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US 8,696,869 B2Granted
Surface application of polymers and polymer mixtures to improve paper strength
AssigneeHercules Incorporated
InventorsSachin Borkar, Marc C. Putnam
Life of this patent
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Abstract
Stable, coating compositions useful for enhancing the dry strength of paper are disclosed. The compositions comprise an aqueous solution of nearly neutral polymer, cationic polymer and starch. Method of using the coating composition to improve the dry strength of paper is also disclosed.
Claims17
A coating composition for a formed paper substrate comprising:
- component A selected from the group consisting of a polyacrylamide having less than 5 molar percent anionic functionality;
- component B selected from the group consisting of a cationic polymer wherein the cationic polymers have charge densities, on a solids basis, in the range of 1.00 to 12.00 meq/g;
- and starch wherein the ratio of component A to component B is from 99:1 to 80:20;
- and wherein the ratio of component A plus component B to starch is from 1:105 to 1:1.
1 more element
A process for making paper with improved dry strength, the process comprising applying to already formed paper a composition, comprising:
- component A selected from the group consisting of a polyacrylamide having less than 5 molar percent anionic functionality, component B selected from the group consisting of a cationic polymer wherein the cationic polymers have charge densities, on a solids basis, in the range of 1.00 to 12.00 meq/g, and starch;
- wherein the ratio of component A to component B is from 99:1 to 80:20;
- and wherein the ratio of component A plus component B to starch is from 1:105 to 1:1.
Dependencies are inferred from the claim text.