Enhancing fibre-to-fibre recycling of mechanically recycled cotton through combed compact ring spinning

Growing pressure from consumption-driven textile waste, the fashion industry, EU regulations, and global sustainability frameworks have intensified the need for effective fibre-to-fibre recycling routes capable of retaining material value. While mechanically recycled cotton is widely applied in rotor spinning, its integration into ring and compact spinning systems remains limited due to high proportion short-fibre content and the associated challenges in maintaining stable draftability. This study presents industrial-scale process trials designed to evaluate mechanically recycled cotton behaviour across different fibre preparation routes, with a particular focus on combing performance and its influence on recycled fibre blend selection and waste extraction. Mechanically recycled cotton was blended with virgin cotton and processed through carded, double-carded and combed routes under varying combing settings. The results demonstrate that combing and compact spinning play a critical role in managing the high short fibre content of mechanically recycled cotton by stabilising fibre distribution and improving yarn mechanical performance and imperfection values at increasing mechanically recycled cotton ratios. High-quality ring-spun yarns were achievable even at 50% mechanically recycled cotton when optimised combing conditions were applied. Moreover, 50% rCO combed yarns exhibited approximately 50% lower nep and thick place compared to 25% rCO carded yarns. By enabling higher recycled fibre contents in value-added yarn applications, these findings contribute to the expansion of fibre-to-fibre recycling pathways and support waste valorisation strategies within circular textile production systems.