PURIFICATION OF HIGH-MELTING AND HIGH-BOILING ISOCYANATES

摘要

PROBLEM TO BE SOLVED: To provide a process for purifying polyisocyanates with high-melting and high-boiling points safely and stably in high yield. SOLUTION: The polyisocyanates are heated at a temperature that the polyisocyanates are thermally not decomposed, and are distilled out under a reduced pressure in a short time while the loss of the fraction may not be caused yet.