| 摘要 |
<p>PURPOSE:To provide an injection mold where a preform having an undercut in a mouth part can be molded and smooth mold release can be realized and a form of a mouth part of a resinous vessel where mold release after injection molding can be realized more smoothly. CONSTITUTION:In a mouth part 22 of a preform having an undercut 18, its inner wall is regulated by the second injection core mold 40 and in its outer wall, a nonundercut area is regulated by the first lip cavity mold 60 and an undercut area is regulated by the second lip cavity mold 70. In mold release after injection molding, the second lip cavity mold 70 is moved upward and a space where no interference member is in existence is secured on the outer circumference of the undercuit 18. After the space is securred, the second injection core mold 40 is raised and moved and the mold release by forced pulling-off of the second injection core mold 40 is realized while the undercuit 18 is being deformed outward elastically by making use of the above-mentioned space.</p> |
