METHOD OF MANUFACTURING POLYLACTIC ACID RESIN FOAMED SHEET FOR THERMOFORMING AND METHOD OF MANUFACTURING SHEET MOLDING

摘要

PROBLEM TO BE SOLVED: To provide a method of manufacturing a sheet molding, capable of manufacturing the sheet molding reduced in a remaining amount of a foaming agent, by facilitating adjustment of an open cell ratio of a polylactic acid resin foamed sheet for thermoforming.SOLUTION: There is provided a method of manufacturing a polylactic acid resin foamed sheet for thermoforming, in which the polylactic acid resin foamed sheet for thermoforming is manufactured by carrying out a sheeting process of manufacturing a polylactic acid resin foamed sheet by extruding and foaming a polylactic acid resin together with a foaming agent. The method of manufacturing the polylactic acid resin foamed sheet for thermoforming includes further carrying out a heat treatment process of improving the open cell ratio of the polylactic acid resin foamed sheet by heating the polylactic acid resin foamed sheet obtained in the sheeting process to the crystallization start temperature of the polylactic acid resin or higher.