FOAMING AGENT MASTERBATCH COMPOSITION FOR INJECTION MOLDING AND ITS PRODUCTION

摘要

PURPOSE:To obtain the title composition which can realize low-temperature molding when injection molding is performed by using it to thereby make it possible to shorten the time required for cooling the molding in a metal mold, by formulating a masterbatch composition comprising a dispersion of a specified foaming agent and a decomposition aid in a base resin so that the gas due to the decomposition of the foaming agent is generated in a specified manner. CONSTITUTION:A masterbatch composition made by dispersing a foaming agent comprising azodicarbonamide and a decomposition aid (e.g. ZnO and zinc stearate) in a base resin (e.g. low-density polyethylene), wherein the amount of gas generated due to the decomposition of azodicarbonamide becomes constant within 8min at 170 deg.C. This composition is obtained preferably by mixing 100 pts.wt. base resin with 20-50 pts.wt. azodicarbonamide and 7-20 pts.wt. decomposition aid at a temperature above the softening temperature of the base resin and not exceeding 120 deg.C and molding the mixture.