Some paper and paperboard grades require strength also when rewetted. The purpose of this study was to investigate the impact of web forming method, different foaming agents, polyamideamine-epichlorohydrin (PAE) wet strength resin, and retention aids on the strength development of hand sheets. Only a slight, if any, improvement in dry tensile strength due to PAE resin was observed. PAE improved the wet strength of the water-laid sheets, and the retention systems had a minor but positive impact. Although wet strength was lower at given PAE addition levels, the trend was similar with the sheets foam-laid with an anionic foaming agent, except at high PAE levels. With the non-ionic surfactant the maximum level of wet strength was reached already at a low PAE addition level and use of retention aids decreased wet strength. Such differences between the water- and foam-laid sheets are most likely due to the chemical interactions between PAE, foaming agents, and other additives.
The authors wish to thank Metsä Fibre for providing the pulp, and all the chemical suppliers for the product samples.
Conflict of interest: The authors declare no conflicts of interest.
Al-Qararah, A., Hjelt, T., Kinnunen, K., Beletski, N., Ketoja, J. (2012) Exceptional pore size distribution in foam-formed fibre networks. Nord. Pulp Pap. Res. J. 27(2):226–230.10.3183/npprj-2012-27-02-p226-230Search in Google Scholar
Al-Qararah, A., Hjelt, T., Koponen, A., Harlin, A., Ketoja, J. (2013) Bubble size and air content of wet fibre foams in axial mixing with macro-instabilities. Colloids Surf. A, Physicochem. Eng. Asp. 436:1130–1139.10.1016/j.colsurfa.2013.08.051Search in Google Scholar
Bessonoff, M., Paltakari, J., Laine, J., Paulapuro, H. (2006) Effects of A-PAM/C-PAM complexes on retention, formation and dewatering of papermaking pulp. In: 92nd Annual Meeting of PAPTAC. Montreal, Canada, February 7–9, PAPTAC. pp. A117–A121.Search in Google Scholar
Crisp, M. T., Riehle, R. J. (2009) Wet-strengthening of paper in neutral pH papermaking conditions. In: Applications of Wet-end Paper Chemistry, 2nd Ed, Eds. Thorn, I., Au, C. O., Springer, Dordrecht, Heidelberg, London, New York. pp. 147–170.10.1007/978-1-4020-6038-0_8Search in Google Scholar
Espy, H. H. (1995) The mechanism of wet-strength development in paper: a review. Tappi J. 78(4):90–99.Search in Google Scholar
Fisher, S. A. (1996) Structure and wet-strength activity of polyaminoamide epichlorohydrin resin having azetidinium functionality. Tappi J. 79(11):179–187.Search in Google Scholar
Kinnunen, K., Lehmonen, J., Beletski, N., Jetsu, P., Hjelt, T. (2013) Benefits of foam forming technology and its applicability in high MFC addition structures. In: The 15th Pulp and Paper Fundamental Research Symposium, September 8–13, Cambridge, U.K., The Pulp and Paper Fundamental Research Society. pp. 837–850.Search in Google Scholar
Lappalainen, T., Lehmonen, J. (2012) Determinations of bubble size distribution of foam–fibre mixture using circular Hough transform. Nord. Pulp Pap. Res. J. 27(5):930–939.10.3183/npprj-2012-27-05-p930-939Search in Google Scholar
Lappalainen, T., Salminen, K., Kinnunen, K., Järvinen, M., Mira, I., Andersson, M. (2014) Foam forming revisited. Part II. Effect of surfactant on the properties of foam-formed paper products. Nord. Pulp Pap. Res. J. 29(4):689–699.10.3183/npprj-2014-29-04-p689-699Search in Google Scholar
Lehmonen, J., Jetsu, P., Kinnunen, K., Hjelt, T. (2013) Potential of foam-laid forming technology in paper applications. Nord. Pulp Pap. Res. J. 28(3):392–398.10.3183/npprj-2013-28-03-p392-398Search in Google Scholar
Mira, I., Andersson, M., Boge, L., Blute, I., Carlsson, G., Salminen, K., Lappalainen, T., Kinnunen, K. (2014) Foam forming revisited Part I. Foaming behaviour of fibre-surfactant systems. Nord. Pulp Pap. Res. J. 29(4):679–688.10.3183/npprj-2014-29-04-p679-689Search in Google Scholar
Obokata, T., Isogai, A. (2007) The mechanism of wet-strength development of cellulose sheets prepared with polyamideamine-epichlorohydrin (PAE) resin. Colloids Surf. A, Physicochem. Eng. Asp. 302(1–3):525–531.10.1016/j.colsurfa.2007.03.025Search in Google Scholar
Obokata, T., Isogai, A. (2009) Wet-strength development of cellulose sheets prepared with polyamideamine-epichlorohydrin (PAE) resin by physical interactions. Nord. Pulp Pap. Res. J. 24(2):135–140.10.3183/npprj-2009-24-02-p135-140Search in Google Scholar
Wågberg, L., Björklund, M. (1993) On the mechanism behind wet strength development in papers containing wet strength resins. Nord. Pulp Pap. Res. J. 8(1):53–58.10.3183/npprj-1993-08-01-p053-058Search in Google Scholar
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