PTFE stands for “Polytetrafluoroethene.” It is a type of “Engineering plastic,” a plastic from ethylene resin combining chlorine atoms and carbon atoms, and discovered by Dupont company in 1938 by accident. The patent was obtained in 1941 in the name of “Teflon” as a trademark. In addition to the Chemours company (original DuPont company) that produces PTFE raw materials, the other well-known brands include 3M (Dyneon), Daikin, and ASAHI (AGC).