阅读说明：本技术 导热垫片及其制备方法和应用 (Heat-conducting gasket and preparation method and application thereof ) 是由 虞锦洪 李茂华 江南 褚伍波 于 2021-07-16 设计创作，主要内容包括：本发明涉及一种导热垫片及其制备方法和应用。该制备方法包括如下步骤：提供原材料,原材料包括相变材料、导热填料、基体材料以及交联剂,导热填料的轴向长度与径向长度的比值大于1；在第一温度下,将原材料混合,基体材料在交联剂的存在下发生固化交联反应形成基体,得到预制品,其中,第一温度大于相变材料的熔点且小于相变材料的沸点,基体的交联密度为0.5％-5％；以及在第二温度下,将预制品进行冷冻处理,得到导热垫片,第二温度小于相变材料的熔点且温度差达到30℃以上,导热垫片中导热填料的轴向与导热垫片的表面之间的夹角为60度-90度。该制备方法制得的导热垫片具有优异的导热性能以及高温保形性。(The invention relates to a heat-conducting gasket and a preparation method and application thereof. The preparation method comprises the following steps: providing raw materials, wherein the raw materials comprise a phase-change material, a heat-conducting filler, a base material and a cross-linking agent, and the ratio of the axial length to the radial length of the heat-conducting filler is greater than 1; mixing the raw materials at a first temperature, and carrying out curing and crosslinking reaction on a matrix material in the presence of a crosslinking agent to form a matrix to obtain a prefabricated product, wherein the first temperature is higher than the melting point of the phase-change material and lower than the boiling point of the phase-change material, and the crosslinking density of the matrix is 0.5-5%; and freezing the prefabricated product at a second temperature to obtain the heat-conducting gasket, wherein the second temperature is lower than the melting point of the phase-change material, the temperature difference reaches more than 30 ℃, and the included angle between the axial direction of the heat-conducting filler in the heat-conducting gasket and the surface of the heat-conducting gasket is 60-90 degrees. The heat-conducting gasket prepared by the preparation method has excellent heat-conducting property and high-temperature shape-preserving property.)

1. The preparation method of the heat conduction gasket is characterized by comprising the following steps of:

providing a raw material, wherein the raw material comprises a phase-change material, a heat-conducting filler, a matrix material and a cross-linking agent, and the ratio of the axial length to the radial length of the heat-conducting filler is greater than 1;

mixing the raw materials at a first temperature, wherein the matrix material is subjected to a curing and crosslinking reaction in the presence of the crosslinking agent to form a matrix, so as to obtain a preform, wherein the first temperature is higher than the melting point of the phase-change material and lower than the boiling point of the phase-change material, and the crosslinking density of the matrix is 0.5-5%; and

and freezing the preform at a second temperature to obtain the heat-conducting gasket, wherein the second temperature is lower than the melting point of the phase-change material, the temperature difference is higher than 30 ℃, and an included angle between the axial direction of the heat-conducting filler in the heat-conducting gasket and the surface of the heat-conducting gasket is 60-90 degrees.

2. The method for producing a thermal gasket according to claim 1, wherein the thickness of the preform is 0.3mm to 3 mm.

3. The method for manufacturing a thermal gasket according to claim 1, wherein the thermal conductive filler is selected from a rod-shaped thermal conductive filler, an ellipsoid-shaped thermal conductive filler, or a sheet-shaped thermal conductive filler.

4. The method of manufacturing a thermal gasket according to claim 3, wherein the particle size of the thermal conductive filler is 0.5 μm to 500 μm.

5. The method for preparing the heat conduction gasket according to the claim 1, wherein the mass fraction of the phase change material in the raw material is 45% -89%;

and/or the mass fraction of the heat-conducting filler in the raw material is 5-49%;

and/or the mass fraction of the base material in the raw material is 5-20%;

and/or the mass fraction of the cross-linking agent in the raw material is 0.01-16%.

6. The method for preparing a heat conductive gasket according to claim 1, wherein the temperature difference between the first temperature and the melting point of the phase change material is 10 ℃ to 20 ℃.

7. The method for manufacturing a thermal pad according to any one of claims 1 to 6, wherein the phase change material comprises at least one of polyethylene glycol, polyvinyl alcohol, polypropylene alcohol, octadecyl, or paraffin;

and/or the heat conducting filler comprises at least one of carbon fiber, carbon nano tube, graphite, graphene, diamond, aluminum oxide, magnesium oxide, silicon oxide, boron nitride, aluminum nitride, copper or silver;

and/or the matrix material comprises at least one of silicone oil, silicone gel, acrylic acid, acrylic rubber, acrylate copolymer resin, ethylene-vinyl acetate copolymer resin, polyurethane rubber or polyvinyl ether resin;

and/or the cross-linking agent comprises at least one of N, N' -methylene bisacrylamide, silicone hydride, dicumyl peroxide, benzoyl peroxide or di-tert-butyl peroxide.

8. The method for manufacturing a thermal pad according to any one of claims 1 to 6, wherein the raw material further comprises an auxiliary agent, and the auxiliary agent comprises at least one of an initiator, a platinum catalyst, a surface modifier, a rheology modifier, or an antioxidant.

9. A thermal gasket obtained by the method according to any one of claims 1 to 8.

10. Use of the thermal gasket of claim 9 in an electronic product.

Technical Field

The invention relates to the field of electronic products, in particular to a heat conduction gasket, and a preparation method and application thereof.

Background

With the integration of microelectronic devices becoming higher and higher, the heat dissipation problem becomes more and more a key problem restricting the development of the industry, and the heat conduction gasket is widely applied to the field of electronics and electricians as a key material for improving the heat conduction coefficient between a heat source and a cold source.

In order to increase the thermal conductivity of the thermal pad, a method of adding a thermal conductive filler and a phase change material is generally adopted. However, with the increase of the usage amount of the heat conductive filler and the phase change material, when the heat conductive gasket is applied, when the temperature is higher than the melting point of the phase change material, the shape is difficult to keep complete, and the phase change material is easy to overflow, so the addition ratio of the heat conductive filler and the phase change material is limited, the heat conductivity coefficient cannot be further improved, and the increasing heat dissipation requirements cannot be met.

Disclosure of Invention

In view of the above, there is a need to provide a heat conductive gasket, a method for manufacturing the same, and an application of the same, wherein the heat conductive gasket manufactured by the manufacturing method has excellent heat conductive performance and high temperature conformality, and can be better applied to electronic products as a heat conductive device.

The preparation method of the heat conduction gasket provided by the invention comprises the following steps:

providing a raw material, wherein the raw material comprises a phase-change material, a heat-conducting filler, a matrix material and a cross-linking agent, and the ratio of the axial length to the radial length of the heat-conducting filler is greater than 1;

mixing the raw materials at a first temperature, wherein the matrix material is subjected to a curing and crosslinking reaction in the presence of the crosslinking agent to form a matrix, so as to obtain a preform, wherein the first temperature is higher than the melting point of the phase-change material and lower than the boiling point of the phase-change material, and the crosslinking density of the matrix is 0.5-5%; and

and freezing the preform at a second temperature to obtain the heat-conducting gasket, wherein the second temperature is lower than the melting point of the phase-change material, the temperature difference reaches more than 30 ℃, and an included angle between the axial direction of the heat-conducting filler in the heat-conducting gasket and the surface of the heat-conducting gasket is 60-90 degrees.

In one embodiment, the thickness of the preform is between 0.3mm and 3 mm.

In one embodiment, the thermally conductive filler is selected from a rod-shaped thermally conductive filler, an ellipsoid-shaped thermally conductive filler, or a plate-shaped thermally conductive filler.

In one embodiment, the thermally conductive filler has a particle size of 0.5 μm to 500 μm.

In one embodiment, the mass fraction of the phase change material in the raw material is 45% to 89%;

and/or the mass fraction of the heat-conducting filler in the raw material is 5-49%;

and/or the mass fraction of the base material in the raw material is 5-20%;

and/or the mass fraction of the cross-linking agent in the raw material is 0.01-16%.

In one embodiment, the temperature difference between the first temperature and the melting point of the phase change material is 10 ℃ to 20 ℃.

In one embodiment, the phase change material comprises at least one of polyethylene glycol, polyvinyl alcohol, polypropylene alcohol, octadecyl, or paraffin;

and/or the heat conducting filler comprises at least one of carbon fiber, carbon nano tube, graphite, graphene, diamond, aluminum oxide, magnesium oxide, silicon oxide, boron nitride, aluminum nitride, copper or silver;

and/or the matrix material comprises at least one of silicone oil, silicone gel, acrylic acid, acrylic rubber, acrylate copolymer resin, ethylene-vinyl acetate copolymer resin, polyurethane rubber or polyvinyl ether resin;

and/or the cross-linking agent comprises at least one of N, N' -methylene bisacrylamide, silicone hydride, dicumyl peroxide, benzoyl peroxide or di-tert-butyl peroxide.

In one embodiment, the raw material further comprises an auxiliary agent, the auxiliary agent comprising at least one of an initiator, a platinum catalyst, a surface modifier, a rheology modifier, or an antioxidant.

The heat-conducting gasket is prepared by the preparation method of the heat-conducting gasket.

The application of the heat-conducting gasket in the electronic product is disclosed.

In the preparation method of the heat conduction gasket, the second temperature is lower than the melting point of the phase change material, and the temperature difference is more than 30 ℃, so that the prefabricated product is frozen rapidly, the heat dissipation direction of the prefabricated product is vertical to the surface of the prefabricated product, the solidification direction of the phase change material is vertical to the surface of the prefabricated product, the heat conduction filler can rotate in the freezing treatment process, an included angle of 60-90 degrees is formed between the axial direction of the heat conduction filler and the heat conduction gasket, and a heat conduction passage is formed together with the solidified phase change material, so that the heat conduction gasket has excellent heat conduction performance. Meanwhile, the crosslinking density of the matrix of the heat-conducting gasket is between 0.5% and 5%, the mechanical strength is moderate, on one hand, the rotation of the heat-conducting filler is not influenced, on the other hand, the prepared heat-conducting gasket has excellent high-temperature shape-preserving performance, can be better used as a heat-conducting device to be applied to electronic products, can still keep the integrity of the shape even if the temperature is higher than the melting point of the phase-change material, and solves the problem of overflow of the phase-change material.

In addition, the preparation method is simple and is suitable for industrial production; the heat conducting gasket has universality, and heat conducting gaskets with different performances can be obtained by adopting different types of heat conducting fillers.

Drawings

FIG. 1 is a schematic diagram of a preform according to one embodiment of the present invention;

fig. 2 is a schematic structural diagram of a thermal pad according to an embodiment of the present invention.

In the figure, 10, a thermally conductive filler; 20. a phase change material; 30. a substrate.

Detailed Description

The heat conductive gasket provided by the present invention, and the preparation method and application thereof will be further described below.

The preparation method of the heat conduction gasket provided by the invention comprises the following steps:

s1, providing raw materials, wherein the raw materials comprise a phase change material 20, a heat conduction filler 10, a base material and a cross-linking agent, and the ratio of the axial length to the radial length of the heat conduction filler 10 is greater than 1;

s2, mixing the raw materials at a first temperature, and carrying out curing and crosslinking reaction on the matrix material in the presence of a crosslinking agent to form a matrix to obtain a preform, wherein the first temperature is higher than the melting point of the phase-change material and lower than the boiling point of the phase-change material, and the crosslinking density of the matrix is 0.5-5%; and

and S3, freezing the prefabricated product at a second temperature to obtain the heat conduction gasket, wherein the second temperature is lower than the melting point of the phase change material, the temperature difference reaches more than 30 ℃, and the included angle between the axial direction of the heat conduction filler 10 in the heat conduction gasket and the surface of the heat conduction gasket is 60-90 degrees.

It should be noted that the crosslinking density is equal to the percentage of the structural units to be crosslinked to the total structural units, for example, when the base material is acrylic acid and the crosslinking agent is N, N ' -methylenebisacrylamide, the crosslinking density is equal to the percentage of the number of molecules of N, N ' -methylenebisacrylamide to the total number of molecules of N, N ' -methylenebisacrylamide and acrylic acid.

According to the preparation method of the heat conduction gasket, when the crosslinking density of the matrix 30 is less than 0.5%, the mechanical strength of the matrix 30 is too low, and the high-temperature shape retention of the heat conduction gasket is insufficient, so that the heat conduction gasket cannot keep the structural integrity during application, and the phase change material 20 is easy to overflow; when the crosslinking density of the matrix 30 of the heat-conducting gasket is more than 5%, the mechanical strength of the matrix 30 is too high, and the rotation of the heat-conducting filler 10 in the freezing treatment process can be hindered, so that the crosslinking density of the matrix 30 is 0.5% -5%, the mechanical strength is moderate, on one hand, the rotation of the heat-conducting filler 10 is not influenced, and on the other hand, the prepared heat-conducting gasket has excellent high-temperature shape-preserving performance. Specifically, the crosslinking density of the matrix 30 is controlled by the type and amount of the matrix material, the type of the crosslinking agent and the amount of the crosslinking agent.

In one embodiment, in step S1, the matrix material includes a polymer material or a monomer of a polymer material, specifically, the matrix material includes at least one of a thermosetting resin, a thermosetting resin monomer, a rubber or a rubber monomer, and preferably includes at least one of silicone oil, silicone gel, acrylic acid, acrylic rubber, acrylate copolymer resin, ethylene-vinyl acetate copolymer resin, urethane rubber or polyvinyl ether resin.

In one embodiment, the mass fraction of the matrix material in the raw material is 5% to 20%, and the mass fraction of the matrix material in the raw material should be minimized to ensure that the phase change material does not overflow, and therefore, the mass fraction of the matrix material in the raw material is preferably 5% to 10%.

In one embodiment, the crosslinking agent comprises at least one of N, N' -methylenebisacrylamide, silicone oil, dicumyl peroxide, benzoyl peroxide, or di-t-butyl peroxide. The mass fraction of the crosslinking agent in the raw material is 0.01% to 16%, and more preferably 0.1% to 16%.

In order to make the heat conductive filler 10 rotate more smoothly during the freezing process and improve the longitudinal thermal conductivity of the heat conductive gasket, in one embodiment, the heat conductive filler 10 is selected from a rod-shaped heat conductive filler, an ellipsoidal heat conductive filler, or a sheet-shaped heat conductive filler. The particle diameter of the heat conductive filler 10 is 0.5 μm to 500. mu.m, and more preferably 1 μm to 200. mu.m.

It can be understood that, when the heat conductive filler 10 is a rod-shaped heat conductive filler or an ellipsoidal heat conductive filler, the axial direction of the heat conductive filler 10 is the length direction of the heat conductive filler 10, and the radial direction is the diameter direction perpendicular to the axial direction; when the heat conductive filler 10 is selected from the sheet-shaped heat conductive fillers, the axial direction of the heat conductive filler 10 is the extending direction of the heat conductive filler 10, and the radial direction is the thickness direction perpendicular to the axial direction.

In one embodiment, the thermally conductive filler 10 includes at least one of carbon fiber, carbon nanotube, graphite, graphene, diamond, alumina, magnesia, silica, boron nitride, aluminum nitride, copper, or silver. The mass fraction of the heat conductive filler 10 in the raw material is 5% to 49%, and more preferably 30% to 49%.

In one embodiment, the phase change material 20 includes at least one of polyethylene glycol, polyvinyl alcohol, polypropylene alcohol, octadecyl, or paraffin.

In order to improve the heat conductivity of the heat conducting pad as much as possible and avoid the problem of overflowing of the phase change material 20, in an embodiment, the mass fraction of the phase change material 20 in the raw material is 45% to 89%, and more preferably 45% to 70%.

In one embodiment, the raw material further comprises an auxiliary agent, the auxiliary agent comprising at least one of an initiator, a platinum catalyst, a surface modifier, a rheology modifier, or an antioxidant.

The initiator is capable of causing the ambient cure crosslinking reaction, and when the auxiliary agent comprises an initiator, the initiator comprises a peroxide, an azo initiator, such as ammonium persulfate, benzoyl peroxide, azobisisobutyronitrile, and in one embodiment, the mass fraction of the initiator in the raw material is 0.05% to 1%, and more preferably 0.1% to 0.5%.

When the promoter includes a platinum catalyst, in one embodiment, the mass fraction of the platinum catalyst in the raw material is 1% to 5%, and more preferably 1% to 2%.

The surface assistant enables the thermally conductive filler 10 to be better dispersed, and when the assistant includes the surface modifier, the surface modifier includes at least one of a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, or stearic acid; in one embodiment, the mass fraction of the surface modifier in the raw material is 0.05% to 2%, more preferably 0.1% to 1%.

When the adjunct comprises a rheology modifier, the rheology modifier comprises at least one of ethyl acetate, toluene, ethylbenzene, acetone, ethanol, isopropanol, or an alkane solvent; in one embodiment, the rheology modifier is present in the raw material in a mass fraction of 0.5% to 10%, more preferably 1% to 5%.

When the auxiliary agent comprises an antioxidant, the antioxidant comprises at least one of a hindered phenol antioxidant, a hindered amine antioxidant, a thioester or a phosphite ester; in one embodiment, the antioxidant is present in the raw material in an amount of 0.01% to 0.1% by mass, more preferably 0.05% to 0.1% by mass.

In step S2, in order to avoid the volatilization of the matrix material at the first temperature, which may result in local crystallization, in one embodiment, the temperature difference between the first temperature and the melting point of the phase change material 20 is 10 ℃ to 20 ℃.

In one embodiment, in order to better wrap the phase change material 20 by the matrix 30 and prevent the phase change material 20 from overflowing, the step of mixing the raw materials comprises: the phase change material 20 is first melted to a molten state, the remaining raw materials are then added and mixed, and the matrix material and the cross-linking agent of the remaining raw materials are finally added.

When the matrix material is a polymer material monomer, the polymer material monomer can be polymerized in situ at the first temperature and undergo a curing and crosslinking reaction to form the matrix 30.

Fig. 1 is a schematic structural diagram of a preform according to an embodiment of the present invention, in which the heat conductive fillers 10 are randomly arranged in the preform.

In order to make the heat conductive filler 10 in the preform more easily rotated during the freezing process, and thus to obtain a heat conductive gasket having a better heat dissipation effect, in one embodiment, the thickness of the preform is 0.3mm to 3mm, and more preferably 0.3mm to 2 mm.

In step S3, the second temperature is lower than the melting point of the phase change material 20 and the temperature difference reaches 30 ℃ or higher, so that the preform is rapidly frozen during the freezing process, the heat dissipation direction of the preform is perpendicular to the surface of the preform, and thus the solidification direction of the phase change material 20 is perpendicular to the surface of the preform, so that the heat conductive filler 10 can rotate during the freezing process, and the axial direction of the heat conductive filler 10 forms an angle of 60 degrees to 90 degrees with the heat conductive gasket, and forms a heat conductive path together with the solidified phase change material 20, so that the heat conductive gasket has excellent heat conductivity. It should be noted that when the second temperature is lower than the melting point of the phase change material 20 but the temperature difference is less than 30 ℃, the thermally conductive filler 10 cannot rotate during the freezing process.

In order to further increase the freezing rate of the preform, and to make the thermally conductive filler 10 better rotate, the temperature difference between the second temperature and the melting point of the phase change material 20 is greater than or equal to 50 ℃, and more preferably greater than or equal to 70 ℃.

It should be noted that, if the conditions allow, the temperature difference between the second temperature and the melting point of the phase change material 20 should be as large as possible to increase the freezing speed of the preform.

The preparation method is simple and is suitable for industrial production; and the heat conducting gasket has universality, and heat conducting gaskets with different performances can be obtained by adopting different types of heat conducting fillers 10.

The invention also provides the heat conduction gasket prepared by the preparation method of the heat conduction gasket.

Fig. 2 is a schematic view of a heat conduction gasket according to an embodiment of the present invention, wherein an angle between an axial direction of the heat conduction filler 10 in the heat conduction gasket and a surface of the heat conduction gasket is 60 degrees to 90 degrees.

The invention also provides application of the heat-conducting gasket in electronic products, and particularly provides the heat-conducting gasket as a heat-conducting device in the electronic products.

In one embodiment, the electronic product includes a heat generating device and a heat dissipating device, and preferably, a heat conducting pad is disposed between the heat generating device and the heat dissipating device as a heat conducting device for conducting heat generated by the heat generating device to the heat dissipating device.

The heat conducting gasket provided by the invention has excellent heat conducting performance and high-temperature shape-preserving performance, can be better used as a heat conducting device to be applied to electronic products, can still keep the integrity of the shape even if the temperature is higher than the melting point of the phase-change material 20, and solves the problem of overflow of the phase-change material 20.

Hereinafter, the heat conductive gasket, the method for manufacturing the same, and the application thereof will be further described with reference to the following specific examples.

Example 1

Providing raw materials: 10g of polyethylene glycol (melting point: 63 ℃ C.), 10g of carbon fiber (length: 250 μm), 1.48g of acrylic acid, 0.44g of water, 0.03g of ammonium persulfate and 0.07g of 0.07g N, N' -methylenebisacrylamide.

Melting polyethylene glycol to a molten state at 70 ℃, and then adding the rest raw materials, wherein acrylic acid is added at last to obtain a first mixture; stirring the first mixture at 1000rpm for 2min, mixing, pouring into a mold with a thickness of 1mm, placing the mold in an oven with a temperature of 80 ℃ for heat preservation for 2h, and carrying out in-situ polymerization and curing and crosslinking reaction on acrylic acid completely to obtain a prefabricated product, wherein the crosslinking density is 2.2%.

And (3) freezing the prefabricated product at-24 ℃ for 1min to obtain the heat conduction gasket with the thickness of 1mm, wherein the included angle between the length direction of the carbon fiber and the surface of the heat conduction gasket is 60-90 degrees.

Example 2

Providing raw materials: 10g of polyethylene glycol (melting point: 63 ℃ C.), 5g of carbon fiber (length: 250 μm), 1.48g of acrylic acid, 0.44g of water, 0.03g of ammonium persulfate and 0.07g of 0.07g N, N' -methylenebisacrylamide.

Melting polyethylene glycol to a molten state at 70 ℃, and then adding the rest raw materials, wherein acrylic acid is added at last to obtain a first mixture; stirring the first mixture at 1000rpm for 2min, uniformly mixing, pouring into a mold with the thickness of 1mm, and placing the mold in an oven with the temperature of 80 ℃ for heat preservation for 2h to ensure that the acrylic acid is subjected to in-situ polymerization and then is subjected to curing and crosslinking reaction to completely form polyacrylic rubber, so that a prefabricated product is obtained, wherein the crosslinking density is 2.2%.

And (3) freezing the prefabricated product at-24 ℃ for 1min to obtain the heat conduction gasket with the thickness of 1mm, wherein the included angle between the length direction of the carbon fiber and the surface of the heat conduction gasket is 60-90 degrees.

Example 3

Providing raw materials: 10g of paraffin wax (melting point: 60 ℃ C.), 10g of boron nitride (particle diameter: 10 μm), 3g of silicone oil, 3g of hydrogen silicone oil, and 0.3g of platinum catalyst.

Melting paraffin to a molten state at 80 ℃, and then adding the rest raw materials, wherein a platinum catalyst is added finally to obtain a first mixture; and stirring the first mixture at 1000rpm for 2min, uniformly mixing, pouring into a mold with the thickness of 1mm, placing the mold in an oven with the temperature of 80 ℃ for heat preservation for 12h, and completely curing and crosslinking the silicone oil and the hydrogenated silicone oil to obtain a prefabricated product, wherein the crosslinking density is 0.05%.

And (3) freezing the prefabricated product at-24 ℃ for 1min to obtain the heat conduction gasket with the thickness of 1mm, wherein the included angle between the extension direction of the boron nitride and the surface of the heat conduction gasket is 60-90 degrees.

Example 4

Providing raw materials: 10g of paraffin wax (melting point: 60 ℃ C.), 3g of boron nitride (particle diameter: 10 μm), 3g of silicone oil, 3g of hydrogen silicone oil, and 0.3g of platinum catalyst.

Melting paraffin to a molten state at 80 ℃, and then adding the rest raw materials, wherein a platinum catalyst is added finally to obtain a first mixture; and stirring the first mixture at 1000rpm for 2min, uniformly mixing, pouring into a mold with the thickness of 1mm, placing the mold in an oven with the temperature of 80 ℃ for heat preservation for 12h, and completely curing and crosslinking the silicone oil and the hydrogenated silicone oil to obtain a prefabricated product, wherein the crosslinking density is 0.05%.

And (3) freezing the prefabricated product at-24 ℃ for 1min to obtain the heat conduction gasket with the thickness of 1mm, wherein the included angle between the extension direction of the boron nitride and the surface of the heat conduction gasket is 60-90 degrees.

Example 5

Providing raw materials: 10g of polyethylene glycol (melting point: 63 ℃ C.), 5g of carbon fiber (length: 250 μm), 1.48g of acrylic acid, 0.44g of water, 0.03g of ammonium persulfate and 0.07g of 0.07g N, N' -methylenebisacrylamide.

Melting polyethylene glycol to a molten state at 70 ℃, and then adding the rest raw materials, wherein acrylic acid is added at last to obtain a first mixture; stirring the first mixture at 1000rpm for 2min, uniformly mixing, pouring into a mold with the thickness of 1mm, and placing the mold in an oven with the temperature of 80 ℃ for heat preservation for 2h to ensure that the acrylic acid is subjected to in-situ polymerization and then is subjected to curing and crosslinking reaction to completely form polyacrylic rubber, so that a prefabricated product is obtained, wherein the crosslinking density is 2.2%.

And (3) freezing the prefabricated product at-10 ℃ for 1min to obtain the heat conduction gasket with the thickness of 1mm, wherein the included angle between the length direction of the carbon fiber and the surface of the heat conduction gasket is 60-90 degrees.

Comparative example 1

Providing raw materials: 10g of polyethylene glycol (melting point: 63 ℃ C.), 10g of carbon fiber (length: 250 μm), 1.48g of acrylic acid, 0.44g of water, 0.03g of ammonium persulfate and 0.07g of 0.07g N, N' -methylenebisacrylamide.

Melting polyethylene glycol to a molten state at 70 ℃, and then adding the rest raw materials, wherein acrylic acid is added at last to obtain a first mixture; stirring the first mixture at 1000rpm for 2min, mixing uniformly, pouring into a mold with the thickness of 1mm, placing the mold in an oven with the temperature of 80 ℃ for heat preservation for 2h, and carrying out in-situ polymerization and curing crosslinking reaction on acrylic acid to completely form polyacrylic rubber to obtain a prefabricated product, wherein the crosslinking density is 2.2%.

And cooling the prefabricated product at 35 ℃ for 20min to obtain the heat conduction gasket with the thickness of 1mm, wherein the included angle between the length direction of the carbon fiber and the surface of the heat conduction gasket is 0-90 degrees.

Comparative example 2

Providing raw materials: 10g of paraffin wax (melting point: 60 ℃ C.), 10g of boron nitride (particle diameter: 10 μm), 3g of silicone oil, 3g of hydrogen silicone oil, and 0.3g of platinum catalyst.

Melting paraffin to a molten state at 80 ℃, and then adding the rest raw materials, wherein a platinum catalyst is added finally to obtain a first mixture; and stirring the first mixture at 1000rpm for 2min, uniformly mixing, pouring into a mold with the thickness of 1mm, placing the mold in an oven with the temperature of 80 ℃ for heat preservation for 12h, and completely curing and crosslinking the silicone oil and the hydrogenated silicone oil to obtain a prefabricated product, wherein the crosslinking density is 0.5%.

And cooling the prefabricated product at 35 ℃ for 20min to obtain the heat conducting gasket with the thickness of 1mm, wherein the included angle between the extension direction of the boron nitride and the surface of the heat conducting gasket is 0-90 ℃.

Comparative example 3

Providing raw materials: 10g of polyethylene glycol (melting point: 63 ℃ C.), 10g of carbon fiber (length: 250 μm), 1.48g of acrylic acid, 0.44g of water, 0.03g of ammonium persulfate and 0.07g of 0.07g N, N' -methylenebisacrylamide.

Melting polyethylene glycol to a molten state at 70 ℃, and then adding the rest raw materials, wherein acrylic acid is added at last to obtain a first mixture; stirring the first mixture at 1000rpm for 2min, mixing uniformly, pouring into a mold with the thickness of 5mm, placing the mold in an oven with the temperature of 80 ℃ for heat preservation for 2h, and carrying out in-situ polymerization and curing crosslinking reaction on acrylic acid to completely form polyacrylic rubber to obtain a prefabricated product, wherein the crosslinking density is 2.2%.

And (3) freezing the prefabricated product at-24 ℃ for 1min to obtain the heat conduction gasket with the thickness of 1mm, wherein the included angle between the length direction of the carbon fiber and the surface of the heat conduction gasket is 30-90 degrees.

The longitudinal thermal conductivity, phase transition temperature and phase transition enthalpy of the thermal conductive gaskets manufactured in examples 1 to 5 and comparative examples 1 to 3 were tested, and the test methods and test results are shown in table 1; the method for testing the leakage value comprises the steps of heating the heat-conducting gasket to be above a melting point, weighing after cooling, calculating the mass difference before and after heating, and dividing the mass difference by the mass of the heat-conducting gasket before heating to obtain the leakage value.

TABLE 1

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.