An eco-friendly, water-saving and cost-effective approach to manufacturing machine-washable wool fabric using a broad-temperature-range proteinase (BTRP) and an innovative "pad-steam-pad-cold batch" technique

Nowadays, the Chlorination-Hercosett process dominates the production of machine-washable wool fabric. However, absorbable organic halogens (AOX) generated during the treatment are highly detrimental to human health and the environment. Herein, we developed an innovative pad-steam-pad-cold batch enzymatic treatment with the merit of being eco-friendly, water-saving, and cost-effective to replace traditional high pollution chlorination technique. With the assistance of sodium sulfite or L-cysteine, a broad-temperature-range proteinase (BTRP) can efficiently hydrolyze wool scales during the steaming and cold batch processes. The results indicate that BTRP treatment endows the wool fabric with excellent dimensional stability, acceptable strength loss, and improved wearability properties such as drapability, and air and moisture permeability. This non-chlorination treatment achieves a felting shrinkage of 4.33 % ± 0.28 %, and a tensile strength loss of 12.36 % ± 1.46 %. Furthermore, colored wool samples treated with BTRP were shown to maintain their original color performance, including K/S value and various color fastness properties. Pilot plant tests indicates that this technique remarkably decreased the cost of chemical materials and water usage during enzymatic treatment. As an ideal alternative substitute for the Chlorination-Hercosett treatment, the "pad-steam-pad-cold batch" approach based on BTRP treatment can be utilized for commercial production of pristine and colored machine-washable wool garments.