An object is to optimize a bleaching process in a step of producing phosphorylated cellulose fibers. A pulp comprises cellulose fibers having 0.5 mmol/g or more of phosphoric acid groups or phosphoric acid group-derived substituents, when the pulp is processed into a sheet and four sheets are laminated on one another, the ISO whiteness of the laminate is 82% or more. Moreover, when the pulp is processed into a sheet and four sheets are then laminated on one another, the b* value of the obtained laminate according to the L*a*b* color system is 5.5 or less.

A process is provided for making a fluff pulp sheet, comprising contacting at least one cationic trivalent metal, salt thereof, or combination thereof with a composition comprising fluff pulp fibers and water at a first pH, to form a fluff pulp mixture; forming a web from the fluff pulp mixture; and applying at least one debonder surfactant to the web and raising the pH to a second pH, which is higher than the first pH, to make the fluff pulp sheet. A fluff pulp sheet is also provided, comprising a web comprising fluff pulp fibers; at least one cationic trivalent metal, salt thereof, or combination thereof; at least one debonder surfactant; and a fiberization energy of <145 kJ/kg. Products and uses of the fluff pulp sheet are also provided.

A method for making a specialty fiber by activating pulp in an alkaline aqueous medium, then reacting it a water-soluble, multi-functional reagent able to bridge neighboring cellulose chain within a single fiber. The resultant specialty cellulose fibers have high intrinsic viscosity and may be used to make cellulose ethers, cellulose acetate, and viscose.

The invention relates to the chemical industry, namely to the production method of cellulose from all types of plant cellulose-containing raw material. The method includes raw material impregnation and hydrolysis in a hydrolysis solution, cellulose filtration, washing with water, filtration and drying, accompanied with the use of cycles that include heating of the material to a temperature of 115° C. or less, high-speed impulse action of vacuum with a pressure change in the range up to 5 mm Hg for a time of less than 10 seconds, followed by exposure under vacuum and vacuum relief.

Both solution of nitric or sulphuric acids, their mixture and alkaline solution can be used as hydrolysis solution.

Technical result of the claimed method consists in. reducing the duration of the cellulose hydrolysis process, reducing the temperature of the processes while obtaining the required chemical and structural homogeneity of the cellulose.

A method for manufacturing paper is disclosed. A pulp slurry is produced, a paper sheet is formed from the slurry, an aldehyde functionalized polymer or polymers in combination with at least one additional strength additive is added to the slurry before and/or after sheet formation, and a water soluble acid is added on the paper sheet.

A method of producing nanocellulose includes defibrillating cellulosic raw material by oxidation with an oxidant such as NaClO or H202 and sonication in the presence of a swelling agent. The nanocellusose produced by the method can be used in a method of recycling cellulosic material such as paper, card, cardboard or wood to produce recycled paper.

A process for recovery of lignin from black liquor that contains either soluble or dispersed lignin by generating a “liquid lignin” at high yield is disclosed. Soluble lignin at a high pH is precipitated by reducing the pH of the black liquor stream by countercurrent reaction with carbon dioxide, at elevated temperature and pressure, creating a dense liquid-lignin phase and a light lignin-depleted phase. The dense lignin-rich phase is separated and washed countercurrently with a non-sulfur containing acid, such as acetic acid or formic acid, to displace metal cations from the lignin, creating a low-salt lignin, which is then formed into a low-dust, high-bulk density lignin fuel pellet. If desired, an oxidation step may be used to eliminate odor for lignins having high value green chemistry applications.

The present invention relates to surface-mineralized organic fibers comprising organic fibers having a length in the millimeter range, the surface of which is at least partially coated with finely divided alkaline earth carbonate nanoparticles by means of binders based on copolymers comprising as monomers one or more dicarboxylic acids and one or more monomers from the group of diamines, triamines, dialkanolamines or trialkanolamines and epichlorohydrin, a method for producing such surface-mineralized organic fibers, aqueous slurries thereof, their use in papermaking, in surface finishing of paper, plastic, cement and clay surfaces, in paints and varnishes and the use of the inventive binders for coating the organic fibers with nano alkaline earth carbonates.

Provided is a carboxymethylated microfibrillated cellulose fiber having a Canada standard freeness of less than 200 mL and an average fiber diameter of not less than 500 nm. Said fiber provides a composition having excellent water retention ability.

The present disclosure relates to a method for preparing an unbleached biomechanical pulp and fully utilizing by-products by treating wheat straws with heat steam in synergy with biological enzymes, which belongs to the technical field of papermaking technology and waste comprehensive utilization. The present disclosure provides a method for preparing an unbleached biomechanical pulp by treating whole wheat straws with heat steam in synergy with biological enzymes, where the prepared high-strength biomechanical pulp can meet the requirements of producing unbleached packaging paper and paper-based materials. At the same time, the by-products are recycled to prepare a biomass compound fertilizer, which turns solid waste into treasure and realizes the high-value full utilization of wheat straw. Therefore, the method in the present disclosure is simple, green, clean and efficient, which has good practical application value and broad application prospects.