Technology progress and application prospects of liquid disperse dyes

Significance Disperse dyes are special dyes for polyester fiber dyeing, commercially available mainly in powder and liquid forms. Powdered disperse dyes are widely used because of their excellent storage and application stability, while liquid disperse dyes are restricted by their stability. In recent years, with the great demand for energy conservation and emission reduction in printing and dyeing, liquid disperse dyes have attracted much attention, because of the advantages over the powdered disperse dyes in higher utilization rate of dye, low discharge of wastewater and waste residue and low energy consumption. Although the stability of liquid disperse dyes restricts its development to a certain extent, with the progress of the preparation technology of liquid disperse dyes, the stability has been effectively improved, and has been gradually replacing the traditional powdered disperse dyes.Progress The lapping technology of liquid disperse dyes were briefly introduced. Selecting suitable anionic/ non-ionic surfactants and anti-sedimentation agents was recognized as the key factor to prepare liquid disperse dyes with excellent stability and application performance. The main processing parameters affecting the properties of liquid disperse dyes were analyzed, and the influence of theological property and ambient temperature on the stability of liquid disperse dyes were clarified. As the second attempt, the principle of high temperature dispersion, low temperature dispersion and double electric layer diffusion of liquid disperse dyes were analyzed. It was indicated that the viscosity increasing temperature (T0 value) and the absorbance change rate of water dilution (Al0) could be used as indexes to evaluate rapidly the stability of liquid dyes. Then, the energy conservation and environmental friendliness and advantages of liquid disperse dyes in high temperature and high pressure dyeing, round mesh and screen printing are analyzed, and the new applications in continuous hot melt dyeing are analyzed, and the prospect of dyeing and finishing in the same bath processing was pointed out.Conclusion and Prospect Although the preparation process of liquid disperse dyes is similar to that of powdered disperse dyes, liquid disperse dyes use less water and a small amount of additives (anionic/non-ionic mixture) as fillers. The difference in the performance of the two types of disperse dyes leads to the realization of low water consumption and near-zero emission printing and dyeing technology of liquid disperse dye, which could form a major energy conservation and emission reduction technology to meet the needs of printing and dyeing industry from the source. Liquid disperse dyes have been widely used, but their potential advantages have not been fully utilized. Therefore, the establishment of liquid disperse dye commodity standards, control of dye standardized quality, research and development of new bath dyeing and functional finishing technology are imperative to meet our 'carbon emissions and carbon neutrality' source pollution control printing and dyeing technology needs. © 2023 China Textile Engineering Society. All rights reserved.