The basic process of processing PTFE resin is to first form a compact powder by compression, fuse the adjacent surfaces of the powder particles into one by heat sintering, and then cool and shape.

    The above three stages will affect the three main factors that determine the performance of the product:

    1. The void content in the PTFE product;

    2. Product cleanliness;

    3. The molecular weight of the product.

    When PTFE is heated to 327 ° C, an important change occurs, that is, from a crystalline material to an amorphous body, and when the sintering temperature (360 ° C ~ 400 ° C) is cooled, the opposite process occurs. That is, the amorphous form changes to a crystalline state. The crystallinity of the product being cooled. This is related to the rate of cooling and its molecular chain length.

    Slowly cooled articles have higher crystallinity and density than fast cooled articles. PTFE molecules with relatively low molecular weight have higher crystallinity and density than molecules with higher molecular weight.

    The voids in the Teflon molded and extruded articles must be managed to a minimum, otherwise the voids present not only affect the mechanical properties and chemical resistance of the article, but also significantly reduce its use as a strong electrical insulating material. It can be seen that the density of the PTFE product becomes an important parameter for identifying the void content and product quality of the product, and the smaller the density, the larger the amount of voids contained in the product.

    Whether suspended or dispersed in Teflon products, their relative density is generally between 2.12 and 2.23. The specific values are related to the processing, especially the cooling rate.