Why aliphatic spray polyurethane/polyurea elastomers?

Traditional spray polyurethane/polyurea elastomers are not light stable (re: weatherable) because they are based on aromatic polyisocyanates (typically methylene diphenyl di-isocyanate or MDI). There are many outdoor uses for thick film sprayable coatings including secondary containment, corrosion protection, and decorative applications. Weather resistance of spray polyurethane/polyurea elastomers was elusive until aromatic polyisocyanates were replaced by aliphatic polyisocyanates. Aliphatic polyisocyanates have a proven history of long term exterior weathering resistance in the automotive OEM, automotive repair, transportation, off-road vehicle and construction markets. Combining aliphatic polyisocyanates with the co-reactant technology used in non-light stable spray systems created a good compromise of weatherable performance and rapid application.