TY - CONF A1 - Martorana, Emanuele A1 - Hoffmann, Jochen A1 - Kleemann, Stephan T1 - Post-curing and size reversion – An extended mechanism of ASA sizing N2 - Assuming internal sizing agents like AKD and ASA to be chemically bound onto the cellulose fibre one would expect sizing of paper to be stable over time. Further, ASA as the more reactive substance, will develop sizing straight after drying on the paper machine. Even though papermakers are got used to these benefits of internal sizing after many years of practical experience, there are also observations of postcuring and fugitivity of sizing, which do not fit to the common sizing theory. Investigations on a fine paper model have shown ASA to move from a sized paper into a blank sheet, which is in direct contact. Detection and quantification of ASA was carried out by means of NIR-spectroscopy. Mobility of ASA is enhanced at elevated temperature and moisture in the sheet. It goes along with a decrease of sizing level in the sized sheet, whereas the moved ASA does develop almost no sizing in the blank sheet, even after heat treatment. Only after surface treatment with an aluminium compound it can be re-activated for sizing. Based on these and additional findings we have developed a model of ASA sizing, which takes into account such untypical properties as post-curing and fugitivity. KW - Leimen KW - Papier Y1 - 2022 UR - https://opus4.kobv.de/opus4-hm/frontdoor/index/index/docId/312 UR - https://nbn-resolving.org/urn:nbn:de:bvb:m347-dtl-0000000191 N1 - parallele Sprachausgabe (deutsch): Nachreife und Leimungsschwund – Neue interessante Effekte bei geleimten Papieren ER -