METHOD OF STRENGTHENING NECK PORTION OF BOTTLE-SHAPED CONTAINER OF POLYETHYLENE TEREPHTHALATE RESIN

摘要

A method of strengthening the neck portion (2) of a bottle-shaped container (1) of polyethylene terephthalate resin which has the steps of heating the neck portion (2) at approx. 140 to 170 DEG C, then inserting a cylindrical die pin (6) having an outer diameter slightly smaller than the bore of the neck portion and cooling function, and blowing chilled air (C) to the neck portion (2), thereby gradually cooling the neck portion (2) to whiten the neck portion. Thus, the neck portion of the bottle-shaped container (1) is strengthened. However, it can effectively prevent the production of incorrect contraction deformation of the neck portion (2) due to the thermal influence of the heat applied from the exterior.