Preparation method of coated graphene heat-conducting gasket

Abstract

The embodiment of the invention provides a preparation method of a coated graphene heat-conducting gasket, and relates to the field of graphene application. The preparation method of the coated graphene heat-conducting gasket comprises the following steps: S1, laminating and stacking a graphene sheet on a first polyimide film, wherein the graphene sheet is located in the middle of the first polyimide film; s2, upwards bending the edge, exposed out of the graphene sheet, of the first polyimide film by adopting a bending process until the edge is attached to and covers the side surface and top surface edge parts of the graphene sheet; and S3, laminating and covering a second polyimide film on the middle part of the top surface of the graphene sheet and the first polyimide film above the second polyimide film to form a full-coating structure. The preparation method of the coated graphene heat-conducting gasket is simple in process, and the graphene sheet can be fully coated, so that the heat-conducting gasket has relatively good heat-conducting property and insulating property.

Description

Technical Field

[0001] The present application relates to the field of graphene applications, and in particular, to a method for preparing a coated graphene thermally conductive gasket. Background Art

[0002] Graphene is a carbon atom in the form of sp 2 The thermal conductivity of the single-layer two-dimensional honeycomb lattice structure material formed by the hybrid orbitals can be as high as 5300W / m·K, which is much higher than the thermal conductivity of traditional thermal conductive materials (such as copper and aluminum). Based on this, graphene has a wide range of application prospects in the fields of electronic equipment heat dissipation. For example, placing a thermally conductive gasket made of graphene between a heating device and a radiator can effectively improve the heat conduction efficiency, reduce the operating temperature of the heating device, and thus extend the service life of the heating device.

[0003] However, while existing technologies take advantage of graphene's excellent thermal conductivity, they also face some challenges. Specifically, although graphene has excellent thermal conductivity, its electrical conductivity is also very good, which limits its application in certain insulation scenarios. For example, in electronic devices that require insulation, the presence of graphene may cause circuit short circuits.

[0004] In order to make the graphene gasket have insulating properties, the graphene thermal conductive gasket can be coated with an insulating layer. However, some conventional methods of coating the sheet structure are relatively complicated and it is difficult to achieve a full coating effect, and it is also difficult to ensure the insulation effect. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a method for preparing a coated graphene thermally conductive gasket, which has a simple process and can achieve full coating of the graphene sheet, so that the thermally conductive gasket has both better thermal conductivity and insulation performance.

[0006] In a first aspect, an embodiment of the present application provides a method for preparing a coated graphene thermally conductive pad, which comprises the following steps:

[0007] S1, laminating and stacking a graphene sheet on a first polyimide film, with the graphene sheet being located in the middle of the first polyimide film;

[0008] S2, using a bending process to bend the edge of the first polyimide film exposed from the graphene sheet upward until it is attached to and covers the side and top edge portions of the graphene sheet;

[0009] S3, laminating and covering the middle part of the top surface of the graphene sheet and the first polyimide film above it with a second polyimide film to form a fully covered structure.

[0010] In the above technical solution, polyimide (PI) is a high-performance organic polymer material with excellent mechanical properties, thermal stability, chemical stability and electrical insulation properties. Therefore, polyimide materials are widely used in electronics, electrical, aerospace and other fields. If it is combined with a graphene thermal conductive gasket, the application scenario of the graphene gasket will be further enhanced. Through the above steps, the effective insulation of the graphene thermal conductive gasket can be achieved, and its application performance in the insulation scenario can be improved. At the same time, due to the use of a simple bending process, the thickness of the graphene thermal conductive gasket is reduced, which improves its application potential in space-limited application scenarios, and also simplifies the manufacturing process, reduces costs, and is conducive to its large-scale production.

[0011] A very thin single-sided polyimide (PI) film is used to wrap the graphene gasket: this PI film has good insulation properties and can effectively prevent electrical signal interference and noise caused by the conductivity of graphene, thereby improving the application performance of the graphene thermal conductive gasket in insulation scenarios.

[0012] Wrapping graphene gasket with bending process: By first covering the entire bottom surface of the graphene gasket with PI film, then wrapping the side and part of the upper surface with a bending process, and finally covering the upper surface with a layer of PI film, the graphene gasket can be wrapped with PI film as a whole, which improves its application potential in application scenarios with limited space. Wrap the bottom surface, side surface and part of the surface first, and then cover the top with PI film, so that the graphene gasket can be fully covered, which can achieve insulation on the one hand and reduce the thickness of the film on the other hand.

[0013] Simplify the manufacturing process and reduce costs: This technical solution simplifies the manufacturing process, reduces its cost, and increases its potential for large-scale application by wrapping the graphene gasket with a simple bending process. At the same time, this manufacturing process also makes the production process of the graphene thermal conductive gasket more efficient, which is conducive to its large-scale production.

[0014] In a possible implementation, a first adhesive layer is provided on the surface of the first polyimide film covering the graphene sheet, and the first adhesive layer is bonded to the corresponding surface of the graphene sheet; and a second adhesive layer is provided on the surface of the second polyimide film covering the graphene sheet, and the second adhesive layer is bonded to the corresponding surface of the graphene sheet.

[0015] In the above technical solution, the single-sided PI film refers to a single-sided adhesive PI film. The reason for choosing the PI film is that it has good insulation and high temperature resistance and can form a good bond with the graphene gasket.

[0016] In a possible implementation, after step S3, the method further includes rolling the fully covered structure.

[0017] In a possible implementation, the thickness of the graphene sheet is 0.1-5 mm, and can be optionally 0.3-2 mm.

[0018] In a possible implementation manner, the thickness of the first polyimide film is 3-40 μm, and may be 3-10 μm; the thickness of the second polyimide film is 3-40 μm, and may be 3-10 μm.

[0019] In the above technical solution, the graphene thermal pad can be wrapped by the PI film as a whole, which makes it more adaptable in different application scenarios. PI films of different thicknesses can be selected to wrap the graphene thermal pad according to actual needs to meet different application requirements. The thicker the PI film, the better the insulation and the higher the strength. A relatively thin PI film is selected to reduce thermal performance loss.

[0020] In a possible implementation, before step S1, the first polyimide film is cut so that the area of ​​the first polyimide film is larger than the bottom area of ​​the graphene sheet, and the bent first polyimide film can cover the top edge of the graphene sheet.

[0021] In a possible implementation, the width of the first polyimide film covering the edge portion of the top surface of the graphene sheet is 0.1-0.5 mm, and can be optionally 0.2-0.3 mm.

[0022] In a possible implementation, before step S1, the first polyimide film is cut to have a notch or a cutting line at the edge, so that the number of overlapping layers of the bent first polyimide film covering the top surface of the graphene sheet is ≤2 layers.

[0023] In a possible implementation, before step S3, the second polyimide film is cut so that the area of ​​the second polyimide film is larger than the area in the middle of the top surface of the graphene sheet that is not covered by the first polyimide film.

[0024] In a possible implementation, the width of the first polyimide film where the second polyimide film covers the top surface of the graphene sheet is 0.01-0.5 mm, and may be 0.01-0.3 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of the structure after completing step S1 in the method for preparing a coated graphene thermally conductive gasket provided in an embodiment of the present application;

[0027] Figure 2 A schematic diagram of the structure after completing step S2 in the method for preparing the coated graphene thermally conductive gasket provided in an embodiment of the present application;

[0028] Figure 3 A schematic diagram of the structure after completing step S3 in the method for preparing the coated graphene thermally conductive gasket provided in an embodiment of the present application;

[0029] Figure 4 A schematic diagram of the exploded structure of the coated graphene thermally conductive gasket provided in an embodiment of the present application.

[0030] Icons: 110 - first polyimide film; 120 - graphene sheet; 130 - second polyimide film. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0032] The following is a detailed description of the method for preparing the coated graphene thermally conductive gasket according to the embodiment of the present application.

[0033] Please see Figure 1 to Figure 4 The present invention provides a method for preparing a coated graphene thermally conductive pad, which comprises the following steps:

[0034] S1, laminating and stacking the graphene sheet 120 on the first polyimide film 110, and the graphene sheet 120 is located in the middle of the first polyimide film 110. For the specific structure, see Figure 1 .

[0035] In a possible implementation, the thickness of the graphene sheet 120 is 0.1-5 mm, and may be 0.3-2 mm. The thickness of the first polyimide film 110 is 3-40 μm, and may be 3-10 μm.

[0036] S2, using a bending process to bend the edge of the first polyimide film 110 exposed from the graphene sheet 120 upward until it fits and covers the side and top edge portions of the graphene sheet 120. For a specific structure, see Figure 2 .

[0037] In a possible implementation, before step S1, the first polyimide film 110 is cut so that the area of ​​the first polyimide film 110 is larger than the bottom area of ​​the graphene sheet 120, and the bent first polyimide film 110 can cover the top edge of the graphene sheet 120. Specifically, the width of the first polyimide film 110 covering the top edge of the graphene sheet 120 is 0.1-0.5 mm, and can be 0.2-0.3 mm.

[0038] In a possible implementation, before step S1 , the first polyimide film 110 is cut to have a notch or a cutting line at the edge, so that the number of overlapping layers of the bent first polyimide film 110 covering the top surface of the graphene sheet 120 is ≤ 2 layers.

[0039] In a possible implementation, a first adhesive layer is provided on the surface of the first polyimide film 110 covering the graphene sheet 120 , and the first adhesive layer is bonded to the corresponding surface of the graphene sheet 120 .

[0040] S3, the second polyimide film 130 is laminated and covered on the middle of the top surface of the graphene sheet 120 and the first polyimide film 110 above it to form a fully covered structure. For the specific structure, see Figure 3 .

[0041] In a possible implementation, the thickness of the second polyimide film 130 is 3-40 μm, and may be 3-10 μm.

[0042] In a possible implementation, before step S3, the second polyimide film 130 is cut so that the area of ​​the second polyimide film 130 is larger than the area in the middle of the top surface of the graphene sheet 120 that is not covered by the first polyimide film 110. Specifically, the width of the first polyimide film 110 on the top surface of the graphene sheet 120 covered by the second polyimide film 130 is 0.01-0.5 mm, and can be 0.01-0.3 mm.

[0043] In a possible implementation, a second adhesive layer is provided on the surface of the second polyimide film 130 covering the graphene sheet 120 , and the second adhesive layer is bonded to the corresponding surface of the graphene sheet 120 .

[0044] In a possible implementation, after step S3, a step of rolling the fully covered structure is also included.

[0045] In addition, the present application embodiment provides a coated graphene thermally conductive pad, which is prepared by the above-mentioned preparation method, please refer to Figure 4 The coated graphene thermal conductive pad includes a graphene sheet 120 and a polyimide coating layer coated on all surfaces of the graphene sheet 120, the polyimide coating layer includes a first polyimide film 110 covering the bottom surface, side edges and top edge portions of the graphene sheet 120, and a second polyimide film 130 covering the middle portion of the top surface of the graphene sheet 120 and the first polyimide film 110 above it.

[0046] In a possible implementation, a first adhesive layer is disposed on a surface of the first polyimide film 110 adjacent to the graphene sheet 120, and a second adhesive layer is disposed on a surface of the second polyimide film 130 adjacent to the graphene sheet 120. The thermal conductivity of the first polyimide film 110 is greater than 0.4 W / (m·K), and the thermal conductivity of the second polyimide film 130 is greater than 0.4 W / (m·K).

[0047] In a possible implementation, the thickness of the polyimide coating layer covering the bottom and side surfaces of the graphene sheet 120 is 3-10 μm, and the thickness of the polyimide coating layer covering the top surface of the graphene sheet 120 is 3-30 μm.

[0048] In one possible implementation, the graphene sheet 120 includes multiple layers of graphene films stacked in sequence, an adhesive is provided between two adjacent layers of graphene films, a through hole is provided through the graphene film along the stacking direction, and carbon fiber filaments are fixed in the through hole. Exemplarily, the graphene sheet 120 is a graphene sheet 120 using the technology disclosed in patent number CN202122213698.3.

[0049] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0050] Example 1

[0051] The present invention provides a method for preparing a coated graphene thermally conductive pad, which comprises the following steps:

[0052] S1. Lay the graphene sheet 120 on the first polyimide film 110, and the graphene sheet 120 is located in the middle of the first polyimide film 110, ensuring that the first polyimide film 110 is in full contact with the graphene sheet 120. The graphene sheet 120 is a graphene sheet 120 in the technology disclosed in patent number CN202122213698.3, and the thickness of the graphene sheet 120 is 0.3 mm. The first polyimide film 110 uses a commercially available single-sided adhesive polyimide film with a thickness of 5 μm. It is cut as needed using a cutting machine. For the specific structure, see Figure 1 .

[0053] S2, using a bending process to bend the edge of the first polyimide film 110 that is exposed from the graphene sheet 120 upward until it is attached to and covers the side and top edge portions of the graphene sheet 120. First, one side edge of the first polyimide film 110 is folded upward so that the first polyimide film 110 wraps the side of the graphene sheet 120, and then the other side edge is folded upward in the same manner so that the first polyimide film 110 further wraps the side and part of the top surface of the graphene sheet 120. For the specific structure, see Figure 2 .

[0054] In this embodiment, before step S1, the first polyimide film 110 is cut so that the area of ​​the first polyimide film 110 is larger than the bottom area of ​​the graphene sheet 120, and the first polyimide film 110 after bending can cover the top edge of the graphene sheet 120, and the width of the first polyimide film 110 covering the top edge of the graphene sheet 120 is 0.2 mm. Before step S1, the first polyimide film 110 is cut until there is a notch at the edge, so that the number of overlapping layers of the part of the bent first polyimide film 110 covering the top surface of the graphene sheet 120 is equal to 2 layers. Specifically, the thickness of the part of the polyimide coating layer covering the bottom and side surfaces of the graphene sheet 120 is 5 μm, and the thickness of the part of the polyimide coating layer covering the top surface of the graphene sheet 120 is 5 μm, 10 μm, and 15 μm, respectively.

[0055] S3, the second polyimide film 130 is laminated and covered on the middle of the top surface of the graphene sheet 120 and the first polyimide film 110 above it, ensuring that the second polyimide film 130 is in full contact with the graphene sheet 120 to form a fully covered structure. The second polyimide film 130 is a commercially available single-sided adhesive polyimide film with a thickness of 5 μm. A cutting machine is used to cut as needed. For the specific structure, see Figure 3 .

[0056] S4, rolling the fully covered structure.

[0057] Example 2

[0058] This embodiment provides a method for preparing a coated graphene thermally conductive gasket, which differs from Embodiment 1 in that the thickness of the graphene sheet is 1 mm.

[0059] Example 3

[0060] This embodiment provides a method for preparing a coated graphene thermally conductive gasket, which differs from Embodiment 1 in that the thickness of the graphene sheet is 2 mm.

[0061] Example 4

[0062] This embodiment provides a method for preparing a coated graphene thermally conductive gasket, which differs from Embodiment 1 in that: the thickness of the first polyimide film is 50 μm; the thickness of the second polyimide film is 50 μm.

[0063] Example 5

[0064] This embodiment provides a method for preparing a coated graphene thermally conductive gasket, which differs from Embodiment 4 in that the thickness of the graphene sheet is 1 mm.

[0065] Example 6

[0066] This embodiment provides a method for preparing a coated graphene thermally conductive gasket, which differs from Embodiment 4 in that the thickness of the graphene sheet is 2 mm.

[0067] Comparative Example 1

[0068] This comparative example provides a method for preparing a coated graphene thermally conductive pad, which comprises the following steps:

[0069] S1. The graphene sheet is laminated and stacked on the polyimide film, and the graphene sheet is located in the middle of the polyimide film, ensuring that the polyimide film is in full contact with the graphene sheet. The graphene sheet is a graphene sheet in the technology disclosed in patent number CN202122213698.3, and the thickness of the graphene sheet is 0.3 mm. The polyimide film adopts a commercially available single-sided adhesive polyimide film with a thickness of 5 μm, and is cut as needed using a cutting machine.

[0070] S2. The edge of the polyimide film exposed from the graphene sheet is bent upward by a bending process until it fits and covers the side and top surface of the graphene sheet to form a fully covered structure.

[0071] In this embodiment, before step S1, the polyimide film is cut so that the area of ​​the polyimide film is larger than the bottom area of ​​the graphene sheet, and the bent polyimide film can completely cover the top surface of the graphene sheet, and the width of the overlapping area of ​​the polyimide film relative to the edge on the top surface is 0.2 mm.

[0072] S3, rolling the fully covered structure.

[0073] The various performance parameters of the coated graphene thermally conductive pads of Examples 1-5 and Comparative Example 1 were tested below, and the results are shown in the following table.

[0074]

[0075] It can be seen from the results in the above table that the thickness of the polyimide film used for coating will affect the tensile strength and the coated graphene thermal conductive gasket. When the thickness of the polyimide film (the first polyimide film, the second polyimide film) is selected to be 5μm, the coated graphene thermal conductive gasket has a lower thermal resistance, thereby having better thermal conductivity, while taking into account better insulation performance (breakdown voltage resistance) and strength (tensile strength); and using two polyimide films for coating can obtain better insulation performance and strength than using only one polyimide film.

[0076] In summary, the method for preparing the coated graphene thermally conductive gasket of the embodiment of the present application has a simple process and can achieve full coverage of the graphene sheet, so that the thermally conductive gasket has both better thermal conductivity and insulation performance.

[0077] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a coated graphene thermally conductive pad, characterized in that: It includes the following steps: S1, laminating and stacking a graphene sheet on a first polyimide film, with the graphene sheet being located in the middle of the first polyimide film; S2, using a bending process to bend the edge of the first polyimide film exposed from the graphene sheet upward until it is attached to and covers the side and top edge portions of the graphene sheet; S3, laminating and covering the middle part of the top surface of the graphene sheet and the first polyimide film above it with a second polyimide film to form a fully covered structure.

2. The method for preparing the coated graphene thermally conductive pad according to claim 1, characterized in that: The surface of the graphene sheet covered by the first polyimide film is provided with a first adhesive layer, and the first adhesive layer is used to adhere to the corresponding surface of the graphene sheet; the surface of the graphene sheet covered by the second polyimide film is provided with a second adhesive layer, and the second adhesive layer is used to adhere to the corresponding surface of the graphene sheet.

3. The method for preparing the coated graphene thermally conductive pad according to claim 1 or 2, characterized in that: After step S3, the method further includes the step of rolling the fully covered structure.

4. The method for preparing the coated graphene thermally conductive pad according to claim 1, characterized in that: The thickness of the graphene sheet is 0.1-5 mm, and can be optionally 0.3-2 mm.

5. The method for preparing the coated graphene thermally conductive pad according to claim 1 or 4, characterized in that: The thickness of the first polyimide film is 3-40 μm, and may be 3-10 μm; the thickness of the second polyimide film is 3-40 μm, and may be 3-10 μm.

6. The method for preparing the coated graphene thermally conductive pad according to claim 1, characterized in that: Before step S1, the first polyimide film is cut so that the area of ​​the first polyimide film is larger than the bottom area of ​​the graphene sheet, and the first polyimide film after bending can cover the top edge of the graphene sheet.

7. The method for preparing the coated graphene thermally conductive pad according to claim 1 or 6, characterized in that: The width of the first polyimide film covering the edge portion of the top surface of the graphene sheet is 0.1-0.5 mm, and can be optionally 0.2-0.3 mm.

8. The method for preparing the coated graphene thermally conductive pad according to claim 1, characterized in that: Before step S1, the first polyimide film is cut until the edge has a notch or a cutting line, so that the number of overlapping layers of the bent first polyimide film covering the top surface of the graphene sheet is ≤2 layers.

9. The method for preparing the coated graphene thermally conductive pad according to claim 1, characterized in that: Before step S3, the second polyimide film is cut so that the area of ​​the second polyimide film is larger than the area in the middle of the top surface of the graphene sheet that is not covered by the first polyimide film.

10. The method for preparing the coated graphene thermally conductive pad according to claim 1 or 9, characterized in that: The width of the first polyimide film where the second polyimide film covers the top surface of the graphene sheet is 0.01-0.5 mm, and can be optionally 0.01-0.3 mm.

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