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CN-122011775-A - Graphene composite heat-conducting gasket and preparation method thereof

CN122011775ACN 122011775 ACN122011775 ACN 122011775ACN-122011775-A

Abstract

The invention discloses a graphene composite heat-conducting gasket and a preparation method thereof, wherein the gasket comprises 30-45 parts of a three-dimensional graphene heat-conducting foam film skeleton, 40-60 parts of modified heat-conducting filler, 2-5 parts of an interface bridging agent, 25-35 parts of a two-component adhesive, 8-15 parts of a curing agent and 1-3 parts of an auxiliary agent, wherein the three-dimensional graphene heat-conducting foam film is subjected to laser drilling treatment, the aperture is 0.5-2mm, the porosity is 60-75%, the modified heat-conducting filler is boron nitride and/or aluminum oxide of which the surface is coated with a core-shell oxide layer, the core layer is TiO 2 with the thickness of 5-10nm, the shell layer is a silane coupling agent derivative with the grafting rate of 2.5-3.0%, the interface bridging agent is Ti 3 C 2 TX nano-sheets, and the two-component adhesive consists of organic silicon resin and epoxy resin according to the weight ratio of 1:0.3-0.8. The invention solves the technical problems of insufficient heat conduction performance and large interface contact thermal resistance of the traditional heat conduction gasket, and is mainly used for heat conduction and heat dissipation of electronic devices.

Inventors

  • CHEN JIE
  • ZHANG HUAN

Assignees

  • 深圳市飞荣达科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260206

Claims (10)

  1. 1. The graphene composite heat-conducting gasket is characterized by comprising the following raw materials, by weight, 30-45 parts of a three-dimensional graphene heat-conducting foam film skeleton, 40-60 parts of modified heat-conducting filler, 2-5 parts of an interface bridging agent, 25-35 parts of a two-component adhesive, 8-15 parts of a curing agent and 1-3 parts of an auxiliary agent; the modified heat conducting filler is boron nitride and/or aluminum oxide with a surface coated with a core-shell oxide layer, the core layer is TiO 2 with the thickness of 5-10nm, and the shell layer is a silane coupling agent derivative with the grafting rate of 2.5-3.0%.
  2. 2. The graphene composite heat-conducting gasket of claim 1, wherein the interface bridging agent is Ti 3 C 2 T X nano-sheets, the thickness is 2-5nm, the transverse dimension is 0.5-2 μm, and the surface zeta potential is-30 to-40 mV.
  3. 3. The graphene composite heat-conducting gasket according to claim 2, wherein the interface bridging agent is prepared by mixing Ti 3 AlC 2 MAX phase raw materials with ZnCl 2 according to a molar ratio of 1:1.5-1.8, burning at 600-650 ℃ for 4-6h under argon atmosphere, ultrasonically washing with 0.1-0.2mol/L hydrochloric acid for 30-45min to remove ZnCl 2 , washing with deionized water to pH=6-7, adding 8-12mL tetrabutylammonium hydroxide and 8-12mL tetramethylammonium hydroxide into each 0.2g crude product, stirring at 40+ -2 ℃ for 12-16h, performing intercalation treatment, diluting with deionized water according to a volume ratio of 1:400-500, ultrasonically stripping at 300-400W for 6-8h under ice bath condition of 15 ℃ or less, vacuum filtering, and vacuum drying at 50+ -5 ℃ for 12h to obtain lamellar MXes nanosheets.
  4. 4. The graphene composite heat-conducting gasket according to claim 1 is characterized in that the two-component adhesive consists of organic silicon resin and epoxy resin according to a weight ratio of 1:0.3-0.8, wherein the organic silicon resin is vinyl-terminated polydimethylsiloxane, the viscosity is 5000-8000 mPa.s, the epoxy resin is bisphenol A type epoxy resin E-44 or E-51, and the epoxy value is 0.41-0.53 eq/100g.
  5. 5. The graphene composite heat-conducting gasket of claim 1, wherein the auxiliary agent is a thixotropic agent and a leveling agent.
  6. 6. The graphene composite heat-conducting gasket according to claim 1, wherein the modified heat-conducting filler is prepared by the following method: S1.1, pretreating a heat conducting filler, namely vacuum drying spherical alumina and/or hexagonal boron nitride at 120 ℃ for 4-6 hours, and removing surface adsorption moisture; S1.2, coating a TiO 2 nuclear layer, namely dispersing a dried heat-conducting filler in a mixed solution of absolute ethyl alcohol and deionized water, wherein the volume ratio of the ethyl alcohol to the deionized water is 2:1, the solid-to-liquid ratio is 1g:15-20mL, performing ultrasonic dispersion for 30-40min, the stirring speed is 300-400rpm, then dropwise adding an ethanol solution of tetrabutyl titanate, the dosage of which is 8-12% of the mass of the heat-conducting filler, the dropwise adding speed is 2-3mL/min, simultaneously dropwise adding ammonia water with the mass fraction of 25% to adjust the pH value of a system to 8.8-9.2, controlling the reaction temperature to 60+/-2 ℃, continuously stirring for 2-3h, hydrolyzing and condensing the tetrabutyl titanate to form TiO 2 sol and coating the TiO 2 sol on the surface of the filler, filling the suspension into a dialysis bag with the cut-off molecular weight of 1000-1200 after the reaction is finished, dialyzing the deionized water for 48-72h until the conductivity of the dialysis liquid is less than 5 mu S/cm, removing residual ions, and performing vacuum drying at 80 ℃ for 12h, calcining at 500 ℃ for 2h to obtain a modified nuclear layer filler with the TiO 2 coating thickness of 5-10 nm; S1.3, performing core layer hydrophobic modification, namely dispersing core layer modified filler in absolute ethyl alcohol, adding zinc stearate with a solid-liquid ratio of 1g to 10mL, performing surface hydrophobic modification, wherein the zinc stearate is 10-15% of the mass of a TiO 2 core layer, performing oil bath reflux reaction for 4 hours at 80 ℃, stirring at 200-300rpm, performing centrifugal washing after the reaction is finished, adopting mixed liquid with ethanol and deionized water in a volume ratio of 1:1 to wash for 3 times, performing centrifugal rotation at 4000-5000rpm each time for 10 minutes, performing vacuum drying on the washed product at 80 ℃ for 6 hours, and calcining the washed product in a muffle furnace at 500 ℃ for 3 hours to obtain the hydrophobic core layer modified filler; S1.4, grafting an organic siloxane shell, namely dispersing a hydrophobic core layer modified filler in isopropanol, wherein the solid-to-liquid ratio is 1g to 20mL, carrying out ultrasonic dispersion for 30min, the frequency is 35-45kHz, the power is 400-450W, adding KH-570 serving as a silane coupling agent, wherein the dosage of KH-570 is 6-9% of the mass of the core layer modified filler, stirring for 30min at room temperature to fully hydrolyze, then dropwise adding an isopropanol solution of aluminum isopropoxide, the concentration is 0.2mol/L, the dosage is 3-5% of the mass of the core layer modified filler, the dropwise adding rate is 1-2mL/min, heating to 70-80 ℃, continuously stirring and reacting for 5-6h, enabling the silane coupling agent to form a siloxane network on the surface of the filler, carrying out reduced pressure filtration after the reaction is completed, washing for 2 times by isopropanol, and carrying out vacuum drying for 12h at 60 ℃, thus obtaining the core-shell structure modified heat conducting filler, wherein the grafting rate of the organic siloxane shell is 2.5-3.0wt% and the shell thickness is 5-10nm.
  7. 7. The graphene composite heat-conducting gasket according to claim 2, wherein the modified heat-conducting filler and the interface bridging agent form a composite filler through electrostatic self-assembly: S2.1, modifying the surface charge of a modified heat-conducting filler, namely dispersing the modified heat-conducting filler in a mixed solution of ethanol and deionized water, wherein the volume ratio of the ethanol to the deionized water is 1:1, the solid-to-liquid ratio is 1g:80-120mL, the ultrasonic dispersion is carried out for 30-40min, the ultrasonic power is 200-300W, the frequency is 40kHz, a filler suspension is obtained, dissolving KH550 in the deionized water, the dosage of KH550 is 2.5-4.0% of the mass of the modified heat-conducting filler, the dosage of the deionized water is 4-6 times of the mass of KH550, dropwise adding glacial acetic acid to adjust the pH to 3.5-4.0, stirring at room temperature for 15-20min to fully hydrolyze KH550, slowly dropwise adding the hydrolyzed KH550 solution into the filler suspension, dropwise adding the solution to the speed of 3-5mL/min, heating to 75-85 ℃, continuously stirring the solution for reaction for 3.5-4.5h, washing the deionized water for 3-4 times, and carrying out vacuum drying for 80-90 ℃ for 8-12h, thus obtaining the modified filler with positive charges on the surface; S2.2, preparing an interface bridging agent dispersion liquid, namely dispersing the interface bridging agent in deionized water, preparing an interface bridging agent aqueous dispersion liquid with the concentration of 1.5-2.5mg/mL, performing ultrasonic dispersion for 1-1.5h, controlling the ultrasonic power to be 200-250W, controlling the temperature to be 10-15 ℃, and performing magnetic stirring for 2-3h at the stirring rotating speed of 300-400rpm to obtain a stably dispersed interface bridging agent dispersion liquid; S2.3, electrostatic self-assembly, namely slowly dripping the interface bridging agent dispersion liquid obtained in the step S2.2 into the modified filler dispersion liquid with positive charges on the surface obtained in the step S2.1 at the dripping rate of 1-2mL/min under the condition of room temperature, wherein the solid content of the modified filler dispersion liquid is 15-25mg/mL, the mass ratio of the interface bridging agent to the modified heat-conducting filler is 1:12-20, continuously magnetically stirring in the dripping process, the stirring rotating speed is 280-350rpm, continuously stirring for 4-6h after the dripping is finished, standing for 30-45min to fully carry out electrostatic adsorption, and vacuum filtering the obtained suspension liquid and vacuum drying for 10-14h at 50-60 ℃ to obtain the composite filler.
  8. 8. The preparation method of the graphene composite heat-conducting gasket according to claim 7, which is characterized by comprising the following steps: S31, preprocessing a three-dimensional graphene heat-conducting foam film, namely cutting the graphene foam film prepared by a chemical vapor deposition method into a shape, adopting a laser drilling technology to prepare through holes with the aperture of 0.5-2mm and the hole spacing of 3-5mm, controlling the porosity to be 60-75%, then soaking the punched foam film in an ethanol solution containing 4-6wt% Ti (OC 4 H 9 ) 4 ), hydrolyzing for 4 hours at 80 ℃, forming a TiO 2 nuclear layer with the thickness of 5-8nm on the surface of a graphene skeleton, carrying out reflux modification for 4-5 hours at 80 ℃ by using a 0.1mol/L zinc stearate ethanol solution, and finally grafting a shell layer by using methacryloxypropyl trimethoxysilane to obtain a core-shell modified graphene foam skeleton; s32, preparing a two-component adhesive, namely mixing the organic silicon resin and the epoxy resin according to the weight ratio of 1:0.3-0.8, vacuum defoaming for 2 hours at 80 ℃, adding an auxiliary agent, and uniformly stirring; S33, dipping and composite molding, namely placing the three-dimensional graphene foam film pretreated in the step S1 into a mold, vacuumizing to-0.09 MPa, and injecting the adhesive and the composite filler in the step S32, wherein the filling amount of the composite filler is 60-75% of the mass of the adhesive, and the dipping time is 30-60min; s34, hot-press molding, namely hot-press curing the impregnated foam film for 1-3 hours under the conditions of the pressure of 5-15MPa and the temperature of 80-120 ℃, then curing for 2-4 hours after 80-100 ℃, and cooling to room temperature; S35, performing surface treatment, namely performing double-sided polishing treatment on the formed gasket, wherein the surface roughness Ra is less than or equal to 0.8 mu m, and the thickness tolerance is controlled to be +/-0.05 mm, so that the graphene composite heat-conducting gasket is obtained.
  9. 9. The graphene composite heat-conducting gasket according to claim 8, wherein in the step S31, the laser drilling holes are distributed in a hexagonal array, the hole diameters are 0.8-1.2mm, and the hole walls are subjected to plasma treatment to increase the roughness so as to enhance the mechanical engagement with the adhesive.
  10. 10. The graphene composite heat-conducting gasket according to claim 8, wherein the dipping process in the step S33 is a vacuum-pressure circulation process, wherein the dipping process is performed by vacuumizing to-0.095 MPa for 30min, then applying a pressure of 0.3-0.5MPa for 20min, and circulating for 2-3 times to ensure that the adhesive fully fills the foam film pores.

Description

Graphene composite heat-conducting gasket and preparation method thereof Technical Field The invention relates to the field of heat conducting materials, in particular to a graphene composite heat conducting gasket and a preparation method thereof. Background With the continuous increase of the power density of electronic equipment and the increasingly strict heat dissipation requirements, the performance of the heat-conducting interface material serving as a key component of a thermal management system directly influences the working stability and the service life of electronic devices. Graphene is an ideal material for preparing high-performance heat-conducting gaskets due to the excellent intrinsic heat-conducting property (the theoretical heat-conducting coefficient can reach 5300W/(m.K)). At present, the preparation technology of the graphene heat-conducting gasket mainly comprises methods of graphene film lamination and compounding, graphene filler blending, three-dimensional graphene network construction and the like. Chinese patent CN108913104a discloses a thermal conductive gasket and a method for preparing the same, which adopts a three-dimensional membranous graphene network structure, prepares a graphene skeleton in ordered arrangement by a template method, and refills an insulating thermal conductive filler and a silica gel matrix. Chinese patent CN112375392a discloses a preparation method of a graphene thermal interface material, which utilizes graphene oxide composite thermal conductive filler and silicone oil system to be compounded, and improves thermal conductivity through reduction treatment. Chinese patent CN112341819B proposes a method for preparing an insulating graphene heat-conducting gasket, which combines a modified insulating filler with graphene oxide by using an electrostatic self-assembly technology to form a hybrid heat-conducting filler. Chinese patent CN115092920B describes a graphene heat conductive gasket and a method for preparing the same, by laminating and bonding graphene composite films and heat conductive filler composite layers, cutting into thin sheets along the lamination direction. Chinese patent CN114148044B discloses a graphene composite heat-conducting gasket and a preparation method thereof, wherein the graphene heat-conducting foam film is subjected to laser drilling treatment, and the composite gasket is prepared by adhesive impregnation and lamination stacking. However, the existing graphene heat conduction gasket technology still has a plurality of technical defects that firstly, the surface energy difference between graphene and a polymer matrix is large, the interface bonding property is poor, the interface thermal resistance is high, the scattering is serious in the phonon transmission process, the overall heat conduction performance of a composite material is seriously restricted, secondly, the contact thermal resistance between graphene sheets is large, a continuous and effective three-dimensional heat conduction network is difficult to form, a heat conduction path is incomplete, the intrinsic heat conduction advantage of the graphene cannot be fully exerted, and secondly, the brittleness of a pure graphene film is large, the problem that the compression rebound resilience is insufficient exists in a simple blending type gasket, the mechanical performance is difficult to meet the actual application requirement, and furthermore, the resin viscosity is rapidly increased under a high filling rate, the process compatibility is poor, the full impregnation is difficult to realize, and the product quality stability is influenced. The heat conductivity of the existing product is limited to 80-150W/(m.K), the interface modification means is single, the double requirements of ultra-high heat conductivity and excellent mechanical property are difficult to meet at the same time, and a new technical scheme is needed to be developed to solve the problems. Disclosure of Invention The graphene composite heat-conducting gasket is provided for solving the technical problems of high interface thermal resistance, discontinuous heat-conducting channels, poor mechanical property, poor process compatibility and the like of the conventional graphene heat-conducting gasket, and realizing ultrahigh heat-conducting property, extremely low interface thermal resistance, excellent mechanical property, process feasibility and long-term stability. The graphene composite heat-conducting gasket is realized by the following technical scheme that the graphene composite heat-conducting gasket comprises, by weight, 30-45 parts of a three-dimensional graphene heat-conducting foam film skeleton, 40-60 parts of modified heat-conducting filler, 2-5 parts of interface bridging agent, 25-35 parts of two-component adhesive, 8-15 parts of curing agent and 1-3 parts of auxiliary agent; the modified heat conducting filler is boron nitride and/or aluminum oxide with a surface coated with a core-she