| 摘要 |
PURPOSE:To highly efficiently manufacture a bottle, the heat shrinkage of which is small and the shape of which is precise, by a method wherein a parison made of polyethylene terephthalate resin is stretched at high temperature and high speed in a mold kept at a proper temperature. CONSTITUTION:In a method to manufacture a biaxially stretched bottle by blow-stretch forming a parison made of ethylene terephthalate-based polyester, when blow-stretching is performed at the parison temperature of 110-125 deg.C, which is higher than usual, a bottle with a shape faithful to the shape of a mold can be removed from the mold even under the state that the temperature of the mold is raised up to about 110 deg.C and consequently the heat shrinkage of the resultant bottle becomes small. However, on the contrary, the strength of the resultant bottle is slightly lowered. Said lowering of the strength of the bottle is prevented by enhacing the orientation effect through the stretching at the speed as high as 25,000%/min or more. |
