PTFE Expanded Joint Sealant Colour: White Shape: Sheet, Strip PTFE Expanded Joint Sealant (Superseal) is a 100% PTFE-based tape sealant, suitable for use in a wide range of sealing applications. Some examples include applications dealing with large equipment flanges, complex surfaces and rough or pitted flanges. PTFE itself, in nature, is a material with excellent chemical-resistance and good high temperature performance.