Revolution and advance and retreat interposing the screw

摘要

PROBLEM TO BE SOLVED: To provide a feeder of a molding material that reduces, as much as possible, the yellowing occurring when melting a molding resin.;SOLUTION: The injection molding method or the injection molding apparatus comprises: a nitrogen gas supply means consisting of a pipe line P1 of the nitrogen gas that leads nitrogen gas to the upper part of a molding material supply port 20 locating under a hopper 24 and formed in a barrel 10 through a hopper stand 14 and furthermore discharges the nitrogen gas toward the periphery of a screw shaft 12 in a predetermined depth in the molding material supply port; an exhaust passage formed so as to lead the discharged nitrogen gas and remaining air through the gap between the barrel inner surface and the screw shaft periphery and furthermore through the inside of a barrel support 16 and a barrel holder 18 to external connected outlets 16B and 18B prepared at the barrel support and the barrel holder; and a vacuum generator which sucks the nitrogen gas or the like from the exhaust passage, wherein the interfusion of air from the molding material supply port to a plasticization zone is prevented and the generation of the yellowing resulting from the oxidation of a molten resin is inhibited.;COPYRIGHT: (C)2007,JPO&INPIT