Reactive Dyes

(also fiber-reactive dyes), a class of dyes developed between 1952 and 1955. Reactive dyes form covalent chemical bonds with hydroxyl groups when dyeing cellulosic fibers and covalent chemical bonds with amino groups and certain other groups when dyeing protein and polyamide fibers.

The molecules of a reactive dye contain a chromophoric system, which accounts for the dye’s bright, intense color, and a fiber-reactive group, which ensures chemical reaction between dye and fiber. Reactive dyes with highly varied fiber-reactive groups (more than 25) have already found application in industry. Monochloro-symm-triazine and dichloro-symm-triazine often act as reaction groups. In such cases, the reactive dye takes part in the following substitution reaction with ionized cellulose (ZO):

The chromophores (XC) in reactive dyes are primarily azo dyes, anthraquinone dyes, and phthalocyanine dyes. Reactive dyes are available in all colors and are noted for their brightness and excellent fastness. They are widely used for dyeing and printing materials made of cotton, regenerated cellulose, wool, natural silk, and polyamide fiber.