Improvement of Rayon by Continuous High-Temperature Steaming

Abstract

An apparatus was constructed, and heat treatment of rayon tow or sliver was carried out continuously using steam or water of 120° to 190° C for 15 to 80 sec Flash heating with saturated Steam of 7 to 14 kg/cm2 for 15 sec is sufficient to reduce the degree of swelling of rayon to the order of that of cotton. with negligible depolymerization Fine structure of the fully treated rayon is stable, and the reduced swelling and the mechanical properties do not change when the rayon comes into contact with water of 100° to 180° C Upon being immersed in caustic alkaline solutions, the treated rayon always has lower swelling compared to the untreated, and part of the net structure formed by the treatment remains undestroyed. In some cases increase in elongation and decrease in Young's modulus are brought about by an annealing effect at a sufficiently high temperature