Unlike lacquer, shellac and varnish, which have been around for centuries, polyurethane is a product of 20th-century lab technology. In some ways, polyurethane is better than traditional film coating.
Roofing is a crucial component of all types of buildings. Metal roofs with sprayed-on PU (Polyurethane) foam insulation, or "PU roofs," have currently become more popular due to their insulation ...