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.     

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.     

Change in properties of polycaproamide textile yarns on water-stabilization treatment

Conclusions The kinetics of washout of low-molecular-weight fractions from polycaproamide textile yarns during water-stabilization treatments has been studied. It has been found that the supermolecular structure of the yarns is considerably changed thereupon; the degree of crystallinity is increased, the size of the amorphous regions is reduced, the yarn porosity is increased, thereby increasing the rate of dye sorption, the yarn stress is reduced, and its shrinkage is lowered.The increase in yarn porosity as a result of water-extraction and stabilization treatment ensures raising their sorptive power with respect to dyes and various low-molecular-weight modifiers.Translated from Khimicheskie Volokna, No. 4, pp. 42–44, July–August, 1984.     

A continuous technological line for the extraction and drying of NéS-KS-5 polycaproamide

Conclusions The quality of PCA granulate obtained on the continuous line of the NÉS-KS-5 machine (man-made yarn combine, Vidin, Bulgaria) has been analyzed.Experimental specimens of the yarns prepared from this granulate have better processibility in the textile treatment process, which makes it possible to reduce the amount of technological waste by a factor of 2.6.Bulgaria. Translated from Khimicheskie Volokna, No. 1, pp. 41–42, January–February, 1984.     

Some features of pilling formation on carpeting from synthetic texturized new types of yarns

Conclusions It has been found that pilling formation does not take place on carpet items made from pneumotexturized polyamide or matrix-fibrillar yarns.On prolonged abrasion of carpet specimens from yarns of the matrix-fibril type, fibrillation of the yarns is observed, accompanied by an increase in the surface density of the carpet pile mass.Translated from Khimicheskie Volokna, No. 5, pp. 35–36, September–October, 1985.     

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.     

Modified polypropylene yarns from oriented film for manufacture of goods for national consumption and technical articles

Conclusions A technological process has been developed for preparing modified film yarns from a mixture of polypropylene and low density polyethylene having a content of the latter up to 10% by wt.; these yarns are used to make goods for national consumption or technical articles, with an economic advantage of 50 rubles per metric ton of yarn.When small additions of LDPE are introduced into polypropylene, an increase in the degree of yarn stretch is observed.The suggestion has been made that small additions of LDPE heal defects in the structure of oriented polypropylene, which is prone to spontaneous fibrillation; this aids in obtaining yarns with increased strength, elasticity, and lower tendency to split.Translated from Khimicheskie Volokna, No. 1, pp. 45–47, January–February, 1989.     

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.     

Increasing the dyeing uniformity of viscose textile yarn

Conclusions The possibility of significantly raising the dyeing uniformity of viscose textile yarn by activating the cellulose and by selecting technological spinning parameters which ensure maximum yarn shrinkage before its arrival at the centrifuge has been shown.It has been found that, with increase in the ability of the freshly spun yarn to shrink, its dyeing uniformity is reduced.The dyeing uniformity of viscose yarn prepared by the centrifugal method can be raised by changing its shrinkage on the spinning machine during the spinning process, by activation of the cellulose, and by choosing a precipitation bath which is very suitable for spinning viscose yarns from activated celluloses.Translated from Khimicheskie Volokna, No. 2, pp. 41–42, March–April, 1984.     

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.     

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.     

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.     

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.     

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.     

Properties of Textured Yarns of Low Linear Density by Commercial Package Layers

The effect of the structure of commercial packages on the properties of textured yarn of low linear density is investigated. The possibility of using commercial packages with textured yarns of low linear density weighing 2.5 kg for 1.67 tex yarn, 3 kg for 2.2 tex yarn, and 4 kg for 3.3 tex yarn is established.__________Translated from Khimicheskie Volokna, No. 1, pp. 42–45, January–February, 2005.     

Increasing the wear-resistance of yarn-guide bend elements in liquid treatment of yarns

Conclusions The frictional force of yarns on yarn-guide bends in spinning and washing essentially does not depend on the linear density of the yarn or its rate of movement within the range 60–300 m/min.The frictional force of yarns on rings of artificial corundum is less than on rings of metal, Pyroceram, or glass.Special constructions of the elements of yarn-guid bends, which make it possible to reduce the length of contact of the yarn with the friction body, considerably reduce frictional force and, consequently, the yarn tension in the system.Translated from Khimicheskie Volokna, No. 3, pp. 43–44, May–June, 1986.     

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.     

Rheological properties of polyamide 54-polyethylene mixtures

Conclusions Monofilaments have been prepared from polyamide 54-polyethylene mixtures which have a matrix-fibrillar structure.A correlation has been observed between the flow index and the degree of expansion of a jet of PA54-PE mixture melts when there is from 0 to 50% PE in the mixture of from 60 to 100% PE. In the region of phase inversion, the correlation between these figures breaks down.The complex multifactor nature of the extreme-type increase in the degree of expansion of jets of PA54-PE mixture melts has been confirmed experimentally.It is suggested that the impairment in spinnability of PA54-PE mixtures on introduction of up to 30% PE is connected with a increase in the flow index and degree of jet expansion.DeceasedTranslated from Khimicheskie Volokna, No. 5, pp. 14–16, September–October, 1984.     

Technological principles in texturizing polycaproamide yarns

Conclusions Texturization of yarns by the press-chamber method leads to the formation of twists of the flat zig-zag type on smooth yarns. Because of the receipt of crimp, a yarn is obtained with an increased bulk and improved heat-insulating, and hygienic properties.After texturizing, appreciable changes take place in the structure and morphology of elementary filaments. The latter causes a change in the complex of physicomechanical yarn properties.By the use of basic technological texturizing parameters, it is possible to vary the characteristics of the basic specific properties of crimped yarns.Translated from Khimicheskie Volokna, No. 2, pp. 27–34, March–April, 1985.     

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.