The metal, glass and brick building was originally constructed in 1980, and time and the elements have taken their toll on the painted metal surfaces. Oxidation had dulled the color and in some areas harsh weather had worn away the topcoat protection. Also, the metal surfaces were scratched by growing trees and shrubs. Two additions to the building over the years had aged differently, which created several color variations on its appearance.
Bayer chemists worked with coating manufacturer Tnemec Co. Inc., to formulate a paint that would deliver the look, quality and cost effectiveness desired. Analyses were performed on existing coatings in six different areas of the building, which was critical to formulate a product that would provide good adhesion between the old and new coatings and to minimize the contractor cost for surface preparation.
A test patch was used for one year to determine adhesion, weatherability, gloss and color retention, and corrosion resistance. All criteria were met, and the coating offers low VOCs and low odor.
The primer, Tnemec's Omnithane Series 550, a single- component, moisture-cured polyurethane, adheres to steel, rust and aged coatings. The top coat, Endura-Shield Series 1080, which uses a waterborne, air dry technology developed jointly by Bayer and Tnemec, provides abrasion resistance and color and gloss retention. The coating contains Desmodur N 3600 aliphatic polyacrylic dispersion and Bayhydrol A145, an aqueous hydroxyl-functional polyacrylic dispersion made by Bayer MaterialScience. The stripe detail on the building was coated with Tnemec's Endura-Shield 175, an aliphatic acrylic polyurethane.