Level dyeing problem of reactive dyes

When reactive dyes are dyed, special bath softeners have been used to prevent rope creases or to promote dye penetration.

Since reactive dyes are water-soluble, anionic levelling agents are generally not used. However, some reactive dyes have low solubility in alkaline dye baths or are prone to association in dye baths. At this time, it is very effective to add leveling agents.

In alkaline dye baths, representative dyes with low solubility include C.I. Reactive Blue 19 and so on. The dye was originally of the Sulfate ethyl Sulfone type with good solubility. However, after the addition of an alkali agent, the chemical structure was changed to the vinyl sulfone type, and the solubility was greatly reduced, resulting in dye aggregation.

C. I. Chemical structure changes in Reactive Blue 19 alkaline bath

At this time, by adding an anionic leveling agent to promote dispersion and melting to obtain level dyeing and stable dyeing reproducibility.

The representative dye that is prone to association itself is the phthalocyanine type Rurq. Blue dye (for example, C.I. Reactive Blue 21, etc.). If combined with a leveling agent, it can improve the solubility stability and improve the solubility. However, this kind of dyes will produce slow dyeing after adding leveling agent, so when they are used in excess, they will have poor dyeing depth. It is recommended to strictly control the dosage.

In addition, as the overall tendency of reactive dyes, when metal ions are contained in the dyeing water, the solubility of the dye may be reduced due to the influence of the metal ions in the water. In this case, adding a leveling agent is also very effective. The leveling agent suitable for the above-mentioned purposes includes Sumipon SE.