A test apparatus for evaluating edge wicking in sized paperboard suitable for retortable packaging
2007 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, Vol. 22, no 2, 194-199 p.Article in journal (Refereed) Published
The development of packaging board for liquids has been followed by the development of packaging laminate based on paperboard for canned food. This packaging will be filled with a food product and then exposed to high-temperature steam. A test apparatus is needed to simulate the preservation process and facilitate study of critical factors affecting such boards that must be highly water repellent. This paper presents an example of one such apparatus that can be used to study edge wicking in boards. The test apparatus consists of a large mixing chamber, where saturated steam and pressurised air can be mixed and a smaller test chamber in which the test sample is placed on a cooling plate to simulate the temperature gradient occurring when a package of cold food is preserved by heat sterilisation. Test samples can also hang freely in the test chamber. In this study, one commercial board and one laboratory-made board were exposed to saturated steam at temperatures between 112 degrees C and 130 degrees C, corresponding to a pressure of between 1.53 and 2.70 bar. The temperature of the cooling plate was regulated by varying the temperature of the inlet water between 24 degrees C and 72 degrees C. The results show that the temperature of the saturated steam has a large effect on edge wicking - the higher the temperature, the greater the edge wicking. The study also examined the effect of the magnitude of the temperature gradient that occurs when the board is placed on the cooling plate and exposed to saturated steam. It was found that differences in the temperature of the cooling plate do not affect edge wicking at a constant steam temperature.
When samples on the cooling plate are exposed to high-temperature steam, water condensation takes place at the board edge, resulting in water migration into the structure and a clear liquid front in the board. In freely hanging samples, which were not exposed to condensation, the water uptake was uniform throughout the structure. Vapour phase transport took place rapidly throughout the structure and was followed by much slower water uptake into the fibres.
Place, publisher, year, edition, pages
2007. Vol. 22, no 2, 194-199 p.
edge penetration, AKD-sizing, wicking, moisture content, near-infrared spectroscopy, liquid packaging board, autoclaving
Paper, Pulp and Fiber Technology
IdentifiersURN: urn:nbn:se:kth:diva-6273DOI: 10.3183/NPPRJ-2007-22-02-p194-199ISI: 000248057800008OAI: oai:DiVA.org:kth-6273DiVA: diva2:10945
QC 20101125. Uppdaterad från Manuskript till Artikel (20101125). Tidigare Titel: "A test apparatus for evaluatin edge wicking in sized boards used for preserved fool".