PROCESS FOR THE CONTINUOUS PRODUCTION OF VISCOSE RAYON YARNS HAVING HIGH DEGREE OF WHITE

摘要

Continuous prodn. of viscose rayon yarns comprises extruding viscose soln. into a coagulating bath, drawing and coagulating the filaments in the bath, and then finish-trea-ting the filaments while they mive in an almost helical path. The improvement comprises further coagulating the filaments after they are withdrawn from the first coagulating bath, until a coagulation index of not higher than 1 is reached. These obtd. filaments are treated with water having a Ph of 4.0-5.5, a Ca(2+) ion content of not higher than 1.0mg/l. The treatment is continued until the final yarn contains (max.values) 0.2% total sulfur, 40 ppm iron, 700 ppm Zinc, and 30 ppm lead.