To classify dyes into any particular category is
really an uphill task, for there are plethora of dyes that have evolved
over the years with its typical chemical structures, and commercial
names. Typically a dye-formulation is supposed to have approximately
10-80% pure dyestuff. Generally it is has been observed that for
dyestuffs that are delivered in powder form, a higher value is typically
obtainable. While a lower value is obtained for the liquid formulations.
Here we will try to give a general view of the types of dyes that can
be categorized under a few major classes.
According to a system of chemical classification,
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
|
Colour 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 |
|
Though not very popular but dyes can be categorized
into types by using this method of classification:
- Cationic Dyes
- Anionic Dyes
As globally majority of the dyestuff is primarily
consumed by the
textile industry, So at this level a
classification can be done according to their performances in the dyeing
processes. Worldwide around 60% of the dyestuffs are based on azo dyes
that gets consumed by in the textile finishing process. Major classes of
dyes in textile finishing is given here.
Major Dye classes and the substrates:
- Acid
- Azoic
- Basic
- Direct
- Disperse
- Reactive
- Solvent
- Sulphur
- Vat
- Mordant
A very common classification of the dyestuff is based
on the source from which it is made. Accordingly the classification
could be:
- Natural Dyes
- Synthetic Dyes
A number of other classes have also been established,
based among others on application, that includes the following:
Leather
Dyes - Used for leather.
Oxidation
Dyes - Used mainly for hair.
Optical
Brighteners - Used primarily for textile fibers and paper.
Solvent
Dyes - For application in wood staining and production of
coloured lacquers, solvent inks, waxes and colouring oils etc.
Fluorescent
Dyes - A very innovative dye. Used for application in sports
good etc.
Fuel
Dyes - As the name suggests it is used in fuels.
Smoke
Dyes - Used in military activities.
Sublimation
Dyes - For application in textile printing.
Inkjet
Dyes - Writing industry including the inkjet printers.
Leuco
Dyes - Has a wide variety of applications including electronic
industries and papers.
Chemical classification of the Dyes