Synthesis of ADI/HDI hybrid isocyanurate and its application in polyurethane coating

Hybrid isocyanurate was prepared by solvent-free trimerization of hexamethylene diisocyanate (HDI) and bis(isocyanatomethyl) cyclohexane (ADI), and characterized by gel permeation chromatography (GPC), gas chromatography (GC), nuclear magnetic resonance (NMR), and electrospray ionization mass spectrometry (ESI–MS). The results showed that ADI/HDI hybrid isocyanurate could be prepared with 2-hydroxypropyl-trimethyl-azanium catalyst at reaction temperatures between 50°C and 70°C. Both the GC and 1 H NMR analyses identified a favorable linear relationship between the feed ratio of the starting monomers and the amount of each individual isocyanate incorporated into the oligomer (reaction ratio). Compared to coatings prepared from the mixture of ADI isocyanurate and HDI isocyanurate, the coatings from ADI/HDI hybrid isocyanurate possess higher distinctness of image.