| 摘要 |
Disclosed is a process of making an oriented and heat set thermoformed hollow article of poly(ethylene terephthalate) so that the sidewalls of the articles resulting from the process have a density over 1.391 cc./gm. and an onset-of-shrinkage temperature over 105 DEG C. In the process, a sheet preheated to a temperature suitable for orientation is biaxially stretch thermoformed and then while the hollow article walls are still in contact with the mold walls, the article is raised to a higher heat setting temperature in the range of about 220-250 DEG C. thus heat setting the article, and while the article is still under restraint resisting shrinkage, quenching the sidewalls of the article to a temperature that will provide a shrinkage of less than about 5% by volume and the above onset-of-shrinkage temperature of at least about 105 DEG C.
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