Process of hydrocellulose precipitation in dilute viscose wastes

Conclusions The kinetics of the process of hydrocellulose precipitation from dilute viscose wastes obtained in washing filter presses and regenerating filters with a built-up bed has been investigated.Dependences have been found which assure the possibility of predicting this process in the storage of dilute viscose wastes up to repeated use in the technological cycle.Translated from Khimicheskie Volokna, No. 6, pp. 12–13, November–December, 1988.     

Reconstruction of a frame filter press for bubbling wash-out of filter elements

Conclusions A construction has been described, and a procedure for calculating air distributing devices has been given, which will ensure uniform distribution of compressed air in the volume of a filter press during bubble washing of its charge.It has been found that the use of these devices permits one to increase the amount of viscose washed out of the filter material by 10%.Translated from Khimicheskie Volokna, No. 5, pp. 48–51, September–October, 1987.     

Calculation of viscose storage time

Conclusions The kinetics of viscose gelation at various temperatures has been studied experimentally.It has been recommended to carry out the calculation of the maximum storage time of a viscose by a formula which takes account of the change in ripeness index at various temperatures.Translated from Khimicheskie Volokna, No. 6, pp. 28–29, November–December, 1985.     

Filtering properties of media based on fibrous carbon materials

Conclusions The filtering properties of specimens of carbon fibre materials prepared at final carbonization temperatures of 500 and 900°C, from a nonwoven material based on viscose fibre waste, have been investigated.The possibility of increasing the length of a filter working cycle two- to threefold with a charge of carbon fibre material as compared with the filtration time through a cotton charge, with an identical quality of viscose clarification, has been demonstrated.Translated from Khimicheskie Volokna, No. 2, pp. 53–55, March–April, 1985.     

Properties of complex viscose yarns containing elementary filaments of different linear density

Conclusions Breaking loads and deformation properties of complex viscose yarns containing elementary filaments of different linear density have been studied.The change in structural nonuniformity over a cross-section of viscose textile filaments of different linear density has been quantitatively evaluated.Translated from Khimicheskie Volokna, No. 3, pp. 47–48, May–June, 1985.     

Effect of finishing on chemical and structural changes in viscose fibres

Conclusions -- Comparative studies have been carried out of the change in properties of ordinary viscose fibre and high-modulus viscose fibre during the finishing process.-- It has been shown that oxidative degradation and hydrolysis take place more intensively during final regeneration and alkali desulfuration and to a larger degree this is characteristic of ordinary viscose fibre; thereupon, additional crystallization of the cellulose takes place.Translated from Khimicheskie Volokna, No. 5, pp. 40–42, September–October, 1991.     

Effect of alkaline earth metal or iron contaminants on properties of viscose

Conclusions The effect of salts of alkaline earth metals and iron on the physico-chemical indices of viscose — viscosity, ripeness, and filterability — has been investigated.In amounts which exceed the content allowed by the All-Union State Standard in viscose by a factor of 3–4, calcium and magnesium ions do not cause a significant impairment in the physico-chemical indices of the viscose.Even at a content of 28 mg/liter, the presence of trivalent iron salts in a viscose causes a sharp impairment in its filterability, especially on prolonged ripening.Strict control of the trivalent iron content of viscose during the process of preparing it for spinning is necessary.Siberian Technological Institute. Translated from Kimicheskie Volokna, No. 2, pp. 17–18, March–April, 1987.     

Intensification of ripening of viscose with the aid of an optimization equation for the process

Conclusions It has been shown that in the intensification of the ripening process of viscose the optimum temperature curve, which allows viscose to be obtained prior to spinning with certain values of ripeness and rate of its change, there are two periods corresponding to heating and cooling of the viscose. A method has been described for determining the optimum temperature curve with the help of an ACM. We have dealt with a definite production situation for which tables have been calculated and formulae obtained, which for certain initial and final values of the ripeness and temperature of the viscose allow a determination of the optimum temperature—time conditions for the ripening process to be made.All-Union Synthetic Fibre Research Institute (VNIIV). Moscow Institute of Chemical Machinery (MIKhM). Translated from Khimicheskie Volokna, No. 3, pp. 22–24, May–June, 1969.     

Degradation of viscose fibres in the finishing process and in service

Conclusions The change in degree of polymerization, loss in weight, and buildup of carbonyl and carboxyl groups have been investigated in boiling, bleaching, and washing ordinary viscose fibre, Siblon high-modulus fibre, and cotton.It has been found that Siblon high-modulus viscose fibre is preferable for blends with cotton with respect to resistance to degradation.Translated from Khimicheskie Volokna, No. 5, pp. 36–37, September–October, 1984.     

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.     

Use of diluted viscose waste in the process of preparing complex yarn for aircraft fabrics

Conclusions The possibility has been established of using dilute viscose wastes in the process of preparing a spinning solution for spinning complex viscose yarns which are used in the manufacture of aircraft fabrics.Empirical equations have been obtained for calculating the change with time of ripeness indices and of free NaOH content of viscoses having an -cellulose concentration of 5.0–8.4% by wt., plus calculated dependences which ensure determining the optimum ripeness index for spinning for viscoses which have been diluted in the range indicated.It has been shown that, with decrease in -cellulose and NaOH content of the spinning solution, the stiffness of complex viscose yarn is increased.Translated from Khimicheskie Volokna, No. 3, pp. 48–50, May–June, 1986.     

Viscose filtration (review)

Conclusion This review of the relevant literature showed that the mechanism of viscose filtration differs from the filtration processes for other solutions in that it is largely of the clogging type, i.e., it proceeds in the inside layers of the filter, the result being that the capillary system of the filter material undergoes a change with a rapid increase in the resistance in the filtration process as a consequence. The degree of clogging depends on the ratio between the size of the contaminating particles and the diameter of the pores of the filter screen.The method of filtration may undergo a change in the future. Filtration proceeds in accordance with more than one mechanism simultaneously. The filtration process can be accelerated by using auxiliary substances while the degree of purity of the viscose can be increased by filtration through a nonwoven material.Woven filter materials and the auxiliary substances used in viscose filtration, polyvinyl chloride powder and fine-cut modified fibres, entrap mainly the particles larger than 10 . Nonwoven materials give a higher degree of purification so that in the second stage of the process the viscose should be filtered through a high-bulk nonwoven material.The new methods of analysis involving a direct count of the particles make it possible to investigate the quality of the viscose and the nature of the particles in more precise detail and to decide the conditions of filtration accordingly. The methods are inadequate, however, for an analysis of the quality of the filtered viscose.Although the number of publications dealing with the filtration of viscose for production purposes is quite large, an analysis of the relevant literature shows that not enough research was done on filtration through auxiliary substances, and on the influence of the properties of the filter material and the ratio of the size of the contaminating particles to the diameter of the pores of the filter screen on the degree of viscose purification; information about the nature of the gel particles and the influence of their size and type on the physicomechanical properties of the fibre is limited.Translated from Khimicheskie Volokna, No. 3, pp. 33–38, May–June, 1978.     

Deformation properties of complex viscose yarns before and after relaxation in water

Conclusions The character of change in deformatic properties of complex viscose yarns — breaking load and elongation — as a function of the magnitude of the work of deformation to break has been established.The suggestion has been made that it is possible to use this dependence to evaluate yarn defectiveness.Translated from Khimicheskie Volokna, No. 6, pp. 43–45, November–December, 1986.     

Kinetics of change in polymer concentration in spinning viscose yarn

Conclusions A method of investigating the change in polymer concentration in spinning viscose yarns by the wet method as a function of the compositions of the spinning solutions and the precipitation baths has been proposed.Translated from Khimicheskie Volokna, No. 6, pp. 33–35, November–December, 1986.     

Reducing technological viscose losses in recharging plate-and-frame filter presses

Conclusions With the object of collecting the viscose wastes which are formed in recharging filters, a preliminary bubbling wash of the filter presses is advisable.The advantages of the bubbling wash over straight-through washing consist in shortening the time for this technological operation and in more complete wash-out of the viscose from the filter cloth, which makes it possible to save cellulose and sodium hydroxide, reduce the amount of water consumed in washing the filter cloth, and reduce the viscose content of the waste water.Translated from Khimicheskie Volokna, No. 4, pp. 25–26, July–August, 1983.     

Properties of viscose prepared from modified cellulose

Conclusions Some basic characteristics of viscose prepared from radiation-modified cellulose as compared with standard viscose have been determined.It has been shown that viscose from RMC has an increased coagulation resistance and increased physicochemical uniformity as compared with standard viscose of analogous composition.Translated from Khimicheskie Volokna, No. 2, pp. 32–34, March–April, 1990.     

Effect of the concentration of the textile-auxiliary solution on the drying time of viscose fibres

Conclusions A dependence of the change in moisture content of viscose yarn on the concentration of the treating textile-auxiliary substance solution has been obtained analytically.It has been shown that a change in concentration of the treating solution from 1 to 20% by wt. leads to a decrease in yarn moisture content by a factor of 25, and the drying time in treating with a 20% solution of a paraffin size is reduced by a factor of 7.Translated from Khimicheskie Volokna, No. 6, pp. 27–28, November–December, 1985.     

Tests of a filter with a filtering layer of synthetic fibre waste

Conclusions A fibre filter ensures thorough clean-up of wastewater from viscose fibre manufacturing from suspended particles and dispersed sulfur.The high rate of filtration of the fibre filter (27 m/h), reduction in water consumption, and 30% reduction in time for washing the filter show that economy can be achieved by replacing the quartz filter with a fibre one in the scheme of wastewater clean-up.Translated from Khimicheskie Volokna, No. 5, pp. 49–50, September–October, 1983.     

Possibility of using acrylic compounds to finish viscose textile yarn

Conclusions The possibility of using acrylic compounds to finish viscose yarn has been investigated. It has been shown that polybutyl methacrylate in an amount of 0.5–4% by wt., with addition of 0.1–0.8% paraffin, is effective.The use of this composition reduces the coefficient of friction, increases the compactness coefficient and resistance of the viscose yarn to abrasion, ensures its ability to be processed, and also ensures uniformity in dyeing and also ensures practically complete wash-out of the composition in finishing tricotage fabric.Translated from Khimicheskie Volokna, No. 5, pp. 39–41, September–October, 1989.     

Sorption of water vapor by Siblon fibre

Conclusions Water vapor sorption and desorption isotherms for Siblon high-modulus viscose fibre have been obtained at 20°C.It has been shown that Siblon has a higher absorptive power for water vapor as compared with other viscose fibres, textile yarn, and cotton cellulose.Translated from Khimicheskie Volokna, No. 5, pp. 40–41, September–October, 1987.