Curable silicone composition

Abstract

To provide a curable silicone composition which can be cured at low temperatures and in a short time, has low volumetric shrinkage during curing, has excellent transparency even after heating and can form a cured product having excellent adhesive strength.SOLUTION: There is provided a curable silicone composition which comprises (A) an MQ resinous alkenyl group-containing organopolysiloxane having at least two alkenyl groups per molecule, (B) a resinous organohydrogenepolysiloxane having at least two silicon atom-bonded hydrogen atoms per molecule, (C) a linear organohydrogenpolysiloxane having at least two silicon atom-bonded hydrogen atoms per molecule and (D) a curing catalyst, wherein the content of the resinous organohydrogenepolysiloxane (B) is 5 mass% or more based on the total mass of the composition, the total content of the resinous organohydrogenepolysiloxane (B) and the linear organohydrogenpolysiloxane (C) is 13 mass% or more based on the total mass of the composition and the mass ratio of the content of the resinous organohydrogenepolysiloxane (B) to the content of the linear organohydrogenpolysiloxane (C) is 0.8 or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a curable silicone composition, and more specifically to a curable silicone composition that is suitable for use as an encapsulant for optical semiconductor devices. [Background technology]

[0002] Curable silicone compositions are used in a wide range of industrial fields because they cure to form cured products that have excellent heat resistance, cold resistance, electrical insulation, weather resistance, water resistance, and transparency. In particular, the cured products are less likely to discolor than other organic materials, and the deterioration of physical properties such as durability is small, so they are widely used as silicone encapsulants for optical materials, especially for optical semiconductor devices such as light-emitting diodes (LEDs).

[0003] For example, Japanese Patent Laid-Open Publication No. 2010-174233 (Patent Document 1) describes a curable silicone rubber composition that includes an alkenyl group-containing dialkyl polysiloxane, a resin-like alkenyl group-containing organo polysiloxane, an organo polysiloxane having silicon atom-bonded hydrogen atoms and SiO4 / 2 units, a linear organo polysiloxane having silicon atom-bonded hydrogen atoms, and a catalyst for hydrosilylation reaction. The examples of Patent Document 1 describe that the curable silicone rubber composition was press-cured at 120°C for 10 minutes and further treated at 200°C for 4 hours.

[0004] Patent Document 2 also describes that a curable silicone resin composition containing a linear organopolysiloxane having two or more alkenyl groups, a branched organopolysiloxane having two or more alkenyl groups, a branched organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms, a linear organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms, and a catalyst is used as a die attach material for optical semiconductor devices.

[0005] Furthermore, Patent Document 3 describes that an addition-curable silicone resin composition containing a linear organopolysiloxane having two or more alkenyl groups, a branched organopolysiloxane having two or more alkenyl groups, a branched organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms, and an addition reaction catalyst is used as a die attach material for optical semiconductor devices.

[0006] Patent Document 4 describes a silicone resin composition for lens molding that contains an organopolysiloxane having two or more aliphatic unsaturated bonds in one molecule, a branched organohydrogenpolysiloxane having three or more hydrogen atoms bonded to silicon atoms in one molecule, and a platinum group metal catalyst. The examples in Patent Document 4 describe molding the silicone resin composition for lens molding at 150°C for 90 seconds.

[0007] Patent Document 5 describes a linear organopolysiloxane having at least two silicon-bonded alkenyl groups in one molecule, and at least 5 mol % of all silicon-bonded organic groups being aryl groups; 1 3 SiO 1 / 2 (In the formula, R 1 are the same or different monovalent hydrocarbon groups.) and a siloxane unit represented by the formula: SiO 4 / 2It is described that an optical semiconductor element is sealed with a cured product of a curable silicone composition comprising at least an organopolysiloxane having siloxane units represented by the formula (I) and an alkenyl group content of at least 6% by weight; an organopolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule; and a catalyst for hydrosilylation reaction. Comparative Example 5 of Patent Document 5 describes a composition containing 88% by weight of a linear organopolysiloxane having at least two alkenyl groups and having no aryl groups as all silicon-bonded organic groups, 5.1% by weight of a vinyl-containing organopolysiloxane MQ resin, 6.1% by weight of an organohydrogenpolysiloxane MQ resin, and 0.5% by weight of a condensation reaction product of a methylvinylsiloxane oligomer blocked with silanol groups at both ends of the molecular chain and 3-glycidoxypropyltrimethoxysilane, based on the total weight of the polysiloxane that can participate in the hydrosilylation reaction.

[0008] Patent Document 6 describes coating a light-emitting element with a cured product of an addition-curable silicone composition that contains an organopolysiloxane having a network structure having at least two alkenyl groups in one molecule, a linear organopolysiloxane having at least two alkenyl groups in one molecule, a branched organohydrogenpolysiloxane having at least two hydrosilyl groups in one molecule, a linear organohydrogenpolysiloxane having at least two hydrosilyl groups in one molecule, and a hydrosilylation catalyst.

[0009] Furthermore, Patent Document 7 describes sealing an optical semiconductor with a curable organopolysiloxane composition containing an organopolysiloxane having an alkenyl group and an aryl group, an organohydrogenpolysiloxane, and an addition reaction catalyst.

[0010] Patent Document 8 describes a linear organopolysiloxane having at least two alkenyl groups in one molecule, an organohydrogenpolysiloxane consisting only of M units, D units, and T units, and a thermally conductive silicone composition containing the linear organohydrogenpolysiloxane. Comparative Example 3 of JP-A-10-231428 (Patent Document 9) describes a composition containing 100 parts by weight of a dimethylpolysiloxane in which both molecular chain terminals are blocked with vinyldimethylsilyl groups and 1.6 parts by weight of a branched hydrogenpolysiloxane compound.

[0011] However, in order to form a cured product from a curable silicone composition that cures by a hydrosilylation reaction, it may be necessary to heat cure at a high temperature for a long time. For example, in the examples of the above-mentioned Patent Documents 2, 3, 5, 6, and 7, it is described that the curable silicone composition was cured by heating at 150 ° C for 1 hour or more. This long curing time leads to low productivity. Furthermore, when heating at a high temperature for a long time is required to cure the curable silicone composition, electronic devices such as optical semiconductor elements to which the curable silicone composition is applied may be damaged by heating. For this reason, a curable silicone composition that can be cured at a low temperature and in a short time has been required. One method for curing the curable silicone composition at a low temperature and in a short time is to increase the amount of hydrosilylation catalyst. However, if the amount of hydrosilylation catalyst is increased in the curable silicone composition, the discoloration of the cured product becomes significant, and it may not be possible to use it for applications such as sealing of optical semiconductor elements where transparency of the cured product is required.

[0012] Furthermore, the curable silicone composition cured by hydrosilylation reaction may cause high volume shrinkage during curing. This volume shrinkage may cause warping of the flexible film and poor precision of flatness-thickness control. Furthermore, low viscosity of the curable silicone composition is important for improving process efficiency in processes such as encapsulating optical semiconductor elements with the curable silicone composition. Low viscosity of the curable silicone composition is also important for self-flattening properties required in screen printing processes and the like. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] JP 2010-174233 A [Patent Document 2] JP 2018-131583 A [Patent Document 3] JP 2016-155967 A [Patent Document 4] JP 2006-328102 A [Patent Document 5] International Publication No. 2018 / 062009 [Patent Document 6] JP 2016-204423 A [Patent Document 7] JP 2015-218233 A [Patent Document 8] JP 2009-292928 A Summary of the Invention [Problem to be solved by the invention]

[0014] An object of the present invention is to provide a curable silicone composition that can be cured at low temperatures in a short time, that undergoes little volumetric shrinkage during curing, and that is capable of forming a cured product that has excellent transparency and adhesive strength even after heating. [Means for solving the problem]

[0015]

[0013] In order to solve the above problems, the present inventors conducted extensive research and surprisingly discovered that by combining an MQ resin-like alkenyl group-containing organopolysiloxane with a specific organohydrogenpolysiloxane, a curing reaction can be carried out at a low temperature in a short time to form a cured product that has little volumetric shrinkage during curing and excellent adhesive strength, thereby completing the present invention.

[0016] Thus, the present invention provides (A) an MQ resinous alkenyl-containing organopolysiloxane having at least two alkenyl groups per molecule; (B) a resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; (C) a linear organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; (D) Curing catalyst A curable silicone composition comprising: (B) the content of the resinous organohydrogenpolysiloxane is 5% by mass or more based on the total mass of the composition; the total content of the resinous organohydrogenpolysiloxane (B) and the linear organohydrogenpolysiloxane (C) is 13 mass% or more based on the total mass of the composition; the mass ratio of the content of the resinous organohydrogenpolysiloxane (B) to the content of the linear organohydrogenpolysiloxane (C) is 0.8 or more; The present invention relates to a curable silicone composition.

[0017] The content of (A) the MQ resin-like alkenyl group-containing organopolysiloxane is preferably from 30% by mass to 80% by mass.

[0018] (B) The resinous organohydrogenpolysiloxane preferably has a network-like molecular structure.

[0019] (B) The resin-like organohydrogenpolysiloxane preferably contains an MQ resin-like organohydrogenpolysiloxane and / or a resin-like organohydrogenpolysiloxane consisting only of M units and T units.

[0020] The mass ratio of the content of the resinous organohydrogenpolysiloxane (B) to the content of the linear organohydrogenpolysiloxane (C) is preferably 3 or less.

[0021] The present invention also relates to a semiconductor encapsulant formed from the curable silicone composition of the present invention.

[0022] The present invention also relates to an optical semiconductor device comprising the semiconductor encapsulant according to the present invention. Effect of the Invention

[0023] The curable silicone composition according to the present invention can be cured at low temperatures in a short time, undergoes little volumetric shrinkage during curing, and forms a cured product that has excellent transparency and adhesive strength even after heating. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] [Curable Silicone Composition] The curable silicone composition according to the present invention comprises: (A) an MQ resinous alkenyl-containing organopolysiloxane having at least two alkenyl groups per molecule; (B) a resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; (C) a linear organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; (D) Curing catalyst Including, (B) the content of the resinous organohydrogenpolysiloxane is 5% by mass or more based on the total mass of the composition; the total content of the resinous organohydrogenpolysiloxane (B) and the linear organohydrogenpolysiloxane (C) is 13 mass% or more based on the total mass of the composition; The mass ratio of the content of the resinous organohydrogenpolysiloxane (B) to the content of the linear organohydrogenpolysiloxane (C) is 0.8 or more.

[0025] Each component of the curable silicone composition of the present invention will now be described in detail.

[0026] (A) MQ resin-like alkenyl-containing organopolysiloxane having at least two alkenyl groups per molecule Component (A) is a curable organopolysiloxane having at least two alkenyl groups in one molecule. The curable silicone composition according to the present invention may contain one type of (A) MQ resin-like alkenyl-group-containing organopolysiloxane, or may contain two or more types of (A) MQ resin-like alkenyl-group-containing organopolysiloxane.

[0027] The molecular structure of component (A) is MQ resin-like. In this specification, resin-like means branched or network-like, and network-like is preferred. MQ resin is R 3 SiO 1 / 2 Siloxane units (M units) represented by the formula: and SiO 4 / 2 It means a resin-like organopolysiloxane consisting only of siloxane units (Q units) represented by the following formula: In addition, R in the siloxane unit represents a silicon-bonded organic group.

[0028] Examples of the alkenyl group contained in component (A) include alkenyl groups having 2 to 12 carbon atoms, such as vinyl groups, allyl groups, butenyl groups, pentenyl groups, hexenyl groups, heptenyl groups, octenyl groups, nonenyl groups, decenyl groups, undecenyl groups, and dodecenyl groups, with vinyl groups being preferred.

[0029] Examples of the group bonded to the silicon atom other than the alkenyl group contained in the component (A) include halogen-substituted or unsubstituted monovalent hydrocarbon groups other than the alkenyl group. For example, alkyl groups having 1 to 12 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group; aryl groups having 6 to 20 carbon atoms such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl groups having 7 to 20 carbon atoms such as benzyl group, phenethyl group, phenylpropyl group; and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine atom, chlorine atom, bromine atom. In addition, the silicon atom in the component (A) may have a small amount of hydroxyl group, alkoxy groups such as methoxy group and ethoxy group, as long as the object of the present invention is not impaired. The group bonded to the silicon atom other than the alkenyl group in the component (A) is preferably selected from alkyl groups having 1 to 6 carbon atoms, particularly the methyl group.

[0030] The MQ resin-like alkenyl group-containing organopolysiloxane of the component (A) can preferably be represented by the following average unit formula (I). Average unit formula (I): (R 1 3 SiO 1 / 2 ) s (SiO 4 / 2 ) t (XO 1 / 2 ) u In the formula, R 1 is the same or different halogen-substituted or unsubstituted monovalent hydrocarbon group, provided that at least two R 1 in one molecule are alkenyl groups, 0 < s < 1, 0 < t < 1, 0 ≤ u < 0.4, and s + t = 1.0, and u represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms) when the total number of silicon atoms is 1.

[0031] R 1Examples of halogen-substituted or unsubstituted monovalent hydrocarbon groups 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; aryl groups having 6 to 20 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl groups; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, phenethyl, and phenylpropyl 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, or bromine atoms. R 1 R 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 selected from an alkyl group having 1 to 6 carbon atoms, particularly a methyl group, and an alkenyl group having 2 to 6 carbon atoms, particularly a vinyl group.

[0032] In the above formula (I), 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, and specific examples thereof include a methyl group, an ethyl group, and a propyl group. X is preferably a hydrogen atom.

[0033] In formula (I), s is preferably in the range of 0.2≦s≦0.8, more preferably in the range of 0.3≦s≦0.7, and even more preferably in the range of 0.4≦s≦0.6. In formula (I), t is preferably in the range of 0.2≦t≦0.8, more preferably in the range of 0.3≦t≦0.7, and particularly in the range of 0.4≦t≦0.6. In formula (I), u is preferably in the range of 0≦u≦0.15, more preferably in the range of 0≦u≦0.1, and particularly in the range of 0≦u≦0.05.

[0034] The alkenyl group content of the entire silicon-bonded organic groups in the MQ resin-like alkenyl group-containing organopolysiloxane of component (A) is not particularly limited, but may be, for example, 1 mol% or more, preferably 2 mol% or more, more preferably 3 mol% or more of the total silicon-bonded organic groups, and 20 mol% or less, preferably 15 mol% or more, more preferably 10 mol% or less of the total silicon-bonded organic groups. The alkenyl group content can be determined, for example, by an analytical method such as Fourier transform infrared spectrophotometer (FT-IR) or nuclear magnetic resonance (NMR), or by the titration method described below. In this specification, the upper and lower limit values ​​of the numerical values ​​can be arbitrarily combined to set an appropriate numerical range.

[0035] This section explains how to quantify the amount of alkenyl groups in each component by titration. The alkenyl group content in organopolysiloxane components can be accurately quantified by a titration method commonly known as the Wyss method. The principle is as follows. First, alkenyl groups in the organopolysiloxane raw material are subjected to an addition reaction with iodine monochloride as shown in formula (1). Next, excess iodine monochloride is reacted with potassium iodide and liberated as iodine by the reaction shown in formula (2). The liberated iodine is then titrated with a sodium thiosulfate solution. Formula (1) CH 2 =CH- + 2ICl → CH 2 I-CHCl- + ICl (excess) Equation (2) ICl + KI → I 2 + KCl The amount of alkenyl groups in the component can be quantified from the difference between the amount of sodium thiosulfate required for titration and the amount of a blank solution prepared separately.

[0036] The content of aryl groups in the total silicon-bonded organic groups of the MQ resin-like alkenyl-containing organopolysiloxane of component (A) is not particularly limited, but may be, for example, 20 mol% or less, preferably 10 mol%, more preferably 5 mol% or less of the total silicon-bonded organic groups. In one embodiment of the present invention, the MQ resin-like alkenyl-containing organopolysiloxane of component (A) does not contain aryl groups as silicon-bonded organic groups. The content of aryl groups can be determined by, for example, an analysis method such as Fourier transform infrared spectrophotometer (FT-IR) or nuclear magnetic resonance (NMR).

[0037] The viscosity of the MQ resin-like alkenyl-containing organopolysiloxane (A) is not particularly limited. For example, the component (A) is solid at 25°C. For example, the component (A) has a viscosity in the range of 1 to 200,000 mPa·s at 25°C, and more preferably in the range of 5 to 100,000 mPa·s. In this specification, the viscosity of the organopolysiloxane component can be measured with a rotational viscometer in accordance with JIS K7117-1.

[0038] The number average molecular weight of the (A) MQ resin-like alkenyl group-containing organopolysiloxane is not particularly limited, but may be, for example, at least 1,000, preferably at least 1,500, and usually at most 200,000, preferably at most 150,000, and more preferably at most 100,000. In this specification, the number average molecular weight (Mn) and weight average molecular weight (Mw) are values ​​calculated in terms of standard polystyrene measured by gel permeation chromatography (GPC).

[0039] (A) The siloxane units (SiO x / 2 The number of ) is not particularly limited, but is, for example, 5 to 2000, and preferably 10 to 1000.

[0040] The content of (A) MQ resin-like alkenyl-group-containing organopolysiloxane is not particularly limited, but is usually 30 mass% or more, more preferably 40 mass% or more, and even more preferably 50 mass% or more, based on the total mass of the curable silicone composition of the present invention. The content of component (A) is usually 80 mass% or less, preferably 70 mass% or less, and even more preferably 60 mass% or less, based on the total mass of the curable silicone composition of the present invention.

[0041] (B) a resin-like organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; Component (B) acts as a crosslinking agent for the curable silicone composition through a hydrosilylation curing reaction, and is a resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule. The curable silicone composition according to the present invention may contain one type of resinous organohydrogenpolysiloxane (B), or may contain two or more types of resinous organohydrogenpolysiloxane (B).

[0042] Examples of groups bonded to silicon atoms other than silicon-bonded hydrogen atoms contained in component (B) include halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups, such as 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; 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. The silicon atoms in component (B) may contain small amounts of hydroxyl groups or alkoxy groups, such as methoxy and ethoxy, as long as the object of the present invention is not impaired. Groups bonded to silicon atoms in component (B) other than silicon-bonded hydrogen atoms are preferably selected from alkyl groups having 1 to 6 carbon atoms, particularly methyl groups.

[0043] In one embodiment of the present invention, the resinous organohydrogenpolysiloxane of component (B) can be preferably represented by the following average unit formula (II): Average unit formula (II): (R 2 3 SiO 1 / 2 ) a (R 2 2 SiO 2 / 2 ) b (R 2 SiO 3 / 2 ) c (SiO 4 / 2 ) d (XO 1 / 2 ) e In formula (II), R 2 are each independently a hydrogen atom or the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups, provided that at least two R 2is a hydrogen atom, 0≦a<1, 0≦b<1, 0≦c<0.9, 0≦d<0.7, and 0≦e<0.4, a+b+c+d=1.0, and c+d>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).

[0044] R in the above formula (II) 2 Examples of the halogen-substituted or unsubstituted monovalent hydrocarbon group other than an alkenyl group of R 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; aryl groups having 6 to 20 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl groups; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, phenethyl, and phenylpropyl 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. 2 R 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. 2 is preferably selected from a hydrogen atom and an alkyl group having 1 to 6 carbon atoms, in particular a methyl group.

[0045] In the above formula (II), 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, and specific examples thereof include a methyl group, an ethyl group, and a propyl group. X is preferably a hydrogen atom.

[0046] In the above formula (II), a is preferably in the range of 0.1≦a≦0.9, more preferably in the range of 0.3≦a≦0.8, and even more preferably in the range of 0.5≦a≦0.7. In the above formula (II), 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 (II), c is preferably in the range of 0.1≦c≦0.7, more preferably in the range of 0.2≦c≦0.6, and particularly in the range of 0.3≦c≦0.5. In the above formula (II), d is preferably in the range of 0≦d≦0.7, more preferably in the range of 0≦d≦0.6, and particularly in the range of 0≦d≦0.5. In the above formula (II), e is preferably in the range of 0≦e≦0.15, more preferably in the range of 0≦e≦0.1, and particularly in the range of 0≦e≦0.05.

[0047] In a preferred embodiment of the present invention, R 2 SiO 1 / 2 It may or may not contain a siloxane unit (D unit) represented by the following formula: but preferably it does not contain one.

[0048] In a preferred embodiment of the present invention, the resinous organohydrogenpolysiloxane of component (B) contains silicon-bonded hydrogen atoms at the molecular terminals. The resinous organohydrogenpolysiloxane of component (B) preferably has silicon-bonded hydrogen atoms in the M units and may or may not contain silicon-bonded hydrogen atoms in the molecular chain side chains (i.e., D units and T units), but preferably does not contain them.

[0049] In a preferred embodiment of the present invention, the resinous organohydrogenpolysiloxane of component (B) may or may not contain an aryl group in the silicon-bonded organic group. The aryl group may be an aryl group having 6 to 20 carbon atoms, such as a phenyl group, a tolyl group, a xylyl group, or a naphthyl group, with a phenyl group being particularly preferred.

[0050] When the resinous organohydrogenpolysiloxane of component (B) contains an aryl group, its content (mol% of the aryl group in all the silicon atom-bonded functional groups of the resinous organohydrogenpolysiloxane) can be designed as desired, but is usually 5 mol% or more, preferably 10 mol% or more, more preferably 15 mol% or more, and can be 50 mol% or less, preferably 40 mol% or less, more preferably 30 mol% or less.

[0051] In another embodiment of the present invention, the resinous organohydrogenpolysiloxane of component (B) does not contain an aryl group in the silicon atom-bonded organic group, or contains it in an amount of 15 mol% or less, 10 mol% or more, or 5 mol% or more based on all the silicon atom-bonded functional groups.

[0052] In one embodiment of the present invention, the resinous organohydrogenpolysiloxane of component (B) contains an MQ resinous organohydrogenpolysiloxane. The MQ resinous organohydrogenpolysiloxane can preferably be represented by the following average unit formula (II-a). Average unit formula (II-a): (R 2 3 SiO 1 / 2 ) s (SiO 4 / 2 ) t (XO 1 / 2 ) u In the formula, each R 2 is independently a halogen-substituted or unsubstituted monovalent hydrocarbon group other than a hydrogen atom or the same or different alkenyl groups, provided that in one molecule, at least two R 2 are hydrogen atoms, 0 < s < 1, 0 < t < 1, 0 ≤ u < 0.4, and s + t = 1.0, and u represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms) when the total number of silicon atoms is 1.

[0053] R 2 and X in the above formula (II-a) are as defined in the above formula (II), and the same explanation applies.

[0054] In formula (II-a), s is preferably in the range of 0.3 ≤ s ≤ 0.9, more preferably in the range of 0.4 ≤ s ≤ 0.8, and even more preferably in the range of 0.5 ≤ s ≤ 0.7. In the above formula (II-a), t is preferably in the range of 0.1 ≤ t ≤ 0.7, more preferably in the range of 0.2 ≤ t ≤ 0.6, and particularly in the range of 0.3 ≤ t ≤ 0.5. In formula (II-a), u is preferably in the range of 0 ≤ u ≤ 0.15, more preferably in the range of 0 ≤ u ≤ 0.1, and particularly in the range of 0 ≤ u ≤ 0.05.

[0055] In one embodiment of the present invention, the MQ resin-like organohydrogenpolysiloxane as component (B) does not contain an aryl group in the silicon atom-bonded organic group, or contains it in an amount of 15 mol% or less, 10 mol% or more, or 5 mol% or more based on the whole silicon atom-bonded functional group.

[0056] In one embodiment of the present invention, the resin-like organohydrogenpolysiloxane as component (B) includes a resin-like organohydrogenpolysiloxane composed only of M units and T units. The resin-like organohydrogenpolysiloxane composed only of M units and T units can preferably be represented by the following average unit formula (II-b). Average unit formula (II-b): (R 2 3 SiO 1 / 2 ) s (R 2 SiO 3 / 2 ) t (XO 1 / 2 ) u In the formula, each R 2 is independently a halogen-substituted or unsubstituted monovalent hydrocarbon group other than a hydrogen atom or the same or different alkenyl groups, provided that in one molecule, at least two R 2 are hydrogen atoms, 0 < s < 1, 0 < t < 1, 0 ≤ u < 0.4, and s + t = 1.0, and u represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms) when the total number of silicon atoms is 1.

[0057] R in the above formula (II-b) 2 and X is as defined above in formula (II).

[0058] In formula (II-b), s is preferably in the range of 0.3≦s≦0.9, more preferably in the range of 0.4≦s≦0.8, and even more preferably in the range of 0.5≦s≦0.7. In formula (II-b), t is preferably in the range of 0.1≦t≦0.7, more preferably in the range of 0.2≦t≦0.6, and particularly in the range of 0.3≦t≦0.5. In formula (II-b), u is preferably in the range of 0≦u≦0.15, more preferably in the range of 0≦u≦0.1, and particularly in the range of 0≦u≦0.05.

[0059] In one embodiment of the present invention, the resin-like organohydrogenpolysiloxane consisting only of M units and T units as component (B) may contain aryl groups in the silicon-bonded organic groups. In that case, the content (the aryl group mol % relative to all silicon-bonded functional groups in the resin-like organohydrogenpolysiloxane) can be designed as desired, but is usually 5 mol % or more, preferably 10 mol % or more, and more preferably 15 mol % or more, and can be 50 mol % or less, preferably 40 mol % or less, and more preferably 30 mol % or less.

[0060] The viscosity of the resinous organohydrogenpolysiloxane of component (B) is not particularly limited, but is, for example, within the range of 10 mPa to 1000 mPa at 25° C. In this specification, the viscosity of the organopolysiloxane component can be measured at 25° C. using a rotational viscometer in accordance with JIS K7117-1.

[0061] In one embodiment of the present invention, the number average molecular weight (Mn) of the resinous organohydrogenpolysiloxane of component (B) is preferably within the range of 500 to 3000, and more preferably within the range of 600 to 2000. In one embodiment of the present invention, the weight average molecular weight (Mw) of the resinous organohydrogenpolysiloxane of component (B) is preferably within the range of 500 to 3000, and more preferably within the range of 600 to 2000.

[0062] The content of the resinous organohydrogenpolysiloxane of component (B) is 5 mass% or more based on the total mass of the curable silicone composition of the present invention. Also, the content of component (B) is usually 30 mass% or less, preferably 20 mass% or less, and more preferably 15 mass% or less based on the total mass of the curable silicone composition of the present invention.

[0063] (C) a linear organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; Like component (B), component (C) acts as a crosslinking agent for the curable silicone composition by a hydrosilylation curing reaction, and is a linear organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule. The curable silicone composition according to the present invention may contain one type of linear organohydrogenpolysiloxane (C), or may contain two or more types of linear organohydrogenpolysiloxane (C).

[0064] Examples of groups bonded to silicon atoms other than silicon-bonded hydrogen atoms contained in component (C) include halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups, such as 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; 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. The silicon atoms in component (C) may contain small amounts of hydroxyl groups or alkoxy groups, such as methoxy and ethoxy, as long as the object of the present invention is not impaired. Groups bonded to silicon atoms in component (C) other than silicon-bonded hydrogen atoms are preferably selected from alkyl groups having 1 to 6 carbon atoms, particularly methyl groups.

[0065] In one embodiment of the present invention, the component (C) is preferably Average structural formula (III):R 2 3 SiO(R 2 2 SiO 2 / 2 ) n SiR 2 3 (In formula (III), R 2 are hydrogen atoms or the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups, provided that at least two R 2 is a hydrogen atom, and n is 1 to 200).

[0066] In the above formula (III), R 2 The halogen-substituted or unsubstituted monovalent hydrocarbon group other than the alkenyl group is as defined in the above formula (II), and the same explanation can be applied.

[0067] In the above formula (III), n is preferably 1 to 100, and more preferably 1 to 50. In another embodiment, the number of siloxane units contained in the component (C) is usually 3 to 200, preferably 3 to 100, and more preferably 3 to 50.

[0068] In a preferred embodiment of the present invention, the linear organohydrogenpolysiloxane of component (C) contains silicon-bonded hydrogen atoms at both molecular chain terminals. The linear organohydrogenpolysiloxane of component (C) has silicon-bonded hydrogen atoms in the M units, and the D units may or may not contain silicon-bonded hydrogen atoms, but preferably do not.

[0069] In one embodiment, component (C) may or may not contain an aryl group in the silicon-bonded organic group. The aryl group may be an aryl group having 6 to 20 carbon atoms, such as a phenyl group, a tolyl group, a xylyl group, or a naphthyl group, and is particularly preferably a phenyl group.

[0070] When the linear organohydrogenpolysiloxane of component (C) contains aryl groups, the content thereof (the mole % of aryl groups relative to all silicon-bonded functional groups in the linear organohydrogenpolysiloxane) can be designed as desired, but is usually at least 5 mol %, preferably at least 10 mol %, and more preferably at least 15 mol %, and can be no more than 50 mol %, preferably no more than 40 mol %, and more preferably no more than 30 mol %.

[0071] The content of component (C) is not particularly limited, but is preferably 1 mass% or more, more preferably 3 mass% or more, and even more preferably 5 mass% or more, based on the total mass of the curable silicone composition. Also, component (C) is usually contained in an amount of 20 mass% or less, preferably 15 mass% or less, and more preferably 10 mass% or less, based on the total mass of the curable silicone composition.

[0072] In the present invention, the total content of (B) resin-like organohydrogenpolysiloxane and (C) linear organohydrogenpolysiloxane is 13 mass% or more based on the total mass of the curable silicone composition of the present invention.In addition, the mass ratio of the content of (B) resin-like organohydrogenpolysiloxane to the content of (C) linear organohydrogenpolysiloxane is 0.8 or more, preferably 0.85 or more.In addition, the mass ratio of the content of (B) resin-like organohydrogenpolysiloxane to the content of (C) linear organohydrogenpolysiloxane is usually 3 or less, preferably 2.5 or less, more preferably 2 or less.

[0073] Furthermore, in one embodiment of the present invention, the ratio (H / Al) of silicon-bonded alkenyl groups to silicon-bonded hydrogen atoms contained in the organopolysiloxane component of the present invention is such that, per mole of silicon-bonded alkenyl groups in the curable silicone composition, there are at least 0.7 moles of silicon-bonded hydrogen atoms, preferably at least 0.8 moles, more preferably at least 0.9 moles, and especially at least 0.95 moles; and, for example, per mole of silicon-bonded alkenyl groups in the curable silicone composition, there are at most 3 moles of silicon-bonded hydrogen atoms, preferably at most 2 moles, more preferably at most 1.7 moles, and even more preferably at most 1.6 moles.

[0074] (D) Curing catalyst The curing catalyst of component (D) is a curing catalyst for hydrosilylation reaction, and is a catalyst for promoting the curing of the curable silicone composition of the present invention. Examples of such component (E) include platinum-based catalysts such as chloroplatinic acid, alcohol solution of chloroplatinic acid, complex of platinum and olefin, complex of platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, and powder carrying platinum; palladium-based catalysts such as tetrakis(triphenylphosphine)palladium, palladium black, and mixture with triphenylphosphine; and rhodium-based catalysts, and particularly, platinum-based catalysts are preferred.

[0075] The amount of component (D) is a catalytic amount. More specifically, when a platinum-based catalyst is used as component (D), the amount of platinum atoms, relative to the total mass of the curable silicone composition of the present invention, is preferably at least 0.01 ppm, more preferably at least 0.1 ppm, and even more preferably at least 1 ppm; and the amount of platinum atoms, relative to the total mass of the curable silicone composition of the present invention, is preferably no more than 20 ppm, more preferably no more than 15 ppm, and even more preferably no more than 10 ppm.

[0076] (Other organopolysiloxane components) The curable silicone composition according to the present invention may contain an organopolysiloxane component other than the components (A) to (C). Examples of such other organopolysiloxane components include linear alkenyl group-containing organopolysiloxanes, organosiloxane oligomers having at least one epoxy group, and cerium-containing organopolysiloxanes.

[0077] The curable silicone composition according to the present invention may contain one or more linear alkenyl-containing organopolysiloxanes. The linear alkenyl-containing organopolysiloxanes may preferably be represented by the following formula (IV): Average structural formula (IV):R 1 3 SiO(R 1 2 SiO 2 / 2 ) m SiR 2 3 In formula (IV), R 1 are the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups, provided that at least two R 1 is an alkenyl group, and m is 1 to 500.

[0078] In the above formula (IV), R 1 The halogen-substituted or unsubstituted monovalent hydrocarbon group may be the same as that in formula (I) above.

[0079] In the above formula (IV), m is preferably 5-300, more preferably 10-250, and further preferably 20-200.

[0080] Examples of such linear alkenyl-containing organopolysiloxanes include dimethylpolysiloxanes capped with dimethylvinylsiloxy groups at both molecular chain terminals, dimethylpolysiloxanes capped with diphenylvinylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylphenylsiloxane copolymers capped with dimethylvinylsiloxy groups at both molecular chain terminals, dimethylsiloxane-diphenylsiloxane copolymers capped with dimethylvinylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylphenylsiloxane copolymers capped with diphenylvinylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylvinylsiloxane copolymers capped with dimethylvinylsiloxy groups at both molecular chain terminals, Examples include dimethylsiloxane-methylphenylsiloxane-methylvinylsiloxane copolymers end-capped with dimethylvinylsiloxy groups, dimethylsiloxane-diphenylsiloxane-methylvinylsiloxane copolymers end-capped with dimethylvinylsiloxy groups at both molecular chain terminals, methylvinylpolysiloxanes end-capped with trimethylsiloxy groups at both molecular chain terminals, methylvinylsiloxane-methylphenylsiloxane copolymers end-capped with trimethylsiloxy groups at both molecular chain terminals, methylvinylsiloxane-diphenylsiloxane copolymers end-capped with trimethylsiloxy groups at both molecular chain terminals, and dimethylsiloxane-methylvinylsiloxane copolymers end-capped with trimethylsiloxy groups at both molecular chain terminals.

[0081] In a preferred embodiment of the present invention, the linear alkenyl group-containing organopolysiloxane may be a linear organopolysiloxane having both molecular chain terminals blocked with alkenyl groups, which contains alkenyl groups at both molecular chain terminals. The linear alkenyl group-containing organopolysiloxane may or may not contain alkenyl groups in the molecular chain side chains (i.e., D units), but preferably does not contain them.

[0082] The content of alkenyl groups contained in the linear alkenyl group-containing organopolysiloxane (mol % of alkenyl groups in the total silicon-bonded functional groups of the linear organopolysiloxane) can be designed as desired, but is usually 1 mol % or more, preferably 2 mol % or more, more preferably 3 mol % or more, and may be 20 mol % or less, preferably 15 mol % or less, more preferably 10 mol % or less. The content of alkenyl groups can be determined, for example, by analysis using a Fourier transform infrared spectrophotometer (FT-IR), nuclear magnetic resonance (NMR), the titration method, or the like.

[0083] In one embodiment, the linear alkenyl group-containing organopolysiloxane may or may not contain an aryl group in the silicon atom-bonded organic group. The aryl group may be an aryl group having 6 to 20 carbon atoms, such as a phenyl group, a tolyl group, a xylyl group, or a naphthyl group, and is particularly preferably a phenyl group. When the linear alkenyl group-containing organopolysiloxane contains an aryl group, the content (mol % of the aryl group in the total silicon atom-bonded functional groups of the alkenyl group-containing organopolysiloxane) can be designed as desired, but is usually 5 mol % or more, preferably 10 mol % or more, more preferably 15 mol % or more, and may be 50 mol % or less, preferably 40 mol % or less, more preferably 30 mol % or less.

[0084] When the curable silicone composition of the present invention contains a linear alkenyl group-containing organopolysiloxane, its content is not particularly limited, but is usually 5 mass% or more, more preferably 10 mass% or more, and even more preferably 20 mass% or more, based on the total mass of the curable silicone composition of the present invention. Also, the content of the linear alkenyl group-containing organopolysiloxane is usually 50 mass% or less, more preferably 40 mass% or less, and even more preferably 35 mass% or less, based on the total mass of the curable silicone composition of the present invention.

[0085] The curable silicone composition according to the present invention may contain one type of organosiloxane oligomer having at least one epoxy group, or may contain a combination of two or more types of organosiloxane oligomers having at least one epoxy group.

[0086] The epoxy group-containing organosiloxane oligomer may contain 2 to 20 siloxane units, preferably 3 to 18 siloxane units, and more preferably 3 to 15 siloxane units.

[0087] The molecular structure of the organosiloxane oligomer having at least one epoxy group may be, for example, a linear structure, a linear structure having some branches, a branched structure, a resin structure, a cyclic structure, or a three-dimensional network structure. In one embodiment, the epoxy group-containing organosiloxane oligomer is an epoxy group-containing resin structure.

[0088] The epoxy group-containing organosiloxane oligomer has at least one epoxy group. Examples of the epoxy group contained in the epoxy group-containing organosiloxane oligomer include glycidoxyalkyl groups such as 2-glycidoxyethyl group, 3-glycidoxypropyl group, and 4-glycidoxybutyl group; epoxycycloalkyl groups such as 2-(3,4-epoxycyclohexyl)-ethyl group and 3-(3,4-epoxycyclohexyl)-propyl group; and epoxyalkyl groups such as 3,4-epoxybutyl group and 7,8-epoxyoctyl group.

[0089] Examples of the silicon-bonded organic groups other than epoxy groups contained in the epoxy group-containing organosiloxane oligomer 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; vinyl, allyl, butenyl, pentenyl, and hexenyl groups. Examples of the organic group bonded to the silicon atom include alkenyl groups having 2 to 12 carbon atoms, such as phenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl groups, preferably vinyl groups; aryl groups having 6 to 12 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl groups; aralkyl groups having 7 to 12 carbon atoms, such as benzyl, phenethyl, and phenylpropyl groups; and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms, such as fluorine, chlorine, and bromine atoms. Preferably, the silicon atom-bonded organic group other than the epoxy group includes an alkyl group having 1 to 12 carbon atoms, particularly a methyl group, and an alkenyl group having 2 to 12 carbon atoms, particularly a vinyl group. The epoxy group-containing organosiloxane oligomer does not need to include a thiol group.

[0090] In one preferred embodiment of the present invention, the epoxy-containing organosiloxane oligomer contains at least one epoxy group and at least one alkenyl group, such as a vinyl group.

[0091] In one embodiment of the present invention, the epoxy group-containing organosiloxane oligomer has the following average unit formula (V): (R 3 3 SiO 2 / 2 ) f (R 3 2 SiO 3 / 2 ) g (SiO 4 / 2 ) h (XO 1 / 2 ) i {In formula (V), R 3 are each independently a halogen-substituted or unsubstituted monovalent hydrocarbon group, provided that at least one R3 is an epoxy group-containing organic group, X is a hydrogen atom or an alkyl group, and is a number that satisfies 0≦f<1, 0≦g<1, 0≦h<0.95, 0≦i<0.4, f+g+h=1.0, and g+h>0. i represents the number of (XO) groups when the total number of silicon atoms is taken as 1 (the ratio of the number of (XO) groups to the total number of silicon atoms).

[0092] In the above formula (V), R 3 Examples of the halogen-substituted or unsubstituted monovalent hydrocarbon group of X include the above-mentioned alkenyl group, epoxy group-containing organic group, and other monovalent hydrocarbon groups. The alkyl group of 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.

[0093] In the above formula (V), f is preferably in the range of 0.1≦f≦0.9, more preferably in the range of 0.3≦f≦0.8, and even more preferably in the range of 0.5≦f≦0.7. In the above formula (V), g is preferably in the range of 0.05≦g≦0.6, more preferably in the range of 0.1≦g≦0.5, and particularly in the range of 0.15≦g≦0.4. In the above formula (V), h is preferably in the range of 0≦h≦0.5, more preferably in the range of 0≦h≦0.3, and particularly in the range of 0≦h≦0.1. In the above formula (V), i is preferably in the range of 0≦i≦0.2, more preferably in the range of 0≦i≦0.1, and particularly in the range of 0≦i≦0.05.

[0094] In one embodiment of the present invention, the resin-like epoxy group-containing organosiloxane oligomer is SiO 1 / 2 In another embodiment of the present invention, in the above formula (V), g is greater than 0, that is, the resin-like epoxy group-containing organosiloxane oligomer does not contain a siloxane unit (M unit) represented by SiO 3 / 2 The resin-like epoxy group-containing organosiloxane oligomer contains a siloxane unit (T unit) represented by SiO 4 / 2The resin-like epoxy-containing organosiloxane oligomer may or may not contain a siloxane unit (Q unit) represented by the formula (V), but preferably does not contain one. In another embodiment of the present invention, in the above formula (V), i is greater than 0, that is, the resin-like epoxy-containing organosiloxane oligomer has at least one -OX group bonded to a silicon atom. In one embodiment of the present invention, the resin-like epoxy-containing organosiloxane oligomer is composed of only D units and T units.

[0095] In another embodiment of the present invention, the epoxy group-containing organosiloxane oligomer is a condensation reaction product of at least one organosilane compound that contains at least one epoxy group.The condensation reaction product may be derived from one type of organosilane compound, or may be derived from two or more types of organosilane compounds.In other words, the epoxy group-containing organosiloxane oligomer contains a unit derived from the organosilane compound that contains at least one epoxy group in its structure.

[0096] The condensation reaction may be a hydrolysis-condensation reaction, and therefore the epoxy group-containing organosiloxane oligomer may be a hydrolysis-condensation reaction product.

[0097] The degree of condensation in the condensation reaction is not particularly limited, but may be 2 to 20, preferably 3 to 15, and more preferably 3 to 10 siloxane units.

[0098] The organosilane compound containing at least one epoxy group may be a monosilane compound. The epoxy group contained in such an organosilane compound may be the same as the epoxy group described above.

[0099] In one embodiment of the present invention, the organosilane compound has the formula: (4-b) Six b (wherein, R is the same or different organic functional group having at least one epoxy group; X is the same or different, and represents an alkoxy group, such as a methoxy group, an ethoxy group, and a propoxy group; an oxime group, such as an acetoxime group, a methylethylketoxime group; an amino group, such as a dimethylamino group, a diethylamino group; an amide group, such as an N-methylacetamide group; an aminooxy group, such as a diethylaminooxy group; an alkenyloxy group, such as an isopropenyloxy group; and b is 1, 2, or 3, preferably 2 or 3, and more preferably 3.) It can be expressed as:

[0100] In the formula representing the organosilane compound, X is preferably an alkoxy group, preferably C 1 ~C 6 Alkoxy groups are selected from, for example, methoxy, ethoxy, and propoxy groups.

[0101] The organosilane compound may be a silane coupling agent. Examples of such organosilane compounds include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, glycidyloxypropyl(dimethoxy)methylsilane, glycidyloxypropyl(trimethoxy)silane, and 2-(3,4-epoxy)cyclohexyl)ethyltrimethoxysilane.

[0102] In a particular embodiment of the present invention, the epoxy group-containing organosiloxane oligomer is a condensation reaction product of 2-20 glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, glycidyloxypropyl(dimethoxy)methylsilane, glycidyloxypropyl(trimethoxy)silane, 2-(3,4-epoxy)cyclohexyl)ethyltrimethoxysilane, glycidyloxypropyl(trimethoxy)silane, and any combination thereof, in particular a condensation reaction product of four glycidyloxypropyl(trimethoxy)silanes.

[0103] In yet another embodiment of the present invention, the epoxy group-containing organosiloxane oligomer is a condensation reaction product of at least one organosilane compound containing at least one epoxy group and at least one organosilane compound or its oligomer containing at least one organic functional group other than epoxy group.In one embodiment, the epoxy group-containing organosiloxane oligomer is a condensation reaction product of at least one organosilane compound containing at least one epoxy group and at least one organosilane compound or its oligomer containing at least one ethylenically unsaturated group such as alkenyl group, for example vinyl group.

[0104] In yet another embodiment of the present invention, the epoxy group-containing organosiloxane oligomer is a condensation reaction product of an organosiloxane oligomer having vinyl groups, both molecular terminals of which are capped with silanol groups, and 3-glycidoxypropyltrimethoxysilane.

[0105] The amount of epoxy-containing organic groups in the total silicon-bonded organic groups in the epoxy-containing organosiloxane oligomer is not particularly limited, but is, for example, 3 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, and usually 50 mol% or less, preferably 40 mol% or less, more preferably 30 mol% or less.The amount of epoxy-containing organic groups can be determined, for example, by analysis using a Fourier transform infrared spectrophotometer (FT-IR), nuclear magnetic resonance (NMR), etc.

[0106] The mass average molecular weight (Mw) of the epoxy group-containing organosiloxane oligomer is not particularly limited, but may be within the range of 500 to 3,000, and preferably 800 to 2,000. In this specification, the mass average molecular weight can be measured by GPC.

[0107] The content of the epoxy group-containing organopolysiloxane is not particularly limited, but is preferably 0.01 mass % or more, more preferably 0.1 mass % or more, and even more preferably 0.3 mass % or more, based on the total mass of the curable silicone composition of the present invention, and may be 10 mass % or less, more preferably 5 mass % or less, and even more preferably 3 mass % or less, based on the total mass of the curable silicone composition of the present invention.

[0108] The cerium-containing organopolysiloxane can be prepared, for example, by reacting cerium chloride or a cerium salt of a carboxylic acid with an alkali metal salt of a silanol group-containing organopolysiloxane. Therefore, in this specification, the term "cerium-containing organopolysiloxane" can mean a compound obtained by reacting a silanol group-containing organopolysiloxane with a cerium salt, in which the silanol group of the organopolysiloxane is chemically bonded to a cerium atom.

[0109] Examples of the cerium salts of the above carboxylic acids include cerium 2-ethylhexanoate, cerium naphthenate, cerium oleate, cerium laurate, and cerium stearate. Examples of the cerium chloride include cerium trichloride.

[0110] Examples of the alkali metal salt of the silanol group-containing organopolysiloxane include potassium salts of diorganopolysiloxanes having both molecular chain ends blocked with silanol groups, sodium salts of diorganopolysiloxanes having both molecular chain ends blocked with silanol groups, potassium salts of diorganopolysiloxanes having one molecular chain end blocked with a silanol group and the other molecular chain end blocked with a triorganosiloxy group, and sodium salts of diorganopolysiloxanes having one molecular chain end blocked with a silanol group and the other molecular chain end blocked with a triorganosiloxy group. Examples of groups bonded to silicon atoms in this organopolysiloxane include alkyl groups having 1 to 12 carbon atoms, such as methyl groups, ethyl groups, propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, tert-butyl groups, n-pentyl groups, neopentyl groups, hexyl groups, cyclohexyl groups, heptyl groups, octyl groups, nonyl groups, decyl groups, undecyl groups, and dodecyl groups; aryl groups having 6 to 20 carbon atoms, such as phenyl groups, tolyl groups, xylyl groups, and naphthyl groups; aralkyl groups having 7 to 20 carbon atoms, such as benzyl groups, phenethyl groups, and phenylpropyl 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, and bromine atoms.

[0111] The above reaction is carried out at room temperature or by heating in an organic solvent such as alcohols such as methanol, ethanol, isopropanol, and butanol; aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as hexane and heptane; mineral split, ligroin, and petroleum ether. It is also preferable to distill off the organic solvent or low boiling point components from the resulting reaction product, or to filter the precipitate, as necessary. In order to promote this reaction, dialkylformamide, hexaalkylphosphoamide, and the like may be added. The content of cerium atoms in the cerium-containing organopolysiloxane thus prepared is preferably within the range of 0.1 to 15% by mass.

[0112] The content of the cerium-containing organopolysiloxane is not particularly limited, but is preferably 0.1 mass% or more, more preferably 0.3 mass% or more, based on the total mass of the curable silicone composition of the present invention. The cerium-containing organopolysiloxane is usually contained in an amount of 5 mass% or less, preferably 3 mass% or less, based on the total mass of the curable silicone composition.

[0113] (Other ingredients) The curable silicone composition of the present invention can be blended with optional components within a range that does not impair the object of the present invention. Examples of the optional components include acetylene compounds, organic phosphorus compounds, vinyl group-containing siloxane compounds, inorganic fillers, such as inorganic fillers such as crushed quartz, silica, magnesium carbonate, diatomaceous earth, inorganic fillers obtained by hydrophobizing the surface of such inorganic fillers with organic silicon compounds, surface treatment agents, hydrosilylation reaction inhibitors, tackifiers, heat resistance agents, cold resistance agents, flame retardants, thixotropy agents, phosphors, solvents, etc. The amount of such optional components added is usually 0.001 to 20 mass% of the entire composition.

[0114] Hydrosilylation reaction inhibitor is a component for suppressing the hydrosilylation reaction of curable silicone composition.As such curing reaction inhibitor, for example, 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 2-phenyl-3-butyn-2-ol, 1-ethynyl-1-cyclohexanol, 1-ethynyl-2-cyclohexanol and other alkyne alcohols; 3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexen-1-yne and other enyne compounds; tetramethyltetravinylcyclotetrasiloxane, tetramethyltetrahexenylcyclotetrasiloxane and other alkenyl group-containing low molecular weight siloxanes; methyl-tris(1,1-dimethylpropynyloxy)silane, vinyl-tris(1,1-dimethylpropynyloxy)silane, methyl-tris(3-methyl-1-butyn-3-oxy)silane and other alkynyloxysilanes. The hydrosilylation reaction inhibitor is preferably selected from the group consisting of alkyne alcohols, and particularly preferably 1-ethynyl-1-cyclohexanol. The amount of the reaction inhibitor added is usually 0.001 to 5% by mass of the entire composition.

[0115] The curable silicone composition according to the present invention can be cured to form a cured product having good transparency. Specifically, the cured product of the curable silicone composition according to the present invention is less likely to yellow even after heating and can maintain high transparency. For example, a 2 mm-thick cured product of the curable silicone composition according to the present invention preferably has a light transmittance of 95% or more at wavelengths of 400 nm to 700 nm even after being maintained at 150° C. for 48 hours. The light transmittance of the cured product of the curable silicone composition can be determined, for example, by measuring the cured product with a spectrophotometer.

[0116] The curable silicone composition of the present invention exhibits practically effective curability even at low temperatures, exhibits little change in shape or shrinkage during curing, and can be cured in a short time to form a cured product. For example, the curable silicone composition of the present invention can be cured by heating at a temperature of 50 to 150°C, preferably 60 to 120°C, and more preferably 70°C to 100°C for 30 seconds or more, preferably 45 seconds or more.

[0117] The curable silicone composition of the present invention can be prepared by mixing each component. The method of mixing each component can be a conventionally known method and is not particularly limited, but for example, it can be prepared by mixing using a mixing device. There is no particular limit to such a mixing device, and examples of such a mixing device include a single-screw or double-screw continuous mixer, a double roll, a Ross mixer, a Hobart mixer, a dental mixer, a planetary mixer, a kneader mixer, and a Henschel mixer.

[0118] [Sealant] The present invention also relates to an encapsulant for semiconductors that contains the curable silicone composition of the present invention.The present invention also relates to an encapsulant obtained by curing the encapsulant of the present invention.That is, the encapsulant of the present invention may contain a cured product of the curable silicone composition of the present invention.

[0119] The shape of the encapsulant of the present invention is not particularly limited, but is preferably a dome shape or a sheet shape. The semiconductor to be encapsulated by the encapsulant, encapsulant or film of the present invention is not particularly limited, and examples thereof include semiconductors such as SiC and GaN, particularly power semiconductors and optical semiconductors such as light-emitting diodes.

[0120] [Optical semiconductor element] The present invention also relates to an optical semiconductor element encapsulated with the cured product of the encapsulant of the present invention. That is, the optical semiconductor element of the present invention comprises the cured product of the encapsulant of the present invention. Examples of the optical semiconductor element include a light-emitting diode (LED), a semiconductor laser, a photodiode, a phototransistor, a solid-state image sensor, and a light emitter and a light receiver for a photocoupler, and a light-emitting diode (LED) is particularly preferable.

[0121] Since light emitting diodes (LEDs) emit light from the top, bottom, left and right of the optical semiconductor element, it is preferable that the components constituting the light emitting diode (LED) are not light absorbing, and are preferably made of materials with high light transmittance or high reflectance. Therefore, it is preferable that the substrate on which the optical semiconductor element is mounted is also made of materials with high light transmittance or high reflectance. Examples of substrates on which such optical semiconductor elements are mounted include conductive metals such as silver, gold, and copper; non-conductive metals such as aluminum and nickel; thermoplastic resins mixed with white pigments such as PPA and LCP; thermosetting resins containing white pigments such as epoxy resins, BT resins, polyimide resins, and silicone resins; and ceramics such as alumina and alumina nitride.

[0122] Specific embodiments of the present invention will be described below. Aspect 1: (A) an MQ resinous alkenyl-containing organopolysiloxane having at least two alkenyl groups per molecule; (B) a resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; (C) a linear organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; (D) Curing catalyst A curable silicone composition comprising: (B) the content of the resinous organohydrogenpolysiloxane is 5% by mass or more based on the total mass of the composition; the total content of the resinous organohydrogenpolysiloxane (B) and the linear organohydrogenpolysiloxane (C) is 13 mass% or more based on the total mass of the composition; A curable silicone composition, in which the mass ratio of the content of the resinous organohydrogenpolysiloxane (B) to the content of the linear organohydrogenpolysiloxane (C) is 0.8 or greater. Aspect 2: The curable silicone composition according to Aspect 1, wherein the content of (A) the MQ resinous alkenyl group-containing organopolysiloxane is from 30% to 80% by mass. Aspect 3: The curable silicone composition according to Aspect 1 or 2, wherein (B) the resinous organohydrogenpolysiloxane has a network-like molecular structure. Aspect 4: The curable silicone composition according to any one of Aspects 1 to 3, wherein the (B) resinous organohydrogenpolysiloxane comprises an MQ resinous organohydrogenpolysiloxane and / or a resinous organohydrogenpolysiloxane composed only of M units and T units. Aspect 5: The curable silicone composition according to any one of Aspects 1 to 4, wherein the mass ratio of the content of the resinous organohydrogenpolysiloxane (B) to the content of the linear organohydrogenpolysiloxane (C) is 3 or less. Aspect 6: A semiconductor encapsulant comprising the curable silicone composition according to any one of Aspects 1 to 5. Embodiment 7: An optical semiconductor device comprising the adhesive according to embodiment 6. EXAMPLES

[0123] The curable silicone composition of the present invention will be described in more detail below with reference to the following examples and comparative examples.

[0124] The components were mixed in the composition (parts by mass) shown in the table to prepare a curable silicone composition. In the following, Me represents a methyl group, Vi represents a vinyl group, and Ep represents a 3-glycidoxypropyl group. In addition, the structures of the organopolysiloxane components are 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. Furthermore, H / Vi represents the molar ratio of silicon-bonded hydrogen atoms (H) to vinyl groups (Vi) in the organopolysiloxane component. In the present specification, (SiO x / 2 ) (where x is an integer from 1 to 4) is shown as a "unit formula", and a "structural formula" is a chemical formula that does not include such a siloxane unit. In the table, "nd" indicates that no measurement was performed.

[0125] Component a-1: Average unit formula (Me 3 SiO 1 / 2 )42 (ViMe 2 SiO 1 / 2 ) 7 (SiO 4 / 2 ) 51 (OH) 4 The MQ resin-like alkenyl-containing organopolysiloxane (solid at 25°C, number of siloxane units = 55, number average molecular weight (Mn) = 3900, weight average molecular weight (Mw) = 5400) Component a-2: Average structural formula ViMe 2 SiO(M 2 SiO) 40 Sim 2 Linear alkenyl-containing organopolysiloxane represented by Vi Component a-3: Average structural formula ViMe 2 SiO(M 2 SiO) 150 Sim 2 Linear alkenyl-containing organopolysiloxane represented by Vi Component a-4: Average unit formula (Me 3 SiO 1 / 2 ) 39 (ViMe 2 SiO 1 / 2 ) 6 (SiO 4 / 2 ) 55 MQ resin-like alkenyl-containing organopolysiloxane (solid at 25°C) represented by the formula: Component b-1: Average unit formula (Me 2 HSiO 1 / 2 ) 62 (SiO 4 / 2 ) 38 MQ resin-type organohydrogenpolysiloxane (number average molecular weight (Mn) = 1300, weight average molecular weight (Mw) = 1700, has a mesh-like molecular structure) Component b-2: Average unit formula (Me 2 HSiO 1 / 2 ) 60 (PhSiO 3 / 2 ) 40 Resin-like organohydrogenpolysiloxane (number average molecular weight (Mn) = 700, weight average molecular weight (Mw) = 750, has a mesh-like molecular structure) Component c-1: Average structural formula Me 2 HSiO(Me 2 SiO) 20 SiHMe 2 A linear organohydrogenpolysiloxane represented by the formula: Component c-2: Average structural formula Me 2 HSiO(Ph 2 SiO)SiHMe 2 A linear organohydrogenpolysiloxane represented by the formula: Component d: A complex of platinum and divinyltetramethyldisiloxane having a platinum concentration of 3.0 mass% Component e: Average unit formula (EpSiO 3 / 2 ) a (MeViSiO 2 / 2 ) b (Me 2 SiO 2 / 2 ) c (OX) d A condensation reaction product of an organosiloxane oligomer having vinyl groups, both ends of which are capped with silanol groups, and 3-glycidoxypropyltrimethoxysilane (mass average molecular weight: 1280). Component f: cerium-containing dimethylpolysiloxane having a cerium content of 1.4% by mass Component g: 1-ethynyl-1-cyclohexanol

[0126] The following evaluations were carried out:

[0127] [Curability] The resulting curable silicone composition was used in a curability tester (a moving die rheometer (MDR)) to measure the time taken from immediately after measurement at a temperature of 90° C. until the torque reached saturation.

[0128] [Light transmittance of cured product] 3 g of the obtained curable silicone composition was heated in a mold (10 mm x 50 mm x 2 mm) at 90°C for 5 minutes to produce a cured product with a thickness of 2 mm. This cured product was aged at 150°C for 48 hours, and then its light transmittance (wavelength 450 nm) was measured at 25°C. A transmittance of 95% or more was rated as OK.

[0129] [Cure shrinkage] 15 g of the obtained curable silicone composition was pressed into a mold (10 cm x 15 cm x 1 mm) at 90°C for 5 minutes to produce a cured product. After cooling this cured product to room temperature, its dimensions were measured, and the rate of change in dimensions was taken as the cure shrinkage rate. Products with cure shrinkage of 1.0% or less were rated as OK. This cure shrinkage corresponds to the volumetric shrinkage during curing of the composition.

[0130] [Die shear strength] A 25 mm x 75 mm aluminum plate was used as a substrate, and a circular space of 8 mm diameter x 200 um thickness was left, filled with a silicone composition, and an aluminum chip was placed thereon, and then cured at 90°C for 5 minutes to bond each chip to the substrate. The uncured composition was cured at 90°C until it was cured. The die shear strength was measured using a bond tester (model number: SS-30WD, test mode: PH50 push, speed: 0.120 mm / sec).

[0131] [Table 1]

[0132] [Table 2]

[0133] As can be seen from the results in Table 1, the curable silicone composition of the present invention can be cured within 5 minutes even at a low temperature of 90°C, has little cure shrinkage, maintains high transparency even after aging at high temperature, and can form a cured product with excellent adhesive strength. Also, as can be seen from the results in Table 2, Comparative Examples 1 to 5 and 7, which are outside the scope of the present invention, required more than 5 minutes to cure by heat treatment at 90°C. Also, the adhesive strength of the cured product of Comparative Example 7 was insufficient. [Industrial Applicability]

[0134] The curable silicone composition of the present invention can be used as an encapsulant or covering material for optical semiconductor elements such as light-emitting diodes (LEDs).

Claims

1. (A) an MQ resinous alkenyl-containing organopolysiloxane having at least two alkenyl groups per molecule; (B) a resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; (C) a linear organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; (D) Curing catalyst A curable silicone composition comprising: (B) the content of the resinous organohydrogenpolysiloxane is 5% by mass or more based on the total mass of the composition; the total content of the resinous organohydrogenpolysiloxane (B) and the linear organohydrogenpolysiloxane (C) is 13 mass% or more based on the total mass of the composition; the mass ratio of the content of the resinous organohydrogenpolysiloxane (B) to the content of the linear organohydrogenpolysiloxane (C) is 0.8 or more; A curable silicone composition.

2. 2. The curable silicone composition according to claim 1, wherein the content of (A) the MQ resinous alkenyl-group-containing organopolysiloxane is from 30% to 80% by weight.

3. 3. The curable silicone composition according to claim 1, wherein the resinous organohydrogenpolysiloxane (B) has a network-like molecular structure.

4. 2. The curable silicone composition according to claim 1, wherein the resinous organohydrogenpolysiloxane (B) comprises an MQ resinous organohydrogenpolysiloxane and / or a resinous organohydrogenpolysiloxane composed only of M units and T units.

5. 2. The curable silicone composition according to claim 1, wherein the mass ratio of the content of the resinous organohydrogenpolysiloxane (B) to the content of the linear organohydrogenpolysiloxane (C) is 3 or less.

6. A semiconductor encapsulant comprising the curable silicone composition according to any one of claims 1 to 5.

7. An optical semiconductor device comprising the encapsulant according to claim 6 .

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