Use of chemically dyed low-molecular polycaproamide to prepare dyed polypropylene yarn

Conclusions Chemically dyed LMPCA have been synthesized by the direct reaction of three types of active dyes with LMPCA at temperatures below 100°C for 3–6 h; they contain up to 20–40% (of the weight of the dyed product) of chemically bonded dye.The chemically colored LMPCA are soluble in solvents for LMPCA; they form a finely crystalline structure, have a melting point close to that of the starting LMPCA, and have significantly improved thermal properties.Upon addition of chemically dyed LMPCA to PP flake, colored undrawn monofilaments were formed, whose strength at an additive content of 10% on the weight of PP did not differ from the strength of monofilament spun under analogous conditions, and the specific bulk electrica resistance was 2–10 times smaller.Translated from Khimicheskie Volokna, No. 6, pp. 22–24, November–December, 1986.     

Properties and application of Ovilan-2 texturized viscose yarns

Conclusions Ovilan-2 texturized viscose yarn has satisfactory physicomechanical characteristics, whose uniformity is improved on doubling two or more yarns.The high-bulk structure of Ovilan-2 yarns is stable to hot-moist or mechanical actions during the processing operations.Ovilan-2 yarn which has been dyed in bulk corresponds to the requirements imposed on a raw material for the manufacture of double-weave Jacquard carpeting.Translated from Khimicheskie Volokna, No. 3, pp. 43–45, May–June, 1983.     

Mechanism and kinetics of shrinking of texturized composite fibres having a matrix-fibrillar structure

Conclusions The mechanism and kinetics of shrinkage of complex texturized composite yarns having a matrix-fibrillar structure, and also of yarn shrinkage in a crimp, have been studied.It has been shown that the behavior of a yarn in a crimp on heating, and also the shrinkage of complex texturized yarns, depends considerably on the disposition of the polyethylene fibrils in the polycaproamide matrix.Spinning yarns with a nonuniform disposition of fibrils in the matrix permits one to obtain texturized yarns with a combined spatial-planar twist and an elevated bulkiness.Translated from Khimicheskie Volokna, No. 3, pp. 32–34, May–June, 1988.     

Radiation resistance of acetate and triacetate yarns

Conclusions The radiation resistance of acetate and triacetate yarns has been studied. It has been shown that, in retention of physico-mechanical properties at a radiation dose of 10 Mrad, the yarns may be placed in the series: acetate, dull > acetate, bright > acetate dyed > triacetate, bright.It has been found that irradiation of acetate yarns with small doses leads to an increase in their resistance to abrasion with practically complete retention of the original strength. The effect of radiative improvement is higher in acetate yarns which have been dulled with titanium dioxide.Translated from Khimicheskie Volokna, No. 3, pp. 31–32, May–June, 1988.     

Normalization of specific electrical resistance characteristic of complex acetate yarns

Conclusions It has been shown that, regardless of the type of lubricant or its content on acetate textile yarn, an essentially identical decrease in specific electrical resistance is observed.The specific electrical resistance of acetate yarns which have been treated with lubricants lies in a range which ensures normal processing of such yarns into textile articles.Translated from Khimicheskie Volokna, No. 6, pp. 20–21, November–December, 1989.     

Preparation of Kompalen-P yarn-like combined triacetate-polyamide thread

Conclusions Technological features have been studied, and manufacturing technology has been developed for Kompalen-P combined yarn-like triacetate-polyamide thread of linear density 17.3, 19.5, and 23.5 tex.It has been shown that Kompalen-P yarns can be used in fabrics as the fill and in tricotage mixed with cotton yarn, cotton-Lavsan yarn, or viscose yarn.Translated from Khimicheskie Volokna, No. 2, pp. 44–46, March–April, 1989.     

A study of the high-speed spinning process for polycaproamide complex yarns

Conclusions -- The basic laws governing the effect of spinning conditions on the properties of PCA yarns have been investigated. It has been shown that in distinction to spinning monofilaments, in high-speed spinning of complex yarns, additional factors appear by use of which it is possible to effectively control the properties of the yarns obtained.-- It has been found that the site of disposition of the aqueous lubricant in the high-speed spinning PCA yarns exerts a fundamentally different action on the breaking elongation of the yarns and on their structure, depending on the linear density and the number of elementary filaments in the complex yarn; however, it does not change the character of this dependence on the breaking strength of the yarn.-- Under otherwise equal conditions, a lower disposition of the lower lubricating device helps in obtaining complex PCA yarns which have a larger breaking strength and a lower elongation.Translated from Khimicheskie Volokna, No. 1, pp. 19–21, January–February, 1991.     

Relationship between set and bulk of package–dyed wool yarns

The loss of bulk in hand–knitting yarns as a result of package dyeing has been investigated. Simulated dyeing of packages, prepared with and without axial compression, has revealed a correlation between the bulk of the relaxed dyed yarns and the permanent longitudinal set imparted to the yarns. The strain in the yarn in the wet package, and hence the longitudinal set, is related to the hygral expansion of the yarn and the strain imposed on the yarn during winding of the package. The role of axial compression of the package in determining loss of bulk is also considered. Finally it is shown that by adding reagents to the dyebath that inhibit the setting reaction, the loss of bulk can be markedly decreased, provided also that the yarns are fully relaxed after being dyed.     

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.     

Some features of mass-exchange processes in processing single complex viscose yarns

Conclusions Processes of mass-exchange in the inner and outer regions of single complex viscose yarns during their treatment have been examined.It has been shown that in complex yarns under tension, the rate of mass-exchange and of mass-transfer is reduced with increase in yarn tension and in the number of elementary filaments.Translated from Khimicheskie Volokna, No. 2, pp. 46–48, March–April, 1985.     

Effect of geometric characteristics of a specimen on the mechanical properties of polyaramide fibres

Conclusions -- The features of the deformation behavior of complex yarns from polyaramide fibres with different geometrical characteristics have been examined.-- It has been shown that the composition of the complex yarn essentially does not affect its deformation-strength or relaxation properties.-- The effect of specimen characteristics on the intensity of stress relaxation in a yarn has been determined.NII Plastmass, Moscow. Translated from Khimicheskie Volokna, No. 5, pp. 41–43, September–October, 1992.     

Properties of acetate yarns having an increased content of elementary filaments

Conclusions A process has been developed for preparing 11/32 and 16.6/38 tex complex acetate yarns. Thereupon the yarn strength is increased by a factor of 1.2, and the resistance to repeated bending by a factor of 1.2–1.4.Processing acetate yarns having an increased content of elementary filaments in the complex yarn in textile industry plants has given good results.Translated from Khimicheskie Volokna, No. 4, pp. 27–28, August–July, 1989.     

Laws governing the stretching of preliminarily oriented polyacrylonitrile yarn

Conclusions Boundaries for the transition of polyacrylonitrile into the glassy state have been determined in coordinates of temperature vs velocity of yarn movement through heater.An analysis is given of the physico-mechanical properties of yarns which have been drawn to various extents under conditions which differ considerably from the point of view of the relaxation behavior of the material.It has been shown that the properties of yarns having various degrees of stretch are close under conditions which correspond to a single isopiest. The maximum stretch ratio under conditions which correspond to a single isopiest increase as the temperature and rate of yarn movement are reduced.Translated from Khimicheskie Volokna, No. 4, pp. 24–26, July–August, 1988.     

A multispectral imaging approach to colour measurement and colour matching of single yarns without winding

This paper investigates a multispectral imaging approach to colour measurement and colour matching of single yarns. The small size of a single yarn makes it impossible for spectrophotometers directly to acquire its spectral reflectance. Multispectral imaging systems, on the other hand, have the potential to measure the reflectance of single yarns as they can record both the spectral and the spatial information of a sample. A multispectral imaging system, namely imaging colour measurement, has been developed to conduct colour measurement of single yarns. A single yarn is first detected from backgrounds by a modified K‐means clustering method. The reflectance of the single yarn is then specified by an averaging method. Comparative experiments based on 100 pairs of single yarns and corresponding yarn windings show that the reflectance magnitude of a single yarn acquired by imaging colour measurement is smaller than that of corresponding yarn winding measured by a Datacolor 650 spectrophotometer. Experiments on 16 single yarns show that the repeatability and spatial reproducibility of the imaging colour measurement system in measuring a single yarn colour are 0.1185 and 0.2827 CMC(2:1) units. A colour matching comparison experiment (pass or fail), using 24 pairs of single yarns and corresponding pairs of solid‐colour yarn dyed fabrics, shows that single yarns measured by imaging colour measurement can achieve similar colour matching results to solid‐colour yarn dyed fabrics measured by the Datacolor 650 spectrophotometer, with degrees of similarity of 87.5 and 83.3% when the CMC(2:1) and CIE2000(2:1:1) colour difference formulas are employed.     

Advisability of establishing norms for the specific electrical resistance of viscose textile yarns

Conclusions It has been shown that the form of preparation and the amount of it on viscose yarn do not exert an important effect on its specific surface electrical resistance.The specific surface electrical resistance of viscose yarns is considerably below the limiting level of electrical resistance value which ensures normal processing of textile yarns.Translated from Khimicheskie Volokna, No. 2, pp. 39–40, March–April, 1986.     

Evaluation of the character of strength distribution of elementary filaments by testing a complex yarn

Conclusions In the case of yarn based on an aromatic polyamide, it has been shown that the strength distribution of the elementary filaments in the complex yarn can be equally well described by the normal distribution laws or by a Weibull distribution.For the Weibull distribution, an analytical expression has been found which connects the strength variation coefficients of the complex yarn and of the elementary filaments.A method is suggested for evaluating the deviation in behavior of real complex yarns from that of bundle model, which consists in estimating the critical length of an elementary filament in the complex yarn. The method permits using the indicated model in practice.Translated from Khimicheskie Volokna, No. 4, pp. 38–39, July–August, 1985.     

Investigation of some specific properties of bulk-looped yarns by the acoustical method

Conclusions The principles for change in certain acoustical characteristics of bulk-looped yarns as a function of the load straightening out the yarn have been demonstrated.It has been found that the core yarn is the channel for propagation of ultrasonic waves.The rate of ultrasound damping can characterize certain specific properties of bulk-looped yarns and thereby help optimize the technological process for preparing them.Translated from Khimicheskie Volokna, No. 1, pp. 33–34, January–February, 1986.     

Developments in Package Dyeing

Progress in package-dyeing yarn during the past ten years has been rapid, both in the total weight of yarn dyed, the types of fibre being dyed, and particularly in the design of dyeing machines and to a lesser extent in dyeing techniques. Polyester filament yarn is of great importance, but there have been significant developments in dyeing high-bulk acrylic yarns. In machinery developments, the outstanding features are in the rate of flow of liquor, and the frequency with which the liquor is circulated. New techniques have been developed to take advantage of these mechanical features, so that dyeing can be commenced at 135°C and the liquor dropped at this temperature, thus minimizing oligomer problems with polyester yarn. Many new disperse dyes of high sublimination fastness on polyester fibre have been introduced and these take full advantage of the new machinery and dyeing techniques. Another factor leading to wider use of package dyeing has been the need for shorter manufacturing cycles in the production of coloured yarn, particularly for woven fabrics. Worsted yarn, which would normally have been spun from dyed top is now being package dyed on a large scale. With spun yarns, the advantages of dyeing acrylic yarn in muff form have led to the rapid growth of this method of dyeing.     

Expenditure of heat energy in drying viscose textile yarns

Conclusions It has been found that the thermogravimetric analysis method is applicable for determining the expenditure of thermal energy in desorbing moisture from hydrocellulose textile fibres; it gives a quantitative evaluation of the fractional composition of the water sorbed by the yarns and of its bonding energy with the yarn matrix.The change in consumption of heat energy at various extents of drying of freshly-spun viscose textile yarns has been studied.It has been found that extensive drying of yarns, to a moisture content significantly lower than the conditioned values, that is, overdrying, requires elevated, unjustified expenditures of heat energy.Translated from Khimicheskie Volokna, No. 4, pp. 43–44, July–August, 1987.     

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.