8/18/2019 Dyeing of Cotton Fabric With Azoic Dyes

1/3

Dyeing of Cotton Fabric with Azoic Dyes | Dyeing Process o Cotton Goods with

Azoic Dyes 

Name of the experiment: Dyeing of cotton fabric with azoic dyes.

Introdction:The dyes containing insoluble azo group (-N=N-) are known as azoic dyes.

These dyes are not found in readymade form. zoic dyes are produced by a reaction between

two components. The components are!

". #oupling #ompound ( Naphthol)

$. Di-azo %compound or diazo base or diazo salt.

The colored substance formed from this colorless compound is insoluble in water and washingfastness of this shade is e&cellent.

!eaction of Azoic Dye:

Naphtho"ation:

 Naphthols are insoluble in water and they are con'erted into water soluble compound by treating

with alkali.

Diazotization:

base containing amino group (-N$) reacts with the NaN$ (*odium Nitrite) to form a

solution of diazonium chloride of that base in presence of e&cess #l at ++-,+# temperature.Cop"ing# De$e"oping:

The impregnated material is treated in a bath containing diazonium solution to carry out to

coupling and thus color is produced inside the fabric. The maintaining is important.

!ecipe of Azoic Dye:

Naphtho"ation:

 Naphthol = ".gm

/lycerine = ".,gm#austic soda = $ gm

#ommon salt = $ gm

0ater = 12 cc.Time = $+ minute.

Temperature = room.

http://textilelearner.blogspot.com/2012/01/dyeing-of-cotton-fabric-with-azoic-dyes_24.htmlhttp://textilelearner.blogspot.com/2012/01/dyeing-of-cotton-fabric-with-azoic-dyes_24.htmlhttp://textilelearner.blogspot.com/2012/01/dyeing-of-cotton-fabric-with-azoic-dyes_24.htmlhttp://textilelearner.blogspot.com/2012/01/dyeing-of-cotton-fabric-with-azoic-dyes_24.html

8/18/2019 Dyeing of Cotton Fabric With Azoic Dyes

2/3

For diazotization%:

3ase color = "., gm#l = ".2 ml

 NaN$ = +.4 gm

cetic acid = +.5 gm*odium acetate = ".$ gm

0ater = as re6uired to make "++ gm paste

Temperature = ++-,+# (with ice)

Procedre:

For naphtho"ation:

") 7or making naphthol solution8 at first naphthol and glycerine are added in dye bath.

$) Then Na is added into the bath.) 7inally salt and water are added into the bath.

2) Then fabric is immersed into this solution for few minutes. nd the fabric becomesnaphthaled.

For base recipe:

") t first re6uired amount of base8 #l8 NaN$ are mi&ed another dye bath at ++-,+# (with

ice).$) Then acetic acid and sodium acetate are added into the dye bath. nd mi&ed them 'ery well.

) 7inally thickener and re6uired amount of water is added and stirred them 'ery well for getting

re6uired 'iscosity.

Printing process:

The naphtholated fabric is then printed with base printing paste by block and screen printing

method.

After treatment:

fter printing the printed fabric is dried at "++-"+,+ for ,-"+ minute in a dryer.

!emar&:ur naphtholation process was not so sufficient. *o printing becomes une'en. 3ut we learn aboutthe printing of cotton fabric with azoic dye.

Conc"sion:3ecause of high degree of brightness8 ease of application and e&cellent fastness properties

(e&cept rubbing fastness which can be impro'ed by using certain au&iliaries) azoic combinations

(naphthol and bases) are widely used in printing on cellulose fiber fabrics. zoic dyes are usedfor producing bright shade of color such as orange8 red8 scarlet8 na'y blue8 and black color. 3y

http://textilelearner.blogspot.com/2012/01/printing-of-cotton-fabric-with-azoic.htmlhttp://textilelearner.blogspot.com/2012/01/printing-of-cotton-fabric-with-azoic.html

8/18/2019 Dyeing of Cotton Fabric With Azoic Dyes

3/3

this practical we ac6uire knowledge about the printing process of cotton fabric with azoic dyes.

This practical will help us in our study life as well as 9ob life. :special thanks to our teacher and

his assistants for great co-operation.

;ead more! http!