The invention relates to a method for pitch control and/or removal during bleaching of cellulosic fibres. Cellulosic fibres are obtained from a pulping process and formed into an aqueous cellulosic fibre suspension, and bleaching of the cellulosic fibre suspension is performed in a bleaching process comprising at least one acidic stage, where pH of the cellulosic fibre suspension is <6. A pitch control agent is added to the cellulosic fibre suspension before the acidic stage, wherein the pitch control agent comprises at least one cationic polymer comprising cationic functional groups which are hydrolysed at pH 9.0

The invention relates to a method for pitch control and/or removal during bleaching of cellulosic fibres. Cellulosic fibres are obtained from a pulping process and formed into an aqueous cellulosic fibre suspension, and bleaching of the cellulosic fibre suspension is performed in a bleaching process comprising at least one acidic stage, where pH of the cellulosic fibre suspension is <6. A pitch control agent is added to the cellulosic fibre suspension before the acidic stage, wherein the pitch control agent comprises at least one cationic polymer comprising cationic functional groups which are hydrolysed at pH 9.0

A modified kraft pulp fiber with unique properties is provided. The modified fiber can be a modified bleached kraft fiber that is almost indistinguishable from its conventional counterpart, except that it has a low degree of polymerization (DP). Methods for making the modified fiber and products made from it are also provided. The method can be a one step acidic, iron catalyzed peroxide treatment process that can be incorporated into a single stage of a multi-stage bleaching process. The products can be chemical cellulose feedstocks, microcrystalline cellulose feedstocks, fluff pulps and products made from them.

A modified kraft pulp fiber with unique properties is provided. The modified fiber can be a modified bleached kraft fiber that is almost indistinguishable from its conventional counterpart, except that it has a low degree of polymerization (DP). Methods for making the modified fiber and products made from it are also provided. The method can be a one step acidic, iron catalyzed peroxide treatment process that can be incorporated into a single stage of a multi-stage bleaching process. The products can be chemical cellulose feedstocks, microcrystalline cellulose feedstocks, fluff pulps and products made from them.

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.

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.

The present invention relates to a high-strength fibre composition comprising fibres up to 7 mm long with a viscosity of between 10 and 20 cP. The fibres present in said composition are distributed according to the length thereof, thereby guaranteeing high strength. The fibre composition according to the invention can also be redispersible. The use of the fibre composition according to the invention and an article comprising said composition are also disclosed.

The present invention relates to a high-strength fibre composition comprising fibres up to 7 mm long with a viscosity of between 10 and 20 cP. The fibres present in said composition are distributed according to the length thereof, thereby guaranteeing high strength. The fibre composition according to the invention can also be redispersible. The use of the fibre composition according to the invention and an article comprising said composition are also disclosed.

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.