TW201906934A - Thermally conductive siloxane composition - Google Patents

Abstract

This thermally-conductive silicone composition exhibits, after being cured, a small increase in hardness when being aged at a high temperature, and also any decrease in curing speed is constrained, wherein the composition contains (A) an organopolysiloxane having at least two alkenyl groups per molecule, and having a kinematic viscosity of 10-100,000 mm2/s at 25 DEG C, (B) a hydrolyzable methyl polysiloxane having three functional groups at one terminal thereof, (C) a thermally-conductive filler having a thermal conductivity of 10 W/m·DEG C or higher, (D) an organohydrogenpolysiloxane having hydrogen atoms bonded directly to at least two silicon atoms per molecule, (E) a catalyst selected from the group consisting of platinum and platinum compounds, (F) a specific amount of a triazole compound, and (G) a specific amount of an isocyanate compound.

Description

Thermally conductive silicone composition

The present invention relates to a thermally conductive silicone composition that does not increase the hardness after curing even if it is exposed to high temperature for a long time, and does not reduce the initial curing rate.

It is well known that electronic components such as LSI and IC wafers generate heat when they are used, and their performance is degraded. The solution is to use various heat release technologies. For example, by arranging a cooling member such as a water tank near the heat generating part, the two are closely joined to efficiently conduct heat to the cooling member to cool the heat generation, and it is known that the heat generating part can efficiently release heat. However, there is a gap between the heat generating member and the cooling member, and because of the low thermal conductivity of the air, the heat cannot be efficiently transferred, so the temperature of the heat generating member cannot be sufficiently reduced. In order to prevent this kind of phenomenon and prevent the air between the heat generating member and the cooling member, a heat dissipation material, a heat dissipation sheet, or a heat dissipation grease with good thermal conductivity and followability with the surface of the component have been used (Japanese Patent No. 2938428, Japan Patent No. 2938429, Japanese Patent No. 3952184: Patent Documents 1 to 3). Among them, since the exothermic grease can be used in a thinner thickness during mounting, it can exert higher performance from the viewpoint of thermal resistance.

There are some types of exothermic grease that are held between the components and then heated and hardened. The exothermic grease after heating and hardening will be reheated when the component moves, so the hardness will be increased during use. Increasing the hardness will cause the material to lose its flexibility, and it may not be able to track the curvature of the activity. If it cannot be traced, a gap will be formed between the component and the heat-dissipating grease, and the heat-dissipating properties will be deteriorated.

It is also known that the addition of triazole compounds to silicone rubber can reduce compression set. When the compression set is reduced, it can be expected to suppress the increase in hardness during high-temperature aging. However, when only the triazole-based compound is added, there is a problem that the curing rate is reduced when heated. When the curing speed of the exothermic grease is reduced, the material will generate a small amount of gas before curing, and expand after heating, and then holes (voids) will occur in the material due to curing, so there is a problem of reducing the heat release performance. [Prior Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent No. 2938428 Patent Document 2: Japanese Patent No. 2938429 Patent Document 3: Japanese Patent No. 3952184

[Problems to be solved by the invention]

In view of the foregoing, an object of the present invention is to provide a thermally conductive siloxane composition that reduces the increase in hardness during high-temperature aging after curing while suppressing the decrease in curing rate. [Method of solving the problem]

In order to achieve the above purpose, the present inventors have carefully examined and found that each contains (A) an organic polysilicon having at least 2 alkenyl groups in a molecule and a dynamic viscosity of 25 to 10 to 100,000 mm ² / s at a specific ratio. Oxane (B) The following general formula (1) (In the formula, R ¹ is an alkyl group having 1 to 6 carbon atoms, and a is a positive number from 5 to 100) The single-terminal trifunctional hydrolyzable methyl polysiloxane (C) represented by the formula has 10 W / m The thermal conductivity of the thermal conductivity filler (D) contains at least 2 hydrogen atoms directly bonded to silicon atoms in one molecule of an organic hydrogenated polysiloxane (E) selected from the group consisting of platinum and platinum compounds Medium (F) triazole compound (G) isocyanate compound thermally conductive silicone composition (siloxane grease composition) can reduce the increase in hardness during high temperature aging after curing, while suppressing the decrease in curing rate, and complete this invention.

Therefore, the present invention provides the following thermally conductive silicone composition. [1] A thermally conductive silicone composition containing (A) an organic polysiloxane containing at least 2 alkenyl groups in one molecule and a dynamic viscosity of 25 to 10 to 100,000 mm ² / s (B ) The following general formula (1) (In the formula, R ¹ is an alkyl group having 1 to 6 carbon atoms, and a is a positive number of 5 to 100) The single-terminal trifunctional hydrolyzable methyl polysiloxane represented by: relative to 100 parts by mass of (A) component 10 to 150 parts by mass (C) Thermally conductive filler with a thermal conductivity of 10 W / m‧ ° C or higher: 500 to 3,000 parts by mass (D) relative to 100 parts by mass of the total of (A) and (B) components Organic hydrogenated polysiloxane containing at least 2 hydrogen atoms directly bonded to silicon atoms in one molecule: {(D) component Si-H group number} / {(A) component alkenyl group number } Amount of 0.5 ~ 1.5 (E) Catalyst selected from the group consisting of platinum and platinum compounds: Amount of platinum atoms relative to (A) component in an amount of 0.1 ~ 500ppm (F) Triazole compounds: 1 mole of platinum atom relative to (E) component is 2 to 1,000 moles (G) isocyanate compound: 0.1 mole to 10 mole relative to 1 mole of triazole compound of (F) component. [2] The thermally conductive silicone composition as described in [1], wherein the component (F) is composed of 1,2,3-triazole, 1,2,4-triazole and derivatives of these The selected thing. [3] The thermally conductive silicone composition described in [2], wherein the component (F) is benzotriazole. [4] The thermally conductive silicone composition as described in any one of [1] to [3], wherein the component (G) is composed of an alkyl isocyanate-based compound, an aryl isocyanate-based compound, and an isocyanate silane-based compound Selected. [5] The thermally conductive silicone composition as described in [4], wherein the component (G) is the following formula (2) (In the formula, R ² is an alkyl group or a trialkylsilyl group, and b is an integer of 1 to 6). [6] The thermally conductive siloxane composition as described in any one of [1] to [5], which further contains (H) of acetylene compounds, nitrogen compounds, organic phosphorus compounds, oxime compounds and organic chlorine compounds Selected reaction inhibitor: 0.1% to 5% by mass relative to component (A). [Effect of invention]

In the thermally conductive silicone composition of the present invention, by adding a specific amount of triazole-based compound and isocyanate-based compound, the increase in hardness of the cured product during high-temperature aging can be suppressed, and the decrease in curing rate can be suppressed.

[(A) component] The organic polysiloxane constituting the (A) component of the present invention has at least 2 in one molecule, preferably 2 to 10, more preferably 2 to 5 directly bonded to silicon The atomic alkenyl group may be linear or branched, or a mixture of two or more of these with different viscosities.

Alkenyl groups such as vinyl, allyl, 1-butenyl, 1-hexenyl and the like having 2 to 6 carbon atoms are preferably vinyl in terms of ease of synthesis and cost. The remaining organic groups bonded to the silicon atom are preferably unsubstituted or substituted C 1-12, especially C 1-6 monovalent hydrocarbon groups without aliphatic unsaturated bonds, such as methyl, ethyl Alkyl, propyl, butyl, hexyl, dodecyl and other alkyl groups, phenyl and other aryl groups, 2-phenylethyl, 2-phenylpropyl and other aralkyl groups, such as chloromethyl Group, 3,3,3-trifluoropropyl and other halogen-substituted hydrocarbon groups. These are preferably methyl in terms of ease of synthesis and cost. The alkenyl group bonded to the silicon atom may exist at the end of the molecular chain of the organic polysiloxane or at any one of the way, but it is preferably at least at the end.

(A) The component has a kinematic viscosity at 25 ° C measured by an austeniometer in the range of 10 to 100,000 mm ² / s, preferably in the range of 100 to 50,000 mm ² / s, more preferably 100 to 1,000 mm ² / s. When the dynamic viscosity is less than 10mm ² / s, the oil spill of the composition will be extremely deteriorated and the reliability will be deteriorated. When it exceeds 100,000 mm ² / s, the viscosity of the composition will be increased, and it will become a lack of ductility.

(A) Components such as dimethylpolysiloxane which is chain-sealed at both ends of the molecular chain by dimethylvinylsiloxy, the chain-end is chain-sealed by dimethylvinylsiloxy and the other end of the molecular chain Dimethylpolysiloxane-methylvinylpolysiloxane copolymer capped with trimethylsiloxy, and dimethylsiloxane capped with trimethylsiloxy on both ends of the molecular chain- Methylvinylsiloxane copolymer, methylvinylpolysiloxane with molecular chains capped with trimethylsiloxy groups at both ends, and dimethylvinylsiloxane chain capped with dimethylvinylsilane groups at both ends Methylsiloxane-methylvinylsiloxane copolymer, etc., but not limited to these, and two or more of them can be mixed and used.

[(B) component] (B) component is the following general formula (1) (In the formula, R ¹ is a C 1-6 methyl, ethyl, propyl, butyl, hexyl and other alkyl groups, a is a positive number of 5 to 100) The single-terminal trifunctional hydrolyzable A represented by Based polysiloxane.

(B) When the a of the single-terminal trifunctional hydrolyzable methyl polysiloxane represented by the general formula (1) of the component is less than 5, the oil spillability of the composition will be extremely deteriorated, and the reliability will be deteriorated. At 100, the wettability will be insufficient, so it is a positive number from 5 to 100, preferably from 10 to 60.

When the added amount of the mono-terminal trifunctional hydrolyzable methyl polysiloxane is less than 10 parts by mass relative to 100 parts by mass of the component (A), sufficient wettability cannot be exerted, and if it exceeds 150 parts by mass, it will intensify The oil spill property deteriorates the reliability, so it is 10 to 150 parts by mass, preferably 20 to 140 parts by mass.

[Component (C)] The component (C) is a thermally conductive filler having a thermal conductivity of 10 W / m‧ ° C. or higher. The thermally conductive filler of component (C) has a thermal conductivity of 10 W / m‧ ° C or higher, preferably 15W / m‧ ° C or higher. When the thermal conductivity of the filler is less than 10W / m‧ ℃, the thermal conductivity of the thermally conductive silicone composition will be reduced. Such thermally conductive fillers are, for example, aluminum powder, copper powder, silver powder, iron powder, nickel powder, gold powder, tin powder, metal silicon powder, aluminum nitride powder, boron nitride powder, alumina powder, diamond powder, Carbon powder, indium powder, gallium powder, zinc oxide powder, etc., may be any filler when they have a filler of 10 W / m‧ ° C or higher, or they may be a mixture of one or two or more.

(C) The average particle size of the component is preferably in the range of 0.1 to 100 μm, and more preferably in the range of 0.1 to 90 μm, more preferably in the range of 0.1 to 20 μm. When the average particle size is less than 0.1 μm, the resulting composition cannot become a paste-like system lacking in stretchability. When it is greater than 100 μm, the thermal resistance of the exothermic grease is increased and the performance is reduced. In addition, the average particle diameter of the present invention can be measured by Nikkiso Co., Ltd. microrail MT330OEX, which is the volume-based average diameter of volume ratio. The shape of the (C) component can be either indefinite or spherical.

(C) When the filling amount of the component is less than 500 parts by mass relative to the total of 100 parts by mass of the (A) component and (B) component, the thermal conductivity of the composition will be reduced, and when it exceeds 3,000 parts by mass, the viscosity of the composition will be increased. It becomes a lack of stretchability, so it is in the range of 500 to 3,000 parts by mass, preferably in the range of 500 to 2,800 parts by mass, and more preferably in the range of 500 to 2,500 parts by mass.

[(D) component] The organic hydrogenated polysiloxane of (D) component needs to have at least 2 in one molecule, preferably 2-50, more preferably 2 ~ 30 hydrogen atoms (Si-H groups) directly bonded to silicon atoms. In addition, the Si-H group may be located at the end of the molecular chain, or on either side of the molecular chain, or on both sides.

The remaining organic groups other than the Si-H group bonded to the silicon atom are preferably non-substituted or substituted C 1-12 carbon atoms, especially C 1-6 monovalent hydrocarbon groups without aliphatic unsaturated bonds, Specific examples include methyl, ethyl, propyl, butyl, hexyl, dodecyl and other alkyl groups, phenyl and other aryl groups, 2-phenylethyl, 2-phenylpropyl and other aralkyl groups , Chloromethyl, 3,3,3-trifluoropropyl and other halogen-substituted hydrocarbon groups, such as 2-glycidoxyethyl, 3-glycidoxypropyl, 4-glycidoxypropyl Epoxy-substituted hydrocarbon groups such as butyl and the like.

This type of organic hydrogenated polysiloxane with Si-H group can be any of linear, branched and cyclic, or a mixture of these. In addition, the number of silicon atoms in the organic hydrogenated polysiloxane is 10 to 250; particularly preferably 10 to 200. The organic hydrogenated polysiloxane can be used alone or in combination of two or more.

(D) Components such as a copolymer formed by (CH ₃ ) ₂ HSiO _1/2 units and (CH ₃ ) ₂ SiO units, and (CH ₃ ) ₂ HSiO _1/2 units and (CH ₃ ) ₃ SiO ₁ Copolymer formed by _{/ 2} units and (CH ₃ ) ₂ SiO units, copolymer formed by (CH ₃ ) ₃ SiO _1/2 units and (CH ₃ ) ₂ SiO units and (CH ₃ ) HSiO units, by (CH ₃ ) ₂ HSiO _1/2 unit and (CH ₃ ) ₃ SiO _1/2 unit and (CH ₃ ) ₂ copolymer of SiO unit and (CH ₃ ) HSiO unit, (CH ₃ ) ₃ SiO ₁ Copolymer formed by _{/ 2} units and (CH ₃ ) HSiO units, copolymer formed by (CH ₃ ) ₂ HSiO _1/2 units and (CH ₃ ) ₂ SiO units and (CH ₃ ) HSiO, formed by (CH ₃ ) ₃ SiO _1/2 unit and (CH ₃ ) ₂ SiO _1/2 unit and (CH ₃ ) HSiO unit formed by the copolymer formed by (CH ₃ ) HSiO unit cyclic copolymer formed by (CH ₃ ) A cyclic copolymer formed by HSiO units and (CH ₃ ) ₂ SiO units, etc., but not limited to these.

(D) When the added amount of the component is {the number of Si-H groups of the (D) component} / {the number of alkenyl groups of the (A) component} is less than 0.5, the composition will not be fully reticulated and the oil spill will occur If the pump is disabled, if it is greater than 1.5, the crosslink density will be excessively increased and peeled off in the reliability test, so it is in the range of 0.5 to 1.5, preferably 0.7 to 1.3.

[Component (E)] The catalyst selected from platinum and platinum compounds for component (E) is to promote the addition reaction between the alkenyl group in (A) component and the Si-H group in (D) component. Promotes ingredients. The component (E) includes, for example, platinum monomers, chloroplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, platinum coordination compounds, and the like.

(E) The added amount of the component relative to the mass of the (A) component is that when the platinum atom is less than 0.1 ppm, it cannot be effectively used as a catalyst, and even if it exceeds 500 ppm, the effect cannot be increased and it is not conducive to the economy, so it is 0.1 ~ The range of 500 ppm is preferably 0.1 to 400 ppm.

[Component (F)] The triazole compound of component (F) can be added to the composition in a specific addition amount together with the component (G) to be described later to suppress the hardening rate of the thermally conductive silicone composition and after curing The hardness increases during high temperature aging.

(F) The triazole compounds of the component are, for example, 1,2,3-triazole, 1,2,4-triazole and derivatives of these. Specific 1,2,3-triazole derivatives such as benzotriazole, 4-hydroxy-1,2,3-triazole, 1,2,3-triazole-4-aldehyde, 4-cyano- 1,2,3-triazole etc. 1,2,4-Triazole derivatives such as 5-amino-3-methyl-1,2,4-triazole, 3-mercapto-1,2,4-triazole and the like. Among them, benzotriazole, 1,2,3-triazole and 1,2,4-triazole are preferable, and benzotriazole is the most preferable. These can be used alone or in combination of two or more.

The added amount of the component (F) is 2 to 1,000 mols, preferably 2 to 800 mols, more preferably 2 to 500 mols with respect to 1 mol of platinum atoms of the component (E). When the addition amount is less than 2 moles, the hardness increase cannot be sufficiently suppressed, and when it is more than 1,000 moles, the hardening speed is slowed down.

[Component (G)] The isocyanate compound of component (G) can be added to the composition in a specific addition amount together with the aforementioned (F) component to suppress the decrease in the curing rate of the thermally conductive silicone composition, and after curing The hardness increases during high temperature aging.

(G) The isocyanate-based compound of the component is, for example, alkyl isocyanate-based compounds such as methyl isocyanate, butyl isocyanate, octyl isocyanate, and aryl isocyanate-based compounds such as phenyl isocyanate and tolyl isocyanate. 2) As shown, isocyanate silane compounds containing isocyanate groups and silane groups. (In the formula, R ² is an alkyl group or a trialkylsilyl group, and b is an integer of 1 to 6).

In this case, the alkyl group of R ² is a carbon number 1-4, particularly preferably methyl and ethyl, and the alkyl group of trialkylsilyl is also a carbon number 1-4, particularly preferably methyl and ethyl The base is preferably trimethylsilyl or triethylsilyl.

Among these, octyl isocyanate, 3-isocyanate propyl trimethoxysilane, 3-isocyanate propyl triethoxy silane, and 3-isocyanate propyl tri (trimethylsiloxy) silane are the best. These can be used alone or in combination of two or more.

The added amount of the (G) component is 0.1 to 10 mols relative to 1 mol of the (F) component, preferably 0.5 to 5 mols, and more preferably 0.5 to 2 mols. When the addition amount is less than 0.1 moles, the hardening speed will be reduced, and if it is more than 10 moles, the increase in hardness after aging cannot be sufficiently suppressed.

[(H) component] In order to suppress the catalytic activity of the (E) component, the (H) component of the thermally conductive silicone composition of the present invention may additionally be added as a reaction inhibitor. (H) The reaction inhibitor of the component is a substance that can inhibit the addition reaction of silicose at room temperature, prolong the storage life and pot life. As the reaction inhibitor, known ones can be used, and acetylene compounds, various nitrogen compounds, organic phosphorus compounds, oxime compounds, organic chlorine compounds, and the like can be used.

When the (H) component is added in an amount less than 0.1% by mass relative to the (A) component, sufficient storage life, pot life, and a curing rate of more than 5% by mass will be reduced, so 0.1 to 5% by mass is preferred % Range, especially good is 0.1 ~ 4 mass% range. In order to have good dispersibility with respect to the thermally conductive silicone composition, it can be diluted with a solvent such as toluene before use.

In addition to the above-mentioned components (A) to (H), the thermally conductive silicone composition of the present invention may be added with an antioxidant or the like as necessary to prevent deterioration.

When manufacturing the thermally conductive silicone composition of the present invention, a triple mixer, a double mixer, a planetary mixer (all registered trademarks of Inoue Manufacturing Co., Ltd. mixer), and a super mixer (Mizuho Industries ( Co., Ltd. (registered trademarks of mixers), fast double dispersion mixers (registered trademarks of special machine chemical industry (shares) mixers) and other mixers are manufactured by mixing (A) ~ (H) components.

The obtained thermally conductive silicone composition has an absolute viscosity at 25 ° C measured by a rotary viscometer of 5 to 2,000 Pa‧s, particularly preferably 10 to 900 Pa‧s.

In addition, the resulting thermally conductive silicone composition can be hardened by heating at 80 to 180 ° C, especially 90 to 170 ° C for 30 to 150 minutes, especially 30 to 140 minutes.

The thermally conductive silicone composition of the present invention can suppress a decrease in the curing rate, and the cured product of the composition can suppress the increase in hardness during high-temperature aging. Therefore, it is suitable for use as a thermally conductive material for heating elements such as semiconductor wafers and cooling members. [Example]

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

The test concerning the effect of the present invention was carried out as follows.

[Viscosity] The absolute viscosity of the thermally conductive silicone composition is measured at 25 ° C using a Markov viscometer (type PC-1TL; manufactured by Marco Co., Ltd.).

[Thermal conductivity] Flow each component into a mold with a thickness of 3 cm, cover it with a plastic film for kitchen, and measure at 25 ° C with Model QTM-500 manufactured by Kyoto Electronics Industry Co., Ltd.

[Evaluation of hardening rate] Coat a 2mm thick thermally conductive silicone composition between two parallel plates with a diameter of 2.5cm. The coated board was prepared at a rate of 5 ° C / min from 150 ° C at 25 ° C and maintained at that temperature for 90 minutes. The storage elasticity G 'and loss elasticity G "were measured. The value of the storage elasticity G' is The time point at which the loss elastic modulus G ”is raised is used as the turn-off time and used as an indicator of the hardening speed. The measurement was performed using a viscoelasticity measuring device (DA Insell Corporation, model ARES-G2).

[Evaluation of hardness increase] Pour the thermally conductive silicone composition into a frame of 6 cm × 6 cm × 6 mm, and heat at 150 ° C. for 90 minutes to prepare a thin sample. After weighing two of these samples, the hardness was measured using an Asker C hardness tester as the initial hardness. Thereafter, it was aged at 125 ° C for 500 hours, and the hardness was measured.

[Measurement of thermal resistance] Using a 15 mm × 15 mm × 1 mmt silicon wafer and a 15 mm × 15 mm × 1 mmt nickel plate to hold a thermally conductive silicone composition with a thickness of 80 μm, compress it at 0.7 MPa for 15 minutes and put it directly under load Put it in a 150 ° C oven to heat-harden the thermally conductive silicone composition for 90 minutes to prepare a test piece for measuring the thermal resistance. Thereafter, a thermal cycle test (-55 ° C 125 ℃) 500 times and observe the change of thermal resistance. In addition, the measurement of the thermal resistance was performed using a nanoflash (LFA447 manufactured by Nigel Corporation).

In order to prepare the thermally conductive silicone composition of the present invention, the following components are prepared.

(A) Component A-1: Both ends are dimethylvinylsilyl chain-sealed, dimethylpolysiloxane with a dynamic viscosity of 600 mm ² / s at 25 ° C.

(B) Component B-1: dimethyl polysiloxane with one end capped with trialkoxysilyl chain and represented by the following formula

(C) Ingredients Using a 5 liter planetary mixer (manufactured by Inoue Co., Ltd.) at room temperature, the following aluminum powder or aluminum oxide powder and zinc oxide powder were mixed at the mass mixing ratio of Table 1 below for 15 minutes to obtain C-1 and C-2. Aluminum powder with an average particle size of 10 μm (thermal conductivity: 236 W / m‧ ° C.) Aluminum oxide powder with an average particle size of 6 μm (thermal conductivity: 27 W / m‧ ° C.) Zinc oxide powder with an average particle size of 0.6 μm (thermal conductivity: 25 W / m‧ ℃)

(D) Components Organic hydrogenated polysiloxane D-1 represented by the following formula: D-2:

(E) Component E-1: A-1 solution of platinum-divinyltetramethyldisilazane complex, containing 1% by mass of platinum atoms

(F) Ingredient F-1: Pyrogallazole

(G) component G-1: 3-isocyanate propyl triethoxysilane G-2: 3-isocyanate propyl trimethoxysilane G-3: 3-isocyanate propyl tri (trimethylsiloxy) silane

(H) Component H-1: 1-ethynyl-1-cyclohexanol

The components (A) to (H) are mixed as follows to obtain the thermally conductive silicone compositions of Examples 1 to 6 and Comparative Examples 1 to 6. That is, after obtaining the component (A) with a 5 liter planetary mixer (manufactured by Inoue Co., Ltd.), add the components (B) and (C) according to the addition amounts shown in Tables 2 and 3, and mix at 170 ° C for 1 hour . After cooling to normal temperature, add the components (D), (E), (F), (G) and (H) according to the addition amounts shown in Table 2 and Table 3 and mix well.

Claims (6)

A thermally conductive silicone composition comprising (A) an organic polysiloxane (B) having at least two alkenyl groups in one molecule and a dynamic viscosity at 25 ° C of 10 to 100,000 mm ² / s (B) General formula (1) (In the formula, R ¹ is an alkyl group having 1 to 6 carbon atoms, and a is a positive number of 5 to 100) The single-terminal trifunctional hydrolyzable methyl polysiloxane represented by: relative to 100 parts by mass of (A) component is 10 to 150 parts by mass (C) Thermally conductive filler with a thermal conductivity of 10 W / m‧ ° C or higher: 500 to 3,000 parts by mass (D) per molecule with respect to 100 parts by mass of (A) component and (B) component in total Organic hydrogenated polysiloxanes containing at least two hydrogen atoms directly bonded to silicon atoms: the number of {(D) Si-H groups} / {(A) number of alkenyl groups} is Amount of 0.5-1.5 (E) A catalyst selected from the group consisting of platinum and platinum compounds: Amount of platinum atoms relative to (A) component in an amount of 0.1-500 ppm (F) Triazole compounds: relative to (E) The platinum atom 1 mole of the component is 2 to 1,000 moles. (G) Isocyanate-based compound: 0.1 to 10 moles relative to the triazole compound 1 of the component (F). The thermally conductive silicone composition according to claim 1, wherein component (F) is selected from 1,2,3-triazole, 1,2,4-triazole and derivatives of these. The thermally conductive silicone composition according to claim 2, wherein the component (F) is benzotriazole. The thermally conductive silicone composition according to any one of claims 1 to 3, wherein the component (G) is selected from alkyl isocyanate-based compounds, aryl isocyanate-based compounds, and isocyanate silane-based compounds. The thermally conductive silicone composition according to claim 4, wherein the component (G) is the following formula (2) (In the formula, R ² is an alkyl group or a trialkylsilyl group, and b is an integer of 1 to 6). The thermally conductive silicone composition according to claim 1, which additionally contains (H) a reaction inhibitor selected from the group consisting of acetylene compounds, nitrogen compounds, organic phosphorus compounds, oxime compounds and organic chlorine compounds: relative to (A) The composition is 0.1 to 5 mass%.