Dyeing of cotton knitted fabric with reactive dyes

The characteristics of reactive dyes

1. Reactive dyes are soluble in water and contain active genes in the molecular structure. Under certain conditions, they can covalently bond with the hydroxyl groups on cellulose fibers.

2. Reactive dyes have bright colors, good wet processing fastness and rubbing fastness, good level dyeing, uniform chromatogram, convenient application, and good light fastness.

Some main factors affecting the dyeing of reactive dyes

1. The influence of affinity

1.1 When dyeing with dyes with high affinity, it has a relatively high percentage of dyeing, which is beneficial to improve the utilization of dyes, but washing must be strengthened, otherwise it will affect the washing and rubbing fastness of the dyed material.

2. The influence of liquor ratio

2.1 When dyeing with reactive dyes, the bath ratio should be reduced as much as possible without affecting level dyeing. This improves the fixation rate and reduces the hydrolysis of reactive dyes in the dyeing bath.

3. The influence of temperature

3.1 K type reactive dyes, it is necessary to dye at a higher temperature.

X-type reactive dyes can promote the hydrolysis of dyes as the temperature rises, but they cannot be dyed at high temperatures.

3.2 The influence of alkali agent: In the case of ensuring color fixation, a lower PH should be selected as much as possible, and generally the pH should be controlled at 10-11.

3.3 The influence of electrolyte: The reactive dye has small molecules, good diffusion performance, and good leveling effect. Therefore, dyeing should add a larger amount of electrolyte to promote dyeing.