MANUFACTURE OF MOLDED ITEM OF FOAMABLE THERMOPLASTIC SYNTHETIC RESIN

摘要

PURPOSE:To obtain directly a foamed resin molded item without using beads, by feeding a melt of a foamable resin on a mold, foaming it, then putting another mold on it so that the two molds are matched and the foamed resin melt are spread throughout the cavity, and cooling the molds. CONSTITUTION:A molding resin is fed from a hopper 12 to an extruder 1 while a solvent type foaming agent is injected from an inlet 13, and they are mixed under heating and pressure, and the mixture is extruded from a die 11 into a thick thread and is supplied on all of a molding surface 41 of the mold 4. The mixture starts immediately the foaming on the molding surface 41, and when the maximum foaming rate of 50% or more, preferably 60-80%, is attained, the mold 4 and the mold 5 are matched, and after the cavity between the molds 4, 5 is filled with the foamed resin, the molds 4, 5 are cooled and the molded item is removed.