Patent ID: 6113997
Filing Date: 2000-09-05
Classification: B29C,C08G,Y10T

Abstract:
A process to prepare a co-polymer of polyethylene terephthalate (PET), and polyethylene isophthalate (Ihaving an acetaldehyde concentration equal to or less than about 1 PPM which process comprises the steps of:a) reacting ethylene glycol with terephthalic acid, or its ester, and isophthalic acid, or its ester, under constrained reaction conditions effective to prepare a melt phase co-polymer having an IV in the range of 0.38 dl/g to 0.46 dl/g and a diethylene glycol content of 5 mole % or less;b) recovering the melt phase co-polymer from step a) as the pre-polymer used in step c); andc) subjecting at least a portion of the pre-polymer recovered in step b) to elevated temperatures over a period of time to elevate the IV to a range of 0.60 dl/g to 0.90 dl/g to form said co-polymer of PET and IPA having an acetaldehyde content equal to or less than 1 PPM.