Injection-blow molding

摘要

A molecularly oriented plastics bottle is made by blow molding an injection molded parison (20) having a flat a bottom wall (24) which is thinner than the parison sidewall. Mold and core rod combination for forming a plastic parison for stretch/blowing into a plastic bottle comprising a core rod (30) with an end mated to the mold (10) so as to permit formation of a parison with a flat bottom and wherein the bottom corners of the parison have a sharp taper. The core rod is preferably shaped to include a shoulder having a substantially straight outer wall at the mouth end of the parison mold, and constructed and arranged with the mold to permit deposit of additional plastic at the inner wall of the shoulder of the parison (26). Parisons formed with the disclosed mold-core rod combination permit a deeper and longer stretch of the parison without tearing or deformation of the parison bottom or deformation or wrinkling at the shoulder of the finished bottle while providing essential wall strength.