| 摘要 |
<p>PURPOSE:To improve heat resistance, shock resistance and transparency by eliminating leak of liquid, by a method wherein the thickness at the neck part of a bottle body is made thick and moreover a preform is heat-treated for a fixed period of time prior to biaxial orientation blow molding. CONSTITUTION:Inner circumferential diameter (a) at the neck part of a bottle is 60-80% of the outer circumferential diameter (b) and the overall light transmission rate at the neck part is made at least 60%. Then a preform to be used for biaxial orientation blow molding is obtained by injection molding. Then, the whole of the preform or a part of the preform corresponding to the neck part of the bottle body 3 is biaxial-orientation-blow-molded beforehand in an oven. The title method performs biaxial orientation blow molding after stress is mitigated by heat-treating beforehand for 1-60 minutes at a temperature of 60-140 deg.C so that transparency of the bottle body 3 is not lost.</p> |
