Salt-Free and Alkali-Free Fixing Method of Wool Fabric Dyeing in Non-Aqueous Media Dyeing System

Non-aqueous media dyeing is an important water-saving and salt-free dyeing technology in the textile dyeing industry. In this investigation, a salt-free and alkaline-free dyeing technology was developed for wool fabrics. After padding with reactive dye solution, wool fabric was fixed in a non-aqueous medium at 90 °C for 90 s. After washing, the fixation of reactive dye can achieve more than 98% in a salt-free and alkali-free dyeing environment. The effect of fixing method on the physical properties of wool fabrics was analyzed by TGA, DSC, and XRD. Compared with steam and cold batch fixing method, the fixing process in non-aqueous medium has little effect on the mechanical properties of wool fabrics. The final decomposition temperature of wool fabric dyed with non-aqueous medium was about 46 °C, which was higher than that of the fabric samples dyed by other methods. Moreover, the crystallinity of wool fiber was increased after non-aqueous fixation process. And non-aqueous medium had no influence on the surface morphology of wool fabrics. For non-aqueous medium and steaming fixing methods, there were only hydrolyzed dyes, but some hetero-bifunctional dyes were detected in the cold batching system, indicating that reactive dyes could effectively react with wool fibers in non-aqueous medium and steaming fixing system.