Abstract
The invention provides a preparation method of polyurethane resin. The preparation method comprises the following steps: a liquid-phase polyamine compound enters and circulates in a continuous reaction system; solid-phase cyclic carbonate and a solid-phase catalyst inter into the continuous reaction system; a heterogeneous mixture is formed by mixing the solid-phase cyclic carbonate, the solid-phase catalyst and the liquid-phase polyamine compound; and the heterogeneous mixture is heated by microwave in the continuous reaction system for enabling the heterogeneous mixture to have reaction andgenerate polyurethane resin.