Preparation method of liquid disperse dye for jigger dyeing machine

Wetting of disperse dyes
When the disperse dye solid particles come into contact with the dispersion medium water, the original solid-gas interface on the surface of the dye particles is replaced by a new solid-liquid interface. This is the process in which the surface of the disperse dye particles is wetted by water. Only by wetting can water quickly penetrate into the internal and external surfaces of the disperse dye solid, thereby improving the grinding efficiency of the disperse dye.
Under strong mechanical grinding, for some medium and low molecular weight disperse dyes, it is difficult for the wetting agent to improve the grinding efficiency. However, for high molecular weight, hydrophobic disperse dyes, when there are a large number of particle gaps in the disperse dye filter cake, in order to improve the grinding efficiency of the disperse dye, it is very necessary to select a surfactant with strong wetting effect.
Mechanical dispersion of dye aggregates
Disperse dyes aggregate and crystallize into aggregates (particles) due to the dispersion force and hydrogen bonding between molecules. It is difficult for water to penetrate into its internal and external surfaces through wetting and penetration, weakening or releasing the force between dye molecules. This requires the application of a certain external force (such as the grinding effect of a grinder, the cavitation effect of ultrasonic waves, high-speed shearing force or the combination of the above forces, etc.) to break the force between dye molecules, causing cracks in the dispersed dye particles to separate fine particles. change.
During the grinding and dispersion process, the surfactant in the water dispersion system will form a dense adsorption layer on the surface of the depolymerized dye. Through electrostatic repulsion or steric hindrance, it will hinder the re-aggregation of the depolymerized dye or the cracks in the dye aggregates that have been generated. Re-close to achieve the purpose of dispersion. Under the action of multiple mechanical grinding and dispersant dispersion, the disperse dye particles are gradually ground, dispersed and refined into smaller disperse dye aggregates until they become nanometer disperse dye particles. At present, the mechanical dispersion methods of disperse dyes mainly include mechanical grinding method, ultrasonic-mechanical composite grinding method, high-speed homogenization method, etc.
Stabilization of nanoscale disperse dye aqueous dispersions
Due to the large solid-liquid interface between the nano-dispersed dye particles and water, the system has a high interfacial energy and is a thermodynamically unstable system. Significant flocculation, agglomeration or sedimentation will occur during the placement process. The grinded and pulverized nano-dispersed dye particles aggregate in water due to hydrophobic force, van der Waals force or hydrogen bonding between dye molecules, forming soft agglomerates or dye recrystallization to produce hard agglomerates (crystals).