What is an acid dye？

Acid dye refers to the dye molecules containing acid groups, also known as anionic dyes, and protein fiber molecules in the amino group to ionic bond, in acid, weak acid or neutral conditions. Mainly azo and anthraquinone structure, a few aromatic methane structure. Dye and color are generally their own color, and can be in a molecular or dispersed state to give other substances a bright and firm color compounds.

Acid dyes have complete chromatograms and bright colors. Their fastness to sun and wet treatment varies greatly with different dyes. Compared with direct dyes, acidic dyes have simple structure, lack of long common double bonds and homoplanar structure, so they lack directness to cellulose fibers and cannot be used for dyeing cellulose fibers. Different types of acid dyes, due to different molecular structure, so their dyeing properties are different, the dyeing method is also different.