| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for producing a urethodione group-containing polyisocyanate, which facilitates the control of a urethodione-forming reaction, the control of the reaction product composition and post treatments after the reaction. SOLUTION: This method for producing the urethodione group-containing polyisocyanate, characterized by converting an isocyanate group-containing compound derived from an organic diisocyanate into a uretedione compound in the presence of a urethodione-forming catalyst in a supercritical inert gas, and then charging and discharging an inert gas into the reaction system in a state maintaining the supercritical atmosphere to remove the free organic diisocyanate. The inert gas is preferably carbon dioxide, and the organic diisocyanate is preferably hexamethylene diisocyanate.</p> |
