Preparation method of recycled graphene film composite heat-conducting substrate

Abstract

The invention discloses a preparation method of a recycled graphene film composite heat-conducting substrate, which comprises the following steps: preparing graphite powder from recycled graphene film waste: recycling the graphene film waste, and crushing the recycled graphene film waste to obtain graphene powder with the size of 40-100 meshes; the recovered graphene film waste is crushed and sieved to obtain graphene powder with the size of 100 meshes; according to the graphene heat-conducting substrate, the recycled graphene waste and the expanded graphite are integrated, the graphene waste and the expanded graphite serve as heat-conducting filler and have excellent heat conductivity, the heat conductivity of the heat-conducting substrate can be improved through introduction of graphene, particles of the heat-conducting filler are in close contact with one another through wrapping of the graphene filler and the expanded graphite, and a heat-conducting channel is formed; the waste graphene leftover materials are recycled, waste is turned into wealth, resources are saved, a product with a high additional value is prepared, energy conservation and emission reduction can be achieved in the aspect of environmental protection, and cost can be reduced and benefit can be increased in the aspect of cost.

Description

Technical Field

[0001] The invention relates to the technical field of heat-conducting substrates, and in particular to a method for preparing a recycled graphene film composite heat-conducting substrate. Background Art

[0002] With the development of today's science and technology, electronic components are miniaturized and miniaturized. Integrated circuits are developing towards multifunctionality, high integration, high frequency and high power. The heat dissipation problem is one of the important factors restricting the further development of electronic products. The heat generated by electronic products during operation will only accumulate more and more if the heat is not discharged to the outside world in time, resulting in reduced product reliability and affecting user experience. Studies have shown that for every 2°C increase in the temperature of electronic products during operation, its reliability performance decreases by about 10%. When the operating temperature is 50°C, the life of electronic components is only 1 / 6 of that at an operating temperature of 25°C.

[0003] The heat dissipation methods of electronic products are divided into active heat dissipation and passive heat dissipation. Active heat dissipation is achieved by optimizing the internal design of electronic components to reduce energy consumption and thus reduce heat generation. Passive heat dissipation achieves heat dissipation by reducing the thermal resistance between thermal conductive materials and devices. The surface roughness between electronic components and radiators, there is air and vacuum. It is a thermal insulator, so thermal interface materials are needed to fill this gap. Thermal interface materials are a kind of material commonly used in semiconductor packaging and heat dissipation. They are used as fillers between the two interfaces of heat source and heat sink to reduce thermal resistance in the heat transfer process, improve heat transfer efficiency, and thus reduce the temperature of the electronic components themselves.

[0004] Graphene is a two-dimensional film composed of carbon atoms in a hexagonal honeycomb lattice with sp2 hybrid orbitals. Although it is thin, its structure is very stable. The primitive unit cell of graphene is defined by lattice vectors a1 and a2. There are two atoms in each primitive cell, located on the lattices A and B respectively. The three outer electrons of carbon atoms form strong σ bonds through sp2 hybridization. The angle between two adjacent bonds is (120°), and the fourth electron is public, forming a weak π bond. The carbon-carbon bond length of graphene is about 0.142nm. There are three σ bonds in each lattice. The p orbitals of all carbon atoms are perpendicular to the sp2 hybridization plane, and form a delocalized π bond in a shoulder-to-shoulder manner, running through the entire graphene.

[0005] Graphene has many excellent properties. For example, the valence band and conduction band of graphene intersect at one point (Dirac point), and there is no band gap between the two cone angles, so graphene is also called a zero-bandgap semiconductor. The electron mobility of graphene is very high, and can reach 250,000cm2·V-1·s-1 when measured at room temperature. The resistivity is 10-6Ω·cm, which is lower than that of silver and copper, and is currently the material with the lowest resistivity. The thermal conductivity is also as high as 5300W / (m·k). The Young's modulus is 1TPa, the inherent strength is 130GPa, and the large specific surface area is 2630m2 / g. It is precisely because of these excellent properties that it is widely used in the field of heat dissipation.

[0006] As the output of graphene films increases, the current Chinese graphene material market is mainly dominated by graphene powders. In 2022, graphene powders accounted for 90.7% of the overall market, and graphene films accounted for 9.3%. Graphene films are mainly produced through the coating process. During the start-up and adjustment of the machine before and after coating, there will be a large number of unqualified products. These unqualified products are treated as industrial waste, and the treatment of these industrial wastes requires 400-600 yuan per ton, which will cause great waste and increase costs. Summary of the invention

[0007] In order to solve the defects of the prior art, the present invention provides a method for preparing a recycled graphene film composite thermally conductive substrate.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0009] The present invention provides a method for preparing a recycled graphene film composite thermally conductive substrate, comprising the following steps:

[0010] (1) Preparation of graphite powder from recycled graphene film waste: Recycling graphene film waste, crushing the recycled graphene film waste to obtain graphene powder with a size of 40-100 mesh, and crushing and sieving the recycled graphene film waste to obtain graphene powder with a size of 100 mesh;

[0011] (2) Preparation of recycled graphene film waste and expanded graphite: mixing graphene powder with expanded graphite at concentrations of 10%, 30%, and 50% to obtain graphene / expanded graphite with different concentration ratios of 10%, 30%, and 50% of graphene powder;

[0012] (3) Preparation of graphene thermal conductive substrate: Graphene powder and expanded graphite were mixed at a temperature of 1.2 g / cm 3 , 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3The density of the tablets was used to press the graphene. 10%, 30%, and 50% of the graphene were mixed with expanded graphite, respectively, and put into the powder tablet mold. The mold was assembled and placed on the press. The press was calculated to press into 1.2g / cm 3 , 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 density.

[0013] As a preferred technical solution of the present invention, in the step (3), graphene with a concentration of 10%, 30%, and 50% is pre-pressed into sheets with expanded graphite, and the pre-pressed graphene sheets and expanded graphite sheets are pressed into 1.2 g / cm according to the rule of stacking one graphene sheet on top of another expanded graphite sheet and then stacking one graphene sheet. 3 , 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 density.

[0014] As a preferred technical solution of the present invention, in the step (3), the pressed graphene / expanded graphite is rolled uniformly using a double-roller machine.

[0015] As a preferred technical solution of the present invention, in the step (3), the rolled graphene / expanded graphite thermal conductive substrate is tested for its temperature uniformity using a thermocouple temperature tester.

[0016] As a preferred technical solution of the present invention, in the step (3), the rolled graphene / expanded graphite thermal conductive substrate is tested for its thermal conductivity using a laser thermal conductivity instrument.

[0017] As a preferred technical solution of the present invention, the size of the powder tableting mold in step (3) is 150mm*150mm*1mm.

[0018] As a preferred technical solution of the present invention, in the step (3), tableting is performed on a 50-ton press, pre-pressed for 3 minutes, depressurized and exhausted, and the tablets are pressed again for 30 minutes before exhausting and depressurizing to take out the substrate.

[0019] As a preferred technical solution of the present invention, the pressed uniform temperature substrate is tested for 1 hour at a power of 2.5 W using a thermocouple data collector.

[0020] The beneficial effects of the present invention are:

[0021] The preparation method of the recycled graphene film composite thermally conductive substrate, the graphene thermally conductive substrate combines recycled graphene waste and expanded graphite, and has excellent thermal conductivity as a thermally conductive filler. The introduction of graphene can improve the thermal conductivity of the thermally conductive substrate. The graphene filler is wrapped with expanded graphite, so that the particles of the thermally conductive filler are in close contact with each other, forming a thermal conductive path, so that the thermally conductive substrate has good thermal conductivity. The waste graphene scraps are recycled, turned into treasure, and resources are saved to prepare high value-added products. Not only can energy saving and emission reduction be achieved in terms of environmental protection, but also cost reduction and profit increase can be achieved in terms of cost. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present invention are described below. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0023] Embodiment 1: A method for preparing a recycled graphene film composite thermally conductive substrate according to the present invention comprises the following steps:

[0024] (1) Preparation of graphite powder from recycled graphene film waste: Recycling graphene film waste, crushing the recycled graphene film waste to obtain graphene powder with a size of 40-100 mesh, and crushing and sieving the recycled graphene film waste to obtain graphene powder with a size of 100 mesh;

[0025] (2) Preparation of recycled graphene film waste and expanded graphite: mixing graphene powder with expanded graphite at concentrations of 10%, 30%, and 50% to obtain graphene / expanded graphite with different concentration ratios of 10%, 30%, and 50% of graphene powder;

[0026] (3) Preparation of graphene thermal conductive substrate: Graphene powder and expanded graphite were mixed at a temperature of 1.2 g / cm 3 The density of the tablets was used to press the graphene. 10%, 30%, and 50% of the graphene were mixed with expanded graphite, respectively, and put into the powder tablet mold. The mold was assembled and placed on the press. The press was calculated to press into 1.2g / cm 3 density.

[0027]

[0028] Wherein, in the step (3), graphene with a concentration of 10%, 30%, and 50% is pre-pressed into sheets with expanded graphite, and the pre-pressed graphene sheets and expanded graphite sheets are pressed into a sheet of 1.2 g / cm according to the rule of stacking one graphene sheet on top of another expanded graphite sheet and then stacking one graphene sheet. 3 density.

[0029] Wherein, in the step (3), the pressed graphene / expanded graphite is rolled uniformly using a double-roller machine.

[0030] Wherein, in the step (3), the rolled graphene / expanded graphite thermal conductive substrate is tested for its temperature uniformity using a thermocouple temperature tester.

[0031] Wherein, in the step (3), the rolled graphene / expanded graphite thermal conductive substrate is tested for its thermal conductivity using a laser thermal conductivity instrument.

[0032] Wherein, the size of the powder tableting mold in step (3) is 150mm*150mm*1mm.

[0033] Wherein, in the step (3), tablet pressing is performed in a 50-ton press, pre-pressing for 3 minutes and then venting and exhausting the pressure, and then tablet pressing is performed again for 30 minutes and then the pressure is released and the substrate is taken out.

[0034] The pressed uniform temperature substrate was tested for 1 hour at a power of 2.5 W using a thermocouple data collector.

[0035] It can be seen from Table 1 that the higher the graphene concentration ratio, the better the thermal conductivity of the thermally conductive substrate obtained by compounding the recycled graphene film and expanded graphite.

[0036] Embodiment 2: A method for preparing a recycled graphene film composite thermally conductive substrate according to the present invention comprises the following steps:

[0037] (1) Preparation of graphite powder from recycled graphene film waste: Recycling graphene film waste, crushing the recycled graphene film waste to obtain graphene powder with a size of 40-100 mesh, and crushing and sieving the recycled graphene film waste to obtain graphene powder with a size of 100 mesh;

[0038] (2) Preparation of recycled graphene film waste and expanded graphite: mixing graphene powder with expanded graphite at concentrations of 10%, 30%, and 50% to obtain graphene / expanded graphite with different concentration ratios of 10%, 30%, and 50% of graphene powder;

[0039] (3) Preparation of graphene thermal conductive substrate: Graphene powder and expanded graphite were mixed at a temperature of 1.3 g / cm 3 The density of the tablets was calculated by mixing graphene with expanded graphite at concentrations of 10%, 30%, and 50%, respectively, and putting them into a powder tableting mold. The mold was assembled and placed on a press, and the press was calculated to be 1.3g / cm 3 density.

[0040]

[0041]

[0042] Wherein, in the step (3), graphene with a concentration of 10%, 30%, and 50% is pre-pressed into sheets with expanded graphite, and the pre-pressed graphene sheets and expanded graphite sheets are pressed into a sheet of 1.3 g / cm according to the rule of stacking one graphene sheet on top of another expanded graphite sheet and then stacking one graphene sheet. 3 density.

[0043] Wherein, in the step (3), the pressed graphene / expanded graphite is rolled uniformly using a double-roller machine.

[0044] Wherein, in the step (3), the rolled graphene / expanded graphite thermal conductive substrate is tested for its temperature uniformity using a thermocouple temperature tester.

[0045] Wherein, in the step (3), the rolled graphene / expanded graphite thermal conductive substrate is tested for its thermal conductivity using a laser thermal conductivity instrument.

[0046] Wherein, the size of the powder tableting mold in step (3) is 150mm*150mm*1mm.

[0047] Wherein, in the step (3), tablet pressing is performed in a 50-ton press, pre-pressing for 3 minutes and then venting and exhausting the pressure, and then tablet pressing is performed again for 30 minutes and then the pressure is released and the substrate is taken out.

[0048] The pressed uniform temperature substrate was tested for 1 hour at a power of 2.5 W using a thermocouple data collector.

[0049] It can be seen from Table 2 that the higher the graphene concentration ratio, the better the thermal conductivity of the thermally conductive substrate obtained by compounding the recycled graphene film and expanded graphite.

[0050] Embodiment 3: A method for preparing a recycled graphene film composite thermally conductive substrate according to the present invention comprises the following steps:

[0051] (1) Preparation of graphite powder from recycled graphene film waste: Recycling graphene film waste, crushing the recycled graphene film waste to obtain graphene powder with a size of 40-100 mesh, and crushing and sieving the recycled graphene film waste to obtain graphene powder with a size of 100 mesh;

[0052] (2) Preparation of recycled graphene film waste and expanded graphite: mixing graphene powder with expanded graphite at concentrations of 10%, 30%, and 50% to obtain graphene / expanded graphite with different concentration ratios of 10%, 30%, and 50% of graphene powder;

[0053] (3) Preparation of graphene thermal conductive substrate: Graphene powder and expanded graphite were mixed at a temperature of 1.4 g / cm 3The density of the tablets was used to press the graphene. 10%, 30%, and 50% of the graphene were mixed with expanded graphite, respectively, and put into the powder tablet mold. The assembled mold was placed on the press, and the press was calculated to be 1.4g / cm 3 density.

[0054]

[0055] Wherein, in the step (3), graphene with a concentration of 10%, 30%, and 50% is pre-pressed into sheets with expanded graphite, and the pre-pressed graphene sheets and expanded graphite sheets are pressed into a sheet of 1.4 g / cm according to the rule of stacking one graphene sheet on top of another expanded graphite sheet and then stacking one graphene sheet. 3 density.

[0056] Wherein, in the step (3), the pressed graphene / expanded graphite is rolled uniformly using a double-roller machine.

[0057] Wherein, in the step (3), the rolled graphene / expanded graphite thermal conductive substrate is tested for its temperature uniformity using a thermocouple temperature tester.

[0058] Wherein, in the step (3), the rolled graphene / expanded graphite thermal conductive substrate is tested for its thermal conductivity using a laser thermal conductivity instrument.

[0059] Wherein, the size of the powder tableting mold in step (3) is 150mm*150mm*1mm.

[0060] Wherein, in the step (3), tablet pressing is performed in a 50-ton press, pre-pressing for 3 minutes and then venting and exhausting the pressure, and then tablet pressing is performed again for 30 minutes and then the pressure is released and the substrate is taken out.

[0061] The pressed uniform temperature substrate was tested for 1 hour at a power of 2.5 W using a thermocouple data collector.

[0062] It can be seen from Table 3 that the higher the graphene concentration ratio, the better the thermal conductivity of the thermally conductive substrate obtained by compounding the recycled graphene film and expanded graphite.

[0063] Embodiment 4: A method for preparing a recycled graphene film composite thermally conductive substrate according to the present invention comprises the following steps:

[0064] (1) Preparation of graphite powder from recycled graphene film waste: Recycling graphene film waste, crushing the recycled graphene film waste to obtain graphene powder with a size of 40-100 mesh, and crushing and sieving the recycled graphene film waste to obtain graphene powder with a size of 100 mesh;

[0065] (2) Preparation of recycled graphene film waste and expanded graphite: mixing graphene powder with expanded graphite at concentrations of 10%, 30%, and 50% to obtain graphene / expanded graphite with different concentration ratios of 10%, 30%, and 50% of graphene powder;

[0066] (3) Preparation of graphene thermal conductive substrate: Graphene powder and expanded graphite were mixed at a temperature of 1.5 g / cm 3 The density of the tablets was used to press the graphene. 10%, 30%, and 50% of the graphene were mixed with expanded graphite, respectively, and put into the powder tablet mold. The mold was assembled and placed on the press. The press was calculated and pressed into 1.5g / cm 3 density.

[0067]

[0068]

[0069] In the step (3), graphene with a concentration of 10%, 30%, and 50% is pre-pressed into sheets with expanded graphite, and the pre-pressed graphene sheets and expanded graphite sheets are pressed into a sheet of 1.5 g / cm according to the rule of stacking one graphene sheet on top of another expanded graphite sheet and then stacking one graphene sheet. 3 density.

[0070] Wherein, in the step (3), the pressed graphene / expanded graphite is rolled uniformly using a double-roller machine.

[0071] Wherein, in the step (3), the rolled graphene / expanded graphite thermal conductive substrate is tested for its temperature uniformity using a thermocouple temperature tester.

[0072] Wherein, in the step (3), the rolled graphene / expanded graphite thermal conductive substrate is tested for its thermal conductivity using a laser thermal conductivity instrument.

[0073] Wherein, the size of the powder tableting mold in step (3) is 150mm*150mm*1mm.

[0074] Wherein, in the step (3), tablet pressing is performed in a 50-ton press, pre-pressing for 3 minutes and then venting and exhausting the pressure, and then tablet pressing is performed again for 30 minutes and then the pressure is released and the substrate is taken out.

[0075] The pressed uniform temperature substrate was tested for 1 hour at a power of 2.5 W using a thermocouple data collector.

[0076] It can be seen from Table 4 that the higher the graphene concentration ratio, the better the thermal conductivity of the thermally conductive substrate obtained by compounding the recycled graphene film and expanded graphite.

[0077] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a recycled graphene film composite thermally conductive substrate, characterized in that: The steps include: (1) Preparation of graphite powder from recycled graphene film waste: Recycling graphene film waste, crushing the recycled graphene film waste to obtain graphene powder with a size of 40 to 100 meshes, and crushing and sieving the recycled graphene film waste to obtain graphene powder with a size of 100 meshes; (2) Preparation of recycled graphene film waste and expanded graphite: mixing graphene powder with expanded graphite at concentrations of 10%, 30%, and 50% to obtain graphene / expanded graphite with different concentration ratios of 10%, 30%, and 50% of graphene powder; (3) Preparation of graphene thermal conductive substrate: Graphene powder and expanded graphite were mixed at a temperature of 1.2 g / cm 3 , 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 The density of the tablets was used to press the graphene. 10%, 30%, and 50% of the graphene were mixed with expanded graphite, respectively, and put into the powder tablet mold. The mold was assembled and placed on the press. The press was calculated to press into 1.2g / cm 3 , 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 density.

2. The method for preparing a recycled graphene film composite thermally conductive substrate according to claim 1, characterized in that: In the step (3), graphene with a concentration of 10%, 30%, and 50% is pre-pressed with expanded graphite into sheets, and the pre-pressed graphene sheets and expanded graphite sheets are pressed into a sheet of 1.2 g / cm according to the rule of stacking one graphene sheet on top of another expanded graphite sheet and then stacking one graphene sheet. 3 , 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 density.

3. The method for preparing a recycled graphene film composite thermally conductive substrate according to claim 2, characterized in that: In the step (3), the pressed graphene / expanded graphite is rolled uniformly using a double-roller machine.

4. The method for preparing a recycled graphene film composite thermally conductive substrate according to claim 3, characterized in that: In the step (3), the rolled graphene / expanded graphite thermal conductive substrate is tested for temperature uniformity using a thermocouple temperature tester.

5. The method for preparing a recycled graphene film composite thermally conductive substrate according to claim 4, characterized in that: In the step (3), the rolled graphene / expanded graphite thermal conductive substrate is tested for its thermal conductivity using a laser thermal conductivity instrument.

6. The method for preparing a recycled graphene film composite thermally conductive substrate according to claim 1, characterized in that: The size of the powder tableting mold in step (3) is 150mm*150mm*1mm.

7. The method for preparing a recycled graphene film composite thermally conductive substrate according to claim 1, characterized in that: In the step (3), tablets are pressed in a 50-ton press, pre-pressed for 3 minutes, and then depressurized and exhausted. After pressing again for 30 minutes, the pressure is exhausted and the substrate is taken out.

8. The method for preparing a recycled graphene film composite thermally conductive substrate according to claim 4, characterized in that: The pressed uniform temperature substrate was tested for 1 hour at a power of 2.5 W using a thermocouple data logger.

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