A STUDY ON SALTING OUT EFFECT OF INORGANIC SALTS IN THE WET-SPINNING OF POLYNOSIC FIBERS

In order to make clear the salting out effect of inorganic salts in the wet spinning of viscose fibers, coagulating effect of various inorganic salts in the spinning of polynosic fibers was studied.By the method previously reported, effects on stretching and deswelling of viscose filaments of Na2SO4, K2SO4, (NH4)2SO4, NaCl and NaNO3 were investigated.In the case of the sulfates, the coagulation of viscose filaments in earlier stage was suppressed with increasing salt concentration, and the suppression effect of salts became less as the salting out ability was larger. As for NaCl and NaNO3, coagulation in earlier stage was promoted with increasing salt concentration in the order of the salting out ability.As for the deswelling of viscose filaments in the latter stage, sulfates suppressed the deswelling in lower concentration and promoted it in higher concentration. In this case, the salts of high salting out ability showed high deswelling effect.On the contrary to sulfates, chloride and nitrate promoted deswelling in the latter stage in low concentration. However they suppressed the deswelling in higher concentration, and such trend was more marked in the salt of high salting out ability.