Heat-conducting silicone grease with high reliability and low thermal resistance and preparation method thereof

Abstract

The invention belongs to the technical field of thermal interface materials, and particularly relates to heat-conducting silicone grease with high reliability and ultralow thermal resistance and a preparation method of the heat-conducting silicone grease. Through special design of the raw material formula, the obtained heat-conducting silicone grease has the advantages of low heat resistance, high heat conductivity coefficient, high temperature aging resistance and the like, and can meet the requirements of high-power heat dissipation and high reliability in the fields of communication, automobile intelligent driving and the like.

Description

Technical Field

[0001] This invention belongs to the field of thermal interface materials technology, specifically relating to a thermally conductive silicone grease with high reliability (resistant to high temperature aging, low volatility) and ultra-low thermal resistance, and its preparation method. Background Technology

[0002] Because the microscopic gaps between electronic components and heat sinks contain air (with a thermal conductivity of only 0.026 W / m·K), they form a thermal conduction barrier, directly leading to device overheating, performance degradation, or even damage. Therefore, it is necessary to fill the different gaps between electronic components and heat sinks with thermally conductive interface materials to achieve efficient heat conduction between electronic components and heat sinks.

[0003] With the continuous increase in power density of 5G / 6G communications, artificial intelligence devices, high-performance computing chips (such as CPUs / GPUs), and new energy vehicle electronic control systems, the heat generation per unit volume has increased significantly, making traditional heat dissipation solutions insufficient. At the same time, the miniaturization of devices has led to a reduction in heat dissipation space (e.g., air cooling cannot be used inside optical modules), making it urgent to improve heat dissipation efficiency by filling microscopic gaps with efficient interface materials.

[0004] High-reliability, low-thermal-resistance thermal grease is a key material for addressing the contradiction between "high performance, miniaturization, and high reliability" in electronic devices. Its essential requirement is to solve three core problems: interface thermal resistance bottlenecks, lack of high-temperature stability, and insufficient heat dissipation redundancy in emerging scenarios. With breakthroughs in domestic technologies (such as filler modification, ultrafine powder, and liquid metal applications), this material is gradually supporting the heat dissipation security of strategic industries such as smart cars and computing hardware.

[0005] Developing highly reliable, low-thermal-resistance thermal greases requires careful consideration of filler composition and surface modification processes. Traditional thermal greases primarily use aluminum oxide, zinc oxide, boron nitride, and aluminum powder as thermal fillers. For example, CN116333497A discloses a thermal grease using zinc oxide and aluminum powder as thermal fillers, modified with n-decyltriethoxysilane, which can produce a thermal resistance of approximately 0.06℃·cm² / W and a thermal conductivity of approximately 5.0W / (mK), but the thermal conductivity is relatively low while the thermal resistance is relatively high. CN119072532A discloses a thermal grease using zinc oxide and gallium as thermal fillers, modified with alkoxysilane compounds, which can produce a thermal resistance of approximately 0.014℃·cm² / W and a thermal conductivity of approximately 12W / (mK), but its high and low temperature resistance is poor. Summary of the Invention

[0006] This invention provides a highly reliable, low-thermal-resistance thermal grease, which has advantages such as low thermal resistance, high thermal conductivity, and resistance to high-temperature aging.

[0007] The first technical problem to be solved by the present invention is to provide a highly reliable thermally conductive silicone grease with low thermal resistance, the raw materials of which include the following components in parts by weight: branched pre-gelled phenyl polysiloxane (component A) 1-20 parts, treatment agent (component B) 0.5-5 parts, thermally conductive filler (component CA) 150-500 parts, thermally conductive filler (component CB) 500-1000 parts, liquid metal (component D) 800-1500 parts, and antioxidant (component E) 0.5-5 parts.

[0008] Specifically, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the branched pre-gelled phenyl polysiloxane (component A) is obtained by addition reaction of phenyl vinyl polysiloxane and hydrogen-containing polysiloxane under the catalysis of a platinum-based catalyst.

[0009] Furthermore, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the phenyl vinyl polysiloxane is a polysiloxane having both silyl vinyl and phenyl groups.

[0010] Furthermore, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the structural formula of the phenylvinyl polysiloxane is:

[0011] Where 1≤n≤10.

[0012] Furthermore, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the vinyl content of the phenylvinyl polysiloxane is 0.15~3wt%. The viscosity of the phenylvinyl polysiloxane is 15~200 mPa·s.

[0013] Furthermore, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the structural formula of the hydrogen-containing polysiloxane is:

[0014] , where 10≤m≤50.

[0015] Furthermore, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the hydrogen content of the hydrogen-containing polysiloxane is 0.05~0.5wt%. The viscosity of the hydrogen-containing polysiloxane is 15~100 mPa·s. Preferably, the viscosity is 20~100 mPa·s.

[0016] Preferably, in the above-mentioned high-reliability, low-thermal-resistance thermal grease, the addition ratio of phenyl vinyl polysiloxane and hydrogen-containing polysiloxane is controlled to be 0.02-0.5, where the molar ratio of silane (silane in hydrogen-containing polysiloxane) to vinyl silane (vinyl silane in phenyl vinyl polysiloxane) is 0.02-0.5.

[0017] Specifically, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the platinum-based catalyst is a platinum-containing compound or its complex. For example, chloroplatinic acid or a complex of chloroplatinic acid and a vinyl-containing compound.

[0018] Specifically, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the platinum content in the platinum-based catalyst is 10-100 ppm.

[0019] Specifically, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the platinum catalyst in the addition reaction is 0.1-1% of the total weight of phenylvinyl polysiloxane and hydrogen-containing polysiloxane.

[0020] Preferably, in the above-mentioned high-reliability, low-thermal-resistance thermal grease, the viscosity of the branched pre-gelled phenyl polysiloxane is 30~300 mPa·s.

[0021] Specifically, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the treatment agent (component B) is one or more of the following: octyl organopolysiloxane (B-1), decanyl organopolysiloxane (B-2), or alkoxy organopolysiloxane (B-3).

[0022] Preferably, in the above-mentioned high-reliability, low-thermal-resistance thermal grease, the treatment agent (component B) is an alkoxy-containing organopolysiloxane (B-3). More preferably, it is a long-chain alkoxy-terminated polydimethylsiloxane.

[0023] Specifically, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the thermally conductive filler (component CA) is aluminum oxide and / or zinc oxide.

[0024] Preferably, in the above-mentioned high-reliability, low-thermal-resistance thermal grease, the thermally conductive filler (component CA) has a D50 of 0.1~1μm.

[0025] Preferably, in the above-mentioned high-reliability, low-thermal-resistance thermal grease, the thermally conductive filler (component CA) is at least one of zinc oxide (component C-1), single-crystal alumina (component C-2), and spherical alumina (component C-3).

[0026] More preferably, in the above-mentioned high-reliability, low-thermal-resistance thermal grease, the thermally conductive filler (component CA) is single-crystal alumina (component C-2).

[0027] Furthermore, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the single-crystal alumina (component C-2) has a D50 of 0.3~0.6μm.

[0028] Furthermore, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the zinc oxide (component C-1) has a D50 of 0.2~0.5μm.

[0029] Furthermore, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the spherical alumina (component C-3) has a D50 of 0.2~0.5μm.

[0030] Specifically, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the thermally conductive filler (component CB) is aluminum powder.

[0031] Preferably, in the above-mentioned high-reliability, low-thermal-resistance thermal grease, the thermally conductive filler (component CB) is aluminum powder, and the D50 of the aluminum powder is 1-15 μm, preferably 1-10 μm.

[0032] Furthermore, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the thermally conductive filler (component CB) is aluminum powder, which has three particle sizes: D50 of 1-2 μm aluminum powder (component C-4), D50 of 7-9 μm aluminum powder (component C-5), and D50 of 12-15 μm aluminum powder (component C-6), with any two of these sizes added. Preferably, the thermally conductive filler (component CB) contains aluminum powder with D50 of 1-2 μm (component C-4) and D50 of 7-9 μm aluminum powder (component C-5). More preferably, the thermally conductive filler (component CB) contains aluminum powder with D50 of 1-2 μm (component C-4) and D50 of 7-9 μm aluminum powder (component C-5), and the ratio of component C-5 to component C-4 is 1-4. Preferably, the ratio of component C-5 to component C-4 is 1 (by weight).

[0033] Specifically, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the liquid alloy (component D) is a gallium-based alloy. The gallium-based alloy is primarily composed of gallium, and is a eutectic alloy with one or more of indium, tin, zinc, or aluminum. Preferably, the melting point of the liquid metal is between -20 and 10°C. More preferably, the composition of the gallium-based alloy is 60-76 wt% gallium (Ga), 17-25 wt% indium (In), 5-20 wt% tin (Sn), and 1-10 wt% zinc (Zn).

[0034] Specifically, in the aforementioned high-reliability, low-thermal-resistance thermal grease, the antioxidant (component E) is a phenolic antioxidant. Preferably, the antioxidant (component E) is selected from antioxidant 1010 (E-1) and 4-methyl-6-tert-butylphenol (E-2). More preferably, the antioxidant (component E) is 4-methyl-6-tert-butylphenol (E-2).

[0035] The second technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned high-reliability, low-thermal-resistance thermal grease. The preparation method includes the following steps: treating the thermally conductive filler (component CA) with a treatment agent (component B), and then mixing, heating, and kneading the thermally conductive filler (component CB), branched pre-gelled phenyl polysiloxane (component A), liquid alloy (component D), and antioxidant (component E).

[0036] Furthermore, component B is diluted with a solvent, mixed with component CA, dried, and then mixed with components CB, A, D, and E, heated, and kneaded.

[0037] This invention provides an organosilicon-based thermal grease with high reliability (resistant to high-temperature aging and low volatility) and ultra-low thermal resistance. Through a special design of the raw material formulation, this invention results in a thermal grease with advantages such as low thermal resistance, high thermal conductivity, and resistance to high-temperature aging. Furthermore, by adding phenyl polysiloxane resistant to high and low temperatures, using a three-phase synergistic system of single-crystal alumina, aluminum powder, and liquid metal, combined with powder surface modification processes, a performance breakthrough is achieved with a thermal resistance below 0.02℃·cm² / W and a thermal conductivity >15W / (m·K). Moreover, it exhibits the advantage of not showing significant performance degradation during long-term aging at temperatures ranging from -20°C to 200°C. This invention's thermal grease meets the requirements of high-power heat dissipation and high reliability in the fields of communications and automotive intelligent driving. Attached Figure Description

[0038] Figure 1 Visual inspection of the fixture structure shows that the base plate is a polished aluminum plate and the front plate is glass.

[0039] Figure 2 Thermal resistance fixture structure diagram, in which the base plate is copper plated with nickel and the cover plate is aluminum plate;

[0040] Figure 3 a) is the appearance sample that passed the aging process (Example 4), b) is the appearance sample that cracked after aging (Comparative Example 1). Detailed Implementation

[0041] This invention discloses a highly reliable, low-thermal-resistance thermal grease, the raw materials of which include the following components in parts by weight: branched pre-gelled phenyl polysiloxane (component A) 1-20 parts, treatment agent (component B) 0.5-5 parts, thermally conductive filler (component CA) 150-500 parts, thermally conductive filler (component CB) 500-1000 parts, liquid metal (component D) 800-1500 parts, and antioxidant (component E) 0.5-5 parts.

[0042] In this invention, the branched pregelled phenyl polysiloxane (component A) is prepared by an addition reaction of phenyl vinyl polysiloxane and a hydrogen-containing polysiloxane crosslinking agent under the catalysis of a platinum catalyst. The branched pregelled polysiloxane with controllable crosslinking degree is formed by controlling the molar ratio of silane-hydrogen to silane-vinyl groups. A polysiloxane with silane-vinyl and phenyl structures and a viscosity of 15-200 mPa·s and a vinyl content of 0.15-3 wt% is selected. A hydrogen-containing polysiloxane crosslinking agent with a viscosity of 15-100 mPa·s and a hydrogen content of 0.05-0.5 wt% is selected. The amount of hydrogen-containing polysiloxane crosslinking agent added is adjusted to control the molar ratio of silane-hydrogen to silane-vinyl groups at 0.02-0.5. A platinum catalyst is added to prepare a branched pregelled phenyl polysiloxane with a viscosity of 30-300 mPa·s. If the ratio of silane to vinyl silane is <0.02, the branching degree of the pre-gelled polysiloxane is low, making it prone to oil seepage; if the ratio of silane to vinyl silane is >0.5, the crosslinking degree of the pre-gelled polysiloxane is high, and the gel solidification is unusable. The reaction mechanism of the branched pre-gelled phenyl polysiloxane (component A) of this invention is as follows:

[0043]

[0044] In this invention, the treatment agent (component B) is one or more of octyl-containing organopolysiloxanes (B-1), decanyl-containing organopolysiloxanes (B-2), or alkoxy-containing organopolysiloxanes (B-3). Preferably, the treatment agent (component B) is an alkoxy-containing organopolysiloxane (B-3).

[0045] In this invention, the thermally conductive filler (component C) comprises inorganic powder alumina and / or zinc oxide (component CA) and metallic powder aluminum powder (component CB). The median diameter D50 of the inorganic powder is 0.1~1μm. The median diameter D50 of the metallic powder is 1~15μm. If the particle size of the thermally conductive powder is too small, the thermal grease will be too thick, which is not conducive to the application of processes such as scraping; if the particle size of the thermally conductive powder is too large, the thermal grease's BLT will be too large, the adhesive layer will be difficult to thin, and the interfacial thermal resistance will be too high. The morphology of the thermally conductive filler can be single crystal, spherical, plate-like, needle-like, and other amorphous states.

[0046] In this invention, the thermally conductive filler (component CA) is at least one selected from zinc oxide (component C-1), single-crystal alumina (component C-2), and spherical alumina (component C-3). Preferably, the thermally conductive filler (component CA) is single-crystal alumina (component C-2). Further, the random zinc oxide (component C-1) has a D50 of 0.2~0.5μm (preferably 0.35μm) and a specific surface area of ​​approximately 3.5~7.0m². 2 / g (preferably 5.6m) 2 / g). Commercially available zinc oxide (zinc oxide ≥ 99.7%) can be produced using the Banana brand from Guangxi Liuzhou Zhongse Zinc Products Co., Ltd. Single-crystal alumina (component C-2) has a D50 of 0.3~0.6μm (preferably 0.5μm) and a specific surface area of ​​approximately 3.5~7.0m². 2 / g (preferably 4.1m) 2 / g). Commercial production can utilize Sumitomo AA-04 from Japan. Spherical alumina (component C-3), with a D50 of 0.2~0.5μm (preferably 0.3μm), and a specific surface area of ​​approximately 3.5~7.0m². 2 / g (preferably 5.1m) 2 / g). Commercialization can be achieved using MPA-04 from Ya'an Baitu High-Tech Materials Co., Ltd.

[0047] In this invention, the thermally conductive filler (component CB) is aluminum powder with three particle sizes: aluminum powder with a D50 of 1-2 μm (component C-4), aluminum powder with a D50 of 7-9 μm (component C-5), and aluminum powder with a D50 of 12-15 μm (component C-6). Any two of these can be added. Preferably, aluminum powder with a D50 of 1-2 μm (component C-4) and aluminum powder with a D50 of 7-9 μm (component C-5) are added. Further, spherical aluminum powder (component C-4) with a D50 of 1~2 μm (preferably 1.39 μm) has a specific surface area of ​​approximately 1.5~3.5 m². 2 / g (preferably 2.92m) 2 / g). Commercialization can utilize MAL-1-4C from Sichuan Weishi New Materials Technology Co., Ltd. Spherical aluminum powder (component C-5) has a D50 of 7~9μm (preferably 8.5μm) and a specific surface area of ​​approximately 0.4~0.7m². 2 / g (preferably 0.58m) 2 / g). Commercialization can utilize MAL-8-20C from Sichuan Weishi New Materials Technology Co., Ltd. Spherical aluminum powder (component C-6) with a D50 of 12~15μm (preferably 13.278μm) and a specific surface area of ​​approximately 0.3~0.6m². 2 / g (preferably 0.452m) 2 / g). For commercialization, FLPN14E from Henan Yuanyang Powder Co., Ltd. can be used.

[0048] In this invention, the liquid metal (component D) is a gallium-based alloy. The gallium-based alloy is a low-melting-point eutectic alloy formed with gallium (Ga) as the main component and one or more other metals (such as indium, tin, zinc, aluminum, etc.). The liquid metal preferably has a melting point of -20 to 10°C; if the melting point is too high, the silicone grease will have poor adhesive properties. Preferably, the composition of the gallium-based alloy is 60-76 wt% gallium (Ga), 17-25 wt% indium (In), 5-20 wt% tin (Sn), and 1-10 wt% zinc (Zn). Commercially, Hunan Rare Energy New Materials Co., Ltd.'s SNYT-100 can be used.

[0049] In this invention, the antioxidant (component E) is a phenolic antioxidant. Preferably, antioxidant component E is selected from antioxidant 1010 (component E-1) and 4-methyl-6-tert-butylphenol (component E-2). More preferably, it is 4-methyl-6-tert-butylphenol (component E-2).

[0050] The present invention discloses a method for preparing a highly reliable, low-thermal-resistance thermal grease, comprising the following steps:

[0051] 1) Powder processing:

[0052] Dilute the treatment agent (component B) with a solvent (e.g., anhydrous ethanol), add alumina (C-2, C-3) and / or zinc oxide (C-1) thermally conductive fillers to a high-speed disperser, turn on the high-speed disperser, and add the diluted treatment agent (component B) to the high-speed disperser in small amounts several times, stirring at high speed (e.g., for 6 hours). Then dry the treated thermally conductive powder (e.g., in an oven at 80°C for 4 hours). This step is to reduce the functional groups on the powder surface and increase the amount of powder added.

[0053] 2) Preparation of thermal grease:

[0054] Metallic aluminum powder (components C-4, C-5, C-6), treated thermally conductive fillers (C-1, C-2, C-3), branched pre-gelled phenyl polysiloxane (component A), liquid metal (component D), and antioxidant (component E) are added to a mixing device such as a kneader, heated (e.g., to 60~100℃), stirred evenly, and vacuum kneaded (e.g., kneaded for 4h~8h) to obtain the high-reliability, low-thermal-resistance thermally conductive silicone grease.

[0055] Example

[0056] Component A is prepared from phenyl polysiloxane (purchased from Shandong Dayi Chemical Co., Ltd.) with a viscosity of 50 mPa·s and a vinyl content of 1.9 wt%, side-containing hydrogen polysiloxane (purchased from Hesheng Silicon Industry Co., Ltd.) with a viscosity of 15 mPa·s and a silane hydrogen content of 0.25 wt%, and a platinum catalyst with a platinum content of 50 ppm, in a mass ratio of 100:2.5:0.8.

[0057] Component B-1 is octyltriethoxysilane (purchased from Shandong Silicon Science New Materials Co., Ltd.);

[0058] Component B-2 is decanyltrimethoxysilane (purchased from Hangzhou Jessco Chemical Co., Ltd.);

[0059] Component B-3, with both ends capped by long-chain alkoxy groups, has a kinematic viscosity of 35 mmHg at 25°C. 2 / s of polydimethylsiloxane (purchased from Hangzhou Jessco Chemical Co., Ltd.);

[0060] Component C-1 is random zinc oxide with a D50 of 0.35 μm and a specific surface area of ​​approximately 5.6 m². 2 / g;

[0061] Component C-2 is single-crystal alumina with a D50 of 0.5 μm and a specific surface area of ​​approximately 4.1 m². 2 / g;

[0062] Component C-3 is spherical alumina with a D50 of 0.3 μm and a specific surface area of ​​approximately 5.1 m². 2 / g;

[0063] Component C-4 is spherical aluminum powder with a D50 of 1.39 μm and a specific surface area of ​​approximately 2.92 m². 2 / g;

[0064] Component C-5 is spherical aluminum powder with a D50 of 8.5 μm and a specific surface area of ​​approximately 0.58 m². 2 / g;

[0065] Component C-6 is spherical aluminum powder with a D50 of 13.278 μm and a specific surface area of ​​approximately 0.452 m². 2 / g;

[0066] Component D is a Ga-In-Sn-Zn alloy (mass ratio = 62.0:25.0:11.0:2, melting point = 5°C);

[0067] Component E-1 is antioxidant 1010 (purchased from Shanghai Maclean Biochemical Technology Co., Ltd.).

[0068] Component E-2 is 4-methyl-6-tert-butylphenol (purchased from Hubei Wande Chemical Co., Ltd.).

[0069] Samples were prepared according to the proportions in Table 1 and the thermal grease preparation process, and then subjected to routine performance and reliability tests.

[0070] Table 1. Composition (parts by weight) of each component in each embodiment.

[0071]

[0072] Note: Thermal conductivity and thermal resistance were tested using the steady-state method ASTM D5470, viscosity was tested using the ASTM D4440 method, and D3~D10 were tested using the ASTM F2466-10 method.

[0073] Samples were prepared according to the proportions in Table 1 and the thermal grease preparation process, and then subjected to routine performance and reliability tests.

[0074] 1) Appearance deterioration reliability test

[0075] Use an external observation fixture (including a structural diagram of the sample, as shown in the image) Figure 1 As shown in Table 2), the sample preparation pressures for each example were 7 psi and 30 psi, and the number of samples for each example was 4. After aging tests on the samples in different examples, the slippage, hardening and cracking of the samples were observed. The test items and methods are shown in Table 2. The test results are shown in Table 4.

[0076] Table 2 Test Items and Methods for Vertical Flow Observation Fixture

[0077]

[0078] 2) Performance degradation reliability test

[0079] Take 50 mL of thermal grease sample and put it into a 100 mL glass bottle. After aging tests on the samples in different examples, use a thermal conductivity meter TIM LW-9389 (Taiwan Ruiling) to test the change in thermal conductivity of the samples before and after aging, according to the method of ASTM5470.

[0080] A thermal resistance testing fixture was used, with sample thicknesses of 0.3 mm. Four samples were used for each embodiment. After aging tests were conducted on the samples in different embodiments, the changes in thermal resistance before and after aging were tested using a TIM LW-9389 thermal conductivity meter (Taiwan Ruiling) according to the ASTM5470 method.

[0081] The test items and methods are shown in Table 3.

[0082] Table 3. Test Items and Methods for Thermal Conductivity and Thermal Resistance

[0083]

[0084] 3) Results of appearance degradation reliability test

[0085] The results of the appearance degradation reliability test are shown in Table 4:

[0086] Table 4 Results of Reliability Test for Appearance Deterioration

[0087]

[0088] 4) Results of reliability tests for performance degradation

[0089] The test results of thermal conductivity and thermal resistance in the performance degradation reliability test are shown in Tables 5 and 6:

[0090] Table 5 Results of thermal conductivity (λ) in reliability tests for performance degradation

[0091]

[0092] Table 6. Thermal resistance measurement results (0.3 mm) for performance degradation reliability test

[0093]

[0094] As can be seen from Examples 1-3 of this invention, the thermal grease prepared according to this invention, under the same powder filling ratio, shows lower viscosity and thermal resistance in the sample treated with alkoxy-containing organopolysiloxane (Example 3), and significantly higher thermal resistance in the sample using large-particle-size aluminum powder with a D50 of 13.278 μm (Example 6) than in the sample using small-particle-size aluminum powder with a D50 of 8.5 μm (Example 4). After reliability testing, the change rate of thermal resistance and thermal conductivity is <10%.

[0095] Example 7 (Comparative Example 1) does not contain component E-2, which may lead to poor stability of the liquid metal in the thermal grease, resulting in oxidation and cracking and hardening during aging. After aging, the thermal resistance change rate is ≥20%.

[0096] This specification is intended to be illustrative rather than restrictive. Based on this invention, those skilled in the art can make substitutions and modifications to some of the technical features without creative effort, and all such modifications are within the scope of protection of this invention.

Claims

1. A highly reliable, low-thermal-resistance thermal grease, characterized in that: Its raw materials include the following components in parts by weight: branched pregelated phenyl polysiloxane (component A) 1-20 parts, treatment agent (component B) 0.5-5 parts, thermally conductive filler (component CA) 150-500 parts, thermally conductive filler (component CB) 500-1000 parts, liquid metal (component D) 800-1500 parts, and antioxidant (component E) 0.5-5 parts.

2. The high-reliability, low-thermal-resistance thermal grease according to claim 1, characterized in that: The viscosity of the branched pregelled phenyl polysiloxane is 30~300 mPa·s; preferably, the branched pregelled phenyl polysiloxane (component A) is obtained by addition reaction of phenyl vinyl polysiloxane and hydrogen-containing polysiloxane under the catalysis of a platinum catalyst; further, the addition ratio of the phenyl vinyl polysiloxane and the hydrogen-containing polysiloxane is controlled to be 0.02-0.5, with the molar ratio of silane hydrogen (silane hydrogen in hydrogen-containing polysiloxane) to silyl vinyl (silyl vinyl in phenyl vinyl polysiloxane) controlled to be 0.02-0.

5.

3. The high-reliability, low-thermal-resistance thermal grease according to claim 2, characterized in that: The phenyl vinyl polysiloxane is a polysiloxane having silyl vinyl and phenyl groups; Furthermore, the structural formula of the phenylvinyl polysiloxane is: Where 1 ≤ n ≤ 10; Furthermore, the phenyl vinyl polysiloxane has a viscosity of 15~200 mPa·s and a vinyl content of 0.15~3 wt%.

4. The high-reliability, low-thermal-resistance thermal grease according to claim 2, characterized in that: The structural formula of the hydrogen-containing polysiloxane is: Where 10 ≤ m ≤ 50; Furthermore, the hydrogen-containing polysiloxane has a viscosity of 15~100 mPa·s and a hydrogen content of 0.05~0.5 wt%; preferably, the viscosity is 20~100 mPa·s.

5. The high-reliability, low-thermal-resistance thermal grease according to any one of claims 1-4, characterized in that: The treatment agent (component B) is one or more of octyl organopolysiloxane (B-1), decanyl organopolysiloxane (B-2), or alkoxy organopolysiloxane (B-3); preferably, the treatment agent (component B) is alkoxy organopolysiloxane (B-3).

6. The high-reliability, low-thermal-resistance thermal grease according to any one of claims 1-5, characterized in that: The thermally conductive filler (component CA) is alumina and / or zinc oxide; preferably, the thermally conductive filler (component CA) is at least one of zinc oxide (component C-1), single-crystal alumina (component C-2), and spherical alumina (component C-3); more preferably, the thermally conductive filler (component CA) is single-crystal alumina (component C-2). Preferably, the thermally conductive filler (component CA) has a D50 of 0.1~1μm; Furthermore, the D50 of the single-crystal alumina (component C-2) is 0.3~0.6μm.

7. The high-reliability, low-thermal-resistance thermal grease according to any one of claims 1-6, characterized in that: The thermally conductive filler (component CB) is aluminum powder; the D50 of the aluminum powder (component CB) is 1-15 μm; preferably 1-10 μm; Furthermore, the aluminum powder (component CB) has three particle size aluminum powders: aluminum powder with D50 of 1-2μm (component C-4), aluminum powder with D50 of 7-9μm (component C-5), and aluminum powder with D50 of 12-15μm (component C-6), and any two of them can be added; Preferably, the aluminum powder (component CB) is aluminum powder with a D50 of 1-2 μm (component C-4) and aluminum powder with a D50 of 7-9 μm (component C-5). More preferably, the thermally conductive filler (component CB) contains aluminum powder with a D50 of 1-2 μm (component C-4) and aluminum powder with a D50 of 7-9 μm (component C-5), and the ratio of component C-5 to component C-4 is 1-4; preferably, the ratio of component C-5 to component C-4 is 1.

8. The high-reliability, low-thermal-resistance thermal grease according to any one of claims 1-7, characterized in that: The liquid alloy (component D) is a gallium-based alloy; the gallium-based alloy is a eutectic alloy with one or more of indium, tin, zinc or aluminum as the main component; preferably, the melting point of the liquid metal is -20~10°C; more preferably, the composition of the gallium-based alloy is 60-76wt% gallium (Ga), 17-25wt% indium (In), 5-20wt% tin (Sn), and 1-10wt% zinc (Zn).

9. The high-reliability, low-thermal-resistance thermal grease according to any one of claims 1-8, characterized in that: The antioxidant (component E) is a phenolic antioxidant; preferably, the antioxidant (component E) is selected from antioxidant 1010 (E-1) and 4-methyl-6-tert-butylphenol (E-2); more preferably, the antioxidant (component E) is 4-methyl-6-tert-butylphenol (E-2).

10. A method for preparing the high-reliability, low-thermal-resistance thermal grease according to any one of claims 1-9, characterized in that: Includes the following steps: After treating the thermally conductive filler (component CA) with a treatment agent (component B), it is then mixed, heated, and kneaded with the thermally conductive filler (component CB), branched pre-gelled phenyl polysiloxane (component A), liquid alloy (component D), and antioxidant (component E).

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