Thermally conductive silicone composition and method for producing same

Abstract

This thermally conductive silicone composition comprises a matrix resin component and thermally conductive inorganic particles, wherein the matrix resin component includes (A) an unreactive liquid dimethylpolysiloxane having a kinematic viscosity of 100-10,000 mm2 / s at 25°C, and (B) a preliminarily crosslinked silicone gel crosslinked product, wherein: 40-97 mass% of the unreactive liquid dimethylpolysiloxane (A) and 3-60 mass% of the silicone gel crosslinked product (B) are contained with respect to 100 mass% of the matrix resin component; and 81-97 mass% of the thermally conductive inorganic particles are contained with respect to 100 mass% of the composition. As a result, the present invention provides: a thermally conductive silicone composition which does not deviate from a mounting position even when a thermal shock is applied to a semiconductor device and is capable of sufficiently maintaining thermal conductivity; and a method for producing same.

Description

Thermally conductive silicone composition and method for producing the same

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

[0002] Recent advancements in the performance of semiconductors such as CPUs have been remarkable, and consequently, the amount of heat generated has also increased dramatically. Therefore, heat sinks are attached to heat-generating electronic components, and thermally conductive silicone compositions are used to improve the adhesion between heat-generating elements such as semiconductors and the heat sinks. However, thermally conductive silicone compositions have a problem in that, when used for a long period of time, they leak out from the heat dissipation area due to thermal shock of semiconductor elements, creating voids in the heat dissipation area and causing a phenomenon known as pumping out. Patent Document 1 proposes a thermally conductive silicone composition containing a specific cyclic organopolysiloxane and being crosslinked. Patent Document 2 proposes a thermally conductive silicone composition using hydrosilylated catalyst fine particles having a microcapsule structure and being crosslinked. Patent Documents 3 and 4 propose thermally conductive silicone compositions using organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule and being crosslinked.

[0003] Japanese Patent Publication No. 2023-026788, Japanese Patent Publication No. 2021-147591, Japanese Patent Publication No. 2021-098804, Japanese Patent Publication No. 2024-035628

[0004] However, the conventional thermally conductive silicone composition described above is a liquid, and therefore, due to thermal shock to the semiconductor device, the composition can shift away from the mounting area, leading to a decrease in thermal conductivity and ultimately causing malfunction of the device.

[0005] To solve the aforementioned conventional problems, the present invention provides a thermally conductive silicone composition and a method for manufacturing the same, in which the composition does not shift from the mounting part even when subjected to thermal shock of semiconductor elements, and in which sufficient thermal conductivity is maintained.

[0006] One embodiment of the present invention is a thermally conductive silicone composition comprising a matrix resin component and thermally conductive inorganic particles, wherein the matrix resin component comprises the following (A) and (B): (A) having a kinematic viscosity of 100 to 10,000 mm at 25°C ２ The present invention relates to a thermally conductive silicone composition comprising: (A) a non-reactive liquid dimethylpolysiloxane of 0 / s; (B) a pre-crosslinked silicone gel crosslinked product; 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, with respect to 100% by mass of the matrix resin component; the thermally conductive inorganic particles are 81 to 97% by mass with respect to 100% by mass of the composition, and the remainder being the matrix resin component.

[0007] Another embodiment of the present invention relates to a method for producing the above-mentioned thermally conductive silicone composition, comprising the steps of: (1) uniformly stirring an uncrosslinked precursor of component (B); (2) heating the material obtained in step (1) to cause crosslinking; and (3) uniformly mixing the crosslinked component (B) obtained in step (2), component (A), and thermally conductive inorganic particles to obtain a paste-like mixture.

[0008] The present invention relates to a matrix resin component comprising the following (A) and (B), wherein (A) has a kinematic viscosity of 100 to 10,000 mm at 25°C. ２ The composition comprises (A) a non-reactive liquid dimethylpolysiloxane of 0 / s, (B) a pre-crosslinked silicone gel crosslinked product, and 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. With respect to 100% by mass of the composition, the thermally conductive inorganic particles make up 81 to 97% by mass, and the remainder is the matrix resin component. As a result, even if there is thermal shock such as that to semiconductor elements, the composition will not shift from the mounting part, and a thermally conductive silicone composition that can maintain sufficient thermal conductivity can be provided. Therefore, the quality of the mounted product can be maintained even after long-term use. Furthermore, the manufacturing method of the present invention can efficiently and rationally produce a thermally conductive silicone composition.

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

[0010] The inventors investigated why conventional thermally conductive silicone compositions lose their thermal conductivity due to thermal shocks in semiconductor devices, causing the composition to shift away from the mounting area. As a result, they conceived the idea of ​​incorporating a pre-crosslinked silicone gel as part of the matrix resin component into the composition. By using a pre-crosslinked silicone gel, a skeletal structure is formed, which prevents the composition from shifting away from the mounting area even when subjected to thermal shocks, thus maintaining sufficient thermal conductivity and preserving the quality of the mounted product even after long-term use. In this invention, "pre-" refers to the state before the components (A) and (B) and the thermally conductive inorganic particles are uniformly mixed. Furthermore, "crosslinking" refers to a three-dimensional network structure, and the reaction is an addition reaction.

[0011] Component (A) of the present invention has a kinematic viscosity of 100 to 10,000 mm at 25°C. ２ It is a non-reactive liquid dimethylpolysiloxane with a concentration of 1 / s. Preferably, 100 to 5000 mm. ２ / s, more preferably 100 to 3000 mm ２ The ratio is / s. Component (A) is necessary to ensure fluidity so that the composition can be dispensed from the nozzle and supplied to electronic components. Furthermore, since it is a non-reactive liquid dimethylpolysiloxane, it does 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 product composition can be maintained. If the matrix resin component is only unreactive dimethyl silicone, the temperature dependence of the silicone is high, and fluidity increases at high temperatures, making it prone to detachment and shifting from the mounting part. However, when a silicone gel crosslinked product is blended with the matrix resin component, fluidity decreases regardless of temperature, and sagging can be suppressed. Furthermore, if the matrix resin component is only a silicone gel crosslinked product, it cannot be kneaded with the filler and a composition cannot be obtained, or even if a composition is obtained, the discharge performance is significantly poor. With respect to 100% by mass of the matrix resin component, the amount of unreactive liquid dimethylpolysiloxane (A) is 40 to 97% by mass, and the amount of silicone gel crosslinked product (B) is 3 to 60% by mass. More preferably, component (A) is 45 to 95% by mass, component (B) is 5 to 55% by mass, and even more preferably, component (A) is 50 to 90% by mass, and component (B) is 10 to 50% by mass. This allows for both reduced dripping and improved dispensing from the syringe.

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

[0014] In the present invention, it is preferable that the pre-crosslinked silicone gel crosslinked component (B) contains: (B-1) a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule; (B-2) a 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 groups in component (B-1); and (B-3) a platinum catalyst in an effective amount. This allows the skeletal structure to be maintained. In other words, a polyorganosiloxane having alkenyl groups bonded to silicon atoms (B-1) and a polyorganohydrogensiloxane having hydrogen atoms bonded to silicon atoms (B-2) are provided, and the molar ratio (hereinafter H / Vi) between the alkenyl groups bonded to silicon atoms in component (B-1) and the hydrogen atoms in component (B-2) is such that the H / Vi ratio 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 liquid form. The inclusion of component (B) facilitates application with a dispenser and provides 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 a Thermal Interface Material (TIM). The D50 (median diameter) of the cumulative particle size distribution of the thermally conductive particles based on volume is preferably 0.01 to 150 μm, more preferably 0.05 to 130 μm, and even more preferably 0.1 to 120 μm. Note that 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 kneading with the other components. The heat resistance improver is preferably 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. Furthermore, a mixture of benzimitazolone and a non-reactive liquid silicone resin is preferred because it is easy to mix into the composition.

[0018] The thermally conductive silicone composition preferably further contains a terminally trimethoxy linear polydimethylsiloxane represented by 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 terminally trimethoxy group of the following formula (Chemical Formula 1) chemically reacts with the surface of the thermally conductive inorganic particles, generating low molecular weight substances such as methanol. However, these substances evaporate out of the composition and do not remain in it, thus increasing the heat resistance. However, Me is a methyl group, n-Bu is a n-butyl group, and n = 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. A thermal conductivity of this value makes it suitable as a thermally conductive material (TIM).

[0020] The thermally conductive silicone composition is preferably dispensed in a 30 mL syringe with a discharge hole diameter of 2.5 mm and a discharge pressure of 0.5 MPa for 6 seconds, resulting in a discharge volume of 1 to 8 g. This allows for smooth application by 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, and the two plates are held vertically in a heat shock testing machine, and the temperature is maintained at -40°C and 125°C for 30 minutes each, for 100 cycles, it is preferable that the drop of the thermally conductive silicone composition is within 3 mm. This ensures 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 (B) component precursor. In this step, mixing and stirring is performed using a mixing and stirring device such as a planetary mixer. (2) A step of heating and crosslinking the obtained product in step (1). The heating conditions are 100°C to 150°C for 5 to 60 minutes to cause crosslinking. Heat crosslinking causes the silicone gel crosslinked product to form a skeletal structure. (3) A step of uniformly mixing the crosslinked (B) component obtained in step (2) with components (A), (C), and (D) to obtain a liquid composition. In this step as well, mixing and stirring is performed uniformly using a mixing and stirring device such as a planetary mixer. (4) When adding the surface treatment agent of component D, the mixture is heated at 100 to 200°C for 5 minutes to 48 hours to promote the progress of the filler surface treatment and remove low boiling point substances.

[0023] The (B) component precursor of the uncrosslinked material preferably contains: (B-1) a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule; (B-2) a 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 groups in component (B-1); and (B-3) a platinum catalyst: an effective amount.

[0024] The resulting thermally conductive silicone composition preferably has a viscosity at 25°C measured by a rotational viscometer 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 results in a thermally conductive composition with excellent workability, making it suitable as a Thermal Interface Material (TIM).

[0025] At least some of the thermally conductive particles may be surface-treated with a coupling agent beforehand. An example of a coupling agent is R(CH ３ ) ａ Si (OR') ４－ａ The silane compound is represented by (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 hydrolysate thereof. Examples of the alkoxysilane compound of the above chemical formula (hereinafter simply referred to as "silane") include methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, and octadecyltriethoxysilane. The silane compound can be used individually or in combination of two or more. It is preferable to add 0.1 to 5.0 parts by mass of the coupling agent per 100 parts by mass of the thermally conductive particles. In particular, if the fine thermally conductive particles with a median diameter D = 50 of 1 μm or less are surface-treated with a coupling agent beforehand, the mixability when compounding will improve and the workability will be enhanced.

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

[0027] The thermally conductive silicone resin composition of the present invention is a non-curing thermally conductive composition. Therefore, a curing catalyst and curing agent are not required, but they may be added in some cases.

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

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

[0030] Figure 2 is a schematic cross-sectional view of a heat-conductive composition in one embodiment of the present invention, which is extruded into and incorporated into a heat-dissipating structure 16. The heat-conductive composition 11b dissipates heat generated by electronic components 13 such as semiconductor elements, and is extruded onto the main surface 12a of the heat spreader 12 facing the electronic components 13, and is sandwiched between the electronic components 13 and the heat spreader 12. The heat-conductive composition 11a is also sandwiched between the heat spreader 12 and the heat sink 15. Together with the heat spreader 12, the heat-conductive compositions 11a and 11b constitute a heat-dissipating member that dissipates heat from the electronic components 13. The heat spreader 12 is formed, for example, in the shape of a rectangular plate and has a main surface 12a facing the electronic components 13 and side walls 12b erected along the outer circumference of the main surface 12a. The heat spreader 12 has a main surface 12a surrounded by side walls 12b onto which a heat conductive composition 11b is discharged, and a heat sink 15 is provided on the other surface 12c opposite to the main surface 12a via the heat 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.

[0031] The present invention will be explained below using examples. The present invention 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 (compliant with ISO 22007-2:2008). As shown in Figure 1A, this thermal conductivity measuring device 1 sandwiches a polyimide film sensor 2 between two samples 3a and 3b, applies a constant power to the sensor 2 to generate a constant amount of heat, and analyzes the thermal characteristics from the temperature rise value of the sensor 2. The tip 4 of the sensor 2 has a diameter of 7 mm and, as shown in Figure 1B, has a double spiral structure of electrodes, with an electrode 5 for applied current and an electrode for resistance (temperature measurement electrode) 6 arranged at the bottom. The measurement sample 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 formula (Equation 1). <Viscosity> The viscosity of the thermal conductive composition was measured using a MARS III viscosity / viscoelasticity measuring device manufactured by HAAKE at a temperature of 25°C, a measurement thickness of 0.5 mm, and a rotation speed of 1.0 (1 / s). The average value of the measurements taken from 30 seconds to 1 minute after the start of rotation was recorded as the viscosity. <Drop Test> The viscosity was measured by the drop test shown in Figures 3A-D. 1.0 g of thermal conductive composition 26 was applied between an aluminum plate 24 measuring 40 mm in length, 100 mm in width, and 5 mm in thickness, and a glass plate 23 measuring 40 mm in length, 100 mm in width, and 5 mm in thickness (Figure 3A), and compressed and sandwiched with a spacer 25 in between to a thickness of 1.0 mm (Figure 3B). 27 is the thermal conductive composition compressed to a thickness of 1.0 mm. Next, it was placed in a heat cycle tester so that the gap between the aluminum plate 24 and the glass plate 23 was vertical (Figure 3C). 28 is the test piece before the test. In this state, a heat cycle test was performed by holding the sample at -40°C and 125°C for 30 minutes each. After 100 cycles, the test specimen was removed and observed to see if the thermal conductive composition 27 had fallen off. 29 is the test specimen after the test (Figure 3D), and 30 is the fall distance. Judgment criteria OK: The composition fell within 3 mm NG: It exceeded 3 mm <Discharge test> The thermal conductive composition was filled into a 30 mL syringe PSY-30F manufactured by Musashi Engineering Co., Ltd., and the discharge amount was measured when it was discharged for 6 seconds at a discharge pressure of 0.5 MPa at 23°C.

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

[0033]

[0034] From the above results, the following can be concluded: (1) In Examples 1 to 4, the addition of component B suppressed movement from the initial position during the drop test, and it was confirmed that the thermal conductivity was good, the viscosity was low, and the dispensability was good. Furthermore, it was confirmed that even with thermal shock to semiconductor elements, the composition did not shift from the mounting area, the thermal conductivity was sufficiently maintained, and the quality of the mounted product could be maintained even after long-term use. (2) In Comparative Example 1, the amount of component B added was too little, the dispensability was too high, and the drop test was unsuccessful (NG). (3) In Comparative Example 2, the amount of component B added was too high, and it was not possible to produce a composition. (4) Similarly, in Comparative Example 3, the amount of component B added was too high, and although movement from the initial position during the drop test was suppressed, the dispensability was poor. (5) In Comparative Example 4, the manufacturing method was different, and component B was not crosslinked in advance, so the crosslinked structure was not sufficiently constructed, movement from the initial position occurred, and the drop test was unsuccessful (NG).

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

[0036] 1 Thermal conductivity measuring device 2 Sensor 3a, 3b Sample 4 Sensor tip 5 Electrode for applied current 6 Electrode for resistance (electrode for temperature measurement) 11a, 11b Thermally conductive composition 12 Heat spreader 13 Electronic component 14 Wiring board 15 Heat sink 16 Heat dissipation structure 23 Glass plate 24 Aluminum plate 25 Spacer 26, 27 Thermally conductive composition 28 Test specimen before testing 29 Test specimen after testing 30 Drop distance

Claims

1. A thermally conductive silicone composition comprising a matrix resin component and thermally conductive inorganic particles, wherein the matrix resin component comprises the following (A) and (B): (A) having a kinematic viscosity of 100 to 10,000 mm at 25°C ２ A thermally conductive silicone composition comprising: (A) a non-reactive liquid dimethylpolysiloxane of / s; (B) a pre-crosslinked silicone gel crosslinked product; 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, with respect to 100% by mass of the matrix resin component; the thermally conductive inorganic particles are 81 to 97% by mass with respect to 100% by mass of the composition; and the remainder is the matrix resin component.

2. The thermally conductive silicone composition according to claim 1, wherein the pre-crosslinked silicone gel crosslinked component (B) comprises: (B-1) a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule; (B-2) a 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 groups in component (B-1); and (B-3) a platinum catalyst: an effective amount.

3. The thermally conductive silicone composition according to claim 1 or 2, wherein the thermally conductive silicone composition is in an uncured state.

4. The thermally conductive silicone composition according to any one of claims 1 to 3, 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 any one of claims 1 to 4, further comprising a heat resistance improver.

6. The thermally conductive silicone composition according to any one of claims 1 to 5, wherein the heat-resistant improving agent comprises a mixture of benzimitazolone and a non-reactive liquid silicone resin.

7. The thermally conductive silicone composition according to any one of claims 1 to 6, further comprising a terminally trimethoxy linear polydimethylsiloxane represented by the following formula (Chemical Formula 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 any one of claims 1 to 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 thermal conductive silicone composition according to any one of claims 1 to 8, wherein the thermal conductivity of the thermal 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 any one of claims 1 to 9, 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 any one of claims 1 to 10, 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 any one of claims 1 to 11, wherein the viscosity of the thermally conductive silicone composition 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 any one of claims 1 to 12, 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, comprising: (1) a step of uniformly stirring an uncrosslinked precursor of component (B); (2) a step of heating the material obtained in step (1) to crosslink it; and (3) a step of uniformly mixing the crosslinked component (B) obtained in step (2), component (A), and thermally conductive inorganic particles to obtain a paste-like mixture.

15. A method for producing a thermally conductive silicone composition according to claim 14, wherein the (B) precursor of the uncrosslinked material comprises: (B-1) a polyorganosiloxane having two or more alkenyl groups bonded to silicon atoms in one molecule; (B-2) a 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 groups in component (B-1); and (B-3) a platinum catalyst: an effective amount.

Images