Coil Materials (Color Steel/Aluminum Coil/Appliance Panel/Curtain Wall Panel)

1. Typical Procurement Scenarios

Core applications: building corrugated steel sheets/sandwich panels, curtain wall aluminum panels, home appliance panels, security door panels, integrated ceilings, photovoltaic back panels.

Core requirements: High-speed production line compatibility, thin coating for high efficiency, high flexibility and bend resistance, environmentally friendly with zero VOCs, and meets weather resistance/corrosion resistance standards.

2. Industry Pain Points

1. The production line speed is high (30–120 m/min), while the conventional powder curing speed is slow and cannot be adapted to the production line rhythm, which easily leads to powder accumulation and poor leveling.

2. The roll material needs to be wound, bent, and stamped in the subsequent process. Ordinary coatings are prone to cracking and peeling, and the T-bend index does not meet the standards, resulting in the scrap of the finished product.

3. Thin powder coatings (30–50 μm) are prone to insufficient hiding power and poor leveling, which affects the appearance quality.

4. Traditional liquid color coating has high VOC emissions, faces great pressure to comply with environmental protection regulations, and has low raw material utilization.

3. How to choose

1. Selection based on base material: Steel coil (indoor epoxy polyester blend type, outdoor pure polyester weather-resistant type); Aluminum coil (suitable for all speed ranges, pure polyester/fluorocarbon powder).

2. Select according to linear speed: use conventional fast-curing powder for medium speed (20-40m/min); use ultra-fast curing powder (200℃×30–60s) for high speed (60-100m/min).

3. Selection by function: General building materials (pure polyester thin coating powder), outdoor high weather resistance (ultra-weather resistant polyester), high-end home appliances (high leveling/scratch-resistant powder), high-end curtain walls (fluorocarbon powder).

4. Core indicators: film thickness 30–50μm, T-bend ≥2T, outdoor QUV aging ≥1000h, coastal aging ≥1500h, salt spray ≥800h.

4. Why choose this option?

1. Fast-curing thin-coating powder: Adaptable to high-speed production lines, shortens curing time, increases production capacity, reduces energy consumption, and solves the pain points of conventional powders such as powder piling and slow curing.

2. Highly flexible formula: Improves coating elongation to meet the needs of winding, bending, and stamping processes, avoids coating cracking, and reduces finished product scrap.

3. Substrate matching principle: Epoxy polyester for steel coils (strong corrosion resistance), pure polyester/fluorocarbon for aluminum coils (good weather resistance) to ensure that the coating adheres to the substrate and avoids separation.

4. Environmentally friendly with zero VOCs: It replaces traditional liquid color coating, eliminates waste gas treatment costs, and achieves a powder utilization rate of ≥95%, reducing raw material loss.

5. Process Recommendations

1. Pretreatment process: Steel coil (degreasing → phosphating → passivation → drying); Aluminum coil (degreasing → chromium-free passivation → drying); Key requirements: Surface roughness Ra 0.8-1.2μm, to improve adhesion.

2. Spraying process: Horizontal/vertical high-speed electrostatic rotary cup spraying and cloud spraying are adopted; the rotary cup speed is 8000-12000r/min, and the film thickness is precisely controlled at 30-50μm to avoid local unevenness.

3. Curing process: 220–240℃×30–60s (based on the peak temperature of the workpiece); using a combination of "infrared + hot air" heating to ensure rapid curing and uniform temperature.

4. Post-processing and inspection: After cooling to ≤40℃, wind up the film with a tension of ≤0.3MPa to avoid scratching the coating; mandatory inspection items (film thickness, T-bend, adhesion, QUV aging, salt spray test).

6. Recommended product mix

1. General applications for steel coils (indoor corrugated steel sheets, security doors): Epoxy polyester blended powder (colors: RAL9002 dove gray/RAL8001 ochre/RAL7022 black gray) + phosphating agent + high-speed curing agent, suitable for medium-speed production lines, balancing corrosion resistance and efficiency; dove gray is suitable for indoor ceilings, ochre for security doors, and black gray for industrial plants.

2. Outdoor aluminum coil applications (curtain wall aluminum panels, photovoltaic backsheets): Pure polyester weather-resistant thin-coated powder (color scheme: RAL6011 dark green/RAL5002 dark blue/RAL9010 pure white) + chromium-free passivating agent + high flexibility additives, meeting T-bend ≥2T, suitable for high-speed production lines, and meeting weather resistance standards; dark green is suitable for park curtain walls, dark blue is suitable for photovoltaic backsheets (dirt-resistant and heat-absorbing), and pure white is suitable for commercial complex curtain walls.

3. High-end roll-to-roll applications (landmark curtain walls, high-end appliance panels): Fluorocarbon powder (color schemes: RAL9018 Ivory White/RAL4001 Purple Red/RAL7000 Silver Gray) + special thin-coat leveling agent + adhesion promoter, zero VOC environmentally friendly, weather resistant for 20+ years, stain resistant and self-cleaning; Ivory White is suitable for high-end appliance panels, Purple Red is suitable for distinctive landmark curtain walls, and Silver Gray is suitable for modern office building curtain walls.