METHOD FOR BREAKING DOWN UREA COMPOUNDS

摘要

Provided is a method for breaking down polyurea without adding a hydrolysis promoter such as alkali to the by-product urea residue obtained when producing isocyanate, material which has only been treated as waste in the past. Reusable polyamine can be recovered and there is no problem with corrosion of the reaction apparatus. The urea compound is broken down by hydrolysis in carbon dioxide in the super-critical state or the sub-critical state. The pressure during hydrolysis is preferably from 5 to 10 MPa and the water/reaction vessel volume ratio is preferably from 10/100 to 30/100.