What are the dyeing techniques of direct dyes

The dyeing method of direct dyes is relatively simple, and can be dyed by dip dyeing, coil dyeing, pad dyeing and coil dyeing.

Direct dyes will interact with calcium, magnesium, and iron in hard water to form precipitates, which will reduce the utilization of dyes and may cause stains and other defects. Therefore, soft water should be used for dissolving dyes and dyeing water. The dye liquor generally contains dye, soda ash, table salt or sodium sulfate during dip dyeing. The amount of dye depends on the color requirements. Soda ash helps the dye to dissolve and also has the effect of softening water quality. The dosage is generally 1--3g\L. Trisodium phosphate or sodium hexametaphosphate can also be used, the latter is an excellent water softener. Table salt or sodium sulfate is used to promote dyeing, and the dosage is generally 0-20g\L. For dyes with insignificant promoting effect or when dyeing light colors, table salt can be less or not added.