The invention relates to a method for separating particulates out of filtrates of a paper, cardboard, paperboard or pulp production plant and for reapplying the separated particulates to a surface of paper, cardboard or paperboard, comprising at least the following steps: a) separating the particulates out of the filtrates at a size of less than 1200 pm, b) coagulating the separated particulates of same, c) as applicable, mixing the separated particulates with further particulates from a paper, paperboard or pulp production, and/or microfibrillated cellulose (MFC), d) forming an aqueous suspension from the particulates, e) as applicable, adding to the suspension further additives for the surface treatment of paper or paperboard, selected from native and oxidatively degraded starch or calcium carbonate, f) homogenously applying the formed suspension to a paper or paperboard surface in a quantity between 0.5 and 30 g/m.sup.2, in particular 4 and 15 g/m.sup.2, and g) drying the paper or paperboard.

A method for manufacturing paper is disclosed. A pulp slurry is produced, a paper sheet is formed from the slurry, an aldehyde functionalized polymer or polymers is added to the slurry before and/or after sheet formation, and a water soluble acid is added on the paper sheet.

A method for manufacturing paper is disclosed. A pulp slurry is produced, a paper sheet is formed from the slurry, an aldehyde functionalized polymer or polymers is added to the slurry before and/or after sheet formation, and a water soluble acid is added on the paper sheet.

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.

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.

An on-line control and reaction process for pH adjustment and a control device for automatically adjusting pH value are provided. The process includes mixing a first enhancer and a second enhancer, optionally after diluting the first enhancer and/or the second enhancer with water, to form a mixture, setting a base pH value (1) and a target pH value (2), and adding pH adjuster into the mixture via a pH control unit and mixing to obtain a product with the target pH value. The pH control unit adjusts the adding of the pH adjuster by measuring or inputting certain parameters.

An on-line control and reaction process for pH adjustment and a control device for automatically adjusting pH value are provided. The process includes mixing a first enhancer and a second enhancer, optionally after diluting the first enhancer and/or the second enhancer with water, to form a mixture, setting a base pH value (1) and a target pH value (2), and adding pH adjuster into the mixture via a pH control unit and mixing to obtain a product with the target pH value. The pH control unit adjusts the adding of the pH adjuster by measuring or inputting certain parameters.

Molded pulp article having two or more differing regions in a single layer.

Molded pulp article having two or more differing regions in a single layer.

A method for preparation of a starch-promoted alkyl ketene dimer (AKD) sizing emulsion is provided. The inventive method comprises adding a sizing promoter comprising high-charge cationic starch and polyaluminum chloride (PAC) to a stabilized AKD emulsion and further wherein addition of said sizing promoter comprising high-charge cationic starch and PAC is effected at ambient temperature, after emulsification, stabilization, and homogenization of said stabilized AKD emulsion; and prior to addition of the starch-promoted AKD sizing emulsion to papermaking furnish, pulp, or fiber stock.