Patent ID: 7972478
Filing Date: 2011-07-05
Classification: C08F,D21H

Abstract:
1. Production method for a sheet of paper and/or cardboard, according to which, before forming said sheet from a fibrous suspension, are added to the fibrous suspension, separately or in a mixture, in any order of addition, in one or more points of injection, at least two dry strength agents, respectively: a first agent corresponding to a Hofmann degradation product in a solution on a base (co)polymer containing at least one non-ionic monomer selected from the group including acrylamide and/or methacrylamide, N,N dimethylacrylamide and/or acrylonitrile, and a second agent corresponding to a (co)polymer with an anionic charge density greater than 0.1 meq/g, wherein the Hofmann degradation product comprises an organic polymer produced at a temperature of 0 to 45° C. and at a concentration greater than 3.5% by weight, and wherein the first and second agents are added to the fibrous suspension at 0.01 to 2% each by weight of active polymer material in relation to a dry weight of the fibrous suspension.