An electrochemical method of regenerating the precipitation bath in the manufacture of viscose fibres

Conclusions The electrochemical method of regenerating the precipitation bath by electrolysis of sodium sulfate permits one to return to manufacturing operations 0.55 metric ton of sulfuric acid and 0.45 metric ton of sodium hydroxide calculated per metric ton of ordinary viscose fibre and 0.91 metric ton of sulfuric acid and 0.74 metric ton of NaOH per metric ton of high-modulus fibre.The quantity of crystallized and dewatered sodium sulfate has been reduced by 50%. The need for degassing and filtering the bath which is delivered to the anode compartment has been eliminated, and also the removal of excess organic substances (hemicelluloses, surfaceactive substances, or modifiers) from the precipitation bath is ensured, due to oxidative processes which take place during the electrolysis.Translated from Khimicheskie Volokna, No. 3, pp. 38–40, May–June, 1985.     

Separate determination of the components of the precipitation bath in viscose fibre manufacturing

Conclusions A method based on high-frequency titration of bath samples with barium acetate and with sodium hydroxide is recommended for the determination of the contents of the components of the precipitation bath.The time for an analysis is 30–40 min, and the reproducibility is good.Translated from Khimicheskie Volokna, No. 6, pp. 57–58, November–December, 1983.     

Stablization of tahe viscose in the manufacture of artificial fibres

Conclusions A structure and algorithm have been developed for fan adaptive system for stabilizing the composition of viscose in the manufacture of artificial fibres.This system has been introduced into the ACS TP for the manufacture of viscose tire cord at the Svetlogordsk Khimvolokno PO.Translated from Khimicheskie Volokna, No. 5, pp. 25–26, September–October, 1986.     

Properties and structure of precipitation baths in viscose manufacture

Conclusions To spin viscose fibre, it is necessary to choose such a composition of the precipitation bath solutions that the water structure in them is broken up; that is, in electrolyte concentration they are above the transition region.In a bicomponent bath, that is, in solutions of the H₂SO₄-Na₂SO₄-H₂O system, it is not possible to improve viscose fibre spinning conditions by changing the composition and concentrations of the components (without additions of other ions or large quantities of organic substances).To select the optimum precipitation bath composition and replace scarce zinc, it is recommended to use magnesium sulfate or aluminum sulfate.Translated from Khimicheskie Volokna, No. 4, pp. 10–13, July–August, 1986.     

Effect of sulfuric acid concentration in the precipitation bath on the efficiency of modifier action in the preparation of viscose fibres

Conclusions The modifying power of polyethylene glycols (PEG-35 and PEG-115), an ethoxylated amine, dimethylamine, and sodium carbamate has been investigated under conditions which model the spinning of viscose fibres.It has been shown that the maximum modifying power is observed at a sulfuric acid content of 40–60 g/liter in the precipitation bath.On the basis of an analysis of diffusion kinetics, the suggestion has been made that the weak modifying ability at a sulfuric acid concentration below 40 g/liter in the precipitation bath is explained by an alkaline medium; and the weak modifying power at a concentration above 60 g/liter, by a strongly acid medium on the surface of the forming fibre.Translated from Khimicheskie Volokna, No. 3, pp. 48–49, May–June, 1989.     

Spinning viscose technical yarn into a bicomponent precipitation bath

Conclusions -- The possibility has been demonstrated of preparing viscose yarn by the centrifugal method from a viscose containing additions of urea by spinning into a bicomponent precipitation bath containing sulfuric acid and sodium sulfate.-- Optimum conditions for spinning viscose yarn have been established: a sulfuric acid content of 115 g/l in the precipitation bath, a urea content of 2.5% based on weight of -cellulose in the viscose, and an orientation stretch of 22%.-- Specimens of viscose yarn having a linear density of 13.3 tex have been prepared with a relative breaking load of up to 19 cN/tex, an elongation at break of 17–19%, and a mean squared deviation in dyeing nonuniformity of 0.8–1.0.Translated from Khimicheskie Volokna, No. 4, pp. 33–34, July–August, 1990.     

Effect of precipitation bath parameters on the spinning of viscose yarn

Conclusions A criterion for complex evaluation of the effect of precipitation bath activity on fiber-forming processes in spinning viscose textile yarn has been established.The possibility of predicting the optimum composition of the precipitation bath within a broad range of sulfuric acid and sodium sulfate content has been shown.Translated from Khimicheskie Volokna, No. 1, pp. 29–30, January–February, 1985.     

Effect of precipitation bath composition on the swelling of viscose textile yarn

Conclusions The dependence of the degree of swelling of freshly spun viscose textile yarn (primary swelling) and of the finished yarn (secondary swelling) on precipitation bath composition has been investigated by the mathematical planning method, using a three-factor experiment.The optimum precipitation bath composition has been found, which ensures a minimum degree of swelling of viscose textile yarn and, consequently, a more uniform distribution of yarn properties over the cake layers, which has made it possible to increase cake weight.Translated from Khimicheskie Volokna, No. 4, pp. 26–28, July–August, 1985.     

Effect of precipitation bath composition on the process of spinning viscose yarn

Conclusions A connection between the change in characteristics of the viscose yarn spinning process and the structure of the precipitation bath solutions has been shown.To create optimum conditions for spinning viscose yarns, a bath is necessary in whose solutions the structure of water is broken up.Possibilities for improving conditions for spinning yarns into precipitation baths containing the H₂SO₄-Na₂SO₄-H₂O system are limited by the solubility of sodium sulfate.Translated from Khimicheskie Volokna, No. 1, pp. 40–42, January–February, 1987.     

Spinning viscose textile into a precipitation bath containing zinc and aluminum

Conclusions A viscose textile yarn was been prepared by spinning viscose into a zinc-aluminum-containing precipitation bath.Yarn elongation is increased with increase in zinc sulfate content and with decrease in the aluminum sulfate content of the precipitation bath.Jet stretch increases strength and reduces yarn elongation.Yarn strength and elongation increase with rise in viscose ripeness.Translated from Khimicheskie Volokna, No. 3, pp. 44–46, May–June, 1988.