Photocurable silicone composition, sealing material and sheet film

Abstract

To provide a photocurable silicone composition capable forming a cured product having excellent hardness and transparency.SOLUTION: There is provided a photocurable silicone composition which comprises (A) a resinous organopolysiloxane containing a thiol group which contains at least two thiol groups per molecule and at least one SiO4 / 2 (Q unit) or one siloxane unit (T unit) represented by R-SiO3 / 2 (provided that R means a monovalent organic group); (B) a silicone reactive diluent selected from an organic silane compound containing at least two alkenyl groups per molecule, a cyclic organopolysiloxane containing at least two alkenyl groups per molecule, an organopolysiloxane compound comprising a siloxane unit (M unit) and a Q unit represented by R3-SiO1 / 2 which contains at least two alkenyl groups per molecule and a mixture thereof; (C) at least one a photopolymerization initiator; (D) at least one polymerization inhibitor and / or antioxidant.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photocurable silicone composition and an encapsulant or sheet film formed from the photocurable silicone composition. [Background technology]

[0002] Curable silicone compositions are used in a wide range of industrial fields because they form cured products with excellent heat resistance, cold resistance, electrical insulation, weather resistance, water repellency, and transparency. Cured products of such curable silicone compositions are less susceptible to discoloration than other organic materials, and also suffer less deterioration in physical properties, making them suitable as optical materials and sealing materials for semiconductor devices.

[0003] Among curable silicone compositions, photocurable silicone compositions are used in several products because they can avoid problems such as shape shrinkage during molding and damage to electronic components that are caused by heating the curable silicone composition.

[0004] In photocurable silicone compositions, a mercapto-functional compound may be blended for the purpose of improving the shape stability of the cured product, etc. To date, several applications for photocurable silicone compositions containing mercapto-functional compounds have been published.

[0005] For example, Patent Document 1 describes a UV-curable silicone composition that includes: A) an alkenyl-containing organopolysiloxane having at least two alkenyl groups in each molecule and having at least one alkenyl group at each end; B) a photoinitiator; C) a mercapto-functional organopolysiloxane containing two or more mercapto groups per molecule; D) a pigment; and E) one or both of silica and F) a solvent containing an organopolysiloxane having 12 or fewer silicon atoms.

[0006] Furthermore, Cited Document 2 describes an ultraviolet-curable silicone resin composition comprising: (A) a linear polyorganosiloxane containing an aliphatic unsaturated group; (B) a polyorganosiloxane containing a mercaptoalkyl group bonded to a silicon atom and having a viscosity of 10 to 10,000 cP at 23° C.; (C) an acylphosphine oxide-based photoinitiator; and (D) a compound that is compatible with (A) and (B) and with (C) and has a boiling point of 200° C. or higher, wherein the ratio of the number of mercaptoalkyl groups in (B) to the number of aliphatic unsaturated groups in (A) is 0.1 to 10, and (C) is 0.1 to 0.5% by weight and (D) is 0.1 to 2.0% by weight in a total of 100% by weight of (A) to (D).

[0007] Furthermore, Patent Document 3 describes a photocurable liquid silicone composition that contains (A) an organosilane or low molecular weight organosiloxane having 1 to 5 silicon atoms, at least two alkenyl groups in one molecule, and at least two monovalent functional groups selected from aromatic groups and aralkyl groups, (C) a compound having at least two mercapto groups in one molecule, and (D) a photoradical initiator, and that has a refractive index of the entire liquid composition before curing of 1.48 or greater.

[0008] Patent Document 4 describes a UV-curable silicone composition comprising: (A) at least one organopolysiloxane having at least two alkenyl groups per molecule; (B) at least one mercapto-functional compound having at least two thiol groups per molecule; (C) at least one photopolymerization initiator; and (D) (d-1) a polymerization inhibitor comprising at least one alkoxylated polyol-derived (meth)acrylate or at least one quinone derivative compound, and / or (d-2) at least one antioxidant; wherein the (C) photopolymerization initiator is selected from intramolecular hydrogen abstraction photopolymerization initiators, or the (ii) composition comprises the (d-1) polymerization inhibitor.

[0009] However, although photocurable silicone compositions containing mercapto-functional compounds have excellent shape stability when cured, they suffer from the problem that they may exhibit insufficient hardness. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] International Publication WO2018 / 223365 [Patent Document 2] Patent Publication No. 2013-253179 [Patent Document 3] International Publication WO2021 / 167051 [Patent Document 4] Patent Publication No. 2022-19171 Summary of the Invention [Problem to be solved by the invention]

[0011] An object of the present invention is to provide a photocurable silicone composition containing at least one thiol-functional organopolysiloxane that is capable of forming a cured product that has excellent hardness and transparency. [Means for solving the problem]

[0012] The object of the present invention is to (A) At least two thiol groups and at least one SiO 4 / 2 (Q units) or R-SiO 3 / 2 a resin-like thiol group-containing organopolysiloxane containing a siloxane unit (T unit) represented by the following formula (where R represents a monovalent organic group, for example a monovalent hydrocarbon group; the same applies hereinafter); (B) an organosilane compound containing at least two alkenyl groups per molecule, a cyclic organopolysiloxane containing at least two alkenyl groups per molecule, R-SiO 1 / 2a silicone reactive diluent selected from organopolysiloxane compounds consisting of siloxane units (M units) and Q units represented by the following formula: (C) at least one photoinitiator; and (D) at least one polymerization inhibitor and / or antioxidant; This can be achieved by a photocurable silicone composition comprising:

[0013] (A) The resinous thiol group-containing organopolysiloxane preferably has thiol groups as pendant groups and does not have thiol groups in the M units.

[0014] (A) The resin-like thiol group-containing organopolysiloxane is preferably R2-SiO 2 / 2 It does not contain siloxane units (D units) represented by the following formula:

[0015] (B) The silicone reactive diluent may have a number average molecular weight of less than 800.

[0016] The (C) photopolymerization initiator may include an alkylphenone-type photopolymerization initiator.

[0017] (D) The polymerization inhibitor and / or antioxidant may be selected from (d-2) antioxidants.

[0018] (d-2) The antioxidant may include 2,6-di-tert-butyl-4-methylphenol (BHT).

[0019] (B) The silicone reactive diluent may be included in an amount greater than 2 weight percent, based on the total weight of the photocurable silicone composition.

[0020] The present invention also relates to an encapsulant or sheet film formed from the photocurable silicone composition of the present invention. Effect of the Invention

[0021] The photocurable silicone composition of the present invention contains a thiol group-containing organopolysiloxane and is capable of forming a cured product that has excellent hardness and transparency. In particular, the cured product of the present invention is capable of maintaining its excellent transparency even after heat treatment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] As a result of extensive investigations, the inventors surprisingly discovered that a photocurable silicone composition comprising a thiol group-containing organopolysiloxane having a specific structure and a predetermined amount of a silicone-reactive diluent containing at least two alkenyl groups per molecule is capable of forming a cured product that has excellent hardness and transparency, and thus completed the present invention.

[0023] Therefore, the composition according to the present invention (A) At least two thiol groups and at least one SiO 4 / 2 or R-SiO 3 / 2 A resin-like thiol group-containing organopolysiloxane containing a siloxane unit represented by the formula: (B) a silicone reactive diluent selected from organosilane compounds containing at least two alkenyl groups per molecule, cyclic organopolysiloxanes containing at least two alkenyl groups per molecule, organopolysiloxane compounds consisting of M and Q units containing at least two alkenyl groups per molecule, and mixtures thereof; (C) at least one photoinitiator; and (D) at least one polymerization inhibitor and / or antioxidant; The photocurable silicone composition comprises:

[0024] The composition, sealing material, and sheet film of the present invention will be described in more detail below.

[0025] [Photocurable composition] The photocurable composition of the present invention comprises (A) at least two thiol groups and at least one SiO 4 / 2 or R-SiO 3 / 2(B) a silicone reactive diluent selected from an organosilane compound containing at least two alkenyl groups per molecule, a cyclic organopolysiloxane containing at least two alkenyl groups per molecule, an organopolysiloxane compound consisting of M units and Q units containing at least two alkenyl groups per molecule, and mixtures thereof; (C) at least one photopolymerization initiator; and (D) at least one polymerization inhibitor and / or antioxidant. Each component will be described in more detail below.

[0026] (A) At least two thiol groups and at least one SiO 4 / 2 or R-SiO 3 / 2 A resin-like thiol group-containing organopolysiloxane containing a siloxane unit represented by the formula: The photocurable silicone composition of the present invention contains, as component (A), at least two thiol groups and at least one SiO 4 / 2 or R-SiO 3 / 2 The photocurable silicone composition according to the present invention may contain one type of (A) thiol group-containing organopolysiloxane, or may contain two or more types of (A) thiol group-containing organopolysiloxanes.

[0027] The molecular structure of the thiol group-containing organopolysiloxane (A) is resin-like. In this specification, resin-like means that the molecular structure has a branched or three-dimensional network structure. Specifically, the resin-like thiol group-containing organopolysiloxane of component (A) has at least one SiO 4 / 2 or at least one R—SiO 3 / 2The thiol group-containing organopolysiloxane (A) may contain either Q or T units, or may contain both Q and T units. In one embodiment, the term "resin-like" as used herein means an organopolysiloxane in which the ratio of the total amount of T and Q units to the total amount of siloxane units in one molecule is 5% or more, or 10% or more. In addition, in this specification, the resin-like organopolysiloxane usually has a number average molecular weight of 800 or more. In addition, in this specification, the resin-like organopolysiloxane usually has a viscosity of 1 mPa or more at 25°C. In addition, in this specification, the number average molecular weight of the organopolysiloxane component can be measured by GPC, and the viscosity of the organopolysiloxane component can be measured by a rotational viscometer in accordance with JIS K7117-1.

[0028] (A) Resin-like thiol group-containing organopolysiloxane has at least two thiol groups per molecule. Resin-like thiol group-containing organopolysiloxane may have a thiol group at the end of the polymer chain, or may have a thiol group on a silicon atom other than the end of the polymer chain, i.e., as a pendant group. In the present specification, a thiol group is a group represented by R-SH (where R represents an organic group, such as a hydrocarbon chain), and examples of the thiol group include alkylthiol groups, and more specifically, C1 to C 12 An example is an alkylthiol group.

[0029] Examples of silicon-bonded organic groups other than thiol groups contained in component (A) include C groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups. 1~12 Alkyl groups: C such as phenyl, tolyl, xylyl, and naphthyl groups 6~12 Aryl groups; C such as benzyl, phenethyl and phenylpropyl groups 7~12Aralkyl groups: vinyl groups, allyl groups, butenyl groups, pentenyl groups, hexenyl groups, heptenyl groups, octenyl groups, nonenyl groups, decenyl groups, undecenyl groups, dodecenyl groups, etc. 2~12 alkenyl groups; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, chlorine, or bromine atoms. A small amount of hydroxyl groups or alkoxy groups such as methoxy and ethoxy groups may be bonded to the silicon atoms in component (A) as long as the object of the present invention is not impaired. The groups bonded to silicon atoms other than thiol groups are preferably C 1~12 It is selected from alkyl groups, in particular methyl groups.

[0030] (A) resin-like thiol group-containing organopolysiloxane may or may not contain an alkenyl group, but preferably does not contain one.Furthermore, (A) resin-like thiol group-containing organopolysiloxane may or may not contain an aryl group, but preferably does not contain one.

[0031] In one embodiment of the present invention, the resinous thiol group-containing organopolysiloxane (A) is represented by the following formula (Ia): Average unit formula (Ia):(R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d (XO 1 / 2 ) e [In the formula, R 1 are the same or different monovalent hydrocarbon groups which may be substituted with at least one halogen, provided that at least two R 1represents a thiol group-containing organic group, X represents a hydrogen atom or an alkyl group, 0 ≦ a < 1, 0 ≦ b < 1, 0 ≦ c < 0.95, 0 ≦ d < 0.9, 0 ≦ e < 0.4, 0 < c + d < 0.95, and a + b + c + d = 1.0 are satisfied. e represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms) when the total number of silicon atoms is 1). It can be an organopolysiloxane resin that can be represented by

[0032] The thiol group-containing organic group is not particularly limited, but preferably an alkylthiol group. More specifically, C1 to C 12 An alkylthiol group can be mentioned.

[0033] In the above formula (I-a), R 1 Examples of the monovalent hydrocarbon group which may be halogen-substituted and other than the thiol group-containing organic group in are the silicon atom-bonded organic groups other than the above-mentioned thiol groups. Preferably, an alkyl group having 1 to 12 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a cyclohexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group; groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms. R 1 May be a small amount of hydroxyl groups, alkoxy groups such as methoxy groups and ethoxy groups, as long as the object of the present invention is not impaired. R other than the thiol group-containing organic group 1 Is preferably an alkyl group having 1 to 6 carbon atoms, particularly a methyl group.

[0034] X in the above formula (I-a) is a hydrogen atom or an alkyl group. As the alkyl group of X, an alkyl group having 1 to 3 carbon atoms is preferable, and specifically, a methyl group, an ethyl group, and a propyl group are exemplified.

[0035] In the above formula (Ia), a is preferably in the range of 0.1≦a≦0.8, more preferably in the range of 0.2≦a≦0.65, and even more preferably in the range of 0.3≦a≦0.5. In the above formula (Ia), b is preferably in the range of 0≦b≦0.5, more preferably in the range of 0≦b≦0.3, and particularly in the range of 0≦b≦0.1. In the above formula (Ia), c is preferably in the range of 0.1≦c<0.8, more preferably in the range of 0.2≦c≦0.65, and particularly in the range of 0.3≦c≦0.5. In the above formula (Ia), d is preferably in the range of 0.04≦d≦0.4, more preferably in the range of 0.08≦d≦0.3, and particularly in the range of 0.05≦d≦0.2. In the above formula (Ia), e is preferably in the range of 0≦e≦0.3, more preferably in the range of 0≦e≦0.25, and particularly in the range of 0≦e≦0.2. In addition, in formula (Ia), c+d is preferably in the range of 0.15≦c+d≦0.9, more preferably in the range of 0.3≦c+d≦0.8, and particularly preferably in the range of 0.45≦c+d≦0.7.

[0036] In a preferred embodiment of the present invention, the resin-like thiol group-containing organopolysiloxane has thiol groups on silicon atoms other than those at the ends of the polymer chain, i.e., as pendant groups, and has no thiol groups in the M units.

[0037] Therefore, in one embodiment of the present invention, the resinous thiol group-containing organopolysiloxane (A) is represented by the following formula (Ib): Average unit formula (Ib):(R 2 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d (XO 1 / 2 ) e [In the formula, R 2is a monovalent hydrocarbon group which may be the same or different and may be substituted with at least one halogen other than a thiol-containing organic group, R 1 is a monovalent hydrocarbon group which may be the same or different and may be substituted with at least one halogen, provided that in one molecule, at least two Rs 1 represents a thiol group-containing organic group, X represents a hydrogen atom or an alkyl group, 0 ≦ a < 1, 0 ≦ b < 1, 0 ≦ c < 0.95, 0 < d < 0.9, 0 ≦ e < 0.4, and a + b + c + d = 1.0 is satisfied. e represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms) when the total number of silicon atoms is 1).] It can be an organopolysiloxane resin that can be represented by

[0038] Regarding the thiol group-containing organic group and the monovalent hydrocarbon group which may be halogen-substituted, it is as described in the above formula (I-a). Also, regarding the definitions and preferred ranges of X, a, b, c, d, and e, it is as described in the above formula (I-a).

[0039] In a preferred embodiment of the present invention, the (A) resinous thiol group-containing organopolysiloxane may or may not contain a siloxane unit (D unit) represented by R2-SiO 2 / 2 but preferably does not contain it. In this preferred embodiment, preferably, the thiol group-containing organic group is bonded to a siloxane unit (T unit) represented by R-SiO 3 / 2

[0040] Therefore, in one embodiment of the present invention, the (A) resinous thiol group-containing organopolysiloxane has the following formula (I-c): Average unit formula (I-b): (R 2 3SiO 1 / 2 ) a (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d (XO 1 / 2 ) e [In the formula, R 2 ​is a monovalent hydrocarbon group which may be the same or different and may be substituted with at least one halogen other than a thiol-containing organic group, and R 1 is a monovalent hydrocarbon group which may be the same or different and may be substituted with at least one halogen, provided that in one molecule, at least two Rs 1 represents a thiol group-containing organic group, X represents a hydrogen atom or an alkyl group, 0 ≦ a < 1, 0 ≦ c < 0.95, 0 < d < 0.9, 0 ≦ e < 0.4, and a + c + d = 1.0 is satisfied. e represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms) when the total number of silicon atoms is 1).] can be an organopolysiloxane resin represented by

[0041] Regarding the thiol group-containing organic group and the monovalent hydrocarbon group which may be halogen-substituted, it is as described in the above formula (I-a). Also, regarding the definitions and preferred ranges of X, a, c, d, and e, it is as described in the above formula (I-a). Regarding it, it is as described in the above formula (I-a).

[0042] (A) The amount of the thiol group-containing organic group relative to the total amount of the silicon atom-bonded organic groups in the resinous thiol group-containing organopolysiloxane is not particularly limited, but relative to the total amount of the silicon atom-bonded organic groups, for example, it is 1 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, particularly 15 mol% or more, and usually 50 mol% or less, preferably 40 mol%, more preferably 35 mol% or less. The content of the thiol group can be measured by an analytical method such as a Fourier transform infrared spectrophotometer (FT-IR), nuclear magnetic resonance (NMR), etc.

[0043] (A) The viscosity of the resinous thiol group-containing organopolysiloxane is not particularly limited, but for example, it can be 5 mPa to 20,000 mPa at 25°C. In this specification, the viscosity of the organopolysiloxane component can be measured with a rotational viscometer conforming to JIS K7117-1.

[0044] The number average molecular weight of the (A) resinous thiol group-containing organopolysiloxane is not particularly limited, but is, for example, within the range of 800 to 100,000. In this specification, the number average molecular weight can be measured by GPC.

[0045] The (A) component may be contained in an amount of 5 mass % or more, preferably 10 mass % or more, more preferably 15 mass % or more, and particularly preferably 20 mass % or more, based on the total mass of the composition, and the (A) component may be contained in an amount of 90 mass % or less, preferably 80 mass % or less, based on the total mass of the composition.

[0046] The component (A) may be contained in an amount of 5 to 90 mass %, preferably 10 to 85 mass % or more, more preferably 15 to 80 mass %, and particularly preferably 20 to 80 mass %, based on the total mass of the composition.

[0047] (B) Silicone reactive diluent The photocurable silicone composition according to the present invention comprises, as component (B), a silicone reactive diluent containing at least two alkenyl groups per molecule. The composition according to the present invention may comprise one type of silicone reactive diluent (B) or a combination of two or more types of silicone reactive diluents (B).

[0048] (B) The silicone reactive diluent is selected from organosilane compounds containing at least two alkenyl groups per molecule, cyclic organopolysiloxanes containing at least two alkenyl groups per molecule, organopolysiloxane compounds consisting of M and Q units containing at least two alkenyl groups per molecule, and mixtures thereof.

[0049] (B) The silicone reactive diluent is liquid at room temperature and can function as a distribution aid that reduces the viscosity of the curable silicone composition and increases its fluidity. The silicone reactive diluent can also function as a curing accelerator.

[0050] Examples of the alkenyl group contained in component (B) include alkenyl groups having 2 to 12 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl groups, and preferably vinyl groups.

[0051] The organosilane compound having at least two alkenyl groups per molecule of component (B) is also referred to as a polyunsaturated silane, and the type thereof is not particularly limited, but may be selected from monosilane compounds such as dimethyldivinylsilane, methyltrivinylsilane, tetravinylsilane, diallylmethylsilane, diallyldimethylsilane, and the like.

[0052] The cyclic organopolysiloxane having at least two alkenyl groups per molecule of component (B) is preferably Average structural formula (II-a):(R 4 2SiO) n (In formula (II-a), R 4 are the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups, provided that at least two R 4 is an alkenyl group, and n is 4 to 15, preferably 4 to 10, and more preferably 4 to 8.

[0053] In the above formula (II-a), R 4 is R 1The same ones are applicable, preferably, an alkyl group having 1 to 12 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group; an aryl group having 6 to 20 carbon atoms such as phenyl group, tolyl group, xylyl group, naphthyl group; an alkenyl group having 2 to 12 carbon atoms such as vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group; a group in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine atom, chlorine atom, bromine atom. R 4 is preferably selected from an alkyl group having 1 to 6 carbon atoms, particularly a methyl group, and an alkenyl group having 2 to 6 carbon atoms, particularly a vinyl group.

[0054] The organopolysiloxane compound composed of M unit and Q unit having at least two alkenyl groups per molecule of component (B) is R3-SiO 1 / 2 The siloxane unit (M unit) represented by and SiO 4 / 2 It is an organopolysiloxane composed only of the siloxane unit (Q unit) represented by. The organopolysiloxane compound of component (B) can preferably be represented by the following average unit formula (II-b). Average unit formula (II-b): (R 4 3SiO 1 / 2 ) s (SiO 4 / 2 ) t In the formula, R 4 is the same or different halogen-substituted or unsubstituted monovalent hydrocarbon group, provided that in one molecule, at least two R 4 are alkenyl groups, 0 < s < 1, 0 < t < 1, and s + t = 1.

[0055] R in formula (II-b) 4 is as described in formula (II-a).

[0056] In formula (II-b), s is preferably in the range of 0.3≦s≦0.95, more preferably in the range of 0.5≦s≦0.9, and even more preferably in the range of 0.7≦s≦0.85. In formula (II-b), t is preferably in the range of 0.05≦t≦0.5, more preferably in the range of 0.1≦t≦0.4, and particularly preferably in the range of 0.15≦t≦0.3.

[0057] The viscosity of the organopolysiloxane compound consisting of M units and Q units and having at least two alkenyl groups per molecule of component (B) is not particularly limited, but can usually be from 0.1 mPa to 1,000 mPa at 25°C.

[0058] The content of alkenyl groups in the total silicon-bonded organic groups of the cyclic organopolysiloxane and / or organopolysiloxane compound consisting of M and Q units of component (B) is not particularly limited, but may be, for example, 10 mol% or more, preferably 20 mol% or more, more preferably 30 mol% or more of the total silicon-bonded organic groups, and 70 mol% or less, preferably 60 mol% or less, more preferably 55 mol% or less of the total silicon-bonded organic groups. Note that, in this specification, the content of alkenyl groups contained in the organopolysiloxane component can be determined, for example, by an analytical method such as Fourier transform infrared spectrophotometer (FT-IR) or nuclear magnetic resonance (NMR), or by the following titration method.

[0059] This section explains how to quantify the amount of alkenyl groups in each component by titration. The alkenyl group content in organopolysiloxane components can be accurately quantified by a titration method commonly known as the Wyss method. The principle is as follows. First, alkenyl groups in the organopolysiloxane raw material are subjected to an addition reaction with iodine monochloride as shown in formula (1). Next, excess iodine monochloride is reacted with potassium iodide and liberated as iodine by the reaction shown in formula (2). The liberated iodine is then titrated with a sodium thiosulfate solution. Equation (1) CH2=CH- + 2ICl → CH2I-CHCl- + ICl (excess) Formula (2) ICl+KI → I2+ KCl The amount of alkenyl groups in the component can be quantified from the difference between the amount of sodium thiosulfate required for titration and the amount of a separately prepared blank solution.

[0060] (B) the silicone reactive diluent preferably has a number average molecular weight of less than 800. More preferably, (B) the silicone reactive diluent has a number average molecular weight of not more than 500. The lower limit of the number average molecular weight of component (B) is not particularly limited, but is usually 100 or more.

[0061] The viscosity of the (B) silicone reactive diluent is not particularly limited, but can usually be from 0.1 mPa to 1,000 mPa at 25°C.

[0062] In one embodiment of the present invention, the (B) component is contained in an amount of more than 2 mass% based on the total mass of the photocurable silicone composition of the present invention. The content of the (B) component is preferably 3 mass% or more, more preferably 5 mass% or more, and even more preferably 7 mass% or more, based on the total mass of the photocurable silicone composition of the present invention. The content of the (B) component may be 70 mass% or less, more preferably 60 mass% or less, and even more preferably 50 mass% or less, based on the total mass of the photocurable silicone composition of the present invention. The content of the (B) component may be in the range of 3 to 70 mass%, preferably in the range of 5 to 60 mass%, and even more preferably in the range of 7 to 50 mass%, based on the total mass of the photocurable silicone composition.

[0063] In one embodiment of the present invention, when component (B) contains an organopolysiloxane compound consisting of M units and Q units, the content of the organopolysiloxane compound is preferably 3 mass% or more, more preferably 4 mass% or more, and preferably 40 mass% or less, more preferably 30 mass% or less, even more preferably 20 mass% or less, and particularly preferably 10 mass% or less, based on the total mass of the photocurable silicone composition of the present invention. The content of the organopolysiloxane compound as component (B) may be within the range of 3 to 40 mass%, 3 to 30 mass%, 4 to 20 mass%, or 4 to 10 mass%, based on the total mass of the photocurable silicone composition of the present invention.

[0064] (C) Photopolymerization initiator The photocurable silicone composition according to the present invention contains at least one photopolymerization initiator as component (C). The composition according to the present invention may contain one type of (C) photopolymerization initiator, or may contain a combination of two or more types of (C) photopolymerization initiators.

[0065] The type of (C) photopolymerization initiator is not particularly limited, but may be selected from alkylphenone-type photopolymerization initiators, acylphosphine oxide-type photopolymerization initiators, intramolecular hydrogen abstraction-type photopolymerization initiators, and oxime ester-type photopolymerization initiators.

[0066] Alkylphenone type photoinitiators are, for example, 1-hydroxycyclohexyl-phenyl ketone, sold under the name Omnirad 184 by IGM RESINS BV; 2-hydroxy-2-methyl-1-phenyl-1-propanone, sold under the name Omnirad 1173 by IGM RESINS BV; 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, oligo-[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)-phenyl]-propanone], sold under the name Omnirad 2959 by IGM RESINS BV; hydroxyacetophenones such as 1,1'-(methylene-di-4,1-phenylene)bis[2-hydroxy-2-methyl-1-propanone], sold under the name Omnirad 127 by IGM RESINS BV; 2-Methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-propan-1-one sold under the name 907 by IGM RESINS BV, 2-Dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one sold under the name Omnirad 379EG by IGM RESINS BV, 2-benzyl-2-dimethylamino-1-(3,4-dimethoxy-phenyl)-butan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholin-4-yl-phenyl)-butan-1-one sold under the name Omnirad 369 by IGM RESINS Aminoacetophenones such as 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone and 2-methyl-1-(4-methylsulfanyl-phenyl)-2-morpholin-4-yl-propan-1-one, sold by BV; 2,2-dimethoxy-2-phenylacetophenone, 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, 4-t-butyltrichloroacetophenone, and combinations thereof.

[0067] The acylphosphine oxide type photoinitiator may be selected, for example, from (2,4,6-trimethylbenzoyl)-diphenyl-phosphine oxide sold by IGM RESINS BV under the name Omnirad TPO-H, phenyl-(2,4,6-trimethylbenzoyl)-phosphoric acid ethyl ester sold by IGM RESINS BV under the name Omnirad TPO-L, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide sold by IGM RESINS BV under the name Omnirad 819, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and combinations thereof.

[0068] The hydrogen abstraction type photoinitiator may be chosen from oxyphenyl type photoinitiators, such as methylbenzoylformate, for example, sold under the name Omnirad MBF by IGM RESINS BV.

[0069] In particular, the photopolymerization initiator may include oxyethoxyphenylacetyl derivatives, which also fall under the category of intramolecular hydrogen abstraction type photopolymerization initiators. As a specific example of oxyethoxyphenylacetyl derivatives, mention may be made of a blend of oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester and oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester, sold by IGM RESINS BV under the name Omnirad 754, and mixtures thereof.

[0070] The oxime ester type photoinitiator may be selected from, for example, 1-[4-(phenylthio)phenyl]-1,2-octanedione-2-(o-benzoyloxime), sold by BASF under the name Irgacure OXE-01, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone-1-(o-acetyloxime), sold by BASF under the name Irgacure OXE-01, and combinations thereof.

[0071] In another embodiment of the present invention, the (C) photopolymerization initiator is: (C-1) α-Hydroxyacetophenone (C-2) A combination of α-hydroxyacetophenone and α-aminoalkylphenone, or (C-3) Combination of α-hydroxyacetophenone and monoacylphosphine oxide may include.

[0072] Examples of α-hydroxyacetophenone include 2-hydroxy-2-methyl-1-phenyl-1-propanone (IGM Resins BV, product name: Omnirad 1173), 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (IGM Resins BV, product name: Omnirad 2959), oligo-[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)-phenyl]-propanone], 1,1'-(methylene-di-4,1-phenylene)bis[2-hydroxy-2-methyl-1-propanone] (IGM Resins BV, product name: Omnirad 127D), and 1-hydroxycyclohexyl-phenyl ketone (IGM Resins BV, product name: Omnirad 184).

[0073] The photopolymerization initiator (C-1) may further contain a compound having an acetophenone structure other than α-hydroxyacetophenone in addition to α-hydroxyacetophenone. Such a compound having an acetophenone structure is not particularly limited, but may include, for example, 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, 4-t-butyltrichloroacetophenone, and diethoxyacetophenone.

[0074] In a particularly preferred embodiment, the (C-1) photoinitiator comprising α-hydroxyacetophenone contains only α-hydroxyacetophenone and does not contain other photoinitiators, or the amount of other photoinitiators is 10 mass % or less, 5 mass % or less, or 3 mass % or less, based on the total mass of the (C) component.

[0075] Examples of the α-aminoalkylphenone in the combination of (C-2) α-hydroxyacetophenone and α-aminoalkylphenone include 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-propan-1-one (manufactured by IGM Resins BV, product name: Omnirad 907), 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one (manufactured by IGM Resins BV, product name: Omnirad 379EG), 2-benzyl-2-dimethylamino-1-(3,4-dimethoxy-phenyl)-butan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholin-4-yl-phenyl)-butan-1-one, 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone (IGM Resins Examples of suitable amines include 2-methyl-1-(4-methylsulfanyl-phenyl)-2-morpholin-4-yl-propan-1-one (manufactured by BV, product name: Omnirad 369) and 2-methyl-1-(4-methylsulfanyl-phenyl)-2-morpholin-4-yl-propan-1-one.

[0076] In the combination of (C-2) α-hydroxyacetophenone and α-aminoalkylphenone, the mass ratio of (C-2) α-hydroxyacetophenone to α-aminoalkylphenone is not particularly limited, but for example, the mass ratio of α-hydroxyacetophenone to α-aminoalkylphenone may be 0.1 to 100, preferably 0.5 to 50, and more preferably 1 to 20.

[0077] In a particularly preferred embodiment, (C-2) the photoinitiator comprising a combination of α-hydroxyacetophenone and α-aminoalkylphenone consists only of α-hydroxyacetophenone and α-aminoalkylphenone, and does not contain any other photoinitiators, or the amount of other photoinitiators is 10 mass % or less, 5 mass % or less, or 1 mass % or less, based on the total mass of component (C).

[0078] Examples of the monoacylphosphine oxide in the combination of (C-3) α-hydroxyacetophenone and monoacylphosphine oxide include 2,4,6-trimethylbenzoyl)-diphenyl-phosphine oxide (manufactured by IGM Resins BV, product name: Omnirad TPO-H) and phenyl-(2,4,6-trimethylbenzoyl)-phosphinic acid ethyl ester (manufactured by IGM Resins BV, product name: Omnirad TPO-L).

[0079] In the (C-3) combination of α-hydroxyacetophenone and monoacylphosphine oxide, the mass ratio of α-hydroxyacetophenone to monoacylphosphine oxide is not particularly limited, but for example, the mass ratio of α-hydroxyacetophenone to monoacylphosphine oxide may be 0.1 to 100, preferably 0.5 to 50, and more preferably 0.8 to 20.

[0080] In a particularly preferred embodiment, (C-3) the photopolymerization initiator comprising a combination of α-hydroxyacetophenone and monoacylphosphine oxide consists only of α-hydroxyacetophenone and monoacylphosphine oxide and does not contain any other photoinitiators, or the amount of other photoinitiators is 10 mass % or less, 5 mass % or less, or 1 mass % or less, based on the total mass of the component (C).

[0081] In the present specification, examples of "other photoinitiators" include, but are not limited to, photopolymerization initiators other than those listed as the components (C-1) to (C-3) above, such as bisacylphosphine oxide, trisacylphosphine oxide, phenylglyoxalate, thioxanthone, benzoin ether, oxime ester, etc. The photopolymerization initiator (C) of the present invention may contain no photopolymerization initiators other than α-hydroxyacetophenone, α-aminoalkylphenone, and monoacylphosphine oxide, or may contain them in an amount of 10% by mass or less, 5% by mass or less, or 1% by mass or less based on the total mass of the component (C).

[0082] In one specific embodiment of the present invention, the (C) photopolymerization initiator is preferably selected from alkylphenone-type photopolymerization initiators. In another specific embodiment of the present invention, the (C) photopolymerization initiator contains only alkylphenone-type photopolymerization initiators and does not contain other photopolymerization initiators.

[0083] In one particular embodiment of the present invention, the (C) photoinitiator does not contain any phosphorus atoms.

[0084] The (C) photopolymerization initiator may be contained in an amount of 0.001 mass% or more, preferably 0.005 mass% or more, more preferably 0.01 mass% or more, and even more preferably 0.05 mass% or more, based on the total mass of the composition, and can be contained in an amount of 5 mass% or less, preferably 3 mass% or less, more preferably 2 mass% or less, and even more preferably 1.5 mass% or less.

[0085] (D) Photopolymerization inhibitors and / or antioxidants The photocurable silicone composition according to the present invention contains either or both of at least one photopolymerization inhibitor as component (d-1) and / or at least one antioxidant as component (d-2).

[0086] (d-1) Photopolymerization inhibitor (d-1) The photopolymerization inhibitor may contain one type of photopolymerization inhibitor, or may contain a combination of two or more types of photopolymerization inhibitors.

[0087] The (d-1) photopolymerization inhibitor of the present invention includes at least one alkoxylated polyol-derived (meth)acrylate or at least one quinone derivative compound. The term "alkoxylated polyol-derived (meth)acrylate" may mean a (meth)acrylate having a partial structure derived from "alkoxylated polyol".

[0088] The alkoxylated polyol-derived (meth)acrylate can be a monofunctional alkoxylated polyol-derived (meth)acrylate or a multifunctional alkoxylated polyol-derived (meth)acrylate that is difunctional, trifunctional, or tetrafunctional.

[0089] The polyol portion of the alkoxylated polyol-derived (meth)acrylate may be selected from dihydric to octahydric polyols. Examples of dihydric to octahydric polyols include dihydric alcohols such as ethylene glycol, propylene glycol, butylene glycol, hexamethylene glycol, and neopentyl glycol, glycerol, trioxyisobutane, 1,2,3-butanetriol, 1,2,3-pentanetriol, 2-methyl-1,2,3-propanetriol, 2-methyl-2,3,4-butanetriol, 2-ethyl-1,2,3-butanetriol, 2,3,4-pentanetriol, 2,3,4-hexanetriol, 4-propyl-3,4,5-heptanetriol, 2,4-dimethyl-2,3,4 trihydric alcohols such as 1,2,4-pentanetriol, pentamethylglycerol, pentaglycerol, 1,2,4-butanetriol, 1,2,4-pentanetriol, trimethylolethane, and trimethylolpropane; and tetrahydric alcohols such as pentaerythritol, 1,2,3,4-pentanetetrol, 2,3,4,5-hexanetetrol, 1,2,4,5-pentanetetrol, and 1,3,4,5-hexanetetrol.

[0090] The alkoxylated moiety of the alkoxylated polyol-derived (meth)acrylate may be selected from a methoxylated moiety, an ethoxylated moiety, a butoxylated moiety, and a propoxylated moiety. The repeat number of the alkoxylated moiety of the alkoxylated polyol-derived (meth)acrylate is not particularly limited, but is usually 1 to 30, preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5.

[0091] Among the monofunctional alkoxylated polyol-derived (meth)acrylates there may be mentioned methoxyethylene glycol acrylate, methoxypolypropylene glycol acrylate, methoxypolyethylene glycol acrylate, ethoxydiethylene glycol acrylate, and neopentyl glycol propoxylate methyl ether monoacrylate.

[0092] As difunctional alkoxylated polyol-derived (meth)acrylates, mention may be made of alkoxylated neopentyl glycol diacrylates, such as ethoxylated neopentyl glycol diacrylate and propoxylated neopentyl glycol diacrylate.

[0093] Among the trifunctional alkoxylated polyol-derived (meth)acrylates, mention may be made of ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, and propoxylated glycerol triacrylate.

[0094] As an example of a (meth)acrylate derived from a tetrafunctional alkoxylated polyol, mention may be made of ethoxylated pentaerythritol tetraacrylate.

[0095] The quinone derivative compound may be a quinone methide compound. As a specific embodiment of the quinone methide compound, mention may be made of 2,6-bis(1,1-dimethylethyl)-4-(phenylenemethylene)cyclohexa-2,5-dien-1-one, sold under the name Irgastab® UV22 by BASF.

[0096] In one embodiment of the present invention, the (d-1) photopolymerization inhibitor may be preferably selected from polyfunctional alkoxylated polyol-derived (meth)acrylates, in particular trifunctional alkoxylated polyol-derived (meth)acrylates.

[0097] The (d-1) photopolymerization inhibitor may be contained in an amount of 0.001 mass% or more, preferably 0.005 mass% or more, more preferably 0.01 mass% or more, and even more preferably 0.03 mass% or more, based on the total mass of the composition, and may be contained in an amount of 10 mass% or less, preferably 5 mass% or less, more preferably 3 mass% or less, and even more preferably 2 mass% or less.

[0098] (d-2) Antioxidants The (d-2) antioxidant may include one type of antioxidant or a combination of two or more types of antioxidants.

[0099] Such antioxidants include, but are not limited to, hindered phenol-based antioxidants, phosphorus-based antioxidants, lactone-based antioxidants, hydroxylamine-based antioxidants, vitamin E-based antioxidants, and sulfur-based antioxidants.

[0100] Hindered phenolic antioxidants include, for example, triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] available from BASF under the name IRGANOX 245, 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] available from BASF under the name IRGANOX 259, 4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine available from BASF under the name IRGANOX 565, pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] available from BASF under the name IRGANOX 1010, 2,2-Thio-diethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] available from BASF under the name IRGANOX 1035; octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate available from BASF under the name IRGANOX 1076; N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxyhydrocinnamide) available from BASF under the name IRGANOX 1098; 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester available from BASF under the name IRGAMOD 295; 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene available from BASF under the name IRGANOX 1330; tris-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate available from BASF under the name IRGANOX 3114, octylated diphenylamine available from BASF under the name IRGANOX 5057, 2,4-bis[(octylthio)methyl)-o-cresol available from BASF under the name IRGANOX 1520L, isooctyl-3-(3,5-di-tert-butyl-4-hydroxyphenylpropionate available from BASF under the name IRGANOX 1135, 2,4-bis[(octylthio)methyl)-o-cresol available from BASF under the name IRGANOX 1726,Mention may be made of 4-bis(dodecylthiomethyl)-6-methylphenol, 2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)chroman-6-ol available from BASF under the name IRGANOX E201, and 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)benzofuran-2(3H)-one available from BASF under the name IRGANOX HP-136, as well as combinations thereof.

[0101] As phosphorus antioxidants, mention may be made, for example, of tris(2,4-di-tert-butylphenyl)phosphite available from BASF under the name RGAFOS 168, tris[2-[[2,4,8,10-tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphepin-6-yl]oxy]ethyl]amine available from BASF under the name IRGAFOS 12, bis(2,4-di-tert-butyl-6-methylphenyl)ethylphosphite available from BASF under the name IRGAFOS 38, and biphenyl-4,4′-diyl-bis[bis(2,4-di-tert-butyl-5-methylphenoxy)phosphine] available from Osaki Kogyosha under the name GSY-P1O1, as well as combinations thereof.

[0102] As lactone antioxidants, mention may be made, for example, of the reaction product of 3-hydroxy-5,7-di-tert-butyl-furan-2-one with o-xylene (CAS number 181314-48-7).

[0103] Examples of hydroxylamine-based antioxidants include oxidation products of alkylamines made from reduced beef tallow.

[0104] As an example of a vitamin E antioxidant, mention may be made of 3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol.

[0105] As sulfur-based antioxidants, mention may be made, for example, of didodecyl 3,3-thiobispropionate available from BASF under the name IRGANOX PS800, and dioctadecyl 3,3-thiobispropionate available from BASF under the name IRGANOX PS802.

[0106] In one preferred embodiment of the present invention, the antioxidant is selected from hindered phenol type antioxidants. In another preferred embodiment of the present invention, the hindered phenol type antioxidant may be represented by the following formula (I):

[0107] [ka]

[0108] During the ceremony, R 1 and R 3 each independently represents a linear or branched, saturated or unsaturated alkyl group having preferably 4 or more carbon atoms, more preferably 5 to 16 carbon atoms, and even more preferably 6 to 12 carbon atoms, which may be interrupted by at least one heteroatom such as O, S, or N; R 2 represents an alkyl group, preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group.

[0109] In the general formula (II), R 1 and R 3 Preferably, R in formula (II) represents a linear saturated alkyl group. 1 and R 3 represents an alkyl group interrupted by at least one carbonyl group (-O-C-), a carbonyloxy group (-O-C-O-) and / or a sulfur atom (-S-).

[0110] In one particular embodiment of the present invention, the (d-2) antioxidant is a hindered phenol type antioxidant containing at least two thioester groups, i.e. a thioester antioxidant such as, for example, 2,4-bis[(octylthio)methyl)-o-cresol, available from BASF under the name IRGANOX 1520L.

[0111] Other examples of the (d-2) antioxidant include the following commonly used antioxidants: phenols such as 4-methoxyphenol, 4-tert-butylcatechol, or 2,6-di-tert-butyl-4-methylphenol (BHT); hydroquinones such as 1,4-dihydroxybenzene or 3,5-di-tert-butylbenzene-1,2-diol; quinones such as 1,4-benzoquinone or naphthalene-1,2-dione; aromatic nitro compounds such as 1,3-dinitrobenzene or 1,4-dinitrobenzene; nitrophenols such as 2-(sec-butyl)-4,6-dinitrophenol, 4-methyl-2-nitrophenol, or 4-methyl-2,6-dinitrophenol; phenothiazine, N 1 -Phenyl-N 4 amines such as N-propylbenzene-1,4-diamine, N-(1,4-dimethylpentyl)-N'-phenyl-p-phenylenediamine, N,N-diethylhydroxylamine, or 2,2,6,6-tetramethylpiperidine; nitroso compounds such as N-nitrosophenylhydroxylamine ammonium salt; nitroxide compounds such as bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)sebacate, 1-oxyl-2,2,6,6-tetramethylpiperidine, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-ol, 1-oxyl-2,2,6,6-tetramethyl-4-n-butoxypiperidine; and mixtures thereof.

[0112] The (d-2) antioxidant may be contained in an amount of 0.001 mass% or more, preferably 0.005 mass% or more, more preferably 0.01 mass% or more, and particularly preferably 0.02 mass% or more, based on the total mass of the composition, and may be contained in an amount of 5 mass% or less, preferably 3 mass% or less, more preferably 2 mass% or less, and even more preferably 1 mass% or less.

[0113] In one embodiment of the present invention, the (D) photopolymerization inhibitor and / or antioxidant is selected from the (d-2) antioxidants, i.e., in one embodiment of the present invention, the photocurable silicone composition contains at least one (d-2) antioxidant.

[0114] In one embodiment of the present invention, the (d-2) antioxidant may include a phenolic antioxidant such as 2,6-di-tert-butyl-4-methylphenol (BHT).

[0115] (E) Other alkenyl-containing organopolysiloxanes The photocurable silicone composition according to the present invention may contain, as an optional component (E), an alkenyl-containing organopolysiloxane different from component (B). The photocurable silicone composition according to the present invention may contain one type of (E) alkenyl-containing organopolysiloxane, or may contain two or more types of (E) alkenyl-containing organopolysiloxanes.

[0116] Examples of the molecular structure of the alkenyl-containing organopolysiloxane of component (E) include linear, partially branched linear, branched, resin-like, and three-dimensional network structures.

[0117] Examples of the alkenyl group contained in component (E) include alkenyl groups having 2 to 12 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl groups, with vinyl groups being preferred.

[0118] Examples of groups other than alkenyl groups that are contained in component (E) and that are bonded to silicon atoms include halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups. Examples include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, phenethyl, and phenylpropyl; epoxy group-containing organic groups; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms, such as fluorine, chlorine, or bromine atoms.

[0119] Examples of epoxy group-containing organic groups include glycidoxyalkyl groups such as a 2-glycidoxyethyl group, a 3-glycidoxypropyl group, and a 4-glycidoxybutyl group; epoxycycloalkylalkyl groups such as a 2-(3,4-epoxycyclohexyl)-ethyl group and a 3-(3,4-epoxycyclohexyl)-propyl group; and epoxyalkyl groups such as a 3,4-epoxybutyl group and a 7,8-epoxyoctyl group. Of these, preferred is a glycidoxyalkyl group, and particularly preferred is a 3-glycidoxypropyl group.

[0120] Silicon atoms in component (E) may contain small amounts of hydroxyl groups or alkoxy groups such as methoxy groups and ethoxy groups, provided this does not impair the object of the present invention.

[0121] The group bonded to a silicon atom other than an alkenyl group in component (E) is preferably selected from an alkyl group having 1 to 6 carbon atoms, particularly a methyl group, an aryl group having 6 to 20 carbon atoms, particularly a phenyl group, or an epoxy group-containing organic group, particularly a 3-glycidoxypropyl group.

[0122] In a preferred embodiment of the present invention, the alkenyl group-containing organopolysiloxane of component (E) has at least one aryl group having 6 to 20 carbon atoms, particularly a phenyl group, from the standpoint of compatibility with the resin-like thiol group-containing organopolysiloxane of component (A).

[0123] In one embodiment of the present invention, component (E) may contain a resin-like alkenyl group-containing organopolysiloxane as component (E-1). The resin-like alkenyl group-containing organopolysiloxane (E-1) is preferably Average unit formula (III-a): (R 4 3SiO 1 / 2 ) a (R 4 2SiO 2 / 2 ) b (R 4 SiO 3 / 2 ) c (SiO 4 / 2 ) d (XO 1 / 2 ) e (In formula (III-a), R 4 are the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups, provided that at least two R 4 is an alkenyl group, 0≦a<1, 0≦b<1, 0≦c<0.9, 0≦d<0.5, and 0≦e<0.4, a+b+c+d=1.0, and c+d>0.

[0124] R in the above formula (III-a) 4 Examples of the halogen-substituted or unsubstituted monovalent hydrocarbon group include C groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups. 1~12 Alkyl groups: C such as phenyl, tolyl, xylyl, and naphthyl groups 6~12 Aryl groups; C such as benzyl, phenethyl and phenylpropyl groups 7~12Aralkyl groups: vinyl groups, allyl groups, butenyl groups, pentenyl groups, hexenyl groups, heptenyl groups, octenyl groups, nonenyl groups, decenyl groups, undecenyl groups, dodecenyl groups, etc. 2~12 alkenyl groups; groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine atoms, chlorine atoms, or bromine atoms, and preferably 1~12 Alkyl groups, especially methyl groups, C 2~12 Alkenyl groups, especially vinyl groups, C 6~12 It is selected from aryl groups, in particular phenyl groups.

[0125] In the above formula (III-a), X is a hydrogen atom or an alkyl group. The alkyl group for X is preferably an alkyl group having 1 to 3 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, and a propyl group.

[0126] In the above formula (III-a), a is preferably in the range of 0.05≦a≦0.6, more preferably in the range of 0.1≦a≦0.5, and even more preferably in the range of 0.1≦a≦0.4. In the above formula (III-a), b is preferably in the range of 0≦b≦0.6, more preferably in the range of 0≦b≦0.5, and particularly in the range of 0≦b≦0.4. In the above formula (III-a), c is preferably in the range of 0.2≦c<0.9, more preferably in the range of 0.3≦c≦0.85, and particularly in the range of 0.4≦c≦0.8. In the above formula (III-a), d is preferably in the range of 0≦d≦0.4, more preferably in the range of 0≦d≦0.25, and particularly in the range of 0≦d≦0.1. In the above formula (III-a), e is preferably in the range of 0≦e≦0.15, more preferably in the range of 0≦e≦0.1, and particularly in the range of 0≦e≦0.05. In addition, in formula (III-a), c+d is preferably in the range of 0.1≦c+d≦0.9, more preferably in the range of 0.2≦c+d≦0.85, and particularly preferably in the range of 0.3≦c+d≦0.8.

[0127] In a preferred embodiment of the present invention, the resin-like alkenyl group-containing organopolysiloxane of component (E-1) is a compound represented by the above formula (III-a), in which c is greater than 0, i.e., R—SiO 3 / 2 The resin-like organopolysiloxane of component (E-1) contains siloxane units (T units) represented by the formula: SiO 4 / 2 It may or may not contain a siloxane unit (Q unit) represented by the following formula: but preferably it does not contain one.

[0128] In a preferred embodiment of the present invention, the resin-like alkenyl-containing organopolysiloxane of component (E-1) contains an alkenyl group at the molecular end. The resin-like organopolysiloxane of component (E-1) is preferably R-SiO 1 / 2 The siloxane unit (M unit) represented by the formula: 2 / 2 Siloxane units (D units) represented by the formula: 3 / 2 The siloxane unit (T unit) represented by the following formula (I) may or may not contain an alkenyl group, but preferably does not contain an alkenyl group.

[0129] In a preferred embodiment of the present invention, the resin-like alkenyl-containing organopolysiloxane of component (E-1) contains an aryl group in the silicon-bonded organic group. That is, in the above formula (III-a), at least one R 4 may be an aryl group. In a preferred embodiment of the present invention, the resin-like alkenyl-containing organopolysiloxane of component (E-1) contains silicon-bonded aryl groups in the molecular side chains, i.e., in the D units and / or T units, and particularly preferably contains silicon-bonded aryl groups only in the T units. The resin-like alkenyl-containing organopolysiloxane of component (E-1) may or may not contain aryl groups in the molecular terminals, i.e., in the M units, but preferably does not. Examples of the aryl group include aryl groups having 6 to 20 carbon atoms, particularly phenyl, tolyl, xylyl, and naphthyl groups.

[0130] When the resin-like organopolysiloxane of component (E-1) contains an aryl group, its content (mol% of aryl groups in the total silicon-bonded functional groups of the resin-like organopolysiloxane) can be designed as desired, but is usually 5 mol% or more, preferably 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, particularly preferably 25 mol% or more, and is usually 70 mol% or less, preferably 60 mol% or less, more preferably 55 mol% or less. The content of aryl groups can be determined, for example, by analysis using a Fourier transform infrared spectrophotometer (FT-IR), nuclear magnetic resonance (NMR), etc.

[0131] A specific example of the resinous organopolysiloxane of the component (E-1) is MDT resin, which is a resinous organopolysiloxane composed of M units, D units, and T units.

[0132] In one embodiment, the resinous organopolysiloxane of component (E-1) is liquid at room temperature.

[0133] The mass average molecular weight (Mw) of the component (E-1) is not particularly limited, but is, for example, from 500 to 10,000, and preferably from 1,000 to 5,000. In this specification, the mass average molecular weight can be measured, for example, by GPC.

[0134] A specific example of the MDT resin of component (E-1) is, for example, the average structural formula: (Vi(Me3)2SiO 1 / 2 ) 15 ((Me3)2SiO 2 / 2 ) 35 (PhSiO 3 / 2 ) 50 Here, Vi represents a vinyl group, Me represents a methyl group, and Ph represents a phenyl group.

[0135] The component (E) may contain one or more types of linear alkenyl group-containing organopolysiloxane as the component (E-2). The linear alkenyl group-containing organopolysiloxane of the component (E-2) is preferably Average structural formula (III-b):R 4 3SiO(R 4 2SiO 2 / 2 ) m SiR 4 3 (In formula (III-b), R 4 are the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups, provided that at least two R 4 is an alkenyl group, and m is 1 to 500.

[0136] In the above formula (III-b), R 4 The halogen-substituted or unsubstituted monovalent hydrocarbon group may be the same as that in the above formula (III-a).

[0137] In the above formula (III-b), m is preferably 2-300, and more preferably 5-150.

[0138] Examples of such component (E-2) include dimethylpolysiloxanes capped with dimethylvinylsiloxy groups at both molecular chain terminals, dimethylpolysiloxanes capped with diphenylvinylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylphenylsiloxane copolymers capped with dimethylvinylsiloxy groups at both molecular chain terminals, dimethylsiloxane-diphenylsiloxane copolymers capped with dimethylvinylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylphenylsiloxane copolymers capped with diphenylvinylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylvinylsiloxane copolymers capped with dimethylvinylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylvinylsiloxane copolymers capped with dimethylvinylsiloxy groups at both molecular chain terminals, Examples of such compounds include dimethylsiloxane-methylphenylsiloxane-methylvinylsiloxane copolymers capped with dimethylvinylsiloxane-diphenylsiloxane-methylvinylsiloxane copolymers capped with dimethylvinylsiloxane-terminated at both molecular chain ends with dimethylvinylsiloxane-terminated at both molecular chain ends with trimethylsiloxy groups, methylvinylpolysiloxanes capped with trimethylsiloxy groups at both molecular chain ends with methylvinylsiloxane-methylphenylsiloxane copolymers capped with trimethylsiloxy groups at both molecular chain ends, methylvinylsiloxane-diphenylsiloxane copolymers capped with trimethylsiloxy groups at both molecular chain ends, and dimethylsiloxane-methylvinylsiloxane copolymers capped with trimethylsiloxy groups at both molecular chain ends.

[0139] In a preferred embodiment of the present invention, the linear alkenyl-containing organopolysiloxane of component (E-2) may be a linear organopolysiloxane capped with alkenyl groups at both molecular chain terminals, which contains alkenyl groups at both molecular chain terminals. The linear organopolysiloxane of component (E-2) may or may not contain alkenyl groups in the molecular chain side chains (i.e., D units), but preferably does not contain them.

[0140] In one embodiment of the present invention, the linear organopolysiloxane of component (E-2) contains an aryl group in the silicon-bonded organic group. That is, in the above formula (III-b), at least one R 4may be an aryl group. In a preferred embodiment of the present invention, the linear alkenyl-containing organopolysiloxane of component (E-2) contains a silicon-bonded aryl group in a molecular side chain. The linear organopolysiloxane of component (E-2) may or may not contain an aryl group at the molecular chain end (i.e., M unit), but preferably does not.

[0141] When the linear organopolysiloxane of component (E-2) contains an aryl group, its content (mol % of aryl groups in the total silicon-bonded functional groups of the linear organopolysiloxane) can be designed as desired, but is usually 15 mol % or more, preferably 20 mol % or more, more preferably 25 mol % or more, and may be 70 mol % or less, preferably 60 mol % or less, more preferably 55 mol % or less. The aryl group content can be determined, for example, by analysis using a Fourier transform infrared spectrophotometer (FT-IR), nuclear magnetic resonance (NMR), etc.

[0142] Component (E) may contain one or more epoxy group-containing organopolysiloxanes as component (E-3). Examples of the molecular structure of the epoxy group-containing organopolysiloxane include linear, partially branched linear, branched, resinous, cyclic, and three-dimensional network structures, and epoxy group-containing resinous organopolysiloxanes are preferred.

[0143] The epoxy group-containing resinous organopolysiloxane preferably has the following average unit formula (III-c): (R 5 3SiO 1 / 2 ) f (R 5 2SiO 2 / 2 ) g (R 5 SiO 3 / 2 ) h (SiO 4 / 2 ) i (XO 1 / 2 ) j {In formula (III-c), R 5are each independently a halogen-substituted or unsubstituted monovalent hydrocarbon group, provided that at least two R 5 is an alkenyl group, and at least one R 5 is an epoxy group-containing organic group, X is a hydrogen atom or an alkyl group, 0≦f<1, 0≦g<1, 0≦h<0.9, 0≦i<0.5, and 0≦j<0.5, and f+g+h+i+j=1.0, h+i>0. j means the number of (XO) groups when the total number of silicon atoms is 1 (representing the ratio of the number of (XO) groups to the total number of silicon atoms).}

[0144] In the above (III-c), R 5 Examples of the halogen-substituted or unsubstituted monovalent hydrocarbon group include C aryl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups. 1~12 Alkyl groups: C such as phenyl, tolyl, xylyl, and naphthyl groups 6~12 Aryl groups; C such as benzyl, phenethyl and phenylpropyl groups 7~12 Aralkyl groups: vinyl groups, allyl groups, butenyl groups, pentenyl groups, hexenyl groups, heptenyl groups, octenyl groups, nonenyl groups, decenyl groups, undecenyl groups, dodecenyl groups, etc. 2~12 Examples of the epoxy group-containing organic group include an alkenyl group, an epoxy group-containing organic group, and a group in which some or all of the hydrogen atoms of the above groups have been substituted with halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms. The epoxy group-containing organic group is as described above. R 5 is preferably selected from an alkyl group having 1 to 6 carbon atoms, particularly a methyl group, an alkenyl group having 2 to 6 carbon atoms, particularly a vinyl group, an aryl group having 6 to 20 carbon atoms, particularly a phenyl group, and a 3-glycidoxypropyl group.

[0145] In the above formula (III-c), X is a hydrogen atom or an alkyl group. The alkyl group for X is preferably an alkyl group having 1 to 3 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, and a propyl group.

[0146] In the above formula (III-c), based on f+g+h+i+j=1.0, f is preferably in the range of 0.03≦f≦0.7, more preferably in the range of 0.06≦f≦0.5, and even more preferably in the range of 0.09≦f≦0.3. In the above formula (III-c), g is preferably in the range of 0.05≦g≦0.6, more preferably in the range of 0.1≦g≦0.4, and particularly in the range of 0.2≦g≦0.3. In the above formula (III-c), h is preferably in the range of 0.1≦h≦0.8, more preferably in the range of 0.25≦h≦0.7, and particularly in the range of 0.4≦h≦0.6. In the above formula (III-c), i is preferably in the range of 0≦i≦0.4, more preferably in the range of 0≦i≦0.25, and particularly in the range of 0≦i≦0.1. In the above formula (III-c), j is preferably in the range of 0.05≦j≦0.4, more preferably in the range of 0.1≦j≦0.3, and particularly in the range of 0.15≦j≦0.25. In addition, in the formula (III-c), h+i is preferably in the range of 0.1≦h+i≦0.9, more preferably in the range of 0.2≦h+i≦0.8, and particularly in the range of 0.3≦h+i≦0.7.

[0147] In a preferred embodiment of the present invention, the epoxy group-containing resinous organopolysiloxane is represented by the above formula (III-c), where h is greater than 0, i.e., R—SiO 3 / 2 The epoxy group-containing resin-like organopolysiloxane of component (E-3) contains siloxane units (T units) represented by the following formula: SiO 4 / 2 It may or may not contain a siloxane unit (Q unit) represented by the following formula: but preferably it does not contain one.

[0148] In a preferred embodiment of the present invention, the epoxy group-containing organopolysiloxane (E-3) contains an alkenyl group at the molecular end. The epoxy group-containing organopolysiloxane is preferably R3-SiO 1 / 2 The siloxane unit (M unit) represented by the formula: 2 / 2 Siloxane units (D units) represented by the formula: 3 / 2 The siloxane unit (T unit) represented by the following formula (I) may or may not contain an alkenyl group, but preferably does not contain an alkenyl group.

[0149] In a preferred embodiment of the present invention, the epoxy group-containing resinous organopolysiloxane (E-3) contains an aryl group in the silicon atom-bonded organic group. 5 At least one of the above may be an aryl group. In a preferred embodiment of the present invention, the epoxy group-containing resinous organopolysiloxane contains a silicon atom-bonded aryl group in the molecular side chain, i.e., in the D unit or T unit, preferably in the T unit. The epoxy group-containing resinous organopolysiloxane may or may not contain an aryl group in the molecular end, i.e., in the M unit, but preferably does not contain one. The aryl group may be an aryl group having 6 to 20 carbon atoms, particularly a phenyl group, a tolyl group, a xylyl group, or a naphthyl group.

[0150] When the epoxy group-containing organopolysiloxane (E-3) contains aryl groups, the content thereof (the mole % of aryl groups based on all silicon-bonded functional groups in the epoxy group-containing organopolysiloxane) can be designed as desired, but is preferably 15 mol % or more, more preferably 20 mol % or more, even more preferably 25 mol % or more, and particularly preferably 30 mol % or more, and is preferably 70 mol % or less, more preferably 60 mol % or less, even more preferably 50 mol % or less, and particularly preferably 40 mol % or less.

[0151] The amount of epoxy-containing organic groups in the total silicon-bonded organic groups in the epoxy-containing organopolysiloxane (E-3) is not particularly limited, but is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, particularly preferably 15 mol% or more, and is, for example, 40 mol% or less, preferably 30 mol% or less, more preferably 25 mol% or less. The amount of epoxy-containing organic groups can be determined, for example, by analysis using a Fourier transform infrared spectrophotometer (FT-IR), nuclear magnetic resonance (NMR), etc.

[0152] In a preferred embodiment of the present invention, the epoxy group-containing organopolysiloxane contains hydroxyl groups and / or alkoxy groups as silicon atom-bonded organic groups. The amount of hydroxyl groups and / or alkoxy groups in the total silicon atom-bonded organic groups in the epoxy group-containing organopolysiloxane is not particularly limited, but is preferably 2 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, and is, for example, 30 mol% or less, preferably 20 mol% or less, more preferably 15 mol% or less. The amount of hydroxyl groups and / or alkoxy groups can be determined, for example, by analysis using a Fourier transform infrared spectrophotometer (FT-IR), nuclear magnetic resonance (NMR), etc.

[0153] The content of alkenyl groups in the total silicon-bonded organic groups of the alkenyl-containing organopolysiloxane of component (E) is not particularly limited, but may be, for example, 1 mol% or more of the total silicon-bonded organic groups, and 40 mol% or less of the total silicon-bonded organic groups. The content of alkenyl groups can be determined, for example, by analytical methods such as Fourier transform infrared spectrophotometer (FT-IR) and nuclear magnetic resonance (NMR), or by the titration method described above.

[0154] There are no particular limitations on the number average molecular weight of the organopolysiloxane of the component (E-1), but it can be within the range of 850 to 10,000.

[0155] In one embodiment of the present invention, the ratio of thiol groups to alkenyl groups (SH / Ar) contained in the organosilicon compound contained in the photocurable silicone resin of the present invention is not particularly limited, but preferably, the number of thiol groups per mole of alkenyl groups is 0.2 or more, more preferably 0.3 or more, and even more preferably 0.4 or more; and, for example, the number of thiol groups per mole of alkenyl groups can be 5 or less, preferably 3 or less, more preferably 2 or less, even more preferably 1.5 or less, and preferentially 1.2 or less.

[0156] (F) Inorganic filler The photocurable silicone composition according to the present invention may contain one or more inorganic fillers as the optional component (F). The inorganic filler may be selected from inorganic fillers such as ground quartz, silica, titanium oxide, magnesium carbonate, zinc oxide, iron oxide, diatomaceous earth, and inorganic fillers obtained by subjecting the surface of such inorganic fillers to a hydrophobic treatment with an organosilicon compound.

[0157] The inorganic filler of component (F) is preferably selected from silica. Examples of silica include fumed silica, wet silica, crystalline silica, precipitated silica, etc. In addition, the silica may be surface-hydrophobized with an organosilicon compound such as an organoalkoxysilane compound, an organochlorosilane compound, an organosilazane compound, or a low-molecular-weight siloxane compound, or a silane coupling agent, a titanate coupling agent, etc.

[0158] There are no particular limitations on the amount of component (F) blended, but it is preferably contained in the photocurable silicone composition of the present invention in an amount of at least 0.01 mass %, more preferably at least 0.1 mass %, preferentially at least 1 mass %, and especially at least 3 mass %, based on the total mass of the composition, and is preferably contained in the photocurable silicone composition of the present invention in an amount of no more than 20 mass %, more preferably no more than 15 mass %, and preferentially no more than 10 mass %.

[0159] (Optional Additives) The photocurable silicone composition of the present invention may contain any additive commonly used in the field of the present invention, such as organic fillers, pigments, tackifiers, resistance agents, release agents, heat resistance agents, colorants, flame retardants, and combinations thereof.

[0160] The curable silicone composition according to the present invention is photocurable, and specifically, can be cured by irradiation with active energy rays (e.g., ultraviolet rays). Therefore, in one embodiment of the present invention, the photocurable silicone composition according to the present invention is a UV-curable silicone composition. The wavelength of the ultraviolet light to be irradiated is not particularly limited, but is preferably in the range of 360 nm to 395 nm. The irradiation is 500 to 1500 J / cm. 2 For example, ultraviolet light (wavelength 365 nm, 1000 J / cm) from a metal halide lamp can be used. 2 The photocurable silicone composition can be cured by irradiating the composition with light. The irradiation time is not particularly limited, but is usually in the range of 1 to 60 seconds, preferably 5 to 30 seconds, and more preferably 10 to 20 seconds.

[0161] The photocurable silicone composition according to the present invention can be cured to form a cured product having good transparency. Specifically, the cured product of the curable silicone composition according to the present invention preferably has a light transmittance of 90% or more at wavelengths of 400 nm to 700 nm, measured using a sample having a thickness of 1 mm. The light transmittance of the cured product of the curable silicone composition can be determined, for example, by measuring a cured product having an optical path length of 1 using a spectrophotometer.

[0162] The photocurable silicone composition of the present invention can be cured to form a cured product with high hardness. The cured product obtained by curing the photocurable silicone composition of the present invention preferably has a Type A durometer hardness of A50 or more at 25° C. The Type A durometer hardness is determined using a Type A durometer in accordance with JIS K 6253-1997.

[0163] There are no particular limitations on the viscosity of the photocurable silicone composition according to the present invention, but it is preferably in the range of 15 mPa·s to 20,000 mPa·s at 25° C. The viscosity can be measured, for example, using a B-type rotational viscometer (MCR-302, manufactured by Anton Paar) in accordance with the method described in JIS K 7117-1:1999.

[0164] There are no particular limitations on the refractive index of the photocurable silicone composition according to the present invention, but for example, the refractive index at 25°C and 589 nm, as measured with an Abbe refractometer, is preferably greater than 1.4, more preferably 1.43 or greater, and typically 1.52 or less.

[0165] The photocurable silicone composition according to the present invention preferably has a long pot life.For example, in a preferred embodiment of the present invention, even if the photocurable silicone composition is kept at 25°C in a bright room environment for 24 hours, the increase in viscosity may be less than 10%.The viscosity is measured as described above.

[0166] The photocurable silicone composition according to the present invention can be prepared by mixing the above-mentioned essential components and optional components by a conventional method.The mixing method of each component can be a conventionally known method and is not particularly limited.For example, mixing can be performed by simple stirring, or using a mixing device such as a single-screw or double-screw continuous mixer, a double roll, a Hobart mixer, a dental mixer, a planetary mixer, a kneader mixer, and a Henschel mixer.

[0167] [Sealing materials and sheet films] The present invention also relates to an encapsulant or sheet film obtained by curing the photocurable silicone composition according to the present invention. The encapsulant of the present invention is preferably used to encapsulate optical semiconductor elements including optical semiconductors. The sheet film of the present invention is preferably used as an encapsulant layer or a pressure-sensitive adhesive sheet film for mass transfer.

[0168] Examples of semiconductor elements include SiC, GaN, etc. Examples of optical semiconductor elements include semiconductor elements such as light-emitting diodes (LEDs), photodiodes, phototransistors, and laser diodes.

[0169] The sealing material or sheet film of the present invention can be obtained, for example, by applying the photocurable silicone composition of the present invention to a film-, tape-, or sheet-shaped substrate, and then curing the composition by irradiating it with active energy rays (e.g., ultraviolet rays) to form a cured film on the surface of the substrate. The thickness of the cured film is not particularly limited, but is preferably within the range of 1 μm to 10 mm, or within the range of 5 μm to 5 mm.

[0170] The present invention includes the following aspects. Aspect 1: (A) At least two thiol groups and at least one SiO 4 / 2 or R-SiO 3 / 2 A resin-like thiol group-containing organopolysiloxane containing a siloxane unit represented by the formula: (B) a silicone reactive diluent selected from organosilane compounds containing at least two alkenyl groups per molecule, cyclic organopolysiloxanes containing at least two alkenyl groups per molecule, organopolysiloxane compounds consisting of M and Q units containing at least two alkenyl groups per molecule, and mixtures thereof; (C) at least one photoinitiator; and (D) at least one polymerization inhibitor and / or antioxidant; 1. A photocurable silicone composition comprising: Aspect 2: The composition according to aspect 1, wherein (A) the resinous thiol group-containing organopolysiloxane has thiol groups as pendant groups and does not have thiol groups at the ends of the polymer chains. Aspect 3: (A) The resin-like thiol group-containing organopolysiloxane is R2-SiO 2 / 2 3. The composition of claim 1 or 2, wherein the composition does not include a siloxane unit represented by the formula: Aspect 4: The composition of any of Aspects 1-3, wherein (B) the silicone reactive diluent has a number average molecular weight of less than 800. Aspect 5: The composition according to any one of Aspects 1 to 4, wherein the (C) photopolymerization initiator includes an alkylphenone-type photopolymerization initiator. Aspect 6: The composition according to any one of Aspects 1 to 5, wherein (D) the polymerization inhibitor and / or antioxidant is selected from (d-2) antioxidants. Aspect 7: The composition of aspect 6, wherein (d-2) the antioxidant comprises 2,6-di-tert-butyl-4-methylphenol (BHT). Embodiment 8: The composition of any one of embodiments 1-7, wherein (B) the silicone reactive diluent is present in an amount greater than 2% by weight, based on the total weight of the photocurable silicone composition. Aspect 9: An encapsulant or sheet film formed from the photocurable silicone composition according to any one of aspects 1 to 8. EXAMPLES

[0171] The present invention is described in more detail in the following examples, which should not be construed as limiting the scope of the invention.

[0172] The photocurable silicone composition of the present invention will be described in detail with reference to examples and comparative examples. In the examples and comparative examples, the following components were used to prepare the photocurable silicone composition. In the recipe, Vi represents a vinyl group, Me represents a methyl group, Ph represents a phenyl group, Ep represents an epoxy group-containing organic group, and SH represents a thiol group (HSCH2CH2CH2- group). The numerical values ​​representing the amounts in the table are based on the "parts by mass" of the active ingredients of the raw materials. The structure of the organopolysiloxane component is shown in a simplified form in the table, and the functional groups other than Me in the M, D, or T units are shown in parentheses. SH / Vi represents the molar ratio of silicon-bonded thiol groups (SH) to vinyl groups (Vi) in the organopolysiloxane component.

[0173] (component) (a) Average unit formula (Me3SiO 1 / 2 ) 43.5(SHSiO 3 / 2 ) 43 (SiO 4 / 2 ) 13.5 At least two thiol groups and at least one SiO 4 / 2 A resin-like thiol group-containing organopolysiloxane containing a siloxane unit represented by the formula: (a'-1) Trimethylolpropane tris(3-mercaptobutyrate) (TPMB) (a'-2) [(Mercaptopropyl)methylsiloxane]-dimethylsiloxane copolymer (product name: SMS-142, manufactured by Gelest) (a'-3) Average structural formula Me3SiO(MeSHSiO 2 / 2 ) 17.2 Linear thiol group-containing organopolysiloxane represented by SiMe3 (a'-4) 1,2-bis(2-mercaptoethoxy)ethane, 3,6-dioxa-1,8-octane-dithiol (DMDO) (b-1) Dimethyldivinylsilane (b-2) Alkenyl-containing organopolysiloxane compound represented by the formula (Me2ViSiO)4Si (b-3) Formula (MeViSiO 2 / 2 ) Cyclic alkenyl group-containing organopolysiloxane represented by 4 (c) 2-Hydroxy-2-methyl-1-phenyl-1-propanone (product name: Omnirad 1173, manufactured by IGM RESINS BV) (d-1) Propoxylated glycerol (1PO / OH) triacrylate (product name: Genorad 16, manufactured by Rahn) (d-2) 2,6-di-tert-butyl-4-methylphenol (BHT) (e-1) Average structural formula ViMe2SiO(Me2SiO 2 / 2 )9SiMe2Vi is a linear alkenyl-containing organopolysiloxane. (e-2) Average unit formula (Me3SiO 1 / 2 )5(ViMe2SiO 1 / 2 ) 17 (MeSiO 3 / 2) 39 (PhSiO 3 / 2 ) 39 Resin-like alkenyl-containing organopolysiloxane represented by the formula: Mw: 2,700 (e-3) Average structural formula ViMe2SiO(Ph2SiO) 20 Linear alkenyl-containing organopolysiloxane represented by SiMe2Vi (e-4) Average unit formula (ViMe2SiO 1 / 2 ) 25 (PhSiO 3 / 2 ) 75 Resin-like alkenyl-containing organopolysiloxane represented by the formula: Mw: 2,300 (e-5) Average structural formula ViMe2SiO(Ph2SiO) 20 Linear alkenyl-containing organopolysiloxane represented by SiMe2Vi (e-6) Average unit formula (ViMe2SiO 1 / 2 ) 13 (EpMeSiO 2 / 2 ) 24 (PhSiO 3 / 2 ) 46 (OMe) 17 Epoxy group-containing resin-like organopolysiloxane represented by the formula: Mw; 3,400 (e-7) Average unit formula (Me3SiO 1 / 2 ) 14 (ViMe2SiO 1 / 2 ) 11 (MeSiO 3 / 2 ) 53 (PhSiO 3 / 2 ) 22 Resin-like alkenyl-containing organopolysiloxane represented by the formula: Mw: 5,000 (e-8) Average structural formula ViMe2SiO(Me2SiO) 60 (Ph2SiO) 30 Linear alkenyl-containing organopolysiloxane represented by SiMe2Vi (e-9) Average unit formula (ViMe2SiO 1 / 2 ) 15 (MeSiO 2 / 2 ) 30 (PhSiO 3 / 2 )50 Resin-like alkenyl-containing organopolysiloxane represented by the formula: Mw: 2,700 (f) Fumed Silica

[0174] [evaluation] (hardness) The resulting photocurable silicone composition was irradiated with ultraviolet light of 365 nm using a metal halide lamp at a cumulative irradiation dose of 200 mW / cm 2 Using the obtained cured sample, the hardness at 25°C was measured using a Durometer A hardness tester or a Durometer D hardness tester in accordance with JIS K 6253-1997.

[0175] (light transmittance) The photocurable silicone composition was poured into a mold having a recess of a given shape, and ultraviolet light with a wavelength of 365 nm was irradiated from above the liquid surface using a metal halide lamp at a cumulative irradiation dose of 200 mW / cm. 2 The photocurable silicone composition was cured by irradiating the material with ultraviolet light so that the ultraviolet light irradiation time was 15 seconds. The light transmittance of the obtained plate-like cured product was measured at 25°C and 450 nm. In Examples 1 to 6 and Comparative Examples 1 and 2, the light transmittance was measured using a sample having a thickness of 1 mm, and in Examples 7 to 12 and Comparative Examples 3 to 6, the light transmittance was measured using a sample having a thickness of 2 mm.

[0176] (Change in light transmittance after heating) The samples whose light transmittance was measured were heated at 260°C for 10 minutes, and the transmittance was measured at 25°C and 450 nm. Samples whose light transmittance changed by 10% or less after heating were marked "OK", and samples whose light transmittance changed by more than 10% after heating were marked "NG".

[0177] (viscosity) The viscosity of the resulting photocurable silicone composition at 25° C. was measured using a Brookfield type rotational viscometer (MCR-302, manufactured by Anton Paar) in accordance with the method described in JIS K 7117-1:1999.

[0178] (Pot Life) The photocurable silicone compositions obtained were stored for 24 hours at 25° C. in a bright room environment, and those that showed an increase in viscosity of less than 10% were rated "OK."

[0179] (Refractive Index) The refractive index of the resulting photocurable silicone composition at 25° C. and 589 nm was measured using an Abbe refractometer.

[0180] (Die shear strength) The obtained photocurable composition was uniformly applied to a glass plate. Next, another glass plate was laminated on the composition, and the composition was exposed to UV irradiation (365 nm, 200 mW / cm2) from a metal halide lamp. 2 ) to obtain a sheet having a thickness of 1 mm. The die shear strength was measured using a die shear tester (Nordson DAGE DAGE4000 Bond Tester). Samples with a die shear strength of 2 MPa or more were evaluated as "OK".

[0181] The results are shown in the table below.

[0182] [Table 1]

[0183] [Table 2]

[0184] [Table 3]

[0185] As can be seen from the results in Tables 1 to 3, the cured products obtained from the photocurable silicone composition according to the present invention were excellent in hardness and transparency, and were able to maintain their excellent transparency even after heat treatment. Furthermore, the photocurable silicone compositions of Examples 7 to 12 of the present invention also had excellent pot life and cured product strength.

Claims

1. (A) At least two thiol groups and at least one SiO ４／２ (Q unit) or R-SiO ３／２ a resin-like thiol group-containing organopolysiloxane containing a siloxane unit (T unit) represented by the following formula (wherein R represents a monovalent organic group); (B) an organosilane compound containing at least two alkenyl groups per molecule, a cyclic organopolysiloxane containing at least two alkenyl groups per molecule, R ３ -SiO １／２ and mixtures thereof; (C) at least one photoinitiator; and (D) at least one polymerization inhibitor and / or antioxidant; 1. A photocurable silicone composition comprising:

2. 2. The composition according to claim 1, wherein (A) the resinous thiol group-containing organopolysiloxane has thiol groups as pendant groups and no thiol groups in the M units.

3. (A) The resin-like thiol group-containing organopolysiloxane is represented by R ２ -SiO ２／２ The composition according to claim 1 or 2, which does not contain a siloxane unit (D unit) represented by the following formula:

4. The composition of claim 1 , wherein (B) the silicone reactive diluent has a number average molecular weight of less than 800.

5. The composition of claim 1 , wherein the photoinitiator (C) comprises an alkylphenone type photoinitiator.

6. The composition according to claim 1, wherein the (D) polymerization inhibitor and / or antioxidant is selected from (d-2) antioxidants.

7. The composition of claim 6, wherein the antioxidant (d-2) comprises 2,6-di-tert-butyl-4-methylphenol (BHT).

8. 10. The composition of claim 1, wherein (B) the silicone reactive diluent is present in an amount greater than 2 weight percent, based on the total weight of the photocurable silicone composition.

9. A sealing material or sheet film formed from the photocurable silicone composition according to any one of claims 1 to 8.

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