Development of Low-VOC Waterborne Coatings Derived from Polyurethane Dispersions based on Natural Oil Polyols using High Throughput Methods

By Jung Kwon Oh, Bedri Erdem, Jeff Anderson, Kumar Nanjundiah, Jeff Sweeney

Today’s coatings market exerts multiple pressures to success-fully develop and introduce new coating products. Improving the environmental profile of these new products is a large driver that often requires significantly different formulation strategies. These complex coating formulations offer an excellent opportunity to use the strengths of high-throughput (HT) research^1-3 to understand how interactions between coating components affect final properties.^4,5

Dow has invested considerable effort to develop HT capabilities as a means for developing coatings including waterborne architectural, 1K air-drying, and 2K reactive industrial coatings.⁶ Waterborne polyu ived from natural oil polyester polyols (NOPs) have been developed.^7,8 Coatings made from the NOP-based PUDs have good toughness, abrasion resistance, hydrolytic stability, and acid resistance. They also exhibit superior water uptake (less) relative to competitive PUDs, due to the hydrophobic nature of NOPs.^9,10

Due to emerging VOC regulations such as the South Coast Air Quality Management District (SCAQMD), Dow has recently focused on developing low-VOC PUD coatings for concrete and wood. The basic steps are to develop solvent-free NOP-PUDs that allow formulators to add good cosolvents to produce low-VOC PUD coatings with enhanced properties at a VOC level of <100 g/L.

To reach the goal, both the design of solvent-free NOP-PUDs with high performance and the formulation of them with good cosolvents are required. Good cosolvents enable the formation of crack-free films at ambient temperature and enhance end-user properties of PUD coatings at low VOC levels. In addition, solid understanding of mutual interactions between solvent-free PUD properties and solvents provides great flexibility in the design and development of low-VOC PUD coatings. This article describes how HT research (HTR) capabilities have been utilized for the development of low-VOC NOP-based PUD coatings for wood and concrete applications.

The HTR capabilities include statistically designed experiments, HT formulation, coating application, and characterization tools as well as informatics for data visualization, extraction, and modeling. This article begins with a brief introduction of these HTR capabilities and then concludes with use of these capabilities for development of low-VOC NOP-based PUDs.