Water-Based Crosslinkers

Our QUICKSTAR® water based crosslinkers are aliphatic polycarbonate dendrimers with hydroxyl functionality as well as oxetane functionality. The hydroxyls enable these dendrimers to be water soluble. The oxetane functionality is like an epoxy (oxirane) functionality, though it is a 4 membered ring rather than a 3 membered ring. Oxetanes are ring strained, but are stable in alkaline conditions. They ring open at lower pH via an SN1 reaction to undergo addition of nucleophiles. Consequently, when a water based coating dries, and the amines evaporate to yield carboxylic acids, the carboxylates will add to the oxetanes to form an ester bond. The oxetanes can also undergo ring open polymerization.