Recent developments in coating technology are designed to save time and money. Coating systems that cure faster, cool your roof and increase wind turbine efficiency are among the new entrants to the market. Intriguing advances in self-cleaning, self-healing and super-capacitor coatings are in the works.
Rapid finishing: Zinc coatings protect iron and steel from corrosion, but the standard application of a zinc primer, epoxy intermediate coat and polyurethane topcoat is time consuming. International Paint developed fast-curing coatings that are designed to reduce the total finishing time by allowing recoats in fewer than five hours. Interzinc 22 Series coatings are inorganic, zinc-rich ethyl silicate coatings. The two-pack, solvent-based primer is offered in four zinc dust content levels for maintenance, repair and new construction applications in a range of climates.
Energy savings: Two approaches to cool roof coatings provide energy savings. One reflects the sun’s energy, while the other provides thermal insulation. The first is an infrared reflective coating from PPG Industries. It has pearlescent pigments that reflect the sun’s heat. Duranar Vari-Cool, a PVDF fluoropolymer coating system based on PPG’s Ultra-Cool technology, is suited for aluminum and coated steel substrates in every weather environment. The polychromatic coating changes color based on the viewing angle and how light impinges on the surface. It’s a coil-formed Energy Star reflective roof product.
By comparison, a nanotechnology-based protective coating called Nansulate Crystal, developed by Industrial Nanotech, is designed to reduce the direct conduction of heat through sloped tile, slate and shingle roofs. Variants are available for flat and corrugated metal roofs. Nansulate is made with Hydro-NM-Oxide, a thin layer of nanomaterial with extremely low thermal conductivity that inhibits heat transfer. The clear, thin film coating also is designed to insulate against heat loss in cold weather and resist UV rays, moisture, mold, dust and dirt to prolong the roof’s service life.[pullquote]
Turbine efficiency: Wind power is one of the fastest-growing sources of renewable energy. Rotor blade coating systems aim to increase wind turbine efficiency. The new coating system from PPG Industries consists of a thin film, quick-drying HSP-7401 polyurethane primer and AUE-50000-series polyurethane topcoat. It uses a thinner build with as much as 60% less applied film than conventional polyurethane multicoat systems. This reduces labor and material costs and weight. Its high-adhesion, erosion-resistant, flexible properties are designed to increase blade protection and durability whether the turbine is in the desert or offshore.
Using a pore-free rotor blade surface in a thin film application reduces the need for manual finishing, consumes less paint and adds less weight to the blade. The Relius ProcessCoat from BASF is a pore-free groundcoat applied to the laminating mold as an inmold gelcoat. The company’s new Oldodur Blade Finish HS is a universally applicable topcoat for rotor blades that is designed to dry quickly and allow high film thickness. It can enhance resistance to erosion and weathering, making the coating suitable for offshore wind installations.
Promising material: A nanomaterial in development by Tel Aviv University researchers might someday form the basis for self-cleaning and super-capacitor coatings. By controlling peptide atoms and molecules, the researchers have been able to grow them in a form resembling small forests of grass. The peptide forests repel water, dust and dirt, introducing the possibility of a self-cleaning coating for windows and solar panels that reduce maintenance costs and increase solar panel efficiency. Additionally, the self-assembling peptide coating doubles as a super-capacitor with unusually high energy density, showing promise in enhancing battery storage capacity.
Interestingly, the nanomaterial was discovered while attempting to find a cure for Alzheimer’s disease. The lab has reportedly been approached to develop the coating technology commercially.
NASA’s vision: At the Kennedy Space Center’s Corrosion Technology Laboratory, researchers are developing a smart coating that heals itself. The coating’s walled microcapsules respond to the pH changes that occur when corrosion begins. The rise in pH causes the individual microcapsules to break and release the cargo of corrosion inhibitors stored inside. In addition, a color change is triggered, making the presence of corrosion easily identifiable so that maintenance personnel can take action.
The researchers are in the early stages of adding healing agents that will release automatically when scratches or other mechanical damage occur to the coating, producing a film to cover the exposed surface. The NASA laboratory is partnering with industry to commercialize the intelligent coatings.
E-mail Contributing Editor Sheila Kennedy, managing director of Additive Communications, at [email protected].