The crosslinking agent includes side-hydrogen silicone oil; and/or, the chain extender includes end-hydrogen silicone oil; and/or, the reinforcing agent includes MQ resin; and/or, the toughening agent includes nano-grade fumed silica.

In some embodiments of the present invention, the preparation steps of the adhesive include 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.

In some embodiments of the present invention, in step S40, the thickness of the third graphene foam sheet is 40-50 mm, which can be flexibly adjusted according to testing requirements.

In some embodiments of the present invention, in step S50, the thickness of the graphene thermal conductive pad is 0.3-2.0 mm. This range ensures the full utilization of the inherent high thermal conductivity of graphene, thereby allowing heat to be rapidly transferred from the heat source to the heat sink or other cooling devices, and improving the overall heat exchange efficiency of the system. At the same time, it can adapt to contact surfaces of different shapes and sizes, ensuring good conformity, reducing air gaps, and thereby lowering thermal resistance.

The present invention also provides a graphene thermal conductive pad which is prepared by the method for preparing a graphene thermal conductive pad as described above. The graphene thermal conductive pad possesses all the beneficial effects of the aforementioned preparation method, which will not be reiterated here.

The technical solutions of the present invention are further described in detail below in conjunction with specific examples. It should be understood that the following examples are merely intended to explain the present invention and not to limit the present invention.

Experimental Materials

Hydroxyvinyl silicone oil was sourced from Zhejiang Zhenghe Silicon Material Co., Ltd., model 207V-2.5.

The following silicone oils were all sourced from Anbiya Specialty Silicones (Nantong) Co., Ltd., only the specific models are listed below:

- 50 cP vinyl silicone oil, model VS 50;
- 500 cP vinyl silicone oil, model VS 500;
- 20,000 cP vinyl silicone oil, model VS 20000;
- 0.2% end-hydrogen silicone oil, model CE 100;
- 0.34% side-hydrogen silicone oil, model XL 12.
- MQ resin was sourced from Kangda Technology, model VMQ-2709.
- Nano-grade fumed silica was sourced from Hubei Huifu Nanomaterial Co., Ltd., model HB139.

Example 1

A method for preparing a graphene thermal conductive pad includes the following steps:

- S10: Providing 43 graphene foam sheets with a thermal diffusivity of 650 mm²/s, a density of 0.2 g/cm³, and dimensions of 100*100*350 mm (length*width*height);
- S20: Adsorbing the 43 graphene foam sheets onto a surface using a vacuum table, and using a laser perforation machine, specifically setting a 1500 W power laser focused 2 mm above the graphene surface, forming an effective circle with a diameter of 1 mm, and scanning rapidly at 10 mm/s; pasting a bonding area as wide as the graphene foam sheets on a roller press with a diameter of 300 mm, adjusting the gap between the double rollers to match the thickness of the graphene foam sheets, then feeding the graphene foam sheets from one side to perform surface crust removal on partial areas; and repeating the operation to remove the crusts from the entire surface of all graphene foam sheets, thereby obtaining 43 first graphene foam sheets with the hardened surface crusts removed, having a thickness of 300 μm (±15 μm);
- S30: Performing laser perforation and edge trimming on the 43 first graphene foam sheets; specifically, placing the 43 first graphene foam sheets on a laser perforation platform, simultaneously performing laser perforation and edge trimming operations. The aperture is 50 μm, the perforation pitch is 1000 μm, with upper and lower rows staggered by 1000 μm in an A/B/A/B repeating pattern. The edge trimming size is 50 mm*50 mm to facilitate subsequent plasma activation.

The specific treatment for the plasma activation is as follows: placing the samples in a plate frame with a grid, and using a direct injection plasma activation equipment, with setting the power to 800 W, the horizontal height of the spray gun from the sample to 10 mm, and the spray gun nozzle size to a circle with a diameter of 10 mm. Using the projection method, the calculated effective treatment area is a circle with a diameter of 20 mm, so the moving speed of the spray gun is 5 mm/s, moving down 20 mm when changing lines. A “Z”-shaped path is set to perform plasma activation over the entire surface, thereby obtaining activated graphene foam sheets.

The treatment further includes evenly spraying the activated graphene foam sheets with hydroxyvinyl silicone oil diluted 10 times with xylene using a spraying machine, and controlling the spraying amount to 6 mg/cm². After the hydroxyvinyl silicone oil is fully absorbed, 43 first graphene foam sheets are obtained. Then the 43 first graphene foam sheets are subjected to a second modification treatment with an adhesive. The specific treatment includes spraying the adhesive onto the plurality of first graphene foam sheets and mixing to obtain a plurality of second graphene foam sheets, and controlling the spraying amount to 90 mg of adhesive per square centimeter of the first graphene foam sheet. That is, 43*4=172 second graphene foam sheets with dimensions of 50*50 mm are obtained.

S40: Placing the 172 second graphene foam sheets in a mold, stacking them together; after stacking all 172 sheets, placing a square aluminum block of 50*50*5 mm on the top and bottom, using an automatic pushing device to apply a certain pressure on the aluminum blocks, making the graphene foam sheets closely adhere to each other; locking the aluminum blocks when the overall distance between them is 51.6 mm; and placing the entire device in an oven and heat at 120° C. for 2 hours for curing, thereby obtaining a third graphene foam sheet;

S50: Removing the third graphene foam sheet from the oven, taking it out from the module, cutting off the surface residual adhesive with a knife, and placing it on the operating table of a diamond cutting machine; then setting the cutting thickness to 300 μm and slicing along the thickness direction to obtain a graphene thermal conductive pad.

Specifically, the specific components and dosages of the adhesive are as follows: 20 parts of 50 cP vinyl silicone oil, 100 parts of 500 cP vinyl silicone oil, 30 parts of 20,000 cP vinyl silicone oil, 20 parts of 0.2% end-hydrogen silicone oil, 25 parts of 0.34% side-hydrogen silicone oil, 4 parts of MQ resin, 1 part of nano-grade fumed silica, 0.5 parts of 5000 ppm platinum catalyst, and 0.1 part of alkyne alcohol inhibitor.