In the production and application of paints, wetting agents are indispensable functional additives. Their core function is to solve the interface problems between liquid coatings and solid substrates, as well as between pigment particles, and to optimize the performance of the paint. 
Firstly, during the pigment dispersion stage, the pigments in the paint are mostly solid particles, which tend to aggregate due to surface tension. Wetting agents can reduce the surface tension of the coating system and quickly penetrate into the gaps between pigment particles, replacing the air and impurities on the particle surfaces, allowing the pigments to be uniformly dispersed in the resin matrix. This process can prevent pigment precipitation and agglomeration, ensure uniform paint color, and reduce the grinding time, thereby improving production efficiency. 
Secondly, in the coating application stage, wetting agents can improve the adhesion of the paint to the substrate. When the paint is applied to metal, wood, plastic, etc., the wetting agent can reduce the contact angle between the paint and the substrate, allowing the paint to spread quickly and uniformly, avoiding defects such as pinholes, bubbles, and missed coating, and ensuring that the paint film completely covers the substrate surface. 
Furthermore, wetting agents can also enhance the final performance of the paint film. They can reduce the formation of bubbles during the drying process of the paint film, lower the surface roughness of the paint film, make the paint film smoother and more flat; at the same time, they can enhance the adhesion between the paint film and the substrate, improve the water resistance and weather resistance of the paint, and extend the service life of the coating. 
In summary, wetting agents play a role in key stages such as pigment dispersion, substrate wetting, and paint film optimization by regulating the interfacial tension. They are important additives that ensure the quality and application effect of paints.