The nature of the dye solution

Water -soluble dyes generally contain water -soluble genes, such as sulfonic acid, carboxyl groups, etc. This type of dye can be dissolved in the aquatic solution. The size of the solubility is related to factors such as the type of dye, temperature, and dye pH value. Water -soluble dyes are generally electrolytes, and ionization occurs in the solution. The pigment ion type generated after ionization is divided into pussy -type dyes and codonic dyes. Poton -type dyes include direct dyes, active dyes, acidic dyes, etc., and the dye anion is generated after ionization. Such as acid red g of ionization as follows:

The pigment ions generated after ionization in the water after the ion -type dye are cationic, and the formula can be expressed as:

Dx+ d + x-

D+represents dye cation, and X-represents anion (mostly CI-a few is ½SO24-).

Dispersion of dyes

Diversified dyes and reduction dyes are enjoys dye. The solubility in the water is very small. During dyeing, dyes are mainly decentralized in the water. The hydrophilic group that depends on the decentralized agent is scattered in the solution to form a stable suspension.

In the dye solution, some dyes are suspended in the dye fluid in a small crystal state, and some dyes are dissolved in the scattered beam. A small part of the dye is dissolved. These three states maintain a certain dynamic balance relationship. When restoring dyes and decentralized dyes, the decentralized stability of the dye solution must be ensured. If the decentralized stability of the dye liquid decreases, the dye particles are easy to precipitate, and the dyeing shelter is easily formed on the cloth surface.

The decentralization of dyes is related to the size of the dye particles, the temperature of the dye, the electrolyte, and the performance of the dispersant. If the dye particles are too large, it is prone to precipitation, which requires that the dye particles are less than 2 microns; the temperature of the dye liquid rises, the stability of the dye solution is different, and even the precipitation will be added; Reducing; decentralization of dispersers has a great impact on the stability of the dye solution.

In the dye solution, the dye not only has the force (affinity) between the fiber, but also the force between the dye ions or between the dye ions and the dye molecules, which causes the dye ion or dye molecules to gather to varying degrees to form dye aggregation Body, thereby decreased the stability of the dye solution. The aggregation tendency of dyes is related to the structure of the dye molecules, the temperature of the dye, the electrolyte concentration, and the concentration of the dye.

The dye molecular structure is complicated, the molecular weight is large, and the co -pyramid system with the same plane. The force between the dyes molecules is strong, and the dyes are easy to gather; the temperature of the dye liquid is reduced, and the dye particles have decreased. Therefore, the temperature decreases, and the tendency of dye aggregation will further increase; adding electrolytes to the dye solution will reduce the Curon's exclusion between ionic dyes, increase the tendency of dyes to significantly increase, and even precipitate; high dye concentration, the number of dyes in the unit volume The chance of collision with each other is high, and the tendency to gather.

There is a dynamic balance between dye ions, dye molecules and its gathering collectives in the dye solution, that is, the dynamic balance of gathering and solving. During dyeing, the upper dye of the dye is performed in a single molecule or ionic state. As the dye molecules are constantly dyeing fiber in the dye liquid, the dye concentration of the single molecule or ionic state in the dye liquid gradually decreases. Gather until the dyeing reaches a balance.