Cotton fabric dyeing process by vat dye:
The method of dyeing cotton fabric by vat dye is discussed below:
Dyestuff →3% (on product weight)
Caustic Soda → 10% (on product weight)
T. R Oil → 2-3% (on product weight)
Sodium hydrosulphide → 4-8% (on product weight)
Common salt → 8-10% (on product weight)
Water →20 times
Temperature → 60°C
Time → 45 to 60 minutes
Cotton fabric dyeing process:
This dye is insoluble in water. It has to be converted into leuko compound to make it soluble in water. There are two types of VAT colors available in the market – liquid, and powder. When in a liquid state it can be converted directly into leuko compound. And if the dye is in powder, according to the recipe, you have to mix water with T.R oil. In this case, the solution should be stirred well, resulting in a paste. https://bdfabric.com/vat-dye-and-its-application-in-textile/
Cotton fabric dyeing process by vat dye. It is then converted into leuko compound by the addition of sodium hydrosulfide, caustic soda, and salt. As a result, the vat dye dissolves in the water and can dye the fabric. In this case, the solution is kept still for a while. If the sediment does not fall, then the solution must be prepared. And if the sediment falls, it must be understood that the leuko compound is not well-formed.
In that case, the leuko compound has to be made well again. The solution is then brought to the dye bath. The dye bath is well mixed with the remaining water and the lid is closed to prevent air from entering. Then it is stirred at a temperature of 60°C for 45 minutes to 60 minutes. In the fall, the cloth is lifted from the bath, squeezed, and washed with an acetic acid solution to remove alkali.
It is then washed in cold clear water and spread in the air. As a result, the dye becomes insoluble in the reaction of the air with oxygen and returns to its former state and the color becomes permanent. It is then oxidized.