Bi-functional dyes are applicable by both exhaust and pad-dyeing procedures.
A) Exhaust dyeing Procedure
Bi-functional dyes are applicable by exhaust dyeing methods as given as per
below mentioned :-
(i) Increase temperature method
Set the dye-bath 250 C with dye solution and carry out dyeing for
10Min. Then add half amount of salt and continue dyeing by raising temperature
to 450C in 10Min. Add remaining half the amount of salt at 450C
and raise the temperature to 600C in 10Min. with continued dyeing.
Continue dyeing 600C for next 5Min. and then add half amount of soda
ash and dyeing is continued for further 50Min at 600C. The goods are
then washed off.
Salt & Alkali Requirements:
% Shade *
Soda Ash gms/l
1.0 to 2.0
2.0 to above
35 to 50
*For light shades of less than 1%, quantity of Glauber's salt and
soda ash to be reduced appropriately.
Temperature increasing method.
This method gives better levelness when it is difficult to obtain level dyeing.
(B) Constant temperature method.
Set the dye-bath at 600C with the dye solution. Carry out dyeing at
600C for 10 Min. Then add salt at 600C and continue dyeing
for 25Min. Add half the amount of soda ash and continue dyeing for 10Min. Then
add remaining half amount of soda ash and continue dyeing for further 50Min. at
600C and goods are then washed off.
Salt & Alkali requirements: same as (8)
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