Patent ID: 8197640

Claim:
A method for manufacturing paper or paperboard sheet with increased strength, the method comprising the steps of: providing a fiber slurry and a cationic polyacrylamide composition, each of which is suitable for use in making paper or paperboard; providing at least one crosslinker composition comprising at least one aldehyde generating compound capable of forming at least two or more covalent bonds to functional groups present in the cationic polyacrylamide composition; mixing the cationic polyacrylamide composition and the crosslinker composition to form a mixture; reacting the mixture in a reactor in a continuous process at a mill site having a papermaking machine to form a concentrated strength enhancer; diluting the concentrated strength enhancer into a strength enhancer; adding the strength enhancer to the fiber slurry at the papermaking machine; and forming the paper or paperboard sheet, wherein the increased strength is increased wet strength or increased dry strength.