| 摘要 |
PURPOSE:To improve gas barrier properties and impact-resistant and ply-separating properties, by a method wherein stretch blow molding of a preform in a multilayer structure is performed within a blow mold and a gas barrier thermoplastic resin layer is formed on an inner surface side rather than the center position between an inside and outside layers of thermoplastic polyester resin. CONSTITUTION:Polyethylene terephthalate is fed to a central flow path 2 and outer and annular flow path 3 and polymetaxylene adipamide is fed to an inner and annular flow path 4 as gas barrier resin. A part of molten PET is injected into a cavity through a hot runner nozzle 5 from the central flow path 2 in the early stage of injection. Successively, the molten PET and PAM are injected at a time respectively through the central flow path and outer and annular flow path and the inner and annular flow path. The molten PET is injected through the outer and annular flow path in the early state of the injection and a multilayer preform of two kinds, three layers and 5mm in thickness obtained by providing an intermediate layer in the center is molded. The multilayer preform is heated at about 100 deg.C, biaxially stretched blow molding of which is performed and a vessel whose inner capacity is 1,000ml is obtained. A position and thickness ratio of the intermediate layer is almost uniform and the position of the intermediate layer exists uniformly at such a position of 37-39% of a thickness. |
