Abstract: The invention relates to a process for producing paper, board and cardboard of high dry strength by separately adding a polymer comprising vinylamine units and a polymeric anionic compound to a paper pulp, dewatering the pulp and drying the paper products, which comprises using as polymeric anionic compound at least one copolymer obtainable by copolymerizing (a) at least one N-vinylcarboxamide of the formula in which R1 and R2 are H or C1- to C6 alkyl, (b) at least one monoethylenically unsaturated monomer comprising acid groups, and/or the alkali metal, alkaline earth metal or ammonium salts thereof, and if appropriate (c) other monoethylenically unsaturated monomers, and if appropriate (d) compounds having at least two ethylenically unsaturated double bonds in their molecule.

Abstract: The present invention relates to an aqueous composition comprising at least one finely divided filler and at least one water-soluble amphoteric copolymer, a process for the preparation of such a composition and its use as an additive in the production of paper, cardboard and board.

Abstract: Aqueous slurries of finely divided fillers which are at least partly coated with polymers and which are obtainable by treating aqueous slurries of finely divided fillers with at least one water-soluble amphoteric copolymer whose structures are identified in the specification are used as an additive to the paper stock in the production of filler-containing paper, filler-containing cardboard or filler-containing board by draining of the paper stock.

Abstract: Method of producing copolymers by free-radical polymerization of at least one water-soluble N-vinyllactam and at least one hydrophobic comonomer in an organic solvent in the presence of an initiator, where the polymerization is carried out under a gauge pressure such that evaporation of the components is avoided.

Abstract: Aqueous solutions comprising: one or more polymeric components selected from the group consisting of homopolymers of N-vinylpyrrolidone, copolymers of N-vinylpyrrolidone, and mixtures thereof; and hydrogen peroxide; wherein the hydrogen peroxide is present in an amount of 100 to 5000 ppm; and methods of stabilizing aqueous solutions containing one or more polymeric components selected from the group consisting of homopolymers of N-vinylpyrrolidone, copolymers of N-vinylpyrrolidone, and mixtures thereof.

Abstract: Methods of producing vinyllactam copolymers which include: providing at least one water-soluble N-vinyllactam; providing at least one hydrophobic comonomer; and subjecting the at least one water-soluble N-vinyllactam and the at least one hydrophobic comonomer to free-radical polymerization in an organic solvent in the presence of an initiator, under a combination of process measures selected from the group consisting of A and B; wherein: (A) comprises (i) polymerization under reflux, and at least two of (ii), (iii), (iv), (v), (vi), and (vii), wherein (ii) comprises an addition of at least 5 mol % of N-vinyllactam to the polymerization mixture if at least 70 mol % of the total amount of hydrophobic monomer used have completely reacted, (iii) comprises return of condensate formed in the reflux from below to the polymerization mixture, (iv) comprises introduction of the initiator in the form of a solution in an organic solvent from below into the polymerization mixture, (v) comprises addition of N-vinyllacta

Abstract: The invention relates to a process for producing paper, board and cardboard of high dry strength by separately adding a polymer comprising vinylamine units and a polymeric anionic compound to a paper pulp, dewatering the pulp and drying the paper products, which comprises using as polymeric anionic compound at least one copolymer obtainable by copolymerizing (a) at least one N-vinylcarboxamide of the formula in which R1 and R2 are H or C1- to C6 alkyl, (b) at least one monoethylenically unsaturated monomer comprising acid groups, and/or the alkali metal, alkaline earth metal or ammonium salts thereof, and if appropriate (c) other monoethylenically unsaturated monomers, and if appropriate (d) compounds having at least two ethylenically unsaturated double bonds in their molecule.

Abstract: Methods of producing vinyllactam copolymers which include: providing at least one water-soluble N-vinyllactam; providing at least one hydrophobic comonomer; and subjecting the at least one water-soluble N-vinyllactam and the at least one hydrophobic comonomer to free-radical polymerization in an organic solvent in the presence of an initiator, under a combination of process measures selected from the group consisting of A and B; wherein: (A) comprises (i) polymerization under reflux, and at least two of (ii), (iii), (iv), (v), (vi), and (vii), wherein (ii) comprises an addition of at least 5 mol % of N-vinyllactam to the polymerization mixture if at least 70 mol % of the total amount of hydrophobic monomer used have completely reacted, (iii) comprises return of condensate formed in the reflux from below to the polymerization mixture, (iv) comprises introduction of the initiator in the form of a solution in an organic solvent from below into the polymerization mixture, (v) comprises addition of N-vinyllactam t

Abstract: Aqueous solutions comprising: one or more polymeric components selected from the group consisting of homopolymers of N-vinylpyrrolidone, copolymers of N-vinylpyrrolidone, and mixtures thereof; and hydrogen peroxide; wherein the hydrogen peroxide is present in an amount of 100 to 5000 ppm; and methods of stabilizing aqueous solutions containing one or more polymeric components selected from the group consisting of homopolymers of N-vinylpyrrolidone, copolymers of N-vinylpyrrolidone, and mixtures thereof.

Abstract: Method of producing copolymers by free-radical polymerization of at least one water-soluble N-vinyllactam and at least one hydrophobic comonomer in an organic solvent in the presence of an initiator, where the polymerization is carried out under a gauge pressure such that evaporation of the components is avoided.

Abstract: The present invention relates to an aqueous composition comprising at least one finely divided filler and at least one water-soluble amphoteric copolymer, a process for the preparation of such a composition and its use as an additive in the production of paper, cardboard and board.

Abstract: The present invention relates to an aqueous composition comprising at least one finely divided filler and at least one water-soluble amphoteric copolymer, a process for the preparation of such a composition and its use as an additive in the production of paper, cardboard and board.

Abstract: Aqueous slurries of finely divided fillers which are at least partly coated with polymers and which are obtainable by treating aqueous slurries of finely divided fillers with at least one water-soluble amphoteric copolymer which is obtainable by copolymerization of (a) at least one N-vinylcarboxamide of the formula ?where R1 and R2 are H or C1- to C6-alkyl, (b) at least one monoethylenically unsaturated carboxylic acid having 3 to 8 carbon atoms in the molecule and/or the alkali metal, alkaline earth metal or ammonium salts thereof and, if required, (c) other monoethylenically unsaturated monomers which are free of nitrile groups and, if required, (d) compounds which have at least two ethylenically unsaturated double bonds in the molecule and subsequent partial or complete elimination of the groups —CO—R1 from the monomers III incorporated in the form of polymerized units in the copolymer are used as an additive to the paper stock in the production of filler-containing paper, filler-containing cardboa

Abstract: At least one single-stage or multistage stirrer which produces not only a tangential flow component but also an axial flow field is used in a stirred-vessel reactor in connection with the preparation of polymers by liquid phase polymerization.

Abstract: An aqueous polymer dispersion with a solids volume concentration of at least 50% by volume is obtainable by polymerizing monomers by the method of free radical aqueous emulsion polymerization with the addition of at least one fine and at least one coarse aqueous starting polymer dispersion.

Abstract: An aqueous polymer dispersion having a solids volume concentration of 50% by volume or more is obtainable by polymerizing radical polymerizable monomers other than vinyl or vinylidene halides by the method of free radical aqueous emulsion polymerization with the addition of an aqueous starting polymer dispersion having a certain diameter distribution of the starting polymer particles present therein by the stream addition process.

Abstract: An aqueous polymer dispersion with a final solids volume concentration of at least 50% by volume is obtainable by polymerizing at least one radical polymerizable monomer by the method of free radical aqueous emulsion polymerization with the addition of an aqueous dispersion of a starting polymer.

Abstract: An aqueous polymer dispersion with a final solids volume concentration of at least 50% by volume is obtainable by polymerizing at least one radical polymerizable monomer by the method of free radical aqueous emulsion polymerization with the addition of an aqueous dispersion of a starting polymer.

Abstract: An aqueous polymer dispersion with a solids volume concentration of at least 50% by volume is obtainable by polymerizing monomers by the method of free radical aqueous emulsion polymerization with the addition of at least one fine and at least one coarse aqueous starting polymer dispersion.

Abstract: An aqueous polymer dispersion with a solids volume concentration of at least 50% by volume is obtainable by polymerizing monomers by the method of free radical aqueous emulsion polymerization with the addition of at least two starting polymer dispersions, of which one contains not only particularly finely divided but also coarsely divided polymer particles.