Making paper which has a high dry strength
AssigneeBASF SE
InventorsSigberg Pfohl, Volkmar Weberndoerfer, Heinrich Hartmann, Friedrich Linhart
Life of this patent
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Abstract
Paper having a high dry strength is made using water-soluble homopolymers of salts or quaternary 1-vinyl-2-imidazolines and copolymers of these salts or quaternary compounds with acrylamide and/or methacrylamide as agents for increasing the dry strength of paper.
Claims2
A process for making paper which has a high dry strength by adding a cationic copolymer to the paper stock and draining the latter with sheet formation, or by applying a cationic copolymer onto the surface of paper, the said copolymer being added in an amount of from 0.05 to 3.0% by weight, based on dry fiber or dry paper, wherein a water-soluble copolymer of 2 to 15% by weight of a compound of the formula ##STR5## where R.sup.1 is CH.sub.3, R.sup.2, R.sup.3 and R.sup.4 are each H, and x.sup.- is an acid radical, and from 98 to 85% by weight of acrylamide, methacrylamide or mixtures thereof, the K value of the copolymer being from 50 to 250.
Dependencies are inferred from the claim text.