Worldwide yarn diversity in terms of structure and properties has increased in recent years. Especially composite yarns produced by multiple components have become very preferable in both weaving and knitting sectors. Among these yarns, core and dual core-spun yarn are more prominent in some areas due to their particular performance. In this study, the structure and properties of plain, elastane cored, and elastane + filament cored composite yarns, which were spun by using cotton as sheath fibers, are comparatively investigated. With a constant Ne 16/1 linear density, a carded yarn production line with modified ring-spinning system was used to produce the composite samples using 5.56% elastane ratio for both and 13.79% polybutylene terephthalate (PBT) ratio for dual core. It was observed that the strength of the composite yarns decreased, while the elongation values at the time of breaking tended to increase. There was some deterioration in transition from plain yarn to dual core composite yarn in terms of unevenness and yarn defects, while some improvement was observed in terms of yarn hairiness. In order to dwell on the causes of this situation, the surface and cross-sectional images of the yarns were also studied.

Elastic structures are opted in denim fabrics to increase elasticity and recovery properties of fabrics as well as comfort properties. In this study, performance properties of denim fabrics were evaluated comparatively as tensile strength, tearing strength, air permeability, mass change, dimensional stability, seam slippage, fabric growth, and stretchability. 100% cotton, core-spun and dual-core spun yarns (Ne 16/1) used at weft direction of denim fabrics. 100% cotton ring spun yarns (Ne 13.5/1) were used as warp yarns at all produced three denim fabrics. All the test results were measured numerically and evaluated statistically with one-way analysis of variance (ANOVA). There was significant difference found among fabrics for the variation of weft yarn structures from the statistical evaluation. The impact of varying washing processes on the stretch and growth (%) of denim fabrics was also revealed. Core-spun yarn containing denim fabric showed more growth and stretch percentage in all forms of washing processes. It was also found that packing density of yarns had a significant effect on air permeability of fabrics.

The spinning industry makes a major contribution to environmental pollution due to the excessive use of natural assets and the generation of remarkable amounts of waste during manufacturing processes. Now, the spinning industries are concentrating on sustainable activities due to environmental issues. While textile recycling efforts have been widely explored, the utilization of soft waste (process waste) in yarn production remains underexplored. This study addresses this gap by investigating a sustainable approach incorporating soft waste into producing sustainable yarn using the ring-spinning technique. The research explores the properties of yarns manufactured from a blend of virgin cotton and soft waste, and 100% virgin cotton yarn is produced for comparison. The results indicate that incorporating soft waste leads to an increase in CVm% (13 vs. 11), hairiness (6.9 vs. 5.1), and IPI (165 vs. 125) compared to virgin cotton yarn. However, the elongation percentage (7.1% vs. 8%) and tensile strength (12.6 cN/tex vs. 16.2 cN/tex) showed a reduction, highlighting potential trade-offs in mechanical properties. The statistical analysis applies one-way ANOVA to evaluate the significance of variations in yarn characteristics made from the mixture of soft waste + virgin cotton and only virgin cotton. The manufactured yarns were examined in a modern weaving machine as weft yarn for fabric (denim) manufacturing and found to be perfect for normal operation. The article focuses on reducing negative impacts on the fabric (denim) manufacturing environment by incorporating soft waste to produce sustainable yarn. This research provides important insights into the production of sustainable yarns, focusing on environmental concerns.

Consumer choice and behavior are changing and focusing on comfortable clothing along with fitting. Elastic yarn or fabric is necessary to achieve this comfortableness. By making elastic yarn and using elastic material in fabric production, elastic cloths are produced with proper stretchability and recovery. For that, core-spun yarn was used, but due to a lack of recovery performance, dual core-spun yarn has been developed. Different elastane ratios, linear density, and filaments were used in the dual core-spun yarn according to achieve desired stretchability. In this study, denim fabric performances were evaluated by designing different composite/hybrid dual core-spun yarn with a combination of cotton fiber and filaments. Different elastane linear densities with different filaments, PET/PTT, PTT, and PET, were used, and it was found that using finer elastane in dual core-spun yarn, strength, and unevenness are increased, and elongation decreased. Using PET/PTT filament increases hairiness, and using PTT filament increases elongation. For fabrics, coarser elastane in the dual core-spun yarns has higher stiffness, elasticity, and shrinkage. Fabric with PTT showed higher weight change and stiffness, whereas PET filament-based fabric samples have good strength and low stiffness. In addition, a multiple regression analysis was carried out for yarn and fabric properties, and mathematical models were developed.

Elastic core-spun yarns which is used as weft yarn for textile fabrics gained great importance in the last decade its due to the fact that stretch and recovery, comfort fits and flexibility properties. The technological progress made the dual core-spun yarn production possible. The dual core-spun yarns are composed of filament that contributes durability and polyurethane based elastane that provides stretchability to the fabrics. Hereby, both filament and elastane characteristics have great influence on denim performance at the same time. The main purpose of this study is to achieve the effect of filament fineness and elastane draft on denim fabric performance such as breaking force, breaking elongation, tear force, vertical elastic recovery, moisture management that is wicking rate and water absorption properties. Meanwhile, filament core-spun yarns with different filament fineness and 100% cotton yarn were also used as weft of the denims in order to investigate the differences statistically. It was found that that filament fineness and elastane draft had statistically significant effect on all inspected performances of denim fabrics except water absorption.