Abstract:
A method for manufacturing a sheet of paper and/or board having improved retention and drainage properties is provided, according to which, before the formation of the sheet and/or board, at least two retention aids are added to the fibrous suspension. These two retention aids are a main retention aid corresponding to a (co)polymer having a cationic charge density above 2 meq/g, obtained by the Hofmann degradation reaction, and a secondary retention aid corresponding to a water-soluble or water-swellable polymer having an anionic charge density above 0.1 meq/g. The main retention aid is introduced into the fibrous suspension in a proportion of 100 to 800 g/t of dry pulp, and the secondary retention aid is introduced into the fibrous suspension in a proportion of 50 to 800 g/t of dry pulp and has an intrinsic viscosity IV above 3 dl/g.
Abstract:
A method for producing paper, cardboard or similar materials, comprising, separately or in a mixture, adding to a fibrous suspension: at least one main retention agent comprising a cationic (co)polymer, and at least one dual retention agent comprising a crosslinked cationic (co)polymer obtained in the form of a dispersion and placed in solution prior to its introduction into the fibrous suspension with gentle stirring. The crosslinked cationic (co)polymer having—a UL viscosity of between 1.3 and 2.7 cps, preferably between 1.5 and 2.4 cps, and—an apparent cationicity ratio of between 25 and 75%. Optionally, before or after the dual agent or the main retention agent are added, one or more tertiary retention agent(s) selected from the group comprising mineral particles and organic polymers carrying anionic charges, is added to the suspension.
Abstract:
A process for the manufacture of paper, board or similar products, comprises first of all, adding, to the paper pulp fibrous suspension, at least one main retention aid composed of a cationic (co)polymer. Then optionally the flocs obtained are sheared. Subsequently there is added to the suspension, separately or as a mixture, in any order: at least one secondary retention aid chosen from the group consisting of silica derivatives and anionic or amphoteric organic polymers, and at least one tertiary retention aid composed of a crosslinked anionic organic polymer with a size of greater than or equal to 1 micrometer and exhibiting an intrinsic viscosity of less than 3 dl/g.
Abstract:
A method for manufacturing a sheet of paper and/or board having improved retention and drainage properties is provided, according to which, before the formation of the sheet and/or board, at least two retention aids are added to the fibrous suspension. These two retention aids are a main retention aid corresponding to a (co)polymer having a cationic charge density above 2 meq/g, obtained by the Hofmann degradation reaction, and a secondary retention aid corresponding to a water-soluble or water-swellable polymer having an anionic charge density above 0.1 meq/g. The main retention aid is introduced into the fibrous suspension in a proportion of 100 to 800 g/t of dry pulp, and the secondary retention aid is introduced into the fibrous suspension in a proportion of 50 to 800 g/t of dry pulp and has an intrinsic viscosity IV above 3 dl/g.
Abstract:
A method for producing paper, cardboard or similar materials, comprising, separately or in a mixture, adding to a fibrous suspension: at least one main retention agent comprising a cationic (co)polymer, and at least one dual retention agent comprising a crosslinked cationic (co)polymer obtained in the form of a dispersion and placed in solution prior to its introduction into the fibrous suspension with gentle stirring. The crosslinked cationic (co)polymer having—a UL viscosity of between 1.3 and 2.7 cps, preferably between 1.5 and 2.4 cps, and—an apparent cationicity ratio of between 25 and 75%. Optionally, before or after the dual agent or the main retention agent are added, one or more tertiary retention agent(s) selected from the group comprising mineral particles and organic polymers carrying anionic charges, is added to the suspension.
Abstract:
A process for the manufacture of paper, board or similar products, comprises first of all, adding, to the paper pulp fibrous suspension, at least one main retention aid composed of a cationic (co)polymer. Then optionally the flocs obtained are sheared. Subsequently there is added to the suspension, separately or as a mixture, in any order: at least one secondary retention aid chosen from the group consisting of silica derivatives and anionic or amphoteric organic polymers, and at least one tertiary retention aid composed of a crosslinked anionic organic polymer with a size of greater than or equal to 1 micrometer and exhibiting an intrinsic viscosity of less than 3 dl/g.