SCREW DESIGNS HAVING IMPROVED PERFORMANCE WITH LOW MELTING PET RESINS

摘要

pDisclosed is a process for a melt processing a polyethylene terephthalate resin characterized by one or more of the following. The polyester particles may have at least two melting peaks wherein one of the at least two melting peaks is a low peak melting point with a range from 140° C. to 220° C., or from 140° C. to 230° C., and having a melting endothermic area of at least the absolute value of 1 J/g. The polyester particles may have one or more melting peaks at least one of which when measured on a DSC first heating scan has a heating curve departing from a baseline in the endothermic direction at a temperature of less than or equal to 200° C. The polyester particles may have an It.V. at their surface which is less than 0.25 dL/g higher than the It.V. at their center. The polyester particles may have not been solid stated. The melt processing device comprises a screw with a total length, L, a feed zone length in the range from 0.16L and 0.45L, a taper angle, phi, in the range from 0.5 degrees and 5.0 degrees and a compression ratio, CR, in the range from 2.0 and 5.0./p [US2009315219A1]