REPULPING WET-STRENGTH PAPER

A new repulping process that uses a nonchlorinated oxidizing agent and a rewetting agent was found to be very effective in repulping wet-str ength paper that was difficult to break down. The process is particula rly useful in repulping unbleached paper and old corrugated containers (OCC) containing polyaminoamide-epichlorohydrin (PAE) wet-strength re sins. The process involves oxidizing the wet-strength paper at a low p H with inorganic or organic peroxides followed by hydrolyzing the wet- strength paper at a high pH. In field trials, unbleached paper contain ing high levels of PAE resins was repulped to about 95% in mill hydrop ulpers. This process enables papermakers to defiber unbleached paper a nd OCC more efficiently than commonly practiced neutral or alkaline re pulping processes.