Compositions and methods related to new wet strength resins are provided. By using functionally-symmetrical cross-linkers and mono-functional modifiers, and separating the steps of reacting a prepolymer with the cross-linkers from the reaction of intermediate cross-linked prepolymer with epichlorohydrin, new wet strength resin products are provided having improved properties.

A strength additive system for manufacturing paper, board, tissue or the like includes preferably as separate components, a cationic strength agent, such as a cationic polymer with aldehyde functional groups, and an anionic copolymer obtained by polymerization of a reaction mixture including (meth)acrylamide and anionic monomers, the standard viscosity of the obtained copolymer being in a range of 1.5-5.0 mPas. A method for manufacturing of a paper, board, tissue or the like is further disclosed.

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.

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.

The invention relates to an aqueous composition comprising (a) polymers having primary amino groups and/or amidine groups to a combined content for these groups of ≧1.5 meq/g of polymer, and (b) 0.01 to 50 mol % of 1,4-cyclohexanedione (b) based on the combined amount of primary amino groups and amidine groups of the polymers,
wherein the pH of the aqueous composition is ≦6,
and further to its use as strength enhancer and to a method of producing paper and board, employment of the aqueous composition and also the paper and board thus obtained.

The invention relates to an aqueous composition comprising (a) polymers having primary amino groups and/or amidine groups to a combined content for these groups of ≧1.5 meq/g of polymer, and (b) 0.01 to 50 mol % of 1,4-cyclohexanedione (b) based on the combined amount of primary amino groups and amidine groups of the polymers,
wherein the pH of the aqueous composition is ≦6,
and further to its use as strength enhancer and to a method of producing paper and board, employment of the aqueous composition and also the paper and board thus obtained.

A dry strength composition for manufacture of paper, board or the like is disclosed. The dry strength composition includes, as a mixture, at least one anionically derivatized polysaccharide, and cationic starch having an amylopectin content ≥80 weight-%. The anionically derivatized polysaccharide and the cationic starch provide the composition with a charge density in a range of 0.1-1.5 meq/g, when measured at pH 2.8, and −0.1-−3 meq/g, preferably −0.3-−2.5 meq/g, more preferably −0.5-−2.0 meq/g, when measured as an aqueous solution, at pH 7.0. Further disclosed are a use of the composition and a method for manufacturing paper, board or the like.

A dry strength composition for manufacture of paper, board or the like is disclosed. The dry strength composition includes, as a mixture, at least one anionically derivatized polysaccharide, and cationic starch having an amylopectin content ≥80 weight-%. The anionically derivatized polysaccharide and the cationic starch provide the composition with a charge density in a range of 0.1-1.5 meq/g, when measured at pH 2.8, and −0.1-−3 meq/g, preferably −0.3-−2.5 meq/g, more preferably −0.5-−2.0 meq/g, when measured as an aqueous solution, at pH 7.0. Further disclosed are a use of the composition and a method for manufacturing paper, board or the like.

A polymeric structure, which is obtained by polymerisation of (meth) acrylamide and at least one charged monomer in a polymerisation medium comprising at least a first host polymer, which first host polymer comprises polyvinyl alcohol. The polymeric structure may be used in making of paper, board, tissue or the like as a strength agent, or in dewatering of sludge.

Described are compositions for use in paper products including a modified starch, paper products including a modified starch, and methods of making paper products, and the like. The compositions can include a pulp slurry and a modified starch and can include hardwood fibers, softwood fibers, non-wood fibers, or a combination thereof. Provided for are paper products, such as tissue paper, having a basis weight below 150 gsm. Also provided for are methods for making paper products that can include mixing a pulp slurry with an enzymatically modified starch derivative.