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.     

Effect of drying conditions on the properties of tire-cord yarn

Conclusions -- The drying conditions of technical yarn on a PN-300-IZ machine, where the yarn has been prepared from spinnerets having 2200 holes, has been investigated.-- The optimum yarn length on the drying cylinders has been determined with simultaneous and mandatory holding of the packages in a conditioning chamber before delivery to the twisting works.Translated from Khimicheskie Volokna, No. 5, pp. 27–29, September–October, 1990.     

Reducing water consumption in washing viscose textile yarn in packages

Conclusions The effect of specific flow rate of soft water on the intensity and extent of wash-out of viscose textile yarn in packages has been studied.A process of washing yarn on OK-I machines with a reduced consumption of soft water — down to 60 m³ per metric ton of yarn — has been developed and carried out in manufacturing.Translated from Khimicheskie Volokna, No. 1, pp. 44–45, January–February, 1987.     

Preparation of combined triacetate-polyamide yarns during the spinning process

Conclusions A technological process has been developed for the preparation of triacetate-polyamide pneumatically connected yarn on a machine for spinning triacetate yarn.Triacetate-polyamide pneumatically connected yarns have been processed into silk-like dress fabrics and tricotage cloth. The ease of yarn passage in textile processing, and also on warping and knitting equipment, is good. The development has been adopted for industrial development.Translated from Khimicheskie Volokna, No. 4, pp. 22–24, July–August, 1986.     

Role of slippage in the orientation stretch of Oksalon yarns

Conclusions It has been shown that in the continuous orientation stretching of Oksalon yarn in air, the deformation region is located close to the first stretch roll, including an arc of yarn slippage on it.The need to take the slippage arc into account in continuous yarn stretching has been demonstrated.By varying the frictional parameters of the first stretch roll, it is possible to achieve an increase in the strength of the finished yarn.Translated from Khimicheskie Volokna, No. 5, pp. 22–23, September–October, 1985.     

Modifier for viscose technical yarn based on cotton soapstock acids

Conclusions A new domestic modifier for viscose technical yarn has been synthesized — Amiprin KhS-20, based on distilled fatty acids from cotton soapstock.Specimens of viscose technical yarn have been prepared under the conditions of an experimental unit, using Amiprin KhS-20 modifier. The properties of the yarn obtained are close to those of yarn spun using Berol'-Visko 314 as a modifier.Translated from Khimicheskie Volokna, No. 3, pp. 46–47, May–June, 1989.     

Cooling yarns spun from polymer melts

Conclusions -- The effect of the component air streams on yarn uniformity with respect to linear density has been established. This has afforded opportunity to find an optimum regime for yarn cooling in spinning from polymer melts. Analysis of the pulsations in air streams has made it possible to determine the basic sources for their origin and ways to reduce them.-- A manufacturing control of the yarn cooling regime using anemometers has been proposed.-- A way of intensifying the yarn cooling regime using an air jet on the yarn section after its initial hardening has been described.-- It is recommended to use the method of investigating the process of yarn spinning by analysis of the component air streams in preparing fibres from polymer melts on any type of spinning equipment.Translated from Khimicheskie Volokna, No. 4, pp. 26–30, July–August, 1990.     

Hydrodynamic stability of yarn spinning from a melt of flexible-chain polymers

Conclusions Empirical relationships have been obtained which describe satisfactorily the effect of basic spinning parameters on nonuniformity in the diameter of the undrawn yarns; these make it possible to calculate optimum parameters which ensure an assigned level of yarn nonuniformity in diameter.It has been found that increasing the melt viscosity decreases the region of stable spinning.A connection has been found between nonuniformity of the undrawn yarn and the strength of the finished yarn: the strength of the drawn yarn is increased proportionately to the decrease in nonuniformity of the undrawn yarn in its diameter.Translated from Khimicheskie Volokna, No. 5, pp. 16–18, September–October, 1984.     

Some features of the structure of oriented polyethylene terephthalate yarns in the initial period of heat treatment

Conclusions The rearrangement in structure of PET yarn during short heat treatment times, that is, during the warming-up period and in the initial period of yarn heat treatment, has been examined from the evidence of isometric heating, IR spectroscopy, change in birefringence, density, and physicomechanical characteristics of yarn which has been heat treated in an air heating chamber at 200°C.It has been shown that during the time of warming up the yarn, structural changes are determined by relaxation processes. After heating, crystallization processes exert an important effect on the properties of the heat treated yarn. The complex character of the structural rearrangement leads to a nonhomogeneous change in physicomechanical properties of the yarn.Translated from Khimicheskie Volokna, No. 2, pp. 37–39, March–April, 1984.     

Deformation of man-made yarns during the process of their preparation

Conclusions The generality of deformation principles in processes of preparing man-made fibres has been examined.It has been suggested to examine yarn deformation during processes of yarn preparation as a superposition of two processes: deformation of yarn present in the free state (equivalent deformation) under the assigned technological conditions, and mechanical deformation.Methods of determining equivalent deformation have been proposed.The yarn equivalent deformation figure not only depends on technological process parameters, but also characterizes the maximum possible yarn deformation in the technological stage at hand, and also determines the kinetics of the deformation process.Translated from Khimicheskie Volokna, No. 4, pp. 27–29, July–August, 1987.     

A device for control of the operation of a lay-down mechanism

Conclusions An operative method of checking the kinematic parameters of batched yarn laydown units has been proposed, which makes it possible to evaluate the operation of yarn laydown devices without partial package winding.A mobile measuring block has been developed for recording the movement and velocity of a yarn guide which can be used under manufacturing conditions.Translated from Khimicheskie Volokna, No. 1, pp. 50–51, 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.     

Yarn laydown mechanism with additional travel of the yarn guide in reversal sections

Conclusions A yarn laydown mechanism has been proposed which makes it possible to reduce the loads acting on the yarn guide and traveler at the moment of reversal.The yarn laydown device described permits one to obtain a package with improved yarn distribution along its axis as compared with the yarn laydown devices of the MF-600-KSh24 and PN-1000-KS18 machines.Translated from Khimicheskie Volokna, No. 4, pp. 18–20, July–August, 1989.     

Finishing untwisted complex viscose yarn

Conclusions The effect of compositions based on polystyrene and paraffin on the physicomechanical properties of untwisted complex viscose yarn has been studied.It has been shown that a composition consisting of 2% by wt. PS-MD polystyrene and 0.8% paraffin, applied in a medium of tetrachloroethylene, is effective.On treating untwisted complex viscose yarn with this composition, physicomechanical properties are attained which conform to All-Union State Standard (GOST) 6-06-13-78; resistance to abrasion and the coefficient of yarn compactness are increased 1.9–2-fold; the coefficient of friction is reduced, and also good processing of the yarn into tricotage is ensured.Translated from Khimicheskie Volokna, No. 1, pp. 46–47, January–February, 1987.     

Effect of fluctuations in polymer melt temperature of linear density of yarn

Conclusions The effect of polymer melt temperature fluctuation at the inlet to the metering pump on nonuniformity in yarn linear density has been studied.It has been shown that considerable fluctuation in yarn linear density, caused by change in melt temperature, takes place also in individual working sites.A considerable difference in the temperature of the melt going to individual working sites of machines for spinning technical yarns has been discovered.Fluctuation in the linear density of yarn caused by variation in melt temperature at the inlet to the metering pump may reach 0.3–0.8% in spinning technical yarns, depending on the construction (group or individual) of the spinning machine melting devices.Translated from Khimicheskie Volokna, No. 5, pp. 45–47, September–October, 1984.     

Calculation of laydown spacing on cylindrical rolls with allowance for yarn displacement on the transition section

Conclusions A refined procedure has been proposed for calculating yarn laydown spacing on cylinders with allowance for geometrical factors and the coefficient of friction.A program has been set up for calculating yarn laydown spacing on cylindrical rolls (paired or unpaired) having intersecting axes.Translated from Khimicheskie Volokna, No. 1, pp. 41–44, January–February, 1986.     

Spinning cellulose acetate fibres in a nitrogen stream

Conclusions Results of studies on the spinning of acetate yarn in a current of nitrogen, at elevated concentrations of acetone vapor in the vapor-gas mixture in the spinning tower, have been presented.It has been shown that when acetate yarn is spun under the indicated conditions, the physicome chanical properties of the fibre are improved and the residual acetone content of the freshly spun yarn is reduced.Translated from Khimicheskie Volokna, No. 1, pp. 28–29, January–February, 1984.     

Effect of length of a complex yarn on its mechanism of failure in extension

Conclusions A quantitative characterization of nonsimultaneity in failure of the elementary filaments in a complex yarn on the right-hand part of the stretching diagram has been given.Some features of the failure of elementary filaments in a complex yarn at various sample clamped lengths have been examined.A method has been proposed for evaluating nonuniformity in breaking characteristics of elementary filaments in a complex yarn from the right-hand part of the stretching diagram at a low clamped length, and also from the ratio of the works of deformation to maximum loading and to complete yarn failure.Translated from Khimicheskie Volokna, No. 3, pp. 52–53, May–June, 1989.     

Structure and properties of dyed polypropylene yarn containing an addition of chemically colored low-molecular polycaproamide

Conclusions The thermal properties of PP yarns have been studied by determining their weight loss on heating. It has been shown that, by comparison with unmodified PP yarn, yarns containing an addition of chemically dyed LMPCA have improved thermal stability.Addition of chemically dyed LMPCA in the spinning of PP yarn leads to an increase in mean crystallinity and a decrease in the average size of yarn crystallites after jet stretch. The existence of two morphological forms of supermolecular structure has been shown by the electron microscopy method: spherulitic and oriented along the yarn axis.Translated from Khimicheskie Volokna, No. 6, pp. 20–21, November–December, 1986.     

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.