Curable silicone composition, sealing material and optical semiconductor device

Abstract

To provide a curable silicone composition capable of forming a cured product which has excellent transparency, high hardness and strength and is improved in crack resistance to temperature changes.SOLUTION: There is provided a curable silicone composition which comprises (A) a resinous alkenyl group-containing organopolysiloxane; (B) at least one organopolysiloxane selected from the following (B-1) and (B-2): (B-1) a linear organopolysiloxane containing at least two hydrogen atoms bonded to silicon atoms per molecule or at least two alkenyl groups per molecule at the molecular chain terminal and containing 7 or more and 35 or less siloxane units; (B-2) a resinous organohydrogen polysiloxane containing at least two hydrogen atoms bonded to silicon atoms per molecule; (C) a silicone reactive compatibilizer, which is an organopolysiloxane having 6 or less siloxane units; (D) a curing catalyst; and (E) a reaction inhibitor.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable silicone composition, more specifically to a curable silicone composition suitable for use as an encapsulant for optical semiconductors. The present invention also relates to an optical semiconductor device encapsulated with an encapsulant made of a cured product of such a curable silicone composition. [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 susceptible to discoloration than other organic materials and show little deterioration in physical properties such as durability, so they are widely used as silicone encapsulants for optical materials, particularly in optical semiconductor devices such as light-emitting diodes (LEDs).

[0003] For example, Patent Document 1 describes (A) a polysiloxane having at least one silicon-bonded alkenyl group and at least one silicon-bonded aryl group per molecule, and having the general formula: RSiO 3 / 2 (B) a linear organopolysiloxane having siloxane units of the formula: (wherein R is a substituted or unsubstituted monovalent hydrocarbon group), (C) a hydrosilylation reaction catalyst, and (D) a linear organopolysiloxane having at least one silicon-bonded alkenyl group per molecule and having an average formula of: (R 5 3SiO 1 / 2 ) f (R 5 2SiO 2 / 2 ) g (R 5 SiO 3 / 2 ) h (SiO 4 / 2 ) i (In the formula, each R 5 may be the same or different and are independently selected from substituted or unsubstituted monovalent hydrocarbon groups, and there is at least one R per molecule.5 is an alkenyl group, with the proviso that the ratio of alkenyl groups to silicon atoms is 0.3:1, and f, g, h, and i are independently 0 or a positive number), wherein the weight average molecular weight Mw of the siloxane is less than 1,000 g / mol.

[0004] Furthermore, Patent Document 2 discloses (A) a siloxane unit of the following chemical formula A and a siloxane unit of the following chemical formula B: [Chemical formula A] (R a 3SiO 1 / 2 ) [Chemical formula B] (R b R a 2SiO 1 / 2 ) (R in chemical formulas A and B) a is an alkyl group, and R b is an alkenyl group), a ratio (B / (A+B)) of the number of moles (B) of the siloxane units of the chemical formula B to the total number of moles (A+B) of the siloxane units of the chemical formulas A and B is within the range of 0.1 to 0.35, and a molar ratio (Ar) of aryl groups (Ar) to silicon atoms (Si) is 0.3 or less; and a first crosslinked polyorganosiloxane containing siloxane units of the following chemical formula A and siloxane units of the following chemical formula B, wherein the number of moles (A) of the siloxane units of the chemical formula B to the total number of moles (A+B) of the siloxane units of the chemical formulas A and B ( The document also describes a mixture of a second crosslinked polyorganosiloxane in which the ratio (B / (A+B)) of (A) to (B) the first crosslinked polyorganosiloxane is different from that of the first crosslinked polyorganosiloxane and is within the range of 0.2 to 1, and the molar ratio (Ar / Si) of aryl groups (Ar) to silicon atoms (Si) is 0.3 or less, and a curable composition containing (B) a polyorganosiloxane containing hydrogen atoms and aryl groups bonded to silicon atoms, in which the molar ratio of aryl groups (Ar) to silicon atoms (Si) is 0.25 or more and the number of silicon atoms is within the range of 3 to 10.

[0005] However, conventional curable silicone compositions have had problems such as insufficient hardness and strength of the cured product, and poor thermal stability. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2019-524959 [Patent Document 2] Special Publication No. 2016-520679 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a curable silicone composition that can form a cured product that has excellent transparency, high hardness and strength, and improved crack resistance when subjected to temperature changes.

[0008] Another object of the present invention is to provide an encapsulant obtained by curing the curable silicone composition of the present invention. Still another object of the present invention is to provide an optical semiconductor device encapsulated with the encapsulant of the present invention. [Means for solving the problem]

[0009]

[0013] In order to solve the above problems, the present inventors conducted extensive research and discovered that a curable organopolysiloxane composition comprising at least the specified components (A) to (E) of the present invention and satisfying the following specified conditions can form a cured product that has excellent transparency, high hardness and strength, and improved crack resistance against temperature changes, and thus arrived at the present invention.

[0010] Therefore, the present invention provides (A) A resinous alkenyl group-containing organopolysiloxane comprising the following (A-1) and (A-2): (A-1) A resinous alkenyl-containing organopolysiloxane containing at least two alkenyl groups and at least one aryl group per molecule. (A-2) an MQ resin-like alkenyl group-containing organopolysiloxane that is solid at 25°C and contains at least two alkenyl groups per molecule and does not contain any aryl groups; (B) At least one organopolysiloxane selected from the following (B-1) and (B-2): (B-1) A linear organopolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule or at least two alkenyl groups per molecule at its molecular chain terminals, and containing 7 to 35 siloxane units. (B-2) a resinous organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule; (C) a silicone reactive compatibilizer which is an organopolysiloxane having 6 or less siloxane units selected from (C-1) a linear organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms and at least one aryl group per molecule, (C-2) an MQ resinous organopolysiloxane containing at least two alkenyl groups per molecule, and (C-3) a cyclic organopolysiloxane containing at least two alkenyl groups per molecule; (D) a curing catalyst; and (E) Reaction inhibitor 1. A curable silicone composition comprising: the content of aryl groups in the component (A-1) is more than 0% by mass and 30% by mass or less, relative to the total mass of the component (A-1); (B) the organopolysiloxane comprises at least one organohydrogenpolysiloxane; when the component (C) contains the component (C-1), the content of the component (C-1) is 20% by mass or more and 48% by mass or less based on the total amount of the component (A-1) and the component (C-1); a resinous alkenyl group-containing organopolysiloxane having at least two alkenyl groups and at least one aryl group per molecule, wherein the content of the resinous alkenyl group-containing organopolysiloxane containing aryl groups in an amount greater than 30% by weight is 15% by weight or less based on the total weight of the curable silicone composition; The present invention relates to a curable silicone composition in which the content of linear organopolysiloxanes containing more than 35 siloxane units is 15% by weight or less, based on the total weight of the curable silicone composition.

[0011] The content of component (A-1) is preferably 5 to 50 mass % based on the total mass of the curable silicone composition of the present invention.

[0012] It is preferable to include the component (C-1).

[0013] The total content of component (C) is preferably 3 to 50 mass % based on the total mass of the curable silicone composition.

[0014] The combined amount of components (A-2) and (B-1) is preferably at least 20% by weight based on the total weight of the curable silicone composition of the present invention.

[0015] The total content of the component (C) is preferably 10% by mass or more based on the combined content of the components (A-2), (B-1), and (C).

[0016] The content of the component (A-1) is preferably 60 mass % or less based on the total content of the components (A-1), (A-2), and (B-1).

[0017] The present invention also relates to a sealant or adhesive comprising the curable silicone composition of the present invention.

[0018] The present invention also relates to an optical semiconductor device encapsulated with the encapsulant according to the present invention. [Effects of the Invention]

[0019] The curable silicone composition of the present invention can form a cured product that has excellent transparency, high hardness and strength, and improved resistance to cracking due to temperature changes. DETAILED DESCRIPTION OF THE INVENTION

[0020] [Curable Silicone Composition] The curable silicone composition according to the present invention comprises: (A) A resinous alkenyl group-containing organopolysiloxane comprising the following (A-1) and (A-2): (A-1) A resinous alkenyl-containing organopolysiloxane containing at least two alkenyl groups and at least one aryl group per molecule. (A-2) an MQ resin-like alkenyl group-containing organopolysiloxane that is solid at 25°C and contains at least two alkenyl groups per molecule and does not contain any aryl groups; (B) At least one organopolysiloxane selected from the following (B-1) and (B-2): (B-1) A linear organopolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule or at least two alkenyl groups per molecule at its molecular chain terminals and containing 35 or less siloxane units. (B-2) a resinous organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule; (C) a silicone reactive compatibilizer which is an organopolysiloxane having an average mass molecular weight of less than 750, selected from (C-1) a linear organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms and at least one aryl group per molecule, (C-2) an MQ resinous organopolysiloxane containing at least two alkenyl groups per molecule, and (C-3) a cyclic organopolysiloxane containing at least two alkenyl groups per molecule; (D) a curing catalyst; and (E) Reaction inhibitor 1. A curable silicone composition comprising: the content of aryl groups in the component (A-1) is more than 0% by mass and 30% by mass or less, relative to the total mass of the component (A-1); (B) the organopolysiloxane comprises at least one organohydrogenpolysiloxane; when the component (C) contains the component (C-1), the content of the component (C-1) is 20% by mass or more and 48% by mass or less based on the total amount of the component (A-1) and the component (C-1); a resinous alkenyl group-containing organopolysiloxane having at least two alkenyl groups and at least one aryl group per molecule, wherein the content of the resinous alkenyl group-containing organopolysiloxane containing aryl groups in an amount greater than 30% by weight is 15% by weight or less based on the total weight of the curable silicone composition; The curable silicone composition has a linear organopolysiloxane content of more than 35 siloxane units of 15% by weight or less, based on the total weight of the curable silicone composition.

[0021] Each component of the curable silicone composition of the present invention will now be described in detail.

[0022] (A) Resinous alkenyl-containing organopolysiloxane Component (A) is a resin-like alkenyl-group-containing organopolysiloxane having at least two alkenyl groups per molecule, and includes at least (A-1) a resin-like alkenyl-group-containing organopolysiloxane containing at least two alkenyl groups and at least one aryl group per molecule, and (A-2) an MQ resin-like alkenyl-group-containing organopolysiloxane that is solid at 25°C and contains at least two alkenyl groups per molecule but no aryl groups.

[0023] In this specification, the term "resin-like" means that the molecular structure has a branched or three-dimensional network structure. Therefore, resin-like organopolysiloxanes have R-SiO 3 / 2 Siloxane units (T units) represented by the formula: and / or SiO 4 / 2In one embodiment, resinous organopolysiloxanes contain siloxane units (Q units) represented by the formula: In one embodiment, resinous organopolysiloxanes contain 10% or more, preferably 20% or more, and more preferably 30% or more of T and Q units relative to the total siloxane units in one molecule. In this specification, R in the siloxane units represents a silicon-bonded organic group, such as a monovalent hydrocarbon group.

[0024] In this specification, MQ resin-like material refers to R3-SiO 1 / 2 Siloxane units (M units) represented by the formula: and SiO 4 / 2 This means an organopolysiloxane consisting only of siloxane units (Q units) represented by the following formula:

[0025] Examples of alkenyl groups contained in component (A) include alkenyl groups having 2 to 12 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl, with vinyl being preferred. Examples of aryl groups include aryl groups having 6 to 20 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl.

[0026] The silicon-bonded organic groups other than alkenyl and aryl groups contained in component (A) include halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl and aryl groups. Examples include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; and groups in which some or all of the hydrogen atoms in these groups have been substituted with halogen atoms such as fluorine, chlorine, or bromine. The silicon atoms in component (A) may contain small amounts of hydroxyl groups or alkoxy groups such as methoxy and ethoxy, provided that the objectives of the present invention are not impaired. The silicon-bonded organic groups other than alkenyl groups in component (A) are preferably alkyl groups having 1 to 6 carbon atoms, particularly methyl groups. In one embodiment, component (A) does not include an epoxy group-containing organic group as an organic group bonded to a silicon atom.

[0027] The alkenyl-containing resinous organopolysiloxane of component (A) may be intended to be a resinous alkenyl-containing organopolysiloxane that does not contain epoxy-containing organic groups as the organic groups bonded to silicon atoms.

[0028] (A-1) A resinous alkenyl-containing organopolysiloxane containing at least two alkenyl groups and at least one aryl group per molecule. The curable silicone composition according to the present invention contains, as component (A), (A-1) an alkenyl-containing resinous organopolysiloxane containing at least two alkenyl groups and at least one aryl group per molecule. The composition may contain one type of (A-1) alkenyl-containing resinous organopolysiloxane, or two or more types of (A-1) alkenyl-containing resinous organopolysiloxanes.

[0029] In one embodiment of the present invention, the component (A-1) may preferably be represented by the following average unit formula (I): Average unit formula (I): (R1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d (XO 1 / 2 ) e (In formula (I), 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 at least one R 1 is an aryl group, and can be expressed by the formula (where 0≦a<1, 0≦b<1, 0≦c<0.9, 0≦d<0.5, and 0≦e<0.4, a+b+c+d=1.0, and c+d>0). e represents the number of (XO) groups (the ratio of the number of (XO) groups to the total number of silicon atoms) when the total number of silicon atoms is 1. In addition, in this specification, the term "unit formula" refers to (SiO x / 2 ) (where x is an integer of 1 to 4), and the "structural formula" is a chemical formula that shows the actual number of siloxane units in the molecule.

[0030] R in the above formula (I) 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; 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; alkenyl groups having 2 to 12 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms, such as fluorine, chlorine, or bromine. R 1 is preferably selected from alkyl groups having 1 to 6 carbon atoms, particularly a methyl group; alkenyl groups having 2 to 6 carbon atoms, particularly a vinyl group; and aryl groups having 6 to 20 carbon atoms, particularly a phenyl group.

[0031] In the above formula (I), X is a hydrogen atom or an alkyl group. The alkyl group for X is preferably an alkyl group having 1 to 3 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, and a propyl group.

[0032] In the above formula (I), a is preferably in the range of 0.1≦a≦0.6, more preferably in the range of 0.15≦a≦0.5, and even more preferably in the range of 0.2≦a≦0.4. In the above formula (I), b is preferably in the range of 0≦b≦0.3, more preferably in the range of 0≦b≦0.2, and particularly in the range of 0≦b≦0.1. In the above formula (I), c is preferably in the range of 0.4≦c<0.9, more preferably in the range of 0.5≦c≦0.85, and particularly in the range of 0.6≦c≦0.8. In the above formula (I), d is preferably in the range of 0≦d≦0.3, more preferably in the range of 0≦d≦0.5, and particularly in the range of 0≦d≦0.1. In the above formula (I), 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.

[0033] In a preferred embodiment of the present invention, the resinous alkenyl group-containing organopolysiloxane of component (A-1) is one represented by formula (I) above, where c is greater than 0, i.e., it contains at least one T unit. The resinous organopolysiloxane of component (A-1) may or may not contain Q units, but preferably does not contain them.

[0034] In a preferred embodiment of the present invention, the resinous alkenyl group-containing organopolysiloxane of component (A-1) is R—SiO 2 / 2 The siloxane unit (D unit) represented by the following formula (1) may or may not be contained, but preferably is not contained.

[0035] In a preferred embodiment of the present invention, the resinous alkenyl group-containing organopolysiloxane of component (A-1) is R—SiO 1 / 2 The organopolysiloxane is an MT resin-like alkenyl-containing organosiloxane consisting only of siloxane units (M units) represented by the formula (I) and T units.

[0036] In a preferred embodiment of the present invention, the alkenyl-containing resinous organopolysiloxane of component (A-1) contains alkenyl groups at the molecular terminals. The resinous organopolysiloxane of component (A-1) preferably has alkenyl groups in the M units, and may or may not contain alkenyl groups in molecular side chains (i.e., D units and T units), but preferably does not.

[0037] The alkenyl group content of all silicon-bonded organic groups in the resinous alkenyl-group-containing organopolysiloxane of component (A-1) is not particularly limited, but may be, for example, 1 mol% or more, preferably 3 mol% or more, more preferably 5 mol% or more of the total silicon-bonded organic groups, and 30 mol% or less, preferably 20 mol% or more, more preferably 15 mol% or less of the total silicon-bonded organic groups. In this specification, the alkenyl group content in the organopolysiloxane component can be determined, for example, by analytical methods such as Fourier transform infrared spectroscopy (FT-IR) or nuclear magnetic resonance (NMR), or by the titration method described below.

[0038] This section explains how to quantify the amount of alkenyl groups in each component using titration. The alkenyl group content in organopolysiloxane components can be accurately quantified using 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 equation (1). Next, excess iodine monochloride is reacted with potassium iodide and liberated as iodine via the reaction shown in equation (2). The liberated iodine is then titrated with a sodium thiosulfate solution. Equation (1) CH₂=CH- + 2ICl → CH₂I-CHCl- + ICl (excess) Formula (2) ICl+KI → I2+ KCl The amount of alkenyl groups in the component can be quantified from the difference between the amount of sodium thiosulfate required for titration and the amount of titration of a separately prepared blank solution.

[0039] The aryl group content of the resinous organopolysiloxane of component (A-1) (the mass % of aryl groups relative to the total mass (or molecular weight) of component (A-1)) is more than 0 mass % and not more than 30 mass %. Preferably, the aryl group content of component (A-1) is 5 mass % or more, more preferably 10 mass % or more, and even more preferably 15 mass % or more. Furthermore, the aryl group content of component (A-1) may be 25 mass % or less. Note that, in this specification, the aryl group content in the organopolysiloxane component can be determined, for example, by analysis using a Fourier transform infrared spectrophotometer (FT-IR), nuclear magnetic resonance (NMR), or the like.

[0040] The organopolysiloxane of component (A-1) is preferably solid or semi-solid at 25° C. There are no particular limitations on the mass-average number molecular weight of the organopolysiloxane of component (A-1), but it is preferably within the range of 500 to 10,000. In this specification, the mass-average molecular weight can be measured by GPC.

[0041] The content of component (A-1) is not particularly limited, but may be 5% by mass or more, preferably 10% by mass or more, and more preferably 15% by mass or more, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition. Furthermore, the content of component (A-1) is preferably 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 or the total mass of all organopolysiloxane components in the composition of the present invention. In this specification, "total organopolysiloxane components" refers to all organopolysiloxane components contained in the curable silicone composition of the present invention, specifically including alkenyl group-containing organopolysiloxanes, organohydrogenpolysiloxanes, organopolysiloxanes used as reactive diluents, and organopolysiloxanes containing epoxy group-containing organic groups. Organopolysiloxane components other than these organopolysiloxane components may also be contained.

[0042] In one embodiment, the content of the component (A-1) is 5 to 50% by mass, preferably 10 to 40% by mass, and more preferably 15 to 35% by mass, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition according to the present invention.

[0043] (A-2) is solid at 25°C, contains at least two alkenyl groups per molecule, and is an MQ resin-like alkenyl group-containing organopolysiloxane that does not contain an aryl group

[0044] The MQ resin-like alkenyl group-containing organopolysiloxane of the component (A-2) is solid at 25°C.In this specification, unless otherwise specified, the atmospheric pressure condition is standard atmospheric pressure (atmospheric pressure, 1 atm).

[0045] In a preferred embodiment of the present invention, the MQ resin-like alkenyl group-containing organopolysiloxane of the component (A-2) can preferably be represented by the following average unit formula (II). Average unit formula (II-1): (R 2 3SiO 1 / 2 ) s (SiO 4 / 2 ) t (XO 1 / 2 ) u In the formula, R 2 is the same or different monovalent hydrocarbon group other than a halogen-substituted or unsubstituted aryl group, provided that in one molecule, at least one R 2 is an alkenyl group, 0 < s < 1, 0 < t < 1, 0 ≤ u < 0.4, and s + t = 1. 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.

[0046] R in the above formula (II-1) 2The halogen-substituted or unsubstituted monovalent hydrocarbon group R is a monovalent hydrocarbon group other than an aryl group, and examples thereof include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; alkenyl groups having 2 to 12 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms, such as fluorine, chlorine, or bromine. 2 is preferably selected from alkyl groups having 1 to 6 carbon atoms, particularly a methyl group, and alkenyl groups having 2 to 6 carbon atoms, particularly a vinyl group.

[0047] In the above formula (II-1), X is a hydrogen atom or an alkyl group. The alkyl group for X is preferably an alkyl group having 1 to 3 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, and a propyl group.

[0048] In formula (II-1), s is preferably in the range of 0.2≦s≦0.8, more preferably 0.3≦s≦0.7, and even more preferably 0.4≦s≦0.6. In formula (II-1), t is preferably in the range of 0.2≦t≦0.8, more preferably 0.3≦t≦0.7, and particularly 0.4≦t≦0.6. In formula (II-1), u is preferably in the range of 0≦u≦0.2, more preferably 0≦u≦0.15, and particularly 0≦u≦0.1.

[0049] In another preferred embodiment of the present invention, the MQ resin-like alkenyl-group-containing alkynylpolysiloxane of component (A-2) can be preferably represented by the following average unit formula (II-2): Average unit formula (II-2): (R 3 3SiO 1 / 2 ) s1 (R3 2AkSiO 1 / 2 ) s2 (SiO 4 / 2 ) t (XO 1 / 2 ) u In the formula, R 3 is a monovalent hydrocarbon group other than the same or different halogen-substituted or unsubstituted alkenyl groups and aryl groups, Ak is an alkenyl group, 0 < s1 < 1, 0 < s2 < 1, 0 < t < 1, 0 ≤ u < 0.4 and s1 + s2 + t = 1. 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 taken as 1.

[0050] Among the above formula (II-2), R 3 [[ID=2二十二]]Examples of the monovalent hydrocarbon group other than the halogen-substituted or unsubstituted alkenyl groups and aryl groups include 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; 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. R 3 is preferably selected from alkyl groups having 1 to 6 carbon atoms, particularly the methyl group.

[0051] Examples of the alkenyl group represented by Ak in the above formula (II-2) include alkenyl groups having 2 to 12 carbon atoms such as vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, and preferably the vinyl group.

[0052] In the above formula (II-2), 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 specifically, methyl group, ethyl group, and propyl group are exemplified.

[0053] In formula (II-2), s1 is preferably in the range of 0.2≦s1≦0.7, more preferably 0.3≦s1≦0.6, and even more preferably 0.35≦s1≦0.5. In formula (II-2), s2 is preferably in the range of 0.001≦s2≦0.2, more preferably 0.005≦s2≦0.15, and even more preferably 0.008≦s2≦0.1. In formula (II-2), t is preferably in the range of 0.2≦t≦0.8, more preferably 0.3≦t≦0.7, and particularly 0.4≦t≦0.6. In formula (II-2), u is preferably in the range of 0≦u≦0.2, more preferably 0≦u≦0.15, and particularly 0≦u≦0.1.

[0054] The alkenyl group content of all silicon-bonded organic groups in the MQ resin-like alkenyl-group-containing organopolysiloxane of component (A-2) is not particularly limited, but may be, for example, at least 0.1 mol %, preferably at least 0.3 mol %, and more preferably at least 0.5 mol %, of the total silicon-bonded organic groups, and may be no more than 20 mol %, preferably no more than 15 mol %, and more preferably no more than 10 mol % of the total silicon-bonded organic groups.

[0055] In one embodiment of the present invention, the mass average molecular weight of the MQ resin-like alkenyl group-containing organopolysiloxane of component (A-2) is not particularly limited, but is, for example, within the range of 2,000 to 5,000.

[0056] Furthermore, the proportion (mol %) of Q units relative to the total of M units and Q units in the MQ resin-like alkenyl group-containing organopolysiloxane of component (A-2) is not particularly limited, but is typically 20 to 80%, preferably 30 to 70%, and more preferably 40 to 60%.

[0057] The content of component (A-2) is not particularly limited, but is typically 5% by mass or more, preferably 10% by mass or more, and more preferably 12% by mass or more, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition. Furthermore, the content of component (A-2) is preferably 80% by mass or less, preferably 70% by mass or less, and more preferably 65% ​​by mass or less, based on the total mass of the curable silicone composition.

[0058] In one embodiment, the content of component (A-2) is 5 to 80 mass %, preferably 10 to 70 mass %, and more preferably 15 to 65 mass %, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition.

[0059] (B) At least one organopolysiloxane selected from (B-1) linear organopolysiloxanes containing 7 to 35 siloxane units and containing at least two silicon-bonded hydrogen atoms per molecule or at least two alkenyl groups per molecule at their molecular chain terminals, and (B-2) resinous organohydrogenpolysiloxanes containing at least two silicon-bonded hydrogen atoms per molecule. The curable silicone composition of the present invention comprises, as component (B), an organopolysiloxane selected from (B-1) a linear organopolysiloxane containing 7 to 35 siloxane units and containing at least two silicon-bonded hydrogen atoms per molecule or at least two alkenyl groups per molecule at its molecular chain terminals, and (B-2) a resinous organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule. The curable silicone composition of the present invention may comprise, as component (B), either component (B-1) or component (B-2), or both component (B-1) and component (B-2).

[0060] However, for the purpose of crosslinking the above-mentioned component (A), the organopolysiloxane (B) contains at least one organohydrogenpolysiloxane.

[0061] Component (B-1) is a linear organopolysiloxane containing 7 to 35 siloxane units, and containing at least two silicon-bonded hydrogen atoms per molecule or at least two alkenyl groups per molecule at its molecular chain terminals. That is, component (B-1) is a linear organopolysiloxane containing 7 to 35 siloxane units, and is either (B-1-1) a linear organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule at its molecular chain terminals, or (B-1-2) a linear alkenyl-containing organopolysiloxane containing at least two alkenyl groups per molecule at its molecular chain terminals. The curable silicone composition of the present invention may contain one type of organopolysiloxane (B-1), or two or more types of organopolysiloxanes (B-1).

[0062] (B-1-1) A linear organohydrogenpolysiloxane containing 7 to 35 siloxane units and containing at least two silicon-bonded hydrogen atoms per molecule at its molecular chain terminals does not contain an alkenyl group as an organic group bonded to a silicon atom. (B-1-2) A linear alkenyl-containing organopolysiloxane containing at least two alkenyl groups per molecule at its molecular chain terminals and containing 7 to 35 siloxane units does not contain a silicon-bonded hydrogen atom.

[0063] The organic groups bonded to silicon atoms other than alkenyl groups contained in component (B-1) 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 (B-1) may contain small amounts of hydroxyl groups or alkoxy groups, such as methoxy and ethoxy, as long as the objectives of the present invention are not impaired. The organic group bonded to the silicon atom of component (B-1) other than the alkenyl group is preferably selected from alkyl groups having 1 to 6 carbon atoms, particularly methyl groups.

[0064] The component (B-1) contains 7 to 35 siloxane units. The component (B-1) preferably contains 8 to 30 siloxane units, and more preferably 10 to 25 siloxane units.

[0065] In one embodiment of the present invention, the component (B-1) includes, as the component (B-1-1), a linear organohydrogenpolysiloxane represented by the following average structural formula (III-1): Average structural formula (III-1):R 4 2HSiO(R 4 2SiO 2 / 2 ) n SiHR 4 2 In formula (III-1), R 4 are the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups, and n is 6 to 34.

[0066] R in the above formula (III-1) 4The halogen-substituted or unsubstituted monovalent hydrocarbon group other than an alkenyl group is as described above.

[0067] In the above formula (III-1), n ​​is preferably 7-30, and more preferably 8-25.

[0068] In one embodiment of the present invention, the component (B-1) includes, as component (B-1-2), a linear alkenyl group-containing organopolysiloxane represented by the following average structural formula (III-2): Average structural formula (III-2):AkR 4 2SiO(R 4 2SiO 2 / 2 ) n SiAkR 4 2 In formula (III-2), R 4 are the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups; Ak is an alkenyl group; and n is 6 to 34.

[0069] R in the above formula (III-2) 4 and n are as defined in formula (III-1). Also, Ak in the above formula (III-2) is as defined in the above formula (II-2).

[0070] In one embodiment of the present invention, the organopolysiloxane of component (B-1) is characterized by a low aryl group content. For example, the aryl group content of component (B-1) (the mole percent of aryl groups relative to all silicon-bonded organic groups) can be 10 mole percent or less, preferably 5 mole percent or less, more preferably 3 mole percent or less, even more preferably 1 mole percent or less, and particularly 0.5 mole percent or less. In a preferred embodiment, component (B-1) does not contain any aryl groups.

[0071] When the curable silicone composition of the present invention contains component (B-1), the content of component (B-1) is not particularly limited, but is typically 1% by mass or more, preferably 3% by mass or more, and more preferably 5% by mass or more, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition. Furthermore, the content of component (B-1) is preferably 40% by mass or less, preferably 30% by mass or less, and more preferably 25% by mass or less, based on the total mass of the curable silicone composition.

[0072] In one embodiment, the content of component (B-1) is 1 to 40% by mass, preferably 3 to 30% by mass, and more preferably 5 to 25% by mass, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition.

[0073] Component (B-2) is a resinous organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule. The curable silicone composition of the present invention may contain one type of resinous organohydrogenpolysiloxane as component (B-2), or may contain two or more types of resinous organohydrogenpolysiloxane as component (B-2).

[0074] Examples of organic groups bonded to silicon atoms other than silicon-bonded hydrogen atoms contained in component (B-2) include halogen-substituted or unsubstituted monovalent hydrocarbon groups other than the above-mentioned alkenyl groups, and are preferably selected from alkyl groups having 1 to 6 carbon atoms, particularly methyl groups, and aryl groups having 6 to 20 carbon atoms, particularly phenyl groups.

[0075] (B-2) component's resinous organohydrogenpolysiloxane can be selected from (B-2-1) MT resinous organohydrogenpolysiloxane consisting of only M units and T units, and (B-2-2) MQ resinous organohydrogenpolysiloxane consisting of only M units and Q units. (B-2) component's resinous organohydrogenpolysiloxane may contain either (B-2-1) MT resinous organohydrogenpolysiloxane or (B-2-2) MQ resinous organohydrogenpolysiloxane, or may contain both of them.

[0076] (B-2) component's resinous organohydrogenpolysiloxane may or may not contain D units, but preferably does not contain them. Also, (B-2) component's resinous organohydrogenpolysiloxane preferably contains a silicon atom-bonded hydrogen atom in the M unit.

[0077] (B-2) component contains, as (B-2-1) component, MT resinous organohydrogenpolysiloxane represented by the following average unit formula (IV-1): Average unit formula (IV-1): (R 4 2HSiO 1 / 2 ) s (R 4 SiO 3 / 2 ) t (XO 1 / 2 ) u In formula (IV-1), R 4 is a halogen-substituted or unsubstituted monovalent hydrocarbon group other than the same or different alkenyl groups, 0 < s < 1, 0 < t < 1, 0 ≤ u < 0.4, and s + t = l. 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 taken as 1.

[0078] R in the above formula (IV-1 4 is as defined in formula (III-1). Also, X in the above formula (IV-1) is as defined in formula (I).

[0079] In formula (IV-1), 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 (IV-1), 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 (IV-1), u is preferably in the range of 0 ≦ u ≦ 0.2, more preferably in the range of 0 ≦ u ≦ 0.15, and particularly in the range of 0 ≦ u ≦ 0.1.

[0080] In one embodiment, the component (B-2-1) contains an aryl group in the silicon atom-bonded organic group. The content of the aryl group in the entire silicon atom-bonded group of the MT resin-like organohydrogenpolysiloxane of the component (B-2-1) is not particularly limited, but for example, it is 3 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more of the total of the silicon atom-bonded organic groups, and can be 50 mol% or less, preferably 40 mol% or less, more preferably 30 mol% or less of the total of the silicon atom-bonded groups.

[0081] The component (B-2) contains, as the component (B-2-2), an MQ resin-like organohydrogenpolysiloxane represented by the following average unit formula (IV-2): Average unit formula (IV-2): (R 4 2HSiO 1 / 2 ) s (SiO 4 / 2 ) t (XO 1 / 2 ) u In formula (IV-2), R 4 is the same or different halogen-substituted or unsubstituted monovalent hydrocarbon group other than an alkenyl group, 0 < s < 1, 0 < t < 1, 0 ≦ u < 0.4 and s + t = 1. 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.

[0082] R in the above formula (IV-2) 4is as defined in formula (III-1). X in the above formula (IV-2) is as defined in the above formula (I).

[0083] In formula (IV-2), s is preferably in the range of 0.3≦s≦0.9, more preferably 0.4≦s≦0.8, and even more preferably 0.5≦s≦0.7. In formula (IV-2), t is preferably in the range of 0.1≦t≦0.7, more preferably 0.2≦t≦0.6, and particularly 0.3≦t≦0.5. In formula (IV-2), u is preferably in the range of 0≦u≦0.2, more preferably 0≦u≦0.15, and particularly 0≦u≦0.1.

[0084] In one embodiment of the present invention, the organohydrogenpolysiloxane of component (B-2-2) is characterized by a low aryl group content. For example, the aryl group content of component (B-2-2) (the mole percent of aryl groups relative to all silicon-bonded organic groups) is 10 mole percent or less, preferably 5 mole percent or less, more preferably 3 mole percent or less, even more preferably 1 mole percent or less, and particularly preferably 0.5 mole percent or less. In a preferred embodiment, component (B-2-2) does not contain any aryl groups.

[0085] When the curable silicone composition of the present invention contains component (B-2), the content of component (B-2) is not particularly limited, but is typically 0.5% by mass or more, preferably 1% by mass or more, and more preferably 1.5% by mass or more, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition. Furthermore, the content of component (B-2) is preferably 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.

[0086] In one embodiment, the content of component (B-2) is 0.5 to 20% by mass, preferably 1 to 15% by mass, and more preferably 1.5 to 10% by mass, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition.

[0087] In one embodiment, the total content of component (B) in the curable silicone composition according to the present invention is, based on the total mass of the curable silicone composition according to the present invention or the total mass of all organopolysiloxane components in the composition, 0.5% by mass or more, preferably 1% by mass or more, and more preferably 2% by mass or more, and can be 40% by mass or less, preferably 35% by mass or less, and more preferably 30% by mass or less.

[0088] In one embodiment, the total content of component (B) in the curable silicone composition according to the present invention is 0.5 to 40 mass %, preferably 1 to 35 mass %, and more preferably 2 to 30 mass %, based on the total mass of the curable silicone composition according to the present invention or the total mass of all organopolysiloxane components in the composition.

[0089] (C) Silicone reactive compatibilizer The curable silicone composition of the present invention contains, as component (C), a silicone-reactive compatibilizer, which is an organopolysiloxane having six or fewer siloxane units. The silicone-reactive compatibilizer is selected from (C-1) a linear organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms and at least one aryl group per molecule, (C-2) an MQ resinous organopolysiloxane containing at least two alkenyl groups per molecule, and (C-3) a cyclic organopolysiloxane containing at least two alkenyl groups per molecule. Component (C) may contain any one of components (C-1) to (C-3) alone or in combination.

[0090] The silicone reactive compatibilizer of component (C) typically has two or more siloxane units. Also, the silicone reactive compatibilizer of component (C) is typically liquid at 25°C. In this specification, silicone reactivity specifically refers to hydrosilylation curing reactivity. Such silicone reactive solvents may contain unsaturated bonds, i.e., alkenyl groups, or silicon-bonded hydrogen atoms as reactive groups.

[0091] (C-1) A linear organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms and at least one aryl group per molecule. The curable silicone composition of the present invention may contain (C-1) a linear organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms and at least one aryl group per molecule as a silicone-reactive compatibilizer. The curable silicone composition of the present invention may contain one type of linear organohydrogenpolysiloxane of component (C-1), or may contain two or more types of linear organohydrogenpolysiloxane of component (C-1). Component (C-1) has six or fewer siloxane units, and therefore differs from organopolysiloxane of component (B-1), which has seven or more siloxane units.

[0092] The aryl groups and silicon-bonded organic groups other than aryl groups contained in component (C-1) are as explained above for components (A) and (B).

[0093] The linear organohydrogenpolysiloxane of component (C-1) preferably contains silicon-bonded hydrogen atoms at both ends of the molecular chain.

[0094] In a preferred embodiment of the present invention, the linear organohydrogenpolysiloxane of component (C-1) can be preferably represented by the following average structural formula (V-1). Average structural formula (V-1):R 4 2HSiO(R 4 2SiO 2 / 2 ) n SiHR4 2 In formula (V-1), R 4 are the same or different halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups, and n is 1 to 5.

[0095] R in the above formula (V-1) 4 The halogen-substituted or unsubstituted monovalent hydrocarbon group other than an alkenyl group is as explained above in the components of formulae (III-1) and (B-1).

[0096] In the above formula (V-1), n ​​is preferably 1 to 4, and more preferably 1 to 3.

[0097] In one embodiment, the (C-1) component has an aryl group at a molecular side chain (i.e., D unit). The (C-1) component may or may not contain an aryl group at a molecular end (i.e., M unit), but preferably does not. In another preferred embodiment, the (C-1) component contains at least one (ArSiO 2 / 2 ) structure (wherein Ar represents an aryl group).

[0098] In one embodiment of the present invention, the content of aryl groups in the linear organohydrogenpolysiloxane of component (C-1) is not particularly limited, but may be, for example, 10 mol % or more, preferably 15 mol % or more, and more preferably 20 mol % or more of the total number of silicon-bonded organic groups, and may be 50 mol % or less, preferably 40 mol %, and more preferably 3 mol % or less of the total number of silicon-bonded organic groups.

[0099] When the curable silicone composition of the present invention contains component (C-1), the content of component (C-1) is not particularly limited, but may be, for example, 1% by mass or more, preferably 3% by mass or more, and more preferably 5% by mass or more, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition. Furthermore, the content of component (C-1) is preferably 40% by mass or less, preferably 30% by mass or less, and more preferably 25% by mass or less, based on the total mass of the curable silicone composition or the total mass of all organopolysiloxane components in the composition.

[0100] In one embodiment, the content of component (C-1) is 1 to 40% by mass, preferably 3 to 30% by mass, and more preferably 5 to 25% by mass, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition.

[0101] (C-2) MQ resinous organopolysiloxane containing at least two alkenyl groups per molecule The curable silicone composition according to the present invention may contain, as a silicone-reactive compatibilizer, (C-2) an MQ resinous organopolysiloxane consisting only of M units and Q units and containing at least two alkenyl groups per molecule. The curable silicone composition according to the present invention may contain one type of MQ resinous organopolysiloxane as component (C-2), or it may contain two or more types of MQ resinous organopolysiloxane as component (C-2).

[0102] Component (C-2) is a liquid at 25°C, which differs from the MQ resin-like alkenyl group-containing organopolysiloxane of component (A-2), which is a solid at 25°C.

[0103] The alkenyl groups and silicon-bonded organic groups other than alkenyl groups contained in component (C-2) are as explained above for components (A) and (B).

[0104] In a preferred embodiment of the present invention, the MQ resin-like organopolysiloxane of the component (C-2) can preferably be represented by the following average unit formula (V-2). Average unit formula (V-2): (R 1 3SiO 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, 0 < s < 1, 0 < t < 1, 0 ≤ u < 0.4 and s + t = 1. 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.

[0105] For R 1 and X in the above formula (V-2), the same ones as in the above formula (I) are applicable.

[0106] In the formula (V-2), s is preferably in the range of 0.4 ≤ s ≤ 0.95, more preferably in the range of 0.5 ≤ s ≤ 0.9, and still more preferably in the range of 0.55 ≤ s ≤ 0.85. In the above formula (V-2), t is preferably in the range of 0.05 ≤ t ≤ 0.7, more preferably in the range of 0.1 ≤ t ≤ 0.6, and particularly in the range of 0.15 ≤ t ≤ 0.5. In the above formula (V-2), u is preferably in the range of 0 ≤ u ≤ 0.3, more preferably in the range of 0 ≤ u ≤ 0.2, and particularly in the range of 0 ≤ u ≤ 0.1.

[0107] Also, the ratio (mol%) of the Q unit to the total of the M unit and the Q unit of the MQ resin-like organopolysiloxane of the component (C-2) is not particularly limited, but is preferably 40% or less, and more preferably 30% or less.

[0108] In one embodiment of the present invention, the MQ resinous organopolysiloxane of component (C-2) is characterized by a low aryl group content. For example, the aryl group content of component (C-2) (the mole percent of aryl groups relative to all silicon-bonded functional groups) can be 10 mole percent or less, preferably 5 mole percent or less, more preferably 3 mole percent or less, even more preferably 1 mole percent or less, and particularly 0.5 mole percent or less. In a preferred embodiment, component (C-2) does not contain any aryl groups.

[0109] When the curable silicone composition of the present invention contains component (C-2), the content of component (C-2) is not particularly limited, but may be, for example, 0.3% by mass or more, preferably 0.5% by mass or more, and more preferably 1% by mass or more, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition. Furthermore, the content of component (C-2) is preferably 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 or the total mass of all organopolysiloxane components in the composition.

[0110] In one embodiment, the content of component (C-2) is 0.3 to 20% by mass, preferably 0.5 to 15% by mass, and more preferably 1 to 10% by mass, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition.

[0111] (C-3) A cyclic organopolysiloxane containing at least two alkenyl groups per molecule. The curable silicone composition according to the present invention may contain (C-3) a cyclic organopolysiloxane having at least two alkenyl groups per molecule as a silicone-reactive compatibilizer. The curable silicone composition according to the present invention may contain one type of (C-3) cyclic organopolysiloxane, or two or more types of (C-3) cyclic organopolysiloxanes.

[0112] The alkenyl groups and silicon-bonded organic groups other than alkenyl groups contained in component (C-3) are as explained above for components (A) and (B).

[0113] The cyclic organopolysiloxane of component (C-3) is preferably Average structural formula (V-3): (R 1 2SiO) n (In formula (V-3), 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 n is 4 to 6).

[0114] In the above formula (V-3), R 1 The alkenyl group and halogen-substituted or unsubstituted monovalent hydrocarbon group in formula (I) can be the same as those in formula (I).

[0115] The alkenyl group content of all silicon-bonded organic groups in the cyclic organopolysiloxane of component (C-3) can be designed as desired, but is typically 20 mol% or more, preferably 30 mol% or more, and more preferably 40 mol% or more, and can be 80 mol% or less, preferably 70 mol% or less, and more preferably 60 mol% or less.

[0116] In one embodiment of the present invention, the cyclic organopolysiloxane of component (C-3) is characterized by a low aryl group content. For example, the aryl group content of component (C-3) (the mole percent of aryl groups relative to all silicon-bonded functional groups) can be 10 mole percent or less, preferably 5 mole percent or less, more preferably 3 mole percent or less, even more preferably 1 mole percent or less, and particularly 0.5 mole percent or less. In a preferred embodiment, component (C-3) does not contain any aryl groups.

[0117] When the curable silicone composition according to the present invention contains a cyclic organopolysiloxane (C-3), the content of the component (C-3) is not particularly limited, but is preferably 0.3% by mass or more, preferably 0.5% by mass or more, and more preferably 1% by mass or more, based on the total mass of the curable silicone composition according to the present invention or the total mass of all organopolysiloxane components in the composition. Furthermore, the content of the component (C-3) is 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 or the total mass of all organopolysiloxane components in the composition.

[0118] In one embodiment, the content of component (C-3) is 0.3 to 20% by mass, preferably 0.5 to 15% by mass, and more preferably 1 to 10% by mass, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition.

[0119] In one embodiment, the total content of component (C) in the curable silicone composition according to the present invention is 3% by mass or more, preferably 5% by mass or more, and more preferably 8% by mass or more, and can be 50% by mass or less, preferably 40% by mass or less, and more preferably 35% by mass or less, based on the total mass of the curable silicone composition according to the present invention or the total mass of all organopolysiloxane components in the composition.

[0120] In one embodiment, the total content of component (C) in the curable silicone composition according to the present invention is 3 to 50 mass %, preferably 5 to 40 mass %, and more preferably 8 to 35 mass %, based on the total mass of the curable silicone composition according to the present invention or the total mass of all organopolysiloxane components in the composition.

[0121] In a preferred embodiment, the component (C) includes at least one component (C-1) from the viewpoint of improving the permeability of the cured product.

[0122] When the component (C) of the present invention contains the component (C-1), the content of the component (C-1) is 20% by mass or more and 48% by mass or less, based on the total amount of the components (A-1) and (C-1). Preferably, the content of the component (C-1) is 25% by mass or more and 48% by mass or less, based on the total amount of the components (A-1) and (C-1).

[0123] Furthermore, in a preferred embodiment of the present invention, the combined amount of component (A-2) and component (B-1) is 20% by mass or greater, and more preferably 25% by mass or greater, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition.

[0124] In a preferred embodiment of the present invention, the total content of component (C) is 10% by mass or more relative to the combined content of components (A-2), (B-1), and (C) (i.e., C / (A-2+B-1+C)). In a preferred embodiment of the present invention, the content of component (A-1) is 60% by mass or less relative to the combined content of components (A-1), (A-2), and (B-1) (i.e., A-1 / (A-1+A-2+B-1+C)). This composition of the organopolysiloxane components enables the cured product to have improved crack resistance and high hardness.

[0125] (Other organopolysiloxane components) The curable silicone composition of the present invention may contain other organopolysiloxanes in addition to the above components (A) to (C). Examples of such other organopolysiloxanes include component (A-3), an MQ resin-like alkenyl-containing organopolysiloxane that is liquid at 25°C and contains at least two alkenyl groups per molecule and no aryl groups, and (f) an epoxy-containing organopolysiloxane as an additive.

[0126] Component (A-3) is an MQ resinous organopolysiloxane that is liquid at 25°C and contains at least two alkenyl groups per molecule. The curable silicone composition of the present invention may contain, as component (A-3), an MQ resinous organopolysiloxane consisting solely of M units and Q units, which contains at least two alkenyl groups per molecule and is liquid at 25°C. The curable silicone composition of the present invention may contain one type of MQ resinous organopolysiloxane as component (A-3), or may contain two or more types of MQ resinous organopolysiloxanes as component (A-3). Note that, because component (A-3) is liquid at 25°C, it differs from the MQ resinous alkenyl-group-containing organopolysiloxane of component (A-2), which is solid at 25°C.

[0127] The organic groups bonded to silicon atoms in component (A-3) include alkenyl groups and monovalent hydrocarbon groups other than alkenyl groups, as described above for component (A). The silicon atoms in component (A-3) may contain small amounts of hydroxyl groups or alkoxy groups such as methoxy and ethoxy groups, provided that the objectives of the present invention are not impaired. The organic groups bonded to silicon atoms in component (A-3) are preferably selected from alkyl groups having 1 to 6 carbon atoms, particularly methyl groups, and alkenyl groups having 2 to 12 carbon atoms, particularly vinyl groups. In one embodiment, component (A-4) does not contain an epoxy-containing organic group as an organic group bonded to a silicon atom.

[0128] Component (A-3) does not contain an aryl group as an organic group bonded to a silicon atom, and such an aryl group is as described above for component (A).

[0129] In a preferred embodiment of the present invention, the MQ resinous organopolysiloxane of component (A-3) can be preferably represented by the following average unit formula (VI): Average unit formula (VI-1):(R 2 3SiO 1 / 2 ) s (SiO 4 / 2 ) t (XO 1 / 2 ) u In the formula, R 2is a monovalent hydrocarbon group other than the same or different halogen-substituted or unsubstituted aryl groups, provided that in one molecule, at least two Rs 2 is an alkenyl group, 0 < s < 1, 0 < t < 1, 0 ≦ u < 0.4 and s + t = 1. 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.

[0130] R in the above formula (VI-1) 2 and X are the same as those in the above formula (II-1) and are applicable.

[0131] In formula (VI-1), s is preferably in the range of 0.3 ≦ s ≦ 0.9, more preferably in the range of 0.4 ≦ s ≦ 0.8, and still more preferably in the range of 0.5 ≦ s ≦ 0.7. In the above formula (VI-1), t is preferably in the range of 0.1 ≦ t ≦ 0.6, more preferably in the range of 0.2 ≦ t ≦ 0.5, and particularly in the range of 0.25 ≦ t ≦ 0.4. In the above formula (VI-1), u is preferably in the range of 0 ≦ u ≦ 0.3, more preferably in the range of 0 ≦ u ≦ 0.2, and particularly in the range of 0 ≦ u ≦ 0.1.

[0132] [[ID=I6]]The content of the alkenyl group in the whole of the silicon atom-bonded organic groups of the MQ resin-like alkenyl group-containing organopolysiloxane of the component (A-3) is not particularly limited, but for example, it is 0.1 mol% or more, preferably 0.3 mol% or more, more preferably 0.5 mol% or more of the total of the silicon atom-bonded organic groups, and can be 20 mol% or less, preferably 15 mol% or less, more preferably 10 mol% or less of the total of the silicon atom-bonded organic groups.

[0133] The mass average molecular weight of the MQ resin-like organopolysiloxane of component (A-3) is not particularly limited, but is, for example, in the range of 300 or more and less than 2,000. In this specification, the mass average molecular weight can be measured by GPC. Typically, an MQ resin-like organopolysiloxane with a mass average molecular weight of less than about 2,000 can be liquid at 25°C. In a preferred embodiment, the mass average molecular weight of the MQ resin-like organopolysiloxane of component (A-3) is in the range of 500 to 1,800.

[0134] Furthermore, the proportion of Q units relative to the total of M and Q units in the MQ resinous organopolysiloxane of component (A-3) is not particularly limited, but is preferably 40% or less. In general, the smaller the proportion of Q units in the molecule, the more likely it is to be a liquid at 25°C.

[0135] When the curable silicone composition of the present invention contains component (A-3), its content is not particularly limited, but is typically 1% by mass or more, preferably 2% by mass or more, and more preferably 3% by mass or more, based on the total mass of the hot-melt curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition. Furthermore, the content of component (A-3) is preferably 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.

[0136] In one embodiment, the content of component (A-3) is typically 1 to 20% by mass, preferably 2 to 15% by mass, and more preferably 3 to 10% by mass, based on the total mass of the curable silicone composition of the present invention or the total mass of all organopolysiloxane components in the composition.

[0137] (f) Epoxy-containing organopolysiloxane may be a preferred tackifier. The epoxy-containing organopolysiloxane differs from the above components (A) to (C) in that it contains an epoxy-containing organic group at least among the silicon-bonded organic groups.

[0138] The molecular structure of the epoxy group-containing organopolysiloxane can be exemplified by linear, partially branched linear, branched, resinous, cyclic, and three-dimensional network structures, with resinous epoxy group-containing organopolysiloxanes being preferred. The curable silicone composition according to the present invention may contain one type of epoxy group-containing organopolysiloxane, or may contain a combination of two or more types of epoxy group-containing organopolysiloxanes.

[0139] The epoxy group-containing organopolysiloxane preferably contains, as the alkenyl group, an alkenyl group having 2 to 12 carbon atoms, such as a vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, or dodecenyl group, preferably a vinyl group. Furthermore, examples of the epoxy group-containing organic group include glycidoxyalkyl groups such as a 2-glycidoxyethyl group, a 3-glycidoxypropyl group, and a 4-glycidoxybutyl group; epoxycycloalkylalkyl groups such as a 2-(3,4-epoxycyclohexyl)-ethyl group and a 3-(3,4-epoxycyclohexyl)-propyl group; and epoxyalkyl groups such as a 3,4-epoxybutyl group and a 7,8-epoxyoctyl group, with a glycidoxyalkyl group being preferred, and a 3-glycidoxypropyl group being particularly preferred.

[0140] Examples of groups bonded to silicon atoms other than alkenyl groups and epoxy-containing organic groups in epoxy-containing organopolysiloxanes include halogen-substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups and epoxy-containing organic groups. Examples include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, phenethyl, and phenylpropyl; 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. Preferred are alkyl groups having 1 to 12 carbon atoms, and particularly methyl groups.

[0141] The resinous epoxy group-containing organopolysiloxane can preferably be represented by the following average unit formula (VI-2): Average unit formula (VI-2):(R 5 3SiO 1 / 2 ) f (R 5 2SiO 2 / 2 ) g (R 5 SiO 3 / 2 ) h (SiO 4 / 2 ) i (XO 1 / 2 ) j {In formula (VI-2), R 5 are each independently a halogen-substituted or unsubstituted monovalent hydrocarbon group, provided that at least two R 5 is an alkenyl group, and at least one R 5 is an epoxy group-containing organic group, X is a hydrogen atom or an alkyl group, 0≦f<1, 0≦g<1, 0≦h<0.9, 0≦i<0.5, and 0≦j<0.4, and f+g+h+i+j=1.0, h+i>0}.

[0142] In the above formula (VI-2), R5 Examples of the halogen-substituted or unsubstituted monovalent hydrocarbon group include the above-mentioned alkenyl groups, epoxy group-containing organic groups, and other monovalent hydrocarbon groups. Furthermore, X in formula (VI-2) is a hydrogen atom or an alkyl group. The alkyl group represented by 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.

[0143] In the formula (VI-2), f is preferably in the range of 0.05≦f≦0.5, more preferably in the range of 0.05≦f≦0.4, and even more preferably in the range of 0.1≦f≦0.3. In the formula (VI-2), g is preferably in the range of 0.1≦g≦0.6, more preferably in the range of 0.15≦g≦0.5, and particularly in the range of 0.2≦g≦0.4. In the formula (VI-2), h is preferably in the range of 0.2≦h≦0.8, more preferably in the range of 0.3≦h≦0.7, and particularly in the range of 0.4≦h≦0.6. In the formula (VI-2), i is preferably in the range of 0≦i≦0.4, more preferably in the range of 0≦i≦0.25, and particularly in the range of 0≦i≦0.1. In the above formula (VI-2), j is preferably in the range of 0.05≦j≦0.5, more preferably in the range of 0.1≦j≦0.4, and particularly preferably in the range of 0.15≦j≦0.3.

[0144] In a preferred embodiment of the present invention, the resinous epoxy-containing organopolysiloxane has formula (VI-2) in which h is greater than 0, i.e., it contains T units. The epoxy-containing resinous organopolysiloxane may or may not contain Q units, but preferably does not contain them.

[0145] In a preferred embodiment of the present invention, the epoxy group-containing organopolysiloxane has an epoxy group-containing organic group as a pendant group on a molecular side chain, and the epoxy group-containing organopolysiloxane preferably has the epoxy group-containing organic group in the D unit.

[0146] The amount of epoxy-containing organic groups in the epoxy-containing organopolysiloxane relative to all silicon-bonded organic groups is not particularly limited, but is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, and is, for example, 40 mol% or less, 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.

[0147] The number average molecular weight of the epoxy group-containing organopolysiloxane is not particularly limited, but can be within the range of 1,000 to 10,000.

[0148] The content of the epoxy group-containing organopolysiloxane is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more, based on the total mass of the hot-melt curable silicone composition of the present invention; and may be 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 hot-melt curable silicone composition of the present invention.

[0149] From the viewpoint of component compatibility, the curable silicone composition according to the present invention is characterized by a low content of resinous alkenyl-group-containing organopolysiloxanes having at least two alkenyl groups and at least one aryl group per molecule, the content of which is greater than 30% by mass. Specifically, the content of resinous alkenyl-group-containing organopolysiloxanes having at least two alkenyl groups and at least one aryl group per molecule, the content of which is greater than 30% by mass, is 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, preferentially 3% by mass or less, and particularly preferably 1% by mass or less, based on the total mass of the curable silicone composition or the total mass of all organopolysiloxane components in the composition. Furthermore, in a particularly preferred embodiment of the present invention, the curable silicone composition according to the present invention is a resinous alkenyl group-containing organopolysiloxane having at least two alkenyl groups and at least one aryl group per molecule, but does not contain a resinous alkenyl group-containing organopolysiloxane containing aryl groups in an amount greater than 30% by mass.

[0150] From the viewpoint of component compatibility, the curable silicone composition according to the present invention is characterized by a low content of linear organopolysiloxanes containing more than 35 siloxane units. Specifically, the content of linear organopolysiloxanes containing more than 35 siloxane units is 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, preferentially 3% by mass or less, and particularly preferably 1% by mass or less, based on the total mass of the curable silicone composition or the total mass of all organopolysiloxane components in the composition. Furthermore, in a particularly preferred embodiment of the present invention, the curable silicone composition according to the present invention does not contain linear organopolysiloxanes containing more than 35 siloxane units.

[0151] Furthermore, the curable silicone composition of the present invention can contain an alkenyl group-containing organopolysiloxane with a linear, branched, resinous, and / or three-dimensional network structure, as long as the effects of the present invention are not impaired.

[0152] In a preferred embodiment of the present invention, the ratio of silicon-bonded alkenyl groups to silicon-bonded hydrogen atoms (H / Ak) contained in all organopolysiloxane components of the curable silicone composition is less than 1.2 moles, preferably less than 1.1 moles, of silicon-bonded hydrogen atoms per mole of silicon-bonded alkenyl groups, and is typically at least 0.50 moles, preferably at least 0.60 moles, and more preferably at least 0.70 moles.

[0153] (D) Curing catalyst The curing catalyst of component (D) is a hydrosilylation reaction curing catalyst that accelerates 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, platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complexes, and platinum-supported powders; palladium-based catalysts such as tetrakis(triphenylphosphine)palladium, palladium black, and mixtures with triphenylphosphine; and rhodium-based catalysts, with platinum-based catalysts being particularly preferred.

[0154] The amount of component (D) blended is a catalytic amount. More specifically, when a platinum 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. Furthermore, the amount of platinum atoms, relative to the total mass of the curable silicone composition of the present invention, is preferably no more than 50 ppm, more preferably no more than 40 ppm, and even more preferably no more than 35 ppm.

[0155] (E) Reaction inhibitor The reaction inhibitor (E) is a hydrosilylation reaction inhibitor that inhibits the hydrosilylation reaction of the organopolysiloxane component of the present invention. Examples of such curing reaction inhibitors include alkyne alcohols 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-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; tetramethyltetravinylcyclotetrasiloxane and tetramethyltetrahexenylcyclotetrasiloxane; and the like. Examples of suitable hydrosilylation reaction inhibitors include alkenyl-containing low-molecular-weight siloxanes; 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; maleic acid esters such as diallyl maleate and bis(2-ethylhexyl) maleate; and disulfide compounds having a disulfide structure such as di-dodecyl disulfide, di-decyl disulfide, and di-octyl disulfide. The hydrosilylation reaction inhibitor is preferably selected from alkyne alcohols and maleic acid esters, and particularly preferably contains an alkyne alcohol and a maleic acid ester. The amount of the reaction inhibitor added is typically 0.001 to 5% by mass of the total composition.

[0156] (Other ingredients) The curable silicone composition of the present invention can contain optional components as long as they do not impair the object of the present invention. Examples of optional components include acetylene compounds, organic phosphorus compounds, vinyl group-containing siloxane compounds, inorganic fillers such as ground quartz, silica, magnesium carbonate, and diatomaceous earth, inorganic fillers obtained by hydrophobizing the surface of such inorganic fillers with organic silicon compounds, surface treatment agents, tackifiers, heat resistance agents, cold resistance agents, flame retardants, thixotropy agents, and fluorescent materials. The amount of these optional components added is typically 0.001 to 20% by mass of the total composition.

[0157] The curable silicone composition of the present invention can be cured to form a cured product with good transparency. Specifically, the cured product of the curable silicone composition of the present invention preferably has a light transmittance of more than 80% at wavelengths of 400 nm to 700 nm. The light transmittance of the cured product of the curable silicone composition can be determined, for example, by measuring the cured product with an optical path length of 1 using a spectrophotometer.

[0158] The curable silicone composition of the present invention can be cured to form a cured product with high hardness. Preferably, the cured product obtained by curing the curable silicone composition of the present invention has a Type D durometer hardness of greater than D30 at 25°C. This Type D durometer hardness is determined using a Type D durometer in accordance with JIS K 6253-1997 "Testing method for hardness of vulcanized rubber and thermoplastic rubber."

[0159] The curable silicone composition of the present invention can be prepared by mixing the various components. The method for mixing the various components can be any conventionally known method, and is not particularly limited. For example, the composition can be prepared by mixing using a mixing device. There are no particular limitations on such mixing devices, and examples include single- or double-screw continuous mixers, twin-roll mixers, Ross mixers, Hobart mixers, dental mixers, planetary mixers, kneader mixers, and Henschel mixers.

[0160] [Sealants, adhesives] The present invention also relates to an encapsulant or adhesive for semiconductors that uses the curable silicone composition of the present invention. The shape of the encapsulant or adhesive of the present invention is not particularly limited, but is preferably in the form of a film or sheet, and can be provided as an encapsulant film or laminate film for semiconductor encapsulation. The semiconductors that can be encapsulated with the encapsulant of the present invention are not particularly limited, and examples include semiconductors such as SiC and GaN, particularly power semiconductors or optical semiconductors such as light-emitting diodes.

[0161] [Optical semiconductor element] The present invention also relates to an optical semiconductor element comprising the encapsulant of the present invention. Examples of optical semiconductor elements include light-emitting diodes (LEDs), semiconductor lasers, photodiodes, phototransistors, solid-state imaging devices, and light emitters and photodetectors for photocouplers, with light-emitting diodes (LEDs) being particularly preferred.

[0162] Light-emitting diodes (LEDs) emit light from the top, bottom, left, and right of the optical semiconductor element. Therefore, light-absorbing materials are not preferred for the components that make up the LED; rather, materials with high light transmittance or high reflectance are preferred. Therefore, the substrate on which the optical semiconductor element is mounted is also preferably made of a material 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 containing white pigments, such as PPA and LCP; thermosetting resins containing white pigments, such as epoxy resin, BT resin, polyimide resin, and silicone resin; and ceramics, such as alumina and alumina nitride.

[0163] Specific embodiments of the present invention will be described below. Aspect 1: (A) A resinous alkenyl group-containing organopolysiloxane comprising the following (A-1) and (A-2): (A-1) A resinous alkenyl-containing organopolysiloxane containing at least two alkenyl groups and at least one aryl group per molecule. (A-2) an MQ resin-like alkenyl group-containing organopolysiloxane that is solid at 25°C and contains at least two alkenyl groups per molecule and does not contain any aryl groups; (B) At least one organopolysiloxane selected from the following (B-1) and (B-2): (B-1) A linear organopolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule or at least two alkenyl groups per molecule at its molecular chain terminals, and containing 7 to 35 siloxane units. (B-2) a resinous organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule; (C) a silicone reactive compatibilizer which is an organopolysiloxane having 6 or less siloxane units selected from (C-1) a linear organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms and at least one aryl group per molecule, (C-2) an MQ resinous organopolysiloxane containing at least two alkenyl groups per molecule, and (C-3) a cyclic organopolysiloxane containing at least two alkenyl groups per molecule; (D) a curing catalyst; and (E) Reaction inhibitor 1. A curable silicone composition comprising: the content of aryl groups in the component (A-1) is more than 0% by mass and 30% by mass or less, relative to the total mass of the component (A-1); (B) the organopolysiloxane comprises at least one organohydrogenpolysiloxane; when the component (C) contains the component (C-1), the content of the component (C-1) is 20% by mass or more and 48% by mass or less based on the total amount of the component (A-1) and the component (C-1); a resinous alkenyl group-containing organopolysiloxane having at least two alkenyl groups and at least one aryl group per molecule, wherein the content of the resinous alkenyl group-containing organopolysiloxane containing aryl groups in an amount greater than 30% by weight is 15% by weight or less based on the total weight of the curable silicone composition; A curable silicone composition having a linear organopolysiloxane content of more than 35 siloxane units of 15% by weight or less, based on the total weight of the curable silicone composition. Aspect 2: The curable silicone composition according to Aspect 1, wherein the content of component (A-1) is 5 to 50 mass % based on the total mass of the curable silicone composition of the present invention. Aspect 3: The curable silicone composition of Aspect 1 or 2, comprising component (C-1). Aspect 4: The curable silicone composition according to any one of Aspects 1 to 3, wherein the total content of component (C) is 3 to 50 mass % based on the total mass of the curable silicone composition. Aspect 5: The curable silicone composition according to any one of Aspects 1 to 4, wherein the combined amount of component (A-2) and component (B-1) is 20 mass % or greater, based on the total mass of the curable silicone composition of the present invention. Aspect 6: The curable silicone composition according to any one of Aspects 1 to 5, wherein the total amount of component (C) is 10 mass% or greater, based on the combined amount of component (A-2), component (B-1), and component (C). Aspect 7: The curable silicone composition according to any one of Aspects 1 to 6, wherein the amount of component (A-1) is 60 mass% or less, based on the combined amount of components (A-1), (A-2), and (B-1). Aspect 8: A sealant or adhesive comprising the curable silicone composition according to any one of Aspects 1 to 7. Embodiment 9: An optical semiconductor device encapsulated with the encapsulant of embodiment 8. [Example]

[0164] The curable silicone composition of the present invention will be described in more detail below with reference to the following examples and comparative examples.

[0165] Curable silicone compositions were prepared by mixing the components in the amounts (parts by mass) shown in the table. Hereinafter, Me represents a methyl group, Vi represents a vinyl group, and Ph represents a phenyl group. The structures of the organopolysiloxane components are shown in simplified form in the table, with the organic groups other than Me in the M, D, T, or Q units indicated in parentheses. The H / Vi ratio indicates the molar ratio of silicon-bonded hydrogen atoms (H) to vinyl groups (Vi) in the organopolysiloxane component. The "total aryl group content" indicates the amount (mol %) of aryl groups in all silicon-bonded organic groups in the entire organopolysiloxane component.

[0166] Component a-1: Average unit formula (Me3SiO 1 / 2 ) 14 (Me2ViSiO1 / 2 ) 11 (MeSiO 3 / 2 ) 53 (PhSiO 3 / 2 ) 22 Resin-like alkenyl group-containing organopolysiloxane (aryl group content: 20% by mass, mass average molecular weight: 6000 Component a'-1-1: (Me3SiO 1 / 2 )5(Me2ViSiO 1 / 2 ) 17 (MeSiO 3 / 2 ) 39 (PhSiO 3 / 2 ) 39 Resin-like alkenyl group-containing organopolysiloxane (aryl group content: 31% by mass, mass average molecular weight: 2500) Component a'-1-2: (Me 32 ViSiO 1 / 2 ) 15 (MeSiO 2 / 2 ) 35 (PhSiO 3 / 2 ) 50 Resin-like alkenyl group-containing organopolysiloxane (aryl group content: 37% by mass, mass average molecular weight: 2000) Component a-2-1: Average unit formula (Me3SiO 1 / 2 ) 46 (Me2ViSiO 1 / 2 )5(SiO 4 / 2 ) 49 Alkenyl group-containing MQ resin represented by (OH)6, solid at 25°C, molecular weight 2800 Component a-2-2: Average unit formula (Me3SiO 1 / 2 ) 41 (Me2ViSiO 1 / 2 )7(SiO 4 / 2 ) 52 Alkenyl group-containing MQ resin represented by (OH)5, solid at 25°C, molecular weight 2800 Component a-2-3: Average unit formula (Me3SiO 1 / 2 ) 45.6 (Me2ViSiO 1 / 2 ) 2.9 (SiO 4 / 2 ) 51.5 (OH)3.5 Alkenyl group-containing MQ resin that is solid at 25°C. Molecular weight: 3300 Component a-2-4: Average unit formula (Me3SiO 1 / 2 ) 47.9 (Me2ViSiO 1 / 2 ) 0.9 (SiO 4 / 2 ) 51.2 (OH) 4.3 Alkenyl group-containing MQ resin that is solid at 25°C. Molecular weight: 3300 Component a-3-1: Average unit formula (Me3SiO 1 / 2 ) 45 (Me2ViSiO 1 / 2 ) 15 (SiO 4 / 2 ) 40 Alkenyl group-containing MQ resin that is liquid at 25°C. Molecular weight: 1000 Component a-3-2: Average unit formula (Me3SiO 1 / 2 ) 25 (Me2ViSiO 1 / 2 ) 37 (SiO 4 / 2 ) 38 Alkenyl group-containing MQ resin represented by (OH)4, liquid at 25°C. Molecular weight: 1500 Component b-1-1: Average structural formula HMe2SiO(Me2SiO) 20 Linear organohydrogenpolysiloxane represented by SiHMe2 Component b-1-2: Average structural formula ViMe2SiO(Me2SiO) 10.3 Linear alkenyl group-containing organopolysiloxane represented by SiViMe2 Component b'-1-1: Average structural formula HMe2SiO(Me2SiO) 50 Linear organohydrogenpolysiloxane represented by SiHMe2 Component b'-1-2: Average structural formula ViMe2SiO(Me2SiO) 40 Linear alkenyl group-containing organopolysiloxane represented by SiViMe2 Component b-2-1: (HMe2SiO 1 / 2 ) 60 (PhSiO3 / 2 ) 40 MT resin-type organohydrogenpolysiloxane, represented by the formula: Molecular weight: 750 Component b-2-2: (HMe2SiO 1 / 2 ) 62 (SiO 4 / 2 ) 38 MQ resin-type organohydrogenpolysiloxane represented by the formula Molecular weight: 1600 Component c-1: A reactive compatibilizer that is a linear organohydrogenpolysiloxane with the average structural formula HMe2SiO(Ph2SiO)SiHMe2 Component c-2: Average structural formula (ViMe2SiO 1 / 2 )4(SiO 4 / 2 ) is a reactive compatibilizer that is an MQ resinous organopolysiloxane. Component c-3: A reactive compatibilizer that is a cyclic alkenyl group-containing organopolysiloxane represented by the average structural formula (ViMeSiO)4 Component d: A complex of platinum and divinyltetramethyldisiloxane with a platinum concentration of 3.0% by mass Component e: 1-ethynyl-1-cyclohexanol Component f: Average unit formula (ViMe2SiO 1 / 2 ) 13 (EpMeSiO 2 / 2 ) 24 (PhSiO 3 / 2 ) 46 (OMe) 17 A resin-like epoxy group-containing organopolysiloxane as an additive, represented by the formula: Component g: Fumed silica (surface treated with hexamethyldisilazane and trimethylsilane)

[0167] [evaluation] The following evaluation tests were carried out. However, for Comparative Examples 5 to 10, 13, 14, 16 to 18, and 20, the components were not compatible and a uniform curable silicone composition was not obtained, so the following evaluation tests were not carried out.

[0168] (light transmittance) The resulting curable silicone composition was placed between two transparent glass plates and cured by heating at 150°C for 1 hour to prepare a test specimen with an optical path length of 1 mm. The light transmittance of this test specimen was measured at 25°C using a recording spectrophotometer capable of measuring any wavelength in the visible light range (wavelengths of 400 nm to 700 nm). Test specimens with a light transmittance of over 80% were rated as OK, and those with a light transmittance of 80% or less were rated as NG.

[0169] (Hardness of cured product) The resulting curable silicone composition was cured at 150°C for 1 hour, and a 10 mm thick test specimen was prepared. The hardness at 25°C was measured using a Durometer D hardness tester. Tests with a hardness exceeding D30 were rated as OK, and those with a hardness of D30 or less were rated as NG.

[0170] (Die shear strength) A 25mm x 75mm alumina plate was used as the substrate, and five 5mm x 5mm x 1mm alumina chips were used as bonding chips. 0.0080g ± 0.0005g of curable silicone composition was applied to each chip, and the chip was placed on the composition. The composition was then cured at 150°C for 2 hours to bond each chip to the substrate. Die shear strength was measured using a bond tester (model number: SS-30WD, test mode: PH50 push, speed: 0.120mm / sec). Die shear strengths exceeding 500kPa were considered acceptable, while those below 500kPa were considered unacceptable.

[0171] (Presence or absence of cracks after heat treatment) The resulting curable silicone composition was cured at 150°C for 1 hour to prepare a 10mm thick test specimen, which was then cycled 1000 times between 40°C and 125°C before being visually inspected for cracks in the cured product. Each cycle consisted of holding the specimen at 40°C and 125°C for 30 minutes each. Test specimens in which no cracks were observed were rated as "OK," and those in which cracks were observed were rated as "NG."

[0172] The results are shown in the table below.

[0173] [Table 1]

[0174] [Table 2]

[0175] [Table 3]

[0176] [Table 4]

[0177] [Table 5]

[0178] As can be seen from the above results, the curable silicone compositions of the examples of the present invention were able to form cured products that had excellent transparency, high hardness and strength, and improved resistance to cracking due to temperature changes. [Industrial Applicability]

[0179] The curable silicone composition of the present invention is useful as a sealant, coating agent, or adhesive for optical semiconductor elements such as light-emitting diodes (LEDs), semiconductor lasers, photodiodes, phototransistors, solid-state imaging devices, and light emitters and photoreceptors for photocouplers.

Claims

1. (A) A resinous alkenyl group-containing organopolysiloxane containing the following (A-1) and (A-2): (A-1) A resinous alkenyl-containing organopolysiloxane containing at least two alkenyl groups and at least one aryl group per molecule. (A-2) an MQ resin-like alkenyl group-containing organopolysiloxane that is solid at 25°C and contains at least two alkenyl groups per molecule and does not contain any aryl groups; (B) At least one organopolysiloxane selected from the following (B-1) and (B-2): (B-1) A linear organopolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule or at least two alkenyl groups per molecule at its molecular chain terminals, and containing 7 to 35 siloxane units. (B-2) a resinous organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule; (C) a silicone-reactive compatibilizer which is an organopolysiloxane having 6 or fewer siloxane units selected from (C-1) a linear organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms and at least one aryl group per molecule, (C-2) an MQ resinous organopolysiloxane containing at least two alkenyl groups per molecule, and (C-3) a cyclic organopolysiloxane containing at least two alkenyl groups per molecule; (D) a curing catalyst; and (E) Reaction inhibitor 1. A curable silicone composition comprising: the content of aryl groups in the component (A-1) is more than 0% by mass and 30% by mass or less, relative to the total mass of the component (A-1); (B) the organopolysiloxane comprises at least one organohydrogenpolysiloxane; when the component (C) contains the component (C-1), the content of the component (C-1) is 20% by mass or more and 48% by mass or less based on the total amount of the component (A-1) and the component (C-1); a resinous alkenyl group-containing organopolysiloxane having at least two alkenyl groups and at least one aryl group per molecule, wherein the content of the resinous alkenyl group-containing organopolysiloxane containing aryl groups in an amount greater than 30% by weight is 15% by weight or less based on the total weight of the curable silicone composition; A curable silicone composition having a linear organopolysiloxane content of more than 35 siloxane units of 15% by weight or less, based on the total weight of the curable silicone composition.

2. 2. The curable silicone composition according to claim 1, wherein the content of component (A-1) is 5 to 50 mass % based on the total mass of the curable silicone composition of the present invention.

3. 3. The curable silicone composition according to claim 1, further comprising a component (C-1).

4. 2. The curable silicone composition according to claim 1, wherein the total content of component (C) is 3 to 50 mass % based on the total mass of the curable silicone composition.

5. 2. The curable silicone composition according to claim 1, wherein the combined amount of component (A-2) and component (B-1) is 20% by mass or more, based on the total mass of the curable silicone composition of the present invention.

6. 2. The curable silicone composition according to claim 1, wherein the total amount of component (C) is 10 mass% or more relative to the combined amount of components (A-2), (B-1), and (C).

7. 2. The curable silicone composition according to claim 1, wherein the amount of component (A-1) is 60 mass % or less based on the total amount of components (A-1), (A-2), and (B-1).

8. 8. A sealant or adhesive comprising the curable silicone composition according to claim 1.

9. 9. An optical semiconductor device encapsulated with the encapsulant according to claim 8.

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