苯酚封端THEIC/异氰酸酯加成物反应的研究

STUDY ON THE BLOCKING REACTION OF THEIC/DIISOCYANATE ADDUCTS

研究了催化剂、溶剂、温度和不同加成物对反应的影响，实验结果表明，催化剂加快了封端反应，这种效果与催化剂本身结构有关。由两种催化剂构成的复合催化剂具有更好的催化作用，这可能与二者的协同作用有关，溶剂看来是参与了这个反应，溶剂的极性越强反应速率也越快，温度升高有利于反应的进行。当用ＴＨＥＩＣ／ＭＤＩ代替ＴＨＥＩＣ／ＴＤＩ时，封端反应更易进行，这是由于两种异氰酸酯的不同位阻效果所造成的。

Blocked THEIC/diisocyanate adduct is important ingredient for the synthesis of thermalstable PU paint. In this paper. blocking reaction of the adduct using phenol was studied. The effects of catalyst, solvent, temperature and different adduts on the reaction were examined. The results reveal that the presence of the catalyst indeed accelarats the reaction. Moreover, the effect closely associats with the catalyst structure. Hybrid catalyst exhibits higher effeciency. Synergic effect of two components in hybrid catalyst may account for this behavior. Solvent seems actively participate in the blocking reaction. The strongly the solvent polarity, the faster reaction would be. The reaction rate increases with the temperature raising. In addition, the blocking rate of THEIC/MDI is greater than of THEIC/TDI, this is ascribed to the hindrance to space.