| abstract |
Disclosed is an activatable catalyst which is effective for the reaction of a hydroxyl compound and an isocyanate. Preferably, the catalyst is utilized in the cure of a coating composition of a polyol and a polyisocyanate. The activatable catalyst is activated in the presence of an amine activator or heat and comprises the reaction product of a metal catalyst selected from a tin catalyst, a bismuth catalyst, and mixtures thereof; and a molar excess of a complexing agent. The complexing agent is selected from a mercapto compound, a polyphenol characterized by being reactable with an isocyanate group in the presence of a tertiary amine activator, and mixtures thereof. A single polyol resin may bear both the complexing functionality and the activatable catalyst. Advantageusly, the polyol and polyisocyanate both are aliphatic. |