Carbon fiber heat-conducting gasket with insulating function and preparation method of carbon fiber heat-conducting gasket

Abstract

The invention relates to the technical field of heat conduction gaskets, in particular to a carbon fiber heat conduction gasket with an insulation function and a preparation method of the carbon fiber heat conduction gasket. The carbon fiber heat conduction gasket is of a five-layer structure which sequentially comprises a rhombic pattern film layer, an insulating layer, a carbon fiber heat conduction silica gel layer, an insulating layer and a rhombic pattern film layer. The carbon fiber heat conduction gasket with the insulation function has obvious technical advantages, the design thought of carbon fiber orientation and surface insulation is adopted, C-H bonds on the surfaces of the carbon fibers have high binding force with silicon rubber, the vertically-oriented carbon fibers have excellent heat conduction characteristics, and the silicon carbide insulation layer at the top ends of the carbon fibers has an insulation effect. The carbon fiber heat conduction gasket with the insulation function has the advantages of high heat conduction performance, high insulation performance, high flexibility, high reliability, convenient on-site construction and high batch operation consistency, and overcomes the defect of poor insulation performance of other carbon fiber heat conduction gaskets.

Description

Technical Field

[0001] The present invention relates to the technical field of thermally conductive pads, and more specifically to a carbon fiber thermally conductive pad with insulating function and a preparation method thereof. Background Art

[0002] As third-generation semiconductor silicon-based chips such as gallium nitride (GaN) and silicon carbide (SiC) develop towards innovative three-dimensional chip stacking technology, the progress of processes and new materials has improved the performance of silicon-based chips. Chips generate a lot of heat when working. The heat dissipation problem will affect the reliability, stability and service life of electronic equipment during use. In order to control the operating temperature of the chip, ensuring effective heat transfer from the chip to the heat sink is a key step in solving this challenge. From 5G base stations, ultra-fast charging stations to consumer electronics, improving the thermal conductivity of the thermally conductive insulating pad between the chip and the heat sink has become a topic that must be faced by product manufacturers.

[0003] At present, the thermal insulation pads on the market include ceramic filled thermal pads, graphene filled thermal pads, and carbon fiber filled thermal pads, which can solve the heat dissipation problem of electronic chips. Among them, carbon fiber filled thermal pads have high thermal conductivity in the Z axis, with thermal conductivity up to 1200W / m·K. Therefore, how to make the carbon fiber vertically oriented and distributed in the thermal pad and improve its insulation performance is the focus of research.

[0004] In the prior art, Kojiro Uetan et al. achieved high orientation of carbon fibers through electrostatic flocking. By applying an external electric field, the conductive filler was oriented along the direction of the electric field. When the carbon fiber filling amount was 13.2wt%, the thermal conductivity could reach 21W / m·K, and it had a certain degree of softness. However, the filling amount of the gasket filler prepared by this method is uncontrollable, and the orientation of the filler is not unique, and the insulation of the gasket is poor.

[0005] At present, there is no report on the preparation of carbon fiber thermal conductive pad products with insulating properties by roller pressing. This type of product is mainly produced through the processes of calendering on a three-roll mill, cutting by a cutting machine, multi-layer lamination, cutting, etc. It has high thermal conductivity and electrical insulation properties, can be mass-produced by machine, and avoids the problem of decreased thermal conductivity of traditional carbon fiber after compression.

[0006] In the prior art, the carbon fiber thermal conductive pad can only reach 30W / m·K. Since carbon fiber is added to the polymer, the material only has thermal conductivity but no insulation function. For example, the Chinese invention patent publication number is CN112143037A, and its name is a surface insulation modified carbon fiber filler and a thermal conductive insulating material prepared therefrom. The carbon fiber thermal conductive pad is a randomly arranged carbon fiber with low thermal conductivity and low breakdown voltage. The carbon fiber is immersed in a pH 4-6 aniline phosphate buffer for electroplating to form a polyaniline insulating layer on the surface of the carbon fiber, and then stirred evenly with an inorganic thermal conductive filler, a curing agent, and an additive under vacuum conditions, and subjected to pulse vibration, heating and curing to obtain a thermal conductive insulating pad with a thermal conductivity of 11W / m·K and a breakdown strength of 200V / mm. For example, the Chinese invention patent publication number is CN116769195A, and the name is a carbon fiber thermal conductive pad and its preparation method, wherein the carbon fiber thermal conductive pad is an oriented carbon fiber, and the carbon fibers arranged in the same direction are immersed in a polymer matrix, and a composite material is obtained by cross-linking and curing, and cut into thermal conductive pads along the axial direction perpendicular to the carbon fibers, with a thermal conductivity of 43W / m·K and a breakdown strength of only 100V / mm. Although the prepared carbon fiber thermal conductive pad has a high thermal conductivity, its breakdown strength is very low and it is easy to short-circuit. The lack of coupling agent treatment and surface insulation in the process leads to a weak bonding force between the carbon fiber and the silica gel, which is easy to split when cut. Summary of the invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one aspect of the present invention is to provide a carbon fiber thermal conductive pad with an insulating function, wherein the carbon fiber thermal conductive pad has a five-layer structure, which is a diamond pattern film layer, an insulating layer, a carbon fiber thermal conductive silicone layer, an insulating layer and a diamond pattern film layer in sequence.

[0008] Preferably, the diamond pattern film layer has a thickness of 0.05 mm to 0.1 mm, the insulation layer has a thickness of 0.01 mm to 0.03 mm, and the carbon fiber thermal conductive silicone layer has a thickness of 10 μm to 15 μm.

[0009] Preferably, the diamond pattern film layer is made of PE.

[0010] Preferably, the insulating layer is a silicon carbide film layer.

[0011] Preferably, the raw materials of the carbon fiber thermal conductive silicone layer include graphene carbon fiber, phenyl vinyl silicone resin, vinyl silicone oil, hydrogen-containing silicone oil and platinum catalyst.

[0012] Preferably, the raw material ratio of the carbon fiber thermal conductive silicone layer is 20 to 40 parts of graphene carbon fiber, 40 to 70 parts of phenyl vinyl silicone resin, 10 to 20 parts of vinyl silicone oil, 3 to 6 parts of hydrogenated silicone oil and 1 to 3 parts of platinum catalyst.

[0013] Preferably, the thermal conductivity of the graphene carbon fiber is 900W / mK~1200W / mK, the length is 200mm~300mm, and the single filament diameter is 13μm~20μm; the viscosity of the phenyl vinyl silicone resin at a temperature of 25°C is 100mPa·s~200mPa·s; the viscosity of the vinyl silicone oil at a temperature of 25°C is 100mPa·s~200mPa·s; the hydrogen content of the hydrogen-containing silicone oil is 0.08%~0.18%; the activity of the platinum catalyst is 4000ppm~5000ppm; the particle size of the silicon carbide is 10μm~20μm.

[0014] Another aspect of the present invention is to provide a method for preparing a carbon fiber thermal conductive pad with an insulating function, wherein the specific steps of the preparation method are as follows: S1. Arrange the graphene carbon fibers at equal intervals on both sides of the rectangular plate; S2. Coupling treatment: soaking the graphene carbon fiber arranged in S1 in a silane coupling agent solution, and drying after soaking to obtain a carbon fiber sheet; S3. Oriented alignment: The carbon fiber sheet prepared in S3 is placed vertically in a closed container; S4. Glue injection: inject the mixed phenyl vinyl silicone resin, vinyl silicone oil, hydrogen silicone oil and platinum catalyst from the top of the closed container; S5. Heating and curing: placing the sealed container filled with glue in an oven for heating, and taking out the cured carbon fiber silicone block after completion; S6. Cutting: Cutting the carbon fiber silicone block prepared in S5 into carbon fiber silicone sheets; S7. Surface insulation: A layer of air permeable holes is attached to the surface of the carbon fiber silicone sheet prepared in S6, and a silicon carbide acrylic insulating film layer is sprayed on the surface, and then dried to form an insulating layer to achieve an insulating effect; S8. Laminating: Laminating the upper and lower insulating layers prepared in S7 to form a diamond pattern film layer for protection.

[0015] Preferably, the length of the graphene carbon fiber in S1 is 200mm-300mm, and the spacing is 50μm-80μm; the silane coupling agent component in S2 is a mixed solution of KH550, KH560 and ethanol, the ratio of KH550, KH560 to ethanol is (1-2): (2-4): (70-140), the immersion time is 2h-4h, and after immersion, it is dried at 120℃-140℃ for 5min-10min; the spacing of the carbon fiber plates in S3 is 10mm-50mm; the material ratio in S1 and S4 is 20-40 parts of graphene carbon fiber, 40-70 parts of phenyl vinyl silicone resin, 10-20 parts of vinyl silicone oil, 3-6 parts of hydrogenated silicone oil and 1-3 parts of platinum catalyst.

[0016] Preferably, in S5, the heating temperature is 120℃~140℃, and the heating time is 1h~2h; in S6, the carbon fiber silicone block is cut into carbon fiber silicone sheets of different thicknesses according to the thickness of 0.5mm, 1.0mm, 1.5mm, and 2.0mm as the spacing; in S7, the diameter of the air holes is 0.5mm~1mm, the spacing is 0.5mm, the drying temperature is 120℃~140℃, and the time is 5min~10min; in S8, the coating is a PE diamond pattern film.

[0017] The beneficial effects of the present invention are as follows: Compared with the prior art, the carbon fiber thermal conductive pad with insulation function prepared by the present invention has obvious technical advantages. It adopts the design concept of carbon fiber orientation + surface insulation. The CH bond on the surface of the carbon fiber has a strong bonding force with the silicone rubber. The vertically oriented carbon fiber has excellent thermal conductivity. The silicon carbide insulation layer on the top of the carbon fiber plays an insulating role. The main performance indicators of the carbon fiber thermal conductive pad with insulation function prepared by the present invention are thermal conductivity ≥10W / m·K~40W / m·K, volume resistivity ≥10 10 Ωcm, breakdown voltage ≥2000Vac / mm, hardness: 40-50 (shore 00). The carbon fiber thermal conductive pad with insulation function prepared by the present application has high thermal conductivity, high insulation, high softness, high reliability, convenient on-site construction, high batch operation consistency, and makes up for the shortcomings of poor insulation performance of other carbon fiber thermal conductive pads. The carbon fiber thermal conductive pad with insulation function prepared by the present application is conducive to close fitting, filling gaps, reducing thermal resistance, and extending the service life of the heating chip.

[0018] Additional aspects and advantages of the invention will become apparent from the following description, or may be learned by practice of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 This is a structural diagram of a carbon fiber thermal conductive pad with insulation function prepared in an embodiment of the present invention; Figure 2 This is a schematic diagram of wiring steps in Embodiment 1 of the present invention; Figure 3 1 is a schematic diagram of the coupling treatment steps of Example 1 of the present invention; Figure 4 It is a schematic diagram of a certain directional arrangement step of an embodiment of the present invention; Figure 5 This is a schematic diagram of the glue injection steps in the first embodiment of the present invention; Figure 6 This is a schematic diagram of the heating and curing step of Embodiment 1 of the present invention; Figure 7 is a schematic diagram of cutting steps in Embodiment 1 of the present invention; Figure 8 is a schematic diagram of a surface insulation step in Embodiment 1 of the present invention; Fig. 9 is a schematic diagram of the laminating step in the first embodiment of the present invention; in, Figure 1 and Fig. 9 The corresponding relationship between the reference numerals and the component names is as follows: 1 is a diamond pattern film layer, 2 is an insulating layer, 3 is a carbon fiber thermal conductive silicone layer, 4 is a graphene carbon fiber, and 5 is. DETAILED DESCRIPTION

[0020] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from the description. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0022] Embodiment 1 S1. Weigh 50g of graphene carbon fiber, 200mm in length, 13μm in diameter, and 80μm in fiber spacing. Arrange the graphene carbon fiber at equal intervals on both sides of the rectangular plate and fix it. Make 20 plates in sequence. Figure 2 As shown; S2. Soak the arranged graphene carbon fiber in a silane coupling agent solution, the silane coupling agent is a mixed solution of 3g KH550, 5g KH560 and 300g ethanol, the soaking time is 2h-4h, and then dry at 140℃ for 10min. Figure 3 As shown; S3. Place the fiberboard after coupling treatment vertically in a closed container with a distance of 50 mm between the fiberboards. Figure 4 As shown; S4. From the top of the closed container, inject the mixed 100g phenyl vinyl silicone resin (viscosity at 25°C is 200mPa·s), 30g vinyl silicone oil (viscosity at 25°C is 200mPa·s), 8g hydrogenated silicone oil (hydrogen content is 0.18%) and 4g platinum catalyst (activity is 5000ppm), as follows: Figure 5 As shown; S5. Place the container filled with glue in an oven, heat to 140°C for 1 hour, and take out the cured carbon fiber silicone block. Figure 6 As shown; S6. Cut the carbon fiber silicone block into carbon fiber silicone sheets of different thicknesses at intervals of 1.0 mm, such as Figure 7 As shown; S7. A layer of 0.5mm diameter and 50mm spacing air holes is attached to the surface of a 1.0mm thick carbon fiber silicone sheet, and 3g of silicon carbide acrylic insulation film coating is sprayed on it at 120℃ and dried for 10min. The film thickness is 10μm, which has an insulating effect. The air holes are removed, such as Figure 8 As shown; S8. Cover the carbon fiber thermal conductive silicone sheet with silicon carbide insulation layer with release film on the top and bottom, with a thickness of 0.1mm, to play a protective role. Fig. 9 shown.

[0023] Embodiment 2 S1. Weigh 70g of graphene carbon fiber, 250mm in length, 16μm in diameter, and 60μm in fiber spacing, arrange the graphene carbon fibers at equal intervals on both sides of the rectangular plate, fix them, and make 20 plates in sequence; S2. Soak the arranged graphene carbon fiber in a silane coupling agent solution, wherein the silane coupling agent is a mixed solution of 4gKH550, 6gKH560 and 330g ethanol, and the soaking time is 2h-4h. After soaking, dry at 140°C for 10min; S3. The fiberboard after coupling treatment is placed vertically in a closed container with a spacing of 40 mm between the fiberboards; S4. From the top of the closed container, 90 g of phenyl vinyl silicone resin (viscosity of 200 mPa·s at 25 ° C), 25 g of vinyl silicone oil (viscosity of 200 mPa·s at 25 ° C), 6 g of hydrogenated silicone oil (hydrogen content of 0.18%) and 3 g of platinum catalyst (activity of 5000 ppm) were injected into the mixture; S5. Place the container filled with glue in an oven, heat to 130°C for 1.5h, and take out the cured carbon fiber silicone block; S6. Cut the carbon fiber silicone block into carbon fiber silicone sheets of different thicknesses at a pitch of 0.5 mm; S7. A layer of air holes with a diameter of 0.5 mm and a spacing of 40 mm is attached to the surface of a 0.5 mm thick carbon fiber silicone sheet, and 3.5 g of silicon carbide acrylic insulating film coating is sprayed on the surface of the sheet at 130 ° C. The film is dried for 10 min and the film thickness is 10 μm to achieve an insulating effect. The air holes are removed. S8. Cover the carbon fiber thermal conductive silicone sheet with silicon carbide insulation layer with release film on the top and bottom, with a thickness of 0.1mm, to play a protective role. Embodiment 3 S1. Weigh 90g of graphene carbon fiber, 300mm in length, 20μm in diameter, and 40μm in fiber spacing. Arrange the graphene carbon fibers at equal intervals on both sides of the rectangular plate, fix them, and make 20 plates in sequence; S2. Soak the arranged graphene carbon fiber in a silane coupling agent solution, wherein the silane coupling agent is a mixed solution of 5gKH550, 8gKH560 and 350g ethanol, the soaking time is 4h, and after soaking, it is dried at 140°C for 10min; S3. The fiberboard after coupling treatment is placed vertically in a closed container with a spacing of 30 mm between the fiberboards; S4. From the top of the closed container, 100 g of phenyl vinyl silicone resin (viscosity at 25 ° C is 200 mPa s), 30 g of vinyl silicone oil (viscosity at 25 ° C is 200 mPa s), 8 g of hydrogenated silicone oil (hydrogen content is 0.18%) and 5 g of platinum catalyst (activity is 5000 ppm) were injected into the mixture; S5. Place the container filled with glue in an oven, heat to 120°C for 2h, and take out the cured carbon fiber silicone block; S6. Cut the carbon fiber silicone block into carbon fiber silicone sheets of different thicknesses at a pitch of 1.5 mm; S7. A layer of 0.5mm diameter and 30mm spacing air holes is attached to the surface of a 1.5mm thick carbon fiber silicone sheet, and 4g of silicon carbide acrylic insulating film coating is sprayed on the surface, the temperature is 140°C, and the drying time is 10min. The film thickness is 10μm, which has an insulating effect, and the air holes are removed; S8. Cover the carbon fiber thermal conductive silicone sheet with silicon carbide insulation layer with release film on the top and bottom, with a thickness of 0.1mm, to play a protective role. In order to verify the performance of the carbon fiber thermal conductive insulating pad prepared by the present invention, the following tests were performed: Thermal conductivity test The carbon fiber thermal conductive insulating pads prepared in Examples 1 to 3 were made into square samples with sizes of 26 mm × 26 mm × 0.5 mm, 26 mm × 26 mm × 1.0 mm, and 26 mm × 26 mm × 1.5 mm, and placed on the test table of a LW9389 thermal conductivity tester. The thermal resistance values ​​at different thicknesses were measured, and the thermal conductivity was fitted. The test results are shown in Table 1 below.

[0024] Volume resistivity test The carbon fiber thermal conductive insulating pads prepared in Examples 1 to 3 were made into square samples with a size of 100 mm × 100 mm × 3 mm, and their volume resistivity was tested in accordance with GB / T 31838.2-2019 standard. The test results are shown in Table 1 below.

[0025] Breakdown voltage test The carbon fiber thermal conductive insulating pads prepared in Examples 1 to 3 were made into square samples with a size of 100 mm×100 mm×1 mm, placed on the test table of a KZT type power frequency withstand voltage tester, and tested for breakdown voltage. The results are shown in Table 1 below.

[0026] Hardness test The carbon fiber thermal conductive insulating pads prepared in Examples 1 to 3 were made into square samples with a size of 50 mm×50 mm×6 mm, placed on the test table of a Shore 00 hardness tester, and tested for hardness. The results are shown in Table 1 below.

[0027] Table 1. Carbon fiber thermal insulation pad performance test results In summary, the carbon fiber thermal conductive pad with insulation function prepared by the present invention has a thermal conductivity of up to 40.3 W / mK and a volume resistivity of 2.1×10 10Ωcm, breakdown voltage 2000Vac / mm, better solves the high thermal conductivity and high insulation compatibility problems, and is the best solution for products on the market. At the same time, the present invention can achieve thermal conductivity of 10W / mK-40W / mK and volume resistivity of 4.5×10 10 Ωcm-2.1×10 10 Ωcm dynamically adjustable design can meet the user's requirements in different application scenarios.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may also have various modifications and variations. 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 carbon fiber thermal conductive pad with insulation function, characterized in that: The carbon fiber thermal conductive pad has a five-layer structure, which is a diamond pattern film layer, an insulating layer, a carbon fiber thermal conductive silicone layer, an insulating layer and a diamond pattern film layer in sequence.

2. The carbon fiber thermal conductive pad with insulation function according to claim 1, characterized in that: The thickness of the diamond pattern film layer is 0.05 mm to 0.1 mm, the thickness of the insulation layer is 0.01 mm to 0.03 mm, and the thickness of the carbon fiber thermal conductive silicone layer is 10 μm to 15 μm.

3. The carbon fiber thermal conductive pad with insulation function according to claim 1, characterized in that: The material of the diamond pattern film layer is PE.

4. The carbon fiber thermal conductive pad with insulation function according to claim 1, characterized in that: The insulating layer is a silicon carbide film layer.

5. The carbon fiber thermal conductive pad with insulation function according to claim 1, characterized in that: The raw materials of the carbon fiber thermal conductive silicone layer include graphene carbon fiber, phenyl vinyl silicone resin, vinyl silicone oil, hydrogen-containing silicone oil and platinum catalyst.

6. The carbon fiber thermal conductive pad with insulation function according to claim 5, characterized in that: The raw material ratio of the carbon fiber thermal conductive silicone layer is 20 to 40 parts of graphene carbon fiber, 40 to 70 parts of phenyl vinyl silicone resin, 10 to 20 parts of vinyl silicone oil, 3 to 6 parts of hydrogen-containing silicone oil and 1 to 3 parts of platinum catalyst.

7. The carbon fiber thermal conductive pad with insulation function according to claim 5 or 6, characterized in that: The thermal conductivity of the graphene carbon fiber is 900W / mK to 1200W / mK, the length is 200mm to 300mm, and the single fiber diameter is 13μm to 20μm; the viscosity of the phenyl vinyl silicone resin at a temperature of 25°C is 100mPa·s to 200mPa·s; the viscosity of the vinyl silicone oil at a temperature of 25°C is 100mPa·s to 200mPa·s; the hydrogen content of the hydrogen-containing silicone oil is 0.08% to 0.18%; the activity of the platinum catalyst is 4000ppm to 5000ppm; and the particle size of the silicon carbide is 10μm to 20μm.

8. The method for preparing a carbon fiber thermal conductive pad with insulation function according to claim 1, characterized in that: The specific steps of the preparation method are as follows: S1. Arrange the graphene carbon fibers at equal intervals on both sides of the rectangular plate; S2. Coupling treatment: soaking the graphene carbon fiber arranged in S1 in a silane coupling agent solution, and drying after soaking to obtain a carbon fiber sheet; S3. Oriented alignment: The carbon fiber sheet prepared in S3 is placed vertically in a closed container; S4. Glue injection: inject the mixed phenyl vinyl silicone resin, vinyl silicone oil, hydrogen silicone oil and platinum catalyst from the top of the closed container; S5. Heating and curing: placing the sealed container filled with glue in an oven for heating, and taking out the cured carbon fiber silicone block after completion; S6. Cutting: Cutting the carbon fiber silicone block prepared in S5 into carbon fiber silicone sheets; S7. Surface insulation: a layer of air permeable holes is attached to the surface of the carbon fiber silicone sheet prepared in S6, and a silicon carbide acrylic insulating film layer is sprayed on the surface, and then dried to form an insulating layer; S8. Laminating: Laminating the upper and lower insulating layers prepared in S7 to form a diamond pattern film layer.

9. The method for preparing a carbon fiber thermal conductive pad with insulation function according to claim 8, characterized in that: The length of the graphene carbon fiber in S1 is 200mm-300mm, and the spacing is 50μm-80μm; the silane coupling agent component in S2 is a mixed solution of KH550, KH560 and ethanol, the ratio of KH550, KH560 to ethanol is (1-2): (2-4): (70-140), the immersion time is 2h-4h, and after immersion, it is dried at 120℃-140℃ for 5min-10min; the spacing of the carbon fiber plates in S3 is 10mm-50mm; the material ratio in S1 and S4 is 20-40 parts of graphene carbon fiber, 40-70 parts of phenyl vinyl silicone resin, 10-20 parts of vinyl silicone oil, 3-6 parts of hydrogen-containing silicone oil and 1-3 parts of platinum catalyst.

10. The method for preparing a carbon fiber thermal conductive pad with insulation function according to claim 8, characterized in that: In S5, the heating temperature is 120℃~140℃, and the heating time is 1h~2h; in S6, the carbon fiber silicone block is cut into carbon fiber silicone sheets of different thicknesses according to the thickness of 0.5mm, 1.0mm, 1.5mm, and 2.0mm. In S7, the diameter of the air holes is 0.5mm~1mm, the spacing is 0.5mm, the drying temperature is 120℃~140℃, and the time is 5min~10min; in S8, the coating is a PE diamond pattern film.

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