METHOD AND APPARATUS FOR BLOW MOLDING

摘要

PURPOSE:To prevent the generation of a die line even when a parison is continuously extruded for a long time by holding at least the outside in the vicinity of an extrusion orifice of the parison extruded from the leading end of the die core of a blow molding apparatus to an inert gas atmosphere. CONSTITUTION:The inner periphery of the upper part 4a of a ring-shaped gas injector 4 is mounted to the outer periphery of the lower part of a die 1 and the lower part 4b of the gas injector 4 is opened on the side of an extrusion orifice 3a in circular arc relation to the upper part thereof. A slit-shaped gas jet orifice 4c spraying inert gas to the vicinity outside the parison 5 orifice 3a is formed to the inside upper edge of the opened lower part 4b. A gas introducing pipe 4d receiving introduced inert gas to inject the same from the jet orifice 4c and a gas lead-out pipe 4f leading out the injected gas to the outside from the hermetically closed chamber consisting of the injector 4 and the die 1 through a drilled hole 4e are mounted to the outer peripheral part of the gas injector 4d.