The coatings used for color-coated coils typically consist of four components: resins (film-forming substances), pigments, solvents, and additives. Commonly used primers include epoxy, polyester, acrylic, and polyurethane; the specific choice is generally determined by the product's intended application, processing requirements, and compatibility with the topcoat. The typical film thickness of the primer ranges from 5 to 7 microns. Epoxy primers offer excellent adhesion and chemical resistance; polyester primers provide superior adhesion and flexibility; acrylic primers feature a low organic solvent content; and polyurethane primers excel in both chemical resistance and flexibility.
With advancements in technology, high-performance, eco-friendly powder-coated coils have emerged. These products utilize an electrostatic coating process in which polymeric powder coatings are sprayed onto the substrate surface and subsequently cured at high temperatures to form a highly dense coating layer. Color-coated coils produced via this process offer numerous advantages, including exceptional corrosion resistance (with acid and alkali resistance levels reaching 5 to 6 times that of traditional products), zero formaldehyde emissions, Class A2 fire resistance, and weather resistance that matches the service life of the building itself. Furthermore, the coating can be applied in a single pass to achieve a thickness of 35 to 200 microns, thereby simplifying production workflows for downstream industries such as home appliance manufacturing.