Patent ID: 6357802
Filing Date: 2002-03-19
Classification: B29C,F16L

Abstract:
A manufacturing method of a pipe made of a rigid thermoplastic resin in which a ring-shaped projection is thermoplastically integrated on an inner surface of a pipe main body, comprising:a pipe main body molding step of molding the pipe main body made of the rigid thermoplastic resin by injecting a molten material of a polyamide resin, a polybutylene terephthalate resin, or a polyphenylene oxide resin into a pipe-shaped cavity formed by splittable molds, and a ring-shaped projection molding step of injecting a molten material of a butadiene-acrylonitrile rubber or an ethylene-propylene rubber into a ring-shaped cavity formed along the inner surface of the pipe main body by the molds themselves or combining another mold, and thermoplastically integrating the ring-shaped projection made of an elastic resin and having a sealing property on the inner surface of the pipe main body while performing vulcanization, and wherein the ring-shaped projection is thermoplastically integrated on the inner surface of the pipe main body by mounting in the mold a slide pin that pierces a pipe-shaped cavity formed by the mold and injecting the molten material of the polyamide resin, the polybutylene terephthalate resin, or the polyphenylene oxide resin into the cavity to mold the pipe main body in the pipe main body molding step; and then injecting the molten material of the butadiene-acrylonitrile rubber or the ethylene-propylene rubber into the ring-shaped cavity via a slide-pin's drawing hole of the previously molded pipe main body in the ring-shaped projection molding step.