| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a foamed sheet of a polystyrene resin for heat molding, by which the sheet with such advantages that a rolled foamed sheet can be aged for an aging period of about two weeks even during winter time, and the heat moldability of the rolled foamed sheet is stabilized in the rolling direction and the width direction and further, a molded product with a specified forming thickness can be obtained, with a long sheet life, and a foamed sheet of a polystyrene resin. SOLUTION: In the method for manufacturing the foamed sheet of a polystyrene resin for heat molding, by which a polystyrene resin and a physical foaming agent are thermally kneaded into a foamable molten resin by an extruder and the foamed sheet is obtained by extruding/foaming the molten foamable resin, the physical foaming agent is composed mainly of a mixed physical foaming agent (the total amount of the foaming agent is 100 mol%) comprising a total of 50 to 95 mol% of at least one foaming agent selected from isobutane, normal pentane and isopentane; and 5 to 50 mol% of at least one foaming agent selected from a carbon dioxide gas, water, an ether with a boiling point of 140°C or lower and a dialkylcarbonate with a boiling point of 140°C or lower. COPYRIGHT: (C)2003,JPO |
