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

Abstract

The present invention provides a thermally conductive silicone composition with excellent storage properties, insulating properties, and thermal conductivity. [Solution] (A) Organopolysiloxane, (B) Average sphericity of 0.8 or higher, with 30 hydroxyl groups / nm 2 The following describes spherical aluminum oxide powder with an average particle size of 8 μm or more and less than 50 μm, where the proportion of coarse particles between 96 and 150 μm is 0.1 to 30% by mass of the total (B) component. (C) Irregularly shaped aluminum oxide powder with an average particle size of 0.1 to 5 μm. (D) An organopolysiloxane containing at least one silyl group different from component (A) in one molecule, having a viscosity of 0.01 to 30 Pa·s at 25°C. (E) Ion trapping agent selected from cation exchange type and dual ion exchange type: 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.

Description

[Technical Field]

[0001] This invention relates to a thermally conductive silicone composition with excellent thermal conductivity, a cured product thereof, and a method for producing it. In particular, it relates to a highly thermally conductive silicone composition with excellent insulating properties and excellent thermal conductivity at high temperatures, which can be incorporated into electronic devices without damaging heat-generating electronic components such as power devices, transistors, thyristors, and CPUs (central processing units) when used as a heat dissipation material for electronic components. [Background technology]

[0002] For heat-generating electronic components such as power devices, transistors, thyristors, and CPUs, removing the heat generated during use is a critical issue. Conventionally, the common method of heat dissipation involves mounting the heat-generating electronic component to a heat sink fin or metal plate via an electrically insulating heat dissipation sheet, with the heat dissipation sheet typically being made of silicone resin with a thermally conductive filler dispersed within it.

[0003] In recent years, with the increasing integration of circuits within electronic components, the amount of heat generated has also increased. Thermal conductivity at high temperatures, such as above 100°C, and especially at 150°C, is becoming increasingly important, and materials with higher thermal conductivity than ever before are in demand. To improve the thermal conductivity of thermally conductive materials, the conventional method has been to incorporate highly thermally conductive fillers, such as aluminum oxide powder and aluminum nitride powder, into the matrix resin.

[0004] Therefore, in order to improve the thermal conductivity, in Japanese Patent Application Laid-Open No. 2013-056996, a method of a high thermal conductivity resin composition is disclosed, which uses spherical aluminum oxide powder defined by an average sphericity, a hydroxyl group amount, and an average particle diameter of 10 to 50 μm, and has an average particle diameter defined as 0.3 to 1 μm, with the blending ratio and volume ratio of each aluminum oxide defined. However, when the average particle diameter of the spherical aluminum oxide powder is at most 50 μm, there is no definition of the thermal conductivity at high temperatures, and there is a problem of insufficient thermal conductivity (Patent Document 1: Japanese Patent Application Laid-Open No. 2013-056996).

[0005] In addition, although a thermally conductive silicone composition using alumina powder with an average particle diameter of 0.1 to 100 μm has been proposed, no specific thermal conductivity or viscosity is defined. Furthermore, although a thermally conductive silicone composition defined by spherical alumina powder with an average particle diameter of 5 to 50 μm (excluding 5 μm) and spherical or irregularly shaped alumina powder with an average particle diameter of 0.1 to 5 μm, with the blending ratio and weight ratio of each aluminum oxide defined, has been proposed, there is no definition of the average sphericity and hydroxyl group amount of the spherical alumina with a large average particle diameter, and there is a problem of insufficiency in achieving high thermal conductivity at high temperatures (Patent Document 2: Japanese Patent No. 4646496).

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

[0007] In order to improve the storage stability of the hydrosilylation reaction system, it is effective to define a specific amount of Na ions generated from aluminum oxide, further perform surface treatment of aluminum oxide with a specific organohydrogenpolysiloxane in the manufacturing process of the composition, and use a cation exchange type and / or both ion exchange type ion trap agent. However, although there are examples of the average particle diameter of aluminum oxide, there is no description of the definition of average sphericity or the amount of hydroxyl groups. When aiming for further improvement in thermal conductivity, it was particularly difficult to achieve storage stability in the cured form of the hydrosilylation reaction system (Patent Document 4: Japanese Unexamined Patent Application Publication No. 2021-187874).

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0009] An object of the present invention has been made in view of the above circumstances, and it is an object to provide a thermally conductive silicone composition having excellent storage stability, insulation, and thermal conductivity without defining a specific amount of Na ions generated from aluminum oxide and further without performing surface treatment of aluminum oxide with a specific organohydrogenpolysiloxane in the manufacturing process of the composition. Another object is to provide a thermally conductive silicone composition suitable as a heat dissipation member for electronic components.

Means for Solving the Problems

[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 fruition 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 conditions apply to spherical aluminum oxide powder, with an average particle size of 8 μm or more and less than 50 μm, and a laser diffraction particle size distribution in which coarse particles of 96 to 150 μm account for 0.1 to 30% by mass of the total (B) component. (C) Irregularly shaped aluminum oxide powder with an average particle size of 0.1 to 5 μm. (D) General formula (1) below -SiR 11 (3-α) (OR 12 ) α (1) (In the formula, R 11 R is an unsubstituted or substituted monovalent hydrocarbon group, 12 (The group is independently selected from alkyl groups and acyloxy groups having 1 to 8 carbon atoms, and α is 1, 2, or 3.) An organopolysiloxane represented as such, containing at least one silyl group in one molecule that is different from component (A), and having a viscosity of 0.01 to 30 Pa·s at 25°C, (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 thermal conductive silicone composition according to claim 1, characterized in that the total amount of component (B) and component (C) is 65 to 80% by volume in the thermal conductive silicone composition, the thermal conductivity of the thermal conductive silicone composition at 25°C is 1.2 W / m·K or more and less than 5.5 W / (m·K) 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. A high thermal conductivity silicone composition according to 1 or 2, which is curable by addition reaction, organic peroxide, or condensation reaction. A cured product obtained by curing a high thermal conductivity silicone composition according to 4.1 or 2 at 15 to 200°C via a hydrosilylation reaction. 5. A method for producing a thermally conductive silicone composition according to any one of 1 to 3, 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. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a thermally conductive silicone composition that is excellent in terms of storage properties, insulation 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.

[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] (A) component's viscosity at 25 °C is not limited, but 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. By setting the viscosity to be not less than the above lower limit, the physical properties of the resulting cured product are further improved. On the other hand, by setting it to be not more than the upper limit of the above range, the handling workability of the silicone composition is further improved. In the present invention, the viscosity of each component may be expressed in terms of rotational viscosity and kinematic viscosity. The rotational viscosity is a value measured by a BM-type viscometer, BH-type viscometer or BS-type viscometer (these are, for example, manufactured by Tokyo Keiki Co., Ltd.) at 25 °C, and the rotor, rotation speed and rotation time are appropriately selected based on conventional methods according to the viscosity. The kinematic viscosity is a value measured using an Ostwald-type viscometer at 25 °C. Note that the viscosity of the entire composition is defined separately.

[0016] The amount of component (A) is preferably 1 to 15% by volume, more preferably 2 to 14% by volume in the composition.

[0017] [Component (B)] Component (B) is spherical aluminum oxide powder having an average sphericity of 0.8 or more, 30 hydroxyl groups / nm 2 or less, an average particle diameter of 8 μm or more and less than 50 μm, and the proportion of coarse particles of 96 to 150 μm in the laser diffraction particle size distribution is 0.1 to 30% by mass of the whole component (B). If the above range is satisfied, two or more types having different average particle diameters may be used in combination.

[0018] The crystal structure of the aluminum oxide powder may be either a single crystal or a polycrystal, but the crystal phase is preferably the α phase from the viewpoint of high thermal conductivity, and the specific gravity is preferably 3.7 (g / cm 3 ) or more. By setting the specific gravity to 3.7 or more, the proportion of voids and low crystal phases existing inside the particles can be reduced, and the thermal conductivity can be further increased. The particle size adjustment of the aluminum oxide powder can be performed 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, fluidity may decrease. If the average sphericity is less than 0.8, contact between particles becomes significant, the surface irregularities of the sheet become larger, the interfacial thermal resistance increases, and the thermal conductivity tends to worsen. There is no particular upper limit, but the closer to a sphere (average sphericity of 1), the better.

[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 8 μm or more and less than 50 μm, preferably 10 to 45 μm, and more preferably 13 to 42 μm. If the average particle diameter is less than 8 μm, there will be less contact between particles, which may lead to increased interparticle contact thermal resistance and poor thermal conductivity. If the average particle diameter is 50 μm or more, the surface irregularities of the sheet will increase, which may increase interfacial thermal resistance and poor thermal conductivity.

[0024] Component (B) has a laser diffraction particle size distribution where the proportion of coarse particles measuring 96-150 μm is 0.1-30 mass%, with 0.1-15 mass% being more preferable. By keeping it within this range, the desired thickness and high thermal conductivity can be achieved simultaneously. If the proportion of coarse particles measuring 96-150 μm is less than 0.1 mass%, the desired thickness of 100-150 μm cannot be achieved, and high thermal conductivity cannot be attained. If it is 30 mass% or more, the desired thickness of 100-150 μm can be achieved, but the packing performance of component (B) tends to deteriorate.

[0025] 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 absorbance is allowed to stabilize until it 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. Furthermore, the proportion of coarse particles 96μm or larger can also be easily determined from the overall particle size distribution (volume basis).

[0026] [(C) component] Component (C) is an amorphous aluminum oxide powder with an average particle size of 0.1 to 5 μm, and may be used alone or in combination of two or more types with different average particle sizes. The average particle size is 0.1 to 5 μm, with 0.5 to 2 μm being preferred. If the average particle size is less than 0.1 μm, contact between particles decreases, and the thermal conductivity tends to worsen due to an increase in interparticle contact thermal resistance. If it is greater than 5 μm, the surface irregularities of the sheet become larger, increasing the interfacial thermal resistance and tending to worsen the thermal conductivity. Furthermore, component (E), which will be described later, contains Na produced by component (C). + There is a risk that the ion capture rate will be reduced.

[0027] Furthermore, "irregular shape" refers to any shape that has not undergone intentional spheroidization treatment such as melting or granulation. In addition, while component (C) also exists in rounded and spherical shapes, spherical refers to those that are commercially available in a spherical shape after being treated with melting or granulation, while rounded refers to particles with few corners, resulting in a smooth, rounded state, and does not include spherical particles. These can be distinguished from irregular shapes.

[0028] The volume ratio of the above-mentioned components (B) and (C) ((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 will be poor. On the other hand, if it is greater than 9.5, the filler will be difficult to pack densely, and the thermal conductivity will tend to decrease.

[0029] The total amount of component (B) and component (C) is preferably 65 to 80% by volume, and more preferably 70 to 80% by volume, in the thermally conductive silicone composition. By making the total of component (B) and component (C) 60% by volume or more, the thermal conductivity of the composition is further improved, while if it is 80% by volume or less, filling with a thermally conductive filler is easy.

[0030] [(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 (where α is a group selected from alkyl groups and acyloxy groups having 1 to 8 carbon atoms, and α is 1, 2, or 3.) (D) is an organopolysiloxane that is represented as (A) and contains at least one silyl group in one molecule that is different from component (A), 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) makes it possible to obtain a composition with good handling and workability even when components (B) and (C) are included in large quantities.

[0031] An organopolysiloxane having at least one silyl group represented by the above general formula (1) in one molecule is the following general formula (2): [ka] (In the formula, R 11R is independently an unsubstituted or substituted monovalent hydrocarbon group. 12 (Each group is independently selected from alkoxy and acyloxy groups having 1 to 8 carbon atoms, α is 1, 2, or 3, and β is an integer from 2 to 100.) Examples of organopolysiloxanes represented by [formula] include [formula].

[0032] Of the above (1) and (2), R 11 Each 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.

[0033] R 12 R is independently selected from alkyl groups and acyloxy groups having 1 to 8 carbon atoms. 12 Examples of the groups include methoxy, ethoxy, and isopropoxy groups, with methoxy and ethoxy groups being preferred, and methoxy groups being more preferred. α is 1, 2, or 3, with 3 being more preferred.

[0034] (D) Suitable specific examples of organopolysiloxanes of component (D) are listed below. [ka] (In the formula, Me represents a methyl group.)

[0035] Component (D) has a viscosity of 0.01 to 30 Pa·s at 25°C, preferably 0.1 to 10 Pa·s. A viscosity of 0.01 Pa·s or higher suppresses oil bleeding and dripping from the resulting silicone composition. A viscosity of 30 Pa·s or lower improves the fluidity of the resulting silicone composition, making application easier. The viscosity of component (D) is measured at 25°C using a BM-type viscometer, BH-type viscometer, or BS-type viscometer (for example, manufactured by Tokyo Keiki Co., Ltd.). The rotor, rotation speed, and rotation time should be appropriately selected according to the viscosity based on conventional methods.

[0036] (D) As a surface treatment method for spherical alumina powder, a spray method using a fluid nozzle, a stirring method with shear force, a dry method using a ball mill or mixer, or a wet method using an aqueous or organic solvent system can be employed. When using the stirring method, it is important to do so to the extent that the spherical aluminum oxide powder is not destroyed. In the dry method, the system temperature or the drying temperature after treatment is appropriately determined according to the type of surface treatment agent, within a range in which the surface treatment agent does not volatilize or decompose, but 80 to 180°C is preferred.

[0037] 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. Furthermore, the amount of component (D) is preferably 1 to 25 volume%, and more preferably 2 to 20 volume%, of the total composition.

[0038] [(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.

[0039] Component (E) is supported with at least one element selected from Zr, Bi, Sb, Mg, and Al, preferably selected from Zr, Bi, Mg, and Al, and more preferably selected from Zr, Mg, and Al.

[0040] 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 more preferable that it is supported by hydrotalcites from the viewpoint of improving the storage properties of the composition of the present invention.

[0041] 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.

[0042] (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.

[0043] 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, more preferably 0.5 to 8 parts by mass, even more preferably 0.6 to 5 parts by mass, and particularly preferably 0.7 to 3 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, there is a risk that appropriate curability cannot be obtained.

[0044] [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.

[0045] [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(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.) Organohydrogenpolysiloxanes having hydrogen atoms bonded to silicon atoms, and (I-3) Platinum group metal curing catalyst Examples include those that include:

[0046] [(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.

[0047] In the above equation (I-1), R 1These 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.

[0048] 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.

[0049] 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.

[0050] 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 / 2 Examples 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.

[0051] [(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 (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.) 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.

[0052] R 3 R is independently an unsubstituted or substituted monovalent hydrocarbon group that does not have an aliphatic unsaturated bond, and R in formula (I-1) above 1 Similar 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.

[0053] 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.

[0054] 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.

[0055] [(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.

[0056] 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.

[0057] [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.

[0058] 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.

[0059] [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:

[0060] (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.

[0061] (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.

[0062] [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 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.) 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:

[0063] (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.

[0064] 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.

[0065] 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.

[0066] (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.) One or more silane compounds selected from those represented by , their (partial) hydrolysates, and (partial) hydrolyzed condensates, which can be used alone or in combination of two or more.

[0067] 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 1Similar 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.

[0068] (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.

[0069] (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.

[0070] 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.

[0071] Furthermore, this composition may contain a silane coupling agent. Examples of silane coupling agents include vinyl-based silane coupling agents, epoxy-based silane coupling agents, acrylic-based silane coupling agents, and long-chain alkyl-based silane coupling agents, with decyltrimethoxysilane, a long-chain silane coupling agent, being preferred. The content of the silane coupling agent is preferably 0.1 to 5 parts by mass per 100 parts by mass of spherical aluminum oxide powder. If it is 0.1 parts by mass or more, it is a processing amount that can exhibit an effect as a surface treatment agent for (B) spherical aluminum oxide, and if it is 5 parts by mass or less, it is an economical processing amount for (B) spherical aluminum oxide.

[0072] Furthermore, the composition may also contain, as long as it does not impair the objectives of the present invention, other optional components such as 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 above components are preferably present in an amount of 0.1 to 10.0% by mass of the total composition, and more preferably in an amount of 0.5 to 5.0% by mass.

[0073] If the composition is curable, the method of curing it is not limited. For example, the composition may be left at room temperature (20-25°C) after molding, or heated to 40-200°C after molding. In particular, it is preferable that the composition is addition-curable and cured at 15-200°C by a hydrosilylation reaction. The curing time is not particularly limited and can be appropriately selected depending on the purpose, but 30 minutes to 24 hours is preferred. 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.

[0074] [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.

[0075] [Thermally conductive silicone composition] The thermal conductivity of the thermally conductive silicone composition (cured product) is preferably 1.2 W / (m·K) or higher, more preferably 1.5 W / (m·K) or higher, and even more preferably 1.8 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, it is preferably less than 5.5 W / (m·K), preferably less than 5.2 W / (m·K), and more preferably less than 5.0 W / (m·K). 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.

[0076] 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.

[0077] [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]

[0078] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0079] 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.

[0080] First, the following components were prepared. In the formula, Me represents a methyl group. (A) component A-1: Kinematic viscosity (25℃) is 400 mm 2 Dimethylpolysiloxane has a viscosity of / s, a specific gravity (25°C) of 0.98, is capped at both ends with dimethylvinylsilyl groups, and has a Vi group content of 0.018 mol / 100 g. 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

[0081] (B) Component Spherical aluminum oxide (specific gravity 3.98) with the properties shown in the table below.

[0082] [Table 1] The coarse particle content shown here refers to the proportion of coarse particles between 96 and 150 μm in size relative to the entire particle size distribution obtained by laser diffraction-type particle size distribution analysis.

[0083] (C) Component Irregularly shaped aluminum oxide powder with the properties shown in the table below (specific gravity: 3.98)

[0084] [Table 2]

[0085] (D) Component D-1: Represented by the following formula, with a specific gravity (25°C) of 0.97 and a kinematic viscosity (25°C) of 0.03 mm³. 2 / s organopolysiloxane

[0086] [ka]

[0087] (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.

[0088] (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]

[0089] 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]

[0090] (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.

[0091] (H) Component H-1: Specific gravity (25°C) is 0.92, and it is a 50% toluene solution of 1-ethynyl-1-cyclohexanol.

[0092] [Examples, Comparative Examples] 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 Table 1 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, 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 composition obtained in this way were evaluated by the method shown below. The results are shown in the table below.

[0093] [Viscosity evaluation] The initial viscosity of the composition is shown as the value at 25°C, and was measured using a Malcolm viscometer (Type PC-10AA, rotation speed 10 rpm).

[0094] [Initial hardness evaluation] The 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.

[0095] [Hardness evaluation after acceleration] The composition was accelerated at 40°C for 7 days. Then, the 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 degradation was 10 points or more, it was determined that curing delay had occurred and the composition could not be stored properly.

[0096] [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.

[0097] [Table 3]

[0098] [Table 4]

[0099] [Table 5]

[0100] [Table 6]

Claims

1. (A) Organopolysiloxanes (excluding component (D)), (B) Average sphericity of 0.8 or higher, with 30 hydroxyl groups / nm 2 The spherical aluminum oxide powder is as follows: the average particle size is 8 μm or more and less than 50 μm, and the proportion of coarse particles measuring 96 to 150 μm in the laser diffraction particle size distribution is 0.1 to 30% by mass of the total (B) component. (C) Irregularly shaped aluminum oxide powder with an average particle size of 0.1 to 5 μm. (D) General formula (1) -SiR 11 (3-α) (OR 12 ) α (1) (In the formula, R 11 R is an unsubstituted or substituted monovalent hydrocarbon group, 12 (The group is independently selected from alkyl groups and acyloxy groups having 1 to 8 carbon atoms, and α is 1, 2, or 3.) An organopolysiloxane represented as such, containing at least one silyl group in one molecule that is different from component (A), and having a viscosity of 0.01 to 30 Pa·s at 25°C, (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, characterized in that the total amount of component (B) and component (C) is 65 to 80% by volume in the thermally conductive silicone composition, the thermal conductivity of the thermally conductive silicone composition at 25°C is 1.2 W / m·K or more and less than 5.5 W / (m·K) 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 high thermal conductivity silicone composition according to claim 1, which is curable by addition reaction, organic peroxide, or condensation reaction.

4. A high thermal conductivity silicone composition according to claim 1, wherein the composition is curable by addition reaction, and the cured product is cured at 15 to 200°C by a hydrosilylation reaction.

5. A method for producing a thermally conductive silicone composition according to any one of claims 1 to 3, 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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