Kier bleaching process and recipe in the textile are given below:
Kier is a special pot. Which looks a lot like a cylindrical shell made of stainless steel. Its carrying capacity ranges from 500 pounds to 5 tons. However, more than 3-ton capacity Kier is used. Kier is usually 9 feet high and 6 feet 6 inches wide. Bleaching can be done inside the kier in the form of cloth wrap. There are two types of kier, open kier and closed kier.
Cotton fabrics by Kier are usually bleached in a batch process or discontinuous process. The easiest way to bleach cotton is to use hydrogen peroxide. If the inner part of the kier is cast ion, it causes problems with hydrogen peroxide bleaching. If the inside of the kier is made of stainless steel, there is no problem. Bleaching can also be done in the same kier after scouring. The ratio of products to liquids in Kier Bleaching is kept low.
Caustic Saeda (NaOH) → 0.3 – 0.6% (percentage of fabric weight)
Soda Ass (Na2CO3) → 0.6 – 1.0% (percentage of fabric weight)
Hydrogen peroxide (35%) → 3 – 5% (percentage of fabric weight)
Or, hydrogen peroxide (50%) → 2.5 – 4% (percentage of fabric weight)
Wetting agent → 2-3% (percentage of fabric weight)
Magnesium sulphate →1 ounce / 100 gallons of water
Kier Bleaching process:
Kier bleaching process and recipe in textile. The components are first prepared in a separate tank and then supplied to Kier. One-third of the care is filled by the bleaching solution. The cloth is kept in the bleaching solution while it is wet and the solution is circulated on the cloth by the pump. When half of Kear’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 is circulated and the circulation is kept off for 10 minutes to get the air trapped inside the kier. The temperature is then raised to 60° C and steam circulation is stopped for 10 minutes to re-ventilate. The lid is then closed and the fabric is bleached at 110 ° C for 1 to 3 hours. If Kier is played, bleaching is done for 5 to 6 hours.
90° C to 95° C 8 hours
96° C to 100° C 5 hours
102° C to 105° C 3 hours
110° C 1 hour
120° C to 130° C 20 minutes
However, in the textile industry, the temperature is usually not taken above 110° C. If bleaching is done for only 20 minutes at 120° C to 125° C, the fiber is likely to be damaged.