What Is Self-Cleaning Pre-Painted Aluminum Coil？

Self-cleaning pre-coated aluminium coils are a new type of building and industrial material featuring a special functional coating applied to the surface of aluminium alloy coils, endowing them with the ability to automatically clean stains. Through the photocatalytic or superhydrophobic properties of the coating, the frequency of manual cleaning is significantly reduced, making it particularly suitable for high-rise buildings, outdoor facilities, and other scenarios where maintenance is challenging.

Technical Definition and Process System

Substrate and Coating Composition

Substrate Selection:

Common grades: 1100 pure aluminium (lightweight), 3003 aluminium-manganese alloy (rust-resistant), 5052 aluminium-magnesium alloy (high-strength). Coil width typically ranges from 1000 to 1500 mm, with thicknesses from 0.15 to 2.0 mm.

Surface Pre-Treatment: Chromate or chromate-free passivation treatment is applied to enhance coating adhesion (0-grade standard in cross-hatch adhesion test).

Technical Principles and Coating Types

PVDF Coating: Polyvinylidene fluoride (PVDF) coating is one of the core technologies of self-cleaning aluminium coils. Its smooth surface and UV-resistant, corrosion-resistant properties reduce dust and pollutant adhesion, enabling self-cleaning through rainwater rinsing or natural weathering.

Nano-Self-Cleaning Coating: Some products utilise nano-technology to enhance surface hydrophobicity and photocatalytic decomposition capabilities, further improving self-cleaning performance.

Self-cleaning coating technology roadmap:

Advantages of the pre-coating process

Continuous roll production: Utilises a roll coating - baking integrated production line (speed up to 50–100 m/min), with coating uniformity error ≤5 μm, and efficiency three times higher than single-coating of sheet materials.

Post-processing compatibility: After curing, the coating can withstand processing such as 180° bending and roll forming (e.g., forming into corrugated sheets or corrugated boards), and its self-cleaning function remains unaffected by deformation.

Core Features and Technical Advantages

1. Self-cleaning Performance Metrics

Stain Removal Efficiency:

Photocatalytic Type: For grease and exhaust fumes in urban air, the decomposition rate under 4 hours of light exposure is ≥95% (tested according to GB/T 23761);

Superhydrophobic Type: During simulated rainwater rinsing, mud residue is reduced by 80% compared to conventional coatings (ASTM D2486 test).

Reduced Maintenance Costs: Conventional coatings require manual cleaning 2–3 times per year, while self-cleaning coatings can extend cleaning intervals to every 3–5 years, resulting in over 60% savings in maintenance costs for high-rise buildings.

2. Weather Resistance and Protective Performance

UV resistance: Fluorocarbon self-cleaning coatings pass a 3,000-hour xenon lamp aging test (colour difference ΔE ≤ 3), suitable for tropical regions with high sunlight exposure.

Corrosion resistance: In salt spray tests (ASTM B117), no rusting occurs after 5,000 hours, with a service life twice as long as conventional coatings in coastal areas.

Comparison with the performance of ordinary pre-coated aluminium coils

Self-cleaning pre-coated aluminium coils, through innovations in coating technology, have upgraded building materials from ‘passive maintenance’ to ‘active self-cleaning.’ Especially in the context of rising labour costs and stricter environmental requirements, they have become the preferred solution for outdoor projects. From airport roofs to urban signage, their value lies not only in reducing cleaning frequency but also in extending material lifespan through long-term weather resistance, achieving ‘one-time investment, long-term peace of mind’ cost optimisation. For projects seeking low maintenance and high durability, self-cleaning aluminium coils are gradually replacing traditional coating materials, becoming a functional benchmark in modern architecture and industrial applications.