Effect of Low VOC Coalescents on Film Formation, Dirt Pick-up Resistance and Surfactant Leaching of Waterborne Paints

摘要

Low volatile organic compound (VOC) waterborne paints typically generate dry paint films with lower hardness and dirt pick-up resistance due to the usage of high boiling point coalescents. In this work, the effect of low VOC coalescents on latex film formation, hardness evolution, accelerated dirt pick-up resistance, and surfactant leaching of waterborne paints will be explored. Atomic force microscopy (AFM) images of styrene-acrylic and pure acrylic latexes containing 4 wt% of different coalescents show that low VOC coalescents generated films that were smoother and more coalesced than standard high VOC coalescent. A new low VOC coalescent generated semi-gloss paints with higher hardness evolution and better dirt pick-up resistance than commercial low VOC coalescents and similar to standard high VOC coalescent. Moreover, flat paints formulated with this low VOC coalescent dried at harsh conditions presented lower surfactant leaching in comparison to the ones formulated with standard high VOC coalescent. These results suggest that there is a correlation between surfactant leaching and film formation assessed through AFM.