January 23, 2009

Package Dyeing (HT HP) - Cheese Yarn Dyeing-II

Reactive Dyeing of cotton yarn in cheese form:

Whether it is Vinylsulphone or Bifunctional dyestuff, you may follow the following dyeing cycle for yarn dyeing:

The Chemical table shown below contains a
Code No. that has to be included time to time when the dyeing process is going on.

Code No Name of Chemical Grams/liter
1 Acetic Acid 0.5
Sequestering Agent 0.5
2 Acetic Acid 0.5
Vacuum Salt or Glauber's Salt As Recommended
3 Dyestuff O.W.F.
4 Soda Ash As Recommended
5 Acetic Acid 0.5
6 Sequestering Agent 0.5
Anionic Soap 0.5
7 Acetic Acid 0.5
8 Dye fixing Agent Not Necessary
9 Softener 1.0

Processing Cycle for Yarn Dyeing:

  • Set the dye bath with soft water at ambient temperature and as per MLR
  • Enter the RFD (Ready For Dyeing) yarn in to the processing vessel.
  • Add Chemical [Code-1]. Circulate for 3 minutes (In -> Out) and hold for 10 minutes. Drain.
  • Check pH. It should be 6 - 7. Check for channeling.
  • Fill cold water, add chemicals [Code-2], Circulate for 5 minutes (In -> Out) and hold for 10 minutes.
  • Raise temperature to 40°C and hold for 5 minutes.
  • Add dissolved dyestuff [Code-3] in 2 to 3 portions with Out -> In circulation at 40°C.
  • Raise temperature to 60°C @ 1.5°C/minute and hold for 15 minutes.
  • Add Chemicals [Code-4] in two parts with In->Out circulation and run for 45 minutes.
  • Check the sample and drain the dye bath.
  • Rinse at room temperature for 5 minutes and drain.
  • Give overflow rinse as per the dept of shade - 3 to 5 minutes.
  • Fill fresh water, add chemicals [Code-5] and hold for 5 minutes. Drain.
  • Fill hot water (60°C), add chemicals [Code-6] and circulate for 3 minutes.
  • Raise the temperature to 95°C and run for 15 minutes. Drain.
  • Rinse at 70°C for 10 minutes followed by 5 minutes overflow wash. Drain.
  • Fill fresh cold water, add chemicals [Code-7] & [Code-8] and circulate for 3 minutes, hold for 15 minutes and then drain.
  • Fill Cold water, add chemicals [Code-9], circulate for 3 minutes and hold for 10 minutes. Drain.
  • Unload the batch.
Notes on Dyeing:
  1. For Shades above 7%, two soaping operations are necessary.
  2. Dye fixing is optional but not a substitute for thorough washing.
  3. Pressure difference during In->Out and Out ->In operations has to maintain a constant.
In->Out 100 - 140 KPA
Out->In 90 - 120 KPA