Influence of UV curing varnish coating on surface properties of paper

In order to achieve better properties of the printing substrates their improving is possible in various ways. In this article the possibility of the substrate improving is analyzed with different surface coverage of varnishes cured by UV radiation, where three characteristic papers were used (fine art glossy paper, offset paper and calendered paper). The applied methods are based on measuring the optical properties with the varnish impregnated surface (colouring, gloss, smoothness), as well as determining the physical property of absorbency. The double properties of the printing substrates are obtained by the layer of UV varnish which is cured by LED light. The investigation results show that the absorbency decreases on gloss coated paper by the application coating of UV varnish, while it increases on uncoated papers (offset paper and the calendered one). The varnish coating with smaller coverage (33% UV varnish) is not relevant for the absorbency and for optical properties of the natural papers. Important changes in roughness and optical properties are achieved with 66% coating which is especially visible on fine art paper.