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Method for producing paper, paperboard and cardboard having high dry strength

  • US 8,647,470 B2
  • Filed: 10/14/2010
  • Issued: 02/11/2014
  • Est. Priority Date: 10/20/2009
  • Status: Active Grant
First Claim
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1. A process for the production of paper, board, and cardboard having high dry strength, the process comprising:

  • (I) metering into a paper stock an aqueous composition comprising a nanocellulose comprising cellulose fibers and at least one anionic polymer and optionally a water-soluble cationic polymer;

    (II) draining the paper stock, to obtain paper product; and

    (III) drying the paper product;

    wherein the anionic polymer comprises, as polymerized units;

    (a) at least one monomer selected from the group consisting of a C1- to C20-alkyl acrylate, a C1- to C20-alkyl methacrylate, a vinyl ester of a saturated carboxylic acid comprising up to 20 carbon atoms, a vinylaromatic comprising up to 20 carbon atoms, an ethylenically unsaturated nitrile, a vinyl ester of a saturated, monohydric alcohol comprising 1 to 10 carbon atoms, a vinyl halide, and an aliphatic hydrocarbon comprising 2 to 8 carbon atoms and one or two double bonds;

    (b) at least one anionic monomer selected from the group consisting of an ethylenically unsaturated C3- to C8-carboxylic acid, a vinylsulfonic acid, acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, vinylphosphonic acid, and salts thereof;

    (c) optionally, at least one monomer selected from the group consisting of a C1- to C10-hydroxyalkyl acrylate, a C1- to C10-hydroxyalkyl methacrylate, acrylamide, methacrylamide, an N—

    C1- to C20-alkylacrylamide, and an N—

    C1- to C20-alkylmethacrylamide; and

    (d) optionally, a monomer comprising at least two ethylenically unsaturated double bonds in the molecule.

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