| 摘要 |
PURPOSE:To permit a foamed cell to be molded in keeping the surface condition thereof well without generating coarse foaming by a method wherein an inner air ring for blasting air against the inner surface of the tubular product of plastics, which is molded by a die, is provided immediately near the die. CONSTITUTION:A hollow core shaft 14, supporting the main body 13 of a plug, is inserted into and fixed to the axial center of the main body 13 of the plug while another hollow shaft 20 is inserted slidably into the hollow core shaft 14. The tip end of the hollow shaft 20, which is projected from the main body 13 of the plug, is provided with an inner air ring 22, equipped with annular nozzle 21 for ejecting air annularly. The inner surface of the tubular product P of plastics is cooled by cooling air ejected from the nozzle 21 of the inner air ring 22 immediately after being extruded out of a die 9. |
