1. Surface tension gradient —— liquid —— gas interface
The development of tension gradients on the surface of the inner and surface layers leads to turbulence
Elimination of the surface tension gradient is an important factor in obtaining a flat surface
2. Surface tension —— liquid —— solid interface
Lower surface tension than the substrate, so that the coating has a better wettability of the substrate
Lowering the surface tension of the coating reduces the attraction between surface molecules, thus promoting better flowability.
3. Factors affecting flow rate
The higher the viscosity, the slower the flow rate
The thicker the coating film, the faster the leveling
The higher the surface tension, the faster the leveling
Leveling agent is a common coating additives, it can promote the coating in the drying process to form a flat, smooth, uniform film. There are many types of leveling agents, and the type of leveling agent used varies from coating to coating. To improve the leveling of the coating, it is necessary to consider adjusting the formula and adding suitable leveling agents (or other additives) to make the coating have suitable surface tension and the ability to reduce the surface tension gradient.
In the actual construction process of paint, due to the poor leveling, brush marks when brushing, roll marks when rolling, orange peel when spraying, shrinkage, pinholes, flow hanging and other phenomena in the drying process, are called poor leveling, the generation of these phenomena reduce the decorative and protective function of the paint.
After the construction of paint, there is a flow and drying process, and then gradually form a flat, smooth and uniform coating film. Whether the coating film can achieve the flat and smooth characteristics is called leveling property. Shrinkage is one of the characteristic defects of the coating in the process of leveling and film formation. Therefore, leveling agent plays a role in the improvement of the leveling property of the coating.
Modified paraffin wax emulsion is used in exterior wall paint, it can improve the waterproof performance and anti-fouling performance.
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