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Firstly, wetting, in terms of the dispersion of pigments, is actually divided into three steps.

The first step of wetting is actually a wetting step. The surface of the pigment is wetted, and it actually adsorbs a lot of air. Whether it is resin, solvent, water, or dispersant carrier, it is necessary to remove the air on the surface of the pigment through the wetting process. After being discharged, the dispersant can come into contact with the pigment and adsorb onto its surface. It is a wetting process.

The second process of wetting is the process of dispersion. The wetting process of dispersion relies on mechanical forces such as high-speed stirring, sanding, rolling, etc., to wet and fine the pigment particles.

The third process of wetting is a stable process. Wetting with process dispersants, after adsorption on the surface of pigments, wetting is achieved through steric hindrance or repulsion of charges, etc., and then the entire system becomes particles in a stable distribution state. So for the dispersion of pigments, wetting is actually quite important, especially for the dispersion of water-based pigments. Knowing that the surface tension of water is very high, this high surface tension has a relatively weak effect on the wetting of pigments. Therefore, most water-based coatings need to be added. The pigment wetting agent plays a role in wetting the pigment, wetting the air on the surface of the pigment and removing it.

Why do some water-based formulas add wetting agents while others do not?

The vast majority of water-based colorants actually require the addition of wetting agents, but for wetting, there are also some water-based formulations that do not require wetting agents. Divided into two aspects,

The first aspect of wetting is the use of dispersants, many of which actually have the function of wetting. Many dispersants, also known as wetting dispersants, have the function of wetting themselves.

The second water-based formula for wetting is water-soluble. It actually contains solvents inside, which act as wetting agents and effectively reduce surface tension and wetting. So when it comes to wetting, there may be some formulas that are not added.

Should solvent based coatings also be wetted with pigment wetting agents?

Normally, solvent based coatings have a relatively low surface tension of the solvent itself, which makes them effective in wetting pigments. So in most cases, solvent based coatings do not require the addition of pigment wetting agents. But there are some special features, such as adding wetting agents to improve its dispersion efficiency and initial wetting efficiency.

Its efficiency can also be improved, and a moderate amount can be added. In addition, wetting is sometimes done to improve the dispersibility of solvent based pigments such as high-speed carbon black, some matting powders, and silica, which are porous and difficult to disperse.

Sometimes, other methods are used, such as dissolving dispersants, base materials, and resins together, adding them together, stirring them evenly, wetting them, and letting them sit for one night before grinding the next day. It is found that the efficiency is greatly improved. In fact, it is through this kind of cleaning that the wetting function of the pigment is improved, the air on the surface of the pigment is wetted, and it is discharged, thereby enhancing its dispersion speed.