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Use of diallyldimethylammonium chloride acrylamide dispersion copolymer in a papermaking process

  • US 6,238,521 B1
  • Filed: 05/21/1999
  • Issued: 05/29/2001
  • Est. Priority Date: 05/01/1996
  • Status: Expired due to Term
First Claim
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1. In a papermaking process consisting essentially of:

  • forming an aqueous cellulosic papermaking slurry;

    adding to the slurry certain additives, with said certain additives selected from the group including;

    coagulants;

    sizing agents; and

    mineral fillers;

    draining the slurry to form a sheet; and

    drying the sheet to form a paper sheet;

    the improvement comprising adding to the slurry, prior to it being drained;

    from about 0.02 lbs polymer/ton to about 20 lbs polymer/ton of a cationic dispersion polymer;

    which cationic dispersion polymer is a copolymer comprising about 30 mole % diallyldimethylammonium chloride (DADMAC) and about 70 mole % acrylamide (AcAm); and

    dispersion polymer has an RSV of about 5.0 dl/g; and

    adding to the slurry, either before or after said cationic dispersion polymer is added and the slurry is drained, from about 0.05 lbs microparticle/ton to about 25.0 lbs microparticle/ton of a microparticle selected from the group consisting of a) copolymers of acrylic acid and acrylamide;

    b) bentonite; and

    c) dispersed silica;

    with the proviso that said coagulant cannot be a cationic dispersion copolymer comprising about 30 mole % diallyldimethylammonium chloride (DADMAC) and about 70 mole % acrylamide (AcAm).

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