The chemical method of vat dyes

The dissolution process of vat dye is a reduction reaction process. When dissolving, the dissolution temperature should be determined according to the reducing conditions of the reducing agent used. For example, the commonly used reducing agent for vat dyes is sodium hydroxide, and the best use temperature in the solution is 60°C. If the temperature is too high, it will cause a large amount of decomposition of sodium hydroxide.

(1) Full bath method:

Put the dye into the dye cup, add red oil and a small amount of warm soft water to mix thoroughly, then add the specified amount of caustic soda and sodium hydroxide, then add soft water to the required bath volume, and reduce at 55°C.

(2) Dry tank method:

Put the dye into the dyeing cup, add red oil and a small amount of warm soft water and mix thoroughly, then add two-thirds of the amount of caustic soda and sodium hydroxide to make the amount of dyeing solution one-third of the total amount, according to the reducing conditions of the reducing agent used To determine the temperature of dissolution. Add the remaining caustic soda and sodium hydroxide to the dye cup, and add soft water to the required bath volume.