WHAT IS THE AGE OF RECYCLED FIBERS TODAY AND TOMORROW

Because of further intensified waste paper reutilization on the nation al as well as on the international scene the quality of papers contain ing recycled fibers might be affected. It is well known that recycled fibers pass recycling systems more often in case of increased reutiliz ation rates. This results in an ununiform age distribution of recycled fibers as components of different paper furnishes. Based on a simplif ied recycling system, characterized by identical reutilization rate of all paper grades produced in an area, the age distribution can be eas ily calculated according to an one-parameter model. In a next step, we have succeeded in establishing an extended model which takes differen t past history of various waste paper grades into account, originating from waste paper-free and waste paper-containing paper grades. Finall y, we have derived a multi-parameter model which is based on a variety of waste paper grades, on imports of various paper grades and differe nt yields of fillers, mechanical pulp and chemical pulp in stock prepa ration of recycled fibers. Considering this, we are able to determine age distributions of any waste paper-containing paper grade in any cou ntry