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Environment

Greener Reaction Conditions Award: Dow Chemical

Industry Giant Wins For Its Innovative Polymer-Based Technology That Reduces The Amount Of Titanium Dioxide Pigment Needed In Paint

by Stephen K. Ritter
December 13, 2013 | A version of this story appeared in Volume 91, Issue 50

This is a photo of the Dow team that worked on titanium dioxide performance in paint.
Credit: Dow Chemical
Dow’s team that created a polymer coating to improve titanium dioxide performance in paints: First row (left to right), Edwin Nungesser, Kebede Beshah, Melinda Keefe, Linda Adamson, Michele Heffner, Deborah Fradkin Shaw, Jacquelyn Rofe-Risner, Beth Cooper, Arlene Pratt, Stan Brownell, Wei Gao, and Shan Jiang; second row: Kenneth Lennon, David Fasano, David Kelly, Daniel Bors, Kathleen Auld, Laurel Rufe, Joy Gallagher, Yanli Gong, Laura Braccio, Thomas Bell, and Judith Varner; third row: James Bohling, Miroslav Janco, Philip Harsh, Bryan Ruzek, Morris Wills, Julie Mahaffey, Christopher Kozak, Yogesh Tiwary, and Qing Zhang.

Dow Chemical garnered the Greener Reaction Conditions Award for its Evoque precomposite polymer technology, which helps improve paint properties while using as much as 20% less titanium dioxide pigment. This win marks the ninth time that Dow has received a Presidential Green Chemistry Challenge Award during the program’s 18-year history—more than any other company.

TiO2 is added to paints as the base white pigment. The material is opaque and serves to hide the background color of the painted surface. It also helps prevent discoloring tannin from leaching through the underlying wood and rust stains bleeding through from painted-over nails, screws, and metal surfaces. But TiO2 is energy intensive to mine, process, and transport, typically making it the most costly ingredient that goes into a can of paint.

In a typical paint formulation, TiO2 particles can crowd together and become unevenly distributed, which decreases the pigment’s light-scattering power and thus its hiding efficiency. Instead of simply adding more TiO2 to compensate, Dow Coating Materials scientists took a different approach. They developed an acrylic-based copolymer coating that envelops TiO2 particles to better separate them, improving particle dispersion and light-scattering efficiency on the painted surface.

Evoque gives paint formulators options for designing different products: choosing to use less TiO2 to lower cost, using the same amount of TiO2 and improving performance, or choosing a combination of the two. In addition, an independent life-cycle analysis commissioned by the company documented that the polymer-TiO2 composite in exterior house paint reduces the paint’s carbon footprint by more than 22%, water consumption by 30%, and NOx and SOx emissions by 24%.

“Evoque was developed with the goal of driving gains in sustainability through more efficient raw material use coupled with increased paint performance,” says Keith Watson, global R&D director for Dow Coating Materials. “With the development and market acceptance of Evoque, we are driving innovation that is changing the way paint is made and how we expect paint to perform.”

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