| 摘要 |
PURPOSE:To obtain the subject foam, having a uniform cell diameter and a smooth surface and useful as an electrical insulating material by permeating an aromatic polyether sulfone molded body with gaseous carbon dioxide under pressure, then releasing the pressure, expanding the resultant molded body at a specific temperature and subsequently cooling the expanded molded body. CONSTITUTION:This method for producing a polyether sulfone resin foam is to permeate a resin molded body molded from an aromatic polyether sulfone such as an aromatic polyether sulfone having a recurring unit expressed by the formula with gaseous carbon dioxide under pressure, then thermally expand the resultant resin sheet permeated with the gaseous carbon dioxide at a temperature above the expansion starting temperature and below the Tg of the resin under atmospheric pressure and subsequently cool the expanded resin sheet. The expansion starting temperature of the polysulfone (Tg is about 190 deg.C) having the recurring unit expressed by the formula is 100 deg.C. Thereby, the resin foam, having fine cells and excellent in surface properties and electrical characteristics is obtained. |
