Heat-conducting silicone rubber composition, heat-conducting silicone rubber and preparation method thereof

Abstract

The invention provides a heat-conducting silicone rubber composition, heat-conducting silicone rubber and a preparation method thereof. The heat-conducting silicone rubber composition is prepared from the following components in percentage by mass: 1 to 30 percent of vinyl silicone oil, 65 to 97 percent of heat-conducting filler, 0.05 to 2 percent of cross-linking agent, 0.001 to 1.5 percent of catalyst, 0.25 to 1.5 percent of surface treating agent and 0.05 to 0.2 percent of end-capping reagent, wherein the mass ratio of the surface treating agent to the heat-conducting filler is (0.3-1): 100. The vinyl silicone oil is used as a basic polymer of the heat-conducting silicone rubber, has no hydrolytic activity, can realize in-situ treatment of the heat-conducting filler, and also can provide elasticity, high and low temperature resistance, weather resistance and other properties. In conclusion, the heat-conducting silicone rubber prepared from the heat-conducting silicone rubber composition has excellent storage stability, low viscosity, high heat conductivity coefficient and good cohesiveness, and the production cost is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicone rubber, in particular to a kind of heat-conducting silicone rubber composition, heat-conducting silicone rubber and preparation method thereof. BACKGROUND

[0002] Silicone rubber has the characteristics of high and low temperature resistance, cold and hot impact resistance and low modulus, and is suitable for electronic component sealing. Without other heat-conducting fillers, the thermal conductivity of silicone rubber itself is low, and heat generating parts such as LED and high-power motor will generate a large amount of heat, which will seriously affect the service life of the product if not dissipated in time. Therefore, it is urgent to develop a silicone rubber with high thermal conductivity and no corrosion.

[0003] One-component room temperature vulcanized silicone rubber (RTV) refers to a composition that forms a rubber-like elastomer by contacting with moisture in the air at room temperature. According to the different small molecules released, RTV is divided into deacid type, deoxime type, de-alcohol type and de-acetone type, etc. With the development of electronic and electrical industries, de-alcohol type RTV and de-acetone type RTV are widely used. The price of de-alcohol type RTV is relatively low, and it has less corrosion to the parts of electronic and electrical appliances, especially plastic parts. Therefore, the use amount and use range of de-alcohol type RTV are gradually expanding.

[0004] At present, the preparation method of de-alcohol type RTV with heat-conducting effect usually adopts a multi-step method, that is, the heat-conducting fillers are pretreated, the alkoxyl-terminated polydimethylsiloxane is prepared in advance, and finally the heat-conducting silicone rubber is prepared. However, this preparation method has the problems of complex process, poor compatibility of heat-conducting fillers, high viscosity, poor adhesion and high preparation cost. SUMMARY

[0005] The main purpose of the present application is to provide a kind of heat-conducting silicone rubber composition, heat-conducting silicone rubber and preparation method thereof, to solve the problems of poor compatibility of heat-conducting fillers in the prior art heat-conducting silicone rubber, high viscosity of heat-conducting silicone rubber, poor adhesion and high cost of raw materials.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a kind of heat-conducting silicone rubber composition is provided, which comprises, in mass percentage: 1-30% of vinyl silicone oil, 65-97% of heat-conducting filler, 0.05-2% of crosslinking agent, 0.001-1.5% of catalyst, 0.25-1.5% of surface treatment agent and 0.05-0.2% of end-capping agent;The mass ratio of surface treatment agent and heat-conducting filler is 0.3-1:100.

[0007] Further, the heat conductive silicone rubber composition comprises, in percentage by mass, 3-25% of the vinyl silicone oil, 75-95% of the heat conductive filler, 0.1-1% of the cross-linking agent, 0.005-0.8% of the catalyst, 0.3-0.95% of the surface treatment agent, and 0.05-0.15% of the end-capping agent.

[0008] Further, the vinyl silicone oil is selected from any one or more of a bivinyl-terminated polydimethylsiloxane, a monovinyl-terminated polydimethylsiloxane, a bivinyl-terminated and side-vinyl-terminated polydimethylsiloxane, a bivinyl-terminated and side-vinyl-terminated polydimethylsiloxane, a branched-vinyl-terminated polydimethylsiloxane; and / or, the mass content of the vinyl group in the vinyl silicone oil is 0.1-1.0%; and / or, the viscosity of the vinyl silicone oil is 50-1500 mPa·s; and / or, the end-capping agent is a siloxane compound containing a silicon-hydrogen group, the end-capping agent is selected from any one or more of trimethoxysilane, dimethoxymethylsilane, H(CH3)2SiOSi(CH3)2(OSi(CH3)2)m-CH2CH2-Si(OCH3)3, H(CH3)2SiOSi(CH3)2(OSi(CH3)2)m-CH2CH2-SiCH3(OCH3)2, wherein m is any integer from 0 to 5; and the molar ratio of the silicon-hydrogen group in the end-capping agent to the vinyl group in the vinyl silicone oil is 0.5-1:1.

[0009] Further, the surface treatment agent is selected from any one or more of a silicon-nitrogen-containing alkane, a trialkoxysilane, and a monovinyl-trimethoxysilane-terminated polydimethylsiloxane; wherein the silicon-nitrogen-containing alkane is selected from any one or more of hexamethyldisilazane, 1,3-divinyltetramethyldisilazane, 1,3-bis(trimethoxy)-tetramethyldisilazane, hexamethylcyclotrisilazane, and octamethylcyclotetrasilazane; the trialkoxysilane is selected from any one or more of propyltrimethoxysilane, octyltrimethoxysilane, octadecyltrimethoxysilane, dodecyltrimethoxysilane, and hexadecyltrimethoxysilane; and the monovinyl-trimethoxysilane-terminated polydimethylsiloxane has the chemical formula , n is 0-60; and / or, the heat conductive filler is selected from any one or more of a metal filler, a metal oxide, a nitride, a carbide, and a carbon substance; wherein the metal filler is selected from any one or more of gold, silver, copper, and aluminum; the metal oxide is selected from any one or more of aluminum oxide, zinc oxide, silicon dioxide, magnesium oxide, and titanium dioxide; the metal hydroxide is magnesium hydroxide and / or aluminum hydroxide; the nitride is selected from any one or more of boron nitride, aluminum nitride, boron nitride, and silicon nitride; the carbide is silicon carbide and / or boron carbide; and the carbon substance is selected from any one or more of diamond, graphite, fullerene, carbon nanotube, and graphene.

[0010] Further, the cross-linking agent is an alkoxysilane, the cross-linking agent is selected from any one or more of methyltrimethoxysilane, vinyltrimethoxysilane, propyltrimethoxysilane and butyltrimethoxysilane; and / or, the catalyst is an organotin catalyst and / or an organotitanium catalyst; wherein the organotin catalyst is selected from any one or more of dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dilaurate and alkoxysilane-modified tin catalyst; the organotitanium catalyst is selected from any one or more of isopropyl titanate, n-butyl titanate, t-butyl titanate, ethyl acetoacetate chelated isopropyl titanate and ethyl acetoacetate chelated n-butyl titanate; and / or, the heat-conducting silicone rubber composition further comprises a coupling agent, the mass content of the coupling agent is 0.01-0.5%; the coupling agent is any one or more of a reaction product of an alkoxysilane and an aminosilane, an aminosilane, an acrylosilane and an alkoxysilane; wherein the alkoxysilane is selected from any one or more of glycidyl ether propyltrimethoxysilane, glycidyl ether propyltriethoxysilane and glycidyl ether propylmethyldimethoxysilane; the aminosilane is selected from any one or more of amine propyltrimethoxysilane, amine propyltriethoxysilane, amine ethyl amine propyltrimethoxysilane, amine ethyl amine propyltriethoxysilane and an aminosilane oligomer; the acrylosilane is methacryloxytrimethoxysilane and / or methacryloxytriethoxysilane.

[0011] Further, the heat-conducting silicone rubber composition further comprises an auxiliary agent, the auxiliary agent is selected from any one or more of a plasticizer, a pigment and a thixotropy regulator; wherein the mass content of the plasticizer is 0.01-1%; the mass content of the pigment is 0.01-1%; the mass content of the thixotropy regulator is 0.01-1%.

[0012] According to another aspect of the present application, a heat-conducting silicone rubber is provided, which is prepared from the heat-conducting silicone rubber composition described above.

[0013] Further, the heat-conducting silicone rubber has a thermal conductivity of 1.5-4 W / m·K; the heat-conducting silicone rubber has a viscosity of 15-55 Pa·s; and the heat-conducting silicone rubber has a viscosity of 15-55 Pa·s after being stored for 180 days at 25℃.

[0014] According to still another aspect of the present application, there is provided a method for preparing the heat-conducting silicone rubber as described above, the method comprising: step S1, stirring a vinyl silicone oil in a vacuum environment to obtain a stirred vinyl silicone oil; step S2, adding a surface treatment agent to the stirred vinyl silicone oil in a nitrogen atmosphere, and performing a first mixing in a vacuum environment to obtain a first mixture; step S3, adding a heat-conducting filler to the first mixture in a nitrogen atmosphere, and performing a second mixing in a vacuum environment to obtain a second mixture; step S4, performing a temperature increase in a nitrogen atmosphere, and sequentially performing a third mixing in a nitrogen atmosphere, a fourth mixing in a vacuum environment on the second mixture to obtain a third mixture; step S5, performing a temperature decrease on the third mixture in a vacuum environment, and sequentially performing a fifth mixing in a nitrogen atmosphere, a sixth mixing in a vacuum environment on the third mixture after adding a capping agent to the third mixture in a nitrogen atmosphere to obtain a fourth mixture; and step S6, adding raw materials including a cross-linking agent and a catalyst to the fourth mixture in a nitrogen atmosphere, and performing a seventh mixing in a vacuum environment to obtain the heat-conducting silicone rubber.

[0015] Further, in the step S1, the temperature of the stirring is 20-25℃, and the time of the stirring is 5-10 min; and / or, in the step S2, the temperature of the first mixing is 20-25℃, and the time of the first mixing is 5-10 min; and / or, in the step S3, the temperature of the second mixing is 20-150℃, and the time of the second mixing is 5-10 min; and / or, in the step S4, the temperature of the third mixing and the fourth mixing is independently 130-150℃, and the time of the third mixing and the fourth mixing is independently 30-60 min; and / or, in the step S5, the time of the fifth mixing is 30-60 min, the time of the sixth mixing is 5-20 min, and the temperature of the fifth mixing and the sixth mixing is independently 30-60℃; and / or, in the step S6, the temperature of the seventh mixing is ≤50℃, and the time of the seventh mixing is 15-20 min; and / or, the raw materials further include a coupling agent and / or an auxiliary agent.

[0016] By applying the technical solution of this invention, the components and mass content of the thermally conductive silicone rubber composition are controlled within the above-mentioned range, resulting in relatively low raw material costs. The obtained single-component de-alcoholized silicone rubber exhibits good thermal conductivity and low viscosity, while also possessing excellent storage stability. It remains stable at room temperature for 180 days without any precipitation or stratification. Specifically, commonly used alkoxy silicone oils have high hydrolytic activity. Using them as base polymers, in-situ treatment of thermally conductive fillers is not possible, necessitating the use of surface-treated thermally conductive fillers, which increases costs and reduces stability. In contrast, the vinyl silicone oil of this application, as the base polymer for thermally conductive silicone rubber, has no hydrolytic activity, enabling in-situ treatment of thermally conductive fillers. It also provides properties such as elasticity, resistance to high and low temperatures, and weather resistance. Adding thermally conductive fillers improves the thermal conductivity of the silicone rubber. Further controlling the mass ratio of surface treatment agent to thermally conductive filler within the above-mentioned range improves the compatibility between the thermally conductive filler and the matrix, thereby reducing the overall viscosity of the thermally conductive silicone rubber. Simultaneously, it improves the dispersibility of the thermally conductive filler, thus enhancing the thermal conductivity of the silicone rubber. Crosslinking agents promote the formation of a three-dimensional network structure in polymers, leading to curing into a rubbery state. Catalysts accelerate the curing reaction, thereby shortening the curing time. End-capping agents are used for the end-capping reaction of vinyl silicone oil, enabling better preparation of dealcoholized condensation silicone rubber. In summary, the thermally conductive silicone rubber prepared from the thermally conductive silicone rubber composition of this application exhibits excellent storage stability, low viscosity, high thermal conductivity, and good adhesion, significantly reducing production costs. Detailed Implementation

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0018] As analyzed in the background section of this application, the prior art has problems such as poor compatibility of thermally conductive fillers in thermally conductive silicone rubber, high viscosity of thermally conductive silicone rubber, poor adhesion, and high raw material costs. In order to solve the above problems, this application provides a thermally conductive silicone rubber composition, thermally conductive silicone rubber, and a method for preparing the same.

[0019] In a typical embodiment of this application, a thermally conductive silicone rubber composition is provided, comprising, by weight percentage: 1-30% vinyl silicone oil, 65-97% thermally conductive filler, 0.05-2% crosslinking agent, 0.001-1.5% catalyst, 0.25-1.5% surface treatment agent, and 0.05-0.2% end-capping agent, wherein the mass ratio of surface treatment agent to thermally conductive filler is 0.3-1:100.

[0020] This application controls the composition and mass content of the thermally conductive silicone rubber composition within the aforementioned range, resulting in relatively low raw material costs. The obtained single-component, alcohol-free silicone rubber exhibits good thermal conductivity and low viscosity, along with excellent storage stability. It remains stable in viscosity after 180 days of storage at room temperature, showing no precipitation or stratification. Specifically, commonly used alkoxy silicone oils have high hydrolytic activity, making in-situ treatment of thermally conductive fillers impossible when using them as base polymers. Surface-treated thermally conductive fillers must be used, leading to increased costs and poor stability. In contrast, the vinyl silicone oil used in this application, as the base polymer for thermally conductive silicone rubber, is non-hydrolytic, enabling in-situ treatment of thermally conductive fillers while also providing properties such as elasticity, high and low temperature resistance, and weather resistance. Adding thermally conductive fillers improves the thermal conductivity of the silicone rubber. Further controlling the mass ratio of surface treatment agent to thermally conductive filler within the aforementioned range enhances the compatibility between the thermally conductive filler and the matrix, thereby reducing the overall viscosity of the thermally conductive silicone rubber. Simultaneously, it improves the dispersibility of the thermally conductive filler, further enhancing its thermal conductivity. Crosslinking agents promote the formation of a three-dimensional network structure in polymers, leading to curing into a rubbery state. Catalysts accelerate the curing reaction, thereby shortening the curing time. End-capping agents are used for the end-capping reaction of vinyl silicone oil, enabling better preparation of dealcoholized condensation silicone rubber. In summary, the thermally conductive silicone rubber prepared from the thermally conductive silicone rubber composition of this application exhibits excellent storage stability, low viscosity, high thermal conductivity, and good adhesion, significantly reducing production costs.

[0021] Furthermore, the mass content of vinyl silicone oil can be 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 27%, or 30%, or any value within that range. The mass content of thermally conductive filler can be 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 97%, or any value within that range. The mass content of crosslinking agent can be 0.05%, 0.1%, 0.3%, 0.5%, 0.7%, 1.0%, 1.2%, 1.5%, 1.7%, or 2%, or any value within that range. The mass content of catalyst can be 0.001%, 0.1%, 0.3%, 0.5%, 0.7%, 1.0%, 1.2%, or 1.5%, or any value within that range. The mass content of surface treatment agent can be 0.25%, 0.3%, 0.4%, 0.5%, 0.6%, 0.8%, 1.0%, 1.2%, or 1.5%, or any value within that range. The mass content of the end-capping agent can be 0.05%, 0.1%, 0.12%, 0.15%, 0.17%, or 0.2%, or any value within that range. The mass ratio of the surface treatment agent to the thermally conductive filler can be 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100, or 1:100, or any value within that range.

[0022] To further improve the overall performance of the thermally conductive silicone rubber composition, in one embodiment of this application, the thermally conductive silicone rubber composition comprises, by weight percentage: 3-25% vinyl silicone oil, 75-95% thermally conductive filler, 0.1-1% crosslinking agent, 0.005-0.8% catalyst, 0.3-0.95% surface treatment agent, and 0.05-0.15% end-capping agent.

[0023] In one embodiment of this application, the vinyl silicone oil is selected from any one or more of the following: double-vinyl-terminated polydimethylsiloxane, single-vinyl-terminated polydimethylsiloxane, double-vinyl-terminated and side-chain vinyl-terminated polydimethylsiloxane, double-methyl-terminated and side-chain vinyl-terminated polydimethylsiloxane, and branched vinyl-terminated polydimethylsiloxane, preferably double-vinyl-terminated polydimethylsiloxane and / or single-vinyl-terminated polydimethylsiloxane; and / or, the vinyl content in the vinyl silicone oil is 0.1~1.0% by mass; and / or, the viscosity of the vinyl silicone oil is 50~1500 mPa·s, preferably 100~1500 mPa·s. Pa·s, more preferably 350~1200 mPa·s; and / or, the capping agent is a siloxane compound containing silane groups, the capping agent being selected from any one or more of trimethoxysilane, dimethoxymethylsilane, H(CH3)2SiOSi(CH3)2(OSi(CH3)2)m-CH2CH2-Si(OCH3)3, H(CH3)2SiOSi(CH3)2(OSi(CH3)2)m-CH2CH2-SiCH3(OCH3)2; wherein, m is any integer from 0 to 5; the molar ratio of the silane groups in the capping agent to the vinyl groups in the vinyl silicone oil is 0.5~1:1.

[0024] Preferably controlling the type of vinyl silicone oil within the above-mentioned range not only helps promote the crosslinking reaction, thereby optimizing the curing speed and adjusting the mechanical properties of the thermally conductive silicone rubber, but also helps improve its compatibility with thermally conductive fillers, thereby improving the thermal conductivity and overall stability of the thermally conductive silicone rubber. Preferably, the vinyl content in the vinyl silicone oil being within the above-mentioned range helps control the viscosity of the vinyl silicone oil within the above-mentioned range, thereby adjusting the rheological properties of the thermally conductive silicone rubber composition, and further improving the storage stability of the thermally conductive silicone rubber.

[0025] Preferring a type of end-capping agent within the above-mentioned range helps to adjust the hardness and elasticity of the thermally conductive silicone rubber after curing. Preferably controlling the molar ratio of silanol groups in the end-capping agent to vinyl groups in the vinyl silicone oil within the above-mentioned range helps to more precisely adjust the hardness and elasticity of the thermally conductive silicone rubber after curing, ensuring that the thermally conductive silicone rubber maintains good physical properties and compatibility even with high thermal conductivity filler filling.

[0026] In one embodiment of this application, the surface treatment agent is selected from any one or more of silazane, trialkoxysilane, and polydimethylsiloxanes capped with a single-terminal trimethoxysilane; wherein, the silazane is selected from any one or more of hexamethyldisilazane, 1,3-divinyltetramethyldisilazane, 1,3-di(trimethoxy)-tetramethyldisilazane, hexamethylcyclotrisilazane, and octamethylcyclotetrasilazane, preferably 1,3-divinyltetramethyldisilazane and / or 1,3-di(trimethoxy)-tetramethyldisilazane; the trialkoxysilane is selected from any one or more of propyltrimethoxysilane, octyltrimethoxysilane, decanyltrimethoxysilane, dodecyltrimethoxysilane, and hexadecyltrimethoxysilane, preferably dodecyltrimethoxysilane and / or hexadecyltrimethoxysilane; the chemical formula of the polydimethylsiloxane capped with a single-terminal trimethoxysilane is […]. n is 0~60, preferably 20~50; and / or, the thermally conductive filler is selected from any one or more of metal fillers, metal oxides, nitrides, carbides and carbonaceous materials; wherein, the metal filler is selected from any one or more of gold, silver, copper and aluminum; the metal oxide is selected from any one or more of aluminum oxide, zinc oxide, silicon dioxide, magnesium oxide and titanium dioxide; the metal hydroxide is magnesium hydroxide and / or aluminum hydroxide; the nitride is selected from any one or more of boron nitride, aluminum nitride, boron nitride and silicon nitride; the carbide is silicon carbide and / or boron carbide; the carbonaceous material is selected from any one or more of diamond, graphite, fullerene, carbon nanotubes and graphene.

[0027] Preferential surface treatment agents within the aforementioned range help improve the interfacial compatibility between the thermally conductive filler and the matrix, as well as the dispersibility of the thermally conductive filler, thereby reducing the viscosity of the thermally conductive silicone rubber and enhancing its mechanical and thermal conductivity properties. Among these, silazanes, through their unique chemical properties, form stable chemical bonds, which helps enhance the compatibility between the thermally conductive filler and the organic phase, thus optimizing the heat conduction path of the thermally conductive silicone rubber. Trialkoxysilanes, with their longer alkyl chains, help increase the flowability of the thermally conductive silicone rubber, maintaining good processing performance even at high filler contents. Polydimethylsiloxanes with single-terminated trimethoxysilanes possessing the above-mentioned structure help form a hydrophobic protective layer on the surface of the thermally conductive filler, reducing the consumption of crosslinking agents caused by moisture intrusion, thereby improving the storage stability and curing performance of the thermally conductive silicone rubber.

[0028] Choosing the right thermally conductive filler within the aforementioned range helps improve the thermal conductivity of thermally conductive silicone rubber. Furthermore, appropriate thermally conductive fillers can be selected based on different application scenarios. For example, metal fillers also help improve electrical conductivity. Metal oxides provide good thermal conductivity while maintaining good insulation. Nitrides not only help improve the thermal conductivity of thermally conductive silicone rubber but also help improve its mechanical properties and thermal stability. Carbonaceous materials help to balance the dual requirements of lightweight and high thermal conductivity.

[0029] The median particle size of the preferred metal filler, metal oxide, and nitride is 0.1~150 μm.

[0030] The preferred thermally conductive filler is a combination of first spherical alumina with a median particle size of 0.5~1.5μm, second spherical alumina with a median particle size of 5~15μm, and third spherical alumina with a median particle size of 45~100μm. The mass ratio of the first spherical alumina, the second spherical alumina, and the third spherical alumina is 2~15:15~35:50~80, which helps to form a particle size gradient in the thermally conductive filler, thereby further improving the dispersibility and stability of the thermally conductive filler, and thus enabling the thermally conductive silicone rubber to maintain a low viscosity and improve its mechanical properties.

[0031] The preferred thermally conductive filler is a combination of first spherical alumina, second spherical alumina, third spherical alumina, and metallic aluminum, with a mass ratio of 2~15:5~20:50~80:5~20. This combination facilitates tight packing of the thermally conductive filler, and the higher thermal conductivity of metallic aluminum prevents the formation of conductive pathways that would compromise insulation. Therefore, with the same amount added, the thermally conductive silicone rubber exhibits a higher thermal conductivity. Alternatively, the preferred thermally conductive filler is a combination of first spherical alumina, second spherical alumina, third spherical alumina, and aluminum nitride, with a mass ratio of 2~15:5~20:50~80:5~20. This combination facilitates tight packing of the thermally conductive filler, and the higher thermal conductivity of aluminum nitride compared to alumina results in a higher thermal conductivity of the thermally conductive silicone rubber with the same amount added.

[0032] In one embodiment of this application, the crosslinking agent is an alkoxysilane, selected from any one or more of methyltrimethoxysilane, vinyltrimethoxysilane, propyltrimethoxysilane, and butyltrimethoxysilane, preferably methyltrimethoxysilane and / or vinyltrimethoxysilane; and / or, the catalyst is an organotin catalyst and / or an organotitanium catalyst; wherein, the organotin catalyst is selected from any one or more of dibutyltin dilaurate, dibutyltin diacetate, tin dilaurate-decanate, and alkoxysilane-modified tin catalyst, preferably an alkoxysilane-modified tin catalyst; the organotitanium catalyst is selected from any one or more of isopropyl titanate, n-butyl titanate, ethyl acetoacetate chelated titanate, and ethyl acetoacetate chelated titanate, preferably ethyl acetoacetate chelated titanate and / or ethyl acetoacetate chelated titanate; and / or Alternatively, the thermally conductive silicone rubber composition may further include a coupling agent, the mass content of which is 0.01~0.5%; the coupling agent is any one or more of the reaction product of alkoxysilane and aminosilane, aminosilane, acrylate silane, and alkoxysilane; wherein, the alkoxysilane is selected from any one or more of glycidyl ether propyltrimethoxysilane, glycidyl ether propyltriethoxysilane, and glycidyl ether propylmethyldimethoxysilane, preferably glycidyl ether propyltrimethoxysilane; the aminosilane is selected from any one or more of aminopropyltrimethoxysilane, aminopropyltriethoxysilane, aminoethylaminopropyltrimethoxysilane, aminoethylaminopropyltriethoxysilane, and aminosilane oligomers, preferably aminopropyltrimethoxysilane and / or aminopropyltriethoxysilane; the acrylate silane is methacryloxytrimethoxysilane and / or methacryloxytriethoxysilane.

[0033] The preferred crosslinking agent, falling within the aforementioned range, helps promote its reaction with vinyl silicone oil to form a three-dimensional network structure. The preferred catalyst, also falling within the aforementioned range, helps promote the crosslinking reaction, shortens curing time, and thus improves curing efficiency. Adding coupling agents of the aforementioned types and mass percentages helps enhance the interfacial bonding between the thermally conductive filler and the silicone rubber matrix, thereby improving the thermal conductivity and mechanical properties of the thermally conductive silicone rubber, while also helping to improve the dispersibility and compatibility of the thermally conductive filler.

[0034] Preparation method of reaction product of alkoxysilane and aminosilane: glycidyl ether propyltrimethoxysilane and aminopropyltrimethoxysilane are mixed in a molar ratio of 1~2:1 and placed at room temperature (20~25℃) for 7~14 days.

[0035] In one embodiment of this application, the thermally conductive silicone rubber composition further includes additives selected from any one or more of plasticizers, pigments, and thixotropic modifiers; wherein the mass content of the plasticizer is 0.01~1%; the mass content of the pigment is 0.01~1%; and the mass content of the thixotropic modifier is 0.01~1%.

[0036] Additives help optimize the overall properties of the thermally conductive silicone rubber composition. Preferably, the plasticizer is a non-reactive silicone oil and / or an alkane solvent. The non-reactive silicone oil is polydimethylsiloxane (PDMS), and the alkane solvent is selected from one or more of mineral oil, cyclopentane, and paraffin oil. The type and mass content of the plasticizer preferably fall within the above-mentioned range, which helps reduce the viscosity of the thermally conductive silicone rubber, improve its flexibility, and enhance its processing performance. Pigments include, but are not limited to, carbon black, titanium dioxide, and phthalocyanine blue pigments. The addition of pigments helps provide color to the silicone rubber, facilitating identification. Thixotropic modifiers are selected from one or more of organobentonite, polyamide wax, and cellulose derivatives. The type and mass content of the thixotropic modifier preferably fall within the above-mentioned range, which helps regulate the rheological properties of the thermally conductive silicone rubber composition, reducing sedimentation and stratification during storage, thereby maintaining good storage stability.

[0037] In another typical embodiment of this application, a thermally conductive silicone rubber is provided, which is prepared from a thermally conductive silicone rubber composition comprising the above-mentioned thermally conductive silicone rubber composition.

[0038] The thermally conductive silicone rubber prepared from the above-mentioned thermally conductive silicone rubber composition of this application has excellent storage stability, low viscosity, high thermal conductivity and good adhesion, and non-surface-treated thermally conductive fillers can be selected to reduce costs.

[0039] In one embodiment of this application, the thermal conductivity of the thermally conductive silicone rubber is 1.5~4 W / m·K; the viscosity of the thermally conductive silicone rubber is 15~55 Pa·s; and after being stored at 25°C for 180 days, the viscosity of the thermally conductive silicone rubber is 15~55 Pa·s.

[0040] The thermally conductive silicone rubber of this application has good thermal conductivity, and its thermal conductivity coefficient can reach the above-mentioned range. The thermally conductive silicone rubber also has low viscosity and good storage stability, and its viscosity and post-storage viscosity can reach the above-mentioned range.

[0041] In another typical embodiment of this application, a method for preparing the above-mentioned thermally conductive silicone rubber is provided. The method includes: step S1, stirring vinyl silicone oil under vacuum to obtain stirred vinyl silicone oil; step S2, adding a surface treatment agent to the stirred vinyl silicone oil under a nitrogen atmosphere and performing a first mixing under vacuum to obtain a first mixture; step S3, adding a thermally conductive filler to the first mixture under a nitrogen atmosphere and performing a second mixing under vacuum to obtain a second mixture; step S4, heating under a nitrogen atmosphere and performing a third mixing under a nitrogen atmosphere and a fourth mixing under vacuum to obtain a third mixture; step S5, cooling the third mixture under vacuum and adding a capping agent to the third mixture under a nitrogen atmosphere and performing a fifth mixing under a nitrogen atmosphere and a sixth mixing under vacuum to obtain a fourth mixture; and step S6, adding raw materials including a crosslinking agent and a catalyst to the fourth mixture under a nitrogen atmosphere and performing a seventh mixing under vacuum to obtain thermally conductive silicone rubber.

[0042] This application provides a one-pot method for preparing a single-component dealcoholized thermally conductive silicone rubber, which involves online treatment of the thermally conductive filler and simultaneous preparation of alkoxy-terminated polydimethylsiloxane. First, in step S1, vinyl silicone oil is stirred under vacuum. This pretreatment step removes air, thereby improving the efficiency of subsequent reactions and the purity of the product. Then, in step S2, a surface treatment agent is added under a nitrogen atmosphere and mixed with the vinyl silicone oil under vacuum. This not only promotes the uniform dispersion of the surface treatment agent but also enhances the reactivity under vacuum, facilitating subsequent surface treatment of the thermally conductive filler. This improves the compatibility between the thermally conductive filler and the silicone rubber matrix and reduces the viscosity of the thermally conductive silicone rubber. Steps S3 and S4 allow for thorough surface treatment of the thermally conductive filler, further improving the compatibility between the inorganic and organic phases. In step S5, the addition of a capping agent allows for more precise control of the curing behavior of the thermally conductive silicone rubber, effectively controlling the hardness and softness of the cured rubber. Finally, the above-mentioned raw materials are added in step S6 to ensure thorough mixing and reaction of the components, resulting in a single-component, alcohol-free, thermally conductive silicone rubber. The preparation method of this application is simple, the thermally conductive filler treatment is self-controlled, it exhibits better adhesion to the substrate, and non-surface-treated thermally conductive fillers can be selected to reduce costs. Furthermore, online treatment of the thermally conductive filler allows for more complete surface treatment, thereby improving the compatibility between the inorganic and organic phases. The resulting thermally conductive silicone rubber has lower viscosity and higher thermal conductivity.

[0043] Nitrogen vacuum breaking is a safe and effective method to prevent impurities in the air from affecting the vacuum system. It also avoids hydrolysis caused by moisture in the air, which could affect stability, thus protecting the cleanliness and stability of the reaction. Achieving the aforementioned nitrogen atmosphere is preferably done through nitrogen vacuum breaking.

[0044] In one embodiment of this application, in step S1, the stirring temperature is 20-25°C and the stirring time is 5-10 min; and / or, in step S2, the first mixing temperature is 20-25°C and the first mixing time is 5-10 min; and / or, in step S3, the second mixing temperature is 20-150°C and the second mixing time is 5-10 min; and / or, in step S4, the third and fourth mixing temperatures are each independently 130°C-150°C and the third and fourth mixing times are each independently 30-60 min; and / or, in step S5, the fifth mixing time is 30-60 min and the sixth mixing time is 5-20 min, and the fifth and sixth mixing temperatures are each independently 30-60°C; and / or, in step S6, the seventh mixing temperature is ≤50°C and the seventh mixing time is 15-20 min; and / or, the raw materials also include coupling agents and / or additives.

[0045] In step S1, it is preferable to control the stirring temperature and time within the above range, which helps to uniformly disperse the vinyl silicone oil, reduce changes in material properties caused by high temperature, and thus facilitate the stable progress of subsequent reactions.

[0046] In step S2, it is preferable to control the temperature and time of the first mixing within the above range, which helps the surface treatment agent to be evenly dispersed, thereby facilitating the subsequent surface treatment of the thermally conductive filler.

[0047] In step S3, it is preferable to control the temperature and time of the second mixing within the above range, which helps the thermally conductive filler to be fully dispersed in the matrix, thereby facilitating surface treatment.

[0048] In step S4, after the nitrogen gas is purged from the vacuum, the temperature is raised to 130~150℃. At this temperature, the third and fourth mixing processes are carried out. Controlling the third and fourth mixing processes within the above range helps to promote the modification of the thermally conductive filler by the surface treatment agent, thereby improving the compatibility between the thermally conductive filler and the silicone rubber matrix, reducing the viscosity of the thermally conductive silicone rubber, and thus improving the thermal conductivity of the thermally conductive silicone rubber.

[0049] In step S5, the vacuum environment is cooled to 30~60℃ and nitrogen is used to break the vacuum. The end-capping agent is added, and the atmosphere, temperature and time of the fifth and sixth mixtures are controlled within the above range. This helps to promote the full reaction of the end-capping agent with the vinyl silicone oil, forming a stable de-alcoholized structure. It also helps to adjust the hardness and softness of the thermally conductive silicone rubber after curing.

[0050] In step S6, the crosslinking agent, catalyst, coupling agent and additives are added and the temperature and time of the seventh mixing are controlled within the above range. This helps to promote the uniform distribution of the above components in the matrix, reduces the occurrence of side reactions, and thus improves the performance stability of the final product, thermally conductive silicone rubber.

[0051] The beneficial effects of this application will be further illustrated below with reference to the embodiments.

[0052] raw material:

[0053] Double-ended vinyl polydimethylsiloxane: vinyl content is 0.43% by mass, viscosity is 500 mPa·s, Zhejiang Runhe Organosilicon New Material Co., Ltd., RH-Vi311.

[0054] Single-ended vinyl polydimethylsiloxane: single-ended ratio 80%, vinyl content 0.23% by mass, viscosity 1000 mPa·s, Zhejiang Runhe Organosilicon New Material Co., Ltd., RH-Vi305B.

[0055] Bis-terminated trimethoxy-terminated polydimethylsiloxane: viscosity is 500 mPa·s.

[0056] Surface treatment agent 1,3-bis(trimethoxy)-tetramethyldisilazane.

[0057] Surface treatment agent: single-terminated trimethoxysilane-terminated polydimethylsiloxane; chemical formula: n is 0~60, and the viscosity is 15 mPa·s.

[0058] All thermally conductive fillers are untreated.

[0059] End-capping agent trimethoxysilane: Bailingwei, with a hydrogen content of 0.82% by mass.

[0060] Crosslinking agent methyltrimethoxysilane: MTMO from Hangzhou Sibao Chemical Co., Ltd.

[0061] Catalyst ethyl acetoacetate chelates titanate n-butyl: Dorf Ketal Chemicals, Tyzor KE-6.

[0062] The reaction product of the coupling agent glycidyl ether propyltrimethoxysilane and aminopropyltrimethoxysilane is prepared by mixing glycidyl ether propyltrimethoxysilane (Evonik Industries AG, GLYMO) and aminopropyltrimethoxysilane (Evonik Industries AG, AMMO) at a molar ratio of 1:1 and placing them at room temperature (25°C) for 7 days.

[0063] Example 1

[0064] Step S1: Add vinyl silicone oil to a planetary mixer, evacuate the vacuum to -0.09 MPa, and stir at 25°C for 5 minutes under vacuum to obtain stirred vinyl silicone oil.

[0065] Step S2: After breaking the vacuum with nitrogen, the surface treatment agent is added to the stirred vinyl silicone oil under a nitrogen atmosphere. After evacuation, the vacuum degree is -0.09MPa. The first mixing is carried out at 25°C for 7 minutes under vacuum to obtain the first mixture.

[0066] Step S3: After breaking the vacuum with nitrogen, thermally conductive spherical alumina with a median particle size of 0.5 μm, 5 μm, and 45 μm are sequentially added to the first mixture under a nitrogen atmosphere. After evacuation, the vacuum degree is -0.09 MPa. The mixture is then mixed for 15 min at 100°C under vacuum to obtain the second mixture.

[0067] Step S4: After breaking the vacuum with nitrogen, the temperature is raised to 140°C. The second mixture is mixed for 40 minutes in a nitrogen atmosphere. The vacuum is then continued to be drawn to a vacuum degree of -0.09 MPa. The mixture is then mixed for 30 minutes in a vacuum environment to obtain the third mixture.

[0068] Step S5: Vacuuming. When the temperature drops to 60°C in the vacuum environment, nitrogen is used to break the vacuum. The end-capping agent is added to the third mixture and the fifth mixture is carried out in a nitrogen atmosphere for 40 minutes. Vacuuming continues until the vacuum degree is -0.09MPa. The sixth mixture is carried out in a vacuum environment for 10 minutes to obtain the fourth mixture. Throughout the process, the temperature inside the thermostat is controlled at 30°C to 60°C.

[0069] Step S6: After breaking the vacuum with nitrogen, the crosslinking agent, catalyst and coupling agent are added to the fourth mixture under a nitrogen atmosphere. The temperature inside the reactor is controlled to not exceed 50°C. A vacuum is drawn with a vacuum degree of -0.09MPa. The seventh mixing is carried out in a vacuum environment for 15 minutes. After breaking the vacuum with nitrogen, thermally conductive silicone rubber is obtained.

[0070] The specific types and weight proportions of the above raw materials are shown in Table 1.

[0071] Examples 2 to 8

[0072] The difference from Example 1 is that the composition and weight of the raw materials are different, as shown in Tables 1 and 2.

[0073] Example 9

[0074] The difference from Example 1 is that the surface modifier has a mass content of 0.91%, the total mass content of the thermally conductive filler is 90.64%, and the mass ratio of the surface modifier to the thermally conductive filler is 1:100, resulting in thermally conductive silicone rubber.

[0075] Example 10

[0076] The difference from Example 1 is that the vinyl silicone oil is a polydimethylsiloxane with double vinyl end caps, the vinyl content is 0.28% by mass, the viscosity is 1500 mPa·s, and the final product is a thermally conductive silicone rubber.

[0077] Example 11

[0078] The difference from Example 1 is that the vinyl silicone oil is a polydimethylsiloxane with double vinyl end caps, the vinyl content is 0.23% by mass, the viscosity is 2000 mPa·s, and the final product is thermally conductive silicone rubber.

[0079] Example 12

[0080] The difference from Example 1 is that in step S4, after breaking the vacuum with nitrogen, the temperature is raised to 150°C, the second mixture is mixed for a third time in a nitrogen atmosphere for 60 minutes, and then the vacuum is continued to be drawn to a vacuum degree of -0.09MPa. The mixture is then mixed for a fourth time in a vacuum environment for 30 minutes to obtain the third mixture, and finally the thermally conductive silicone rubber is obtained.

[0081] Example 13

[0082] The difference from Example 1 is that in step S4, after breaking the vacuum with nitrogen, the temperature is raised to 100°C, the second mixture is mixed for a third time in a nitrogen atmosphere for 90 minutes, and then the vacuum is continued to be drawn to a vacuum degree of -0.09MPa. The mixture is then mixed for a fourth time in a vacuum environment for 20 minutes to obtain the third mixture, and finally the thermally conductive silicone rubber is obtained.

[0083] Example 14

[0084] The difference from Example 1 is that in step S1, vinyl silicone oil is added to a planetary stirring vessel, and after evacuation, the vacuum degree is -0.09MPa. The mixture is stirred at 20°C for 10 minutes under vacuum to obtain stirred vinyl silicone oil.

[0085] Step S2: After breaking the vacuum with nitrogen, the surface treatment agent is added to the stirred vinyl silicone oil. After evacuation, the vacuum degree is -0.09MPa. The first mixing is carried out at 20°C for 5 minutes under vacuum to obtain the first mixture.

[0086] Step S3: After nitrogen venting, thermally conductive spherical alumina with a median particle size of 0.5 μm, 5 μm, and 45 μm are sequentially added to the first mixture. After evacuation, the vacuum degree is -0.09 MPa. The mixture is then mixed for 10 min at 20°C under vacuum to obtain the second mixture.

[0087] Step S4: After breaking the vacuum with nitrogen, the temperature is raised to 130°C. The second mixture is mixed for a third time in a nitrogen atmosphere for 30 minutes. The vacuum is then continued to be drawn, with a vacuum degree of -0.09 MPa. The mixture is then mixed for a fourth time in a vacuum environment for 60 minutes to obtain the third mixture.

[0088] Step S5: Vacuuming. When the temperature drops by 30°C in the vacuum environment, nitrogen is used to break the vacuum. The end-capping agent is added to the third mixture and the fifth mixture is carried out in a nitrogen atmosphere for 30 minutes. Vacuuming continues until the vacuum degree is -0.09MPa. The sixth mixture is carried out in a vacuum environment for 20 minutes to obtain the fourth mixture. Throughout the process, the temperature inside the thermostat is controlled at 30°C to 60°C.

[0089] Step S6: After breaking the vacuum with nitrogen, the crosslinking agent, catalyst and coupling agent are added to the fourth mixture. The temperature inside the reactor is controlled to not exceed 50°C. Vacuum is drawn with a vacuum degree of -0.09MPa. The seventh mixing is carried out in a vacuum environment for 20 minutes. After breaking the vacuum with nitrogen, thermally conductive silicone rubber is obtained.

[0090] Comparative Examples 1 to 4

[0091] The difference from Example 1 is that the composition and weight of the raw materials are different, as shown in Table 3.

[0092] Test method:

[0093] Viscosity (including storage viscosity): The viscosity at 25°C shall be determined using a rotational viscometer in accordance with GB / T2794.

[0094] Surface drying: Test its surface drying time according to GB / T-13477, test conditions: 23℃ / 50%RH.

[0095] Hardness after curing: The hardness after curing was tested according to GB / T-531. Curing conditions: 23℃ / 50%RH, curing for 7 days.

[0096] Thermal conductivity: Curing conditions: 23℃ / 50%RH, curing for 7 days. Measured according to ISO 22007-2.

[0097] Separation after storage: Place the uncured sample into a 310mL polypropylene rigid tube and seal it. After standing vertically at room temperature (25℃) for 180 days, test the viscosity; observe whether liquid precipitates from the upper layer to determine the separation performance.

[0098] The test results are shown in Table 4.

[0099] Table 1

[0100]

[0101] Table 2

[0102]

[0103] Table 3

[0104]

[0105] Table 4

[0106]

[0107] In Comparative Example 2, the viscosity of the thermally conductive silicone rubber was too high, exceeding the range of the viscometer, and a specific value could not be measured. In Comparative Example 3, the rubber could not be prepared and almost solidified inside the planetary reactor.

[0108] In Table 4, "no stratification," "slight oil separation at the head," "severe stratification," and "curing in the tube" indicate that the uncured thermally conductive silicone rubber gradually developed severe stratification after 180 days of storage. Among them, "slight oil separation at the head" has a relatively small impact on viscosity and is basically equivalent to the situation indicated by "no stratification."

[0109] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0110] This application controls the composition and mass content of the thermally conductive silicone rubber composition within the aforementioned range, resulting in relatively low raw material costs. The obtained single-component, alcohol-free silicone rubber exhibits good thermal conductivity and low viscosity, along with excellent storage stability. It shows no precipitation or stratification after 180 days of storage at room temperature, and its viscosity remains stable. Specifically, commonly used alkoxy silicone oils have high hydrolytic activity. Using them as base polymers, in-situ treatment of thermally conductive fillers is not possible, necessitating the use of surface-treated fillers, which increases costs and reduces stability. In contrast, the vinyl silicone oil used in this application, as the base polymer for thermally conductive silicone rubber, is non-hydrolytic, enabling in-situ treatment of thermally conductive fillers while also providing properties such as elasticity, high and low temperature resistance, and weather resistance. Adding thermally conductive fillers improves the thermal conductivity of the silicone rubber. Further controlling the mass ratio of surface treatment agent to thermally conductive filler within the aforementioned range improves the compatibility between the filler and the matrix, thereby reducing the overall viscosity of the thermally conductive silicone rubber. Simultaneously, it improves the dispersibility of the filler, further enhancing its thermal conductivity. The crosslinking agent promotes the formation of a three-dimensional network structure in the polymer, curing it into a rubber-like form. Catalysts can accelerate the curing reaction, thereby shortening the curing time. End-capping agents are used in the vinyl silicone oil end-capping reaction, enabling better preparation of dealcoholized condensation silicone rubber. In summary, the thermally conductive silicone rubber prepared from the thermally conductive silicone rubber composition of this application exhibits excellent storage stability, low viscosity, high thermal conductivity, and good adhesion, significantly reducing production costs.

[0111] The above are merely embodiments of the present invention and are not intended to limit the invention. Those skilled in the art will recognize that the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A thermally conductive silicone rubber composition, characterized in that, The thermally conductive silicone rubber composition comprises, by weight percentage: 1-30% vinyl silicone oil; 65-97% thermally conductive filler; 0.05~2% crosslinking agent; 0.001~1.5% catalyst; 0.25~1.5% surface treatment agent; 0.05~0.2% capping agent; The mass ratio of the surface treatment agent to the thermally conductive filler is 0.3~1:

100.

2. The thermally conductive silicone rubber composition according to claim 1, characterized in that, The thermally conductive silicone rubber composition comprises, by weight percentage: 3-25% of the aforementioned vinyl silicone oil; 75-95% of the thermally conductive filler; 0.1-1% of the crosslinking agent; 0.005~0.8% of the catalyst; 0.3~0.95% of the surface treatment agent; 0.05~0.15% of the capping agent.

3. The thermally conductive silicone rubber composition according to claim 1 or 2, characterized in that, The vinyl silicone oil is selected from any one or more of the following: polydimethylsiloxane with double-vinyl-terminated ends, polydimethylsiloxane with single-vinyl-terminated ends, polydimethylsiloxane with double-vinyl-terminated ends and side-chain vinyl-terminated ends, polydimethylsiloxane with double-methyl-terminated ends and side-chain vinyl-terminated ends, and branched vinyl-terminated ends; and / or, the vinyl content in the vinyl silicone oil is 0.1~1.0% by mass; and / or, the viscosity of the vinyl silicone oil is 50~1500 mPa·s. And / or, the capping agent is a siloxane compound containing a silane group, wherein the capping agent is selected from trimethoxysilane, dimethoxymethylsilane, H(CH3)2SiOSi(CH3)2(OSi(CH3)2). m -CH2CH2-Si(OCH3)3, H(CH3)2SiOSi(CH3)2(OSi(CH3)2) m Any one or more of -CH2CH2-SiCH3(OCH3)2; wherein m is any integer from 0 to 5; the molar ratio of the silanol group in the capping agent to the vinyl group in the vinyl silicone oil is 0.5 to 1:

1.

4. The thermally conductive silicone rubber composition according to any one of claims 1 to 3, characterized in that, The surface treatment agent is selected from any one or more of silazane, trialkoxysilane, and polydimethylsiloxanes with single-terminated trimethoxysilanes; wherein, the silazane is selected from any one or more of hexamethyldisilazane, 1,3-divinyltetramethyldisilazane, 1,3-di(trimethoxy)-tetramethyldisilazane, hexamethylcyclotrisilazane, and octamethylcyclotetrasilazane; the trialkoxysilane is selected from any one or more of propyltrimethoxysilane, octyltrimethoxysilane, decanyltrimethoxysilane, dodecyltrimethoxysilane, and hexadecyltrimethoxysilane; the chemical formula of the polydimethylsiloxane with single-terminated trimethoxysilanes is […]. n is 0~60; And / or, the thermally conductive filler is selected from any one or more of metal fillers, metal oxides, nitrides, carbides, and carbonaceous materials; wherein, the metal filler is selected from any one or more of gold, silver, copper, and aluminum; the metal oxide is selected from any one or more of aluminum oxide, zinc oxide, silicon dioxide, magnesium oxide, and titanium dioxide; the metal hydroxide is magnesium hydroxide and / or aluminum hydroxide; the nitride is selected from any one or more of boron nitride, aluminum nitride, boron nitride, and silicon nitride; the carbide is silicon carbide and / or boron carbide; and the carbonaceous material is selected from any one or more of diamond, graphite, fullerene, carbon nanotubes, and graphene.

5. The thermally conductive silicone rubber composition according to any one of claims 1 to 4, characterized in that, The crosslinking agent is an alkoxysilane, and the crosslinking agent is selected from any one or more of methyltrimethoxysilane, vinyltrimethoxysilane, propyltrimethoxysilane and butyltrimethoxysilane; And / or, the catalyst is an organotin catalyst and / or an organotitanium catalyst; wherein, the organotin catalyst is selected from any one or more of dibutyltin dilaurate, dibutyltin diacetate, tin dilaurate-decanate, and alkoxysilane-modified tin catalyst; and the organotitanium catalyst is selected from any one or more of isopropyl titanate, n-butyl titanate, tert-butyl titanate, ethyl acetoacetate chelated isopropyl titanate, and ethyl acetoacetate chelated n-butyl titanate. And / or, the thermally conductive silicone rubber composition further includes a coupling agent, the coupling agent having a mass content of 0.01~0.5%; the coupling agent is any one or more of the reaction product of alkoxysilane and aminosilane, aminosilane, acrylate silane, and alkoxysilane; wherein, the alkoxysilane is selected from any one or more of glycidyl ether propyltrimethoxysilane, glycidyl ether propyltriethoxysilane, and glycidyl ether propylmethyldimethoxysilane; the aminosilane is selected from any one or more of aminopropyltrimethoxysilane, aminopropyltriethoxysilane, aminoethylaminopropyltrimethoxysilane, aminoethylaminopropyltriethoxysilane, and aminosilane oligomers; the acrylate silane is methacryloxytrimethoxysilane and / or methacryloxytriethoxysilane.

6. The thermally conductive silicone rubber composition according to any one of claims 1 to 5, characterized in that, The thermally conductive silicone rubber composition further includes additives selected from any one or more of plasticizers, pigments, and thixotropic modifiers; wherein the mass content of the plasticizer is 0.01~1%; the mass content of the pigment is 0.01~1%; and the mass content of the thixotropic modifier is 0.01~1%.

7. A thermally conductive silicone rubber, prepared from a thermally conductive silicone rubber composition, characterized in that, The thermally conductive silicone rubber composition comprises any one of claims 1 to 6.

8. The thermally conductive silicone rubber according to claim 7, characterized in that, The thermal conductivity of the thermally conductive silicone rubber is 1.5~4 W / m·K; the viscosity of the thermally conductive silicone rubber is 15~55 Pa·s; after being stored at 25°C for 180 days, the viscosity of the thermally conductive silicone rubber is 15~55 Pa·s.

9. A method for preparing the thermally conductive silicone rubber according to claim 7 or 8, characterized in that, The preparation method includes: Step S1: Stir the vinyl silicone oil under vacuum to obtain stirred vinyl silicone oil; Step S2: Under a nitrogen atmosphere, the surface treatment agent is added to the stirred vinyl silicone oil, and the first mixing is carried out under a vacuum environment to obtain a first mixture; Step S3: Add the thermally conductive filler to the first mixture under a nitrogen atmosphere, and perform a second mixing under a vacuum environment to obtain a second mixture; Step S4: Heating is performed under a nitrogen atmosphere, and the second mixture is then subjected to a third mixing under a nitrogen atmosphere and a fourth mixing under a vacuum environment to obtain a third mixture; Step S5: After cooling the third mixture under vacuum, the capping agent is added to the third mixture under nitrogen atmosphere, followed by a fifth mixture under nitrogen atmosphere and a sixth mixture under vacuum to obtain a fourth mixture; and Step S6: Under a nitrogen atmosphere, the raw materials including the crosslinking agent and the catalyst are added to the fourth mixture, and then a seventh mixing is carried out in a vacuum environment to obtain the thermally conductive silicone rubber.

10. The preparation method according to claim 9, characterized in that, In step S1, the stirring temperature is 20~25℃ and the stirring time is 5~10min; And / or, in step S2, the temperature of the first mixing is 20~25℃, and the time of the first mixing is 5~10min; And / or, in step S3, the temperature of the second mixing is 20~150℃, and the time of the second mixing is 5~10min; And / or, in step S4, the temperature of the third mixing and the fourth mixing are each independently 130~150℃, and the time of the third mixing and the fourth mixing is each independently 30~60min; And / or, in step S5, the fifth mixing time is 30~60 min, the sixth mixing time is 5~20 min, and the temperatures of the fifth mixing and the sixth mixing are each independently 30~60℃; And / or, in step S6, the temperature of the seventh mixing is ≤50℃, and the time of the seventh mixing is 15~20min; and / or, the raw materials further include coupling agents and / or auxiliaries.

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