| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to cope with an external stimulus of high-pressure steam sterilization or the like and to maintain a proper peeling strength by forming a welding surface in the lower part of a main body and forming projecting parts so that they overlap this welding surface. SOLUTION: A welding mold 1 has a ring-shaped welding surface 3 formed in the lower part of a main body 2 and a plurality of projecting parts 4 formed at prescribed intervals so that they overlap the welding surface 3. The surface of contact of the projecting part 4 with a cap member may be formed in any one of shapes of a circle, a rectangle and dots in a plurality. Moreover, the length of the projecting part 4 is made to be 0.05-0.3 mm according to the thickness of a synthetic resin film constituting the cap member. The cap member constituted of the synthetic resin film is held between a body to be welded (stopper body holder constituting a mouth part) and the welding surface 3 in the lower part of the welding mold 1 and the projecting parts 4 and it is passed through a preheating process (wherein the surfaces of the cap member and the body to be welded are melted) and welded in a heating process (wherein the cap member and the body to be welded are welded by pressing and heating). |
