An Attempt to Reduce Dampening Water Absorption Using Hydrophobic Plasma Coatings

Hydrophobic plasma coatings were deposited on pigment coated paper and their influence on sheetfed offset printability was studied. Three plasma chemistries, fluorocarbon, organosilicone and hydrocarbon, were used to adjust the hydrophobicity of paper surface. The plasma coatings reduced, and in some cases prevented the dampening water absorption into pigment coated paper in both laboratory- and pilot-scale trials. Ink transfer, mottle and ink setting changed due to the presence of the plasma coatings, whereas porosity and surface strength of the pigment coated papers were not affected. Based on the results, the preferred way to improve the print quality with both mineral and linseed oil-based inks is to use plasma chemistry that modifies the paper surface to be hydrophobic and oleophilic.