초록 ▼

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°C. In the process preform preheated to a temperature suitable f

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°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°-250°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°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°C., even down to room temperature and lower, before the shrinkage resisting pressure is released from the hollow article.

대표청구항

A transparent hollow article of poly(ethylene terephthalate) having an inherent viscosity of at least 0.6 dl./gm., the body portion of said article being biaxially oriented and heat set and having a density over 1.392 g/cc and a volume shrinkage of less than about 6%.

A transparent hollow article of poly(ethylene terephthalate) having an inherent viscosity of at least 0.6 dl./gm., the body portion of said article being biaxially oriented and heat set and having a density over 1.392 g/cc and a volume shrinkage of less than about 6%.