MANUFACTURE OF THERMALLY FIXED ORIENTED CONTAINER

摘要

PURPOSE:To obtain a biaxially oriented blow molded container of thermoplastic polyester to the whole of which thermal fixation has been applied stably without whitening the bottom and a shoulder part of the container, by a method wherein blow molding and thermal fixation are applied to a preform within a mold whose mold surface corresponding to a shell part and that corresponding to the bottom and shoulder part are heated respectively at a high temperature and low temperature, a molded product is cooled and shrunk by unloading the same, held within a secondary mold and molded under blowing-in of a fluid. CONSTITUTION:An inner cylindrical part 4 of a cavity mold is provided by applying heat insulation to the same and the inside of the same is provided with a heater 8. A mold surface 11 corresponding to a shell part is heated at a high temperature and, on the one hand, mold surfaces 12, 13 corresponding to a shoulder part and the bottom are heated at the temperature which is lower than that of the mold surface 11 corresponding to the shell part and does not become more than the whitening temperature. Biaxially oriented blow molding is applied to a preform in the mold, a formed molded product is held within the mold in a state that fluid pressure is applied to the inside and thermal fixation is applied to the same. The molded product is cooled by unloading the same by breaking the mold and shrinkage is allowed. The cooled and shrunk molded product is held within a secondary mold and molded into the final container form under blowing-in of a fluid.