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.     

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.     

Special features in spinning viscose fibre and yarns into a precipitation bath containing sulfuric acid and sodium sulfate

Conclusions The possibility of obtaining a viscose fibre with increased strength up to 25–28 cN/tex, and improved fatigue properties, a low-shrinkage fibre, or a fibre with less loss of strength in the wet state has been demonstrated under experimental conditions. The process of preparing a crimped viscose fibre has been checked out under manufacturing conditions.Eliminating zinc sulfate from the technological process and reducing the specific norms for consumption of sulfuric acid (thanks to the use of precipitation baths which are less concentrated in sulfuric acid) and for neutralizing agents affords an opportunity to reduce contamination of wastewater and to obtain ecological and economic benefits.Translated from Khimicheskie Volokna, No. 6, pp. 16–18, November–December, 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.     

Regeneration of KU-2-8 resin with precipitation baths from viscose manufacturing

Conclusions The process of regenerating KU-2-8 resin with precipitation baths from viscose manufacturing has been investigated as compared with regeneration with sulfuric acid.It has been found that desorption of zinc from the resin by precipitation baths is rather efficient, which makes it possible to use precipitation bath in the regeneration process instead of 10% sulfuric acid solution.It has been shown that a high content of organic contaminants in the precipitation baths (COD of 2000–5661 mg O₂/liter) does not affect the sorptive properties of KU-2-8 resin.Translated from Khimicheskie Volokna, No. 6, pp. 9–10, November–December, 1984.     

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 aluminum sulfate content of the precipitation bath on fibre physico-mechanical properties

Conclusions A high-strength fibre is obtained on spinning into precipitation baths containing 30–45 g/liter aluminum sulfate and 65–70 g/liter sulfuric acid, and having a bath density of 1.30–1.31 kg/m³. The relative breaking load of the fibre is 28 cN/tex, its elastic modulus in the wet state is 1380 MPa, and its elongation at break is 16%.At an aluminum sulfate content of 15–17 g/liter in the precipitation bath, an increase in sulfuric acid concentration from 90 to 129 g/liter leads to an increase in relative breaking load and the relative strength of fibre in a loop.Translated from Khimicheskie Volokna, No. 3, pp. 40–41, May–June, 1987.     

Rate of propagation and damping of ultrasonic waves in viscose textile yarns

Conclusions The effect of various technological factors in the spinning process (jet stretch, degree of orientation stretch, number of spinneret holes, and composition of the precipitation bath) on the rate of sound propagation and on the damping coefficient of ultrasonic waves in thin viscose textile fibres has been analyzed.A clear dependence of the indicated characteristics on technological factors has been detected. An explanation is given for the observed facts from the phenomenological positions of viscoelasticity.Translated from Khimicheskie Volokna, No. 1, pp. 30–32, January–February, 1984.     

Regeneration of coagulant from aluminum hydroxide containing precipitates from water-softening stations of viscose fibre plants

Conclusions Optimum parameters for the regeneration of aluminum from the sludge of the Kalininskii Khimvolokno PO water softening station with a 1.5% sulfuric acid solution have been determined. The regeneration efficiency is 85–95%.The fundamental possibility of cleaning up natural waters with regenerated coagulant has been shown by experiments on an experimental set-up.It is recommended to use gas purification wastewater, containing 10–20 g/liter of sulfuric acid, in viscose fibre plants as the reagent for acid treatment of the sludge from water-softening stations.Translated from Khimicheskie Volokna, No. 4, pp. 57–59, July–August, 1986.     

A method of monitoring sulfuric acid in the precipitation bath for manufacturing high-modulus viscose fibre

Conclusions The method of determining sulfuric acid content of a precipitation bath in the manufacture of high-modulus viscose fibre which is based on measuring the density and specific electrical conductivity of the bath under conditions of a stable technological process ensures a mean-squared error of a single measurement of ±0.23 g/dm³.This method can be used as an operative one for rapid analysis in determining sulfuric acid, and also in development of an industrial automatic analyzer.Translated from Khimicheskie Volokna, No. 3, p. 58, May–June, 1987.     

Some features of spinning cuprammonium fibres into precipitation baths containing calcium salts

Conclusions On the basis of data on precipitating power and the rate of dehydration of cuprammonium solutions of cellulose, the fundamental possibility has been demonstrated of spinning fibres from such solutions into precipitation baths containing calcium salts, using the technological scheme for viscose fibre manufacture.The dependence of the basic characteristics of the freshly-spun fibre on calcium salt content and temperature of the precipitation bath has been found.Moscow Textile Institute. Translated from Khimicheskie Volokna, No. 1, pp. 11–13, January–February, 1987.     

Some features of spinning viscose fibre and yarns into zinc-free precipitation baths

Conclusions The use of low-acid, bicomponent precipitation baths with additions of urea to the viscose, or also of baths containing such polyvalent metals as aluminum or magnesium, which permits one to obtain a fibre with improved physico-mechanical indices and fatigue properties at the spinning speeds which have been adopted in manufacturing is very promising in spinning viscose fibres and yarns into zinc-free precipitation baths.Replacement of the expensive zinc sulfate by cheaper reagents and the reduction in sulfuric acid consumption upon use of less concentrated precipitation baths permit one to obtain an economical advantage and eliminate the possibility of contaminating the water basin with toxic zinc.Translated from Khimicheskie Volokna, No. 2, pp. 51–53, March–April, 1988.     

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.     

Secondary energy resources in viscose fibre manufacturing

Conclusions An assessment of local exhausts in the manufacture of viscose fibre has been carried out.Thermotechnical properties of the local exhausts have been calculated.It has been found that exhausts from the lossening tank and finishing solution tanks, spent dryer air, and the off-gas from the unit for contact evaporation of precipitation bath are secondary energy resources in viscose fibre manufacture.Translated from Khimicheskie Volokna, No. 6, pp. 18–20, November–December, 1988.     

Extraction of zinc from low-concentration solutions in the manufacture of viscose fibers

Conclusions The process of zinc regeneration by the method of extraction from solutions close in composition to the wash water from viscose fiber manufacture has been studied under laboratory conditions.It is recommended to carry out the extraction of zinc with a 30% solution of D2EHPA in kerosene at a pH of 2–3 and an O:W ratio of 1:1.It is recommended to use a 15% sulfuric acid solution or a solution of precipitation bath as the re-extractant.Translated from Khimicheskie Volokna, No. 4, pp. 31–32, July–August, 1983.     

Effect of defects in high-modulus viscose fibres on their physicomechanical properties

Conclusions -- As a result of microscopic investigation of high-modulus viscose fibres, it has been found that the various types of defectiveness in them amounts to 90%.-- Four characteristic groups of fibre defects have been determined: breakdown in morphological structure - 25%; gas-bubble content - 20%; mechanical contaminants from the viscose - 25%; and mechanical contaminants from the precipitation bath - 20%.-- It has been shown that the presence of defects in the fibre reduces its strength characteristics from 7.7 to 33%, depending on the form of defect and increases nonuniformity in these figures.Translated from Khimicheskie Volokna, No. 4, pp. 49–51, July–August, 1991.     

Physicochemical bases of spinning viscose fibre of yarns into an aluminum sulfate precipitation bath

Conclusions The use of zinc-less aluminum sulfate precipitation baths in the manufacture of viscose fibre or yarn affords the following opportunities:Preparation of fibres with less strength loss in the moist state; low shrinkage fibres with a stable crimp which does not disappear on moist treatment; fibre with a high modulus and high strength in the moist state, that is, high-modulus viscose fibres and yarns;making wastewater harmless by replacing zinc salts by harmless aluminum salts and by increasing the degree of clarification and purification of the wastewater because of the content of aluminum sulfate in it, which acts as a coagulant;attainment of an ecological and economic benefit as a result of eliminating the expensive zinc sulfate from the technological process and reducing the specific norms for consumption of sulfuric acid, thanks to the use of low-concentration (in acid) precipitation baths.Translated from Khimicheskie Volokna, No. 2, pp. 34–36, March–April, 1986.     

Effect of urea additions on structure formation during the separation of hydrocellulose from viscose

Conclusions It has been shown by electron microscopy that the formation of two types of structure is possible on spinning model films from viscose into precipitation baths containing additions of urea: finely heterogeneous and cellular.The suggestion has been made that additions of urea to the precipitation bath retard viscose gelation processes.Translated from Khimicheskie Volokna, No. 4, pp. 25–26, July–August, 1986.     

Preparation of polyacrylonitrile fibre by spinning into organic baths

Conclusions -- The spinning of polyacrylonitrile copolymers into organic baths containing dimethyl sulfoxide and isopropyl alcohol has been investigated. It has been found that the optimum DMSO:IPA ratio in the precipitation bath is 60:40% by wt..-- It has been discovered that the strength of the spun yarn is higher the lower the jet stretch.-- The effect of temperature on orientation stretch ratio has been studied. It has been shown that the optimum temperature for heat stretching of PAN yarn lies in the range 155–160°C.-- The dimethyl sulfoxide content of yarn has been determined by technological transitions. In the final yarn it does not exceed 0.3–1.2% by wt.VNIIPV. Translated from Khimicheskie Volokna, No. 3, pp. 15–16, May–June, 1991.     

Special features in spinning fine viscose textile yarns

Conclusions Conditions which assure stability of the process of spinning a complex viscose yarn with an increased number of elementary filaments have been determined.It has been shown that stability of the process of spinning complex viscose textile yarn of 13.3 tex linear density with an increase in number of elementary filaments (>60) is increased on reducing the jet stretch, reducing the diameter of the spinneret holes from 0.09 to 0.06–0.05 mm, and bringing the distance between them from 1.4 to 0.5 mm.Translated from Khimicheskie Volokna, No. 3, pp. 39–40, May–June, 1984.