| 摘要 |
PURPOSE:To efficiently manufacture a foam with large sectional area by a method wherein a ring-shaped plate, the sectional shape of which gradually increases toward the extrusion direction, is provided in a tubular molding tool to extrude and mold a polyetherimide foam. CONSTITUTION:A tubular molding tool 2 containing an annular molding plate 3 is mounted to the tip of an extrusion orifice 1. Acetone-impregnated polyetherimide is extruded under the state of being melted by heating (195-200 deg.C) from the extrusion orifice 1 into the molding tool 2 so as to extrusion-foam the polyetherimide in order to obtain a foam, the surface of which is smooth and the percentage of closed cells of which is good. In addition, used polyetherimide compositions are the proper combination of compounds among compound groups A, B and C as described later. Thus, an extrusion-foam with large sectional area, which is useful as the core material of lightweight composite panel of aircraft or the like, is obtained. |
