| 摘要 |
PROBLEM TO BE SOLVED: To provide a preform which can be subjected to biaxial stretch blow molding when a heat-resistant PET bottle having a large volume is obtained by single blow molding using a cold parison method. SOLUTION: The preform comprises a bottomed cylindrical object equipped with a mouth plug and a cylindrical body provided under the mouth plug through a shoulder, submitted when a biaxially stretched blow molded container having a large volume using a polyethylene terephthalate resin is molded by single blow molding using the cold parison method. The neck length under the mouth plug is set so that a longitudinal stretching draw ratio becomes 1.85 or more, and the outer diameter of the body is set so that a lateral stretching draw ratio becomes 3.5 or more. In the case of the preform for the heat-resistant PET bottle having a volume of 2 litre, a basis weight is set to 7.5-70.5 g in addition to the set draw ratios and the wall thickness of the body is set to 40 mm or more. If necessary, a thick-walled part is provided to the inside of the mouth plug and the length of a straight part is set to a predetermined range. |
