GASKET FOR SANITARY PIPING AND ITS MANUFACTURE

摘要

PURPOSE: To certainly prevent penetration leakage which is a fatal defect for its material without eliminating a characteristic and significance of porous polytetrafluoroethylene used as its constitutional material on a gasket for a sanitary piping made of porous polytetrafluoroethylene. CONSTITUTION: A surface layer of a gasket inner peripheral part 1c directly making contact with enclosed fluid is made to a non-porous melt hardened layer 1'c by melting and hardening it. The melt and hardened layer 1'c becomes thick at its central part in the thickness direction of the gasket 1 and thin at both end parts of it.