A spherical aluminum nitride silicon grease high thermal conductive interface material composition

Abstract

The application discloses a spherical aluminum nitride silicon grease high-thermal-conductivity interface material composition and belongs to the technical field of thermal-conductivity interface materials.The spherical aluminum nitride silicon grease high-thermal-conductivity interface material composition comprises, in terms of weight parts, 50-80 parts of spherical aluminum nitride and 50-100 parts of modified silicon oil, the modified silicon oil is silicon oil grafted with adamantane molecules and fluorine-containing alkyl groups on the side chain, and the spherical aluminum nitride is prepared by using aluminum powder with low, medium and high particle sizes, wherein the spherical structure guarantees the fluidity of the silicon grease, the introduction of the adamantane molecules and the perfluoroalkyl molecules improves the heat resistance of the silicon oil and reduces the migration rate of the silicon oil, different particle sizes of the spherical aluminum nitride are used in combination for compounding, the filler with a smaller particle size can fill the gaps between the fillers with a larger particle size, a more perfect thermal-conductivity channel is constructed, the gap rate between the filler particles is greatly reduced, and the thermal-conductivity performance of the material is improved.

Description

Technical Field

[0001] This invention relates to the field of thermal interface materials technology, specifically to a spherical aluminum nitride silicone grease high thermal conductivity interface material composition. Background Technology

[0002] With the rapid development of industries such as 5G, chips, and new energy, the power of electronic components is increasing, and the resulting heat accumulation has become one of the key issues restricting their rapid development. Using heat dissipation components can accelerate the heat dissipation process of electronic components. However, due to surface flatness issues, the area of ​​direct contact between heat-generating electronic components and heat dissipation components is relatively small, resulting in a high porosity. These gaps are mostly filled with air, and air has a thermal conductivity of only 0.023 W / (m·K), leading to a large contact thermal resistance between the heat-generating electronic components and heat dissipation components, making heat dissipation difficult. Filling the space between them with a thermally conductive interface material is an effective means to reduce contact thermal resistance and enhance heat dissipation. Thermally conductive interface materials possess thermal conductivity and high ductility, ensuring long-term efficient operation of the devices.

[0003] Organosilicon materials possess advantages such as insulation, fatigue resistance, chemical stability, and ease of processing, making them ideal matrix materials for thermally conductive interfaces. However, the thermal conductivity of ordinary organosilicon is typically below 0.3 W / (m·K). Generally, sufficient thermally conductive fillers need to be added to the organosilicon matrix to form effective thermal conduction paths and networks, allowing phonons to be transmitted along these paths or networks. However, excessive addition of thermally conductive fillers increases the viscosity of the thermal grease, hindering filler dispersion and affecting its applicability. Furthermore, existing thermal greases, when exposed to high-temperature environments for extended periods, exhibit liquid migration after a period of use. Oil stains "secrete" between the device and the heat sink, a phenomenon known as thermal grease seepage. This seepage can corrode surrounding electronic components, contaminate optical parts, and in severe cases, cause equipment failure. The remaining grease may dry out and harden, failing to effectively fill the gaps between the heat source and the heat sink, thus reducing heat dissipation. Generally, the amount of oil seepage in thermally conductive interface materials decreases with increasing crosslinking density, filler fraction, and silicone oil molecular weight. Higher crosslinking density, filler fraction, and silicone oil molecular weight result in lower migration. However, this also increases the viscosity of the thermal grease, making it unsuitable for certain applications. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a spherical aluminum nitride silicone grease high thermal conductivity interface material composition.

[0005] The technical solution for achieving the objective of this invention is as follows:

[0006] A high thermal conductivity interface material composition for spherical aluminum nitride silicone grease, comprising, by weight, 50-85 parts of spherical aluminum nitride and 15-50 parts of modified silicone oil, wherein the modified silicone oil is silicone oil with adamantane molecules and fluorinated alkyl groups grafted onto its side chains, the modified silicone oil comprising 60-80% star-shaped silicone oil and 20-40% linear silicone oil, the number average molecular weight of the star-shaped silicone oil being 15000-40000 g / mol, and the number average molecular weight of the linear silicone oil being 5000-8000 g / mol; the spherical aluminum nitride is a blend of low-particle-size spherical aluminum nitride, medium-particle-size spherical aluminum nitride, and high-particle-size spherical aluminum nitride.

[0007] In one specific embodiment, the spherical aluminum nitride is further surface-treated with a silane coupling agent.

[0008] In one specific embodiment, the low-particle-size spherical aluminum nitride has a particle size of 1–2 μm; the medium-particle-size spherical aluminum nitride has a particle size of 4–6 μm; and the high-particle-size spherical aluminum nitride has a particle size of 9–11 μm.

[0009] In one specific embodiment, the silane coupling agent is an aminosilane coupling agent.

[0010] In one specific embodiment, the mass ratio of low-diameter spherical aluminum nitride, medium-diameter spherical aluminum nitride, and high-diameter spherical aluminum nitride is (4-6):(2-3):(1-3).

[0011] In one specific embodiment, the spherical aluminum nitride is prepared by heating low-particle-size atomized spherical aluminum powder, medium-particle-size atomized spherical aluminum powder, and high-particle-size atomized spherical aluminum powder to 1000-1300°C at a heating rate of 5-10°C / min and holding at that temperature for 60-120 minutes under continuous nitrogen gas purging.

[0012] In one specific embodiment, the modified silicone oil is prepared by:

[0013] S1. Methylcyclosiloxane, 2,4,6,8-tetra(β-adamantaneethyl)tetramethylcyclotetrasiloxane, 1,3,5-trimethyl-1,3,5-tris(3,3,3-trifluoropropyl)cyclotrisiloxane monomers and a portion of the end-capping agent were dissolved in toluene. The system was purged with nitrogen to remove oxygen. The catalyst was prepared into a solution. Under a nitrogen atmosphere, the catalyst solution was added dropwise to the reaction system at room temperature. The mixture was first heated and stirred at 25–30°C, then heated to 70–90°C and maintained for 2–4 hours. Finally, the temperature was lowered to 50–70°C, the remaining end-capping agent was added, and stirring was continued for 1 hour. The catalyst and solvent were removed, and the mixture was filtered to obtain linear silicone oil.

[0014] S2. Linear silicone oil, anhydrous toluene, and tetramethyltetravinylcyclotetrasiloxane are pre-dried using molecular sieves. The linear silicone oil and anhydrous toluene are added to a reaction vessel, and oxygen is removed by nitrogen purging. Under a nitrogen atmosphere, tetramethyltetravinylcyclotetrasiloxane and ethynylcyclohexanol, equivalent to 15-20% molar parts of the linear silicone oil, are added and stirred at room temperature until completely dissolved. The reaction system is placed in an ice bath at 0-5°C, and Karstedt catalyst is injected. The mixture is stirred evenly and kept at this temperature for a period of time. The ice bath is removed, and the temperature is programmed to rise to 30-40°C and held for 1-3 hours, then held at 50-60°C for 0.5-2 hours. After the reaction is completed, a mixture of star-shaped silicone oil and linear silicone oil is purified to obtain the modified silicone oil.

[0015] In one specific embodiment, the methylcyclosiloxane is selected from one or more of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane; the end-capping agent is selected from tetramethyldisiloxane; and the catalyst is selected from one or two of tetramethylammonium hydroxide silanolate and tetraethylammonium hydroxide silanolate.

[0016] In one specific embodiment, the preparation method of 2,4,6,8-tetramethylcyclotetrasiloxane is as follows: 2,4,6,8-tetramethylcyclotetrasiloxane and 1-vinyladamantane are pre-dried and purified. Under strictly anhydrous and oxygen-free conditions, 2,4,6,8-tetramethylcyclotetrasiloxane and anhydrous toluene are added to a reaction vessel. Oxygen is removed by nitrogen purging. Under a nitrogen atmosphere, 1-vinyladamantane is slowly added and stirred evenly. The reaction system is placed in an ice bath at 0-5°C, and Karstedt catalyst is injected. After stirring for a period of time, the ice bath is removed, and the temperature is gradually increased to 60-80°C and held for 1-3 hours. The catalyst is removed, and the mixture is filtered. The solvent is removed by vacuum distillation to obtain 2,4,6,8-tetramethylcyclotetrasiloxane.

[0017] This invention also protects a method for preparing the spherical aluminum nitride silicone grease high thermal conductivity interface material composition, comprising the following steps:

[0018] (1) Surface treatment of spherical aluminum nitride using silane coupling agent;

[0019] (2) Add spherical aluminum nitride surface-treated with silane coupling agent to modified silicone oil, stir and mix in a mixer, and discharge after vacuuming to obtain spherical aluminum nitride silicone grease to a high thermal conductivity interface material composition.

[0020] Beneficial effects

[0021] This invention provides a spherical aluminum nitride silicone grease high thermal conductivity interface material composition. The modified silicone oil is a silicone oil with adamantane molecules and fluorinated alkyl groups grafted onto its side chains. Specifically, a mixture of high-molecular-weight star-shaped silicone oil and low-molecular-weight linear silicone oil is used. The low-molecular-weight linear silicone oil can reduce overall viscosity and improve wettability, while the high-molecular-weight star-shaped silicone oil can lock in fillers and reduce high-temperature oil leakage. Furthermore, the rigid cage-like framework of adamantane introduced into the silicone oil molecular chain can form nanoscale hard fulcrums at the silicone oil-filler interface. Simultaneously, its CC framework vibration matches the low-frequency phonon spectrum, acting as a phonon relay station and reducing interfacial thermal resistance. At the same time, the rigid steric hindrance of adamantane increases polymer molecular chain entanglement, resulting in greater friction and resistance during molecular diffusion, effectively inhibiting silicone oil migration. The introduction of fluorinated alkyl groups increases the contact angle between the silicone oil and heat-generating electronic components, reduces the surface energy of the silicone oil, and decreases contact failure of electronic components caused by silicone oil migration. The residual Si-H end groups in the modified silicone oil can react with the amino groups of the silane coupling agent on the filler surface at high temperatures, further anchoring the silicone oil and filler and reducing oil leakage at high temperatures. Furthermore, spherical aluminum nitride is prepared using aluminum powder with low, medium, and high particle sizes. The spherical structure ensures the fluidity of the silicone grease, while the introduction of adamantane and fluorinated alkyl molecules improves the heat resistance of the silicone oil and reduces its migration rate. When combined with spherical aluminum nitride of different particle sizes, smaller particle sizes can fill the gaps between larger particle sizes, creating a more complete thermal conductivity pathway, significantly reducing the porosity between filler particles, and improving the thermal conductivity of the material. Attached Figure Description

[0022] Figure 1 A schematic diagram of the synthetic route for 2,4,6,8-tetra(β-adamantaneethyl)tetramethylcyclotetrasiloxane;

[0023] Figure 2 A schematic diagram of the synthetic route for modified silicone oil;

[0024] Figure 3 The 1H NMR spectrum of 2,4,6,8-tetra(β-adamantaneethyl)tetramethylcyclotetrasiloxane;

[0025] Figure 4 Infrared spectra of modified silicone oil 1, linear silicone oil 1, and linear silicone oil 8. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] Unless otherwise specified, the experimental methods used in the embodiments are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0028] The raw materials used in the examples and comparative examples are described below:

[0029] Low-particle-size atomized spherical aluminum powder: particle size 1-2μm, purity ≥99.75%, purchased from Hunan Jinhao New Material Technology Co., Ltd.

[0030] Medium-sized atomized spherical aluminum powder: particle size 4-5μm, purity ≥99.75%, purchased from Hunan Jinhao New Material Technology Co., Ltd.

[0031] High-particle-size atomized spherical aluminum powder: particle size 9-11μm, purity ≥99.8%, purchased from Hunan Jinhao New Material Technology Co., Ltd.

[0032] Silane coupling agent: 3-aminopropyltriethoxysilane, KH-550, purchased from Shanghai Maclean;

[0033] Octamethylcyclotetrasiloxane: Zhejiang Hengyecheng Organosilicon Co., Ltd.;

[0034] 1,3,5-Trimethyl-1,3,5-tris(3,3,3,-trifluoropropyl)cyclotrisiloxane: 99%, Xifu Technology Co., Ltd.;

[0035] 2,4,6,8-Tetramethylcyclotetrasiloxane: 97%, Hubei Changfu Chemical Co., Ltd.;

[0036] Tetramethyltetravinylcyclotetrasiloxane: 95%, Nanjing Silicon Innovation Materials Co., Ltd.;

[0037] 1,1,3,3-Tetramethyldisiloxane: 95%, Zhuangming New Materials Technology Jiangsu Co., Ltd.;

[0038] 1-Vinyladamantane: 99% purity, Tianjin Nuokang Pharmaceutical Technology Co., Ltd.;

[0039] 2,4,6,8-Tetra(β-adamantaneethyl)tetramethylcyclotetrasiloxane: In-house prepared according to the following method:

[0040] 0.1 mol of 2,4,6,8-tetramethylcyclotetrasiloxane was pre-dried using molecular sieves, and 0.4 mol of 1-vinyladamantane was purified by recrystallization from ethanol before use. 1 mol of 2,4,6,8-tetramethylcyclotetrasiloxane and 50 ml of anhydrous toluene were added to a reaction vessel, and the mixture was purged with nitrogen for 15 min to remove oxygen. Under a nitrogen atmosphere, 0.4 mol of 1-vinyladamantane was slowly added and stirred until homogeneous. The reaction system was placed in an ice bath at 0–5 °C. 90 μL of Karstedt catalyst (2% (wt) xylene solution) was injected into the system using a syringe. The mixture was stirred until homogeneous and kept at this temperature for 30 min. The ice bath was removed, and the temperature was programmed to rise to 60 °C and held for 1 hour, then at 80 °C for 2 hours. 0.1 g of activated carbon was added and stirred for 30 min to adsorb Pt. The mixture was then filtered. The solvent was removed by vacuum distillation at 60 °C to obtain 2,4,6,8-tetra(β-adamantaneethyl)tetramethylcyclotetrasiloxane, with a yield of 96%. 1 H-NMR (CDCl3, 400MHz) Figure 3 As shown, the successful synthesis of 2,4,6,8-tetra(β-adamantaneethyl)tetramethylcyclotetrasiloxane is demonstrated.

[0041] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0042] Preparation Example

[0043] Spherical aluminum nitride: self-made, preparation method as follows:

[0044] Low-particle-size, medium-particle-size, and high-particle-size atomized spherical aluminum powders were mixed according to the weight proportions in Table 1 and evenly spread in a quartz crucible with a thickness controlled at 2–4 mm. Nitrogen gas was introduced into a tube furnace at a flow rate of 3 L / min. After 30 minutes of gas introduction, aluminum powder was added and heated to 1100°C at a heating rate of 5°C / min. The temperature was held for 90 minutes, and then cooled to 60°C at a cooling rate of 10°C / min. The quartz crucible was then removed to obtain spherical aluminum nitride.

[0045] The degree of nitriding is calculated based on the weight of aluminum powder and aluminum nitride before and after the reaction. The formula is: Degree of nitriding (%) = (Actual weight gain / Theoretical weight gain 51.8%) × 100%.

[0046] Table 1. Raw materials, nitriding temperature, and degree of nitriding for spherical aluminum nitride.

[0047]

[0048]

[0049] As shown in Table 1, smaller particle sizes of aluminum powder result in higher nitriding degrees. This is because smaller particle sizes have a larger specific surface area, providing more nitriding reaction sites, and the higher bed porosity facilitates nitrogen diffusion, making the nitriding reaction easier. Conversely, larger particle sizes of aluminum powder have a smaller specific surface area and lower porosity, and the large amount of molten aluminum generated during the reaction clogs the pores, hindering nitrogen diffusion and resulting in lower nitriding degrees. When aluminum powders of different particle sizes are blended in a certain proportion, the smaller particle sizes in the blend can reduce the content of molten aluminum in the system, reduce the clogging of pores by the molten aluminum generated by the larger particle sizes, maintain unobstructed nitrogen diffusion channels, promote the nitriding reaction, and thus improve the nitriding degree.

[0050] Although large-particle-size aluminum powder has a low degree of nitridation, its interfacial thermal resistance in silicone oil is lower, resulting in better thermal conductivity. However, large-particle-size thermally conductive fillers are difficult to pack tightly, which is detrimental to the formation of thermal conductive pathways. When used in combination with spherical aluminum nitride of different particle sizes, the smaller-particle-size filler can fill the gaps between the larger-particle-size fillers, creating a more complete thermal conductive pathway. At the same time, the spherical structure of the aluminum nitride allows it to maintain high fluidity even with a large filling amount of thermally conductive filler.

[0051] Modified silicone oil: self-made, preparation method is as follows:

[0052] S1. Dissolve octamethylcyclotetrasiloxane, 2,4,6,8-tetra(β-adamantaneethyl)tetramethylcyclotetrasiloxane, 1,3,5-trimethyl-1,3,5-tris(3,3,3,-trifluoropropyl)cyclotrisiloxane monomers and a portion of 1,1,3,3-tetramethyldisiloxane in toluene according to the proportions shown in Table 2. Purge with nitrogen for 20 min. Prepare a 0.5 mol / L anhydrous toluene solution of tetramethylammonium hydroxide silanolate. Under a nitrogen atmosphere, add 0.2 mol% tetramethylammonium hydroxide silanolate solution (equivalent to the molar amount of the monomers) dropwise to the reaction system at room temperature. Keep the temperature at 30 °C for 30 min, then increase the temperature to 80 °C at a rate of 1 °C / min and maintain the temperature for 2 h. The temperature was lowered to 60℃, and the remaining end-capping agent, 1,1,3,3-tetramethyldisiloxane, was added. Stirring was continued at 60℃ for 1 hour. The temperature was then raised to 135℃ and maintained for 30 minutes to decompose tetramethylammonium hydroxide silanolate. Low-boiling-point substances were removed under vacuum at 80℃. After cooling, the mixture was filtered through a 0.2 μm PTFE membrane to obtain a colorless, viscous liquid, which was the linear silicone oil. The molecular weight was determined by GPC, and the results are shown in Table 2.

[0053] S2. Linear silicone oil, anhydrous toluene, and tetramethyltetravinylcyclotetrasiloxane were pre-dried using molecular sieves. 100g of linear silicone oil and 100ml of anhydrous toluene were weighed and added to a reaction vessel. The vessel was purged with nitrogen for 15min to remove oxygen. Tetramethyltetravinylcyclotetrasiloxane and 60mg of ethynylcyclohexanol (used as an inhibitor) as shown in Table 3 were added and pre-dissolved in 5mL of toluene. Under a nitrogen atmosphere, the mixture was added to the linear silicone oil system and stirred at 25℃ for 5min until completely dissolved. The reaction system was then placed in an ice bath at 0-5℃. Under these conditions, 56 μL of Karstedt catalyst in a 2% (wt) xylene solution was injected into a syringe. The mixture was stirred thoroughly and kept at this temperature for 30 min. The ice bath was removed, and the temperature was programmed to rise to 35°C and held for 2 hours, followed by holding at 55°C for 1 hour. 20 μL of triethylamine was added to neutralize free HCl and coordinate Pt. Stirring was continued at 55°C for 10 min. Toluene was removed by rotary evaporation under reduced pressure at 55°C and -0.09 MPa, yielding a colorless, transparent, viscous oil. The product was a mixture of star-shaped and linear silicone oils. A schematic diagram of the reaction process is shown below. Figure 2 As shown. Infrared spectroscopy tests were performed on linear silicone oil 1, linear silicone oil 8, and modified silicone oil 1 (Fourier transform infrared spectrometer: Nicolet FTIR-AvATAR360, 4000~500cm). -1 The result is as follows Figure 4 As shown, from Figure 4 It can be seen that linear silicone oil 1, compared to linear silicone oil 8, has a lower viscosity at 2905 cm⁻¹. -1 The characteristic peak of adamantane bridgehead tertiary CH appeared at 1250 cm⁻¹. -1 and 1100cm -1 The presence of characteristic peaks containing fluorinated alkyl groups at 2200 cm⁻¹ confirms the successful polymerization of the linear silicone oil; the infrared spectrum of modified silicone oil 1, compared to linear silicone oil 1, shows a peak at 2200 cm⁻¹. -1 The peak intensity of Si-H decreased, and the 1640–1645 cm⁻¹ range was not detected. -1 The presence of a peak related to C=C indicates that the alkenyl group in tetramethyltetravinylcyclotetrasiloxane has been completely consumed or is too weak to be detected, thus confirming the successful synthesis of star-shaped silicone oil.

[0054] Table 2. Raw materials and proportions (molar parts) of linear silicone oil

[0055] Table 3. Mass fraction of modified silicone oil

[0056]

[0057] Examples and Comparative Examples

[0058] A spherical aluminum nitride silicone grease high thermal conductivity interface material composition is prepared by the following method:

[0059] (1) Weigh 1% of the total mass of spherical aluminum nitride with aminosilane coupling agent, and weigh appropriate amounts of ethanol and water in a mass ratio of ethanol:water:silane coupling agent = 7:1:2; mix the silane coupling agent, ethanol and water, stir evenly, and perform hydrolysis treatment at room temperature for 25 min to obtain a diluted silane coupling agent solution; add spherical aluminum nitride to the mixer, and preheat the mixer temperature to 130℃ for a period of time, then add the diluted silane coupling agent solution dropwise to the spherical aluminum nitride in 3 portions, and stir for 10 min; cool, filter to obtain spherical aluminum nitride, put it in an oven, and dry it at a constant temperature of 120℃ for 3 h to obtain surface-treated spherical aluminum nitride.

[0060] (2) Add 15 parts of modified silicone oil to the mixer, and then add 85 parts of surface-treated spherical aluminum nitride to the modified silicone oil. The serial numbers of the modified silicone oil and spherical aluminum nitride are shown in Table 4. The spherical aluminum nitride and modified silicone oil are stirred and mixed in the mixer. Then, the mixer is vacuumed twice in vacuum mode. The material is discharged to obtain a high thermal conductivity interface material composition of spherical aluminum nitride silicone grease.

[0061] Table 4 Formulation of spherical aluminum nitride and modified silicone oil

[0062]

[0063]

[0064] The spherical aluminum nitride silicone grease high thermal conductivity interface materials prepared in the examples and comparative examples were subjected to the following performance tests, and the results are shown in Table 5.

[0065] 1. Thermal conductivity: The thermal conductivity of the spherical aluminum nitride silicone grease high thermal conductivity interface material compositions of the examples and comparative examples was tested using a thermal conductivity meter to analyze their thermal conductivity. The testing reference standard was ISO 22007-2-2008.

[0066] 2. Viscosity test: The spherical aluminum nitride silicone grease high thermal conductivity interface material compositions of the examples and comparative examples were tested using a viscometer to analyze their viscosity. The test reference standard was ASTM D4287-2023.

[0067] 3. Thermal shock test: The thermal conductivity retention rate of the spherical aluminum nitride silicone grease high thermal conductivity interface material compositions of the test examples and comparative examples was measured after 1000 cycles at -40 to 85°C (each cycle is 0.5h).

[0068] 4. Migration performance test: The spherical aluminum nitride silicone grease high thermal conductivity interface material compositions prepared in the examples and comparative examples were coated on test pieces sprayed with aerospace thermal control coating for migration performance test. The coating diameter was 30 mm and the thickness was 1 mm. The test pieces coated with the spherical aluminum nitride silicone grease high thermal conductivity interface material compositions were placed at 85°C for 96 h to test whether migration occurred.

[0069] Table 5 Performance test results of the examples and comparative examples

[0070]

[0071] As can be seen from the examples and comparative examples, the spherical aluminum nitride silicone grease high thermal conductivity interface material composition prepared by the present invention has the advantages of high thermal conductivity, moderate viscosity, low migration rate, and high heat resistance, meeting the performance requirements of thermal grease for electronic devices, especially aerospace devices. Comparative Examples 1 and 2 show that the molecular weight of the modified silicone oil, whether too large or too small, has a significant impact on viscosity. When the viscosity is too high, the spherical aluminum nitride is unevenly dispersed, resulting in poor flowability of the thermal grease and an inability to effectively fill pores. When the viscosity is too low, the high temperature of electronic components easily leads to evaporation and migration of the silicone oil, causing the thermal grease to dry and harden, thus losing its thermal conductivity. Comparative Examples 3 and 4, respectively, do not introduce adamantane molecules and fluorinated alkyl molecules, which significantly affects heat resistance and migration performance. The silicone oil in Comparative Example 6 contains only low molecular weight linear silicone oil, which is prone to migration or evaporation.

[0072] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A spherical aluminum silicon nitride grease high thermal conductive interface material composition, characterized in that, By weight parts, including spherical aluminum nitride 50~85 parts, modified silicone oil 15~50 parts, the modified silicone oil is methyl silicone oil with adamantane molecules and fluorine-containing alkyl groups grafted on the side chain of silicone oil, the modified silicone oil includes 60~80% of star-shaped silicone oil and 20~40% of linear silicone oil, the number average molecular weight of the star-shaped silicone oil is 15000~40000g / mol, and the number average molecular weight of the linear silicone oil is 5000~8000g / mol; the spherical aluminum nitride is a compound of low particle size spherical aluminum nitride, medium particle size spherical aluminum nitride and high particle size spherical aluminum nitride, the particle size of the low particle size spherical aluminum nitride is 1~2μm; the particle size of the medium particle size spherical aluminum nitride is 4~6μm; the particle size of the high particle size spherical aluminum nitride is 9~11μm; the spherical aluminum nitride is also surface treated by amino silane coupling agent; the preparation method of the modified silicone oil is: S1. Dissolve methylcyclosiloxane, 2,4,6,8-tetra(β-adamantane ethyl) tetramethylcyclotetrasiloxane, 1,3,5-trimethyl-1,3,5-tri(3,3,3-trifluoropropyl)cyclotrisiloxane monomer and part of the end-capping agent in toluene, remove oxygen in the system by nitrogen blowing, prepare a catalyst solution, maintain a nitrogen atmosphere, add the catalyst solution dropwise into the reaction system at room temperature, first incubate and stir at 25~30℃, then heat to 70~90℃, and maintain for 2~4h; finally, cool to 50~70℃, add the remaining end-capping agent, and continue to stir for 1h; remove the catalyst and solvent, filter, and obtain linear silicone oil; the catalyst is selected from one or both of tetramethylammonium hydroxide silanol and tetraethylammonium hydroxide silanol; the end-capping agent is tetramethyldisiloxane; S2. Dry linear silicone oil, anhydrous toluene and tetramethyltetraethenylcyclotetrasiloxane by molecular sieve pretreatment, add linear silicone oil and anhydrous toluene to a reaction container, remove oxygen by nitrogen blowing, add tetramethyltetraethenylcyclotetrasiloxane and ethynylcyclohexanol corresponding to 15~20% molar parts of linear silicone oil under a nitrogen atmosphere, stir at room temperature until completely dissolved, place the reaction system in an ice bath at 0~5℃, inject Karstedt catalyst, stir uniformly, incubate for a period of time, remove the ice bath, program to heat to 30~40℃ for 1~3h, then 50~60℃ for 0.5~2h, purify after the reaction is completed to obtain a mixture of star-shaped silicone oil and linear silicone oil, which is the modified silicone oil.

2. The spherical aluminum silicon nitride grease high thermal conductive interface material composition of claim 1, wherein, The spherical aluminum nitride is prepared by heating low particle size atomized spherical aluminum powder, medium particle size atomized spherical aluminum powder and high particle size atomized spherical aluminum powder to 1000~1300℃ at a heating rate of 5~10℃ / min under the condition of continuous nitrogen blowing for 60~120min.

3. The spherical aluminum silicon nitride grease high thermal conductive interface material composition of claim 1, wherein, The methylcyclosiloxane is selected from one or more of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane.

4. The spherical aluminum silicon nitride grease high thermal conductive interface material composition of claim 1, wherein, The preparation method of 2,4,6,8-tetra(beta-adamantane ethyl) tetramethyl cyclotetrasiloxane is as follows: 2,4,6,8-tetramethyl cyclotetrasiloxane and 1-vinyl adamantane are pre-dried and purified, 2,4,6,8-tetramethyl cyclotetrasiloxane and anhydrous toluene are added to a reaction container under strict anhydrous and anaerobic conditions, oxygen is removed by nitrogen blowing, 1-vinyl adamantane is slowly added under a nitrogen atmosphere, the reaction system is stirred uniformly, the reaction system is placed in an ice bath at 0-5 DEG C, Karstedt catalyst is injected, stirring is performed for a period of time, the ice bath is removed, the temperature is gradually increased to 60-80 DEG C, and the system is kept for 1-3 hours, the catalyst is removed, and filtration is performed; the solvent is removed by distillation under reduced pressure, and 2,4,6,8-tetra(beta-adamantane ethyl) tetramethyl cyclotetrasiloxane is obtained.

5. The method of producing a spherical aluminum nitride silicon grease high thermal conductive interface material composition according to any one of claims 1 to 4, characterized by, The method comprises the following steps: (1) surface treatment of spheroidized aluminum nitride using a silane coupling agent; (2) adding the spheroidized aluminum nitride treated with the silane coupling agent into modified silicone oil, stirring and mixing in a mixer, discharging after vacuumizing, and obtaining a high-thermal-conductivity interface material composition of spheroidized aluminum nitride silicone grease.

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