Hydrogen peroxide bleaching of cotton fabric:
Bleaching of cotton fabric by hydrogen peroxide in Kier boiler machine is the easiest method. However, the inside of such kier is given a coating of sodium silicate and cement. However, the inner part of the kier is made of stainless steel and does not require coating. It can also be bleached in the same kier after the scouring process. When bleaching hydrogen peroxide, the ratio of liquid is kept low.
Hydrogen peroxide bleaching of cotton fabric-Recipe:
Caustic Soda → 0.3% to 0.8% (percentage of fabric weight)
Soda Ash → 0.8% to 1.0% (percentage of fabric weight)
Hydrogen peroxide (35%) → 3% to 5% (percentage of fabric weight)
Hydrogen peroxide (50%)→ 2.5% to 4% (percentage of fabric weight)
Wetting agent→ 0.5% to 1% (percentage of fabric weight)
Sodium silicate → 2% to 3% (percentage of fabric weight)
Magnesium sulphate: 1 ounce / 100 gallons of water
Hydrogen peroxide bleaching of cotton fabric-Bleaching Process:
The components are first prepared in a separate tank and then supplied to Kier. One-third of the kier is filled by the bleaching solution. The fabric is placed in the bleaching solution and circulated on the dissolved fabric by the pump. When half of Kier’s cloth is full, steam is driven and when Kier’s cloth is full, the temperature is kept at 40°C to 45°C. The temperature is then raised from 60°C to 65°C and kept for 30 minutes. Steam circulation is kept off for 10 minutes to remove the air trapped inside the key.
The temperature is then raised to 80°C and steam circulation is stopped for 10 minutes to re-ventilate. The lid is then closed, and the cotton cloth is bleached at 110°C for 1 to 3 hours. If Kier is open, bleaching is done for 5 to 6 hours. However, the temperature can be increased to reduce the time of bleaching. However, in the textile industry, the temperature is not usually raised above 110°C. Because the fiber is likely to be damaged. The cloth is then washed first with hot water and then with cold water to prepare for the next process. Thus cotton cloth is bleached with hydrogen peroxide.