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How Are Disperse Dyes Made
May 17, 2018

Disperse dyes are non-ionic dyes with strong hydrophobicity and little water solubility. There are no water-soluble groups in the structure but many polar groups, such as -NO2, -NH2, -CN, -OG, etc. . The dyeing speed of disperse dyes is different due to different dyes. When dyed in color, dyes with similar dyeing rates or good compatibility should be used, such as disperse dyes and weak dyes or neutral dyes. Adjust the color light and increase the level of dyeing to achieve the purpose of learning from each other. The

The dyeing rate of the disperse dyes has a large dependence on the temperature, so the temperature should be controlled especially when dyeing. As the temperature rises, the absorption of the dye by the dispersant is reduced, and collisions between the dye particles increase the chance of condensation. On the other hand, as the temperature increases, the solubility of the small particles and the increase in the size of the large particles are increased, which will decrease the stability of the dispersion. Therefore, the temperature of the prepared dye solution should be low, and it should avoid heating the dye solution for a long time before dyeing. It is generally dyed at 40-50°C and heated to about 0.5°C/min until boiling. According to the leveling and exhaustion of the dye, then heat it again. The

Disperse dyes can dye nylon and polyurethane at the same time. The active group in the dye and PA6 molecules in a large number of amide groups and molecular amino groups at the end of the hydrogen bond, van der Waals force and dipole force to dye and fix. In addition, PA6 molecules contain a large number of non-polar hydrophobic hydrocarbon chains, which is why hydrophobic disperse dyes can be dyed. The disperse dye has a small molecular weight, good diffusibility, simple dyeing method, good levelness, good light fastness, and good coverage, and can avoid the difference in the degree of stretching of the polyamide due to the size of the component and the difference in the degree of spinning. Causes uneven dyeing. However, when PA6 is dyed with disperse dyes, its saturated value is very low and it is difficult to dye dark colors. The

Disperse dyes have better coloration to polyurethanes, which is related to their own molecular structure and relatively tight foaming structure of polyurethanes. Polyurethanes form incomplete and coherent polymer films on the surface and inside of synthetic leather fabrics, and their structures consist of soft segments and hard segments. The loose structure of the soft segment is the main position of disperse dye uptake. Polyurethane absorbs a large amount of disperse dyes, and the residual amount of dyes in the dyeing residual liquid is small. This is necessary for dyeing dark colors using a high-dispersible disperse dye. Within a certain range, with the increase of the dyeing temperature, the color yield is larger. In addition, the disperse dyes have good color fastness to polyurethane. The

In the dyeing of island-type microfiber synthetic leathers, disperse dyes are the main dye type for dyed polyurethanes. In contrast, other types of dyes have poor coloring on polyurethanes, on the contrary, on the nylon coloring; some have better coloring of polyurethane, but on the nylon coloring, which is uniform for dyeing Light, colorless finished products are very unfavorable. Even if it is a disperse dye, the amount should be controlled, because the color of nylon will not only affect its color, but also affect the color fastness of nylon.