What are the choices of dyeing auxiliaries for nylon and spandex blended or interwoven fabrics?

The commonly used dyes for nylon are acid and neutral dyes, these dyes can also dye spandex, but the fastness is poor, especially the acid dye fastness is worse. Therefore, the fastness of dyed blended fabrics with these dyes is always worse than that of pure nylon fabrics.

For this purpose, dyes with good fastness should be selected, such as Lanaset dyes from Ciba Company, and some domestic neutral dyes are also available. In addition, the levelness of these dyes is poor, so it is very important to formulate a reasonable dyeing process, especially controlling the pH value of the dye bath and washing and fixing after dyeing. And because nylon absorbs acid dyes quickly, a retarder should be used for this purpose, and the starting temperature of dyeing should also be lower, so that the two fibers have a better effect of the same color. If it is unmodified spandex, the spandex is light in color under normal conditions, and the wet fastness is very low, so other dyes or dyeing methods need to be used for dyeing.