Presidential Green Chemistry Challenge: 2013 Greener Reaction Conditions Award
The Dow Chemical Company
EVOQUETM Pre-Composite Polymer Technology
Summary of Technology: Titanium dioxide (TiO2) is added to most paint as the base white pigment that hides the color of the painted surface. TiO2 is employed due to its high refractive index and light scattering power. However, the high levels of TiO2 commonly found in paint formulations come at a cost to the paint formulator and the environment. TiO2 is often the most costly and energy-consuming component in a can of paint, and has the largest impact on the eco-profile of the finished paint formulation.
Dow Chemical has developed a pre-composite polymer called EVOQUETM that coats the TiO2 particles and improves their dispersion in the paint, allowing better hiding at lower pigment loading. The polymers bind to the pigment, improve the pigment interaction with the rest of the paint formulation, and result in a more even, contiguous dry paint layer. Once dry, paints formulated with EVOQUETM polymers provide better hiding, reducing the appearance of stains or colors on the painted surface and improved durability as a result of less pigment clumping.
EVOQUETM polymers are compatible with a wide range of paint formulations, including zero-VOC waterborne paints, reduce the need for rheology additives, and allow up to 20 percent lower TiO2 loading. A third-party validated Life Cycle Assessment (LCA) showed that TiO2 reductions allowed by EVOQUETM polymers in exterior house paint reduces the paint’s carbon footprint by over 22 percent, water consumption by 30 percent, NOx and SOx emissions by 24 percent, and the potential impact on water eutrophication (algae bloom) by 27 percent. Other benefits found in the LCA include a 30 percent reduction in potential chemical oxygen demand (COD) and a 35 percent reduction in non-methanic volatile compounds, two factors that degrade water quality and air quality. These benefits are in addition to the improved performance of the paint.