Since the aromatic isocyanurate structure produced by trimerization of aromatic isocyanates has been known to improve polyurethanes or coating materials in various properties such as enhanced thermal resistance, flame retardation, chemical resistance, and film-forming characteristics, a number of catalysts for isocyanate trimerization have been reported previously. For example, various metal salts of carboxylic acids, l tertiary amines, 2 metal ...
