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利用甲苯二异氰酸酯(TDI)、三羟甲基丙烷(TMP)与二羟甲基丙酸(DMPA)反应,三乙胺(TEA)中和成盐及甲乙酮肟(MEKO)封端反应后,制得一种水分散性封闭多异氰酸酯(WBI)。研究了封闭时间对封闭率的影响,封闭顺序对反应的影响。采用FT-IR、TGA、DSC研究了其解封温度。实验结果表明,甲乙酮肟封闭反应的较好条件为:摩尔比n(MEKO)∶n(-NCO)为1.1～1.2;反应温度为70℃;反应时间3.0h,可实现较完全的封闭,其解封温度为70～128.8℃。作为涂料固化剂可明显改善漆膜性能。
(TDI), the reaction of trimethylolpropane (TMP) with dimethylolpropionic acid (DMPA), the neutralization of triethylamine (TEA) and the end-capping reaction of MEKO A water-dispersible blocked polyisocyanate (WBI) was obtained. The effect of blocking time on the blocking rate and the effect of blocking sequence on the reaction were studied. The unsealing temperature was studied by FT-IR, TGA and DSC. The experimental results showed that the better conditions for the reaction of methyl ethyl ketoxime to block the reaction were as follows: the mole ratio n (MEKO): n (-NCO) was 1.1-1.2; the reaction temperature was 70 ℃; the reaction time was 3.0h, Unsealing temperature is 70 ~ 128.8 ℃. As a coating curing agent can significantly improve the film performance.