Photocurable silicone composition, sealing material, and sheet film

Abstract

The present invention relates to a photocurable silicone composition comprising: (A) a resin-like thiol group-containing organopolysiloxane that contains at least two thiol groups per molecule and at least one SiO4 / 2 (Q unit) or siloxane unit (T unit) represented by R-SiO3 / 2 (wherein R means a monovalent organic group); and (B) a silicone reactive diluent selected from an organic silane compound containing at least two alkenyl groups per molecule, a cyclic organopolysiloxane containing at least two alkenyl groups per molecule, an organopolysiloxane compound containing at least two alkenyl groups per molecule and comprising a siloxane unit (M unit) represented by R3-SiO1 / 2 and the Q unit, and a mixture thereof.

Description

Photocurable silicone composition, sealing material, and sheet film

[0001] The present invention relates to a photocurable silicone composition and an encapsulant or sheet film formed from the photocurable silicone composition. This application claims priority based on Japanese Patent Application No. 2023-185633, filed October 30, 2023, the contents of which are incorporated herein by reference.

[0002] Curable silicone compositions are used in a wide range of industrial fields because they form cured products that have excellent heat resistance, cold resistance, electrical insulation, weather resistance, water repellency, and transparency. Cured products of these curable silicone compositions are less susceptible to discoloration than other organic materials and experience only a small decrease in physical properties, making them suitable for use as optical materials and encapsulants for semiconductor devices.

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

[0004] Photocurable silicone compositions may contain mercapto-functional compounds to improve the shape stability of the cured product, etc. Several applications have been published to date that describe photocurable silicone compositions containing mercapto-functional compounds.

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

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

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

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

[0009] However, although photocurable silicone compositions containing mercapto-functional compounds have excellent shape stability when cured, they suffer from the problem that they may not have sufficient hardness.

[0010] International Publication No. WO2018 / 223365, Japanese Patent Application Laid-Open No. 2013-253179, International Publication No. WO2021 / 167051, Japanese Patent Application Laid-Open No. 2022-19171

[0011] An object of the present invention is to provide a photocurable silicone composition containing at least one thiol-functional organopolysiloxane that can form a cured product with excellent hardness and transparency.

[0012] The object of the present invention is to provide a polymer having at least two thiol groups and at least one SiO ４／２ (Q unit) or R—SiO ３／２ (B) an organosiloxane compound containing at least two alkenyl groups per molecule, a cyclic organopolysiloxane containing at least two alkenyl groups per molecule, a siloxane unit (T unit) represented by the formula: (where R represents a monovalent organic group, for example, a monovalent hydrocarbon group; the same applies hereinafter); (C) an organosilane compound containing at least two alkenyl groups per molecule, a cyclic organopolysiloxane containing at least two alkenyl groups per molecule, a siloxane unit (T unit) represented by the formula: ３ -SiO １／２ and Q units represented by the following formula (1):

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

[0014] (A) The resinous thiol group-containing organopolysiloxane is preferably R ２ -SiO ２／２ The siloxane unit represented by the formula (D unit) is not included.

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

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

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

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

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

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

[0021] The photocurable silicone composition of the present invention contains a thiol group-containing organopolysiloxane and can form a cured product that exhibits excellent hardness and transparency. In particular, the cured product of the present invention can maintain its excellent transparency even after heat treatment.

[0022] As a result of extensive research, the inventors surprisingly discovered that a photocurable silicone composition containing a thiol group-containing organopolysiloxane having a specific structure and a predetermined amount of a silicone-reactive diluent containing at least two alkenyl groups per molecule can form a cured product that exhibits excellent hardness and transparency, leading to the completion of the present invention.

[0023] Therefore, the composition of the present invention comprises: (A) at least two thiol groups and at least one SiO ４／２ or R—SiO ３／２(B) a silicone-reactive diluent selected from organosilane compounds containing at least two alkenyl groups per molecule, cyclic organopolysiloxanes containing at least two alkenyl groups per molecule, organopolysiloxane compounds consisting of M units and Q units each containing at least two alkenyl groups per molecule, and mixtures thereof; (C) at least one photopolymerization initiator; and (D) at least one polymerization inhibitor and / or antioxidant.

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

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

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

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

[0028] (A) Resin-like thiol group-containing organopolysiloxane has at least two thiol groups per molecule. The resin-like thiol group-containing organopolysiloxane may have a thiol group at the end of the polymer chain, or may have a thiol group on a silicon atom other than the end of the polymer chain, i.e., as a pendant group. In this specification, the thiol group is a group represented by R-SH (where R represents an organic group, such as a hydrocarbon chain), and examples include alkylthiol groups. More specifically, C １ ~C１２ Examples include alkylthiol groups.

[0029] Examples of silicon-bonded organic groups other than thiol groups contained in component (A) include C groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups. １～１２ Alkyl group: C such as phenyl group, tolyl group, xylyl group, and naphthyl group ６～１２ Aryl group: C such as benzyl group, phenethyl group, and phenylpropyl group ７～１２ Aralkyl groups include vinyl groups, allyl groups, butenyl groups, pentenyl groups, hexenyl groups, heptenyl groups, octenyl groups, nonenyl groups, decenyl groups, undecenyl groups, and dodecenyl groups. ２～１２ alkenyl groups; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine atoms, chlorine atoms, or bromine atoms. A small amount of hydroxyl groups or alkoxy groups such as methoxy groups or ethoxy groups may be bonded to the silicon atoms in component (A) within the scope of the present invention. The groups bonded to silicon atoms other than thiol groups are preferably C １～１２ It is selected from alkyl groups, in particular methyl groups.

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

[0031] In one embodiment of the present invention, the resinous thiol group-containing organopolysiloxane (A) is represented by the following formula (Ia): Average unit formula (Ia): (R １ ３ SiO １／２ ) ａ (R １ ２ SiO ２／２ ) ｂ (R １ SiO ３／２ ) ｃ (SiO４／２ ) ｄ (XO １／２ ) ｅ [In the formula, R １ are the same or different monovalent hydrocarbon groups which may be substituted with at least one halogen, provided that at least two R １ represents a thiol group-containing organic group, X represents a hydrogen atom or an alkyl group, and satisfies the conditions 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. e represents the number of (XO) groups when the total number of silicon atoms is 1 (the ratio of the number of (XO) groups to the total number of silicon atoms).

[0032] The thiol group-containing organic group is not particularly limited, but preferably includes an alkylthiol group, and more specifically, １ ~C １２ Examples include alkylthiol groups.

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

[0034] X in the above formula (Ia) is a hydrogen atom or an alkyl group. The alkyl group for X is preferably an alkyl group having 1 to 3 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, and a propyl group.

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

[0036] In one preferred embodiment of the present invention, the resinous thiol group-containing organopolysiloxane has thiol groups on silicon atoms other than those at the ends of the polymer chain, i.e., as pendant groups, and does not have thiol groups in the M units.

[0037] Therefore, in one embodiment of the present invention, the resinous thiol group-containing organopolysiloxane (A) is represented by the following formula (I-b): Average unit formula (I-b): (R ２ ３ SiO １／２ ) ａ (R １ ２ SiO ２／２ ) ｂ (R １ SiO ３／２ ) ｃ (SiO ４／２ )ｄ (XO １／２ ) ｅ [In the formula, R ２ are the same or different monovalent hydrocarbon groups other than thiol-containing organic groups, which may be substituted with at least one halogen, and R １ are the same or different monovalent hydrocarbon groups which may be substituted with at least one halogen, provided that at least two R １ represents a thiol group-containing organic group, X represents a hydrogen atom or an alkyl group, and satisfies the conditions 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. e represents the number of (XO) groups when the total number of silicon atoms is 1 (the ratio of the number of (XO) groups to the total number of silicon atoms).

[0038] The thiol group-containing organic group and the optionally halogen-substituted monovalent hydrocarbon group are as described above for formula (I-a). The definitions and preferred ranges of X, a, b, c, d, and e are also as described above for formula (I-a).

[0039] In a preferred embodiment of the present invention, the resinous thiol group-containing organopolysiloxane (A) is R ２ -SiO ２／２ In this preferred embodiment, the thiol group-containing organic group is preferably a siloxane unit (D unit) represented by the formula: ３／２ The siloxane unit (T unit) is represented by the formula:

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

[0041] The thiol group-containing organic group and the optionally halogen-substituted monovalent hydrocarbon group are as described above for formula (I-a). The definitions and preferred ranges of X, a, c, d, and e are also as described above for formula (I-a). is also as described above for formula (I-a).

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

[0043] The viscosity of the resinous thiol group-containing organopolysiloxane (A) is not particularly limited, but can be, for example, 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 in accordance with JIS K7117-1.

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

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

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

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

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

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

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

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

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

[0053] In the above formula (II-a), R ４ is R in the above formula (Ia). １The same groups as those mentioned above can be applied, and preferably R is selected from 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 groups; aryl groups having 6 to 20 carbon atoms such as phenyl, tolyl, xylyl, and naphthyl groups; alkenyl groups having 2 to 12 carbon atoms such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl groups; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, chlorine, and bromine atoms. ４ is preferably selected from alkyl groups having 1 to 6 carbon atoms, in particular methyl groups, and alkenyl groups having 2 to 6 carbon atoms, in particular vinyl groups.

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

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

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

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

[0058] The alkenyl group content of all silicon-bonded organic groups in the cyclic organopolysiloxane and / or organopolysiloxane compound comprising M units and Q units of component (B) 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 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 silicon-bonded organic groups. In this specification, the alkenyl group content in the organopolysiloxane component can be determined, for example, by analytical methods such as Fourier transform infrared spectroscopy (FT-IR) or nuclear magnetic resonance (NMR), or by the titration method described below.

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

[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 not more than 500. There is no particular lower limit for the number average molecular weight of component (B), but it is usually 100 or more.

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

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

[0063] In one embodiment of the present invention, when component (B) contains an organopolysiloxane compound composed of M units and Q units, the content of this organopolysiloxane compound, based on the total mass of the photocurable silicone composition of the present invention, is preferably 3 mass% or more, more preferably 4 mass% or more, and is preferably 40 mass% or less, more preferably 30 mass% or less, even more preferably 20 mass% or less, and particularly preferably 10 mass% or less. Furthermore, the content of the organopolysiloxane compound as component (B), based on the total mass of the photocurable silicone composition of the present invention, can be within a range of 3 to 40 mass%, 3 to 30 mass%, 4 to 20 mass%, or 4 to 10 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 (C) photopolymerization initiator, or may contain a combination of two or more types of (C) photopolymerization initiators.

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

[0066] Examples of alkylphenone photoinitiators include 1-hydroxycyclohexyl-phenyl ketone sold under the name Omnirad 184 by IGM Resins B.V.; 2-hydroxy-2-methyl-1-phenyl-1-propanone sold under the name Omnirad 1173 by IGM Resins B.V.; 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone sold under the name Omnirad 2959 by IGM Resins B.V.; oligo-[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)-phenyl]-propanone] sold under the name Omnirad 127 by IGM Resins B.V. hydroxyacetophenones such as 1,1′-(methylene-di-4,1-phenylene)bis[2-hydroxy-2-methyl-1-propanone] sold by IGM Resins B.V. under the name Omnirad 907; 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-propan-1-one sold by IGM Resins B.V. under the name Omnirad 379EG; and 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, 2-benzyl-2-dimethylamino-1-(3,4-dimethoxy-phenyl)-butan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholin-4-yl-phenyl)-butan-1-one, Omnirad 369 sold by IGM RESINS B.V. aminoacetophenones such as 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone and 2-methyl-1-(4-methylsulfanyl-phenyl)-2-morpholin-4-yl-propan-1-one, sold by Aerosol Products, Inc.; 2,2-dimethoxy-2-phenylacetophenone, 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, 4-t-butyltrichloroacetophenone, and combinations thereof.

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

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

[0069] In particular, the photopolymerization initiator may include an oxyethoxyphenylacetyl derivative, which also corresponds to an intramolecular hydrogen abstraction type photopolymerization initiator. Specific examples of oxyethoxyphenylacetyl derivatives include a blend of oxy-phenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]-ethyl ester and oxy-phenyl-acetic acid 2-[2-hydroxy-ethoxy]-ethyl ester, sold by IGM RESINS B.V. under the name Omnirad 754, and mixtures thereof.

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

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

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

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

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

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

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

[0077] In a particularly preferred embodiment, (C-2) the photoinitiator comprising a combination of α-hydroxyacetophenone and α-aminoalkylphenone consists solely of α-hydroxyacetophenone and α-aminoalkylphenone and does not contain any other photoinitiators, or the amount of other photoinitiators 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] (C-3) Examples of the monoacylphosphine oxide in the combination of α-hydroxyacetophenone and monoacylphosphine oxide include 2,4,6-trimethylbenzoyl)-diphenyl-phosphine oxide (manufactured by IGM Resins B.V., product name: Omnirad TPO-H) and phenyl-(2,4,6-trimethylbenzoyl)-phosphinic acid ethyl ester (manufactured by IGM Resins B.V., product name: Omnirad TPO-L).

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

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

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

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

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

[0084] The (C) photopolymerization initiator may be contained in an amount of 0.001% 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, based on the total mass of the composition, and may be contained 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 Inhibitor and / or Antioxidant The photocurable silicone composition according to the present invention contains either or both of at least one photopolymerization inhibitor as component (d-1) and / or at least one antioxidant as component (d-2).

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0107]

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

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

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

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

[0112] The antioxidant (d-2) may be contained 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, based on the total mass of the composition, and may be contained 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% by mass or less.

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

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

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

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

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

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

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

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

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

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

[0123] In one embodiment of the present invention, component (E) may include, as component (E-1), a resin-like alkenyl group-containing organopolysiloxane. The resin-like alkenyl group-containing organopolysiloxane (E-1) is preferably represented by the average unit formula (III-a): (R ４ ３ SiO １／２ ) ａ (R ４ ２ SiO ２／２ ) ｂ (R ４ SiO ３／２ ) ｃ (SiO ４／２ ) ｄ (XO １／２ ) ｅ (In formula (III-a), R４ are the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups, provided that at least two R ４ is an alkenyl group, 0≦a<1, 0≦b<1, 0≦c<0.9, 0≦d<0.5, and 0≦e<0.4, a+b+c+d=1.0, and c+d>0.

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

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

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

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

[0128] In a preferred embodiment of the present invention, the resin-like alkenyl group-containing organopolysiloxane of component (E-1) contains alkenyl groups at the molecular terminals. The resin-like organopolysiloxane of component (E-1) preferably contains R ３ -SiO １／２ The siloxane unit (M unit) has an alkenyl group on the molecular chain side chain (i.e., R ２ -SiO ２／２ Siloxane units (D units) represented by the formula: and R—SiO ３／２The siloxane units (T units) represented by the following formula (I) may or may not contain an alkenyl group, but preferably do not contain an alkenyl group.

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

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

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

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

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

[0134] Specific examples of the MDT resin of component (E-1) include those having the average structural formula: (Vi(Me ３ ) ２ SiO １／２ ) １５ ((Me ３ ) ２ SiO ２／２ ) ３５ (PhSiO ３／２ ) ５０ Here, Vi represents a vinyl group, Me represents a methyl group, and Ph represents a phenyl group.

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

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

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

[0138] Examples of such component (E-2) include dimethylpolysiloxanes terminally blocked with dimethylvinylsiloxy groups, dimethylpolysiloxanes terminally blocked with diphenylvinylsiloxy groups, dimethylsiloxane-methylphenylsiloxane copolymers terminally blocked with dimethylvinylsiloxy groups, dimethylsiloxane-diphenylsiloxane copolymers terminally blocked with dimethylvinylsiloxy groups, dimethylsiloxane-methylphenylsiloxane copolymers terminally blocked with diphenylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymers terminally blocked with dimethylvinylsiloxy groups, and dimethylsiloxane-methylvinylsiloxane copolymers terminally blocked with dimethylvinylsiloxy groups. Examples include a dimethylsiloxane-methylphenylsiloxane-methylvinylsiloxane copolymer capped with dimethylvinylsiloxy groups, a dimethylsiloxane-diphenylsiloxane-methylvinylsiloxane copolymer capped at both molecular chain terminals with dimethylvinylsiloxy groups, a methylvinylpolysiloxane capped at both molecular chain terminals with trimethylsiloxy groups, a methylvinylsiloxane-methylphenylsiloxane copolymer capped at both molecular chain terminals with trimethylsiloxy groups, a methylvinylsiloxane-diphenylsiloxane copolymer capped at both molecular chain terminals with trimethylsiloxy groups, and a dimethylsiloxane-methylvinylsiloxane copolymer capped at both molecular chain terminals with trimethylsiloxy groups.

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

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

[0141] When the linear organopolysiloxane of component (E-2) contains aryl groups, the content (mol % of aryl groups relative to all silicon-bonded functional groups in the linear organopolysiloxane) can be designed as desired, but is usually 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. The aryl group content can be determined, for example, by analysis using a Fourier transform infrared spectrophotometer (FT-IR), nuclear magnetic resonance (NMR), or the like.

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

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

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

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

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

[0147] In a preferred embodiment of the present invention, the epoxy group-containing resinous organopolysiloxane is one in which h is greater than 0 in the above formula (III-c), that is, R—SiO ３／２ The epoxy group-containing resinous organopolysiloxane of component (E-3) contains siloxane units (T units) represented by the following formula: ４／２ The siloxane unit (Q unit) represented by the following formula (1) may or may not be contained, but preferably is not contained.

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

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

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

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

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

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

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

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

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

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

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

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

[0160] The curable silicone composition according to the present invention is photocurable, and specifically, can be cured by irradiation with active energy rays (e.g., ultraviolet light). Therefore, in one embodiment of the present invention, the photocurable silicone composition according to the present invention is a UV-curable silicone composition. The wavelength of the ultraviolet light to be irradiated is not particularly limited, but is preferably in the range of 360 nm to 395 nm. The irradiation intensity is 500 to 1500 J / cm. ２For example, ultraviolet light (wavelength 365 nm, 1000 J / cm) from a metal halide lamp can be used. ２ The photocurable silicone composition can be cured by irradiating the composition with light. There are no particular restrictions on the irradiation time, but it is usually in the range of 1 to 60 seconds, preferably 5 to 30 seconds, and more preferably 10 to 20 seconds.

[0161] The photocurable silicone composition according to the present invention can be cured to form a cured product with good transparency. Specifically, the cured product of the curable silicone composition according to the present invention preferably has a light transmittance of 90% or more at wavelengths of 400 nm to 700 nm, measured on a sample with a thickness of 1 mm. The light transmittance of the cured product of the curable 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 of the present invention can be cured to form a cured product with high hardness. Preferably, the cured product obtained by curing the photocurable silicone composition of the present invention has a Type A durometer hardness of A50 or greater at 25°C. This Type A durometer hardness is determined using a Type A durometer in accordance with JIS K 6253-1997.

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

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

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

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

[0167] [Encapsulant and Sheet Film] The present invention also relates to an encapsulant or sheet film obtained by curing the photocurable silicone composition of the present invention. The encapsulant of the present invention is suitable for use in encapsulating optical semiconductor elements, including optical semiconductors. The sheet film of the present invention is suitable for use as an encapsulant layer or a pressure-sensitive adhesive sheet film for mass transfer.

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

[0169] The sealing material or sheet film of the present invention can be obtained, for example, by applying the photocurable silicone composition of the present invention to a film-, tape-, or sheet-like substrate, and then curing the composition by irradiating it with active energy rays (e.g., ultraviolet rays) to form a cured coating on the surface of the substrate. There are no particular restrictions on the thickness of the cured coating, but it is preferably in the range of 1 μm to 10 mm, or 5 μm to 5 mm.

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

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

[0172] The photocurable silicone composition of the present invention will be described in more detail with reference to examples and comparative examples. In the examples and comparative examples, the following components were used to prepare the photocurable silicone composition. In the formulation, Vi represents a vinyl group, Me represents a methyl group, Ph represents a phenyl group, Ep represents an epoxy group-containing organic group, and SH represents a thiol group (HSCH ２ CH ２ CH ２ -groups). The numerical values ​​representing amounts in the table are based on the "parts by mass" of the active ingredient in the raw material. The structure of the organopolysiloxane component is shown in a simplified form in the table, with the functional groups other than Me in the M, D, or T units shown in parentheses. SH / Vi indicates the molar ratio of silicon-bonded thiol groups (SH) to vinyl groups (Vi) in the organopolysiloxane component.

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

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

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

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

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

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

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

[0180] (Die shear strength) The obtained photocurable composition was uniformly applied to a glass plate. Next, another glass plate was placed on the composition, and the composition was exposed to UV irradiation (365 nm, 200 mW / cm) from a metal halide lamp. ２ ) to obtain a sheet having a thickness of 1 mm. The die shear strength was measured using a die shear tester (DAGE 4000 Bond Tester manufactured by Nordson DAGE). Samples having a die shear strength of 2 MPa or more were evaluated as "OK."

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

[0182]

[0183]

[0184]

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

[0186] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible within the scope of the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the scope of the appended claims.

Claims

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

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

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

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

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

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

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

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

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

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