Solutions of Polymeric material applied which dries by solvent evaporation.
Examples: Shellac, Bitumen, Cellulose lacquers, Chlorinated rubber, Thermoplastic acrylics.
Dispersions of polymeric material in non-solvent is applied and forms film.
Examples: PVA paints
Solid polymeric material applied as a melt.
Examples: Ethyl cellulose, Bitumen
These dry quickly, usually at room temperature and so capital is not required for ovens or for heating them. Inter-coat adhesion is usually good because the solvent will soften the film underneath. Application is simple in that no measurement of catalyst is required. These products are single packs and have a long shelf life.
Non-convertible media however require powerful, usually expensive, and perhaps toxic, solvents to dissolve them. They require a lot of solvent to get to application viscosity, hence they produce thin films when the solvent evaporates as well as creating possible atmospheric pollution. Because thin films are produced, it is necessary to apply several coats.
Monday, October 25, 2010