Polyester staple fibers and process for their preparation

Polyester staple fibers consisting of a polyester, 0.1 to 2.0 w.- % of an incompatible, melt processable, amorphous polymeric additive with a glass transition temperature of 90 to 170 DEG C and a melt viscosity/polyester component ratio of 1:1 to 10:1, and 0 to 5.0 weight % of usual additives. The polymeric additives in the staple fibers are present in the form of fibrils with a mean diameter of polyesters and the polymeric additives and optionally the usual additives and spinning at a speed of < 2500 m/min relative to form of spun fibers. Said are bundled together to form cables and stretched in aseparate drawframe to form separate reels of fiber, crimped, dried and cut to form staple fibers.