Silicon-containing reactive dyes for acidic fixation on cotton and their application in one-bath one-step dyeing of polyester/cotton blends
摘要
Traditional reactive dyeing of cotton requires alkali, leading to issues such as dye hydrolysis and challenges in one-bath dyeing of polyester/cotton blends with disperse dyes. To overcome these limitations, a novel acidic cross-linking strategy was developed using silicon-containing reactive dyes and the silane coupling agent (3-aminopropyltriethoxysilane, KH550). Under weak acidic conditions (pH = 5.0), a three-dimensional “dye-cross-linker-fabric” cross-linking network was successfully constructed through reactions between silanol groups and fabric hydroxyl groups, reactions between the amino groups of KH550 and the reactive groups of the dyes, and self-condensation of silanol groups, thereby fixing the dyes onto the fabrics. This method achieved high fixation rates of 91.3%–96.4%, with excellent wash and rubbing fastness. Furthermore, by selecting matching disperse dyes, one-bath one-step dyeing of polyester/cotton was realized. The thermosol process for disperse dyes did not hinder reactive dye fixation, and KH550 even enhanced disperse dye uptake. Total dye utilization exceeded 90%, with outstanding fastness and levelness. This approach shortens the dyeing process, reduces energy use and effluent load, offering an efficient and eco-friendly alternative for blended fabric dyeing.