Cost-performance evaluation of socks developed from post-consumer denim waste and recycled polyester

Abstract Post-consumer denim waste is a major cotton-rich waste stream, but its use in durable textile products remains challenging because mechanical recycling shortens and damages fibers. This study developed half-terry socks from recycled denim cotton blended with recycled polyester and compared them with virgin polyester/cotton control socks. Twelve variants of recycled yarns were produced using three recycled polyester/recycled cotton ratios: 90/10, 80/20, and 70/30, through ring and rotor spinning at two twist levels. The socks were evaluated for structural properties, comfort-related performance, durability and production cost. The recycled socks were successfully produced with comparable structural properties to the control and generally showed higher air permeability, indicating better breathability. Moisture management was mainly controlled by sock region, following the order leg > upper foot > terry sole, with the terry sole acting mainly as an absorbent and cushioning zone. Cost analysis showed that recycled socks were cheaper, costing 0.149 to 0.152 €/pair, compared with 0.160 €/pair for the virgin control. However, durability is the main limitation: all recycled socks showed pilling grade 1, while the control showed grade 3, and abrasion loss increased with recycled cotton content. Recycled denim-based socks demonstrated comparable structural properties, improved breathability, lower estimated production cost, slightly higher air permeability, and circular material benefits; however, poor pilling resistance and greater abrasion loss remain key barriers to commercial adoption, highlighting the need for further improvements in recycled yarn quality and surface durability.