Prepainted Marble Grain Steel for Wall Panel

The predominant application method for high-weather-resistance paints on color-coated metal sheets is the roller coating process. The core workflow consists of pretreatment → multiple coating passes → staged baking and curing. The specific steps are as follows: Substrate Pretreatment First, the aluminized-zinc or galvanized substrate undergoes surface degreasing and passivation treatments to remove surface oils and impurities, thereby enhancing coating adhesion. Following pretreatment, the substrate surface is ensured to possess uniform roughness and be free of any residual stains. Coating and Curing Process (Typically a "Three-Coat, Three-Bake" sequence, tailored for high-weather-resistance requirements) First Coat: Primer Roller Coating + First Bake A layer of high-adhesion, alkali-resistant primer is applied via roller coating, with the primer thickness controlled within the range of 5–8 μm. The substrate then enters a baking oven to cure at 180–220°C for 30–60 seconds, ensuring complete cross-linking of the primer and enhancing interlayer bonding strength. Second Coat: Topcoat/Color Coat/Printed Layer Roller Coating + Second Bake A high-weather-resistance topcoat—featuring specific colors or textures (for wood-grain textures, a printing process is completed prior to this step)—is applied via roller coating. The coating thickness is controlled within the range of 8–12 μm. The substrate re-enters the baking oven to cure at 200–240°C, allowing the topcoat to cure fully...