Provided is a method of making paper and paperboard. In particular graft copolymers of vinyl monomers and functionalized vinylamine-containing base polymers by Michael addition are added to a paper furnish. The composition can be used alone or in combination with other additives for use in paper making and to improve paper making processes such as paper dry and wet strength properties.

The present invention is directed to products, such as paper and paperboard products, comprising a substrate containing cellulose and top ply comprising microfibrillated cellulose and inorganic particulate, to methods of making such paper and paperboard products, and associated uses of such paper and paperboard products. The microfibrillated cellulose and inorganic particulate material are applied at the stage when the wet substrate is in the process of being formed on the wire of a papermaking machine, thereby avoiding the additional cost of more extensive equipment and machinery as well as in separate drying of a coating. The microfibrillated cellulose facilitates the application of inorganic particulate onto the surface of a wet paper or paperboard substrate when applied thusly, by trapping the inorganic particulate on the surface of the substrate and by giving the composite sufficient strength and a suitable pore structure to make it suitable for printing and other end-use demands.

The present invention is directed to products, such as paper and paperboard products, comprising a substrate containing cellulose and top ply comprising microfibrillated cellulose and inorganic particulate, to methods of making such paper and paperboard products, and associated uses of such paper and paperboard products. The microfibrillated cellulose and inorganic particulate material are applied at the stage when the wet substrate is in the process of being formed on the wire of a papermaking machine, thereby avoiding the additional cost of more extensive equipment and machinery as well as in separate drying of a coating. The microfibrillated cellulose facilitates the application of inorganic particulate onto the surface of a wet paper or paperboard substrate when applied thusly, by trapping the inorganic particulate on the surface of the substrate and by giving the composite sufficient strength and a suitable pore structure to make it suitable for printing and other end-use demands.

Glyoxalated polyacrylamide terpolymers and compositions formulated with them are described. These glyoxalated polyacrylamide terpolymers and compositions thereof, can have extended shelf lives and can be used as additives for papermaking, such as providing improved papermaking retention/drainage, and paper products with improved dry and/or temporary wet strength.

Glyoxalated polyacrylamide terpolymers and compositions formulated with them are described. These glyoxalated polyacrylamide terpolymers and compositions thereof, can have extended shelf lives and can be used as additives for papermaking, such as providing improved papermaking retention/drainage, and paper products with improved dry and/or temporary wet strength.

Methods of producing a multi-ply paper product are provided. The methods comprise applying coagulant and/or hybrid coagulant-flocculant composition to an upper ply substrate disposed adjacent and above a lower ply substrate in an amount such that a portion of the coagulant and/or the hybrid coagulant-flocculant composition passes through the upper ply substrate. Preferably, the lower ply substrate has a greater freeness than the upper ply substrate. The methods of the present disclosure preferably allow for efficient use of RDF chemicals while making use of the innate freeness differences between the upper and lower ply substrates.

Methods of producing a multi-ply paper product are provided. The methods comprise applying coagulant and/or hybrid coagulant-flocculant composition to an upper ply substrate disposed adjacent and above a lower ply substrate in an amount such that a portion of the coagulant and/or the hybrid coagulant-flocculant composition passes through the upper ply substrate. Preferably, the lower ply substrate has a greater freeness than the upper ply substrate. The methods of the present disclosure preferably allow for efficient use of RDF chemicals while making use of the innate freeness differences between the upper and lower ply substrates.

Provided is a method for efficiently producing on an industrial scale a high-performance polyvinylamine solution having good handling properties. After producing a polymer containing N-vinylcarboxamide monomer units having a value of the weight average molecular weight (Mw)/number average molecular weight (Mn) of 5 or higher by aqueous solution standing adiabatic polymerization, the polymer is hydrolyzed in an aqueous solvent in the presence of an alkali and an antigelling agent. In a preferred embodiment of the present invention, a polymer powder having a volatile content of 0.1-12% by mass is obtained by drying and pulverizing after producing a (co)polymer, and the powder obtained is stored or transported to the site of use of the polymer solution and hydrolyzed in an aqueous solvent in the presence of an alkali and an antigelling agent when the polymer solution is needed or at the site of use of the polymer solution.

Provided is a method for efficiently producing on an industrial scale a high-performance polyvinylamine solution having good handling properties. After producing a polymer containing N-vinylcarboxamide monomer units having a value of the weight average molecular weight (Mw)/number average molecular weight (Mn) of 5 or higher by aqueous solution standing adiabatic polymerization, the polymer is hydrolyzed in an aqueous solvent in the presence of an alkali and an antigelling agent. In a preferred embodiment of the present invention, a polymer powder having a volatile content of 0.1-12% by mass is obtained by drying and pulverizing after producing a (co)polymer, and the powder obtained is stored or transported to the site of use of the polymer solution and hydrolyzed in an aqueous solvent in the presence of an alkali and an antigelling agent when the polymer solution is needed or at the site of use of the polymer solution.

The present invention relates to a method for producing a cationic polyvinyl amine based copolymer. The present invention further relates to a cationic polyvinyl amine based copolymer and use of the copolymer in paper industry as a strength agent, a retention agent and a drainage agent.