APPARATUS FOR EXTRUSION MOLDING OF MULTI-LAYERED PARISON

摘要

PURPOSE:To prevent a submaterial resin from mixing in flashes adhering on the outer circumference of a molded article after molding, by controlling the extrusion behavior of the submaterial resin layer of a multi-layered parison. CONSTITUTION:A main material resin R1 extruded in a resin path 12 is divided once into an inner layer and an outer layer by means of a ring member 17 and joined again to prepare a single-layered parison. An adhesive R3 is extruded from nozzles 25 and 25 and a submaterial resin R2 is extruded from a nozzle 24 respectively into a joint of the resin R1. A multi-layered parison containing the submaterial resin layer R2 through the adhesive layer R3 and R3 between an inner main material resin layer R'1-A and an outer main material layer R1-B is extruded. Then, the extrusion of the resin R2 is stopped and the extruding pressure of the adhesive R3 is raised. The movement of the adhesive layers R3 and R3 toward outside are thereby restricted and the adhesive layers move to the resin layer R2 side and cut out the resin layer R2. Then, the extrusion of the adhesive layer R3 is stopped and the extruding pressure of the resin R1 is elevated to cut out both adhesive layers R3 and R3.