Parison for bottle product

摘要

A parison for producing a bottle by the biaxial orientation. The parison is prepared by injection-molding a synthetic resin into a bottomed tubular shape. The parison has its bottom portion made gradually thicker from the center of the outer circumference thereof such that the bottom portion can be uniformly oriented at a similar orientation rate to that of the drum portion of the bottle product. The bottom portion is made to protrude into such a generally semispherical shape that the radius of the outer spherical surface thereof is made larger than that of the inner spherical surface.