Acid dye refers to the acid group contained in the dye molecule, also known as anionic dye, which can combine with the amino group in the protein fiber molecule by ionic bond, and is applicable under acidic, weak acid or neutral conditions. Mainly are azo and anthraquinone structures, and a few are aromatic methane structures. Dyes and colors are generally compounds that have their own colors and can make other substances obtain bright and firm colors in a molecular or dispersed state.
Acid dyes are classified into strong acid, weak acid, acid media, acid complex dyes, etc. according to their chemical structure and dyeing conditions.
Acid dyes have complete chromatograms, bright colors, and light fastness and wet processing fastness vary greatly depending on the type of dye. Compared with direct dyes, acid dyes have a simple structure, lacking long conjugated double bonds and coplanar structures, so they lack directness to cellulose fibers and cannot be used for dyeing cellulose fibers. Different types of acid dyes have different dyeing properties and different dyeing methods due to different molecular structures.
Mainly used for dyeing wool, silk and nylon.