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CN-121991412-A - Graphene composite heat-conducting filler and preparation method and application thereof

CN121991412ACN 121991412 ACN121991412 ACN 121991412ACN-121991412-A

Abstract

The invention relates to the technical field of heat conduction gel, in particular to a graphene composite heat conduction filler and a preparation method and application thereof. The specific surface area of the conventional commercially available graphene exceeds 200m 2 /g, the oil absorption is large, a rich heat conduction network is difficult to form in the heat conduction gel, and the heat conduction property of the graphene cannot be well exerted by directly using the graphene as the heat conduction filler of the heat conduction gel. Aiming at the problems, the invention provides a graphene composite heat-conducting filler, which is formed by compounding large-particle-size irregular micrometer silicon (60-100 mu m), small-size irregular micrometer silicon carbide (10-20 mu m) and graphene coated spherical nanometer silicon (< 1 mu m) in a heat-conducting gel material system, wherein a richer three-dimensional heat-conducting network is formed in the heat-conducting gel material system, the graphene coated spherical nanometer silicon is filled in gaps formed by the irregular micrometer silicon and the silicon carbide, and the gaps are mutually overlapped and mutually cooperated, the obtained heat-conducting gel has higher heat conductivity coefficient and extrusion rate, the density of the heat-conducting gel is only 1.8-2.3 g/cm 3 , the heat conductivity coefficient is up to 12-18W/(m.K), and the extrusion rate is over 100 g/min.

Inventors

  • HE DAFANG

Assignees

  • 常州新达方创新材料科技有限公司

Dates

Publication Date
20260508
Application Date
20241102

Claims (10)

  1. 1. The graphene composite heat-conducting filler is characterized by comprising a heat-conducting filler, wherein long-chain alkyl siloxane is uniformly sprayed on the surface of the heat-conducting filler in an atomized form to obtain the graphene composite heat-conducting filler, and the mass ratio of the heat-conducting filler to the long-chain alkyl siloxane is 100:0.5-5; The heat conduction filler comprises large-particle-size irregular micron silicon, small-particle-size irregular micron silicon carbide and graphene coated spherical nano silicon; The graphene coated spherical nano silicon comprises spherical nano silicon and a graphene coating uniformly covered on the surface of the spherical nano silicon, wherein the graphene coating is prepared by uniformly dispersing the spherical nano silicon in graphene oxide dispersion liquid, and then obtaining uniform and continuous graphene coating on the surface of the spherical nano silicon in a spray drying mode.
  2. 2. The graphene composite heat-conducting filler according to claim 1, wherein the heat-conducting filler is obtained by uniformly mixing large-particle-size irregular micron silicon, small-particle-size irregular micron silicon carbide and graphene-coated spherical nano silicon in a jet mill through multi-strand high-pressure air flow blowing collision, the air flow pressure is 0.5-2.0 MPa, and the air blowing time is 30-120 min.
  3. 3. The graphene composite heat-conducting filler according to claim 2, wherein the mass ratio of the large-particle-size irregular micron silicon to the small-particle-size irregular micron silicon carbide to the graphene-coated spherical nano silicon is 5-8:2-5:0.5-1.
  4. 4. The graphene composite heat-conducting filler according to claim 2, wherein the average particle sizes of the large-particle-size irregular micrometer silicon and the small-particle-size irregular nanometer silicon carbide are respectively 60-100 μm and 10-20 μm, and the average particle size of the graphene-coated spherical nanometer silicon is 200-1000 nm.
  5. 5. The graphene composite heat-conducting filler according to claim 1, wherein the mass concentration of the graphene oxide dispersion liquid is 1-30 g/L, and the mass ratio of the spherical nano-silicon to the graphene oxide dispersion liquid is 1-5:1.
  6. 6. The graphene composite heat-conducting filler according to claim 1, wherein the average particle size of the spherical nano-silicon is 100-500 nm.
  7. 7. The graphene composite heat-conducting filler according to claim 1, wherein graphene oxide in the graphene oxide dispersion liquid is a single layer, and the average particle size is 1-5 μm.
  8. 8. The graphene composite thermally conductive filler of claim 1, wherein the atomization temperature is 100-300 ℃.
  9. 9. The graphene composite heat-conducting filler according to claim 1, wherein the structural formula of the long-chain alkyl siloxane is CH 3 (CH 2 ) n SiX 3 , wherein n is 6-18, and X is at least one of methoxy and ethoxy.
  10. 10. The heat-conducting gel is characterized by comprising side chain hydrogen-containing silicone oil, end group hydrogen-containing silicone oil, vinyl silicone oil, an inhibitor, a platinum catalyst and a heat-conducting filler, wherein the heat-conducting filler is the graphene composite heat-conducting filler according to any one of claims 1-9, and the mass ratio of the vinyl silicone oil to the side chain hydrogen-containing silicone oil, the end group hydrogen-containing silicone oil, the inhibitor, the platinum catalyst to the heat-conducting filler is 100:1-4:10-40:0.1-0.3:0.01-0.05:1800-2800.

Description

Graphene composite heat-conducting filler and preparation method and application thereof Technical Field The invention relates to the technical field of heat conduction gel, in particular to a graphene composite heat conduction filler and a preparation method and application thereof. Background As electronic devices have been miniaturized, multifunctional, and high-performance, power density has been rapidly increased, and heat generation has been rapidly increased. During the heat dissipation of electronic devices, heat needs to be transferred from the device interior to the device packaging material, the heat sink, and then to the external environment. However, the roughness of the solid surface on a microscopic scale is uneven, even if the contact pressure of the two solid surfaces is as high as 10 MPa, the actual contact area only accounts for 1-2% of the apparent contact area, the rest is the micro-pores filled with air, and the heat conductivity coefficient of the air is only 0.025W/(m·k)), which seriously hinders the heat generated inside the electronic device from being conducted to the heat sink. In order to reduce the interfacial thermal resistance, thermally conductive gels have been developed. The heat conducting gel is filled between the contact surfaces, so that air in the pores of the contact interface can be discharged, a continuous heat conducting channel is formed on the whole contact interface, and the heat radiating efficiency is improved. The current mainstream technology is to fill spherical aluminum nitride, silicon carbide, aluminum oxide, zinc oxide, simple substance aluminum and the like into a silicone oil matrix of the heat conduction gel as heat conduction fillers, so that spherical particles can form a good heat conduction network in the gel with more addition, and the heat conduction coefficient of the heat conduction gel obtained by the current technology is difficult to exceed 8W/(m.K). In addition, conventional heat-conducting fillers such as aluminum nitride, silicon carbide, aluminum oxide, zinc oxide, elemental aluminum and the like have higher intrinsic densities, generally exceeding 3 g/cm 3, and excessive filling amounts can lead to high density, high viscosity, low extrusion rate and poor subsequent use convenience of the heat-conducting gel. The thermal conductivity of the graphene is as high as 5300W/(m.K), the graphene is a material with the best known thermal conductivity, the ultrathin characteristic of the graphene endows the graphene with extremely low specific gravity, and the density of the graphene is far less than that of main stream thermal conductive fillers such as aluminum nitride, silicon carbide, aluminum oxide, zinc oxide and the like. At present, a report is also made on graphene-based heat conduction filler, but the specific surface area of commercial two-dimensional graphene exceeds 200 m 2/g, and a large amount of silicone oil can be adsorbed by the large specific surface area, so that the filling rate of graphene in organic silicon is low, a rich heat conduction network is difficult to form, the extrusion rate of heat conduction gel is low, the hardness is high, and the application requirement is difficult to meet. Disclosure of Invention The prior art has the problems that the specific surface area of the conventional graphene sold on the market exceeds 200 m 2/g, the oil absorption is large, a rich heat conduction network is difficult to form in the heat conduction gel, and the heat conduction property of the graphene cannot be well exerted when the graphene is directly used as the heat conduction filler of the heat conduction gel. Aiming at the problems, the invention provides a graphene composite heat-conducting filler, which comprises a heat-conducting filler, wherein long-chain alkyl siloxane is uniformly sprayed on the surface of the heat-conducting filler in an atomized form to obtain the graphene composite heat-conducting filler, and the mass ratio of the heat-conducting filler to the long-chain alkyl siloxane is 100:0.5-5; The heat conduction filler comprises large-particle-size irregular micron silicon, small-particle-size irregular micron silicon carbide and graphene coated spherical nano silicon; The graphene coated spherical nano silicon comprises spherical nano silicon and a graphene coating uniformly covered on the surface of the spherical nano silicon, wherein the graphene coating is prepared by uniformly dispersing the spherical nano silicon in graphene oxide dispersion liquid, and then obtaining a continuous graphene coating on the surface of the spherical nano silicon in a spray drying mode. Preferably, the heat conducting filler is prepared by uniformly mixing large-particle-size irregular micron silicon, small-particle-size irregular micron silicon carbide and graphene coated spherical nano silicon in an airflow pulverizer through multi-strand high-pressure airflow blowing and collision, wherein the airflow pressure is 0.5