It is an object of the present invention to provide a resin composite comprising ultrafine cellulose fibers, in which deterioration of a resin component is suppressed. The present invention relates to a cellulose fiber-containing resin composition comprising cellulose fibers with a fiber width of 1000 nm or less having phosphoric acid groups or phosphoric acid group-derived substituents, and a resin, wherein the counterions of the phosphoric acid groups or phosphoric acid group-derived substituents are organic onium ions, and the conjugate bases of the organic onium ions have a pKb value of 1.0 or more.

It is an object of the present invention to provide a thickener capable of exhibiting excellent light resistance. The present invention relates to a thickener comprising cellulose fibers having a fiber width of 8 nm or less and water, wherein the thickener is a slurry or a gel, and when the thickener is filled in a colorless and transparent glass cell having an inside dimension of 1 cm in depth×4 cm in width×4.5 cm in height and the thickener is then irradiated with ultraviolet rays with a wavelength of 300 nm or more and 400 nm or less, using a xenon lamp, from the side of the maximum area surface of the glass cell, so as to be an irradiance of 180 W/m.sup.2 and an integrated light amount of 500 mJ/m.sup.2, the amount of a change in the yellowness before and after ultraviolet irradiation measured in accordance with JIS K 7373 is 10 or less.

A nanocellulose dispersion liquid including nanocellulose and a protic polar solvent having a dielectric constant of not less than 15 and less than 80 at 25° C. The nanocellulose contains a sulfuric acid group and/or a sulfo group derived from a sulfuric acid treatment and an anionic functional group derived from a hydrophilization treatment. Further, the total amount of the sulfuric acid group and/or the sulfo group and the anionic functional group is 0.20 to 4 mmol/g. Also disclosed is a method for producing the nanocellulose dispersion liquid.

The present invention provides resin beads that can provide various types of products, such as a cosmetic having excellent tactile impression, spreadability on the skin, and transparency, that can be substituted for resin particles composed of a synthetic material derived from petroleum, and that have favorable biodegradability, and the present invention also provides various types of products, such as a cosmetic using the resin beads. The resin beads are formed with a resin containing cellulose as a main component. The resin beads have a cumulative 50% particle size on a volume basis of 50 μm or smaller, a degree of sphericity of 0.7 to 1.0, a degree of surface smoothness of 70 to 100%, a degree of solidity of 50 to 100%, and a biodegradation rate for 5 days, as measured in accordance with JIS K6950:2000 (ISO 14851:1999), of 20% or more, and the content of the cellulose in the resin is 90 to 100% by mass. In addition, the present invention provides a product of any one of a cosmetic, a dermatological preparation, a paint, a shaped article, a film, a coating agent, and a resin composition which contain the resin beads.

An object of the invention is to provide a material comprising ultrafine cellulose fibers, having good dispersibility of fine particles in an aqueous medium containing ultrafine cellulose fibers. According to the invention, there is provided a material comprising ultrafine cellulose fibers, wherein the content of the ultrafine cellulose fibers is 80% by mass or more, and the haze value of a sample, which has been prepared by adding the material comprising ultrafine cellulose fibers to pure water to a solid concentration of 0.4% by mass, and stirring the mixture with a disperser under conditions of 1500 rpm and 5 minutes, is 20% or less.

An object of the present invention is to improve the strength of a sheet containing substituent-introduced ultrafine fiber under high-humidity conditions while maintaining its high transparency. The sheet of the present invention comprises ultrafine fiber having an ionic substituent, and a divalent or higher metal, and has a haze of 10.0% or less.

It is an object of the present invention to provide a resin composite comprising ultrafine cellulose fibers, in which deterioration of a resin component is suppressed. The present invention relates to a cellulose fiber-containing resin composition comprising cellulose fibers with a fiber width of 1000 nm or less having phosphoric acid groups or phosphoric acid group-derived substituents, and a resin, wherein the counterions of the phosphoric acid groups or phosphoric acid group-derived substituents are organic onium ions, and the conjugate bases of the organic onium ions have a pKb value of 1.0 or more.

It is an object of the present invention to provide a thickener capable of exhibiting excellent light resistance. The present invention relates to a thickener comprising cellulose fibers having a fiber width of 8 nm or less and water, wherein the thickener is a slurry or a gel, and when the thickener is filled in a colorless and transparent glass cell having an inside dimension of 1 cm in depth4 cm in width4.5 cm in height and the thickener is then irradiated with ultraviolet rays with a wavelength of 300 nm or more and 400 nm or less, using a xenon lamp, from the side of the maximum area surface of the glass cell, so as to be an irradiance of 180 W/m.sup.2 and an integrated light amount of 500 mJ/m.sup.2, the amount of a change in the yellowness before and after ultraviolet irradiation measured in accordance with JIS K 7373 is 10 or less.

The present invention provides resin beads that can provide various types of products, such as a cosmetic having excellent tactile impression, spreadability on the skin, and transparency, that can be substituted for resin particles composed of a synthetic material derived from petroleum, and that have favorable biodegradability, and the present invention also provides various types of products, such as a cosmetic using the resin beads. The resin beads are formed with a resin containing cellulose as a main component. The resin beads have a cumulative 50% particle size on a volume basis of 50 m or smaller, a degree of sphericity of 0.7 to 1.0, a degree of surface smoothness of 70 to 100%, a degree of solidity of 50 to 100%, and a biodegradation rate for 5 days, as measured in accordance with JIS K6950:2000 (ISO 14851:1999), of 20% or more, and the content of the cellulose in the resin is 90 to 100% by mass. In addition, the present invention provides a product of any one of a cosmetic, a dermatological preparation, a paint, a shaped article, a film, a coating agent, and a resin composition which contain the resin beads.

A dispersion of a cellulose nanofiber (CNF) and a cellulose nanocrystal (CNC) that maintains a physical property even after drying and redispersing and has a long pot life is provided. A composite of the CNF and the CNC having a higher rupture strength and a higher oxygen gas barrier property is also provided. The dispersion contains a CNF having a sulfate ester group and a CNC having a sulfate ester group. The composite contains the CNF having a sulfate ester group and the CNC having a sulfate ester group.