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.     

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.     

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.     

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.     

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.     

Spinning viscose textile yarn into a zinc-aluminum-containing precipitation bath under manufacturing conditions

Conclusions Viscose textile yarn has been prepared by spinning in a zinc-aluminum-containing precipitation bath under manufacturing conditions.The yarn-spinning process in a zinc-aluminum-containing bath is stable, and is accompanied by an increased evolution of carbon disulfide and hydrogen sulfide.Viscose textile yarn spun in a zinc-aluminum-containing bath conforms to the All-Union State Standard and is characterized by a lower elongation and an increased swelling and shrinkage.Processes of warping and weaving the yarn have been carried out without any difficulties.O. M. Savchenko, senior engineer of the Klinsk Khimvolokno Industrial Association, also took part in this work.Translated from Khimicheskie Volokna, No. 6, pp. 34–35, November–December, 1988.     

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.     

Effect of jet stretch on polyacrylonitrile as‐spun fiber formation

In this article, the effect of jet stretch ratio on the extrudate die‐swell effect of polyacrylonitrile spinning solution and the structure and properties of as‐spun fibers was systematically analyzed by means of X‐ray diffraction (XRD), electron microprobe analysis, and the measurement of die‐swell ratio, boiling‐water shrinkage, porosity, mechanical properties analysis, etc. It revealed the formation mechanism of the die‐swell effect and spin orientation and its influences on the structure and properties of as‐spun fibers. It showed that with the increase of the jet stretch ratio the die‐swell ratio became smaller, both the degree of spin orientation and the crystallinity increased, the microstructure of as‐spun fibers became compact and homogeneous, and the cross section tended to be circular. As a result, the breaking tenacity of as‐spun fibers and resultant precursors all increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3348–3352, 2007     

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.     

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.     

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.     

Effect of the orientation stretch conditions for viscose textile yarn on its dyeing uniformity

Conclusions The tension of viscose textile yarn in the orientation stretching zone depends on the viscose parameters and the spinning conditions.A decrease in tension in orientation of yarn arriving at the centrifugal can increases the dyeing uniformity of the finished yarn.Translated from Khimicheskie Volokna, No. 3, pp. 35–36, May–June, 1983.     

Effect of orientation stretch on structure of a composite fibre based on high-density polyethylene and polybutylene terephthalate

Conclusions Due to the effect of the HDPE matrix in composite fibres based on HDPE-PBTP it is possible to draw the polybutylene terephthalate component to degrees of orientation which exceed the degree of orientation attained for pure PBTP.The introduction of chemical cross-links between the HDPE and the PBTP under radiative treatment permits one to expand the temperature service range of polyethylene fibres containing a small amount of the polyester.The possibility of transition from orthorhombic chain packing to a mesomorpohic state in a HDPE composite fibre on heating above the equilibrium melting point under isometric conditions has been demonstrated.Translated from Khimicheskie Volokna, No. 5, pp. 33–35, September–October, 1989.     

Role of precipitation bath components in the manufacture of viscose fibres

Conclusions An analysis has been made of data on structure formation processes in spinning viscose fibres and of the connection of the primary structure with the properties of the finished fibres and yarns.It has been shown that the attainment of high physicomechanical and operational properties of viscose fibres is possible by preventing premature crystallization of the cellulose in the freshly-spun gel-fibre.Retardation of the cellulose crystallization process in spinning viscose fibres is advisably effected as a result of reducing the activity of water in the precipitation bath.Translated from Khimicheskie Volokna, No. 1, pp. 8–13, January–February, 1986.     

Fire hazard properties of viscose fibre dusts

Conclusions The fractional composition of viscose fibre dust formed in the packaging division has been investigated.A quantitative determination of the combustible dust accuulated in the manufacturing packaging site has been carried out.It has beem shown that the viscose fibre dust fraction with a particle size less than 0.800 mm presents an explosion hazard, but the content of explosive dust does not exceed 6.1% of the total amount of dust. Dust which has not been separated into fractions presents no explosion hazard.To ensure safety from fire in viscose fibre packaging locations, it is necessary to use a mechanized dust-collection system.Translated from Khimicheskie Volokna, No. 6, pp. 44–45, November–December, 1989.