Relationship between Printability and Rheological Properties of UV-curable Flexographic Ink

Relationship between printability and rheological properties of UV flexographic (flexo) inks were investigated. UV flexo suspensions of carbon black in liquid medium having various binding materials such as acylate pre-polymer, di/multi-functional monomer, and diluents, were used as sample inks. Inks were characterized on a rheometer in terms of steady and dynamic behaviors. To understand the rheological properties of UV flexo inks, we must determine the specific rheological properties of chemical and/or physical interactions of their components (pigments, functional monomers, and pre-polymers). In particular, we discussed the influence of multi-functional monomers and the relationship between the rheological properties and transient networks formed by carbon black. In this study, we investigated the interrelationships between rheological properties of UV flexo inks and chemical and/or physical interactions of their components. To investigate correlations between the printability and the rheological behaviors induced by interfacial interactions between ink compositions, we carried out rheological tests of UV ink suspensions. The results were compared with printing tests so as to find out the relationship between printability and rheological properties of ink.