Branched polyglycerols as performance additives for water-based flexographic printing inks

The aim of this work was to study the influence of polyglycerols on the selected properties of water-based printing ink and prints overprinted with water-based flexographic printing inks. Modified flexographic inks were laboratory printed on polyethylene plastic film. The impact of small amounts of various commercially available polyglycerols on printing ink colour was examined for the optical density of the full-tone area, colour values (CIELAB) and total colour difference ΔEab* and the gloss of the dried ink film. The dry and wet rub resistance of overprinted samples was investigated. In general, the addition of polyglycerols improved the wet and rub resistance of water-based flexographic printing ink with an acceptable total colour difference ΔEab*. The optical density and the gloss increased for those printing inks containing polyglycerols as compared to original printing ink. The small addition of glycerol ethoxylate to the water-based printing ink improved the wettability of the plastic film and the wet and dry rub resistance.