Acid dyes

Acid dyes can be categorized by considering their basic chemical structure and they are mostly derivatives of following,

·         Derivatives of tri-phenyl methane - Group 1

·         Derivatives of xanthenes - Group 2

·         Nitro dyes - Group 3

·         Some Acid dyes Azo Groups - Group 4

·         Pyrazolone Azo Dyes - Group 5

·         Dyes derived from anthraquinone - Group 6

·         Phthalocyanine  dyes - Group 7

But according to the application of that acid dyes can be classified into three classes and they are,

Class 1- Dyeing with strong acids (eg: Tartrazine, Solwey Blue BN, Azo Geranine 2G)

Class 2 - Dyeing with weakly acid liquor (eg: Xylene Fast Red P, Erio Fast Blue)

Class 3 - Dyeing with neutral liquor (eg: Acid Milling Red G, Coomassie categories)