Low-VOC Waterborne Coatings for Use in Industrial Maintenance Painting

By Leo J. Procopio, Gary R. Larson, William J. Rosano

Environmental regulations have put increasing pres­sure on all members of the coatings industry to develop and use coatings that have lower impact on our envi­ronment. Raw material suppliers are constantly working to develop new resins and additives that allow paint manufacturers to produce coatings with favorable health, safety, and environmental profiles. In addition, painting contractors and end-users such as homeown­ers and facility owners are constantly asking for higher performing products.

Those two desires are often diffi­cult to bring together in a new product, especially when it comes to lowering volatile organic compound (VOC) levels. Waterborne latex coatings are one technology which provides an opportunity to reduce VOC levels relative to traditional solventborne technologies.

However, technical challenges still exist, considering the low-VOC targets posed by many existing and pro­posed regulations. In particular, properties such as hardness, dirt pickup resistance, block and print resist­ance, and the ability to withstand freeze-thaw cycles, can be difficult to achieve.

Using latex polymers with lower glass transition temperatures is an obvious route to coatings that require less coalescing solvents and have lower VOC demands, but this seemingly simple solution also leads to many of the problems already mentioned.