Poly tetra fluoroethylene (abbreviated as PTFE), commonly known as "plastic king", is a polymer prepared by polymerization of tetrafluoroethylene as monomer, chemical formula is (C2F4)n, excellent heat resistance, cold resistance, can be used for a long time at -180~260oC. This material has the characteristics of acid and alkali resistance, resistance to various organic solvents, and is almost insoluble in all solvents. At the same time, PTFE has the characteristics of high temperature resistance, and its friction coefficient is extremely low, so it can be used as lubrication, and it has also become an ideal coating for the inner layer of easy-to-clean water pipes.