VOC-reducing coating
VOC-reducing coating
Keywords: Georgia Institute of Technology, Coatings, Environmentally friendly
A new coating that is said to emit virtually no volatile organic compounds(VOCs) during application could possibly replace conventional solvent-based paints and anti-corrosion coatings in a wide range of uses. Developed by a research team at the Georgia Institute of Technology (Atlanta, Georgia), the patented ultra low VOC coating would meet new environmental regulations expected to severely limit VOC emissions from paints and other coatings.
"The potential applications are enormous", says Robert E. Schwerzel, a principal research scientist at Georgia Tech. "These coatings could, in principle, replace many of the solvent-based paints, enamels and varnishes that currently are used to coat everything from stoves and refrigerators to aircraft".
In addition to the coating's environmental attractiveness, the process used to produce it is believed to offer formulators a high degree of flexibility in selecting the resulting properties of the coating.
"We have developed a system for applying coatings that can be tuned for a whole group of different properties", says Charles Eckert, professor in Georgia Tech's School of Chemical Engineering. "We believe we will be able to adapt this to a variety of applications, each with different needs and different constraints".
Conventional polyester coatings are cross-linked and cured in a process that involves removing a small volatile molecule and evaporating an organic solvent. The small molecule and solvent usually evaporate into the atmosphere, becoming pollutants. The new process, however, removes and captures small molecules during the manufacturing process and does not require a solvent.
"Our coating molecules are applied to a surface and, with light or heat and a suitable catalyst, rearranged to form a strong, durable coating without any need for solvents or any need for removal of the small molecules", Eckert explains."This leaves us with a virtually zero-VOC paint".
Using chemical processes, the researchers produce cyclic polyester oligomer molecules that are polymerised using an organo-tin or organo-titanate catalyst to form a material that can be either a powder or a liquid at room temperature. Once applied to a surface, the coating is cured using heat or ultraviolet light to rearrange the cyclic polymer to a linear and cross-linked structure.
"The properties of these molecules can be changed by altering not only the backbone of the polymer, but also the side groups of the polymer", says Eckert."We have been able to make structural changes and get virtually any melting point we would like".
So far, researchers have produced only a small quantity of the new coating. Scaling up the process to provide commercial quantities at a competitive cost poses the next challenge.
