| 摘要 |
PROBLEM TO BE SOLVED: To obtain a foam excellent in heat insulating properties, lightweight properties and economy by mixing expandable polystyrenic resin particles comprising a polystyrenic resin having a specific mol.wt. and, incorporated therein, a blowing agent and a plasticizer each in a specific amount with an expandable polyurethane and allowing concurrent expansion of the expandable polystyrenic resin particles with expansion of the urethane. SOLUTION: This composite foam is obtained by mixing expandabable polystyrenic resin particles comprising a polystyrenic resin having a weight- average mol.wt. of at least 200,000 and not more than 350,000 and, incorporated therein, 2-10 wt.% of a blowing agent and 1.5-10 wt.% of a plasticizer with an expandable polyurethane and allowing concurrent expansion of the expandable polystyrenic resin particles with expansion of the urethane. Preferably, the plasticizer contained in the expandable polystyrenic resin particles comprises 0.1-5 wt.% of a high boiling-point plasticizer, which is liquid at ordinary temperatures and has a boiling point of at least 150 deg.C, and 0.5-9.9 wt.% of an aromatic hydrocarbon and the total content of these two is 1.5-10.0 wt.%.
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