Provided is a powdery paper-strengthening agent comprising an amphoteric (meth)acrylamide-based polymer (A) having a weight-average molecular weight of 1,000,000 to 7,000,000, wherein the amphoteric (meth)acrylamide-based polymer (A) comprises, as constituent monomers, (meth)acrylamide which is an (a1) component, a cationic unsaturated monomer which is an (a2) component, an anionic unsaturated monomer which is an (a3) component, and a crosslinkable unsaturated monomer which is an (a4) component, and wherein an aqueous solution, in which the amphoteric (meth)acrylamide-based polymer (A) is dissolved in a calcium chloride aqueous solution having an electrical conductivity of 4 mS/cm at 25° C. so as to be 1% by weight, has a maximum turbidity of 10 to 2500 NTU at pH 3 to 9.

A drainage-optimized additive composition for papermaking is disclosed. The composition comprises an aqueous media and a glyoxalated polyacrylamide (gPAM) resin having a weight average molecular weight (Mw) of at least about 5 MDa. The composition comprises from about 1.95 to about 2.45 wt. % of the gPAM resin. A method of preparing the composition is also disclosed, and comprises preparing a cationic acrylamide (cAM) prepolymer having at least one predetermined property, and selectively glyoxalating the cAM prepolymer by controlling the concentration of the cAM prepolymer in the aqueous media during glyoxalation in relation to the predetermined property. The method may be carried out in situ during a papermaking process (i.e., as an on-site method). A process of forming paper with the composition also disclosed, and comprises combining the composition with the aqueous suspension of cellulosic fibers, forming the cellulosic fibers into a sheet, and drying the sheet to produce a paper.

The invention relates to a composition for use in a manufacture of paper, board or the like. The composition comprises a mixture of cationic starch having amylopectin content of at least 85%, and an amphoteric polymeric structure comprising structural units originating from non-ionic monomers, preferably (meth)acrylamide, anionic groups and cationic groups, the polymeric structure comprising cationic groups at least 0.2 mol-%.

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 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 manufacturing a fibrous web, such as web of paper, board, tissue or the like is disclosed. The method includes obtaining at least one fibre suspension of lignocellulosic and/or cellulosic fibres and feeding the fibre suspension into an intermediate residence entity. The fibre suspension including bacterial endospores, is discharged out of the intermediate residence entity via an outlet after a residence time of at least 2 hours in the intermediate residence entity and after a time delay the fibre suspension is formed into a fibrous web. Bacterial endospores are sensitized by adding a germinant surfactant including a primary or secondary ammonium head group and a linear unsubstituted C12-alkyl tail, to the fibre suspension at an addition point located at a lower part of the intermediate residence entity or after the outlet of the intermediate residence entity, but before the formation of the fibrous web.

A product includes a microfibrillated cellulose composition, a starch derivative, and an anionic cellulose derivative, as a combined preparation for simultaneous or separate use. The anionic cellulose derivative has a number average molecular weight comprised between 300000 g/mol and 800000 g/mol, and a degree of substitution comprised between 0.3 and 0.65. Additionally, a paper sheet includes the product as an additive to increase the initial wet web strength and/or dry tensile strength of the paper sheet.

A product includes a microfibrillated cellulose composition, a starch derivative, and an anionic cellulose derivative, as a combined preparation for simultaneous or separate use. The anionic cellulose derivative has a number average molecular weight comprised between 300000 g/mol and 800000 g/mol, and a degree of substitution comprised between 0.3 and 0.65. Additionally, a paper sheet includes the product as an additive to increase the initial wet web strength and/or dry tensile strength of the paper sheet.

This invention relates to a method for manufacturing a sheet of paper or cardboard, according to which, before forming said sheet, at least one N-vinylformamide polymer that is partially hydrolyzed in the form of an inverse emulsion is added, at one or more injection points, to a fibrous suspension in the presence of an anti-gelling agent, and having a cationic regain between 30 and 150%, the inverse emulsion having a weight ratio of partially hydrolyzed N-vinylformamide polymer to anti-gelling agent in the range between 1,000,000/5000 and 1,000,000/50,000.

This invention relates to a method for manufacturing a sheet of paper or cardboard, according to which, before forming said sheet, at least one N-vinylformamide polymer that is partially hydrolyzed in the form of an inverse emulsion is added, at one or more injection points, to a fibrous suspension in the presence of an anti-gelling agent, and having a cationic regain between 30 and 150%, the inverse emulsion having a weight ratio of partially hydrolyzed N-vinylformamide polymer to anti-gelling agent in the range between 1,000,000/5000 and 1,000,000/50,000.