High-fiber utilization, low-hairiness composite structural yarns based on novel spreading–feeding strategy

To address the critical challenge of simultaneously achieving low hairiness and high strength in composite yarns with high fiber utilization, this study pioneered the integration of fiber-spreading and external-feeding devices onto a ring spinning frame. Firstly, by precisely controlling cotton short fiber contents (7.73%, 8.40%, 14.75%) and filament feeding paths, three composite yarn structures were engineered: a traditional polyester/cotton composite structural yarn (T-CSY); an internally fed filament spreading composite structural yarn (IFS-CSY), in which spread filaments form a web structure enhancing fiber-filament friction; and an externally fed filament spreading composite yarn (EFS-CSY), featuring spread filaments encapsulating short fibers to optimize surface coverage. Then, the properties of the composite yarns prepared with different structures were tested. Results demonstrate that, at 8.40% cotton short fiber content, the IFS-CSY had significantly enhanced tensile properties, exhibiting 2% and 20% higher strength than T-CSY and EFS-CSY, respectively, and elongation at break improvements of 32.81% and 46%. Conversely, EFS-CSY effectively encapsulated fiber ends through continuous outer wrapping, reducing total hairiness by 89.25% and 63.49% versus T-CSY and IFS-CSY while improving yarn evenness. This breakthrough in the encapsulation mechanism successfully overcomes the long-standing trade-off between surface quality (hairiness control) and mechanical robustness in high-utilization composite yarns, leading to substantially upgraded overall performance.