Flexographic printing ink modified with hyperbranched polymers: Boltorn™ P500 and Boltorn™ P1000

The flexographic printing ink Urania® was modified with commercially available hyperbranched polymers, Boltorn™ P500 and Boltorn™ P1000. The surface tension of the printing inks was measured and the rheology behaviour of pure polymers and printing inks is presented. The obtained flow curves (shear stress versus shear rate) for printing inks exhibited pseudoplastic behaviour. Modified flexographic inks were laboratory printed on three different plastic films: PE, oPP and PET. The impact of a small amount of hyperbranched polymers on printing ink colour was examined by optical density, total colour difference ΔE (L∗, a∗, b∗, CIE) and the gloss of the print film. In general, the addition of hyperbranched polymers improved the colour properties of the overprinted sample and colour fastness to rubbing. The influence of hyperbranched polymers on the rheological properties, optical density and L∗, a∗, b∗ coordinates and colour fastness is discussed.

► The use of hyperbranched polymers as performance additives to printing inks is presented.
► The surface tension and rheology behaviour of the printing inks was measured.
► The influence of hyperbranched polymer on optical density, L*a*b* colour coordinates and colour fastness was observed.
► The small addition of P500 to the printing ink improved the print quality of overprinted plastic films.