The invention relates to a strength agent for paper, board or the like. The strength agent comprises a first component, which is refined cellulosic fibres having a refining level of >70° SR, and a second component, which is a synthetic cationic polymer having a charge density of 0.1-2.5 meq/g, determined at pH 2.7, and an average molecular weight of >300 000 g/mol. The invention relates also to a use of the strength agent and to a method for increasing strength properties of paper, board or the like.

The invention relates to a strength agent for paper, board or the like. The strength agent comprises a first component, which is refined cellulosic fibres having a refining level of >70° SR, and a second component, which is a synthetic cationic polymer having a charge density of 0.1-2.5 meq/g, determined at pH 2.7, and an average molecular weight of >300 000 g/mol. The invention relates also to a use of the strength agent and to a method for increasing strength properties of paper, board or the like.

A cellulose based pressboard for insulation in an electrical power transformer, the pressboard includes polyvinylamine (PVAm), and polyacrylamide (PAM), in a combined amount of between 0.01% and 20% by weight of the pressboard.

The invention relates to a method for preparing a dry cationic hydrogel polymer product. The method comprises polymerisation of a reaction mixture comprising ethylenically unsaturated monomers in presence of water and initiator(s) by radical polymerisation and obtaining a hydrogel polymer. The hydrogel polymer is comminuted by chopping or shredding, and dried, whereby a dry hydrogel polymer product in powder form is obtained. At least one cationic reverse phase emulsion polymer is added to the hydro polymer at the comminuting step. The invention relates also to a dry cationic hydrogel polymer composition prepared by the method and its use.

The invention relates to a method for preparing a dry cationic hydrogel polymer product. The method comprises polymerisation of a reaction mixture comprising ethylenically unsaturated monomers in presence of water and initiator(s) by radical polymerisation and obtaining a hydrogel polymer. The hydrogel polymer is comminuted by chopping or shredding, and dried, whereby a dry hydrogel polymer product in powder form is obtained. At least one cationic reverse phase emulsion polymer is added to the hydro polymer at the comminuting step. The invention relates also to a dry cationic hydrogel polymer composition prepared by the method and its use.

The invention relates to a papermaking agent system in liquid form, which comprises (i) cationic starch solution, prepared by cooking a starch mixture comprising a starch component and a water component, and (ii) polymer composition, which has anionic and cationic groups and a cationic net charge of >0.1 meq/g. The polymer composition comprises or originates from at least one of constituents a), b) or c). Constituent a) contains an amphoteric polymer, which is a copolymer comprising structural units derived from acrylamide and/or methacrylamide monomers, and anionic and cationic groups attached to the copolymer. Constituent b) contains a first polymer, which is a copolymer comprising structural units derived from acrylamide and/or methacrylamide monomers, and anionic or cationic groups attached to the copolymer, as well as a second polymer, which comprises groups with opposite charge than the first polymer. Constituent c) contains a third polymer, which comprises a copolymer comprising structural units derived from acrylamide and/or methacrylamide monomers, as well as hydrolytically unstable cationic groups attached to the copolymer. Constituent a), b) or c) is added to one of the components of the starch mixture or to the starch mixture before the cooking of the starch mixture, and/or constituent a) or b) is added to the cationic starch solution after cooking of the starch mixture. The invention relates also to the use of the papermaking agent system and to a method for its preparation.

The present invention relates to a process of manufacturing paper or paperboard which comprises providing (a) a mechanical pulp and (b) a wood free pulp, combining (a) the mechanical pulp and (b) the wood free pulp to form a mixed pulp comprising no more than 20% by total dry weight of fiber of the mechanical pulp, flowing the mixed pulp as a medium consistency stock and combining the medium consistency stock with dilution water to form a low consistency stock, draining the low consistency stock through a wire or mesh to form a sheet of paper which is dried, in which additional filler and a cationic polymer are added to the mechanical pulp.

The present invention relates to a process for producing paper, card and board. The present invention is based on the discovery that controlling solids content during the process in a specified manner provide enhanced initial web strength of the paper prior to drying and allows for higher machine speeds in the paper production process as compared to known processes.

The present invention relates to a process for producing paper, card and board. The present invention is based on the discovery that controlling solids content during the process in a specified manner provide enhanced initial web strength of the paper prior to drying and allows for higher machine speeds in the paper production process as compared to known processes.

The invention relates to fiber sheets, to structures comprising the fiber sheets and to the use of the sheets. The invention further relates to biodegradable and/or recyclable products comprising the fiber sheets, useful in replacing non-biodegradable products.