Functional Coatings for Aluminum Coil: Easy-Clean, Antibacterial and Thermal.

What does a functional coating add that a color coating does not?

A specific performance property the application asks for. A standard color coating protects the metal and decorates it. A functional coating adds something further: easier cleaning, limited bacterial growth, or lower solar absorption, each to the extent the test data supports. Orbit offers these as specialty capabilities, confirmed per substrate, color and volume through an RFQ.

The property sits on top of the base coating system and does not replace it. The base system still has to suit the exposure. Orbit's functional coatings page lists the options.

How does an easy-clean or anti-graffiti coating work?

It is meant to make the surface resist staining and release contaminants, with easier cleaning as the aim. In hydrophobic variants the surface repels water, so rain beads up and can carry some dirt away. Orbit's functional coatings page gives easier cleaning on a city facade as an example of where the property is wanted.

ASTM D6578 gives a way to judge graffiti resistance: a defined set of markings is removed with a defined set of cleaning agents. An easy-clean claim is a different property and needs its own stated method. Ask which markings, which cleaners and whether the specimen was weathered.

How does a silver-ion antibacterial coating work?

Silver ions are used as an antimicrobial. They are meant to disrupt bacterial cell function and inhibit reproduction on the coated surface, and any hygiene benefit is shown by test reports for your specification. Orbit's functional coatings page names healthcare, transit, hospitality and retail as high-contact settings where the property is wanted.

ISO 22196 is a method for evaluating antibacterial activity of antibacterial-treated plastics and other non-porous surfaces. Check the standard's scope against your product and surface. The standard excludes building materials, except where they are used in the same manner as treated articles, so ask which method a coated coil result was measured by. Read any claim as a property of the surface under defined test conditions.

How does a thermal coating work?

Orbit sells CS 10/100 as a thermal insulation coating. It uses NIR-reflective pigments and works by reflecting near-infrared solar radiation, which lowers solar heat absorption at the surface. A coil coating film is thin and is not an insulating layer in the building-envelope sense. Sunlight carries energy mostly in the visible and near-infrared ranges, so a pigment that reflects the near-infrared portion can keep the visible color. Such pigments can give a cooler surface than a standard pigment of the same visible color, depending on color and exposure.

A Lawrence Berkeley National Laboratory report on cool color roofing materials, published in 2006, describes complex inorganic pigments that are dark in color but highly reflective in the near-infrared, which is what lets a dark surface run cooler. Orbit names rolling shutters, facade and roofing as applications. The effect depends on color and exposure, so it is confirmed per specification, and this post gives no temperature figures. For the shutter case, see alloy and thermal coating options for rolling shutters.

Where does PVDF fit among the functional options?

Orbit lists PVDF alongside the functional coatings, for environments where resistance to chalking and color loss over long exterior service is the requirement. It adds durability, not a surface function such as cleanability or hygiene.

The PVDF facade specification post covers the specification side, including the 70:30 binder, panel consistency and coastal exposure.

How should a functional coating be specified?

• The property required, and the evidence you expect: a method, a standard or a test report
• The environment and exposure, including whether the surface will be weathered
• Substrate, alloy and gauge, and whether the coil will be formed after coating
• Color and finish
• Quantity and destination

Orbit confirms availability per substrate, color and volume through an RFQ, because these are specialty capabilities. We respond to RFQs within one business day.

What should not be assumed?

That a functional property is available in every color, substrate and volume. That it replaces the durability the base coating system provides. That a result measured on one surface carries over to another. And that a test result describes service performance, since each result describes a defined specimen under defined conditions.

Common questions

References

• ISO: ISO 22196, Measurement of antibacterial activity on plastics and other non-porous surfaces: ISO catalog entry for the antibacterial test method.
• Lawrence Berkeley National Laboratory: Cool Color Roofing Materials: Heat Island Group report from 2006 on near-infrared reflective pigments.