An overview of water-based ink
Recently, water-based inks have been of more and more interest to the printing and ink industry, because of their environmental benefits. Compared with solvent-based inks, water-based inks have more complex formulations because of their higher surface tensions, lower drying speed, foaming problems, pH balance, and different rheological properties. The transition from solvent-based to waterborne inks has been facilitated by advances in both the chemistry and the printing technologies employed. With the new development in rheology modifiers and their increasing application in water-based gravure inks, a more complete investigation of their chemistry, thickening mechanism and effects on water-based gravure ink systems is necessary. This paper explores the significant effects of various rheology modifiers, including non-associative and associative thickeners, on the rheological properties of a water-based rotogravure ink system. Particular emphasis is given to thickening efficiency (viscosity profiles of each rheology modifier in a model system), pH stability, particle size, system compatibility, temperature stability, and printability on vinyl substrates. Wire-wound lab rods and a Moser Sheet-fed Gravure Proofing Machine were employed to produce printed samples for characterizing the performance of the formulated inks. The purpose of these investigations is to acquire a complete understanding of rheology modifiers' effects on the water- based ink system, as well as to help select appropriate rheology modifiers for water-based ink systems in order to achieve better print quality.