The impact of gravure ink dispersion on color reproduction in the manufacture of packaging for the food industry

Gravure printing is the best at reproducing the tonal values of colour images due to the ability of printing plates to reproduce different ink layer thicknesses in highlights, midtones and shadows and to use percentage values of colour saturation in their production.The setting time for triad gravure inks is determined by the evaporation rate of the solvent, its amount in each specific colour gradation and the properties of the printed surfaces.This article examines the impact of the formulation composition, concentration and dispersion of pigments for triadic inks in the dispersion medium of water-soluble resins on the time and quality of ink fixation on prints, rheological and optical parameters of aqueous ink systems.The ultrasonic dispersion of pigments in aqueous solutions of water-soluble polymers, performed with Hielschers UP50H and UP100H, contributes to high-quality colour reproduction on prints.The speed and quality of this dispersion method is influenced by the formulation of the inks.A pigment concentration of 8-12% and a medium molecular weight water-soluble resin of 10-15% results in a minimum dispersion time -99% of the dispersed phase crystals reach a size of 200 nm in 5 minutes.Highly dispersed microheterogeneous ink systems obtained by ultrasonic dispersion of pigments are able to stably retain cavitation nanocavities, which impair ink flow into the printing elements on gravure printing plates, but contribute to an increase in the ink transfer coefficient to polymeric PPS.The uniform size of the gravure ink system, which has the lowest percentage of pigments of any existing printing ink, creates equivalent or even higher optical density on the prints in the appropriate gradations due to the tight packing of highly dispersed crystals in the ink layers fixed to the prints, while synthesising high-quality and design-appropriate colour tones.