To obtain a highly shrinkable polyester staple fiber, excellent in rich fullness, soft touch feeling and color fastness to light and useful for a knitted, a woven fabric, etc., by providing a shrinking stress with plural inflection points within a specific temperature range.
This highly shrinkable polyester staple fiber has ≥200mg/d maximum shrinking stress and 125-175°C peak temperature of maximum shrinking stress and the shrinking stress has three inflection points within the range of 50-190°C. The polyester is a copolyester prepared by copolymerizing isophthalic acid and 2,2-bis{4-(2-hydroxyethoxy)phenyl}propane as the third component. The staple fiber preferably has ≤17% shrinkage percentage in boiling water, 20-40% dry heat shrinkage percentage at 180°C, 90-95% crystal orientation degree (010 face) and 30-45 crystal size (010 face).
AONO SHOJI
KONNO YOSHIHIRO
