WELDING METHOD OF MODIFIED POLYTETRAFLUOROETHYLENE MOLDED OBJECT, MODIFIED POLYTETRAFLUOROETHYLENE MOLDED OBJECT AND GASKET USING IT

PROBLEM TO BE SOLVED: To provide a welding method of a modified polytetrafluoroethylene molded object capable of smoothly forming a joining part, the modified polytetrafluoroethylene molded object and a gasket using it. SOLUTION: The joining surfaces 12 formed to sheetlike modified PTFE molded objects 10 are arranged in mutually facing relationship and brought into contact with each other to form a sheetlike joined body 14. In this case, the joining line 16 formed to the surface of the joined body 14 and the vicinity thereof are covered with a heat-resistant release film 18 and the joined body 14 is heated while pressed from both surface and back sides thereof by hot molds 20 and 22 through the heat-resistant release film 18. The shapes of the hot molds 20 and 22 are set so that one hot mold 20 is formed so that the length in the direction crossing the joining line 16 at a right angle is made larger (wider) than that of the other hot mold 22. A metallic plate member 24 is interposed between the narrow hot mold 22 and the sheetlike joined body 14. After the completion of heat treatment, the joined body 14 is cooled to room temperature while pressed. COPYRIGHT: (C)2008,JPO&INPIT