Azoic Dyes

Dyes containing insoluble azo group (‐N=N‐) are known as Azoic dyes. These dyes are not found in ready made form. They are made by reaction of two different components and the components are Coupling compound (Naphthol) and Dia azo compound or diazo salt. Azoic dyes are used for producing bright color shades like orange, red, scarlet, navy blue and black.

Use of Azoic Dyes:

Azoic dyes are used for dyeing textile fibres mainly cotton fibres but also used for dyeing wool, silk, viscose and synthetic fibres. Azoic dyes are cheap and easy to use to get clear and strong colors.

Dyeing Process of Azoic Dyes:

For Naphthalotion:

To make a naphthol solution first need to add naphthol and glycerine into dyebath.
Then add NaOH into the dyebath.
Finally add salt and water into dyebath.
Then fabric is immersed into this solution for a few minutes.
Finally fabric become naphtholed.

For Base Recipe:

First need to mix required amount of base, HCI, NaNO2 into a dyebath at 0-50°C
Then add acetic acid and sodium acetate and mix them properly.
Finally add thickener and required amounts of water and stirred them properly to get required viscosity.

Printing Process:

Then naphtholed fabric can be printed with base printing paste by block and screen printing method.

Recipe of Azoic Dye:

For Naphtholation:

Naphthol	1.3 gm
Glycerine	1.5 gm
Caustic Soda	2 gm
Common Salt	2 gm
Water	94 cc
Time	20 min
Temperature	Room

For Diazotization:

Base Color	1.5 gm
HCI	1.4 ml
NaNO2	0.6 gm
Acetic Acid	0.8 gm
Sodium Acetate	1.2 gm
Water	As Required
Temperature	00-50°C