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In this method of dyeing, difficult
combinations and shades may be dyed.
Method of dyeing:
- Make ready the dye bath with sharpening chemicals and auxiliaries.
- Raise the temperature to 80°C.
- Add the dyestuff in to the bath slowly over a period of
time ( may 20 minutes).
- After addition of dyestuff, add the required amount of
salt in two portions or slowly ( 20 minutes).
- The add Soda ash to the dye bath in 2 portions or over a
period of 20 minutes.
- Continue dyeing at 80°C for 20
minutes.
- Reduce the temperature slowly to 60 over 20
minutes.
- Dye at 60'C for another 30 minutes.
- Take sample. If the shade is slightly lighter (10%
~15%).
- Continue dyeing for 30 minutes, and check
the shade. Even then if it is not matching to the standard, very small
additions you can make. If the requirement of additional dyestuff is great
then drain the bath. Make 2 hot washes followed 2 cold wash and
neutralization. take out the batch from the machine. Take a sample from
the batch and try over dyeing in the lab to find out the exact additional quantity
of dyestuff. Set fresh water bath and do the procedures from 1 to 7.
Salt and Soda requirement:
| Depth of Shade |
Vacuum Salt gms/liter |
Soda Ash gms/liter |
| 0.1 ~ 0.5% |
30 |
10 |
| 0.5 ~ 1.0% |
40 |
10 |
| 1.0 ~ 2.0% |
60 |
15 |
| 2.0 ~ 4.0% |
70 |
20 |
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