Preparation of paper, pasteboard, or cardboard involving cutting of the paper pulp, addition of microparticles of cationic polymer, e.g. cationic polyamide, and a finely divided inorganic component after the last cutting step

摘要

A process for preparation of paper, pasteboard, or cardboard involving cutting of the paper pulp, addition of microparticles of cationic polymer, and a finely divided inorganic component after the last cutting step and before pulp swelling, dewatering of the pulp, and sheet formation and drying of the sheets is new. A process for preparation of paper, pasteboard, or cardboard involving cutting of the paper pulp, addition of microparticles of cationic polymer, and a finely divided inorganic component after the last cutting step and before pulp swelling, dewatering of the pulp, and sheet formation and drying of the sheets. The cationic polymer of the microparticle system is cationic polyacrylamide, polymer containing vinylamine units, and/or polydiallyl dimethylammonium chloride containing polymer of mean mol.wt. 500,000 Dalton, and maximum charge density 4.0 meq/g, where the microparticle system free from polymers of charging density (sic) more than 4 meq/g is used as the retention agent.