| abstract |
A heavy-duty anticorrosive coating is formed on a steel article by subjecting all or a part of the surface to a pretreatment and then forming a polyurethane coating thereon which is formed by reacting a mixture comprising as the main components, (a) a polyol having the main chain composed solely of carbon atoms and hydrogen atoms and containing at least two hydroxyl groups in the molecule and (b) an organic polyisocyanate compound, and an optional organic compound capable of reacting with the polyisocyanate compound (b). Preferably, the polyurethane-forming mixture is composed of (a) the polyol, (b) the polyisocyanate compound, (c) an optional polyol, other than the polyol (a), having a hydroxyl value not larger than 120 mg KOH/g, (d) an optional compound having at least two hydroxyl groups and/or amino groups in the molecule and having a hydroxyl value or amine value larger than 120 mg/KOH/g, and optional catalyst, extender, plasticizer and/or hygroscopic compound. |