New findings for interactions and mechanisms in paper sizing with ASA and AKD
- The purpose of this work was to develop a deeper understanding of the mechanisms in sizing and to minimise interactions with fillers and other chemical additives. It has been shown that the mechanism of the synthetic sizing agents (ASA and AKD) – as often described in the literature - can not be attributed to the esterification with the hydroxyl groups of the cellulose. In fact, the optimal effect of these sizing agents is much more dependant on a fine distribution, mobility and orientation of ASA and AKD molecules. It was observed that the main part of the ASA and AKD is present in an unbound (hydrolysed) form. However, the hydrolysed ASA and AKD can significantly contribute to sizing when it is finely distributed and well orientated. Sizing agents orientated in the opposite do not contribute to sizing but they can even decrease the existing sizing level. Furthermore, it was shown that sizing agents adsorbed onto fillers do not significantly affect the water absorption (penetration) but they can increase the surface hydrophobicity (wetting). Highly anionic products such as dispersants interact with cationic sizing agents due to the opposite charge. As regards the cationic additives, especially starch and aluminium products have a very positive effect on ASA sizing. Surface-active substances such as defoamers and deaerators have no effect on the size retention. However, depending on the type and structure, they can have a huge effect on the sizing level. Generally, hydrophobic defoamers (e.g. fatty acid ethoxylates) have a far more negative impact on sizing, as compared to the more hydrophilic deaerators (e.g. fatty alcohols). These results show possibilities how sizing agents can be used more effectively, process disturbances avoided, and costs reduced.
Author: | Emanuele Martorana, Sebastian Porkert, Stephan Kleemann |
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URN: | urn:nbn:de:bvb:m347-dtl-0000000012 |
Document Type: | Conference Proceeding |
Language: | English |
Date of Publication (online): | 2022/01/26 |
Year of first Publication: | 2010 |
Publishing Institution: | Hochschule für angewandte Wissenschaften München |
Contributing Corporation: | Internationales Münchner Papier Symposium, 10.-12. März 2010 |
Release Date: | 2022/01/26 |
GND Keyword: | LeimenGND; PapierGND |
Page Number: | 27 |
Note: | Vortrag beim Internationalen Münchner Papier Symposium; Parallele Sprachausgabe (deutsch): Neue Erkenntnisse zu Wechselwirkungen und Mechanismen bei der Papierleimung mit ASA und AKD |
Departments and Institutes: | Fakultäten der Hochschule München / FK 05 Fakultät für Technische Systeme, Prozesse und Kommunikation |
Dewey Decimal Classification: | 6 Technik, Medizin, angewandte Wissenschaften / 66 Chemische Verfahrenstechnik |
Illustrations: | Illustration/en |
Illustrations: | grafische Darstellung/en |
Licence (German): |