Patent ID: 8894817
Filing Date: 2014-11-25
Classification: D21H

Abstract:
1. A method of increasing the dry strength of a paper substrate, the method comprising adding a flocculant and starch to a paper substrate and then adding a glyoxalated polyacrylamide (GPAM) copolymer to the paper substrate, wherein: said addition of GPAM occurs in the wet-end of a papermaking process after the substrate has passed through a screen but no more than 18 seconds before the substrate enters a headbox, the GPAM copolymer is constructed out of acrylamide-acrylic acid (AcAm-AA) copolymer intermediates having an average molecular weight of 5.7-9 kD, the GPAM copolymer has an average molecular weight of 0.6-3 MD.