Download Gas and moisture barrier on bio-based packaging materials

Gas and moisture barrier on bio-based packaging materials by atomic
layer deposition
Terhi Hirvikorpi*1, Mika Vähä-Nissi1, Jenni Sievänen1,Riku Talja1, Ali Harlin1 and Maarit Karppinen2
1
VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O.Box 1000, FI-02044 VTT,
Finland
2
Laboratory of Inorganic Chemistry, Aalto Univ. School of Sci. and Tech., Kemistintie 1A. P.O.Box
16100, 00076 Aalto, Finland
* [email protected]
Packaging materials consist often of layers of different polymers and aluminum foil, which makes sorting, and
material and energy recovery challenging. On the other hand, barrier properties of biopolymers, especially
against moisture, are not yet on a sufficient level for more demanding packaging applications. New innovations
are thus needed in order to develop new packaging materials to enhance the packaging performance. For thin
film barrier materials promising new aspects may be found in the improved performance and waste management
In our previous studies [1-2] we have demonstrated significantly enhanced barrier properties towards oxygen
and water vapor with thin Al2O3 coatings using the atomic layer deposition (ALD). In addition to these studies,
the effect of corona pre-treatment on the performance of Al2O3 and SiO2 gas barrier layers applied by ALD onto
polymer coated paperboards was studied [3]. For SiO2 depositions a new precursor, bis(diethylamido) silane,
was used.
Al2O3 and SiO2 layers were then successfully deposited at low temperature on these fiber-based substrates. The
positive effect of the corona pre-treatment of the polymer coated boards on the barrier properties after the ALD
deposition was more significant with the polyethylene coated paperboard and with thin deposited layers. This
supports our hypothesis concerning more favorable substrate surface chemistry after corona pre-treatment,
especially with thin deposited layers. In addition, cross-linking of polymer surface layer may decrease diffusion of
precursors into the polymer matrix. These are more important than the less likely increase in surface roughness
during the corona pre-treatment. In the case of oxygen barrier, SiO2 performed similarly to Al2O3 with the PE
coated board, while performance of SiO2 with the biopolymer coated board was more moderate. Corona
treatment also evened out the surface properties of the samples.
To take the ALD one step further there are activities to develop a continuous process, which could make this
technology interesting for the packaging industry. There are already patent applications concerning such a
process [4-6]. Recently our interest has been in developing new bio-based polymers from renewable sources.
These polymers from renewable sources are obtained e.g. from wood or pulp, and they have interesting barrier
characteristics. In this poster presentation, our previous studies [1-3] as well as the future development will be
summarized.
References
[1] T. Hirvikorpi, M. Vähä-Nissi, T. Mustonen, E. Iiskola, M. Karppinen, Thin Solid Films, 518 (2010) 2654.
[2] T. Hirvikorpi, M. Vähä-Nissi, A. Harlin, M. Karppinen, Thin Solid Films, in press (2010).
[3] T. Hirvikorpi, M. Vähä-Nissi, A. Harlin, J. Marles, V. Miikkulainen, M. Karppinen, submitted to Appl. Surf. Sci.
(2010).
[4] A. Erlat, E. Breitung (General electric company), PCT application WO2008/057625 A2.
[5] D.Levy (Easman Kodak) US patent application US2007/0238311 A1.
[6] J. Yudovsky (Applied Materials Inc.), US patent application US2004/0067641 A1.