Thermally conductive silicone sheet is a thermally conductive dielectric material synthesized by a special process, also known as thermally conductive silicone pad, thermally conductive silicone film, soft thermally conductive pad, thermally conductive silicone gasket, etc. In the industry, it is specially produced for the design of gap heat transfer, it can fill the gap, complete the heat transfer between the heating part and the heat dissipation part, and also play the role of insulation, shock absorption and sealing, and can meet small and ultra-thin device design.
The production process of thermal conductive silicone sheet mainly includes raw material preparation, molding vulcanization, edge cutting, plasticizing, mixing, inspection, etc. The following is a brief introduction to the production process of thermal silica gel sheets:
1. The thermal conductivity of ordinary silicone rubber is usually only about 0.2w/mK, but adding thermal conductive fillers to ordinary silicone rubber can improve its thermal conductivity. Commonly used thermally conductive fillers include metal oxides and metal nitrides. The thermal conductivity of the filler is not only related to the material itself, but also closely related to the particle size distribution, shape, interface contact, and degree of intramolecular bonding. In general, fibrous or foil thermally conductive fillers conduct heat better.
2. Plastering, plasticizing, and mixing are a process of silica gel processing, which refers to the use of chemical or mechanical methods to reduce the molecular weight and viscosity of raw rubber, so that its plasticity will be improved and suitable fluidity can be obtained to meet the requirements of molding and Mixing needs, further processing. The raw material of thermal silica gel sheets is usually destroyed by mechanical high-speed stirring. After color matching, the fragments of various colors are replaced by milky white silicone.
3. Molding vulcanization If you want to make a soft, elastic and stretchable thermally conductive silicone sheet, you need to vulcanize the organic silica gel twice. Vulcanization can actually be called curing. The cross-linking density of liquid heat-conducting silica gel is not enough after one-stage heating and molding. Only through further vulcanization reaction, the resilience, hardness, tensile strength, swelling degree, density and thermal stability of heat-conducting silica gel sheet can be greatly improved compared with one-time vulcanization. improve. The performance of the thermally conductive silicone sheet produced will be affected to a certain extent. If the secondary vulcanization is not carried out, products with better performance may not be produced. The product parameters after primary vulcanization are different from those after secondary vulcanization, which is related to the actual operation process and steps.
The thermally conductive silicone sheet after high temperature treatment needs to be placed for a period of time. After natural cooling, it can be cut into different sizes and specifications. Other rapid cooling methods cannot be used, otherwise the product performance of the thermally conductive silicone sheet will be directly affected. The main items of finished product testing include: thermal conductivity, volume resistivity, pressure resistance, flame retardancy, temperature range, tensile strength, hardness, thickness, etc.
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