Curable composition and method of forming cured product

Abstract

A curable composition comprising: (A) an organopolysiloxane having on average, per molecule, at least two aliphatic unsaturations bonded to silicon; (B) an organopolysiloxane which does not contain aliphatic unsaturated groups and has an average of at least two mercapto groups per molecule; (C) a photoinitiator; (D) an acryloyloxy functionalized silane; and (E) a tetraorthosilicate ester.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and all advantages of U.S. Provisional Patent Application No. 63 / 393,964, filed on July 31, 2022, the contents of which are incorporated herein by reference. Technical Field

[0003] The subject disclosure relates generally to curable compositions, and more particularly to curable silicone compositions that can be cured by exposure to radiation to yield a cured product having excellent adhesion to substrates, and to related methods and articles. Background Art

[0004] Curable organopolysiloxane compositions are known in the art and are used in numerous industries. Curable organopolysiloxane compositions can be cured via different curing conditions, depending on the functional groups present in or on the components of such curable organopolysiloxane compositions. Common curing conditions include exposure to heat, moisture, irradiation, etc. Different end-use applications typically dictate the specific curing conditions used, for example, certain curable organopolysiloxane compositions are used in end-use applications where exposure to heat is undesirable. This is particularly true for certain electronic applications, where it is undesirable to expose electronic components to elevated temperatures.

[0005] UV curing of organopolysiloxane compositions is often used to prepare cured products that require curing in the absence of heat. In addition, certain substrates on which the cured product is formed may have complex geometries or surface characteristics that create shadow areas that are difficult to cure via UV radiation. Therefore, it is often necessary to utilize a dual cure system that can cure via both UV radiation and moisture (or another curing mechanism that does not require elevated temperatures).

[0006] Certain types of functional groups are known to be capable of UV curing upon exposure to radiation, including certain epoxy-functional organopolysiloxane compositions, acrylate-functional organopolysiloxane compositions, and thiol-ene-functional organopolysiloxane compositions. Thiol-ene-functional organopolysiloxane compositions are known to cure very quickly, including when compared to other functional groups known to be capable of UV curing. Additionally, unlike acrylate-functional organopolysiloxane compositions, thiol-ene-functional organopolysiloxane compositions are not inhibited by ambient oxygen, which further speeds up their cure speed under ambient conditions. However, while conventional thiol-ene-functional organopolysiloxane compositions are capable of very rapid curing, they have poor or undesirable adhesion to substrates when cured to form a cured product, often with adhesion failure occurring upon removal from the substrate, which limits their usefulness. Summary of the invention

[0007] A curable composition is disclosed. The curable composition comprises (A) an organopolysiloxane having an average of at least two silicon-bonded aliphatic unsaturated groups per molecule. The composition further comprises (B) an organopolysiloxane having no aliphatic unsaturated groups and having an average of at least two mercapto groups per molecule. The composition further comprises (C) a photoinitiator. In addition, the composition comprises (D) an acryloxy-functional silane represented by the following formula:

[0008]

[0009] Where X is a divalent hydrocarbon group, each R is independently a hydrocarbon group, and each R 1 is independently an alkyl group having 1 to 8 carbon atoms, the subscript x is 2 or 3, and R 2 H or R 1 Finally, the composition comprises (E) a tetraorthosilicate of the formula: Si(OR 3 ) 4 , where each R 3 is independently an alkyl group having 1 to 10 carbon atoms.

[0010] A method for forming a cured product is also disclosed. The method includes the step of applying a composition to a surface of a substrate. The method also includes the step of irradiating the composition on the substrate to obtain a cured product. A cured product disposed on a substrate formed according to the method is also disclosed. DETAILED DESCRIPTION

[0011] Disclosed below are curable compositions ("compositions"), methods of forming cured products on substrates using the compositions, and cured products formed thereby. The compositions form cured products having excellent adhesion to substrates and can be used in a variety of end-use applications.

[0012] The composition comprises (A) an organopolysiloxane having an average of at least two silicon-bonded aliphatically unsaturated groups per molecule. As will be appreciated by those skilled in the art, an organopolysiloxane comprises inorganic silicon-oxygen-silicon groups (i.e., -Si-O-Si-) wherein organosilicon and / or organic side groups are attached to silicon atoms in M, D and / or T siloxy units. Organopolysiloxanes are typically characterized by the number, type and / or ratio of [M], [D], [T] and / or [Q] units per siloxy group (each of which represents a structural unit for a respective functional group present in the organopolysiloxane resin). Specifically, [M] represents the general formula R" 3 SiO 1 / 2 [D] represents a monofunctional unit of the general formula R" 2 SiO 2 / 2 [T] represents the general formula R"SiO 3 / 2[Q] represents a trifunctional unit of the general formula SiO 4 / 2 The tetrafunctional unit is shown in the following general structure:

[0013]

[0014] In these general structural parts, each R" is independently a monovalent or polyvalent substituent. As understood in the art, there is no particular limitation on the specific substituents suitable for each R" (e.g., it can be monatomic or polyatomic, organic or inorganic, linear or branched, substituted or unsubstituted, aromatic, aliphatic, saturated or unsaturated, etc., and various combinations thereof).

[0015] Those skilled in the art understand how [M], [D], [T], and [Q] units and their relative proportions (i.e., mole fractions) affect and control the structure of the siloxane, and polysiloxanes can generally be monomeric, polymeric, oligomeric, linear, branched, partially branched, hyperbranched, cyclic, dendritic, and / or resinous, depending on the selection of [M], [D], [T], and / or [Q] units therein. For example, [T] units and / or [Q] units are present in an organopolysiloxane resin, whereas linear organopolysiloxanes generally do not contain such [T] units and / or [Q] units.

[0016] As described above, the (A) organopolysiloxane has an average of at least two silicon-bonded aliphatic unsaturated groups per molecule. The silicon-bonded aliphatic unsaturated groups may independently be alkenyl and / or 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 aliphatic unsaturated groups suitable for (A) organopolysiloxane include CH 2 =CH—, CH 2 =CHCH 2 —、CH 2 =CH(CH 2 ) 4 —、CH 2 =CH(CH 2 ) 6 —、CH 2 =C(CH 3 )CH 2 —、H 2 C=C(CH 3 )—、H 2 C=C(CH 3 )—、H 2C=C(CH 3 )CH 2 —、H 2 C=CHCH 2 CH 2 —、H 2 C=CHCH 2 CH 2 CH 2 —、HC≡C—、HC≡CCH 2 —HC≡CCH(CH 3 )—、HC≡CC(CH 3 ) 2 — and HC≡CC(CH 3 ) 2 CH 2 —. Typically, the aliphatic unsaturation is at the terminal end of each aliphatic unsaturated group. As understood in the art, aliphatic unsaturation may be referred to as olefinic unsaturation.

[0017] The (A) organopolysiloxane is not limited and can be any organopolysiloxane containing an average of at least two silicon-bonded aliphatically unsaturated groups per molecule. For example, the (A) organopolysiloxane can be linear, branched, partially branched, cyclic, resinous (i.e., having a three-dimensional network), or can include a combination of different structures.

[0018] In certain embodiments, the (A) organopolysiloxane has the following average formula:

[0019] R q’ SiO (4-q’) / 2 ,

[0020] wherein each R is an independently selected substituted or unsubstituted hydrocarbon group, provided that on average per molecule, at least two R groups are independently selected aliphatically unsaturated groups, and wherein q' is selected such that 0 <a’≤3.2。

[0021] In certain embodiments, the (A) organopolysiloxane is represented by the following average formula:

[0022] (R 4 3-m R 5 m SiO 1 / 2 ) a (R 4 2-n R 5 n SiO 2 / 2 ) b (R 5 SiO 3 / 2 ) c (SiO4 / 2 ) d (ZO 1 / 2 ) e , where each R 4 is an independently selected substituted or unsubstituted hydrocarbon group having no aliphatic unsaturation; each R 5 Independently for R 4 or an aliphatic unsaturated group having 1 to 10 carbon atoms; each subscript m is independently an integer from 0 to 3 in each unit indicated by subscript a; each subscript n is an integer from 0 to 2 in each unit indicated by subscript b; provided that at least two R 5 is an aliphatic unsaturated group; each Z is independently H or an alkyl group; and wherein a, b, c, d, and e are mole fractions satisfying the following conditions: a>0; b>0; c≥0; d≥0; 0≤e≤0.05; and a+b+c+d+e=1. Those skilled in the art understand how these M, D, T, and Q units and their mole fractions affect the subscript f in the above average formula. The T and Q units indicated by the subscripts c and d, respectively, are typically present in silicone resins, while the D units indicated by the subscript b are typically present in silicone polymers (and may also be present in silicone resins).

[0023] Usually, for R 4 The hydrocarbyl groups of R can independently be linear, branched, cyclic or a combination thereof. 4 Does not have aliphatic unsaturation, that is, each R 4It is not an alkenyl or alkynyl group. The cyclic hydrocarbon group includes an aryl group and a saturated or non-conjugated cyclic group. The cyclic hydrocarbon group can be independently monocyclic or polycyclic. An example of the combination of linear and cyclic hydrocarbon groups is an aralkyl group. General examples of hydrocarbon groups include alkyl groups, aryl groups, halogenated carbon groups, etc., and their derivatives, modifications and combinations. The example of a suitable alkyl group includes methyl, ethyl, propyl (such as isopropyl and / or n-propyl), butyl (such as isobutyl, n-butyl, tert-butyl and / or sec-butyl), pentyl (such as isopentyl, neopentyl and / or tert-pentyl), hexyl, hexadecyl, octadecyl, and a branched saturated hydrocarbon group with 6 to 18 carbon atoms. The example of a suitable non-conjugated cyclic group includes cyclobutyl, cyclohexyl and cycloheptyl groups. The example of a suitable aryl group includes phenyl, tolyl, xylyl, naphthyl, benzyl and dimethylphenyl. The example of suitable monovalent halogenated hydrocarbon group (that is, halogenated hydrocarbon group or substituted hydrocarbon group) includes halogenated alkyl group, aryl group and their combination.The example of halogenated alkyl group includes the alkyl group in which one or more hydrogen atoms are replaced by halogen atoms such as F or Cl.The specific example of halogenated alkyl group includes 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, and their derivatives. Examples of halogenated aryl groups include the above aryl groups in which one or more hydrogen atoms are replaced by halogen atoms such as F or Cl. Specific examples of halogenated aryl groups include chlorobenzyl and fluorobenzyl groups. In a specific embodiment, each R 4 is independently an alkyl group having 1 to 10 carbon atoms, alternatively 1 to 8 carbon atoms, alternatively 1 to 6 carbon atoms, alternatively 1 to 4 carbon atoms, alternatively 1 to 2 carbon atoms, alternatively each R 4 A methyl group.

[0024] Each R 5 Independently for R 4 or an aliphatic unsaturated group having 1 to 10 carbon atoms. Suitable examples of aliphatic unsaturated groups are described above. Each subscript m is independently an integer from 0 to 3 in each unit indicated by subscript a. Subscript a indicates an M siloxy unit, and thus each M siloxy unit is independently selected. For example, (A) an organopolysiloxane may include a trimethylsiloxy unit as an M unit (i.e., when subscript m is 0 and each R 4methyl), dimethylvinylsiloxy units as M units (ie, when the subscript m is 1, each R 4 is methyl and R 5 is vinyl), methyl divinylsiloxy units as M units (ie, when the subscript m is 2, R 4 is methyl and each R 5 is vinyl) and / or trivinylsiloxy units as M units (ie, when the subscript m is 3 and each R 5 for vinyl).

[0025] Similarly, each subscript n is an integer from 0 to 2 in each unit represented by subscript b. Subscript b indicates a D siloxy unit, and thus each D siloxy unit is independently selected. For example, the (A) organopolysiloxane may include a dimethylsiloxy unit as a D unit (i.e., when subscript n is 0 and each R 4 methyl), phenylmethylsiloxy units as D units (ie, when subscript n is 0, one R 4 is methyl and the other R 4 phenyl), methylvinylsiloxy units as D units (ie, when subscript n is 1, R 4 is methyl and R 5 is vinyl) and / or divinylsiloxy units as D units (ie, when the subscript n is 2 and each R 5 Those skilled in the art understand how each methyl group can be substituted with another hydrocarbyl group (which is optionally substituted) and how each vinyl group can be substituted with another aliphatically unsaturated group.

[0026] The subscript e indicates the SiOZ content of the (A) organopolysiloxane. The SiOZ content can be SiOH (or silanol groups, where Z is H) or alkoxy groups bonded to silicon (where Z is an alkyl group). In other words, each Z is independently H or an alkyl group. For example, "(SiO 4 / 2 )(ZO 1 / 2 )" refers to a Q3-type group in which the silicon atom is bonded to the "Z" group via a single oxygen. Under NMR nomenclature, such "(SiO 4 / 2 )(ZO 1 / 2)" portion is still considered to be a Q siloxy unit. When Z is an alkyl group, the alkyl group is typically C1 to C8, alternatively C1 to C6, alternatively C1 to C4, alternatively C1 to C2, alternatively a C1 (i.e., methyl) alkyl group. In the (A) organopolysiloxane, 0≤e≤0.05, alternatively 0≤e≤0.04, alternatively 0≤e≤0.03, alternatively 0≤e≤0.02, alternatively 0≤e≤0.01, alternatively e is 0. When the (A) organopolysiloxane is linear or branched, the subscript e is typically 0, but when the (A) organopolysiloxane is resinous, the subscript e may be>0. Such SiOZ portions are typically inherently present in silicone resins prepared by hydrolysis and condensation of silanes.

[0027] In a specific embodiment, (A) organopolysiloxane is resinous. When (A) organopolysiloxane is resinous, subscript c>0 and / or subscript d>0, so that (A) organopolysiloxane comprises at least some T and / or Q siloxy units, respectively. In one embodiment, c>0 and d is 0. In another embodiment, c is 0 and d>0. In some other embodiments, c and d are each>0. In these embodiments, (A) organopolysiloxane has a branched or three-dimensional network molecular structure. At 25°C, (A) organopolysiloxane may be in liquid or solid form. Alternatively, examples of (A) organopolysiloxane may include: a polyorganosiloxane comprising only T units, a polyorganosiloxane comprising a combination of T units and other siloxy units (e.g., M, D and / or Q siloxy units), or a polyorganosiloxane comprising a combination of Q units and other siloxy units (i.e., M, D and / or T siloxy units). Specific examples of resinous organopolysiloxanes suitable for (A) organopolysiloxane include vinyl-terminated silsesquioxanes (ie, T resins) and vinyl-terminated MDQ resins. Alternatively, (A) organopolysiloxane may include branched siloxanes, silsesquioxanes, or both branched siloxanes and silsesquioxanes.

[0028] When the (A) organopolysiloxane is branched, the (A) organopolysiloxane may have the following unit formula: (R 4 3- m R 5 m SiO 1 / 2 ) a (R 4 2-n R 5 n SiO 2 / 2 ) b (SiO 4 / 2 ) d (ZO 1 / 2 ) e, where each R 4 are independently selected and as defined above, each R 5 are independently selected and as defined above, subscript a>0, subscript b>0, subscript d>0, and subscript e≤0.05. The (A) organopolysiloxane may comprise a single Q siloxy unit or two or more Q siloxy units, which may optionally be clustered or bonded together.

[0029] When the (A) organopolysiloxane is branched, the (A) organopolysiloxane may include at least two 4 2 SiO 2 / 2 ) m wherein each subscript m is independently 2 to 5000. Alternatively, when the (A) organopolysiloxane is branched, the (A) organopolysiloxane may comprise a polydiorganosiloxane chain bonded to four 4 2 SiO 2 / 2 ) o The polydiorganosiloxane chain has at least one formula (SiO 4 / 2 ) wherein each subscript o is independently 1 to 2500.

[0030] However, (A) organopolysiloxanes are generally free of such T and Q siloxy units. "At least some" means that (A) organopolysiloxanes may contain up to 5 mol%, alternatively up to 4 mol%, alternatively up to 3 mol%, alternatively up to 2 mol%, alternatively up to 1 mol%, alternatively 0 mol% of T and Q siloxy units based on all siloxy units present in (A) organopolysiloxane. Typically, (A) organopolysiloxanes are flowable liquids at room temperature, including in the absence of any solvent or carrier vehicle, rather than gums or resins, in view of the required viscosity. Although gums or resins may be liquids at room temperature when dissolved or dispersed in a solvent or carrier fluid, such solvents may be undesirable in certain end-use applications because the solvent is typically volatilized or otherwise removed during the curing process.

[0031] In certain embodiments, the (A) organopolysiloxane is substantially linear. Substantially linear means that component (A) comprises, consists essentially of, or consists only of M and D siloxy units. As is readily understood in the art, the M siloxy units are of the formula (R 4 3-m R 5 m SiO 1 / 2 ) and the D siloxy unit is of formula (R 4 2-n R5 n SiO 2 / 2 ), where the subscripts m and n and R 4 and R 5 As defined above. Traditionally, the M and D siloxy nomenclature is used only in conjunction with methyl substitution. However, for the purposes of this disclosure, in the above-described M and D siloxy units, each R 4 and R 5 As defined above and not necessarily a methyl group. When the M siloxy unit contains at least one silicon-bonded aliphatic unsaturated group, the silicon-bonded aliphatic unsaturated group is a terminal group. When the D siloxy unit contains at least one silicon-bonded aliphatic unsaturated group, the silicon-bonded aliphatic unsaturated group is a pendant group.

[0032] In a specific embodiment where the (A) organopolysiloxane is substantially linear, the (A) organopolysiloxane is represented by the following average formula:

[0033] (R 4 3-m R 5 m SiO 1 / 2 ) 2 (R 4 2-n R 5 n SiO 2 / 2 ) y ,

[0034] wherein the subscript y is an integer from 10 to 10000; and R 4 , R 5 and subscripts m and n are independently selected and as defined above. The value of subscript y is from 10 to 10000. In one embodiment, subscript y is from 10 to 10000, alternatively from 10 to 9000, alternatively from 10 to 8000, alternatively from 10 to 7000, alternatively from 10 to 6000, alternatively from 10 to 5000, alternatively from 10 to 4000, alternatively from 10 to 3000, alternatively from 10 to 2000, alternatively from 10 to 1000, alternatively from 50 to 900. When (A) organopolysiloxane is substantially linear, the value of subscript y may be referred to as the degree of polymerization (DP) of (A) organopolysiloxane.

[0035] When the (A) organopolysiloxane is substantially linear, alternatively linear, at least two aliphatically unsaturated groups may be bonded to the silicon atom in a pendant position, a terminal position, or both a pendant position and a terminal position.

[0036] In one embodiment, when the (A) organopolysiloxane is substantially linear, each subscript m is 1 and each subscript n is 0, such that the (A) organopolysiloxane is represented by the following average formula: 4 2 R 5 SiO 1 / 2 ) 2 (R 4 2 SiO 2 / 2 ) y For example, as a specific example of the (A) organopolysiloxane having an average of at least two silicon-bonded aliphatic unsaturated groups per molecule, the (A) organopolysiloxane may have the following average formula: Vi(CH 3 ) 2 SiO[(CH 3 ) 2 SiO] y Si(CH 3 ) 2 Vi, wherein the subscripts y and Vi are as defined above. For this average formula, any methyl group may be replaced by a different monovalent hydrocarbon group, and any vinyl group may be replaced by any terminal aliphatically unsaturated monovalent hydrocarbon group.

[0037] As specific examples of the (A) organopolysiloxane having a silicon-bonded aliphatic unsaturated group at a side chain, the (A) organopolysiloxane may have the following average unit formula:

[0038] [(CH 3 ) 3 SiO 1 / 2 ] 2 [(CH 3 ) 2 SiO 2 / 2 ] cc [(CH 3 )ViSiO 2 / 2 ] bb ,

[0039] wherein subscript bb is 2 to 20, alternatively 2 to 10, subscript cc is 8 to 9980, and Vi represents a vinyl group. With respect to this average formula, any methyl group may be replaced by a different monovalent hydrocarbon group such as an alkyl or aryl group, and any vinyl group may be replaced by a different aliphatic unsaturated monovalent hydrocarbon group such as an allyl or hexenyl group.

[0040] Since the at least two silicon-bonded aliphatically unsaturated groups may be either pendant or terminal, the (A) organopolysiloxane may alternatively have an average unit formula:

[0041] [Vi(CH 3 )2 SiO 1 / 2 ] 2 [(CH 3 ) 2 SiO 2 / 2 ] cc [(CH 3 )ViSiO 2 / 2 ] bb or

[0042] [Vi(CH 3 ) 2 SiO 1 / 2 ][(CH 3 ) 3 SiO 1 / 2 ][(CH 3 ) 2 SiO 2 / 2 ] cc [(CH 3 )ViSiO 2 / 2 ] bb , wherein the subscripts bb and cc and Vi are as defined above.

[0043] When the (A) organopolysiloxane is a substantially linear polyorganosiloxane, examples of the (A) organopolysiloxane may include: dimethylpolysiloxane capped at both molecular ends with dimethylvinylsiloxy groups; methylphenylpolysiloxane capped at both molecular ends with dimethylvinylsiloxy groups; a copolymer of methylphenylsiloxane and dimethylsiloxane capped at both molecular ends with dimethylvinylsiloxy groups; a copolymer of methylvinylsiloxane and methylphenylsiloxane capped at both molecular ends with dimethylvinylsiloxy groups; The invention relates to a copolymer of methylvinylsiloxane and diphenylsiloxane terminated with a methylvinylsiloxane group; a copolymer of methylvinylsiloxane, methylphenylsiloxane and dimethylsiloxane terminated with a dimethylvinylsiloxy group at both ends of the molecule; a copolymer of methylvinylsiloxane and methylphenylsiloxane terminated with a trimethylsiloxy group at both ends of the molecule; a copolymer of methylvinylsiloxane and diphenylsiloxane terminated with a trimethylsiloxy group at both ends of the molecule; and a copolymer of methylvinylsiloxane, methylphenylsiloxane and dimethylsiloxane terminated with a trimethylsiloxy group at both ends of the molecule.

[0044] Alternatively, (A) the organopolysiloxane may comprise a substantially linear, alternatively linear, polyorganosiloxane selected from the group consisting of:

[0045] i) dimethylvinylsiloxy-terminated polydimethylsiloxane,

[0046] ii) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane),

[0047] iii) dimethylvinylsiloxy-terminated polymethylvinylsiloxane,

[0048] iv) trimethylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane),

[0049] v) trimethylsiloxy-terminated polymethylvinylsiloxane,

[0050] vi) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane),

[0051] vii) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylphenylsiloxane),

[0052] viii) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / diphenylsiloxane),

[0053] ix) phenyl, methyl, vinyl-siloxy-terminated polydimethylsiloxane,

[0054] x) dimethylhexenylsiloxy-terminated polydimethylsiloxane,

[0055] xi) dimethylhexenylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane),

[0056] xii) dimethylhexenylsiloxy-terminated polymethylhexenylsiloxane,

[0057] xiii) trimethylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane),

[0058] xiv) trimethylsiloxy-terminated polymethylhexenylsiloxane,

[0059] xv) dimethylhexenylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane),

[0060] xvi) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane),

[0061] xvii) dimethylvinylsiloxy-terminated polymethylphenylsiloxane,

[0062] xviii) dimethylvinylsiloxy-terminated polydimethylsiloxane / methylphenylsiloxane, and

[0063] xix) their combination.

[0064] The (A) organopolysiloxane may include a combination of two or more different polyorganosiloxanes that differ in at least one characteristic such as structure, molecular weight, degree of polymerization, content of monovalent groups bonded to silicon atoms, and aliphatic unsaturated groups.

[0065] For example, in one embodiment, (A) the organopolysiloxane may include (A1) a first organopolysiloxane and (A2) a second organopolysiloxane. (A1) The first organopolysiloxane and (A2) The second organopolysiloxane are different from each other. In one embodiment, (A1) The first organopolysiloxane is linear and (A2) The second organopolysiloxane is not linear. In other embodiments, (A1) The first organopolysiloxane and (A2) The second organopolysiloxane are both linear.

[0066] Typically, the (A1) first organopolysiloxane and the (A2) second organopolysiloxane each have an average of at least two silicon-bonded aliphatically unsaturated groups per molecule. In some embodiments, the (A1) first organopolysiloxane and the (A2) second organopolysiloxane both have the same general formula but differ only in degree of polymerization. The (A1) first organopolysiloxane and the (A2) second organopolysiloxane may each independently be linear, substantially linear, branched, substantially branched, resinous, or substantially resinous.

[0067] In embodiments where the (A1) first organopolysiloxane is linear, the (A1) first organopolysiloxane may have a degree of polymerization of 10 to 10,000, alternatively 10 to 9,000, alternatively 10 to 8,000, alternatively 10 to 7,000, alternatively 10 to 6,000, alternatively 10 to 5,000, alternatively 10 to 4,000, alternatively 10 to 3,000, alternatively 10 to 2,000, alternatively 250 to 1,500, alternatively 500 to 1,000, alternatively 600 to 900, alternatively 700 to 800. In these or other embodiments where the (A2) second organopolysiloxane is linear, the (A2) second organopolysiloxane has a degree of polymerization of 10 to 10,000, alternatively 10 to 7,500, alternatively 10 to 5,000, alternatively 10 to 2,500, alternatively 10 to 1,000, alternatively 10 to 750, alternatively 50 to 500, alternatively 50 to 300, alternatively 100 to 200.

[0068] The (A1) first organopolysiloxane and the (A2) second organopolysiloxane may independently have terminal and / or pendant silicon-bonded aliphatic unsaturated groups. In some embodiments, the (A1) first organopolysiloxane and the (A2) second organopolysiloxane do not have pendant silicon-bonded aliphatic unsaturated groups.

[0069] When (A) the organopolysiloxane comprises (A1) a first organopolysiloxane and (A2) a second organopolysiloxane, the weight ratio of (A1) the first organopolysiloxane to (A2) the second organopolysiloxane is not limited. In some embodiments, the weight ratio of (A1) the first organopolysiloxane to (A2) the second organopolysiloxane is 100:1 to 1:100, alternatively 50:1 to 1:50, alternatively 25:1 to 1:25, alternatively 10:1 to 1:10, alternatively 5:1 to 1:5, alternatively 3:1 to 1:3, alternatively 2:1 to 1:2, alternatively 1.5:1 to 1:1.5, alternatively 1.2:1 to 1:1.2, alternatively 1.1:1 to 1:1.1, or alternatively 1.15:1 to 1:1.15. In certain embodiments, in certain embodiments where (A) the organopolysiloxane comprises (A1) a first organopolysiloxane and (A2) a second organopolysiloxane, (A1) the first organopolysiloxane is present in the composition in an amount of 1% to 89% by weight, alternatively 10% to 80% by weight, alternatively 20% to 60% by weight, alternatively 20% to 40% by weight, alternatively 25% to 35% by weight, alternatively 28% to 32% by weight, based on the total weight of the composition. In these or other embodiments, (A2) the second organopolysiloxane is present in the composition in an amount of 1% to 89% by weight, alternatively 10% to 80% by weight, alternatively 20% to 60% by weight, alternatively 20% to 40% by weight, alternatively 25% to 35% by weight, alternatively 30% to 35% by weight, based on the total weight of the composition.

[0070] Regardless of the choice of (A) organopolysiloxane, (A) organopolysiloxane is typically present in the composition in an amount of 5 to 95 wt%, alternatively 10 to 90 wt%, alternatively 20 to 90 wt%, alternatively 30 to 90 wt%, alternatively 50 to 90 wt%, based on the total weight of the composition. In a specific embodiment, (A) organopolysiloxane is present in the composition in an amount of 10 to 80 wt%, alternatively 20 to 70 wt%, alternatively 20 to 80 wt%, alternatively 30 to 70 wt%, alternatively 40 to 70 wt%, alternatively 50 to 70 wt%, alternatively 55 to 65 wt%, based on the total weight of the composition.

[0071] The composition further comprises (B) an organopolysiloxane having no aliphatic unsaturated groups and having an average of at least two mercapto groups per molecule.

[0072] (B) organopolysiloxane is not limited and can be any organopolysiloxane containing at least two mercapto groups per molecule on average. For example, (B) organopolysiloxane can be linear, branched, partially branched, hyperbranched, cyclic, tree-like, resinous (i.e., having a three-dimensional network), or can contain a combination of different structures. At least two mercapto groups in component (B) are reactive with the silicon-bonded aliphatic unsaturated groups in component (A). The mercapto groups mentioned herein include any group having a mercapto functional group, for example, mentioning a mercapto group includes mentioning a mercaptoalkyl group, not just a -SH group.

[0073] In certain embodiments, the (B) organopolysiloxane has the following average formula:

[0074] R' q” SiO (4-q”) / 2 ,

[0075] wherein each R' is an independently selected substituted or unsubstituted hydrocarbon group having no aliphatic unsaturation, provided that on average per molecule, at least two R' groups are independently selected thiol functional groups, and wherein qq" is selected such that 0 <q”≤3.2。

[0076] In some embodiments, the (B) organopolysiloxane is represented by the following average formula:

[0077] (R 4 3-o R 6 o SiO 1 / 2 ) f (R 4 2-p R 6 p SiO 2 / 2 ) g (R 6 SiO 3 / 2 ) h (SiO 4 / 2 ) i (ZO 1 / 2 ) j ,

[0078] Each R 4 is an independently selected substituted or unsubstituted hydrocarbon group having no aliphatic unsaturation; each R 6 Independently for R 4 or contains a thiol group; subscript o is independently an integer from 0 to 3 in each unit indicated by subscript f; each p is independently an integer from 0 to 2 in each unit indicated by subscript f; provided that at least two R 6Independently contains a thiol group; each Z is independently H or an alkyl group; wherein f, g, h, i and j are molar fractions that satisfy the following conditions: f>0; g>0; h≥0; i≥0; 0≤j≤0.05 and f+g+h+i+j=1.

[0079] R 4 Suitable examples of are as described above in relation to component (A).

[0080] Each R 6 Independently for R 4 Or contain a thiol group. 6 Each thiol group of can be any group containing a thiol (SH) functional group. In certain embodiments, R 6 Each thiol group is independently of the formula -X 1 -SH, where X 1 is a divalent hydrocarbon group. In these embodiments, X 1 Exists between the silicon atom of component (B) and the sulfur atom of the mercapto group. 1 is chosen so that R 6 In these embodiments, each mercapto group of is a mercaptoalkyl group. 6 Each thiol group can be written as (CH 2 ) t SH, wherein subscript t is independently 1 to 10, alternatively 1 to 9, alternatively 1 to 8, alternatively 1 to 7, alternatively 2 to 6. Examples of divalent hydrocarbon groups when subscript t is 1 to 8 include: alkylene groups with 1 to 8 carbon atoms, such as methylene groups, ethylene groups, propylene groups, butylene groups, pentylene groups, hexylene groups, heptylene groups and octylene groups. Those skilled in the art will appreciate that based on the description of X 1 The corresponding thiol group is obtained by selecting. For example, when the subscript t is 3, the corresponding thiol group is a 3-mercaptopropyl group; when the subscript t is 4, the corresponding thiol group is a 4-mercaptobutyl group; when the subscript t is 6, the corresponding thiol group is a 6-mercaptohexyl group. Each thiol group is not necessarily a primary thiol group. For example, each thiol group can be independently primary, secondary or tertiary. In certain embodiments, each thiol group is primary.

[0081] Each subscript o is independently an integer from 0 to 3 in each unit indicated by subscript f. Subscript f indicates an M siloxy unit, and thus each M siloxy unit is independently selected. For example, the (B) organopolysiloxane may include a trimethylsiloxy unit as an M unit (i.e., when subscript o is 0 and each R 4 is methyl), dimethylmercaptosiloxy units as M units (ie, when subscript o is 1, each R 4 is methyl and R6 is a mercapto group), a methyldimercaptosiloxy unit as an M unit (ie, when the subscript o is 2, R 4 is methyl and each R 6 is a mercapto group) and / or a trimercaptosiloxy unit as an M unit (ie, when the subscript o is 3 and each R 6 is a thiol group).

[0082] Similarly, each subscript p is an integer from 0 to 2 in each unit represented by subscript g. Subscript p indicates a D siloxy unit, and thus each D siloxy unit is independently selected. For example, the (B) organopolysiloxane may include a dimethylsiloxy unit as a D unit (i.e., when subscript p is 0 and each R 4 is methyl), methylmercaptosiloxy units as D units (ie, when the subscript p is 1, R 4 is methyl and R 6 is a mercapto group) and / or a dimercaptosiloxy unit as a D unit (ie, when the subscript p is 2 and each R 6 Those skilled in the art understand how each methyl group can be substituted with another hydrocarbyl group (which is optionally substituted) and how each thiol group can be substituted with another aliphatic thiol group.

[0083] The subscript j indicates the SiOZ content of the (B) organopolysiloxane. The SiOZ content can be SiOH (where Z is H or a silanol group) or alkoxy groups bonded to silicon (where Z is an alkyl group). In other words, each Z is independently H or an alkyl group. For example, "(SiO 4 / 2 )(ZO 1 / 2 )" refers to a Q-type group in which the silicon atom is bonded to the "Z" group via a single oxygen. Under NMR nomenclature, such "(SiO 4 / 2 )(ZO 1 / 2 )" portion is still considered to be a Q siloxy unit. When Z is an alkyl group, the alkyl group is typically C1 to C8, alternatively C1 to C6, alternatively C1 to C4, alternatively C1 to C2, alternatively a C1 (i.e., methyl) alkyl group. In the (B) organopolysiloxane, 0≤j≤0.05, alternatively 0≤j≤0.04, alternatively 0≤j≤0.03, alternatively 0≤j≤0.02, alternatively 0≤j≤0.01, alternatively j is 0. When the (B) organopolysiloxane is linear or branched, the subscript j is typically 0, but when the (B) organopolysiloxane is resinous, the subscript j may be>0. Such SiOZ portions are typically inherently present in silicone resins prepared by hydrolysis and condensation of silanes.

[0084] In a specific embodiment, (B) organopolysiloxane is resinous. When (B) organopolysiloxane is resinous, subscript h>0 and / or subscript i>0, so that (B) organopolysiloxane comprises at least some T and / or Q siloxy units, respectively. In one embodiment, h>0 and i is 0. In another embodiment, h is 0 and i>0. In some other embodiments, h and i are each>0. In these embodiments, (B) organopolysiloxane has a branched or three-dimensional network molecular structure. At 25°C, (B) organopolysiloxane may be in liquid or solid form. Alternatively, examples of (B) organopolysiloxane may include: a polyorganosiloxane comprising only T units, a polyorganosiloxane comprising a combination of T units and other siloxy units (e.g., M, D and / or Q siloxy units), or a polyorganosiloxane comprising a combination of Q units and other siloxy units (i.e., M, D and / or T siloxy units). Specific examples of resinous organopolysiloxanes suitable for (B) organopolysiloxane include mercapto-terminated silsesquioxanes (ie, T resins) and mercapto-terminated MDQ resins. Alternatively, (B) organopolysiloxane may include branched siloxanes, silsesquioxanes, or both branched siloxanes and silsesquioxanes.

[0085] However, (B) organopolysiloxanes are generally free of such T and Q siloxy units. By "at least some", it is meant that (B) organopolysiloxanes may include up to 5 mol%, alternatively up to 4 mol%, alternatively up to 3 mol%, alternatively up to 2 mol%, alternatively up to 1 mol%, alternatively 0 mol% of T and Q siloxy units based on all siloxy units present in (B) organopolysiloxanes. Typically, (B) organopolysiloxanes are flowable liquids at room temperature, including in the absence of any solvent or carrier vehicle other than gum or resin, taking into account the required viscosity. Although gum or resin may be liquid at room temperature when dissolved or dispersed in a solvent or carrier fluid, such solvents may be undesirable in certain end-use applications because the solvent is typically volatilized or otherwise removed during the curing process.

[0086] In certain embodiments, (B) organopolysiloxane is substantially linear. By substantially linear, it is meant that component (B) comprises, consists essentially of, or consists only of M and D siloxy units. As is readily understood in the art, the M siloxy units are of the formula (R 4 3-o R 6 o SiO 1 / 2 ) and the D siloxy unit is of formula (R 4 2-p R 6p SiO 2 / 2 ), where the subscripts o and p and R 4 and R 6 As defined above. Traditionally, the M and D siloxy nomenclature is used only in conjunction with methyl substitution. However, for the purposes of this disclosure, in the above-described M and D siloxy units, each R 4 and R 6 As defined above and not necessarily a methyl group. When the M siloxy unit comprises at least one thiol group, the thiol group is a terminal group. When the D siloxy unit comprises at least one thiol group, the thiol group is a pendant group.

[0087] In a specific embodiment where the (B) organopolysiloxane is substantially linear, the (B) organopolysiloxane is represented by the following average formula:

[0088] (R 4 3-o R 6 o SiO 1 / 2 ) 2 (R 4 2-p R 6 p SiO 2 / 2 ) z ,

[0089] wherein the subscript z is an integer from 10 to 10000; and R 4 , R 6 and subscripts o and p are independently selected and as defined above. The value of subscript z is from 10 to 10,000. In one embodiment, subscript z is from 10 to 10,000, alternatively from 10 to 9,000, alternatively from 10 to 8,000, alternatively from 10 to 7,000, alternatively from 10 to 6,000, alternatively from 10 to 5,000, alternatively from 10 to 4,000, alternatively from 10 to 3,000, alternatively from 10 to 2,000, alternatively from 10 to 1,000, alternatively from 10 to 500, alternatively from 10 to 250, alternatively from 10 to 100, alternatively from 20 to 80, alternatively from 30 to 60. When (B) organopolysiloxane is substantially linear, the value of subscript z may be referred to as the degree of polymerization (DP) of the (B) organopolysiloxane.

[0090] When the (B) organopolysiloxane is substantially linear, alternatively linear, the at least two mercapto groups may be located at pendant positions, terminal positions, or both pendant and terminal positions.

[0091] In one embodiment, when the (B) organopolysiloxane is substantially linear and has pendant mercapto groups, the subscript o is 0 and the (B) organopolysiloxane has the following average unit formula:

[0092] (R 4 3 SiO 1 / 2 ) 2 (R 4 R 6 SiO 2 / 2 ) z’ (R 4 2 SiO 2 / 2 ) z” ,

[0093] wherein z' is an integer from 2 to 100, and subscript z" is an integer from 8 to 9998, provided that 10≤z'+z"≤10000. Typically, z' is 2 to 80, alternatively 2 to 60, alternatively 2 to 40, alternatively 2 to 20, alternatively 2 to 10, and z" is 8 to 9000, alternatively 8 to 7000, alternatively 8 to 5000, alternatively 8 to 3000, alternatively 8 to 1000, alternatively 10 to 500, alternatively 10 to 100. For example, as a specific example of the (A) organopolysiloxane having a mercapto group in a side chain, the (B) organopolysiloxane may have the following average formula:

[0094] [(CH 3 ) 3 SiO 1 / 2 ] 2 [(CH 3 )R 6 SiO 2 / 2 ] z’ [(CH 3 ) 2 SiO 2 / 2 ] z” .

[0095] With respect to this average formula, any methyl group may be replaced with a different monovalent hydrocarbon group such as an alkyl or aryl group.

[0096] Alternatively, as a specific example of the (B) organopolysiloxane having an average of at least two mercapto groups at terminal positions per molecule, the (B) organopolysiloxane may have the following average formula: 6 (CH 3 ) 2 SiO[(CH 3 ) 2 SiO] z Si(CH 3 ) 2 R 6 , where the subscripts z and R 6 As defined above. With respect to this average formula, any methyl group may be replaced by a different monovalent hydrocarbon group.

[0097] Since the at least two mercapto groups may be both pendant and terminal, the (B) organopolysiloxane may alternatively have the following average unit formula:

[0098] [R 6 (CH 3 ) 2 SiO 1 / 2 ] 2 [(CH 3 )R 6 SiO 2 / 2 ] z’ [(CH 3 ) 2 SiO 2 / 2 ] z” or

[0099] [R 6 (CH 3 ) 2 SiO 1 / 2 ][(CH 3 ) 3 SiO 1 / 2 ][(CH 3 )R 6 SiO 2 / 2 ] z’ [(CH 3 ) 2 SiO 2 / 2 ] z” .

[0100] When the (B) organopolysiloxane is a substantially linear polyorganopolysiloxane, examples of the (B) organopolysiloxane may include: dimethylpolysiloxane terminated with dimethylmercaptosiloxy groups at both molecular ends; methylphenylpolysiloxane terminated with dimethylmercaptosiloxy groups at both molecular ends; a copolymer of methylphenylsiloxane and dimethylsiloxane terminated with dimethylmercaptosiloxy groups at both molecular ends; a copolymer of methylmercaptosiloxane and methylphenylsiloxane terminated with dimethylmercaptosiloxy groups at both molecular ends; a copolymer of methylmercaptosiloxane and diphenylsiloxane terminated with dimethylmercaptosiloxy groups at both molecular ends; copolymers of methylmercaptosiloxane, methylphenylsiloxane and dimethylsiloxane terminated with dimethylmercaptosiloxy groups at both ends of the molecule; copolymers of methylmercaptosiloxane and methylphenylsiloxane terminated with trimethylsiloxy groups at both ends of the molecule; copolymers of methylmercaptosiloxane and diphenylsiloxane terminated with trimethylsiloxy groups at both ends of the molecule; copolymers of dimethylsiloxane and methylmercaptosiloxane terminated with trimethylsiloxy groups at both ends of the molecule; and copolymers of methylmercaptosiloxane, methylphenylsiloxane and dimethylsiloxane terminated with trimethylsiloxy groups at both ends of the molecule.

[0101] Alternatively, (B) the organopolysiloxane may comprise a substantially linear, alternatively linear, polyorganosiloxane selected from the group consisting of:

[0102] i) dimethylmercaptosiloxy-terminated polydimethylsiloxane,

[0103] ii) dimethylmercaptosiloxy-terminated poly(dimethylsiloxane / methylmercaptosiloxane),

[0104] iii) dimethylmercaptosiloxy-terminated polymethylmercaptosiloxane,

[0105] iv) trimethylsiloxy-terminated poly(dimethylsiloxane / methylmercaptosiloxane),

[0106] v) trimethylsiloxy-terminated polymethylmercaptosiloxane,

[0107] vi) dimethylmercaptosiloxy-terminated poly(dimethylsiloxane / methylmercaptosiloxane),

[0108] vii) dimethylmercaptosiloxy-terminated poly(dimethylsiloxane / methylphenylsiloxane),

[0109] viii) dimethylmercaptosiloxy-terminated poly(dimethylsiloxane / diphenylsiloxane),

[0110] ix) phenyl, methyl, mercapto-siloxy terminated polydimethylsiloxane, and

[0111] x) their combination.

[0112] The (B) organopolysiloxane may include a combination of two or more different polyorganosiloxanes that differ in at least one characteristic such as structure, molecular weight, degree of polymerization, content of monovalent groups bonded to silicon atoms, and aliphatic unsaturated groups.

[0113] In some embodiments, the (B) organopolysiloxane is present in the composition in an amount of 0.5 wt % to 40 wt %, alternatively 0.5 wt % to 30 wt %, alternatively 0.5 wt % to 20 wt %, alternatively 1 wt % to 15 wt %, alternatively 5 wt % to 15 wt %, alternatively 7 wt % to 12 wt %, based on the total weight of the composition.

[0114] In these or other embodiments, the content of component (B) is selected so that the weight ratio of (A) organopolysiloxane to (B) organopolysiloxane is 100:1 to 1:100, alternatively 50:1 to 1:50, alternatively 25:1 to 1:25, alternatively 15:1 to 1:15, alternatively 15:1 to 1:1, alternatively 12:1 to 3:1 (wt / wt (A):(B)).

[0115] The composition also includes (C) a photoinitiator. The (C) photoinitiator is selected to enhance the curing of the composition when exposed to radiation. The (C) photoinitiator can be selected from any known free radical type photoinitiator that effectively promotes a crosslinking reaction between a thiol (or thiol) and an aliphatic unsaturated group. This crosslinking is generally referred to as "thiol-ene" curing. Examples of component (C) include diethoxyacetophenone (DEAP), benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, diethoxyflavone, chloro-thioxanthone, azo-bisisobutyronitrile, N-methyldiethanolamine benzophenone, 4,4'-bis(dimethylamino)benzophenone, diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1- Phenylpropan-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, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and combinations thereof. In a specific embodiment, (C) the photoinitiator includes, alternatively, 2-hydroxy-2-methylpropiophenone.

[0116] (C) The photoinitiator is present in the composition in a catalytically effective amount to cure the composition, which amount can be readily determined by one skilled in the art. In some embodiments, the (C) photoinitiator is present in the composition in an amount of 0.001 wt % to 20 wt %, alternatively 0.01 wt % to 10 wt %, alternatively 0.01 wt % to 8 wt %, alternatively 0.01 wt % to 5 wt %, alternatively 0.1 wt % to 3 wt %, alternatively 0.5 wt % to 1.5 wt %, alternatively 0.9 wt % to 1 wt %, based on the total weight of the composition.

[0117] The composition further comprises (D) an acryloxy-functional silane. The acryloxy-functional silane of component (D) is represented by the following formula:

[0118]

[0119] Where X is a divalent hydrocarbon group, each R is independently a hydrocarbon group, and each R 1 is independently an alkyl group having 1 to 8 carbon atoms, the subscript x is 2 or 3, and R 2 H or R 1 .

[0120] In a specific embodiment, X can be written as -(CH 2 ) t -, wherein subscript t is 1 to 10, alternatively 1 to 9, alternatively 1 to 8, alternatively 1 to 7, alternatively 2 to 6. Examples of the divalent hydrocarbon group X when subscript t is 1 to 8 include alkylene groups having 1 to 8 carbon atoms, such as a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, and an octylene group.

[0121] Suitable hydrocarbon groups for R are as described above for R 4 Each R 1 is independently an alkyl group having 1 to 8, alternatively 1 to 7, alternatively 1 to 6, alternatively 1 to 5, alternatively 1 to 4, alternatively 1 to 3, alternatively 1 to 2, alternatively 1 carbon atom. In addition, because each R 1 are independent, component (D) may independently contain different silicon-bonded alkoxy groups, i.e., component (D) may contain trimethoxysilyl moieties, trimethoxyethoxysilyl moieties, methoxydiethoxysilyl moieties, triethoxysilyl moieties, trimethoxyethoxypropoxysilyl moieties, etc. In one embodiment, each R 1 are the same.

[0122] R 2 H or R 1 When R 2When R is H, component (D) includes acrylate functional groups. 2 When methyl, component (D) includes methacrylate functional groups.

[0123] The subscript x is 2 or 3. When the subscript x is 2, component (D) has the following formula:

[0124]

[0125] When the subscript x is 3, component (D) has the following formula:

[0126]

[0127] In a specific embodiment, R 2 is methyl, X is propylene, the subscript x is 3, and each R 1 is methyl, so that component (D) comprises, alternatively consists essentially of, or alternatively consists of 3-methacryloxypropyltrimethoxysilane. Other specific examples of component (D) include acryloxypropyltrimethoxysilane, acryloxypropyldimethoxymethylsilane, methacryloxybutyltrimethoxysilane, methacryloxypropyltriethoxysilane, methacryloxypropyldiethoxyethylsilane, methacryloxypropyldimethoxyethoxysilane, acryloxybutyltriethoxysilane, and the like.

[0128] The (D) acryloxy-functional silane is present in the composition in an amount from greater than 0 wt % to 10 wt %, alternatively from 0.01 wt % to 10 wt %, alternatively from 0.01 wt % to 7 wt %, alternatively from 0.05 wt % to 5 wt %, alternatively from 0.1 wt % to 3 wt %, alternatively from 0.1 wt % to 2 wt %, based on the total weight of the composition.

[0129] The composition further comprises (E) a compound of the formula Si(OR 3 ) 4 A tetraorthosilicate represented by 3 is independently an alkyl group having 1 to 10 carbon atoms.

[0130] Each R 3 is independently an alkyl group having 1 to 10, alternatively 1 to 9, alternatively 1 to 8, alternatively 1 to 7, alternatively 1 to 6, alternatively 1 to 5, alternatively 1 to 4, alternatively 1 to 3, alternatively 1 or 2, alternatively 1 carbon atom. In addition, because each R 3 are independent, component (E) may include different silicon-bonded alkoxy groups. In one embodiment, each R 3 are the same.

[0131] In a specific embodiment, the tetraorthosilicate of component (E) includes or alternatively is tetraethyl orthosilicate (TEOS) and / or tetrapropyl orthosilicate (TPOS). Other examples of tetraorthosilicates suitable for component (E) include dimethoxydiethoxysilane, trimethoxyethoxysilane, tetramethoxysilane, tetrabutoxysilane, methoxydiethoxybutoxysilane, dipropoxydibutoxysilane, and the like.

[0132] The (E) tetraorthosilicate is present in the composition in an amount of 0.01 wt % to 20 wt %, alternatively 0.01 wt % to 10 wt %, alternatively 0.01 wt % to 7.5 wt %, alternatively 0.5 wt % to 5 wt %, alternatively 0.1 wt % to 3 wt %, alternatively 0.5 wt % to 2.5 wt %, based on the total weight of the composition.

[0133] The total molar ratio of the mercapto groups of component (B) to the silicon-bonded aliphatic unsaturated groups in components (A) and (D) will vary based on the selection of (A) organopolysiloxane, (B) organopolysiloxane, and (D) acryloxy-functional silane in the composition. In certain embodiments, the total molar ratio of the mercapto groups of component (B) to the silicon-bonded aliphatic unsaturated groups in components (A) and (D) is from 10:1 to 1:10, alternatively from 0.1:1 to 5:1, alternatively from 0.1:1 to 3:1, alternatively from 0.3:1 to 2:1 (mercapto groups of (B) to silicon-bonded aliphatic unsaturated groups of (A) and (D)).

[0134] The composition may further comprise (F) a filler. The (F) filler is not limited and may be, for example, a reinforcing filler, a compatibilizing filler, a thermally conductive filler, an electrically conductive filler, a flame retardant filler, a thermally stable filler, an acid accepting filler, a rheology modifying filler, a phosphor, a coloring filler, a mineral filler, a glass filler, a carbon filler, or a combination thereof. The choice of the (F) filler is generally a function of the cured product to be formed with the composition and the end-use application of the cured product.

[0135] The (F) filler may be untreated, pretreated, or added with an optional filler treating agent described below, which when so added may treat the (F) filler in situ or prior to incorporating the (F) filler into the composition. The (F) filler may be a single filler or a combination of two or more fillers differing in at least one characteristic, such as filler type, method of preparation, treatment or surface chemistry, filler composition, filler shape, filler surface area, average particle size, or particle size distribution.

[0136] The shape and size of the (F) filler and / or (I) pigment are also not particularly limited. For example, the (F) filler can be spherical, rectangular, oval, irregular, and can be in the form of, for example, powder, flour, fiber, flakes, fragments, shavings, strands, scrims, wafers, wool, straw, particles, and combinations thereof. The size and shape are typically selected based on the type of (F) filler utilized, the selection of other components included in the composition, and the end-use application of the cured product formed therewith.

[0137] Non-limiting examples of fillers that can be used as reinforcing fillers include reinforcing silica fillers, such as fumed silica, silica aerogels, silica xerogels, and precipitated silica. Fumed silica is known in the art and is commercially available; for example, fumed silica sold under the trade name CAB-O-SIL by Cabot Corporation of Massachusetts, USA.

[0138] Non-limiting examples of fillers that can be used as expanding or reinforcing fillers include quartz and / or crushed quartz, alumina, magnesium oxide, silica (e.g., pyrogenic, ground, precipitated silica), hydrated magnesium silicate, magnesium carbonate, dolomite, silicone resins, wollastonite, saponite, kaolin, china clay, muscovite, phlogopite, halloysite (hydrated aluminum silicate), aluminum silicate, sodium aluminosilicate, glass (fibers, beads or particles, including recycled glass, e.g., from wind turbines or other sources), clay, magnetite, hematite, calcium carbonate (such as precipitated , pyrogenic and / or ground calcium carbonate), calcium sulfate, barium sulfate, calcium metasilicate, zinc oxide, talc, diatomaceous earth, iron oxide, clay, mica, chalk, titanium dioxide, zirconium oxide, sand, carbon black, graphite, anthracite, coal, lignite, charcoal, activated carbon, non-functionalized silicone resins, aluminum oxide, silver, metal powders, magnesium oxide, magnesium hydroxide, magnesium oxysulfate fibers, aluminum trihydrate, aluminum hydroxide, coated fillers, carbon fibers (including recycled carbon fibers, e.g. from the aircraft and / or automotive industries), aromatic polyamides (such as chopped KEVLAR TM or Twaron TM), nylon fibers, mineral fillers or pigments (e.g., titanium dioxide, non-hydrated, partially hydrated or hydrated fluorides, chlorides, bromides, iodides, chromates, carbonates, hydroxides, phosphates, hydrogen phosphates, nitrates, oxides and sulfates of sodium, potassium, magnesium, calcium and barium; zinc oxide, antimony pentoxide, antimony trioxide, beryllium oxide, chromium oxide, cerium oxide, lithopone, boric acid or borates (such as zinc borate, barium metaborate or aluminum borate), mixed metal oxides (such as vermiculite, bentonite, pumice, perlite, fly ash, clay and silica gel); rice husk ash, ceramics and zeolites, metals (such as aluminum flakes or powders, bronze powders, copper, gold, molybdenum, nickel, silver powders or flakes), stainless steel powders, tungsten, barium titanate, silica-carbon black composites, functionalized carbon nanotubes, cement, slate powder, pyrophyllite, sepiolite, zinc stannate, zinc sulfide) and combinations thereof. Alternatively, the expanding or reinforcing filler may be selected from the group consisting of calcium carbonate, talc, and combinations thereof.

[0139] As is known in the art, certain fillers can be used as pigments. For example, white pigments can include metal oxides such as titanium oxide, aluminum oxide, zinc oxide, zirconium oxide, magnesium oxide, etc.; hollow fillers such as glass spheres, glass beads, etc.; and additionally, barium sulfate, zinc sulfate, barium titanate, aluminum nitride, boron nitride, and antimony oxide. Such components can be considered fillers and / or pigments.

[0140] Extending fillers are known in the art and are commercially available; for example, ground silica sold under the trade name MIN-U-SIL by US Silica of Berkeley Springs, WV. Suitable precipitated calcium carbonates include Winnofil from Solvay. TM SPM and Ultra-pflex from Silicon Motion Technology (SMI) TM and Ultra-pflex TM 100.

[0141] When (F) filler includes a thermally conductive filler, (F) filler can be both thermally conductive and electrically conductive. Alternatively, (F) filler can be thermally conductive and electrically insulating. The thermally conductive filler can also have other beneficial properties, such as but not limited to reinforcing filler, volume-increasing filler, or another property as described above. The thermally conductive filler can be selected from but not limited to the group consisting of: aluminum nitride, aluminum oxide, aluminum trihydrate, hydrous aluminum oxide, barium titanate, barium sulfate, beryllium oxide, carbon fiber, diamond, graphite, magnesium hydroxide, magnesium oxide, basic magnesium sulfate fiber, metal particles, onyx, silicon carbide, tungsten carbide, zinc oxide, coated fillers and combinations thereof.

[0142] When (F) the filler includes a thermally conductive filler, the thermally conductive filler may include a metal filler, an inorganic filler, a fusible filler, or a combination thereof. Metal fillers include metal particles, metal powders, and metal particles having a layer on the surface of the particles. These layers may be, for example, metal nitride layers or metal oxide layers. Examples of suitable metal fillers include particles of metals selected from the group consisting of aluminum, copper, gold, nickel, silver, and combinations thereof, and alternatively aluminum. Examples of suitable metal fillers also include particles of the metals listed above having layers on their surfaces, which are selected from the group consisting of aluminum nitride, aluminum oxide, copper oxide, nickel oxide, silver oxide, and combinations thereof. For example, the metal filler may include aluminum particles having an aluminum oxide layer on their surfaces. Examples of inorganic fillers include onyx; aluminum trihydrate, aluminum hydroxide, metal oxides (such as aluminum oxide, beryllium oxide, magnesium oxide, and zinc oxide); nitrides (such as aluminum nitride); carbides (such as silicon carbide and tungsten carbide); and combinations thereof. Alternatively, examples of inorganic fillers include aluminum oxide, zinc oxide, and combinations thereof. The fusible filler may include Bi, Ga, In, Sn or their alloys. The fusible filler may optionally further include Ag, Au, Cd, Cu, Pb, Sb, Zn or a combination thereof. Examples of suitable fusible fillers include Ga, In-Bi-Sn alloys, Sn-In-Zn alloys, Sn-In-Ag alloys, Sn-Ag-Bi alloys, Sn-Bi-Cu-Ag alloys, Sn-Ag-Cu-Sb alloys, Sn-Ag-Cu alloys, Sn-Ag alloys, Sn-Ag-Cu-Zn alloys and combinations thereof. The melting point of the fusible filler may be 50° C. to 250° C. The fusible filler may be a eutectic alloy, a non-eutectic alloy or a pure metal. Many suitable fusible fillers are commercially available.

[0143] Alternatively or in addition, the (F) filler may include a non-reactive silicone resin. For example, the (F) filler may include a T resin, a TD resin, a TDM resin, a TDMQ resin, an MQ resin, or any other non-reactive silicone resin. Typically, such non-reactive silicone resins include at least 30 mol % of T siloxy and / or Q siloxy units. As is known in the art, the D siloxy units are composed of R 0 2 SiO 2 / 2 Represented by, and T siloxy unit is composed of R 0 SiO 3 / 2 Indicates that R 0 are independently selected substituents.

[0144] Weight average molecular weight M of non-reactive silicone resin w The molecular weight of the silicone resin will depend at least in part on the type of substituents (e.g., hydrocarbon groups) present in the non-reactive silicone resin. wrepresents the weight average molecular weight measured using conventional gel permeation chromatography (GPC), calibrated using narrow molecular weight distribution polystyrene (PS) standards when the peak representing the neopentamer is excluded from the measurement. PS equivalent weight M of non-reactive silicone resin w It can be 12000 g / mole to 30000 g / mole, typically 17000 g / mole to 22000 g / mole. The non-reactive silicone resin can be prepared by any suitable method. This type of silicone resin has been prepared by co-hydrolysis of the corresponding silane or by a silica hydrosol end-capping method generally known in the art.

[0145] Phosphor is a filler of this type, which can convert the emission wavelength from a light source (optical semiconductor device) when the cured product of the composition is used as a wavelength conversion material. Such phosphors are not particularly limited, and examples of phosphors include yellow, red, green and blue phosphors, including oxide phosphors, oxynitride phosphors, nitride phosphors, sulfide phosphors, oxysulfide phosphors, etc., which are widely used in light emitting diodes (LEDs).

[0146] In certain embodiments, (F) filler may include an acid acceptor. The acid acceptor may include a metal oxide, such as magnesium oxide. Acid acceptors are generally known in the art and may be commercially available under trade names including Rhenofit F, Star Mag CX-50, Star MagCX-150, BLP-3, and MaxOx98LR. Rhenofit F is calcium oxide purchased from Rhein Chemie Corporation in Shaden, Ohio, USA. Star Mag CX-50 is magnesium oxide purchased from Merrand International Corp. in Portsmouth, New Hampshire, USA. MagOX98LR is magnesium oxide purchased from Premier Chemicals LLC in West Conshohocken, Pennsylvania, USA. BLP-3 is calcium carbonate purchased from Omya Americas in Cincinnati, Ohio, USA.

[0147] Regardless of the choice of (F) filler, the (F) filler may be untreated, pretreated, or added to form the composition with an optional filler treating agent which, when so added, treats the (F) filler in situ in the composition.

[0148] The filler treating agent may include, for example, silanes (such as alkoxysilanes), alkoxy functional oligosiloxanes, cyclic polyorganosiloxanes, hydroxyl functional oligosiloxanes (such as dimethylsiloxane or methylphenylsiloxane), olefin functional diols, organosilicon compounds, stearates, or fatty acids. The filler treating agent may include a single filler treating agent, or a combination of two or more filler treating agents selected from similar or different types of molecules.

[0149] The filler treatment agent may include an alkoxysilane, which may be a monoalkoxysilane, a dialkoxysilane, a trialkoxysilane, or a tetraalkoxysilane. Examples of alkoxysilane filler treatment agents are: hexyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetradecyltrimethoxysilane, phenyltrimethoxysilane, phenethyltrimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, and combinations thereof. In certain aspects, the alkoxysilane may be used in combination with a silazane, which may catalyze the reaction of a less reactive alkoxysilane with a surface hydroxyl group. Such reactions are typically performed at temperatures above 100°C with high shear forces and with the removal of volatile byproducts such as ammonia, methanol, and water.

[0150] Suitable filler treating agents also include alkoxysilyl functionalized alkylmethyl polysiloxanes, or similar materials in which the hydrolyzable groups may include, for example, silazane, acyloxy, or oxime groups. In one embodiment, the filler treating agent is a silazane, which may be functionalized, for example, with alkenyl groups. One such example is a silazane of the formula ((CH 3 ) 2 ViSi) 2 NH silazane, wherein Vi represents a vinyl group.

[0151] Alkoxy functional oligosiloxanes can also be used as filler treating agents. Alkoxy functional oligosiloxanes and methods for their preparation are well known in the art. Other filler treating agents include mono-terminated alkoxy functional polydiorganosiloxanes, i.e., polyorganosiloxanes having an alkoxy functional group at one end.

[0152] Alternatively, the filler treating agent can be any organosilicon compound commonly used to treat silica fillers. Examples of organosilicon compounds include organochlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane, and trimethylmonochlorosilane; organosiloxanes such as hydroxyl-terminated dimethylsiloxane oligomers, silhydride functionalized siloxanes, hexamethyldisiloxane, and tetramethyldivinyldisiloxane; organosilazanes such as hexamethyldisilazane and hexamethylcyclotrisilazane; and organoalkoxysilanes such as alkylalkoxysilanes having methyl, propyl, n-butyl, isobutyl, n-hexyl, n-octyl, isooctyl, n-decyl, dodecyl, tetradecyl, hexadecyl, or octadecyl substituents. The organic reactive alkoxysilane may include amino, methacryloxy, vinyl, glycidoxy, epoxycyclohexyl, isocyanurate, isocyanate, mercapto, thio, vinyl-benzyl-amino, benzyl-amino, or phenyl-amino substituents. Alternatively, the filler treatment agent may include an organopolysiloxane. Using such a filler treatment agent to treat the surface of the (F) filler can utilize multiple hydrogen bonds (clustered or dispersed or both) as a method for bonding the organosiloxane to the surface of the (F) filler. The organosiloxane capable of hydrogen bonding has an average of at least one silicon-bonded group capable of hydrogen bonding per molecule. The group may be selected from: a monovalent organic group having multiple hydroxyl functional groups or a monovalent organic group having at least one amino functional group. Hydrogen bonding can be the main mode of bonding of the organosiloxane to the (F) filler. The organosiloxane may not be able to form a covalent bond with the (F) filler. The organosiloxane capable of hydrogen bonding can be selected from the group consisting of: a sugar-siloxane polymer, an amino-functionalized organosiloxane, and a combination thereof. Alternatively, the polyorganosiloxane capable of hydrogen bonding can be a sugar-siloxane polymer.

[0153] Alternatively, the filler treating agent may include alkyl mercaptans (such as octadecyl mercaptan, etc.) and fatty acids (such as oleic acid, stearic acid), titanates, titanate coupling agents, zirconate coupling agents, and combinations thereof. Those skilled in the art can optimize the filler treating agent to help (F) filler dispersion without undue experimentation.

[0154] If used, the relative amounts of filler treating agent and (F) filler are selected based on the specific filler used as well as the filler treating agent and their desired effects or properties.

[0155] In some embodiments, the (F) filler is present in the composition in an amount of 1 wt % to 70 wt %, alternatively 5 wt % to 60 wt %, alternatively 10 wt % to 50 wt %, alternatively 10 wt % to 35 wt %, alternatively 20 wt % to 30 wt %, alternatively 25 wt % to 27 wt %, based on the total weight of the composition.

[0156] In certain embodiments, the composition further comprises (G) a condensation catalyst. In general, when using an adhesion promoter containing hydrolyzable and / or condensable groups, it is not necessary to use a condensation catalyst. These groups can be hydrolyzed with moisture (e.g., relative humidity) in the environment, and react with hydroxyl groups present on the surface of certain substrates. However, without being limited by theory, it is believed that the incorporation of (G) a condensation catalyst allows the composition to be dual-cured, such that the composition can be cured via condensation and exposure to irradiation. For example, the thiol group of component (B) can be bonded to the acryloxy functional group of component (D), so that condensation curing and thiol-ene curing can occur simultaneously. Dual curing is particularly advantageous in some end uses of the composition, because condensation curing can promote better curing in areas that are difficult to irradiate, such as if there is a shadow due to the surface characteristics on the substrate on which the composition is cured.

[0157] The condensation catalyst (G) is not limited, and in some embodiments, examples of the condensation catalyst are tin catalysts, titanium catalysts, zirconate catalysts, and zirconium catalysts. General examples of suitable tin catalysts include organic tin compounds, wherein the valence of tin is +4 or +2 (e.g., tin (IV) compounds and / or tin (II) compounds). Specific examples of tin (IV) compounds include orthotin salts of carboxylic acids such as dibutyltin dilaurate, dimethyltin dilaurate, di(n-butyl) diketone tin, dibutyltin diacetate, dibutyltin maleate, dibutyltin diacetylacetonate, dibutyltin dimethoxide, trisuccinoic acid methoxyphenyltin, dibutyltin dioctoate, dibutyltin diformate, isobutyltin triceroate, dimethyltin dibutyrate, dimethyltin dineodecanoate, dibutyltin dineodecanoate, triethyltin tartrate, dibutyltin dibenzoate, butyltin tri-2-ethylhexanoate, dioctyltin diacetate, tin octoate, tin oleate, tin butyrate, tin naphthenate, dimethyltin dichloride, combinations thereof, and / or partial hydrolyzates thereof. Specific examples of tin (II) compounds include: tin (II) salts of organic carboxylic acids, such as tin (II) diacetate, tin (II) dioctoate, tin (II) diethylhexanoate, tin (II) dilaurate; stannous salts of carboxylic acids, such as stannous octoate, stannous oleate, stannous acetate, stannous laurate, stannous stearate, stannous naphthoate, stannous hexanoate, stannous succinate, stannous octoate, and combinations thereof. Examples of suitable titanium catalysts include: titanium esters, such as tetra-n-butyl titanate, tetraisopropyl titanate, tetra-2-ethylhexyl titanate, tetraphenyl titanate, triethanolamine titanate, organosiloxy titanium compounds; and dicarbonyl titanium compounds, such as ethyl acetoacetate titanium, diisopropyl di(ethoxyacetoacetyl) titanium, and bis(acetylacetonato)-diisopropoxytitanium (IV). In a specific embodiment, (G) the condensation catalyst is an ethyl acetoacetate titanium complex mixed with methyltrimethoxysilane.

[0158] In certain embodiments, (G) a condensation catalyst is used. In specific embodiments, the (G) condensation catalyst is present in the composition in an amount of 0.001 wt % to 5 wt %, alternatively 0.01 wt % to 3 wt %, alternatively 0.01 wt % to 1 wt %, alternatively 0.01 wt % to 0.5 wt %, alternatively 0.01 wt % to 0.2 wt %, based on the total weight of the composition.

[0159] In certain embodiments, the composition is solvent-free, i.e., the composition does not contain an organic solvent. Examples of organic solvents include those comprising alcohols such as methanol, ethanol, isopropanol, butanol, or n-propanol; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as heptane, hexane, and octane; glycol ethers such as propylene glycol methyl ether, dipropylene glycol methyl ether, propylene glycol n-butyl ether, propylene glycol n-propyl ether, and ethylene glycol n-butyl ether; halogenated hydrocarbons such as dichloromethane, 1,1,1-trichloroethane, and dichloromethane; chloroform; dimethyl sulfoxide; dimethylformamide, acetonitrile; tetrahydrofuran; white spirit; solvent oil; naphtha; N-methylpyrrolidone; etc., and derivatives, modifications, and combinations thereof.

[0160] In some embodiments, the composition further comprises one or more additives. Examples of suitable additives that may be present in the composition include fillers, treatment agents (e.g., filler treatment agents), crosslinking agents, adhesion promoters, surface modifiers, desiccants, compatibilizers, biocides, flame retardants, plasticizers, end-capping agents, binders, anti-aging additives, water release agents, pigments, dyes, rheology modifiers, carriers, tackifiers, corrosion inhibitors, catalyst inhibitors, viscosity modifiers, UV absorbers, antioxidants, light stabilizers, etc., and combinations thereof. In a specific embodiment, the composition does not contain organopolysiloxanes, siloxanes, and silanes other than components (A)-(E).

[0161] As described above, a method for forming a cured product ("the method") is disclosed. The method includes the step of applying a composition onto a substrate surface. The method also includes the step of irradiating the composition on the substrate to obtain a cured product. When the composition includes (G) a condensation catalyst, the method may also include moisture curing the composition. However, moisture curing generally begins upon exposure to atmospheric moisture, and no active step is required to initiate moisture curing.

[0162] The composition can be applied to the substrate in any suitable manner (i.e., arranged or distributed). Typically, the composition is applied in wet form by a wet coating technique. The composition can be applied by i) spin coating; ii) brush coating; iii) drip coating; iv) spray coating; v) dip coating; vi) roller coating; vii) flow coating; viii) slot coating; ix) concave coating; x) Mayer rod coating; or xi) any combination of two or more of i) to x). Typically, the composition is arranged on the substrate resulting in a wet deposit or uncured layer on the substrate, which is then cured to obtain a cured product on the substrate.

[0163] The substrate is not limited and can be any substrate. Depending on its selection, the cured product can be physically and / or chemically bonded to the substrate. The substrate can optionally have a continuous or discontinuous shape, size, dimension, surface roughness and other characteristics.

[0164] The substrate can be an electronic article or component. In other embodiments, the substrate can include glass. Alternatively, the substrate can include plastic, which can be thermosetting and / or thermoplastic. However, alternatively, the substrate can be or include metal, ceramic, glass fiber, cellulose (e.g., paper), wood, cardboard, paperboard, silicone or polymer material or a combination thereof.

[0165] Specific examples of suitable substrates include paper stock such as kraft paper, polyethylene coated kraft paper (PEK coated paper), thermal paper and conventional paper; polymer substrates such as polyamide (PA); polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN) and liquid crystal polyesters; polyolefins such as polyethylene (PE), polypropylene (PP) and polybutylene; styrene resins; polyoxymethylene (POM); polycarbonate (PC); polymethyl methacrylate (PMMA); polyvinyl chloride (PVC); polyphenylene sulfide (PPS); poly Phenyl ether (PPE); polyimide (PI); polyamide-imide (PAI); polyetherimide (PEI); polysulfone (PSU); polyethersulfone; polyketone (PK); polyetherketone; polyvinyl alcohol (PVA); polyetheretherketone (PEEK); polyetherketoneketone (PEKK); polyarylate (PAR); polyethernitrile (PEN); phenolic resin; phenoxy resin; cellulose, such as triacetyl cellulose, diacetyl cellulose and cellophane; fluorinated resins, such as polytetrafluoroethylene; thermoplastic elastomers, such as polystyrene type, polyolefin type, polyurethane type, polyester type, polyamide type, polybutadiene type, polyisoprene type and fluorine type; and copolymers and combinations thereof.

[0166] The wet deposit or uncured layer is cured by exposure to radiation (usually UV radiation). Useful UV radiation sources include conventional mercury vapor lamps (which are designed to emit UV energy in various UV bands), LED curing lamps, and the like. For example, useful radiation wavelengths range from 200 nm to 400 nm. UV curing is typically performed at 40 mW / cm 2 (“mW / cm 2 ”) to 30000mW / cm 2 In the range of about 70 mW / cm 2 to about 600mW / cm 2 In certain embodiments, the irradiation is performed in an inert atmosphere, such as under nitrogen. In a specific embodiment, UV curing is typically performed at 300 mW / cm 2 Strength and 4J / cm 2 Doses of UVA and UVB are performed.

[0167] If desired, the cured product formed by irradiating the uncured layer can be patterned. For example, in these embodiments, a photomask is typically used in the selective curing of the target portion of the uncured layer. The photomask typically has a defined pattern for transmitting UV radiation and a complementary pattern for blocking UV radiation transmission. For example, the photomask includes a portion that allows UV radiation transmission and a portion that blocks UV radiation transmission, so that the defined pattern can be transferred or copied via selective curing. The portion of the photomask that allows UV radiation transmission is aligned with the target portion of the uncured layer, and the complementary portion of the photomask that blocks UV radiation transmission is aligned with the non-target portion of the uncured layer. Such a method may be referred to as photolithography. The target portion of the uncured layer is cured to provide a cured area, and the non-target portion of the uncured layer is not cured to provide an uncured area.

[0168] The uncured areas of the cured product retained by using a photomask can be etched by a wet method (e.g., with an organic solvent or aqueous alkali), alternatively by a dry method (e.g., with plasma or reactive ions). Typically, the uncured areas are etched or removed with a solvent such as butyl acetate, alcohol, ketone, aromatic hydrocarbon, alkane, ether, ester, and combinations thereof. Etching or removing the uncured areas produces only cured areas, which can have a 100% pattern retention rate.

[0169] When the composition comprises (G) a condensation catalyst and the method further comprises moisture curing of the composition (and / or the cured product formed by irradiation), moisture curing can be carried out without any pre-emptive step. The composition (and / or the cured product formed by irradiation) can be moisture cured before, during or after irradiation curing. In one embodiment, moisture curing is carried out after irradiation curing, specifically by removing an inert atmosphere and exposing the cured product formed by irradiation to moisture (e.g., relative humidity). When irradiating in an inert atmosphere, a sequential curing step is generally used, and the inert atmosphere generally does not include ambient moisture that affects moisture curing.

[0170] In certain embodiments, the cured product may be exposed to a post-bake, for example, exposure to an elevated temperature for a period of time. The elevated temperature is typically 80°C to 140°C, alternatively 100°C to 120°C.

[0171] As described above, a cured product disposed on a substrate is also disclosed. The substrate is not limited and may be any substrate. Depending on its selection, the cured product may be physically and / or chemically bonded to the substrate. The substrate may optionally have a continuous or discontinuous shape, size, dimension, surface roughness, and other characteristics.

[0172] The following examples are intended to illustrate the present invention and should not be viewed in any way as limiting the scope of the present invention.

[0173] Certain components utilized in the examples are listed in Table 1 below.

[0174] Table 1: Components / compounds used

[0175]

[0176] General Procedure 1: Compositions of Examples 1-7 and Comparative Examples 1-5

[0177] Compositions were prepared in Examples 1-7 and Comparative Examples 1-5 according to General Procedure 1. In General Procedure 1, a preliminary organopolysiloxane mixture was formed in a 100 mL tooth cup by placing organopolysiloxane (A-1), organopolysiloxane (A-2), organopolysiloxane (B-1) and fumed silica filler (F-1) therein (in the amounts specified below). The preliminary organopolysiloxane mixture was then blended at 1000 revolutions per minute (rpm) for 20 seconds and then at 2000 rpm for 45 seconds. The photoinitiator (C-1) used and the specific silane (D) and tetraorthosilicate (E) (as shown in Table 2 below) were then added to each preliminary organopolysiloxane mixture to obtain a blend. Each mixture was then mixed at 2000 rpm for 30 seconds. When used (i.e., in Examples 2-7 and Comparative Examples 5), a condensation catalyst (G-1) was added to the blend to obtain a composition, which was then mixed at 2000 rpm for 30 seconds. Each blend or composition was dispensed into three 30 mL syringes, degassed and packaged in aluminum bags. Table 2 below shows the specific silane (D) and tetraorthosilicate (E) used in the compositions of Examples 1-7 and Comparative Examples 1-5. Tables 3 and 4 show the amount of each component used in each composition of Examples 1-7 and Comparative Examples 1-5.

[0178] Table 2: Silanes and tetraorthosilicates used

[0179] Example Silanes and tetraorthosilicates Example 1 (D-1)&(E-1) Example 2 (D-1)&(E-1) Example 3 (D-1)&(E-1) Example 4 (D-1)&(E-1) Example 5 (D-1)&(E-1) Example 6 (D-1)&(E-1) Example 7 (D-1)&(E-2) Comparative Example 1 (D-1) Comparative Example 2 (E-1) Comparative Example 3 (D-3)&(E-1) Comparative Example 4 (D-2)&(E-1) Comparative Example 5 (E-1)

[0180] Table 3: Compositions of Examples 1-7

[0181] Components Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 (A-1)g 29.76 29.76 29.76 29.76 29.76 29.76 29.76 (A-2)g 31.81 31.81 31.81 31.81 31.81 31.81 31.81 (B-1)g 7.19 7.19 11.33 8.85 8.85 8.85 8.85 (C-1)g 0.94 0.94 0.94 0.94 0.94 0.94 0.94 (D-1)g 0.5 0.5 1.36 0.75 0.75 0.75 0.75 (E-1)g 1.4 1.4 1.41 1.41 0.7 2.2 -- (E-2)g -- -- -- -- -- -- 1.4 (F-1)g 26.39 26.39 26.39 26.39 26.39 26.39 26.39 (G-1)g -- 0.1 0.1 0.1 0.1 0.1 0.1

[0182] Table 4: Comparative Examples 1-5

[0183] Components Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 (A-1)g 29.76 29.76 29.76 29.76 29.76 (A-2)g 31.81 31.81 31.81 31.81 31.81 (B-1)g 7.19 5.81 5.81 5.81 5.81 (C-1)g 0.94 0.94 0.94 0.94 0.94 (D-1)g 0.5 -- -- -- -- (D-2)g -- -- -- 0.5 -- (D-3)g -- -- 0.5 -- -- (E-1)g -- 1.4 1.4 1.4 1.41 (F-1)g 26.39 26.39 26.39 26.39 26.39 (G-1)g -- -- -- -- 0.1

[0184] Each composition of Examples 1-7 and Comparative Examples 1-5 was used to prepare a cured product on a substrate. The adhesion properties of each cured product were then analyzed. The following describes the method for preparing the cured product and the related adhesion property test method.

[0185] Adhesion Testing Procedure

[0186] A 2024T3 Alclad aluminum substrate (7.5 cm x 2.5 cm x 1 mm) was cleaned with acetone and isopropanol and air dried. A 1 cm wide polytetrafluoroethylene (PTFE) tape was placed at the bottom of the substrate. The compositions of Examples 1-7 and Comparative Examples 1-5 were then each cast onto the substrate to obtain a wet deposit having a thickness of 2.5 ± 0.2 mm and a width of 5 ± 1 mm. Each wet deposit was exposed to irradiation (via a Colight UV device with a mercury lamp at 300 mW / cm 2 Strength and 4J / cm 2 The wet deposits were cured by irradiation at room temperature (22° C.) and 35-42% relative humidity (RH). After exposure to irradiation, each wet deposit was further cured for 48 hours at room temperature to obtain a cured product disposed on a substrate.

[0187] Then test the adhesion of each cured product by peeling off the cured product from the PTFE band covering side of substrate.If cured product is peeled off from substrate and does not leave any residue, then think that this cured product has adhesion failure (AF).If cured product sticks on substrate when peeling off and tearing, leaves residue on substrate, then think that sample has cohesive failure (CF).Surprisingly, all cured products formed by the composition of embodiment 1-7 show cohesive failure, and all cured products formed by the composition of comparative example 1-5 show adhesion failure.For the cured product that substrate is had to expect adhesion, expect is cohesive failure rather than adhesion failure.Therefore, confirm that the composition of embodiment 1-7 forms the cured product that substrate has excellent adhesion, particularly compared with the cured product formed by the composition of comparative example 1-5.

[0188] It is to be understood that the appended claims are not limited to individual and particular compounds, compositions, or methods described in the detailed description, which may vary between particular embodiments falling within the scope of the appended claims.

Claims

1. A curable composition, comprising: (A) an organopolysiloxane having an average of at least two silicon-bonded aliphatically unsaturated groups per molecule; (B) an organopolysiloxane containing no aliphatic unsaturated groups and having an average of at least two mercapto groups per molecule; (C) a photoinitiator; (D) an acryloxy-functional silane represented by the formula: Where X is a divalent hydrocarbon group, each R is independently a hydrocarbon group, and each R 1 is independently an alkyl group having 1 to 8 carbon atoms, the subscript x is 2 or 3, and R 2 H or R 1 ;and (E) a tetraorthosilicate of the formula: Si(OR 3 )4, where each R 3 is independently an alkyl group having 1 to 10 carbon atoms.

2. The composition according to claim 1, wherein the composition further comprises (F) a filler; or (G) a condensation catalyst; or both.

3. The composition according to claim 1 or 2, wherein: The (A) organopolysiloxane is present in an amount of 5 wt % to 95 wt %; The (C) photoinitiator is present in an amount of 0.01 wt % to 10 wt %; The (D) acryloxy-functional silane is present in an amount of 0.05 wt % to 5 wt %; and The (E) tetraorthosilicate is present in an amount of 0.05 wt % to 5 wt %; Each of the above is based on the total weight of the composition.

4. The composition of any one of claims 1 to 3, wherein the total molar ratio of the mercapto groups of component (B) to the silicon-bonded aliphatic unsaturated groups in components (A) and (D) is from 0.1:1 to 3:

1.

5. The composition according to any one of claims 1 to 4, wherein the (A) organopolysiloxane is represented by the following average formula: (R 4 3-m R 5 m SiO 1 / 2 ) a (R 4 2-n R 5 n SiO 2 / 2 ) b (R 5 SiO 3 / 2 ) c (SiO 4 / 2 ) d (ZO 1 / 2 ) e , Each R 4 is an independently selected substituted or unsubstituted hydrocarbon group having no aliphatic unsaturation; each R 5 Independently for R 4 or an aliphatic unsaturated group having 1 to 10 carbon atoms; each subscript m is independently an integer from 0 to 3 in each unit indicated by subscript a; each subscript n is an integer from 0 to 2 in each unit indicated by subscript b; provided that at least two R 5 is an aliphatic unsaturated group; each Z is independently H or an alkyl group; and wherein a, b, c, d and e are mole fractions satisfying the following conditions: a>0; b>0; c≥0; d≥0; 0≤e≤0.05; and a+b+c+d+e=1.

6. The composition according to claim 5, wherein c>0 and / or d>0, so that the (A) organopolysiloxane is branched or resinous.

7. The composition according to any one of claims 1 to 4, wherein the (A) organopolysiloxane is represented by the following average formula: (R 4 3-m R 5 m SiO 1 / 2 )2(R 4 2-n R 5 n SiO 2 / 2 ) y ; Wherein y is an integer from 10 to 10000; each R 4 is an independently selected substituted or unsubstituted hydrocarbon group having no aliphatic unsaturation; each R 5 Independently for R 4 or an aliphatic unsaturated group having 1 to 10 carbon atoms; each subscript m is independently an integer from 0 to 3; each subscript n is an integer from 0 to 2 in each unit indicated by subscript y; provided that at least two R 5 It is an aliphatic unsaturated group.

8. The composition according to claim 7, wherein each subscript m is 1 and each subscript n is 0, such that the (A) organopolysiloxane is represented by the following average formula: (R 4 2R 5 SiO 1 / 2 )2(R 4 2SiO 2 / 2 ) y 。 9. The composition according to any one of claims 1-4 and 7-8, wherein the (A) organopolysiloxane comprises: (A1) a first linear organopolysiloxane having a degree of polymerization of 550 to 2000; and (A2) a second organopolysiloxane having a degree of polymerization of 50 to 500.

10. The composition according to any one of claims 1 to 9, wherein the (B) organopolysiloxane is represented by the following average formula: (R 4 3-o R 6 o SiO 1 / 2 ) f (R 4 2-p R 6 p SiO 2 / 2 ) g (R 6 SiO 3 / 2 ) h (SiO 4 / 2 ) i (ZO 1 / 2 ) j , where each R 4 is an independently selected substituted or unsubstituted hydrocarbon group having no aliphatic unsaturation; each R 6 Independently for R 4 or contains a thiol group; each subscript o is independently an integer from 0 to 3 in each unit indicated by subscript f; each p is independently an integer from 0 to 2 in each unit indicated by subscript g; provided that at least two R 6 Independently contains a thiol group; each Z is independently H or an alkyl group; wherein f, g, h, i and j are molar fractions that satisfy the following conditions: f>0; g>0; h≥0; i≥0; 0≤j≤0.05 and f+g+h+i+j=1.

11. The composition according to claim 10, wherein h>0 and / or i>0, so that the (B) organopolysiloxane is branched or resinous.

12. The composition according to any one of claims 1 to 9, wherein the (B) organopolysiloxane is represented by the following average formula: (R 4 3-o R 6 o SiO 1 / 2 )2(R 4 2-p R 6 p SiO 2 / 2 ) z , Where z is an integer from 10 to 10000; each R 4 is an independently selected substituted or unsubstituted hydrocarbon group having no aliphatic unsaturation; each R 6 Independently for R 4 or contains a thiol group; each subscript o is independently an integer from 0 to 3; each p is independently an integer from 0 to 2 in each unit indicated by the subscript z; provided that at least two R 6 Independently comprises a thiol group.

13. The composition according to claim 12, wherein subscript o is 0, and the (B) organopolysiloxane is represented by the following average formula: (R 4 3SiO 1 / 2 )2(R 4 R 6 SiO 2 / 2 ) z’ (R 4 2SiO 2 / 2 ) z” , Wherein z' is an integer from 2 to 100, and the subscript z" is an integer from 8 to 9998, provided that 10≤z'+z"≤10000.

14. A composition according to any one of claims 1 to 13, wherein: (i) the (e) tetraorthosilicate comprises tetraethyl orthosilicate (TEOS) and / or tetrapropyl orthosilicate (TPOS); or (ii) the (D) acryloxy-functional silane comprises 3-methacryloxypropyltrimethoxysilane; or (iii) both (i) and (ii).

15. A method for forming a cured product, the method comprising: Applying the composition according to any one of claims 1 to 14 to the surface of a substrate; as well as The composition on the substrate is irradiated to obtain the cured product.

16. A cured product formed according to the method of claim 15 and disposed on a substrate.

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