The leveling property of coatings, also known as flattening properties or leveling properties, is an important indicator to measure the decorative performance of coatings. The national standard GB1750-89 (79) specifies the specific method for measuring leveling.
Brush or spray the paint on the base plate with a flat surface according to the "General Preparation Method of Paint Film". When brushing, start the stopwatch while the brush is opening the sample, and measure the time required for the brush marks to disappear and form a completely smooth paint film surface, expressed in minutes. Spraying is the same as the above method, and observe the time required for the painted surface to reach a uniform, smooth and wrinkle-free state.
Another empirical method is to adjust the paint sample to the construction viscosity, brush it on the sample plate with primer to make it smooth and even, then use a brush to wipe a brush mark in the middle of the coating film longitudinally, and observe how long it takes for the brush mark to disappear , the coating film returns to a smooth surface. Generally, the rating is based on the time it takes for the coating film to reach a uniform and smooth surface: the one that does not exceed 10 minutes is good; the one that is not uniform after 15 minutes is unqualified (non-decorative coatings do not need to do this requirement).
The evaluation of the leveling performance has a great relationship with the type and viscosity of the coating. Generally, the leveling performance of the coating with high viscosity is not as good as that of the low viscosity coating. With the development of science and technology, in recent years, many new leveling aids have been gradually applied, such as polyacrylate leveling agents, only need to add 0.2%~1.0% of the amount, can greatly improve the overall rheology and rheology of the coating film. Flatness.
The more effectively the brush mark or orange peel disappears, the smoother the coating surface is, that is, the better the decorative performance. Factors affecting the leveling of the coating can be improved by adding leveling aids to the coating product itself. The leveling performance of coatings is related to the composition and ratio of resin, pigment and solvent, and is also closely related to the construction method.
