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DYEING PROCEDURE -
DYEING METHODS
Winch, jet, package &
beam dyeing machines
These dyes are specially designed for exhaust dyeing methods. The dyeing
method selection depends upon the type of substrate to be dyed and the
machinery to be used for dyeing.
|
Depth of Shade |
Salt |
|
Unmercerised cotton(gm/l) |
Mercerised cotton or Viscose Rayon |
Soda
Ash (gms/l) |
Fixation time (min.) |
| Upto 0.10% |
10 |
5 |
10 |
30 |
| 0.11-0.30% |
20 |
10 |
10 |
30 |
| 0.31-0.50% |
30 |
20 |
10 |
45 |
| 0.51-1.00% |
45 |
30 |
15 |
45 |
| 1.01-2.00% |
60 |
40 |
15 |
45 |
| 2.01-4.00% |
70 |
55 |
20 |
60 |
| Above 4.00% |
90 |
65 |
20 |
60 |
Method No. 1 : Salt addition in portions (suitable for mercerized yarn)
This process is
recommended for non-circulating liquor machinery and it is suitable for all
depths of shade.
Method No. 2 : Salt addition at start (Suitable for unmercerised yarn)
This method is
recommended for machines with liquor circulation and it is suitable for
medium to heavy depth of shades.
Method No. 3 : Both salt & alkali addition at start
The method is
recommended for machines with liquor circulation, primarily for the dyeing
of medium - heavy binary combinations. It is suitable for unmercerised
cotton.
Note 1: A mixture of soda ash
and caustic soda is recommended alkali for this method.
| Depth of Shade |
Soda ash gms/l |
Caustic Soda 100% gms/l |
| Upto 1.0% |
5 |
0.2 |
| 1.01 to above |
5 |
0.5 |
Method No. 4 : (Dyeing Pale Shade) (Garment dyeing)
The method is
recommended for machines with microprocessor controlled addition system for
dyeing pale shades (less than 0.5% depth) and for all shades on mercerized
cotton & viscose packages
Method No. 5 : Isothermal Method (Dyeing heavy shades garment)
The method is
recommended for machines with microprocessor controlled addition systems for
medium to heavy depths ( >than 0.5% depth) on unmercerised cotton.
Dyeing method for Jigger machines
Due to high temperature
dyeing the problems of off-shade selvedges of too pale selvedges are often
encountered in dyeing with these machines. The following precautions hence
should be taken to avoid such problems.
- To use closed type jiggers so that a uniform temperature is possible
across the width of fabric.
- Batch the fabric evenly.
- Maintain the dye bath at minimum of 85-90oC during salt
stage.
-
Adjust the dye bath temperature 85-90oC to
ensure that fabric is maintained at minimum 80oC during alkali
addition stage.
Procedure
Set the dye bath at 90oC
with resist salt 2 gms/l. Now add 1/2 amt. of dye and run one end. Then add
remaining 1/2 amt. & run another one end. Add 1/2 amt. of salt & run one
end. Add remaining 1/2 amt. Of salt and run another end. Maintain 80oC
temperature continue to run for 2 ends. Now add 1/2 amt. of soda ash & run
for one end. Then add remaining 1/2 amt. Soda ash & run for another one end.
Then add remaining 1/2 amt. soda ash & run for another one end. Then run for
4 ends or more if required & wash. (1 end =10 minutes)
Dyeing method for cotton / polyester blend
The one bath two stage dyeing method for polyester / cotton blend is
applicable on jet, beam or package dyeing machines.
| 2 gm/l Buffer pH 5 (5.5) |
X% GAAYACTIVE 'HE' dye |
| 1 gm/l Anionic
dispersant |
50 gms/l Salt |
| X% Disperse Dye |
15 gms/l T.S.P. Soda ash |
Salt and alkali requirements
| Depth
of Shade % on total weight of goods |
Salt
(gms/l) |
Soda
Ash (gms/l) |
| Upto 0.2% |
15 |
10 |
| 0.21-0.4% |
20 |
15 |
| 0.41-0.80% |
30 |
15 |
| 0.81-1.6% |
50 |
20 |
| Aabove 1.6% |
70 |
20 |
Washing - off procedure
In order to obtain
maximum wet-fastness properties, brightness and purity of shades with
consistent dyeing results, it is essential to give a through 'Soaping' to
clear-off unreached hydrolyzed dye form the dyed fabric.
The dyed fabric is rinsed repeatedly in cold water to remove most of the
alkali, salt and unfixed dye present and rinse again in warm water not
higher than 60oC. then run in a bath containing:
Anionic detergent - 1-2 gms/liter for 15 minutes at the boil. Then rinse in
warm water (up to 60oC) and finally in cold water. The most
satisfactory results in washing-off, particularly for piece goods, are
obtained by employing an Open soaper or perforated beam-washing machine. If
such equipments are not available, conventional ones like jig or winch may
be used. For yarn in the hank form open-vat is employed and for yarn in
packaged form the package-dyeing machine itself used.
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