METHOD FOR MAKING PAPER AND CARDBOARD WITH HIGH DRY STRENGTH AND RESULTING PAPERS AND CARDBOARDS

摘要

Manufacturing a sheet (I) of paper and/or paperboard or analogs comprises adding at least three dry resistance agents, separately or in mixture, to a fibrous suspension by introduction in one or more points of injection, where the first agent (Ia) is a (co)polymer with a cationic charge density greater than 1 meq/g and an amino primary functional group, the second agent (Ib) is synthetic organic (co)polymer with a cationic charge density greater than 0.1 meq/g and the third agent (Ic) is (co)polymer with a anionic charge density greater than 0.1 meq/g. An independent claim is included for a sheet of paper and paperboard, which are obtained by the above process.