ORIENTATION BLOW MOLDING METHOD AND BLOW MOLD ASSEMBLY

摘要

PROBLEM TO BE SOLVED: To easily perform orientation blow molding even a preform of a polyethylene or a polypropylene which is easily breakable during orientation/expanding and a thus far touchy preform of a polyethylene terephthalate which is thick-walled, short and hot, at an extremely low orientation rate and under low expansion pressure compared with a conventional method. SOLUTION: This orientation blow molding system comprises the following steps: loading injection-molded preform inside the cavity of a blowing mold while holding it with a neck insert; the preform set in the cavity is oriented/blow-molded into a packaging container such as a bottle by means of an orientation rod and a blowing air; carrying out the orientation process in the axial direction by the orientation rod upto the bottom surface of the cavity at a low rate of 80mm/s or below; performing the expansion by the blowing air under a low pressure of 0.2 MPa or below; and finally, pressing the wall surface of the molded packaging container to the cavity surface by switching the blowing air pressure to high and thus trimming the container to a neat profile. COPYRIGHT: (C)2004,JPO&NCIPI