The opportunity, one the EPA has offered 53 times before, is to use a chemical without the need to be concerned for compliance with volatile organic compound (VOC) regulations. The EPA's decisions in this regard are covered by the 1971 Clean Air Act (CAA), which addresses the issue of volatility. But in this case, volatility is not an issue; "reactivity" is the only issue. The EPA's decisions are based on the chemicals in question being exempted from VOC regulations, as these are nearly totally unreactive with sunlight in the atmosphere so that smog is not produced.
Past exemptions from VOC status have been extended to chemicals of limited interest to finishers: trifluoroethane (HFC-23), 1,1,1,2,3,3-hexafluoropropane (HFC-236 ea), and methyl formate (very toxic and highly flammable). This time, the decision was about two chemicals of potentially significant interest to finishers. The price of neither chemical promises "sticker shock."
One is propylene carbonate, an excellent solvent used in cosmetics, adhesive components, food packaging, plasticizers, synthetic fibers and polymers, and coatings.
The second is dimethyl carbonate, a highly effective solvent used in paints and coatings; it has significant miscibility with water so that it may also be used in waterborne paints and adhesives.
Of more interest to this author is that the latter has solubility and other properties that might make it a replacement for trichloroethylene in solvent cleaning operations. That topic will be covered in my column in a forthcoming issue of Metal Finishing.
Article by John B. Durkee, PhD, PE, and “Cleaning Times” columnist for Metal Finishing magazine.