Waterborne polyurethane coatings were prepared using polyhydroxyacrylate dispersion, polyisocyanate, and propylene glycol diacetate (PGDA). The rate of reaction between hydroxyl and NCO groups in film formation and curing processes was studied by FTIR. The influence of PGDA amount on film formation and curing was also studied. Results showed that PGDA content had a significant effect on the curing process. With less than 10% PGDA, the role of PGDA was more to assist diffusion of polyhydroxyacrylate and polyisocyanate resin droplets. This promoted the reaction between hydroxyl groups and NCO. With more than 10% PGDA, its effect as a solvent was more and it inhibited the reaction between hydroxyl and NCO groups. When the amount of PGDA was about 10%, the synergy between both the roles promoted the crosslinking and curing reactions. The extent of the curing reaction of NCO was more than 70% in 4 h, which was significantly higher, compared with that of about 30% without PGDA. The good applicability and appearance of the waterborne polyurethane coating prepared in this study were verified for the application to carbon fiber metro vehicles.

中文翻译：

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FTIR跟踪研究PGDA溶剂对两组分水性聚氨酯涂料成膜和固化过程的影响

使用聚羟基丙烯酸酯分散体，聚异氰酸酯和丙二醇二乙酸酯（PGDA）制备水性聚氨酯涂料。通过FTIR研究了羟基和NCO基团在成膜和固化过程中的反应速率。还研究了PGDA量对成膜和固化的影响。结果表明，PGDA含量对固化过程有重要影响。PGD​​A含量低于10％时，PGDA的作用更多，以帮助其分散聚羟基丙烯酸酯和聚异氰酸酯树脂液滴。这促进了羟基与NCO之间的反应。PGD​​A含量超过10％时，其作为溶剂的作用更大，并且抑制了羟基与NCO基团之间的反应。当PGDA的量为约10％时，两种作用之间的协同作用促进了交联和固化反应。NCO的固化反应程度在4小时内超过70％，与不使用PGDA的情况下约30％的固化反应程度相比，明显更高。验证了本研究中制备的水性聚氨酯涂料的良好适用性和外观，可用于碳纤维地铁车辆。