Preparation method and application of carbon-based composite material
Through the composite structure of graphite or graphene with polymer materials or fibers, combined with the infusion of silicon gel resin, the problems of industrial difficulty and insufficient thermal conductivity in the orientation process of existing carbon-based materials are solved, and efficient thermal conductivity and simplified processes are achieved.
Patent Information
- Application Number
- CN202510191352.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-20
- Publication Date
- 2025-05-27
AI Technical Summary
The existing ultra-high thermal conductivity carbon-based materials have industrial difficulties in the orientation process of mesophase bituminous carbon fibers, poor stability and room for improvement in thermal conductivity.
A composite structure of graphite or graphene and polymer materials or fibers is adopted to form a heat conduction channel through press molding and in-situ high-temperature treatment, and combined with the infusion of silicon gel resin to improve thermal conductivity.
It significantly improves the thermal conductivity of composite materials, simplifies processes, improves the stability and thermal conductivity of materials, and can meet the needs of high-performance materials in fields such as electronic devices and 5G communications.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of composite materials, and particularly to a preparation method and application of a carbon-based composite material. Background Art
[0002] With the rapid development of 5G communication technology, the thermal management of high-power heating devices has become an urgent problem to be solved; 5G communication devices, especially base stations and high-performance terminal devices, due to their high power and high integration, will generate a large amount of heat. If the heat cannot be dissipated in time, it will lead to a decline in device performance, shortening of service life, and even failures. Currently, the ultra-high thermal conductivity carbon-based materials on the market use mesophase pitch-based carbon fiber powder as the thermal conductive filler and silicone gel as the base material, and use processes such as strong magnetic field or strong shear to orient the carbon fiber powder, so as to obtain ultra-high thermal conductivity in the orientation direction. However, there are quite large industrial difficulties in orienting mesophase pitch-based carbon fibers at present, which is not conducive to production, has poor stability, and there is still room for improvement in thermal conductivity efficiency.
[0003] Therefore, it is of great practical significance to develop a new composite material with a simple preparation process and good thermal conductivity. Summary of the Invention
[0004] The purpose of the present invention is to propose a preparation method and application of a carbon-based composite material in view of the deficiencies existing in the prior art.
[0005] The inventors found that graphite or graphene, as anisotropic materials, have a high in-plane thermal conductivity (above 2000 W / mK), but a low interlayer thermal conductivity (10 - 30 W / mK). Therefore, it is necessary to prepare an anisotropic composite material by arranging graphite or graphene sheets in parallel, and then cut the cross-section into thin slices to obtain an anisotropic composite material with thermal conductivity in the direction of graphite or graphene sheets. However, for graphite or graphene, the addition of a binder will significantly reduce its thermal conductivity, and it is necessary to construct a dual structure that separates thermics and mechanics to effectively achieve this purpose.
[0006] The preparation method of the present invention is simple and easy to implement. Through the composite structure of graphite / graphene and polymer materials or fibers, an efficient thermal conduction channel is formed, which greatly improves the thermal conductivity of the composite material and meets the requirements of high-performance materials in the fields of electronic devices and 5G communication.
[0007] To solve the above problems, an embodiment of the present invention proposes a preparation method of a carbon-based composite material in the first aspect, which includes the following steps:
[0008] Step 1: Mix flaky graphite, expanded graphite or graphene with short-cut fibers or polymer material powders, place them in a mold, and press them into shape by a press;
[0009] Step 2: Subject the pressed sample to in-situ high-temperature treatment at 200 - 300 °C for 30 - 60 min to melt the fiber or polymer material powder to achieve in-situ pore formation, thereby obtaining a thermally conductive composite block;
[0010] Step 3: Pour silicone gel resin into the thermally conductive composite block for vacuum casting, and then cure it by heating to obtain a carbon-based composite.
[0011] According to the preparation method of a carbon-based composite in an embodiment of the present invention, first, graphite is pressed into shape with short-cut fibers or polymer materials, and then subjected to in-situ high-temperature treatment to achieve in-situ pore formation, forming a thermally conductive path. At the same time, the melting of the fibers plays a role in bonding and enhancing the strength of the graphite. After that, silicone is poured in to improve the elasticity; in this way, the formed thermally conductive channels are more complete, with smaller thermal resistance, and graphite itself also has an ultra-high thermal conductivity; compared with the orientation forming of mesophase pitch-based carbon fibers, the process is greatly simplified, and it has a good thermal conductivity, which can ensure the good operation of the device and meet the requirements of high-performance materials in the fields of electronic devices and 5G communication, etc.
[0012] Optionally, in Step 1, the short-cut fibers are short-cut polyester fibers, short-cut polypropylene fibers, or short-cut nylon fibers.
[0013] Optionally, in Step 1, the polymer material is one or more of polyethylene, polypropylene, polyoxyethylene, EVA, TPE, TPEE, EPDM, SBS, and SEBS.
[0014] Optionally, in Step 1, the diameter of the short-cut fibers is 100 - 300 μm, and the length is 0.5 - 5 mm.
[0015] Optionally, in Step 1, the forming pressure of the press is 0.5 - 200 MPa.
[0016] Optionally, in Step 1, the ratio of the flake graphite, expanded graphite, or graphene to the short-cut fibers or polymer material powder is 1:0.3 - 4.
[0017] Optionally, in Step 3, by weight, the silicone gel resin includes 50 parts of hydrogen-containing silicone oil, 5 parts of vinyl silicone oil, and 0.2 part of platinum catalyst.
[0018] Optionally, in Step 3, the time for vacuum casting is 10 - 20 min.
[0019] Optionally, in Step 3, heat to 120 °C and cure for 20 min.
[0020] In a second aspect, an embodiment of the present invention provides a thermal pad, which is obtained by cutting the carbon-based composite prepared by the above preparation method.
[0021] The thermal conductive gasket according to the embodiment of the present invention has a thermal conductivity far higher than that of market products, can greatly improve the heat dissipation efficiency, reduce the working temperature, and thus ensure the good operation of the device.
[0022] The additional aspects and advantages of the present invention will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the present invention. Detailed implementation manners
[0023] The technical solution of the present invention will be described below through specific specific examples. It should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combination steps or that other method steps can be inserted between these clearly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. Moreover, unless otherwise stated, the numbers of each method step are only convenient tools for identifying each method step, rather than limiting the arrangement order of each method step or the scope in which the present invention can be implemented. The change or adjustment of their relative relationship, without substantial change in technical content, should also be regarded as the scope in which the present invention can be implemented.
[0024] In order to better understand the above technical solution, the exemplary embodiments of the present invention will be described in more detail below. Although the exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to be able to convey the scope of the present invention completely to those skilled in the art.
[0025] The test materials used in the present invention are all ordinary commercially available products and can be purchased in the market.
[0026] The present invention will be described below with reference to specific embodiments. It should be noted that these embodiments are only descriptive and do not limit the present invention in any way.
[0027] Embodiment 1
[0028] Pressing and forming: According to parts by weight, 100 parts of flake graphite (500 - 3000 mesh) and 150 parts of chopped polyester fibers (diameter 100μm, length 1mm) are mixed by high-speed stirring. The mixed material is placed in an alloy mold and is pressed and formed by a press under the condition of a pressure of 20 MPa. When compressed by 50%, pressure relief and gas release are carried out, and this is repeated 5 - 10 times to ensure that the obtained composite material does not show delamination.
[0029] In-situ high-temperature treatment: Place the pressed sample in an oven and treat it at 240 °C for 45 minutes to melt the polyester fibers to form in-situ pores, creating continuous void channels. Meanwhile, the melted fibers enhance the bonding of the lamellar graphite. After cooling and taking out, a thermally conductive composite block with a density of 1.08 g / cm 3 is obtained.
[0030] Vacuum resin infusion: Prepare silicone gel resin, which consists of 50 parts of hydrogen-containing silicone oil, 5 parts of vinyl silicone oil, and 0.2 part of platinum catalyst. Place the thermally conductive composite block with pores in a container, pour in the prepared silicone gel resin, and perform resin infusion treatment under a vacuum of less than -0.09 MPa for 15 minutes. After taking out, heat it at 120 °C for 20 minutes for curing and forming to obtain the carbon-based composite material.
[0031] Cutting and forming: Cut the prepared carbon-based composite material into slices with dimensions of 20 mm × 20 mm × 0.2 mm for performance testing.
[0032] Example 2
[0033] Pressing and forming: Mix 100 parts of expanded graphite (expansion ratio of 200 times), 25 parts of chopped polyamide fibers (diameter 100 μm, length 2 mm), and 25 parts of polypropylene powder by high-speed stirring. Place the mixed material in an alloy mold and carry out pressure molding under a pressure of 100 MPa by a press. Release the pressure and vent gas each time the compressed volume reaches 50% to ensure that the obtained composite material does not show delamination.
[0034] In-situ high-temperature treatment: Place the pressed sample in an oven and treat it at 200 °C for 30 minutes to melt the polyamide fibers and polypropylene to form in-situ pores, creating continuous void channels. Meanwhile, the melted fibers enhance the bonding of the expanded graphite. After cooling and taking out, a thermally conductive composite block with a density of 1.05 g / cm 3 is obtained.
[0035] Vacuum resin infusion: Prepare silicone gel resin, which consists of 50 parts of hydrogen-containing silicone oil, 5 parts of vinyl silicone oil, and 0.2 part of platinum catalyst. Place the thermally conductive composite block with pores in a container, pour in the prepared silicone gel resin, and perform resin infusion treatment under a vacuum of -0.09 MPa for 15 minutes. After taking out, heat it at 120 °C for 20 minutes for curing and forming to obtain the carbon-based composite material.
[0036] Cutting and forming: Cut the prepared carbon-based composite material into slices with dimensions of 20 mm × 20 mm × 0.2 mm for performance testing.
[0037] Example 3
[0038] Compression molding: According to parts by weight, 100 parts of graphene (reduced graphene oxide or CVD graphene), 20 parts of chopped pitch fiber (diameter 100 μm, length 1 mm), and 100 parts of nylon 6 powder are mixed by high-speed stirring. The mixed material is placed in an alloy mold and pressure-molded by a press under a pressure of 80 MPa. When the compression volume is 50% each time, pressure relief and gas release are carried out to ensure that the obtained composite material does not show delamination.
[0039] In-situ high-temperature treatment: The compression-molded sample is placed in an oven and treated at a temperature of 300 °C for 30 minutes to melt the pitch fiber and nylon 6 to achieve in-situ pore formation, forming continuous void channels. At the same time, the melting of the fiber plays a role in bonding and strengthening the graphene; after cooling and taking out, a thermally conductive composite material block with a density of 1.08 g / cm 3 is obtained.
[0040] Vacuum potting: Prepare a silicone gel resin, which includes 50 parts of hydrogen-containing silicone oil, 5 parts of vinyl silicone oil, and 0.2 parts of platinum catalyst. The thermally conductive composite material block after pore formation is placed in a container, and the prepared silicone gel resin is poured in, and potting treatment is carried out under a vacuum of less than -0.09 MPa for 15 minutes. After taking out, it is cured at 120 °C for 20 minutes to form a carbon-based composite material.
[0041] Cutting and forming: The prepared carbon-based composite material is cut into slices with a size of 20 mm × 20 mm × 0.2 mm for performance testing.
[0042] Example 4
[0043] Compression molding: According to parts by weight, 100 parts of expanded graphite (expansion ratio of 300 times), 10 parts of chopped polypropylene fiber (diameter 200 μm, length 2 mm), and 50 parts of SEBS powder are mixed by high-speed stirring. The mixed material is placed in an alloy mold and pressure-molded by a press under a pressure of 30 MPa. When the compression volume is 50% each time, pressure relief and gas release are carried out to ensure that the obtained composite material does not show delamination.
[0044] In-situ high-temperature treatment: The compression-molded sample is placed in an oven and treated at a temperature of 250 °C for 30 minutes to melt the polypropylene fiber and SEBS to achieve in-situ pore formation, forming continuous void channels. At the same time, the melting of the fiber plays a role in bonding and strengthening the expanded graphite; after cooling and taking out, a thermally conductive composite material block with a density of 1.08 g / cm 3 is obtained.
[0045] Vacuum resin infusion: Prepare silicone gel resin, which consists of 50 parts of hydrogen-containing silicone oil, 5 parts of vinyl silicone oil, and 0.2 parts of platinum catalyst. Place the heat-conducting composite material block with pores formed above in a container, pour in the prepared silicone gel resin, and conduct resin infusion treatment under a vacuum of less than -0.09 MPa for 15 minutes. After taking it out, heat it to 120 °C for curing for 20 minutes to form a shape, thus obtaining the carbon-based composite material.
[0046] Cutting and forming: Cut the prepared carbon-based composite material into slices with dimensions of 20 mm × 20 mm × 0.2 mm for performance testing.
[0047] Example 5
[0048] Pressing and forming: According to parts by weight, mix 100 parts of expanded graphite (expansion ratio of 300 times) and 75 parts of SEBS powder by high-speed stirring. Place the mixed material in an alloy mold, and use a press to carry out pressure holding and forming under a pressure of 20 MPa. Release the pressure and vent the gas each time the compression volume reaches 50% to ensure that the obtained composite material does not show delamination.
[0049] In-situ high-temperature treatment: Place the sample after pressing and forming in an oven, and treat it at a temperature of 250 °C for 30 minutes to melt SEBS to form in-situ pores and create continuous void channels, while also playing a role in bonding and strengthening the expanded graphite; cool and take it out to obtain a heat-conducting composite material block with a density of 1.08 g / cm 3 ³.
[0050] Vacuum resin infusion: Prepare silicone gel resin, which consists of 50 parts of hydrogen-containing silicone oil, 5 parts of vinyl silicone oil, and 0.2 parts of platinum catalyst. Place the heat-conducting composite material block with pores formed above in a container, pour in the prepared silicone gel resin, and conduct resin infusion treatment under a vacuum of less than -0.09 MPa for 15 minutes. After taking it out, heat it to 120 °C for curing for 20 minutes to form a shape, thus obtaining the carbon-based composite material.
[0051] Cutting and forming: Cut the prepared carbon-based composite material into slices with dimensions of 20 mm × 20 mm × 0.2 mm for performance testing.
[0052] Comparative Example 1 (without in-situ high-temperature treatment)
[0053] Pressing and forming: According to parts by weight, mix 100 parts of flake graphite and 100 parts of chopped polyester fibers (diameter of 100 μm and length of 1 mm) by high-speed stirring. Place the mixed material in an alloy mold, and use a press to carry out pressure holding and forming under a pressure of 50 MPa. Release the pressure and vent the gas each time the compression volume reaches 50% to ensure that the obtained composite material does not show delamination.
[0054] Vacuum resin infusion: Prepare silicone gel resin, which consists of 50 parts of hydrogen-containing silicone oil, 5 parts of vinyl silicone oil, and 0.2 parts of platinum catalyst. Place the sample after the above-mentioned pressing and forming process in a container, pour in the prepared silicone gel resin, and perform resin infusion treatment for 15 minutes under a vacuum of less than -0.09 MPa. After taking it out, heat it at 120 °C for curing for 20 minutes to form a carbon-based composite material.
[0055] Cutting and forming: Cut the prepared carbon-based composite material into slices according to 20 mm × 20 mm × 0.2 mm for performance testing.
[0056] Test examples
[0057] Perform performance testing on the carbon-based composite materials prepared in Examples 1-4 and Comparative Example 1:
[0058] 1. Thermal conductivity: Tested using the steady-state heat flow method (ASTM D5470);
[0059] 2. Tensile strength: Tested using a universal material testing machine (ASTM D638);
[0060] 3. Thermal resistance: Tested using the steady-state heat flow method (ASTM D5470);
[0061] 4. Temperature resistance range test: IEC 60068-2-14.
[0062] Table 1: Main performance parameters of carbon-based composite materials
[0063]
[0064] The results are shown in Table 1. It can be seen from Table 1 that by first applying pressure to obtain the contact between graphite or graphene to form a heat conduction channel, then performing in-situ heating to melt the polymer material and fibers for in-situ reinforcement, and then performing silicone perfusion, a high thermal conductivity composite material is obtained. This method has a series of advantages such as simple process, good operability, and excellent product performance. Moreover, using expanded graphite, chopped fibers, and polymer materials to produce the product, the obtained composite material has a high thermal conductivity, excellent mechanical properties, and low thermal resistance.
[0065] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.
[0066] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.
Claims
1. A method for preparing a carbon-based composite material, characterized in that: The following steps are involved: Step 1: Mix flake graphite, expanded graphite or graphene with chopped fibers or polymer material powder, place them in a mold, and press them into shape using a press; Step 2: subjecting the pressed sample to an in-situ high temperature treatment at 200-300° C. for 10-60 min to melt the fiber or polymer material powder to achieve in-situ pore formation, thereby obtaining a thermally conductive composite material block; Step 3: Pour the silicone gel resin into the thermal conductive composite material block, perform vacuum filling, and heat and cure to obtain the carbon-based composite material.
2. The preparation method according to claim 1, characterized in that In step 1, the chopped fibers are chopped polyester fibers, chopped polypropylene fibers or chopped nylon fibers.
3. The preparation method according to claim 1, characterized in that: In step 1, the polymer material is one or more of polyethylene, polypropylene, polyethylene oxide, EVA, TPE, TPEE, EPDM, SBS, and SEBS.
4. The preparation method according to claim 1, characterized in that: In step 1, the chopped fibers have a diameter of 100-300 μm and a length of 0.5-5 mm.
5. The preparation method according to claim 1, characterized in that: In step 1, the molding pressure of the press is 0.5-200 MPa.
6. The preparation method according to claim 1, characterized in that: In step 1, the ratio of the flake graphite, expanded graphite or graphene to the chopped fibers or polymer material powder is 1:0.3-4.
7. The preparation method according to claim 1, characterized in that: In step 3, the silicone gel resin includes 50 parts of hydrogenated silicone oil, 5 parts of vinyl silicone oil, and 0.2 parts of platinum catalyst, in parts by weight.
8. The preparation method according to claim 1, characterized in that: In step 3, the vacuum filling time is 10-20 minutes.
9. The preparation method according to claim 1, characterized in that: In step 3, heat to 120°C and cure for 20 minutes.
10. A thermally conductive pad, characterized in that: The carbon-based composite material is obtained by cutting the carbon-based composite material obtained by the preparation method according to any one of claims 1 to 9.