Patent ID: 6340407
Filing Date: 2002-01-22
Classification: D21B,D21C,D21D,D21H,Y02W

Abstract:
In a process of making a stock preparation for recycled linerboard or Kraft paper wherein OCC is defibered, cleaned, screened, fractionated into long fibers and short fibers, long fibers being refined to required level of freeness, virgin pulps added to achieve required strength properties, and deposited on a wire and dewatered, the strength properties of the stock are improved by a process comprising the steps of:cutting and/or crushing OCC that contains corrugated medium attached to linerboard into pieces, separating linerboard pieces from corrugated medium pieces, removing any remaining corrugated medium pieces from OCC furnish containing the separated linerboard pieces, adding NaOH to the separated linerboard pieces in the OCC furnish, defibering the separated linerboard pieces in the OCC furnish, eliminating micro-fibrils from long fibers in the OCC furnish, minimizing the loss of long fibers by recovering any long fibers from reject streams, applying dry strength additives to the OCC furnish, and maintaining a furnish pH of from 5.5 to 6.5 at the head box of paper machine.