Sulphur Dyeing of Knit Goods

Hosiery Dyeing with Suplphur Dyes:

The dyeing of hosiery fabric in winch and softflow machines - Softflow is more suitable for dyeing sulphur dyes rather than the open winches.

A practical recipe and process method for sulphur dyes application of Knit Goods is as below:

1. Demineralization:
   1. Recipe:
      1. Sirrix 2 UDI = 0.3%
      2. Sandoclean PC = 0.3%
         1. Treat at 70°C for 30 minutes
         2. Hot wash at 70°C for 10 minutes
         3. Cold wash

[ For producing reddish black or dull shades with less rubbing fastness ( dry 3 - 4 and wet 2-3 ) but a 10 to 15% deeper shades go fo Caustic boiling followed by dyeing; whereas for brighter shades and better rubbing fastness and better reproduciable shades, adopt Peroxide bleaching instead of caustic boiling. In caustic boiling the scouring weight loss would be around 6 to 8% and in peroxide bleach, it would be 3 to 5% only. ]

1. Caustic Boil:
   1. Recipe:
      1. Caustic Soda (flakes) = 3~4%
      2. Lissopal D paste = 0.5%
         1. Treat at boil for 2 hours
         2. Hot wash
         3. Cold wash
         4. Neutralize with 2 gpl Acetic Acid at cold.
         5. Check pH - 6 - 7
2. Peroxide Bleaching:
   1. Recipe:
      1. Caustic soda = 1.0%
      2. Stabilizer = 0.5%
      3. Soda Ash = 1.0%
      4. Hydrogen Peroxide (50%) = 2.5%
         1. Treat the fabric at boil for 1 hour.
         2. Hot Wash at 70°C for 20 minutes.
         3. Cold wash - in the same bath add Enzymatic peroxide killer (0.25% to 0.4%) & Acetic Acid 2 gpl; treat for 30 minutes.
         4. Cold wash - check pH - 6 - 7.
3. Sulphur Black Dyeing: Generally people used dye Jet Black shades using sulphur dyes. The dyeing process and pre / post treatment of material are same for any sulphur dyestuff, whether it is black or blue or, brown or green etc.; but the sodium sulohide to be used for vatting would vary from dyestuff to dyestuff. Please check the dyestuff supplier's shade card for this detail.
   1. Recipe:
      1. Calsolene Oil - HS = 1.0%
      2. Soda Ash = 5%
      3. Sodium sulphide = 15%
      4. Sulphur Black OG = 10%
         1. In a plastic trough containing 150 liters of (1:15 ratio) hot boiling water, add Calsolene oil 1% (w/w) and stir well. Add 5% of Soda ash in the trough and stir well. Then add the pure Sodium Sulphide Flakes ( lemon yellow colored is the pure iron free sodium sulphide 60% strength). When all the above 3 components are thorughly dissolved and the temperature is maintainied at 95 to 100°C, add the preweighed quantity of Sulphur Black OG grains dyestuff and stirr well. Allow the contents to become leuco vat for 30 minutes.
         2. Fill the machine with water and raise the temperature to 80~90°C. Keep the machine running. Slowly pump in the dissolved dyestuff in to the machine with in 10 to 15 minutes. Raise the temperature to 95 to 100°C and run for 15 minutes.
         3. Add 15% (w/w) of Glaubers Salt and run at 100°C for 60 to 90 minutes.
         4. Drain the bath
         5. Fill th machine with cold water and run at cold for 10 minutes.
         6. To the same above bath add 2 gpl of Hydros and continue running for another 10 minutes. (This is to avoid oxidation marks, streaks and patches that may arise due to the presence of free sulphur on the fabric.)
         7. Do cold wash thoroughly for 20 minutes.
4. Oxidation:
1. There are two processes for oxidation. You can select any one according to the conditions at your end.
   1. Method-1:
      1. Sodium Dichromate = 0.5%
      2. Acetic Acid = 0.3%
         1. Treat the material at 70°C for 40 minutes.
         2. This method would confer a reddish black with good wash fastness properties.
   2. Method-2:
      1. Sodium Bicarbonate = 1%
         1. Treat the fabric at cold for 10 minutes.(ROOM TEMPERATURE IS ENOUGH).
      2. Hydrogen Peroxide = 1%
      3. Stabilizer 0.5%
         1. Treat the fabric at 50°C for 30 minutes.
5. Hot Wash:
6. First Soaping :
1. Recipe:
   1. Lissopal D paste = 2 gpl
      1. Treat at 95°C for 20 minutes.
      2. Drain.
7. Second Soaping:
1. Recipe:
   1. Lissopal D paste = 1 gpl
      1. Treat at 95°C for 20 minutes.
      2. Drain.
8. Hot Wash
9. Cold wash
10. Finishing:
1. Recipe:
   1. Sodium Acetate = 2%
   2. Avivon SFC = 2% ( CIBA Softener)
      1. Treat the fabric at cold for 10 to 20 minutes.
      2. Drain the bath
      3. Unload (No further washing should be done).