Richard George Coogan

Post-crosslinking of water-borne urethanes

Abstract Water-borne polyurethanes are used as coatings because of their high performance. Polyurethanes deliver excellent abrasion resistance, tensile strength, impact strength and good low temperature flexibility. Due to process considerations, most water-borne urethane dispersions are linear thermoplastic polymers which can only contain low levels of pre-crosslinking. To improve chemical resistance, urethane dispersions can be post-crosslinked during or after film formation by a variety of crosslinkers. This paper will review the effects on coating properties after crosslinking with melamine, aziridine, epoxy silane, carbodiimide or water-dispersed isocyanate.