Influence of dwell time and temperature on the measured gloss of printed UV-inks containing aluminum pigments

Abstract

AbstractThis study investigates the relationship between measured gloss and the microstructure of printed UV-inks containing aluminum pigments. Using a laboratory flexo printing machine, UV-inks containing leafing-type vacuum metallized pigments were printed onto Chromolux paper and primed MultiArt Gloss paper. The time between printing and curing of the ink (dwell time) was varied between the experimental runs. For some samples, hot air was applied onto the uncured UV-ink during the dwell time. The influence of heat (hot air) and dwell time on gloss and the topography of the pigment layer as well as the influence of the substrate was investigated. Roughness and waviness data were obtained using a confocal microscope (Sensofar PLu Neox), gloss measurements were obtained using an IQ-S gloss meter. It was shown that a longer dwell time as well as hot air has a positive influence on the specular gloss measured on the metallic ink printed on Chromolux paper. Also, good correlations could be found between specular gloss, roughness, and waviness, respectively. For primed Multi Art Gloss paper, however, a longer dwell time and hot air can have a negative influence on specular gloss. Also, correlations between roughness, waviness and specular gloss are not as strong as for Chromolux paper.