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|
|Vacuum Salt or Glauber’s Salt||As Recommended|
|4||Soda Ash||As Recommended|
|8||Dye fixing Agent||Not Necessary|
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:
- For Shades above 7%, two soaping operations are necessary.
- Dye fixing is optional but not a substitute for thorough washing.
- Pressure difference during In->Out and Out ->In operations has to maintain a constant.