| 摘要 |
PURPOSE:To prevent waviness of a molded skin and scatter of thickness, by covering the core material surface with a heat insulating soft urethane foam having a softening temperature higher than the molding temperature of a thermoplastic resin. CONSTITUTION:A prepared core material 1 is fixed by inserting the end of a stay section 4 thereof into a hole 13 of a core material supporting table 12 of wood and the center of the core material 1 is positioned at the lower parts of blow molds 11, 11' so that the core material 1 may be surrounded by a parison 10. Then a vinyl chloride composition that has been heated to 200 deg.C to be plasticized is extruded from a die 8 of an extruder into as a parison 10 having a size a little larger than the outer size of the core material 1. At a curved section (a) of the core material 1 where it is covered with an urethane foam, the parison is lowered with it in contact with the urethane foam. When the parison reaches a point lower the blow molds, the molds are closed, and then immediately air is blown from a compressed air blowing nozzle 9 to expand the parison into the shape in conformity with the molds.
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