| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for preparing efficiently a sheet-like thermoplastic resin foam while stability of foaming is ensured by preventing preceding foaming at the end part of a foamable sheet from occurring and performing foaming with a similar figure as much as possible. SOLUTION: This thermoplastic resin foam is prepd. by a preheating process wherein a foamable sheet contg. a thermally decomposable foaming agent is preheated at a temp. being higher than the decomposition starting temp. of the above described thermally decomposable foaming agent under pressure, a depressurizing process wherein after preheating, a preliminary foamed sheet is obtd. by releasing pressurizing and a foaming process wherein after depressurizing process is performed, the preliminary foamed sheet is heated at a temp. higher than a completely decomposing temp. for the foaming agent to completely foam the thermally decomposable foaming agent. |
