Rheological Properties of Heatset Inks

Viscoelastic and flow measurements were conducted on different heatset varnishes in order to clarify some of their peculiar rheological characteristics. A succinct characterization of the industrial varnishes studied, followed by the rheological measurements carried on, are described. These measurements were conducted on a cone-plate rheometer, on a visco-analyser and on a tackmeter. The influence of temperature on the rheological properties of liquids is examined. The frequency-temperature superposition principle, applied with the appropriate conditions, allowed the simulation of the working mode at high frequency. Correlations between viscoelastic properties, and more specifically values of tg, and tack measurements are presented.