Precautions For Sulphur Black Dyeing

1. Sulphur black dye is not suitable for water, so sulphur dye itself has no dyeing ability for cotton. However, it has good dyeing performance for cotton when the dye is reduced to leucocyte in aqueous solution of alkali sulfide. Dyeing with sulfurized dyes is carried out in sulfurized alkali solution.

2. Operation of vulcanized dyes and chemicals: dissolve the prepared vulcanized alkali in 80 ℃ water for 5-10 minutes in the attached cylinder, and then dissolve it in boiling water for 20 minutes in the sulphur black. Add 1% sodium carbonate with sulphur black content.

3.Function and dosage of each auxiliary agent:

Sulfide alkali (Na2S): It is a solvent for dissolving sulfur dyes. Its function is to reduce sulphur black to the leucophore of dyes and has the ability to dye cotton. It plays the role of reducing and dissolving sulphur black .

Dosage: the ratio of alkali sulfide tosulphur black is 1-1.5: 1

Soda ash (Na2CO3): Soda ash plays a role in improving the reduction stability of the dye solution in the sulphur black dyeing solution to prevent premature oxidation of the dye. It is also an alkaline agent for oil removal. When using hard water for dyeing, it can also prevent the calcium and magnesium salts in hard water from affecting the dyeing effect. Generally, the dosage is about 2% of the fabric. Excessive dosage will make the fabric red-brown.

Sodium sulfate (Na2SO4): The dye uptake of sulfide dyes is low. Adding sodium sulfate to the dye solution can help improve the dye uptake, so sodium sulfate plays a role in promoting dyeing.

Degreasing agent: remove the oil stain on the cloth and improve the penetration effect of the embryo cloth, improve the dye uptake and level-dyeing sulphur black dyeing.