Basic dyes also called cationic dyes, because in solution basic dye molecule ionizes. Causing it’s colored component to become a cation or positively changed radical. In market basic dyes are obtained as a basic salt usually chlorides, but sometimes oxalates or double salts with zinc chloride (ZnCl2).
Basic dye specially used for jute fibre, also used in wool, silk, acrylic dyeing.
Properties of the basic dyes
They are important for high & brilliant shade.
- They are easily soluble in alcohol but not easily in water
- Dyes decomposes at boiled temperature.
- In solution dye protein is cation.
- The basic dyes are poor fastness to light.
- No affinity to cellulosic fibre expect jute fibre.
- They are suitable for protein fibre.
Types of Basic Dye
They are many belonging to this class & they vary considerable in chemical structure. The more important groups are described below-
Group-1: Derivatives of di-phenyle amine.
Group-2: Derivatives of tri-phenyl methane. Example methyl green.
Group-3: Derivatives of thio-zinc. Example methylene blue.
Group-4: Derivatives of azo group. Example: Bismarck brown.