A relative hairiness index for evaluating the securities of fiber ends in staple yarns and its application

Hairiness is a prominent property of staple yarns, but the existing evaluation parameters mainly describe the fiber ends already protruding out of yarn bodies. The potential fiber ends in yarns also play a crucial role in the performance of yarns in the subsequent processes and the resultant fabric quality. In our previous studies, maximum hairiness and its theoretical model have been proposed, which indicate the maximum fiber ends of a staple yarn having the potential to protrude out of yarn bodies and become hairy. On this basis, the relative hairiness index (RHI) is developed in this study to evaluate the fiber end tucking and securities of yarns. This index is treated as a ratio of the measured hairiness of sample yarns and the maximum hairiness of ring yarns in the same twist level and yarn count. A lower RHI indicates more fiber ends being tucked into yarn bodies, and a slower increment of the RHI with the increasing winding times represents more stable securities of fiber ends in yarns. The experimental results demonstrate that the RHI can directly reveal the effectiveness of different spinning parameters and methods in tucking and securing fiber ends; also, the changes of the RHI with increasing winding times visually present the stableness of fiber ends in various yarns experiencing abrasion, as well as predict the possibility of the potential fiber ends being pulled out to form hairiness during successive processes. The proposed RHI, therefore, provides a significant reference for the spinning process design and yarn quality control.