Alcoa EcoClean coating for aluminum panels fights against air pollution
As the primary component of smog, nitrogen oxide (NOx) not only makes buildings dirty, but it also threatens the quality of the air we breathe. Alcoa Architectural Products has developed EcoClean technology – a special titanium dioxide coating for aluminum panels which counter smog and clean the panels from other organic materials such as diesel exhaust or sulphur oxides (SOx).
Alcoa combined science, application technology and decades of architectural experience to create a product that makes a positive impact on the environment. They began to develop the coating technology in 2006, committing a team of more than 50 scientists and engineers to create a way to apply titanium dioxide to painted aluminum using a coil-coating process that would deliver all the self-cleaning and air-cleaning benefits of titanium dioxide without attacking the painted surface itself.
EcoClean is made in a process that leverages HYDROTECT technology from TOTO to apply a titanium dioxide coating to the pre-painted aluminum surface of Reynobond. Electrons within the titanium dioxide are agitated by UV light, creating a higher state of energy. That excess energy transfers to oxygen and water molecules in the air to form free radicals, which attack any organic material on or near the EcoClean surface. These particles are then ready to be washed away with just the slightest bit of moisture, such as light rain or morning dew.
With EcoClean, the generated free radicals attack and break down the NOx in smog to a harmless nitrate. The result is a building that helps to clean the air while also protecting the building’s surface. According to people from Alcoa, 930 square meters (10,000 square feet) of Reynobond with EcoClean has the approximate air cleansing power of 80 trees. That’s enough cleaning power to offset the smog created by the pollution output of four cars every day.
When exposed to UV light, the coating makes the surface of the building super hydrophilic (in other words, attracting water), so rainwater and other moisture that hit the surface collapse flat instead of beading up. This allows the organic particles of dirt and grime to slide right off, creating a cleaner building, resulting in lower maintenance costs and a better image.
Post-application of titanium dioxide by hand roller or spray is a much more expensive option than the coil-coating method applied with EcoClean. The EcoClean coil-coating application technology is not only more economical but it is also compatible with paint and does not attack its components. It can be expected that the addition of a clear coat to any painted base coat surface will slightly change that surface’s appearance. The translucent EcoClean coating will affect color and gloss slightly compared to non-coated products with that same color.
The coating lowers the water consummation as well as usage of harmful chemicals used in detergents. Although the coating keeps the panels cleaner in both active and passive way, there is a question of longevity of these panels and potential wearing of titanium dioxide coating, which could result with titanium dioxide dust. Evidence showed that high concentrations of pigment-grade (powdered) and ultra-fine titanium dioxide dust cause respiratory tract cancer.