Thermal Conductive Silicon Composition

Abstract

To provide a thermally conductive silicone composition having excellent electrical insulation, dischargeability, and heat dissipation properties, and having a low BLT.SOLUTION: A thermally conductive silicone composition comprises: (A) a polyorganosiloxane having an alkenyl group bonded to a silicon atom, (B) a polyorganohydrogensiloxane having a hydrogen atom bonded to a silicon atom, (C) a platinum catalyst, (D) a siloxane compound represented by general formula (1), and (E) a thermally conductive filler, wherein the total content of components (A) to (D) is 1.0 to 10 pts.mass per 100 pts.mass of component (E).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermally conductive silicone composition.

Background Art

[0002] Recently, with the high performance and miniaturization of electronic components represented by power modules and CPUs, thermal management has been demanded. For this thermal management, thermally conductive greases and heat dissipation sheets are used. Thermally conductive greases have problems such as so-called pumping out, in which the thermally conductive grease is extruded from the coating part due to the thermal expansion and contraction of the heat generating element and the heat exchange part, and the problem that the filler and the oil are separated over time. Therefore, in terms of reliability and functionality, it is still in the process of development. On the other hand, although the heat dissipation sheet is a molded product and does not have the above problems, there are concerns about heat dissipation from the viewpoint of thermal resistance and contact resistance caused by the increase in the thickness of the heat dissipation sheet itself.

[0003] In order to solve this problem, in a composition containing a thermally conductive filler and silicone, a technique of using a large particle size inorganic filler or a plurality of types of inorganic fillers to increase the thermal conductivity has been proposed. For example, Patent Document 1 discloses a thermally conductive polysiloxane composition using silicon carbide having at least two peaks in the particle size distribution.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a heat dissipating material, considering the thermal resistance, thin coating is an important factor. As an index of how thin it can be coated, there is BLT (Bond-Line-Thickness). The thickness of the heat dissipating material greatly affects the heat dissipation performance, and since reducing the thickness contributes to reducing the thermal resistance, the BLT characteristic becomes important for high heat dissipation materials.

[0006] Also, according to the findings of the inventors, in the thermally conductive polysiloxane composition as described in Patent Document 1, it was found that there is room for improvement in terms of electrical insulation characteristics, BLT characteristics, dischargeability, and heat dissipation performance.

[0007] An object of the present invention is to provide a thermally conductive silicone composition that is excellent in electrical insulation, dischargeability, and heat dissipation performance and has a low BLT.

Means for Solving the Problems

[0008] The present invention relates to the following [1] to [6]. [1] (A) A polyorganosiloxane having an alkenyl group bonded to a silicon atom; (B) A polyorganohydrogensiloxane having a hydrogen atom bonded to a silicon atom; (C) A platinum-based catalyst; (D) The following general formula (1):

Chemical formula

Chemical formula

Advantages of the Invention

[0009] According to the present invention, there is provided a thermally conductive silicone composition having excellent electrical insulation, dischargeability, and heat dissipation properties, and a low BLT.

Embodiments for Carrying Out the Invention

[0010] [Definition of Terms] The structural units of siloxane compounds may be described by the following abbreviations (hereinafter, these structural units may be referred to as "M units", "D H units", etc.). M : Si(CH3)3O 1 / 2 M H : SiH(CH3)2O 1 / 2 M Vi : (CH=CH2)(CH3)2SiO 1 / 2 D : Si(CH3)2O 2 / 2 D H : SiH(CH3)O 2 / 2

[0011] In this specification, specific examples of groups are as follows. Examples of monovalent hydrocarbon groups include alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, and alkenyl groups. Examples of monovalent hydrocarbon groups having no aliphatic unsaturated bond include the above monovalent hydrocarbon groups other than alkenyl groups. An alkenyl group is a linear or branched group having 2 to 6 carbon atoms, and examples thereof include a vinyl group, an allyl group, a 3-butenyl group, and a 5-hexenyl group. An alkyl group is a linear or branched group having 1 to 18 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, a dodecyl group, a hexadecyl group, and an octadecyl group. A cycloalkyl group is a monocyclic or polycyclic group having 3 to 20 carbon atoms, and examples thereof include a cyclopentyl group and a cyclohexyl group. An aryl group is an aromatic group containing a monocyclic or polycyclic group having 6 to 20 carbon atoms, and examples thereof include a phenyl group and a naphthyl group. An aralkyl group is an alkyl group substituted with an aryl group, and examples thereof include a 2-phenylethyl group and a 2-phenylpropyl group. The alkylene group is a linear or branched group having 1 to 18 carbon atoms, and examples thereof include a methylene group, an ethylene group, a trimethylene group, a 2-methylethylene group, and a tetramethylene group. The alkenyl group, alkyl group, cycloalkyl group, aryl group, aralkyl group, and alkylene group may be substituted with a halogen such as chlorine, fluorine, or bromine; a cyano group; or the like. Examples of the group substituted with a halogen include a chloromethyl group, a chlorophenyl group, and a 3,3,3-trifluoropropyl group, and examples of the group substituted with a cyano group include a 2-cyanoethyl group.

[0012] In this specification, the "polyorganosiloxane having an alkenyl group bonded to a silicon atom" (A) is also referred to as the "(A) component". The same applies to the "(C) platinum-based catalyst" and the like.

[0013] [Thermally Conductive Silicon Composition] The thermally conductive silicon composition (hereinafter also simply referred to as the "composition") is as follows: (A) A polyorganosiloxane having an alkenyl group bonded to a silicon atom; (B) A polyorganohydrogensiloxane having a hydrogen atom bonded to a silicon atom; (C) A platinum-based catalyst; (D) The following general formula (1): [Chemical formula] [In the formula, R 1 : A group having an alkoxysilyl group having 1 to 4 carbon atoms R 2 : The following general formula (2): [Chemical formula] (In the formula, R 4 are each independently a monovalent hydrocarbon group having 1 to 12 carbon atoms, Y is a group selected from the group consisting of R 4 and an aliphatic unsaturated group, and d is an integer of 2 to 60) and represents a linear organosiloxy group X: Each independently a divalent hydrocarbon group having 2 to 10 carbon atoms a and b: Each independently an integer of 1 or more c: An integer of 0 or more a + b + c: An integer of 4 or more R 3 : Each independently a monovalent hydrocarbon group having 1 to 6 carbon atoms or a hydrogen atom The siloxane compound represented by, and (E) A thermal conductivity filler, A thermally conductive silicone composition containing (A) component contains a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in the molecule, (B) component contains a polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms in the molecule, (E) component is (E-1) Silicon carbide having a peak in the particle size distribution in the range of 10 μm or more and 40 μm or less, (E-2) A first thermal conductivity filler having a thermal conductivity of 10 W / mK to 300 W / mK and a peak in the particle size distribution in the range of 0.1 μm or more and 1.0 μm or less, (E-3) A second thermal conductivity filler having a thermal conductivity of 10 W / mK to 300 W / mK and a peak in the particle size distribution in the range of more than 1.0 μm and less than 10 μm, and (E-4) A third thermal conductivity filler (excluding silicon carbide) having a thermal conductivity of 60 W / mK to 300 W / mK and a peak in the particle size distribution in the range of 10 μm or more and 40 μm or less, With respect to 100 parts by mass of the (E) component, the total content of the (A) component to the (D) component is 1.0 to 10.0 parts by mass, and With respect to 100 parts by mass of the (E) component, the content of the (E-2) component is 28.0 parts by mass or less.

[0014] <Polyorganosiloxane having an alkenyl group bonded to a silicon atom> (A) The polyorganosiloxane having an alkenyl group bonded to a silicon atom is a component serving as a base polymer in the composition. Component (A) includes (A-1) a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in the molecule.

[0015] ≪(A-1) Polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in the molecule≫ (A-1) Component is a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in the molecule. By the addition reaction of the alkenyl group of component (A-1) and the hydrosilyl group (Si-H group) of component (B-1), a network structure is formed in the cured product of the composition.

[0016] (A-1) Component is not particularly limited as long as it can form the network structure together with component (B-1). Component (A-1) is typically represented by the general formula (I): (R 11 ) a1 (R 12 ) b1 SiO (4-a1-b1) / 2 (I) (In the formula, R 11 is an alkenyl group; R 12 is a monovalent hydrocarbon group having no aliphatic unsaturated bond; a1 is an integer from 1 to 3; b1 is an integer from 0 to 2, provided that a1 + b1 is from 1 to 3) and has two or more alkenyl group-containing siloxane units represented by the formula in the molecule. The number of alkenyl groups bonded to silicon atoms in component (A-1) is preferably from 2 to 100, more preferably from 2 to 50, in the molecule.

[0017] R 11 is preferably a vinyl group in terms of easy synthesis and not impairing the fluidity of the composition before curing and the heat resistance of the composition after curing. a is preferably 1 in terms of easy synthesis. R 12From the viewpoint of easy synthesis and excellent balance of properties such as mechanical strength and fluidity before curing, it is preferably a methyl group or a phenyl group, and particularly preferably a methyl group.

[0018] Examples of the organic group bonded to the silicon atom of the other siloxane unit in the component (A-1) include monovalent hydrocarbon groups having no aliphatic unsaturated bond. The organic group is R 12 For the same reason as above, it is preferably a methyl group or a phenyl group, and particularly preferably a methyl group.

[0019] R 11 may be present at either the end or in the middle of the molecular chain of the component (A-1), or may be present at both.

[0020] The siloxane skeleton of the component (A-1) can be linear or branched. That is, the component (A-1) can be (A-1-1) a linear polyorganosiloxane or (A-1-2) a branched polyorganosiloxane.

[0021] Examples of the (A-1-1) linear polyorganosiloxane include linear polyorganosiloxanes blocked at both ends with R3SiO 1 / 2 units and having only R 2 2SiO 2 / 2 units in the middle (where R is R 11 or R 12 , R 11 is an alkenyl group, R 12 is a monovalent hydrocarbon group having no aliphatic unsaturated bond, and the molecule contains two or more R 11 ). The R3SiO 1 / 2 unit in the component (A1-1) is preferably an R 11 R 12 2SiO 1 / 2 unit, an R 11 2R 12 SiO 1 / 2 unit or an R 11 3SiO 1 / 2 unit, and R 11 R 122SiO 1 / 2 It is particularly preferable that it is a unit.

[0022] (Component (A-1) has R at both ends 11 R 12 2SiO 1 / 2 units, and the intermediate units are blocked with R 12 2SiO 2 / 2 units, and it is more preferably a linear polyorganosiloxane composed only of R vi D n M vi represented linear polyorganosiloxane (i.e., both ends are blocked with M vi units (dimethylvinylsiloxane units), and the intermediate units are composed only of D units (dimethylsiloxane units) linear polyorganosiloxane). In this specification, "D n " means that the intermediate units are composed only of D units, where "n" means the degree of polymerization of the D units and is a value that varies according to the viscosity of the target polyorganosiloxane.

[0023] (As the branched polyorganosiloxane of (A-1-2), as essential units, SiO 4 / 2 units and R3SiO 1 / 2 units are included, and as optional units, R2SiO 2 / 2 units and / or RSiO 3 / 2 units are included, and branched polyorganosiloxanes are exemplified. Here, R is R 11 or R 12 , but in R, two or more per molecule are R 11 . In order to become a crosslinking point in the curing reaction, at least three Rs per molecule in R are R 11 , and the remainder is preferably R 12 . From the viewpoint that the cured product of the composition has excellent mechanical strength, the ratio of R3SiO 1 / 2 units to SiO 4 / 2 units is preferably in the range of 1:0.8 to 1:3 as a molar ratio, and is a resinous substance that is solid or viscous semi-solid at room temperature.

[0024] In the (A-1-2) component, R 11 may be present as R in the R3SiO 1 / 2 unit, or may be present as R in the R2SiO unit or the RSiO 3 / 2 unit. From the viewpoint of obtaining fast curing at room temperature, part or all of the R3SiO 1 / 2 units are preferably 11 R 12 2SiO 1 / 2 units.

[0025] ≪(A) component other than the (A-1) component≫ The (A) component may contain an (A) component other than the (A-1) component (hereinafter also referred to as the (A-2) component). Examples of the (A-2) component include a polyorganosiloxane having one alkenyl group bonded to a silicon atom in the molecule. The siloxane skeleton of the (A-2) component is as described above for the (A-1) component, including preferred embodiments.

[0026] The (A-2) component is preferably a linear polyorganosiloxane having one alkenyl group bonded to a silicon atom in the molecule. The (A-2) component is more preferably a linear polyorganosiloxane having one end blocked with an R 11 R 12 2SiO 1 / 2 unit, the other end blocked with an R 12 3SiO 1 / 2 unit, and the intermediate units consisting only of R 12 2SiO 2 / 2 units. Further, the (A-2) component is particularly preferably a linear polyorganosiloxane represented by M vi D n M.

[0027] ≪Preferred embodiments of the (A) component≫ (A) component preferably has a viscosity of 0.01 to 500 Pa·s at 23°C, more preferably 0.05 to 300 Pa·s, and particularly preferably 0.1 to 100 Pa·s. When the viscosity of the (A) component is within the above range, in the manufacturing process, it is easy to knead the filler and the polymer, and a composition with excellent electrical insulation properties, BLT properties, dischargeability, and heat dissipation properties of the final product can be obtained. Further, when the viscosity of the (A) component is 0.01 Pa·s or more at 23°C, the volatilization of low molecular components is suppressed in the manufacturing process, and the properties of the thermally conductive silicone composition can be efficiently satisfied. On the other hand, when the viscosity of the (A) component is 500 Pa·s or less at 23°C, the (E) component and the polymer components ((A) component and (B) component) are more likely to aggregate. Here, when the (A) component is a combination of two or more types, the viscosity of the (A) component means the viscosity of the mixed alkenyl group-containing polyorganosiloxane. In this specification, the viscosity is a value measured under the condition of 23°C by appropriately setting the spindle number and the rotation speed using a rotational viscometer in accordance with JIS K 6249.

[0028] (A) component may be one type of component or a combination of two or more types of components. For example, the (A) component may consist only of two or more types of (A-1) components, or may be a mixture of one or more types of (A-1) components and one or more types of (A-2) components.

[0029] <(B) Polyorganohydrogensiloxane having hydrogen atoms bonded to silicon atoms> (B) Polyorganohydrogensiloxane having hydrogen atoms bonded to silicon atoms contains (B-1) polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms in the molecule. The (B) component is not particularly limited as long as it can form the above-mentioned network structure together with the (A) component.

[0030] ≪(B-1) Polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms in the molecule≫ (Component (B-1) functions as a crosslinking agent for component (A). Component (B-1) is typically represented by general formula (II): (R 13 ) c H d SiO (4-c1-d1) / 2 (II) (In the formula, R 13 represents a monovalent hydrocarbon group having no aliphatic unsaturated bond; c1 is an integer from 0 to 2; d1 is an integer from 1 to 3, provided that c1 + d1 is an integer from 1 to 3) and has two or more units represented by this in the molecule.

[0031] R 13 is preferably a methyl group in terms of ease of synthesis. Also, d1 is preferably 1 in terms of ease of synthesis.

[0032] From the viewpoint of ease of synthesis, component (B-1) preferably has three or more siloxane units. Also, from the viewpoint of not volatilizing even when heated to the curing temperature and having excellent fluidity and being easily mixed with component (A), the number of siloxane units of component (B-1) is preferably 6 to 200, and particularly preferably 10 to 150. From the viewpoint of efficiently functioning as a crosslinking agent for component (A), component (B-1) preferably has three or more units represented by general formula (II) in the molecule.

[0033] The siloxane skeleton in component (B-1) may be linear, branched, or cyclic, and linear is preferred. In the case of component (B-1), the hydrogen atoms bonded to the silicon atoms may be present at the terminals or in the intermediate units, but are preferably present in the intermediate units.

[0034] (Component (B-1) has both ends independently blocked by R 14 3SiO 1 / 2 units, and the intermediate units are R 14 2SiO 2 / 2Linear polyorganohydrogensiloxane consisting only of units, and (B-1-2)R 14 3SiO 1 / 2 units and SiO 4 / 2 Polyorganohydrogensiloxane consisting only of units (in the above formulas, R 14 is, independently of each other, a hydrogen atom or a monovalent hydrocarbon group having no aliphatic unsaturated bond, provided that at least three of R 14 are hydrogen atoms) is preferred.

[0035] (In the case of the (B-1-1) component and the (B-1-2) component, R 14 3SiO 1 / 2 units include HR 15 2SiO 1 / 2 units and R 15 3SiO 1 / 2 units, and R 14 2SiO 2 / 2 units include HR 15 SiO 2 / 2 units and R 15 2SiO 2 / 2 units (in the above formulas, R 15 is a monovalent hydrocarbon group having no aliphatic unsaturated bond) are included.

[0036] (The (B-1) component is a linear polyorganohydrogensiloxane in which both ends are blocked with M H units (dimethylhydrogensiloxane units), and the intermediate units consist only of D units (dimethylsiloxane units) and D H units (dimethylsiloxane units), and a linear polyorganohydrogensiloxane in which both ends are blocked with M H units (dimethylhydrogensiloxane units), and the intermediate units consist only of D units (dimethylsiloxane units) is particularly preferred.

[0037] ≪Polyorganohydrogensiloxane other than the (B-1) component≫ (B) component can contain (B) components other than (B-1) component (hereinafter also referred to as (B-2) component). Examples of (B-2) component include polyorganohydrogensiloxane having one hydrogen atom bonded to a silicon atom in the molecule. The siloxane skeleton in the (B-2) component may be linear, branched or cyclic, and a linear one is preferred. Further, in the (B-2) component, the hydrogen atom bonded to the silicon atom may be present at the terminal or in the intermediate unit.

[0038] (B-2) component is M H D n It is particularly preferred that it is a linear polyorganohydrogensiloxane represented by M

[0039] ≪Preferred embodiments of (B) component≫ The viscosity of the (B) component is preferably 0.01 to 500 mPa·s, more preferably 1 to 300 mPa·s, and particularly preferably 5 to 100 mPa·s at 23°C. When the viscosity of the (B) component is within the above range, in the manufacturing process, it is easy to knead the (E) component and the polymer components ((A) component and (B) component), and a composition with more excellent electrical insulation properties, BLT properties, dischargeability and heat dissipation properties can be obtained. Note that the viscosity is as described above for the (A) component.

[0040] (B) component may be one kind of component or a combination of two or more kinds of components. For example, (B) component may consist only of two or more kinds of (B-1) components, or may be a mixture of one or more kinds of (B-1) components and one or more kinds of (B-2) components.

[0041] <Preferred embodiments of (A) component and (B) component> From the viewpoints of curability, heat resistance, and controlling the hardness of the material, the thermally conductive silicone composition preferably further contains at least one selected from the group consisting of (A-2) a polyorganosiloxane having one alkenyl group bonded to a silicon atom in the molecule, and (B-2) a polyorganohydrogensiloxane having one hydrogen atom bonded to a silicon atom in the molecule.

[0042] <(C) Platinum-based catalyst> (C) The platinum-based catalyst is a catalyst for promoting the addition reaction between the alkenyl group in component (A) and the hydrosilyl group in component (B).

[0043] (C) Examples of the component include platinum compounds such as chloroplatinic acid, reaction products of chloroplatinic acid and alcohol, platinum-olefin complexes, platinum-vinylsiloxane complexes, platinum-ketone complexes, and platinum-phosphine complexes. Among these, platinum-vinylsiloxane complexes are preferred from the viewpoint of good catalytic activity, and Karstedt complex, platinum-1,1,3,3-tetramethyl-1,3-divinyldisiloxane complex (platinum-methylvinylsiloxane dimer complex), Ashley complex, and platinum-2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane complex (platinum-methylvinylsiloxane tetramer complex) are particularly preferred because they cure in a short time at room temperature. (C) The component may be one component or a combination of two or more components.

[0044] <(D) Siloxane compound represented by the general formula (1)> (D) The component is represented by the following general formula (1):

Chemical formula

Chemical formula

[0045] (In the component (D), the units containing R 1 , the units containing R 2 , and the units represented by SiR 3 2O do not have to be arranged as shown in the general formula (1). For example, a unit represented by SiR 1 2O may be present between the unit containing R 2 and the unit containing R 3 .

[0046] The siloxane compound having a cyclic structure represented by the general formula (1) can introduce many hydrolyzable groups into the cyclic structure, and since they are concentrated positionally, the treatment efficiency of the component (E) is increased, making it possible to achieve higher filling. In addition, since the siloxane compound itself has high heat resistance, it can impart high heat resistance to the thermally conductive silicone composition. Further, the siloxane compound represented by the general formula (1) has an advantage that it can be easily obtained, for example, by subjecting a cyclic siloxane containing a hydrogen group, a siloxane having a vinyl group at one end, and a silane compound containing a vinyl group and a hydrolyzable group to an addition reaction.

[0047] R 1 is a group having an alkoxysilyl group having 1 to 4 carbon atoms, which is a hydrolyzable functional group. R1 may be directly bonded to X with silicon, or may be bonded by a linking group such as an ester bond. R 1 preferably has a group having the following structure. [Chemical formula]

[0048] R 1 From the point that the treatment efficiency of the thermal conductivity filler tends to be more improved, it is preferably a group having two or more, particularly three alkoxysilyl groups. Also, from the point that it is easy to obtain the raw material, R 1 preferably contains a methoxysilyl group.

[0049] R 2 is a linear organosiloxy group represented by the general formula (2). In the general formula (2), the number of d is an integer of 2 to 60. By the number of d being 2 to 60, the effect on fluidity can be enhanced, high loading is possible, and the viscosity of the siloxane compound itself can be suppressed. R 4 are each independently a monovalent hydrocarbon group having 1 to 12 carbon atoms, a linear or branched C 1-12 alkyl group, an aryl group such as phenyl or naphthyl, etc. are exemplified. Further, the hydrocarbon group may be substituted with a halogen such as chlorine, fluorine, bromine, etc., and as such a group, a perfluoroalkyl group such as a trifluoromethyl group is exemplified. Since synthesis is easy, R 4 is preferably a methyl group. Y is R 1 R 4 and a group selected from the group consisting of an aliphatic unsaturated group. The aliphatic unsaturated group preferably has 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms. Also, since the aliphatic unsaturated group makes the curing reaction likely to occur, it preferably has a double bond at the end. Since synthesis is easy, Y is preferably a methyl group or a vinyl group.

[0050] R 1 and R 2is bonded to the cyclic siloxane moiety of the siloxane represented by the general formula (1) via a group X. The group X is a divalent hydrocarbon group having 2 to 10 carbon atoms, and examples thereof include alkylene groups such as -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2-, -CH2CH(CH3)-, and -CH2CH(CH3)CH2-. From the viewpoint of easy synthesis, X is preferably -CH2CH2- or -CH2CH(CH3)-.

[0051] R 3 is each independently a monovalent hydrocarbon group having 1 to 6 carbon atoms or a hydrogen atom. Each R 3 may be the same or different. From the viewpoint of easy synthesis, R 3 is preferably a methyl group or a hydrogen atom.

[0052] a is an integer of 1 or more, preferably 1. b is an integer of 1 or more, preferably 1 or 2. c is an integer of 0 or more, preferably 0 to 2. Further, the sum of a + b + c is an integer of 4 or more, but preferably 4 from the viewpoint of easy synthesis.

[0053] Specific examples of the siloxane compound include compounds represented by the following structural formulas.

Chemical formula

[0054]

Chemical formula

[0055] (Component (D) may be one component or a combination of two or more components.

[0056] <(E) Thermal Conductive Filler> (E) The thermal conductive filler is as follows: (E-1) Silicon carbide having a peak in the particle size distribution in the range of 10 μm or more and 40 μm or less (E-2) A first thermally conductive filler having a thermal conductivity of 10 W / mK to 300 W / mK and having a peak in the particle size distribution in the range of 0.1 μm or more and 1.0 μm or less. (E-3) A second thermally conductive filler having a thermal conductivity of 10 W / mK to 300 W / mK and having a peak in the particle size distribution in the range of more than 1.0 μm and less than 10 μm, and (E-4) including a third thermally conductive filler (excluding silicon carbide) having a thermal conductivity of 60 W / mK to 300 W / mK and having a peak in the particle size distribution in the range of 10 μm or more and 40 μm or less.

[0057] ≪(E-1) Silicon carbide having a peak in the particle size distribution in the range of 10 μm or more and 40 μm or less≫ (E-1) component is silicon carbide having a peak in the particle size distribution in the range of 10 μm or more and 40 μm or less. The silicon carbide is not particularly limited as long as it is a grade that can be used as a thermally conductive filler, and commercially available products can be used. Commercially available products of silicon carbide include black silicon carbide or green silicon carbide manufactured by Pacific Random Co., Ltd. In addition, those obtained by ultrafine pulverization of these silicon carbides can also be used.

[0058] (E-1) When the component has a monodisperse particle size distribution, the peak of the particle size distribution of silicon carbide is synonymous with the average particle diameter. The average particle diameter can be obtained as a weight average value (or median diameter), etc. using a particle size distribution measuring device such as a laser light diffraction method.

[0059] (E-1) component preferably has a monodisperse particle size distribution. Further, the thermally conductive (E-1) component preferably has a peak in the particle size distribution in the range of 15 μm or more and 35 μm or less, and particularly preferably has a peak in the particle size distribution in the range of 20 μm or more and 30 μm or less. Further, from the viewpoints of electrical insulation characteristics, BLT characteristics, dischargeability, and heat dissipation, the BET specific surface area of the (E-1) component is 0.01 to 5.0 m 2 / g is preferable, and 0.5 to 3.0 m 2 / g is particularly preferable. The (E-1) component may be one component or a combination of two or more components.

[0060] Silicon carbide can be used as the (E-2) component and / or the (E-3) component described later. When silicon carbide is used as the (E-2) component and / or the (E-3) component, the silicon carbide contained in the composition may have at least two peaks in the particle size distribution, that is, a polydisperse particle size distribution. That is, the thermally conductive silicone composition contains silicon carbide having a peak in the particle size distribution in the range of 10 μm or more and 40 μm or less as the (E-1) component, and, as the (E-2) component, contains silicon carbide having a peak in the particle size distribution in the range of 0.1 μm or more and 1.0 μm or less, and / or, as the (E-3) component, can contain silicon carbide having a peak in the particle size distribution in the range of more than 1.0 μm and less than 10 μm.

[0061] ≪The first thermally conductive filler (E-2) having a thermal conductivity of 10 W / mK to 300 W / mK and having a peak in the particle size distribution in the range of 0.1 μm or more and 1.0 μm or less≫ In the (E-2) component, the thermal conductivity is a value measured by the laser flash method. Also, the peak of the particle size distribution is as described above for the (E-1) component. The (E-2) component is not particularly limited and can be appropriately selected from known components. The (E-2) component is preferably alumina (thermal conductivity: 30 W / mK), aluminum nitride (thermal conductivity: 180 W / mK), aluminum hydroxide (thermal conductivity: 11 W / mK), magnesium oxide (thermal conductivity: 60 W / mK), zinc oxide (thermal conductivity: 25 W / mK), crystalline silica (thermal conductivity: 10 W / mK), aluminum (thermal conductivity: 250 W / mK), boron nitride (thermal conductivity: 60 to 200 W / mK), and graphitized carbon (thermal conductivity: 100 to 250 W / mK). Also, from the viewpoints of electrical insulation properties, BLT properties, dischargeability, and heat dissipation, the BET specific surface area of the (E-2) component is preferably 0.01 to 5 m 2 / g, and particularly preferably 0.1 to 1 m 2 / g. The (E-2) component may be one component or a combination of two or more components.

[0062] <<The second thermally conductive filler having a thermal conductivity of 10 W / mK to 300 W / mK and having a peak in the particle size distribution in the range of more than 1.0 μm and less than 10 μm>> In the (E-3) component, the thermal conductivity is as described above in the (E-2) component. Also, the peak of the particle size distribution is as described above in the (E-1) component.

[0063] The (E-3) component is not particularly limited and can be appropriately selected from known components. The (E-3) component is preferably alumina, aluminum nitride, aluminum hydroxide, magnesium oxide, zinc oxide, crystalline silica, aluminum, boron nitride, and graphitized carbon. Also, from the viewpoints of electrical insulation properties, BLT properties, dischargeability, and heat dissipation, the BET specific surface area of the (E-3) component is preferably 0.1 to 3.0 m 2 / g, and particularly preferably 0.5 to 2.0 m 2 / g. The (E-3) component may be one component or a combination of two or more components.

[0064] <<The third thermally conductive filler (excluding silicon carbide) having a thermal conductivity of 60 W / mK to 300 W / mK and having a peak in the particle size distribution in the range of 10 μm or more and 40 μm or less>> In the (E-4) component, the thermal conductivity is as described above in the (E-2) component. Also, the peak of the particle size distribution is as described above in the (E-1) component.

[0065] The (E-4) component is not particularly limited and can be appropriately selected from known components. The (E-4) component is preferably aluminum nitride, boron nitride, and graphitized carbon. Also, from the viewpoints of electrical insulation properties, BLT properties, dischargeability, and heat dissipation, the BET specific surface area of the (E-4) component is preferably 0.01 to 1.0 m 2 / g, and particularly preferably 0.1 to 0.5 m 2 / g. (Component (E-4) may be one component or a combination of two or more components.)

[0066] ≪(E-5) Other Thermal Conductive Fillers≫ (Component (E) may contain (E-5) other thermal conductive fillers in addition to components (E-1) to (E-4).)

[0067] (Examples of component (E-5) include thermal conductive fillers having a thermal conductivity of 10 W / mK to 300 W / mK and having a peak in the particle size distribution in a range exceeding 40 μm (e.g., silicon carbide, aluminum nitride); and thermal conductive fillers having a thermal conductivity of 10 W / mK or more and less than 60 W / mK and having a peak in the particle size distribution in a range of 10 μm or more and 40 μm or less, etc. From the viewpoints of electrical insulation properties, BLT properties, dischargeability, and heat dissipation properties, the BET specific surface area of component (E-5) is preferably 0.1 to 3.0 m 2 / g, and particularly preferably 0.5 to 2.0 m 2 / g.)

[0068] (Component (E-5) may be one or a combination of two or more.)

[0069] <(F) Further Components> The composition may contain further components (F) such as reaction inhibitors, organic solvents, adhesion imparting agents, inorganic pigments, organic pigments, thixotropy imparting agents, viscosity modifiers, ultraviolet light absorbers, fungicides, heat resistance improvers, flame retardants, etc. within a range not impairing the effects of the present invention. Each of the components (F) may be one or a combination of two or more.)

[0070] <<Reaction Inhibitor>> Examples of the reaction inhibitor include organic compounds having a polar group in the molecule such as diallyl maleate; and organic compounds having an unsaturated bond such as acetylene alcohols and their derivatives. The reaction inhibitor suppresses the curing reaction rate of the composition and also contributes to improving the workability of handling and the balance between the expression of adhesiveness and the curing rate.)

[0071] <<Organic Solvent>> An organic solvent is a component capable of dissolving or dispersing the components contained in the composition. Examples of the organic solvent include aromatic organic solvents such as toluene and xylene.

[0072] <<Other (F) additional components>> The components other than the reaction inhibitor and the organic solvent can be appropriately selected from the components used in the thermally conductive silicone composition.

[0073] [Content] The content of each component in the thermally conductive silicone composition is as follows. Based on 100 parts by mass of the (E) component, the total content of the (A) component to the (D) component is 1.0 to 10.0 parts by mass. When the total content of the (A) component to the (D) component is less than 1.0 part by mass based on 100 parts by mass of the (E) component, the thermal conductivity tends to be high, but there is a concern that the amount of the polymer with respect to the (E) component is extremely small and the paste does not aggregate. When the total content of the (A) component to the (D) component exceeds 10.0 parts by mass based on 100 parts by mass of the (E) component, the dischargeability is good but the thermal conductivity becomes low. Based on 100 parts by mass of the (E) component, the total content of the (A) component to the (D) component is preferably 2.0 to 8.0 parts by mass, and particularly preferably 3.0 to 7.0 parts by mass. Also, based on 100 parts by mass of the (E) component, the total content of the (A) component to the (D) component may be 6.0 to 8.0 parts by mass.

[0074] Based on 100 parts by mass of the (E) component, the content of the (E-2) component is 28.0 parts by mass or less. When the content of the (E-2) component exceeds 28.0 parts by mass based on 100 parts by mass of the (E) component, the composition does not hold together. From the viewpoints of electrical insulation properties, BLT properties, dischargeability, and heat dissipation properties, based on 100 parts by mass of the (E) component, the content of the (E-2) component is preferably 10.0 to 28.0 parts by mass, and particularly preferably 15.0 to 25.0 parts by mass.

[0075] [Preferred content] The content of each component in the thermally conductive silicone composition is preferably as follows.

[0076] From the viewpoints of electrical insulation properties, BLT properties, dischargeability, and heat dissipation, the content of the (E-1) component is preferably 5.0 to 30.0 parts by mass, more preferably 10.0 to 30.0 parts by mass, and particularly preferably 10.0 to 25.0 parts by mass with respect to 100 parts by mass of the (E) component.

[0077] From the viewpoints of electrical insulation properties, BLT properties, dischargeability, and heat dissipation, the content of the (E-3) component is preferably 15.0 to 40.0 parts by mass, and particularly preferably 20.0 to 35.0 parts by mass with respect to 100 parts by mass of the (E) component.

[0078] From the viewpoints of electrical insulation properties, BLT properties, dischargeability, and heat dissipation, the content of the (E-4) component is preferably 5.0 to 40.0 parts by mass, and particularly preferably 20.0 to 35.0 parts by mass with respect to 100 parts by mass of the (E) component.

[0079] Therefore, with respect to 100 parts by mass of the (E) component, the content of the (E-1) component is 5.0 to 30.0 parts by mass, the content of the (E-2) component is 10.0 to 28.0 parts by mass, the content of the (E-3) component is 15.0 to 40.0 parts by mass, and the content of the (E-4) component is preferably 5.0 to 40.0 parts by mass.

[0080] From the viewpoints of dischargeability and curing properties, the content of the (A) component is preferably 55.0 to 95.0 parts by mass, more preferably 60.0 to 90.0 parts by mass, and particularly preferably 65.0 to 85.0 parts by mass with respect to 100 parts by mass in total of the (A), (B), (C), (D), and (F) components.

[0081] (B) The content is not particularly limited as long as it is an amount that forms a network structure in the cured product of the thermally conductive silicone composition. The ratio (H / Vi) of the number H of hydrogen atoms bonded to silicon atoms of component (B) to the number Vi of alkenyl groups of component (A) is preferably an amount such that it is 0.1 or more and less than 3.5, more preferably an amount such that it is 0.2 to 2.5, and particularly preferably an amount such that it is 0.3 to 2.0.

[0082] (C) The content is a catalytic amount with respect to the total amount of the thermally conductive silicone composition. Specifically, from the viewpoint of curability, the content of component (C) is preferably 0.1 to 1,000 weight ppm in terms of platinum metal atoms with respect to 100 parts by mass in total of components (A), (B), (C), (D), and (F), and particularly preferably 0.5 to 200 weight ppm.

[0083] (F) The content is not particularly limited as long as it does not impair the purpose of use of the thermally conductive silicone composition.

[0084] (Method for producing thermally conductive silicone composition) The thermally conductive silicone composition can be produced by uniformly kneading the essential components (A) to (E) and the optional component (F) by mixing means such as a universal kneader or a kneader.

[0085] (Cured product) The cured product obtained by curing the thermally conductive silicone composition can be obtained by curing the thermally conductive silicone composition. The curing conditions (i.e., heating temperature and heating time) can be appropriately adjusted according to the heat-resistant temperature of the member to which the thermally conductive silicone composition is applied. From the viewpoints of the heat resistance and workability of the member, the heating temperature is preferably 20 to 150°C, and particularly preferably more than 23°C and 100°C or less. The heating time depends on the amount of the material to be cured and the heating output of the curing equipment, but from the viewpoint of the simplicity of the curing process, it is preferably 15 minutes to 3 hours, and particularly preferably 30 minutes to 2 hours.

[0086] (Use) The cured product obtained by curing the thermally conductive silicone composition can be used as a heat dissipation member for electronic components such as electronic devices and integrated circuit elements. Therefore, electronic components containing the thermally conductive silicone composition are also the subject of the present invention.

Examples

[0087] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In these examples, "parts" indicates parts by mass, and "viscosity" indicates the viscosity at 23°C. The present invention is not limited by these examples.

[0088] (Components used) The components used in the examples and comparative examples are as follows. (A) Polyorganosiloxane having an alkenyl group bonded to a silicon atom (A-1): Vinyl dimethyl polysiloxane with vinyl groups at both ends: M vi D n M vi A linear vinyl dimethyl polysiloxane represented by and having a viscosity of 0.5 Pa·s (A-2): Vinyl dimethyl polysiloxane with a vinyl group at one end: M vi D n A linear vinyl dimethyl polysiloxane represented by M and having a viscosity of 0.03 Pa·s

[0089] (B) Polyorganohydrogensiloxane having a hydrogen atom bonded to a silicon atom (B-1): Hydrogen polysiloxane with a hydrogen atom at one end: M H D n A linear polymethylhydrogensiloxane represented by M (effective hydrogen content 0.04 mmol / g, viscosity 0.02 mPa·s) (B-2): Hydrogen polysiloxane with hydrogen atoms at both ends: M H D n M H A linear polymethylhydrogensiloxane represented by and having an effective hydrogen content of 1.2 mmol / g and a viscosity of 10 mPa·s (B-3): Hydrogen polysiloxane with side-chain hydrogen atoms at both ends: Both ends are MH Closed in units, with the intermediate units consisting only of D units and D H units, linear polymethylhydrogen siloxane (effective hydrogen content 2.6 mmol / g, viscosity 20 mPa·s)

[0090] (C) Platinum catalyst (C-1): Karstedt catalyst (platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, 2.0 mass% in terms of platinum atoms)

[0091] (D) Siloxane compound (D-1): [Chemical formula] A mixture of cyclic siloxane compounds represented by (n = 10 to 50)

[0092] (E) Thermal conductivity filler Since the thermal conductivity filler used in the examples is monodisperse, the peak diameter of the particle size distribution in the thermal conductivity filler used in the examples is synonymous with the "average particle diameter". Also, the "particle diameter" in the table indicates the "peak diameter of the particle size distribution". (E-1) Silicon carbide having a peak in the particle size distribution in the range of 10 μm or more and 40 μm or less (E-1-1): Silicon carbide (having a peak in the particle size distribution at 20 μm, thermal conductivity 200 W / mK, BET specific surface area 0.2 m 2 / g, supplier name Shinano Electric Refining Co., Ltd.) (E-1-2): Silicon carbide (having a peak in the particle size distribution at 25 μm, thermal conductivity 200 W / mK, BET specific surface area 0.1 m 2 / g, supplier name Shinano Electric Refining Co., Ltd.) (E-1-3): Silicon carbide (having a peak in the particle size distribution at 30 μm, thermal conductivity 200 W / mK, BET specific surface area 0.1 m 2 / g, supplier name Shinano Electric Refining Co., Ltd.) (E-2): The first thermal conductivity filler (E-2-1): Zinc Oxide (having a peak in the particle size distribution at 0.1 μm, thermal conductivity 25 W / mK, BET specific surface area 9.0 m 2 / g, supplier name: Zochem LLC) (E-2-2): Aluminum Nitride (having a peak in the particle size distribution at 0.1 μm, thermal conductivity 180 W / mK, BET specific surface area 2.8 m 2 / g, supplier name: Tokuyama Corporation) (E-2-3): Alumina (having a peak in the particle size distribution at 0.5 μm, thermal conductivity 30 W / mK, BET specific surface area 4.6 m 2 / g, supplier name: Sumitomo Chemical Co., Ltd.) (E-2-4): Silicon Carbide (having a peak in the particle size distribution at 0.5 μm, thermal conductivity 200 W / mK, BET specific surface area 5.0 m 2 / g, supplier name: Shinano Electric Refining Co., Ltd.) (E-2-5): Alumina (having a peak in the particle size distribution at 0.3 μm, thermal conductivity 30 W / mK, BET specific surface area 7.2 m 2 / g, supplier name: Sumitomo Chemical Co., Ltd.) (E-2-6): Alumina (having a peak in the particle size distribution at 0.8 μm, thermal conductivity 30 W / mK, BET specific surface area 2.1 m 2 / g, supplier name: Sumitomo Chemical Co., Ltd.) (E-3): Second Thermal Conductive Filler (E-3-1): Alumina (having a peak in the particle size distribution at 3.0 μm, thermal conductivity 30 W / mK, BET specific surface area 0.6 m 2 / g, supplier name: Sumitomo Chemical Co., Ltd.) (E-3-2): Alumina (having a peak in the particle size distribution at 5.0 μm, thermal conductivity 30 W / mK, BET specific surface area 0.3 m 2 / g, supplier name: Sumitomo Chemical Co., Ltd.) (E-3-3): Silicon Carbide (having a peak in the particle size distribution at 5.0 μm, thermal conductivity 200 W / mK, BET specific surface area 1.5 m 2 / g, supplier name: Shinano Electric Refining Co., Ltd.) (E-3-4): Alumina (having a peak in the particle size distribution at 2.0 μm, thermal conductivity 30 W / mK, BET specific surface area 1.0 m 2 / g, Supplier: Sumitomo Chemical Co., Ltd.) (E-3-5): Alumina (having a peak in the particle size distribution at 7.0 μm, thermal conductivity 30 W / mK, BET specific surface area 0.4 m 2 / g, Supplier: Sumitomo Chemical Co., Ltd.) (E-4): Third thermal conductive filler (E-4-1): Aluminum nitride (having a peak in the particle size distribution at 25 μm, thermal conductivity 180 W / mK, BET specific surface area 0.2 m 2 / g, Supplier: Toyo Aluminum Co., Ltd.) (E-5): Other thermal conductive fillers (E-5-1): Silicon carbide (having a peak in the particle size distribution at 60 μm, thermal conductivity 200 W / mK, BET specific surface area 0.2 m 2 / g, Supplier: Shinano Electric Refining Co., Ltd.) (E-5-2): Alumina (having a peak in the particle size distribution at 25 μm, thermal conductivity 30 W / mK, BET specific surface area 0.1 m 2 / g, Supplier: Sumitomo Chemical Co., Ltd.) (E-5-3): Aluminum nitride (having a peak in the particle size distribution at 60 μm, thermal conductivity 180 W / mK, BET specific surface area 0.1 m 2 / g, Supplier: Toyo Aluminum Co., Ltd.)

[0093] (F) Other components (F-1) Reaction inhibitor Dimethylbis(1,1-dimethyl-2-propynyloxy)silane (Supplier: Momentive Performance Materials Japan LLC)

[0094] (1) Preparation of base polymer (1) (silicone composition 1 excluding filler) The base polymer used in the examples and comparative examples was kneaded using a planetary mixer with the composition shown in Table 1 to prepare base polymer (1).

[0095] (2) Preparation of base polymer (2) (silicone composition 2 excluding filler) The base polymer (2) was prepared in the same manner as the base polymer (1) with the composition shown in Table 2.

[0096] (3) Preparation of thermally conductive silicone composition Examples 1 to 20, Comparative Examples 1 to 13 With the compositions shown in Tables 3 to 13, the thermally conductive filler and the base polymer of each component were blended, and kneading was carried out using a planetary mixer to prepare a thermally conductive silicone composition.

[0097] (Evaluation method) 1. Thermal conductivity Using a thermal conductivity meter (TPS 1500, manufactured by Kyoto Electronics Industry Co., Ltd.), the composition was filled into a plastic container with an inner diameter of 30 mm and a depth of 10 mm, left at 70 °C for 1 hour to cure the composition, and samples were produced. The sensors of the thermal conductivity meter were sandwiched between the two obtained samples, and the thermal conductivity was measured. The heat dissipation performance was judged according to the following criteria. When the thermal conductivity was 7.0 W / (m·K) or more, it was judged that the heat dissipation performance was excellent.

[0098] 2. Flow rate (dischargeability) The flow rate (g / min) of the composition was measured as follows and used for the evaluation of the dischargeability. (1) The composition was filled into a 30 cc EFD syringe manufactured by Nordson Corporation. (2) Using a high-precision dispenser SuperΣxIII with a correction function manufactured by Musashi Engineering Co., Ltd. as a dispenser, the composition was discharged at 0.625 MPa for 1 minute. (3) The discharged amount was weighed to obtain the flow rate (g / min) of the composition. When the flow rate was 20 g / min or more, it was judged that the dischargeability was excellent.

[0099] 3. BLT The measurement of BLT, i.e., the Bond Line Thickness of the heat dissipation material, was carried out as follows. Two silicon chips of 10 mm × 10 mm were prepared and their thicknesses were measured in advance. After applying 0.01 ml of the composition to the silicon chips after thickness measurement, they were sandwiched with silicon chips, a load of 100 N was applied, and then left at 70 °C for 1 hour. The thickness was measured using a micrometer. The thickness of BLT was calculated by subtracting the thickness of two silicon chips from the thickness after measurement. When the BLT was 60 μm or less, it was determined that the BLT of the composition was low.

[0100] 4. Dielectric breakdown voltage The dielectric breakdown voltage was measured in accordance with JIS K 6249. Using an electrical insulating oil breakdown voltage test device, Portatest A-2 (manufactured by Soken Electric Co., Ltd.), the dielectric breakdown voltage was measured. The composition was cured at 70 °C for 1 hour, and the voltage was applied to a test piece adjusted to a thickness of 1 mm at a rate of 2 kV / sec. The voltage at the time when the test piece became conductive and lost its electrical insulation was defined as the dielectric breakdown voltage. When the dielectric breakdown voltage was 1.0 kV / mm or more, it was determined that the electrical insulation of the composition was excellent.

[0101] 5. Volume resistivity The volume resistivity was measured in accordance with JIS K 6249. Specifically, using an Advantest R8340 digital ultra-high resistance / micro current meter (Advantest Corporation), the volume resistance was measured. The composition was cured at 70 °C for 1 hour, and a voltage of 500 V was applied to a test piece adjusted to a thickness of 1 mm. The volume resistivity was calculated from the current value obtained as the response value. When the volume resistivity was 1.00×10 12 Ω·cm or more, it was determined that the electrical insulation of the composition was excellent.

[0102]

Table 1

[0103]

Table 2

[0104]

Table 3

[0105]

Table 4

[0106]

Table 5

[0107]

Table 6

[0108]

Table 7

[0109]

Table 8

[0110]

Table 9

[0111]

Table 10

[0112]

Table 11

[0113]

Table 12

[0114]

Table 13

[0115] As is clear from the table, the thermal conductive silicone composition of the examples had a low BLT and was excellent in electrical insulation, dischargeability, and heat dissipation. That is, by setting the content of the (E) component with respect to the total content of the (A) to (D) components and the content of the (E-2) component with respect to the content of the (E) component within a predetermined range, it was possible to adjust the thermal conductivity and dischargeability while maintaining the characteristics of BLT. In particular, when comparing Example 1 and Example 10, when the amount of the "silicone composition excluding the filler" was large (that is, when the total content of the (A) to (D) components was 6.0 parts by mass or more with respect to 100 parts by mass of the (E) component), the BLT was lower and the dischargeability and heat dissipation were more excellent. When comparing Examples 1 to 3, when the amount of the (E-1) component was large, the heat dissipation was more excellent. When comparing Examples 1 and 2, when the amount of the (E-1) component was small, the electrical insulation was more excellent. Also, compared to Example 3, Examples 1 to 2 had a lower BLT and were more excellent in dischargeability. When comparing Examples 1, 4, and 7, when the particle diameter of the (E-1) component was large, the thermal conductivity was more excellent. Among Examples 1 to 9, Examples 1, 4, and 7 had a lower BLT and were more excellent in dischargeability.

[0116] The composition of Comparative Example 1 does not contain the (E-4) component. Therefore, the composition of Comparative Example 1 was inferior in dischargeability and electrical insulation to the compositions of Examples 1 to 3. The composition of Comparative Example 2 does not contain the (E-4) component. And the composition of Comparative Example 2 contains a thermal conductive filler having a peak of a large particle size distribution compared to the (E-4) component. Therefore, the composition of Comparative Example 2 was inferior in dischargeability to the composition of Example 1. The relationships between Examples 4 to 6 and Comparative Example 3, and between Examples 7 to 9 and Comparative Example 5 are the same as the relationship between Examples 1 to 3 and Comparative Example 1. Also, the relationships between Example 4 and Comparative Example 4, and between Example 7 and Comparative Example 6 are the same as the relationship between Example 1 and Comparative Example 2. The composition of Comparative Example 7 does not contain the (E-1) component and the (E-4) component. Therefore, the composition of Comparative Example 7 did not form a coherent composition. The composition of Comparative Example 8 does not contain the (E-1) component and the (E-4) component. And the composition of Comparative Example 4 contains silicon carbide having a peak with a large particle size distribution compared to the (E-1) component. Therefore, the composition of Comparative Example 8 was inferior in dischargeability and electrical insulation to the composition of Example 1. The composition of Comparative Example 9 contains a thermal conductivity filler having a lower thermal conductivity than the (E-4) component. Therefore, the composition of Comparative Example 9 was inferior in thermal conductivity. The composition of Comparative Example 10 does not contain the (E-4) component. Therefore, the composition of Comparative Example 10 was inferior in dischargeability and electrical insulation to the composition of Example 10. The composition of Comparative Example 11 does not contain the (E-4) component. Therefore, the composition of Comparative Example 11 was inferior in dischargeability and electrical insulation to the composition of Example 11. The compositions of Comparative Examples 12 and 13 have a content of the (E-2) component exceeding 28.0 parts by mass with respect to 100 parts by mass of the thermal conductivity filler. Therefore, the compositions of Comparative Examples 12 and 13 did not form a coherent composition.

Claims

1. (A)A polyorganosiloxane having an alkenyl group bonded to a silicon atom; (B)A polyorganohydrogensiloxane having a hydrogen atom bonded to a silicon atom; (C)A platinum-based catalyst; (D)The following general formula (1): 【Chemical 11】 〔In the formula, R １ : A group selected from the group consisting of the following groups 【Chemical Formula 12】 R ２ : The following general formula (2): 【Chemical 13】 (In the formula, R ４ is each independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms, where the alkyl group, the cycloalkyl group, the aryl group, and the aralkyl group are unsubstituted or substituted with a halogen or a cyano group, Y is R ４ , and d is an integer of 2 to 60) a linear organosiloxy group represented by X: Each independently, -CH₂CH₂-, -CH₂CH₂CH₂-, -CH₂CH₂CH₂CH₂CH₂CH₂-, -CH₂CH(CH₃)- or -CH₂CH(CH₃)CH₂- a and b: Each independently an integer of 1 or more c: An integer of 0 or more a + b + c: An integer of 4 or more R ３ : Each independently, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 carbon atoms, wherein the alkyl group, the cycloalkyl group, and the aryl group are unsubstituted or substituted with a halogen or a cyano group) A siloxane compound represented by, and (E)A thermal conductivity filler, A thermally conductive silicone composition comprising: Component (A) includes (A-1) a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in the molecule, Component (B) includes (B-1) a polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms in the molecule, Component (E) (E-1)Silicon carbide having a peak in the particle size distribution in the range of 10 μm or more and 40 μm or less, (E-2)A first thermal conductivity filler having a thermal conductivity of 10 W / mK to 300 W / mK and having a peak in the particle size distribution in the range of 0.1 μm or more and 1.0 μm or less, (E-3)A second thermal conductivity filler having a thermal conductivity of 10 W / mK to 300 W / mK and having a peak in the particle size distribution in the range of more than 1.0 μm and less than 10 μm, and (E-4)A third thermal conductivity filler (excluding silicon carbide) having a thermal conductivity of 60 W / mK to 300 W / mK and having a peak in the particle size distribution in the range of 10 μm or more and 40 μm or less, With respect to 100 parts by mass of component (E), the total content of components (A) to (D) is 1.0 to 10.0 parts by mass, and A thermally conductive silicone composition in which the content of component (E-2) is 28.0 parts by mass or less with respect to 100 parts by mass of component (E).

2. Component (E-2) is one or more selected from the group consisting of alumina, aluminum nitride, aluminum hydroxide, magnesium oxide, zinc oxide, crystalline silica, aluminum, boron nitride, and graphitized carbon, The (E-3) component is one or more selected from the group consisting of alumina, aluminum nitride, aluminum hydroxide, magnesium oxide, zinc oxide, crystalline silica, aluminum, boron nitride, and graphitized carbon, and The thermally conductive silicone composition according to claim 1, wherein the (E-4) component is one or more selected from the group consisting of aluminum nitride, boron nitride, and graphitized carbon. **Claim 3** Furthermore, the thermally conductive silicone composition according to claim 1, comprising one or more selected from the group consisting of a polyorganosiloxane having one alkenyl group bonded to a silicon atom in the molecule and a polyorganohydrogensiloxane having one hydrogen atom bonded to a silicon atom in the molecule. **Claim 4** Furthermore, the thermally conductive silicone composition according to claim 2, comprising one or more selected from the group consisting of a polyorganosiloxane having one alkenyl group bonded to a silicon atom in the molecule and a polyorganohydrogensiloxane having one hydrogen atom bonded to a silicon atom in the molecule. **Claim 5** With respect to 100 parts by mass of the (E) component, the content of the (E-1) component is 5.0 to 30.0 parts by mass, the content of the (E-2) component is 10.0 to 28.0 parts by mass, the content of the (E-3) component is 15.0 to 40.0 parts by mass, and the content of the (E-4) component is 5.0 to 40.0 parts by mass, The thermally conductive silicone composition according to claim 1. **Claim 6** With respect to 100 parts by mass of the (E) component, the content of the (E-1) component is 5.0 to 30.0 parts by mass, the content of the (E-2) component is 10.0 to 28.0 parts by mass, the content of the (E-3) component is 15.0 to 40.0 parts by mass, and the content of the (E-4) component is 5.0 to 40.0 parts by mass, The thermally conductive silicone composition according to claim 2. **Claim 7** With respect to 100 parts by mass of the (E) component, the content of the (E-1) component is 5.0 to 30.0 parts by mass, the content of the (E-2) component is 10.0 to 28.0 parts by mass, the content of the (E-3) component is 15.0 to 40.0 parts by mass, and the content of the (E-4) component is 5.0 to 40.0 parts by mass, The thermally conductive silicone composition according to claim 3. **Claim 8** With respect to 100 parts by mass of the (E) component, the content of the (E-1) component is 5.0 to 30.0 parts by mass, The content of the (E-2) component is 10.0 to 28.0 parts by mass, the content of the (E-3) component is 15.0 to 40.0 parts by mass, and the content of the (E-4) component is 5.0 to 40.0 parts by mass, The thermally conductive silicone composition according to claim 4.

9. A cured product obtained by curing the thermally conductive silicone composition according to any one of claims 1 to 8.

10. An electronic component comprising the thermally conductive silicone composition according to any one of claims 1 to 8.

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