| 摘要 |
Disclosed is a process of making an oriented and heat set blow molded bottle of poly(ethylene terephthalate) so that the bottles resulting from the process have a density over 1.3860 cc./gm. and an onset-of-shrinkage temperature over 80 DEG C. In the process preform preheated to a temperature suitable for orientation is biaxially stretched in a blow mold and then while the hollow article walls are still in contact with the blow mold walls, the article is raised to a higher heat setting temperature in the range of 200 DEG -250 DEG C. (except for the neck) thus heat setting the bottle, and while the article is still at a shrinkage resisting pressure exceeding atmospheric cooling the article to a temperature at which it maintains its shape when not pressurized but not below 100 DEG C. It is also particularly disclosed that this cooling step can be done outside the mold. In a special embodiment of the invention where the cooling step is effected outside the mold, the cooling under the shrinkage resisting pressure is below 100 DEG C., even down to room temperature and lower, before the shrinkage resisting pressure is released from the hollow article.
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