Inks and ink components

The main function of the printing process is to provide contrast and colour to the substrate. The ink must meet the requirements that depend on the printing process and the substrate, i.e., rheological properties, surface chemical properties and drying properties. Consequently the composition of inks varies widely. In addition, it should be user and environmentally friendly. As for food packages, toxicological and migration properties must be observed. 

The purpose of binders or resins is to bind the pigment to the substrate and to improve the general resistance of the print towards moisture or fat. They 

Most inks contain significant amounts of solvent for dissolving the resin and adjusting the ink viscosity. The kind of solvent used depends on the substrate and the end use of the print. Water as well as hydrocarbons are used, also ketones, esters and alcohols. For example ethanol and isopropanol are common in flexo printing. The solution of resin in a solvent is also called vehicle . 

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