CN113560146A - Longitudinal high-thermal-conductivity gasket, preparation method and application - Google Patents

Abstract

The invention provides a method for preparing a longitudinal high-thermal-conductivity gasket, which comprises the following steps: uniformly mixing materials to obtain a mixed material, wherein the materials comprise a binder, an anisotropic heat-conducting filler and an optional isotropic heat-conducting filler; coating the mixed material on the surface of a base material to obtain a coating on the surface of the base material; treating the obtained coating to a semi-vulcanization state to obtain a semi-vulcanization state coating; coating the mixed material on the obtained semi-vulcanized coating again; and repeating the steps of semi-fluidization and coating for multiple times, vulcanizing and molding the coating, and slicing the coating along the direction vertical to the coating to obtain the longitudinal high-thermal-conductivity gasket. The invention also provides a longitudinal high-thermal-conductivity gasket and application thereof. The invention realizes the directional arrangement of the anisotropic heat-conducting filler in the matrix binder, has simple and easy preparation process, is easy to realize large-scale continuous production, effectively eliminates bubbles and further improves the heat-conducting property of the material.

Description

Longitudinal high-thermal-conductivity gasket, preparation method and application

Technical Field

The invention belongs to the technical field of heat conduction and heat dissipation, and relates to a longitudinal high-heat-conductivity gasket, a preparation method and application.

Background

The existing longitudinal high-thermal-conductivity gasket mainly comprises the following steps: extrusion, magnetic field orientation, electrostatic flocking. The principle of the extrusion method is that anisotropic heat-conducting fillers (such as carbon fibers) are directionally arranged along the flowing direction of fluid in the process of extruding materials by an extruder; and stacking, hot-pressing, vulcanizing and slicing the extruded materials to obtain the longitudinal high-thermal-conductivity gasket. In the method, the material is extruded through a slit, the thickness of the material is generally not more than 5mm, and therefore the extruded material needs to be stacked and pressed for forming. The process steps are complex, and a large gap exists during stacking, so that a cavity is easily formed in the pressed material; meanwhile, due to the fusion of the gaps, overflow in pressing and other reasons, the orientation of the heat-conducting filler in the material is easy to change. In addition, since the stacking is performed by compression molding, it is difficult to prepare a large-area high thermal conductive gasket.

The principle of the magnetic field orientation method is that the magnetic field is ultra-strong (such as>10T) anisotropic heat conductive filler (such as carbon fiber) is oriented along the magnetic field direction, thereby obtaining the longitudinal high heat conductive gasket. Because the heat-conducting filler has high filling amount in the matrix glue (such as>80 wt.%), resulting in a material with a high viscosity (e.g., high viscosity>10⁶mPa s) required for the ultra-large superconducting magnet to form a steady magnetic field, and is not conducive to continuous production due to the extremely complicated equipment design, extremely strict requirements and extremely high cost. In addition, the size of the inner cavity of the steady-state super-strong magnetic field device is generally small (less than 300mm), and the method is difficult to prepare the high-heat-conductivity gasket with a large area.

The principle of the electrostatic flocking method is that anisotropic heat-conducting fillers (such as carbon fibers) are directionally flocked on primer through an ultra-strong electric field, and anisotropic heat-conducting seasonings are immersed through liquid-phase impregnation, so that the longitudinal high-heat-conducting gasket is finally obtained. The superstrong electric field requires multiple coating-flocking-dipping-vulcanizing cycles, the process is complex, the directionality of anisotropic fillers during flocking is difficult to control, the solution used for dipping needs to have fluidity, the filling amount is greatly reduced, and partial bubbles can not be effectively removed in the dipping process, so that the adverse factors finally influence the heat conduction effect of the product.

Disclosure of Invention

In view of one or more of the problems of the prior art, according to an aspect of the present invention, there is provided a method for manufacturing a longitudinal high thermal conductive gasket, including:

step 1) uniformly mixing materials to obtain a mixed material, wherein the material comprises a binder and an anisotropic heat-conducting filler;

step 2) coating the mixed material on the surface of a base material to obtain a coating on the surface of the base material;

step 3) treating the coating obtained in the step 2) to a semi-vulcanized state to obtain a semi-vulcanized coating; step 4) coating the mixed material on the semi-vulcanized coating obtained in the step 3) again;

and 5) repeating the step 3) and the step 4) for multiple times, vulcanizing and forming the coating, and slicing along the direction perpendicular to the coating to obtain the longitudinal high-thermal-conductivity gasket.

In one embodiment, in step 1), the binder is one or a mixture of several of epoxy resin, phenolic resin, furfural resin, polyurethane, acrylic resin and organic silica gel;

preferably, the binder adopts organic silica gel;

further preferably, the adhesive is one or a mixture of more of polydimethylsiloxane, alpha, omega-dihydroxy polydimethylsiloxane, polydiphenylsiloxane, alpha, omega-dihydroxy polymethyl (3,3, 3-trifluoropropyl) siloxane, cyanosiloxysilane, and alpha, omega-diethyl polydimethylsiloxane.

In one embodiment, in the step 1), the anisotropic thermal conductive filler includes at least one of carbon fiber, graphene, graphite, carbon nanotube, carbon nanofiber, carbon microfiber, and boron nitride;

preferably, the anisotropic heat conductive filler is surface-treated; the surface treatment is chemical treatment or physical treatment; the chemical treatment comprises at least one of acidification, oxidation, basification, nitration, sulfonation, epoxidation, hydrogenation, and metalation; the physical treatment comprises at least one of coating and wrapping;

further preferably, the content of the anisotropic heat conductive filler in the mixture is 20 wt.% to 60 wt.%; more preferably 30-40 wt.%;

further preferably, the thermal conductivity of the carbon fiber is more than or equal to 300W/(m K); the length of the carbon fiber is 50-500 μm; more preferably 100-300 μm; the diameter of the carbon fiber is 5-30 μm; more preferably 7-15 μm;

further preferably, the thermal conductivity of the graphene is more than or equal to 300W/(m K); the sheet diameter of the graphene is 1-500 mu m; more preferably 5 to 200 μm;

further preferably, the thermal conductivity of the graphite sheet is more than or equal to 300W/(m K); the sheet diameter is 30-500 μm; more preferably 50-300 μm;

further preferably, the thermal conductivity of the boron nitride is more than or equal to 100W/(m K); the sheet diameter is 5-500 μm, preferably 10-200 μm.

In one embodiment, the mass further comprises an isotropic thermally conductive filler;

preferably, the isotropic heat conducting filler comprises at least one of aluminum oxide, aluminum nitride and silicon carbide;

preferably, the particle size of the isotropic thermally conductive filler is 0.1 to 150 μm, and further preferably, 5 to 50 μm;

preferably, the content of the isotropic thermally conductive filler in the mixture is 20 wt.% to 60 wt.%, further preferably 30 wt.% to 40 wt.%.

In one embodiment, the total content of the anisotropic heat-conducting filler and the isotropic filler is taken as the total filler content; the total content of the filler in the longitudinal high thermal conductivity gasket is 40-80 wt.%, preferably 50-70 wt.%.

In one embodiment, in the step 2), the coating manner is preferably blade coating;

the coating speed is 0.1-2 m/min; preferably 0.5-1.5 m/min;

the thickness of each coating is 0.1-2 mm; preferably 0.5-1.5 mm; the width is not particularly limited, and is preferably 100-200 mm.

In one embodiment, in the step 3), the method of treatment of the coating is heating;

in the heating method, the temperature is 50-80 ℃, and preferably 60 ℃; the time is 1-10min, preferably 3-5 min;

in the step 4), the coating conditions are the same as those in the step 2);

in the step 5), the temperature is 100-200 ℃, and preferably 150 ℃; the time is 30-90 min.

The invention also provides the longitudinal high-thermal-conductivity gasket prepared by the preparation method.

In one embodiment, the longitudinal high thermal conductivity gasket comprises a base material and a vulcanization molded coating coated on the base material, wherein the coating comprises a binder and anisotropic thermal conductive filler.

The kind of the binder is not particularly limited, and may be a thermosetting resin, a thermoplastic resin, an elastomer, etc. in one embodiment, and is selected as needed.

The content of the binder is not particularly limited, and is preferably 10% to 60% by weight, more preferably 20% to 50% by weight.

The thermosetting resin can be one or more of epoxy resin, phenolic resin, organic silicon resin, polyurethane, polyimide resin, unsaturated polyester, polymethylsiloxane, maleic amide resin, thermosetting polyphenyl ether, melamine formaldehyde resin, furfural phenol resin, furfural acetone resin, furfuryl alcohol resin, polybutadiene resin, urea formaldehyde resin, diallyl phthalate resin and other crosslinking resins.

The thermoplastic resin may be one or a mixture of polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamide, polyoxymethylene, polycarbonate, polyphenylene oxide, polysulfone, rubber, an ethylene-olefin copolymer, polyvinylidene chloride, polymethylpentene, polyvinyl alcohol, polyacetal, polyvinyl acetate, polyvinylidene fluoride, polytetrafluoroethylene, an ABS resin, a styrene-acrylonitrile copolymer, or the like.

The thermoplastic elastomer may be one or a mixture of more of styrene elastomer, olefin elastomer, diene elastomer, vinyl chloride elastomer, polyurethane elastomer, etc.

Among the above-mentioned binder materials, thermosetting resins are preferable, and thermosetting silicone resins are more preferable, from the viewpoints of temperature resistance, processability, mechanical elasticity, and affinity for electronic components and compatibility.

The silicone resin is not particularly limited, and may be a one-component condensed silicone rubber, a one-component addition type two-component silicone rubber, a two-component condensed silicone rubber, or a two-component addition type silicone rubber. As a material for a heat-dissipating gasket for an electronic device, an addition type silicone rubber is preferably selected from the viewpoint of adhesion to the surfaces of an electronic component and a heat sink and reduction in thermal resistance. The addition type organic silicon rubber is preferably double-group addition type silicon rubber, wherein the double components are vinyl-containing polysiloxane and Si-H-containing polysiloxane respectively, and the proper mixing proportion can be selected according to the performances of elasticity, hardness and the like of the high-heat-conduction gasket.

In one embodiment, the anisotropic thermally conductive filler comprises one or a mixture of carbon fibers, graphene, graphite, carbon nanotubes, carbon nanofibers, carbon microfibers, boron nitride, and the like.

The carbon fiber can be obtained by spinning, carbonizing and graphitizing pitch, polyacrylonitrile and the like, can also be prepared by hydrocarbon such as methane, ethylene, ethanol, benzene and the like and hydrocarbon derivatives through a chemical vapor deposition method, and even can be prepared by methods such as arc discharge and the like. The carbon fiber used is preferably a mesophase pitch-based carbon fiber from the viewpoint of obtaining high thermal conductivity. The length of the carbon fiber is preferably 5 to 500 μm, more preferably 50 to 300 μm; the diameter is preferably 5 to 30 μm, more preferably 7 to 15 μm.

The surface treatment of the carbon fiber is not particularly limited, and chemical treatments such as acidification, oxidation, basification, nitration, sulfonation, epoxidation, hydrogenation, metallization, and the like may be performed as necessary; physical methods such as coating and wrapping may be performed.

The content of the carbon fibers in the longitudinal high thermal conductivity spacer is not particularly limited, and is preferably 20 wt.% to 60 wt.%, more preferably 20 wt.% to 50 wt.%, and most preferably 25 wt.% to 40 wt.%.

Graphene can be obtained by a preparation method such as a mechanical exfoliation method, a vapor deposition method, a redox method, an epitaxial growth method, and the like. The graphene prepared by a mechanical stripping method is preferably selected from the heat conduction effect of the prepared graphene, the simplicity and the environmental friendliness of the preparation method. The sheet diameter of the graphene is not particularly limited, and is preferably 1 to 500. mu.m, more preferably 5 to 200. mu.m, and most preferably 50 to 150. mu.m. The number of graphene layers is not particularly limited and may be 1 to 10 layers, preferably 1 to 5 layers, and more preferably 1 to 3 layers.

The surface treatment of graphene is not particularly limited, and chemical treatments such as acidification, oxidation, basification, nitration, sulfonation, epoxidation, hydrogenation, metallization, and the like may be performed as needed; physical methods such as coating and wrapping may be performed.

The content of the graphene is not particularly limited, and is preferably 20 wt.% to 60 wt.%, more preferably 25 wt.% to 50 wt.%, and most preferably 30 wt.% to 40 wt.%.

The graphite sheet can be ordinary graphite sheet, graphitized graphite sheet, and expanded graphite sheet. The flake diameter of the graphite flake is not particularly limited, but is preferably 1 to 500. mu.m, more preferably 5 to 200. mu.m, most preferably 50 to 150. mu.m. The thickness of the graphite sheet is not particularly limited, but is preferably 0.01 to 100. mu.m, more preferably 1 to 50 μm, and most preferably 5 to 30 μm.

The surface treatment of the graphite sheet is not particularly limited, and chemical treatments such as acidification, oxidation, basification, nitration, sulfonation, epoxidation, hydrogenation, metallization, and the like may be performed as necessary; physical methods such as coating and wrapping may be performed.

The content of the graphite flakes is not particularly limited, and is preferably 20 wt.% to 60 wt.%, more preferably 25 wt.% to 50 wt.%, and most preferably 30 wt.% to 40 wt.%.

The carbon nanotubes may be prepared by arc discharge, chemical vapor deposition, or the like. The carbon nanotubes prepared by chemical vapor deposition are preferred from the aspects of yield, performance and the like. The carbon nanotubes may be single-walled carbon nanotubes, multi-walled carbon nanotubes, or a mixture of both.

The surface treatment of the carbon nanotube is not particularly limited, and may be carried out by chemical treatments such as acidification, oxidation, basification, nitration, sulfonation, epoxidation, hydrogenation, metallization, and the like, as required; physical methods such as coating and wrapping may be performed.

The length of the carbon nanotube is not particularly limited, and is preferably 10 to 500 μm, more preferably 15 to 300 μm, and most preferably 20 to 200 μm; the diameter is not particularly limited, but is preferably 2 to 200nm, more preferably 10 to 150nm, most preferably 20 to 60 nm.

The content of the carbon nanotubes is not particularly limited, and is preferably 20 wt.% to 60 wt.%, more preferably 25 wt.% to 50 wt.%, and most preferably 30 wt.% to 40 wt.%.

The carbon nanofibers can be made by arc discharge, carbonization of organic fibers, chemical vapor deposition, and the like. The carbon nanotubes prepared by chemical vapor deposition are preferred from the aspects of yield, performance and the like. The carbon nanofiber can be one or a mixture of several of plate-shaped carbon nanofiber, fishbone-shaped carbon nanofiber and tubular carbon nanofiber.

The surface treatment of the carbon nanofibers is not particularly limited, and chemical treatments such as acidification, oxidation, basification, nitration, sulfonation, epoxidation, hydrogenation, metallization, and the like may be performed as needed; physical methods such as coating and wrapping may be performed.

The length of the carbon nanofiber is not particularly limited, and is preferably 10 to 300 μm, more preferably 20 to 250 μm, and most preferably 50 to 200 μm; the diameter is not particularly limited, and is preferably 10 to 990nm, more preferably 100-600nm, and most preferably 200-500 nm.

The content of the carbon nanofibers is not particularly limited, and is preferably 20 wt.% to 60 wt.%, more preferably 25 wt.% to 50 wt.%, and most preferably 30 wt.% to 40 wt.%.

The carbon nanotube can be prepared by template method, chemical vapor deposition method, carbon nanotube wall-increasing method, etc. The carbon micron tube is prepared by a chemical vapor deposition method or a high-orientation carbon nano tube wall-increasing method in consideration of yield, mechanical property, heat conductivity and the like.

The length of the carbon micro-tube is not particularly limited, preferably 10-500 μm, more preferably 15-300 μm, and most preferably 20-200 μm; the diameter is not particularly limited, but is preferably 2 to 30 μm, more preferably 3 to 25 μm, and most preferably 5 to 20 μm.

The surface treatment of the carbon nanotube is not particularly limited, and may be performed by chemical treatments such as acidification, oxidation, basification, nitration, sulfonation, epoxidation, hydrogenation, metallization, and the like, as required; physical methods such as coating and wrapping may be performed.

The content of the carbon nanotube is not particularly limited, and is preferably 20 wt.% to 60 wt.%, more preferably 25 wt.% to 50 wt.%, and most preferably 30 wt.% to 40 wt.%.

In view of the thermal conductivity and anisotropy, hexagonal boron nitride is preferred as the type of boron nitride. The sheet diameter of the boron nitride is not particularly required, and is preferably 0.05 to 500. mu.m, more preferably 10 to 300. mu.m, and most preferably 50 to 200. mu.m.

The content of boron nitride is not particularly limited, and is preferably 20 wt.% to 60 wt.%, more preferably 25 wt.% to 50 wt.%, and most preferably 30 wt.% to 40 wt.%.

In one embodiment, the mass of the coating further comprises an isotropic thermally conductive filler.

The isotropic heat conducting filler contains one or more of alumina, aluminum nitride, silicon carbide and the like. The shapes of the aluminum oxide, the aluminum nitride and the silicon carbide are not particularly limited, and can be spherical, spheroidal, polyhedral or a mixture of the spherical, the spheroidal, the polyhedral or the mixture of the spherical, the spheroidal and the polyhedral.

The particle size of the alumina is 100nm-200 μm, preferably 1-100 μm, and most preferably 5-50 μm. The content of alumina is not particularly limited, and is preferably 20 wt.% to 60 wt.%, more preferably 25 wt.% to 60 wt.%, and most preferably 30 wt.% to 50 wt.%.

The particle size of the aluminum nitride is 50nm-200 μm, preferably 1-100 μm, and most preferably 5-50 μm. The content of aluminum nitride is not particularly limited, and is preferably 20 wt.% to 60 wt.%, more preferably 25 wt.% to 60 wt.%, and most preferably 30 wt.% to 50 wt.%.

The particle size of the silicon carbide is 100nm-200 μm, preferably 1-100 μm, and most preferably 5-50 μm. The content of silicon carbide is not particularly limited, and is preferably 20 wt.% to 60 wt.%, more preferably 25 wt.% to 60 wt.%, and most preferably 30 wt.% to 50 wt.%.

In one embodiment, the total filler content is the sum of the contents of the anisotropic thermal conductive filler and the isotropic filler in the longitudinal high thermal conductive gasket. The total content of the filler is not particularly limited, and is preferably 20 wt.% to 80 wt.%, more preferably 25 wt.% to 75 wt.%, and most preferably 30 wt.% to 70 wt.%.

The invention also provides application of the longitudinal high-thermal-conductivity gasket in heat conduction.

The invention also provides application of the longitudinal high-thermal-conductivity gasket in preparation of a thermal-conductivity product.

The invention can effectively realize the directional distribution of the anisotropic heat-conducting filler in the matrix binder; the method is simple and feasible, high in degree of continuity, low in preparation cost and suitable for large-scale production; the coating thickness can be controlled by the coating times, and the longitudinal high-heat-conductivity gasket with a larger area can be prepared; bubbles can be effectively removed in the coating process, and the heat conductivity coefficient of the material is effectively improved; and a semi-vulcanization mode is adopted, so that the formed material is not easy to layer.

Drawings

Fig. 1 is a schematic view of a method for manufacturing a longitudinal high thermal conductivity gasket according to the present invention.

Detailed Description

In the following, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

The present invention will be further illustrated with reference to the following specific examples, but the present invention is not limited to the following examples. The method is a conventional method unless otherwise specified. The starting materials are commercially available from the open literature unless otherwise specified.

Fig. 1 is a schematic view of a method for manufacturing a longitudinal high thermal conductivity gasket according to the present invention, as shown in fig. 1, the method includes:

mixing materials, namely uniformly mixing the materials to obtain a mixed material, wherein the materials comprise a binder, an anisotropic heat-conducting filler and an optional isotropic heat-conducting filler;

coating and semi-curing, namely coating the mixed material on the surface of a base material to obtain a coating on the surface of the base material, and treating (heating or/and standing) the coating to a semi-cured (semi-vulcanized) state to obtain a semi-cured (semi-vulcanized) coating;

repeating coating and semi-curing, coating the mixed material on the semi-cured coating again, and repeating the semi-curing and coating for multiple times until the thickness of the coating reaches the thickness requirement;

curing and molding (vulcanization molding) of the multilayer coating;

and (4) slicing, namely slicing along the direction perpendicular to the coating direction to obtain the longitudinal high-thermal-conductivity gasket.

The invention adopts a simple coating method to realize the directional arrangement of the anisotropic heat-conducting filler in the matrix adhesive; meanwhile, a formed body with controllable thickness is obtained through repeated coating processes for many times, and the heat conducting pad material with high longitudinal heat conducting performance is obtained through slicing in the thickness direction. The preparation process is simple and easy to implement, and large-scale continuous production is easy to realize; and bubbles are effectively removed in the preparation process, so that the heat-conducting property of the material is further improved.

For comparison, the cut thickness is unified to be 2mm, the thermal conductivity and the application thermal resistance of the thermal conductive gasket under the condition of 20psi are tested according to the method of ASTM D5470, and the compression resilience of the thermal conductive gasket under the condition of 50% strain is tested according to the method of ASTM D575.

Example 1

In this embodiment, the binder: polydimethylsiloxane, content 40 wt.%,

anisotropic heat conductive filler: carbon fiber, content 60 wt.%, length 300 μm, diameter 15 μm,

coating rate: 1.5m/min, and the reaction temperature is 1.5m/min,

the thickness of each coating is 1.5mm, the width is 200mm,

heating: the temperature is 80 ℃, the time is 3min,

and (3) vulcanization: the temperature is 150 ℃, the time is 30min,

through tests, the application thermal resistance of the longitudinal high-thermal-conductivity gasket obtained in the embodiment is 1.42W-cm²K, thermal conductivity of 17.75W/(m.K), and compression resilience of 92%.

Example 2

In this embodiment, the binder: polydimethylsiloxane, content 30 wt.%,

anisotropic heat conductive filler: carbon fiber, content 40 wt.%, length 100 μm, diameter 10 μm,

isotropic thermally conductive filler: alumina, content 30 wt.%, particle size 100 μm,

coating rate: the concentration of the mixture is 0.5m/min,

the thickness of each coating is 0.5mm, the width is 100mm,

heating: the temperature is 60 ℃, the time is 5min,

and (3) vulcanization: the temperature is 100 ℃, the time is 90min,

through tests, the application thermal resistance of the longitudinal high-thermal-conductivity gasket obtained in the embodiment is 2.03W-cm²K, thermal conductivity coefficient 11.34W/(m.K), and compression resilience 87%.

Example 3

In this example, the adhesive was alpha, omega-dihydroxy polydimethylsiloxane, at a level of 50 wt.%,

anisotropic heat conductive filler: 30 wt.% of graphene, a sheet diameter of 150 μm,

isotropic thermally conductive filler: aluminum nitride, content 20 wt.%, particle size 10 μm,

coating rate: 2m/min, and the reaction temperature is 2m/min,

the thickness of each coating is 2mm, the width is 150mm,

heating: the temperature is 60 ℃, the time is 5min,

and (3) vulcanization: the temperature is 100 ℃, the time is 90min,

through tests, the application thermal resistance of the longitudinal high-thermal-conductivity gasket obtained in the embodiment is 2.08W cm²K, thermal conductivity coefficient 8.21W/(m.K), compression resilience 83%.

Example 4

In the present example, the adhesive was polydiphenylsiloxane, at a 20 wt.% level,

anisotropic heat conductive filler: graphene, content 20 wt.%, sheet diameter 100 μm,

isotropic thermally conductive filler: silicon carbide, content 60 wt.%, particle size 50 μm,

coating rate: the concentration of the mixture is 0.1m/min,

the thickness of each coating is 0.1mm, the width is 120mm,

heating: the temperature is 50 ℃, the time is 10min,

and (3) vulcanization: the temperature is 200 ℃, the time is 30min,

through tests, the application thermal resistance of the longitudinal high-thermal-conductivity gasket obtained in the embodiment is 2.92W-cm²K, thermal conductivity of 5.45W/(m.K), and compression resilience of 77%.

Example 5

In this example, the adhesive was alpha, omega-dihydroxypolymethyl (3,3, 3-trifluoropropyl) siloxane, at a 20 wt.% content,

anisotropic heat conductive filler: boron nitride with a content of 60 wt.%, a wafer diameter of 50 μm,

isotropic thermally conductive filler: aluminum nitride, content 20 wt.%, particle size 5 μm,

coating rate: 1m/min of the total weight of the mixture,

the thickness of each coating is 1mm, the width is 150mm,

heating: the temperature is 70 ℃, the time is 6min,

and (3) vulcanization: the temperature is 120 ℃, the time is 60min,

tests prove that the longitudinal high-thermal-conductivity gasket obtained in the embodiment has the advantages ofThe thermal resistance is 1.38 W.cm²K, thermal conductivity coefficient 12.34W/(m.K), compression resilience 71%.

Example 6

In this example, the adhesive was 40 wt.% cyanosiloxysilane,

anisotropic heat conductive filler 1: 30 wt.% of graphene, 5 μm in sheet diameter,

anisotropic heat conductive filler 2: 30 wt.% of graphite flakes, 30 μm in flake diameter,

coating rate: 1.2m/min, and the reaction temperature is 1.2m/min,

the thickness of each coating is 1mm, the width is 140mm,

heating: the temperature is 75 ℃, the time is 5min,

and (3) vulcanization: the temperature is 180 ℃, the time is 75min,

through tests, the application thermal resistance of the longitudinal high-thermal-conductivity gasket obtained in the embodiment is 2.72W-cm²K, thermal conductivity of 7.63W/(m.K), and compression resilience of 76%.

Example 7

In the present embodiment, the first and second electrodes are,

adhesive 1: alpha, omega-diethylpolydimethylsiloxane, content 10 wt.%,

adhesive 2: cyanosiloxysilane, content 10 wt.%,

anisotropic heat conductive filler: boron nitride with a content of 60 wt.%, a wafer diameter of 50 μm,

isotropic thermally conductive filler: alumina, content 20 wt.%, particle size 50 μm,

coating rate: 1m/min of the total weight of the mixture,

the thickness of each coating is 1mm, the width is 120mm,

heating: the temperature is 80 ℃, the time is 3min,

and (3) vulcanization: the temperature is 120 ℃, the time is 60min,

through tests, the application thermal resistance of the longitudinal high-thermal-conductivity gasket obtained in the embodiment is 1.43W-cm²K, thermal conductivity 13.55W/(m.K), compression resilience 82%.

The invention adopts a simple coating method, and realizes the directional arrangement of anisotropic heat-conducting fillers in the matrix binder by utilizing the interaction of a coating scraper and material fluid; repeatedly coating for many times when the coated coating is in a semi-vulcanized state; and finally vulcanizing the material after multiple coatings, and slicing the material along the direction perpendicular to the coating direction to obtain the longitudinal high-thermal-conductivity gasket.

As described above, according to the embodiments of the present invention, various changes and modifications can be made by those skilled in the art without departing from the scope of the technical idea of the present invention. The technical scope of the present invention is not limited to the contents of the specification, and must be determined according to the scope of the claims.

Claims (10)

1. A method for preparing a longitudinal high-thermal-conductivity gasket is characterized by comprising the following steps: the method comprises the following steps:

1) uniformly mixing materials to obtain a mixed material, wherein the material comprises a binder and an anisotropic heat-conducting filler;

2) coating the mixed material on the surface of a base material to obtain a coating on the surface of the base material;

3) treating the coating obtained in the step 2) to a semi-vulcanization state to obtain a semi-vulcanization state coating;

4) coating the mixed material on the coating in the semi-vulcanized state obtained in the step 3) again;

5) and repeating the step 3) and the step 4) for multiple times, vulcanizing and forming the coating, and slicing along the direction perpendicular to the coating to obtain the longitudinal high-thermal-conductivity gasket.

2. The method of claim 1, wherein: in the step 1), the binder is one or a mixture of more of epoxy resin, phenolic resin, furfural resin, polyurethane, acrylic resin and organic silica gel;

preferably, the binder adopts organic silica gel;

further preferably, the adhesive is one or a mixture of more of polydimethylsiloxane, alpha, omega-dihydroxy polydimethylsiloxane, polydiphenylsiloxane, alpha, omega-dihydroxy polymethyl (3,3, 3-trifluoropropyl) siloxane, cyanosiloxysilane, and alpha, omega-diethyl polydimethylsiloxane.

3. The method according to claim 1 or 2, characterized in that: in the step 1), the anisotropic heat-conducting filler comprises at least one of carbon fiber, graphene, graphite, carbon nanotubes, carbon nanofibers, carbon microfibers and boron nitride;

preferably, the anisotropic heat conductive filler is subjected to surface treatment; the surface treatment is chemical treatment or physical treatment; the chemical treatment comprises at least one of acidification, oxidation, basification, nitration, sulfonation, epoxidation, hydrogenation, and metalation; the physical treatment comprises at least one of coating and wrapping;

further preferably, the content of the anisotropic heat conductive filler in the mixture is 20 wt.% to 60 wt.%; more preferably 30-40 wt.%;

further preferably, the thermal conductivity of the carbon fiber is more than or equal to 300W/(m K); the length of the carbon fiber is 50-500 μm; more preferably 100-300 μm; the diameter of the carbon fiber is 5-30 μm; more preferably 7-15 μm;

further preferably, the thermal conductivity of the graphene is more than or equal to 300W/(m K); the sheet diameter of the graphene is 1-500 mu m; more preferably 5 to 200 μm;

further preferably, the thermal conductivity of the graphite sheet is more than or equal to 300W/(m K); the sheet diameter is 30-500 μm; more preferably 50-300 μm;

further preferably, the thermal conductivity of the boron nitride is more than or equal to 100W/(m K); the sheet diameter is 5-500 μm, preferably 10-200 μm.

4. A method according to any one of claims 1 to 3, wherein: the material also comprises isotropic heat-conducting filler;

preferably, the isotropic heat conducting filler comprises at least one of aluminum oxide, aluminum nitride and silicon carbide;

preferably, the particle size of the isotropic heat-conducting filler is 0.1-150 μm, and further preferably, the particle size of the isotropic heat-conducting filler is 5-50 μm;

preferably, the content of the isotropic heat-conducting filler in the mixture is 20 wt.% to 60 wt.%, and further preferably, the content of the isotropic heat-conducting filler in the mixture is 30 wt.% to 40 wt.%.

5. The method according to any one of claims 1 to 4, wherein: the total content of the anisotropic heat conduction filler and the isotropic filler is taken as the total content of the filler; the total content of the filler in the longitudinal high thermal conductivity gasket is 40 wt.% to 80 wt.%, and preferably, the total content of the filler in the longitudinal high thermal conductivity gasket is 50 wt.% to 70 wt.%.

6. The method according to any one of claims 1 to 5, wherein: in the step 2), the coating mode is preferably blade coating;

the coating speed is 0.1-2 m/min; preferably, the coating speed is 0.5-1.5 m/min;

the thickness of each coating is 0.1-2 mm; preferably, the thickness of each coating is 0.5-1.5 mm; the width is not particularly limited, and preferably, the width per coating is 100-200 mm.

7. The method according to any one of claims 1 to 6, wherein: in the step 3), the coating is treated by heating;

in the heating, the temperature is 50-80 ℃, and preferably 60 ℃; the time is 1-10min, preferably 3-5 min;

in the step 4), the coating conditions are the same as those in the step 2);

in the step 5), the temperature is 100-200 ℃, and preferably 150 ℃; the time is 30-90 min.

8. Longitudinal high thermal conductivity gasket prepared by the method of any one of claims 1 to 7.

9. Use of the longitudinal high thermal conductivity gasket of claim 8 for thermal conduction.

10. Use of the longitudinal high thermal conductivity gasket according to claim 8 for the preparation of a thermally conductive product.

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