Resumo (PT):
Abstract (EN):
The investigation evaluates the benefits of impulse drying on the properties of papers containing polyamide epichlorohydrin (PAE) resin, as a wet strength additive. PAE-containing paper samples were impulse-pressed, and either dried in restraint mode at 23° or in an oven at 105°. The evolution of wet and dry tensile strength values was measured as a function of storage time. For comparison, the PAE paper samples were pressed and oven-dried under standard conditions. Different times and temperatures were tested and the evolution of paper properties was followed. In standard pressing conditions, the effect of drying time on the resin curing rate was more pronounced, comparatively with that induced by the drying temperature. The impulse drying technique was found to affect positively the curing rate of the wet strength resin. This effect was not high enough to prevent delamination, which was observed at certain pressing temperatures, especially with sheets made from highly beaten pulps. However, when sheet delamination was not observed, the impulse drying technique was seen as increasing paper density and, consequently, sheet strength was generally increased. Impulse drying was found, in fact, to improve the wet and dry tensile index.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
13