Characterization of oil-proof papers containing new-type of fluorochemicals Part 1: Surface properties and printability

Commercial oil-proof papers containing new family of fluorochemicals were characterized in terms of surface and barrier properties and printability. XPS analyses demonstrated that the fluorochemicals added to these papers had shorter perfluoroalkyl chains, compared to those used few decades ago. Contact angle measurements were performed and the obtained data were processed according to Owens–Wendt–Rabel–Kaelble (OWRK) approach, in order to calculate the surface energy of the investigated samples. This set of experiments revealed that the values of the surface energy of the non-coated surfaces of oil-proof papers were low enough (i.e. about 5 mJ/m2) to repel both water and oil. The surface energy of the coated sides was, instead, close to that of classical organic surfaces (i.e. around 30 mJ/m2), which predicts their potentially good printability. In fact, microcontour test was performed as the basic test for evaluating printability of oil-proof papers and showed that ink pigment retention was not significantly influenced by the level of barrier to oil. However, the surface roughness was found to play a key role in such properties.