The preparation of waterborne sodium bisulfite-blocked polyurethane curing agent

摘要

waterborne sodium bisulfite-blocked polyurethane was using polyether diols(N210), isophorone diisocyanate (IPDI) as the main material, sodium bisulfite as blocking agent, ethanol as the cosolvent. The effect of temperature and time of blocking reaction, alcohol than water were carefully studied. The best process parameter of blocking reaction:the temperature was 20°C; the reaction time was 45min; n(NaHSO_3):n(NCO)=1.1; alcohol than water=1.85; the deblocking temperature determined by DSC was about 76~130°C.