Germ and bacterial protection with specialized automatic doors

In healthcare, cleanrooms, and other contamination-sensitive settings, surfaces must withstand frequent cleaning while actively resisting microbial growth. Extruded aluminum, thanks to its light weight and corrosion resistance, is often used in these spaces, and when anodized, it provides an excellent base for anti-microbial coatings.

But how well do these coatings actually perform after repeated exposure to harsh disinfectants and abrasion?

This article explores how anti-microbial coatings interact with anodized aluminum, how they’re tested for efficacy and durability, and what facility managers and specifiers should know to ensure long-term protection.

Applying Anti-microbial Coatings to Extruded Aluminum

Applying anti-microbial coatings to extruded aluminum with an anodize finish is increasingly common in cleanroom and healthcare environments due to aluminum's light weight and corrosion resistance. The anodize finish itself forms a robust oxide layer, improving durability and providing an ideal surface for specialized coatings.

Testing of Anti-Microbial Coatings on Anodized Aluminum

• ISO 22196 & JIS Z 2801: Standardized tests most frequently used to evaluate anti-microbial efficacy are ISO 22196 (Measurement of antibacterial activity on plastics and other non-porous surfaces) and JIS Z 2801. These methods measure the reduction of bacterial colonies after exposure to the coated surface compared to an untreated control.
• Surface Preparation: The aluminum is extruded, then anodized, before anti-microbial coatings are applied. The anodized oxide layer ensures better adhesion and uniform spreading of the coating.
• Durability and Chemical Resistance Testing: After application, panels are repeatedly exposed to common cleanroom cleaning agents (including alcohols, quaternary ammonium, hydrogen peroxide solutions, and chlorines) and subjected to mechanical abrasion simulating repeated cleaning cycles.
• Performance Verification: Efficacy is measured after multiple cleaning cycles to determine whether the anti-microbial action persists and the coating remains intact without significant degradation or discoloration.

Performance of Anti-Microbial Coatings on Anodized Aluminum

• Adhesion and Durability: Anti-microbial formulations generally adhere well to anodized aluminum due to surface porosity created during the anodizing process, resulting in sustained performance even after hundreds of cleaning cycles.
• Resistance to Cleaning Chemicals: Studies have shown that these coatings maintain antimicrobial efficacy and do not degrade or delaminate easily when regularly treated with typical cleanroom disinfectants such as isopropyl alcohol, hydrogen peroxide, and diluted bleach solutions.
• Efficacy: Typical test results demonstrate a log reduction (up to 99.9%) in microbial colonies (such as Staphylococcus aureus and Escherichia coli) after 24 hours of contact, even after repeated cleaning and abrasion.
• Aesthetic and Surface Integrity: Provided the anodized finish is high-quality and the coating is well-applied, both the anti-microbial properties and the surface appearance (color, gloss) can be preserved through repeated cleaning and use.
  
  

Additional Notes

• Anti-microbial coatings on anodized aluminum are commonly specified for environments requiring both strict hygiene and frequent cleaning, balancing performance and longevity.
• For specific product data or field test reports, it is recommended to request detailed technical documentation from the coating manufacturer or supplier.

Best Practices for Safe Cleaning

• Mild Detergents: Use neutral pH, non-abrasive, and residue-free detergents formulated for sensitive or coated surfaces.
• Diluted Solutions: For disinfectants, follow manufacturer recommendations regarding dilution and compatibility with surface finishes.
• Test First: Where possible, test any new chemical in a small, inconspicuous area before broad application.
• Read Manufacturer Guidelines: Always consult the anti-microbial finish supplier’s instructions for approved and prohibited cleaning agents.
  
  
  

Horton Automatics is committed to the health and safety and manufactures a selection of products that offer touchless activation to reduce microbial transmission. These hands-free touchless access solutions can be used in healthcare facilities, schools, government buildings, offices, and restrooms.

For an added layer of protection, Horton Automatics offers high performance antimicrobial finishes on all products.