Packaging paper consisting of an unbleached kraft paper with a kappa value according to ISO 302:2015 between 38 and 60, preferably between 40 and 58 as base paper, which is optionally coated on at least one side, wherein the kraft paper is made of at least 90% primary pulp, has a basis weight according to ISO 536:2019 between 60 g/m.sup.2 and 150 g/m.sup.2 and an air resistance according to ISO 5636-5:2013 (Gurley) between 5 and 30 seconds, wherein the base paper has an elongation at break in the machine direction according to ISO 1924-3:2005 between 2.5% and 8.5% and has a Bendtsen roughness according to ISO 8791-2:2013 between 70 ml/min and 600 ml/min, preferably between 150 ml/min to 550 ml/min, more preferably 200 ml/min to 500 ml/min, and process for its production.

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 Ca.sup.2+, 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.

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 Ca.sup.2+, 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.

Described herein is an aqueous composition to improve barrier properties. Particularly, described herein is a polymer-based grease resistant aqueous composition for coating paper and paper products.

Described herein is an aqueous composition to improve barrier properties. Particularly, described herein is a polymer-based grease resistant aqueous composition for coating paper and paper products.

A water-dispersible composite structure, which comprises one or more layers, and a method of producing the same. At least a part of the layers is formed by a fibrous web or sheet containing 50-90 parts by weight of wood fibers and 10-90 parts by weight of annual or perennial plant fibers and/or 10-50 parts by weight of synthetic short-cut fibers, and 0.1-20% by weight of a binder, calculated from the weight of the fibers, and at least a part of the binder being a water-soluble polymer and another part a water dispersible binder, and the fibrous sheet or web being produced by wet forming. By means of the invention, the fibers of the composite structure can be recovered and recycled by equipment conventionally used in the paper and paperboard industry.

A water-dispersible composite structure, which comprises one or more layers, and a method of producing the same. At least a part of the layers is formed by a fibrous web or sheet containing 50-90 parts by weight of wood fibers and 10-90 parts by weight of annual or perennial plant fibers and/or 10-50 parts by weight of synthetic short-cut fibers, and 0.1-20% by weight of a binder, calculated from the weight of the fibers, and at least a part of the binder being a water-soluble polymer and another part a water dispersible binder, and the fibrous sheet or web being produced by wet forming. By means of the invention, the fibers of the composite structure can be recovered and recycled by equipment conventionally used in the paper and paperboard industry.

Grafted, crosslinked cellulosic materials include cellulose fibers and polymer chains composed of at least one monoethylenically unsaturated acid group-containing monomer (such as acrylic acid) grafted thereto, in which one or more of said cellulose fibers and said polymer chains are crosslinked (such as by intra-fiber chain-to-chain crosslinks). Some of such materials are characterized by a wet bulk of about 10.0-17.0 cm3/g, an IPRP value of about 1000 to 7700 cm2/MPa.Math.sec, and/or a MAP value of about 7.0 to 38 cm H2O. Methods for producing such materials may include grafting polymer chains from a cellulosic substrate, followed by treating the grafted material with a crosslinking agent adapted to effect crosslinking of one or more of the cellulosic substrate or the polymer chains. Example crosslinking mechanisms include esterfication reactions, ionic reactions, and radical reactions, and example crosslinking agents include pentaerythritol, homopolymers of the graft species monomer, and hyperbranched polymers.

Grafted, crosslinked cellulosic materials include cellulose fibers and polymer chains composed of at least one monoethylenically unsaturated acid group-containing monomer (such as acrylic acid) grafted thereto, in which one or more of said cellulose fibers and said polymer chains are crosslinked (such as by intra-fiber chain-to-chain crosslinks). Some of such materials are characterized by a wet bulk of about 10.0-17.0 cm3/g, an IPRP value of about 1000 to 7700 cm2/MPa.Math.sec, and/or a MAP value of about 7.0 to 38 cm H2O. Methods for producing such materials may include grafting polymer chains from a cellulosic substrate, followed by treating the grafted material with a crosslinking agent adapted to effect crosslinking of one or more of the cellulosic substrate or the polymer chains. Example crosslinking mechanisms include esterfication reactions, ionic reactions, and radical reactions, and example crosslinking agents include pentaerythritol, homopolymers of the graft species monomer, and hyperbranched polymers.

A softener composition for use in the manufacture of paper includes a softener and an acidic material, wherein the softener composition has a relative acidity (RA) value of more than 0.05.