| 摘要 |
PURPOSE:To obtain an expanded material having a uniform skin layer when heated and melted cylindrical thermoplastic resin is put into a molding box, and compressed air is pressed in to perform blow molding by expanding expandable particles by the use of molding heat. CONSTITUTION:A polyethylene parison 2 that is adjusted to form a skin is dropped from a mold 1. Mold members 3, 3' are closed and compressed air with a fixed amount of beads is blown in from an inlet port 4. The parison is expanded and the beads are expanded by the temperature of the parison. Then, a blowpipe 5 is removed, air is taken out and the parison is cooled for about 20sec. In the meanwhile the beads are expanded, melted inside the skin layer and welded to one another and the inner part of the skin is filled with the beads. When the mold is removed, expanded materials having a skin layer can be obtained. |
