Presidential Green Chemistry Challenge: 2011 Designing Greener Chemicals Award
The Sherwin-Williams Company
Water-based Acrylic Alkyd Technology
Innovation and Benefits: Oil-based "alkyd" paints have high levels of volatile organic compounds (VOCs) that become air pollutants as the paint dries. Previous acrylic paints contained lower VOCs, but could not match the performance of alkyds. Sherwin-Williams developed water-based acrylic alkyd paints with low VOCs that can be made from recycled soda bottle plastic (PET), acrylics, and soybean oil. These paints combine the performance benefits of alkyds and low VOC content of acrylics. In 2010, Sherwin-Williams manufactured enough of these new paints to eliminate over 800,000 pounds of VOCs.
Summary of Technology: The high cost and uncertain availability of petroleum-based raw materials makes dependence on these materials unsustainable. Furthermore, the tightening of volatile organic compound (VOC) regulations by the Ozone Transport Commission (OTC) and the South Coast Air Quality Management District (SCAQMD) necessitates VOC-compliant waterborne coatings in place of solventborne coatings. Today, acrylic latex emulsions dominate the low-VOC waterborne coatings and alkyds dominate the solventborne coatings, but latex-based coatings have difficulty meeting all the performance and application properties of solventborne coatings.
To address this challenge, The Sherwin-Williams Company developed a novel, low-VOC, water-based acrylic alkyd technology based on sustainability principles. At the heart of this water-based acrylic alkyd technology is a low-VOC, alkyd–acrylic dispersion (LAAD). This polymer dispersion has PET (i.e., poly(ethylene terephthalate)) segments for rigidity, hardness, and hydrolytic resistance; it has acrylic functionality for improved dry times and durability; and it has soya functionality (from soybean oil) to promote film formation, gloss, flexibility, and cure. Sherwin-Williams designed this water-based acrylic alkyd technology to meet key performance attributes of solvent-based alkyds for architectural and industrial maintenance coatings applications, but with lower VOCs, without surfactants, and with excellent hydrolytic stability similar to that of latex paints. Sherwin-Williams water-based acrylic alkyd coatings bring together the best performance benefits of alkyd and acrylic paints, offering the application and finish of alkyds, including high gloss and excellent adhesion and moisture resistance, with the low VOC content, low odor and non-yellowing properties of acrylics.
Since the launch of their LAAD products, ProClassic Waterbased Acrylic Alkyd, ProMar 200 Waterbased Acrylic Alkyd, and ProIndustrial Waterborne Enamel, in 2010, Sherwin-Williams has eliminated the use of over 800,000 pounds of VOC solvents and other petroleum-based feedstocks.
Podcast on the technology:(MP3, 1 MB, 1:06 minutes), Narrator: Dr. Richard Engler, US EPA.
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