Leveling
Leveling refers to the ability of the irregular and uneven surface in the coating film to flow into a flat and smooth surface after the coating is applied, and it is an important indicator for testing the construction performance of the coating. In CHINA , it is measured by brushing or spraying according to GB 1750-79 "Measurement of Leveling of Coatings". When using the brushing method, quickly brush the tested paint adjusted to the construction viscosity on the tinplate plate for 2~3 minutes vertically and then horizontally on the sample plate to make it smooth and even, and then brush one line longitudinally in the middle of the sample plate. There are brush marks but no bottom; when the brush leaves the sample, turn on the stopwatch to measure the time required for the brush marks to disappear and form a smooth coating film. The shorter the time, the better the leveling property. Generally, the coating film with good leveling property can be completely leveled within 10 minutes.
Sag resistance
Drooping refers to the phenomenon that the liquid paint is painted on the vertical surface. Under the influence of gravity, before the wet film is dry, part of the surface of the wet film falls downwards, forming the phenomenon . Coatings that are prone to sagging (or coatings with poor sag resistance) are not suitable for use in the spraying process . Sagging is caused by improper flow characteristics of the coating or by excessive coating thickness . The sagging speed of the paint is inversely proportional to its viscosity, so the paint adjusted to the appropriate viscosity is beneficial to avoid the occurrence of sagging. The method of measuring the sagging property of the paint is to apply , stand the test plate vertically, and observe the flow and fall of the wet film. The better the sagging.
