In various coating auxiliaries, wetting agents and dispersing agents are surfactants, so sometimes people distinguish between the two, what is the difference between them?
First, the roles of the two are different. Wetting usually refers to the spreading of liquid on a solid surface. In the production of coatings, it is involved that the air on the surface of the pigment and filler particles is replaced by water, so that the pigment and filler particles quickly enter the water phase, which is a short process. Dispersion refers to the mechanical process in which pigment particles are free from each other. In the production of paints, it means that the pigment and filler particles after entering the water phase system exist stably in the form of small particles in the water phase and are evenly distributed without re-aggregation. This is a long-term process. The combination of the two can play a synergistic role, so that the pigment particles can be stably dispersed in the paint in a more delicate form. This can improve the efficiency of grinding and dispersion, shorten the grinding time in the production process, and improve the coloring degree and hiding power of the pigment particles, which have a direct impact on the transparency, viscosity, fluidity, mechanical strength, stability, etc. of the coating. .
Second, the molecular structure of the wetting agent and dispersing agent are also different. The molecular weight of the wetting agent is small, and the small molecular weight makes it easier to migrate and more effectively reduce the surface tension of the pigment. The larger the molecular weight of the dispersant, the larger the molecular weight can provide better steric hindrance, prevent pigment flocculation, and make the dispersion system in a stable state.
Both dispersant and wetting agent are indispensable additives for coating products. The combined use of the two will produce better quality, more stable and better performance coatings.