Liquid metal-based thermal conductive silicone grease, preparation method and application thereof

Abstract

This invention provides a liquid metal-based thermal grease, its preparation method, and its application. The liquid metal-based thermal grease comprises the following raw materials in parts by weight: 100 parts liquid metal, 2-5 parts silicone oil, 0.1-20 parts thermally conductive powder filler, and 0.1-3 parts other additives. The high-reliability liquid metal-based thermal grease provided by this invention possesses excellent high thermal conductivity, high processability, and high reliability. It can replace traditional thermal grease to solve the heat dissipation and cooling problem of high-power chips, thereby extending the lifespan of electronic products.

Description

Technical Field

[0001] This invention belongs to the field of thermal conductive materials technology, specifically relating to a liquid metal-based thermal conductive grease, its preparation method, and its application. Background Technology

[0002] With the rapidly increasing heat dissipation requirements of electronic products, the demand for thermal interface materials with high heat dissipation capabilities is also constantly rising. Thermal grease, as one of the important types of thermal interface materials, has advantages such as good heat dissipation, ease of use, and high production efficiency. Traditional thermal greases typically use metallic alumina such as alumina and zinc oxide, as well as metal particles such as aluminum powder and silver powder as thermal fillers. Under the premise of meeting good application processability and long-term reliability requirements, its ultimate thermal conductivity usually does not exceed 6 W / m·K, and its minimum thermal resistance can reach approximately 0.04 K·cm. 2 / W, which makes it difficult to meet the requirement of heat flux density exceeding 1000W / cm². 2 The chip's heat dissipation requirements.

[0003] Liquid metals such as elemental gallium and gallium alloys (gallium-indium alloy, gallium-indium-tin alloy, gallium-indium-tin-zinc alloy, etc.) are non-toxic, harmless, have low melting points, and high thermal conductivity. Furthermore, the melting point can be adjusted by controlling the proportions of each element. Currently, there are a few cases of using Galinstan (e.g., 68.5% gallium, 21.5% indium, and 10% tin) to replace traditional thermal grease for heat dissipation. Its thermal conductivity is approximately 27 W / m·K, its melting point is as low as -19°C, and its boiling point exceeds 1300°C, exhibiting good processability and excellent heat dissipation performance.

[0004] However, liquid metal materials have yet to replace traditional thermal grease in mass production. Besides cost, this is mainly due to the following serious risks that may arise during practical use. First, there's the insulation issue. Liquid metals have excellent electrical conductivity, limiting their application to heat dissipation scenarios where insulation is not required. Second, there's the corrosion issue. Gallium and its alloys have a significant corrosive effect on common metal substrates such as copper and aluminum. Gallium atom migration can lead to the dissolution and embrittlement of the metal substrate, restricting its primary applications. Furthermore, due to their low viscosity and high fluidity, liquid metals still pose a significant risk of leakage, even with some protective structural design. Leakage can cause short circuits and device corrosion, posing a fatal risk to the use of electronic devices. Summary of the Invention

[0005] In view of this, the present invention provides a liquid metal-based thermal grease, its preparation method and application, which has excellent high thermal conductivity, high processability and high reliability. It can replace traditional thermal grease to solve the heat dissipation and cooling problem of high power consumption chips and improve the service life of electronic products.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a liquid metal-based thermal grease, comprising the following raw materials in parts by weight: 100 parts liquid metal, 2-5 parts organosilicon oil, 0.1-20 parts thermally conductive powder filler, and 0.1-3 parts other additives.

[0007] Preferably, the liquid metal comprises elemental gallium or an alloy formed of gallium with at least one of indium, tin, zinc, and bismuth. It should be noted that the elemental gallium is metallic gallium with a purity of 4N or higher. In some embodiments, the gallium alloy is a commercially available Galinstan alloy with a melting point of -19°C and a composition of 68.5% gallium, 21.5% indium, and 10% tin, or other gallium, indium, tin, zinc, and bismuth alloys with a melting point not exceeding 40°C.

[0008] Preferably, the silicone oil comprises at least one of dimethyl silicone oil, diethyl silicone oil, methylphenyl silicone oil, vinyl silicone oil, hydrogen-containing silicone oil, or other modified silicone oils with different structures. It should be noted that the viscosity range of the dimethyl silicone oil and diethyl silicone oil at 25°C is 10-1000 cSt. The viscosity range of the methylphenyl silicone oil at 25°C is 10-1000 cSt, and the phenyl content is 1-40% mol%. The viscosity range of the vinyl silicone oil at 25°C is 10-1000 cSt, and the vinyl content is 0.1-2 mmol / g. The hydrogen-containing silicone oil is a single-ended, double-ended, or side-ended hydrogen-containing silicone oil, with a viscosity range of 5-200 cSt at 25°C and a hydrogen content of 0.2-2 mmol / g. The modified silicone oils mentioned above are trimethoxysiloxane or triethoxysiloxane-terminated dimethyl silicone oils, or epoxy-modified silicone oils, amino-modified silicone oils, etc., with a viscosity range of 20-2000 cSt at 25°C.

[0009] Preferably, the thermally conductive powder filler includes at least one or more of the following: alumina, aluminum nitride, silicon nitride, boron nitride, silicon carbide, magnesium oxide, zinc oxide, diamond, aluminum powder, copper powder, and silver powder.

[0010] Preferably, the thermally conductive powder filler has a spherical or near-spherical morphology, a median particle size of 0.1-10 μm, and a maximum particle size of no more than 20 μm.

[0011] Preferably, the other additives include one or more of the following: desiccant, thixotropic agent, catalyst, inhibitor, diluent, thickener, antioxidant, surfactant, and pigment.

[0012] Preferably, the desiccant includes 3A molecular sieve, 4A molecular sieve, isocyanate or silane coupling agent that readily reacts with water; it should be noted that 3A and 4A molecular sieves are physical adsorption desiccants, and isocyanate or silane coupling agents that readily react with water are chemical dehydrating agents, and / or, The thixotropic agent comprises fumed silica, carbon black, calcium carbonate, or zinc oxide with a particle size of 10-200 nm; and / or, The catalyst comprises any one of platinum-vinylsiloxane, platinum-alkynyl chelate, chloroplatinic acid, or microencapsulated platinum catalyst; and / or The inhibitors include polyvinyl alcohol inhibitors or ethynyl alcohol inhibitors; and / or, The diluent includes small molecule alkanes, unsaturated hydrocarbons, organosilicon cyclic compounds, or low-viscosity dimethyl silicone oil; it should be noted that the diluent can reduce the viscosity of the system, and / or, The pigments include cobalt blue, iron oxide red, carbon black, or cadmium yellow. It should be noted that in some embodiments, the pigments include cobalt blue, iron oxide red, carbon black, cadmium yellow, or other colored powders; in other embodiments, these powders can be dispersed in silicone oil to form a color paste.

[0013] Secondly, the present invention provides a method for preparing the liquid metal-based thermal grease, comprising the following steps: S1. After melting the liquid metal, mix it with silicone oil and stir under vacuum to obtain droplets coated with silicone oil. S2. Mix the silicone oil-coated droplets, thermally conductive powder filler, and other additives, and stir to obtain liquid metal-based thermally conductive silicone grease.

[0014] In some embodiments, the operation method is as follows: Step 1: Heat and melt the liquid metal, weigh it together with the silicone oil according to the specified ratio, add it all at once to a mixing device, and stir under vacuum to break the liquid metal into small droplets coated with silicone oil for later use. The stirring speed is 500-3000 rpm, the rotation-to-revolution ratio is 1-90%, and the stirring time is 0.5-20 min.

[0015] It should be noted that the above-mentioned mixing equipment is a non-invasive homogenizer with a PE, PP, PTFE or other plastic tank, and the tank volume is 0.1-20L. The rotation-to-revolution ratio of the above-mentioned stirring process is 5-70%, and the stirring time is 0.5-10 minutes. After the above-mentioned stirring is completed, the size of the liquid metal droplets coated with silicone oil is no more than 30μm.

[0016] Step 2: Weigh the thermally conductive powder filler and other remaining additives according to the specified ratio, add them to the above-mentioned mixing equipment, and stir evenly under vacuum. The stirring speed is 200-1000 rpm, the rotation-to-revolution ratio is 1-90%, and the stirring time is 0.5-20 min.

[0017] It should be noted that the rotation-to-revolution ratio during the above stirring process is 5-70%, and the stirring time is 0.5-5 minutes.

[0018] Step 3: Discharge and dispense the material into single-component tubing or other packaging materials, vacuum degas, and then seal and store at room temperature or low temperature.

[0019] Preferably, in step S1, the stirring rate is 500-3000 rpm, the rotation-to-revolution ratio is 1-90%, and the stirring time is 0.5-20 min; and / or, In step S2, the stirring rate is 200-1000 rpm, the rotation-to-revolution ratio is 1-90%, and the stirring time is 0.5-20 min; and / or, In step S2, after obtaining the liquid metal-based thermal grease, it is discharged and packaged into single-component tubing or other packaging materials, vacuum degassing, and then sealed and stored at room temperature or low temperature.

[0020] Thirdly, the present invention provides the application of the liquid metal-based thermal grease described above, or the liquid metal-based thermal grease prepared by the preparation method described above, in the preparation of thermal conductive materials for electronic products.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention utilizes a blend of liquid metal, silicone oil, thermally conductive powder filler, and other additives to obtain a highly reliable liquid metal-based thermal grease. This liquid metal-based thermal grease simultaneously possesses a high thermal conductivity exceeding 6.0 W / m·K and a thermal conductivity of 0.01 K·cm⁻¹. 2It boasts ultra-low thermal resistance below / W and excellent application processability. Compared to pure liquid metal systems, the liquid metal-based thermal grease of this invention exhibits a volume resistivity exceeding 10^10 Ω·cm, effectively meeting the requirements for insulation applications. Furthermore, it does not exhibit miscibility or corrosion with common substrates such as aluminum, copper, nickel, and stainless steel. Moreover, unlike other liquid metal thermal grease formulations, the desiccant used in this invention significantly mitigates oxidation and hydrolysis issues of liquid metal droplets in high-temperature and high-humidity environments, while the thixotropic agent significantly reduces the risk of slippage and silicone oil precipitation during long-term use. Furthermore, unlike other methods for preparing liquid metal thermal greases, the method of this invention disperses the liquid metal into smaller droplets. These smaller droplets have lower thermal resistance and better encapsulation, and are less likely to break and fuse into larger droplets under external forces. Therefore, the prepared liquid metal-based thermal grease has significantly improved scratch resistance, preventing liquid metal leakage under repeated friction and shearing, and greatly reducing the risk of liquid metal spillage during product use. In summary, the high-reliability liquid metal-based thermal grease provided by this invention possesses excellent high thermal conductivity, high processability, and high reliability, and can replace traditional thermal greases to solve the heat dissipation and cooling problems of high-power chips, thereby extending the lifespan of electronic products. Attached Figure Description

[0022] Figure 1 This is an optical microscope image of the liquid metal-based thermal grease provided in Embodiment 1 of the present invention at 1000x magnification. Figure 2 This is an optical microscope image of the liquid metal-based thermal grease provided in Embodiment 6 of the present invention at 1000x magnification. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention.

[0024] Example 1 This embodiment provides a liquid metal-based thermal grease, which comprises, by weight: 100 parts liquid metal, 3.6 parts silicone oil, 6 parts thermally conductive powder filler, and 1 part other additives.

[0025] The liquid metal is 4N elemental gallium. The silicone oil is a polydimethylsiloxane with a degree of polymerization of 100, terminally capped with trimethoxysiloxane. The thermally conductive powder filler is a mixture of powders of different types and particle sizes in a specific ratio, including 1 part of spherical alumina with a median particle size of 5 μm and 5 parts of zinc oxide with a median particle size of 0.1 μm. The other additives are 3A molecular sieve activated powder with a particle size of 2-5 μm and a static water adsorption capacity ≥25 wt%.

[0026] This embodiment also provides a method for preparing the above-mentioned liquid metal-based thermal grease, including the following steps: Step 1: Seal and heat the liquid metal at 40°C for 2 hours until completely melted. Weigh the liquid metal and silicone oil according to the specified ratio, add them to the plastic mixing tank of a non-invasive homogenizer, and disperse the liquid metal into silicone oil-coated droplets according to the following process parameters: Stage 1-1: Rotation speed 800 rpm, rotation-to-revolution ratio 70%, vacuum degree 50%, time 10s; Stage 1-2: Rotation speed 1500 rpm, rotation-to-revolution ratio 40%, vacuum degree 70%, time 30s; Stages 1-3: Rotation speed 2500 rpm, rotation-to-revolution ratio 25%, vacuum degree 100%, time 120s.

[0027] Step 2: Weigh the thermally conductive powder filler and other remaining additives according to the specified ratio, add them to the plastic mixing tank of a non-invasive homogenizer, and disperse them according to the following process parameters to prepare liquid metal-based thermally conductive silicone grease: Stage 2-1: Rotation speed 300 rpm, rotation-to-revolution ratio 70%, vacuum degree 50%, time 10s; Stage 2-2: Rotation speed 500 rpm, rotation-to-revolution ratio 40%, vacuum degree 70%, time 30s; Stage 2-3: Rotation speed 1000 rpm, rotation-to-revolution ratio 30%, vacuum degree 100%, time 90s.

[0028] Step 3: Dispense the prepared liquid metal-based thermal grease into single-component tubing or other packaging materials. After vacuum degassing, seal and store at room temperature or low temperature. The prepared product is shown in the optical microscope image at 1000x magnification. Figure 1 As shown.

[0029] Example 2 This embodiment provides a liquid metal-based thermal grease and its preparation method. Unlike Embodiment 1, the liquid metal used is a commercially available Galinstan alloy with a ratio of 68.5% gallium, 21.5% indium, and 10% tin. It is liquid at room temperature, so there is no need to heat and melt it in step one.

[0030] Example 3 This embodiment provides a liquid metal-based thermal grease, which comprises, by weight: 100 parts liquid metal, 3.6 parts silicone oil, 12 parts thermally conductive powder filler, and 0.5 parts other additives.

[0031] The liquid metal is 4N elemental gallium. The silicone oil is a polydimethylsiloxane with a degree of polymerization of 30, terminally capped with trimethoxysiloxane. The thermally conductive powder filler is a mixture of powders of different types and particle sizes in a specific ratio, including 10 parts of spherical aluminum nitride with a median particle size of 5 μm and 2 parts of zinc oxide with a median particle size of 0.1 μm. The other additives are 3A molecular sieve activated powder with a particle size of 2-5 μm and a static water adsorption capacity ≥25 wt%.

[0032] In this embodiment, the liquid metal-based thermal grease is prepared using the same method as in Example 1.

[0033] Example 4 This embodiment provides a liquid metal-based thermal grease and its preparation method. The difference from Embodiment 3 is that the thermally conductive powder filler is 7 parts.

[0034] The aforementioned thermally conductive powder filler is a compound of powders of different types and particle sizes in a certain proportion, including 5 parts of diamond micro powder with a median particle size of 3μm and 2 parts of zinc oxide with a median particle size of 0.1μm.

[0035] Example 5 This embodiment provides a liquid metal-based thermal grease and its preparation method. The difference from Embodiment 3 is that the thermally conductive powder filler is 12 parts.

[0036] The aforementioned thermally conductive powder filler is a compound of powders of different types and particle sizes in proportion, including 7 parts of spherical aluminum powder with a median particle size of 5μm, 3 parts of spherical aluminum powder with a median particle size of 1μm, and 2 parts of zinc oxide with a median particle size of 0.1μm.

[0037] Example 6 This embodiment provides a liquid metal-based thermal grease and its preparation method. The difference from Embodiment 3 is that the thermally conductive powder filler is 20 parts.

[0038] The aforementioned thermally conductive powder filler is a blend of powders of different types and particle sizes in a specific ratio, including 15 parts of spherical silver powder with a median particle size of 3 μm and 5 parts of spherical silver powder with a median particle size of 0.8 μm. The optical microscope image of the prepared product at 1000x magnification is shown below. Figure 2 As shown.

[0039] Comparative Example 1 This comparative example provides a liquid metal-based thermal grease and its preparation method. Unlike Example 1, the thermally conductive powder filler is one part of spherical alumina with a median particle size of 5 μm.

[0040] Comparative Example 2 This comparative example provides a liquid metal-based thermal grease and its preparation method. Unlike Example 1, the formulation does not include 3A molecular sieve activating powder as an additive.

[0041] Comparative Example 3 This comparative example provides a liquid metal-based thermal grease and its preparation method. Unlike Example 1, step one of the preparation method involves dispersing the liquid metal into droplets coated with silicone oil according to the following process parameters: Stage 1-1: Rotation speed 300 rpm, rotation-to-revolution ratio 70%, vacuum degree 50%, time 10s; Stage 1-2: Rotation speed 500 rpm, rotation-to-revolution ratio 40%, vacuum degree 70%, time 30s; Stages 1-3: Rotation speed 1000 rpm, rotation-to-revolution ratio 30%, vacuum degree 100%, time 90s.

[0042] Comparative Example 4 This comparative example provides a liquid metal-based thermal grease and its preparation method. Unlike Example 1, step two of the preparation method involves dispersing and preparing the liquid metal-based thermal grease according to the following process parameters: Stage 2-1: Rotation speed 800 rpm, rotation-to-revolution ratio 70%, vacuum degree 50%, time 10s; Stage 2-2: Rotation speed 1500 rpm, rotation-to-revolution ratio 40%, vacuum degree 70%, time 30s; Stage 2-3: Rotation speed 2500 rpm, rotation-to-revolution ratio 25%, vacuum degree 100%, time 120s.

[0043] Comparative Example 5 Comparative Example 5 is a commercially available thermal grease with a thermal conductivity of 6.0 W / m·K, which contains 65% spherical alumina, 20% aluminum nitride, 10% zinc oxide and 5% silicone oil.

[0044] Performance Tests and Results Table 1. Comparison of some performance characteristics between Examples 1-2 and Comparative Examples 1-4

[0045] The technical specifications shown in Table 1 are as follows: Thermal conductivity test adopted ASTM D5470 standard, and the testing equipment was a Taiwan Ruiling LW-9389 thermal resistance tester. The thermal resistance test was obtained by fitting the thermal resistance test values ​​at thicknesses of 0.5mm, 1.0mm, and 1.5mm, with a hot end temperature of 80℃; Thermal resistance test adopted ASTM D5470 standard, and the testing equipment was a Taiwan Ruiling LW-9389 thermal resistance tester. The hot end temperature was 80℃, and the test pressure was 40psi; Viscosity test adopted ASTM D2196 standard, and the testing equipment was a Bollefeld rotational viscometer. The viscosity at 10 rpm was tested using a CP14 rotor; Thixotropic index test adopted ASTM D2196 standard, and the testing equipment was a Bollefeld rotational viscometer. The viscosity ratio at 1 rpm and 10 rpm was tested using a CP14 rotor; Dispensing rate test was conducted using a 30cc EFD tube, and the dispensing amount was calculated after 5 seconds of testing at 0.2MPa air pressure; Volume resistivity test adopted ASTM D2196 standard. The resistance was calculated using the D257 standard, measured with a high-resistance meter at a 0.3mm electrode spacing and 10V. Scratch resistance testing was performed using an automatic printing machine with a hexagonal honeycomb structure and a thickness of 0.1mm. The printing speed was 50mm / s, and the squeegee was used for 10 repeated printing cycles. High-temperature aging conditions included 1000 hours of constant heating at 125℃; high-low temperature cycling aging conditions included 1000 cycles from -40℃ to 125℃, with each cycle consisting of 15 minutes of low-temperature constant temperature, 15 minutes of heating, 15 minutes of high-temperature constant temperature, and 15 minutes of cooling; high-temperature and high-humidity aging conditions included 1000 hours of heating at 85℃ and 85% RH. Appearance aging tests used a sandwich-structure appearance fixture with tempered glass on both sides, secured with 0.1mm thick steel rings, placed vertically in the aging chamber, and the appearance of the colloid before and after aging was observed for abnormalities such as pores, cracks, sagging, and metal droplet precipitation.

[0046] As can be seen from the test results of Example 1 in Table 1, the prepared liquid metal-based thermal grease has a high thermal conductivity of 6.3 W / m·K and a thermal conductivity of 0.009 K·cm⁻¹. 2 With an ultra-low thermal resistance of / W, it can meet the heat dissipation requirements of high-power chips. Meanwhile, the liquid metal-based thermal grease in this embodiment has low viscosity and appropriate thixotropy, exhibiting good processability regardless of whether it is applied by dispensing or printing, and does not exhibit abnormal phenomena such as cracking, sagging, slippage, or liquid metal precipitation during aging. Because the metal droplets are coated with silicone oil, this thermal grease also has a 9.1% thermal resistance. With a volume resistivity of 10^11 Ω·cm, and without corroding other metal substrates, it does not exhibit metal droplet breakage and precipitation even under high shear strength, demonstrating excellent reliability and significantly reducing the risks associated with using liquid metal. The liquid metal used in Example 2 is a commercially available Galinstan alloy with a melting point of -19°C, thus eliminating the need for heating during the manufacturing process. Except for a slight decrease in thermal conductivity due to Galinstan alloy's slightly lower thermal conductivity compared to pure gallium, its overall performance is quite similar to the liquid metal-based thermal grease in Example 1.

[0047] As can be seen from the test results of Comparative Example 1 in Table 1, the addition of nano-sized zinc oxide in Example 1 can improve the viscosity and thixotropy of the thermal grease without affecting its thermal conductivity. This helps to improve the problem of silicone oil precipitation during storage and use, and prevents the thermal grease from sliding downwards due to gravity when placed vertically. Gallium reacts with water vapor at high temperatures to generate gallium oxide and gallium hydroxide, releasing hydrogen gas. Therefore, under high temperature and high humidity aging conditions, the thermal grease is prone to porosity and cracking due to the release of hydrogen gas, thus affecting its thermal conductivity. As can be seen from the test results of Comparative Example 2, the 3A molecular sieve added in Example 1, through its extremely strong water absorption capacity and the coating of highly hydrophobic silicone oil, can prevent the reaction between water and gallium caused by liquid metal droplets under high temperature and high humidity conditions. As can be seen from the test results of Comparative Example 3, the droplet size of the liquid metal dispersed in the silicone oil during step one has a significant impact on the product performance. If the shear force used during dispersion is too small, the size of the liquid metal droplets will be larger. Although the prepared thermal grease has a lower viscosity and higher thermal conductivity, its thermal resistance is higher than that of Example 1 because the large droplets are relatively difficult to compress during use. More seriously, the scratch resistance of the large droplets will be significantly reduced, increasing the risk of leakage due to the breakage of the silicone oil-encapsulated liquid metal droplets during use. The test results of Comparative Example 4 show that, due to the addition of thermally conductive powder and other additives in step two, the viscosity of the thermal grease is significantly increased. If the shear force used during dispersion is too large, it will cause the well-dispersed liquid metal droplets in step one to break, resulting in product failure. In conclusion, the formulation design and precise control of the preparation process have a significant impact on the product performance of liquid metal-based thermal greases.

[0048] Table 2. Comparison of partial performance between Examples 3-6 and Comparative Example 5

[0049] As can be seen from the test results of Examples 3-6 in Table 2, adding fillers with higher thermal conductivity, such as aluminum nitride, diamond, aluminum powder, and silver powder, can further improve the thermal conductivity of the prepared liquid metal-based thermal grease to a high thermal conductivity of over 8.0 W / m·K. However, due to the poor sphericity and large specific surface area of ​​fine aluminum nitride and diamond powders, the viscosity of the thermal grease increases significantly after addition, leading to a decrease in processability and wettability at the substrate interface. Therefore, the thermal resistance of Examples 3-4 is not superior to that of Example 1. In contrast, spherical aluminum powder and spherical silver powder have better morphology and can be added in higher proportions without significantly affecting processability, thereby improving thermal conductivity. Furthermore, aluminum and silver have low hardness and are easily deformed and thinned under pressure, thus the prepared liquid metal-based thermal grease also shows a significant advantage in thermal resistance performance. Example 6 used a higher proportion of silver powder as an auxiliary thermally conductive filler, achieving a thermal conductivity of 10.2 W / m·K and a thermal resistance of only 0.007 K·cm. 2 / W, while also meeting reliability requirements during long-term use. In summary, compared to the commercially available conventional thermal grease in Comparative Example 5, the liquid metal-based thermal grease of this invention has a higher thermal conductivity, lower thermal resistance, and better processability, while also meeting insulation and reliability requirements. It can replace traditional thermal grease to meet the higher heat dissipation needs of chips and has broad application prospects.

[0050] Unless otherwise specified, all raw materials used in this invention are existing substances that can be purchased directly from the market.

[0051] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. 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 liquid metal-based thermal silicone grease, characterized in that, The raw materials include the following parts by weight: 100 parts liquid metal, 2-5 parts silicone oil, 0.1-20 parts thermally conductive powder filler, and 0.1-3 parts other additives.

2. The liquid metal-based thermal silicone grease of claim 1, wherein, The liquid metal includes elemental gallium or an alloy formed of gallium with at least one of indium, tin, zinc, and bismuth.

3. The liquid metal-based thermal grease according to claim 1, characterized in that, The silicone oil includes at least one of dimethyl silicone oil, diethyl silicone oil, methylphenyl silicone oil, vinyl silicone oil, hydrogen-containing silicone oil, or other modified silicone oils with different structures.

4. The liquid metal-based thermal grease according to claim 1, characterized in that, The thermally conductive powder filler includes at least one or more of the following: alumina, aluminum nitride, silicon nitride, boron nitride, silicon carbide, magnesium oxide, zinc oxide, diamond, aluminum powder, copper powder, and silver powder.

5. The liquid metal-based thermal grease according to claim 1, characterized in that, The thermally conductive powder filler has a spherical or near-spherical morphology, with a median particle size of 0.1-10 μm and a maximum particle size not exceeding 20 μm.

6. The liquid metal-based thermal grease according to claim 1, characterized in that, The other additives include one or more of the following: desiccants, thixotropic agents, catalysts, inhibitors, diluents, thickeners, antioxidants, surfactants, and pigments.

7. The liquid metal-based thermal grease according to claim 6, characterized in that, The desiccant includes 3A molecular sieve, 4A molecular sieve, isocyanate or silane coupling agent that readily reacts with water; and / or, The thixotropic agent comprises fumed silica, carbon black, calcium carbonate, or zinc oxide with a particle size of 10-200 nm; and / or, The catalyst comprises any one of platinum-vinylsiloxane, platinum-alkynyl chelate, chloroplatinic acid, or microencapsulated platinum catalyst; and / or The inhibitors include polyvinyl alcohol inhibitors or ethynyl alcohol inhibitors; and / or, The diluent includes small molecule alkanes, unsaturated hydrocarbons, organosilicon cyclic compounds, or low-viscosity dimethyl silicone oil; and / or, The pigments include cobalt blue, iron oxide red, carbon black, or cadmium yellow.

8. The method for preparing liquid metal-based thermal grease according to any one of claims 1-7, characterized in that, Includes the following steps: S1. After melting the liquid metal, mix it with silicone oil and stir under vacuum to obtain droplets coated with silicone oil. S2. Mix the silicone oil-coated droplets, thermally conductive powder filler, and other additives, and stir to obtain liquid metal-based thermally conductive silicone grease.

9. The preparation method according to claim 8, characterized in that, In step S1, the stirring rate is 500-3000 rpm, the rotation-to-revolution ratio is 1-90%, and the stirring time is 0.5-20 min; and / or, In step S2, the stirring rate is 200-1000 rpm, the rotation-to-revolution ratio is 1-90%, and the stirring time is 0.5-20 min; and / or, In step S2, after obtaining the liquid metal-based thermal grease, it is discharged and packaged into single-component tubing or other packaging materials, vacuum degassing, and then sealed and stored at room temperature or low temperature.

10. The application of the liquid metal-based thermal grease according to any one of claims 1-7, or the liquid metal-based thermal grease prepared by the preparation method according to claim 8 or 9, in the preparation of thermal conductive materials for electronic products.

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