Amine chemistries for isocyanate-based coatings

The inherent high reactivity and color instability of primary amines has limited their applicability in polyisocyanate-based coatings. However, recent developments in the use of modified amine functional coreactants in such formulations shows significant progress towards having two-component systems with excellent application and durability properties. The systems reviewed here use amine functional groups which are either blocked by addition of carbonyl compounds, or are of reduced reactivity through steric hindrance and intramolecular hydrogen bonding. The relative benefits and drawbacks of the various systems are detailed along with their applicability to high solids coatings.