Method for producing paper

A method of producing paper and board, said method comprising

• providing an aqueous slurry comprising a filler, at least one water-soluble amphoteric polymer and a microparticle,
• admixing the aqueous slurry to a paper stock,
• dewatering the paper stock by sheet formation in a wire section to obtain a paper sheet, until the paper sheet has a dry matter content of not less than 18 wt %,
• and then pressing the paper sheet and drying,
• wherein the water-soluble amphoteric polymer is obtained by a process comprising
• copolymerizing a monomer mixture comprising
• a) at least one N-vinylcarboxamide of formula
• where R1 and R2 are each independently H or a C1 to C6 alkyl,
• b) at least one monoethylenically unsaturated monomer having at least one free acid group or at least one acid group in salt form,
• c) optionally at least one monoethylenically unsaturated monomer other than said components (a) and (b), and
• d) optionally at least one compound having two or more ethylenically unsaturated double bonds,
• and then partly or wholly hydrolyzing the —CO—R1 groups of the polymer,
• wherein cationic monomer units and anionic monomer units differ in respective molar fractions, each based on a total number of moles of all monomer units, by not more than 10 Mol % in absolute terms;
• wherein the filler is calcium carbonate;
• and
• wherein the microparticle is chosen from:
• a copolymer formed from acrylamide and one or more anionic monomers;
• and/or
• inorganic microparticles of bentonite, colloidal silica, and/or silicate.