| 摘要 |
PURPOSE:To make it possible to blow-mold a container on the inside face of which projections are requested, by a method wherein a mandrel, split molds, which are provided at the position surrounding the tip part of a compression member and a means to blow pressure fluid into a parison are contained and, in addition, recessed strip parts are provided in the outer peripheral surface of the mandrel. CONSTITUTION:Molten resin is extruded from an extrusion port 7 with the lower end part of a mandrel 6 positioned higher than the extrusion port 7. As result, extruded parison 11 is extruded towards the center of the mandrel so as to gather in order to close the lower end part of an extrusion head 1. Next, a compression member 8 is lifted so as to compress the closed portion of the parison 11 by pinching it between the upper end of the compression member 8 and the lower end of the mandrel 6. Next, by integrally lowering the mandrel 6 and the compression member 8 and extruding molten resin from the extrusion port 7 the state that the supply of the molten resin to the extrusion head is controlled, the parison formed along the outer periphery of the mandrel 6 enters respective recessed strips 6a, 6b, 6c,.... When both the mandrel 6 and the compression member 8 lower to the predetermined position, split molds 9 and 10 are closed in order to blow-mold by blowing pressure fluid in the parison 11. |
