Tailoring printability properties of paper with small amounts of starch derivatives

Chemical processing of paper surface offers alternatives for controlling the unequal sidedness of paper surfaces, for increasing barrier properties, and for adjusting absorption characteristics for different printing methods. Chemical characteristics, in addition to physical properties of paper, are significant in the printing process, but their effects are not known well enough. Tailor-made and interactive paper (TailorPap) -project was one of the projects funded by Finish National Technology Agency Tekes in NETCOAT network. The aim of TailorPap project was to introduce a new concept in papermaking: A simplified base paper is used to several end products. The surface properties are adjusted by chemical treatment to lower production costs. The project was a collaboration of VTT, Helsinki University of Technology and University of Jyväskylä. The aim of this study was to adjust oil, solvent and water based printing ink absorption properties of paper by treating the surface with small amount of polymer. In order to reach this goal, the hydrophilicity / hydrophobicity ratio as well as ionic properties of the starch polymer were modified. The results show that by changing the hydrophobicity and ionic properties of certain polymers the absorption properties and surface energy of polymer treated papers can be tailored. It is possible to reduce significantly penetration and print through of many kinds of printing inks by spreading less than 0,5 g/m2 of polymer on uncoated paper surface. The addition of the polymer is not blocking the paper surface pores, when the amount of polymer is less than 0,5 g/m2. However, the results showed that surface properties could clearly be affected with this low amount of polymer.