| 摘要 |
PURPOSE:To effectively prevent the irregular deformation from occurring in an intermediate formed item and consequently obtain a stably heat-set biaxially stretched thermoplastic polyester blow-formed vessel by a method wherein the intermediate formed item is stretch-blow- formed in such a manner that the ratio of the diameter at the belly of the intermediate formed item to that at the belly of a final vessel shape is made larger than the ratio of the diameter at the bottom of the intermediate formed item at the state before cooling to that at the bottom of the final vessel shape. CONSTITUTION:A bottomed preform, which is made of thermoplastic polyester and has a neck part corresponding to the neck part of a vessel, is employed so as to be biaxilly stretch- blow-formed in a primary mold in order to heat-set the resultant formed item held in the mold. The intermediate formed item is taken out of the primary mold and cooled under the state that the shrinkage of the intermediate formed item is permitted. After that, under the condition being held in a secondary mold, the intermediate formed item is finally blow- formed so as to form a final vessel shape consisting of the neck part, a shoulder and a bottom. When the diameter (d) at the bottom 1a of the intermediate formed item at the stage before cooling is (n) times larger than the diameter d' at the bottom 1b of the final vessel shape, the stretch-blow-forming is performed in the primary mold in such a manner that the ratio (m) of the diameter D of the belly 2a of the intermediate formed item to the diameter D' of the belly 2b of the final vessel shape is made larger than the ratio (n). |
