Ultralow-thermal-resistance liquid metal phase change gasket material and manufacturing method thereof

Abstract

The invention discloses an ultralow-thermal-resistance liquid metal phase change gasket material and a manufacturing method thereof, and belongs to the technical field of thermal interface heat conduction materials. The material comprises the following components in percentage by weight: 5-11% of resin, 5-14% of wax, 0.01-1% of antioxidant and the balance of liquid metal powder. The manufacturing method comprises the steps that the resin, the wax and the antioxidant are heated and stirred to form a liquid mixture, the liquid metal powder is added, then vacuum stirring is conducted, compression molding, cooling and cutting are conducted, and a finished product is obtained. The synergistic effect of all the components is achieved through a multi-element compound system, the heat conductivity coefficient of the product reaches 13.2-15.8 W / m.K, the heat resistance is as low as 0.008-0.014 DEG C * cm < 2 > / W, and the heat conducting agent can be widely applied to the field of heat management of high-power electronic devices.

Description

Technical Field

[0001] This invention relates to the field of organic thermally conductive materials for thermal interfaces, specifically to an ultra-low thermal resistance liquid metal phase change pad material and its manufacturing method. Background Technology

[0002] With the rapid development of industries such as artificial intelligence, big data, and new energy, electronic devices are rapidly iterating towards high performance, high integration, and miniaturization. Chip power density continues to rise, and thermal management has become a core bottleneck restricting the improvement of device performance, the extension of service life, and the assurance of reliability. Thermal interface materials (TIMs), as key materials for filling the interface gap between heat-generating devices and heat sinks, directly determine the heat transfer efficiency of the heat dissipation system. One of the core evaluation indicators is thermal resistance—lower thermal resistance enables rapid heat conduction, effectively preventing performance degradation or damage to devices due to overheating.

[0003] There are many types of thermal interface materials available, including graphene thermal pads, traditional phase change thermal pads, and thermal grease, but all of them have performance defects that are difficult to overcome. While solid thermal conductive materials such as graphene thermal pads have high nominal thermal conductivity, their solid state cannot fully fill the tiny gaps at the interface, easily leaving air gaps that significantly increase contact thermal resistance. Furthermore, they are prone to aging and cracking under long-term thermal cycling and mechanical vibration, and their thermal conductivity deteriorates sharply after separating from the interface, especially in ultra-thin heat dissipation spaces where the adhesion problem is more prominent. Traditional phase change thermal conductive pads can achieve a certain degree of interface filling through phase change, but their thermal conductivity is usually low due to the limitations of the substrate's thermal conductivity (e.g., some products have a nominal thermal conductivity of only 8.5 W / m·K), making it difficult to meet the low thermal resistance requirements of high-power devices. Although thermally conductive silicone grease materials have good fluidity, they are prone to volatilization and drying at high temperatures, have poor anti-aging and anti-pumping capabilities, and lack long-term reliability. Moreover, the thermal resistance of some products is still at a relatively high level of 0.03-0.06℃·cm² / W, which cannot meet the heat dissipation requirements of high-end electronic devices.

[0004] Liquid metals, as a class of metal alloys that remain liquid at room temperature or medium to low temperatures (such as gallium-based and indium-based alloys), possess outstanding advantages such as high intrinsic thermal conductivity (typically exceeding 70 W / m·K), excellent fluidity, and good thermal stability. They can achieve full interface filling and molecular-level wetting, fundamentally reducing contact thermal resistance, making them ideal candidates to replace traditional thermal conductive materials. However, pure liquid metal materials suffer from problems in practical applications such as easy leakage, lack of supporting structures, and poor construction operability, limiting their large-scale application in the field of thermal interface pads; while single-phase change thermal conductive pads, due to insufficient thermal conductivity, cannot meet the extreme pursuit of ultra-low thermal resistance in high-power devices.

[0005] Against this backdrop, combining the high thermal conductivity of liquid metal with the advantages of phase change thermal pads, such as controllable phase change, ease of construction, and structural stability, to develop a composite thermal interface pad with ultra-low thermal resistance has become a key technological direction for solving the current thermal management problems of high-power electronic devices. Summary of the Invention

[0006] Based on the problems existing in the background technology, the present invention provides a liquid metal phase change sheet made by combining liquid metal and phase change thermal pad, which aims to overcome the performance limitations of existing thermal interface materials, achieve low thermal resistance, high reliability and easy construction of heat conduction effect, and meet the stringent heat dissipation requirements of high-end electronic equipment, new energy devices and other fields.

[0007] This invention is implemented through the following technical solutions: An ultra-low thermal resistance liquid metal phase change pad material comprises the following components by weight percentage: 5%-11% resin, 5%-14% wax, 0.01%-1% antioxidant, and the balance being liquid metal powder.

[0008] Preferably, the resin is a mixture of two or more of the following: polybutadiene, polyolefin elastomer, ethylene-vinyl acetate copolymer, dihydroxyl-terminated polybutadiene, styrene-ethylene-butene-styrene block copolymer, and hydroxyl-terminated polybutadiene resin.

[0009] Preferably, the wax is a mixture of two or more of paraffin wax, microcrystalline wax, and silicone wax.

[0010] Preferably, the antioxidant is one or a mixture of two or more of antioxidants 1010, 168, 3114, and 1135.

[0011] Preferably, the liquid metal powder is a mixture of two or more of the following: bismuth-tin-lead alloy powder, bismuth-tin-cadmium alloy powder, bismuth-tin-zinc alloy powder, and bismuth-tin-antimony alloy powder.

[0012] This invention also provides a method for manufacturing the above-mentioned ultra-low thermal resistance liquid metal phase change pad material, comprising the following steps: Step 1. Weigh out 5%-11% resin, 5%-14% wax, and 0.01%-1% antioxidant by weight percentage; Step 2. Add the weighed resin, wax and antioxidant to a container equipped with an oil bath heating and stirring device, heat to 80-100℃, stir for 30-60 minutes to obtain a liquid mixture; Step 3. While maintaining the temperature of the liquid mixture at 80-100℃, add liquid metal powder, seal and connect to a vacuum system, evacuate to a vacuum degree of -0.08~-0.1MPa, heat to 100-120℃, stir for 30-60min to obtain a composite mixture; Step 4. Press the composite mixture into shape; Step 5. Cool to room temperature and cut into shape.

[0013] Preferably, the stirring speed in step 2 is 300-500 r / min.

[0014] Preferably, in step 3, liquid metal powder is added while stirring.

[0015] Preferably, in step 4, a calender is used for pressing and molding, with a pressure of 5-10 MPa, and the pressure is maintained for 30-40 minutes.

[0016] Preferably, ultraviolet laser cold cutting is used for cutting in step 5.

[0017] The beneficial effects of this invention are: 1. This invention achieves a synergistic effect among its components by employing a multi-component compound system. The multi-component resin compound provides a stable supporting structure, effectively solving the problems of easy leakage and lack of support in pure liquid metals. The multi-component wax compound achieves excellent phase change performance and interfacial wettability. Combined with the fluidity of liquid metal, it can fully fill the tiny gaps at the interface, fundamentally reducing contact thermal resistance and overcoming the defect of increased contact thermal resistance caused by the inability of solid thermal conductive materials to fully fill these gaps.

[0018] 2. This invention employs a controllable vacuum mixing and pressing process, resulting in consistent and stable product quality. The material has a sheet-like structure, facilitating cutting and installation, simplifying operation, and making it suitable for mass production and application. The material of this invention possesses ultra-low thermal resistance, high thermal conductivity, excellent interfacial filling properties, structural stability, and long-term reliability. It can be widely used in the thermal management of high-power-density electronic devices such as artificial intelligence chips, big data servers, new energy battery packs, power semiconductor devices, 5G communication equipment, and high-performance computing, solving the heat dissipation bottleneck problem faced by current high-end electronic devices due to continuously increasing power density. It has broad market application prospects and significant economic value. Detailed Implementation

[0019] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0020] The ultra-low thermal resistance liquid metal phase change pad material provided by the present invention comprises the following components by weight percentage: 5%-11% resin, 5%-14% wax, 0.01%-1% antioxidant, and the balance being liquid metal powder.

[0021] The resin is a mixture of two or more of the following: polybutadiene, polyolefin elastomer (POE), ethylene-vinyl acetate copolymer (EVA), dihydroxyl-terminated polybutadiene, styrene-ethylene-butene-styrene block copolymer (SEBS), and hydroxyl-terminated polybutadiene resin (HTPB).

[0022] The wax is a mixture of two or more of paraffin wax, microcrystalline wax, and silicone wax.

[0023] The antioxidant is one or a mixture of two or more of antioxidants 1010, antioxidant 168, antioxidant 3114, and antioxidant 1135.

[0024] The liquid metal powder is a mixture of two or more of the following: bismuth-tin-lead alloy powder, bismuth-tin-cadmium alloy powder, bismuth-tin-zinc alloy powder, and bismuth-tin-antimony alloy powder. Specifically, the bismuth-tin-lead alloy preferably has a Bi-Sn-Pb mass fraction of 48-52% bismuth, 26-32% lead, and 18-24% tin; the bismuth-tin-cadmium alloy preferably has a Bi-Sn-Cd mass fraction of 48-54% bismuth, 34-40% tin, and 8-16% cadmium; the bismuth-tin-zinc alloy preferably has a Bi-Sn-Zn mass fraction of 55-62% bismuth, 32-39% tin, and 4-10% zinc; and the bismuth-tin-antimony alloy preferably has a Bi-Sn-Sb mass fraction of 50-58% bismuth, 38-46% tin, and 2-8% antimony.

[0025] In the embodiments and comparative examples of the present invention, the liquid metal bismuth-tin-lead alloy used has a Bi-Sn-Pb mass fraction of 50% bismuth, 28% lead, and 22% tin; the bismuth-tin-cadmium alloy has a Bi-Sn-Cd mass fraction of 52% bismuth, 36% tin, and 12% cadmium; the bismuth-tin-zinc alloy has a Bi-Sn-Zn mass fraction of 57% bismuth, 35% tin, and 8% zinc; and the bismuth-tin-antimony alloy has a Bi-Sn-Sb mass fraction of 54% bismuth, 42% tin, and 4% antimony.

[0026] The preparation method of the material of the present invention includes the following steps: Step 1. Raw Material Weighing: Accurately weigh 5%-11% resin, 5%-14% wax, 0.01%-1% antioxidant, and the corresponding liquid metal powder according to the weight percentage of the designed formula. Ensure that the purity of each raw material meets the requirements and that there are no obvious impurities.

[0027] Step 2. Preparation of the basic liquid mixture: Place the weighed resin, wax, and antioxidant sequentially into a container equipped with an oil bath heating function and a stirring device. Start the oil bath heating and raise the temperature to 80-100℃, preferably 90℃. Simultaneously turn on the stirring function, controlling the stirring speed at 300-500 rpm, preferably 400 rpm, and continue stirring for 30-60 minutes. During this process, observe the state of the mixture to ensure that the resin and wax are completely melted, the antioxidant is fully dissolved, and a homogeneous, sediment-free, and non-stratified liquid mixture is formed.

[0028] Step 3. Add liquid metal powder and vacuum mix: While maintaining the temperature of the liquid mixture at 80-100℃, slowly add the weighed liquid metal powder to the container while stirring to prevent powder agglomeration. After the liquid metal powder is added, seal the container and connect it to a vacuum system with heating function. Start the vacuum pump and evacuate to a vacuum degree of -0.08~-0.1MPa. Then raise the oil bath temperature to 100-120℃ and continue stirring for 30-60 minutes. Under vacuum and heating conditions, the liquid metal powder is uniformly dispersed in the liquid mixture, and air bubbles in the mixture are expelled, resulting in a uniform, bubble-free composite mixture.

[0029] Step 4. Compression Molding: Clean the calender thoroughly beforehand, ensuring the surfaces of the upper and lower rollers are smooth and free of impurities. Adjust the distance between the upper and lower rollers according to the required product thickness. Quickly pour the vacuum-mixed composite mixture into the calender, ensuring the mixture is evenly distributed without voids or air bubbles. Start the calender and apply pressure to the mixture, controlling the pressure at 5-10 MPa. Maintain this pressure for 30-40 minutes, preferably 35 minutes, to fully compact the mixture into sheet material.

[0030] Step 5. Cooling and Post-processing: After pressing, turn off the heating device and remove the formed sheet sample. The sample can be cooled naturally to room temperature or accelerated by air cooling, but the cooling rate must be controlled to avoid internal stress caused by excessive cooling. After cooling, use precision cutting equipment (such as UV laser cold cutting equipment) to cut the sheet sample into finished products of different sizes and shapes according to actual needs. Perform a visual inspection on the finished products, and reject unqualified products with bubbles, cracks, or impurities on the surface. Seal and package qualified products for later use.

[0031] Thermal conductivity test: The test shall be conducted in accordance with ASTM D5470 standard using the heat flow method or transient plane heat source method.

[0032] Thermal resistance test: The test was conducted using a thermal resistance tester in accordance with ASTM D5470 standard.

[0033] Example 1: 55g of polyolefin elastomer (POE), 5g of hydroxyl-terminated polybutadiene resin (HTPB), 65g of paraffin wax, 10g of microcrystalline wax, 2.5g of antioxidant 1010, and 0.5g of antioxidant 168 were added to a mixer and heated to 90℃, then stirred for 40 minutes to obtain a liquid mixture. Maintaining the temperature at 100℃, 500g of bismuth-tin-zinc alloy powder and 347g of bismuth-tin-lead alloy powder were added while stirring and stirred until homogeneous. The mixture was then sealed and connected to a heated vacuum system, evacuated to -0.09MPa, and heated in an oil bath to 115℃, continuously stirred for 40 minutes to obtain a bubble-free composite mixture. The calender parameters were adjusted, the mixture was poured into the calender, and a pressure of 8MPa was applied, maintaining the pressure for 35 minutes to complete the molding process. The heating device was turned off, and the molded sample was allowed to cool naturally to room temperature. The sample was then cut into sheets using a UV laser cold cutting device.

[0034] Performance test results: Thermal conductivity is 15 W / m·K, thermal resistance is 0.009℃·cm 2 / W.

[0035] Example 2: 45g of ethylene-vinyl acetate copolymer (EVA), 25g of SEBS, 40g of microcrystalline wax, 25g of silicone wax, 1.8g of antioxidant 3114, and 1.2g of antioxidant 1135 were added to a mixer and heated to 90℃ and stirred for 40 minutes to obtain a liquid mixture. Maintaining the temperature at 100℃, 758g of liquid metal powder (380g of bismuth-tin-cadmium alloy powder + 378g of bismuth-tin-antimony alloy powder) was added while stirring and stirred until homogeneous. After sealing, the mixture was connected to a heated vacuum system and evacuated to -0.09MPa. The oil bath temperature was raised to 115℃, and stirring was continued for 40 minutes to obtain a bubble-free composite mixture. The calender parameters were adjusted, the mixture was poured into the calender, and a pressure of 9MPa was applied and maintained for 35 minutes to complete the molding process. The heating device was turned off, and the molded sample was allowed to cool naturally to room temperature. The sample was then cut into sheets using a UV laser cold cutting device.

[0036] Performance test results: Thermal conductivity is 14.2 W / m·K, thermal resistance is 0.010℃·cm. 2 / W.

[0037] Example 3: 70g of dihydroxy-terminated polybutadiene, 15g of polybutadiene, 90g of paraffin wax, 15g of silicone wax, 3.5g of antioxidant 1010, and 0.8g of antioxidant 3114 were added to a mixer and heated to 90℃ and stirred for 40 minutes to obtain a liquid mixture. Maintaining the temperature at 102℃, 609.7g of liquid metal powder (320g of bismuth-tin-lead alloy powder + 289.7g of bismuth-tin-zinc alloy powder) was added while stirring and stirred until homogeneous. After sealing, the mixture was connected to a heated vacuum system and evacuated to -0.095MPa. The oil bath temperature was raised to 115℃, and stirring was continued for 40 minutes to obtain a bubble-free composite mixture. The calender parameters were adjusted, the mixture was poured into the calender, and a pressure of 10MPa was applied and maintained for 35 minutes to complete the molding process. The heating device was turned off, and the molded sample was allowed to cool naturally to room temperature. The sample was then cut into sheets using a UV laser cold cutting device.

[0038] Performance test results: Thermal conductivity is 13.4 W / m·K, thermal resistance is 0.013℃·cm. 2 / W.

[0039] Example 4: 35g of polybutadiene, 25g of EVA, 85g of microcrystalline wax, 20g of paraffin wax, 1.2g of antioxidant 168, and 0.9g of antioxidant 1135 were added to a mixer and heated to 86℃ and stirred for 36 minutes to obtain a liquid mixture. Maintaining the temperature at 95℃, 668.9g of liquid metal powder (220g of bismuth-tin-lead alloy powder + 210g of bismuth-tin-cadmium alloy powder + 238.9g of bismuth-tin-antimony alloy powder) was added while stirring and stirred until homogeneous. After sealing, the mixture was connected to a heated vacuum system and evacuated to -0.088MPa. The oil bath temperature was raised to 110℃, and stirring was continued for 45 minutes to obtain a bubble-free composite mixture. The calender parameters were adjusted, the mixture was poured into the calender, and a pressure of 7MPa was applied and maintained for 37 minutes to complete the molding process. The heating device was turned off, and the molded sample was allowed to cool naturally to room temperature. The sample was then cut into sheets using a UV laser cold cutting device.

[0040] Performance test results: Thermal conductivity is 15.8 W / m·K, thermal resistance is 0.008℃·cm. 2 / W.

[0041] Example 5: 42g of dihydroxy-terminated polybutadiene, 18g of polyolefin elastomer (POE), 55g of silicone wax, 35g of microcrystalline wax, 2.3g of antioxidant 1010, and 2.7g of antioxidant 168 were added to a mixer and heated to 91℃ and stirred for 39 minutes to obtain a liquid mixture. Maintaining the temperature at 99℃, 775g of liquid metal powder (210g of bismuth-tin-lead alloy powder, 220g of bismuth-tin-zinc alloy powder, and 345g of bismuth-tin-cadmium alloy powder) was added while stirring and stirred until homogeneous. The mixture was then sealed and connected to a heated vacuum system, evacuated to -0.092MPa, and heated to 116℃ in an oil bath. Stirring was continued for 41 minutes to obtain a bubble-free composite mixture. The calender parameters were adjusted, the mixture was poured into the calender, and a pressure of 9MPa was applied and maintained for 34 minutes to complete the molding process. The heating device was turned off, and the molded sample was allowed to cool naturally to room temperature. The sample was cut into sheets using an ultraviolet laser cold cutting device.

[0042] Performance test results: Thermal conductivity is 14.0 W / m·K, thermal resistance is 0.012℃·cm. 2 / W.

[0043] Example 6: 32g of styrene-ethylene-butene-styrene block copolymer (SEBS), 28g of ethylene-vinyl acetate copolymer (EVA), 45g of paraffin wax, 48g of silicone wax, 3.6g of antioxidant 3114, and 1.4g of antioxidant 1135 were added to a mixer and heated to 89℃ and stirred for 37 minutes to obtain a liquid mixture. Maintaining the temperature at 101℃, 802g of liquid metal powder (160g of bismuth-tin-cadmium alloy powder + 145g of bismuth-tin-lead alloy powder + 497g of bismuth-tin-antimony alloy powder) was added while stirring and stirred until homogeneous. After sealing, the mixture was connected to a heated vacuum system and evacuated to -0.098MPa. The oil bath temperature was raised to 119℃, and stirring was continued for 39 minutes to obtain a bubble-free composite mixture. The calender parameters were adjusted, the mixture was poured into the calender, and a pressure of 8MPa was applied and maintained for 35 minutes to complete the molding process. The heating device was turned off, and the molded sample was allowed to cool naturally to room temperature. The sample was cut into sheets using an ultraviolet laser cold cutting device.

[0044] Performance test results: Thermal conductivity is 13.2 W / m·K, thermal resistance is 0.014℃·cm. 2 / W.

[0045] Comparative Example 1: Add 60g of polyolefin elastomer (POE), 70g of paraffin wax, and 3g of antioxidant 1010 to a mixer, heat to 90℃, and mix for 30 minutes to obtain a liquid mixture. Maintaining the temperature at 100℃, add 817g of bismuth-tin-lead alloy powder while stirring until homogeneous. After sealing, connect to a heated vacuum system, evacuate to -0.1MPa, heat the oil bath to 120℃, and continue stirring for 30 minutes to obtain a composite mixture. Adjust the calender parameters, pour the mixture into the calender, apply a pressure of 10MPa, and maintain for 40 minutes to complete the molding. Turn off the heating device and allow the molded sample to cool naturally to room temperature. Use an ultraviolet laser cold cutting device to cut the sample into sheets.

[0046] Performance test results: Thermal conductivity is 6.8 W / m·K, thermal resistance is 0.022℃·cm. 2 / W.

[0047] This invention overcomes the inherent limitations of single-component materials by employing a multi-component compound system. Any single resin, wax, or liquid metal alloy has performance limitations, making it difficult to simultaneously meet multiple requirements such as thermal conductivity, stability, and processability. This invention achieves complementary and synergistic performance enhancement by limiting the resin, wax, and liquid metal powder to two or more compound systems: the multi-resin compound compensates for their respective temperature sensitivities, improving long-term stability; the multi-wax compound achieves a gradient phase transition over a wide temperature range of 40-90℃, increasing the interfacial wettability from 60% to 95%; and the multi-liquid metal compound adjusts the melting point, enhances oxidation resistance, and generates a synergistic thermal conductivity effect, with measured thermal conductivity exceeding the theoretical weighted average.

[0048] A comparison of the examples and comparative examples reveals that the core advantage of this invention lies in the successful preparation of ultra-low thermal resistance liquid metal phase change gasket materials using a multi-component liquid metal alloy powder compound system, combined with a multi-component resin and an optimized wax ratio, along with controllable vacuum mixing and pressing molding processes. This type of material exhibits both ultra-high thermal conductivity (13.2-15.8 W / m·K) and extremely low thermal resistance (0.008-0.014 °C·cm). 2 / W).

[0049] Finally, it should be noted that the above embodiments are merely illustrative of several implementations of the present invention and are not intended to limit the scope of the invention. For those skilled in the art, any modifications, equivalent substitutions, or improvements made without departing from the concept of the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A liquid metal phase change pad material with ultra-low thermal resistance, characterized in that, The composition by weight percentage includes: 5%-11% resin, 5%-14% wax, 0.01%-1% antioxidant, and the balance being liquid metal powder.

2. The ultra-low thermal resistance liquid metal phase change pad material according to claim 1, characterized in that, The resin is a mixture of two or more of the following: polybutadiene, polyolefin elastomer, ethylene-vinyl acetate copolymer, dihydroxyl-terminated polybutadiene, styrene-ethylene-butene-styrene block copolymer, and hydroxyl-terminated polybutadiene resin.

3. The ultra-low thermal resistance liquid metal phase change pad material according to claim 1, characterized in that, The wax is a mixture of two or more of paraffin wax, microcrystalline wax, and silicone wax.

4. The ultra-low thermal resistance liquid metal phase change pad material according to claim 1, characterized in that, The antioxidant is one or a mixture of two or more of antioxidants 1010, antioxidant 168, antioxidant 3114, and antioxidant 1135.

5. The ultra-low thermal resistance liquid metal phase change pad material according to claim 1, characterized in that, The liquid metal powder is a mixture of two or more of the following: bismuth-tin-lead alloy powder, bismuth-tin-cadmium alloy powder, bismuth-tin-zinc alloy powder, and bismuth-tin-antimony alloy powder.

6. A method for manufacturing an ultra-low thermal resistance liquid metal phase change pad material according to any one of claims 1-5, characterized in that, Includes the following steps: Step 1. Weigh out 5%-11% resin, 5%-14% wax, and 0.01%-1% antioxidant by weight percentage; Step 2. Add the weighed resin, wax and antioxidant to a container equipped with an oil bath heating and stirring device, heat to 80-100℃, stir for 30-60 minutes to obtain a liquid mixture; Step 3. While maintaining the temperature of the liquid mixture at 80-100℃, add liquid metal powder, seal and connect to a vacuum system, evacuate to a vacuum degree of -0.08~-0.1MPa, heat to 100-120℃, stir for 30-60min to obtain a composite mixture; Step 4. Press the composite mixture into shape; Step 5. Cool to room temperature and cut into shape.

7. The manufacturing method according to claim 6, characterized in that, In step 2, the stirring speed is 300-500 r / min.

8. The manufacturing method according to claim 6, characterized in that, In step 3, add liquid metal powder while stirring.

9. The manufacturing method according to claim 6, characterized in that, In step 4, a calender is used for pressing and molding, with a pressure of 5-10 MPa, and the pressure is maintained for 30-40 minutes.

10. The manufacturing method according to claim 6, characterized in that, In step 5, ultraviolet laser cold cutting is used for cutting.