What effect does the particle size of barium sulfate have on coatings?

Barium sulfate, as an inorganic pigment, is widely used in the coating industry. It exhibits excellent reflective properties in the wavelength range of 300-400 microns, can effectively prevent the paint film from being damaged by light aging, and is an efficient white matte stabilizer. Its unique needle-like crystal structure gives it excellent flat properties and can enhance the leveling of the coating.

In addition, the low oil absorption and high filling content of barium sulfate make it an effective means to control the cost of coatings. Among body pigments, barium sulfate occupies a dominant position, accounting for up to 70%, among which precipitated barium sulfate plays a vital role in coatings.

The particle size of precipitated barium sulfate has a multi-faceted effect on the performance of coatings:

Hiding power: Precipitated barium sulfate with a smaller particle size has a larger specific surface area and a stronger ability to scatter light, so it has a stronger hiding power. In contrast, precipitated barium sulfate with a larger particle size has a weaker ability to scatter light and a lower hiding power. It is necessary to increase the amount of addition to achieve the same hiding effect, but this may affect other coating properties. Gloss: Precipitated barium sulfate with a smaller particle size is more evenly dispersed in the coating, making the coating surface smoother and smoother, thereby improving the gloss. Precipitated barium sulfate with larger particle size tends to form agglomerates, resulting in an uneven coating surface and reduced gloss. Stability: Precipitated barium sulfate with small particle size and good dispersion can better blend with the coating system, reduce precipitation and stratification during storage, and maintain the stability of the coating.

Leveling: Precipitated barium sulfate with small particle size and good dispersion can improve the leveling of the coating and make the coating surface smoother. In coatings with high requirements for leveling, using precipitated barium sulfate with small particle size can achieve better coating effects. Therefore, when choosing precipitated barium sulfate, it is necessary to select products with appropriate particle size according to the coating formula and specific needs.