Detailed Explanation of PTFE Impregnation Coating Process

The critical factors in the impregnation process include the concentration of the PTFE dispersion, drying, baking, and sintering temperature and speed.

The concentration of PTFE dispersion directly affects film thickness, resin content and flatness.

The higher the concentration, the greater the thickness of the resin after impregnation, but the thickness of each impregnation should not be too large. Generally, during the multiple impregnation process, the dispersion concentration gradually increases. In addition, applying additives such as softeners and surfactants in the dispersion is also critical.

Generally, the resin is dried, baked and sintered in a three-zone vertical oven. The temperature in the range is continuously gradient and divided into three main temperature zones: the drying zone dries the impregnated glass fiber cloth and removes the moisture in the dispersion; generally, if the temperature is too high at 80~100℃, bubbles or flow marks may be generated; in the baking area, the residual moisture and surfactants on the cloth are removed. Generally, the temperature is 260~290℃. The material may become sticky if the temperature is too low. Fabric high temperature in the sintering zone melts the resin, eliminates the interface, and makes it have better adhesion with the glass fiber cloth, thereby plasticizing the film. The temperature is generally 380~400 °C.

The temperature of the impregnation tank is generally room temperature (20~25℃).

The speed directly affects the product's drying and sintering quality and production efficiency. If the rate is too fast, it will affect the amount of impregnated resin and the effect of drying and sintering. If the speed is too slow, it will affect the production efficiency and is not conducive to reducing costs.