Curable silicone composition

Abstract

To provide a curable silicone composition which can be rapidly cured at low temperatures and is capable of forming a cured product having less volume shrinkage when cured and better transparency and adhesive strength after heating. [Solution] This problem is solved by means of a curable silicone composition comprising: (A) an MQ resinous alkenyl group-containing organopolysiloxane having at least two alkenyl groups per molecule; (B) a resinous organohydrogenpolysiloxane 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, in which the content of the (B) resinous organohydrogenpolysiloxane is 5 mass% or more with respect to the total mass of the composition, the total content of the (B) resinous organohydrogenpolysiloxane and the (C) linear organohydrogenpolysiloxane is 13 mass% or more with respect to the total mass of the composition, and the mass ratio of the content of the (B) resinous organohydrogenpolysiloxane to the content of the (C) linear organohydrogenpolysiloxane is 0.8 or more.

Description

Technical Field

[0001] The present invention relates to a curable silicone composition, and more particularly to a curable silicone composition suitable for an encapsulation material for an optical semiconductor. Background Art

[0002] When curable silicone compositions are cured, they form cured products having excellent heat resistance, cold resistance, electrical insulation properties, weather resistance, water repellency and transparency, and therefore they are used in a wide range of industrial fields. In particular, compared with other organic materials, these cured products are less likely to change color, and their physical properties such as durability deteriorate less, and therefore they are used for optical materials, and in particular are widely used as silicone encapsulation materials used in optical semiconductor devices such as light emitting diodes (LEDs).

[0003] For example, Japanese Unexamined Patent Publication No. 2010-174233 (Patent Document 1) discloses a curable silicone composition comprising: alkenyl-containing dialkyl polysiloxane; resinous alkenyl-containing organopolysiloxane; organopolysiloxane having silicon-bonded hydrogen atoms and having SiO4 / 2 units; linear organopolysiloxane having silicon-bonded hydrogen atoms; and a hydrosilylation catalyst. In the example of Patent Document 1, the curable silicone rubber composition is press-cured at 120° C. for 10 minutes and further treated at 200° C. for 4 hours.

[0004] Patent document 2 also discloses a curable silicone resin composition for use as a die attach material for optical semiconductors, wherein the composition comprises 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 silicon-bonded hydrogen atoms, a linear organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms, and a catalyst.

[0005] Patent document 3 also discloses an addition-curable silicone resin composition for use as a die attach material for optical semiconductors, wherein the composition comprises 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 silicon-bonded hydrogen atoms, and an addition reaction catalyst.

[0006] Patent Document 4 also discloses a silicone resin composition for molding a lens, the composition comprising an organopolysiloxane having two or more aliphatic unsaturated bonds per molecule, a branched organohydrogenpolysiloxane having three or more silicon-atom-bonded hydrogen atoms per molecule, and a platinum group metal-based catalyst. In the example of Patent Document 4, the silicone resin composition for molding a lens is molded at 150° C. for 90 seconds.

[0007] Patent Document 5 also discloses encapsulating an optical semiconductor with a cured product of a curable silicone composition, the curable silicone composition consisting of at least: a linear organopolysiloxane having at least two silicon-bonded alkenyl groups per molecule, wherein at least 5 mol% of all silicon-bonded organic groups are aromatic groups; 1 3SiO 1 / 2 (In the formula, R 1 are the same or different monovalent hydrocarbon groups) and the siloxane units represented by the formula SiO 4 / 2 An organopolysiloxane composed of siloxane units represented by , wherein the content of alkenyl groups is at least 6% by weight; an organopolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; and a hydrosilylation catalyst. Comparative Example 5 of Patent Document 5 discloses a composition comprising, based on the total weight of polysiloxanes capable of participating in a hydrosilylation reaction: 88% by weight of a linear organopolysiloxane having at least two alkenyl groups but no aryl group as any of the 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 (capped with silanol groups at both ends of the molecular chain) and 3-glycidoxypropyltrimethoxysilane.

[0008] Patent document 6 also discloses coating a light-emitting element with a cured product of an addition-curable silicone composition, the composition comprising an organic polysiloxane having a network structure and having at least two alkenyl groups per molecule, a straight-chain organic polysiloxane having at least two alkenyl groups per molecule, a branched organic hydrogen polysiloxane having at least two hydrosilyl groups per molecule, a straight-chain organic hydrogen polysiloxane having at least two hydrosilyl groups per molecule, and a hydrosilylation catalyst.

[0009] Patent Document 7 discloses encapsulating an optical semiconductor with a curable organopolysiloxane composition comprising an organopolysiloxane having an alkenyl group and an aryl group, an organohydrogenpolysiloxane, and an addition reaction catalyst.

[0010] Patent document 8 also discloses a thermally conductive silicone composition comprising a linear organopolysiloxane having at least two alkenyl groups per molecule, an organohydrogenpolysiloxane consisting only of M units, D units, and T units, and a linear organohydrogenpolysiloxane. Comparative Example 3 of Japanese Unexamined Patent Publication No. H10-231428 (Patent document 9) discloses a composition comprising 100 parts by weight of a dimethylpolysiloxane terminated with vinyldimethylsilyl groups at both ends of the molecular chain 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 cured via a hydrosilylation reaction, the composition must sometimes be cured at high temperatures for a long time. For example, the examples in the above-mentioned patent documents 2, 3, 5, 6 and 7 disclose that the curable silicone composition is cured by heating at 150°C for at least 1 hour. This long curing time leads to lower productivity. When the curable silicone composition must be heated at high temperatures for a long period of time, the electronic device such as an optical semiconductor element to which the curable silicone composition is applied may also be damaged by heating. Therefore, a curable silicone composition that can be cured quickly at low temperatures is required. Using a larger amount of hydrosilylation catalyst is considered to be a method that will allow the curable silicone composition to be cured quickly at low temperatures. However, using a larger amount of hydrosilylation catalyst in a curable silicone composition may sometimes cause the cured product to be significantly discolored, which cannot be used in applications such as optical semiconductor device packaging, where the cured product must be transparent.

[0012] Curable silicone compositions cured via hydrosilylation reactions may sometimes experience high volume shrinkage when cured. Such volume shrinkage may cause the flexible film to curl and reduce the accuracy of controlling flatness and thickness. Low viscosity in curable silicone compositions is also important for improving processing efficiency in processes where, for example, optical semiconductor devices are encapsulated by curable silicone compositions. Low viscosity in curable silicone compositions is also important for self-leveling properties required in, for example, screen printing processes.

[0013] [Prior art literature]

[0014] [Patent Document]

[0015] [Patent Document 1] Japanese Unexamined Patent Publication No. 2010-174233

[0016] [Patent Document 2] Japanese Unexamined Patent Publication No. 2018-131583

[0017] [Patent Document 3] Japanese Unexamined Patent Publication No. 2016-155967

[0018] [Patent Document 4] Japanese Unexamined Patent Publication No. 2006-328102

[0019] [Patent Document 5] International Patent Publication No. 2018 / 062009

[0020] [Patent Document 6] Japanese Unexamined Patent Publication No. 2016-204423

[0021] [Patent Document 7] Japanese Unexamined Patent Publication No. 2015-218233

[0022] [Patent Document 8] Japanese Unexamined Patent Publication No. 2009-292928 Summary of the invention

[0023] [Problems to be Solved by the Invention]

[0024] An object of the present invention is to provide a curable silicone composition which can be rapidly cured at low temperatures and can form a cured product which has a small volume shrinkage during curing and has good transparency and good adhesive strength after heating.

[0025] [Methods of solving the problem]

[0026] As a result of extensive studies conducted to solve the above-mentioned problems, the inventors completed the present invention after unexpectedly finding that the combination of an MQ resinous alkenyl-containing organopolysiloxane and a specific organohydrogenpolysiloxane allows the formation of a cured product having less volume shrinkage upon curing and better adhesive strength by means of a rapid curing reaction at low temperatures.

[0027] Therefore, the present invention relates to

[0028] A curable silicone composition comprising:

[0029] (A) an MQ resinous alkenyl-containing organopolysiloxane having at least two alkenyl groups per molecule;

[0030] (B) a resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule;

[0031] (C) a linear organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; and

[0032] (D) a curing catalyst,

[0033] in

[0034] (B) the content of the resinous organohydrogenpolysiloxane is 5% by mass or more relative to the total mass of the composition,

[0035] The total content of (B) the resinous organohydrogenpolysiloxane and (C) the linear organohydrogenpolysiloxane is 13% by mass or more relative to the total mass of the composition, and

[0036] The mass ratio of the content of the (B) resinous organohydrogenpolysiloxane to the content of the (C) linear organohydrogenpolysiloxane is 0.8 or more.

[0037] The content of the (A)MQ resinous alkenyl group-containing organopolysiloxane is preferably 30% by mass to 80% by mass.

[0038] The (B) resinous organohydrogenpolysiloxane preferably has a network molecular structure.

[0039] (B) The resinous organohydrogenpolysiloxane preferably includes an MQ resinous organohydrogenpolysiloxane and / or a resinous organohydrogenpolysiloxane consisting only of M units and T units.

[0040] The mass ratio of the content of the (B) resinous organohydrogenpolysiloxane relative to the content of the (C) linear organohydrogenpolysiloxane is preferably 3 or less.

[0041] The present invention also relates to an encapsulation material for a semiconductor device, the encapsulation material being formed from the curable silicone composition of the present invention.

[0042] The present invention also relates to an optical semiconductor device comprising the encapsulation material for a semiconductor according to the present invention.

[0043] [Effects of the invention]

[0044] The curable silicone composition according to the present invention can be rapidly cured at low temperature to form a cured product having less volume shrinkage during curing and better transparency and better adhesive strength after heating. DETAILED DESCRIPTION

[0045] [Curable silicone composition]

[0046] The curable silicone composition according to the present invention comprises at least:

[0047] A curable silicone composition comprising:

[0048] (A) an MQ resinous alkenyl-containing organopolysiloxane having at least two alkenyl groups per molecule;

[0049] (B) a resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule;

[0050] (C) a linear organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; and

[0051] (D) a curing catalyst,

[0052] And among them,

[0053] (B) the content of the resinous organohydrogenpolysiloxane is 5% by mass or more relative to the total mass of the composition,

[0054] The total content of (B) the resinous organohydrogenpolysiloxane and (C) the linear organohydrogenpolysiloxane is 13% by mass or more relative to the total mass of the composition, and

[0055] The mass ratio of the content of the (B) resinous organohydrogenpolysiloxane to the content of the (C) linear organohydrogenpolysiloxane is 0.8 or more.

[0056] The components of the curable silicone composition of the present invention are described in detail below.

[0057] (A) MQ resinous alkenyl-containing organopolysiloxane having at least two alkenyl groups per molecule

[0058] Component (A) is an organopolysiloxane having at least two alkenyl groups per molecule. The curable silicone composition according to the present invention may contain one type of (A)MQ resinous alkenyl-containing organopolysiloxane, or may contain two or more types of (A)MQ resinous alkenyl-containing organopolysiloxane.

[0059] The molecular structure of component (A) is in the form of MQ resin. As used in this specification, resinous means branched or network configuration, and preferably network configuration. MQ resin means only R3SiO 1 / 2 The siloxane unit (M unit) and SiO 4 / 2 The resinous organopolysiloxane is composed of siloxane units (Q units) represented by . R in the siloxane unit means an organic group bonded to a silicon atom.

[0060] Examples of the alkenyl group in component (A) include C2-12 alkenyl groups such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl, and preferably vinyl.

[0061] Examples of silicon-bonded groups (except alkenyl) in component (A) include halogen-substituted or unsubstituted monovalent hydrocarbon groups (except alkenyl), such as: C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl; C7-20 aralkyl groups, such as benzyl, phenethyl, and phenylpropyl; and any of these groups in which some or all of the hydrogen atoms are replaced by halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms. The silicon atom in component (A) may contain a small amount of hydroxyl or alkoxy groups such as methoxy or ethoxy, provided that the purpose of the present invention is not impaired thereby. The silicon-bonded groups (except alkenyl) in component (A) are preferably selected from C1-6 alkyl groups, and particularly methyl groups.

[0062] The MQ resinous alkenyl-containing organopolysiloxane of component (A) may preferably be represented by the following average unit formula (I):

[0063] Average unit formula (I): (R 1 3SiO 1 / 2 ) s(SiO 4 / 2 ) t (XO 1 / 2 ) u

[0064] In the formula, R 1 denotes a halogen-substituted or unsubstituted monovalent hydrocarbon group, which may be the same or different, provided that at least two R per molecule 1 are alkenyl; 0 < s < 1, 0 < t < 1, 0 ≤ u < 0.4, and s + t = 1.0; and u is the number of (XO) groups per silicon atom (the ratio of the number of (XO) groups per silicon atom).

[0065] In the above formula (I), examples of the halogen-substituted or unsubstituted monovalent hydrocarbon group represented by R 1 include: C1-12 alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C6-20 aryl groups such as phenyl, tolyl, xylyl, and naphthyl; C7-20 aralkyl groups such as benzyl, phenethyl, and phenylpropyl; C2-12 alkenyl groups such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl; and any of these groups in which some or all of the hydrogen atoms are replaced by halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms. R 1 may also be a small amount of hydroxyl or alkoxy groups such as methoxy or ethoxy, provided that the object of the present invention is not impaired thereby. R 1 is preferably selected from C1-6 alkyl groups, and particularly methyl, or C2-6 alkenyl groups, and particularly vinyl.

[0066] In the above formula (I), X is a hydrogen atom or an alkyl group. Preferred examples of the alkyl group represented by X include C1-3 alkyl groups, specifically methyl, ethyl, and propyl. X is preferably a hydrogen atom.

[0067] 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 the above 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 the above 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.

[0068] The content of alkenyl in all silicon-bonded organic groups of the MQ resinous alkenyl-containing organopolysiloxane of component (A) is not particularly limited, but can be, for example, 1 mol% or more, preferably 2 mol% or more, and more preferably 3 mol% or more of the total number of silicon-bonded organic groups, and can be 20 mol% or less, preferably 15 mol%, and more preferably 10 mol% or less of the total number of silicon-bonded organic groups. The content of alkenyl can be determined by means of analysis such as Fourier transform infrared spectrophotometry (FT-IR) or nuclear magnetic resonance (NMR), or by means of titration described below. As used in this specification, numerical ranges can be established (if appropriate) by combining any upper and lower limits of the numerical range.

[0069] A method for determining the amount of alkenyl groups in a component by means of titration will be described. The alkenyl content in an organopolysiloxane component can be accurately quantified by means of a titration method commonly referred to as the Wijs method. The principle is described as follows. First, the alkenyl groups in the organopolysiloxane starting material and iodine monochloride are subjected to an addition reaction as shown in formula (1). Next, according to the reaction shown in formula (2), excess iodine monochloride is reacted with potassium iodide to release iodine. The released iodine is titrated with a sodium thiosulfate solution.

[0070] Formula (1): CH2=CH-+2ICl→CH2I-CHCl-+ICl(excess)

[0071] Formula (2): ICl + KI → I2 + KCl

[0072] The amount of olefinic groups in a component can be quantified by the difference between the amount of sodium thiosulfate required for titration and the titration of a separately prepared blank solution.

[0073] The content of aryl groups in all silicon-bonded organic groups of the MQ resinous alkenyl-containing organopolysiloxane of component (A) is not particularly limited, but may be, for example, 20 mol% or less, preferably 10 mol%, and more preferably 5 mol% or less of the total number of silicon-bonded organic groups. In one embodiment of the present invention, the MQ resinous alkenyl-containing organopolysiloxane of component (A) does not contain aryl groups as silicon-bonded organic groups.

[0074] The aryl content can be determined, for example, by analysis such as Fourier transform infrared spectroscopy (FT-IR) or nuclear magnetic resonance (NMR).

[0075] (A)MQ resinous alkenyl-containing organopolysiloxane has no particular limitation on viscosity. For example, component (A) is preferably solid at 25°C. For example, the viscosity at 25°C is in the range of 1 mPa·s to 200,000 mPa·s, and more preferably in the range of 5 mPa·s to 100,000 mPa·s. As used in this specification, the viscosity of the organopolysiloxane component can be determined using a rotational viscometer according to JIS K 7117-1.

[0076] The number average molecular weight of the (A)MQ resinous alkenyl-containing organopolysiloxane may be, for example, but not particularly limited to, 1,000 or more, and preferably 1,500 or more, and may be 200,000 or less, more preferably 150,000 or less, and even more preferably 100,000 or less. As used in this specification, the number average molecular weight (Mn) and the weight average molecular weight (Mw) are values ​​calculated based on standard polystyrene, as determined by gel permeation chromatography (GPC).

[0077] (A) MQ resinous siloxane units (SiO x / 2 ) may be, for example, but not particularly limited to, 5 to 2,000, and preferably 10 to 1,000.

[0078] The content of the (A)MQ resinous alkenyl-containing organopolysiloxane is typically, but not particularly limited to, 30% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more, based on the total mass of the curable silicone composition of the present invention. The content of component (A) is also typically 80% by mass or less, preferably 70% by mass or less, and more preferably 60% by mass or less, based on the total mass of the curable silicone composition of the present invention.

[0079] (B) a resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule

[0080] Component (B) is a resinous organohydrogenpolysiloxane that acts as a crosslinker for the curable silicone composition through a hydrosilylation curing reaction and has at least two silicon-bonded hydrogen atoms per molecule. The curable silicone composition according to the present invention may contain one type of (B) resinous organohydrogenpolysiloxane, or may contain two or more types of (B) resinous organohydrogenpolysiloxanes.

[0081] Examples of silicon-bonded groups (except silicon-bonded hydrogen atoms) in component (B) include halogen-substituted or unsubstituted monovalent hydrocarbon groups (except alkenyl), such as C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl; C7-20 aralkyl groups, such as benzyl, phenethyl, and phenylpropyl; and any of these groups in which some or all of the hydrogen atoms are replaced by halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms. The silicon atoms in component (B) may also have a small amount of hydroxyl or alkoxy groups such as methoxy or ethoxy, provided that the purpose of the present invention is not impaired thereby. The silicon-bonded groups (except silicon-bonded hydrogen atoms) in component (B) may be selected from C1-6 alkyl groups, and particularly methyl groups.

[0082] In one embodiment of the present invention, the resinous organohydrogenpolysiloxane of component (B) may be represented by the following average unit formula (II):

[0083] Average unit formula (II): (R 2 3SiO 1 / 2 ) a (R 2 2SiO 2 / 2 ) b (R 2 SiO 3 / 2 ) c (SiO 4 / 2 ) d (XO 1 / 2 ) e

[0084] In formula (II), R 2 is a hydrogen atom, or a monovalent hydrocarbon group (except alkenyl) substituted or unsubstituted with the same or different halogen atoms, provided that at least two R 2 is 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. The symbol e represents the number of (XO) groups per silicon atom (ratio of the number of (XO) groups per silicon atom).

[0085] In formula (II), R 2Examples of the halogen-substituted or unsubstituted monovalent hydrocarbon groups (except alkenyl groups) include C1-12 alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups; C6-20 aryl groups such as phenyl, tolyl, xylyl, and naphthyl; C7-20 aralkyl groups such as benzyl, phenethyl, and phenylpropyl; and any of these groups in which some or all of the hydrogen atoms are substituted by halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms. 2 A small amount of hydroxyl groups or alkoxy groups such as methoxy groups or ethoxy groups may also be present, provided that the objects of the present invention are not thereby impaired. 2 It is preferably selected from a hydrogen atom and a C1-6 alkyl group, and particularly a methyl group.

[0086] X in the above formula (II) is a hydrogen atom or an alkyl group. Preferred examples of the alkyl group represented by X include C1-3 alkyl groups, specifically methyl, ethyl, and propyl groups. X is preferably a hydrogen atom.

[0087] 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.

[0088] Preferred embodiments of the present invention may or may not include R2SiO 1 / 2 The siloxane units (D units) represented by , and preferably do not contain these siloxane units.

[0089] In a preferred embodiment of the present invention, the resinous organohydrogenpolysiloxane of component (B) contains silicon-bonded hydrogen atoms at the molecular ends. 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 (specifically, D units and T units), and preferably does not contain silicon-bonded hydrogen atoms.

[0090] In a preferred embodiment of the present invention, the resinous organohydrogenpolysiloxane of component (B) may or may not contain an aryl group in the organic groups bonded to silicon atoms. Examples of the aryl group include C6-20 aryl groups such as phenyl, tolyl, xylyl, and naphthyl, and particularly phenyl.

[0091] When the resinous organohydrogenpolysiloxane of component (B) contains an aryl group, its content (mol% of the aryl group in all the functional groups bonded to silicon atoms of the resinous organohydrogenpolysiloxane) can be designed as required, 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.

[0092] In another embodiment of the present invention, the resinous organohydrogenpolysiloxane of component (B) does not contain an aryl group in the organic groups bonded to silicon atoms, or contains no more than 15 mol%, and at least 10 mol% or 5 mol% of an aryl group relative to all the functional groups bonded to silicon atoms.

[0093] In one embodiment of the present invention, component (B) comprises a resinous organohydrogenpolysiloxane and an MQ resinous organohydrogenpolysiloxane. The MQ resinous organohydrogenpolysiloxane can be represented by the following average unit formula (II-a):

[0094] Average unit formula (II-a): (R 2 3SiO 1 / 2 ) s (SiO 4 / 2 ) t (XO 1 / 2 ) u

[0095] In the formula, R 2 denotes a hydrogen atom, or a halogen-substituted or unsubstituted monovalent hydrocarbon group (except for an alkenyl group), which may be the same or different, provided that at least two R 2 per molecule are hydrogen atoms; 0 < s < 1, 0 < t < 1, 0 ≤ u < 0.4, and s + t = 1.0; and u is the number of (XO) groups per silicon atom (the ratio of the number of (XO) groups per silicon atom).

[0096] R 2 and X in the above formula (II-a) are as defined in the above formula (II), and the same definitions apply.

[0097] 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 the above 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.

[0098] In one embodiment of the present invention, the MQ resinous organohydrogensiloxane as component (B) does not contain an aryl group in the organic groups bonded to silicon atoms, or contains no more than 15 mol%, and at least 10 mol% or 5 mol% of aryl groups relative to all functional groups bonded to silicon atoms.

[0099] In one embodiment of the present invention, component (B) comprises a resinous organohydrogensiloxane and a resinous organohydrogensiloxane consisting only of M units and T units. The resinous organohydrogensiloxane consisting only of M units and T units can be represented by the following average unit formula (II-b):

[0100] Average unit formula (II-b): (R 2 3SiO 1 / 2 ) s (R 2 SiO 3 / 2 ) t (XO 1 / 2 ) u

[0101] In the formula, R 2 denotes a hydrogen atom, or a halogen-substituted or unsubstituted monovalent hydrocarbon group (except for an alkenyl group), which may be the same or different, provided that at least two R 2 per molecule are hydrogen atoms; 0 < s < 1, 0 < t < 1, 0 ≤ u < 0.4, and s + t = 1.0; and u is the number of (XO) groups per silicon atom (the ratio of the number of (XO) groups per silicon atom).

[0102] R 2 and X in the above formula (II-b) are as defined in the above formula (II).

[0103] 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 the above 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 the above 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.

[0104] In one embodiment of the present invention, the resinous organohydrogenpolysiloxane consisting only of M units and T units as component (B) may contain aromatic groups in the silicon atom-bonded organic groups, wherein the content (mol% of aromatic groups in all silicon atom-bonded functional groups of the resinous organohydrogenpolysiloxane) can be designed as needed, but is generally 5mol% or more, preferably 10mol% or more, and more preferably 15mol% or more, and may be 50mol% or less, preferably 40mol% or less, and more preferably 30mol% or less.

[0105] The viscosity of the resinous organohydrogenpolysiloxane of component (B) may be, for example, but not particularly limited to, in the range of 10 mPa to 1,000 mPa at 25° C. In this specification, the viscosity of the organopolysiloxane component may be determined at 25° C. using a rotational viscometer according to JIS K7117-1.

[0106] In one embodiment of the present invention, the number average molecular weight (Mn) of the resinous organohydrogenpolysiloxane of component (B) is preferably in the range of 500 to 3,000, and more preferably in the range of 600 to 2,000. In one embodiment of the present invention, the weight average molecular weight (Mw) of the resinous organohydrogenpolysiloxane of component (B) is preferably in the range of 500 to 3,000, and more preferably in the range of 600 to 2,000.

[0107] The content of the resinous organohydrogenpolysiloxane of component (B) is 5% by mass or more based on the total mass of the curable silicone composition of the present invention. The content of component (B) is also usually 30% by mass or less, preferably 20% by mass or less, and more preferably 15% by mass or less, based on the total mass of the curable silicone composition of the present invention.

[0108] (C) a linear organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule

[0109] Component (C) is a linear organohydrogenpolysiloxane which acts as a crosslinking agent for the curable silicone composition by a hydrosilylation curing reaction in the same manner as component (B) and has at least two silicon-atom-bonded hydrogen atoms per molecule. The curable silicone composition according to the present invention may contain one type of (C) linear organohydrogenpolysiloxane, or may contain two or more types of (C) linear organohydrogenpolysiloxanes.

[0110] Examples of silicon-bonded groups (except silicon-bonded hydrogen atoms) in component (C) include halogen-substituted or unsubstituted monovalent hydrocarbon groups (except alkenyl), such as C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl; C7-20 aralkyl groups, such as benzyl, phenethyl, and phenylpropyl; and any of these groups in which some or all of the hydrogen atoms are replaced by halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms. The silicon atoms in component (C) may also have a small amount of hydroxyl or alkoxy groups such as methoxy or ethoxy, provided that the purpose of the present invention is not impaired thereby. The silicon-bonded groups (except silicon-bonded hydrogen atoms) in component (C) may be selected from C1-6 alkyl groups, and particularly methyl groups.

[0111] In one embodiment of the present invention, component (C) may preferably be represented by:

[0112] Average structural formula (III): R 2 3SiO(R 2 2SiO 2 / 2 ) n S i 2 3

[0113] (In formula (III), R 2 is a hydrogen atom, or a halogen-substituted or unsubstituted monovalent hydrocarbon group (except alkenyl), which may be the same or different, provided that at least two R 2 is a hydrogen atom, and n is 1 to 200).

[0114] In the above formula (III), R 2 The halogen-substituted or unsubstituted monovalent hydrocarbon group (except alkenyl) represented by is as defined in the above formula (II), and the same definitions apply.

[0115] In formula (III), n is preferably 1 to 100, and more preferably 1 to 50. In another embodiment, the number of siloxane units in component (C) is generally in the range of 3 to 200, preferably 3 to 100, and more preferably 3 to 50.

[0116] In a preferred embodiment of the present invention, the linear organohydrogenpolysiloxane of component (C) has silicon-bonded hydrogen atoms at both ends of the molecular chain. The linear organohydrogenpolysiloxane of component (C) has silicon-bonded hydrogen atoms in the M units, and may or may not have silicon-bonded hydrogen atoms in the D units, but preferably has no silicon-bonded hydrogen atoms.

[0117] In one embodiment, component (C) may or may not contain an aryl group in the silicon atom-bonded organic group. Examples of the aryl group include C6-20 aryl groups such as phenyl, tolyl, xylyl, and naphthyl, and particularly phenyl.

[0118] When the linear organohydrogenpolysiloxane of component (C) contains an aromatic group, the content thereof (mol% of the aromatic group in all silicon atom-bonded functional groups of the linear organohydrogenpolysiloxane) can be designed as needed, but is generally 5 mol% or more, preferably 10 mol% or more, and more preferably 15 mol% or more, and may be 50 mol% or less, preferably 40 mol% or less, and more preferably 30 mol% or less.

[0119] The content of component (C) is not particularly limited, but is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on the total mass of the curable silicone composition. The content of component (C) is also generally 20% by mass or less, preferably 15% by mass or less, and more preferably 10% by mass or less, based on the total mass of the curable silicone composition.

[0120] In the present invention, the total content of (B) the resinous organohydrogenpolysiloxane and (C) the linear organohydrogenpolysiloxane is 13% by mass or more based on the total mass of the curable silicone composition of the present invention. The mass ratio of the content of the (B) resinous organohydrogenpolysiloxane to the content of the (C) linear organohydrogenpolysiloxane is also 0.8 or more, and preferably 0.85 or more. The mass ratio of the content of the (B) resinous organohydrogenpolysiloxane to the content of the (C) linear organohydrogenpolysiloxane is also typically 3 or less, preferably 2.5 or less, and more preferably 2 or less.

[0121] In one embodiment of the present invention, components may be included so that the ratio of silicon atom-bonded hydrogen atoms to silicon atom-bonded alkenyl groups (H / Al) in the organopolysiloxane component of the present invention is 0.7 mol or more, preferably 0.8 mol or more, more preferably 0.9 mol or more, and particularly 0.95 mol or more of silicon atom-bonded hydrogen atoms per mol of silicon atom-bonded alkenyl groups in the curable silicone composition, and components may also be included so that, for example, the ratio is 3 mol or less, preferably 2 mol or less, more preferably 1.7 mol or less, and more preferably 1.6 mol or less of silicon atom-bonded hydrogen atoms per mol of silicon atom-bonded alkenyl groups in the curable silicone composition.

[0122] (D) Curing catalyst

[0123] The curing catalyst of component (D) is a hydrosilylation reaction curing catalyst, which is a catalyst for promoting the curing of the curable silicone composition of the present invention. Examples of component (D) include platinum-based catalysts such as chloroplatinic acid, alcohol solutions of chloroplatinic acid, platinum-olefin complexes, complexes of platinum and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, and platinum-supported powders; palladium-based catalysts such as tetrakis(triphenylphosphine)palladium and a mixture of triphenylphosphine and palladium black; and rhodium-based catalysts; but platinum-based catalysts are particularly preferred.

[0124] Component (D) is blended in a catalytic amount; more specifically, when a platinum-based catalyst is used as component (D), the amount of platinum atoms is preferably 0.01 ppm or more, more preferably 0.1 ppm or more, and even more preferably 1 ppm or more, relative to the total mass of the curable silicone composition of the present invention, and may also preferably be 20 ppm or less, more preferably 15 ppm or less, and even more preferably 10 ppm or less, relative to the total mass of the curable silicone composition of the present invention.

[0125] (Other organopolysiloxane components)

[0126] The curable silicone composition according to the present invention may further contain an organopolysiloxane component in addition to components (A) to (C). Examples of such other organopolysiloxane components include linear alkenyl-containing organopolysiloxanes, organosiloxane oligomers having at least one epoxy group, and cerium-containing organopolysiloxanes.

[0127] The curable silicone composition according to the present invention may contain one or more linear alkenyl-containing organopolysiloxanes. The linear alkenyl-containing organopolysiloxane may preferably be represented by the following formula (IV):

[0128] Average structural formula (IV): R 1 3SiO(R1 2SiO 2 / 2 ) m S i 2 3

[0129] In formula (IV), R 1 is a halogen-substituted or unsubstituted monovalent hydrocarbon group, which may be the same or different, provided that at least two R 1 is alkenyl, and m is an integer of 1-500.

[0130] In the above formula (IV), the same R as in the above formula (I) can be used. 1 A halogen-substituted or unsubstituted monovalent hydrocarbon group.

[0131] In the above formula (IV), m is preferably 5 to 300, more preferably 10 to 250, and even more preferably 20 to 200.

[0132] Examples of such straight-chain alkenyl-containing organopolysiloxanes include dimethylpolysiloxane terminated with dimethylvinylsiloxy groups at both ends of the molecular chain, dimethylpolysiloxane terminated with diphenylvinylsiloxy groups at both ends of the molecular chain, dimethylsiloxane-methylphenylsiloxane copolymer terminated with dimethylvinylsiloxy groups at both ends of the molecular chain, dimethylsiloxane-diphenylsiloxane copolymer terminated with dimethylvinylsiloxy groups at both ends of the molecular chain, dimethylsiloxane-methylphenylsiloxane copolymer terminated with diphenylvinylsiloxy groups at both ends of the molecular chain, dimethylsiloxane-methylvinylsiloxane copolymer terminated with dimethylvinylsiloxy groups at both ends of the molecular chain, A dimethylsiloxane-methylphenylsiloxane-methylvinylsiloxane copolymer terminated with dimethylvinylsiloxy groups at both ends of the molecular chain, a dimethylsiloxane-diphenylsiloxane-methylvinylsiloxane copolymer terminated with dimethylvinylsiloxy groups at both ends of the molecular chain, a methylvinylpolysiloxane terminated with trimethylsiloxy groups at both ends of the molecular chain, a methylvinylsiloxane-methylphenylsiloxane copolymer terminated with trimethylsiloxy groups at both ends of the molecular chain, a methylvinylsiloxane-diphenylsiloxane copolymer terminated with trimethylsiloxy groups at both ends of the molecular chain, and a dimethylsiloxane-methylvinylsiloxane copolymer terminated with trimethylsiloxy groups at both ends of the molecular chain.

[0133] In a preferred embodiment of the present invention, the linear alkenyl-containing organopolysiloxane may be a linear organopolysiloxane having alkenyl groups at both molecular ends, wherein both ends of the molecular chain are terminated with alkenyl groups. The linear organopolysiloxane may or may not contain alkenyl groups on the molecular chain side chain (specifically, D unit), and preferably does not contain alkenyl groups.

[0134] The alkenyl content in the linear alkenyl-containing organopolysiloxane (mol% of alkenyl in all silicon atom-bonded functional groups of the linear organopolysiloxane) can be designed as needed, but can generally be 1 mol% or more, preferably 2 mol% or more, and more preferably 3 mol% or more, and can also be 20 mol% or less, preferably 15 mol% or less, and more preferably 10 mol% or less. The alkenyl content can be determined by analysis such as Fourier transform infrared spectrophotometry (FT-IR), nuclear magnetic resonance (NMR), and the titration method mentioned above.

[0135] In one embodiment, the straight chain alkenyl-containing organopolysiloxane may or may not contain an aryl group in the silicon-bonded organic group. Examples of aryl groups include C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl, and particularly phenyl. When the straight chain alkenyl-containing organopolysiloxane contains an aryl group (mol% of aryl groups in all silicon-bonded functional groups of the straight chain organopolysiloxane), its content can be designed as needed, but is generally 5mol% or more, preferably 10mol% or more, and more preferably 15mol% or more, and can also be 50mol% or less, preferably 40mol% or less, and more preferably 30mol% or less.

[0136] When the curable silicone composition of the present invention contains a straight-chain alkenyl group-containing organopolysiloxane, the content thereof is not particularly limited, but is generally 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, based on the total mass of the curable silicone composition of the present invention. The content of the straight-chain alkenyl group-containing organopolysiloxane is generally 50% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less, based on the total mass of the curable silicone composition of the present invention.

[0137] The curable silicone composition according to the present invention may include one type of organosiloxane oligomer having at least one epoxy group, or may include a combination of two or more types of organosiloxane oligomers having at least one epoxy group.

[0138] 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.

[0139] Examples of molecular structures of one or more organosiloxane oligomers having at least one epoxy group include linear, linear with some branches, branched, resinous, cyclic, and three-dimensional network structures. In one embodiment, the organosiloxane oligomer containing epoxy groups is a resinous organosiloxane oligomer containing epoxy groups.

[0140] The epoxy group-containing organosiloxane oligomer has at least one epoxy group. Examples of epoxy groups in the epoxy group-containing organosiloxane oligomer include: glycidyloxyalkyl groups such as 2-glycidyloxyethyl, 3-glycidyloxypropyl, and 4-glycidyloxybutyl; epoxycycloalkylalkyl groups such as 2-(3,4-epoxycyclohexyl)-ethyl and 3-(3,4-epoxycyclohexyl)-propyl; and epoxyalkyl groups such as 3,4-epoxybutyl and 7,8-epoxyoctyl.

[0141] Examples of the silicon atom-bonded organic group (other than the epoxy group) in the epoxy group-containing organosiloxane oligomer include: C1-12 alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C2-12 alkenyl groups such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl, and preferably vinyl; C6-12 aryl groups such as phenyl, tolyl, xylyl, and naphthyl; C7-12 aralkyl groups such as benzyl, phenethyl, and phenylpropyl; and any of these groups in which some or all of the hydrogen atoms are substituted by halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms. Silicon-bonded organic groups (except epoxy groups) preferably include C1-12 alkyl groups, and particularly methyl groups, or C2-12 alkenyl groups, and particularly vinyl groups. The epoxy group-containing organosiloxane oligomer may contain thiol groups.

[0142] In a preferred embodiment of the present invention, the epoxy group-containing organosiloxane oligomer contains at least one epoxy group and at least one alkenyl group, such as a vinyl group.

[0143] In one embodiment of the present invention, the epoxy group-containing organosiloxane oligomer is a resinous epoxy group-containing organosiloxane oligomer represented by the following average unit formula (V): 3 3SiO 2 / 2 ) f (R 3 2SiO 3 / 2 ) g (SiO 4 / 2 ) h (XO 1 / 2 ) i

[0144] {In formula (V), R 3 are each independently a halogen-substituted or unsubstituted monovalent hydrocarbon group, except that at least one R 3is an organic group containing an epoxy group; X is a hydrogen atom or an alkyl group, wherein the number satisfies 0≤f<1, 0≤g<1, 0≤h<0.95, 0≤i<0.4, f+g+h=1.0, and g+h>0. The symbol i represents the number of (XO) groups per silicon atom (ratio of the number of (XO) groups per silicon atom)}.

[0145] In the above formula (V), R 3 Examples of the halogen-substituted or unsubstituted monovalent hydrocarbon group represented by include the above-mentioned alkenyl groups, epoxy group-containing organic groups, and monovalent hydrocarbon groups other than these. Preferred examples of the alkyl group represented by X include C1-3 alkyl groups, specifically methyl, ethyl, and propyl groups.

[0146] 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.

[0147] In one embodiment of the present invention, the resinous epoxy-containing organosiloxane oligomer does not contain SiO 1 / 2 In another embodiment of the present invention, g in the above formula (V) is greater than 0; specifically, the resinous epoxy-containing organosiloxane oligomer contains SiO 3 / 2 The resinous epoxy group-containing organosiloxane oligomer may or may not contain SiO 4 / 2 In another embodiment of the present invention, i in the above formula (V) is greater than 0; specifically, the resinous epoxy-containing organosiloxane oligomer has at least one silicon-bonded -OX group. In one embodiment of the present invention, the resinous epoxy-containing organosiloxane oligomer consists only of D units and T units.

[0148] In another embodiment of the present invention, the organosiloxane oligomer containing epoxy groups is a condensation reaction product of at least one organosilane compound containing at least one epoxy group. Such condensation reaction products can be derived from one type of organosilane compound, or can be derived from two or more types of organosilane compounds. In other words, the structure of the organosiloxane oligomer containing epoxy groups contains units derived from an organosilane compound containing at least one epoxy group.

[0149] The condensation reaction may be a hydrolysis condensation reaction. Therefore, the epoxy group-containing organosiloxane oligomer may be a hydrolysis condensation reaction product.

[0150] The condensation degree of the condensation reaction may be, but is not particularly limited to, 2 to 20, preferably 3 to 15, and more preferably 3 to 10 siloxane units.

[0151] The organosilane compound containing at least one epoxy group may be a silane compound. Examples of the epoxy group contained in such an organosilane compound include the same epoxy groups mentioned above.

[0152] In one embodiment of the present invention, the organosilane compound can be represented by the following formula: (4-b) SiX b (In the formula, R indicates the same or different organic functional groups having at least one epoxy group, X indicates the same or different alkoxy groups, such as methoxy, ethoxy, and propoxy; oxime groups, such as acetone oxime or methyl ethyl ketoxime groups; amino groups, such as dimethylamino or diethylamino; amide groups, such as N-methylacetamide; aminooxy groups, such as diethylaminooxy; or alkenyloxy groups, such as isopropenyloxy; and b is 1, 2, or 3, preferably 2 or 3, and more preferably 3).

[0153] In the above formula representing the organosilane compound, X is preferably selected from an alkoxy group, and preferably a C1-C6 alkoxy group, such as a methoxy group, an ethoxy group, and a propoxy group.

[0154] The organosilane compound may be a silane coupling agent. Examples of such organosilane compounds include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, glycidoxypropyl(dimethoxy)methylsilane, glycidoxypropyl(trimethoxy)silane, and 2-(3,4-epoxy)cyclohexyl)ethyltrimethoxysilane.

[0155] In a specific embodiment of the present invention, the epoxy group-containing organosiloxane oligomer is a condensation reaction product of 2 to 20 glycidoxypropyltrimethoxysilanes, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, glycidoxypropyl(dimethoxy)methylsilane, glycidoxypropyl(trimethoxy)silane, 2-(3,4-epoxy)cyclohexyl)ethyltrimethoxysilane, glycidoxypropyl(trimethoxy)silane, or any combination thereof, especially a condensation reaction product of four glycidoxypropyl(trimethoxy)silanes.

[0156] In yet another embodiment of the present invention, the epoxy-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 containing at least one organic functional group other than an epoxy group, or an oligomer thereof. In one embodiment, the epoxy-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 containing at least one ethylenically unsaturated group such as an alkenyl group (e.g., a vinyl group), or an oligomer thereof.

[0157] In yet another embodiment of the present invention, the epoxy group-containing organosiloxane oligomer is a condensation reaction product of: a vinyl group-containing organosiloxane oligomer capped with silanol groups at both ends of the molecule; and 3-glycidoxypropyltrimethoxysilane.

[0158] The amount of the epoxy group-containing organic group in all silicon atom-bonded organic groups in the epoxy group-containing organopolysiloxane may be, for example, but not particularly limited to, 3 mol% or more, preferably 5 mol% or more, and more preferably 10 mol% or more, and is usually 50 mol% or less, preferably 40 mol% or less, and more preferably 30 mol% or less. The amount of the epoxy group-containing organic group may be determined by analysis such as Fourier transform infrared spectrophotometry (FT-IR) or nuclear magnetic resonance (NMR).

[0159] The weight average molecular weight (Mw) of the epoxy group-containing organosiloxane oligomer is not particularly limited, but may range from 500 to 3,000, and preferably from 800 to 2,000.

[0160] As used in this specification, the weight average molecular weight can be determined by GPC.

[0161] The content of the epoxy group-containing organopolysiloxane is not particularly limited, but may be an amount of preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and still more preferably 0.3% by mass or more, based on the total mass of the curable silicone composition of the present invention, and may also be an amount of 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, based on the total mass of the curable hot-melt silicone composition of the present invention.

[0162] The cerium-containing organopolysiloxane can be prepared, for example, by the reaction between cerium chloride or a cerium salt of a carboxylic acid and an alkali metal salt of an organopolysiloxane containing a silanol group. Therefore, as used in this specification, the term "cerium-containing organopolysiloxane" may mean a substance obtained by reacting an organopolysiloxane containing a silanol group with a cerium salt, wherein the silanol group of the organopolysiloxane is chemically bonded to a cerium atom.

[0163] Examples of cerium salts of carboxylic acids include cerium 2-ethylhexanoate, cerium naphthenate, cerium oleate, cerium laurate, and cerium stearate. An example of cerium chloride is cerium trichloride.

[0164] Examples of the alkali metal salt of the silanol group-containing organopolysiloxane include a potassium salt of a diorganopolysiloxane terminated with a silanol group at both ends of the molecular chain, a sodium salt of a diorganopolysiloxane terminated with a silanol group at both ends of the molecular chain, a potassium salt of a diorganopolysiloxane terminated with a silanol group at one end of the molecular chain and with a triorganosiloxy group at the other end of the molecular chain, and a sodium salt of a diorganopolysiloxane terminated with a silanol group at one end of the molecular chain and with a triorganosiloxy group at the other end of the molecular chain. Furthermore, examples of silicon atom-bonded groups in these organopolysiloxanes include C1-12 alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; C6-20 aryl groups such as phenyl, tolyl, xylyl, and naphthyl; C7-20 aralkyl groups such as benzyl, phenethyl, and phenylpropyl; and any of these groups in which some or all of the hydrogen atoms are substituted by halogen atoms such as fluorine atoms, chlorine atoms, or bromine atoms.

[0165] The above reaction is carried out at room temperature or in alcohol such as methanol, ethanol, isopropanol or butanols, aromatic hydrocarbons such as toluene or dimethylbenzene, aliphatic hydrocarbons such as hexane or heptane, or organic solvents such as mineral solvents, light petroleum or sherwood oil. The gained reaction product is preferably processed by distilling out organic solvent or low boiling point component or filtering out sediment as required. Also dialkylformamide, hexaalkylphosphoramide etc. can be added to promote reaction. The cerium atom content of the cerium-containing organopolysiloxane obtained thus is preferably in the scope of 0.1 mass % to 15 mass %.

[0166] The content of the cerium-containing organopolysiloxane is not particularly limited, but is preferably 0.1% by mass or more, and more preferably 0.3% by mass or more, based on the total mass of the curable silicone composition of the present invention. The cerium-containing organopolysiloxane is also generally contained in an amount of 5% by mass or less, and preferably 3% by mass or less, based on the total mass of the curable silicone composition.

[0167] (Other components)

[0168] Optional components can be blended into the curable silicone composition of the present invention, provided that the purpose of the present invention is not impaired. Optional examples of components include acetylene compounds, organophosphorus compounds, vinyl-containing siloxane compounds; inorganic fillers, such as crushed quartz, silicon dioxide, magnesium carbonate, diatomaceous earth, and inorganic fillers obtained by subjecting the surface of such inorganic fillers to hydrophobic treatment with organosilicon compounds; surface treatment agents, hydrosilylation reaction inhibitors, tackifiers, agents imparting heat resistance, agents imparting cold resistance, agents imparting flame retardancy, agents imparting thixotropic properties, phosphors, and solvents. Such optional components are usually added in an amount of 0.001% to 20% by mass of the total composition.

[0169] Hydrosilylation reaction inhibitors are components used to inhibit the hydrosilylation reaction of curable silicone compositions. Examples of such curing reaction inhibitors include: alkynols such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 2-phenyl-3-butyn-2-ol, 1-ethynyl-1-cyclohexanol, and 1-ethynyl-2-cyclohexanol; enyne compounds such as 3-methyl-3-pentene-1-yne, 3,5-dimethyl-3-hexene-1-yne; low molecular weight siloxanes containing alkenyl groups such as tetramethyltetravinylcyclotetrasiloxane and tetramethyltetrahexenylcyclotetrasiloxane; and alkynyloxysilanes such as methyl-tris(1,1-dimethylpropynyloxy)silane, vinyl-tris(1,1-dimethylpropynyloxy)silane, and methyl-tris-(3-methyl-1-butyn-3-oxy)silane. The hydrosilylation reaction inhibitor is preferably selected from acetylenic alcohols, and particularly preferably 1-ethynyl-1-cyclohexanol. The reaction inhibitor is usually added in an amount of 0.001% to 5% by mass of the total composition.

[0170] The curable silicone composition according to the present invention can be cured to form a cured product having excellent transparency. Specifically, the cured product of the curable silicone composition of the present invention is highly transparent even after being heated, with almost no yellowing. For example, even after being kept at 150° C. for 48 hours, 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 a wavelength of 400 nm to 700 nm. The light transmittance of the cured product of the curable silicone composition can be determined, for example, by analyzing the cured product using a spectrophotometer.

[0171] The curable silicone composition of the present invention can be effectively cured for practical purposes even at low temperatures, and can be cured quickly to form a cured product with little shape change or shrinkage upon curing. The curable silicone composition of the present invention can be heated to a temperature of, for example, 50° C. to 150° C., preferably 60° C. to 120° C., and more preferably 70° C. to 100° C. for 30 seconds or more, and preferably 45 seconds or more to form a cured product.

[0172] The curable silicone composition of the present invention can be prepared by mixing the various components. The method for mixing the components can be a conventional known method, but is not particularly limited; for example, the composition can be prepared using a mixing device. Examples of such mixing devices include, but are not particularly limited to, single-screw and twin-screw continuous mixers, twin-roll mixers, Ross mixers, Hobart mixers, dental mixers, planetary mixers, kneading mixers, and Henschel mixers.

[0173] [Encapsulant]

[0174] The present invention also relates to an encapsulant for semiconductors comprising the curable silicone composition of the present invention. The present invention also relates to an encapsulation material obtained by curing the encapsulant of the present invention. Specifically, the encapsulation material of the present invention may comprise a cured product of the curable silicone composition of the present invention.

[0175] The configuration of the encapsulating material of the present invention is not particularly limited, but is preferably dome-shaped or in the form of a sheet. Examples of semiconductors that can be encapsulated by the encapsulant, encapsulating material or film of the present invention include, but are not particularly limited to, semiconductors such as SiC and GaN semiconductors, and particularly optical semiconductors such as power semiconductors and light emitting diodes.

[0176] [Optical semiconductor elements]

[0177] The present invention also relates to an optical semiconductor element encapsulated with a cured product of the encapsulant of the present invention. Specifically, the optical semiconductor element of the present invention comprises a cured product of the encapsulant of the present invention. Examples of optical semiconductor elements include light emitting diodes (LEDs), semiconductor lasers, photodiodes, phototransistors, and light emitters and light receivers for solid-state imaging, and photocouplers, wherein light emitting diodes (LEDs) are particularly preferred.

[0178] The light emitting diode (LED) generates emission light from the upper side, lower side, left side and right side of the optical semiconductor element, so it is not desirable for the components of the light emitting diode (LED) to absorb light, and materials with high transmittance or high reflectance are preferred for such components. Therefore, the substrate on which the optical semiconductor element is mounted also preferably includes a material with high transmittance or high reflectance. Examples of substrates on which the optical semiconductor element is 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 aluminum oxide and aluminum nitride.

[0179] Specific embodiments of the present invention are presented below.

[0180] Embodiment 1: A curable silicone composition comprising:

[0181] (A) an MQ resinous alkenyl-containing organopolysiloxane having at least two alkenyl groups per molecule;

[0182] (B) a resinous organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule;

[0183] (C) a linear organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule; and

[0184] (D) a curing catalyst,

[0185] in

[0186] (B) the content of the resinous organohydrogenpolysiloxane is 5% by mass or more relative to the total mass of the composition,

[0187] The total content of (B) the resinous organohydrogenpolysiloxane and (C) the linear organohydrogenpolysiloxane is 13% by mass or more relative to the total mass of the composition, and

[0188] The mass ratio of the content of the (B) resinous organohydrogenpolysiloxane to the content of the (C) linear organohydrogenpolysiloxane is 0.8 or more.

[0189] Embodiment 2: The curable silicone composition according to embodiment 1, wherein the content of (A) MQ resinous alkenyl-containing organopolysiloxane is 30% to 80% by mass.

[0190] Embodiment 3: The curable silicone composition according to embodiment 1 or 2, wherein (B) the resinous organohydrogenpolysiloxane has a network molecular structure.

[0191] Embodiment 4: The curable silicone composition of any one of Embodiments 1 to 3, wherein (B) the resinous organohydrogenpolysiloxane comprises an MQ resinous organohydrogenpolysiloxane and / or a resinous organohydrogenpolysiloxane consisting only of M units and T units.

[0192] Embodiment 5: The curable silicone composition of any one of Embodiments 1 to 4, wherein the mass ratio of the content of (B) the resinous organohydrogenpolysiloxane to the content of (C) the linear organohydrogenpolysiloxane is 3 or less.

[0193] Embodiment 6: A packaging material for a semiconductor, which is composed of the curable silicone composition according to any one of Embodiments 1 to 5.

[0194] Embodiment 7: An optical semiconductor device comprising the packaging material according to Embodiment 6.

[0195] [Example]

[0196] The curable silicone composition of the present invention is described in detail by means of the following examples and comparative examples.

[0197] The curable silicone composition is prepared by mixing the components (by mass) in the formulation shown in the table. Hereinafter, Me represents a methyl group, Vi represents a vinyl group, and Ep represents a 3-glycidyloxypropyl group. The structure of the organopolysiloxane component is also shown in the table in a simplified manner, and the functional groups other than Me in the M, D, or T units are shown in brackets. H / Vi indicates the molar ratio of the hydrogen atoms (H) bonded to the silicon atoms in the organopolysiloxane component to the vinyl group (Vi). In the specification of the present application, a "unit formula" indicates a unit consisting of (SiO x / 2 ) (x is an integer from 1 to 4), and "Structural Formula" indicates a chemical formula not including any such siloxane unit. In the table, "nd" means not determined.

[0198] Component a-1: composed of the average unit formula (Me3SiO 1 / 2 ) 42 (ViMe2SiO 1 / 2 )7(SiO 4 / 2 ) 51MQ resinous alkenyl-containing organopolysiloxane represented by (OH)4 (solid at 25°C; number of siloxane units = 55; number average molecular weight (Mn) = 3900; weight average molecular weight (Mw) = 5400)

[0199] Component a-2: average structural formula ViMe2SiO(M2SiO) 40 Straight chain alkenyl-containing organopolysiloxane represented by SiMe2Vi

[0200] Component a-3: average structural formula ViMe2SiO(M2SiO) 150 Straight chain alkenyl-containing organopolysiloxane represented by SiMe2Vi

[0201] Component a-4: composed of the average unit formula (Me3SiO 1 / 2 ) 39 (ViMe2SiO 1 / 2 )6(SiO 4 / 2 ) 55 MQ resinous alkenyl-containing organopolysiloxane (solid at 25°C)

[0202] Component b-1: The average unit formula (Me2HSiO 1 / 2 ) 62 (SiO 4 / 2 ) 38 MQ resinous organohydrogen polysiloxane (number average molecular weight (Mn) = 1300; weight average molecular weight (Mw) = 1700; network molecular structure)

[0203] Component b-2: The average unit formula (Me2HSiO 1 / 2 ) 60 (PhSiO 3 / 2 ) 40 Resinous organohydrogen polysiloxane (number average molecular weight (Mn) = 700; weight average molecular weight (Mw) = 750; network molecular structure)

[0204] Component c-1: average structural formula Me2HSiO(Me2SiO) 20 Straight chain organohydrogen polysiloxane represented by SiHMe2

[0205] Component c-2: a linear organohydrogenpolysiloxane represented by the average structural formula Me2HSiO(Ph2SiO)SiHMe2

[0206] Component d: a complex of platinum and divinyltetramethyldisiloxane having a platinum concentration of 3.0 mass %

[0207] Component e: a vinyl-containing organosiloxane oligomer terminated with silanol groups at both ends of the molecule (composed of an average unit formula (EpSiO 3 / 2 ) a (MeViSiO 2 / 2 ) b (Me2SiO 2 / 2 ) c (OX) d The condensation reaction product of 3-glycidyloxypropyltrimethoxysilane (weight average molecular weight: 1280)

[0208] Component f: cerium-containing dimethylpolysiloxane having a cerium content of 1.4% by mass

[0209] Component g: 1-ethynyl-1-cyclohexanol

[0210] The following evaluations were performed.

[0211] [Curing property]

[0212] The obtained curable silicone composition was analyzed using a vulcanizer (moving die rheometer (MDR)) to determine the time from immediately after the determined value to the maximum torque at a temperature of 90°C.

[0213] [Light transmittance of cured product]

[0214] 3 g of the obtained curable silicone composition was heated to 90° C. for 5 minutes using a mold (10 mm×50 mm×2 mm) to prepare a 2 mm thick cured product. The cured product was aged at 150° C. for 48 hours, and then the transmittance (450 nm wavelength) was determined at 25° C. A transmittance of 95% or more was evaluated as OK.

[0215] [Curing shrinkage]

[0216] 15 g of the obtained curable silicone composition was pressed at 90° C. for 5 minutes using a mold (10 cm×15 cm×1 mm) to produce a cured product, which was cooled to ambient temperature, the dimensions were measured, and the percentage of dimensional change was used as the curing shrinkage. A curing shrinkage of 1.0% or less was evaluated as OK. The curing shrinkage corresponds to the volume shrinkage that occurs when the composition is cured.

[0217] [Die shear strength]

[0218] The silicone composition was used to fill an annular space (8 mm diameter x 200 um depth) in a 25 mm x 75 mm aluminum sheet substrate, an aluminum chip was placed thereon, and the composition was then cured at 90°C for 5 minutes to bond the chip to the substrate. The uncured composition was cured at 90°C until cured. The die shear strength was determined using a bond tester (model: SS-30WD; test mode: PH50 push; speed: 0.120 mm / sec).

[0219] [Table 1]

[0220]

[0221] [Table 2]

[0222]

[0223] The results in Table 1 show that the curable silicone composition of the present invention can be cured within 5 minutes even at a low temperature of 90° C., making it possible to form cured products that do not shrink too much when cured, maintain high transparency even after aging at high temperatures, and have excellent adhesive strength. The results in Table 2 show that Comparative Examples 1 to 5 and 7 (outside the scope of the present invention) require more than 5 minutes when cured via heat treatment at 90° C. The cured product of Comparative Example 7 also has poor adhesive strength.

[0224] [Industrial Applicability]

[0225] The curable silicone composition of the present invention can be used as an encapsulation material or a coating material for optical semiconductor elements such as light emitting diodes (LEDs).

Claims

1. A curable silicone composition comprising: (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; and (D) a curing catalyst, in The content of the (B) resinous organohydrogenpolysiloxane is 5% by mass or more relative to the total mass of the composition, The total content of (B) the resinous organohydrogenpolysiloxane and (C) the linear organohydrogenpolysiloxane is 13% by mass or more relative to the total mass of the composition, and The mass ratio of the content of the (B) resinous organohydrogenpolysiloxane to the content of the (C) linear organohydrogenpolysiloxane is 0.8 or more.

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

3. The curable silicone composition according to claim 1 or 2, wherein: The (B) resinous organohydrogenpolysiloxane has a network molecular structure.

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

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

6. An encapsulation material for a semiconductor, which is composed of the curable silicone composition according to any one of claims 1 to 5. 7 . An optical semiconductor device comprising the packaging material according to claim 6 .

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