Classification of acid dyes

Classification of acid dyes

 Acid dyes are classified into strong acid, weak acid, acid media, acid complex dyes, etc. according to their chemical structure and dyeing conditions. 

1) Strong acid dyes The earliest developed acid dye requires dyeing in a strong acid dye bath. It has a simple molecular structure, low molecular weight, contains sulfonic acid or carboxyl groups, has little affinity for wool, and can move evenly on wool. It is evenly dyed, so it is also called acid level dyeing dye, but the shade is not deep, the washing fastness is poor, and the wool is damaged during dyeing, and the dyed wool feels poor. Such as Acid Red G.

 2) Weak acid dyes In strong acid dyes, weak acid dyes are formed by increasing the molecular weight, introducing groups such as arylsulfone groups, or introducing long carbon chains. The molecular structure is more complex, and it has a greater affinity for wool. It can dye wool in a weak acid medium without damage to the wool. The shade is darker and the fastness is improved, but the dyeing is uneven. Such as weak acid brilliant blue RAW (ie C.I. Acid Blue 80). 

3) Acid mordant dye After treated with certain metal salts (such as chromium salts, copper salts, etc.) as mordants, acid dyes that form metal complexes on the fabric. Mordant dyeing procedures are more complicated, but dyes with better properties such as light fastness, washing fastness, and rubbing fastness can be obtained, such as acid mordant black T (ie C.I. mordant black 11).

 4) Acid complex dyes It is formed by complexing some acid dyes with metals such as chromium and cobalt. It is soluble in water, and its dyed products have excellent light fastness and light fastness. Its dye matrix is similar to acid mordant dyes, but in the preparation of dyes, metal atoms have been introduced into azo dye molecules, and the ratio of metal atoms to dye molecules is 1:1, so it is also called 1:1 metal complex dye. There is no need to use mordant for dyeing. Such as acid complex yellow GR (ie C.I. Acid Yellow 99).