Excellent fixation of low-water-soluble reactive dyes containing vinylsulfone group for nylon dyeing

A significant amount of wastewater is generated in printing and dyeing processes of nylon textiles. The wastewater pollutes the environment and increases the post-treatment costs. To simultaneously obtain the excellent dye utilization and color fastness, low-water-soluble reactive dyes (LWSRDs) with vinylsulfone group as a reactive group were developed in this paper. The LWSRDs have dual characteristics of high exhaustion and forming covalent bonds with nylon fibers in neutral conditions. These characteristics result in higher fixation on nylon 6 traditional fibers (NTF) using Traditional dyeing process (TDP) compared with commercial reactive dyes. Based on the characteristics of LWSRDs, modified dyeing process (MDP), which was conducted in one-pot, significantly reduces the costs of chemicals and wastewater. Moreover, the fixation of LWSRDs on nylon fibers using MDP was higher than that using TDP. Notably, the dyed nylon fibers were uniform and vibrant, and demonstrated exceptional color fastness against washing and rubbing, exceeding grade 4. The results of innovative LWSRDs and their corresponding MDP offer an effective approach to dyeing nylon fibers, with good application prospects in dyeing industry.