Strength improvement of OCC by thermal and chemical treatments

This study was carried out to provide improvement of recycled paper strength made from OCC. Chemical treatment of OCC pulp was carried out using 1% sodium chloride as ion exchange stage and then extraction by 3% and 5% sodium hydroxide based on oven dried pulp. Slurry temperature during the chemical reaction was adjusted to 25 and 70 °C. Handsheets were made based on a new standard method by KCL sheet former using a closed water system. Water retention value (WRV)، sheet density and strength were measured to characterize the treated fiber properties. No significant differences in WRV were found among control and treated pulps despite of maximum increasing of 25% applying 3% NaOH، ionic exchange and room temperature. The mentioned condition wasselected as the best condition which significantly improved apparent density، burst strength، tear strength and RCT.