Self-Cleaning Pre-Coated Aluminium Coils: Technical Details and Performance Data

1. Technical Definition and Process System

1.1 Substrate and Coating Composition

1.1.1 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.

• Thickness: from 0.15 to 2.0 mm.

1.1.2 Surface Pre-Treatment

Chromate or chromate-free passivation treatment is applied to enhance coating adhesion, meeting the 0-grade standard in the cross-hatch adhesion test.

2. Technical Principles and Coating Types

2.1 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. Well-treated PVDF coatings typically have a thickness of no less than 25 μm.

2.2 Nano-Self-Cleaning Coating

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

2.3 Self-Cleaning Coating Technology Roadmap

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3. Advantages of the Pre-Coating Process

3.1 Continuous Roll Production

• Utilises a roll coating - baking integrated production line with a speed of 50–100 m/min.

• Coating uniformity error is ≤5 μm.

• Efficiency is three times higher than single-coating of sheet materials.

3.2 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.

4. Core Features and Technical Advantages

4.1 Self-Cleaning Performance Metrics

4.1.1 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).

4.1.2 Reduced Maintenance Costs

• Conventional coatings require manual cleaning 2–3 times per year.

• Self-cleaning coatings can extend cleaning intervals to every 3–5 years.

• This results in over 60% savings in maintenance costs for high-rise buildings.

4.2 Weather Resistance and Protective Performance

4.2.1 UV Resistance

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

4.2.2 Corrosion Resistance

In salt spray tests (ASTM B117), no rusting occurs after 5,000 hours. Their service life is twice as long as conventional coatings in coastal areas.

4.3 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.