Urea-free reactive printing of viscose fabric with high color performance for cleaner production

Urea-free reactive printing has gained popularity as part of cleaner production in the textile printing industry. Printing additives containing little to no nitrogen are being explored as substitutes for urea. In this study, the hygroscopicity, ability to swell fibers, and ability to solubilize reactive dyes of various additives were compared to explore the intrinsic connections between the structures and the above-mentioned properties. The hydrogen-bond interactions between the reactive dye and additives were characterized by 1H NMR and DSC. Additives with good hygroscopic, swelling, and solubilizing properties were selected for their potential application in urea-free reactive deep printing on viscose fabric. Results showed that among various kinds of additives, glycerol had the best hygroscopicity, 1,4-butanediol had the best ability to swell viscose fibers, and the amides had the best ability to solubilize reactive turquoise K-GL. Hygroscopicity was considered as the most important factor, followed by the ability to swell fibers. When the mixed ratio of glycerol and 1,4-butanediol was 5:5, the color performances of the binary nitrogen-free compound were higher than those of a commercial alternative. Its printing performances came close to those of urea, exhibiting great potential as a substitute for urea. Nitrogen-free alternatives will remarkably reduce the ammonia–nitrogen pollutants emitted into the environment by the reactive printing process.