Effects of draw ratio and elastic core yarn positioning on physical properties of elastic wool/polyester core-spun ring yarns

Abstract

In this article, the draw ratio of elastic core yarn (Spandex filament 44 dtex/f4) was regulated from 2.7 to 4.41 (i.e., 2.7, 3.22, 3.49, and 4.41) by using a developed positive feed drive and a microcontroller system. The elastic core positioning (left, center, and right) in front roller nip of ring frame was also changed using a standard V-groove guide roller. The physical properties of produced yarns including tensile properties, hairiness, irregularity, and fibre covering were investigated and compared. The results revealed that at 3.49 draw ratio, themaximum elastic core-spun yarn tenacity and elongation and minimum S3 hairiness values were obtained compared with 2.7 and 4.41 draw ratios. The results indicated that increasing the elastic yarn draw ratio increased the elastic core-spun yarn irregularity and fibre-covering factor by which the highest values were obtained at 4.41 elastic yarn draw ratio. It was also found that elastic yarn positioning at the left edge of roving ribbon deteriorated core-spun yarn evenness while elastic yarn positioning at the center of the roving ribbon improved the core-spun yarn hairiness. However, elastic yarn positioning has no significant effect on elastic core-spun yarn tensile and fibre-covering properties.