Thermally conductive silicone resin composition

Abstract

Provided is a thermally conductive silicone resin composition that has high thermal conductivity, is relatively resistant to dripping, and has good dischargeability. The composition comprises a matrix resin component (A) and thermally conductive inorganic particles (B), and the matrix resin component (A) comprises 70 to 99 parts by mass of liquid dimethylpolysiloxane (A1) and 1 to 30 parts by mass of a mixed oil (A2) of polydecene and an ethylene-propylene copolymer, per 100 parts by mass of the matrix resin component (A). The liquid dimethylpolysiloxane (A1) has a kinetic viscosity at 40° C. of 50 to 10,000 mm 2 / s, and the mixed oil (A2) has a kinetic viscosity at 40°C of 1 to 1,000 mm 2 / s, and the thermally conductive silicone resin composition contains 400 to 3000 parts by mass of the thermally conductive inorganic particles (B) per 100 parts by mass of the matrix resin component (A).

Description

[Technical field]

[0001] The present invention relates to a thermally conductive silicone resin composition that is suitable for being interposed between a heat-generating portion of an electric or electronic component or the like and a heat sink. [Background technology]

[0002] In recent years, the performance of semiconductors such as CPUs has improved remarkably, and the amount of heat generated has also increased dramatically. For this reason, heat sinks are attached to electronic components that generate heat, and thermally conductive grease is used to improve the adhesion between the heat sink and the heat source such as semiconductors. As devices become smaller, more powerful, and more highly integrated, thermally conductive grease is required to have high thermal conductivity as well as drop resistance.

[0003] JP 2018-104714 A proposes a composition containing a thermally conductive filler, a polyorganosiloxane resin containing at least one polysiloxane having one curable functional group in the molecule, and a siloxane compound having an alkoxysilyl group and a linear siloxane structure. JP 2016-044213 A proposes a thermally conductive silicone composition containing liquid silicone, a thermally conductive filler, and hydrophobic spherical silica microparticles, and having improved heat dissipation. JP 2004-131540 A proposes a resin sheet in which a thermally conductive filler is blended with an α-olefin copolymer containing two or more α-olefins having 2 to 12 carbon atoms. JP 2004-143195 A proposes a resin sheet in which a surface-treated thermally conductive filler is blended with an α-olefin copolymer containing two or more α-olefins having 2 to 12 carbon atoms. In Japanese Patent No. 7047199, the present inventors have proposed a thermally conductive grease in which a thermally conductive filler is blended with an ethylene-α-olefin copolymer. Summary of the Invention

[0004] The present invention provides a thermally conductive silicone resin composition comprising a matrix resin component (A) and thermally conductive inorganic particles (B), The matrix resin component (A) contains, relative to 100 parts by mass of the matrix resin component (A), 70 to 99 parts by mass of liquid dimethylpolysiloxane (A1), A mixed oil (A2) of polydecene and an ethylene-propylene copolymer is contained in an amount of 1 to 30 parts by mass, The liquid dimethylpolysiloxane (A1) has a kinetic viscosity at 40° C. of 50 to 10,000 mm 2 / s, The mixed oil (A2) has a kinetic viscosity at 40°C of 1 to 1,000 mm 2 / s, The thermally conductive silicone resin composition contains 400 to 3,000 parts by mass of the thermally conductive inorganic particles (B) based on 100 parts by mass of the matrix resin component (A). [Brief description of the drawings]

[0005] [Figure 1] 1A-B are explanatory diagrams showing a method for measuring the thermal conductivity of a sample in one embodiment of the present invention. [Diagram 2] 2A to 2D are schematic explanatory views illustrating a drop test used in one embodiment of the present invention. [Diagram 3] FIG. 3 is a scanning electron microscope (SEM) photograph (magnification: 5000 times) of amorphous alumina (B1) (D50 (median diameter) is 0.3 μm) used in one embodiment of the present invention. [Figure 4] FIG. 4 is an SEM photograph (magnification 2000 times) of amorphous alumina (B1) (D50 (median diameter) is 2.3 μm) used in one embodiment of the present invention. [Diagram 5] FIG. 5 is an SEM photograph (magnification 2000 times) of amorphous aluminum nitride (B2) (D50 (median diameter) is 15 μm) used in one embodiment of the present invention. [Figure 6] FIG. 6 is an SEM photograph (magnification: 100 times) of spherical alumina (B3) (D50 (median diameter) is 105 μm) used in one embodiment of the present invention. Detailed Description of the Invention

[0006] However, the thermally conductive silicone grease of the above-mentioned prior art has a problem of dripping when held vertically. In addition, greases that improve drop resistance by using ethylene-propylene copolymers have been reported, but there is a problem that the viscosity is higher than that of greases that use silicone. In addition, silicone and ethylene-propylene copolymers have been mixed to improve drop resistance and have a relatively low viscosity, but a grease with better dischargeability has been desired.

[0007] In order to solve the above-mentioned problems of the conventional art, the present invention provides a thermally conductive silicone resin composition that has high thermal conductivity, is relatively resistant to dripping, and has good dischargeability.

[0008] The present invention provides a thermally conductive silicone resin composition comprising a matrix resin component (A) and thermally conductive inorganic particles (B), The matrix resin component (A) contains, relative to 100 parts by mass of the matrix resin component (A), 70 to 99 parts by mass of liquid dimethylpolysiloxane (A1), A mixed oil (A2) of polydecene and an ethylene-propylene copolymer is contained in an amount of 1 to 30 parts by mass, The liquid dimethylpolysiloxane (A1) has a kinetic viscosity at 40° C. of 50 to 10,000 mm 2 / s, The mixed oil (A2) has a kinetic viscosity at 40°C of 1 to 1,000 mm 2 / s, The thermally conductive silicone resin composition contains 400 to 3,000 parts by mass of the thermally conductive inorganic particles (B) based on 100 parts by mass of the matrix resin component (A).

[0009] The present invention provides a thermally conductive silicone resin composition having high thermal conductivity, relatively little dripping, and good dischargeability, by using the above-mentioned configuration. That is, by using a thermally conductive silicone resin composition containing a liquid dimethylpolysiloxane (A1) of a specific viscosity as the matrix resin component (A) and a mixed oil (A2) of polydecene and an ethylene-propylene copolymer, and containing 400 to 3000 parts by mass of the thermally conductive inorganic particles (B) per 100 parts by mass of the matrix resin component (A), a thermally conductive silicone resin composition having high thermal conductivity, relatively little dripping, and good dischargeability can be provided.

[0010] The thermally conductive silicone resin composition of the present invention contains a matrix resin component (A) and thermally conductive inorganic particles (B).

[0011] <Matrix resin component (A)> The matrix resin component (A) contains 70 to 99 parts by mass of liquid dimethylpolysiloxane (A1) and 1 to 30 parts by mass of a mixed oil (A2) of polydecene and an ethylene-propylene copolymer, relative to 100 parts by mass of the matrix resin component (A).

[0012] (i) Liquid dimethylpolysiloxane (A1) The liquid dimethylpolysiloxane (A1) has a kinetic viscosity at 40° C. of 50 to 10,000 mm 2 / s, preferably 60 to 9,000 mm 2 / s, and more preferably 70 to 8,000 mm 2 By using such a liquid dimethylpolysiloxane (A1), it is possible to obtain a thermally conductive silicone resin composition that has high thermal conductivity, is relatively resistant to dripping, and has good dischargeability.

[0013] The content of the liquid dimethylpolysiloxane (A1) is 70 to 99 parts by mass, preferably 71 to 98 parts by mass, and more preferably 72 to 98 parts by mass, based on 100 parts by mass of the matrix resin component (A).

[0014] (ii) Polydecene and ethylene-propylene copolymer mixed oil (A2) The kinematic viscosity of the mixed oil (A2) of polydecene and ethylene-propylene copolymer at 40°C is 1 to 1,000 mm 2 / s, preferably 5 to 900 mm 2 / s, and more preferably 10 to 800 mm 2 / s. By using such mixed oil (A2), it is possible to obtain a thermally conductive silicone resin composition that has high thermal conductivity, is relatively resistant to dripping, and has good dischargeability. The mixed oil (A2) of polydecene and ethylene-propylene copolymer is a hydrocarbon-based synthetic oil that does not contain a polar group, and is commercially available from Mitsui Chemicals, Inc. under the trade name "Lucant" HC-10. This mixed oil (A2) has a specific gravity of 0.83 (density of 0.83 g / cm 3 The inclusion of this mixed oil (A2) has the advantage of reducing the specific gravity of the thermally conductive silicone resin composition. In addition, the use of such a mixed oil (A2) makes it possible to obtain a thermally conductive silicone resin composition that has high thermal conductivity, is relatively resistant to dripping, and has good dischargeability.

[0015] The content of the mixed oil (A2) is 1 to 30 parts by mass, preferably 2 to 29 parts by mass, and more preferably 3 to 28 parts by mass, based on 100 parts by mass of the matrix resin component (A).

[0016] The mixed oil (A2) preferably contains 30 to 99 mass % of polydecene and 1 to 70 mass % of ethylene-propylene copolymer, more preferably contains 35 to 95 mass % of polydecene and 5 to 65 mass % of ethylene-propylene copolymer, and even more preferably contains 40 to 90 mass % of polydecene and 10 to 60 mass % of ethylene-propylene copolymer, relative to 100 mass % of mixed oil (A2).

[0017] <Thermal conductive inorganic particles (B)> The thermally conductive inorganic particles (B) preferably include thermally conductive inorganic particles (B1) having a median particle size (D50) of 0.01 to 10 μm, thermally conductive inorganic particles (B2) having a median particle size (D50) of more than 10 μm and not more than 80 μm, and thermally conductive inorganic particles (B3) having a median particle size (D50) of more than 80 μm and not more than 150 μm. By using thermally conductive inorganic particles (B) having such a configuration, the thermally conductive inorganic particles (B) can be packed in the thermally conductive silicone resin composition in a state close to close packing, and as a result, the thermal conductivity of the thermally conductive silicone resin composition can be increased. The median particle size is the D50 (median diameter) of the cumulative particle size distribution based on volume measured by a laser diffraction light scattering method. An example of this measuring device is the LA-950S2 laser diffraction / scattering type particle size distribution measuring device manufactured by Horiba, Ltd.

[0018] The thermally conductive inorganic particles (B1) are preferably amorphous alumina. This is because alumina is inexpensive. The thermally conductive inorganic particles (B2) are preferably at least one inorganic particle selected from the group consisting of alumina, zinc oxide, magnesium oxide, aluminum nitride, boron nitride, aluminum hydroxide, and silicon carbide. The thermally conductive inorganic particles (B2) are preferably amorphous. The thermally conductive inorganic particles (B3) are preferably spherical alumina. When the proportion of spherical alumina added as the thermally conductive inorganic particles (B3) is high, the thermal conductivity of the thermally conductive silicone resin composition can be increased and the cost can be reduced. In addition, when alumina is used as the thermally conductive inorganic particles (B), it is preferable to use a combination of so-called submicron particles (B1-1) having a D50 (median diameter) of 0.01 μm or more and less than 1 μm, small particles (B1-2) having a D50 (median diameter) of 1 μm or more and 10 μm or less, and large particles (B3) having a D50 of more than 80 μm and 150 μm or less. By using thermally conductive inorganic particles (B) of such a configuration, the thermally conductive inorganic particles (B) can be closely packed in the thermally conductive silicone resin composition, and as a result, the thermal conductivity of the thermally conductive silicone resin composition can be increased. In addition, the amorphous alumina is produced by pulverization or crushing, and a commercially available product can be used. These thermally conductive inorganic particles (B1), (B2) and (B3) have high thermal conductivity.

[0019] The mass ratio of the thermally conductive inorganic particles (B1), (B2), and (B3) is preferably (B2)≦(B1)≦(B3), because by satisfying this ratio, the thermally conductive inorganic particles can be packed in a state close to close-packed in the thermally conductive silicone resin composition, thereby increasing the thermal conductivity of the thermally conductive silicone resin composition.

[0020] The thermally conductive inorganic particles (B) preferably contain 100 to 1,000 parts by mass of the thermally conductive inorganic particles (B1) relative to 100 parts by mass of the matrix resin component (A), more preferably 150 to 1,000 parts by mass, and even more preferably 300 to 850 parts by mass. The thermally conductive inorganic particles (B) preferably contain 100 to 500 parts by mass of the thermally conductive inorganic particles (B2) relative to 100 parts by mass of the matrix resin component (A), more preferably 150 to 500 parts by mass, and even more preferably 200 to 450 parts by mass. The thermally conductive inorganic particles (B) preferably contain 300 to 1,400 parts by mass of the thermally conductive inorganic particles (B3) relative to 100 parts by mass of the matrix resin component (A), more preferably 300 to 1,300 parts by mass, and even more preferably 500 to 1,200 parts by mass. This makes it possible to obtain a thermally conductive silicone resin composition that has high thermal conductivity, is relatively resistant to dripping, and has good dischargeability. For the same reason, the thermally conductive inorganic particles (B) preferably contain 100 to 1,000 parts by mass of the thermally conductive inorganic particles (B1), 100 to 500 parts by mass of the thermally conductive inorganic particles (B2), and 300 to 1,400 parts by mass of the thermally conductive inorganic particles (B3) relative to 100 parts by mass of the matrix resin component (A), more preferably contain 150 to 1,000 parts by mass of the thermally conductive inorganic particles (B1), 150 to 500 parts by mass of the thermally conductive inorganic particles (B2), and 300 to 1,300 parts by mass of the thermally conductive inorganic particles (B3), and further preferably contain 300 to 850 parts by mass of the thermally conductive inorganic particles (B1), 200 to 450 parts by mass of the thermally conductive inorganic particles (B2), and 500 to 1,200 parts by mass of the thermally conductive inorganic particles (B3).

[0021] The thermally conductive inorganic particles (B1) having a median particle diameter (D50) of 0.01 to 10 μm, the thermally conductive inorganic particles (B2) having a median particle diameter (D50) of more than 10 μm and not more than 80 μm, and the thermally conductive inorganic particles (B3) having a median particle diameter (D50) of more than 80 μm and not more than 150 μm may each contain two or more types of thermally conductive inorganic particles having different median particle diameters (D50). By using the thermally conductive inorganic particles (B) having such a configuration, the thermally conductive inorganic particles (B) can be closely packed in the thermally conductive silicone resin composition, and as a result, the thermal conductivity of the thermally conductive silicone resin composition can be increased. For example, it is preferable that the thermally conductive inorganic particles (B1) contain two or more types of thermally conductive inorganic particles having different median particle diameters (D50). Specifically, the thermally conductive inorganic particles (B1) preferably include thermally conductive inorganic particles (B1-1) having a median particle size (D50) of 0.01 μm or more and less than 1 μm and thermally conductive inorganic particles (B1-2) having a median particle size (D50) of 1 μm or more and 10 μm or less, more preferably include thermally conductive inorganic particles (B1-1) having a median particle size (D50) of 0.05 μm or more and less than 1 μm and thermally conductive inorganic particles (B1-2) having a median particle size (D50) of 1 μm or more and 8 μm or less, and even more preferably include thermally conductive inorganic particles (B1-1) having a median particle size (D50) of 0.1 μm or more and less than 1 μm and thermally conductive inorganic particles (B1-2) having a median particle size (D50) of 1 μm or more and 5 μm or less. By using thermally conductive inorganic particles (B) having such a configuration, the thermally conductive inorganic particles (B) can be closely packed in the thermally conductive silicone resin composition, and as a result, the thermal conductivity of the thermally conductive silicone resin composition can be increased. When the thermally conductive inorganic particles (B1) contain the thermally conductive inorganic particles (B1-1) and the thermally conductive inorganic particles (B1-2), the thermally conductive inorganic particles (B1) preferably contain 50 to 400 parts by mass of the thermally conductive inorganic particles (B1-1) and 50 to 600 parts by mass of the thermally conductive inorganic particles (B1-2) per 100 parts by mass of the matrix resin component (A), more preferably contain 50 to 400 parts by mass of the thermally conductive inorganic particles (B1-1) and 100 to 600 parts by mass of the thermally conductive inorganic particles (B1-2), and even more preferably contain 100 to 350 parts by mass of the thermally conductive inorganic particles (B1-1) and 200 to 500 parts by mass of the thermally conductive inorganic particles (B1-2).By using thermally conductive inorganic particles (B) having such a configuration, the thermally conductive inorganic particles (B) can be closely packed in the thermally conductive silicone resin composition, and as a result, the thermal conductivity of the thermally conductive silicone resin composition can be increased.

[0022] A part or all of the thermally conductive inorganic particles (B1) having a median particle size (D50) of 0.01 to 10 μm is represented by the formula RaSi(OR') 4-a (wherein R is an unsubstituted or substituted organic group having 8 to 12 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, and a is 0 or 1). Surface treatment in advance means pretreatment before mixing. By surface treating the thermally conductive inorganic particles (B1) in advance, it becomes easier to fill the thermally conductive inorganic particles (B1) into the matrix resin component (A), and it is effective in preventing the curing catalyst (e.g., platinum-based catalyst) from being adsorbed to the thermally conductive inorganic particles (B1), thereby preventing curing inhibition. This is useful for storage stability. In particular, small particles having a D50 (median diameter) of 10 μm or less tend to adsorb the curing catalyst, so it is preferable to surface treat the thermally conductive inorganic particles having a D50 (median diameter) of 10 μm or less. The surface treatment here includes adsorption as well as covalent bonding. The surface-treated thermally conductive inorganic particles (B1) have good mixability with the matrix resin component (A). The alkoxysilane is preferably added in an amount of 0.01 to 10 parts by mass per 100 parts by mass of the thermally conductive inorganic particles.

[0023] Examples of the alkoxysilane include octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, and dodecyltriethoxysilane. The alkoxysilane may be used alone or in combination of two or more. As the surface treatment agent, an alkoxysilane and a siloxane having a silanol end at one end may be used in combination.

[0024] The content of the thermally conductive inorganic particles (B) is 400 to 3,000 parts by mass, preferably 500 to 2,900 parts by mass, and more preferably 600 to 2,800 parts by mass, based on 100 parts by mass of the matrix resin component (A).

[0025] <Thermal conductive silicone resin composition> The thermally conductive silicone resin composition is produced by mixing the matrix resin component (A) with the thermally conductive inorganic particles (B) and, if necessary, other components.

[0026] The thermally conductive silicone resin composition further contains, as a viscosity modifier, a compound of the formula RaSi(OR') 4-a (wherein R is an unsubstituted or substituted organic group having 8 to 12 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, and a is 0 or 1), and this is because the dischargeability of the thermally conductive silicone resin composition is further improved.

[0027] Examples of the alkoxysilane include octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, and dodecyltriethoxysilane. The alkoxysilane may be used alone or in combination of two or more. As the surface treatment agent, an alkoxysilane and a siloxane having a silanol end at one end may be used in combination.

[0028] The thermal conductivity of the thermally conductive silicone resin composition is preferably 1.0 W / m K or more, more preferably 1.0 to 10 W / m K, and even more preferably 1.5 to 9 W / m K. Such a thermally conductive silicone resin composition is suitable as a heat sink: TIM (Thermal Interface Material) between heat generating parts and heat dissipating parts of electronic components, etc.

[0029] The thermally conductive silicone resin composition has an absolute viscosity at 23°C measured with a B-type viscometer at a rotation speed of 5 rpm using a TE spindle, preferably in the range of 1,000 to 20,000 Pa·s, more preferably 1,000 to 18,000 Pa·s, and even more preferably 1,000 to 15,000 Pa·s. Such a thermally conductive silicone resin composition has good dischargeability. In addition, such a thermally conductive silicone resin composition has excellent workability and is also good injectability (dischargeability) or applicability between a heat generating part and a heat dissipating part.

[0030] The thermally conductive silicone resin composition is preferably in a heat shock test in which 1.0 g of the thermally conductive silicone resin composition is placed between two plates, the thermally conductive silicone resin composition is compressed and sandwiched between the two plates so that the thickness of the layer made of the thermally conductive silicone resin composition is 1.0 mm, the main surface of the plate is perpendicular to the ground, and the plates are held in a heat shock tester, and then the plate is held at -40°C for 30 minutes, heated, and then held at 125°C for 30 minutes, and then cooled to -40°C. In the heat shock test, which is performed for 500 or 100 cycles, the drop of the thermally conductive silicone resin composition from the start of the test is preferably within 5 mm. This makes it possible to increase the drop resistance and make it difficult to drip. In both the heat shock test performed for 500 or 100 cycles, it is more preferable that the drop of the thermally conductive silicone resin composition from the start of the test is within 5 mm.

[0031] The thermally conductive silicone resin composition is filled into a 30 mL syringe, and when discharged for 9 seconds with a discharge hole diameter of 2.5 mm and a discharge pressure of 0.5 MPa, the discharge amount is preferably 2 to 10 g, more preferably 2 to 9 g, and even more preferably 2 to 8 g. This allows the thermally conductive silicone resin composition to have high drop resistance and good dischargeability while being less likely to drip.

[0032] The thermally conductive silicone resin composition of the present invention can be used in the form of grease, putty, or liquid, but is preferably a thermally conductive grease. When the thermally conductive silicone resin composition of the present invention is a thermally conductive grease, the thermally conductive grease is suitable for filling a syringe and applying to a heat sink (TIM (Thermal Interface Material)) between a heat generating part and a heat dissipating part of an electronic component or the like.

[0033] The thermally conductive silicone resin composition of the present invention is in an uncured or non-cured state, and therefore does not require a curing catalyst or a curing agent, although they may be added in some cases.

[0034] The thermally conductive silicone resin composition of the present invention may contain other components as necessary. For example, a heat resistance improver such as red iron oxide, titanium oxide, or cerium oxide, a flame retardant, or a flame retardant assistant may be added to the thermally conductive silicone resin composition. In addition, an organic or inorganic particle pigment may be added to the thermally conductive silicone resin composition for the purpose of coloring or color matching. An alkoxy group-containing silicone may be added to the thermally conductive silicone resin composition as a material added for the purpose of filler surface treatment or the like.

[0035] The thermally conductive silicone resin composition of the present invention can be filled into dispensers, bottles, cans, tubes, and the like to produce commercial products.

[0036] The present invention includes the following aspects.

[0037] [Section 1] A thermally conductive silicone resin composition comprising a matrix resin component (A) and thermally conductive inorganic particles (B), The matrix resin component (A) contains, relative to 100 parts by mass of the matrix resin component (A), 70 to 99 parts by mass of liquid dimethylpolysiloxane (A1), A mixed oil (A2) of polydecene and an ethylene-propylene copolymer is contained in an amount of 1 to 30 parts by mass, The liquid dimethylpolysiloxane (A1) has a kinetic viscosity at 40° C. of 50 to 10,000 mm 2 / s, The mixed oil (A2) has a kinetic viscosity at 40°C of 1 to 1,000 mm 2 / s, A thermally conductive silicone resin composition comprising 400 to 3,000 parts by mass of the thermally conductive inorganic particles (B) per 100 parts by mass of the matrix resin component (A).

[0038] [Section 2] The liquid dimethylpolysiloxane (A1) preferably has a kinetic viscosity at 40° C. of 60 to 9,000 mm 2 / s, and more preferably 70 to 8,000 mm 2 Item 2. The thermally conductive silicone resin composition according to item 1, wherein the thermally conductive silicone resin composition has a molecular weight of 1 / s.

[0039] [Section 3] 3. The thermally conductive silicone resin composition according to item 1 or 2, wherein the content of the liquid dimethylpolysiloxane (A1) is preferably 71 to 98 parts by mass, and more preferably 72 to 98 parts by mass, per 100 parts by mass of the matrix resin component (A).

[0040] [Section 4] The kinematic viscosity of the mixed oil (A2) at 40° C. is preferably 5 to 900 mm 2 / s, and more preferably 10 to 800 mm 2 4. The thermally conductive silicone resin composition according to any one of items 1 to 3, wherein R 1 is 0.1 to 0.5;

[0041] [Section 5] 5. The thermally conductive silicone resin composition according to any one of items 1 to 4, wherein the content of the mixed oil (A2) is preferably 2 to 29 parts by mass, and more preferably 3 to 28 parts by mass, relative to 100 parts by mass of the matrix resin component (A).

[0042] [Section 6] Item 6. The thermally conductive silicone resin composition according to any one of Items 1 to 5, preferably containing 30 to 99 mass% of polydecene and 1 to 70 mass% of an ethylene-propylene copolymer, more preferably containing 35 to 95 mass% of polydecene and 5 to 65 mass% of an ethylene-propylene copolymer, and even more preferably containing 40 to 90 mass% of polydecene and 10 to 60 mass% of an ethylene-propylene copolymer, relative to 100 mass% of the mixed oil (A2).

[0043] [Section 7] Further, the formula RaSi(OR') 4-a (wherein R is an unsubstituted or substituted organic group having 8 to 12 carbon atoms, R′ is an alkyl group having 1 to 4 carbon atoms, and a is 0 or 1).

[0044] [Section 8] Item 8. The thermally conductive silicone resin composition according to any one of items 1 to 7, wherein the alkoxysilane is at least one selected from the group consisting of octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, and dodecyltriethoxysilane.

[0045] [Section 9] The thermally conductive inorganic particles (B) are Thermally conductive inorganic particles (B1) having a median particle size (D50) of 0.01 to 10 μm; Thermally conductive inorganic particles (B2) having a median particle size (D50) of more than 10 μm and not more than 80 μm; Thermally conductive inorganic particles (B3) with a median particle size (D50) of more than 80 μm and less than 150 μm 9. The thermally conductive silicone resin composition according to any one of items 1 to 8, comprising:

[0046] [Section 10] 10. The thermally conductive silicone resin composition according to any one of items 1 to 9, wherein the thermally conductive inorganic particles (B1) are preferably amorphous alumina.

[0047] [Section 11] The thermally conductive silicone resin composition according to any one of items 1 to 10, wherein the thermally conductive inorganic particles (B2) are preferably at least one inorganic particle selected from the group consisting of alumina, zinc oxide, magnesium oxide, aluminum nitride, boron nitride, aluminum hydroxide, and silicon carbide, and more preferably amorphous aluminum nitride.

[0048] [Section 12] 12. The thermally conductive silicone resin composition according to any one of items 1 to 11, wherein the thermally conductive inorganic particles (B3) are preferably spherical alumina.

[0049] [Section 13] 13. The thermally conductive silicone resin composition according to any one of items 9 to 12, wherein the mass ratio of the thermally conductive inorganic particles (B1), (B2), and (B3) is expressed as (B2)≦(B1)≦(B3).

[0050] [Section 14] A part or all of the thermally conductive inorganic particles (B1) are represented by the formula RaSi(OR') 4-a (wherein R is an unsubstituted or substituted organic group having 8 to 12 carbon atoms, R′ is an alkyl group having 1 to 4 carbon atoms, and a is 0 or 1).

[0051] [Section 15] Item 15. The thermally conductive silicone resin composition according to any one of items 9 to 14, wherein the alkoxysilane is at least one selected from the group consisting of octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, and dodecyltriethoxysilane.

[0052] [Section 16] The thermally conductive inorganic particles (B) preferably contain 100 to 1,000 parts by mass, more preferably 150 to 1,000 parts by mass, and further preferably 300 to 850 parts by mass of the thermally conductive inorganic particles (B1) per 100 parts by mass of the matrix resin component (A).

[0053] [Section 17] The thermally conductive inorganic particles (B) preferably contain 100 to 500 parts by mass, more preferably 150 to 500 parts by mass, and further preferably 200 to 450 parts by mass of the thermally conductive inorganic particles (B2) per 100 parts by mass of the matrix resin component (A).

[0054] [Section 18] The thermally conductive inorganic particles (B) contain preferably 300 to 1,400 parts by mass, more preferably 300 to 1,300 parts by mass, and further preferably 500 to 1,200 parts by mass of the thermally conductive inorganic particles (B3) per 100 parts by mass of the matrix resin component (A).

[0055] [Section 19] Item 19. The thermally conductive silicone resin composition according to any one of items 9 to 18, wherein the thermally conductive inorganic particles (B1) preferably contain two or more types of thermally conductive inorganic particles having different median particle sizes (D50).

[0056] [Section 20] The thermally conductive inorganic particles (B1) are Preferably, the thermally conductive inorganic particles (B1-1) have a median particle size (D50) of 0.01 μm or more and less than 1 μm, and the thermally conductive inorganic particles (B1-2) have a median particle size (D50) of 1 μm or more and 10 μm or less, More preferably, the thermally conductive inorganic particles (B1-1) have a median particle size (D50) of 0.05 μm or more and less than 1 μm, and the thermally conductive inorganic particles (B1-2) have a median particle size (D50) of 1 μm or more and 8 μm or less, More preferably, the thermally conductive silicone resin composition according to item 19 contains thermally conductive inorganic particles (B1-1) having a median particle size (D50) of 0.1 μm or more and less than 1 μm, and thermally conductive inorganic particles (B1-2) having a median particle size (D50) of 1 μm or more and 5 μm or less.

[0057] [Section 21] The thermally conductive inorganic particles (B1) are mixed in an amount of 100 parts by mass of the matrix resin component (A), Preferably, the thermally conductive inorganic particles (B1-1) are contained in an amount of 50 to 400 parts by mass, and the thermally conductive inorganic particles (B1-2) are contained in an amount of 50 to 600 parts by mass, More preferably, the thermally conductive inorganic particles (B1-1) are contained in an amount of 50 to 400 parts by mass, and the thermally conductive inorganic particles (B1-2) are contained in an amount of 100 to 600 parts by mass, More preferably, the thermally conductive silicone resin composition according to item 20 contains 100 to 350 parts by mass of the thermally conductive inorganic particles (B1-1) and 200 to 500 parts by mass of the thermally conductive inorganic particles (B1-2).

[0058] [Section 22] 22. The thermally conductive silicone resin composition according to any one of items 1 to 21, wherein the content of the thermally conductive inorganic particles (B) is preferably 500 to 2900 parts by mass, more preferably 600 to 2800 parts by mass, per 100 parts by mass of the matrix resin component (A).

[0059] [Section 23] 23. The thermally conductive silicone resin composition according to any one of items 1 to 22, wherein the thermal conductivity is preferably 1.0 W / m·K or more, more preferably 1.0 to 10 W / m·K, and even more preferably 1.5 to 9 W / m·K.

[0060] [Section 24] 24. The thermally conductive silicone resin composition according to any one of items 1 to 23, wherein the absolute viscosity at 23° C. as measured with a Brookfield viscometer is preferably in the range of 1,000 to 20,000 Pa s, more preferably 1,000 to 18,000 Pa s, and even more preferably 1,000 to 15,000 Pa s.

[0061] [Section 25] 1.0 g of the thermally conductive silicone resin composition is placed between two plates, and the two plates are in a state where the thermally conductive silicone resin composition is compressed and sandwiched between them so that the thickness of the layer made of the thermally conductive silicone resin composition is 1.0 mm. In this state, the two plates are held in a heat shock tester so that the main surfaces of the plates are perpendicular to the ground. Then, the plate is held at -40°C for 30 minutes, the temperature is increased, and then the plate is held at 125°C for 30 minutes, and the temperature is decreased to -40°C. In this heat shock test, 500 or 100 cycles of this cycle are performed, and the thermally conductive silicone resin composition falls within 5 mm from the start of the test. 25. The thermally conductive silicone resin composition according to any one of items 1 to 24, wherein the drop of the thermally conductive silicone resin composition from the start of a heat shock test of 500 cycles or 100 cycles is within 5 mm.

[0062] [Section 26] 26. The thermally conductive silicone resin composition according to any one of items 1 to 25, wherein the amount of the composition discharged when filled into a 30 mL syringe and discharged for 9 seconds at a discharge hole diameter of 2.5 mm and a discharge pressure of 0.5 MPa is preferably 2 to 10 g, more preferably 2 to 9 g, and even more preferably 2 to 8 g.

[0063] [Section 27] 27. The thermally conductive silicone resin composition according to any one of items 1 to 26, which is a thermally conductive grease.

[0064] [Section 28] 28. The thermally conductive silicone resin composition according to any one of items 1 to 27, which is in an uncured state or in a cured state.

[0065] [Example] The present invention will be described below with reference to examples, but is not limited to these examples. Various parameters were measured by the following methods.

[0066] <Thermal conductivity> The thermal conductivity of the thermally conductive silicone resin composition was measured by a hot disk (ISO 22007-2:2008 compliant). As shown in FIG. 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, and generates constant heat to analyze the thermal characteristics from the temperature rise value of the sensor 2. The sensor 2 has a tip 4 with a diameter of 7 mm, and as shown in FIG. 1B, has a double spiral electrode structure, with an applied current electrode 5 and a resistance value electrode (temperature measurement electrode) 6 arranged at the bottom. The measurement sample can be obtained by rolling and molding the degassed thermally conductive liquid composition to a thickness of 7 mm or more. The thermal conductivity is calculated by the following formula (Mathematical formula 1).

[0067]

number

[0068] <Absolute Viscosity of Thermally Conductive Silicone Resin Composition> The absolute viscosity of the thermally conductive silicone resin composition was measured using a Brookfield type viscometer (HBDV2T manufactured by Brookfield Instruments Inc.) The absolute viscosity was measured at a rotation speed of 5 rpm and 23° C. using a TE spindle.

[0069] <Drop test> This was measured using the drop test shown in Figures 2A-D. 1.0 g of the thermally conductive silicone resin composition 14 was applied to an aluminum plate 12 having a length of 40 mm, a width of 100 mm, and a thickness of 5 mm (FIG. 2A), and the aluminum plate and a glass plate 11 having a length of 40 mm, a width of 100 mm, and a thickness of 5 mm were sandwiched between them with a spacer 13 so that the thickness of the thermally conductive silicone resin composition was 1.0 mm (FIG. 2B). In FIG. 2B, 15 is the thermally conductive silicone resin composition compressed to a thickness of 1.0 mm. Next, the aluminum plate 12 and the glass plate 11 were placed in a heat cycle tester so that the main surfaces of the plate were perpendicular to the ground (FIG. 2C). In FIG. 2C, 16 is the test piece before the test. In this state, a heat cycle test was performed in which the plate was held at -40°C for 30 minutes, heated to 125°C, held at 125°C for 30 minutes, and cooled to -40°C for 100 cycles and 500 cycles. After 100 cycles and 500 cycles, the test piece was removed and observed to see if the thermally conductive silicone resin composition 15 had fallen. 17 is the test piece after the test (FIG. 2D), and 18 is the fall distance.

[0070] Evaluation criteria A: The falling distance of the thermally conductive silicone resin composition was within 5 mm. B: The falling distance of the thermally conductive silicone resin composition exceeded 5 mm.

[0071] <Discharge test> The thermally conductive silicone resin composition was filled into a 30 mL syringe PSY-30F manufactured by Musashi Engineering Co., Ltd., and the amount discharged was measured when the composition was discharged for 9 seconds with a discharge hole diameter of 2.5 mm and a discharge pressure of 0.5 MPa.

[0072] (Examples 1 to 3, Comparative Examples 1 to 3) 1. Raw material ingredients (1) Matrix resin component (A) Liquid dimethylpolysiloxane (A1): Dynamic viscosity at 40°C is 110mm 2 / s liquid dimethyl silicone oil, specific gravity 0.97g / cm 3 Manufactured by Dow Toray, product name "SH200CV 110CS" Polydecene and ethylene-propylene copolymer mixed oil (A2): Kinematic viscosity at 40°C is 100mm 2 / s, Mitsui Chemicals, product name "Lucant" HC-10 (polydecene content 50-80 mass%), specific gravity 0.83 g / cm 3 Ethylene-propylene copolymer oil: kinematic viscosity at 40°C is 200mm 2 / s, Mitsui Chemicals, product name "Lucant" HC-20, specific gravity 0.83g / cm 3

[0073] (2) Thermally conductive inorganic particles (B) Irregular alumina (B1) with a median particle size of 0.3 μm (D50 = 0.3 μm) (Figure 3): Octyltrimethoxysilane pre-treated product (2.4 g of octyltrimethoxysilane was adsorbed to 100 g of alumina), specific gravity 3.98 g / cm 3 Irregular alumina (B1) with a median particle size of 2.3 μm (D50 = 2.3 μm) (Figure 4): Decyltrimethoxysilane pre-treated product (1.1 g of decyltrimethoxysilane was adsorbed to 100 g of alumina), specific gravity 3.98 g / cm 3 - Irregular shaped aluminum nitride (B2) (Fig. 5) with a median particle size of 15 μm (D50 = 15 μm) (no surface treatment), specific gravity 3.26 g / cm 3 Spherical alumina (B3) (Fig. 6) with a median particle size of 105 μm (D50 = 105 μm) (no surface treatment), specific gravity 3.98 g / cm 3 The blending amounts are shown in Table 1.

[0074] (3) Viscosity modifier (C) Decyltrimethoxysilane, specific gravity 0.90g / cm 3 2.Mixing method The above matrix resin component (A) was mixed with thermally conductive inorganic particles (B) and a viscosity modifier so as to obtain the composition shown in Table 1 below, thereby producing a thermally conductive silicone resin composition. The thermally conductive silicone resin compositions obtained as described above were evaluated. The compositions and results are summarized in Table 1 below.

[0075] [Table 1]

[0076] From the above results, the following can be seen: (1) Example 1 has better ejection properties than Comparative Example 2. (2) Example 2 has better ejection properties than Comparative Example 3, and does not fall even after 500 cycles of drop test. (3) Drop resistance is also exhibited in Example 3, in which a small amount of mixed oil (A2) is blended. (4) Comparative Example 1, which does not contain the mixed oil (A2), shows poor results in the drop test. (5) In Comparative Example 2, in which ethylene-propylene copolymer oil was used instead of the mixed oil (A2), the drop test results were good, but the dischargeability was poor compared to Example 1. (6) Comparative Example 3, in which the amount of oil blended in the ethylene-propylene copolymer was reduced, exhibited poor results in the drop test. (7) Overall, it was confirmed that, compared with Comparative Examples 1 to 3, Examples 1 to 3 were able to provide thermally conductive silicone resin compositions that had high thermal conductivity, were relatively less likely to drip, and had good dischargeability.

[0077] The thermally conductive silicone resin composition of the present invention is suitable for use between a heat-generating portion of an electric or electronic part and a heat sink. [Explanation of symbols]

[0078] 1. Thermal conductivity measuring device 2 Sensors 3a,3b Sample 4 Sensor tip 5 Electrode for applied current 6 Resistance electrodes (temperature measurement electrodes) 11 Glass Plate 12 Aluminum plate 13 Spacer 14. Thermally conductive silicone resin composition 15 Compressed thermally conductive silicone resin composition 16 Test specimen before testing 17 Test piece after test 18 Fall Distance

Claims

1. A thermally conductive silicone resin composition comprising a matrix resin component (A) and thermally conductive inorganic particles (B), The matrix resin component (A) contains, relative to 100 parts by mass of the matrix resin component (A), 70 to 99 parts by mass of liquid dimethylpolysiloxane (A1), A mixed oil (A2) of polydecene and an ethylene-propylene copolymer is contained in an amount of 1 to 30 parts by mass, The liquid dimethylpolysiloxane (A1) has a kinetic viscosity at 40° C. of 50 to 10,000 mm 2 / s, The mixed oil (A2) has a kinetic viscosity at 40° C. of 1 to 1,000 mm 2 / s, A thermally conductive silicone resin composition comprising 400 to 3,000 parts by mass of the thermally conductive inorganic particles (B) per 100 parts by mass of the matrix resin component (A).

2. 2. The thermally conductive silicone resin composition according to claim 1, comprising, relative to 100 mass% of the mixed oil (A2), 30 to 99 mass% of polydecene and 1 to 70 mass% of an ethylene-propylene copolymer.

3. The thermally conductive resin composition further has the formula RaSi(OR') 4-a (wherein R is an unsubstituted or substituted organic group having 8 to 12 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, and a is 0 or 1).

4. The thermally conductive inorganic particles (B) are Thermally conductive inorganic particles (B1) having a median particle size (D50) of 0.01 to 10 μm; Thermally conductive inorganic particles (B2) having a median particle size (D50) of more than 10 μm and not more than 80 μm; Thermally conductive inorganic particles (B3) having a median particle size (D50) of more than 80 μm and not more than 150 μm The thermally conductive silicone resin composition according to claim 1 , comprising:

5. 5. The thermally conductive silicone resin composition according to claim 4, wherein the mass ratios of the thermally conductive inorganic particles (B1), (B2), and (B3) are expressed as (B2)≦(B1)≦(B3).

6. A part or all of the thermally conductive inorganic particles (B1) are represented by the formula RaSi(OR') 4-a (wherein R is an unsubstituted or substituted organic group having 8 to 12 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, and a is 0 or 1).

7. 2. The thermally conductive silicone resin composition according to claim 1, wherein the thermal conductivity of the thermally conductive silicone resin composition is 1.0 W / m·K or more.

8. 2. The thermally conductive silicone resin composition according to claim 1, wherein the thermally conductive silicone resin composition has an absolute viscosity at 23° C. measured with a B-type viscometer in the range of 1,000 to 20,000 Pa·s.

9. 2. The thermally conductive silicone resin composition according to claim 1, wherein 1.0 g of the thermally conductive silicone resin composition is placed between two plates, the two plates are compressed and sandwiched between the two plates so that the thickness of a layer made of the thermally conductive silicone resin composition is 1.0 mm, and the plates are held in a heat shock tester so that the main surfaces of the plates are perpendicular to the ground. The heat shock test is then performed for 500 cycles, in which the heat conductive silicone resin composition is held at -40°C for 30 minutes, then heated, and then held at 125°C for 30 minutes, and then cooled to -40°C. In the heat shock test, the heat conductive silicone resin composition falls by 5 mm or less from the start of the test.

10. The thermally conductive silicone resin composition according to claim 1, wherein the amount of the composition discharged when the composition is filled into a 30 mL syringe and discharged for 9 seconds at a discharge hole diameter of 2.5 mm and a discharge pressure of 0.5 MPa is 2 to 10 g.

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

12. The thermally conductive silicone resin composition according to claim 1 , wherein the thermally conductive silicone resin composition is in an uncured state or in a cured state.

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