Photocurable silicone compositions, sealants and sheet films

Abstract

This invention relates to a photocurable silicone composition comprising: (A) a resinous organopolysiloxane containing thiol groups, the organopolysiloxane containing at least two thiol groups / molecules and at least one SiO2 group. 4 / 2 (Q unit) or made of R-SiO 3 / 2 (where R represents a monovalent organic group) siloxane unit (T unit); and (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, and compounds containing at least two alkenyl groups per molecule and comprising R3-SiO 1 / 2 The organopolysiloxane compound represented by the siloxane unit (M unit) and the Q unit, and mixtures thereof.

Description

TECHNICAL FIELD

[0001] The present application relates to: a photocurable silicone composition; and a sealing material or sheet film formed from the photocurable silicone composition. This application claims priority based on patent application number 2023-185633 filed in Japan on October 30, 2023, and the content of this patent application is hereby incorporated. BACKGROUND

[0002] Curable silicone compositions form cured products having excellent heat resistance, cold resistance, electrical insulation properties, weather resistance, waterproofness, and transparency, and are therefore used in various industrial fields. The cured products of such curable silicone compositions are less likely to discolor than other organic materials, and physical properties are hardly deteriorated, and are therefore suitable for use as optical materials and sealing materials for semiconductor devices.

[0003] Among curable silicone compositions, photocurable silicone compositions can avoid problems such as shape shrinkage during molding and damage to electronic parts, which are caused by heating the curable silicone composition, and are therefore used in several types of products.

[0004] A mercapto-functional compound is sometimes blended in a photocurable silicone composition in order to cause the cured product to exhibit shape stability and the like. In the past, several applications of photocurable silicone compositions containing a mercapto-functional compound have been disclosed.

[0005] For example, Patent Literature 1 discloses a UV-curable silicone composition containing: A) an alkenyl-containing organopolysiloxane having at least two alkenyl groups in each molecule, having at least one alkenyl group on each terminal; 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, Patent Document 2 discloses a UV-curable silicone resin composition comprising: (A) a linear polyorganosiloxane containing aliphatic unsaturated groups; (B) a polyorganosiloxane having a viscosity of 10-10,000 cP at 23°C and containing mercaptoalkyl groups bonded to silicon atoms; (C) a photoreaction initiator based on acylphosphine oxide; and (D) a compound exhibiting compatibility with components (A) and (B), exhibiting compatibility with component (C), and having a boiling point of 200°C or higher, wherein the ratio of the number of mercaptoalkyl groups in component (B) to the number of aliphatic unsaturated groups in component (A) is 0.1-10, and in a total of 100 wt% of components (A) to (D), the amount of component (C) is 0.1-0.5 wt% and the amount of component (D) is 0.1-2.0 wt%.

[0007] Furthermore, Patent Document 3 discloses a photocurable liquid silicone composition comprising: (A) an organosilane or a low molecular weight organosiloxane having 1-5 carbon atoms and wherein each molecule has at least two alkenyl groups and at least two monovalent functional groups selected from aromatic groups and aralkyl groups; (C) a compound having at least two thiol groups in the molecule; and (D) a photoradical initiator, wherein the refractive index of the entire liquid composition is 1.48 or greater before curing.

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

[0009] However, photocurable silicone compositions containing thiol functional compounds exhibit excellent shape stability during curing, but in some cases have problems such as insufficient hardness. [Existing Technical Documents] [Patent Literature]

[0010] [Patent Document 1] International Publication No. WO 2018 / 223365 [Patent Document 2] Japanese Patent Application Publication No. 2013-253179 [Patent Document 3] International Publication No. WO 2021 / 167051 [Patent Document 4] Japanese Patent Application Publication No. 2022-19171 Summary of the Invention [The problem this invention aims to solve]

[0011] The purpose of this invention is to provide a photocurable silicone composition comprising at least one thiol-functionalized organopolysiloxane and capable of forming a cured product with excellent hardness and transparency. [Problem-solving methods]

[0012] The above-mentioned objectives of the present invention can be achieved through This is achieved through a photocurable silicone composition comprising: (A) a resinous organopolysiloxane containing thiol groups, the organopolysiloxane containing at least two thiol groups / molecules and at least one SiO2. 4 / 2 (Q unit) or made of R-SiO 3 / 2 (Where R refers to a monovalent organic group such as a monovalent hydrocarbon group. This also applies below.) represents a siloxane unit (T unit); (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, and compounds containing at least two alkenyl groups per molecule and comprising R3-SiO2. 1 / 2 The organopolysiloxane compound represented by the siloxane unit (M unit) and the Q unit, and mixtures thereof; (C) at least one photopolymerization initiator; and (D) At least one polymerization inhibitor and / or antioxidant.

[0013] The resin-like organopolysiloxane (A) containing thiol groups preferably has thiol groups as side groups and does not have thiol groups in the M unit.

[0014] The resinous organopolysiloxane (A) containing thiol groups preferably does not contain R2-SiO2. 2 / 2 The siloxane unit (D unit) is represented.

[0015] Silicone reactive diluents (B) can have a number-average molecular weight of less than 800.

[0016] Photopolymerization initiator (C) may contain alkyl phenyl ketone type photopolymerization initiator.

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

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

[0019] The silicone reactive diluent (B) may be contained in an amount exceeding 2% by mass based on the total mass of the photocurable silicone composition.

[0020] The present invention also relates to a sealing material or sheet film formed using the photocurable silicone composition of the present invention. [Invention Effects]

[0021] The photocurable silicone composition of the present invention comprises an organopolysiloxane containing thiol groups and can form a cured product with excellent hardness and transparency. In particular, the cured product of the present invention maintains good transparency even after heat treatment. Detailed Implementation

[0022] Through diligent research, the inventors of this invention unexpectedly discovered that a photocurable silicone composition containing an organopolysiloxane with a specific structure containing a thiol-containing group and a specified amount of a silicone reactive diluent containing at least two alkenyl groups per molecule can form a cured product with excellent hardness and transparency, thus completing this invention.

[0023] Therefore, the composition according to the present invention is a photocurable silicone composition comprising: (A) Contains at least two thiol groups / molecules and at least one component of SiO2. 4 / 2 or R-SiO 3 / 2 The resinous organopolysiloxane containing thiol groups, representing a siloxane unit; (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 containing at least two alkenyl groups per molecule and comprising M and Q units, and mixtures thereof. (C) at least one photopolymerization initiator; and (D) At least one polymerization inhibitor and / or antioxidant.

[0024] The compositions, sealing materials, and sheet films of the present invention will now be explained in more detail.

[0025] [Photocurable composition] The photocurable silicone composition of the present invention comprises: (A) containing at least two thiol groups / molecules and at least one component derived from SiO2. 4 / 2or R-SiO 3 / 2 The components are: (A) a resinous organopolysiloxane containing a thiol group representing a siloxane unit; (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 containing at least two alkenyl groups per molecule and comprising M and Q units, and mixtures thereof; (C) at least one photopolymerization initiator; and (D) at least one polymerization inhibitor and / or antioxidant. These components will now be explained in more detail.

[0026] (A) Contains at least two thiol groups / molecules and at least one component of SiO2. 4 / 2 or R-SiO 3 / 2 Resinous organopolysiloxanes containing thiol groups representing siloxane units. The photocurable silicone composition of the present invention contains at least one thiol group / molecule containing at least two thiol groups and at least one component of SiO2. 4 / 2 or R-SiO 3 / 2 The resinous organopolysiloxane containing thiol groups, representing the siloxane unit, is used as component (A). The photocurable silicone composition according to the invention may contain one type of organopolysiloxane containing thiol groups (A) or two or more types of organopolysiloxanes containing thiol groups (A).

[0027] The organopolysiloxane (A) containing thiol groups has a resinous molecular structure. In this specification, the term resinous means that the molecular structure has a branched or three-dimensional network structure. Specifically, the resinous organopolysiloxane containing thiol groups of component (A) comprises at least one component made of SiO₂. 4 / 2 The siloxane unit (also known as the "Q unit") or at least one of R-SiO 3 / 2 The term "siloxane unit" (also referred to as "T unit") is used. A thiol-containing organopolysiloxane (A) may contain Q units or T units, but may also contain both Q units and T units. In one embodiment, the term "resin-like" in this specification means an organopolysiloxane in which the total amount of T units and Q units is 5% or more, or 10% or more, relative to all siloxane units in a molecule. Furthermore, in this specification, resin-like organopolysiloxanes typically have a number-average molecular weight of 800 or greater. Additionally, in this specification, resin-like organopolysiloxanes typically have a viscosity of 1 mPa or greater at 25°C. It should be noted that, 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 using a rotational viscometer according to JIS K 7117-1.

[0028] The resinous organopolysiloxane containing thiol groups (A) has at least two thiol groups per molecule. The resinous organopolysiloxane containing thiol groups may have thiol groups at the ends of the polymer chains and may have silicon atoms at positions other than the ends of the polymer chains, i.e., it may have thiol groups as side groups. In the specification of this application, thiol groups are groups represented by R-SH (here, R represents an organic group, such as a hydrocarbon group), examples of which are alkyl thiol groups, with more specific examples including C1-C... 12 Alkyl thiol group.

[0029] Examples of silicon-bonded organic groups other than thiol groups contained in component (A) include C 1-12 Alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C 6-12 Aryl groups, such as phenyl, tolyl, xylyl, and naphthyl; C 7-12 Aryl groups, such as benzyl, phenethyl, and phenylpropyl; C 2-12 Alkenyl groups, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl; and groups in which some or all of the hydrogen atoms of these groups are replaced by halogen atoms such as fluorine, chlorine, and bromine atoms. It should be noted that, without prejudice to the purpose of the invention, small amounts of hydroxyl or alkoxy groups, such as methoxy or ethoxy groups, may be bonded to the silicon atoms in component (A). Groups bonded to silicon atoms other than thiol groups are preferably selected from C... 1-12 Alkyl groups, and especially methyl groups.

[0030] The resinous organopolysiloxane (A) containing thiol groups may or may not contain alkenyl groups, but preferably does not contain alkenyl groups. Furthermore, the resinous organopolysiloxane (A) containing thiol groups may or may not contain aryl groups, but preferably does not contain aryl groups.

[0031] In one embodiment of the present invention, the resin-like organopolysiloxane (A) containing thiol groups can be an organopolysiloxane resin that can be represented by the following formula (Ia): Average unit form (Ia): (R) 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d (XO1 / 2 ) e [In the formula, R 1 moieties may be the same as or different from each other and are monovalent hydrocarbon groups which may be substituted by at least one halogen, provided that in one molecule, at least two R 1 moieties represent an organic group containing a mercapto group, X represents a hydrogen atom or an alkyl group, and the relationships 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. If the total number of silicon atoms is taken as 1, e represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms)].

[0032] The organic group containing a mercapto group is not particularly limited, but preferred examples include alkyl mercapto groups, and more specific examples thereof include C1-C 12 alkyl mercapto groups.

[0033] In the above formula (I-a), examples of the monovalent hydrocarbon group which may be halogen-substituted other than the organic group containing a mercapto group for R1 include organic groups bonded to a silicon atom other than the above-mentioned mercapto groups, and preferred examples thereof 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; and groups in which some or all of the hydrogen atoms in these groups are substituted with halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms. As long as the object of the present invention is not impaired, R 1 may be a small amount of a hydroxyl group or an alkoxy group, such as a methoxy group or an ethoxy group. R other than the organic group containing a mercapto group 1 moiety is preferably an alkyl group having 1 to 6 carbon atoms, and especially methyl.

[0034] X in the above formula (I-a) 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 methyl, ethyl, and propyl.

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

[0036] In a preferred embodiment of the invention, the resin-like organopolysiloxane containing thiol groups has silicon atoms at positions other than the ends of the polymer chain, that is, it has thiol groups as side groups, and does not have thiol groups in the M unit.

[0037] Therefore, in one embodiment of the present invention, the resinous organopolysiloxane (A) containing thiol groups can be an organopolysiloxane resin that can be represented by the following formula (Ib): Average unit form (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 2The components may be the same as or different from each other, and are monovalent hydrocarbon groups other than thiol groups that can be substituted with at least one halogen, R 1 The components may be the same as or different from each other, and may be monovalent hydrocarbon groups that can be substituted by at least one halogen, but in a molecule, at least two R groups are present. 1 Partially representing an organic group containing a thiol group, X represents a hydrogen atom or an alkyl group, and satisfies the relationships 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. If the total number of silicon atoms is taken as 1, then e represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms).

[0038] Organic groups containing thiol groups and monovalent hydrocarbon groups that can be substituted with halogens are as explained above with respect to formula (Ia). Furthermore, the definitions and preferred ranges of X, a, b, c, d, and e are also as explained above with respect to formula (Ia).

[0039] In a preferred embodiment of the present invention, the resinous organopolysiloxane (A) containing thiol groups may or may not contain R2-SiO2. 2 / 2 The siloxane unit (D unit) is represented, but preferably does not contain the siloxane unit. In this preferred embodiment, it is preferable to bond an organic group containing a thiol group to R-SiO. 3 / 2 The siloxane unit (T unit) is represented.

[0040] Therefore, in one embodiment of the present invention, the resinous organopolysiloxane (A) containing thiol groups can be an organopolysiloxane resin that can be represented by the following formula (Ic): Average unit form (Ib): (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 The components may be the same as or different from each other, and are monovalent hydrocarbon groups other than thiol groups that can be substituted with at least one halogen, R 1 The components may be the same as or different from each other, and may be monovalent hydrocarbon groups that can be substituted by at least one halogen, but in a molecule, at least two R groups are present. 1Partially representing an organic group containing a thiol group, X represents a hydrogen atom or an alkyl group, and satisfies the relationships 0 ≤ a < 1, 0 ≤ c < 0.95, 0 < d < 0.9, 0 ≤ e < 0.4, and a + c + d = 1.0. If the total number of silicon atoms is taken as 1, then e represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms).

[0041] Organic groups containing thiol groups and monovalent hydrocarbon groups that can be substituted with halogens are as explained above with respect to formula (Ia). Furthermore, the definitions and preferred ranges of X, a, c, d, and e are also as explained above with respect to formula (Ia).

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

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

[0044] The number-average molecular weight of the resinous organopolysiloxane (A) containing thiol groups is not particularly limited, but is in the range of, for example, 800-100,000. It should be noted that, in this specification, the number-average molecular weight can be measured by GPC.

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

[0046] Based on the total mass of the composition, component (A) may be included in an amount of 5-90% by mass, preferably 10-85% by mass, more preferably 15-80% by mass, and particularly preferably 20-80% by mass.

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

[0048] Silicone reactive diluent (B) 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 containing at least two alkenyl groups per molecule and including M and Q units, and mixtures thereof.

[0049] Silicone reactive diluent (B) is a liquid at room temperature and can act as a dispersant to reduce the viscosity of curable silicone compositions and increase their flowability. Furthermore, the silicone reactive diluent can also act as a curing accelerator.

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

[0051] Examples of organosilanes having at least two alkenyl groups per molecule of component (B) include polyunsaturated silanes, and their type is not particularly limited, but may be selected from, for example, monosilane compounds such as dimethyldivinylsilane, methyltrivinylsilane, tetravinylsilane, diallylmethylsilane, and diallyldimethylsilane.

[0052] The cyclic organopolysiloxane containing at least two alkenyl groups per molecule of component (B) can preferably be represented by the following: Average structural formula (II-a): (R 4 2SiO) n (In equation (II-a), R) 4 The components may be the same as or different from each other, and may be halogen-substituted or unsubstituted monovalent hydrocarbon groups, but in a molecule, at least two R groups are present. 4 Part of it is alkenyl, and the value of n is 4-15, preferably 4-10, and more preferably 4-8).

[0053] In equation (II-a) above, R4 The halogenated or unsubstituted monovalent hydrocarbon group can react with R in the above formula (Ia). 1 The same as those in the above, and preferably selected from alkyl groups having 1-12 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 6-20 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl; alkenyl groups having 2-12 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl; and groups in which some or all of the hydrogen atoms in these groups are replaced by halogen atoms such as fluorine, chlorine, and bromine atoms. R 4 Preferably selected from alkyl groups having 1-6 carbon atoms, and especially methyl groups, or alkenyl groups having 2-6 carbon atoms, and especially vinyl groups.

[0054] Component (B) is an organopolysiloxane compound containing M and Q units and having at least two alkenyl groups per molecule, which contains only R3-SiO2. 1 / 2 The siloxane unit (M unit) and the siloxane unit (M unit) represented by SiO2 are shown. 4 / 2 The organopolysiloxane represents the siloxane unit (Q unit). The organopolysiloxane compound of component (B) can preferably be represented by the following average unit formula (II-b). Average unit form (II-b): (R) 4 3SiO 1 / 2 ) s (SiO 4 / 2 ) t In the formula, R 4 The components may be the same as or different from each other, and may be halogen-substituted or unsubstituted monovalent hydrocarbon groups, but in a molecule, at least two R groups are present. 4 Part of it is alkenyl, and 0 < s < 1, 0 < t < 1, and s + t = 1.

[0055] In equation (II-b), R 4 This is as explained above regarding equation (II-a).

[0056] In equation (II-b), the value of s preferably falls within the range of 0.3 ≤ s ≤ 0.95, more preferably within the range of 0.5 ≤ s ≤ 0.9, and even more preferably within the range of 0.7 ≤ s ≤ 0.85. In the above equation (II-b), the value of t preferably falls within the range of 0.05 ≤ t ≤ 0.5, more preferably within the range of 0.1 ≤ t ≤ 0.4, and particularly preferably within the range of 0.15 ≤ t ≤ 0.3.

[0057] The viscosity of the organopolysiloxane compound containing M and Q units and having at least two alkenyl groups per molecule is not particularly limited, but can generally be from 0.1 mPa to 1000 mPa at 25°C.

[0058] The content of alkenyl groups in component (B) of cyclic organopolysiloxanes and / or organopolysiloxane compounds containing M and Q units relative to all silicon-bonded organic groups is not particularly limited, but may be, for example, 10 mol% or more, preferably 20 mol% or more, and more preferably 30 mol% or more, of the total amount of silicon-bonded organic groups, and may be 70 mol% or less, preferably 60 mol% or less, and more preferably 55 mol% or less, of the total amount of silicon-bonded organic groups. It should be noted that, in this specification, the content of alkenyl groups in the organopolysiloxane component can be determined by using, for example, analytical methods such as Fourier transform infrared spectroscopy (FT-IR) or nuclear magnetic resonance (NMR), or by using the titration method described below.

[0059] The method for quantitatively determining the amount of alkenyl groups in a component using titration will now be explained. The content of alkenyl groups in an organopolysiloxane component can be quantitatively determined with high accuracy using a titration method commonly known as the Wijs method. The principle of this method is explained below. First, the 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 in the reaction shown in formula (2), thereby releasing iodine. The released iodine is then titrated with sodium thiosulfate solution. Equation (1): CH2=CH- + 2ICl → CH2I-CHCl- + ICl (excess) Equation (2): ICl + KI → I2 + KCl The amount of alkenyl groups in the component can be quantitatively determined by the difference between the amount of sodium thiosulfate required for titration and the titration amount of a blank solution produced separately.

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

[0061] The viscosity of the silicone reactive diluent (B) is not particularly limited, but it can typically be from 0.1 mPa to 1000 mPa at 25°C.

[0062] In one embodiment of the invention, component (B) is included in an amount exceeding 2% by mass of the total mass of the photocurable silicone composition based on the invention. Based on the total mass of the photocurable silicone composition, the content of component (B) is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more. Furthermore, based on the total mass of the photocurable silicone composition of the invention, the content of component (B) is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less. Additionally, based on the total mass of the photocurable silicone composition, the content of component (B) can be in the range of 3-70% by mass, preferably in the range of 5-60% by mass, and even more preferably in the range of 7-50% by mass.

[0063] In one embodiment of the invention, if component (B) contains an organopolysiloxane compound comprising M and Q units, the content of the organopolysiloxane compound, based on the total mass of the photocurable silicone composition of the invention, can preferably be 3% by mass or more, and more preferably 4% by mass or more, and can preferably be 40% by mass or less, more preferably 30% by mass or less, further preferably 20% by mass or less, and particularly preferably 10% by mass or less. Furthermore, based on the total mass of the photocurable silicone composition of the invention, the content of the organopolysiloxane compound in component (B) can be 3-40% by mass, 3-30% by mass, 4-20% by mass, or 4-10% by mass.

[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 photopolymerization initiator (C) or a combination of two or more types of photopolymerization initiators (C).

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

[0066] Examples of alkyl phenyl ketone photopolymerization initiators include 1-hydroxycyclohexylphenyl ketone, marketed by IGM Resins BV under the product name Omnirad 184; hydroxyacetophenone compounds such as 2-hydroxy-2-methyl-1-phenyl-1-propanone (marketed by IGM Resins BV under the product name Omnirad 1173), 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylpropanone (marketed by IGM Resins BV under the product name Omnirad 2959), oligomeric [2-hydroxy-2-methyl-1-[4-(1-methylvinyl)-phenyl]-propanone] and 1,1'-(methylene-di-4,1-phenylene)bis[2-hydroxy-2-methyl-1-propanone] (marketed by IGM Resins BV under the product name Omnirad). 127 sales); aminoacetophenone compounds, such as 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-propane-1-one (sold by Aygenmont Resins under the product name Omnirad 907), 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butane-1-one (sold by Aygenmont Resins under the product name Omnirad 907). 379EG (sold), 2-benzyl-2-dimethylamino-1-(3,4-dimethoxy-phenyl)-butane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholin-4-yl-phenyl)-butane-1-one, 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone (sold by Ajium Resin Company under the product name Omnirad 369), and 2-methyl-1-(4-methylthioalkyl-phenyl)-2-morpholin-4-yl-propane-1-one; 2,2-dimethoxy-2-phenylacetophenone, 4-phenoxydichloroacetophenone, 4-tert-butyldichloroacetophenone, 4-tert-butyltrichloroacetophenone, and combinations thereof.

[0067] Acylphosphine oxide photopolymerization initiators can be selected from, for example, (2,4,6-trimethylbenzoyl)-diphenylphosphine oxide (marketed by Omnirad Resins under the product name Omnirad TPO-H), phenyl-(2,4,6-trimethylbenzoyl)-ethyl phosphate (marketed by Omnirad Resins under the product name Omnirad TPO-L), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (marketed by Omnirad Resins under the product name Omnirad 819), bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and combinations thereof.

[0068] Hydrogen-abstracting photopolymerization initiators can be selected from oxyphenyl photopolymerization initiators, such as methyl benzoylformate, which is marketed by Ajmont Resins under the product name Omnirad MBF.

[0069] In particular, photopolymerization initiators may include oxyethoxyphenylacetyl derivatives, which also correspond to intramolecular hydrogen abstraction photopolymerization initiators. Specific examples of oxyethoxyphenylacetyl derivatives include blends 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 Ajenmont Resins under the product name Omnirad 754) and mixtures thereof.

[0070] Oxime ester photopolymerization initiators can be selected from, for example, 1-[4-(phenylthio)phenyl]-1,2-octanedione-2-(o-benzoyl oxime) (marketed by BASF under the product name Irgacure OXE-01), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]acetophenone-1-(o-acetyl oxime) (marketed by BASF under the product name Irgacure OXE-01), and combinations thereof.

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

[0072] Examples of α-hydroxyacetophenone compounds include 2-hydroxy-2-methyl-1-phenyl-1-propanone (product name: Omnirad 1173, manufactured by Ajium Resin Inc.), 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylpropanone (product name: Omnirad 2959, manufactured by Ajium Resin Inc.), 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] (product name: Omnirad 127D, manufactured by Ajium Resin Inc.), and 1-hydroxycyclohexyl-phenyl ketone (product name: Omnirad 184, manufactured by Ajium Resin Inc.).

[0073] In addition to α-hydroxyacetophenone, the photopolymerization initiator of component (C-1) may further include compounds having an acetophenone structure other than α-hydroxyacetophenone. Such compounds having an acetophenone structure are not particularly limited, but examples include 4-phenoxydichloroacetophenone, 4-tert-butyldichloroacetophenone, 4-tert-butyltrichloroacetophenone, and diethoxyacetophenone.

[0074] In a particularly preferred embodiment, the photoinitiator (C-1) comprising α-hydroxyacetophenone comprises only α-hydroxyacetophenone and does not include other photoinitiators, or comprises another photoinitiator in an amount of 10% or less, 5% or less, or 3% or less of the total mass of component (C).

[0075] In the combination of α-hydroxyacetophenone and α-aminoalkylphenyl ketone (C-2), examples of α-aminoalkylphenyl ketone include 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-propane-1-one (product name: Omnirad 907, manufactured by Ajium Resins), 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butane-1-one (product name: Omnirad 379EG, manufactured by Ajium Resins), 2-benzyl-2-dimethylamino-1-(3,4-dimethoxy-phenyl)-butane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholin-4-yl-phenyl)-butane-1-one, 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone (product name: Omnirad). 369 (produced by Agimont Resins) and 2-methyl-1-(4-methylthioalkyl-phenyl)-2-morpholin-4-yl-propane-1-one.

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

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

[0078] In the combination of α-hydroxyacetophenone and monoacylphosphine oxide (C-3), examples of monoacylphosphine oxide include (2,4,6-trimethylbenzoyl)-diphenyl-phosphine oxide (product name: Omnirad TPO-H, manufactured by Ajium Resin Inc.) and phenyl-(2,4,6-trimethylbenzoyl)-phosphine ethyl ester (product name: Omnirad TPO-L, manufactured by Ajium Resin Inc.).

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

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

[0081] In this specification, examples of "other photoinitiators" are not particularly limited, but include photopolymerization initiators other than those given as examples of components (C-1) to (C-3) above, such as bis-acylphosphine oxide, tri-acylphosphine oxide, phenyl glyoxylate, thioxanone, benzoin ether, and oxime esters. The photopolymerization initiator (C) of this invention does not contain a photopolymerization initiator other than α-hydroxyacetophenone, α-aminoalkylphenyl ketone, or monoacylphosphine oxide, or may contain another photopolymerization initiator 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 component (C).

[0082] In one specific embodiment of the present invention, the photopolymerization initiator (C) is preferably selected from alkyl phenyl ketone type photopolymerization initiators. In another specific embodiment of the present invention, the photopolymerization initiator (C) includes only alkyl phenyl ketone type photopolymerization initiators and does not include other photopolymerization initiators.

[0083] In a specific embodiment of the present invention, the photopolymerization initiator (C) does not contain any phosphorus atoms.

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

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

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

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

[0088] Alkoxylated polyol-derived (meth)acrylates can be monofunctional alkoxylated polyol-derived (meth)acrylates or difunctional, trifunctional, or tetrafunctional polyfunctional alkoxylated polyol-derived (meth)acrylates.

[0089] The polyol portion of alkoxylated polyol-derived (meth)acrylates can be selected from di- to octa-membered polyols. Examples of di- to octa-membered polyols include diols such as ethylene glycol, propylene glycol, butanediol, hexamethylene glycol, and neopentyl glycol; and triols such as 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, and 2,3,4-hexanetriol. 4-Propyl-3,4,5-Heptanetriol, 2,4-Dimethyl-2,3,4-Pentanetriol, pentamethylglycerol, pentaglycerol, 1,2,4-Butanetriol, 1,2,4-Pentanetriol, trimethylolethane and trimethylolpropane, and tetraols such as pentaerythritol, 1,2,3,4-Pentanetriol, 2,3,4,5-Hexanetriol, 1,2,4,5-Pentanetriol and 1,3,4,5-Hexanetriol.

[0090] The alkoxylated portion in alkoxylated polyol-derived (meth)acrylates can be selected from methoxylated, ethoxylated, butoxylated, and propoxylated portions. The number of repeating units in the alkoxylated portion of the alkoxylated polyol-derived (meth)acrylate is not particularly limited, but is typically 1-30, preferably 1-20, more preferably 1-10, and even more preferably 1-5.

[0091] As monofunctional alkoxylated polyol-derived (meth)acrylates, references may be made to methoxyethylene glycol acrylate, methoxypolypropylene glycol acrylate, methoxypolyethylene glycol acrylate, ethoxydiethylene glycol acrylate, and neopentyl glycol propoxylated methyl ether monoacrylate.

[0092] As bifunctional alkoxylated polyol-derived (meth)acrylates, alkoxylated neopentyl glycol diacrylates such as ethoxylated neopentyl glycol diacrylate and propoxylated neopentyl glycol diacrylate can be mentioned.

[0093] As trifunctional alkoxylated polyol-derived (meth)acrylates, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, and propoxylated glycerol triacrylate may be mentioned.

[0094] As a tetrafunctional alkoxylated polyol-derived (meth)acrylate, ethoxylated pentaerythritol tetraacrylate can be mentioned.

[0095] Quinone-derived compounds can be quinone methyl compounds. As a specific example of a quinone methyl compound, 2,6-bis(1,1-dimethylethyl)-4-(phenylenemethylene)cyclohexane-2,5-dien-1-one (marketed by BASF under the product name Irgastab(TM) UV22) can be mentioned.

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

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

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

[0099] There are no particular restrictions on antioxidants, but examples include hindered phenolic antioxidants, phosphorus antioxidants, lactone antioxidants, hydroxylamine antioxidants, vitamin E antioxidants, and sulfur antioxidants.

[0100] For example, as hindered phenolic antioxidants, triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] (commercially available from BASF under the product name IRGANOX 245), 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (commercially available from BASF under the product name IRGANOX 259), 4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylaniline)-1,3,5-triazine (commercially available from BASF under the product name IRGANOX 565), and pentaerythritol-tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (commercially available from BASF under the product name IRGANOX) can be mentioned. 1010 (commercially available), 2,2-thio-diethylethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (commercially available from BASF under the product name IRGANOX 1035), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (commercially available from BASF under the product name IRGANOX 1076), N,N'-hexamethylene bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamoamide) (commercially available from BASF under the product name IRGANOX 1098), diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate (commercially available from BASF under the product name IRGAMOD295), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (commercially available from BASF under the product name IRGANOX). The following products are available commercially: 1330, tri-(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate (available from BASF under the product name IRGANOX 3114), octyl diphenylamine (available from BASF under the product name IRGANOX 5057), 2,4-bis[(octylthio)methyl)-o-cresol (available from BASF under the product name IRGANOX 1520L), isooctyl-3-(3,5-di-tert-butyl-4-hydroxyphenylpropionate (available from BASF under the product name IRGANOX 1135), and 2,4-bis(dodecylthiomethyl)-6-methylphenol (available from BASF under the product name IRGANOX). 1726 is commercially available), 2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)chroman-6-ol (which is commercially available from BASF under the product name IRGANOX E201), 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)benzofuran-2(3H)-one (which is commercially available from BASF under the product name IRGANOX HP-136), and combinations thereof.

[0101] For example, as phosphorus-type antioxidants, tris(2,4-di-tert-butylphenyl)phosphite (commercially available from BASF under the product name IRGAFOS 168), tris[2-[[2,4,8,10-tetra(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphatidylheptacycloheptatrien-6-yl]oxy]ethyl]amine (commercially available from BASF under the product name IRGAFOS 12), bis(2,4-di-tert-butyl-6-methylphenyl)ethyl phosphite (commercially available from BASF under the product name IRGAFOS 38), diphenyl-4,4'-diyl-bis[bis(2,4-di-tert-butyl-5-methylphenoxy)phosphine] (commercially available from Osaki Industry Co., Ltd. under the product name GSY-P1O1), and combinations thereof can be mentioned.

[0102] For example, as a lactone-type antioxidant, the product of the reaction between 3-hydroxy-5,7-di-tert-butyl-furan-2-one and o-xylene (CAS No. 181314-48-7) can be mentioned.

[0103] For example, alkylamine oxidation products obtained using reduced tallow as a raw material can be mentioned as hydroxylamine-type antioxidants.

[0104] For example, 3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol can be mentioned as a vitamin E-type antioxidant.

[0105] For example, as sulfur-type antioxidants, didodecyl-3,3-thiobis-propionate (which is commercially available from BASF under the product name IRGANOX PS800) and dioctadecyl-3,3-thiobis-propionate (which is commercially available from BASF under the product name IRGANOX PS802) can be mentioned.

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

[0107] [Chemical Formula 1]

[0108] In the formula, R 1 and R 3Each of the groups independently represents a straight-chain or branched, saturated or unsaturated hydrocarbon group, which preferably has 4 or more carbon atoms, more preferably 5-16 carbon atoms, and even more preferably 6-12 carbon atoms, and may have at least one heteroatom such as O, S or N inserted. R 2 The term indicates an alkyl group, preferably an alkyl group having 1-3 carbon atoms, and more preferably a methyl group.

[0109] In general formula (II), R 1 and R 3 Each preferably represents a straight-chain saturated alkyl group. Preferably, R in formula (II) 1 and R 3 Each represents an alkyl group having at least one carbonyl group (-OC-), carbonyloxy group (-OC-O-), and / or sulfur atom (-S-) inserted.

[0110] In a specific embodiment of the invention, the antioxidant (d-2) is a hindered phenolic antioxidant (i.e., a thioester antioxidant) containing at least two thioester groups, such as 2,4-bis[(octylthio)methyl)-o-cresol, which is commercially available from BASF under the product name IRGANOX 1520L.

[0111] Other examples of antioxidants (d-2) include the following commonly used antioxidants: phenolic compounds, such as 4-methoxyphenol, 4-tert-butylcatechol, and 2,6-di-tert-butyl-4-methylphenol (BHT); hydroquinone compounds, such as 1,4-dihydroxybenzene and 3,5-di-tert-butylbenzene-1,2-diol; quinone compounds, such as 1,4-benzoquinone and naphth-1,2-dione; aromatic nitro compounds, such as 1,3-dinitrobenzene and 1,4-dinitrobenzene; nitrophenolic compounds, such as 2-(sec-butyl)-4,6-dinitrophenol, 4-methyl-2-nitrophenol, and 4-methyl-2,6-dinitrophenol; and amine compounds, such as phenothiazine, N... 1 -Phenyl-N 4 -propylphenyl-1,4-diamine, N-(1,4-dimethylpentyl)-N'-phenyl-p-phenylenediamine, N,N-diethylhydroxylamine and 2,2,6,6-tetramethylpiperidine; nitroso compounds, such as ammonium salts of N-nitrosophenylhydroxylamine; nitrooxy compounds, such as bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate, 1-oxy-2,2,6,6-tetramethylpiperidine, 1-oxy-2,2,6,6-tetramethylpiperidin-4-ol and 1-oxy-2,2,6,6-tetramethyl-4-n-butoxypiperidine; and mixtures thereof.

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

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

[0114] In one embodiment of the invention, the antioxidant (d-2) may contain 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 an alkenyl-containing organopolysiloxane, different from component (B), as an optional component (E). The photocurable silicone composition according to the present invention may contain one type of alkenyl-containing organopolysiloxane (E) or two or more types of alkenyl-containing organopolysiloxane (E).

[0116] Examples of the molecular structures of alkenyl-containing organopolysiloxanes of component (E) include straight-chain, partially branched straight-chain, branched, resinous, and three-dimensional network structures.

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

[0118] Examples of silicon-bonded groups other than alkenyl groups contained in component (E) include halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups, including alkyl groups having 1-12 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 6-20 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups having 7-20 carbon atoms, such as benzyl, phenethyl, and phenylpropyl; epoxy-containing organic groups; and groups in which some or all of the hydrogen atoms in these groups are replaced by halogen atoms such as fluorine, chlorine, and bromine atoms.

[0119] Furthermore, examples of epoxy-containing organic groups include glycidoxyalkyl groups, such as 2-glycidoxyethyl, 3-glycidoxypropyl, and 4-glycidoxybutyl; epoxycycloalkyl groups, such as 2-(3,4-epoxycyclohexyl)-ethyl and 3-(3,4-epoxycyclohexyl)-propyl; and epoxyalkyl groups, such as 3,4-epoxybutyl and 7,8-epoxyoctyl, wherein glycidoxyalkyl groups are preferred, and 3-glycidoxypropyl is particularly preferred.

[0120] Provided that the purpose of the invention is not compromised, the silicon atoms in component (E) may have small amounts of hydroxyl or alkoxy groups, such as methoxy or ethoxy groups.

[0121] The silicon atom-bonded groups in component (E), other than alkenyl groups, are preferably selected from alkyl groups having 1-6 carbon atoms, and especially methyl groups; aryl groups having 6-20 carbon atoms, and especially phenyl groups; or epoxy-containing organic groups, and especially 3-glycidoxypropyl groups.

[0122] In a preferred embodiment of the invention, from the perspective of compatibility with the resinous organopolysiloxane containing thiol groups of component (A), the alkenyl-containing organopolysiloxane component (E) has at least one aryl group having 6-20 carbon atoms, and in particular a phenyl group.

[0123] In one embodiment of the invention, component (E) may include a resinous, alkenyl-containing organopolysiloxane as component (E-1). The resinous, alkenyl-containing organopolysiloxane (E-1) may preferably be represented by the following: Average unit (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 equation (III-a), R) 4 The components may be the same as or different from each other, and each may be a halogen-substituted or unsubstituted monovalent hydrocarbon group, but in a molecule, at least two R groups are present. 4Partially alkenyl, and 0 ≤ a < 1, 0 ≤ b < 1, 0 ≤ c < 0.9, 0 ≤ d < 0.5, 0 ≤ e < 0.4, a + b + c + d = 1.0, and c + d > 0).

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

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

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

[0127] In a preferred embodiment of the present invention, the resinous alkenyl-containing organopolysiloxane of component (E-1) comprises a unit with c greater than 0 in formula (III-a), i.e., it is composed of R-SiO 3 / 2 The siloxane unit (T unit) is represented. The resinous organopolysiloxane of component (E-1) may or may not contain components derived from SiO₂. 4 / 2 The siloxane unit (Q unit) is indicated, but preferably does not contain the siloxane unit.

[0128] In a preferred embodiment of the invention, the resinous, alkenyl-containing organopolysiloxane of component (E-1) contains an alkenyl group at the molecule's end. The resinous organopolysiloxane of component (E-1) is preferably formed from R3-SiO2. 1 / 2 The siloxane unit (M unit) represents an alkenyl group, and can be a side chain of the molecular chain (i.e., composed of R2-SiO2). 2 / 2 The siloxane unit (D unit) and the R-SiO2 unit are represented. 3 / 2 The siloxane unit (T unit) represents a siloxane unit that contains, but preferably does not contain, an alkenyl group.

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

[0130] In the case of resinous alkenyl-containing organopolysiloxanes containing component (E-1), its content (the molar percentage of aryl groups relative to all silicon-bonded functional groups in the resinous organopolysiloxane) can be designed as needed, but is typically 5 mol% or more, preferably 10 mol% or more, more preferably 15 mol% or more, further preferably 20 mol% or more, and particularly preferably 25 mol% or more, and is typically 70 mol% or less, preferably 60 mol% or less, and more preferably 55 mol% or less. It should be noted that the aryl content can be determined using analytical methods such as Fourier transform infrared spectroscopy (FT-IR) or nuclear magnetic resonance (NMR).

[0131] Specific examples of resinous organopolysiloxanes of component (E-1) include MDT resin, which is a resinous organopolysiloxane containing M units, D units and T units.

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

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

[0134] Specific examples of MDT resins of component (E-1) include liquid resins represented by the following average structural formula: (Vi(Me3)2SiO) 1 / 2 ) 15 ((Me3)2SiO 2 / 2 ) 35 (PhSiO 3 / 2 ) 50In this formula, Vi represents vinyl, Me represents methyl, and Ph represents phenyl.

[0135] Component (E) may include one or more types of linear alkenyl-containing organopolysiloxanes as component (E-2). The linear alkenyl-containing organopolysiloxane of component (E-2) may preferably be represented by the following: Average structural formula (III-b): R 4 3SiO(R 4 2SiO 2 / 2 ) m SiR 4 3 (In equation (III-b), R) 4 The components may be the same as or different from each other, and may be halogen-substituted or unsubstituted monovalent hydrocarbon groups, but in a molecule, at least two R groups are present. 4 Part of it is alkenyl, and the value of m is 1-500).

[0136] In equation (III-b) above, R 4 The halogenated or unsubstituted monovalent hydrocarbon groups can be the same as those in formula (III-a) above.

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

[0138] Examples of component (E-2) include dimethyl polysiloxanes with both molecular ends capped with dimethylvinylsiloxy groups, dimethyl polysiloxanes with both molecular ends capped with diphenylvinylsiloxy groups, copolymers of dimethyl polysiloxanes and methylphenylsiloxanes with both molecular ends capped with dimethylvinylsiloxy groups, copolymers of dimethyl polysiloxanes and diphenylsiloxanes with both molecular ends capped with dimethylvinylsiloxy groups, copolymers of dimethyl polysiloxanes and methylphenylsiloxanes with both molecular ends capped with diphenylvinylsiloxy groups, copolymers of dimethyl polysiloxanes and methylvinylsiloxanes with both molecular ends capped with dimethylvinylsiloxy groups, and copolymers of dimethyl polysiloxanes and methylvinylsiloxanes with both molecular ends capped with dimethylvinylsiloxy groups. Copolymers of dimethyl polysiloxane, methyl phenyl siloxane, and methyl vinyl siloxane, both molecule-terminated with dimethyl vinyl siloxane, diphenyl siloxane, and methyl vinyl siloxane, methyl vinyl polysiloxane, methyl vinyl polysiloxane, methyl vinyl siloxane, and methyl phenyl siloxane, both molecule-terminated with trimethyl siloxane, methyl vinyl siloxane, and methyl phenyl siloxane, methyl vinyl siloxane, and diphenyl siloxane, and both molecule-terminated with trimethyl siloxane.

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

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

[0141] In the case of linear alkenyl-containing organopolysiloxanes containing component (E-2), its content (the molar percentage of aryl groups relative to all silicon-bonded functional groups in the linear organopolysiloxane) can be designed as needed, but is typically 15 mol% or more, preferably 20 mol% or more, and more preferably 25 mol% or more, and can be 70 mol% or less, preferably 60 mol% or less, and more preferably 55 mol% or less. It should be noted that the aryl content can be determined using analytical methods such as Fourier transform infrared spectroscopy (FT-IR) or nuclear magnetic resonance (NMR).

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

[0143] Epoxy-containing resinous organopolysiloxanes can preferably be represented by 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 equation (III-c), R} 5 Each of the groups is independently either halogenated or unsubstituted monovalent hydrocarbon groups, but at least two R groups are present. 5 Partially alkenyl, at least one R 5 Part of it is an organic group containing an epoxy group, where X is a hydrogen atom or an alkyl group, and 0 ≤ f < 1, 0 ≤ g < 1, 0 ≤ h < 0.9, 0 ≤ i < 0.5, 0 ≤ j < 0.5, f + g + h + i + j = 1.0, and h + i > 0. If the total number of silicon atoms is taken as 1, then j represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms).

[0144] In equation (III-c) above, R 5 Examples of halogenated or unsubstituted monovalent hydrocarbon groups include C 1-12Alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C 6-12 Aryl groups, such as phenyl, tolyl, xylyl, and naphthyl; C 7-12 Aryl groups, such as benzyl, phenethyl, and phenylpropyl; C 2-12 Alkenyl groups, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl; epoxy-containing groups; and groups in which some or all of the hydrogen atoms in these groups are replaced by halogen atoms such as fluorine, chlorine, and bromine atoms. Epoxy-containing organic groups are as explained above. R 5 Preferably selected from alkyl groups having 1-6 carbon atoms, and especially methyl groups, alkenyl groups having 2-6 carbon atoms, and especially vinyl groups, aryl groups having 6-20 carbon atoms, and especially phenyl groups, or 3-glycidoxypropyl groups.

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

[0146] In equation (III-c) above, based on the value of f + g + h + i + j being 1.0, the value of f preferably falls within the range of 0.03 ≤ f ≤ 0.7, more preferably within the range of 0.06 ≤ f ≤ 0.5, and even more preferably within the range of 0.09 ≤ f ≤ 0.3. In equation (III-c) above, the value of g preferably falls within the range of 0.05 ≤ g ≤ 0.6, more preferably within the range of 0.1 ≤ g ≤ 0.4, and particularly preferably within the range of 0.2 ≤ g ≤ 0.3. In equation (III-c) above, the value of h preferably falls within the range of 0.1 ≤ h ≤ 0.8, more preferably within the range of 0.25 ≤ h ≤ 0.7, and particularly preferably within the range of 0.4 ≤ h ≤ 0.6. In equation (III-c) above, the value of i preferably falls within the range of 0 ≤ i ≤ 0.4, more preferably within the range of 0 ≤ i ≤ 0.25, and particularly preferably within the range of 0 ≤ i ≤ 0.1. In equation (III-c) above, the value of j preferably falls within the range of 0.05 ≤ j ≤ 0.4, more preferably within the range of 0.1 ≤ j ≤ 0.3, and particularly preferably within the range of 0.15 ≤ j ≤ 0.25. Furthermore, in equation (III-c), the value of h + i preferably falls within the range of 0.1 ≤ h + i ≤ 0.9, more preferably within the range of 0.2 ≤ h + i ≤ 0.8, and particularly preferably within the range of 0.3 ≤ h + i ≤ 0.7.

[0147] In a preferred embodiment of the present invention, the epoxy-containing resinous organopolysiloxane comprises a unit in formula (III-c) where the value of h is greater than 0, i.e., it is composed of R-SiO 3 / 2 The term represents the siloxane unit (T unit). Component (E-3), a resinous organopolysiloxane containing epoxy groups, may or may not contain components derived from SiO₂. 4 / 2 The siloxane unit (Q unit) is indicated, but preferably does not contain the siloxane unit.

[0148] In a preferred embodiment of the invention, the epoxy-containing organopolysiloxane of component (E-3) contains an alkenyl group at the molecule's end. The epoxy-containing organopolysiloxane is preferably formed from R3-SiO2. 1 / 2 The siloxane unit (M unit) represents an alkenyl group, and can be located in the molecular side chain (i.e., composed of R2-SiO2). 2 / 2 The siloxane unit (D unit) and the R-SiO2 unit are represented. 3 / 2 The siloxane unit (T unit) represents a siloxane unit that contains, but preferably does not contain, an alkenyl group.

[0149] In a preferred embodiment of the invention, the epoxy-containing resinous organopolysiloxane of component (E-3) contains an aryl group in the organic group bonded to silicon atoms. That is, at least one R in formula (III-c) above... 5 The aryl group may be present. In a preferred embodiment of the invention, the epoxy-containing resinous organopolysiloxane contains a silicon-bonded aryl group in the molecular side chain (i.e., in the D unit or T unit, and preferably in the T unit). The epoxy-containing resinous organopolysiloxane may contain, but preferably does not contain, an aryl group at the molecular terminal (i.e., in the M unit). Furthermore, examples of aryl groups include aryl groups having 6-20 carbon atoms, and especially phenyl, tolyl, xylyl, and naphthyl.

[0150] In the case of an epoxy-containing organopolysiloxane (E-3), its content (the molar percentage of aryl groups relative to all silicon-bonded functional groups in the epoxy-containing organopolysiloxane) can be designed as needed, but is preferably 15 mol% or more, more preferably 20 mol% or more, further 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, further preferably 50 mol% or less, and particularly preferably 40 mol% or less.

[0151] The amount of epoxy-containing organic groups in the epoxy-containing organopolysiloxane (E-3) is not particularly limited relative to the total amount of organic groups bonded to silicon atoms, but is preferably 1 mol% or more, more preferably 5 mol% or more, further preferably 10 mol% or more, and particularly preferably 15 mol% or more, and is, for example, 40 mol% or less, preferably 30 mol% or less, and more preferably 25 mol% or less. It should be noted that the amount of epoxy-containing organic groups can be determined using, for example, analytical methods such as Fourier transform infrared spectroscopy (FT-IR) or nuclear magnetic resonance (NMR).

[0152] In a preferred embodiment of the invention, the epoxy-containing organopolysiloxane contains hydroxyl and / or alkoxy groups as organic groups bonded to silicon atoms. The amount of hydroxyl and / or alkoxy groups in the epoxy-containing organopolysiloxane is not particularly limited relative to the total amount of organic groups bonded to silicon atoms, but is preferably 2 mol% or more, more preferably 5 mol% or more, and even more preferably 10 mol% or more, and is, for example, 30 mol% or less, preferably 20 mol% or less, and more preferably 15 mol% or less. It should be noted that the amount of hydroxyl and / or alkoxy groups can be determined using, for example, analytical methods such as Fourier transform infrared spectroscopy (FT-IR) or nuclear magnetic resonance (NMR).

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

[0154] The number-average molecular weight of the organopolysiloxane in component (E-1) is not particularly limited, but can be in the range of 850-10000.

[0155] In one embodiment of the invention, the ratio (SH / Ar) of thiol groups to alkenyl groups in the organosilicon compound contained in the photocurable silicone resin of the invention is not particularly limited, but the amount of thiol groups relative to 1 mole of alkenyl group is preferably 0.2 moles or more, more preferably 0.3 moles or more, and even more preferably 0.4 moles or more, and the amount of thiol groups relative to 1 mole of alkenyl group can be, for example, 5 moles or less, preferably 3 moles or less, more preferably 2 moles or less, even more preferably 1.5 moles or less, and most preferably 1.2 moles or less.

[0156] (F) Inorganic packing The photocurable silicone composition according to the present invention may contain one or more types of inorganic fillers as optional component (F). The inorganic fillers may be selected from inorganic fillers such as powdered quartz, silica, titanium dioxide, magnesium carbonate, zinc oxide, iron oxide and diatomaceous earth, as well as inorganic fillers obtained by subjecting the surface of the above inorganic fillers to hydrophobic treatment using organosilicon compounds.

[0157] The inorganic filler for component (F) is preferably selected from silica. Examples of silica include fumed silica, wet silica, crystalline silica, and precipitated silica. Furthermore, silica can be subjected to surface hydrophobication treatment using organosilicon compounds (such as organoalkoxysilane compounds, organochlorosilane compounds, organosilazane compounds and low molecular weight siloxane compounds, silane coupling agents, and titanate-based coupling agents).

[0158] The amount of component (F) is not particularly limited, but component (F) may be included in the photocurable silicone composition of the present invention in an amount preferably 0.01% by mass or more, more preferably 0.1% by mass or more, further preferably 1% by mass or more, and particularly preferably 3% by mass or more of the total mass of the composition based on the present invention, and may be included in the photocurable silicone composition of the present invention in an amount preferably 20% by mass or less, more preferably 15% by mass or less, and further preferably 10% by mass or less.

[0159] (Optional additives) The photocurable silicone composition according to the invention may contain optional additives commonly used in the technical field of the invention. Such additives include, for example, organic fillers, pigments, tackifiers, resistance-imparting agents, release agents, heat-imparting agents, colorants, flame-retardant-imparting agents, and combinations thereof.

[0160] The curable silicone composition according to the invention is photocurable, and more specifically, can be cured by irradiation with active energy rays (e.g., ultraviolet radiation, etc.). Therefore, in one embodiment of the invention, the photocurable silicone composition of the invention is a UV-curable silicone composition. The wavelength of the ultraviolet radiation used for irradiation is not particularly limited, but is preferably in the range of 360 nm to 395 nm. Irradiation can be carried out at 500-1500 J / cm². 2 The dosage is determined, and the photocurable silicone composition can be cured by using a metal halide lamp with ultraviolet radiation (wavelength 365 nm, 1000 J / cm). 2 The curing is achieved by irradiation. The duration of irradiation is not particularly limited, but is typically 1 to 60 seconds, preferably 5 to 30 seconds, and more preferably 10 to 20 seconds.

[0161] The photocurable silicone composition according to the invention can be cured to form a cured product with good transparency. Specifically, when measured using a sample with a thickness of 1 mm, the cured product of the photocurable silicone composition of the invention preferably has a transmittance of 90% or higher for light with wavelengths from 400 nm to 700 nm. It should be noted that the transmittance of the cured product of the photocurable silicone composition can be determined, for example, by measuring the cured product with an optical path length of 1 using a spectrophotometer.

[0162] The photocurable silicone composition according to the invention can be cured to form a cured product with high hardness. The cured product obtained by curing the photocurable silicone composition of the invention preferably has a Type A hardness of A50 or higher at 25°C. It should be noted that this Type A hardness is determined using a Type A hardness tester according to JIS K 6253-1997.

[0163] The viscosity of the photocurable silicone composition according to the invention is not particularly limited, but 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 type B rotational viscometer (MCR-302 manufactured by Anton Paar GmbH) according to the method described in JIS K 7117-1: 1999.

[0164] The refractive index of the photocurable silicone composition according to the invention is not particularly limited, but when measured using, for example, an Abbe's refractometer, the refractive index at 25°C and a wavelength of 589 nm is preferably greater than 1.4, and more preferably 1.43 or greater, and typically 1.52 or less.

[0165] The photocurable silicone composition according to the invention preferably has a long pot life. For example, in a preferred embodiment of the invention, even when the photocurable silicone composition is stored in a bright room at 25°C for 24 hours, the increase in viscosity is less than 10%. It should be noted that the viscosity measurement is as described above.

[0166] The photocurable silicone composition according to the present invention can be prepared by mixing the above-described basic and optional components using conventional methods. The method for mixing the components can be a conventional and well-known method and is not particularly limited. For example, mixing can be performed by stirring or simply by using a mixing device such as a single-screw or twin-screw continuous mixer, a twin-roll mixer, a Hobart mixer, a dental mixer, a planetary mixer, a kneading mixer, or a Henschel mixer.

[0167] [Sealing materials and sheet membranes] The present invention also relates to a sealing material or sheet film obtained by curing a photocurable silicone composition according to the invention. The sealing material of the present invention can be advantageously used for sealing optical semiconductor elements including optical semiconductors. The sheet film of the present invention can be advantageously used as a sealing material layer for mass transfer or as an adhesive sheet film.

[0168] Examples of semiconductor devices include SiC and GaN. Examples of optical semiconductor devices include 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 coating the photocurable silicone composition of the present invention onto a film, strip, or sheet substrate material, curing the composition by irradiation with active energy rays (e.g., ultraviolet radiation), and forming a cured coating film on the surface of the substrate material. The thickness of the cured coating film is not particularly limited, but is preferably in the range of 1 µm to 10 mm or in the range of 5 µm to 5 mm.

[0170] The present invention includes the following embodiments. Example 1: A photocurable silicone composition comprising: (A) containing at least two thiol groups / molecules and at least one component derived from SiO2. 4 / 2 or R-SiO 3 / 2 The resinous organopolysiloxane containing thiol groups, representing a siloxane unit; (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 containing at least two alkenyl groups per molecule and comprising M and Q units, and mixtures thereof. (C) at least one photopolymerization initiator; and (D) At least one polymerization inhibitor and / or antioxidant. Example 2: The composition according to Example 1, wherein the resinous organopolysiloxane (A) containing thiol groups has thiol groups as side groups and does not have thiol groups at the ends of the polymer chains. Example 3: The composition according to Example 1 or Example 2, wherein the resinous organopolysiloxane (A) containing thiol groups does not contain R2-SiO 2 / 2 The siloxane unit (D unit) is represented. Example 4: The composition according to any one of Examples 1-3, wherein the silicone reactive diluent (B) has a number average molecular weight of less than 800. Example 5: The composition according to any one of Examples 1-4, wherein the photopolymerization initiator (C) contains an alkyl phenyl ketone type photopolymerization initiator. Example 6: The composition according to any one of Examples 1-5, wherein the polymerization inhibitor and / or antioxidant (D) is selected from (d-2) antioxidants. Example 7: The composition according to Example 6, wherein these antioxidants (d-2) include 2,6-di-tert-butyl-4-methylphenol (BHT). Example 8: The composition according to any one of Examples 1-7, wherein the silicone reactive diluent (B) is contained in an amount exceeding 2% by mass based on the total mass of the photocurable silicone composition. Example 9: A sealing material or sheet film formed using a photocurable silicone composition according to any one of Examples 1-8. [Work Example]

[0171] The invention will now be explained in more detail using working examples, but these working examples should not be construed as limiting the scope of the invention.

[0172] The photocurable silicone compositions of the present invention will be explained in more detail using working examples and comparative examples. In these working examples and comparative examples, photocurable silicone compositions were prepared using the following components. In the formulations, Vi represents vinyl, Me represents methyl, Ph represents phenyl, Ep represents an epoxy-containing organic group, and SH represents a thiol group (HSCH2CH2CH2- group). Furthermore, the numerical values ​​expressed in the table are based on the "parts by mass" of the active components of the raw materials. In addition, the structures of the organopolysiloxane components in the table are shown in simplified form, and the text in parentheses indicates the functional groups other than Me in the M, D, and T units. Furthermore, SH / Vi represents the molar ratio of thiol groups (SH) to vinyl groups (Vi) bonded to silicon atoms in the organopolysiloxane component.

[0173] (Components) (a) From the average unit cell (Me3SiO) 1 / 2 ) 43.5 (SHSiO 3 / 2 ) 43 (SiO 4 / 2 ) 13.5 This indicates that each molecule contains at least two thiol groups and at least one component derived from SiO₂. 4 / 2 Resinous organopolysiloxanes containing thiol groups representing siloxane units. (a'-1) Trimethylolpropane tris(3-mercaptobutyrate) (TPMB) (a'-2) [(mercaptopropyl)methylsiloxane]-dimethylsiloxane copolymer (product name SMS-142, manufactured by Gelest) (a'-3) Based on the average structural formula Me3SiO(MeSHSiO) 2 / 2 ) 17.2 SiMe3 represents a straight-chain organopolysiloxane containing thiol groups. (a'-4) 1,2-bis(2-mercaptoethoxy)ethane, 3,6-dioxa-1,8-octane-dithiol (DMDO) (b-1) Dimethyldivinylsilane (b-2) Alkenyl-containing organopolysiloxane compounds represented by the formula (Me2ViSiO)4Si (b-3) From formula (MeViSiO) 2 / 2 )4 represents cyclic alkenyl-containing organopolysiloxanes (c) 2-Hydroxy-2-methyl-1-phenyl-1-propanone (product name Omnirad 1173, manufactured by Ajmont Resins) (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) Based on the average structural formula ViMe2SiO(Me2SiO) 2 / 2 )9SiMe2Vi represents a linear alkenyl-containing organopolysiloxane (e-2) From the average unit cell (Me3SiO) 1 / 2 )5(ViMe2SiO 1 / 2 ) 17 (MeSiO 3 / 2 ) 39 (PhSiO 3 / 2 ) 39 Represents a resinous, alkenyl-containing organopolysiloxane with a Mw value of 2700. (e-3) Based on the average structural formula ViMe2SiO(Ph2SiO) 20 SiMe2Vi represents a linear, alkenyl-containing organopolysiloxane. (e-4) From the average unit cell (ViMe2SiO) 1 / 2 ) 25 (PhSiO 3 / 2 ) 75 Represents a resinous, alkenyl-containing organopolysiloxane with a Mw value of 2300. (e-5) Based on the average structural formula ViMe2SiO(Ph2SiO) 20 SiMe2Vi represents a linear, alkenyl-containing organopolysiloxane. (e-6) From the average unit cell (ViMe2SiO) 1 / 2 ) 13 (EpMeSiO 2 / 2 ) 24 (PhSiO 3 / 2 ) 46 (OMe) 17 Represents an epoxy-containing resinous organopolysiloxane having a Mw value of 3400. (e-7) From the average unit cell (Me3SiO) 1 / 2 ) 14 (ViMe2SiO 1 / 2 ) 11 (MeSiO 3 / 2 ) 53 (PhSiO 3 / 2 ) 22 Represents a resinous, alkenyl-containing organopolysiloxane with a Mw value of 5000. (e-8) Based on the average structural formula ViMe2SiO(Me2SiO) 60 (Ph2SiO) 30 SiMe2Vi represents a linear, alkenyl-containing organopolysiloxane. (e-9) From the average unit cell (ViMe2SiO) 1 / 2 ) 15 (Me2SiO 2 / 2 ) 30 (PhSiO 3 / 2 ) 50 Represents a resinous, alkenyl-containing organopolysiloxane with a Mw value of 2700. (f) Fumed silica

[0174] [evaluate] (hardness) By using a metal halide lamp with ultraviolet radiation of 365 nm wavelength at 200 mW / cm², 2 The cumulative irradiation dose was used to irradiate the obtained photocurable silicone composition to obtain a sheet-like cured product with a thickness of 1 mm. The hardness of the obtained cured sample was measured at 25°C using a Type A hardness tester or a Type D hardness tester according to JISK 6253-1997.

[0175] (Light transmittance) A photocurable silicone composition is filled into a mold having a recessed portion of a predetermined shape, and then irradiated with ultraviolet light at a wavelength of 365 nm using a metal halide lamp at a concentration of 200 mW / cm². 2 The cumulative irradiation was applied from above the upper liquid surface to cure the photocurable silicone composition. It should be noted that the UV irradiation duration was 15 seconds. The transmittance of the obtained plate-like cured product at a wavelength of 450 nm was measured at 25°C. Transmittance was measured using samples with a thickness of 1 mm in Working Examples 1-6 and Comparative Examples 1 and 2, and samples with a thickness of 2 mm in Working Examples 7-12 and Comparative Examples 3-6.

[0176] (Changes in light transmittance after heating) The sample whose transmittance has been measured is heat-treated at 260°C for 10 minutes, and then the transmittance is measured at a wavelength of 450 nm and a temperature of 25°C. A change in transmittance of 10% or less after heating is indicated as "OK", and a change in transmittance of more than 10% after heating is indicated as "NG".

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

[0178] (Applicable period) When the obtained photocurable silicone composition is stored at 25°C in a bright room for 24 hours, an increase in viscosity of less than 10% is considered "OK".

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

[0180] (Chip shear strength) The obtained photocurable composition was uniformly coated onto a glass sheet. Next, another glass sheet was placed over the composition, and the composition was irradiated with UV light (365 nm, 200 mW / cm²) using a metal halide lamp. 2 The material is cured to obtain a sheet with a thickness of 1 mm. The chip shear strength is measured using a chip shear tester (a DAGE4000 adhesive tester manufactured by Nordson DAGE). Samples with a chip shear strength of 2 MPa or greater are indicated as "OK".

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

[0182] [Table 1]

[0183] [Table 2]

[0184] [Table 3]

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

[0186] Preferred embodiments of the invention are as described above, but the invention should not be considered limited to these embodiments. Features may be added, omitted, substituted, or otherwise modified within the scope of the invention. The invention is not limited by the foregoing explanations, but only by the scope of the appended claims.

Claims

1. A photocurable silicone composition comprising: (A) a resinous organopolysiloxane containing thiol groups, said organopolysiloxane containing at least two thiol groups / molecules and at least one SiO2 group. 4 / 2 Unit (Q unit) or made of R-SiO 3 / 2 (where R means monovalent organic group) represents the siloxane unit (T unit); (B) A silicone reactive diluent, said silicone reactive diluent being selected from organosilane compounds containing at least two alkenyl groups per molecule, cyclic organopolysiloxanes containing at least two alkenyl groups per molecule, and compounds containing at least two alkenyl groups per molecule and comprising R3-SiO2. 1 / 2 Organopolysiloxane compounds, and mixtures thereof, representing siloxane units (M units) and Q units; (C) at least one photopolymerization initiator; and (D) At least one polymerization inhibitor and / or antioxidant.

2. The composition according to claim 1, wherein, The resin-like organopolysiloxane (A) containing thiol groups has thiol groups as side groups and does not have thiol groups in the M unit.

3. The composition according to claim 1 or claim 2, wherein, The resinous organopolysiloxane (A) containing thiol groups does not contain R2-SiO2. 2 / 2 The siloxane unit (D unit) is represented.

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

5. The composition according to claim 1, wherein, The photopolymerization initiator (C) contains an alkyl phenyl ketone type photopolymerization initiator.

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

7. The composition according to claim 6, wherein, The antioxidant (d-2) includes 2,6-di-tert-butyl-4-methylphenol (BHT).

8. The composition according to claim 1, wherein, The silicone reactive diluent (B) is contained in an amount exceeding 2% by mass based on the total mass of the photocurable silicone composition.

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

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