MANUFACTURE OF DOUBLE WALL BLOW-MOLDED PART AND PARISON AND DOUBLE WALL BLOW-MOLDED PAT THEREOF

摘要

PURPOSE:To enable to clearly transfer patterns onto the outer surface of a molded part simultaneous with the injection of resin by a method wherein a blown parison is formed on the direct end of the top of the molded part and at the same time in the interior of its side wall so as to form an inner wall surface by stretching to the shoulder part and in the interior of the side wall. CONSTITUTION:A cavity impression 5 for parison is formed by a core 1 and a cavity 3, both of which are inserted respectively from above and below a split mold 1. Further, a cavity impression 6 for molding the outer surface of a molded part is formed at the outside of the cavity impression 5 in such a manner as to communicate with the cavity impression 5 between the split mold 1 and the cavity 3. In addition, patterns 7 are engraved onto the inner surface of the split mold 1, which forms the cavity impression 6. Synthetic resin is injected through a runner 8 into the cavity impressions 5 and 6 under the conditions that the core 2 and the cavity 3 are heated up to a certain temperature and at the same time the split mold 1 is cooled, resulting in letting the resin filled in the cavity impression 6 to form a side wall 10, on which the patterns 7 are perfectly transferred because said resin is cooled and solidified while being in close contact with the patterns 7 engraved onto the wall surface of the split mold 1 and on the other hand, in allowing the resin filled in the cavity impression 5 to keep in heated state and to be formed in a parison 11 kept at a temperature enabling to blow-mold.