Abstract: A method for manufacturing a multi-layered paperboard is disclosed, which includes at least two fibrous layers, in which method at least one layer of the multi-layered paperboard is treated by applying an aqueous solution of a first strength component in dissolved form including anionic strength polymer and/or amphoteric strength polymer composition on a surface of layer, and an aqueous solution of a cationic second strength component in dissolved form is added to a fibre stock from which at least one of the fibrous layers joined together is formed.

Abstract: A method is disclosed for treating aqueous feed by dissolved gas flotation. The aqueous feed originates from industrial processing of fibrous material, where the aqueous feed includes an aqueous phase and solid particulate material suspended in the aqueous phase. The method includes bringing a flocculant in contact with the aqueous feed, flocculating suspended solid particulate material into flocs and contacting formed flocs with gas bubbles and inducing their flotation in a flotation basin. The flocculant includes a polymer composition having a charge density of at the most 1.7 meq/g dry and the polymer composition includes a cationic synthetic first polymer having a charge density at least 1.0 meq/g dry at pH 2.8, and at least one second polymer obtained by polymerization of (meth)acrylamide, the second polymer being polymerized in presence of the cationic first polymer, where the first polymer has a higher charge density than the second polymer.

Abstract: A method is disclosed for dewatering of sludge from a pulp, paper or board making process, such as deinking sludge, including obtaining of an aqueous sludge including an aqueous phase and a fibre material suspended in the aqueous phase. The sludge is subjected to a pre-thickening step, where a first part of the aqueous phase is removed from the sludge and to a pressing step, where a second part of the aqueous phase is removed from the sludge, thereby obtaining a dry pressed sludge. Before or at the pre-thickening step a polymer composition having a charge density of at the most 1.7 meq/g, preferably at most 1.5 meq/g, more preferably at most 1.1 meq/g, is added to the sludge.

Abstract: A method for producing an aqueous copolymer solution, which comprises dissolving a copolymer of (meth)acrylamide and at least 1 mol-% cationic monomers, calculated from total amount of monomers in the dissolving water having calcium hardness of at least mg/l, expressed as Ca2+, and adding acid comprising monoprotic organic acid and/or mineral acid to the dissolving water and/or the aqueous solution of the copolymer in an amount sufficient to provide the aqueous solution of the copolymer with a pH of equal to or less than 4.5. The invention also relates to uses of the obtained polymer solutions in manufacturing of paper, board or the like or in treatment of sludge or water.

Abstract: The present invention relates to a method for providing a pretreated filler composition for use in paper and board manufacturing including the steps of: a) providing a filler comprising precipitated calcium carbonate, said filler being in the form of a slurry comprising no additives; b) providing at least one polymer selected from polyvinylamine or polyacrylic amide, said polymer having a charge density of an absolute value of at most 4 meq/g determined at pH 7; c) combining said at least one polymer of step b) with the filler of step a); d) providing a slurry of nanofibrillar cellulose; e) combining said nanofibrillar cellulose slurry with the formed combination of step c) and forming a pretreated filler composition comprising aggregates. Further it also relates to a pretreated filler composition prepared therefrom, and its use in stocks, paper and paper board.

Abstract: A polymer composition includes a first host polymer, which is a copolymer of (meth)acrylamide and at least one cationic first monomer, and a second polymer, which is a copolymer of (meth)acrylamide and at least one cationic second monomer. The second polymer is polymerised in presence of the first host polymer, and the first host polymer has a higher cationicity than the second polymer, the difference in cationicity of the first host polymer and the second polymer being at least 3 mol-%, at least 5 mol-%, more preferably at least 7 mol-%. The polymer composition has a standard viscosity of >2.0 mPas, measured at 0.1 weight-% solids content in an aqueous NaCl solution (1 M), at 25° C., using Brookfield VII T viscometer with UL adapter. The invention relates also to uses of said polymer composition.

Abstract: A method for manufacture of paper, board or the like, comprising the step of dissolving a composition into aqueous solution, whereby an aqueous treatment solution is obtained for adding the obtained treatment solution to the pulp. The composition comprising a copolymer of acrylamide and at least one cationic monomer, the copolymer comprising cationic monomers at least 15 mol-%, calculated from total amount of monomers, and an ionic crosslinker agent comprising at least two carboxyl groups, wherein the equivalent ratio of carboxyl groups:cationic monomer is between 1:20 and 1:0.5.

Abstract: The invention relates to an aqueous dry strength composition suitable for use in manufacture of paper, board or the like. The composition includes a mixture of a synthetic polymer component, which is a copolymer of acrylamide and at least one anionic monomer, and a cationic starch component. The polymer component has an anionicity of 1-60 mol-%. The synthetic polymer component and cationic starch component provide the composition with a charge density in the range of 0.05-1 meq/g, when measured at pH 2.8, and 0.2-?3 meq/g, when measured at pH 7.0. The invention also relates to a method for making of paper, board or the like, where the dry strength composition is diluted with water, and the solution of the dry strength composition is added to the fibre stock before or after the addition of a cationic strength agent.

Abstract: Drainage and press dewatering system for manufacture of paper, board or the like, comprising (a) amphoteric polyacrylamide, which is a copolymer obtained by polymerizing (meth)acrylamide and 1-80 mol-% of cationic monomers and/or 0.1-70 mol-% of anionic monomers, the polyacrylamide having an intrinsic viscosity in the range of 6-38 dl/g, (b) inorganic microparticles of siliceous material, such as colloidal silica or bentonite, and (c) a high-charged cationic coagulant having a charge density over 5 meq/g and preferably over 6 meq/g determined at pH 6 and selected from aluminium based coagulants, organic polymers and mixtures thereof.

Abstract: The invention relates to a method and treatment system for making of paper or surface ply of a multi-ply board from a fibre suspension, where at least 90 weight-% of fibres originate from chemical pulping process, chemi-thereto mechanical pulping process and/or office waste deinking pulping process. The fibre suspension further comprises inorganic mineral particles and cationic starch. A cationic copolymer of acrylamide and cationic monomers is incorporated to the fibre suspension and it is allowed to interact by flocculation with at least some of the said components of the fibre suspension. An anionic copolymer of acrylamide and more than 30 mol-% of anionic monomers is added to the fibre suspension, and fibre suspension is formed into a fibre web and drying the web to a dryness of at least 80%. An aqueous surface composition comprising polymeric binder is applied on the surface of the web.

Abstract: The invention relates to a method for treating starch in pulp, paper and board making processes, in which processes recycled fibre material is used as raw material wherein the recycled fibre material is pulped in a pulper and obtaining a pulp flow comprising an aqueous phase and at least recycled fibres and starch dispersed in the aqueous phase. The method comprising the following steps: —adding amylase enzyme inhibitor and/or at least one biocide to pulp flow or to an aqueous process flow comprising starch for preventing starch degradation, and—adding an amphoteric polymer obtained by copolymerisation of (meth)acrylamide with cationic and anionic monomers to pulp flow or to an aqueous process flow comprising starch for binding starch to the fibres.

Abstract: The invention relates to a water-soluble polymer product in particle form, comprising amphoteric polyacrylamide, which is obtained by gel polymerisation of acrylamide together with anionic and cationic monomers. The amphoteric polyacrylamide has a mass average molecular weight MW of 1 500 000-6 000 000 g/mol, and a total ionicity of 4-15 mol-%, whereby the polymer product has a polymer content of at least 60 weight-%. The invention relates also to uses of the polymer product in paper and board making.

Abstract: The present invention relates to an interpenetrating polymer network (IPN) material comprising microcrystalline cellulose (MCC), microfib-rillated cellulose (MFC) or a mixture thereof, and at least one polymer forming an IPN together with the MCC, MFC or mixture thereof. The present invention further relates to a process for producing the IPN material, and to use of the IPN material in paper industry.

Abstract: A cationic glyoxylated polyacrylamide polymer composition having improved storage stability for use in manufacture of paper, board or the like, which aqueous composition includes a glyoxylated polyacrylamide polymer having a cationic charge density in a range of 0.8-1.8 meq/g of dry polymer in dry content of 5-15% and a buffering acid. The aqueous composition has pH in a range of 2.2-4.0 and a viscosity of less than 80 mPas measured at 25° C. by using a Brookfield viscometer after 30 days storage at 35° C. or after 60 days storage at 23° C.

Abstract: A method is disclosed for increasing strength properties, preferably burst strength and SCT strength, of a paper or board product. The paper or board product is manufactured from a fibrous web produced by a multilayer headbox, where an aqueous layer is formed between at least a first and a second fibre layer formed from fibrous stock suspension(s), and where feed water for the aqueous layer includes at least one cationic polymer. The method of the invention includes adding an anionic additive selected from a group comprising anionic synthetic organic polymers, anionic polysaccharides, and any of their combinations to the feed water before formation of the aqueous layer.

Abstract: The present invention relates to an interpenetrating polymer network (IPN) material comprising a copolymer of vinylamine-vinylformamide, and a homo-polymer or a copolymer of at least one monomer selected from acrylamide or derivatives thereof, acrylic acid or derivatives thereof, or a mixture thereof forming the IPN material together with the copolymer of vinylamine-vinyl-formamide. The present invention further relates to a process for producing the IPN material, and to use of the IPN material in paper industry.

Abstract: A method is disclosed for dewatering of sludge from a pulp, paper or board making process, such as deinking sludge, including obtaining of an aqueous sludge including an aqueous phase and a fibre material suspended in the aqueous phase. The sludge is subjected to a pre-thickening step, where a first part of the aqueous phase is removed from the sludge and to a pressing step, where a second part of the aqueous phase is removed from the sludge, thereby obtaining a dry pressed sludge. Before or at the pre-thickening step a polymer composition having a charge density of at the most 1.7 meq/g, preferably at most 1.5 meq/g, more preferably at most 1.1 meq/g, is added to the sludge.

Abstract: The present invention relates to a device, system and method to measure tackiness of a substance, such as pulp, with an on-line or an in-line sensor having a transparent plate with a surface where tacky particles can attach. Attached particles are identified by a camera behind the plate. The camera is focused to detect stationary particles attached to the surface. Measurement is performed directly from a process stream or from a sidesteam and the plate does not need to be removed from the process for the measurement. The plate material may be plastic, such as polycarbonate or acrylic. Additionally, the flow speed may be kept be low, e.g. <0.1 m/s at the measurement position, and/or there may be a stagnation point of flow at or near measurement where the flow speed approaches zero.

Abstract: A polymer composition includes a first host polymer, which is a copolymer of (meth)acrylamide and at least one cationic first monomer, and a second polymer, which is a copolymer of (meth)acrylamide and at least one cationic second monomer. The second polymer is polymerised in presence of the first host polymer, and the first host polymer has a higher cationicity than the second polymer, the difference in cationicity of the first host polymer and the second polymer being at least 3 mol-%, at least 5 mol-%, more preferably at least 7 mol-%. The polymer composition has a standard viscosity of >2.0 mPas, measured at 0.1 weight-% solids content in an aqueous NaCl solution (1 M), at 25° C., using Brookfield VII T viscometer with UL adapter. The invention relates also to uses of said polymer composition.

Abstract: The invention relates to a composition for sizing of a surface of paper, board or the like and its use for increasing strength properties of paper, board or the like. The composition has a solids content of 3-30%, and it comprises degraded non-ionic starch, and at least 0.5 weight-% of anionic polyacrylamide, which has a molecular weight, MW, >500 000 g/mol and <2 500 000 g/mol and an anionicity in the range of 4-35 mol-%. The invention further relates also to a method for producing paper, board or the like, which comprises addition of a first strength composition, which comprises a cationic agent, to a fiber stock, formation of a fibrous web from the fiber stock, drying of the fibrous web to dryness of at least 60%, and application of a second strength composition, which comprises an anionic hydrophilic polymer and a starch component, on the surface of the fibrous web.