The surface quality of papers impregnated with a mimosa tannin resin and a MUF resin for application as surface coating on wood panels was compared. The impregnated papers were conditioned to 23% and 10% moisture contents and pressed on to beech plywood. Moisture content of the impregnated papers before pressing was found to influence the abrasion resistance for both mimosa tannin resin and MUF resin impregnated papers. Colour measurements were carried out to relate the different paper colours to the two different moisture contents at pressing. Mimosa tannin impregnated papers at 23% moisture content had a lighter shade compared to impregnated papers with mimosa tannin resins at 10% moisture content. Impregnated papers with mimosa tannin resin gave excellent results for water vapour resistance, cross-cut test and abrasion resistance compared to papers impregnated with MUF resin according to relevant standards. [ABSTRACT FROM AUTHOR]
Derluyn, H., Janssen, H., Diepens, J., Derome, D., and Carmeliet, J.
Subjects
*PAPER, *BOOKS, *MOISTURE, *PERMEABILITY, *ATMOSPHERIC water vapor, *HYSTERESIS
Abstract
This study presents experimental analysis and numerical modeling of hygroscopic moisture buffering by paper and books. First, a literature review of moisture transport properties of paper is presented. Experimental work on two paper types includes SEM analysis of the paper structure, determination of sorption isotherms and water vapor permeability measurements. A hysteretic model for paper is presented, which is based on the measurement of the main adsorption and desorption curves. It is shown that the water vapor permeability in a hysteretic model is dependent on the moisture content and not on the relative humidity. Books consist of several paper sheets with air layers between the sheets. To take the air layers into account, a parallel transport model is proposed to determine the effective moisture transport properties of books taking into account the air layers. The dynamic hygroscopic behavior of small book samples was measured. It is shown that, although the water vapor permeability of different paper types can be quite different, the effusivity of a book highly depends on the presence of the air layers and can therefore remain comparable for different paper types. [ABSTRACT FROM AUTHOR]