Twist-controllable sheath-core countertwist yarns with enhanced softness and robust mechanical properties in the ring spinning system

Purpose Yarns that offer desirable softness and low residual torque, while maintaining adequate strength, are highly sought after for enhancing comfort and meeting processing requirements in textiles. By structure design and modified spinning processes, we aimed to develop a novel countertwist ring-spun method to produce all-staple, sheath-core structural yarns with both optimized softness and adequate strength. Design/methodology/approach A two-step twisting approach was used to apply counter twisted sheath-core structure to the designed ring-spun yarns. The morphological analysis reveals the twist transition between the core yarn and the outer sheath fibers during the spinning process. The effect of the applied twist factor on the softness, strength, residual torque, hairiness and abrasion resistance performance of the sheath-core countertwist yarn was systematically investigated. A comprehensive comparison between the developed countertwist yarns with conventional ring-spun yarns was also conducted. Findings Results show that the sheath-core countertwist yarn possesses minimal loss in breaking strength (<9.2%) and a slight increase in hairiness (<2.4%) compared to conventional ring-spun yarns, while achieving a remarkable reduction in bending stiffness (>18.9%, p < 0.001) and maintaining desirable softness. Moreover, the overall performance of the sheath-core countertwist yarn outperforms certain ring-spun yarns produced by new spinning technologies. Practical implications The developed sheath-core countertwist yarn offers a promising alternative for producing soft and comfortable textiles with low skew and robust mechanical properties, showing great potential for commercial applications, such as baby undergarments. Originality/value Currently, achieving a balanced performance in both the softness and strength of ring-spun yarns remains challenging. Moreover, soft yarns spun by low-twist methods generally suffer from low abrasion resistance and high hairiness. There is no research reporting on the structure design of sheath-core countertwist yarns and systematic studies on the effects of twisting evolution of sheath and core yarns have yet to be conducted.