| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing the subject foam by which the foamability even when carbon dioxide gas is used as a foaming agent, is im proved by using a specific resin as a foaming auxiliary to be formulated with an aromatic vinylic resin. SOLUTION: A resin composition comprising (A) an aromatic vinylic resin and (B) (i) a rosin-based resin and/or (ii) a polyester-based resin as a foaming auxiliary is foamed by using carbon dioxide gas to provide the objective foamed body. The component (i) preferably has 70-180 deg.C softening point, and the component (ii) preferably has 30-160 deg.C softening point or melting point. The amount of the added component B based on 100 pts.wt. component A is 0.1-50 pts.wt. According to the method, lowness of the solubility of the carbon dioxide gas in the component A can be compensated, and the melt-foaming by using a pressure used in the conventional foaming method is enabled, because the resin capable of easily dissolving the carbon dioxide gas is used as the foaming auxiliary.
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