I.
It is weaved by PTFE fiber after tension and strengthening as well as PTFE emulation soaking. It is suitable for chemical industry (other than Fluorine gas and alkali metals), pharmacy, food, papermaking, chemical fiber and other industries. It has stable chemical property, well heat resistance, low coefficient of friction, and good wear resistance and so on. But it has some disadvantages as well: it has worse heat conductivity, which will lead to packing leakage because of burning, its thermal expansion coefficient is larger, and therefore, it is easy to creep under certain temperature and pressure, or it may lead to cold-flow and reduce the sealing effect.