A method is provided for preparing a fibrous material of crosslinked microfibrillated cellulose. Dialdehyde microfibrillated cellulose is spun into a fibrous material; said fibrous material is pre- or post-treated (by reduction of pH) to provide crosslinking between the dialdehyde microfibrillated cellulose. Fibrous materials such as filaments or mats, and polymer composites comprising such materials are also described.

A method is provided for preparing a film of crosslinked microfibrillated cellulose. Phosphorylated microfibrillated cellulose is cast or wet-laid into a film; and then said film is post-treated (e.g. by heat-treatment) to provide crosslinking between the phosphorylated microfibrillated cellulose. Films and hygiene products comprising such films are also described.

It is an object of the present invention to provide a composite sheet, which achieves all of water repellency, water resistance, transparency and mechanical strength. The present invention relates to a sheet having a fiber layer and a coating layer on the fiber layer, wherein the fiber layer comprises ultrafine cellulose fibers having a fiber width of 1000 nm or less in an amount of 60% by mass or more, the haze of the sheet is 20% or less, and the water contact angle of the surface of the sheet on the side of the coating layer which is measured 30 seconds after completion of the dropping of distilled water is 70 degrees or more.

A dynamic cross-linked polymer nanocomposite adhesive has been developed by the oxidation of a thiol functionalized semi-crystalline and/or amorphous oligomer and thiol functionalized Cellulose Nanocrystals (CNCs) to form a polydisulfide network. The resulting solid material has a melting point transition at ca. 75 C. which corresponds to the melting of the semi-crystalline and/or amorphous phase of the nanocomposite adhesive. At higher temperatures (ca. 150 C.), results in the dynamic behavior of the disulfide bond being induced, where the bonds break and reform. Two levels of adhesion are obtained, in some embodiment by (1) heating the adhesive material to 80 C. (melting the semi-crystalline and/or amorphous phase) resulting in a lower modulus/viscosity of the adhesive, thus allowing better surface wetting on a substrate and (2) heating the adhesive material to 150 C. (inducing dynamic behavior of disulfide bonds), further lowers the modulus/viscosity of the adhesive ensuring a much better surface wetting and stronger adhesive bond. The polymer adhesive has been demonstrated to bind to, relatively high surface energy substrates including metal and hydrophilic glass, and to low surface energy substrates such as hydrophobic glass.

The object is to provide a subterranean formation processing composition which has a highly stable viscosity against change in temperature and a high water stopping property. A subterranean formation processing composition comprising cellulose fibers wherein the composition contains ultrafine cellulose fibers having 0.14 to 2.5 mmol/g of a substituent is used. The substituent is preferably an anion group, particularly a phosphoric acid group. The present invention relates to various fluids which are used in well processing. The present invention relates to a method for processing a subterranean formation, for example, drilling of an exploratory well or a wildcat, an appraisal well, an exploratory well or an exploration well, a delineation well, a development well, a production well, an injection well, an observation well, and a service well; cementing; fracturing; and a method for producing petroleum resources. The present invention provides also a cellulose fiber-containing composition which is not limited to the subterranean formation processing use.

The object is to provide a subterranean formation processing composition which has a highly stable viscosity against change in temperature and a high water stopping property. A subterranean formation processing composition comprising cellulose fibers wherein the composition contains ultrafine cellulose fibers having 0.14 to 2.5 mmol/g of a substituent is used. The substituent is preferably an anion group, particularly a phosphoric acid group. The present invention relates to various fluids which are used in well processing. The present invention relates to a method for processing a subterranean formation, for example, drilling of an exploratory well or a wildcat, an appraisal well, an exploratory well or an exploration well, a delineation well, a development well, a production well, an injection well, an observation well, and a service well; cementing; fracturing; and a method for producing petroleum resources. The present invention provides also a cellulose fiber-containing composition which is not limited to the subterranean formation processing use.

It is an object of the present invention to provide a method for producing ultrafine fibrous cellulose, which is capable of efficiently obtaining ultrafine fibrous cellulose having phosphoric acid groups with a high yield. The present invention relates to a method for producing fibrous cellulose having a fiber width of 1000 nm or less, comprising: a (A) of introducing phosphoric acid groups into cellulose fibers to form crosslinked structures via the phosphoric acid groups, thereby obtaining crosslinked phosphorylated cellulose fibers, a (B) of breaking some or all of the crosslinked structures to obtain crosslink-broken phosphorylated cellulose fibers, and a (C) of performing a mechanical treatment on the crosslink-broken phosphorylated cellulose fibers to obtain fibrous cellulose having a fiber width of 1000 nm or less, wherein, in the (A), crosslinked structures in an amount of 0.05 mmol/g or more and 2.0 mmol/g or less are formed, and the (B) is a step of performing the hydrolysis of the crosslinked structures in an aqueous solvent with pH 3 or more.

It is an object of the present invention to provide a method for producing ultrafine fibrous cellulose, which is capable of efficiently obtaining ultrafine fibrous cellulose having phosphoric acid groups with a high yield. The present invention relates to a method for producing fibrous cellulose having a fiber width of 1000 nm or less, comprising: a (A) of introducing phosphoric acid groups into cellulose fibers to form crosslinked structures via the phosphoric acid groups, thereby obtaining crosslinked phosphorylated cellulose fibers, a (B) of breaking some or all of the crosslinked structures to obtain crosslink-broken phosphorylated cellulose fibers, and a (C) of performing a mechanical treatment on the crosslink-broken phosphorylated cellulose fibers to obtain fibrous cellulose having a fiber width of 1000 nm or less, wherein, in the (A), crosslinked structures in an amount of 0.05 mmol/g or more and 2.0 mmol/g or less are formed, and the (B) is a step of performing the hydrolysis of the crosslinked structures in an aqueous solvent with pH 3 or more.

An object of the invention is to provide a material or composition comprising ultrafine cellulose fibers having excellent fluidity. The invention relates to a composition comprising a particulate material comprising ultrafine cellulose fibers and water, and (B) a non-cellulose particulate material in which the water content of the composition is 2 to 94% by mass with respect to the total mass of the composition, and the content of (B) the non-cellulose particulate material is 0.1 to 12% by mass with respect to the total mass of the composition. The invention also relates to a method for producing the composition and a method for producing a material comprising ultrafine cellulose fibers.

An object of the invention is to provide a material or composition comprising ultrafine cellulose fibers having excellent fluidity. The invention relates to a composition comprising a particulate material comprising ultrafine cellulose fibers and water, and (B) a non-cellulose particulate material in which the water content of the composition is 2 to 94% by mass with respect to the total mass of the composition, and the content of (B) the non-cellulose particulate material is 0.1 to 12% by mass with respect to the total mass of the composition. The invention also relates to a method for producing the composition and a method for producing a material comprising ultrafine cellulose fibers.