Siegwerk launches new deinkable UV flexo varnishes

With the development of new UV flexo varnishes and UV offset inks for commercial and packaging printing, Siegwerk expands its offering of deinkable solutions further improving the recyclability of UV-coated paper and board print products.

For the recycling of paper and fresh fiber board, it is important that ink and varnish films are fragmented into small hydrophobic (water repellent) particles during the recycling process in order to become detached and more easily separated from the substrate fiber. But present standard UV inks still often show an extremely poor deinkability as they form a solid, chemically, and mechanically resistant layer that is strongly attached to the cellulose fiber like an adhesive plastic layer. Therefore, they are difficult to remove during the recycling process resulting in big color spots in the recycled paper. Studies have also shown that prints coated with water-based dispersion varnishes and UV-curing flexo varnishes, similar to UV standard inks, very often produce problems during the paper and board deinking recycling process. During the recycling process, the printed varnish layers are fragmenting either into too small (water-based varnishes) or too big particles (UV varnishes) and cannot successfully be separated from the cellulose fibres. Packaging printing UV offset inks and conventional oil-based inks are often covered with standard UV flexo varnishes. In particular, this problem significantly hampers the recyclability of valuable virgin fiber-based carton board. This also applies to magazine covers printed in web offset with conventional oil-based heatset inks  or UV flexo varnishes.