Azoic dye definition is – any of a group of water-insoluble azo dyes formed by coupling of the components on the fiber —called also ice color, ingrain dye. The dyes containing azo groups – N = N – are called Azoic Dye. These are not ready made dyes but are produced by reaction of two. Structure, Chemical Name, CAS, MF. 4-Chloronitroaniline · , C6H5ClN2O2. 3-Chloromethylaniline · , C7H8ClN. 2-Amino

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Properties and Advantages of Azoic Dye – Textile Chapter

Explore to learn and share Azoic dye also named as Napthol, Branthol, Magic and Ice color. Dye formation in fiber occurs on the basis of coupling reaction. Normally two baths are needed for dyeing: These dye stuffs always contain Azo groups in its chemical structure. Light fastness property is admirable. Brightness of shade is also admirable.

It is directly insoluble in water. These dye stuffs are always used in dyeing cellulosic material. Here dyeing operation is completed by two bath arrangement. One is called impregnation bath and another is called developing bath. Alkali resistance is poor to good. Index is 2 to 4. Suitable for lighter shade dyeing Light resistance: Poor to very good, Index 2 — 7.

This dye stuff is called developed dye due to formation of dye in fiber during dyeing process. Addition of salt increases the substantivity.

Napthol dispersed in alcohol, T. Why Azo Dye is dyed called? This color contains insoluble azo groups in its chemical structure.

The coupling component is finally soluble in diazotization reaction. Two steps are required by dyeing with azoic color. In the first step textile goods are dyed by Napthol color. In the 2nd bath, Base or Salt is used for dyeing. After 2 — 3 minutes dyeing in 2nd bath, the azoic color is seen in the textile goods magically. For this reason this dye is called Magic color.


Azoix coupling components are insoluble in water.

An overview of Azo dyes – Textile Apex

To make them soluble in water the textile materials are impregnated in a solution of Dues and NaOH. As the first coupling component is Napthol color. Azoic dyes contain Azo group and final color is insoluble in water, so it is called Aoic Pigment.

General procedure for dyeing cellulosic material with Azo Dyes.

Two bath of individual recipe is used for dyeing with azo dyes. Impregnation Bath 1st bath. Developing Bath 2nd bath. Then add slowly in it, the azkic hot water and stir mix constantly. Now the bath is ready for steeping textile goods for a few minutes In this bath, any naptholated goods, excepting the napthol AS — G will look yellow. In the developing bath salt is dissolved with hot water and then cold water added in the bath.

Finally add NaCl in the developing bath.

eyes Now treating the above naptholated or impregnated goods for 2 — 3 minutes in this bath. It will be noted that the color will develop the goods magically. Now steep the textile goods for a while after developing a bath contains 1. It is done only for neutralization of goods.

Azoic dyes

Then squeeze and dry. In this way, dyeing procedure is completed. Function of azzoic chemicals used in Napthol Dyeing. Difference between Fast Salt and Fast Base.

An overview of Azo dyes

Stripping method of Azoic color: Azoic dye stuffs once developed are very difficult to strip. The yellow combination with AS xzoic G and those with napthol of high substantivity are the most difficult one to strip. In order to affect satisfactory stripping Lissol Amine — A is used. It acts as a stripping promoter, when used in conjunction with a reducing agent like sodium hydro-sulphide and alkali.


Now boil for 20 to 30 minutes until the shade is reduced to a pale Light yellow or brown color.

The quantity of hydro — sulphide is increased in the case of yellow combination. Trade name of Azoic color. Test method of Azoic color.

Now treat the sample up to boiling stage. Then we will observe the color will come out completely from that sample. Now this liquor and sample are to come in an oxidizing action in the presence of air or an oxidizing agent. If the color is not received to it, then it will indicate that the dyss are dyed or printed with azoic color.

All syes chemicals according to the recipe are mixed with water to make a suitable solution. This is known as diazotization.

To remove excess HCl we should use Na — Acetate. To protect from sunlight, we can use Al — sulphate. Asadur Rahman March 21, at 9: Popular Posts Sewing thread: Definition, types and end uses Fabric Selvage Definition and types of yarn count Types and flow-chart of jute processing What is Resin finishing?