SIGNIFICANCE OF VISCOSITY OF VISCOSE IN RAYON INDUSTRY

Abstract

The degree of polymerization of alkali cellulose which is ready to be used for xanthation is very important in relation to the quality of the product. A series of experiments was carried out on semi-commercial of scale to find the effects of alkali cellulose prepared for xanthation upon viscosity of viscose and various properties of filaments.1. The viscosity of viscose is considerably affected by the distribution of DP, especially by the higher fractions. The viscose made from the alkali cellulose having uniform chain lengths of cellulose (Viscose A in Table I and Fig. I in test) showed the lower viscosity and excellent filament property. The tenacity and elongation of fibers made from this viscose were better than those of fibers made from the viscoses (B and C) having higher viscosities which are due to the greater variety in chain lengths of cellulose. (See Table I and Fig. I in text.)2. Three kinds of viscoses were prepared from alkali celluloses having lower mean DP (Viscose A in Table II in text) and higher mean DP (Viscose B and C in Table II in text). The DP's were controlled by aging. The filaments were spun from these three viscoses on semi-commercial scale. The properties of filaments, that is the crimp property, dry and wet tenacity, dry and wet elongation, and uniformity of tenacity of tenacity were measured. The viscose characterized by lower mean DP of cellulose is the best in all respects. (See Table II).3. Tire cords were spun with viscoses differing in viscosityies, and their tenacities were measured as a function of viscosity of viscose. (Table III and Fig. III)The viscoses having lower viscosities gave the cords of greater strengths.4. The higher viscosity of viscose due to the diversity in chain lengths of cellulose is not desirable. The aging of alkali cellulose should be done to sufficient extent to minimize the higher fractions. The optimum mean DP of cellulose of the alkali cellulose fit for xanthation was 330_??_350 under the conditions used in this experiments.The thought that the viscose characterized by the higher DP of cellulose gives the better filaments would be of little worth so far as the standard conditions of processing of viscose is concerned.