University of Missouri-Rolla chemist Dr. Michael Van De Mark, director of the UMR Coatings Institute, received a Presidential Green Chemistry Award from the U.S. Environmental Protection Agency for his invention of an environmentally friendly latex paint additive that reduces volatile organic compound (VOC) emissions. The additive is marketed under the trademark Archer RC by Archer Daniels Midland (ADM). The award was presented Monday, June 20, at the National Academy of Sciences in Washington, D.C.
Latex paint makes up approximately 65 percent of all paint used in the U.S. and it contains two sources of volatile organic components. One component is a glycol that is used as an antifreeze and for wet edge retention; the other is a coalescing agent.
Van De Mark’s invention, a vegetable-oil derivative, replaces the volatile coalescent with one that doesn’t leave the film. “It doesn’t continuously plasticize the paint forever,” Van De Mark explains. “It air oxydizes and oligomerizes the additive, linking several coalescent aid molecules together to form a low-molecular weight polymer, and you get part of the hardness back. It softens the paint right away, but over a period of weeks, it regains most of its hardness.”
Latex resins are solid particles of plastic approximately one-tenth of a micron in diameter. Without a coalescent aid in the paint mixture to allow the drying particles to flow together to form a film, a hard-type resin will crack as it dries.
“With the coalescent aid, those little hard particles are softened and flow together, forming a film,” Van De Mark explains. “Without the coalescent aid, you can’t form a film.”
Traditional coalescing agents soften the paint, then evaporate away to return the paint’s hardness, releasing the solvent into the air, which adds to air pollution.
To create the derivative, Van De Mark took a simple glycol and reacted it with the unsaturated fat, the vegetable oil, which then formed a new coalescent aid. Unlike traditional chemicals like IBT filmer (a trade name of Dow), Texanol (a trade name of Eastman) and butoxy ethanol, Van De Mark’s product stays in the paint.
Van De Mark’s invention was licensed by Archer Daniels Midland and is currently marketed under the trademark Archer RC. The process works with any unsaturated oil derivative, but ADM chose to use sunflower oil.
Van De Mark first invented the additive 10 years ago while trying to find a use for Missouri plant-based oils, originally studying soybean oil derivatives with funding from the Missouri Soybean Merchandising Council.
The Presidential Green Chemistry Challenge was established in 1995 as part of the Reinventing Environmental Regulations Initiative to promote pollution prevention and industrial ecology through a new EPA Design for the Environment partnership with the chemical industry. EPA’s Office of Pollution Prevention and Toxics leads this voluntary partnership program.
In addition to Van De Mark, the award is shared by Dr. Paul Bloom and Dr. George Poppe from ADM; and Jeff Nelson of Stepan Co., who were responsible for implementing the UMR technology.