have access to only a few VOC-exempt cleaning solvents. Today, few users substitute cleaning solvents to achieve exemption from regulations affecting VOC management.
94 The state of this work does not yet support specific and unique regulation in the U.S. 93 Environmental regulatory agencies in other countries and continents share that interest. EPA maintains a strong interest in modeling the interaction of emissions of chemicals with air currents-the precursors of smog. They are: release of reactive (with UV light) VOC chemicals release of oxides of nitrogen from combustion processes reaction of the two and other species and air currents in the troposphere which control the concentration of reactants and products. At least four factors dominate minimization of smog formation. Smog is formed by a complex and not completely understood reaction scheme (see Section 11.2). All these applications emit VOCs which react in the troposphere to produce atmospheric smog. Solvent cleaning shares a situation with a host of other applications such as the baking of bread, driving of automobiles, painting of surfaces, and storage of fuels. Innovation in modeling the atmospheric reactions which lead to formation of smog would strongly affect those doing solvent cleaning work. Durkee, in Developments in Surface Contamination and Cleaning (Second Edition), 2008 11.8.3.3 Regulatory Innovation Degreasing alone does not generally clean the substrate well enough to permit chemical surface alteration. Substrates can be wiped or sprayed with degreasing solvents, or they can be immersed in an agitated solution for about five minutes. Solvents such as methyl ethyl ketone, toluene, acetone, isopropyl alcohol, trichloroethylene, and perchloroethylene can be used. A range of solvents are available depending upon the scale of the cleaning operation, environmental control facilities available, and the expected type of contamination. The length of time required for solvent evaporation will vary according to solvent. A saturated cloth will not pick up debris particles from the substrate. Porous surfaces should be wiped with a lint-free cloth moistened with solvent the cloth should not be reused.
Solvent cleaning should both precede and follow abrasive treatments. Abrading surfaces coated with oil or grease drives the contaminants further into the parts, and chemical alteration of the surface is ineffective in the presence of contaminants. Solvent cleaning removes release agents, such as silicone that may coat the part during molding, and any machine oil transferred to the part.
Solvent cleaning is generally the first surface preparation method applied to the parts. In Handbook of Plastics Joining (Second Edition), 2009 17.7.2.1 Solvent Cleaning and Degreasing
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