Preparation method of graphene heat-conducting silicone grease

Abstract

The application relates to a preparation method of graphene heat-conducting silicone grease. Graphene slurry is prepared through a mechanical exfoliation method, a transfer solvent is added into the aqueous graphene slurry, and a dispersing agent, silicone oil and fillers are added into the transfer solvent to prepare the graphene heat-conducting silicone grease. The original sheet structure of graphene is maintained, and the graphene in the oil-based solvent can be more easily and uniformly dispersed in the silicone oil to form the silicone grease.

Description

Technical Field

[0001] This invention relates to the field of thermal conductive materials technology, and in particular to a method for preparing graphene thermal conductive grease. Background Technology

[0002] Thermal management has become one of the major challenges facing future electronic products. With the continuous increase in data generation and communication speeds, and the continuous reduction in the size and cost of industrial devices, the power density of electronic products is also constantly increasing, making the cooling of electronic circuits extremely challenging. There is an urgent need for thermally conductive materials with high thermal conductivity and good heat dissipation performance.

[0003] As a novel thermally conductive filler, graphene has been shown in experiments to have a thermal conductivity of up to 5300 W / (mK) for a single layer. It has advantages such as ultra-high carrier mobility, excellent thermal conductivity, high specific surface area and high flexibility. Therefore, by filling graphene into the thermally conductive silicone grease matrix, graphene-based thermally conductive materials with high thermal conductivity can be prepared. The thermal conductivity is far superior to that of interfacial thermally conductive materials prepared using other traditional fillers.

[0004] However, existing graphene thermal greases have a problem: the excellent thermal conductivity of graphene thermal greases is mainly due to the requirement that graphene powder maintains a complete planar structure and is dispersed as evenly as possible in the grease. However, existing graphene thermal grease preparation methods, whether chemical or mechanical exfoliation, produce graphene powder that exhibits phenomena such as "curling," "wrinkling," and "agglomeration" after drying, making it impossible to guarantee the original planar structure of graphene in the grease. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a method for preparing graphene thermal grease. Graphene slurry is prepared by mechanical exfoliation, and a transfer agent is used to directly transfer the aqueous sheet graphene into an oil-based solvent, maintaining the original sheet structure of the graphene. The graphene in the oil-based solvent will be more easily and uniformly dispersed in the silicone oil to form grease.

[0006] The technical solution adopted in this invention is:

[0007] A method for preparing graphene thermal grease, characterized by comprising the following steps:

[0008] S1. Graphite was added to ultrapure water and stirred evenly. Graphene slurry was obtained by mechanical exfoliation.

[0009] S2 filters the obtained graphene slurry, takes the filter cake, adds transfer solvent and stirs, washes the graphene slurry with transfer solvent, filters, and obtains a high-concentration graphene transfer solution.

[0010] S3 adds an oily dispersant to a high-concentration graphene transfer solution, stirs until homogenized by ultrasonication, and obtains a graphene suspension.

[0011] S4 adds the obtained oily graphene suspension and filler to silicone oil, and places it in a vacuum stirring vessel for continuous stirring for 2-24 hours to obtain a graphene thermal conductive silicone grease precursor.

[0012] S5 places the graphene thermal grease precursor in a constant temperature vacuum oven and heats it for 1-10 hours to obtain the graphene thermal grease.

[0013] This invention prepares graphene and fills it into a thermally conductive silicone grease matrix to create a graphene-based thermally conductive material with high thermal conductivity. To improve the dispersibility of graphene in the matrix, the invention first prepares graphene by exfoliation under aqueous conditions. This method yields good graphene exfoliation results, and smaller graphene particles can be obtained through mechanical exfoliation while maintaining the graphene sheet structure. Furthermore, a transfer solvent is used to treat the graphene slurry. On one hand, this treatment allows for better bonding between graphene and an oil-based dispersant; on the other hand, the transfer solvent can be used to wash the graphene slurry to obtain a high-concentration graphene transfer solution without introducing other solvents. The transfer solvent can also be reused to save costs. An oil-based dispersant is added to prepare a graphene suspension. This oil-based graphene suspension is then mixed with fillers to prepare graphene thermally conductive silicone grease. This ensures the dispersibility of graphene in the matrix, effectively solving the problems of graphene agglomeration and curling in the matrix, thereby improving the thermal conductivity of the graphene thermally conductive silicone grease.

[0014] Preferably, the mechanical peeling method in step S1 is at least one of ball milling, sand milling, and homogenization;

[0015] More preferably, the graphene particle size in the graphene slurry obtained in step S1 is 3-5 μm.

[0016] Preferably, the mass ratio of graphite to ultrapure water in step S1 is 1-5:99-95.

[0017] Preferably, the transfer solvent in step S2 includes one or more complexes of methanol, ethanol, isopropanol, n-butanol, isobutanol, ethylene glycol, and glycerol.

[0018] In a preferred embodiment, the transfer solvent in step S2 is a complex of methanol and ethylene glycol mixed in a 40:60 ratio.

[0019] Preferably, the mass concentration of graphene in the high-concentration graphene transfer solution in step S2 is 60-80%;

[0020] Preferably, the oily dispersant in step S3 includes one or more of the following compounds: zinc stearate, sodium stearate, oleic acid, Tween 80, and Span 80.

[0021] In a preferred embodiment, the oily dispersant in step S3 is a complex of zinc stearate and oleic acid mixed in a ratio of 12:88.

[0022] Preferably, the mass ratio of the oily dispersant in step S3 is 5-15%;

[0023] Preferably, the silicone oil in step S4 includes one or more complexes of dimethyl silicone oil, methyltrifluoropropyl silicone oil, vinyl silicone oil, and amino silicone oil.

[0024] In a preferred embodiment, the silicone oil in step S4 is a complex of methyl silicone oil and methyl trifluoropropyl silicone oil mixed in a ratio of 85:15.

[0025] Preferably, the filler in step S4 includes one or more of the following compounds: alumina, boron nitride, zinc oxide, and aluminum nitride.

[0026] In a preferred embodiment, the filler in step S4 is a complex formed by mixing alumina and zinc oxide in a ratio of 80:20.

[0027] Preferably, in step S4, the mass ratio of silicone oil is 5-20%, the mass ratio of filler is 70-90%, and the mass ratio of graphene suspension is 5-15%.

[0028] Preferably, the vacuum degree of the vacuum stirring vessel in step S4 is less than -0.08 MPa, and the rotation speed is 50-3000 rpm;

[0029] Preferably, the heating temperature of the constant temperature vacuum oven in step S5 is 80-180℃.

[0030] The beneficial effects of this invention are:

[0031] Graphene slurry was prepared by mechanical exfoliation. A solvent transfer method was used to better transfer the aqueous sheet graphene to an oil-based solvent. An oily dispersant was added to prepare a graphene suspension. This oily graphene suspension was then mixed with fillers to prepare graphene thermal grease. This process ensured that the graphene maintained its original sheet structure and did not agglomerate, thus guaranteeing its dispersibility in the matrix and effectively solving the problems of graphene agglomeration and curling in the matrix, thereby improving the thermal conductivity of the graphene thermal grease. Simultaneously, the addition of fillers in a specific ratio further reduced the volatile content of the thermal grease, enhancing the material's durability. Attached Figure Description

[0032] Figure 1 A photo of graphene thermal grease;

[0033] Figure 2 SEM image of graphene in the graphene thermal grease obtained in Example 1;

[0034] Figure 3 The image shows the SEM image of graphene in the graphene thermal grease obtained in Comparative Example 1. Detailed Implementation

[0035] The present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0036] Example 1:

[0037] (1) Graphite was added to ultrapure water and stirred evenly. After ball milling for 1 hour, sand milling for 4 hours, and homogenization for 3 hours, graphene slurry was obtained. The graphene particle size in the prepared graphene slurry was 3-5 μm. The mass ratio of graphite to ultrapure water was 5:95.

[0038] (2) Filter the obtained graphene slurry, take the filter cake, add the transfer solvent to the filter cake, stir thoroughly, wash the graphene slurry with the transfer solvent, and filter; repeat the above operation twice to obtain a high-concentration graphene transfer solution with a graphene mass concentration of 70%. The transfer solvent is a mixture of methanol and ethylene glycol in a ratio of 40:60.

[0039] (3) Add an oily dispersant to the high-concentration graphene transfer solution, stir evenly and then sonicate to obtain a graphene suspension.

[0040] The mass ratio of high-concentration graphene transfer solution to oily dispersant is 90:10; the oily dispersant is a mixture of zinc stearate and oleic acid in a ratio of 12:88.

[0041] (4) Add graphene suspension and filler to silicone oil, place it in a vacuum stirring vessel, set the vacuum degree to -0.08MPa, set the rotation speed to 2500rpm, and stir continuously for 18h. Obtain graphene thermal conductive silicone grease precursor.

[0042] The silicone oil is a mixture of methyl silicone oil and methyltrifluoropropyl silicone oil in a ratio of 85:15, and the filler is a mixture of alumina and zinc oxide in a ratio of 80:20. The mass ratio of the silicone oil, graphene suspension, and filler is 15%:5%:80%.

[0043] (5) Place the graphene thermal grease precursor in a constant temperature vacuum oven and heat it at 150°C for 7 hours to obtain the graphene thermal grease.

[0044] Example 2:

[0045] (1) Graphite was added to ultrapure water and stirred evenly. After ball milling for 1 hour, sand milling for 4 hours, and homogenization for 3 hours, graphene slurry was obtained. The graphene particle size in the prepared graphene slurry was 3-5 μm. The mass ratio of graphite to ultrapure water was 1:99.

[0046] (2) Filter the obtained graphene slurry, take the filter cake, add the transfer solvent to the filter cake, stir thoroughly, wash the graphene slurry with the transfer solvent, and filter; repeat the above operation twice to obtain a high-concentration graphene transfer solution. The mass concentration of graphene in the high-concentration graphene transfer solution is 60%. The transfer solvent is a mixture of methanol and ethylene glycol in a ratio of 40:60.

[0047] (3) Add an oily dispersant to the high-concentration graphene transfer solution, stir evenly and then sonicate to obtain a graphene suspension.

[0048] The mass ratio of high-concentration graphene transfer solution to oily dispersant is 80:20; the oily dispersant is a mixture of zinc stearate and oleic acid in a ratio of 12:88.

[0049] (4) Add graphene suspension and filler to silicone oil, place it in a vacuum stirring vessel, set the vacuum degree to less than -0.08 MPa, set the rotation speed to 500 rpm, and stir continuously for 2 hours. Obtain graphene thermal conductive silicone grease precursor.

[0050] The silicone oil is a mixture of methyl silicone oil and methyltrifluoropropyl silicone oil in a ratio of 85:15, and the filler is a mixture of alumina and zinc oxide in a ratio of 80:20. The mass ratio of the silicone oil, graphene suspension, and filler is 15%:10%:75%.

[0051] (5) Place the graphene thermal grease precursor in a constant temperature vacuum oven and heat it at 80°C for 7 hours to obtain the graphene thermal grease.

[0052] Example 3:

[0053] (1) Graphite was added to ultrapure water and stirred evenly. After ball milling for 1 hour, sand milling for 4 hours, and homogenization for 3 hours, graphene slurry was obtained. The graphene particle size in the prepared graphene slurry was 3-5 μm. The mass ratio of graphite to ultrapure water was 5:95.

[0054] (2) Filter the obtained graphene slurry, take the filter cake, add the transfer solvent to the filter cake, stir thoroughly, wash the graphene slurry with the transfer solvent, and filter; repeat the above operation twice to obtain a high-concentration graphene transfer solution. The mass concentration of graphene in the high-concentration graphene transfer solution is 80%. The transfer solvent is a mixture of methanol and ethylene glycol in a ratio of 40:60.

[0055] (3) Add an oily dispersant to the high-concentration graphene transfer solution, stir evenly and then sonicate to obtain a graphene suspension.

[0056] The mass ratio of high-concentration graphene transfer solution to oily dispersant is 90:10; the oily dispersant is a mixture of zinc stearate and oleic acid in a ratio of 12:88.

[0057] (4) Add graphene suspension and filler to silicone oil, place it in a vacuum stirring vessel, set the vacuum degree to less than -0.08 MPa, set the rotation speed to 3000 rpm, and stir continuously for 24 hours. Obtain graphene thermal conductive silicone grease precursor.

[0058] The silicone oil is a mixture of methyl silicone oil and methyltrifluoropropyl silicone oil in a ratio of 85:15, and the filler is a mixture of alumina and zinc oxide in a ratio of 80:20. The mass ratio of the silicone oil, graphene suspension, and filler is 15%:15%:70%.

[0059] (5) Place the graphene thermal grease precursor in a constant temperature vacuum oven and heat it at 180°C for 10 hours to obtain the graphene thermal grease.

[0060] Example 4:

[0061] (1) Graphite was added to ultrapure water and stirred evenly. After ball milling for 1 hour, sand milling for 4 hours, and homogenization for 3 hours, an aqueous graphene slurry was obtained. The graphene particle size in the prepared graphene slurry was 3-5 μm. The mass ratio of graphite to ultrapure water was 5:95.

[0062] (2) Filter the obtained graphene slurry, take the filter cake, add the transfer solvent to the filter cake, stir thoroughly, wash the graphene slurry with the transfer solvent, and filter; repeat the above operation twice to obtain a high-concentration graphene transfer solution. The mass concentration of graphene in the high-concentration graphene transfer solution is 70%. The transfer solvent is methanol.

[0063] (3) Add an oily dispersant to the high-concentration graphene transfer solution, stir evenly and then sonicate to obtain a graphene suspension.

[0064] The mass ratio of high-concentration graphene transfer solution to oily dispersant is 90:10; the oily dispersant is a mixture of zinc stearate and oleic acid in a ratio of 12:88.

[0065] (4) Add graphene suspension and filler to silicone oil, place it in a vacuum stirring vessel, set the vacuum degree to less than -0.08 MPa, set the rotation speed to 2500 rpm, and stir continuously for 18 hours. Obtain graphene thermal conductive silicone grease precursor.

[0066] The silicone oil is a mixture of methyl silicone oil and methyltrifluoropropyl silicone oil in a ratio of 85:15, and the filler is a mixture of alumina and zinc oxide in a ratio of 80:20. The mass ratio of the silicone oil, graphene suspension, and filler is 15%:10%:75%.

[0067] (5) Place the graphene thermal grease precursor in a constant temperature vacuum oven and heat it at 150°C for 7 hours to obtain the graphene thermal grease.

[0068] Example 5:

[0069] (1) Graphite was added to ultrapure water and stirred evenly. After ball milling for 1 hour, sand milling for 4 hours, and homogenization for 3 hours, graphene slurry was obtained. The graphene particle size in the prepared graphene slurry was 3-5 μm. The mass ratio of graphite to ultrapure water was 5:95.

[0070] (2) Filter the obtained graphene slurry, take the filter cake, add the transfer solvent to the filter cake, stir thoroughly, wash the graphene slurry with the transfer solvent, and filter; repeat the above operation twice to obtain a high-concentration graphene transfer solution, in which the mass concentration of graphene is 70%. The transfer solvent is a mixture of methanol, ethanol and isopropanol in a ratio of 30:60:10.

[0071] (4) Add an oily dispersant to the high-concentration graphene transfer solution, stir evenly and then sonicate to obtain a graphene suspension.

[0072] The mass ratio of high-concentration graphene transfer solution to oily dispersant is 90:10; the oily dispersant is a mixture of zinc stearate and oleic acid in a ratio of 12:88.

[0073] (4) Add graphene suspension and filler to silicone oil, place it in a vacuum stirring vessel, set the vacuum degree to less than -0.08MPa, set the rotation speed to 2500rpm, and stir continuously for 18h. Obtain graphene thermal conductive silicone grease precursor.

[0074] The silicone oil is a mixture of methyl silicone oil and methyltrifluoropropyl silicone oil in a ratio of 85:15, and the filler is a mixture of alumina and zinc oxide in a ratio of 80:20. The mass ratio of the silicone oil, graphene suspension, and filler is 15%:10%:75%.

[0075] (5) Place the graphene thermal grease precursor in a constant temperature vacuum oven and heat it at 150°C for 7 hours to obtain the graphene thermal grease.

[0076] Example 6:

[0077] (1) Graphite was added to ultrapure water and stirred evenly. After ball milling for 1 hour, sand milling for 4 hours, and homogenization for 3 hours, an aqueous graphene slurry was obtained. The graphene particle size in the prepared graphene slurry was 3-5 μm. The mass ratio of graphite to ultrapure water was 5:95.

[0078] (2) Filter the obtained graphene slurry, take the filter cake, add the transfer solvent to the filter cake, stir thoroughly, wash the graphene slurry with the transfer solvent, and filter; repeat the above operation twice to obtain a high-concentration graphene transfer solution. The mass concentration of graphene in the high-concentration graphene transfer solution is 70%. The transfer solvent is a mixture of methanol and ethylene glycol in a ratio of 40:60.

[0079] (3) Add an oily dispersant to the high-concentration graphene transfer solution, stir evenly and then sonicate to obtain a graphene suspension.

[0080] The mass ratio of high-concentration graphene transfer solution to oily dispersant is 90:10; the oily dispersant is a mixture of zinc stearate and oleic acid in a ratio of 12:88.

[0081] (4) Add graphene suspension and filler to silicone oil, place it in a vacuum stirring vessel, set the vacuum degree to less than -0.08 MPa, set the rotation speed to 2500 rpm, and stir continuously for 18 hours. Obtain graphene thermal conductive silicone grease precursor.

[0082] The silicone oil is a mixture of methyl silicone oil and methyl trifluoropropyl silicone oil in a ratio of 85:15, and the filler is alumina.

[0083] The mass ratio of the silicone oil, graphene suspension and filler is 15%:10%:75%.

[0084] (5) Place the graphene thermal grease precursor in a constant temperature vacuum oven and heat it at 150°C for 7 hours to obtain the graphene thermal grease.

[0085] Example 7:

[0086] (1) Graphite was added to ultrapure water and stirred evenly. After ball milling for 1 hour, sand milling for 4 hours, and homogenization for 3 hours, graphene slurry was obtained. The graphene particle size in the prepared graphene slurry was 3-5 μm. The mass ratio of graphite to ultrapure water was 5:95.

[0087] (2) Filter the obtained graphene slurry, take the filter cake, add the transfer solvent to the filter cake, stir thoroughly, wash the graphene slurry with the transfer solvent, and filter; repeat the above operation twice to obtain a high-concentration graphene transfer solution with a graphene mass concentration of 70%. The transfer solvent is a mixture of methanol and ethylene glycol in a ratio of 40:60.

[0088] (6) Add an oily dispersant to the high-concentration graphene transfer solution, stir evenly and then sonicate to obtain a graphene suspension.

[0089] The mass ratio of high-concentration graphene transfer solution to oily dispersant is 90:10; the oily dispersant is a mixture of zinc stearate and oleic acid in a ratio of 85:15.

[0090] (4) Add graphene suspension and filler to silicone oil, place it in a vacuum stirring vessel, set the vacuum degree to less than -0.08MPa, set the rotation speed to 2500rpm, and stir continuously for 18h. Obtain graphene thermal conductive silicone grease precursor.

[0091] The silicone oil is a mixture of methyl silicone oil and methyltrifluoropropyl silicone oil in a ratio of 85:15, and the filler is a mixture of alumina, boron nitride, and zinc oxide in a ratio of 60:20:20. The mass ratio of the silicone oil, graphene suspension, and filler is 15%:10%:75%.

[0092] (5) Place the graphene thermal grease precursor in a constant temperature vacuum oven and heat it at 150°C for 7 hours to obtain the graphene thermal grease.

[0093] Comparative Example 1:

[0094] (1) Graphite was added to ultrapure water and stirred evenly. After ball milling for 1 hour, sand milling for 4 hours, and homogenization for 3 hours, graphene slurry was obtained. The graphene particle size in the prepared graphene slurry was 3-5 μm. The mass ratio of graphite to ultrapure water was 5:95.

[0095] (2) Take the filtered graphene slurry, add the filter cake to the silicone oil, add the filler, place it in a vacuum stirring vessel, set the vacuum degree to less than -0.08MPa, set the rotation speed to 2500rpm, and stir continuously for 18h. Graphene thermal conductive silicone grease precursor is obtained.

[0096] (3) Place the above graphene thermal grease in a constant temperature vacuum oven at 150°C and heat for 7 hours to obtain graphene thermal grease.

[0097] Comparative Example 2:

[0098] (1) Add graphite to an oily dispersant, stir evenly, and then process by ball milling for 1 hour, sand milling for 4 hours, and homogenization for 3 hours to obtain an oily graphene slurry.

[0099] The oily dispersant is a mixture of zinc stearate and oleic acid in a ratio of 12:88, the graphene particle size is 3-4μm, and the mass ratio of graphite to oily dispersant is 5:95.

[0100] (2) After stirring the obtained graphene slurry evenly, it is ultrasonically homogenized to obtain a graphene suspension.

[0101] (3) Add graphene suspension and filler to silicone oil, place it in a vacuum stirring vessel, set the vacuum degree to less than -0.08 MPa, set the rotation speed to 2500 rpm, and stir continuously for 18 h. Obtain graphene thermal conductive silicone grease precursor.

[0102] The silicone oil is a mixture of methyl silicone oil and methyltrifluoropropyl silicone oil in a ratio of 85:15, and the filler is a mixture of alumina and zinc oxide in a ratio of 80:20. The mass ratio of the silicone oil, graphene suspension, and filler is 15%:10%:75%.

[0103] (5) Place the graphene thermal grease precursor in a constant temperature vacuum oven and heat it at 150°C for 7 hours to obtain the graphene thermal grease.

[0104] The thermal greases obtained in Examples 1-6 and Comparative Examples 1-2 were tested, and their thermal conductivity, volume resistivity and volatile content were measured respectively. The results are shown in Table 1.

[0105] The test method for thermal conductivity is as follows: the test method is the same as that for the standard ASTM D5470 Thermal Conductivity Electrical Insulating Materials Thermal Transfer Properties, the test instrument is the DRL-III thermal conductivity tester, and the test environment temperature is 20-25℃.

[0106] The volume resistivity test method is as follows: adopt the standard "ASTM D257 Test Method for DC Resistance or Conductivity of Insulating Materials", the instrument is ST2643 ultra-high resistance microcurrent tester, and the test environment temperature is 20-25℃.

[0107] The test method for volatile matter is as follows: adopt the standard "SH / T 0324-2010NB Determination of Oil Separation of Lubricating Grease by Conical Mesh Method", the instrument is a standard conical mesh and glassware, and the sample is placed in an oven at 100℃ (±0.1℃) for 30 hours continuously, and the weight change of the sample before and after is measured.

[0108]

[0109] Table 1. Performance Test Results

[0110] According to the data recorded in Table 1, as well as the SEM images of Example 1 and Comparative Example 1, the graphene dispersion uniformity in the thermal grease prepared by the method of washing graphene with a transfer solvent and preparing an oily dispersant is greatly improved, which effectively solves the problem of graphene agglomeration and curling in the matrix, thereby improving the thermal conductivity of the graphene thermal grease.

[0111] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing graphene thermal grease, characterized in that, Includes the following steps: S1. Graphite was added to ultrapure water and stirred evenly. After ball milling for 1 hour, sand milling for 4 hours, and homogenization for 3 hours, graphene slurry was obtained. S2. Filter the obtained graphene slurry, take the filter cake, add the transfer solvent and stir, wash the graphene slurry with the transfer solvent, filter, and repeat the above operation twice to obtain a high-concentration graphene transfer solution; the mass concentration of graphene in the high-concentration graphene transfer solution is 80%, and the transfer solvent is a mixture of methanol and ethylene glycol in a ratio of 40:

60. S3 adds an oily dispersant to a high-concentration graphene transfer solution, stirs until homogenized by ultrasonication, and obtains a graphene suspension; the oily dispersant is a mixture of zinc stearate and oleic acid in a ratio of 12:88; the mass ratio of the high-concentration graphene transfer solution to the oily dispersant is 90:

10. S4. The obtained oily graphene suspension and filler are added to silicone oil and stirred continuously in a vacuum stirring vessel for 2-24 hours to obtain a graphene thermal conductive silicone grease precursor. The silicone oil is a mixture of methyl silicone oil and methyl trifluoropropyl silicone oil in a ratio of 85:

15. The filler is a mixture of alumina and zinc oxide in a ratio of 80:

20. The mass ratio of the silicone oil, graphene suspension and filler is 15%:15%:70%. S5 places the graphene thermal grease precursor in a constant temperature vacuum oven and heats it for 1-10 hours to obtain the graphene thermal grease.

2. The method for preparing graphene thermal grease according to claim 1, characterized in that: The graphene particle size in the graphene slurry obtained in step S1 is 3-5 μm.

3. The method for preparing a graphene thermal grease according to claim 1, characterized in that: The mass ratio of graphite to ultrapure water in step S1 is 1-5:99-95.

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