Through ultrasonic technology, the particles in the coa […]
Through ultrasonic technology, the particles in the coating can be effectively distributed, instead of the traditional method, the efficiency can be doubled, and the environment can be more scientific and environmentally friendly. Nowadays, there are corresponding coating dispersers on the market. In view of this, I want to talk to you specifically.
The mechanism of ultrasonic paint disperser does not consider the influence of air molecules, water molecules and solvent molecules adsorbed by paint particles. In fact, the surface of the agglomerated paint particles is surrounded by air and water molecules, and the dispersed paint particles are surrounded by a solvent. Air, water and solvents will definitely have an effect on the dispersion process. During the wetting process, the air molecules adsorbed around the coating particles are first replaced by solvent molecules. Then, the coating affinity group in the dispersant molecule is combined with the pigment particles, and anchoring occurs. However, most of the surface of the coating particles are still adsorbed by the solvent molecules. Therefore, it is reasonable to believe that dispersant and solvent form an adsorption competition on the surface of the coating. From the perspective of thermodynamics, because the dispersant molecules are specially designed, they have a competitive advantage in the adsorption force of the coating surface, so that the dispersion system remains stable.
From a kinetic point of view, before the solvent molecules adsorbed on the surface of the coating are replaced by the coating-friendly groups of the dispersant, the surface of the coating particles is surrounded by the solvent molecules. After the dispersant macromolecule is unfolded in the solvent, its molecular chain is also adsorbed by the solvent, that is, it is solvated. Therefore, the solvent molecules on the surface of the paint particles and the solvent molecules around the dispersant molecules must be squeezed out at the same time, and then the combination of the dispersant molecules and the paint particles can be completed. In this process, the van der Waals force between the solvent molecules and the coating particles and the dispersant molecules cannot be ignored, and it shows resistance to dispersion. Therefore, it is conceivable that the ultrasonic coating disperser removes the solvent in this process, or extracts the solvent in the later stage of the dispersion, which is bound to be beneficial to the dispersion. After eliminating the competition of the solvent, due to the increase of the contact area, even if hydrogen bonds and polarization cannot be formed between the coating particles and the dispersant molecules, relying solely on van der Waals forces , a strong anchoring effect can be obtained.
In the case of heating, the dispersant is in a molten state and directly participates in the grinding. In this way, the dispersant molecules are directly combined to replace the air molecules adsorbed on the surface of the coating particles. The advantage of this idea is low energy consumption and high efficiency. The disadvantage is that the viscosity of the dispersant in the molten state cannot be too large, which requires that the relative molecular mass of the dispersant of the ultrasonic coating disperser cannot be too high. Another idea is that a solvent is involved in the early stage, because the solvent can make the coating particles easier to be wetted, that is, the solvent molecules replace the air molecules on the surface of the coating particles, and then the solvent is evaporated by heating or negative pressure or heating and negative pressure at the same time. Promote the close combination of coating particles and dispersant molecules. The advantage of this idea is that i t is suitable for most dispersants. The disadvantage is the high energy consumption of volatile solvents.