METHOD FOR DECREASING FLUORESCENCE IN DEINKED PULP

摘要

PURPOSE: To effectively remove fluorescence from fibers such as secondary fibers e.g. in a reclaiming process of paper containing fluorescent dye and to obtain paper capable of being included in food packaging paper materials by bringing pulp fibers into contact with ozone in two or more stages. CONSTITUTION: This method is to treat pulp fibers containing fluorescent dye with a sufficient quantity of ozone in two or more stages. An intermediate washing stage or bleaching stage preferably is placed between ozone contacting stages divided into two or more stages. Splitting the total ozone charge into two or more stages provides a much more effective process for removing fluorescence and improving clearness.