Polytetrafluoroethylene elastic band is a good sealing material. It is made of pure polytetrafluoroethylene dispersed resin, which is pressed and stretched at high temperature. It has the advantages of low friction coefficient, chemical corrosion resistance, good sealing, no hydrolysis, and no hardening. It can be used at temperatures ranging from -160 ° C to+280 ° C and is suitable for sealing reaction vessels, steam turbines, and various shaped mouth tanks and barrels.