Patent ID: 7906056

Claim:
A method of forming a closed tube head part having a closing material attached thereto by a compression method, the method comprising the steps of: fitting a cup-shaped closing material having a convex section and a metal foil base material onto a protruding engagement section of a distal end of a mandrel in a manner that a clearance is provided between a rear side of a distal end surface of the convex section of the closing material and the protruding engagement section of the distal end of the mandrel; disposing a molten resin in a cavity of a molding die; pressing a holepin having an outer peripheral section of a distal end that is smaller than the outer periphery of the distal end section of the convex section of the closing material against a central portion of the distal end surface of the convex section of the closing material to pleat the distal end surface of the convex section of the closing material and form an annular corner protrusion at its outer peripheral section; and inserting the mandrel under pressure into the cavity of the molding die while the holepin remains pressed to cause the molten resin to be pushed and charged into the cavity such that the molten resin envelops and flows completely over the annular corner protrusion section to become interlocked therewith, thus forming the closed tube head part with the closing material attached thereto.