| 摘要 |
PROBLEM TO BE SOLVED: To obtain a foamed body that includes substance having a specific bulk density, high flexibility, and sufficient elastic recovery by heating the material at a temperature higher than Tg of the material but lower than its melting point under vacuum and specific conditions. SOLUTION: A polyester material is heated at a temperature higher than Tg of the material, but lower than the melting point of the material for a time sufficient to attain at least 30% reduction in its bulk density whereby an aromatic polyester foamed material having preferably 50-700 kg/m<3> bulk density, and preferably <=15%, or >=30% crystallinity is obtained. |
