Characterization of oil-proof papers containing a newtype of fluorochemicals
Résumé
Six commercial oil-proof paper specimens, which had been manufactured with application of a new type of fluorochemical agent on their surface, were evaluated in terms of water- and oil-proof and printing properties.The new agent had been designed to comply with standards requiring six or fewer carbons in the perfluorinated alkyl chain. First, the paper samples were characterized in terms of classical properties, such as their thickness, density and ash content. The ashes were collected after the calcination of the paper samples and their contents were found to be around 15-17 wt%. The elemental analysis of these minerals indicated that they were inorganic fillers and pigments (Al- and Si-based). No traces of fluorine components were detected in this mineral part, because the fluorochemicals used in the oil-proof papers were organic-based molecules, which underwent total combustion during the calcination process. Stöckigt sizing and Cobb60 tests clarified that all the paper samples had certain levels of water-proof properties both on the non-coated and on the coated sides. On the other hand, the result of the Kit test indicated that the paper samples having fluorochemicals on the non-coated surfaces had a large oil-proof barrier. The XPS of the coated surface revealed that the binder used is most probably a styrene-butadiene-like polymer and that the pigments are kaolin, calcium carbonate or a mixture of the two. On the coated surfaces of all the paper samples, oily liquids did not penetrate into the coating layers, but spread rapidly over them. The ink porosimetry test by dye-type ink was adopted for the evaluation of ink absorption of the paper samples. On the coated surfaces, all the paper samples absorbed small quantities of ink. Although further investigation is required for better understanding the ink absorption mechanisms and the retention of dye components on the coated surfaces, this study proved that water- and oil-proof effects largely influenced the behaviors of dye-type ink absorption on the paper samples.