Thermally conductive silicone composition and its cured product, and method for producing it.

Abstract

To provide a thermally conductive silicone composition with excellent storage properties and thermal conductivity. [Solution] (A) Organopolysiloxane (excluding component (D)), (B) Average sphericity of 0.8 or higher, with 30 hydroxyl groups / nm 2 The following are spherical aluminum oxide powders with an average particle size of 50-170 μm. (C) Spherical or irregularly shaped aluminum oxide powder with an average particle size of 0.1 to 5 μm. (D) Silane coupling agent, and (E) A cation exchange type and / or bi-ion exchange type ion trapping agent, on which one or more elements selected from Zr, Bi, Sb, Mg, and Al are supported: 0.01 to 10 parts by mass per 100 parts by mass of component (A), A thermally conductive silicone composition comprising the above-mentioned (B) component and (C) component, wherein the volume ratio of the blending ratio ((B):(C)) is 5:5 to 9.5:0.5.

Description

Technical Field

[0001] The present invention relates to a thermally conductive silicone composition having excellent thermal conductivity, a cured product thereof, and a manufacturing method. In particular, when used as a heat dissipation member for electronic components, it has excellent insulation and can be incorporated into electronic devices without damaging heat-generating electronic components such as power devices, transistors, thyristors, and CPUs (central processing units), and relates to a highly thermally conductive silicone composition having excellent thermal conductivity at high temperatures.

Background Art

[0002] In heat-generating electronic components such as power devices, transistors, thyristors, and CPUs, how to remove the heat generated during use has become an important issue. Conventionally, as such a heat removal method, it is generally practiced to attach heat-generating electronic components to heat dissipation fins or metal plates via an electrically insulating heat dissipation sheet to release heat, and as the heat dissipation sheet, a silicone resin in which a thermally conductive filler is dispersed is used.

[0003] In recent years, with the further high integration of circuits in electronic components, the amount of heat generated has also increased, and in some cases, the thermal conductivity at high temperatures such as 100°C or higher, especially in a 150°C environment, becomes important, and materials having higher thermal conductivity than before have been demanded. In order to improve the thermal conductivity of thermally conductive materials, a method of containing a filler showing high thermal conductivity such as aluminum oxide powder and aluminum nitride powder in a matrix resin has been generally used.

[0004] Therefore, in order to improve the thermal conductivity, a method of a highly thermally conductive resin composition has been proposed, which is defined by an average sphericity, a hydroxyl group amount, and spherical aluminum oxide powder having an average particle diameter of 10 to 50 μm, and an average particle diameter of 0.3 to 1 μm, a blending ratio with each aluminum oxide, and a volume ratio. However, when the average particle diameter of the spherical aluminum oxide powder is at most 50 μm, there is no regulation of the thermal conductivity at high temperatures, and there is a problem of insufficient thermal conductivity (Patent Document 1: Japanese Patent No. 5755977).

[0005] In addition, although a thermally conductive silicone composition using alumina powder having an average particle diameter of 0.1 to 100 μm has been proposed, specific regulations for the thermal conductivity and viscosity have not been made. Furthermore, a thermally conductive silicone composition defined by spherical alumina powder having an average particle diameter of 5 to 50 μm (excluding 5 μm) and spherical or amorphous alumina powder having an average particle diameter of 0.1 to 5 μm, and a blending ratio and weight ratio of each aluminum oxide have been proposed. However, there is no regulation of the average sphericity and hydroxyl group amount of the spherical alumina having a large average particle diameter, and there is a problem of insufficiency in achieving a high thermal conductivity at high temperatures (Patent Document 2: Japanese Patent No. 4646496).

[0006] Therefore, although a composition using spherical aluminum oxide with defined average sphericity, hydroxyl group amount, and average particle diameter as the main filler has been proposed, particularly in the curing form of the hydrosilylation reaction system, there remains a problem with the storage stability (Patent Document 3: International Publication No. 2018 / 088416).

[0007] To improve the storage stability of the hydrosilylation reaction system, it was effective to specify a particular amount of Na ions generated from aluminum oxide, to perform surface treatment of the aluminum oxide with a specific organohydrogenpolysiloxane during the manufacturing process of the composition, and to use a cation exchange type and / or dual ion exchange type ion trapping agent. However, although examples of the average particle size of aluminum oxide are provided, there is no description of the specifications for the average sphericity or the amount of hydroxyl groups, and it was difficult to achieve storage stability, especially in the cured form of the hydrosilylation reaction system, when aiming for even higher thermal conductivity (Patent Document 4: Japanese Patent Application Publication No. 2021-187874). [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Patent No. 5755977 [Patent Document 2] Patent No. 4646496 [Patent Document 3] International Publication No. 2018 / 088416 [Patent Document 4] Japanese Patent Publication No. 2021-187874 [Overview of the project] [Problems that the invention aims to solve]

[0009] This invention has been made in view of the above circumstances, and aims to provide a thermally conductive silicone composition that has excellent storage properties and thermal conductivity. [Means for solving the problem]

[0010] As a result of diligent research to achieve the above objective, the inventors of the present invention have found that the above problems can be solved by adopting the configuration described in item 1 below, and have thus come to the present invention.

[0011] Accordingly, the present invention provides the following invention. 1. (A) Organopolysiloxanes (excluding component (D)), (B) Average sphericity of 0.8 or higher, with 30 hydroxyl groups / nm 2 The following are spherical aluminum oxide powders with an average particle size of 50-170 μm. (C) Spherical or irregularly shaped aluminum oxide powder with an average particle size of 0.1 to 5 μm. (D) The following formula (1) -SiR 11 (3-α) (OR 12 ) α (1) (In the formula, R 11 R is independently an unsubstituted or substituted monovalent hydrocarbon group. 12 (The group is independently selected from alkyl groups, alkoxyalkyl groups, alkenyl groups, and acyl groups, and α is 1, 2, or 3.) An organopolysiloxane having at least one silyl group represented by in one molecule and having a viscosity of 0.01 to 30 Pa·s at 25°C, and (E) An ion trapping agent selected from cation exchange type and dual ion exchange type, and on which one or more elements selected from Zr, Bi, Sb, Mg and Al are supported: 0.01 to 10 parts by mass per 100 parts by mass of component (A) above. A thermally conductive silicone composition comprising the above-mentioned (B) component and (C) component, wherein the volume ratio of the blending ratio ((B):(C)) is 5:5 to 9.5:0.5. 2. The thermally conductive silicone composition according to claim 1, wherein the total amount of component (B) and component (C) is 80 to 87 volume percent of the thermally conductive silicone composition, the thermal conductivity of the thermally conductive silicone composition at 25°C is 5.0 W / m·K or higher as measured by the hot disk method in accordance with ISO 22007-2, and the viscosity at 25°C is 30 to 800 Pa·s as measured by a spiral viscometer at a rotation speed of 10 rpm. 3. The thermally conductive silicone composition is an addition reaction curable silicone composition, (A) Component is, (AI) The following formula (I-1) [ka] (In the formula, R 1 is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, and R 2 is an alkenyl group, and a1, a2, b1, b2, b3, c1, c2, and d are numbers satisfying a1≧0, a2≧0, b1≧0, b2≧0, b3≧0, c1≧0, c2≧0, and d≧0, a2 + b2 + b3 + c2>0, and a1 + a2 + b1 + b2 + b3 + c1 + c2 + d = 1 respectively.) An organopolysiloxane having an alkenyl group bonded to a silicon atom, represented by (I-2) The following formula (I-2)

Chemical formula

[0012] According to the present invention, it is possible to provide a thermally conductive silicone composition that is excellent in terms of storage properties and thermal conductivity and is suitable as a heat dissipation material for electronic components, without specifying a particular amount of Na ions generated from aluminum oxide, and without performing surface treatment of aluminum oxide with a specific organohydrogen polysiloxane in the manufacturing process of the composition. [Modes for carrying out the invention]

[0013] The thermally conductive silicone compositions of the present invention will be described in detail below, but the present invention is not limited to these.

[0014] The present invention will be described in detail below. The "thermal conductive silicone composition" may be abbreviated as "composition." [(A) component] (A) The organopolysiloxane is the main component of the silicone composition of the present invention and can be used alone or in combination of two or more. The molecular structure of the organopolysiloxane is not limited, but linear or partially branched linear is preferred. Examples of such organopolysiloxanes include single polymers having these molecular structures, copolymers consisting of these molecular structures, or mixtures of these polymers. Examples of groups bonded to the silicon atom in the organopolysiloxane include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl groups; isopropyl, tertiary butyl, isobutyl, 2-methylundecyl, 1 Examples include branched alkyl groups such as hexylheptyl group; cyclic alkyl groups such as cyclopentyl group, cyclohexyl group, and cyclododecyl group; alkenyl groups such as vinyl group, allyl group, butenyl group, pentenyl group, and hexenyl group; aryl groups such as phenyl group, tolyl group, and xylyl group; aralkyl groups such as benzyl group, phenethyl group, and 2-(2,4,6-trimethylphenyl)propyl group; and halogenated alkyl groups such as 3,3,3-trifluoropropyl group and 3-chloropropyl group. Details of component (A) will be described later.

[0015] The viscosity of component (A) at 25°C is not limited, but is preferably 20 to 100,000 mPa·s, more preferably 50 to 70,000 mPa·s, even more preferably 70 to 50,000 mPa·s, and particularly preferably 100 to 10,000 mPa·s. Increasing the viscosity above the lower limit improves the physical properties of the resulting cured product. On the other hand, keeping it below the upper limit of the above range improves the handling properties of the silicone composition. In the present invention, the viscosity of each component may be expressed as rotational viscosity and kinematic viscosity. Rotational viscosity is the value measured using a BM-type viscometer or BH-type viscometer (for example, manufactured by Tokyo Keiki Co., Ltd.) at 25°C, and the rotor, rotation speed, and rotation time are appropriately selected according to the viscosity based on conventional methods. Kinematic viscosity is the value measured using an Ostwald-type viscometer.

[0016] (A) The amount of component is preferably 0.5 to 4.0% by mass in the composition, and more preferably 0.7 to 3.0% by mass.

[0017] [(B) Component] (B) Component has an average sphericity of 0.8 or higher and 30 hydroxyl groups / nm. 2 The following is a spherical aluminum oxide powder with an average particle size of 50 to 170 μm. Multiple types with different average particle sizes may be used in combination, as long as they meet the above range.

[0018] The crystalline structure of aluminum oxide powder can be either single-crystal or polycrystalline, but the α-phase is preferred from the viewpoint of high thermal conductivity, and the specific gravity is 3.7 g / cm³. 3 ) or higher is preferable. By setting the specific gravity to 3.7 or higher, the proportion of voids and low-crystalline phases present inside the particles can be reduced, thereby further increasing the thermal conductivity. The particle size of aluminum oxide powder can be adjusted by classification and mixing operations.

[0019] The average sphericity is 0.8 or higher, preferably 0.80 or higher, more preferably 0.85 or higher, even more preferably 0.9 or higher, and particularly preferably 0.90 or higher. If the average sphericity is less than 0.8, the contact between particles becomes significant, the surface irregularities of the sheet become larger, the interfacial thermal resistance increases, and the thermal conductivity may deteriorate. Furthermore, the capture rate of Na+ ions generated by component (B) by component (E), described later, may deteriorate. There is no upper limit to the average sphericity, but it can be set to, for example, 1.00.

[0020] In this invention, the average sphericity can be measured by importing particle images captured with a scanning electron microscope into an image analysis device, such as the JEOL JSM-7500F, as follows: The projected area (X) and perimeter (Z) of the particle are measured from the photograph. If (Y) is the area of ​​a perfect circle corresponding to the perimeter (Z), then the sphericity of the particle can be expressed as X / Y. Therefore, assuming a perfect circle with the same perimeter (Z) as the sample particle, Z = 2πr and Y = πr 2 Therefore, Y = π × (Z / 2π) 2 Therefore, the sphericity of each particle is given by: Sphericity = X / Y = X × 4π / Z 2 It can be calculated as follows. The sphericity of 100 arbitrary particles obtained in this way is determined, and the average value is taken as the mean sphericity.

[0021] Hydroxyl groups: 30 per nm 2 The following applies: 28 particles / nm 2 The following is preferable: 25 particles / nm 2 The following is more preferable: 30 hydroxyl groups / nm 2 If this value is exceeded, the fillability of the resin may deteriorate, potentially leading to poor thermal conductivity. There is no lower limit for the surface hydroxyl groups, but for example, 5 groups / nm 2 It can be done this way.

[0022] The number of hydroxyl groups in this invention, i.e., the surface hydroxyl group concentration, can be measured by Karl Fischer coulometric titration, for example, using the Mitsubishi Chemical Corporation's "Trace Moisture Analyzer CA-100". Specifically, 0.3 to 1.0 g of the sample is placed in a moisture vaporizer, and the sample is heated using an electric heater while supplying dehydrated argon gas as a carrier gas. In the Karl Fischer coulometric titration, the amount of moisture generated between 200°C and 900°C is defined as the amount of surface hydroxyl groups. The concentration of surface hydroxyl groups is calculated from the measured amount of moisture and specific surface area.

[0023] The average particle diameter is 50 to 170 μm, preferably 55 to 160 μm, and more preferably 60 to 150 μm. If the average particle diameter is less than 50 μm, the contact between particles decreases, which may lead to an increase in interparticle contact thermal resistance and a decrease in thermal conductivity. If it exceeds 170 μm, the surface irregularities of the sheet become larger, which may increase the interfacial thermal resistance and a decrease in thermal conductivity.

[0024] In this invention, the average particle size can be measured using a laser diffraction particle size distribution analyzer, for example, the Shimadzu Corporation's "Laser Diffraction Particle Size Distribution Analyzer SALD-2300". For the evaluation sample, 5g of the thermal conductive powder to be measured is added to 50cc of pure water in a glass beaker, stirred with a spatula, and then dispersed in an ultrasonic cleaner for 10 minutes. The dispersed thermal conductive powder solution is added drop by drop to the sampler section of the analyzer using a dropper, and the sample is allowed to stabilize until the absorbance can be measured. Measurement is then performed once the absorbance has stabilized. The laser diffraction particle size distribution analyzer calculates the particle size distribution from the light intensity distribution data of the diffracted / scattered light from the particles detected by the sensor. The average particle size is obtained by multiplying the measured particle size by the relative particle amount (difference %) and dividing by the total relative particle amount (100%). Note that the average particle size is the average diameter of the particles.

[0025] [(C) component] Component (C) is spherical or irregularly shaped aluminum oxide powder with an average particle diameter of 0.1 to 5 μm. It may be used alone or in combination of two or more types with different average particle diameters. The average particle diameter is 0.1 to 5 μm, preferably 0.5 to 5 μm, and more preferably 0.6 to 3 μm. Irregularly shaped particles are those that are not spherical. If the average particle diameter is less than 0.1 μm, contact between particles decreases, which may lead to increased interparticle contact thermal resistance and poor thermal conductivity. On the other hand, if it exceeds 5 μm, the surface irregularities of the sheet become larger, which may increase interfacial thermal resistance and poor thermal conductivity. Furthermore, component (E), described later, contains Na produced by component (C). + There is a risk that the ion capture rate will be reduced.

[0026] If component (C) is spherical, then, similar to component (B), the average sphericity must be 0.8 or higher, and there must be 30 hydroxyl groups / nm. 2 The following is preferable:

[0027] The volume ratio of the above-mentioned components (B):(C) is 5:5 to 9.5:0.5, preferably 5.0:5.0 to 9.5:0.5, and more preferably 6:4 to 9:1. If the proportion of component (B) is less than 5 by volume (combining components (B) and (C) to 10, and so on), the filler's packing ability may be poor. On the other hand, if it is greater than 9.5, it may become difficult to pack the filler densely, and the thermal conductivity may decrease.

[0028] The total amount of component (B) and component (C) is preferably 80 to 87 volume%, and more preferably 80 to 86 volume%, of the thermally conductive silicone composition. By making the total amount of component (B) and component (C) 80 volume% or more, the thermal conductivity of the composition is further improved, while if it exceeds 87 volume%, it may become difficult to fill with thermally conductive filler.

[0029] [(D) component] Component (D) of the present invention is the following general formula (1) -SiR 11 (3-α) (OR 12 ) α (1) (In the formula, R 11 R is independently an unsubstituted or substituted monovalent hydrocarbon group. 12 (The group is independently selected from alkyl groups, alkoxyalkyl groups, alkenyl groups, and acyl groups, and α is 1, 2, or 3.) The organopolysiloxane contains at least one silyl group represented by in one molecule and has a viscosity of 0.01 to 30 Pa·s at 25°C, and can be used alone or in combination of two or more. Component (D) allows for the creation of compositions with good handling and workability, even when components (B) and (C) are present in large quantities.

[0030] An organopolysiloxane having at least one silyl group represented by the following general formula (1) in one molecule is the following general formula (2): [ka] (In the formula, R 11 R is independently an unsubstituted or substituted monovalent hydrocarbon group. 12 (α is independently selected from alkyl groups, alkoxyalkyl groups, alkenyl groups, and acyl groups, α is 1, 2, or 3, and β is an integer from 2 to 100.) Examples of organopolysiloxanes represented by [formula] include [formula].

[0031] Of the above (1) and (2), R 11Each is independently an unsubstituted or substituted monovalent hydrocarbon group, preferably having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 3 carbon atoms. Specifically, examples include linear alkyl groups, branched alkyl groups, cyclic alkyl groups, alkenyl groups, aryl groups, aralkyl groups, and halogenated alkyl groups. Examples of linear alkyl groups include methyl, ethyl, propyl, hexyl, octyl, and decyl groups. Examples of branched alkyl groups include isopropyl, isobutyl, tert-butyl, and 2-ethylhexyl groups. Examples of cyclic alkyl groups include cyclopentyl and cyclohexyl groups. Examples of alkenyl groups include vinyl and allyl groups. Examples of aryl groups include phenyl and tolyl groups. Examples of aralkyl groups include 2-phenylethyl and 2-methyl-2-phenylethyl groups. Examples of alkyl halides include 3,3,3-trifluoropropyl group, 2-(nonafluorobutyl)ethyl group, and 2-(heptadecafluorooctyl)ethyl group. 11 A methyl group or a phenyl group is preferred.

[0032] The above R 12 R is independently selected from alkyl groups, alkoxyalkyl groups, alkenyl groups, and acyl groups. Examples of alkyl groups include R 11 Examples of monovalent hydrocarbon groups, similar to those exemplified in [reference], are unsubstituted or substituted, preferably having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 3 carbon atoms. These include linear alkyl groups, branched alkyl groups, and cyclic alkyl groups. Examples of alkoxyalkyl groups include methoxyethyl groups and methoxypropyl groups. Examples of alkenyl groups include R 11 Examples of acyl groups include those similar to those exemplified in [reference]. Examples of acyl groups include acetyl groups and octanoyl groups. 12 The group is preferably an alkyl group, and more preferably a methyl group or an ethyl group. α is 1, 2, or 3, with 3 being preferred. β is 2 to 100, with 5 to 50 being preferred.

[0033] (D) Suitable specific examples of organopolysiloxanes of component (D) are listed below. [ka] (In the formula, Me represents a methyl group.)

[0034] The viscosity of component (D), the organopolysiloxane, at 25°C is 0.01 to 30 Pa·s, with 0.01 to 10 Pa·s being preferred. A viscosity of 0.01 Pa·s or higher suppresses oil bleeding and sagging from the resulting silicone composition. A viscosity of 30 Pa·s or lower improves the fluidity of the resulting silicone composition, making application easier.

[0035] The amount of component (D) is preferably 10 to 900 parts by mass, and more preferably 20 to 700 parts by mass, per 100 parts by mass of component (A). By using 5 parts by mass or more of component (D), a softer composition can be obtained after heating. By using 900 parts by mass or less, it becomes easier to harden.

[0036] [(E) component] Component (E) is an ion trapping agent selected from cation exchange type and dual ion exchange type, and may be any of cation exchange type, dual ion exchange type, cation exchange type, or dual ion exchange type. It is an ion trapping agent on which one or more elements selected from Zr, Bi, Sb, Mg, and Al are supported, and can be used alone or in combination of two or more. Na contained in components (B) and (C) of the composition of the present invention + When the composition described later is cured by a hydrosilylation reaction due to ions, component (F) is a curing agent that has an average of two or more silicon-bonded hydrogen atoms per molecule, and is a component that can suppress the deterioration of the platinum-based catalyst over time. Therefore, anion exchange type trapping agents are not suitable in the present invention.

[0037] Component (E) is not particularly limited in other respects, but its support is preferably one or more selected from, for example, hydrotalcites and inorganic ion exchangers such as polyvalent metal acid salts. Among these, it is particularly preferable that it be supported by hydrotalcites from the viewpoint of improving the storage properties of the composition of the present invention.

[0038] The amount of elemental support for component (E) is preferably 0.1 to 10 meq / g, and more preferably 1 to 8 meq / g, as the total exchange amount of each ion. Within this range, the storage properties of the composition of the present invention can be more effectively improved. The total exchange amount of ions refers to the amount of ion exchange in 0.1N hydrochloric acid or 0.1N aqueous sodium hydroxide solution.

[0039] (E) For component (E), commercially available products such as IXE-100, IXE-600, IXEPLAS-A1, and IXEPLAS-A2 (manufactured by Toagosei Co., Ltd.) can be used.

[0040] The amount of component (E) is 0.01 to 10 parts by mass per 100 parts by mass of component (A), preferably 0.1 to 9 parts by mass, and more preferably 0.5 to 8 parts by mass. If the amount of component (E) is less than 0.01 parts by mass, the deterioration of component (G) over time, which will be described later, may not be suppressed, and if the amount of component (E) exceeds 10 parts by mass, appropriate curability may not be obtained.

[0041] [Curable composition] This composition can also be further modified by adding a curing agent to make it a curable composition. In this case, the curing mechanism of this composition is not limited and includes, for example, an addition reaction (hydrosilylation reaction), a condensation reaction, and a radical reaction with an organic peroxide. An addition reaction (hydrosilylation reaction) is preferred because it cures quickly and does not generate by-products.

[0042] [Addition reaction curable silicone composition] In the case of an addition-curable silicone composition, (A) component is, (AI) The following formula (I-1) [ka] (In the formula, R 1 R is independently an unsubstituted or substituted monovalent hydrocarbon group that does not have an aliphatic unsaturated bond, 2 (where a1 is an alkenyl group, and a1, a2, b1, b2, b3, c1, c2, and d satisfy a1≧0, a2≧0, b1≧0, b2≧0, b3≧0, c1≧0, c2≧0, and d≧0 respectively, and a2+b2+b3+c2>0.) This is an organopolysiloxane having an alkenyl group bonded to a silicon atom, and further, (I-2) The following formula (I-2) [ka] (In the formula, R 3 Independently, e1, e2, f1, f2, f3, g1, g2, and h are unsubstituted or substituted monovalent hydrocarbon groups without aliphatic unsaturated bonds, and e1≧0, e2≧0, f1≧0, f2≧0, f3≧0, g1≧0, g2≧0, and h≧0, respectively, and e2+f2+f3+g2>0. Organohydrogenpolysiloxanes having hydrogen atoms bonded to silicon atoms, and (I-3) Platinum group metal curing catalyst Examples include those that include:

[0043] [(AI) Organopolysiloxane having an alkenyl group bonded to a silicon atom] The (AI) component is given by the following formula (I-1). [ka] (In the formula, R 1 R is independently an unsubstituted or substituted monovalent hydrocarbon group that does not have an aliphatic unsaturated bond, 2 (where a1 is an alkenyl group, and a1, a2, b1, b2, b3, c1, c2, and d satisfy a1≧0, a2≧0, b1≧0, b2≧0, b3≧0, c1≧0, c2≧0, and d≧0 respectively, and a2+b2+b3+c2>0.) This is an organopolysiloxane having alkenyl groups bonded to silicon atoms, and can be used alone or in combination of two or more types. In particular, it is preferable to have an organopolysiloxane having an average of 0.1 or more silicon-bonded alkenyl groups per molecule. More preferably, the average number of silicon-bonded alkenyl groups is 0.5 or more, and even more preferably 0.8 or more. This is because the resulting composition hardens more sufficiently when the average number of silicon-bonded alkenyl groups per molecule is above the above range.

[0044] In the above equation (I-1), R 1 These are independently unsubstituted or substituted monovalent hydrocarbon groups that do not have aliphatic unsaturated bonds, and specifically include linear alkyl groups, branched alkyl groups, cyclic alkyl groups, aryl groups, aralkyl groups, halogenated alkyl groups, etc. Among these, groups bonded to silicon atoms other than alkenyl groups in organopolysiloxanes include linear alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, isopropyl group, tert-butyl group, isobutyl group, 2-methylundecyl group, Examples include branched alkyl groups such as 1-hexylheptyl group, cyclic alkyl groups such as cyclopentyl group, cyclohexyl group, and cyclododecyl group, aryl groups such as phenyl group, tolyl group, and xylyl group, aralkyl groups such as benzyl group, phenethyl group, and 2-(2,4,6-trimethylphenyl)propyl group, and halogenated alkyl groups such as 3,3,3-trifluoropropyl group and 3-chloropropyl group. Alkyl and aryl groups are preferred, and methyl and phenyl groups are more preferred.

[0045] a1, a2, b1, b2, b3, c1, c2, and d are such that a1≧0, a2≧0, b1≧0, b2≧0, b3≧0, c1≧0, c2≧0, and d≧0, respectively, and 0≦a1≦2, Preferably, 1≦a2≦2, 50≦b1≦1,200, 0≦b2≦20, 0≦b3≦10, 0≦c1≦5, 0≦c2≦5, and 0≦d≦5; more preferably, 55≦b1≦1,000, 0≦b2≦10, and 0≦b3≦5. A2+b2+b3+c2>0 and a2+b2+b3+c2>1 are preferred.

[0046] The molecular structure of organopolysiloxanes is not limited and can include, for example, linear, branched, partially branched linear, cyclic, and dendritic (dendrimer) structures. Examples of such organopolysiloxanes include monopolymers having these molecular structures, copolymers consisting of these molecular structures, or mixtures thereof.

[0047] Examples of organopolysiloxanes include dimethylpolysiloxane with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, dimethylpolysiloxane with methylphenylvinylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane-methylphenylsiloxane copolymer with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane-methylvinylsiloxane copolymer with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane-methylvinylsiloxane copolymer with trimethylsiloxy groups sealed at both ends of the molecular chain, methyl(3,3,3-trifluoropropyl)polysiloxane with dimethylvinylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane-methylvinylsiloxane copolymer with silanol groups sealed at both ends of the molecular chain, and dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer with silanol groups sealed at both ends of the molecular chain. Formula: (CH3)3SiO 1 / 2 Siloxane units and formula represented by: (CH3)2(CH2=CH)SiO 1 / 2 Siloxane units and formula: CH3SiO 3 / 2 Siloxane units and formula represented by: (CH3)2SiO 2 / 2Examples include organosiloxane copolymers consisting of siloxane units represented by , dimethylpolysiloxane with silanol groups sealed at both ends of the molecular chain, dimethylsiloxane-methylphenylsiloxane copolymer with silanol groups sealed at both ends of the molecular chain, dimethylpolysiloxane with trimethoxysiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane-methylphenylsiloxane copolymer with trimethoxysilyl groups sealed at both ends of the molecular chain, dimethylpolysiloxane with methyldimethoxysiloxy groups sealed at both ends of the molecular chain, dimethylpolysiloxane with triethoxysiloxy groups sealed at both ends of the molecular chain, dimethylpolysiloxane with trimethoxysilylethyl groups sealed at both ends of the molecular chain, and mixtures of two or more of these.

[0048] [(I-2): Organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms (hereinafter sometimes referred to as component (F)).] The (I-2) component is given by the following formula (I-2): [ka] (In the formula, R 3 Independently, e1, e2, f1, f2, f3, g1, g2, and h are unsubstituted or substituted monovalent hydrocarbon groups without aliphatic unsaturated bonds, and e1≧0, e2≧0, f1≧0, f2≧0, f3≧0, g1≧0, g2≧0, and h≧0, respectively, and e2+f2+f3+g2>0. The organohydrogenpolysiloxane, represented by [formula], has hydrogen atoms bonded to silicon atoms and can be used alone or in combination of two or more types. It is preferable that each molecule has an average of two or more hydrogen atoms bonded to silicon atoms. The viscosity of the organohydrogenpolysiloxane at 25°C is not limited, but is preferably 1 to 100,000 mPa·s, and more preferably 1 to 5,000 mPa·s. Note that viscosity may also be described separately as kinematic viscosity.

[0049] R 3 R is independently an unsubstituted or substituted monovalent hydrocarbon group that does not have an aliphatic unsaturated bond, and R of formula (I-1) above 1Similar and preferred examples are given. The organohydrogenpolysiloxane may be linear or branched. For example, dimethylpolysiloxane with dimethylhydrogensiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane-methylhydrogensiloxane copolymer with trimethylsiloxy groups sealed at both ends of the molecular chain, dimethylsiloxane-methylhydrogensiloxane copolymer with dimethylhydrogensiloxy groups sealed at both ends of the molecular chain, formula: (CH3)3SiO 1 / 2 Siloxane units and formula represented by: (CH3)2HSiO 1 / 2 Siloxane units and formula represented by: SiO 4 / 2 Examples include organosiloxane copolymers consisting of siloxane units represented by , and mixtures of two or more thereof.

[0050] e1, e2, f1, f2, f3, g1, g2, and h are such that e1≧0, e2≧0, f1≧0, f2≧0, f3≧0, g1≧0, g2≧0, and h≧0, respectively, and it is preferable that 0≦e1≦2, 1≦e2≦2, 0≦f1≦600, 1≦f2≦110, 0≦f3≦5, 0≦g1≦3, 0≦g2≦3, and 0≦h≦3. It is more preferable that 1≦f1≦500, 2≦f2≦100, and 0≦f3≦3. It is preferable that e2+f2+f3+g2>0 and e2+f2+f3+g2>2.

[0051] The amount of organohydrogenpolysiloxane used in this composition is the amount necessary for curing. Specifically, for every mole of silicon-bonded alkenyl groups in component (Al), the amount of silicon-bonded hydrogen atoms in the organohydrogenpolysiloxane is preferably 0.1 to 10 moles, more preferably 0.1 to 5 moles, and even more preferably 0.1 to 3.0 moles. Setting the amount above the lower limit provides sufficient curability, while setting it below the upper limit results in a very hard cured product, preventing the formation of numerous cracks on the surface.

[0052] [(I-3): Platinum group metal-based curing catalyst (hereinafter sometimes referred to as component (G)).] Platinum group metal-based curing catalysts are catalysts used to accelerate the curing of compositions, and examples include chloroplatinic acid, alcoholic solutions of chloroplatinic acid, platinum olefin complexes, platinum alkenylsiloxane complexes, and platinum carbonyl complexes.

[0053] In this composition, the amount of platinum group metal curing catalyst to be blended is the amount necessary for curing the composition. Specifically, it is preferably 0.01 to 1,000 ppm (by mass) in terms of platinum metal relative to component (A), and more preferably 0.1 to 500 ppm. By setting the amount above the lower limit, sufficient curability can be obtained, and even if an amount exceeding the upper limit of the above range is blended, the curing speed of the resulting silicone composition does not significantly improve.

[0054] [Curing reaction inhibitor (hereinafter sometimes referred to as component (H))] When this composition hardens by an addition reaction (hydrosilylation reaction), it is preferable to include a hardening reaction inhibitor to adjust the hardening rate and improve handling. Preferably, the hardening reaction inhibitor contains acetylene compounds such as 2-methyl-3-butyne-2-ol, 2-phenyl-3-butyne-2-ol, and 1-ethynyl-1-cyclohexanol; en-yne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; and other hardening reaction inhibitors such as hydrazine compounds, phosphine compounds, and mercaptan compounds.

[0055] The amount of curing reaction inhibitor to be included is not limited, but 0.0001 to 1.0% by mass relative to the total composition is preferred. Setting the amount above the lower limit of the above range further improves the workability of the resulting composition. On the other hand, setting the amount below the upper limit of the above range prevents the curing rate of the resulting composition from becoming significantly slower.

[0056] [Organic peroxide curing silicone composition] In the case of organic peroxide-curable silicone compositions, (A) component is, (A-II) An organopolysiloxane having an alkenyl group bonded to a silicon atom, represented by the above formula (I-1), moreover, (II-2) Organic peroxides Examples include those that include:

[0057] (A-II) The preferred range of the organopolysiloxane having an alkenyl group bonded to a silicon atom, represented by formula (I-1) above, is the same as described above.

[0058] (II-2) Organic peroxides Examples of organic peroxides include benzoyl peroxide, dicumyl peroxide, 2,5-dimethylbis(2,5-t-butylperoxy)hexane, di-t-butyl peroxide, and t-butyl perbenzoate. The amount of organic peroxide to be added is the amount necessary for the curing of the composition, and specifically, 0.1 to 5 parts by mass per 100 parts by weight of the organopolysiloxane of component (A) is preferred. This is because the composition hardens more sufficiently when the amount of this component is above the lower limit of the above range. On the other hand, adding an amount exceeding the upper limit of the above range does not significantly improve the curing speed of the resulting silicone composition and may even cause voids.

[0059] [Condensation reaction curable silicone composition] In the case of a condensation reaction curable silicone composition, (A) Component is, (A-III) General formula below (III-1) [ka] (In the formula, R 4 (i is an unsubstituted or substituted monovalent hydrocarbon group that does not have an aliphatic unsaturated bond, and i is an integer of 1 or more.) As shown, it is an organopolysiloxane in which both ends are sealed with hydroxyl groups, moreover, (III-2) General formula below (III-2) R 5j -SiX (4-j) (III-2) (In the formula, R 5 (Independently, is an unsubstituted or substituted monovalent hydrocarbon group without an aliphatic unsaturated bond, X is a hydrolyzable group, and j is 0 or 1.) One or more selected from the silane compounds shown, their (partial) hydrolysates and (partial) hydrolysate condensates, and (III-3) Condensation reaction curing catalyst Examples include those that include:

[0060] (A-III) is given by the following general formula (III-1) [ka] (In the formula, R 4 (i is an unsubstituted or substituted monovalent hydrocarbon group that does not have an aliphatic unsaturated bond, and i is an integer of 1 or more.) It is an organopolysiloxane represented as such, with both ends sealed by hydroxyl groups, and can be used alone or in combination of two or more types.

[0061] R 4 R is independently an unsubstituted or substituted monovalent hydrocarbon group that does not have an aliphatic unsaturated bond, for example, the above R 1 Examples include linear alkyl groups, branched alkyl groups, cyclic alkyl groups, alkenyl groups, aryl groups, and aralkyl groups. Among these, unsubstituted, halogen-substituted, or cyano-substituted alkyl groups with 1 to 5 carbon atoms or aryl groups with 6 to 8 carbon atoms are preferred.

[0062] The molecular structure of such organopolysiloxanes is not limited, and examples of structures similar to those described above are given, with linear and partially branched linear structures being preferred.

[0063] (III-2) The component is given by the following general formula (III-2) R 5 j -SiX (4-j) (III-2) (In the formula, R 5(Independently, is an unsubstituted or substituted monovalent hydrocarbon group without an aliphatic unsaturated bond, X is a hydrolyzable group, and j is 0 or 1.) It is one or more selected from silane compounds represented by , their (partial) hydrolysates and (partial) hydrolysate condensates, and can be used alone or in combination of two or more.

[0064] R 5 R is independently an unsubstituted or substituted monovalent hydrocarbon group that does not have an aliphatic unsaturated bond, for example, the above R 1 Similar groups can be cited. Examples include linear alkyl groups, branched alkyl groups, cyclic alkyl groups, alkenyl groups, aryl groups, and aralkyl groups, as described above. Among these, unsubstituted, halogen-substituted, or cyano-substituted alkyl groups and phenyl groups having 1 to 3 carbon atoms are preferred. Examples of hydrolyzable groups of X include alkoxy groups such as methoxy, ethoxy, and propoxy groups; alkenoxy groups such as vinyloxy, propenoxy, isopropenoxy, and 1-ethyl-2-methylvinyloxy groups; alkoxyalkoxy groups such as methoxyethoxy, ethoxyethoxy, and methoxypropoxy groups; acyloxy groups such as acetoxy and octanoyloxy groups; ketoxime groups such as dimethylketoxime and methylethylketoxime groups; amino groups such as dimethylamino, diethylamino, and butylamino groups; aminooxy groups such as dimethylaminooxy and diethylaminooxy groups; and amide groups. (III-2) Examples of components include methyltriethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and ethyl orthosilicate.

[0065] (III-2) The amount of component (III-2) when included is the amount necessary for the curing of the composition, and specifically, 0.01 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass, per 100 parts by mass of component (A). By setting the amount of silane or its partial hydrolysate above the lower limit of the above range, the storage stability of the resulting composition becomes more stable and the adhesiveness is further improved. By setting it below the upper limit of the above range, it is possible to suppress the curing of the resulting composition from becoming significantly slower.

[0066] (III-3) Condensation reaction curing catalyst The condensation reaction curing catalyst is an optional component and is not essential when using a silane having hydrolyzable groups such as an aminooxy group, amino group, or ketoxime group as the curing agent. Examples of such condensation reaction catalysts include: organotitanium esters such as tetrabutyl titanate and tetraisopropyl titanate; organotitanium chelate compounds such as diisopropoxybis(acetylacetate)titanium and diisopropoxybis(ethylacetate)titanium; organoaluminum compounds such as aluminum tris(acetylacetonate) and aluminum tris(ethylacetate); organoaluminum compounds such as zirconium tetra(acetylacetonate) and zirconium tetrabutyrate; dibutyltin dioctoate, dibutyl Examples include organotin compounds such as tin dilaurate and butyltin-2-ethylhexoate; metal salts of organic carboxylic acids such as tin naphthenate, tin oleate, tin butyrate, cobalt naphthenate, and zinc stearate; amine compounds such as hexylamine and dodecylamine phosphate, and their salts; quaternary ammonium salts such as benzyltriethylammonium acetate; lower fatty acid salts of alkali metals such as potassium acetate and lithium nitrate; dialkylhydroxylamines such as dimethylhydroxylamine and diethylhydroxylamine; and organosilicon compounds containing guanidyl groups.

[0067] In this composition, when component (III-3) is included, the amount is arbitrary and should be sufficient for the curing of the composition. Specifically, 0.01 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass, are preferred per 100 parts by mass of component (A). This is because, if this catalyst is essential, setting the catalyst content above the lower limit of the above range allows the resulting composition to cure more thoroughly. On the other hand, setting it below the upper limit of the above range ensures greater storage stability of the resulting composition.

[0068] Furthermore, the composition may also contain, as long as it does not impair the objectives of the present invention, other optional components such as silane coupling agents such as vinyl silane coupling agents, epoxy silane coupling agents, and acrylic silane coupling agents; fillers such as zinc oxide, fumed silica, precipitated silica, and fumed titanium oxide; fillers whose surfaces have been hydrophobized with organosilicon compounds; adhesion promoters such as 3-glycidoxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane; and other pigments, dyes, fluorescent dyes, heat-resistant additives, flame retardants such as triazole compounds, and plasticizers. The amount of optional components can be 0.01 to 1.0% by mass of the total composition.

[0069] If the composition is curable, the method of curing it is not limited. Examples include leaving the composition at room temperature after molding, or heating the composition to 15-200°C, preferably 40-200°C, after molding. Furthermore, the properties of the silicone rubber obtained in this way are not limited, but examples include gel-like, low-hardness rubber-like, or high-hardness rubber-like.

[0070] [Manufacturing method] The composition of the present invention can be prepared by mixing predetermined amounts of each of the above components. For example, the process may include a step of mixing so that the volume ratio of component (B):(C) is 5:5 to 9.5:0.5, and components (A) to (E) and other optional components may be mixed.

[0071] [Thermally conductive silicone composition] The thermal conductivity of the thermally conductive silicone composition (cured product) is preferably 5.0 W / m·K or higher, more preferably 5.2 m·K or higher, and even more preferably 5.5 W / m·K or higher, according to the hot disk method in accordance with ISO 22007-2. There is no particular upper limit, and it may be higher, but considering the handling of the composition, 10.0 W / m·K or lower is preferred. The measurement temperature is 25°C. For measuring the thermal conductivity of the composition in this invention, for example, a device manufactured by Kyoto Electronics Ltd., product name "TPS 2500 S", can be used.

[0072] Furthermore, the viscosity of the thermally conductive silicone composition at 25°C is preferably 30 to 800 Pa·s, and more preferably 100 to 600 Pa·s, when measured using a spiral viscometer at a rotation speed of 10 rpm. The viscosity of the composition of the present invention can be measured using a spiral viscometer, for example, the Malcolm Type PC-10AA. The thermally conductive silicone composition of the present invention has excellent storage properties (viscosity stability) and thermal conductivity, and can also be expected to have insulating properties.

[0073] [Cured product] If the silicone composition is curable, a cured product can be obtained by curing it using the method described above, and a silicone elastomer molded product can be obtained. The properties of the silicone rubber obtained in this way are not limited, but examples include gel-like, low-hardness rubber-like, or high-hardness rubber-like. The cured thickness is preferably 150 μm or more. There is no particular upper limit, but considering the size of the heat-generating electronic component using this composition, 5 mm or less is preferred. The hardness of the cured product is preferably 15 to 85, and more preferably 20 to 80, using the method described in the examples. [Examples]

[0074] The present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0075] The components used are listed below. Note that Me represents a methyl group and Vi represents a vinyl group, and the bond order of the siloxane units is not considered. The rotational viscosity at 25°C was measured using a BM-type viscometer or a BH-type viscometer (manufactured by Tokyo Keiki Co., Ltd.), and the kinematic viscosity at 25°C was measured using an Ostwald viscometer. (A) component A-1: Dimethylpolysiloxane with a rotational viscosity (25°C) of 400 mPa·s, a specific gravity (25°C) of 0.98, and both ends sealed with dimethylvinylsilyl groups, with a Vi group content of 0.018 mol / 100g. A-2: KF-54 manufactured by Shin-Etsu Chemical Co., Ltd., with a specific gravity (25°C) of 1.07 and a kinematic viscosity (25°C) of 400 mmHg. 2 / s molecular chain with trimethylsiloxy groups sealed at both ends: dimethylsiloxane-diphenylsiloxane copolymer A-3: KF-50-1,000cs manufactured by Shin-Etsu Chemical Co., Ltd., with a specific gravity (25°C) of 1.00 and a kinematic viscosity (25°C) of 1,000 mm². 2 / s molecular chain with trimethylsiloxy groups sealed at both ends: dimethylsiloxane-diphenylsiloxane copolymer

[0076] (B) Component Spherical aluminum oxide (specific gravity 3.98) with the properties shown in the table below.

[0077] [Table 1]

[0078] (C) Component [Table 2]

[0079] (D) Component D-1: An organopolysiloxane represented by the following formula, with a specific gravity (25°C) of 0.97 and a kinematic viscosity (25°C) of 0.03 Pa·s. [ka]

[0080] (E) Component E-1: IXE-100 (manufactured by Toagosei Co., Ltd.), a cation exchange type ion trap agent with a bulk density of 0.52 (25°C) and supported with Zr element. E-2: IXEPLAS-A1 (manufactured by Toagosei Co., Ltd.), a dual ion-exchange type ion trap agent with a bulk density of 0.25 (25°C) and supported with Zr, Mg, and Al elements. e-3 (Comparative product): IXE-500 (manufactured by Toagosei Co., Ltd.), an anion exchange type ion trap agent with a bulk density of 0.73 (25°C) and supported with Bi element.

[0081] (F) component F-1: Represented by the following formula, with a specific gravity (at 25°C) of 0.97 and a kinematic viscosity (at 25°C) of 28 mm². 2 / s organohydrogenpolysiloxane [ka] F-2: Represented by the following formula, with a specific gravity (25°C) of 0.97 and a kinematic viscosity (25°C) of 17 mm². 2 / s organohydrogenpolysiloxane [ka]

[0082] (G) Component G-1: Chloroplatanic acid-1,3-divinyltetramethyldisiloxane complex with a specific gravity (25°C) of 1.00 and a platinum concentration of 1% by mass.

[0083] (H) Component H-1: Specific gravity (25°C) is 0.92, and it is a 50% toluene solution of 1-ethynyl-1-cyclohexanol.

[0084] [Examples 1-7, Comparative Examples 1-8] The above components (A) to (H) were mixed in the amounts shown in Table 1 as follows to obtain the composition. Specifically, components (A), (B), (C), and (D) were placed in the amounts shown in the table below into a 5-liter gate mixer (manufactured by Inoue Seisakusho Co., Ltd., product name: 5-liter planetary mixer) and degassed and heated and mixed at 150°C for 2 hours. After that, it was cooled to room temperature (25°C), component (G) was added and mixed at room temperature (25°C) until homogeneous, and then component (H) was added and mixed at room temperature (25°C) until homogeneous. Furthermore, components (E) and (F) were added and degassed and mixed at room temperature until homogeneous. The viscosity, initial hardness, hardness after degradation, and thermal conductivity of the addition-curing type thermal conductive silicone composition obtained in this way were evaluated by the method shown below. The results are shown in the table below.

[0085] [Viscosity evaluation] The initial viscosity of the thermally conductive silicone composition at 25°C is shown, measured using a Malcolm viscometer (Type PC-10AA, rotation speed 10 rpm).

[0086] [Initial hardness evaluation] A thermally conductive silicone composition was poured into a mold to achieve a cured thickness of 6 mm and cured at 100°C for 1 hour. Next, two 6 mm thick cured pieces were stacked and measured using an Asker C hardness tester.

[0087] [Hardness evaluation after acceleration] The thermally conductive silicone composition was accelerated at 40°C for 7 days. Then, the thermally conductive silicone composition was poured into a mold to achieve a cured thickness of 6 mm and cured at 100°C for 1 hour. Next, two 6 mm thick cured pieces were stacked and measured using an Asker C hardness tester. If the difference between the initial hardness and the hardness after accelerated degradation was 10 points or more, it was determined that curing delay had occurred, and therefore the shelf life of the composition could not be ensured.

[0088] [Thermal conductivity evaluation] The thermal conductivity of a 6mm cured sample of an addition-curing, one-component, thermally conductive silicone grease composition was measured at 25°C using a hot disk method thermophysical property measurement device TPA-501 manufactured by Kyoto Electronics Manufacturing Co., Ltd.

[0089] Table 3

[0090] Table 4

Claims

1. (A) Organopolysiloxanes (excluding component (D)), (B) Average sphericity of 0.8 or higher, with 30 hydroxyl groups / nm 2 The following are spherical aluminum oxide powders with an average particle size of 50 to 170 μm. (C) Spherical or irregularly shaped aluminum oxide powder with an average particle size of 0.1 to 5 μm. (D) The following formula (1) -SiR 11 (3-α) (OR 12 ) α (1) (In the formula, R 11 R is independently an unsubstituted or substituted monovalent hydrocarbon group. 12 (The group is independently selected from alkyl groups, alkoxyalkyl groups, alkenyl groups, and acyl groups, and α is 1, 2, or 3.) An organopolysiloxane having at least one silyl group represented by in one molecule and having a viscosity of 0.01 to 30 Pa·s at 25°C, and (E) An ion trapping agent selected from cation exchange type and dual ion exchange type, and on which one or more elements selected from Zr, Bi, Sb, Mg and Al are supported: 0.01 to 10 parts by mass per 100 parts by mass of component (A), A thermally conductive silicone composition comprising the above-mentioned (B) component and (C) component, wherein the volume ratio of the blending ratio ((B):(C)) is 5:5 to 9.5:0.

5.

2. The thermally conductive silicone composition according to claim 1, wherein the total amount of component (B) and component (C) is 80 to 87 volume percent of the thermally conductive silicone composition, the thermal conductivity of the thermally conductive silicone composition at 25°C is 5.0 W / m·K or higher in the hot disk method in accordance with ISO 22007-2, and the viscosity at 25°C is 30 to 800 Pa·s when measured by a spiral viscometer at a rotation speed of 10 rpm.

3. The thermally conductive silicone composition is an addition reaction curable silicone composition, (A) Component is (A - I) The following formula (I - 1) 【Chemistry 1】 (wherein, R 1 is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, and R 2 is an alkenyl group, and a1, a2, b1, b2, b3, c1, c2 and d are respectively a1≥0, a2≥0, b1≥0, b2≥0, b3≥0, c1≥0, c2≥0 and d≥0, and a2 + b2 + b3 + c2 > 0.) This is an organopolysiloxane having an alkenyl group bonded to a silicon atom, and further, (I-2) The following formula (I-2) 【Chemistry 2】 (In the formula, R 3 (E1, e2, f1, f2, f3, g1, g2, and h are independently unsubstituted or substituted monovalent hydrocarbon groups without aliphatic unsaturated bonds, and e1≧0, e2≧0, f1≧0, f2≧0, f3≧0, g1≧0, g2≧0, and h≧0, respectively, and e2+f2+f3+g2>0.) An organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms, and (I-3) Platinum group metal curing catalyst A thermally conductive silicone composition according to claim 1, comprising:

4. The thermally conductive silicone composition is an organic peroxide curable silicone composition, (A) Component is (A-II) An organopolysiloxane having an alkenyl group bonded to a silicon atom, represented by the above formula (I-1), moreover, (II-2) Organic peroxides A thermally conductive silicone composition according to claim 1, comprising:

5. The thermally conductive silicone composition is a condensation reaction curable silicone composition, (A) Organopolysiloxanes (A-III) General formula below (III-1) 【Transformation 3】 (In the formula, R 4 (i is an unsubstituted or substituted monovalent hydrocarbon group that does not have an aliphatic unsaturated bond, and i is an integer of 1 or more.) As shown, it is an organopolysiloxane in which both ends are sealed with hydroxyl groups, moreover, (III-2) The following general formula (III-2) R 5 j -SiX (4-j) (III-2) (In the formula, R 5 (Independently, are unsubstituted or substituted monovalent hydrocarbon groups that do not have an aliphatic unsaturated bond, X is a hydrolyzable group, and j is 0 or 1.) One or more selected from the silane compounds shown, their (partial) hydrolysates and (partial) hydrolyzates, and (III-3) Condensation reaction curing catalyst A thermally conductive silicone composition according to claim 1, comprising:

6. A cured product of a thermally conductive silicone composition according to any one of claims 1 to 5.

7. A cured product obtained by curing the thermally conductive silicone composition of claim 3 at 15 to 200°C by a hydrosilylation reaction.

8. A method for producing a thermally conductive silicone composition according to any one of claims 1 to 5, comprising the step of mixing the above-mentioned component (B) and component (C) such that the volume ratio of the blending ratio ((B):(C)) is 5:5 to 9.5:0.5.

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