The importance of using leveling agents in paint formulations

During the construction and film-forming process of coatings, some physical and chemical changes may occur, which, along with the properties of the coating itself, will significantly affect the flow and leveling of the coating.

After coating application, if the interfacial tension between the coating and the substrate is higher than the critical surface tension of the substrate, the coating cannot spread on the substrate, naturally resulting in leveling defects such as fish eyes and shrinkage cavities.

The evaporation of solvents during the drying process of paint film can cause temperature, density, and surface tension differences between the surface and interior of the paint film, which in turn lead to turbulent motion inside the paint film, forming the so-called Benard vortex. Benard vortex can cause the production of orange peel; In systems containing more than one pigment, if there is a certain difference in the mobility of pigment particles, Benard vortices are also likely to cause floating and blooming, and vertical surface construction can lead to silk lines.

During the drying process of the paint film, insoluble particles may sometimes be generated, which can lead to the formation of surface tension gradients and often result in the formation of shrinkage cavities in the paint film.

During the construction and film formation process of coatings, the presence of external pollutants may also cause leveling defects such as shrinkage cavities and fish eyes.

The coating itself, such as construction viscosity and drying time, can also have a significant impact on the final leveling of the paint film. Excessive construction viscosity and short drying time often result in poorly leveled surfaces.

Therefore, it is necessary to add leveling agents and adjust the properties of the coating during construction and film formation to help the coating achieve good leveling.