INFLUENCE OF LOW MOLECULAR MASS POLYACRYLAMIDE OVER THE PROPERTIES OF RECYCLED PRINTING PAPER.

Hydrophilic natural and synthetic organic substances, which have emphatical affinity with pulp fibers are used for improving the dry strength properties of paper. The study was carried out with secondary fiber material (SFM) from newspapers and neutrally sized offset printing paper. Paper samples were prepared in laboratory conditions from an anionic direct dye, a sizing agent based on alkyl ketene dimmer (AKD), a filler and a cationic low molecular mass Dry Strength Resin (DSR). At constant AKD (1 %, 2 %, 3 % as a commercial product) consumption, the DSR quantity was varied (0.1 %, 0.2 %, 0.3 % of oven dry fibers (o.d.f.). The cationic DSR is appropriate for producing neutrally-sized papers containing recycled fibers with CaCO3 as a filler. It contributes to filler retention and sizing, and the improves strength properties of paper. It is observed that with increasing the DRS consumption the color of the paper becomes darker. [ABSTRACT FROM AUTHOR]