PURPOSE: To obtain a favorable flange while preventing spring back of the flange from happening by a method wherein a thermoplastic resin pipe is made of a single layer of multi-layer molded form which has a resin layer of which dielectric loss is not less than a specific value.
CONSTITUTION: For a thermoplastic resin can which is manufactured by processing the opening end part, a thermoplastic resin pipe is a single layer or multi-layer molded form which has a resin layer of which dielectric loss (dielectric constant × dielectric power factor tan δ) is not less than 0.03. When the opening end part of the thermoplastic resin pipe is processed, it is heated by a high frequency, and an electrode which generates high frequency is provided on a protruding part of a flange molding die and at a position which does not protrude to the outside of the protruding part. For resins of which dielectric loss (dielectric constant δ × dielectric power factor tan δ) is not less than 0.03, there are saponified substance of ethylene/vinyl acetate copolymer, polyamide resin or vinyle chloride resin, and it is desirable to be a single layer or multi-layer molded form of these resins. Also, for a period of time for which the high frequency is cast upon to heat the thermoplastic resin can, approximately 2-20sec are appropriate.
FURUSE TATSUO
TERAUCHI YUSUKE
