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Six factors affecting the color difference of color-coated boards

Update:14 Jan 2021
Summary:

Color-coated panels have been widely used in the constr […]

Color-coated panels have been widely used in the construction industry, but sometimes the color difference of color-coated panels will reduce the user’s usage and cause losses to the manufacturer. Let’s take a look at the six factors that affect the chromatic aberration of color-coated panels. factor.

Color coated board
The factors that affect the color difference of color-coated boards are: paint, substrate, chemical coating treatment, film thickness, PMT and cooling water. Specifically:
1. Paint
Due to the uneven mixing of the paint or the large difference in the viscosity of the paint in different barrels, the paint extends from the side of the feed port to the direction of the return port in the tray, and a color band appears. In addition, changing the paint color, especially the two colors with large color contrast, will cause color difference due to improper cleaning.
2. Substrate
The difference in the size of the spangles on the substrate will also affect the chromatic aberration. Many small pits of different sizes will be formed at the grain boundaries, which will affect the chromatic aberration of the board. The color difference is particularly obvious for light colors, and it is best to use spangle-free or small-spangle substrates.
3. Chemical coating treatment
Improper chemical coating process will cause the chemical coating film to be too thick, and the board temperature will be insufficient after drying. If the roller body of the coating roller is damaged, yellow spots will be formed after drying, causing color difference of the color coating plate, especially the light color.
Fourth, film thickness
The film thickness stability has a greater influence on the color difference of the color-coated board. The film thickness adjustment methods mainly include: paint viscosity, adjusting the gap between the adhesive roller and the coating roller of the roller coater, changing the speed of the coating roller and the adhesive roller, adjusting the coating roller and the strip support roller Pressure and so on.
Five, PMT
PMT indicates the peak temperature of the strip when the coating is cured intact. The stability of PMT has a greater influence on the chromatic aberration of color-coated boards. Strip steel specification changes will cause PMT changes, local high or low temperatures will affect PMT changes, uneven substrate thickness will cause PMT changes, and seasonal changes in furnace temperature changes will also cause PMT changes.
Six, cooling water
Atomized cooling, the cooling water is not replaced in time. When the volatiles of the organic solvent in the furnace gas are cold and condensed, the cooling water is brought to the surface of the board and squeezed by the squeezing roller, causing color difference on the surface of the board. In production, the cooling water should be properly kept overflowing, so that the condensed volatiles should overflow and be removed in time to avoid causing color difference on the board surface.