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What are the characteristics of acid dyes and alkaline dyes?
Dec 25, 2018

Acid dyes

It is a kind of water-soluble dyestuff with acidic group in structure, which is dyed in acidic medium. Most acid dyes contain sodium sulfonate, which is soluble in water and has bright color and complete chromatogram. Acidic dyes have complete chromatogram and bright color. The fastness to sunshine and wet treatment varies greatly with dye varieties. Compared with direct dyes, acid dyes are simple in structure, lack of long common double bonds and homoplanar structure, so they are not direct for cellulose fibers and can not be used for dyeing cellulose fibers. Different types of acid dyes have different dyeing properties and different dyeing methods because of their different molecular structures.

Classification: Acidic dyes can be classified into strong acidity, weak acidity, acidic medium and acidic complex dyes according to their chemical structure and dyeing conditions.

Usage: Mainly used for dyeing wool, silk and nylon, and also for leather, paper, ink, etc. It has no colouring power for cellulose fibers.

Alkaline dye

It is also called salt-based dyes. Dyes that can dissociate into cationic pigments in aqueous solution are classified as cationic dyes. It is characterized by bright color, magnificent fluorescence (mainly rose, yellow, orange, etc.) and strong dyeing power, with a small amount of dyes can be obtained deep and lustrous color. The color fastness and light resistance are poor, but the fastness of acrylic fibers (PAN fibers) is better. Basic dyes do not colour cellulose fibers.

Usage: Because of the poor light fastness and wash fastness of dyed fibers with alkaline dyes, it is seldom used in fabric dyeing, mainly used in the coloring of cultural and educational supplies, paper and the manufacture of color lakes.


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