LARGE RETURNABLE CONTAINER, MOLDING METHOD AND DEVICE FOR SAME CONTAINER AND BLOW MOLD WITH SEPARATE HEATING ZONES

摘要

A method of molding a large returnable container (40) includes a heat treatment step that includes subjecting a thick preform (10) formed of a polyester resin, or a primary blow-molded article (20) obtained by subjecting the preform to primary blow molding, to intermediate blow molding with heating to obtain an intermediate molded article (30) from which a strain that has occurred during blow molding has been removed, and a final blow molding step that includes subjecting the intermediate molded article that has shrunk to final blow molding with heating to obtain a large returnable container. The heat treatment step includes disposing the preform or the primary blow-molded article in a heat treatment mold (204), and pressurizing the preform or the primary blow-molded article by introducing high-pressure air into the preform or the primary blow-molded article so that a shoulder (22) and a body (24) obtained by blow molding close contact to a cavity surface (204A) of the heat treatment mold, and are subjected to a heat treatment, the shoulder (22) being heated at a low temperature as compared with the body (24).