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.

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.

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 (δ1) and a target pH value (δ2), 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 (δ1) and a target pH value (δ2), 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.

Flame-resistant paper for radio wave absorber members includes 40 to 70% by mass of pulp; 5 to 50% by mass of aluminum hydroxide powder; and 3 to 15% by mass of a flame retardant consisting of a polyborate, wherein the flame retardant consisting of a polyborate is contained in an amount of 7 to 25% by mass relative to the amount of the pulp.

A glyoxylate starch may be formed by dispersing a starch in a liquid to form a starch slurry. The starch may be one or more of a cationic starch, nonionic starch, and an anionic starch. 2-chloracetamide is added to the starch slurry mixture to form a first reaction mixture. The temperature of the first reaction mixture may then be raised, and then cooled to form a modified starch, and glyoxal may be added to the modified starch solution to form a second reaction mixture that may then be stirred to produce a glyoxylate starch.

A glyoxylate starch may be formed by dispersing a starch in a liquid to form a starch slurry. The starch may be one or more of a cationic starch, nonionic starch, and an anionic starch. 2-chloracetamide is added to the starch slurry mixture to form a first reaction mixture. The temperature of the first reaction mixture may then be raised, and then cooled to form a modified starch, and glyoxal may be added to the modified starch solution to form a second reaction mixture that may then be stirred to produce a glyoxylate starch.

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.

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.