1, the history of acid dyes:
In 1868, the earliest acid dye appeared: riarylmethane acid dyes, which had strong dyeing ability but poor fastness.
In 1877, the first acid dye acid red A was synthesized for wool dyeing, and its basic structure was determined.
Since 1890, the chromatogram of anthraquinone acid dyes has been more and more complete.
Up to now, there are hundreds of kinds of acid dyes, which are widely used in the dyeing of wool, silk, nylon and other fibers.
2, the characteristics of acid dyes:
The acidic groups in acid dyes are mainly sulfonic (- SO3H), and exist in the form of sodium sulfonate (- SO3Na) on the dye molecule. Some dyes are acidic groups with sodium carboxylate (- COONa).
It is characterized by good water-solubility, bright color, complete chromatographic, simple molecular structure compared with other dyes and lack of longer conjugated coherent system in dye molecules.