Abstract: A process for the production of paper, board and cardboard by draining a paper stock containing interfering substances in the presence of polymers which contain vinylamine units and which have an average molar mass Mw of at least 1 million, a high-consistency stock first being prepared, at least one polymer containing vinylamine units and having an average molar mass Mw of at least 1 million and a degree of hydrolysis of from 1 to 20 mol % being metered into the high-consistency stock, the high-consistency stock being diluted to a low-consistency stock by adding water, and the low-consistency stock being drained, the polymers being hydrolyzed homo- or copolymers of N-vinylcarboxamides additives for reducing deposits in the wire part, press section and drying section of paper machines.

Abstract: A process for the production of paper, board and cardboard by draining a paper stock containing interfering substances in the presence of polymers which contain vinylamine units and which have an average molar mass Mw of at least 1 million, a high-consistency stock first being prepared, at least one polymer containing vinylamine units and having an average molar mass Mw of at least 1 million and a degree of hydrolysis of from 1 to 20 mol % being metered into the high-consistency stock, the high-consistency stock being diluted to a low-consistency stock by adding water, and the low-consistency stock being drained, the polymers being hydrolyzed homo- or copolymers of N-vinylcarboxamides additives for reducing deposits in the wire part, press section and drying section of paper machines.

Abstract: Process for the production of filler-containing papers and filler-containing paper products by addition of an aqueous suspension of at least one finely divided polymer-pigment hybrid to a paper stock and drainage of the paper stock with sheet formation, the polymer-pigment hybrid being obtainable by milling an aqueous suspension of at least one inorganic pigment in the presence of at least one binder and, if appropriate, by drying the aqueous suspension thus obtainable and redispersing the dried polymer-pigment hybrid in water, and the use of the polymer-pigment hybrids thus obtainable as a filler for the production of filler-containing paper or filler-containing paper products.

Abstract: A process for the production of paper, board and cardboard by draining a paper stock containing interfering substances in the presence of polymers which contain vinylamine units and which have an average molar mass Mw of at least 1 million, a high-consistency stock first being prepared, at least one polymer containing vinylamine units and having an average molar mass Mw of at least 1 million and a degree of hydrolysis of from 1 to 20 mol % being metered into the high-consistency stock, the high-consistency stock being diluted to a low-consistency stock by adding water, and the low-consistency stock being drained, and the use of hydrolyzed homo- or copolymers of N-vinylcarboxamides having a degree of hydrolysis of from 1 to 20 mol % and an average molar mass Mw of at least 1 million in the production of paper, board or cardboard as an additive to a high-consistency stock containing interfering substances, for reducing deposits in the wire part, press section and drying section of paper machines.

Abstract: Process for the production of filler-containing papers and filler-containing paper products by addition of an aqueous suspension of at least one finely divided polymer-pigment hybrid to a paper stock and drainage of the paper stock with sheet formation, the polymer-pigment hybrid being obtainable by milling an aqueous suspension of at least one inorganic pigment in the presence of at least one binder and, if appropriate, by drying the aqueous suspension thus obtainable and redispersing the dried polymer-pigment hybrid in water, and the use of the polymer-pigment hybrids thus obtainable as a filler for the production of filler-containing paper or filler-containing paper products.

Abstract: Paper, board and cardboard are produced by shearing the paper stock, adding a microparticle system comprising a cationic polymer and a finely divided inorganic component to the paper stock after the last shearing stage before the head box, draining the paper stock with sheet formation and drying the sheets, by a process in which cationic polyacrylamides, polymers containing vinylamine units and/or polydiallyldimethylammonium chloride having an average molar mass Mw of in each case at least 500 000 Dalton and a charge density of in each case not more than 4.0 meq/g are used as cationic polymers of the microparticle system.

Abstract: A process for the production of paper, board and cardboard by draining a paper stock containing interfering substances in the presence of polymers which contain vinylamine units and which have an average molar mass Mw of at least 1 million, a high-consistency stock first being prepared, at least one polymer containing vinylamine units and having an average molar mass Mw of at least 1 million and a degree of hydrolysis of from 1 to 20 mol % being metered into the high-consistency stock, the high-consistency stock being diluted to a low-consistency stock by adding water, and the low-consistency stock being drained, and the use of hydrolyzed homo- or copolymers of N-vinylcarboxamides having a degree of hydrolysis of from 1 to 20 mol % and an average molar mass Mw of at least 1 million in the production of paper, board or cardboard as an additive to a high-consistency stock containing interfering substances, for reducing deposits in the wire part, press section and drying section of paper machines.

Abstract: Paper, board and cardboard are produced by shearing the paper stock, adding a microparticle system comprising a cationic polymer and a finely divided inorganic component to the paper stock after the last shearing stage before the head box, draining the paper stock with sheet formation and drying the sheets, by a process in which cationic polyacrylamides, polymers containing vinylamine units and/or polydiallyldimethylammonium chloride having an average molar mass Mw of in each case at least 500 000 Dalton and a charge density of in each case not more than 4.0 meq/g are used as cationic polymers of the microparticle system.

Abstract: Paper, board and cardboard are produced by draining a paper stock in the presence of at least one cationic polymer on a wire by a process in which a mixture of at least one substantially linear, cationic polyelectrolyte and an optical brightener is added to the paper stock before sheet formation, said mixture containing at least two parts by weight of the polyelectrolyte per part by weight of the optical brightener.

Abstract: A flow cell through which the sample stream is passed surrounded by an enveloping stream is equipped with a laser-optical measuring means. For use in pressurized systems the inlet of the cell for the enveloping stream medium is connected on the upstream side to a constant pressure and flow means and the outlet from the cell is connected on the downstream side to a regulating means for the sample and enveloping stream flow rate.

Abstract: The maximum amounts of the retention-influencing variable stock components which can be added are determined as a function of a predetermined degree of flocculation and typical values of the stock suspension with the aid of a mathematical relationship, and control signals for metering retention aids are derived from the amounts so that the greatest possible retention can be achieved without exceeding a set-point for the degree of flocculation.