High-heat-dissipation composite functional material for 3c products and preparation method thereof
By using a composite material with a carbon fiber-glass fiber ratio of 3:1 and gradient layup, combined with modified resin and a four-stage hot pressing process, the problems of lag in heat dissipation response, imbalance in mechanical properties, and high mass production costs of 3C product materials have been solved. This achieves a balance between efficient heat dissipation and mechanical properties, making it suitable for foldable screen terminals with high-power chips.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGXI DESIEN TECH CO LTD
- Filing Date
- 2026-04-02
- Publication Date
- 2026-07-28
AI Technical Summary
Existing materials have slow thermal response rates, which cannot meet the instantaneous heat generation requirements of 3C product chips; the mechanical properties of fiber composite systems are unbalanced, making it difficult to simultaneously meet the requirements of high rigidity (≥350MPa) and high toughness (≥22MPa) in terms of flexural strength; the interfacial bonding force between resin and fiber, and heat dissipation film is weak, with interlaminar shear strength ≤22MPa; mass production processes are complex and costly, equipment modification investments are large, and yield rates are low.
By adopting the optimal carbon fiber-glass fiber ratio of 3:1, combined with gradient lay-up and modified resin, a four-stage gradient hot pressing process was designed to optimize the through-hole parameters of the heat dissipation film. The interfacial bonding force was enhanced by a core-shell structured nano-silica-polyacrylate composite modifier, forming a sandwich-like laminated structure to ensure full resin curing.
It achieves high rigidity, lightweight, and instantaneous high heat dissipation performance, with bending strength ≥380MPa, impact resistance, interlaminar shear strength ≥28MPa, thermal response rate ≥4℃/min, temperature ≤85℃ within 10min, and compatibility with existing production lines. The equipment modification investment is ≤300,000 yuan, and the yield rate is increased to 92%.
Smart Images
Figure CN122463504A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of heat dissipation materials technology, and in particular to a high heat dissipation composite functional material for 3C products and its preparation method. Background Technology
[0002] As 3C products develop towards higher integration, thinner and lighter designs, and longer battery life, especially with increasingly stringent performance requirements for structural components in terminals such as foldable phones, the demands are becoming more stringent. On the one hand, flagship chips such as the Snapdragon 8 Gen3 and Kirin 9010 can deliver instantaneous power exceeding 3W, while traditional materials like ceramic / pure carbon fiber have a slow heat dissipation response rate of ≤3℃ / min, leading to chip performance throttling. On the other hand, structural components must simultaneously meet the requirements of lightweight density. The existing solutions have significant shortcomings in meeting the mechanical requirements of high rigidity bending strength ≥350MPa and resistance to 100,000 bends without peeling: ceramic cover plates have low density. Heavy weight, high impact resistance It is easily broken and has poor heat dissipation performance with a low thermal conductivity. Pure carbon fiber composite material with a flexural strength ≥400MPa, but low transverse thermal conductivity. The heat dissipation response is lagging, and the impact resistance is only... These technologies cannot meet the bending resistance requirements of foldable products. Traditional composite heat dissipation materials, such as the carbon fiber-glass fiber composite system disclosed in CN104552974A, have a carbon fiber content of only 4%. Although the bending strength is 521MPa, it does not involve heat dissipation structure design. The nano-silica modified epoxy resin disclosed in Chinese patent application 201210230325X only improves the shear strength and does not solve the interface bonding problem with the heat dissipation film. The interlayer shear strength is ≤22MPa, and the instantaneous heat dissipation requirements of 3C products are not considered. In terms of mass production processes, existing technologies either rely on building new dedicated production lines with an investment of over 1.5 million yuan, or the crude process parameters result in a yield of ≤85%, which cannot meet the needs of large-scale application in the 3C industry.
[0003] Therefore, developing a composite functional material with fast instantaneous heat dissipation response, balanced mechanical properties, and high feasibility for mass production has become a key technological breakthrough for upgrading structural components of 3C products. Summary of the Invention
[0004] In view of the above-mentioned shortcomings of the prior art, the technical problem to be solved by the present invention is that: the thermal response rate of existing materials is slow, usually ≤3℃ / min, which cannot meet the instantaneous heating requirements of 3C product chips; the mechanical properties of fiber composite systems are unbalanced, making it difficult to simultaneously meet the requirements of high rigidity (≥350MPa bending strength) and impact resistance. High toughness; weak interfacial bonding between resin and fiber, heat dissipation film, interlaminar shear strength ≤22MPa, easy to peel after folding; complex mass production process, high cost, large investment in equipment modification, and low yield.
[0005] This invention proposes a high-heat-dissipation composite material for 3C products that combines high rigidity, lightweight, and instantaneous high heat dissipation performance. It is specifically designed for 3C products such as foldable phones and laptops, and is especially suitable for foldable screen terminals equipped with high-power chips. This invention solves the technical pain points of existing materials, such as lag in heat dissipation response, imbalance in mechanical properties, and high mass production costs.
[0006] The technical concept of this invention originates from the industry pain point of performance throttling caused by instantaneous heat generation in foldable mobile phone chips in 2024: the initial solution was carbon fiber + pure graphite film, and after 15 failed tests, three core problems were found: ① Insufficient interfacial bonding between pure epoxy resin and fiber and graphite film, with an interlaminar shear strength of only 18MPa; ② Mechanical imbalance in the proportion of single carbon fiber, resulting in insufficient impact resistance. ③ The graphite film without through-holes exhibited a lag in heat dissipation response, with temperatures exceeding 95℃ within 10 minutes. Based on this, the following optimizations were made: a nano-silica-polyacrylate composite modifier was introduced to achieve a balance between resin rigidity and toughness through a core-shell structure, increasing interfacial bonding strength by 50%; the optimal carbon fiber-glass fiber ratio of 3:1 was determined through 20 orthogonal experiments, and combined with gradient layup, the mechanical imbalance problem was resolved; the through-hole parameters (pore size, proportion) of the heat dissipation film were optimized to synergistically improve the thermal response rate with the modified resin; a four-stage gradient hot-pressing process was designed to ensure full resin curing and reduce residual stress.
[0007] The specific technical solution is as follows: A high heat dissipation composite functional material for 3C products includes at least two composite material layers and at least one heat dissipation film, wherein the heat dissipation film is sandwiched between adjacent composite material layers to form a sandwich-type stacked structure of composite material layer-heat dissipation film-composite material layer; The composite material layer is made of carbon fiber prepreg and glass fiber prepreg in a weight ratio of 3:1 and is pressed together. The layup angle of each composite material layer is at least two combinations of 0°, 45° and 90°. The fiber mass fraction is 50%-70% and the balance is resin.
[0008] The heat dissipation film is a modified graphene composite graphite film or a modified artificial graphite film with a thickness of 0.1mm-0.3mm. The surface is uniformly distributed with through holes with a diameter of 0.3mm-0.5mm and a spacing of 1.5mm-2mm. The total area of the through holes accounts for 1-3% of the surface area of the heat dissipation film. The inner wall of the through holes is coated with a silane coupling agent layer with a thickness of 0.001mm-0.005mm. The silane coupling agent is KH-550 or KH-560.
[0009] The resin in the prepreg consists of 1wt%-3wt% nano-silica-polyacrylate composite modifier, 10wt%-20wt% curing agent, 1wt%-3wt% accelerator, and the balance bisphenol A epoxy resin. The nano-silica-polyacrylate composite modifier has a core-shell structure with a core particle size of 10nm-30nm and a shell composed of polyacrylate segments with a grafting rate ≥30%. The resin has a low thermal conductivity. The curing agent is diaminodiphenylmethane; the accelerator is 2-methylimidazole.
[0010] The density of the composite functional material is Flexural strength ≥380MPa, interlaminar shear strength ≥28MPa, impact strength Under 3W analog chip power, the surface temperature is ≤85℃ within 10 minutes, the thermal response rate is ≥4℃ / min, and the interlayer peeling rate is ≤5% after 100,000 bending cycles; The composite functional material is integrally formed by hot pressing, which employs a four-stage gradient heating process.
[0011] More preferably, the high heat dissipation composite functional material for 3C products includes a first composite material layer, a second composite material layer, and a third composite material layer. A first heat dissipation film is provided between the first composite material layer and the second composite material layer, and a second heat dissipation film is provided between the second composite material layer and the third composite material layer. The layup angle of the first composite material layer is 0°, the layup angle of the second composite material layer is 45° or 90°, and the layup angle of the third composite material layer is 0° or 90°. The first heat dissipation film is a modified artificial graphite film with a thermal conductivity of [missing information]. The second heat dissipation film is a modified graphene composite graphite film with a thermal conductivity of [missing information]. .
[0012] The nano-silica-polyacrylate composite modifier is grafted with bisphenol A type epoxy resin using silane coupling agent KH-560. The grafting efficiency is determined according to GB / T 41928 standard. When the grafting efficiency is ≥35%, the resin coating rate of the fiber is ≥80%.
[0013] This invention also discloses a method for preparing the above-mentioned high heat dissipation composite functional material for 3C products, comprising the following steps: Step 1: Prepreg Preparation Carbon fiber filaments and glass fiber filaments are selected at a weight ratio of 3:1, electrostatically spread, and then double-sided composite resin film is applied. Dry hot pressing is used at a temperature of 80℃-120℃, a pressure of 2MPa-5MPa, and a time of 30s-60s to produce composite prepreg. The thickness of the prepreg is controlled to be 100μm-150μm. Preparation of the double-sided composite resin film: Bisphenol A type epoxy resin, curing agent, and accelerator are mixed in a weight ratio of 100:10-20:1-3, and 1wt%-3wt% nano silica-polyacrylate composite modifier is added. After stirring evenly, the mixture is coated onto release paper using a casting machine. The drying temperature is 60℃-80℃ and the drying time is 1h-2h. Step 2: Modification of the heat dissipation film Select a 0.1mm-0.3mm thick artificial graphite film or graphene composite graphite film, and use laser drilling at a power of 20W-30W and a frequency of 1kHz-5kHz to process through holes. Then, immerse the heat dissipation film in a silane coupling agent aqueous solution for 10min-30min, remove it, and dry it at 80℃-120℃ for 1h-2h to form a modified heat dissipation film; the concentration of the silane coupling agent aqueous solution is 1wt%-3wt%. Step 3: Lay-up and hot pressing Lay the composite material layer in the following order: first composite material layer → first heat dissipation film → second composite material layer → second heat dissipation film → third composite material layer. Control the fiber orientation angle of each composite material layer to be 45°-90°. Place the material in a hot press mold and use a four-stage gradient heating method: room temperature → 100°C, heating rate 5°C / min, hold for 10 min → 120°C, heating rate 3°C / min, hold for 20 min → 150°C, heating rate 2°C / min, hold for 30 min → 180°C, heating rate 1°C / min, hold for 20 min. The pressure is 5MPa-15MPa, and the cooling rate is ≤5°C / min. Demold the material after cooling to room temperature. Step 4: Post-processing After molding, the composite functional material is trimmed at the edges and polished on the surface to a roughness Ra≤0.8μm. It is then ultrasonically cleaned at a frequency of 40kHz-80kHz for 10min-20min. After drying, its performance is tested to ensure that the product thickness is controlled within 0.3mm-0.5mm.
[0014] In step 1, the preparation of the nano-silica-polyacrylate composite modifier includes: dispersing nano-silica in an ethanol aqueous solution, adding silane coupling agent KH-560, reacting at 70℃-80℃ for 2h-3h, then adding acrylate monomer and initiator azobisisobutyronitrile, polymerizing at 60℃-70℃ for 1h-2h, and obtaining the nano-silica-polyacrylate composite modifier after filtration and drying. In step 3, the hot pressing mold is a silicon nitride coated mold with a temperature uniformity error of ≤±2℃, ensuring that the resin curing degree is ≥98% and the residual stress is ≤2MPa.
[0015] The beneficial effects of this invention are: This invention constructs a three-dimensional technology matrix of resin modification-fiber composite-heat dissipation structure, which solves the problems of thermal response rate, high rigidity, high toughness and strong interfacial bonding through the synergistic effect of the three.
[0016] This invention employs a proprietary system of bisphenol A type epoxy resin and nano-silica-polyacrylate composite modifier. Through the synergistic effect of inorganic nano-reinforcement and organic segment toughening, the thermal conductivity of the resin is increased to a certain level. The elongation at break increased from 4.5% to 5.6%, and it also formed a chemical bridge with the silane coupling agent, strengthening the interfacial bonding.
[0017] This invention determines the optimal weight ratio of carbon fiber to glass fiber (3:1), and combines it with 0° / 90° / 0° gradient layup to form a rigid-tough-rigid mechanical support frame with a flexural strength ≥380MPa and impact resistance. .
[0018] This invention employs a heat dissipation film with 1-3% through holes, which, in conjunction with nano-modified epoxy resin, reduces thermal conductivity resistance, achieving a thermal response rate ≥4℃ / min and a temperature ≤85℃ at 3W power within 10 minutes.
[0019] This invention employs a four-stage gradient hot pressing process to ensure resin curing degree ≥98%, residual stress ≤2MPa, adaptability to existing production lines, equipment modification investment ≤300,000 yuan, and yield rate increased to 92%. Attached Figure Description
[0020] Figure 1 This is an exploded view of the composite functional material structure of Example 1.
[0021] Figure 2 This is a schematic diagram of the composite functional material used for the back cover of a folding mobile phone in Example 1.
[0022] Figure 3 This is a comparison chart of the temperature rise of the composite functional material used for the back cover of the folding mobile phone in Example 1 and a 0.5mm pure carbon plate.
[0023] Figure 4 This is a thermal imaging comparison of the composite functional material used for the back cover of the folding phone in Example 1 and a 0.5mm pure carbon plate after 30 minutes of temperature rise. Detailed Implementation
[0024] The parameters and sources of some raw materials in the examples are as follows: Bisphenol A type epoxy resin, model E51, epoxy value 0.51-0.54 eq / 100g.
[0025] This is a nano-silica-polyacrylate composite modifier with a grafting rate of 35%. It refers to a core-shell structure modifier grafted using the silane coupling agent KH-560. The core consists of nano-silica with a particle size of 10nm-30nm, and the shell is polyacrylate segments. The grafting rate is determined according to the group standard LX SDAMA 0006-2023, "Determination of Grafting Rate of Modified Inorganic Powder Materials - Thermogravimetric Method". Grafting efficiency refers to the proportion of polyacrylate segments successfully grafted onto the surface of nano-silica, determined by a combination of infrared spectroscopy and thermogravimetric analysis.
[0026] The preparation of the nano-silica-polyacrylate composite modifier includes: dispersing 1 part by weight of nano-silica in 9 parts by weight of an ethanol aqueous solution; adding silane coupling agent KH-560, the amount of silane coupling agent added being 0.5 wt% of the nano-silica; reacting at 70°C for 3 h; then adding acrylate monomer and initiator azobisisobutyronitrile; polymerizing at 70°C for 2 h; and obtaining the nano-silica-polyacrylate composite modifier after filtration and drying. The concentration of the ethanol aqueous solution is 10 wt%. The acrylate monomer is methyl acrylate.
[0027] Artificial graphite film, thermal conductivity of XY plane ,density It originates from Jiangxi Desien New Materials Co., Ltd.
[0028] Graphene composite graphite film, thermal conductivity of XY plane ,density It originates from Jiangxi Desien New Materials Co., Ltd. Example 1
[0029] The composition of the composite functional material used for the back cover of foldable phones is as follows: From top to bottom, such as Figure 1 As shown, they are in the following order: First composite material layer: carbon fiber-glass fiber composite prepreg, carbon fiber:glass fiber weight ratio 3:1, resin content accounts for 40wt% of the total weight of the first composite material layer, thickness 100μm, layup angle 0°; First heat dissipation film: Modified artificial graphite film, 0.1mm thick, 0.5mm pore diameter, circular holes, 2mm hole spacing, through holes accounting for approximately 2%, KH-550 coating, thermal conductivity... ; Second composite material layer: carbon fiber-glass fiber composite prepreg, carbon fiber:glass fiber weight ratio 3:1, resin content accounts for 35wt% of the total weight, thickness 100μm, layup angle 90°; Second heat dissipation film: Modified graphene composite graphite film, 0.1mm thick, 0.3mm pore diameter, circular holes, 1.5mm hole spacing, through holes accounting for approximately 2%, KH-560 coating, thermal conductivity... ; The third composite material layer is a carbon fiber-glass fiber composite prepreg with a carbon fiber to glass fiber weight ratio of 3:1, a resin content of 45 wt% of the total weight, a thickness of 100 μm, and a layup angle of 0°.
[0030] The resin, specifically a double-sided composite resin film, is composed of 81 wt% bisphenol A type epoxy resin, 2 wt% nano silica-polyacrylate composite modifier, 15 wt% curing agent, and 2 wt% accelerator, with a thermal conductivity of... The curing agent is diaminodiphenylmethane; the accelerator is 2-methylimidazole. Preparation method: Bisphenol A type epoxy resin, curing agent, and accelerator are mixed, and a nano-silica-polyacrylate composite modifier is added. After stirring evenly, the mixture is coated onto release paper using a casting machine. The drying temperature is 70℃, and the drying time is 2 hours.
[0031] The preparation method of the composite functional material for the back cover of the folding mobile phone mentioned above includes the following steps: Step 1: Prepreg preparation: Take carbon fiber filaments and glass fiber filaments, and electrostatically spread them with an 8kV voltage; dry hot press the carbon fiber filaments, glass fiber filaments and double-sided composite resin film at a temperature of 100℃, a pressure of 3MPa and a time of 45s to make a composite prepreg, and control the thickness of the prepreg to be 100μm. Step 2: Modification of the heat dissipation film: A 0.1 mm thick artificial graphite film was selected and perforated using a laser at 20 W and 3 kHz to create through holes. The heat dissipation film was then immersed in a silane coupling agent aqueous solution for 20 min, and then dried at 100 °C for 2 h to form the first heat dissipation film. A 0.1 mm thick graphene composite graphite film was also selected and perforated using a laser at 20 W and 3 kHz to create through holes. The heat dissipation film was then immersed in a silane coupling agent aqueous solution for 20 min, and then dried at 100 °C for 2 h to form the second heat dissipation film. The concentration of the silane coupling agent aqueous solution was 2 wt% in both cases. Step 3: Laying up and hot pressing: Lay up the composite material layer in the following order: first composite material layer → first heat dissipation film → second composite material layer → second heat dissipation film → third composite material layer. Control the fiber orientation angle of each composite material layer to be 90°. Place the layer in a hot press mold and use a four-stage gradient heating method: room temperature → 100℃, heating rate 5℃ / min, hold for 10min → 120℃, heating rate 3℃ / min, hold for 20min → 150℃, heating rate 2℃ / min, hold for 30min → 180℃, heating rate 1℃ / min, hold for 20min. The pressure is 10MPa, and the cooling rate is ≤5℃ / min. Demold after cooling to room temperature. Step 4 Post-processing: Trim the edges of the molded composite functional material and grind the surface to a roughness Ra=0.6μm; ultrasonically clean at a frequency of 60kHz for 15min and a drying temperature of 80℃; test the performance after drying to ensure that the product thickness is controlled within 0.5mm.
[0032] Table 1 Performance test results of composite functional materials used in the back cover of folding mobile phones in Example 1
[0033] Thermal response rate: refers to the average rate at which the surface temperature of a material rises from its initial temperature to its thermal equilibrium temperature under a 3W analog chip power. The test method refers to GB / T 22588-2008 "Measuring thermal diffusivity or thermal conductivity by flash method". Delamination rate: refers to the proportion of the interlayer separation area to the total surface area after the material has undergone 100,000 180° bends (bending radius 2mm).
[0034] Table 2 Comparison of performance tests with existing materials
[0035] Comparative Example 1 It is basically the same as Example 1, except that 2wt% nano silica-polyacrylate composite modifier (grafting rate 35%) is replaced with 2wt% nano silica.
[0036] Comparative Example 2 The process is basically the same as in Example 1, except that the carbon fiber-glass fiber composite prepreg (weight ratio 3:1) in the first composite material layer, the second composite material layer, and the third composite material layer is replaced with carbon fiber-glass fiber composite prepreg (weight ratio 2:1).
[0037] Comparative Example 3 It is basically the same as Example 1, except that the proportion of through holes in the first heat dissipation film and the second heat dissipation film is replaced by 1% instead of 2%.
[0038] Comparative Example 4 It is basically the same as Example 1, except that the hot pressing process is replaced by the traditional two-stage hot pressing process.
[0039] The traditional two-stage hot pressing process is as follows.
[0040] Table 3 Performance test results of comparative composite functional materials
[0041] The thermal response rate of this invention is ≥5.2℃ / min, which is more than 3 times higher than that of existing materials, solving the performance throttling problem caused by instantaneous heat generation in 3C product chips; bending strength is ≥380MPa, and impact resistance is ≥380MPa. Interlaminar shear strength ≥28MPa, meeting the requirement of 100,000 bends without peeling for folded products; density It is 44% lighter than ceramic cover plates and 9% lighter than pure carbon fiber cover plates, which is in line with the trend of thinner and lighter 3C products.
[0042] Table 4. Comparison of temperature rise between 0.5mm pure carbon steel plate and composite functional materials used in the back cover of folding mobile phones (°C)
[0043] As shown in Table 4 and Figure 3 It is evident that the composite functional material for the folding mobile phone back cover of the present invention has a good heat dissipation effect.
[0044] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.
Claims
1. A high heat dissipation composite functional material for 3C products, characterized in that: It includes at least two composite material layers and at least one heat dissipation film, wherein the heat dissipation film is sandwiched between adjacent composite material layers to form a sandwich-type stacked structure of composite material layer-heat dissipation film-composite material layer.
2. The high heat dissipation composite functional material for 3C products as described in claim 1, characterized in that: The composite material layer is made of carbon fiber and glass fiber in a weight ratio of 3:1 and is pressed together. The layup angle of each composite material layer is at least two combinations of 0°, 45° and 90°. The fiber mass fraction is 50%-70% and the balance is resin.
3. The high heat dissipation composite functional material for 3C products as described in claim 1, characterized in that: The heat dissipation film is a modified graphene composite graphite film or a modified artificial graphite film with a thickness of 0.1mm-0.3mm. The surface is uniformly distributed with through holes with a diameter of 0.3mm-0.5mm and a spacing of 1.5mm-2mm. The total area of the through holes accounts for 1-3% of the surface area of the heat dissipation film. The inner wall of the through holes is coated with a silane coupling agent layer with a thickness of 0.001mm-0.005mm. The silane coupling agent is KH-550 or KH-560.
4. The high heat dissipation composite functional material for 3C products as described in claim 2, characterized in that: The resin is composed of 1wt%-3wt% nano silica-polyacrylate composite modifier, 10wt%-20wt% curing agent, 1wt%-3wt% accelerator and the balance bisphenol A type epoxy resin.
5. The high heat dissipation composite functional material for 3C products as described in claim 4, characterized in that: The nano-silica-polyacrylate composite modifier has a core-shell structure, with a core particle size of 10nm-30nm and a shell composed of polyacrylate segments with a grafting rate of ≥30%; the resin has a low thermal conductivity. The curing agent is diaminodiphenylmethane; the accelerator is 2-methylimidazole.
6. The high heat dissipation composite functional material for 3C products as described in claim 2, characterized in that: The density of the composite functional material is Flexural strength ≥380MPa, interlaminar shear strength ≥28MPa, impact strength Under 3W analog chip power, the surface temperature is ≤85℃ within 10 minutes, the thermal response rate is ≥4℃ / min, and the interlayer peeling rate is ≤5% after 100,000 bending cycles.
7. The high heat dissipation composite functional material for 3C products as described in claim 1, characterized in that: It is prepared by integral molding through hot pressing, which adopts a four-stage gradient heating method.
8. The high heat dissipation composite functional material for 3C products as described in claim 1, characterized in that: The high heat dissipation composite material for 3C products includes a first composite material layer, a second composite material layer, and a third composite material layer. A first heat dissipation film is provided between the first composite material layer and the second composite material layer, and a second heat dissipation film is provided between the second composite material layer and the third composite material layer. The layup angle of the first composite material layer is 0°, the layup angle of the second composite material layer is 45°, and the layup angle of the third composite material layer is 90°.
9. The high heat dissipation composite functional material for 3C products as described in claim 8, characterized in that: The first heat dissipation film is a modified artificial graphite film with a thermal conductivity of [missing information]. The second heat dissipation film is a modified graphene composite graphite film with a thermal conductivity of [missing information]. The through holes in the heat dissipation film are hexagonal or circular.
10. The method for preparing a high heat dissipation composite functional material for 3C products as described in any one of claims 8-9, characterized in that, Includes the following steps: Step 1: Prepreg Preparation Carbon fiber filaments and glass fiber filaments are selected at a weight ratio of 3:1, electrostatically spread, and then double-sided composite resin film is applied. Dry hot pressing is used at a temperature of 80℃-120℃, a pressure of 2MPa-5MPa, and a time of 30s-60s to produce composite prepreg. The thickness of the prepreg is controlled to be 100μm-150μm. Preparation of the double-sided composite resin film: Bisphenol A type epoxy resin, curing agent, and accelerator are mixed in a weight ratio of 100:10-20:1-3, and 1wt%-3wt% nano silica-polyacrylate composite modifier is added. After stirring evenly, the mixture is coated onto release paper using a casting machine. The drying temperature is 60℃-80℃ and the drying time is 1h-2h. Step 2: Modification of the heat dissipation film Select a 0.1mm-0.3mm thick artificial graphite film or graphene composite graphite film, and use laser drilling at a power of 20W-30W and a frequency of 1kHz-5kHz to process through holes. Then, immerse the heat dissipation film in a silane coupling agent aqueous solution for 10min-30min, remove it, and dry it at 80℃-120℃ for 1h-2h to form a modified heat dissipation film; the concentration of the silane coupling agent aqueous solution is 1wt%-3wt%. Step 3: Lay-up and hot pressing Lay the composite material layer in the following order: first composite material layer → first heat dissipation film → second composite material layer → second heat dissipation film → third composite material layer. Control the fiber orientation angle of each composite material layer to be 45°-90°. Place the material in a hot press mold and use a four-stage gradient heating method: room temperature → 100°C, heating rate 5°C / min, hold for 10 min → 120°C, heating rate 3°C / min, hold for 20 min → 150°C, heating rate 2°C / min, hold for 30 min → 180°C, heating rate 1°C / min, hold for 20 min. The pressure is 5MPa-15MPa, and the cooling rate is ≤5°C / min. Demold the material after cooling to room temperature. Step 4: Post-processing After molding, the composite functional material is trimmed at the edges and polished on the surface to a roughness Ra≤0.8μm. It is then ultrasonically cleaned at a frequency of 40kHz-80kHz for 10min-20min. After drying, its performance is tested to ensure that the product thickness is controlled within 0.3mm-0.5mm. In step 1, the preparation of the nano-silica-polyacrylate composite modifier includes: dispersing nano-silica in an ethanol aqueous solution, adding silane coupling agent KH-560, reacting at 70℃-80℃ for 2h-3h, then adding acrylate monomer and initiator azobisisobutyronitrile, polymerizing at 60℃-70℃ for 1h-2h, and obtaining the core-shell structure composite modifier after filtration and drying. In step 3, the hot pressing mold is a silicon nitride coated mold with a temperature uniformity error of ≤±2℃, ensuring that the resin curing degree is ≥98% and the residual stress is ≤2MPa.