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Summary:
The environmental and health problems caused by inks containing volatile organic compounds (VOC) call for new solutions in printing ink chemistry and technology. One of the approaches may be the hot melt ink, which is ink solid at ambient temperature and liquid in the moment of printing. Such ink contains no volatile solvent to be trapped in ink film or to produce VOC. In this work, hot melt ink for the rotogravure printing process based on ethylene vinyl acetate (EVA) chemistry was formulated, analyzed for rheological properties, and printed on publication and packaging substrates. The original inks based on ethylvinylacetate and polyethylene (PE) chemistry was too viscous for rotogravure. The polymer matrix was mixed into the carnauba wax and then the rheology was tested again. Carnauba wax significantly decreased the viscosity of hot melt formulations. Draw-downs were made on publication (supercalendered grade A and lightweight coated) and packaging (SBS board) substrates and then the printability data was collected. The EVA/carnauba wax inks showed slightly higher optical density than PE inks. Print gloss, delta gloss and rub resistance properties were better on PE inks. Also mottling was lower at PE inks. SBS board exhibited highest print and delta gloss and lowest mottle index. The deinking experiments of hot melt ink and commercial toluene based ink were done. Slightly better optical properties were found on LWC paper deinked from hot melt ink than on that deinked from toluene-based ink.