二氧化碳基水性聚氨酯的制备及其合成工艺研究

A Study on Preparation and Synthesis Process of Carbon Dioxide Based Waterborne Polyurethane

本研究通过与传统的预聚体分散法及丙酮法的对比揭示了基于预聚体高温分散策略(ETD)的无溶剂法适用于二氧化碳基水性聚氨酯的合成。ETD策略在分散过程中的峰值黏度低于初始黏度,且微观相变形和摩擦较为有限,这明显区别于溶剂的加入通常带来降黏效果的传统观念,因此保证了预聚体的顺利分散。该方法制备得到的CO_(2)-WPU乳液试样性能与预聚体法性能相当。同时系统探讨了预聚物合成过程中异氰酸酯基团与羟基比值(NCO/OH)、内乳化剂含量、扩链过程中胺基与异氰酸酯基团比值(NH_(2)/NCO),以及扩链剂官能度等因素的影响,筛选出性能较为优异的CO_(2)-WPU乳液作为成膜树脂并应用于内墙涂料的制备,其性能达到了国标优等品的要求。

The elevated temperature dispersion strategy(ETD strategy)was proved a feasible approach for preparation of CO_(2) based waterborne polyurethane(CO_(2)-WPU).The peak viscosity of reactant in the dispersion process was lower than its initial viscosity in ETD strategy,and the microstructure deformation and friction were limited,which was significantly different from the conventional opinion that the addition of solvents usually led to reduction of viscosity and ensured the smooth dispersion of the prepolymer into water.In addition,the performance of CO_(2)-WPU prepared by ETD strategy was proved comparable to that of the prepolymer mixing process.Furthermore,the influence of isocyanate/hydroxyl ratio,amino/isocyanate ratio,and content of internal emulsifier was systematically discussed.Based on these studies,the CO_(2)-WPU with excellent performance was selected as the film-forming resin of interior wall coatings and showed excellent performance.