Method of producing extruded plate-like polystyrene foam

摘要

In a method of producing a plate-like polystyrene resin foam which comprises extruding a molten mixture of a polystyrene resin and a volatile blowing agent from an extruder into a zone kept at a lower pressure than the inside of the extruder, the improvement wherein the volatile blowing agent is a mixture consisting of 50 to 80% by weight of dichlorodifluoromethane and 50 to 20% by weight of ethyl chloride and is present in said molten mixture in a proportion of 8 to 17 parts by weight per 100 parts by weight of the polystyrene resin.