A method for forming a thermoplastic composite material in a papermaking machine, wherein the method comprises the steps of: forming an aqueous fiber material suspension; bringing said fiber suspension in contact with at least one additive, said additive being introduced into said fiber suspension, whereby said additive reacts to form a precipitation product onto or into the fibers, thereby forming an intermediate suspension, introducing, after the formation of the intermediate suspension, a plastic material into said intermediate suspension, thereby forming a plastic fiber composite suspension.

A method for manufacturing an extensible paper, is herein described. The method comprises the steps of: providing pulp fibers in form of a pulp having a first length-weighted average curl index; mechanically treating the pulp fibers using a pulp compression process to induce fiber deformations such that the resulting pulp fibers have a second length-weighted average curl index higher than the first length-weighted average curl index; forming a wet web using the mechanically treated pulp fibers; drying the wet web under restraint to form a dried web; and adding a polymer to the dried web. An extensible paper is also described that comprises: pulp fibers having a length-weighted average curl index C.sub.LW; and a polymer in an amount of from 2 to 40 wt % based on the weight of the extensible paper; wherein the extensible paper has a Gurley air resistance below 20 s/100 mL and an elongation at break of at least 7%.

A method for producing an aqueous copolymer solution, which comprises dissolving a copolymer of (meth)acrylamide and at least 1 mol-% cationic monomers, calculated from total amount of monomers in the dissolving water having calcium hardness of at least mg/l, expressed as Ca.sup.2+, and adding acid comprising monoprotic organic acid and/or mineral acid to the dissolving water and/or the aqueous solution of the copolymer in an amount sufficient to provide the aqueous solution of the copolymer with a pH of equal to or less than 4.5. The invention also relates to uses of the obtained polymer solutions in manufacturing of paper, board or the like or in treatment of sludge or water.

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.

A system and method of forming a molded pulp product that involves separately collecting, from a paper-making process, waste water containing short fibers at a first fiber consistency, waste water as dilution water containing fibers at a second fiber consistency that is lower than the first fiber consistency, and water containing long fibers, the long fibers having a length that is greater than a length of the short fibers, blending the waste water containing short fibers and the water containing long fibers to obtain a pulp slurry, and molding the pulp slurry into a molded pulp product at a pulp molding machine. In an embodiment, filtrate removed during the molding of the molded pulp product has a BOD measurement that is 95% less than a BOD measurement of the pulp slurry, where the BOD measurements are obtained using the EPA 405.1, SM5210B Test Method.

The invention relates to a surface treatment composition for paper, board or other fibrous webs. The composition of the invention comprises particles which comprise an active material and a supporting material. The active material comprises a salt or a multivalent metal, such as a divalent or trivalent metal. In accordance with the invention, the supporting material is adapted to release the active material from the particles when subjected to heat and/or pressure and/or a change in pH. Consequently, the active material's adverse effects on the rheology of the composition are avoided while its desired effects on the surface characteristics are retained or enhanced.

A system and method of forming a molded pulp product that involves separately collecting, from a paper-making process, waste water containing short fibers at a first fiber consistency, waste water as dilution water containing fibers at a second fiber consistency that is lower than the first fiber consistency, and water containing long fibers, the long fibers having a length that is greater than a length of the short fibers, blending the waste water containing short fibers and the water containing long fibers to obtain a pulp slurry, and molding the pulp slurry into a molded pulp product at a pulp molding machine. In an embodiment, filtrate removed during the molding of the molded pulp product has a BOD measurement that is 95% less than a BOD measurement of the pulp slurry, where the BOD measurements are obtained using the EPA 405.1, SM5210B Test Method.

A surface treatment composition for paper, board or other fibrous webs. The composition of the invention comprises particles which comprise an active material and a supporting material. The active material comprises a salt of a multivalent metal, such as a divalent or trivalent metal. In accordance with the invention, the supporting material is adapted to release the active material from the particles when subjected to heat and/or pressure and/or a change in pH. Consequently, the active material's adverse effects on the rheology of the composition are avoided while its desired effects on the surface characteristics are retained or enhanced.

A sheet forming binder includes a first powder and a second powder having a larger volume average particle size than the first powder. The proportion of the first powder is 10.0% by mass or more relative to the total mass of the first powder and the second powder.

The present invention relates to a process wherein microfibrillated cellulose (MFC) is mixed with at least two retention aids, selected from a cationic or amphoteric polymer and a microparticle or nanoparticle as a pre-mix before dosing it to the stock in a process for manufacture of a fiber based product.