Sulfonic acid blocked metal catalysts for amine trigger urethane reactions

Abstract

The present invention is addressed a formulation curable in the presence of an amine and containing one or more of a polyol or polymercapto resin, a polyisocyanate cross-linking agent, optionally a organic vehicle, and a tin catalyst complex. The present invention comprises the catalyst complex being formed from a metal catalyst and a complexing sulfonic acid in an equivalent ratio of complexing sulfonic acid to metal catalyst of greater than 2:1. Such curable formulation may be compounded into a coating, an adhesive (including a structural adhesive), a caulk, a foundry binder, or the like. Besides having excellent shelf life, long periods of open time are experienced with the novel catalyzed formulation. However, upon exposure to an amine, the catalyst complex becomes activated and then is effective to catalyze the NCO--OH reaction or the NCO--SH reaction to effect cure of the formulation.

Dependencies are inferred from the claim text.