Type of Dyes

The Dyes are classified based on the products to which they can be applied and the chemical nature of each dye. Dyes are complex unsaturated aromatic having characteristics like solubility, intense color, substansiveness and fastness.

A dye-formulation is supposed to have approximately 10-80% pure dyestuff. It is mostly observed that dyestuffs delivered in powder form have a higher value. While a lower value is obtained for the liquid formulations.

Dyes may be classified in several ways (e.g., according to chemical constitution, application class, end-use).

Dyes can be divided according to the nature of their Chromophore:

	Group	Uses
Category:	Acridine dyes, derivatives of acridine >C=N-and>C=C	Textiles, leather
Category:	Anthraquinone dyes, derivatives of anthraquinone >C=O and>C=C	Textiles
Category:	Arylmethane dyes Diarylmethane dyes, based on diphenyl methane Triarylmethane dyes, based on triphenyl methane
Category:	Azo dyes, based on a -N=N- azo structure
Category:	Cyanine dyes, derivatives of phthalocyanine
Category:	Diazonium dyes, based on diazonium salts
Category:	Nitro dyes, based on the -NO2 nitro functional group
Category:	Nitroso dyes, are based on a -N=O nitroso functional
Category:	Phthalocyanine dyes, derivatives of phthalocyanine >C=N	Paper
Category:	Quinone-imine dyes, derivatives of quinone	Wool and paper
Category:	Azin dyes Eurhodin dyes Safranin dyes, derivatives of safranin -C-N=C- -C-N-C	Leather and textile
Category:	Xanthene dyes, derived from xanthene -O-C6H4-0	Cotton, Silk and Wool
Category:	Indophenol dyes, derivatives of indophenol >C=N-and>C=O	Color photography
Category:	Oxazin dyes, derivatives of oxazin -C-N=C =C-O-C=	Calico printing
Category:	Oxazone dyes, derivatives of oxazone
Category:	Thiazin dyes, derivatives of thiazin
Category:	Thiazole dyes, derivatives of thiazole >C=N-and-S-0=	Intermediate
Category:	Fluorene dyes, derivatives of fluorene
Category:	Rhodamine dyes, derivatives of rhodamine
Category:	Pyronin dyes

According to the Nuclear Structure, dyes are categorized into two groups

• Cationic Dyes
• Anionic Dyes

Textile Industries use dyestuff in large amount, so at this level a classification can be done according to their performances in the dyeing processes. The most consumable dye is Azo dye, around 60% of the total dyestuffs of the world are based on this dyes. Major classes of dyes in textile finishing is given here:

• Acid
• Azoic
• Basic
• Direct
• Disperse
• Reactive
• Solvent
• Sulphur
• Vat
• Mordant

Classification of dyestuff is mainly depend upon the nature of the source from which it is made. Accordingly the classification could be:

• Natural Dyes
• Synthetic Dyes

Based on various applications, a number of other classes of dyes have also been established, that includes the following:

• Optical Brighteners - Used primarily for textile fibres and paper.
• Fluorescent Dyes - A very innovative dye. Used for application in sports good etc.
• Leuco Dyes - Has a wide variety of applications including electronic industries and papers.
• Oxidation Dyes - Used mainly for hair.
• Leather Dyes - Used for leather.
• Fuel Dyes - As the name suggests it is used in fuels.
• Solvent Dyes - For application in wood staining and production of colored lacquers, solvent inks, waxes and coloring oils etc.
• Inkjet Dyes - Writing industry including the inkjet printers.
• Smoke Dyes - Used in military activities.
• Sublimation Dyes - For application in textile printing.