Two-component high-thermal-conductivity ceramizable liquid silicone rubber

Abstract

The invention discloses bi-component high-thermal-conductivity ceramizable liquid silicone rubber. The liquid silicone rubber is prepared from a component A and a component B in a mass ratio of 1: 1, the component A is prepared from the following raw materials in parts by weight: 100 parts of a base material, 5 to 15 parts of a hydrogen-containing silicone oil cross-linking agent, 0.5 to 3 parts of a chain extender, 10 to 20 parts of vinyl modified polysilazane and 0.01 to 0.1 part of an inhibitor; the component B is prepared from the following raw materials in parts by weight: 100 parts of a base material, 10 to 20 parts of vinyl modified polysilazane and 0.5 to 3 parts of a catalyst. The bi-component high-thermal-conductivity ceramizable liquid silicone rubber disclosed by the invention has excellent fluidity, is easy to form, has a high thermal conductivity coefficient (up to 7w / m.k or above), can be encapsulated into extremely small gaps among electronic components, and avoids the situation that heat cannot be dissipated in time due to the existence of the gaps; the reaction is mild, room-temperature curing and high-temperature accelerated curing can be realized, and a silica gel layer cured under a high-temperature condition can form a compact ceramic layer and can bear 1500 DEG C high-temperature long-time baking without cracking and deformation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicone rubber, in particular to a two-component high-thermal-conductivity ceramifiable liquid silicone rubber. BACKGROUND

[0002] With the continuous rapid development of modern society, the popularization of 5G technology and the demand for 6G technology have become increasingly urgent, and the requirement for network speed is getting faster and faster, so the power of the core hardware will become larger and larger, and the heat generated will also become higher and higher; and at present, the global community is advocating a low-carbon environment, and the global penetration rate of new energy vehicles is rapidly increasing (expected to exceed 40% in 2025), but battery thermal runaway protection has become a core safety requirement. How to transfer the heat in the core components to the outside and block the further spread of the battery in the event of a fire has become a technical difficulty that the industry must solve. Traditional flame-retardant materials (such as mica tape and aerogel) are prone to melting and dripping at high temperatures, cannot form a continuous protective layer, and cannot provide high thermal conductivity to transfer the heat generated by internal components to the outside of the machine. If the internal heat cannot be discharged in time, it will further age the internal components, reducing the service life, and even cause a short circuit, resulting in a self-ignition phenomenon. Therefore, in order to solve the above problems, combined with the performance comparison of the same type of liquid silicone rubber on the market, such as the ceramifiable silicone rubber involved in Chinese patent CN113881233A, the compressive strength is only 15Mpa, which is far from meeting the use requirements, and the thermal conductivity is almost zero, so the use scenario is relatively single. The present application belongs to the technical field of high polymer materials, and specifically relates to a two-component liquid silicone rubber composition with high thermal conductivity, high temperature resistance, ceramifiable properties and excellent processing performance, which is suitable for new energy vehicle battery sealing and 5G communication equipment protection scenarios. SUMMARY

[0003] In order to overcome the shortcomings and deficiencies of the prior art, the primary purpose of the present application is to provide a two-component high-thermal-conductivity ceramifiable liquid silicone rubber. The present application mainly adds a combination of self-made surface-modified metal powder and metal nitride filler to give it high thermal conductivity and excellent flowability, and then introduces a vinyl-modified polysilazane to form a dense ceramic layer at a specific temperature. Another purpose of the present application is to provide the above-mentioned two-component high-thermal-conductivity ceramifiable liquid silicone rubber.

[0004] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a two-component high-thermal-conductivity ceramifiable liquid silicone rubber, which is prepared from A component and B component in a mass ratio of 1:1; The A component is composed of the following raw materials by weight: 100 parts of base material, hydrogen-containing silicone oil crosslinking agent 5-15 parts, chain extender 0.5-3 parts, vinyl-modified polysilazane 10-20 parts, inhibitor 0.01-0.1 parts, The B component is composed of the following raw materials by weight parts: base 100 parts, vinyl-modified polysilazane 10-20 parts, catalyst 0.5-3 parts, The base of the A, B components is composed of the following raw materials by weight parts: a, w-divinyl polydimethylsiloxane 100 parts, self-made filler 100-500 parts.

[0005] Preferably, the above-mentioned two-component high-thermal-conductivity ceramicizable liquid silicone rubber, wherein the hydrogen-containing silicone oil crosslinking agent is a branched hydrogen-containing silicone oil, and the hydrogen content is 0.10%-0.56% by mass percentage.

[0006] Preferably, the above-mentioned two-component high-thermal-conductivity ceramicizable liquid silicone rubber, wherein the chain extender is a double-end hydrogen-containing silicone oil, and the hydrogen content is 0.05%-0.1% by mass percentage.

[0007] Preferably, the above-mentioned two-component high-thermal-conductivity ceramicizable liquid silicone rubber, wherein the inhibitor is one of 1-ethynyl-cyclohexanol, 2-methyl-3-butynyl-2-alcohol, 2-methyl-1-hexynyl-3-alcohol, 3,5-dimethyl-1-ethynyl-3-alcohol, and 3,7,11-trimethyl-1-dodecynyl-3-alcohol.

[0008] Preferably, the above-mentioned two-component high-thermal-conductivity ceramicizable liquid silicone rubber, wherein the catalyst is one of platinum vinylsiloxane, platinum-alkyne-based chelate, and chloroplatinic acid, and the platinum content is 1000-5000 ppm.

[0009] Preferably, the above-mentioned two-component high-thermal-conductivity ceramicizable liquid silicone rubber, wherein the a, w-divinyl polydimethylsiloxane has a viscosity of 50-1000 mpa.s at 25°C, and a vinyl content of 0.1%-0.4% by mass ratio.

[0010] Preferably, the two-component high-thermal-conductivity ceramizable liquid silicone rubber described above, wherein the vinyl-modified polysilazane is a high-performance material chemically modified by introducing vinyl groups into polysilazane (PSZ), the core feature of which is that the introduction of vinyl groups significantly improves the physical properties and chemical adaptability of the material, the viscosity is 50-1000 mpa.s, the vinyl content is 0.1-1.5% by mass, and the position of the vinyl group is one or a combination of end or side chain.

[0011] Preferably, the two-component high-thermal-conductivity ceramizable liquid silicone rubber described above, wherein the filler is a mixture of self-made surface-modified metal powder and metal nitride, the ratio of metal powder to metal nitride powder is 1-3:3-8, wherein the metal powder is one or a combination of copper powder, aluminum powder, silver powder, nickel powder, and iron powder, and the particle size is 5-25 μm, and the metal nitride is one or a combination of aluminum nitride, zinc nitride, magnesium nitride, and titanium nitride, and the particle size is 20-50 μm, wherein the self-made filler can be obtained by the following method: mixing at least one or more metal powders with one or more metal nitride powders in a ratio of 1-3:3-8, fully mixing them with hexamethyldisilazane and deionized water in a ratio of 10:2:1 in a mixer at room temperature, then increasing the temperature to 140-160°C and continuing to mix for 2 h to obtain the filler required by the present application.

[0012] Compared with the prior art, the two-component high-thermal-conductivity ceramizable liquid silicone rubber of the present application has the following advantages: it has excellent flowability, is easy to shape, has a high thermal conductivity of more than 7 w / m.k, can be filled into the smallest gap between electronic components, and avoids the problem that heat cannot be dissipated in time due to the existence of the gap; it can be cured at room temperature or accelerated at high temperature, and the cured silicone layer can form a dense ceramic layer that can withstand high-temperature baking of 1500°C for a long time without cracking or deformation, and has great market application prospects. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the embodiments of the present application will be described below in conjunction with the embodiments, obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application. Embodiment 1

[0014] A two-component high-thermal-conductivity ceramizable liquid silicone rubber is prepared by the following method: (1) Take 100 parts of a,w-divinyl polydimethylsiloxane with viscosity of 100 mPa.s and vinyl content of 0.3%, 400 parts of self-made filler, add them into a stirring machine, dehydrate and stir for 2 hours at 120°C to make a base material, which contains 100 parts of copper powder with particle size of 5 μm and 300 parts of aluminum nitride with particle size of 20 μm.

[0015] (2) Take 100 parts of the base material prepared in step (1), cool to room temperature, and then add 8 parts of hydrogen-containing silicone oil crosslinking agent with hydrogen content of 0.36%, 1.0 part of chain extender with terminal hydrogen content of 0.05%, 10 parts of end-chain vinyl modified polysilazane with viscosity of 50 mPa.s and vinyl content of 0.1%, and 0.05 part of inhibitor 1-ethynyl-cyclohexanol in sequence, stir uniformly in a stirring machine, and vacuum degassing to prepare component A.

[0016] (3) Take 100 parts of the base material prepared in step (1), cool to room temperature, and then add 0.5 part of platinum-alkyne chelate as catalyst with platinum content of 3000 ppm, and 10 parts of end-chain vinyl modified polysilazane with viscosity of 50 mPa.s and vinyl content of 0.1%, stir uniformly in a stirring machine, and vacuum degassing to prepare component B. Example 2

[0017] A two-component high-thermal-conductivity ceramicizable liquid silicone rubber is prepared by the following method: (1) Take 100 parts of a,w-divinyl polydimethylsiloxane with viscosity of 500 mPa.s and vinyl content of 0.4%, 200 parts of self-made filler, add them into a stirring machine, dehydrate and stir for 2 hours at 120°C to make a base material, which contains 40 parts of silver powder with particle size of 10 μm and 160 parts of aluminum nitride with particle size of 25 μm.

[0018] (2) Take 100 parts of the base material prepared in step (1), cool to room temperature, and then add 8 parts of hydrogen-containing silicone oil crosslinking agent with hydrogen content of 0.36%, 1.0 part of chain extender with terminal hydrogen content of 0.05%, 10 parts of end-chain vinyl modified polysilazane with viscosity of 50 mPa.s and vinyl content of 0.1%, and 0.05 part of inhibitor 1-ethynyl-cyclohexanol in sequence, stir uniformly in a stirring machine, and vacuum degassing to prepare component A.

[0019] (3) Take 100 parts of the base material prepared in step (1), cool to room temperature, and then add 0.5 part of platinum-alkyne chelate as catalyst with platinum content of 3000 ppm, and 10 parts of end-chain vinyl modified polysilazane with viscosity of 50 mPa.s and vinyl content of 0.1%, stir uniformly in a stirring machine, and vacuum degassing to prepare component B. Example 3

[0020] A two-component high-thermal-conductivity ceramifiable liquid silicone rubber is prepared by the following method: (1) 100 parts of a,w-divinyl polydimethylsiloxane with a viscosity of 100 mPa.s and a vinyl content of 0.3%, 400 parts of a self-made filler, are added into a stirring machine, and dehydrated and stirred at 120°C for 2 hours to make a base material, which contains 100 parts of copper powder with a particle size of 5 μm and 300 parts of aluminum nitride with a particle size of 20 μm.

[0021] (2) 100 parts of the base material prepared in step (1) are cooled to room temperature, and then 8 parts of a hydrogen-containing silicone oil crosslinking agent with a hydrogen content of 0.36%, 1.0 part of a chain-extending agent with a terminal hydrogen content of 0.05%, and 20 parts of a side-chain vinyl-modified polysilazane with a viscosity of 300 mPa.s and a vinyl content of 0.5% are added in sequence, and 1-ethynyl-cyclohexanol 0.05 parts as an inhibitor is added, and the mixture is stirred uniformly in a stirring machine and vacuum-deaerated to prepare component A.

[0022] (3) 100 parts of the base material prepared in step (1) are cooled to room temperature, and then 1.0 part of a platinum-alkyne-based chelate with a platinum content of 3000 ppm and 20 parts of a side-chain vinyl-modified polysilazane with a viscosity of 300 mPa.s and a vinyl content of 0.5% are added, and the mixture is stirred uniformly in a stirring machine and vacuum-deaerated to prepare component B. Comparative Example 1 A two-component high-thermal-conductivity ceramifiable liquid silicone rubber is prepared by the following method:

[0023] (1) 100 parts of a,w-divinyl polydimethylsiloxane with a viscosity of 100 mPa.s and a vinyl content of 0.3%, 400 parts of a filler without modification, are added into a stirring machine, and dehydrated and stirred at 120°C for 2 hours to make a base material, which contains 100 parts of copper powder without modification with a particle size of 5 μm and 300 parts of aluminum nitride powder without modification with a particle size of 20 μm.

[0024] (2) 100 parts of the base material prepared in step (1) are cooled to room temperature, and then 8 parts of a hydrogen-containing silicone oil crosslinking agent with a hydrogen content of 0.36%, 1.0 part of a chain-extending agent with a terminal hydrogen content of 0.05%, and 10 parts of a terminal-chain vinyl-modified polysilazane with a viscosity of 50 mPa.s and a vinyl content of 0.1% are added in sequence, and 1-ethynyl-cyclohexanol 0.05 parts as an inhibitor is added, and the mixture is stirred uniformly in a stirring machine and vacuum-deaerated to prepare component A.

[0025] (3) Take the base material prepared in step (1) 100 parts, cool to room temperature, add catalyst for platinum-acetylene base chelate, platinum content 3000ppm 0.5 parts, viscosity 50mpa.s, vinyl content 0.1% of end chain vinyl modified polysilazane 10 parts, stirring in the blender, vacuum degassing, prepared B component. Comparative Example 2 A two-component high-thermal-conductivity ceramifiable liquid silicone rubber is prepared by the following method:

[0026] (1) a, w-di-vinyl polydimethylsiloxane 100 parts with viscosity 500mpa.s, vinyl content 0.4%, self-made filler 200 parts, add to the blender, dehydrate stirring at 120℃ for 2 hours, make into base material, wherein the self-made filler contains only silver powder 200 parts, particle size 10μm.

[0027] (2) Take the base material prepared in step (1) 100 parts, cool to room temperature, add hydrogen-containing silicone oil crosslinking agent 8 parts with hydrogen content 0.36% by mass percentage, end hydrogen-containing chain extender 1.0 parts with hydrogen content 0.05% by mass percentage, end chain vinyl modified polysilazane 10 parts with viscosity 50mpa.s, vinyl content 0.1%, inhibitor 1-ethynyl-cyclohexanol 0.05 parts, stirring in the blender, vacuum degassing, prepared A component.

[0028] (3) Take the base material prepared in step (1) 100 parts, cool to room temperature, add catalyst for platinum-acetylene base chelate, platinum content 3000ppm 0.5 parts, end chain vinyl modified polysilazane 10 parts with viscosity 50mpa.s, vinyl content 0.1%, stirring in the blender, vacuum degassing, prepared B component. Comparative Example 3 A two-component high-thermal-conductivity ceramifiable liquid silicone rubber is prepared by the following method:

[0029] (1) a, w-di-vinyl polydimethylsiloxane 100 parts with viscosity 100mpa.s, vinyl content 0.3%, self-made filler 400 parts, add to the blender, dehydrate stirring at 120℃ for 2 hours, make into base material, wherein contains copper powder 100 parts, particle size 5μm, aluminum nitride 300 parts, particle size 20μm.

[0030] (2) Take the base material prepared in step (1) 100 parts, cool to room temperature, add hydrogen-containing silicone oil crosslinking agent 8 parts with hydrogen content 0.36% by mass percentage, end hydrogen-containing chain extender 1.0 parts with hydrogen content 0.05% by mass percentage, inhibitor 1-ethynyl-cyclohexanol 0.05 parts, stirring in the blender, vacuum degassing, prepared A component.

[0031] (3) Take 100 parts of the base material prepared in step (1), cool to room temperature, add 1.0 parts of platinum-alkyne-based chelate as a catalyst, with a platinum content of 3000 ppm, stir uniformly in a blender, and vacuum degassing to prepare component B.

[0032] Comprehensive performance test of products of each example and comparative example: The above each example and comparative example is mixed uniformly according to a mass ratio of 1:1, and the gas bubbles are removed under vacuum conditions. The viscosity after mixing is tested according to the test method of national standard GB / T 13354; after complete curing, the thermal conductivity of each sample is tested according to the test method of international standard ISO22007-2-2015, and the ceramic conversion rate of each sample is tested using a thermogravimetric method according to GB / T27761.

[0033] Table 1 is a comparison table of the mixed viscosity and volume resistivity of the high-heat-dissipation high-conductivity silicone potting adhesive prepared in examples 1-4 and comparative examples 1-2 under room temperature conditions: Item Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Viscosity, mPa.s 6000 4500 5700 80000 3200 6500 Ceramic conversion, 100% 83.5 85.6 84.3 82.6 83.8 0 Thermal conductivity, W / m-K 8.05 7.53 8.15 7.35 4.35 7.88 Table 1

[0034] As can be seen from Table 1, the liquid silicone rubber prepared in examples 1-3 has excellent flowability, high thermal conductivity and high ceramic conversion rate. The comparison of data of example 1 and comparative example 1 shows that the self-made treated filler can exactly reduce the viscosity and help to improve the thermal conductivity; the comparison of data of example 2 and comparative example 2 shows that there is a big difference in thermal conductivity between the single powder and the combined powder filler, and the thermal conductivity of the combined powder filler is much higher than that of the single powder filler; the comparison of data of example 3 and comparative example 3 shows that the vinyl-modified polysilazane plays a decisive role in the ceramic conversion of the system, and if there is no vinyl-modified polysilazane in the system, the system cannot be successfully converted into a ceramic layer under high temperature conditions.

[0035] The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as limiting the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A two-component high-thermal-conductivity ceramifiable liquid silicone rubber, which is prepared from an A component and a B component in a mass ratio of 1:

1. The A component is composed of the following raw materials in parts by weight: 100 parts of a base, 5-15 parts of a hydrogen-containing silicone oil crosslinking agent, 0.5-3 parts of a chain extender, 10-20 parts of a vinyl-modified polysilazane, and 0.01-0.1 parts of an inhibitor. The B component is composed of the following raw materials in parts by weight: 100 parts of a base, 10-20 parts of a vinyl-modified polysilazane, and 0.5-3 parts of a catalyst. The base of the A and B components is composed of the following raw materials in parts by weight: 100 parts of a,w-divinyl polydimethylsiloxane, and 100-500 parts of a self-made filler. The hydrogen-containing silicone oil crosslinking agent is a branched hydrogen-containing silicone oil with a hydrogen content of 0.10%-0.56% by mass. The chain extender is a double-end hydrogen-containing silicone oil with a hydrogen content of 0.05%-0.1% by mass. The inhibitor is one of 1-ethynyl-cyclohexanol, 2-methyl-3-butynyl-2-alcohol, 2-methyl-1-hexynyl-3-alcohol, 3,5-dimethyl-1-ethynyl-3-alcohol, and 3,7,11-trimethyl-1-dodecynyl-3-alcohol. The catalyst is one of platinum vinylsiloxane, platinum-alkyne-based chelate, and chloroplatinic acid, with a platinum content of 1000-5000 ppm. The a,w-divinyl polydimethylsiloxane has a viscosity of 50-1000 mpa.s at 25°C and a vinyl content of 0.1%-0.4% by mass. The vinyl-modified polysilazane is a high-performance material obtained by chemically modifying polysilazane (PSZ) by introducing vinyl groups, and its core feature is that the physical properties and chemical adaptability of the material are significantly improved by the introduction of vinyl groups, with a viscosity of 50-1000 mpa.s, a vinyl content of 0.1-1.5% by mass, and vinyl groups in one or more combinations of terminal or side chain positions. The filler is a mixture of self-made surface-active modified metal powder and metal nitride, with a ratio of metal powder to metal nitride powder of 1-3:3-8, wherein the metal powder is one or more combinations of metal copper powder, metal aluminum powder, metal silver powder, metal nickel powder, and metal iron powder, with a particle size of 5-25 μm, and the metal nitride is one or more combinations of aluminum nitride, zinc nitride, magnesium nitride, and titanium nitride, with a particle size of 20-50 μm. The self-made filler can be obtained by mixing at least one or more metal powders with one or more metal nitride powders in a ratio of 1-3:3-8, fully mixing them with hexamethyldisilazane and deionized water in a mass ratio of 10:2:1 in a mixer at room temperature, then increasing the temperature to 140°C-160°C and continuing to mix for 2 h to obtain the filler required by the application. ​ ​ 2. The two-component high thermal conductive ceramifiable liquid silicone rubber according to claim 1, characterized in that: ​ 3. The two-component high thermal conductive ceramifiable liquid silicone rubber according to claim 1, characterized in that: ​ 4. The two-component high thermal conductive ceramifiable liquid silicone rubber according to claim 1, characterized in that: ​ 5. The two-component high thermal conductive ceramifiable liquid silicone rubber according to claim 1, characterized in that: ​ 6. The two-component high thermal conductive ceramifiable liquid silicone rubber according to claim 1, characterized in that: ​ 7. The two-component high thermal conductive ceramifiable liquid silicone rubber according to claim 1, characterized in that: ​ ​ 8. The two-component high thermal conductive ceramifiable liquid silicone rubber according to claim 1, characterized in that: ​