Urea for Advantages and Disadvantages of Disperse/Reactive Dyes

Urea has a certain effect on the amount of color and vividness of reactive dyes, and the fixation of disperse dyes on polyester. Moreover, it also has a significant effect on preventing yellowing of cotton fibers due to alkali agents at high temperatures. However, it melts, evaporates, and decomposes at a high temperature of 131°C. It forms a co-melt with disperse dyes and promotes the diffusion of disperse dyes into cotton fibers, resulting in severe contamination. It can also promote the contamination of polyester with terpenes by reactive dyes, so that the staining of the two fibers will reduce the vividness after printing and also affect the fastness. Therefore, adding urea to the color paste has both advantages and disadvantages, and it is necessary to select a reasonable amount.

Reprinted from: China Printing and Dyeing Network