Rheological Characteristics of UV Flexo Inks

The aim of this paper is to present some peculiar characteristics of UV flexo inks and to give a brief comparison with a classical water-based ink. Flow measurements were conducted on six free radical UV inks in order to clarify some of their rheological characteristics. These measurements were carried out on a cone-plate rheometer. Different models were applied to characterise the flow of these inks. Correlations between the parameters of the models were established. The influence of temperature and especially the determination of the activation energy of flow was examined. The thixotropic behaviour of inks was quantified and discussed. Finally, some measurements of surface tension are presented.