Preliminary report on properties and interaction of layers in “board-biodegradable primer-printing ink” screen-printed system

Surface phenomena in printing are extremely important for understanding and optimizing the interaction of materials involved in the process of graphic reproduction. In order to protect absorbent printing substrates from moisture penetration, to strengthen mechanical properties or to ensure better adhesion of the printing ink to the substrate, the substrates are often coated with protective coatings (primers) before printing. The adhesion parameters between the coating and the printing ink then become extremely important for assessing the durability, but also the quality of the print. In this research, biodegradable primers (polycaprolactone and polylactic acid) were applied on a board substrate with the primary aim of reducing the permeability to water vapour in combination with printed ink layers. Two types of water-based screen printing inks were printed on the primed substrates: ink prepared using the transparent base, and the ink prepared using the opaque white base. Two meshes with different screen count were used (32 l/cm and 60 l/cm). The research focused on the possibility of reducing the water vapour transmission rate using the inks and biodegradable primers, and at the same time analysing the interaction of biodegradable primers and printing inks by determining the surface and interfacial properties in the "printing substrate-primer-printing ink" system. The results of the research have contributed to the optimization of the screen-print quality on the primed absorbent and porous substrates.