PREPARATION OF THERMOPLASTIC RESIN FOAMED MOLDING IN MOLD

摘要

PURPOSE:To obtain an excellent foamed molding without any complicated curing process even when prefoamed particles of insufficient foamability are used by pressing and cooling the foamed molding having been heat-foamed by filling thermoplastic resin prefoamed particles in a mold with an inorganic gas. CONSTITUTION:As the base resin or thermoplastic resin prefoamed particles, polyolefine resins can be used. The thermoplastic resin prefoamed particles can be prepared by foaming foamable resin particles containing a foaming agent in a pressure container under pressure. The prefoamed particles are filled into a mold and heated to be foamed and molded. A steam whose gauge pressure is 2-5kg/cm<2> is used for heating the prefoamed particles. The molding obtained by heating and foaming the prefoamed particles in a mold is pressed with an inorganic gas. The gas contained in the molding is prevented from going out while the molding is cooled down and the shrinkage of the molding can be avoided by pressing the gas into the molding. The pressure of the inorganic gas consisting mainly of nitrogen is usually about 0.01-5kg/cm<2>.G.