The invention relates to a method for manufacturing a foam-formed cellulosic fibre-material comprising coarse cellulosic fibres a cellulose reinforcement fraction. Furthermore, the invention relates to a foam-formed cellulosic fibre-material, a cellulose bulk sheet for a packaging material and a laminated packaging material comprising the foam-formed cellulosic fibre-material.

A gypsum wallboard panel comprises: a gypsum core; and a paper cover sheet disposed on the gypsum core, the paper cover sheet comprising pulp fiber and an uncooked starch in an amount of at least 2% by weight of the pulp fiber.

There is provided a fiber body manufacturing method including an accumulating step of forming the web by accumulating a material containing fibers and starch or dextrin on the first transport belt by a dry method; a transport step of transporting the web by peeling off a first surface of the web from the first transport belt, and by bringing a second surface of the web, which is a surface opposite to the first surface peeled off from the first transport belt, into contact with the second transport belt; a water-applying step of applying the water to the web which is in contact with the first transport belt or the second transport belt; and a heating step of heating the web by bringing the heating section into contact with the web peeled off from the second transport belt, and forming a fiber body by binding the fibers with the starch or dextrin, in which the web peeled off from the second transport belt is directly supplied to the heating section.

There is provided a fiber body manufacturing method including an accumulating step of forming the web by accumulating a material containing fibers and starch or dextrin on the first transport belt by a dry method; a transport step of transporting the web by peeling off a first surface of the web from the first transport belt, and by bringing a second surface of the web, which is a surface opposite to the first surface peeled off from the first transport belt, into contact with the second transport belt; a water-applying step of applying the water to the web which is in contact with the first transport belt or the second transport belt; and a heating step of heating the web by bringing the heating section into contact with the web peeled off from the second transport belt, and forming a fiber body by binding the fibers with the starch or dextrin, in which the web peeled off from the second transport belt is directly supplied to the heating section.

A binder includes an inorganic particle and a binding material particle containing a binding material to mutually bind fiber by being provided with water, wherein the binder includes a composite particle in which the binding material particle and the inorganic particle are integrated, and a specific surface area of the inorganic particle is 150 m.sup.2/g or more and 280 m.sup.2/g or less.

N-vinyllactam-containing polyvinylamine-based polymers, methods for producing N-vinyllactam-containing polyvinylamine-based polymers, and methods for papermaking are provided. An exemplary method for producing an N-vinyllactam-containing polyvinylamine-based polymer includes performing radical polymerization of a vinylamide monomer, a vinyl monomer containing an amide functional group, and, optionally, a vinyl monomer that contains a carboxylic acid group, to obtain a prepolymer. Further, the method includes hydrolyzing the prepolymer under alkaline conditions to obtain the N-vinyllactam-containing polyvinylamine-based polymer.

A method for manufacture of paper or board, in which method an inverted solution of cationic polymer is added to the fiber suspension for providing retention enhancement without over-flocculating fiber stock and destruction sheet formation and/or improving drainage and enhancing or at least maintaining strength of paper or board, An inverted solution has a bulk viscosity of 50-150 mPas at 0.2 weight-% cationic polymer concentration and inverted solution comprises cationic polymer obtained by reverse phase emulsion polymerization of a monomer blend comprising non-ionic monomers, 15-50 mol-% cationic monomers, an optionally at most 50 ppm of a crosslinking agent, and a chain transfer agent, and the obtained reverse phase emulsion of cationic polymer is inverted into an aqueous solution.

Packaging paper consisting of an unbleached kraft paper with a kappa value according to ISO 302:2015 between 38 and 60, preferably between 40 and 58 as base paper, which is optionally coated on at least one side, wherein the kraft paper is made of at least 90% primary pulp, has a basis weight according to ISO 536:2019 between 60 g/m.sup.2 and 150 g/m.sup.2 and an air resistance according to ISO 5636-5:2013 (Gurley) between 5 and 30 seconds, wherein the base paper has an elongation at break in the machine direction according to ISO 1924-3:2005 between 2.5% and 8.5% and has a Bendtsen roughness according to ISO 8791-2:2013 between 70 ml/min and 600 ml/min, preferably between 150 ml/min to 550 ml/min, more preferably 200 ml/min to 500 ml/min, and process for its production.

Packaging paper consisting of an unbleached kraft paper with a kappa value according to ISO 302:2015 between 38 and 60, preferably between 40 and 58 as base paper, which is optionally coated on at least one side, wherein the kraft paper is made of at least 90% primary pulp, has a basis weight according to ISO 536:2019 between 60 g/m.sup.2 and 150 g/m.sup.2 and an air resistance according to ISO 5636-5:2013 (Gurley) between 5 and 30 seconds, wherein the base paper has an elongation at break in the machine direction according to ISO 1924-3:2005 between 2.5% and 8.5% and has a Bendtsen roughness according to ISO 8791-2:2013 between 70 ml/min and 600 ml/min, preferably between 150 ml/min to 550 ml/min, more preferably 200 ml/min to 500 ml/min, and process for its production.

An object of the present invention is to provide a process for producing fiberous board with which fiberous board exhibiting high bending strength and high stiffness at a wide range of heating temperatures and a wide range of compressing and heating times. In the present invention, fiberous board having an initial flexural modulus of at least 300 MPa in three point bending test is obtained by forming a web by correcting sheath-core composite fibers of which a core component is formed from a copolymer of ethylene glycol and terephthalic acid and the sheath component is formed from ethylene glycol, adipic acid, terephthalic acid, isophthalic acid; and/or diethylene glycol. The web is then compressed in a direction of thickness and heated, so that the sheath component softens and melts and the sheath-core composite fibers are melt bonded together and molded into a flat plate shape.