METHOD FOR MOLDING BLOW BOTTLE CONTAINER MADE OF TRANSPARENT HIGH DENSITY POLYETHYLENE

摘要

PURPOSE:To increase the stress generated in a parison at the time of blow molding by enhancing the melt tension of the parison by irradiating the parison composed of high density polyethylene having specific density with electron beam and subsequently heating the parison to subject the same to blow molding or stretching blow molding. CONSTITUTION:Air is blown in a parison to expand the parison and a bottle container is molded by extrusion blow molding, injection blow molding or stretching blow molding. The parison composed of high density polyethylene having density of 0.935g/cm<3> or more is irradiated with electron beam and subsequently heated to 120-200 deg.C pref. and subjected to blow molding or stretching blow molding. Herein, the quantity of the irradiation with electron beam is set to a range of 20 kilorad-10 megarad and a blow-up ratio is set to 1.5-10. Further, the stretching magnification of longitudinal stretching performed in the first stage in the stretching blow molding after the heating of the parison is set to 1-3 times.