Thermally conductive silicone composition

Abstract

A thermally conductive silicone composition, which has an organopolysiloxane as a base polymer, and contains a thermally conductive filler, the base polymer including a fluorine-free organopolysiloxane and a fluorine-containing organopolysiloxane, the thermally conductive silicone composition being cured by an addition-curing catalyst, the number of fluorine groups in the constituent components of the base polymer relative to the total number of alkenyl groups bonded to silicon atoms in the constituent components of the base polymer being 2.00 or greater and 30.0 or less.

Description

Technical Field

[0001] The present invention relates to a thermally conductive organosilicon composition suitable for sandwiching between a heat-generating part and a heat sink in electrical or electronic components, etc. Background Technology

[0002] In recent years, thermally conductive materials containing silicone rubber, used in heat-generating components of electronic parts such as CPUs and power transistors, have seen increased application in the automotive industry due to their excellent heat resistance, weather resistance, and electrical insulation. However, silicone rubber is prone to swelling or deterioration when exposed to solvents such as toluene or gasoline. Therefore, it presents a problem of difficulty in maintaining performance when exposed to environments such as ATF (automotive fuel oil).

[0003] Patent documents 1 and 2 disclose compositions obtained by adding thermally conductive fillers to polyorganosiloxanes containing highly oil-resistant fluorine in the main chain or side chains. Furthermore, patent document 3 discloses a method of blending cured fluororubber with cured silicone rubber and then curing it again.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-82090

[0007] Patent Document 2: Japanese Patent Publication No. 63-67335

[0008] Patent Document 3: Japanese Patent Application Publication No. 2006-161032 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, the silicone compositions in Patent Documents 1 and 2 have the problem of high cost of fluorinated polysiloxanes. In addition, the silicone composition in Patent Document 3 involves two curing reactions, which makes the process complicated and costly. Furthermore, since the cured rubbers are blended together, there are few chemical bonds, making it difficult to apply to heat-resistant applications.

[0011] In order to solve the above-mentioned problems, the present invention provides a thermally conductive organosilicon composition that reduces the content of fluorinated organopolysiloxanes, lowers costs, and exhibits oil resistance.

[0012] Methods for solving problems

[0013] The thermally conductive organosilicon composition of the present invention is a thermally conductive organosilicon composition with organopolysiloxane as the base polymer and containing a thermally conductive filler. The base polymer includes fluorine-free organopolysiloxane and fluorine-containing organopolysiloxane. The thermally conductive organosilicon composition is cured by an addition-curing catalyst. The ratio of the number of fluorine groups in the constituent components of the base polymer to the total number of alkenyl groups bonded to silicon atoms in the constituent components of the base polymer is 2.00 or more and 30.0 or less.

[0014] The method for manufacturing the thermally conductive silicone gel sheet of the present invention includes:

[0015] A composition containing a base polymer comprising both fluorine-free and fluorine-containing organopolysiloxanes, an addition-curing catalyst, and a thermally conductive filler is uniformly mixed, formed into a sheet, and then thermosetting.

[0016] The ratio of the number of fluorine groups in the constituent components of the aforementioned basic polymer to the total number of alkenyl groups bonded to silicon atoms in the constituent components of the aforementioned basic polymer is 2.00 or more and 30.0 or less.

[0017] Invention Effects

[0018] The present invention contains both fluorine-free and fluorine-containing organopolysiloxanes in the base polymer in such a way that the ratio of the number of fluorine groups to the total number of alkenes bonded to silicon atoms is 2.00 or more and 30.0 or less. Therefore, it is possible to provide a thermally conductive organosilicon composition that reduces the content of fluorine-containing organopolysiloxanes, thereby reducing costs, and exhibiting oil resistance. Attached Figure Description

[0019] Figure 1 of Figure 1 AB is an explanatory diagram illustrating a method for measuring the thermal conductivity of a sample in one embodiment of the present invention. Detailed Implementation

[0020] This invention relates to a thermally conductive silicone composition, which uses an organopolysiloxane as a base polymer and contains a thermally conductive filler. The base polymer comprises a fluorine-free organopolysiloxane and a fluorine-containing organopolysiloxane. They are known as silicone gel materials or silicone rubber materials, respectively. The above-mentioned thermally conductive silicone composition is cured by an addition-curing catalyst. The ratio of the total number of fluorine groups in the constituent components of the above-mentioned base polymer to the total number of alkenes bonded to silicon atoms in the constituent components of the above-mentioned base polymer (fluorine group / alkene group) is 2.00 or more and 30.0 or less, preferably 2.00 or more and 20.0 or less, more preferably 2.50 or more and 18.0 or less. Because the base polymer contains both fluorine-free and fluorine-containing organopolysiloxanes in the above-mentioned ratio range, the cost is reduced, the oil resistance is excellent, and a suitable hardness for use as a thermally conductive material (TIM) can be achieved.

[0021] The content of alkenyl groups bonded to silicon atoms in the constituent components of the above-mentioned basic polymer is preferably 0.010 to 0.013 mol per 100g of basic polymer, more preferably 0.011 to 0.013 mol, and even more preferably 0.012 to 0.013 mol.

[0022] The preferred base polymer is an addition-curing silicone polymer. This polymer has high heat resistance and is useful as a thermally conductive sheet. The base polymer may contain, for example, the following components A1, A2, A3, and B as constituent components.

[0023] A1: A fluorine-free organopolysiloxane having two or more alkenyl groups in one molecule.

[0024] A2: A fluorine-free organopolysiloxane having two Si-H groups in one molecule.

[0025] A3: Fluorine-free organopolysiloxanes having three or more Si-H groups in one molecule.

[0026] B: Fluorinated organopolysiloxanes having two or more alkenyl groups in one molecule.

[0027] Component A3 is a crosslinking component. Because the base polymer contains components A2 and A3, both of which are organopolysiloxanes with more than two Si-H groups, it has the advantages of easy adjustment of hardness and easy improvement of the resilience of cured products.

[0028] The ratio of the total number of Si-H groups in the constituent components of the above-mentioned basic polymer to the total number of alkenes bonded to silicon atoms in the constituent components of the above-mentioned basic polymer (Si-H group number / alkene group number) is preferably 0.6 or more and 1.2 or less, more preferably 0.7 or more and 1.1 or less, and even more preferably 0.8 or more and 1.1 or less.

[0029] The composition ratio of the above-mentioned thermally conductive organosilicon composition is preferably as follows, for example.

[0030] Relative to 100 parts by weight of the total of components A1 and B, it comprises:

[0031] 50-100 parts by weight of component A2

[0032] 0.5 to 2 parts by weight of component A3,

[0033] Addition-curing catalysts with catalytic content

[0034] The thermally conductive filler comprises 100 to 4000 parts by weight of the base polymer relative to 100 parts by weight of the base polymer.

[0035] Regarding the proportions, relative to a total of 100 parts by mass of components A1 and B, component A2 is more preferably 60 to 80 parts by mass, and component A3 is more preferably 0.5 to 1 part by mass. From the viewpoint of improving thermal conductivity, the thermally conductive filler is more preferably contained in 500 to 3700 parts by mass relative to 100 parts by mass of the base polymer. The amount of the addition-curing catalyst is only required for the curing of this composition and can be appropriately adjusted according to the desired curing rate, etc. For example, relative to the total of components A1 and B, it is preferable to add 0.01 to 1000 ppm by atomic weight of metal.

[0036] [Ingredient A1]

[0037] The aforementioned component A1 is a fluorine-free organopolysiloxane having two or more alkenyl groups in one molecule. As an alkenyl group, it is an alkenyl group having two or more vinyl, allyl, or other groups with 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, bonded to silicon atoms in one molecule. Component A1 is preferably a linear organopolysiloxane having one vinyl group at each end of the molecular chain, with side chains consisting of alkyl, phenyl, or other organic groups, or combinations thereof. The number of silicon atoms in one molecule (i.e., degree of polymerization) can be, for example, 1 to 1350, preferably around 150 to 300. It should be noted that this linear organopolysiloxane can also be an organopolysiloxane containing a small amount of branched structures (trifunctional siloxane units) in the molecule.

[0038] Based on the considerations of good workability and curing properties, the kinematic viscosity of the above-mentioned component A1 is preferably 10 to 10000 mm³. 2 / s, more preferably 50 to 550 mm 2 / s, further preferably 100–500 mm 2 / s. Kinematic viscosity is listed in the manufacturer's product catalog, etc., and is the kinematic viscosity at 25°C measured using an Uberloud viscometer.

[0039] Specific examples of component A1 mentioned above include dimethylvinylsiloxy-terminated dimethylpolysiloxane, methylphenylvinylsiloxy-terminated dimethylpolysiloxane, dimethylsiloxane-methylphenylsiloxane copolymer, and dimethylvinylsiloxy-terminated dimethylsiloxane-methylvinylsiloxane copolymer. These can be used alone or in combination of two or more.

[0040] [Ingredient A2]

[0041] The aforementioned component A2 is a fluorine-free organohydrogen polysiloxane having two Si-H groups per molecule. The molecular structure is preferably linear, with the Si-H groups preferably located at the two ends of the molecular chain. Organohydrogen polysiloxanes with a silicon atom count (i.e., degree of polymerization) of, for example, 2 to 1,000, preferably around 2 to 300, per molecule can be used. As organic groups bonded to silicon atoms other than hydrogen atoms, examples include non-substituted or substituted monovalent hydrocarbon groups that do not have aliphatic unsaturated bonds. For example, monovalent hydrocarbon groups with 1 to 10 carbon atoms, especially 1 to 6, are preferred. Specifically, examples include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, decyl, etc.; aryl groups such as phenyl, tolyl, xylyl, naphthyl, etc.; aralkyl groups such as benzyl, phenylethyl, phenylpropyl, etc.; and groups obtained by substituting part or all of the hydrogen atoms of these groups with halogen atoms other than fluorine such as bromine and chlorine, or cyano groups, such as chloromethyl, chloropropyl, bromoethyl, etc., halogen-substituted alkyl groups other than fluorine, cyanoethyl, etc.

[0042] Based on its good workability and curing properties, the kinematic viscosity of component A2 is preferably 2 to 10000 mm. 2 / s, more preferably 500–2000 mm 2 / s, further preferably 500–1500 mm 2 / s.

[0043] [Ingredient A3]

[0044] Component A3 is a fluorine-free organohydrogen polysiloxane having three or more Si-H groups in one molecule, and preferably an organohydrogen polysiloxane with a linear molecular structure. It should be noted that the organohydrogen polysiloxane may also be an organohydrogen polysiloxane containing a small amount of branched structure (trifunctional siloxane unit) in the molecular chain. As an example of such organohydrogen polysiloxane, an organohydrogen polysiloxane with the structure represented by the following general formula (1) can be shown.

[0045] [Chemical Formula 1]

[0046]

[0047] In the above formula, R 1 The hydrogen, alkyl, phenyl, epoxy, acryloyl, methacryloyl, and alkoxy groups are all the same or different from each other, and at least three of them are hydrogen. L is an integer from 0 to 1,000, especially from 0 to 300, and M is an integer from 1 to 200.

[0048] Based on the considerations of good workability and curing properties, the kinematic viscosity of the above-mentioned component A3 is preferably 20 to 10000 mm³. 2 / s, more preferably 60 to 8000 mm 2 / s, further preferably 60–200 mm 2 / s.

[0049] [Ingredient B]

[0050] Component B is a fluorinated organopolysiloxane having two or more alkenyl groups in one molecule. This fluorinated organopolysiloxane has two or more alkenyl groups, such as vinyl or allyl, with 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, bonded to silicon atoms in one molecule. Component B preferably has one vinyl group at each end of the molecular chain. Side chains may include unsubstituted or substituted monovalent hydrocarbon groups. Substituted monovalent hydrocarbon groups are linear fluorinated organopolysiloxanes consisting of alkyl, aryl, aralkyl, or other organic groups, or combinations thereof, in which some or all of the hydrogen atoms are replaced by fluorine atoms. As an example, a fluorinated dimethyl polysiloxane with at least two dimethylvinylsiloxy groups at its ends can be cited.

[0051] Based on the considerations of good workability and curing properties, the kinematic viscosity of component B is preferably 10–10000 mm³. 2 / s, more preferably 250–2000 mm 2 / s, further preferably 350–1500 mm 2 / s.

[0052] The substituents other than the alkenyl group in component B can be unsubstituted or substituted monovalent hydrocarbon groups that are the same as or different from each other and do not have aliphatic unsaturated bonds. The substituted monovalent hydrocarbon group is a monovalent hydrocarbon group obtained by substituting part or all of the hydrogen atoms with fluorine atoms. The unsubstituted or substituted monovalent hydrocarbon groups that do not have aliphatic unsaturated bonds are preferably monovalent hydrocarbon groups with 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms. Specifically, they are alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, decyl, etc., alkyl groups such as phenyl, tolyl, xylyl, naphthyl, etc., aryl groups such as benzyl, phenylethyl, phenylpropyl, etc., and substituents obtained by substituting part or all of the hydrogen atoms of these groups with fluorine atoms.

[0053] [Addition-curing catalyst]

[0054] Addition-curing catalysts are catalyst components that promote the curing of this composition. Catalysts used in hydrosilylation reactions can be used as addition-curing catalysts. Examples include platinum black, chloroplatinic (IV) acid, chloroplatinic acid hexahydrate, the reaction product of chloroplatinic acid hexahydrate and a monohydric alcohol, complexes of chloroplatinic acid hexahydrate with olefins or vinylsiloxanes, platinum group catalysts such as bis(acetylacetone)platinum, palladium group catalysts, and rhodium group catalysts.

[0055] Thermally conductive filler

[0056] The thermally conductive filler is preferably selected from at least one thermally conductive inorganic particle chosen from alumina, zinc oxide, silicon oxide, silicon carbide, aluminum nitride, boron nitride, aluminum hydroxide, and silicon dioxide. Alumina and aluminum nitride are particularly preferred. The shape of the thermally conductive filler is spherical, amorphous, needle-like, plate-like, etc., without particular limitation.

[0057] There are various types of alumina, including spherical alumina produced by heating and melting, sintered alumina produced by firing in a furnace, fused alumina produced by melting in an electric arc furnace, and high-purity alumina produced by hydrolysis of aluminum alkoxides or insitu chemical vapor deposition, etc., without particular limitation. The obtained alumina particles can also be set to a target particle size range by crushing or other methods.

[0058] Aluminum nitride is known to be produced by direct nitriding, reduction nitriding, combustion synthesis, etc., as well as agglomerated aluminum nitride obtained by further agglomerating the obtained aluminum nitride, and there are no particular limitations. The obtained aluminum nitride particles can also be set to the target particle size range by crushing, etc.

[0059] The average particle size of the thermally conductive filler is preferably 0.01 μm or more and 200 μm or less, more preferably 0.1 μm or more and 150 μm or less. It should be noted that the average particle size is the D50 (median particle size) of the cumulative particle size distribution based on volume in particle size distribution measurement using laser diffraction light scattering method. For example, the laser diffraction / scattering particle distribution measuring device LA-950S2 manufactured by Arihoba Corporation is used as the measuring instrument.

[0060] [Any ingredients]

[0061] The above-mentioned thermally conductive silicone composition may also contain, as needed, other components besides those listed above. Examples of components other than those listed above include heat-resistant enhancers such as titanium dioxide and cerium oxide, masterbatch compositions, curing delay agents, and flame-retardant additives. Organic or inorganic pigments may also be added for coloring and hue adjustment purposes, and silane coupling agents may also be added.

[0062] (Curing delay agent)

[0063] Ethynylcyclohexanol and other similar curing retardants are used. Preferably, the curing retardant is added at 0.001 to 0.1 parts by weight relative to 100 parts by weight of the base polymer.

[0064] (Masterbatch composition)

[0065] The masterbatch composition is preferably a mixture obtained by mixing 100 to 300 parts by weight of iron-containing powder with 100 parts by weight of uncrosslinked silicone gel. The masterbatch composition is preferably added in the form of 1 to 12 parts by weight, more preferably 1 to 10 parts by weight, relative to 100 parts by weight of the base polymer. The iron-containing powder is at least one selected from iron, iron oxide, and iron-containing metal oxides. Iron oxide is preferably at least one selected from magnetite (Fe3O4) and ferric oxide (Fe2O3). These are useful as colorants, stabilizers, flame retardants, etc.

[0066] The iron-containing powder is preferably surface-treated with a titanium-based or aluminum-based coupling agent. Surface treatment includes adsorption in addition to covalent bonding. It is believed that when the iron-containing powder is surface-treated with a coupling agent, the coupling agent molecules cover the surface of the iron-containing powder, thus preventing the adsorption of curing catalysts, such as platinum-based catalysts. Examples of surface treatment methods for the coupling agent include the dry method, wet method, and integral blending method described in Japanese Patent Application Publication No. 2020-7463. The aforementioned coupling agent is preferably added in an amount of 0.1 to 10 parts by weight relative to 100 parts by weight of the iron-containing powder, and more preferably 0.5 to 8 parts by weight.

[0067] (Silane coupling agent)

[0068] In thermally conductive silicone compositions, up to 0 to 200 parts by weight of a silane coupling agent may be added relative to 100 parts by weight of the base polymer. One example of a silane coupling agent is R(CH3). a Si(OR') 3-a (R is a non-substituted or substituted organogroup having 1 to 20 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, and a is 0 or 1) silane compounds, or their partial hydrolysates. Regarding R(CH3) a Si(OR') 3-aAlkoxysilane compounds (hereinafter referred to as "silanes") are shown as follows: (R is a non-substituted 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). Examples include methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, and octadecyltriethoxysilane. One or more of the above silane compounds may be used. Silane coupling agents can be used as surface treatment agents for thermally conductive inorganic particles.

[0069] The thermal conductivity of the above-mentioned thermally conductive organosilicon composition is preferably 0.8 W / mK or more, more preferably 1.0 W / mK or more, even more preferably 1.2 W / mK or more, even more preferably 2.0 W / mK or more, and even more preferably 2.3 W / mK or more.

[0070] The aforementioned thermally conductive silicone composition is preferably selected from at least one of gels and rubbers. Furthermore, the initial hardness of the aforementioned thermally conductive silicone composition, measured in ASKER C, is preferably in the range of 1 to 70, more preferably 20 to 60, and even more preferably 30 to 60. If it falls within the above range, it is soft and suitable as a thermally conductive material (TIM) sandwiched between a heat-generating element and a heat-dissipating element.

[0071] The weight change of the above-mentioned thermally conductive silicone composition after immersion in automotive oil (ATF) at 150°C for 24 hours is preferably 5% by weight or less, more preferably 0.1% by weight or more and 5% by weight or less. This results in good oil resistance. Samples for the oil resistance test can be molded articles with a width of 20 mm, a length of 20 mm, and a thickness of 3.0 mm.

[0072] The above-mentioned thermally conductive silicone composition is preferably formed into a sheet. If it is a sheet, it is suitable for being sandwiched between a heat-generating element and a heat-dissipating element.

[0073] The above-mentioned thermally conductive silicone composition is preferably a thermally conductive material sandwiched between a heating element and a heat sink. It is particularly suitable for applications exposed to organic solvents, petroleum, gasoline, etc.

[0074] A preferred method for manufacturing the thermally conductive sheet of the present invention is as follows: Components A1, A2, A3, B, an addition-curing catalyst, a thermally conductive filler, and any other required components are mixed at room temperature. Degassing under reduced pressure may be performed during or after mixing. The resulting thermally conductive silicone composition is then formed into a sheet by rolling or pressing. The resulting sheet is cured in an oven at 90–110°C for 10–30 minutes.

[0075] Example

[0076] The following examples illustrate the invention. The invention is not limited to these examples. Various parameters were measured using the methods described below.

[0077] Thermal conductivity

[0078] The thermal conductivity of the thermally conductive silicone composition was determined by Hot Disk (transient planar heat source method) (according to ISO / CD22007-2). The apparatus for measuring this thermal conductivity is as follows: Figure 1 As shown in Figure A, the polyimide film sensor 2 is clamped between two samples 3a and 3b. A constant power is applied to the sensor 2, causing it to heat up constantly, and the thermal characteristics are analyzed based on the temperature rise of the sensor 2. The front end 4 of the sensor 2 has a diameter of 7 mm, as shown in Figure A. Figure 1 As shown in B, the electrode has a double-helix structure, with an electrode 5 for applying current and an electrode 6 for measuring resistance (temperature measurement) arranged at the bottom. The thermal conductivity is calculated using the following formula (Mathematical Formula 1).

[0079] [Mathematical Expression 1]

[0080]

[0081] λ: Thermal conductivity (W / m·K)

[0082] P0: Constant power (W)

[0083] r: Radius of the sensor (m)

[0084]

[0085] α: Thermal diffusivity of the sample (m) 2 / s)

[0086] t: Measurement time (s)

[0087] D(τ): A dimensionless function of τ

[0088] ΔT(τ): Temperature rise of the sensor (K)

[0089] <Oil Resistance Evaluation Test>

[0090] (1) Prepare a silicone gel sheet with a length (L) of 20 mm, a width (W) of 20 mm, and a thickness (t) of 3.0 mm as a test piece.

[0091] (2) Determine the longitudinal and transverse dimensions, weight, and thickness of the test piece before it is immersed in ATF oil.

[0092] (3) Immerse the test piece in a test tube containing ATF oil.

[0093] (4) After plugging with cork, place in an oil bath and heat at 150°C for 24 hours.

[0094] (5) After cooling to room temperature, remove the test piece from the test tube and wipe off the remaining oil on the test piece with medicine wrapping paper.

[0095] (6) Measure the longitudinal (L), transverse (W) and thickness (t) dimensions after oil immersion.

[0096] (7) The weight change rate is calculated from the weight difference before and after the test using the following formula.

[0097] Weight change rate (wt%) = [(W2-W1) / W1]×100

[0098] Wherein, W1: weight of the test piece before the test (g), W2: weight of the test piece after the test (g)

[0099] <Hardness of thermally conductive silicone sheets>

[0100] The hardness of Asker C is determined using a rubber hardness tester specified in JIS K 7312.

[0101] (Examples 1-4, Comparative Examples 1-3)

[0102] 1. Raw material composition

[0103] (1) Basic polymer

[0104] A1: Has one vinyl group at each end of the molecular chain; kinematic viscosity is 350 mmHg. 2 / s of fluorine-free linear organopolysiloxanes (dimethylvinylsiloxy-terminated dimethylpolysiloxanes at both ends of the molecular chain)

[0105] A2: Contains two Si-H groups in one molecule, with a kinematic viscosity of 1040 mm⁻¹. 2 / s of fluorine-free linear organohydrogen polysiloxanes (dimethyl polysiloxanes with one Si-H group at each end of the molecular chain)

[0106] A3: Contains more than 3 Si-H groups in one molecule, with a kinematic viscosity of 100 mm.2 / s of fluorine-free linear organohydrogen polysiloxane (represented by the above general formula (1), L=32, M=26 linear organohydrogen polysiloxane, with 28 Si-H groups in 1 molecule)

[0107] B: It has one vinyl group at each end of the molecular chain and a kinematic viscosity of 1000 mm. 2 / s Fluorine-containing linear organopolysiloxane (fluorine-containing dimethyl polysiloxane with dimethyl vinyl siloxy groups at both ends of the molecular chain)

[0108] (2) Addition-curing catalysts

[0109] As an addition-curing catalyst, a commercially available platinum-based catalyst was used.

[0110] (3) Curing delay agent

[0111] Ethynylcyclohexanol was used as a curing delay agent.

[0112] (4) Coloring agents

[0113] The iron black masterbatch composition, obtained by adding 230 parts by weight of black iron oxide to 100 parts by weight of uncrosslinked silicone gel and mixing, was used as the colorant.

[0114] (5) Thermally conductive filler

[0115] (i) Spherical alumina, average particle size 75 μm, untreated.

[0116] (ii) Amorphous aluminum hydroxide, average particle size 50 μm, untreated.

[0117] (iii) Fragmented alumina, average particle size 2 μm, surface treatment agent: decyltrimethoxysilane

[0118] 2. Mixing

[0119] Add the above raw material components in the amounts shown in Tables 1 and 2 to a planetary mixer and mix at 23°C for 10 minutes. Degassing under reduced pressure is performed during or after mixing.

[0120] 3. Forming of cured sheets

[0121] The mixed thermally conductive composition was rolled to a thickness of 3 mm to form a sheet, which was then cured in an oven at 100°C for 10 minutes. The various physical properties of the resulting cured sheet are shown in Tables 1 and 2.

[0122] [Table 1]

[0123]

[0124] [Table 2]

[0125]

[0126] As shown in Tables 1 and 2, when the weight change rate of the oil resistance test results was observed, Examples 1-4 showed a smaller weight change rate compared to Comparative Examples 1-2, indicating excellent oil resistance. Comparative Example 3 had a high Asker C value, making it too hard to be used as a thermally conductive material (TIM). Regarding Examples 1-4, a balance between excellent oil resistance and suitable hardness for use as a thermally conductive material (TIM) was achieved.

[0127] Industrial availability

[0128] The thermally conductive silicone composition of the present invention is suitable for use as a thermally conductive material (TIM) sandwiched between a heat-generating part and a heat sink in electrical or electronic components in environments in contact with oil.

[0129] Explanation of symbols

[0130] 1. Thermal conductivity measuring device

[0131] 2 Sensors

[0132] Samples 3a and 3b

[0133] 4. Sensor front end

[0134] 5. Electrodes for applying current

[0135] 6. Electrodes for resistance measurement (electrodes for temperature measurement)

Claims

1. A thermally conductive organosilicon composition, which is a thermally conductive organosilicon composition with organopolysiloxane as the base polymer and containing a thermally conductive filler. The base polymer comprises non-fluorinated organopolysiloxanes and fluorinated organopolysiloxanes. The thermally conductive organosilicon composition is cured by an addition-curing catalyst. The ratio of the number of fluorine groups in the constituent components of the base polymer to the total number of alkenyl groups bonded to silicon atoms in the constituent components of the base polymer is 2.00 or more and 30.0 or less. The basic polymer comprises the following components: A1, A2, A3, and B. A1: A fluorine-free organopolysiloxane having two or more alkenyl groups in one molecule; A2: A fluorine-free organopolysiloxane having two Si-H groups in one molecule; A3: A fluorine-free organopolysiloxane having three or more Si-H groups in one molecule; B: Fluorinated organopolysiloxanes having two or more alkenyl groups in one molecule. Relative to a total of 100 parts by mass of component A1 and component B, it comprises: 50-100 parts by weight of the aforementioned component A2, 0.5 to 2 parts by weight of the aforementioned component A3, The catalytic amount of the addition-curing catalyst, and The thermally conductive filler comprises 100 to 4000 parts by mass relative to 100 parts by mass of the base polymer.

2. The thermally conductive organosilicon composition according to claim 1, wherein, The thermally conductive silicone composition is at least one selected from gels and rubbers.

3. The thermally conductive organosilicon composition according to claim 1 or 2, wherein, The initial hardness of the thermally conductive silicone composition is 1 to 70, calculated as Asker C.

4. The thermally conductive organosilicon composition according to claim 1 or 2, wherein, The thermally conductive silicone composition exhibits a weight change of less than 5% by weight after being impregnated in ATF at 150°C for 24 hours.

5. The thermally conductive organosilicon composition according to claim 1 or 2, wherein, The thermally conductive filler is at least one inorganic filler selected from alumina, aluminum hydroxide, boron nitride, aluminum nitride, silicon carbide, silicon nitride, and silicon dioxide.

6. The thermally conductive organosilicon composition according to claim 1 or 2, wherein, The thermally conductive silicone composition is formed into a sheet.

7. The thermally conductive organosilicon composition according to claim 1 or 2, wherein, The thermally conductive organosilicon composition is a thermally conductive material sandwiched between the heating element and the heat sink.

8. A method for manufacturing a thermally conductive silicone gel sheet, comprising: A composition containing a base polymer comprising both fluorine-free and fluorine-containing organopolysiloxanes, an addition-curing catalyst, and a thermally conductive filler is uniformly mixed, formed into a sheet, and then thermosetting. The ratio of the number of fluorine groups in the constituent components of the base polymer to the total number of alkenyl groups bonded to silicon atoms in the constituent components of the base polymer is 2.00 or more and 30.0 or less. The basic polymer comprises the following components: A1, A2, A3, and B. A1: A fluorine-free organopolysiloxane having two or more alkenyl groups in one molecule; A2: A fluorine-free organopolysiloxane having two Si-H groups in one molecule; A3: A fluorine-free organopolysiloxane having three or more Si-H groups in one molecule; B: Fluorinated organopolysiloxanes having two or more alkenyl groups in one molecule. Relative to a total of 100 parts by mass of component A1 and component B, it comprises: 50-100 parts by weight of the aforementioned component A2, 0.5 to 2 parts by weight of the aforementioned component A3, The catalytic amount of the addition-curing catalyst, and The thermally conductive filler comprises 100 to 4000 parts by mass relative to 100 parts by mass of the base polymer.

9. Use of the thermally conductive silicone composition according to any one of claims 1 to 6, wherein, The thermally conductive silicone composition is used as a thermally conductive material sandwiched between a heating element and a heat sink.

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