In order to prevent the agglomeration of the dye and enhance the dispersibility of the dye, the usual method is to add a dispersant. With the assistance of dispersant, disperse dyes can form a dispersed uniform phase in the dye to complete the dyeing effect.
In order to keep the dye particles in a good suspension and dispersion state during the dyeing process, a large number of anionic surfactants, such as diffusing agent NNO, sodium lignosulfonate, etc., are used in commercial dyes. However, in the high-temperature and high-pressure dye bath, the diffusing agent NNO, etc. is easily resolved from the surface of the disperse dye crystal particles, and the dye particles will further agglomerate and adhere to the cloth surface, causing color spots and dyeing defects.
To solve this problem, we can start from the following two aspects:
1. Choose a dispersant with good thermal stability. Such as the condensate of sulfonic acid sodium salt of phenol or naphthol and formaldehyde.
2. Add other surfactants in the dye bath to increase the stability of the dye bath. Generally, nonionic or anionic surfactants can be added. Although the cloud point of non-ionic surfactants is mostly below 100°C, the cloud point of penetrant JFC is only about 50°C, but due to the existence of anionic surfactants, the cloud point will increase, and it can also be used for high-temperature dyeing. , as long as the variety and dosage are selected properly, it can not only play a good dispersing role, but also play a slow dyeing role to achieve a leveling effect.