A METHOD FOR REDUCING ALKALINE DARKENING OF MECHANICAL PULP CONTAINING A CALCIUM CARBONATE FILLER
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Countries |
Status |
Issued |
Issue # |
*US CON 1 |
Issued |
2/14/2006 |
6998015 B1 |
| PATENT ABSTRACT [Paprican Ref. No. 4143] |
A method is disclosed for reducing alkaline darkening of mechanical pulp caused by the presence of calcium carbonate filler during production. The method consists of adding a quantity of sodium sulphite, or the like, to the mechanical pulp and the filler. The method is usefully applied in the production of mechanical pulp and paper in which calcium carbonate is used as a filler and also in the production of paper at neutral or mildly alkaline conditions. |
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