Zinc-free preparation of rayon fibers

摘要

Rayon fibers having high wet modulus, low wet elongation and low caustic solubility are prepared from an unmodified viscose spinning solution by spinning the viscose solution into a zinc-free coagulation bath containing at least 125 g/l of Na2SO4, at least 125 g/l of (NH4)2SO4 and less than 100 g/l of H2SO4 while the bath is at a temperature above 40 DEG C. The coagulated filament is then stretched in a secondary bath maintained at a temperature over 70 DEG C.