Reactive Dyeing Working Process
Reactive Dyeing – Prepare recipe according to same dyeing condition(temperature, time, process aaa
- Check weigh the substrate sample to within +/- 2%
- Accurately weigh the dye (+/- 2% of the required weight) and dissolve in an accurately volume of water using volumetric flask. The correct level being achieved after dye dissolution. Dye solutions should be stored in stoppered flasks at room temperature and discarded after 2 days (maximum). The solution should be appropriate for the depth of shade to avoid dispensing small volumes. For example
- Add the required volume of dyestuff accurately (preferably via electronic dispensing pipette) Electronic Dispensing Pipettes (EDPs) have a capacity of 10mls. Where larger volumes are required multiple additions will be required.
- Calculate the quantity of water required, allowing for dye and chemical additions, and add to the dyeing vessel.
- Add the required amount of electrolyte and ensure it is thoroughly mixed/dissolved.
- Add the rolled up substrate (avoid folding/creasing) , seal the dyeing vessel and vigorously shake the vessel to ensure even liquor uptake.
- Place the dyeing vessel into the dyeing machine at the pre-set starting temperature.
- Pre-program the dyeing machine to reproduce the bulk dyeing profile. Use Isothermal to represent standard, isothermal and rapid process. If using migration in bulk, the same migration profile should be used in the laboratory.
- At the point of alkali addition, stop the machine and remove the dyeing vessels individually. Accurately add the dilute solution of alkali. Seal the vessel and shake vigorously before placing back in the dyeing machine.
- Run at the set fixation temperature for the prescribed fixation time.
- If recipe have caustic soda addition aside from soda ash, then the machine will just be set for soda ash fixation, and stop the machine for caustic addition. It will be accurately added as diluted solution also. The vessel will be sealed and shake vigorously before placing back in the dyeing machine. Run at the set fixation time mostly 40 minutes.
- At the end of the dyeing stage remove the dyeing vessels from the machine and rinse the dyed samples individually in hot running water for 2 minutes. The dyed samples should then be acidified at 40 degrees for 10 minutes then cold rinse. Soaping with anionic detergent followed at a liquor ratio of 1 : 30 for 15 minutes at the boil. After soaping rinse in warm water for 2 minutes, then squeeze and dry in finishing dryer to have similar drying temperature as in production.