Thermally conductive silicone composition and method for producing same

Abstract

The thermally conductive silicone composition comprises a matrix resin component and thermally conductive inorganic particles, and the matrix resin component (A) has a kinematic viscosity at 25°C of 100 to 10,000 mm 2 The thermally conductive silicone composition comprises a non-reactive liquid dimethylpolysiloxane (A) of 100% by mass / s and a pre-crosslinked silicone gel crosslinker (B), wherein the non-reactive liquid dimethylpolysiloxane (A) is 40 to 97% by mass and the silicone gel crosslinker (B) is 3 to 60% by mass relative to 100% by mass of the matrix resin component, and the thermally conductive inorganic particles are 81 to 97% by mass relative to 100% by mass of the composition. This prevents the composition from shifting from the mounting area even when subjected to thermal shocks of a semiconductor element, and provides a thermally conductive silicone composition and a method for producing the same.

Description

[Technical Field]

[0001] The present invention relates to a thermally conductive silicone composition suitable for placement between a heat-generating portion of an electric or electronic component and a heat sink, and a method for producing the same. [Background technology]

[0002] In recent years, the performance of semiconductors such as CPUs has improved dramatically, resulting in enormous increases in the amount of heat they generate. Heat-generating electronic components are therefore fitted with heat sinks, and thermally conductive silicone compositions are used to improve the adhesion between the heat sink and the semiconductor or other heat-generating component. However, when used over long periods of time, thermally conductive silicone compositions can flow out of the heat sink due to the thermal shock of the semiconductor element, creating voids in the heat sink and causing a phenomenon known as pumping out. Patent Document 1 proposes a thermally conductive silicone composition containing a specific cyclic organopolysiloxane and crosslinked. Patent Document 2 proposes a thermally conductive silicone composition crosslinked using hydrosilylation catalyst particles having a microcapsule structure. Patent Documents 3 and 4 propose thermally conductive silicone compositions crosslinked using an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms per molecule. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-026788 [Patent Document 2] Japanese Patent Application Publication No. 2021-147591 [Patent Document 3] Japanese Patent Publication No. 2021-098804 [Patent Document 4] Japanese Patent Application Laid-Open No. 2024-035628 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because the thermally conductive silicone compositions of the above-mentioned prior art are liquid, they can shift from the mounting area due to thermal shock to the semiconductor element, reducing thermal conductivity and ultimately leading to malfunction of the element.

[0005] In order to solve the above-mentioned problems of the conventional art, the present invention provides a thermally conductive silicone composition that will not shift from the mounting area even when subjected to thermal shocks on semiconductor elements and that can adequately maintain thermal conductivity, and a method for producing the same. [Means for solving the problem]

[0006] One embodiment of the present invention is a thermally conductive silicone composition comprising a matrix resin component and thermally conductive inorganic particles, The matrix resin component contains the following (A) and (B): (A) Kinematic viscosity at 25°C is 100 to 10,000 mm 2 / s non-reactive liquid dimethylpolysiloxane, (B) Pre-crosslinked silicone gel crosslinker; the non-reactive liquid dimethylpolysiloxane (A) is 40 to 97 mass% and the silicone gel crosslinked product (B) is 3 to 60 mass% relative to 100 mass% of the matrix resin component, The pre-crosslinked silicone gel crosslinked product (B) is (B-1) a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms per molecule; (B-2) Polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms per molecule: the hydrogen atoms in the component (B-2) are crosslinked in an amount of 0.1 to 5.0 mol per 1 mol of alkenyl groups in the component (B-1); (B-3) Platinum catalyst: effective amount Including, The present invention relates to a thermally conductive silicone composition, wherein the thermally conductive inorganic particles account for 81 to 97% by mass relative to 100% by mass of the composition.

[0007] Another embodiment of the present invention is a method for producing the thermally conductive silicone composition described above, comprising the steps of: (1) a step of uniformly stirring an uncrosslinked component (B) precursor; (2) a step of heating and crosslinking the product obtained in the step (1); (3) A step of uniformly mixing the crosslinked (B) component crosslinked in the step (2) with the (A) component and thermally conductive inorganic particles to obtain a paste-like mixture. Including fruit, The uncrosslinked precursor of component (B) is (B-1) a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms per molecule; (B-2) Polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms per molecule: the hydrogen atoms in the component (B-2) are crosslinked in an amount of 0.1 to 5.0 mol per 1 mol of alkenyl groups in the component (B-1); (B-3) Platinum catalyst: effective amount Contains The present invention relates to a method for producing a thermally conductive silicone composition. [Effects of the Invention]

[0008] The matrix resin component of the present invention comprises the following (A) and (B), and (A) has a kinematic viscosity at 25°C of 100 to 10,000 mm 2 The composition comprises a non-reactive liquid dimethylpolysiloxane (A) of 40-97% by mass and a pre-crosslinked silicone gel crosslinker (B) of 100% by mass of the matrix resin component, and the non-reactive liquid dimethylpolysiloxane (A) is 40-97% by mass and the silicone gel crosslinker (B) is 3-60% by mass. The composition comprises 81-97% by mass of the thermally conductive inorganic particles, with the remainder being the matrix resin component. This provides a thermally conductive silicone composition that will not shift from its mounting location even when subjected to thermal shocks such as those of semiconductor devices, and that can adequately maintain thermal conductivity. Therefore, the quality of the mounted product can be maintained even after long-term use. Furthermore, the manufacturing method of the present invention allows for efficient and rational production of a thermally conductive silicone composition. [Brief explanation of the drawings]

[0009] [Figure 1] 1A-B are schematic explanatory views showing a method for measuring the thermal conductivity of a sample in one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view illustrating a method of using the thermally conductive composition according to one embodiment of the present invention. [Figure 3] 3A-3D are schematic explanatory views of a drop test in one embodiment of the present invention. [Figure 4]FIG. 4 is a scanning electron microscope (SEM) photograph (magnification: 5000 times) of crushed alumina (D50 (median diameter) is 0.3 μm) used in one example of the present invention. [Figure 5] FIG. 5 is an SEM photograph (magnification 2500 times) of spherical alumina (D50 (median diameter) 2.0 μm, top cut 75 μm) used in one example of the present invention. [Figure 6] FIG. 6 is an SEM photograph (magnification 2000 times) of crushed alumina (D50 (median diameter) 2.2 μm, surface-treated product) used in one example of the present invention. [Figure 7] FIG. 7 is an SEM photograph (magnification 1000 times) of spherical alumina (D50 (median diameter) 20 μm, top cut 55 μm) used in one example of the present invention. [Figure 8] FIG. 8 is an SEM photograph (magnification 1000 times) of spherical alumina (D50 (median diameter) 35 μm, top cut 75 μm) used in one example of the present invention. [Figure 9] FIG. 9 is an SEM photograph (magnification: 500 times) of crushed aluminum nitride (D50 (median diameter) is 20 μm) used in one example of the present invention. [Figure 10] FIG. 10 is an SEM photograph (magnification 100 times) of spherical alumina (D50 (median diameter) 120 μm, top cut 150 μm) used in one example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present inventors investigated why conventional thermally conductive silicone compositions tend to shift from the mounting area due to thermal shocks of semiconductor devices, resulting in reduced thermal conductivity. As a result, they came up with the idea of ​​incorporating a pre-crosslinked silicone gel crosslinked product into the composition as part of the matrix resin component. They discovered that using a pre-crosslinked silicone gel crosslinked product creates a skeletal structure that prevents the composition from shifting from the mounting area even when subjected to thermal shocks, thereby maintaining sufficient thermal conductivity and ensuring the quality of the mounted product even after long-term use. In this specification, "pre-crosslinking" refers to the time before the components (A), (B), and thermally conductive inorganic particles are uniformly mixed. Furthermore, "crosslinking" refers to a three-dimensional network structure, and the reaction is an addition reaction.

[0011] The component (A) of the present invention has a kinematic viscosity at 25°C of 100 to 10,000 mm 2 / s non-reactive liquid dimethylpolysiloxane. 2 / s, and more preferably 100 to 3000 mm 2 / s. Component (A) is necessary to ensure the fluidity that allows the composition to be discharged from a nozzle and applied to electronic components. Furthermore, because it is a non-reactive liquid dimethylpolysiloxane, it will not deteriorate even after long-term use.

[0012] Component (B) of the present invention is a pre-crosslinked silicone gel crosslinked product. The skeletal structure of the pre-crosslinked silicone gel crosslinked composition can be maintained. If the matrix resin component is solely non-reactive dimethyl silicone, the silicone is highly temperature-dependent, and its fluidity increases at high temperatures, making it prone to falling off and slipping from the mounting area. However, by blending the silicone gel crosslinked product into the matrix resin component, fluidity decreases regardless of temperature, preventing dripping. Furthermore, if the matrix resin component is solely a silicone gel crosslinked product, it will be unable to be kneaded with the filler, making it impossible to obtain a composition, or even if a composition is obtained, its dischargeability will be significantly poor. With respect to 100% by mass of the matrix resin component, the non-reactive liquid dimethylpolysiloxane (A) is 40 to 97% by mass, and the silicone gel cross-linked product (B) is 3 to 60% by mass. More preferably, the (A) component is 45 to 95% by mass, and the (B) component is 5 to 55% by mass, and even more preferably, the (A) component is 50 to 90% by mass, and the (B) component is 10 to 50% by mass. This allows for both suppression of dripping and improved dischargeability from a syringe.

[0013] The thermally conductive inorganic particles account for 81 to 97% by mass of the composition (100% by mass), with the remainder being the matrix resin component. The thermally conductive inorganic particles account for more preferably 83 to 97% by mass, and even more preferably 85 to 96% by mass. This allows for increased thermal conductivity.

[0014] In the present invention, the pre-crosslinked silicone gel crosslinked product (B) is (B-1) a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms per molecule; (B-2) Polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms per molecule: the hydrogen atoms in the component (B-2) are crosslinked in an amount of 0.1 to 5.0 mol per 1 mol of alkenyl groups in the component (B-1); (B-3) Platinum catalyst: effective amount It is preferable that the component (B-1) contains a polyorganosiloxane having an alkenyl group bonded to a silicon atom and a polyorganohydrogensiloxane having a hydrogen atom bonded to a silicon atom. In other words, the molar ratio of the alkenyl group bonded to the silicon atom in component (B-1) to the hydrogen atom in component (B-2) (hereinafter referred to as H / Vi) is 0.1 to 5.0, more preferably 0.2 to 4.0, and even more preferably 0.3 to 3.0.

[0015] The thermally conductive silicone composition is preferably in a liquid form. By including component (B), the composition can be easily applied with a dispenser and has good drop resistance.

[0016] The thermally conductive inorganic particles are preferably at least one inorganic particle selected from the group consisting of aluminum oxide (alumina), zinc oxide, magnesium oxide, aluminum nitride, boron nitride, aluminum hydroxide, and silicon carbide. These inorganic particles have high thermal conductivity and are suitable as TIM (Thermal Interface Material). The D50 (median diameter) of the cumulative particle size distribution on a volume basis of the thermally conductive particles is preferably 0.01 to 150 μm, more preferably 0.05 to 130 μm, and even more preferably 0.1 to 120 μm. The thermally conductive inorganic particles are also called thermally conductive fillers.

[0017] The thermally conductive silicone composition preferably further contains a heat resistance improver. To improve the dispersibility of the heat resistance improver in the composition, it may be used as a mixture with a non-reactive liquid silicone resin before being kneaded with other components. The heat resistance improver is preferably used in an amount of 0.5 to 10 parts by mass, more preferably 1 to 9 parts by mass, per 100 parts by mass of the matrix resin. A mixture of benzimidazolone and a non-reactive liquid silicone resin is also preferred because it is easy to mix into the composition.

[0018] The thermally conductive silicone composition preferably further contains a linear polydimethylsiloxane having a trimethoxy group at one end, as shown in the following formula (Chemical Formula 1): This surface treatment agent is preferably added in an amount of 1 to 20 parts by mass, more preferably 3 to 17 parts by mass, and even more preferably 5 to 15 parts by mass, per 100 parts by mass of the matrix resin component. The trimethoxy group at one end of the formula (Chemical Formula 1) chemically reacts with the surface of the thermally conductive inorganic particles to generate low-molecular-weight substances such as methanol, but these evaporate outside the composition and do not remain within the composition, thereby improving heat resistance. [ka] Here, Me is a methyl group, n-Bu is a normal butyl group, and n is 5 to 1000. n is preferably 10 to 900, more preferably 20 to 800, and even more preferably 30 to 700.

[0019] The thermal conductivity of the thermally conductive silicone composition is preferably 1.0 W / m·K or more and 30 W / m·K or less. This thermal conductivity makes it suitable as a thermally conductive material (TIM).

[0020] The thermally conductive silicone composition is preferably filled into a 30 mL syringe and discharged in 6 seconds through a discharge hole with a diameter of 2.5 mm at a discharge pressure of 0.5 MPa, with a discharge amount of 1 to 8 g, which allows for smooth application using a dispenser.

[0021] In a heat shock test in which 1.0 g of the thermally conductive silicone composition is placed between two plates, compressed to a thickness of 1.0 mm, the two plates are held vertically and placed in a heat shock tester, and the plates are held at -40°C and 125°C for 30 minutes each, for 100 cycles, the thermally conductive silicone composition preferably falls no more than 3 mm, thereby maintaining good drop resistance.

[0022] The method for producing the thermally conductive silicone composition of the present invention comprises the following steps. (1) A step of uniformly stirring the uncrosslinked component (B) precursor In this step, mixing and stirring is carried out using a mixing and stirring device such as a planetary mixer. (2) A step of heating and crosslinking the product obtained in the step (1) The heating conditions are 100° C. to 150° C. for 5 to 60 minutes to cause crosslinking, which causes the crosslinked silicone gel to form a skeletal structure. (3) A step of uniformly mixing the crosslinked (B) component crosslinked in the step (2) with the (A), (C), and (D) components to obtain a liquid composition. In this step as well, a mixing and stirring device such as a planetary mixer is used to mix and stir the ingredients uniformly. (4) When the surface treatment agent of component D is added, the mixture is heated at 100 to 200°C for 5 minutes to 48 hours to promote the progress of the surface treatment of the filler and remove low boiling point substances.

[0023] The uncrosslinked precursor of component (B) is (B-1) a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms per molecule; (B-2) Polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms per molecule: the hydrogen atoms in the component (B-2) are crosslinked in an amount of 0.1 to 5.0 mol per 1 mol of alkenyl groups in the component (B-1); (B-3) Platinum catalyst: effective amount It is preferred that the compound contains:

[0024] The viscosity of the resulting thermally conductive silicone composition at 25°C, as measured with a rotational viscometer, is preferably in the range of 200 to 70,000 Pa·s, more preferably 300 to 5,000 Pa·s, and even more preferably 500 to 3,000 Pa·s.This makes the thermally conductive composition easy to work with and suitable as a TIM (thermal interface material).

[0025] At least a portion of the thermally conductive particles may be surface-treated in advance with a coupling agent. An example of the coupling agent is R(CH3) a Si(OR') 4-a(R is an unsubstituted or substituted organic group having 1 to 20 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, and a is 0 or 1), or a partial hydrolyzate thereof. Examples of alkoxysilane compounds (hereinafter simply referred to as "silane") having the above chemical formula include methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, and octadecyltriethoxysilane. The above silane compounds can be used alone or in combination. The coupling agent is preferably added in an amount of 0.1 to 5.0 parts by mass per 100 parts by mass of the thermally conductive particles. In particular, if fine thermally conductive particles with a median diameter D=50 of 1 μm or less are surface-treated with a coupling agent in advance, the particles will be easier to mix when compounded, improving workability.

[0026] The thermally conductive silicone composition of the present invention can be used in the form of grease, putty, liquid, etc., but is preferably used as a thermally conductive grease. The thermally conductive composition is suitable for use as a thermal interface material (TIM) filled into a syringe and applied between heat-generating and heat-dissipating parts of electronic components, etc.

[0027] The thermally conductive silicone resin composition of the present invention is a non-curable thermally conductive composition, and therefore does not require a curing catalyst or curing agent, although they may be added in some cases.

[0028] The composition of the present invention may contain other components as needed. For example, heat resistance improvers such as red iron oxide, titanium oxide, and cerium oxide, flame retardants, and flame retardant assistants may be added. Organic or inorganic particle pigments may be added for coloring or toning purposes. Alkoxy group-containing silicones may be added as materials for surface treatment of thermally conductive inorganic particles.

[0029] The composition of the present invention can be filled into various containers such as pails, syringes, cartridges, etc. to form a product.

[0030] 2 is a schematic cross-sectional view of a heat dissipation structure 16 incorporating a thermally conductive composition according to one embodiment of the present invention. The thermally conductive composition 11b dissipates heat generated by an electronic component 13, such as a semiconductor element. The thermally conductive composition 11b is dispensed onto a main surface 12a of the heat spreader 12 that faces the electronic component 13, and is sandwiched between the electronic component 13 and the heat spreader 12. The thermally conductive composition 11a is sandwiched between the heat spreader 12 and a heat sink 15. The thermally conductive compositions 11a and 11b, together with the heat spreader 12, constitute a heat dissipation member that dissipates heat from the electronic component 13. The heat spreader 12 is formed, for example, in the shape of a rectangular plate and has a main surface 12a that faces the electronic component 13 and a sidewall 12b that extends along the outer periphery of the main surface 12a. The heat spreader 12 has a main surface 12a surrounded by sidewalls 12b onto which a thermally conductive composition 11b is dispensed, and a heat sink 15 is provided on a surface 12c opposite to the main surface 12a via the thermally conductive composition 11a. The electronic component 13 is, for example, a semiconductor element such as a BGA, and is mounted on a wiring board 14. [Example]

[0031] The present invention will be described below using examples, but is not limited to these examples. Various parameters were measured by the following methods. <Thermal conductivity> The thermal conductivity of the thermally conductive composition was measured using a hot disk (ISO 22007-2:2008 compliant). As shown in Figure 1A, this thermal conductivity measuring device 1 sandwiches a polyimide film sensor 2 between two samples 3a and 3b. A constant power is applied to the sensor 2, generating a constant amount of heat. The thermal characteristics are analyzed based on the temperature rise of the sensor 2. The sensor 2 has a 7 mm diameter tip 4 and, as shown in Figure 1B, a double spiral electrode structure, with an applied current electrode 5 and a resistance electrode (temperature measurement electrode) 6 located at the bottom. Measurement samples can be obtained by rolling a degassed thermally conductive liquid composition to a thickness of 7 mm or more. The thermal conductivity is calculated using the following equation (Equation 1).

number

[0032] (Examples 1 to 4, Comparative Examples 1 to 4) 1. Raw material ingredients (1) Matrix resin components (A1 and A2 components) A1 component has a kinematic viscosity of 100mm at 25°C 2 / s non-reactive liquid dimethylpolysiloxane (Momentive Performance Materials Japan) was used. A2 component has a kinematic viscosity of 300mm at 25°C 2 A non-reactive liquid dimethylpolysiloxane (Dow-Toray) with 1 / s was used. (2) Gel cross-linked components (B1 and B2 components) The crosslinked gel components B1 and B2 were crosslinked materials 1 and 2 listed in Table 1 below. The vinyl silicone B-1-1 listed in Table 1 was manufactured by Elkem, product number BLUESIL FLD 621 V350; the vinyl silicone B-1-2 was manufactured by Dow Corning, product number XIAMETER RBL9117; the crosslinking agent B-2 was manufactured by Dow-Toray, product number SILASTIC RD-1 RUBBER Additive; and the platinum catalyst B-3 was manufactured by Momentive Performance Materials Japan, product number XC91A-6529. The kinematic viscosities of the vinyl silicone B-1-1 and vinyl silicone B-1-2 are listed in the catalog. The components were mixed and stirred in a planetary mixer, then heated to 100°C for 20 minutes to crosslink the components. [Table 1] (3) Thermally conductive inorganic particles (component C) As the component (C-1), crushed alumina D50=0.3 μm shown in FIG. 4 was used. As the component (C-2), spherical alumina D50=2.0 μm (75 μm top cut product) shown in FIG. 5 was used. The (C-3) component used was crushed alumina D50=2.2 μm shown in FIG. 6, and a surface-treated product in which decyltrimethoxysilane was added at 1.1 wt.% relative to the alumina. As the (C-4) component, spherical alumina D50=20 μm (55 μm top cut product) shown in FIG. 7 was used. As the (C-5) component, spherical alumina D50=35 μm (75 μm top cut product) shown in FIG. 8 was used. As the (C-6) component, crushed aluminum nitride D50=20 μm shown in FIG. 9 was used. As the (C-7) component, spherical alumina D50=120 μm (150 μm top cut product) shown in FIG. 10 was used. (4) Heat resistance improver (D-1 component) A mixture of benzimidazolone (25 wt.%) and non-reactive liquid silicone resin (75 wt.%) was used. (5) Surface treatment agent (ingredient D-2) A linear organopolysiloxane (n=35) having trimethoxy groups at one end and represented by the formula (Chemical Formula 1) was used. 2.Mixing method (Mixing method 1) The above raw materials were mixed and stirred in a planetary mixer to prepare a thermally conductive composition. (Mixing method 2) The above components (A), (B-1-1), (B-2), (B-3), (C), and (D-1) were mixed and stirred using a planetary mixer, then heated at 100°C for 20 minutes to crosslink, and then mixed and stirred again to form a thermally conductive composition. The compositions obtained as described above were evaluated, and the conditions and results are summarized in Tables 2 and 3 below.

[0033] [Table 2] [Table 3]

[0034] From the above results, the following can be seen: (1) It was confirmed that in Examples 1 to 4, the addition of Component B suppressed movement from the initial position during a drop test, and that the composition had good thermal conductivity, low viscosity, and good dischargeability. It was also confirmed that the composition did not shift from the mounting area even when subjected to thermal shocks such as those on semiconductor devices, and that the thermal conductivity was sufficiently maintained, allowing the quality of the mounted product to be maintained even after long-term use. (2) In Comparative Example 1, the amount of component B added was too small, the ejection tendency was too high, and the drop test was also poor (NG). (3) In Comparative Example 2, the amount of component B added was too large, and a composition could not be prepared. (4) Similarly, in Comparative Example 3, the amount of component B added was too large, and although movement from the initial position in the drop test was suppressed, the ejection properties were poor. (5) Comparative Example 4 was manufactured using a different method, and component B was not crosslinked in advance. As a result, the crosslinked structure was not sufficiently constructed, movement from the initial position occurred, and the drop test was unsuccessful (NG). [Industrial Applicability]

[0035] The thermally conductive silicone composition of the present invention is suitable as a thermally conductive material (TIM) to be interposed between a heat-generating portion of an electric or electronic part and a heat sink. [Explanation of symbols]

[0036] 1. Thermal conductivity measuring device 2 sensors 3a,3b Sample 4 Sensor tip 5 Electrode for applied current 6 Resistance electrode (temperature measurement electrode) 11a, 11b Thermally conductive composition 12 Heat spreader 13 Electronic Components 14 Wiring board 15 Heatsink 16 Heat dissipation structure 23 Glass Plate 24 Aluminum Plate 25 spacer 26,27 Thermally conductive compositions 28 Test specimen before test 29 Test piece after test 30 Fall Distance

Claims

1. A thermally conductive silicone composition comprising a matrix resin component and thermally conductive inorganic particles, The matrix resin component comprises the following (A) and (B): (A) Kinematic viscosity at 25°C is 100 to 10,000 mm 2 / s non-reactive liquid dimethylpolysiloxane, (B) Pre-crosslinked silicone gel crosslinked material, With respect to 100% by mass of the matrix resin component, the non-reactive liquid dimethylpolysiloxane (A) is 40 to 97% by mass, and the silicone gel crosslinked product (B) is 3 to 60% by mass. The thermally conductive inorganic particles comprise 81 to 97% by mass of 100% by mass of the aforementioned composition. A thermally conductive silicone composition characterized in that the remainder is the matrix resin component.

2. The aforementioned pre-crosslinked silicone gel crosslinked product (B) component, (B-1) A polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule, (B-2) Polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule: The hydrogen atoms in component (B-2) are crosslinked in an amount of 0.1 to 5.0 mol per mol of alkenyl group in component (B-1). (B-3) Platinum catalyst: Effective amount A thermally conductive silicone composition according to claim 1, comprising:

3. The thermally conductive silicone composition according to claim 1, wherein the thermally conductive silicone composition is in an uncured state.

4. The thermally conductive silicone composition according to claim 1, wherein the thermally conductive inorganic particles are at least one inorganic particle selected from the group consisting of aluminum oxide, zinc oxide, magnesium oxide, aluminum nitride, boron nitride, aluminum hydroxide, and silicon carbide.

5. The thermally conductive silicone composition according to claim 1, further comprising a heat-resistant agent.

6. The thermally conductive silicone composition according to claim 1, wherein the heat-resistant agent comprises a mixture of benzimitazolone and a non-reactive liquid silicone resin.

7. The thermally conductive silicone composition according to claim 1, further comprising a terminally trimethoxy linear polydimethylsiloxane represented by the following formula (Chemical Formula 1). 【Chemistry 1】 However, Me represents a methyl group, n-Bu represents a n-butyl group, and n = 5 to 1000.

8. The thermally conductive silicone composition according to claim 7, wherein the terminally trimethoxy linear polydimethylsiloxane represented by formula (Chemical Formula 1) is added in an amount of 1 to 20 parts by mass per 100 parts by mass of the matrix resin component.

9. The thermally conductive silicone composition according to claim 1, wherein the thermal conductivity of the thermally conductive silicone composition is 1.0 W / m·K or more and 30 W / m·K or less.

10. The thermally conductive silicone composition according to claim 1, wherein the amount dispensed when the thermally conductive silicone composition is filled into a 30 mL syringe and dispensed for 6 seconds at a discharge port diameter of 2.5 mm and a discharge pressure of 0.5 MPa is 1 to 8 g.

11. The thermal conductive silicone composition according to claim 1, wherein 1.0 g of the thermal conductive silicone composition is placed between two plates, compressed and held to a thickness of 1.0 mm, the two plates are held vertically and placed in a heat shock testing machine, and in a heat shock test in which the composition is held at -40°C and 125°C for 30 minutes each and 100 cycles are completed, the thermal conductive silicone composition falls by 3 mm or less.

12. The thermally conductive silicone composition according to claim 1, wherein the viscosity at 25°C, as measured by a rotational viscometer, is in the range of 200 to 7,000 Pa·s.

13. The thermally conductive silicone composition according to claim 1, wherein the thermally conductive silicone composition is a grease.

14. A method for producing a thermally conductive silicone composition according to any one of claims 1 to 13, (1) A step of uniformly stirring the uncrosslinked (B) component precursor, (2) A step of heating and crosslinking the material obtained in step (1), (3) A step of uniformly mixing the crosslinked component (B) obtained in step (2) above with component (A) and thermally conductive inorganic particles to obtain a paste-like mixture. A method for producing a thermally conductive silicone composition containing [a specific substance].

15. The precursor of component (B) of the aforementioned uncrosslinked material is (B-1) A polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule, (B-2) Polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule: The hydrogen atoms in component (B-2) are crosslinked in an amount of 0.1 to 5.0 mol per mol of alkenyl group in component (B-1). (B-3) Platinum catalyst: Effective amount A method for producing a thermally conductive silicone composition according to claim 14, including the following:

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