Paper making
First Claim
1. In a paper making process, the improvement that resides in adding a medium/high molecular weight cationic polymer having an intrinsic viscosity in the range 5 to 25 dl/g and having a charge density of 0.78 to 5 equivalents cationic nitrogen per kg to the furnish prior to its entry into a headbox, subjecting the furnish to which said polymer has been added to shear and thereafter adding a natural hectorite to the furnish prior to introducing it to the headbox without subjecting the furnish to any substantial further shearing, the amount of hectorite used being such as to result in the range of 0.5 to 6 lbs/ton dry base sheet and the weight ratio of medium/high molecular weight cationic polymer to hectorite being 0.5:
- 1 to 10;
1.
1 Assignment
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Accused Products
Abstract
A process for improving art chemistry in papermaking is accomplished by the addition of a cationic polymer and natural hectorite to the furnish prior to headbox. The cationic polymer has an intrinsic viscosity in the range of 5 to 25 dl/g and a charge density of 0.78 to 5 equivalent cationic nitrogen per Kg. The natural hectorite is added in an amount of 0.5 to 6 lbs/ton dry base sheet and the weight ratio of cationic polymer to natural hectorite being 0.5:1 to 10:1.
97 Citations
15 Claims
- 1. In a paper making process, the improvement that resides in adding a medium/high molecular weight cationic polymer having an intrinsic viscosity in the range 5 to 25 dl/g and having a charge density of 0.78 to 5 equivalents cationic nitrogen per kg to the furnish prior to its entry into a headbox, subjecting the furnish to which said polymer has been added to shear and thereafter adding a natural hectorite to the furnish prior to introducing it to the headbox without subjecting the furnish to any substantial further shearing, the amount of hectorite used being such as to result in the range of 0.5 to 6 lbs/ton dry base sheet and the weight ratio of medium/high molecular weight cationic polymer to hectorite being 0.5:
Specification