Dyeing Method for Cotton and other Cellulosics

Exhaust Application

Application of Azonine and Durantine Dyes to Cellulosic fibre

Azonine dyes are an economical range of direct dyes with good colour values for users where specific fastness properties are not the prime requirement.

Durantine dyes may be used to dye most cellulosic fibres and its blend by exhaust, continuous and printing techniques.

At A add Azonine or Durantine Dye (predissolved)
0.1 to 0.5g/l Neutrasol CR (for shades difficult to level)

At B add y g/l Glaubers salt (anhydrous)
(1/5th of total amount required)*.

At C add z g/l Glaubers salt (anhydrous)
(4/5th of total amount required)*.

At D rinse twice cold.

* See Table

Thoroughly rinse after dyeing to remove loose colour.

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Required total amount of anhydrous Glaubers Salt
for non-mercerised cotton

Percentage Amount of Dye	<>	0.25%-1.0%	1.0%-2.0%	> 2.0%
Amount of Glaubers Salt (g/l)	1-5	5-12	12-20	20-25

For other substrates:

• Mercerised Cotton: reduce the total amount of electrolyte by half
• Viscose: use between 80% and 120% of the amounts indicated for non-mercerised cotton, depending upon the type of fibre. Add 1/3 of Glaubers Salt at start of dyeing and balance at 95-98°C

To improve wet fastness properties after treatment, the dyed substrate may be treated with 1-4% Azofix NW followed by 10 to 30 minutes at 40-60°C in a fresh bath.

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Classification of Direct Dyes

The dyeing conditions to select in practise must take account of the class of levelling properties of the individual direct dyestuffs used. Each Azonine and Durantine Dye has a classification based on the system specified by theSociety of Dyers and Colourists:

1. Self Levelling
2. Salt Controllable
3. Temperature Controllable