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 method for making a high density, partially crystalline, biaxially oriented, heat set, polyethylene terephthalate hollow container, the container having a body with oriented sidewalls, the method comprising the steps of: A. providing by blow molding a hollow article with oriented sidewalls, B. whi

A method for making a high density, partially crystalline, biaxially oriented, heat set, polyethylene terephthalate hollow container, the container having a body with oriented sidewalls, the method comprising the steps of: A. providing by blow molding a hollow article with oriented sidewalls, B. while the article is still under a shrinkage reducing pressure, increasing the density of the oriented sidewalls to at least about 1.391 g/cc by heating the sidewalls to a heat setting temperature equivalent to a temperature of about 220°C. to 250°C. to provide the density of at least about 1.391 g/cc, C. quenching the sidewalls while still under a shrinkage reducing pressure to provide the article with a shrinkage of less than about 5% of the volume and an onset of shrinkage temperature of at least about 105°C., the quenching being done at a temperature equivalent to that of about room temperature to 180°C. at a high heat setting temperature of 240°C., about 85°to 160°C. for a heat setting temperature of about 230°C., and about 120°C. to 150°C. for a lower heat setting temperature of about 220°C.