The invention relates to a method and treatment system for making of paper or surface ply of a multi-ply board from a fibre suspension, where at least 90 weight-% of fibres originate from chemical pulping process, chemi-thereto mechanical pulping process and/or office waste deinking pulping process. The fibre suspension further comprises inorganic mineral particles and cationic starch. A cationic copolymer of acrylamide and cationic monomers is incorporated to the fibre suspension and it is allowed to interact by flocculation with at least some of the said components of the fibre suspension. An anionic copolymer of acrylamide and more than 30 mol-% of anionic monomers is added to the fibre suspension, and fibre suspension is formed into a fibre web and drying the web to a dryness of at least 80%. An aqueous surface composition comprising polymeric binder is applied on the surface of the web.

A method for dehydrating a dispersion of a chemically modified pulp (oxidized pulp, carboxymethylated pulp, or cationized pulp) obtained by chemically modifying a pulp feedstock, characterized by dehydrating the dispersion of a chemically modified pulp by means of a screw press.

A method for dehydrating a dispersion of a chemically modified pulp (oxidized pulp, carboxymethylated pulp, or cationized pulp) obtained by chemically modifying a pulp feedstock, characterized by dehydrating the dispersion of a chemically modified pulp by means of a screw press.

The present invention relates to cellulose fiber materials containing 0.01 to 0.5% by weight of ammonia compound comprising oxyalkyl radicals consisting of at least 3 carbon atoms which are biodegradable at a degree of at least 60% according the OECD 301F method and a process for producing debonded cellulose fibers.

The present invention relates to cellulose fiber materials containing 0.01 to 0.5% by weight of ammonia compound comprising oxyalkyl radicals consisting of at least 3 carbon atoms which are biodegradable at a degree of at least 60% according the OECD 301F method and a process for producing debonded cellulose fibers.

An object of the present invention is to provide an ultrafine fiber-containing sheet, regarding which wrinkles and/or cracks generated upon sheet formation are suppressed, and a laminate thereof. According to the present invention, provided are: a sheet comprising ultrafine fibers having an ionic substituent and an organic ion that is a counterion of the ionic substituent, wherein the content of the organic ion is 0.40 mmol/g or less; and a laminate comprising the sheet and at least one of an inorganic layer and an organic layer formed on at least one side of the sheet.

An object of the present invention is to provide an ultrafine fiber-containing sheet, regarding which wrinkles and/or cracks generated upon sheet formation are suppressed, and a laminate thereof. According to the present invention, provided are: a sheet comprising ultrafine fibers having an ionic substituent and an organic ion that is a counterion of the ionic substituent, wherein the content of the organic ion is 0.40 mmol/g or less; and a laminate comprising the sheet and at least one of an inorganic layer and an organic layer formed on at least one side of the sheet.