These inks consist of colorants, which may be pigments and soluble dyes along with a binder and various solvents.
Both solvent-based and water-based inks commonly contain various types of alcohol as the primary solvent or drier. Alcohol rapidly dries through evaporation and contributes to VOC emissions. The inks may also contain glycol ether and/or ammonia which facilitates drying.
Water-based flexography inks dry through evaporation and absorption on paper. This evaporation requires a greater amount of energy to dry the ink. Coated papers may be used to control the absorption through the paper. Due to the speed of the presses and volume of inks consumed daily, a pollution control system may be necessary — especially if the printer is using solvent-based inks. If the product allows, the printer may avoid pollution control equipment if they convert to water-based inks or U.V.-curable inks.
The cost of pollution control equipment for a small flexography or gravure printer will cost approximately $400,000 (1998 estimate) for the equipment and approximately $50,000 for testing and certification. The price increases as the size and/or volume of the operation increases.
U.V. flexography inks are commonly used for topcoats and lacquers and are responsible for improving image quality for flexographic printing. The use of U.V.-curable colored inks is rising within the flexographic printing industry, but product concerns and equipment investment are notable obstacles. It's also worth noting that water-based or U.V.-curable inks may not be an option for some printers due to the substrate being printed or design.