Polyester Resins for High-Strength Articles

Abstract

The present invention relates to slow-crystallizing, titanium-catalyzed polyethylene terephthalate resins that are useful for making high-strength, high-clarity bottles that possess improved resistance to stress cracking and thermal creep. The polyethylene terephthalate resins possess improved reheating profiles and are especially useful for making polyester articles that have exceptional clarity, dimensional stability, and thermal stability.

Description

CROSS-REFERENCE TO COMMONLY ASSIGNED APPLICATIONS [0001] This application is a continuation-in-part of commonly assigned U.S. patent application Ser. No. 10 / 996,789, for Polyester Preforms Useful for Enhanced Heat-Set Bottles, filed Nov. 24, 2004, (and published Jul. 14, 2005, as Publication No. 2005 / 0153086 A1), now U.S. Pat. No. 7,094,863, which itself is a continuation-in-part of commonly assigned U.S. patent application Ser. No. 10 / 850,918, for Slow-Crystallizing Polyester Resins, filed May 21, 2004, (and published Nov. 25, 2004, as Publication No. 2004 / 0236066 A1). [0002] This application is also a continuation-in-part of commonly assigned International Patent Application No. PCT / US04 / 39726 for Methods of Making Titanium-Catalyzed Polyethylene Terephthalate Resins, filed Nov. 24, 2004, (and published Nov. 3, 2005, as Publication No. WO 2005 / 103110), which itself is a continuation-in-part of U.S. patent application Ser. No. 10 / 850,269, for Methods of Making Titanium-Catalyzed Po...

AI Technical Summary

Benefits of technology

[0016] Accordingly, it is an object of the present invention to provide polyester resin that is capable of being efficiently formed into low-haze, high-clarity articles.

Problems solved by technology

Unfortunately, at normal production rates, most polyester resins cannot be efficiently formed into preforms and bottles that are suitable for hot-fill applications.

Most high-clarity polyester bottles do not possess the necessary dimensional stability to be hot-filled with product at temperatures between about 180° F. and 205° F., especially between about 195° F. and 205° F. In particular, at such elevated temperature conventional polyester bottles exhibit unacceptable shrinkage and haze.

In addition, polyester bottles that package carbonated beverages have been known to suffer stress cracking, which leads to catastrophic failure, or exhibit thermal instability (e.g., thermal creep), which can result in packaging deformations such as (e.g., fill-line drop, base rocking, and label distortion).

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