Preparation method of graphene composite heat-conducting gasket

Abstract

The embodiment of the invention provides a preparation method of a graphene composite heat-conducting gasket, and relates to the technical field of graphene. The preparation method of the graphene composite heat-conducting gasket comprises the following steps that a graphene film for pressing is pressed into a corrugated structure, and the corrugated structure is provided with a plurality of soaking channels arranged in the plane direction of the corrugated structure; laminating a layer of graphene film for covering on each of the upper surface and the lower surface of the corrugated structure through an adhesive to form a composite structure; and heating the composite structure for the first time until the adhesive is cured, and then heating for the first time until the adhesive is carbonized or graphitized. According to the preparation method of the graphene composite heat-conducting gasket, the manufacturing cost is low, and the prepared composite structure has excellent heat conduction performance in the longitudinal direction and the plane direction.

Description

Technical Field

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

[0002] Graphene has attracted much attention due to its excellent thermal conductivity. Graphene is a carbon atom 2 The thermal conductivity of the single-layer two-dimensional honeycomb lattice structure material formed by the hybrid orbital can be as high as 5300W / m·K, which is much higher than that of traditional thermal conductive materials (such as copper, aluminum, etc.). Therefore, graphene has a wide range of application prospects in meeting the heat dissipation needs of electronic devices such as high-power LEDs and CPUs.

[0003] The current preparation process mainly uses a directional process to sort graphene, and then compound it with resin to prepare a composite material. The composite material has high thermal conductivity in the longitudinal direction of the graphene lattice structure, but poor thermal uniformity in the plane direction, which will cause uneven distribution of heat on the composite material during use, affecting its thermal conductivity. In addition, the manufacturing process of existing graphene composite materials is complicated and costly, which also limits its large-scale application.

[0004] Therefore, how to improve the thermal conductivity of graphene composites in the longitudinal and planar directions while reducing their manufacturing costs is an urgent problem to be solved in this field. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a method for preparing a graphene composite thermally conductive gasket, which has a low manufacturing cost and the prepared composite structure has excellent thermal conductivity in both the longitudinal and planar directions.

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

[0007] Pressing the graphene film for pressing into a corrugated structure, wherein the corrugated structure has a plurality of heat-dissipating channels arranged along the plane direction thereof;

[0008] A layer of covering graphene film is laminated on the upper surface and the lower surface of the corrugated structure respectively by adhesive to form a composite structure;

[0009] The composite structure is heated for a first time until the binder is cured, and then heated for a second time until the binder is carbonized or graphitized.

[0010] In the above implementation process, the pressing graphene film is pressed to form a corrugated structure, which can increase the thickness of the graphene film, thereby improving the thermal conductivity of the graphene composite thermally conductive gasket in the longitudinal direction (i.e., thickness direction); by laminating a layer of covering graphene film on the upper surface and the lower surface of the corrugated structure respectively through an adhesive, the heat distribution channel can be evenly distributed in the plane direction, thereby improving the heat distribution performance of the graphene composite thermally conductive gasket in the plane direction, and improving the overall strength of the graphene composite thermally conductive gasket; by heating twice, first curing the adhesive to exert a stable bonding effect, and then carbonizing or graphitizing the adhesive, the thermal resistance between the graphene film interfaces can be reduced, thereby improving its thermal conductivity. The above process only requires the use of graphene film and adhesive, which can simplify the manufacturing process of the graphene thermally conductive gasket and reduce its manufacturing cost.

[0011] In a possible implementation, the thickness of the graphene film for pressing is 100 to 500 μm;

[0012] The thickness of the corrugated structure is 0.1 to 3 mm, and can be optionally 0.3 to 2 mm;

[0013] The thickness of the covering graphene film is 100 to 300 μm.

[0014] In a possible implementation, the pressing method is as follows: the pressing graphene film has a plurality of pressing lines arranged along its plane direction and spaced apart, and each of the pressing lines along the pressing graphene film is pressed in turn in an upward and downward direction to bend it.

[0015] In the above implementation process, by embossing the graphene film to form a wavy corrugated structure, not only can the thickness of the graphene film be increased, thereby improving its thermal conductivity in the longitudinal direction, but also a heat-distributing channel is constructed to improve its heat-distributing performance in the planar direction, thereby solving the problem of poor thermal conductivity of graphene in the planar direction in the prior art and expanding its application range in fields with high thermal conductivity requirements.

[0016] In a possible implementation, the pressure during pressing is 5-15 MPa and the temperature is 150-250°C.

[0017] In one possible implementation, the method for forming a composite structure is: the pressed lines are arranged in two layers, first applying adhesive on the upper and lower surfaces of the corrugated structure, and then laminating the pressed lines of the upper layer with the pressed graphene film stacked on the upper surface, and laminating the pressed lines of the lower layer with the first graphene film stacked on the lower surface.

[0018] In the above implementation process, the method of forming the composite structure is simple, which can not only improve its thermal conductivity, but also improve its overall structural strength and extend its service life.

[0019] In a possible implementation, the adhesive is applied to both sides of the pressing line;

[0020] And / or, a groove is made on the lower surface of the covering graphene film stacked on the upper surface so that the compression line of the upper layer is embedded in the groove of the covering graphene film, and a groove is made on the upper surface of the covering graphene film stacked on the lower surface so that the compression line of the lower layer is embedded in the groove of the covering graphene film.

[0021] In the above implementation process, by applying adhesive on both sides of the pressing line, not only the fixed connection between adjacent graphene films is achieved, but also the barrier between the graphene films caused by the adhesive is reduced, thereby improving the longitudinal heat conduction performance. By grooving and embedding, the structural stability between the graphene films can be improved, the end area can be increased, and the heat conduction effect can be improved.

[0022] In a possible implementation, the composite structure is firstly subjected to a rolling process until each layer is tightly combined and maintains a corrugated structure, and then subjected to a heat treatment, wherein the rolling pressure is 3 to 8 MPa.

[0023] In the above implementation process, the composite structure is rolled, which can not only tightly combine the covering graphene film with the corrugated structure, improve the overall strength of the graphene composite thermal conductive gasket, and make it more durable in practical applications, but also will not damage the corrugated structure, so that the heat equalization channel therein can play a good heat equalization role.

[0024] In a possible implementation, the temperature during the first heating is 100-200° C., and the time is 1-3 hours.

[0025] In the above implementation process, the composite structure is heated for the first time to remove excess moisture and ensure that the adhesive is cured.

[0026] In a possible implementation, the second heating is performed at a temperature of 800 to 1500° C. for a time of 1 to 3 hours.

[0027] In the above implementation process, by heating the composite structure for a second time, the cured adhesive can be carbonized or graphitized, which can reduce the thermal resistance between the graphene film interfaces and thus improve the thermal conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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.

[0029] Figure 1 A schematic diagram of a process for preparing a graphene composite thermally conductive pad provided in an embodiment of the present application;

[0030] Figure 2 This is a schematic diagram of the structure of a graphene composite thermally conductive gasket prepared in an embodiment of the present application;

[0031] Figure 3 for Figure 2 Schematic diagram of the decomposition structure.

[0032] Icon: 110 - first graphene film for covering; 120 - graphene film for pressing; 130 - second graphene film for covering. DETAILED DESCRIPTION

[0033] 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.

[0034] The following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0036] In the description of this application, it should be noted that the terms "upper", "lower", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0037] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] Please see Figures 1 to 3 The present embodiment provides a method for preparing a graphene composite thermally conductive gasket, which comprises the following steps:

[0039] S1. Pressing the graphene film 120 for pressing into a corrugated structure, wherein the corrugated structure has a plurality of heat-dissipating channels arranged along its plane direction.

[0040] In the present application, the graphene film (graphene film 120 for pressing, graphene film for covering) is a film material structure purchased from the market, which has a lattice structure along the plane direction, has a good planar heat distribution function, and has good flexibility and can be bent at will.

[0041] In a possible implementation, the thickness of the pressing graphene film 120 is 100-500 μm;

[0042] The thickness of the corrugated structure is 0.1-3 mm, and can be selected as 0.3-2 mm;

[0043] In a possible implementation, the pressing method is as follows: the pressing graphene film 120 has a plurality of pressing lines arranged along its plane and spaced apart, and the pressing lines of the pressing graphene film are pressed in the upward and downward directions to bend the film. The pressing pressure is 5 to 15 MPa and the temperature is 150 to 250°C.

[0044] As an embodiment, the specific process of step S1 includes: placing the graphene film on the mold of the corrugator, and pressing the graphene film into a wavy corrugated structure by adjusting the pressure and temperature of the corrugator, wherein the grooves in the corrugated structure are arranged side by side along the plane direction to serve as a uniform channel.

[0045] S2. A layer of covering graphene film is laminated on the upper surface and the lower surface of the corrugated structure respectively by adhesive to form a composite structure.

[0046] In a possible implementation, the thickness of the covering graphene film is 100-300 μm.

[0047] In one possible implementation, the method for forming a composite structure is: the pressed lines are arranged in two layers, first applying adhesive on the upper and lower surfaces of the corrugated structure, and then bonding the upper layer's pressed lines to the pressed graphene film 120 stacked on the upper surface, and bonding the lower layer's pressed lines to the pressed graphene film 120 stacked on the lower surface.

[0048] Among them, the upper surface of the corrugated structure is mainly a plane composed of the pressing lines of the upper layer, and the lower surface of the corrugated structure is mainly a plane composed of the pressing lines of the lower layer.

[0049] In one possible implementation, the adhesive is applied only on both sides of the pressed line;

[0050] And / or, a groove is made on the lower surface of the covering graphene film stacked on the upper surface so that the compression line of the upper layer is embedded in the groove of the covering graphene film, and a groove is made on the upper surface of the covering graphene film stacked on the lower surface so that the compression line of the lower layer is embedded in the groove of the covering graphene film.

[0051] As an implementation mode, the specific process of step S2 includes: evenly applying the adhesive on the upper and lower surfaces of the corrugated structure, and then laminating the first covering graphene film 110 on the lower surface of the corrugated structure, and laminating the second covering graphene film 130 on the upper surface of the corrugated structure. The heat-averaging channel in the corrugated structure is covered with the covering graphene film to form a heat-averaging channel closed on all sides, which can improve the heat-averaging effect.

[0052] S3. Roll the composite structure until each layer is tightly combined and the corrugated structure is maintained.

[0053] In a possible implementation, the roller pressing pressure is 3-8 MPa.

[0054] As an implementation mode, the specific process of step S3 includes: passing the composite structure through a pressure roller, and adjusting the pressure and gap of the pressure roller so that the corrugated structure and the upper and lower covering graphene films are tightly combined to form a stable composite structure.

[0055] S4, heating the composite structure for the first time until the adhesive is cured.

[0056] In a possible implementation, the temperature during the first heating is 100-200° C., and the time is 1-3 hours.

[0057] As an implementation mode, the specific process of step S4 includes: sending the rolled composite structure into an oven to remove excess moisture and ensure that the adhesive is cured.

[0058] S5. Heat again until the binder is carbonized or graphitized.

[0059] In a possible implementation, the second heating is performed at a temperature of 800 to 1500° C. for a time of 1 to 3 hours.

[0060] As an implementation method, the specific process of step S5 includes: placing the composite structure after the first heating into a high-temperature furnace, and adjusting the temperature and time of the high-temperature furnace to carbonize or graphitize the adhesive, thereby reducing the thermal resistance between the graphene film interfaces, thereby improving the overall thermal conductivity.

[0061] In the embodiment of the present application, a layer of adhesive is evenly applied on the upper surface (pressing line of the upper layer) and the lower surface (pressing line of the lower layer) of the corrugated structure, and a layer of covering graphene film is correspondingly attached to each other, and the three are tightly combined into a composite structure by pressing with a pressure roller. This composite structure can effectively improve the heat distribution performance of the graphene film in the plane direction, and during use, it can ensure the uniform distribution of heat on the gasket and improve its thermal conductivity.

[0062] Moreover, the manufacturing process of the above preparation method is simple, and mainly adopts equipment such as corrugating machines and pressure rollers, which are widely used in industrial production, have low cost, short process flow and high production efficiency, which can effectively reduce the manufacturing cost of graphene thermal conductive gaskets and is conducive to their large-scale application.

[0063] Please see Figure 2 and Figure 3 This embodiment also provides a graphene composite thermally conductive gasket prepared by the above-mentioned preparation method, and its structure is as follows:

[0064] The graphene composite thermally conductive gasket includes a first covering graphene film 110, a corrugated structure and a second covering graphene film 130 which are stacked in sequence along the longitudinal direction. The first covering graphene film 110, the corrugated structure and the second covering graphene film 130 are all made of graphene, and the corrugated structure is provided with a plurality of heat-distributing channels arranged along the planar direction.

[0065] In this embodiment, the thickness of the first covering graphene film 110 and the second covering graphene film 130 are both 200 microns; the thickness of the corrugated structure along the first direction is 1 millimeter, and the cross-sectional shape of the heat-averaging channel is a triangle.

[0066] In this embodiment, the corrugated structure includes a pressing graphene film 120, the thickness of the pressing graphene film 120 is 200 microns, the pressing graphene film 120 has a plurality of pressing lines arranged along the second direction and spaced apart, and the pressing graphene film 120 is bent in opposite directions along each pressing line in turn to form a corrugated structure.

[0067] The pressing lines of the pressing graphene film 120 are arranged in two layers, the upper pressing lines are in contact with the first covering graphene film 110, and the lower pressing lines are in contact with the second covering graphene film 130. The pressing line positions of the corrugated structure are directly in contact with the corresponding first covering graphene film 110 and second covering graphene film 130, and are bonded together by adhesives on both sides of the pressing lines.

[0068] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0069] Example 1

[0070] This embodiment provides a method for preparing a graphene composite thermally conductive pad, which comprises the following steps:

[0071] Step 1: Place a 100 μm thick graphene film for pressing on the mold of a corrugator, and press the graphene film into a wavy corrugated structure by adjusting the pressure of the corrugator to 10 MPa and the temperature to 200°C. The thickness of the corrugated structure is 0.3 mm.

[0072] Step 2: Evenly apply a layer of adhesive on the upper and lower surfaces of the corrugated structure, and stick a first covering graphene film with a thickness of 100 μm on the lower surface, and stick a second covering graphene film with a thickness of 100 μm on the upper surface to form a composite structure.

[0073] Step three: pass the composite structure through a pressure roller, and adjust the pressure of the pressure roller to 5 MPa so that the corrugated structure, the first covering graphene film, and the second covering graphene film are tightly combined.

[0074] Step 4: Send the composite structure into the oven and adjust the oven temperature to 150°C for 2 hours to remove excess moisture and ensure the adhesive is cured.

[0075] Step 5: Place the cured composite structure into a high temperature furnace, and adjust the temperature of the high temperature furnace to 1000° C. for 2 hours to allow the adhesive to undergo carbonization or graphitization reaction to form a stable composite structure.

[0076] Through the above steps, a composite corrugated structure based on graphene film can be obtained. The structure has good longitudinal thermal conductivity and planar heat distribution performance, and also has high overall strength and carbonization or graphene efficiency, and is suitable for heat dissipation applications of various electronic devices.

[0077] Example 2

[0078] This embodiment provides a method for preparing a graphene composite thermally conductive gasket, which differs from Embodiment 1 in that: the thickness of the pressing graphene film is 200 μm, and the thickness of the corrugated structure is 0.2 mm; the thickness of the first covering graphene film is 200 μm; and the thickness of the second covering graphene film is 100 μm.

[0079] Example 3

[0080] This embodiment provides a method for preparing a graphene composite thermally conductive gasket, which differs from Embodiment 1 in that the temperature of the high-temperature furnace in step five is 800° C. and the time is 2 hours.

[0081] Comparative Example 1

[0082] This comparative example provides a method for preparing a graphene composite thermally conductive gasket, which differs from Example 1 in that step five is not performed, that is, the adhesive is not carbonized or graphitized.

[0083] The thermal conductivity of the graphene composite thermally conductive pads of Examples 1 to 3 and Comparative Example 1 was tested as follows:

[0084] (1) Longitudinal thermal conductivity: The relative positions of the upper and lower surfaces of the graphene composite thermally conductive gasket were detected to obtain the longitudinal thermal conductivity. The detection method was as follows: the thermal diffusion coefficient was tested using the NETZSCH LFA467 equipment. The gasket size was cut to a diameter of 12.7 mm, and the test mode was selected as the conventional test mode to test the thermal diffusion coefficient. The specific heat capacity of the gasket was then tested using the DSC differential scanning calorimetry method, and the density of the gasket was tested using the water displacement method. Finally, the thermal conductivity coefficient was calculated using the formula thermal diffusion coefficient = thermal diffusion coefficient * specific heat capacity * density.

[0085] (2) Thermal conductivity in the plane direction: The opposite side of the graphene composite thermally conductive gasket is tested to obtain the horizontal thermal conductivity. The test method is: the thermal diffusion coefficient is tested using the NETZSCH LFA467 equipment, the gasket size is cut to a diameter of 25.4 mm, the test mode is selected as In-plane, and the thermal diffusion coefficient is tested. Then the specific heat capacity of the gasket is tested using the DSC differential scanning calorimetry method, and the density of the gasket is tested using the water displacement method. Finally, the thermal conductivity coefficient is calculated using the formula thermal diffusion coefficient * specific heat capacity * density.

[0086] The test results are shown in the following table.

[0087] Example 1 Example 2 Example 3 Comparative Example 1 Longitudinal thermal conductivity (W / m K) 1830 1720 1780 1260 Horizontal thermal conductivity (W / m K) 1650 1580 1620 810

[0088] In summary, the method for preparing the graphene composite thermally conductive gasket according to the embodiment of the present application has a low manufacturing cost, and the prepared composite structure has excellent thermal conductivity in both the longitudinal and planar directions.

[0089] 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 graphene composite thermally conductive pad, characterized in that: It includes the following steps: Pressing the graphene film for pressing into a corrugated structure, wherein the corrugated structure has a plurality of heat-dissipating channels arranged along the plane direction thereof; A layer of covering graphene film is laminated on the upper surface and the lower surface of the corrugated structure respectively by adhesive to form a composite structure; The composite structure is heated for a first time until the binder is cured, and then heated for a second time until the binder is carbonized or graphitized.

2. The method for preparing the graphene composite thermally conductive pad according to claim 1, characterized in that: The thickness of the graphene film for pressing is 100 to 500 μm; The thickness of the corrugated structure is 0.1 to 3 mm, and can be optionally 0.3 to 2 mm; The thickness of the covering graphene film is 100 to 300 μm.

3. The method for preparing the graphene composite thermally conductive pad according to claim 1, characterized in that: The pressing method is as follows: the pressing graphene film has a plurality of pressing lines arranged along its plane direction and spaced apart, and each pressing line along the pressing graphene film is pressed in turn in the upward and downward directions to bend it.

4. The method for preparing the graphene composite thermally conductive pad according to claim 2 or 3, characterized in that: The pressure during pressing is 5 to 15 MPa and the temperature is 150 to 250°C.

5. The method for preparing the graphene composite thermally conductive pad according to claim 3, characterized in that: The method for forming a composite structure is as follows: the pressed lines are arranged in two layers, firstly applying adhesive on the upper surface of the corrugated structure, then laminating the pressed lines of the upper layer with the pressed graphene film stacked on the upper surface, and then laminating the pressed lines of the lower layer with the first graphene film stacked on the lower surface.

6. The method for preparing the graphene composite thermally conductive pad according to claim 5, characterized in that: The adhesive is applied to both sides of the pressing line; And / or, a groove is made on the lower surface of the covering graphene film stacked on the upper surface so that the compression line of the upper layer is embedded in the groove of the covering graphene film, and a groove is made on the upper surface of the covering graphene film stacked on the lower surface so that the compression line of the lower layer is embedded in the groove of the covering graphene film.

7. The method for preparing the graphene composite thermally conductive pad according to claim 5, characterized in that: The composite structure is firstly subjected to roller pressing treatment until each layer is tightly combined and the corrugated structure is maintained, and then subjected to heating treatment, wherein the roller pressing pressure is 3-8 MPa.

8. The method for preparing the graphene composite thermally conductive pad according to claim 1, characterized in that: The temperature during the first heating is 100 to 200° C. and the time is 1 to 3 hours.

9. The method for preparing the graphene composite thermally conductive pad according to claim 1, characterized in that: The temperature of the second heating is 800-1500°C and the time is 1-3 hours.

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