The main function of coatings is decoration and protection. Flow and leveling defects not only affect the appearance, but also damage the protection function. If the shrinkage hole is formed, the film thickness is not enough, and the formation of pinholes will lead to the discontinuity of the film, which will reduce the protectiveness of the film. This requires leveling agents to be added to the paint.
In the process of coating construction and film formation, some physical and chemical changes will take place. These changes and the nature of the coating itself will significantly affect the flow and level of the coating. If there are external pollutants, it may also lead to shrinkage, fish eye and other leveling defects.
After coating construction, new interfaces will appear, usually the liquid/solid interface between coating and substrate and the liquid/gas interface between coating and air. If the interfacial tension between the coating and the substrate is higher than the critical surface tension of the substrate, the coating can not be spread on the substrate, which will naturally lead to leveling defects such as fish eyes and shrinkage holes.
The properties of the paint itself, such as construction viscosity, drying time, etc., will also have a significant impact on the final leveling of the paint film. Excessive construction viscosity and short drying time usually result in poor surface leveling.
Therefore, it is necessary to add leveling agent to help the paint get a good leveling by adjusting some changes in the process of construction and film formation and the properties of the paint.
Yangzhou Lida Resin Co.,Ltd. Copyright(C) 2019
