Highly-shrinkable polyester fiber, process for preparation thereof, blended polyester yarn and process for preparation thereof.

摘要

A highly-shrinkable polyester fiber composed of a polyester comprising ethylene terephthalate units as main recurring units and having a birefringence ( DELTA n) of from 0.130 to 0.165, wherein the boiling water shrinkage is at least 30% and the peak temperature and peak value of the thermal stress are 90 to 105 DEG C and at least 0.4 g/de, respectively. The fiber has excellent shrinkability as well as high heat resistance, dimensional stability and alkali resistance and provides a blended polyester yarn excellent in bulkiness and hand.