Coating compositions based on aldimines and polyisocyanates containing allophanate groups

The present Application is directed to coating compositions which have long pot lives, may be rapidly cured under ambient conditions to provide coatings with improved optical properties and contain as binder a) a polyisocyanate component containing i) 5 to 100 % by weight of a monoallophanate and ii) 0 to 95% by weight of another polyisocyanate adduct, and b) an aldimine based on the reaction product of a polyamine having 2 or more primary amino groups with an aldehyde corresponding to the formula: O=CHCH(R1)(R2> wherein R1 and R2 may be the same or different and represent optionally substituted hydrocarbon radicals, or R1 and R2 together with the beta -carbon atom form a cycloaliphatic or heterocyclic ring and c) optionally up to 5 weight percent, based on the weight of components a) and b), of a tin(IV) compound which is a catalyst for the reaction between isocyanate groups and hydroxyl groups, wherein components a) and b) are present in an amount sufficient to provide an equivalent ratio of isocyanate groups to aldimine groups of 0.5:1 to 20:1. Also claimed is the aldimine prepared from diamino dicyclohexyl methane and an aldehyde corresponding to the preceding formula.