Study on Polyaryl Polymethylene Isocyanate Blocked by Diacetylmonoxime

Blocked polyisocyanate were synthesized with diacetylmonoxime as blocking agent.The influence of the molar ratio,reaction temperature and time of blocking reaction were discussed by experiment.The deblocking temperatures of blocked isocyanate were researched by the infrared spectra.The results showed that the optimum reaction condition was obtained when the mole ratio of the diacetylmonoxime to the polyisocyanates was 1.2,the reaction temperature was 60 ℃,and the reaction time was 3 h.The deblocking temperature was 120 ℃.