| 摘要 |
PURPOSE:To stably obtain the subject expanded material having uniform and fine foams by extruding a specified resin composition into the inside of a die having a molding zone, etc., continuously formed in a closed state from the inlet of an extruder, heightening the inner pressure of the above-mentioned die and extruding a partially expanded material. CONSTITUTION:A resin composition composed of a thermoplastic resin, an expanding agent and a crosslinking agent is extruded from an extruder 1 through the outlet 1a of the extruder into the inside of a die 2 (shaping zone 2a, heating zone 2b and cooling zone 2c are continuously formed) and a part of the crosslinking agent and the expanding agent are decomposed at the above-mentioned shaping zone 2a and/or the heating zone 2b so as to form a partially expanded molding 5. The resultant partially expanded molding 5 is cooled to <softening temperature thereof at the cooling zone 2c and a damping force is applied to the cooled molding 5 so as to heighten the inner pressure of the above-mentioned die 2. The above-mentioned molding 5 is extruded from the die 2 thereby and then heated under the ordinary pressure at the heating furnace 3 for expansion, thus obtaining the objective crosslinked and expanded material 6. In addition, a closed system is adopted from the inlet of the extruder 1 to the outlet of the die 2. |
