HIGH-STRENGTH FEED YARNS FOR SEWING YARNS, AND PROCESS FOR THEIR PREPARATION

摘要

of the disclosure: The invention relates to multifilament feed yarns from filament-forming polyesters for preparing high-strength multi-ply sewing yarns and to a process for their preparation. The claimed feed yarns are distinguished by a heat shrinkage at 200.degree.C of 5 to 7%, a reference extension at 45 cN/tex of less than 10% and a high relative solution viscosity. The preparation process is distinguished by a high windup speed in spinning which corresponds to a preorientation corresponding to a birefringence of more than 0.03 and by stabilization (setting) of the resulting filaments after stretching at temperatures of up to 225.degree.C.