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%.

Methods and compositions useful for improving drainage in a fluff pulp drying process are provided. The methods and compositions comprise alkyl ether sulfate and ethylene oxide/propylene oxide copolymer. In particular, the methods and compositions can improve drainage of fluff pulp in fluff pulp drying processes.

[Object] An object is to provide a sulfonated fine cellulose fiber having excellent transparency, a sulfonated pulp fiber suitable for the sulfonated fine cellulose fiber, a method for producing these fibers, and a derivative pulp containing the sulfonated pulp fiber.

[Means for achieving the object] The sulfonated pulp fiber of the present invention is a pulp fiber comprising a plurality of cellulose fibers, wherein a part of hydroxyl groups of the cellulose fibers of the pulp fiber is substituted with sulfo groups, an introduction amount of sulfur attributable to the sulfo groups is adjusted to be higher than 0.42 mmol/g while maintaining a fiber shape, and a water retention value of the pulp fiber is adjusted to 150% or more. Since the sulfonated pulp fiber has a predetermined water retaining property or more while maintaining the fiber shape, the degree of flexibility in handling can be improved.

A pulp mixture includes a lignocellulosic material, water, lignin, an inorganic salt, and a copolymer including two or more structural units chosen from ethylene oxide units, propylene oxide units, (meth)acrylic acid units, ethyl acrylate units, and combinations thereof. The copolymer is free of silicone-containing structural units and the lignin is present in an amount of greater than about 150 ppm, based on a total weight of the pulp mixture.

The present invention provides a novel method for producing carboxymethylated cellulose, the method making it possible to economically obtain a high-transparency cellulose nanofiber dispersion. In the carboxymethylation of cellulose, mercerization is carried out in a solvent comprising mainly water, and then carboxymethylation is carried out in a mixed solvent of water and an organic solvent. A nanofiber dispersion of high-transparency carboxymethylated cellulose can be obtained by defibrating the resulting carboxymethylated cellulose.

A carboxymethylated cellulose having a carboxymethyl substitution of no more than 0.50 and a cellulose I type crystallization of at least 50%. Ideally, the anionization is 0.00-1.00 meq/g. The Schopper-Riegler freeness is ideally at least 60.0 SR. Ideally the ratio of filtration residue is 0%-30% by mass. The viscosity (30 rpm, 25 C.) for an aqueous dispersion having a 1% solid content (w/v) is ideally no more than 10.0 mPa.Math.s.

Methods of forming crosslinked cellulose include mixing a crosslinking agent with an aqueous mixture of cellulose fibers containing little to no excess water (e.g., solids content of 25-55%), drying the resulting mixture to 85-100% solids, then curing the dried mixture to crosslink the cellulose fibers. Systems include a mixing unit to form, from an aqueous mixture of unbonded cellulose fibers having a solids content of about 25-55% and a crosslinking agent, a substantially homogenous mixture of non-crosslinked, unbonded cellulose fibers and crosslinking agent; a drying unit to dry the substantially homogenous mixture to a consistency of 85-100%; and a curing unit and to cure the crosslinking agent to form dried and cured crosslinked cellulose fibers. Intrafiber crosslinked cellulose pulp fibers produced by such methods and/or systems have a chemical on pulp level of about 2-14% and an AFAQ capacity of at least 12.0 g/g.

A method is provided for preparing a fibrous material (preferably a mat or filaments) of crosslinked microfibrillated cellulose. Phosphorylated microfibrillated cellulose is spun into a fibrous material; and then said fibrous material is post-treated (e.g. by heat-treatment) to provide crosslinking between the phosphorylated microfibrillated cellulose. Fibrous materials such as filaments or mats, and hygiene products comprising such materials are also described.

A method of increasing chemical efficiency of chemical additives in a papermaking system includes the steps of providing thick stock pulp comprising soluble lignin, process water, and at least about 2% by weight of cellulosic fiber based on total weight of thick stock pulp, and adding at least one laccase enzyme and at least one organic polymer to the thick stock pulp to reduce the amount of soluble lignin therein. The organic polymer is chosen from cationic polymers, non-ionic polymers and combinations thereof.

A wheat straw pulp, a preparation method therefor, an application thereof, and a method for adjusting the degree of substitution of CMC. The preparation method for the wheat straw pulp comprises the following steps: using water as a medium, performing ultrasonic crushing on wheat straw, performing solid-liquid separation, and collecting the solid to obtain wheat straw pulp, the temperature of the ultrasonic crushing being 25-100 C. In the preparation method, by using water as a medium, wheat straw is dissociated into wheat straw fibers in water in a mild temperature condition by means of ultrasonic crushing accompanied by H2O2. The wheat straw pulp can be used for preparing CMC. By adjusting different technological conditions to adjust the properties of the wheat straw pulp, CMC having different degrees of substitution can be prepared.