| 摘要 |
PURPOSE:To improve the heat resistance of neck part, the lower side of the neck and bottom part and to minimize the thermal deformation of said parts by a method in which the intermediate layer made of heat resistant resin is molded at the neck part, the lower side of the neck and the bottom part, thereby obtaining multilayer structure. CONSTITUTION:In the preform of the thin wall-vessel made of the thermoplastic resin such as polyethylene terephthalate etc., first, the main body-molding resin of the quantity for molding neck part 2 is injected. Next, the injection of the main body-molding resin is stopped once, and the heat resistant resin such as polyarylate molding the neck part 2 and the intermediate layer 5 below the neck part is injected. Immediately before said injection is finished, the injection of the main body-molding resin is again started and the main body-molding resin of the quantity molding barrel part 3 is injected. During this injection, the injection of the heat resistant resin is stopped. The injection of the main body-molding resin of the quantity molding a bottom 4 following the injection of the quantity of the barrel 3 is carried out at the injection pressure set low. Then, the injection of the heat resistant resin of the quantity molding the intermediate layer 6 of the bottom 4 is started, whereby both resins are injected in the state of coextrusion. |
