PTFE envelope gasket is a type of static seal, which is composed of elastic materials such as compressed non-asbestos sheet, rubber, ceramics, etc., and a PTFE envelope cove. PTFE has superior properties against chemical and a wide working temperature range. The coefficient of static and dynamic friction of PTFE is very low. So it is the best of the “non-stick” materials with excellent weathering and aging characteristics. Application: It is used to seal pipe flanges glass lined, PVC or FRP. Low bolt torque effecting a seal and chemical compatibility is a main characteristic of this type of gasket.