Zn-Ti, and similar copper-containing catalysts, etc.

[0045] The hydrosilylation catalyst (C) can be in or on a solid support. Examples of supports include activated carbon, silica, silica-alumina, alumina, zeolites, and other inorganic powders / particles (such as sodium sulfate), etc. The hydrosilylation catalyst (C) can also be disposed in a medium, e.g., a solvent that dissolves the hydrosilylation catalyst (C), or alternatively a medium that only carries but does not dissolve the hydrosilylation catalyst (C). Such media are known in the art.

[0046] In a specific embodiment, the hydrosilylation catalyst (C) comprises platinum. In these embodiments, the hydrosilylation catalyst (C) is exemplified by, for example: platinum black, such as chloroplatinic acid, chloroplatinic acid hexahydrate, reaction products of chloroplatinic acid with monohydric alcohols, bis(ethylacetoacetato)platinum, bis(acetylacetonato)platinum, compounds of platinum chloride, and complexes of such compounds with olefins or organopolysiloxanes, and platinum compounds microencapsulated in a matrix or core-shell type compound. Microencapsulated hydrosilylation catalysts and methods for their preparation are also known in the art, as exemplified in U.S. Pat. Nos. 4,766,176 and 5,017,654, which are hereby incorporated by reference in their entirety.

[0047] A complex of platinum with an organopolysiloxane suitable for use as the hydrosilylation catalyst (C) comprises a complex of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane with platinum. These complexes can be microencapsulated in a resin matrix. Alternatively, the hydrosilylation catalyst (C) can comprise a complex of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane with platinum. The hydrosilylation catalyst (C) can be prepared by a method comprising reacting chloroplatinic acid with an aliphatically unsaturated organosilicon compound such as divinyltetramethyldisiloxane or an olefin-platinum-silyl complex. The olefin-platinum-silyl complex can be prepared, for example, by mixing 0.015 moles of (COD)PtCl2 with 0.045 moles of COD and 0.0612 moles of HMeSiCl2.

[0048] The hydrosilylation catalyst (C) can also or alternatively be a photoactivatable hydrosilylation reaction catalyst, which can be initiated to cure by irradiation and / or heating. The photoactivatable hydrosilylation reaction catalyst can be any hydrosilylation reaction catalyst that is particularly capable of catalyzing the hydrosilylation reaction upon exposure to radiation having a wavelength of 150 nanometers to 800 nanometers (nm). When the hydrosilylation catalyst (C) is photoactivatable, the silicone composition can be cured together with the acrylate composition by irradiation and / or heat. When the hydrosilylation catalyst (C) is photoactivatable, the silicone composition and the acrylate composition generally do not react with each other and cure separately in the presence of each other, thereby obtaining a hybrid composition.

[0049] Specific examples of photoactivatable hydrosilylation catalysts applicable to hydrosilylation catalyst (C) include, but are not limited to, β-diketonato platinum(II) complexes such as bis(2,4-pentanedionato)platinum(II), bis(2,4-hexanedionato)platinum(II), bis(2,4-heptanedionato)platinum(II), bis(1-phenyl-1,3-butanedionato)platinum(II), bis(1,3-diphenyl-1,3-propanedionato)platinum(II), bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)platinum(II); (η-cyclopentadienyl)trialkylplatinum complexes such as (Cp)trimethylplatinum, (Cp)ethyldimethylplatinum, (Cp)triethylplatinum, (chloro-Cp)trimethylplatinum, and (trimethylsilyl-Cp)trimethylplatinum, where Cp represents cyclopentadienyl; triazene oxide-transition metal complexes such as Pt[C6H5NNNOCH3]4, Pt[p-CN-C6H4NNNOC6H 11 4, Pt[p-H3COC6H4NNNOC6H 11 4, Pt[p-CH3(CH2) x -C6H4NNNOCH3]4, 1,5-cyclooctadiene.Pt[p-CN-C6H4NNNOC6H 11 2, 1,5-cyclooctadiene.Pt[p-CH3O-C6H4NNNOCH3]2, [(C6H5)3P]3Rh[p-CN-C6H4NNNOC6H 11 and Pd[p-CH3(CH2) x —C6H4NNNOCH3]2, where x is 1, 3, 5, 11, or 17; (η-diene)(σ-aryl)platinum complexes such as (η 4 -1,5-cyclooctadienyl)diphenylplatinum, η 4 -1,3,5,7-cyclooctatetraenyl)diphenylplatinum, (η 4 -2,5-norbornadienyl)diphenylplatinum, (η 4 -1,5-cyclooctadienyl)bis-(4-dimethylaminophenyl)platinum, (η 4 -1,5-cyclooctadienyl)bis-(4-acetylphenyl)platinum, and (η 4 -1,5-cyclooctadienyl)bis-(4-trifluoromethylphenyl)platinum. Generally, the photoactivatable hydrosilylation catalyst is a Pt(II) β-diketonato complex, and more typically, the catalyst is platinum(II) bis(2,4-pentanedionate).

[0050] The hydrosilylation catalyst (C) is present in the composition in a catalytic amount, i.e., an amount or quantity sufficient to promote its curing under the desired conditions. The hydrosilylation catalyst can be a single hydrosilylation catalyst or a mixture comprising two or more different hydrosilylation catalysts.

[0051] The concentration of the hydrosilylation catalyst (C) is sufficient to catalyze the addition reaction between the organopolysiloxane (A) and the organosilicon compound (B). In certain embodiments, the concentration of the hydrosilylation catalyst (C) is sufficient to provide from 0.1 ppm to 1000 ppm, from 0.5 ppm to 100 ppm, or from 1 ppm to 25 ppm of platinum group metals, based on the combined weight of the organopolysiloxane (A) and the organosilicon compound (B).

[0052] The hydrosilylation-curable silicone composition can be a two-part composition in which the organopolysiloxane (A) and the organosilicon compound (B) are in separate parts. In these embodiments, the hydrosilylation catalyst (C) can be present together with either or both of the organopolysiloxane (A) and the organosilicon compound (B). Alternatively, the hydrosilylation catalyst (C) can be separated from the organopolysiloxane (A) and the organosilicon compound (B) in a third part such that the hydrosilylation-reaction-curable organosilicon composition is a three-part composition.

[0053] In a specific embodiment, the hydrosilylation-curable silicone composition comprises an organopolysiloxane (A) having the following general formula:

[0054] wherein n is an integer such that the average molecular weight of component (A) is from 100 g / mol to 50,000 g / mol, from 1,000 g / mol to 25,000 g / mol, from 5,000 g / mol to 15,000 g / mol, from 7,500 g / mol to 12,500 g / mol, or from 9,000 g / mol to 11,000 g / mol.

[0055] In these or other specific embodiments, the hydrosilylation-curable silicone composition comprises an organosilicon compound (B) having the following general formula:

[0056] Where m is an integer such that the mol% of the hydride of component (B) is 5 to 50, 10 to 45, 15 to 40, 20 to 35, or 25 to 35; and where n is an integer such that the average molecular weight of component (B) is from 10 g / mol to 10,000 g / mol, 50 g / mol to 7,500 g / mol, 100 g / mol to 5,000 g / mol, 500 g / mol to 2,500 g / mol, 1,000 g / mol to 2,500 g / mol, or 1,500 g / mol to 2,000 g / mol.

[0057] In these or other specific embodiments, the hydrosilylation catalyst (C) comprises or is Karstedt's catalyst. Exemplary amounts of the hydrosilylation catalyst (C) are as described above.

[0058] The curing conditions for such hydrosilylation-curable silicone compositions can vary. For example, the hydrosilylation-curable silicone composition can be cured upon exposure to irradiation and / or heat. Those skilled in the art will understand how the choice of the hydrosilylation catalyst (C) affects the techniques for setting and curing. Specifically, when curing via irradiation is desired, a photoactivatable hydrosilylation catalyst is typically used.

[0059] The organopolysiloxane (A) and the organosilicon compound (B) typically react in a molar ratio of 1:1 to 1:3, 1:1 to 1:2, 1:1 to 1:1.5, 1:1 to 1:1.4, 1:1 to 1:1.3, 1:1 to 1:1.2, or 1:1 to 1:1.1. However, those skilled in the art will select the specific ratio utilized, for example in view of the specific components utilized, the desired properties of the silicone composition, etc.

[0060] The organopolysiloxane (A) and the organosilicon compound (B) can be mixed or otherwise combined using techniques understood in the art. In some embodiments, the reaction is carried out at elevated temperature. The elevated temperature can be selected and controlled according to the specific components utilized. Thus, those skilled in the art will readily select the elevated temperature in view of the reaction conditions and parameters selected and the description herein. The elevated temperature is typically greater than ambient temperature to 180 °C, such as 30 °C to 150 °C, 40 °C to 135 °C, 50 °C to 115 °C, 60 °C to 100 °C, or 70 °C to 85 °C.

[0061] In various embodiments, the silicone composition comprises or is a condensable-curable silicone composition. Silicone articles can be formed from such compositions.

[0062] In these embodiments, the condensable curable silicone composition comprises (A′) an organopolysiloxane having on average at least two silicon-bonded hydroxyl groups or hydrolysable groups per molecule; (B′) an organosilicon compound having on average at least two silicon-bonded hydrogen atoms, hydroxyl groups or hydrolysable groups per molecule; and (C′) a condensation reaction catalyst. Although any parameter or condition may be selectively controlled during the method or any of its individual steps, the relative humidity and / or moisture content of the ambient conditions may be selectively controlled to further influence the curing rate of the condensable curable silicone composition.

[0063] The organopolysiloxane (A') and the organosilicon compound (B') can independently be linear, partially branched, branched, cyclic or resinous (network-like). Specifically, the organopolysiloxane (A') and the organosilicon compound (B') can include any combination of M, D, T and Q units, as in the organopolysiloxane (A) and the organosilicon compound (B) disclosed above.

[0064] Particular organopolysiloxanes (A') and organosilicon compounds (B') can be selected based on the desired properties of the silicone article or hybrid composition. For example, in certain embodiments, one of the organopolysiloxane (A') and the organosilicon compound (B') includes a silicone resin, which typically includes T and / or Q units in combination with M and / or D units. When the organopolysiloxane (A’) and / or the organosilicon compound (B’) contains a silicone resin, the silicone resin can be a DT resin, an MT resin, an MDT resin, a DTQ resin, an MTQ resin, an MDTQ resin, a DQ resin, an MQ resin, a DTQ resin, an MTQ resin or an MDQ resin. Generally, when the condensable curable silicone composition contains a resin, the resulting silicone article or hybrid composition has increased rigidity.

[0065] As an alternative, in other embodiments, the organopolysiloxane (A') and / or the organosilicon compound (B') is an organopolysiloxane comprising repeating D units. Such organopolysiloxanes are substantially linear, but may include some branching attributable to T and / or Q units. As an alternative, such organopolysiloxanes are linear. In these embodiments, the resulting silicone article and / or hybrid composition is elastic.

[0066] The silicon-bonded hydroxyl groups and the silicon-bonded hydrogen atoms, hydroxyl groups or hydrolysable groups of the organopolysiloxane (A’) and the organosilicon compound (B') can be independently side-chain, terminal or in two positions.

[0067] As understood in the art, silicon-bonded hydroxyl groups are produced by hydrolysis of silicon-bonded hydrolysable groups. These silicon-bonded hydroxyl groups can condense with water to form siloxane bonds as a by-product.

[0068] Examples of hydrolyzable groups suitable for the organopolysiloxane (A') include the following silicon-bonded groups: H, a halide group, an alkoxy group, an alkylamino group, a carboxyl group, an alkyloxime group, an alkenyloxy group, or an N-alkylacylamino group. The alkylamino group may be a cyclic amino group.

[0069] In a specific embodiment, the organopolysiloxane (A') has the following general formula:

[0070] (R 3 R 5 2SiO 1 / 2 ) w’ (R 5 2SiO 2 / 2 ) x’ (R 5 SiO 3 / 2 ) y’ (SiO 4 / 2 ) z’ (II)

[0071] where each R 3 is as defined above, and each R 5 is independently selected from R 3 and a hydroxyl group, a hydrolyzable group, or a combination thereof, provided that at least two of the R 5 are a hydroxyl group, a hydrolyzable group, or a combination thereof, and w', x', y', and z' are mole fractions such that w' + x' + y' + z' = 1. As understood in the art, for linear organopolysiloxanes, the subscripts y' and z' are typically 0, while for resins, the subscript y' and / or z' > 0. Various alternative embodiments are described below with reference to w', x', y', and z'. In these embodiments, the value of the subscript w' can be from 0 to 0.9999, from 0 to 0.999, from 0 to 0.99, from 0 to 0.9, from 0.9 to 0.999, from 0.9 to 0.99, from 0.8 to 0.99, or from 0.6 to 0.99. The value of the subscript x' is typically from 0 to 0.9, from 0 to 0.45, or from 0 to 0.25. The value of the subscript y' is typically from 0 to 0.99, from 0.25 to 0.8, or from 0.5 to 0.8. The value of the subscript z' is typically from 0 to 0.99, from 0 to 0.85, from 0.85 to 0.95, from 0.6 to 0.85, from 0.4 to 0.65, from 0.2 to 0.5, from 0.1 to 0.45, from 0 to 0.25, or from 0 to 0.15.

[0072] As set forth above, the condensable curable silicone composition further comprises an organosilicon compound (B'). The organosilicon compound (B') can be linear, partially branched, branched, cyclic, or resinous (network). In certain embodiments, the organosilicon compound (B') has the formula R 3 qSiX 4-q , where R 3 is as defined above, X is a hydrolysable group, and q is 0 or 1.

[0073] Specific examples of the organosilicon compound (B') include alkoxysilanes such as CH3Si(OCH3)3, CH3Si(OCH2CH3)3, CH3Si(OCH2CH2CH3)3, CH3Si[O(CH2)3CH3]3, CH3CH2Si(OCH2CH3)3, C6H5Si(OCH3)3, C6H5CH2Si(OCH3)3, C6H5Si(OCH2CH3)3, CH2=CHSi(OCH3)3, CH2=CHCH2Si(OCH3)3, CF3CH2CH2Si(OCH3)3, CH3Si(OCH2CH2OCH3)3, CF3CH2CH2Si(OCH2CH2OCH3)3, CH2=CHSi(OCH2CH2OCH3)3, CH2=CHCH2Si(OCH2CH2OCH3)3, C6H5Si(OCH2CH2OCH3)3, Si(OCH3)4, Si(OC2H5)4 and Si(OC3H7)4; organoacetoxysilanes such as CH3Si(OCOCH3)3, CH3CH2Si(OCOCH3)3, and CH2=CHSi(OCOCH3)3; organoiminoxysilanes such as CH3Si[O-N=C(CH3)CH2CH3]3, Si[O-N=C(CH3)CH2CH3]4, and CH2=CHSi[O-N=C(CH3)CH2CH3]3; organoacetamidoxysilanes such as CH3Si[NHC(=O)CH3]3 and C6H5Si[NHC(=O)CH3]3; epoxy silanes such as 3-glycidoxypropyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; acrylate silanes and methacrylate silanes such as 3-methacryloxypropyltrimethoxysilane and 3-acryloxypropyltrimethoxysilane; aminosilanes such as CH3Si[NH(C4H9)]3 and CH3Si(NHC6H 11 )3; and organoaminoxysilanes.

[0074] The organosilicon compound (B') can be a single silane or a mixture of two or more different silanes (each as described above). Additionally, methods for preparing trifunctional and tetrafunctional silanes are well known in the art; many of these silanes are commercially available.

[0075] The concentration of the organosilicon compound (B') in the condensable curable silicone composition is sufficient to cure (crosslink) the organopolysiloxane (A'). The specific amount of the organosilicon compound (B') used depends on the desired degree of cure, which generally increases as the ratio of the number of moles of hydrolyzable groups bonded to silicon in the organosilicon compound (B') to the number of moles of hydroxyl groups bonded to silicon in the organopolysiloxane (A') increases. The optimal amount of the organosilicon compound (B') can be readily determined by routine experimentation.

[0076] The condensation catalyst (C') can be any condensation catalyst commonly used to promote the condensation of hydroxyl (silanol) groups bonded to silicon to form Si - O - Si bonds. Examples of condensation catalysts include, but are not limited to, complexes of amines, metals (such as lead, tin, zinc, iron, titanium, zirconium) with organic ligands (such as carboxyl, hydrocarbyl, alkoxy, etc.). In certain embodiments, the condensation catalyst (C') can be selected from tin(II) and tin(IV) compounds, such as tin(II) laurate, tin(II) octoate, dibutyltin dilaurate, dibutyltin diacetate, and tetrabutyltin; and titanium compounds, such as n - butyl titanate. In these or other embodiments, the condensation catalyst (C') can be selected from zinc - based, iron - based, and zirconium - based catalysts.

[0077] Based on the total weight of the organopolysiloxane (A') in the condensable curable silicone composition, the concentration of the condensation catalyst (C') is generally from 0.1% to 10% (w / w), from 0.5% to 5% (w / w), or from 1% to 3% (w / w).

[0078] When the condensable curable silicone composition contains a condensation catalyst (C'), the condensable curable silicone composition is generally a two - part composition, wherein the organopolysiloxane (A') and the condensation catalyst (C') are in separate parts. In this embodiment, the organosilicon compound (B') is generally present together with the condensation catalyst (C'). As an alternative, the condensable curable organosilicon composition can be a three - part composition, wherein the organopolysiloxane (A'), the organosilicon compound (B'), and the condensation catalyst (C') are in separate parts.

[0079] The curing conditions for such condensable curable silicone compositions can vary. For example, the condensable curable silicone composition can cure when exposed to ambient conditions, a humid atmosphere, and / or heat.

[0080] In various embodiments, the silicone composition comprises or is a radiation - curable silicone composition, which can also be referred to as a free - radical - curable silicone composition. Silicone articles can be formed from such compositions.

[0081] In certain embodiments among those embodiments encompassed by the second general embodiment, the acrylate composition is irradiated in the presence of the silicone composition. In these embodiments, irradiating the acrylate composition also cures the silicone composition simultaneously.

[0082] In certain embodiments, the radiation-curable silicone composition comprises (A”) an organopolysiloxane having on average at least two silicon-bonded radiation-curable groups and (C”) a free-radical initiator. In other embodiments, the radiation-curable silicone composition comprises (A”) an organopolysiloxane having at least one silicon-bonded radiation-curable group; (B”) a crosslinking agent; and (C”) a free-radical initiator.

[0083] The organopolysiloxane (A”) can be linear, partially branched, branched, cyclic, or resinous (network-like). Specifically, the organopolysiloxane (A”) can include any combination of M, D, T, and Q units, such as the organopolysiloxane (A) and the organosilicon compound (B) disclosed above.

[0084] The specific organopolysiloxane (A”) can be selected based on the desired properties of the silicone article or hybrid composition. For example, it may be desirable for the silicone article to be in the form of an elastomer, gel, resin, etc., and selecting the components of the silicone composition allows those skilled in the art to achieve a range of desired properties.

[0085] In certain embodiments, the organopolysiloxane (A”) includes a silicone resin, which generally includes T and / or Q units in combination with M and / or D units. When the organopolysiloxane (A”) includes a silicone resin, the silicone resin can be a DT resin, MT resin, MDT resin, DTQ resin, MTQ resin, MDTQ resin, DQ resin, MQ resin, DTQ resin, MTQ resin, or MDQ resin. Generally, when the radiation-curable silicone composition contains a resin, the resulting silicone article or hybrid composition has increased rigidity.

[0086] Alternatively, in other embodiments, the organopolysiloxane (A”) includes repeating D units. Such organopolysiloxanes are substantially linear, but may include some branching attributable to T and / or Q units. As an alternative, such organopolysiloxanes are linear. In these embodiments, the silicone article or resulting hybrid composition is elastic.

[0087] The silicon-bonded, irradiatively curable groups of the organopolysiloxane (A'') can be side-chain, terminal or in two positions. The silicon-bonded, irradiatively curable groups can comprise, for example, ethylenically unsaturated groups in the form of double bonds and / or triple bonds. Exemplary examples of silicon-bonded, irradiatively curable groups include silicon-bonded alkenyl groups and silicon-bonded alkynyl groups. The irradiatively curable groups can be bonded to silicon directly or indirectly via a bridging group such as an alkylene, ether, ester, amide or another group.

[0088] In a specific embodiment, the organopolysiloxane (A'') has the following general formula:

[0089] (R 3 R 6 2SiO 1 / 2 ) w” (R 6 2SiO 2 / 2 ) x” (R 6 SiO 3 / 2 ) y” (SiO 4 / 2 ) z” (III)

[0090] where each R 3 is as defined above, and each R 6 is independently selected from R 3 and an irradiatively curable group, provided that at least two of the R 6 are irradiatively curable groups, and w'', x'', y'' and z'' are mole fractions such that w'' + x'' + y'' + z'' = 1. As is understood in the art, for linear organopolysiloxanes, the subscripts y'' and z'' are typically 0, while for resins, the subscript y'' and / or z'' > 0. The various alternative embodiments are described below with reference to w'', x'', y'' and z''. In these embodiments, the value of the subscript w'' can be from 0 to 0.9999, from 0 to 0.999, from 0 to 0.99, from 0 to 0.9, from 0.9 to 0.999, from 0.9 to 0.99, from 0.8 to 0.99 or from 0.6 to 0.99. The value of the subscript x'' is typically from 0 to 0.9, from 0 to 0.45 or from 0 to 0.25. The value of the subscript y'' is typically from 0 to 0.99, from 0.25 to 0.8 or from 0.5 to 0.8. The value of the subscript z'' is typically from 0 to 0.99, from 0 to 0.85, from 0.85 to 0.95, from 0.6 to 0.85, from 0.4 to 0.65, from 0.2 to 0.5, from 0.1 to 0.45, from 0 to 0.25 or from 0 to 0.15.

[0091] From R 6The irradiatable curable groups represented may be the same as or different from each other. In various embodiments, the silicon-bonded irradiatable curable groups of component (A") are independently selected from acryloyloxyalkyl groups, substituted acryloyloxyalkyl groups, vinyl ether groups, alkenyl groups, acrylate functional groups, epoxy functional groups, alkynyl groups, thiol-substituted organic groups, hydrosilyl groups, and epoxy-substituted organic groups. Combinations of such groups may also be used. Generally, the acryloyloxyalkyl group may include an alkyl acrylate group, such as methacrylate.

[0092] The irradiatable curable silicone composition may further comprise an unsaturated compound selected from the following: (i) at least one organosilicon compound having at least one silicon-bonded ethylenically unsaturated group per molecule; (ii) at least one organic compound having at least one aliphatic carbon-carbon double bond per molecule; (iii) at least one organosilicon compound having at least one silicon-bonded acryloyl group per molecule; (iv) at least one organic compound having at least one acryloyl group per molecule; or (v) a mixture comprising (i), (ii), (iii), and (iv). The unsaturated compound may have a straight-chain, branched-chain, or cyclic structure. The unsaturated compound may comprise an irradiatable curable group other than the ethylenically unsaturated group, such as any of those groups described above.

[0093] The organosilicon compound may be an organosilane or an organosiloxane. The organosilane may be silane, disilane, trisilane, or polysilane. Similarly, the organosiloxane may be disiloxane, trisiloxane, or polysiloxane. The cyclic silane and cyclic siloxane generally have 3 to 12 silicon atoms, 3 to 10 silicon atoms, or 3 to 4 silicon atoms. In non-cyclic polysilanes and polysiloxanes, the silicon-bonded ethylenically unsaturated group may be located at the terminal, side group, or both the terminal and side group positions.

[0094] Specific examples of organosilanes include, but are not limited to, silanes having the following formula:

[0095] Vi4Si, PhSiVi3, MeSiVi3, PhMeSiVi2, Ph2SiVi2, and PhSi(CH2CH=CH2)3,

[0096] where Me is methyl, Ph is phenyl, and Vi is vinyl.

[0097] Specific examples of organosiloxanes include, but are not limited to, siloxanes having the following formula:

[0098] PhSi(OSiMe2Vi)3, Si(OSiMe2Vi)4, MeSi(OSiMe2Vi)3, and Ph2Si(OSiMe2Vi)2,

[0099] Wherein Me is methyl, Vi is vinyl and Ph is phenyl.

[0100] The organic compound can be any organic compound containing at least one aliphatic carbon-carbon double bond per molecule, provided that the compound does not prevent the curing of the organopolysiloxane (A"). The organic compound can be an alkene, diene, triene or polyene. Additionally, in acyclic organic compounds, one or more carbon-carbon double bonds can be in terminal positions, side-chain positions or both terminal and side-chain positions.

[0101] The organic compound can contain one or more functional groups that are not aliphatic carbon-carbon double bonds. Examples of suitable functional groups include but are not limited to -O-, >C=O, -CHO, -CO2-, -C≡N, -NO2, >C=C<, -C≡-, -F, -Cl, -Br and -I. The suitability of a particular unsaturated organic compound for the radiation-curable silicone composition can be readily determined by routine experimentation.

[0102] Examples of organic compounds containing aliphatic carbon-carbon double bonds include but are not limited to 1,4-divinylbenzene, 1,3-hexadienylbenzene, and 1,2-divinylcyclobutane.

[0103] The unsaturated compound can be a single unsaturated compound or a mixture containing two or more different unsaturated compounds (each as described above). For example, the unsaturated compound can be a single organosilane, a mixture of two different organosilanes, a single organopolysiloxane, a mixture of two different organopolysiloxanes, a mixture of an organosilane and an organopolysiloxane, a single organic compound, a mixture of two different organic compounds, a mixture of an organosilane and an organic compound, or a mixture of an organopolysiloxane and an organic compound.

[0104] As described above, in other embodiments, the radiation-curable silicone composition comprises an organopolysiloxane (A") having at least one, optionally at least two, silicon-bonded radiation-curable groups (A"); a crosslinker (B"); and a free radical initiator (C"). The crosslinker (B") can be the same as or different from the unsaturated compound described above. In various embodiments, the crosslinker (B") comprises an acrylate having at least two functional groups that are reactive with the silicon-bonded radiation-curable groups of the organopolysiloxane (A"). Examples of the crosslinker (B") include polyfunctional acrylates. Specific examples of suitable polyfunctional acrylates are described below for embodiments of the acrylate composition.

[0105] In a specific embodiment, the radiation-curable silicone composition comprises an organopolysiloxane (A") having the following general formula:

[0106] where n is an integer such that the average molecular weight of component (A'') is from 100 g / mol to 50,000 g / mol, from 1,000 g / mol to 25,000 g / mol, from 5,000 g / mol to 15,000 g / mol, from 7,500 g / mol to 12,500 g / mol, or from 9,000 g / mol to 11,000 g / mol.

[0107] The free radical initiator (C'') is a radical-generating compound and is used to initiate the polymerization of the organopolysiloxane (A''). Generally, the free radical initiator (C'') generates radicals via dissociation caused by irradiation, heat, and / or reduction by a reducing agent.

[0108] In each embodiment, the free radical initiator (C'') is selected from any known free radical type photoinitiator that effectively promotes the crosslinking reaction. Examples of suitable photoinitiators include benzophenone, acetonaphthone, acetophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, 2,2-diethoxyacetophenone, 3-hydroxypropyl phenyl ketone, 3-hydroxypropyl-p-isopropylphenyl ketone, diethoxyxanthone, chloro-thioxanthone, azobisisobutyronitrile, N-methyldiethanolamine benzophenone, 4,4'-bis(dimethylamino)benzophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and combinations thereof.

[0109] In each embodiment, the free radical initiator (C'') is an azo compound or an organic peroxide compound. Suitable azo compounds include azobenzene, azobenzene-p-sulfonic acid, azobis-dimethylvaleronitrile, azobisisobutyronitrile, and combinations thereof. Suitable organic peroxide compounds include dialkyl peroxides, diaryl peroxides, diacyl peroxides, alkyl hydroperoxides, and aryl hydroperoxides. Alternatively, the organic peroxide can be, for example, benzoyl peroxide; dibenzoyl peroxide; 4-chlorobenzoyl peroxide; dicumyl peroxide; tert-butyl peroxybenzoate; tert-butyl peroxycumene; tert-butyl peroxide 2,5-dimethyl-2,5-di-tert-butylperoxyhexane; 2,4-dichlorobenzoyl peroxide; di-tert-butylperoxy-diisopropylbenzene; 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane; 2,5-di-tert-butylperoxyhexane-3,2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; cumyl-tert-butyl peroxide; or a combination of two or more of them.

[0110] The free radical initiator (C”) can be a single compound or a mixture comprising two or more different initiators. Based on the weight of the organopolysiloxane (A”), the concentration of the free radical initiator (C”) is typically from 0.1% to 5% (w / w) or from 0.2% to 2% (w / w). The radiation curable silicone composition can be a two-part composition, wherein the organopolysiloxane (A”) and the free radical initiator (C”) are in separate parts.

[0111] In various embodiments, the silicone composition comprises or is curable by ring-opening reaction. Silicone articles can be formed from such compositions.

[0112] In certain embodiments, the ring-opening reaction curable silicone composition comprises (A''') an organopolysiloxane having on average at least two epoxy group-substituted groups per molecule and (C''') a curing agent. However, the ring-opening reaction curable silicone composition is not specifically limited to epoxy-functional organopolysiloxanes. Other examples of ring-opening reaction curable organosilicon compositions include those containing silacyclobutane and / or benzocyclobutene.

[0113] The organopolysiloxane (A''') can be linear, partially branched, branched, cyclic or resinous (network). Specifically, the organopolysiloxane (A''') can include any combination of M, D, T and Q units, such as the organopolysiloxane (A) and the organosilicon compound (B) disclosed above.

[0114] A particular organopolysiloxane (A''') can be selected based on the desired properties of the silicone article or hybrid composition. For example, it may be desired for the silicone article to be in the form of an elastomer, gel, resin, etc., and selection of the components of the silicone composition allows one skilled in the art to achieve a range of desired properties.

[0115] In certain embodiments, the organopolysiloxane (A''') comprises a silicone resin, which typically comprises T and / or Q units in combination with M and / or D units. When the organopolysiloxane (A''') comprises a silicone resin, the silicone resin can be a DT resin, MT resin, MDT resin, DTQ resin, MTQ resin, MDTQ resin, DQ resin, MQ resin, DTQ resin, MTQ resin or MDQ resin. Generally, when a hydrosilylation curable silicone composition contains a resin, the resulting silicone article or hybrid composition has increased rigidity.

[0116] Alternatively, in other embodiments, the organopolysiloxane (A''') comprises repeating D units. Such organopolysiloxanes are substantially linear, but may include some branching attributable to T and / or Q units. As an alternative, such organopolysiloxanes are linear. In these embodiments, the resulting silicone article or hybrid composition is elastic.

[0117] The epoxy-substituted group of the organopolysiloxane (A''') can be side-chain, terminal or at two positions. An "epoxy-substituted group" is generally a monovalent organic group in which an oxygen atom of the epoxy substituent is directly attached to two adjacent carbon atoms of a carbon chain or ring system. Examples of epoxy-substituted organic groups include, but are not limited to, 2,3-epoxypropyl, 3,4-epoxybutyl, 4,5-epoxypentyl, 2-glycidyloxyethyl, 3-glycidyloxypropyl, 4-glycidyloxybutyl, 2-(3,4-epoxycyclohexyl)ethyl, 3-(3,4-epoxycyclohexyl)propyl, 2-(3,4-epoxy-3-methylcyclohexyl)-2-methylethyl, 2-(2,3-epoxycyclopentyl)ethyl and 3-(2,3-epoxycyclopentyl)propyl.

[0118] In a specific embodiment, the organopolysiloxane (A''') has the following general formula:

[0119] (R 3 R 7 2SiO 1 / 2 ) w”’ (R 7 2SiO 2 / 2 ) x”’ (R 7 SiO 3 / 2 ) y”’ (SiO 4 / 2 ) z”’ (IV)

[0120] where each R 3 is as defined above, and each R 7 is independently selected from R 3 and epoxy-substituted groups, provided that R 7At least two of them are epoxy group-substituted groups, and w”', x”, y”', and z”' are mole fractions such that w”'+x”'+y”'+z”' = 1. As understood in the art, for linear organopolysiloxanes, the subscripts y”' and z”' are usually 0, while for resins, the subscript y”' and / or z”' > 0. Various alternative embodiments are described below with reference to w”', x”', y”', and z”'. In these embodiments, the value of the subscript w”' can be from 0 to 0.9999, from 0 to 0.999, from 0 to 0.99, from 0 to 0.9, from 0.9 to 0.999, from 0.9 to 0.99, from 0.8 to 0.99, or from 0.6 to 0.99. The value of the subscript x”' is usually from 0 to 0.9, from 0 to 0.45, or from 0 to 0.25. The value of the subscript y”' is usually from 0 to 0.99, from 0.25 to 0.8, or from 0.5 to 0.8. The value of the subscript z”' is usually from 0 to 0.99, from 0 to 0.85, from 0.85 to 0.95, from 0.6 to 0.85, from 0.4 to 0.65, from 0.2 to 0.5, from 0.1 to 0.45, from 0 to 0.25, or from 0 to 0.15.

[0121] The curing agent (C”') can be any curing agent suitable for curing the organopolysiloxane (A”'). Examples of curing agents (C”') suitable for this purpose include phenolic compounds, carboxylic acid compounds, acid anhydrides, amine compounds, compounds containing alkoxy groups, compounds containing hydroxyl groups, or mixtures thereof or their partial reaction products. More specifically, examples of the curing agent (C”') include tertiary amine compounds such as imidazole; quaternary amine compounds; phosphorus compounds such as phosphonic acid; aluminum compounds such as organoaluminum compounds; and zirconium compounds such as organozirconium compounds. In addition, a curing agent or a curing catalyst or a combination of a curing agent and a curing catalyst can be used as the curing agent (C”'). The curing agent (C”') can also be a photoacid or a photoacid generating compound.

[0122] The ratio of the curing agent (C”') to the organopolysiloxane (A”') is not limited. In certain embodiments, this ratio is from 0.1 to 500 parts by weight of the curing agent (C”') per 100 parts by weight of the organopolysiloxane (A”').

[0123] In various embodiments, the silicone composition comprises or is a thiol-ene curable silicone composition. Silicone articles can be formed from such compositions.

[0124] In certain embodiments, the thiol-ene curable silicone composition comprises: (A””) an organopolysiloxane having on average at least two silicon-bonded ethylenically unsaturated groups or silicon-bonded mercaptoalkyl groups per molecule; (B””) an organosilicon compound having on average at least two silicon-bonded mercaptoalkyl groups or silicon-bonded ethylenically unsaturated groups per molecule, capable of reacting with the silicon-bonded ethylenically unsaturated groups or silicon-bonded mercaptoalkyl groups in the organopolysiloxane (A””); (C””) a catalyst; and (D””) an optional organic compound containing two or more mercapto groups. When the organopolysiloxane (A””) contains silicon-bonded ethylenically unsaturated groups, the organosilicon compound (B””) and / or the organic compound (D””) contains at least two mercapto groups bonded to silicon and / or in the organic compound per molecule, and when the organopolysiloxane (A””) contains silicon-bonded mercapto groups, the organosilicon compound (B””) contains at least two silicon-bonded ethylenically unsaturated groups per molecule. The organosilicon compound (B””) and / or the organic compound (D””) may be referred to as a crosslinking agent or crosslinking reagent.

[0125] The catalyst (C””) can be any catalyst suitable for catalyzing the reaction between the organopolysiloxane (A””) and the organosilicon compound (B””) and / or the organic compound (D””). Generally, the catalyst (C””) is selected from: i) free radical catalysts; ii) nucleophiles; and (iii): combinations of (i) and (ii). Suitable free radical catalysts for use as the catalyst (C””) include photoactivated free radical catalysts, thermally activated free radical catalysts, room temperature free radical catalysts (such as redox catalysts and alkylborane catalysts), and combinations thereof. Suitable nucleophiles for use as the catalyst (C””) include amines, phosphines, and combinations thereof.

[0126] In various embodiments, the silicone composition comprises or is a silicone composition curable by a hydrosilicon-silanol reaction. Silicone articles can be formed from such compositions.

[0127] In certain embodiments, a silicone composition curable by a silane-silanol reaction comprises: (A''') an organopolysiloxane having on average at least two silicon-bonded hydrogen atoms or at least two siloxane-bonded hydroxyl groups per molecule; (B''') an organosilicon compound having on average at least two silicon-bonded hydroxyl groups or at least two silicon-bonded hydrogen atoms per molecule, which is capable of reacting with the silicon-bonded hydrogen atoms or silicon-bonded hydroxyl groups in the organopolysiloxane (A'''); (C''') a catalyst; and (D''') an optional active hydrogen-containing compound. When the organopolysiloxane (A''') contains silicon-bonded hydrogen atoms, each molecule of the organosilicon compound (B''') and / or the organic compound (D''') contains at least two hydroxyl groups bonded to silicon and / or in the active hydrogen-containing compound, and when the organopolysiloxane (A''') contains silicon-bonded hydroxyl groups, each molecule of the organosilicon compound (B''') contains at least two silicon-bonded hydrogen atoms. The organosilicon compound (B''') and / or the organic compound (D''') may be referred to as a crosslinking agent or crosslinking reagent.

[0128] Typically, the catalyst (C''') is selected from: i) a Group X metal-containing catalyst such as platinum; ii) a base such as a metal hydroxide, an amine or a phosphine; and (iii) combinations thereof.

[0129] As described above, the acrylate composition comprises an acrylate compound having the general formula (A):

[0130]

[0131] In formula (A), each R is independently selected from H and a substituted or unsubstituted hydrocarbon group, R 1 is H or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, n is an integer equal to or greater than 1, and R 2 is selected from R 1 , an amine group, an alkyl group, an alkyl group substituted with a hydroxyl group or an amino group, or an n-valent moiety having a valence greater than 1 to 4.

[0132] In certain embodiments, each R is an independently selected substituted or unsubstituted hydrocarbon group having 1 to 10, 1 to 8, 1 to 6, 1 to 4, 1 or 2, or 1 carbon atom. In other embodiments, at least one R is a substituted or unsubstituted hydrocarbon group and the other R is H. In still other embodiments, each R is H.

[0133] In certain embodiments, R 1 is H. In other embodiments, R 1 is a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms. The R of the acrylate compound1 Examples of suitable substituted or unsubstituted hydrocarbon groups are the same as those described above for R in the silicone composition 3 described above. In various embodiments, R 1 is an alkyl group, such as methyl.

[0134] R 2 can be the same as or different from R 1 . Suitable alkyl groups for R 2 include those described above for R 3 . The alkyl groups of R 2 can optionally be substituted with, for example, a hydroxyl group or an amino group. In certain embodiments, R 2 is an alkoxy group, such as methoxy, ethoxy, propoxy or butoxy. In other embodiments, R 2 is an amine group. Still further, R 2 can be a moiety with a valence greater than 1, such as a silicon atom. When R 2 is a moiety with a valence greater than 1, the acrylate compound is a polyfunctional acrylate, such as a difunctional acrylate, trifunctional acrylate or tetrafunctional acrylate.

[0135] In various embodiments, the subscript n is 1. In other embodiments, n is greater than 1. In certain embodiments, n is from 1 to 4, from 1 to 2 or is 1. The moiety with a valence n greater than 1 can include one or more atoms, such as carbon atoms, and can be a prepolymer or oligomer.

[0136] Thus, the acrylate compound can be monofunctional or polyfunctional. Examples of suitable polyfunctional acrylates are commercially available from Sartomer, Arkema and Miwon. In certain embodiments, the acrylate composition comprises at least one monofunctional acrylate, at least one polyfunctional acrylate (i.e., having two or more functional groups) or a combination thereof.

[0137] In various embodiments, the acrylate compound of the acrylate composition is selected from the group consisting of acrylates, acrylamides, amino-substituted acrylates, hydroxy-substituted acrylates and combinations thereof. In certain embodiments, the acrylate composition further comprises acrylic acid. In other embodiments, the acrylate composition is substantially to completely free of acrylic acid.

[0138] Specific examples of compounds suitable as acrylate compounds typically include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, and tert-butyl (meth)acrylate, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, and tert-butyl acrylate. In certain embodiments, the acrylate compound is selected from methyl (meth)acrylate, ethyl (meth)acrylate, and n-butyl (meth)acrylate. In some embodiments, the acrylate compound is selected from methyl acrylate, ethyl acrylate, and n-butyl acrylate. In a specific embodiment, the acrylate compound is methyl (meth)acrylate (MMA).

[0139] Additional specific examples of compounds suitable as acrylate compounds typically include hydroxyethyl acrylamide, N-isopropylacrylamide, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, methacrylamide, N,N'-dimethylaminoacrylamide, tert-butyl acrylamide, tert-octyl acrylamide, dimethylaminopropyl methacrylamide, dimethylaminoethyl methacrylamide, dimethylaminopropyl acrylamide, dimethylaminoethyl acrylamide, N,N-bis-(dimethylaminoethyl)methacrylamide, N,N-bis-(dimethylaminopropyl)acrylamide, N,N-bis-(dimethylaminoethyl)acrylamide, and N,N-bis-(dimethylaminopropyl)methacrylamide; amino-substituted acrylates and methacrylates such as dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, dimethylaminoethyl acrylate, and dimethylaminopropyl acrylate; hydroxyalkyl acrylates and hydroxyalkyl methacrylates such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxypropyl acrylate. Combinations of two or more compounds can also be used as acrylate compounds.

[0140] The acrylate compound can be used in any form, such as in pure form (i.e., lacking solvents, carrier media, diluents, etc.) or disposed in a carrier medium (such as a solvent or dispersant). The carrier medium (if present) can comprise or be an organic solvent (e.g., aromatic hydrocarbons such as benzene, toluene, xylene, etc.; aliphatic hydrocarbons such as heptane, hexane, octane, etc.; halogenated hydrocarbons such as dichloromethane, 1,1,1-trichloroethane, chloroform; etc.; ethers such as diethyl ether, tetrahydrofuran, etc., alcohols such as methanol, ethanol, etc.), silicone fluid, an aqueous solvent (e.g., water), or a combination thereof.

[0141] In certain embodiments, the acrylate composition is free or substantially free of a carrier vehicle. In some such embodiments, the acrylate composition is free or substantially free of water and carrier vehicle / volatiles that react with other components present. For example, in certain embodiments, the method can include stripping the acrylate composition of volatiles and / or solvents (such as water, organic solvents such as alcohols, ethers, etc.). Techniques for stripping acrylate compositions are understood in the art and can include distillation, heating, drying, applying reduced pressure / vacuum, azeotroping with solvents, applying molecular sieves, etc. and combinations thereof.

[0142] An initiator is a compound that generates free radicals and is used to initiate the polymerization of the acrylate composition. In certain embodiments, an initiator is also utilized to initiate the polymerization of the silicone composition. Generally, the initiator generates free radicals through dissociation caused by irradiation, heat, and / or reduction caused by a reducing agent.

[0143] In various embodiments, the initiator is selected from any known free radical type photoinitiator that effectively promotes crosslinking reactions. Examples of suitable photoinitiators include benzophenone, acetonaphthone, acetophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, 2,2 - diethoxyacetophenone, 3 - hydroxypropyl phenyl ketone, 3 - hydroxypropyl - p - isopropylphenyl ketone, diethoxythioxanthone, chloro - thioxanthone, azo - bis - isobutyronitrile, N - methyldiethanolamine benzophenone, 4,4'-bis(dimethylamino)benzophenone, 2,2 - dimethoxy - 1,2 - diphenylethane - 1 - one, 2 - methyl - 1 - [4 - (methylthio)phenyl]-2 - morpholinopropan - 1 - one, 1 - [4 - (2 - hydroxyethoxy)phenyl]-2 - hydroxy - 2 - methyl - propan - 1 - one, 2 - benzyl - 2 - dimethylamino - 1 - (4 - morpholinophenyl)butan - 1 - one, bis(2,4,6 - trimethylbenzoyl)phenylphosphine oxide, and combinations thereof.

[0144] In various embodiments, the initiator includes an azo compound or an organic peroxide compound. Suitable azo compounds include azobenzene, azobenzene-p-sulfonic acid, azobis(dimethylvaleronitrile), azobisisobutyronitrile, and combinations thereof. Suitable organic peroxide compounds include dialkyl peroxides, diaryl peroxides, diacyl peroxides, alkyl hydroperoxides, and aryl hydroperoxides. Alternatively, the organic peroxide can be, for example, benzoyl peroxide; dibenzoyl peroxide; 4-chlorobenzoyl peroxide; dicumyl peroxide; tert-butyl peroxybenzoate; tert-butyl cumyl peroxide; tert-butyl peroxide 2,5-dimethyl-2,5-di-tert-butylperoxyhexane; 2,4-dichlorobenzoyl peroxide; di-tert-butylperoxy-diisopropylbenzene; 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane; 2,5-di-tert-butylperoxyhexane-3,2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; cumyl-tert-butyl peroxide; or a combination of two or more of them.

[0145] The initiator can be a single compound or a mixture comprising two or more different initiators. Based on the weight of the acrylate composition, the concentration of the initiator is typically from 0.1% to 5% (w / w) or from 0.2% to 2% (w / w).

[0146] In various embodiments, at least one of the silicone article, the silicone composition, or the acrylate composition comprises and / or is formed in the presence of at least one additive. The additive can be selected from conventional additives known in the art. Examples of suitable additives include, but are not limited to, reaction (or polymerization) inhibitors, solvents, fillers, stabilizers, and the like.

[0147] In certain embodiments, the acrylate composition is irradiated in the presence of a polymerization inhibitor. The polymerization inhibitor is not limited and can include, or can be, a radical scavenger, an antioxidant, a light stabilizer, a UV absorber, etc., or a combination thereof. Such compounds are known in the art and generally are or contain chemical compounds or groups capable of interacting with free radicals to render the free radicals ineffective (e.g., by forming covalent bonds between them to eliminate the free radicals). The polymerization inhibitor can also include or be a polymerization retarder, i.e., a compound that reduces the initiation and / or growth rate of free radical polymerization. For example, in some embodiments, the polymerization inhibitor includes or is oxygen. Generally, the polymerization inhibitor is used to prevent and / or inhibit the formation of by-products that can be formed by the free radical polymerization of certain acrylate compounds and / or acryloyloxy-functional organosilicon compounds.

[0148] The polymerization inhibitor is not limited and may include phenolic compounds, quinones or hydroquinone compounds, N-oxy compounds, phenothiazine compounds, hindered amine compounds, or combinations thereof, alternatively may be phenolic compounds, quinones or hydroquinone compounds, N-oxy compounds, phenothiazine compounds, hindered amine compounds, or combinations thereof. Other compounds suitable for or useful as polymerization inhibitors include phenothiazine (PTZ) and compounds having a similar structure, such as phenoxazine, promazine, N,N'-dimethylphenazine, carbazole, N-ethylcarbazole, N-benzylphenothiazine, N-(1-phenylethyl)phenothiazine, N-alkylated phenothiazine derivatives such as N-benzylphenothiazine and N-(1-phenylethyl)phenothiazine, etc. Other suitable polymerization inhibitors include, for example, acetylenic alcohols, such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, or 2-phenyl-3-butyn-2-ol; enyne compounds, such as 3-methyl-3-penten-1-yne or 3,5-dimethyl-3-hexen-1-yne; or 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, or benzotriazole. Of course, the polymerization inhibitor may include any number of specific compounds, which may be selected independently of each other and the same as or different from any other compounds of the polymerization inhibitor.

[0149] If used, the polymerization inhibitor may be added to the reaction as a discrete component or may be combined with another component (e.g., the acrylate composition before irradiation). The polymerization inhibitor can be used in any amount, which will be selected by those skilled in the art, for example, depending on the specific inhibitor selected, the reaction parameters employed, the reaction scale (e.g., the total amount of the acrylate composition), the reaction atmosphere, the reaction temperature, and / or pressure, etc. In certain embodiments, based on the total amount of the acrylate composition, the polymerization inhibitor is present in an amount of 50 ppm to 2,000 ppm.

[0150] Exemplary embodiments are described below. Additional embodiments can be understood with reference to the following examples.

[0151] In an example of the first general embodiment, a silicone article that can be preformed (e.g., commercially available) or prepared is provided. In certain embodiments, the method includes preparing a silicone article. For example, the silicone article can be prepared from one or more of the silicone compositions described above. Conventional forming methods are understood by those of ordinary skill in the art.

[0152] An acrylate composition and an initiator are provided. These components can be provided together or separately from each other. In various embodiments, these components are first combined to form a solution. The solution can be homogeneous or heterogeneous.

[0153] The silicone article and the solution (and / or its individual components) can be combined in any order, and the silicone article is infused and swollen by the acrylate composition to form a swollen silicone material. The acrylate composition is generally dispersed throughout the silicone article.

[0154] The silicone article and the acrylate composition can be combined in various amounts. In various embodiments, the silicone article and the acrylate composition are combined in a mass ratio of 1:10 to 10:1, 1:9 to 9:1, 1:8 to 8:1, 1:7 to 7:1, 1:6 to 6:1, 1:5 to 5:1, 1:4 to 4:1, 1:3 to 3:1, 1:2 to 2:1, or 1:1.

[0155] The silicone material can be swollen at room temperature (e.g., 23 ± 2 °C) or elevated temperature. The swelling can occur over a period of time until a stable equilibrium is reached. The period of time can vary and can be in the range of 1 minute to 120 minutes, 30 minutes to 90 minutes, 45 minutes to 75 minutes, or 55 minutes to 65 minutes.

[0156] The swollen silicone material can be used to form and / or subsequently placed in a confined and optionally inert environment (e.g., in a container or reactor purged with nitrogen). If high temperature is used, the container or reactor can be heated in any suitable manner, such as by a jacket, heating mantle, heating plate, coil, etc.

[0157] Additional acrylate composition can be introduced, for example, by an air stream or a liquid stream. Such introduction can be used to avoid or prevent evaporation effects. In certain embodiments, the container or reactor can be pressurized to facilitate the swelling of the silicone article and / or reduce or prevent the evaporation of certain components.

[0158] Then the swollen silicone material is irradiated. For example, the swollen silicone material is exposed to UV irradiation to polymerize the acrylate composition and form an acrylate polymer in situ. The excess acrylate composition can be removed from the swollen silicone article in advance, for example, to prevent the formation of a skin during curing. The irradiation and polymerization of the acrylate composition in the swollen silicone material form a silicone-acrylate hybrid composition.

[0159] The irradiation can be carried out by methods understood in the art. In various embodiments, the acrylate composition is irradiated (and thus cured) by ultraviolet (UV) light irradiation. For example, low-pressure, high-pressure, or ultra-high-pressure mercury lamps, metal halide lamps, (pulsed) xenon lamps, or electrodeless lamps can be used as UV lamps. The irradiation dose can vary. In certain embodiments, the irradiation dose is in the range of 5 mJ / cm 2 to about 6,000 mJ / cm 2 or in the range of about 10 mJ / cm 2 to about 4,000 mJ / cm2 within the range of.

[0160] In some embodiments, at least one of the components comprises a carrier vehicle or solvent. In other embodiments, the irradiation is carried out in the absence of any carrier vehicle or solvent. For example, no carrier vehicle or solvent may be discretely combined with a silicone article, an acrylate composition, etc. In these or other embodiments, none of the components are disposed in any carrier vehicle or solvent such that no carrier vehicle or solvent is present during the polymerization of the acrylate composition.

[0161] Optionally, the hybrid composition may be exposed to a vacuum, a purge gas, or a combination of both to remove volatiles. For example, in embodiments where the acrylate composition comprises MMA, a vacuum may be applied to remove residual materials.

[0162] In an example of the second general embodiment, the silicone composition, the acrylate composition, and the initiator are combined in a single liquid solution. The components may be combined using conventional techniques and held, for example, in a container or reactor.

[0163] In many embodiments, the silicone composition comprises or is a silicone composition curable by irradiation. In these embodiments, the silicone composition curable by irradiation comprises an organopolysiloxane (A"), which has at least one, optionally at least two, silicon-bonded groups curable by irradiation; optionally a crosslinking agent (B"); and a free radical initiator (C"). In a specific embodiment, the silicone composition curable by irradiation comprises an organopolysiloxane (A"), which has at least two silicon-bonded groups curable by irradiation; and a free radical initiator (C"). Examples of such components are disclosed above, which describe the silicone composition. In other embodiments, the silicone composition comprises or is a silicone composition curable by hydrosilylation.

[0164] The silicone composition and the acrylate composition can be combined in various amounts. In various embodiments, the silicone and acrylate compositions are combined in a volume ratio of 1:10 to 10:1, 1:9 to 9:1, 1:8 to 8:1, 1:7 to 7:1, 1:6 to 6:1, 1:5 to 5:1, 1:4 to 4:1, 1:3 to 3:1, 1:2 to 2:1, or 1:1. In additional embodiments, the organopolysiloxane (A”) and the acrylate composition are combined in a volume ratio of 1:10 to 10:1, 1:9 to 9:1, 1:8 to 8:1, 1:7 to 7:1, 1:6 to 6:1, 1:5 to 5:1, 1:4 to 4:1, 1:3 to 3:1, 1:2 to 2:1, or 1:1. The ratio of the silicone composition and the acrylate composition is selected based on those compositions utilized and the desired properties of the hybrid composition and its end-use applications. In certain embodiments, it may be desirable to have an excess of silicone articles in the hybrid composition, while in other embodiments, it may be desirable to have an excess of acrylate polymer in the hybrid composition.

[0165] The solution is then irradiated to simultaneously polymerize the silicone and acrylate compositions. Other curing methods, such as applying heat, can be used in combination with irradiation, particularly if the silicone composition is thermally curable, for example if the silicone composition comprises a silicone composition curable by hydrosilylation. This forms a silicone-acrylate hybrid composition. The irradiation can be carried out as described above. Optionally, the hybrid composition can be exposed to a vacuum after formation to remove volatiles.

[0166] A composite article is also provided. The composite article includes a silicone-acrylate hybrid composition. In various embodiments, the composite article includes the hybrid composition disposed on a substrate. In certain embodiments, the hybrid composition is sandwiched between at least two substrates, which can be the same or different from each other. The hybrid composition can be formed directly on the substrate or formed separately from the substrate and subsequently applied to the substrate. The present disclosure is not limited to a particular material type or substrate geometry. In a specific embodiment, at least one substrate is conventional for an electronic device or its components.

[0167] In various embodiments, the substrate includes an electronic device. The present disclosure is not limited to a particular electronic device. Specific examples of electronic devices are circuit boards. The circuit board or electronic device is not limited and can be used, for example, in the automotive industry, control modules, consumer applications and appliances, computers, mobile phones, etc.

[0168] In certain embodiments, the hybrid composition is used as a conformal coating. Without being bound or limited by any particular theory, it is believed that the hybrid composition provides excellent properties relative to conventional conformal coatings. For example, the silicone aspect of the hybrid composition provides excellent optical clarity (which can be easily inspected), and the acrylate aspect of the hybrid composition provides excellent mechanical properties such as rigidity, toughness, etc.

[0169] As understood in the art, conformal coatings can be used to conform to the profile of a printed circuit board to protect the components of the board. Such coatings can be applied in various thicknesses, such as an average thickness of 25 μm to 250 μm (micrometers). Conformal coatings applied to electronic circuit systems generally help prevent moisture, dust, chemicals, and extreme temperatures.

[0170] In these embodiments, the hybrid composition can be applied in a variety of ways, including brush coating, spray coating, dispensing, dip coating, etc. In certain embodiments, the hybrid composition includes at least one colorant (such as a fluorescent dye) to assist in inspection of the coating coverage.

[0171] In other embodiments, the hybrid composition is used as an adhesive composition or in an adhesive composition. The adhesive composition can be used in many applications, and the present disclosure is not limited to a particular application. For example, the adhesive composition can be used in optically clear resins, which are commonly used in displays, camera modules, image sensor bonding, small / micro LEDs, smart watches, etc.

[0172] The following examples illustrating embodiments of the present disclosure are intended to illustrate and not limit the invention. The working examples generally fall within the first general embodiment and the second general embodiment of the inventive method as described above. Certain components used in the examples are listed in Table 1 below.

[0173] Table 1 – Components

[0174]

[0175] First general method

[0176] Organopolysiloxane 1 is combined with an organosilicon compound to form a mixture. An increased temperature and a hydrosilylation catalyst are used to cure the mixture to form an initial silicone network, which can also be referred to as a silicone article.

[0177] Next, a solution of MMA and 1 weight percent (wt%) of a photoinitiator is provided. The silicone article and the solution are combined, and the silicone article is infused and swollen through the solution to form a swollen silicone material.

[0178] The swollen silicone material is then placed in a confined and inert environment and exposed to UV irradiation to in-situ polymerize PMMA (from MMA). This forms a silicone-acrylate hybrid composition.

[0179] Depending on, for example, the amounts of silicone and PMMA formed or present, the mass of the hybrid composition can range from pure PDMS (e.g., elastomeric, rubbery, etc.) to higher PMMA contents (e.g., higher modulus and toughness, e.g., tougher). Additionally, optical transparency can be maintained to a reasonable extent, for example, with a light blue color hue, up to a PMMA mass fraction of nearly 50%. Optical transparency can be measured according to ASTM D1003-13.

[0180] Comparative Example 1: Preparation of silicone products

[0181] The silicone formulation is initially prepared in a two-part (Part A and Part B) mixture for subsequent combination in a 1:1 mass ratio. Part A consists of 8.66 grams (g) of organopolysiloxane 1, 1.34 g of organosilicon compound, and 0.01 g of reaction inhibitor. Part B consists of 10.00 g of organopolysiloxane 1 and 0.178 g of diluted catalyst. The diluted catalyst is a hydrosilylation catalyst, which is further diluted to a 5 wt.% p-xylene solution to obtain a Pt content of 1,000 ppm.

[0182] After adding each new component, each part is mixed in a Flaktek speed mixer at 2,500 revolutions per minute (rpm) for 1 minute. Then, 3.00 g of each part is added to a third speed mixer cup and immediately mixed together at 2,500 rpm for 1 minute. Then, 5 g of this combined mixture is transferred to a 10 centimeter (cm) diameter round polystyrene petri dish and spread evenly, and then placed in an oven set at 75 °C for 2 hours.

[0183] The sample is then removed from the oven, and the crosslinked PDMS is removed from the petri dish using tweezers. Next, the resulting round PDMS sheet is cut into 20 millimeter by 20 millimeter (mm) square samples, or in some cases, 45 mm by 45 mm square samples, using a scalpel.

[0184] Practical Examples 1 to Practical Example 4

[0185] The above samples were used to form different hybrid compositions in Examples 1 to 4 below. In these examples, different amounts of PMMA were formed in situ to prepare interpenetrating polymer networks (IPNs) of different PMMA and silicone articles. Specifically, samples of the silicone articles formed in Comparative Example 1 were separately immersed in solutions of different volume / volume of MMA and solvent having 1 wt% photoinitiator. Each of the immersed samples in the immersed samples was swollen at room temperature (RT) until a stable equilibrium was reached (at least 1 hour).

[0186] Table 2 - In-situ IPN formation

[0187]

[0188] After reaching a stable equilibrium, each of the immersed samples in the immersed samples was removed from the solution with tweezers, excess solution was removed from the sample surface with a Kim wipe, and the sample was placed between two glass slides and clamped together. This was done quickly and efficiently to minimize evaporation losses of MMA in the sample.

[0189] Then the "sandwiched" samples were placed in a closed chamber with a quartz glass top. Nitrogen was bubbled through the MMA and then flowed through the chamber for 5 minutes before UV irradiation exposure. A 375 nanometer (nm) UV irradiation lamp (LEDD1B) from Thorlabs Inc. was used and was held at a distance of 10 cm from the sample by placing the irradiation lamp on top of the quartz top of the chamber. The samples were exposed to UV light for 1 hour while being exposed to a continuous flow of MMA-saturated nitrogen.

[0190] After cleavage, the samples were removed from the chamber and carefully separated from the glass slides. Due to the evaporation edge effect, the edges of the samples were trimmed from the samples using a blade. The resulting samples were then exposed to a vacuum of -30 inches of mercury (inHg) at room temperature for 1 hour to remove any remaining MMA.

[0191] Second general method

[0192] Organic polysiloxane 2, MMA, and 1 wt.% photoinitiator were combined in a single liquid solution and then cured using UV irradiation to polymerize both components simultaneously. This forms a silicone-acrylate hybrid composition. Depending on, for example, the amount and / or type of components, the hybrid composition can have an opaque or translucent white color. Additionally, a similar range of mechanical properties as described in the first general method above can be achieved.

[0193] Comparative Example 2: Preparation of 100% PDMS elastomer

[0194] Prepare a stock solution of 3.0 milliliters (mL) of organic polysiloxane 2 and 0.03 mL of photoinitiator to provide a 100% PDMS sample.

[0195] Practical Examples 5 to Practical Example 9

[0196] Prepare different IPN samples from stock solutions with different amounts of organic polysiloxane 2 and different amounts of MMA. The stock solutions also have photoinitiator.

[0197] Table 3 - Simultaneous / "one-pot" IPN formation

[0198]

[0199]

[0200] To cure each sample in the sample set, sandwich the premixed solution between two 1 mm glass slides held together with a 1 mm thick Teflon spacer in between. Then place the sandwiched sample under a UV lamp with a wavelength of 375 nm and cure at an intensity of 1.7 milliwatts (mW / cm 2 ) for 30 minutes. After curing, remove the 1 mm thick sample using a blade.

[0201] Mechanical characterization procedure of the examples

[0202] Use 20 mm × 20 mm square samples with a target thickness of 1 mm for mechanical characterization. A caliper is used to measure the sample width and thickness, and then the width and thickness are recorded for each sample.

[0203] Load the sample into a tensile load setup using a TA Instruments power transducer. Parallel clamps are used to grip the square sample such that the gauge length is approximately 4 mm in height, at which point the instrument is adjusted so that the sample is placed under a preload tension of 0.05 Newtons (N). Then record the new gauge length based on the position offset from the preload procedure. Each sample in the sample set is tested twice using the same procedure.

[0204] Specifically, the sample is extended at a displacement rate of 10 millimeters per minute to a final displacement of 2 mm, and then the sample is held at that position for 30 seconds. During this procedure, the instrument records force and displacement values and exports the force and displacement values as a.csv file. Engineering strain is calculated based on the initial gauge length (approx. 4 mm) of the preloaded sample and the current displacement at any given time point. Engineering stress is calculated from the force readings and the initial cross-sectional area from the initially determined thickness and width of the sample.

[0205] First, the above tests are performed on the original sample. Secondly, the sample (assuming no fracture has occurred) is placed back in the fixture, and a notch is introduced perpendicular to the load direction after the preloading procedure. This is done using a disposable steel blade, and the crack is made at least 2 mm long and centered along the height of the sample. The sample is then extended again using the same procedure, and fracture of the sample is observed when the crack starts to propagate.

[0206] From this second test, the critical strain value is obtained from the load-displacement curve by finding the strain value at which the load starts to decrease (indicating when crack propagation and fracture start to occur). From the first (unnotched) test, the Young's modulus is calculated using the initial slope of the stress-strain curve. Finally, the fracture energy is calculated by assuming that the "pure shear" geometry used allows the following calculation to be valid:

[0207]

[0208] where Γ is the fracture energy in J / m 2 2h0 is the initial gauge length of the notched test, ε* is the critical strain value of the notched test, and σ(∈) is the stress-strain curve of the unnotched test.

[0209] Table 4 - Mechanical properties

[0210]

[0211] As described and illustrated herein, the present disclosure provides a method of producing a hybrid composition (e.g., a silicone-organic elastomeric material) that provides a substantial (e.g., up to 20x) increase in elastic modulus and fracture toughness relative to a pure silicone elastomer. Without being bound or limited by any particular theory, it is believed that these beneficial properties are achieved by restricting the length scale of phase separation. It is also believed that this provides a high degree of optical transparency. Additionally, the hybrid composition is composed of other immiscible polymers with large-scale homogeneity.

[0212] Accordingly, the present disclosure provides a solution to the situation where, for example, the limited toughness of conventional silicone elastomers for applications such as UV-curable conformal coatings and adhesives is problematic. For example, conventional blends or mixtures of different materials with high glass transition temperatures (Tg) have the potential to increase hardness, but typically suffer from a reduction in fracture toughness (embrittlement), and often result in "worst-case" performance due to large-scale phase separation.

[0213] The method of the present disclosure solves the problem of obtaining a toughened silicone-organic hybrid material that can be UV cured and provides the benefit of significantly enhanced fracture toughness while avoiding or minimizing the opacity associated with large-scale phase separation resulting from the immiscibility of organic polymers in the silicone matrix material.

[0214] The invention has been described by way of example, and it should be understood that the terms used are intended to be of a descriptive rather than restrictive nature. Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The invention may be practiced otherwise than as specifically described.

Claims

1. A method for preparing a silicone-acrylate hybrid composition, the method comprising: Combining a silicone article with an acrylate composition to form a swollen silicone article, wherein the acrylate composition is dispersed throughout the silicone article; and Irradiating the swollen silicone article to polymerize the acrylate composition and obtain a silicone-acrylate hybrid composition in the form of an interpenetrating polymer network (IPN) or a semi-interpenetrating polymer network (SIPN); Wherein the acrylate composition comprises: An acrylate compound having the general formula (A): Each R is independently selected from H and a substituted or unsubstituted hydrocarbon group, R 1 is H or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, n is an integer equal to or greater than 1, and R 2 is selected from R 1 , an amine group, an alkoxy group, an alkyl group, an alkyl group substituted with a hydroxyl group or an amino group; and An initiator; Wherein the step of irradiation is carried out in the absence of any solvent.

2. The method according to claim 1, wherein: (i) The acrylate composition further comprises a polyfunctional acrylate compound different from the acrylate compound of the general formula (A); (ii) The acrylate composition further comprises acrylic acid; (iii) R 2 is an alkoxy group; (iv) Each R is H; or (v) Any combination of (i) to (iv).

3. The method according to any one of claims 1 to 2, wherein the silicone-acrylate hybrid composition comprises a silicone article and an acrylate polymer, and wherein: (i) The silicone article and the acrylate polymer are at least partially physically interpenetrated; (ii) The silicone article and the acrylate polymer are chemically bonded to each other; Or (iii) both (i) and (ii).

4. A silicone-acrylate hybrid composition, the silicone-acrylate hybrid composition being formed by the method according to any one of claims 1 to 3.

5. A composite article, the composite article comprising the silicone-acrylate hybrid composition according to claim 4 disposed on a substrate.

6. The composite article according to claim 5, wherein the substrate comprises an electronic device.

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