engleski

Infulence of ink solvent concentration on wetting of flexo printing plate and PE foil

The imprints quality is highly influenced by the ink transfer from the printing plate to the printing substrate. Ink transfer depends on the surface characteristics of the printing plate and substrate and the printing ink composition as well. The aim of this research was to determine wetting characteristics of the printing plate and printing substrate depending on printing ink composition in the flexographic printing. For this purpose samples of printing ink were made with varying solvent concentration. Evaluation of the printing ink was made by measuring viscosity and the characterisation of surface topography of printing plate and PE foil was made by measuring roughness parameters. To determine wetting characteristics of the prepared samples of printing inks on the printing plate and PE foil measurements of contact angle were performed. Obtained results showed that the ink composition has significant influence on the printing ink viscosity and on the wetting of the printing plate but on the printing substrate as well. The contact angle between printing ink and both investigated surfaces (printing plate and PE foil) is increasing by reducing the solvent concentration (higher viscosity) thereby resulting in worse wetting. The conducted research showed the importance of the printing ink composition on the wetting of the printing plate and printing substrate, consequently on the ink transfer from the ink tray to the imprint. Furthermore, one must monitor all observed parameters (surface topography, ink viscosity, wetting characteristics) in order to achieve best printing results.

flexography; printing ink; polyethylene; contact angle; surface topography

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