US-12617997-B1 - Method for preparing graphene thermal conductive pad and use thereof

US12617997B1US 12617997 B1US12617997 B1US 12617997B1US-12617997-B1

Abstract

A method for preparing a graphene thermal conductive pad is referred. Graphene foam sheets are used as base materials for the graphene thermal conductive pad. The graphene foam sheets are processed by surface crust removal, laser perforation and edge trimming, plasma activation, and multiple modification treatments to yield the graphene thermal conductive pad. The plasma activation causes the hydroxyl functional groups to be generated on the graphene surface. By using hydroxyvinyl silicone oil diluted with xylene, a small amount of hydroxyvinyl silicone oil uniformly covers the graphene surface. Heating induces dehydration condensation between the hydroxyvinyl silicone oil and the hydroxyl groups generated by plasma activation, forming chemical bonds. In such a way, a tighter interface between the graphene and the subsequent adhesive is achieved, pores at the interface are reduced, thereby lowering thermal contact resistance, improving heat transfer efficiency, and enhancing tensile strength and compression resilience.

Inventors

Jialin WANG
Zhengyang Tang
Donghua Lu
Guanjin Chen
Zipei Li

Assignees

Shenzhen Bornsun New Material Co., Ltd.

Dates

Publication Date: 20260505
Application Date: 20251205
Priority Date: 20250221

Claims (9)

1 . A method for preparing a graphene thermal conductive pad, comprising the following steps: S10, providing a plurality of graphene foam sheets; S20, removing surface crusts from the plurality of graphene foam sheets, performing laser perforation and edge trimming, and plasma activation to obtain activated graphene foam sheets; subjecting the activated graphene foam sheets to a first modification treatment with hydroxyvinyl silicone oil to obtain a plurality of first graphene foam sheets; S30, subjecting the plurality of first graphene foam sheets to a second modification treatment with an adhesive to obtain a plurality of second graphene foam sheets; S40, bonding the plurality of second graphene foam sheets along a thickness direction and pressing into a block, followed by curing, to obtain a third graphene foam sheet; and S50, slicing the third graphene foam sheet along the thickness direction to obtain a graphene thermal conductive pad; wherein the adhesive comprises linear low molecular weight vinyl silicone oil, linear medium molecular weight vinyl silicone oil, linear high molecular weight vinyl silicone oil, a crosslinking agent, a chain extender, a reinforcing agent, a toughening agent, a catalyst, and an inhibitor.
2 . The method for preparing a graphene thermal conductive pad according to claim 1 , wherein in step S10, an average density of the graphene foam sheets is 0.15-0.25 g/cm 3 ; and/or, a thermal diffusivity of the graphene foam sheets is ≥600 mm 2 /s; and/or, a thickness of the graphene foam sheets is 200-300 μm.
3 . The method for preparing a graphene thermal conductive pad according to claim 1 , wherein in step S20, said removing surface crusts comprises: crushing and adhering the surface crusts; and/or, after the laser perforation and edge trimming, an average aperture of perforations is 10-200 μm, and a distance between the perforations is 100-4000 μm; and/or, the plasma activation comprises using a direct injection plasma activation equipment; and/or, the first modification treatment comprises coating the activated graphene foam sheets with hydroxyvinyl silicone oil diluted with xylene, and after complete absorption, performing vacuum heat treatment to obtain the plurality of first graphene foam sheets, wherein the coating comprises spraying 3-9 mg of hydroxyvinyl silicone oil per square centimeter of the activated graphene foam sheets.
4 . The method for preparing a graphene thermal conductive pad according to claim 1 , wherein in step S30, the second modification treatment comprises spraying the adhesive onto the plurality of first graphene foam sheets and mixing to obtain the plurality of second graphene foam sheets, wherein the spraying comprises spraying 70-110 mg of the adhesive per square centimeter of the first graphene foam sheets.
5 . The method for preparing a graphene thermal conductive pad according to claim 4 , wherein the linear low molecular weight vinyl silicone oil is 50 cP vinyl silicone oil, the linear medium molecular weight vinyl silicone oil is 500 cP vinyl silicone oil, and the linear high molecular weight vinyl silicone oil is 20,000 cP vinyl silicone oil; wherein a mass ratio of the 50 cP vinyl silicone oil, the 500 cP vinyl silicone oil, the 20,000 cP vinyl silicone oil, the chain extender, the crosslinking agent, the reinforcing agent, the toughening agent, the catalyst, and the inhibitor is (20-50):(60-130):(30-50):(15-25):(20-30):(3-5):(0.5-1.5):(0.3-0.6):(0.08-0.12); and/or, a mass ratio of the first graphene foam sheets to the adhesive is 1:(1-3).
6 . The method for preparing a graphene thermal conductive pad according to claim 5 , wherein in the adhesive, the linear low molecular weight vinyl silicone oil comprises low molecular weight silicone oil with a viscosity of 500 cP or less; and/or, the linear medium molecular weight vinyl silicone oil comprises medium molecular weight silicone oil with a viscosity of 500-5000 cP; and/or, the linear high molecular weight vinyl silicone oil comprises high molecular weight silicone oil with a viscosity above 5000 cP; and/or, the crosslinking agent comprises side-hydrogen silicone oil; and/or, the chain extender comprises end-hydrogen silicone oil; and/or, the reinforcing agent comprises MQ resin; and/or, the toughening agent comprises nano-grade fumed silica; and/or, the catalyst comprises a platinum catalyst; and/or, the inhibitor comprises an alkyne alcohol inhibitor.
7 . The method for preparing a graphene thermal conductive pad according to claim 5 , wherein preparation steps of the adhesive comprise: mixing the linear low molecular weight vinyl silicone oil, the linear medium molecular weight vinyl silicone oil, the linear high molecular weight vinyl silicone oil, the crosslinking agent, the chain extender, the catalyst, the inhibitor, the reinforcing agent, and the toughening agent.
8 . The method for preparing a graphene thermal conductive pad according to claim 1 , wherein in step S40, a thickness of the third graphene foam sheet is 40-50 mm; and/or, in step S50, a thickness of the graphene thermal conductive pad is 0.3-2.0 mm.
9 . A graphene thermal conductive pad, prepared by the method for preparing a graphene thermal conductive pad according to claim 1 .

Description

CROSS-REFERENCE TO RELATED APPLICATION The present application claims priority from Chinese Patent Application No.: 202510194880.9 filed on Feb. 21, 2025, the contents of which are incorporated herein by reference in their entirety. FIELD OF THE INVENTION The present invention relates to the technical field of graphene thermal conduction, and particularly to a method for preparing a graphene thermal conductive pad and use thereof. BACKGROUND OF THE INVENTION A graphene thermal conductive pad is a thermal interface material used to improve heat conduction between electronic components and heat sinks. The graphene thermal conductive pad is prepared from graphene, which is a single layer of carbon atoms arranged in a honeycomb lattice, possessing exceptional thermal conductivity. Typically, it is a thin and flexible sheet placed between a heat-generating component (e.g., a CPU) and a heat sink, rapidly transferring heat from the component to the heat sink. Therefore, the graphene thermal conductive pad is widely applicable in electronic devices. Thermal Interface Materials (TIMs) are commonly used in IC packaging and electronic heat dissipation, and primarily fill micro-gaps and surface irregularities generated when two materials are joined or contacted, thereby reducing contact thermal resistance and enhancing the heat dissipation performance of the device. Heat transfer at the interface typically employs thin, flexible sheets placed between the heat-generating component (e.g., a CPU) and the heat sink. These sheets exhibit high thermal conductivity along with good compressibility and resilience, enabling rapid heat transfer from the component to the heat sink, and thus find broad application scenarios in electronic devices. Currently, the thermal interface materials with high thermal conductivity include liquid metals (40-50 W/(m·K)) and thermal greases (below 10 W/(m·K)). However, liquid metals tend to corrode the contacted metal surfaces, and since heat sinks are primarily made of aluminum substrates, stable long-term contact cannot be maintained. Thermal greases not only have insufficient thermal conductivity but also suffer from the volatilization of low molecular weight silicone oil during long-term use, leading to drying and cracking of the gel, which rapidly increases interfacial thermal resistance. Therefore, there is an urgent need for a thermal conductive pad with superior performance. SUMMARY OF THE INVENTION The primary objective of the present invention is to provide a method for preparing a graphene thermal conductive pad and use thereof, aiming to enhance the strength of the graphene thermal conductive pad while maintaining both thermal conductivity and resilience. To achieve the above objective, the present invention provides a method for preparing a graphene thermal conductive pad, including the following steps: S10, providing a plurality of graphene foam sheets;S20, removing surface crusts from the plurality of graphene foam sheets, performing laser perforation and edge trimming, and plasma activation to obtain activated graphene foam sheets; subjecting the activated graphene foam sheets to a first modification treatment with hydroxyvinyl silicone oil to obtain a plurality of first graphene foam sheets;S30, subjecting the plurality of first graphene foam sheets to a second modification treatment with an adhesive to obtain a plurality of second graphene foam sheets;S40, bonding the plurality of second graphene foam sheets along a thickness direction and pressing into a block, followed by curing, to obtain a third graphene foam sheet; andS50, slicing the third graphene foam sheet along the thickness direction to obtain a graphene thermal conductive pad; wherein the adhesive includes linear low molecular weight vinyl silicone oil, linear medium molecular weight vinyl silicone oil, linear high molecular weight vinyl silicone oil, a crosslinking agent, a chain extender, a reinforcing agent, a toughening agent, a catalyst, and an inhibitor. As an embodiment, in step S10, an average density of the graphene foam sheets is 0.15-0.25 g/cm3. As an embodiment, a thermal diffusivity of the graphene foam sheets is ≥600 mm2/s. As an embodiment, a thickness of the graphene foam sheets is 200-300 μm. As an embodiment, in step S20, said removing surface crusts includes crushing and adhering the surface crusts. As an embodiment, after the laser perforation and edge trimming, an average aperture of perforations is 10-200 μm, and a distance between the perforations is 100-4000 μm. As an embodiment, the plasma activation includes using a direct injection plasma activation equipment. As an embodiment, the first modification treatment includes coating the activated graphene foam sheets with hydroxyvinyl silicone oil diluted with xylene, and after complete absorption, performing vacuum heat treatment to obtain the plurality of first graphene foam sheets, wherein the coating includes spraying 3-9 mg of hydroxyvinyl