MANUFACTURE OF PREMOLDED BODY

摘要

PURPOSE:To provide a manufacture of a premolded body which can impart favorable heat resistance to a mouth part and also dimensional properties of the mouth part is not deteriorated. CONSTITUTION:Injection molding is performed by holding only a mouth part mold 11 at the crystallizing temperature or higher of injection molding resin and the other partial molds 12, 13 at the temperature lower than the glass transition temperature of the resin by making use of an injection molding tool 1 constituted of a plurality of the partial molds including the mouth part mold 11 coming into contact with an outside part of a mouth part and having a cavity 20 in a form corresponding to a premolded body. After the injection molding, the obtained outside part of the mouth part of the premolded body is cooled gradually within the mold and a part other than the outside of the mouth part is cooled down suddenly to the glass transition temperature or lower. This is a method wherein the other partial mold of the injection molding tool is released as the mouth part of the premolded body 2 is held by the mouth part mold 11 whose temperature is held at the crystallizing temperature or higher and a part other than the mouth part of the premolded body 2 is cooled by a cooling mold 14.