Reactive inkjet printing of polyurethanes

Reactive inkjet printing technology was used to create micron-scale polyurethane structures, such as dots, lines and pyramids. These structures were fabricated in situ and cured within five minutes by inkjet printing two separate inks successively from two separate print heads, with one ink containing isophorone diisocyanate, and the other consisting of an oligomer of poly(propylene glycol), a catalyst, and a cross-linking agent. The fast polymerization reaction that forms polyurethane at the surface opens a new route for rapid prototyping, as well as the use of inkjet printing as a technique for handling moisture-sensitive reactions. By the addition of fluorescent dyes to the polyol ink, confocal laser scanning fluorescence microscopy was used to investigate the miscibility behavior of both solutions on the substrate.