Abstract: Several environmental friendly catalysts have been used in the preparation of 2K waterborne polyurethane. The influence of various catalysts on reaction of water with -NCO and -OH groups and coatings performance was investigated by FT-IR and electrochemical polarization curves. It was found that organic bismuth/zinc composite catalyst shows the best performance from the result of FT-IR. The reaction kinetics of organic bismuth/zinc composite catalyst in 2K waterborne polyurethane has been studied by NCO titration method. The results further revealed that the existence of organic bismuth/zine composite can efficiently reduce the activation energy of the reaction between -NCO and -OH, accelerate the crosslinking and improve corrosion resistance property. A reasonable coating pot life and tack-free time can be achieved at the presence of 0. 25% organic bismuth/zinc composite catalyst。

Key words: waterborne polyurethane, 2K coatings, organic bismuth/zinc composite catalyst

摘要： 用几种环境友好的催化剂制备双组分水性聚氨酯涂料。用红外光谱(FT-IR)比较了不同催化剂对涂膜中—NCO和—OH及水反应的影响，并通过涂膜的电化学极化曲线和涂膜性能的变化筛选出了在本体系中有较强催化作用的有机铋/锌复合催化剂;采用—NCO滴定法对有机铋/锌复合催化剂在水性双组分聚氨酯体系中的动力学进行了研究。结果表明:有机铋/锌复合催化剂能有效地降低—NCO与—OH反应的活化能，促进涂膜交联，增强涂膜的耐蚀性，其用量约0.25%时有较好的适用期和表干时间。

关键词: 水性聚氨酯, 双组分涂料, 有机铋/锌催化剂