METHOD AND APPARATUS FOR PREVENTION OF BLACK POINT AND FOREIGN MATERIAL FROM OCCURRING IN PLASTIC RESIN PLASTICIZED PART

摘要

PURPOSE: To provide a method for and an apparatus of prevention of a black point and foreign material from occurring in a plastic resin plasticizing apparatus wherein the degree of freedom of operating time of the plasticizing apparatus can be increased while inferiority in molding is prevented from occurring by preventing inferiority by oxidation of resin remaining in the plasticizing apparatus in reworking. CONSTITUTION: A nitrogen gas generator 11 which feeds nitrogen gas to a plastic resin plasticizing part (a lower part of a hopper 4), and a nitrogen gas feed timing setter 18 which sets time for feeding nitrogen gas are provided in a plastic plasticizing apparatus. Timing when the resin is most oxidizable is taken as time for feeding nitrogen gas to the plastic resin plasticizing part with the nitrogen gas feed timing setter 18. The timing is before raising the temperature prior to operation with the plastic plasticizing apparatus, in stopped plasticizing operation during operation, and in cooling after ending the operation.