Uniformity of liquid absorption by coatings: Technique and impact of coating composition
2012 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, Vol. 27, no 2, 456-465 p.Article in journal (Refereed) Published
The interaction between a liquid and a paper surface is important for a number of paper treatment processes, where absorption is of special significance during printing. Many absorption measurement techniques use a large available volume of liquid to characterise absorption, when compared to the volume of the coating. The uniformity of the absorption is also seldom characterised. We have developed a new technique, which is presented in this article, to study the uniformity of absorption of a small amount of liquid. This technique is based on the short-time absorption (tenth of a second) of a coloured liquid, the blotting of excess liquid and a characterisation of the pattern of the stain. This method made it possible to detect differences among coating layers with different compositions. In many cases, the absorption non-uniformity could be linked to variations in the coating thickness and/or wettability. The thinner and thicker areas of the coating layers were interpreted as having different pore structures. Neither the coating thickness nor the wettability could provide a full explanation, which showed the need to develop a method to characterise absorption uniformity instead of only relying on measuring the total absorption potential.
Place, publisher, year, edition, pages
2012. Vol. 27, no 2, 456-465 p.
Coated boards, Flexographic printing, Liquid absorption, Test method
IdentifiersURN: urn:nbn:se:kau:diva-34906DOI: 10.3183/NPPRJ-2012-27-02-p459-465OAI: oai:DiVA.org:kau-34906DiVA: diva2:780742