Effect of Filament Fineness on Composite Yarn Residual Torque

Yarn residual torque or twist liveliness occurs when the twist is imparted to spin the fibers during yarn formation. It causes yarn snarling, which is an undesirable property and can lead the problems for further processes such as weaving and knitting. It affects the spirality of knitted fabrics and skewness of woven fabrics. Generally, yarn residual torque depends on yarn twist, yarn linear density, and fiber properties used. Composite yarns are widely produced to exploit two yarns with different properties such on optimum way at the same time and these yarns can be produced by wrapping sheath fibers around filament core fiber with a certain twist. In this study, the effect of filament fineness used as core component of composite yarn on residual torque was analyzed. Thus, the false twist textured polyester filament yarns with different filament fineness were used to produce composite yarns with different yarn count. The variance analysis was performed to determine the significance of twist liveliness of filament yarns and yarn count on yarn twist liveliness. Results showed that there is a statistically significant differences at significance level of α=0.05 between filament fineness and yarn residual torque of composite yarns.

Effect of Cellulase Enzyme on the Mechanical and Surface Properties of Regular and Compact Yarns

The degrading property of cellulose by the enzyme is utilized in improving the surface properties by removing the protruding fibers from the surface of the yarn. In this work, the regular and compact yarns made out of same mixing at various stages of chemical processing were treated with cellulase enzyme with different levels of concentration and temperature. Measurement of the weight loss, bending rigidity, wicking rate, work of rupture, shrinkage loss, tenacity and elongation of the yarn were studied for the two different yarns. Bending rigidity and wicking rates were found to decrease and increase respectively in normal yarns compared to compact yarns. All the above trends therefore suggest that the compact yarns are not much affected by the concentration of the enzyme compared to the regular yarns. As the concentration of the enzyme was increased, the weight loss, bending rigidity, shrinkage loss, twist liveliness, tenacity, work of rupture, elongation and wicking rate were also found to vary irrespective of the spinning system.

Mathematical formulation of knitted fabric spirality using genetic programming

This paper proposes the use of genetic programming for the mathematical formulation of knitted fabric spirality. Both dry relaxed and wash-and-dry relaxed states of fabric spirality are studied. In total, six parameters are investigated, in which three parameters are derived from yarn and fabric, and the other three parameters are from the knitted condition. The three yarn and fabric parameters used are yarn twist liveliness, tightness factor and dyeing method, and the three knitting parameters are the number of feeders, rotational direction and gauge. Genetic programming is adopted to formulize the mathematical relationships between above the six parameters and two states of fabric spirality, respectively. For a comparison, a multiple linear regression approach is studied as well. The formulas generated by genetic programming and multiple regression for two states of spirality are comprehensively investigated and compared. Experimental results show that genetic programming, which can model non-linear mathematical relationships, obtains more accurate expressions than multiple regression for both dry relaxed and wash-and-dry relaxed states of spirality, demonstrating that genetic programming is a promising alternative for the mathematical formulation of fabric spirality.

Torque-Balanced Singles Knitting Yarns Spun by Unconventional Systems Part II: Cotton Friction Spun DREF III Yarn

This paper is concerned with the application of a modification process to cotton friction spun singles yarns. The experimental results show that the yarn modification process can effectively reduce or eliminate residual torque in dref-III singles yarns as well as fabric spirality in plain knitted structures. The properties and performance characteristics of yarns and fabrics are evaluated, including hairiness, diameter, evenness, tensile properties, and twist liveliness of the yarns, and thickness, weight, air permeability, thermal conductivity, bursting strength, and pilling resistance of the fabrics. The effects of yarn production parameters, relaxation, and modification processes are also discussed.

Geometry and Dimensional Properties of Plain Loops Made of Rotor Spun Cotton Yarns

The spirality of wale lines is shown to affect shape factor and hence fabric dimensions. Spirality is determined by yarn twist liveliness, tightness factor, and machine gauge, whereas yarn twist liveliness is governed by actual yarn twist. Full relaxation may decrease or increase spirality depending on whether the tightness factor of the parent fabric is greater or less than 14.0. To minimize spirality in the finished fabric, the cloth should be knitted on a machine with the finest possible gauge at a tightness factor value ≥ 14.0.