Ionic liquids as performance additives for water-based printing inks

For the first time, the use of ionic liquids as additives for printing inks in order to improve the wettability of the printing base by the ink is presented. The aim of this work was to study the influence of ionic liquids on the selected properties of water-based printing ink and the prints. The contact angles of the printing inks on the printing base were measured. Modified flexographic inks were laboratory printed on polypropylene plastic film. The impact of small amounts of various ionic liquids on printing ink colour was examined in terms of the optical density of the full-tone area, the colour parameters (L*, a*, b*, CIE), the total colour difference, and the gloss of the dried ink film. The influence of ionic liquids on the ink contact angle, the optical density, and the L* a* b* coordinates is discussed. In general, the investigated ionic liquids improve the wettability of water-based flexographic printing ink, with an acceptable total colour difference. The optical density is increased for printing inks containing ionic liquids in comparison with the original flexographic printing ink, Process.