Results of studying yarn tension on type PN-1000-KS18 two-yarn machines

Conclusions Tension force depends on the adhesion of the freshly spun fibres with the surfaces of the spinning rolls, and is determined as a function of the linear density of the yarn, the composition of the lubricant preparation, the diameter of the spinning rolls, the trajectory of the yarn movements, and the angle encompassed on the spinning rolls by the yarn. These parameters are the starting points for designing machines for the take-up and winding of freshly spun yarns and should be reflected in customer requirements.Replacement of the upper spinning roll by a roll with a cylindrical surface for yarn A and a conical surface for yarn B at an appropriate conicity, and also upon use of lower spinning rolls of identical diameter makes it possible to regulate the yarns B tension in a range which is adequate for equalizing tension within allowable limits for yarns of various assortments.The operation of positions in the twisting and stretching machine and slippage of yarn with respect to the rolls may be judged from the linear density of the freshly-spun and drawn yarn.Determination of the state of working units of the take-up and winding machine is possible from tension measurements.Translated from Khimicheskie Volokna, No. 5, pp. 53–55, September–October, 1989.     

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.     

Heating of synthetic yarns during the process of stretching and heat-setting

Conclusions It has been proposed to determine the mean yarn temperature in the cold stretching zone, and also the power which it is necessary to supply to the yarn from the stretching mechanism side, from stretching process technological data.The coefficients of friction of polyamide and polyester complex yarns on pyroceram rolls and stretch cylinders have been determined experimentally.Translated from Khimicheskie Volokna, No. 3, pp. 44–46, May–June, 1987.     

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.     

The ratio of the travelling speeds of the coagulating bath and the filament in vertical tubes on continuous machines

Conclusions 1. Analysis of the experimental and calculated results shows that to make a good quality cord yarn, and for regular running of the process during spinning with negative spinneret stretching, the coagulating bath should have a speed somewhat lower than that of the yarn being spun. In this case the flow of the liquid creates the most favourable conditions for spinning the yarn.2. The optimum ratios of the yarn and coagulating bath speeds depend both on the process parameters (inverse dependency on the amount of spinneret stretch), and also on the configuration of the spinning tube.Moscow Textile Institute. Translated from Khimicheskie Volokna, No. 5, pp. 25–26, September–October, 1969.     

High-speed spinning of polyester yarns

Conclusions An estimate of the mean lengthwise velocity gradient has been made at 3000 and 4500 m/min); this rises with increase in velocity and degree of stretch, and also as the elementary filaments become thinner.The effect of yarn stretching conditions on change in yarn orientation has been shown for 7, 15, and 25 tex yarns in high-speed spinning.Translated from Khimicheskie Volokna, No. 5, pp. 27–28, September–October, 1985.     

Mechanism of fibril extension in a deformable composite yarn of the “matrix-fibril” type

Conclusions For composite yarns of the matrix-fibril structure, the fibril distribution which is attained in the stretching process with respect to stretch ratio (and correspondingly with respect to mean degree of molecular orientation) is brought about the original fibril distribution by size (diameter and length).In the orientation stretching of a composite yarn, the stretching of fibrils takes place with a stretch ratio equal to or less than the stretch ratio of the matrix.Translated from Khimicheskie Volokna, No. 2, pp. 3–5, March–April, 1989.     

Effect of stretching conditions on the properties of polyester textile yarns

Conclusions By varying the temperature of the heating roll and, correspondingly, the magnitude of the natural stretch ratio, one can obtain a required level of change in shrinkage in a definite sequence; and by periodicity of removal of the yarn being stretched from the heater, one may obtain lengthwise variation in shrinkage of polyester textile yarn.Translated from Khimicheskie Volokna, No. 2, pp. 37–39, March–April, 1987.     

Raising the quality of technical yarn by improving the state of KV-III-250KA twisting and stretching machines

Conclusions As a result of improving the technical state of the KV-III-250KA machine, a stabilization in the physicomechanical properties of polycaproamide tire cord yarn has been achieved.Installation of lower stretch rolls with a gas-plasma sprayed hard alloy coating on the KV-III-250KA machines makes it possible to considerably raise the quality level of the drawn tire core yarn.Translated from Khimicheskie Volokna, No. 5, pp. 56–57, September–October, 1989.     

Special features in spinning fibres from solutions of stiff-chain polymers through an air gap

Conclusions -- The spinning of yarn from sulfuric acid solutions of poly-p-phenylene terephthalamide and poly-p-phenylene-1,3,4-oxadiazole through an air gap at a high stretch ratio is unstable because of the onset of pulsations in jet diameter, which are stable with time in frequency and amplitude and which is known for polymer melts as stretching resonance. Resonance parameters have been obtained in the use of a series of model channels as spinnerets, where these had various ratios of length to diameter and various forms of the entry zone.-- The onset of resonance depends on conditions for the flow of the polymer solutions in the spinneret channel and on the lengthwise temperature gradient in the air gap.Translated from Khimicheskie Volokna, No. 1, pp. 32–34, January–February, 1991.     

Some special features in drying ordinary viscose textile yarns

Conclusions On machines for continuous spinning, finishing, drying, and twisting of viscose textile yarns without intermediate conditioning, the most favorable yarn moisture range is 10–13%; this ensures optimum physicomechanical indices and twist uniformity.In conductive-convective drying of viscose textile yarns which are in the drawn state, evaporation of moisture from the interfiber space takes place more slowly, the larger the number and the less the linear density of the elementary filaments in the complex yarn.Translated from Khimicheskie Volokna, No. 1, pp. 39–41, January–February, 1985.     

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.     

Stretching induced phase transformations in melt extruded poly(vinylidene fluoride) cast films: Effect of cast roll temperature and speed

Melt extruded poly(vinylidene fluoride) cast films were prepared at different cast roll temperatures and speeds to study the effect of casting temperature and preorientation of the melt on the α‐ to β‐phase transformation in these films after uniaxial stretching. X‐ray and fourier transform infrared spectroscopy were used to identify the crystalline phases. The unstretched films were characterized using small angle light scattering (SALS). The films were stretched to a stretch ratio of 4.2 and at 80°C. Birefringence of the films and the fraction of β‐phase [F(β)] formed after uniaxial stretching increased with stretch ratio. The films showed increased crystallinity after stretching. For the films prepared at different cast roll temperatures, there was little change in F(β) in the films having a cast roll temperature between 75 and 120°C, but for the film with a cast roll temperature of 130°C F(β) decreased considerably. For the films prepared at different cast roll speeds, the F(β) increased with stretch ratio as well as with cast roll speed for a fixed stretch ratio. The primary effect of changing both the parameters is a change in the average spherulitic radius (R), in the unstretched films measured using SALS. The F(β) obtained correlated well with R and lower spherulitic radii resulted in the higher conversion to the β‐phase. POLYM. ENG. SCI., 47:1992–2004, 2007. © 2007 Society of Plastics Engineers     

Calculation of the heat-up of synthetic fibres during the heat-stretching process

Conclusions A computer calculation of the process of synthetic yarn heat-up during heat stretching which is based on using the thermal conductivity equation in the difference form permits one to analyse yarn heat-up through its depth, and also to take account of change in yarn tension and in temperature of the heating elements.The results obtained can be used to estimate the heat-up of yarns of any linear density.Translated from Khimicheskie Volokna, No. 5, pp. 13–14, September–October, 1984.     

Service properties of chrome-plated surface of fibre-guiding equipment in the KV-III-250 KA machine

Conclusions The effect of the form of chromium-plated fibre-conducting equipment in the KV-III-250 KA machine on the properties of polycaproamide yarn of 187 tex linear density which has been treated with lubricant Teprém-6 is described.It is recommended to use worn-in stretch rolls with a matte surface for their lower stretch rolls; for the heat-plasticizers and other parts, where it is advisable to have a low coefficient of yarn friction, it is recommended to use a shiny-rough surface.Translated from Khimicheskie Volokna, No. 2, pp. 57–59, March–April 1984.     

Orientation stretching of polyester fibre

Conclusions Orientation stretching of Lavsan fibre on twisting-stretching machines takes place in two stages, the ratio between them depending on the temperature conditions in each zone. The thread tenacity depends mainly on the overall stretching frequency, which remains constant over a fairly wide temperature range for a given fibre. The temperature conditions of stretching also determine such fibre properties as the degree of shrinkage and crystallinity.All-Union Scientific-Research Institute for Glass Fibre (VIISV). Translated from Khimicheskie Volokna, No. 6, pp. 13–15, November–December, 1969.     

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.     

78dtex/48f锦纶6拉伸变形竹节丝的生产工艺

采用锦纶6一步纺丝法生产锦纶预取向丝(POY),并通过加捻拉伸变形工艺,重点控制热箱温度、拉伸倍数以及加弹速度,制备具有竹节效果的锦纶拉伸变形丝(DTY)。对加弹后的纱线进行织袜及性能测试,结果表明:控制热箱温度为205℃,加弹速度为350 m/min,牵伸倍数为1.05,并合理控制假捻盘片组合、D/Y比及超喂率,可以制备出具有竹节效果的78 dtex/48 PA6 DTY竹节丝,织物镂空效果明显。     

Determination of the shear modulus of yarns in twisting

Conclusions Experimental data on the effect of linear density and yarn structure on shear modulus in twisting polycaproamide yarns support an inverse dependence of the shear modulus in twisting on linear density and on number of elementary filaments in the complex yarn.It has been demonstrated theoretically and experimentally that the calculational formula in the VNIIV procedure is suitable only for determining the shear modulus in twisting monofilam and is not suitable for calculating the shear modulus of complex yarns.An equation has been derived which is recommended for determining the shear modulus of yarns of various structures using a twisting pendulum.Translated from Khimicheskie Volokna, No. 1, pp. 37–38, January–February, 1986.     

Effect of spinning conditions on the stationary regime region in stretching a jet of a solution of poly-p-phenyleneterephthalamide in an air gap

Conclusions -- The spinning of a yarn from sulfuric acid solutions of poly-p-phenyleneterephthalamide through an air gap in the region of high stretch ratios is unstable because of the onset of pulsations in jet diameter, which is known for polymer melts as stretching resonance.-- The onset of resonance depends on the diameter of the holes in standard cup-shaped spinnerets in the range 0.06–0.1 mm.-- The region of stationary jet-stretching regimes without resonance is considerably expanded in the case of forced cooling of the jet of PPTA solution in the air gap.Deceased.Translated from Khimicheskie Volokna, No. 2, pp. 17–19, March–April, 1993.