| 摘要 |
PROBLEM TO BE SOLVED: To provide a blow molding method in which, when blow molding a hollow-molded article having a thick thickness, the occurrence of blisters like air bubbles can be suppressed, and the hollow-molded articles of high quality can be produced.SOLUTION: Provided is a blow molding method in which the spacing of the die slit in a die head is set corresponding to the aimed thickness of the hollow-molded article to be molded, the molten resin within an accumulator is extruded from the die slit in a cylindrical shape to form a parison, and the parison is molded in the mold; at the start of the extrusion the spacing of the die slit is set to a value smaller than the value set corresponding to the aimed thickness, and then the spacing of the die slit is widened so as to match the value set corresponding to the aimed thickness; in consideration of the thickness reduction caused by the drawdown, it is preferable to compensate the value set corresponding to the aimed thickness; and it is preferable to apply to the case when the thickness of the hollow-molded article to be molded is not smaller than 3.5 mm.SELECTED DRAWING: Figure 3 |
