Aliphatic polyisocyanate prepolymers and polyurethane resin coating compositions using the same

摘要

Two pack polyurethane coatings comprise a polyisocyanate prepolymer as a hardener and a polyol as a base resin. Coatings using aliphatic polyisocyanates have particularly good weather resistance in addition to wear resistance, chemical resistance, stain resistance etc and are of particular interest for automotive finishes. The aliphatic polyisocyanate is formed from the aliphatic diisocyanate and may be in the form of a biuret, adduct or as an isocyanurate. The latter is of particular interest, because of the properties obtained, but isocyanurate group-containing polyisocyanates lack compatibility with polyol compositions and can give unstable coatings.