The production process of thermal conductive silica pad mainly includes:
raw material preparation → plastic refining and mixing → molding and vulcanization → trimming and cutting → inspection.
The following is a brief introduction to the production process of thermal silicone pad:
1. Raw material preparation
The thermal conductivity of ordinary organic silica gel is only about 0.2 W/m · K. However, the thermal conductivity of silica gel can be improved by mixing thermal conductive fillers in ordinary silica gel. The commonly used thermal conductive fillers are metal oxides (such as Al2O3, MgO, BeO, etc.) and metal nitrides (such as sin, AlN, BN, etc.). The thermal conductivity of fillers is not only related to the material itself, but also closely related to the particle size distribution, morphology, interfacial contact, and the degree of binding within molecules. Generally speaking, the thermal conductivity of fibrous or foil fillers is better.
2. Molding and mixing
Plasticizing and mixing is a process of silica gel processing. It refers to the use of mechanical or chemical methods to reduce the molecular weight and viscosity of raw rubber to improve its plasticity and obtain appropriate fluidity to meet the needs of further processing of mixing and molding. The raw material of thermal conductive silicone pad is usually destroyed by mechanical high-speed stirring. After color matching and mixing, the Milky silica gel is changed into various color sheets.
3. Molding vulcanization
If you want to make a soft, elastic and stretch resistant thermal conductive silicone pad, you need to use the secondary vulcanized organic silica gel. Vulcanization can also be called curing. The crosslinking density of the liquid thermal conductive silica gel is not enough after the first stage heating. The tensile strength, spring back, hardness, swelling degree, density and thermal stability of the thermal conductive silicone pad can be increased only by further vulcanization. If the secondary vulcanization is not carried out, the performance of the thermal silicone pad may be affected to some extent, and no better product can be obtained. The product parameters after primary vulcanization are different from those of secondary vulcanization, which is also related to the actual operation process and steps.
4. Trim and cut
After high temperature treatment, the thermal silicone pad needs to be placed for a period of time, and then cut with different sizes and specifications after natural cooling, instead of other rapid cooling methods. Otherwise, it will directly affect the product performance of thermal conductive silicone pad.
5. Finished product inspection
The main items to be tested include: thermal conductivity, temperature range, volume resistivity, voltage resistance, flame retardant, tensile strength, hardness, thickness, etc.
