초록 |
Trimerization of diisocyanate is an important step in polyurethane production since the trimer shows better properties than monomer. However, the cyclotrimerization also produces unwanted products, such as pentamer, heptamer and larger oligomers, which increase the viscosity of the product. To obtain the high selectivity of trimer, the activity of catalysts should be adjusted preventing further reaction. In this study, ammonium salts bearing a hydroxyl group are used as catalysts for the trimerization of 1, 6-hexamethylene diisocyanate (HDI). The hydroxyl group on the cation part of the catalyst interacts with anion part, so that the reactivity of catalyst can be controlled by making it hard for the cation to dissociate from the anion. |