水性丙烯酸树脂/HDI缩二脲复混物的制备及表征

Preparation and Characterization of Mixture of Waterborne Acrylic Resin and HDI Biuret

将水性丙烯酸树脂和HD I缩二脲混合后,加水稀释,制备了水性双组份聚氨酯(2K-WPU).研究了加水稀释过程中复混物粘度的变化和HD I缩二脲加入方式对2K-WPU性能的影响,并用粒径分布仪、透射电镜(TEM)和红外光谱(FTIR)对2K-WPU的性能进行了表征.结果表明:复混物在固含量为45%(质量分数)左右发生相转变;HD I缩二脲在水性丙烯酸树脂相转变点前加入,能被稳定分散于水中.从TEM分析结果来看,2K-WPU乳液粒呈核-壳结构,HD I缩二脲被水性丙烯酸酯包裹而分散于水中.添加HD I缩二脲后,2K-WPU乳液比相应的丙烯酸乳液粒径更大,粒径分布变窄;而添加HD I三聚体的2K-WPU乳液不但粒径大,而且呈双峰分布.FTIR结果证明了水性丙烯酸酯-HD I缩二脲之间的固化反应在12 h内就已完成.

A kind of two-component waterborne polyurethane （2K-WPU） was prepared by mixing HDI biuret and water-soluble acrylic resin, a dilution with water being followed. The influences of the mixture viscosity and the way of adding HDI biuret during the dilution on the properties of 2K-WPU, which was then characterized by particle size-testing instrument, TEM and FTIR, were also investigated. The results indicate that： （ 1 ） the phase inversion of 2K-WPU occurs at a solid content of the mixture of 45% （mass fraction） , （2） if added before the phase inversion point of waterborne acrylic resin, HDI biuret will disperses in water, achieving a stable 2K-WPU emulsion. （3） according to the TEM results, 2K-WPU particles possess the core-shell structure, in which HDI biuret is encapsulated by waterborne acrylic resin, （4） the 2K-WPU emulsion with HDI biuret is of larger particle size and narrower particle distribution than the acrylic resin emulsion, while the 2K-WPU emulsion with HDI isocyanurate trimer possesses not only a larger particle size but also a double-peak particle distribution, and （5） according to the FTIR results, the curing reaction between HDI biuret and waterborne acrylic resin completes in 12h.