PRODUCTION OF SOLUTION CONTAINING AT LEAST ONE KIND OF ISOCYANATE

摘要

PROBLEM TO BE SOLVED: To obtain the subject solution which does not contain a noticable amount of coloration components at all and contain a relatively low amount of hydrolyzable chlorine by directly treating them with hydrogen at a relatively low temperature and pressure without additive temperature treatment and stress. SOLUTION: A solution containing at least one kind of isocyanate is phosgenated then treated with hydrogen before the perfect removal of the solvent. The treatment with hydrogen is carried out under the pressure of 0.5×10<5> -2.8×10<5> Pa at 70-150 deg.C in the phosgenation reagent. In a preferred embodiment, at least one of the isocyanate is an isocyanate in the group of diphenylmethane diisocyanates.