Enzymatic Desizing

Enzymes are specific bio-catalysts of organic origin which are produced by living organisms in living cells and accelerate chemical reactive. The molecular weight height but different from chemical enzymes. The action of enzymes controlled by the temperature, time and pH of the solution. Most enzymes have no action at temperature above 75ºC.
These are soluble in water but insoluble in acid and alcohol.
Desizing enzymes are:
  1. Animal origin: Viveral, Degomma, waste pancrease, cotted blood, liver etc.
  2. Vegetable origin:
    1. Malt extract: Diastator, diastase, malt ostase etc.
    2. Bacterial: Rapidase, biolase, Taka etc.
Desizing condition for enzyme:
Enzyme
Concentrate g/L
Temperature (ºC)
pH
Pancreatic (animal)
1-3
50-60
6-7.5
Malt extract
3-18
50-60
6-7.5
Bacterial
0.5-1
60-70
5.5-7.5
Enzymatic desizing/ continuous desizing process:
          Process: Enzyme = 0.5-2%
                        Time = 1 hours
                        Temperature = 50-60ºC
                        pH = 6-7.5
Desizing procedure:
  1. At first we have to make the desizing mixture. The desizing mixture contains of the following:
i.                    Water.
ii.                  Enzyme.
iii.                Salt.
iv.                Wetting agent.
The above chemicals are dissolved completely in a mixing volume on tank.
schematic-diagram-of-enzymatic-desizing
  1. Then, the desizing enzyme mixture is added to the padding mangle.
  2. Then the fabric is immersed into the desizing liquor.
  3. The temperature of the liquor is raised to 50-60ºC and run for 1 hour.
  4. After desizing, the fabric is squeezed and stored in a storage tank.
  5. Finally cold wash is carried out and then squeezed and dried.

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