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.

A laminated film includes a polylactic acid-based resin layer and one or more acetylated hyaluronic acid layers laminated on a side of the polylactic acid-based resin layer, is highly flexible and easy to handle and, when stuck to an adherend with curved surface, the laminated film has excellent followability, adhesiveness and coating properties to the adherend, since the acetylated hyaluronic acid layer(s) can be removed easily with an aqueous solution from the polylactic acid-based resin layer in a thin film shape. The acetylated hyaluronic acid and the polylactic acid-based resin are biodegradable and, therefore, the laminated film is highly compatible with skin and organs such as visceral organs. The laminated film is optimally usable as a dermal material for external application such as a wound coating material, an adhesion inhibitor and skin care articles.

A laminated film includes a polylactic acid-based resin layer and one or more acetylated hyaluronic acid layers laminated on a side of the polylactic acid-based resin layer, is highly flexible and easy to handle and, when stuck to an adherend with curved surface, the laminated film has excellent followability, adhesiveness and coating properties to the adherend, since the acetylated hyaluronic acid layer(s) can be removed easily with an aqueous solution from the polylactic acid-based resin layer in a thin film shape. The acetylated hyaluronic acid and the polylactic acid-based resin are biodegradable and, therefore, the laminated film is highly compatible with skin and organs such as visceral organs. The laminated film is optimally usable as a dermal material for external application such as a wound coating material, an adhesion inhibitor and skin care articles.

A gas-barrier composition including nanocellulose containing at least one of a sulfuric acid group, a sulfo group, or a phosphoric acid group; and a reactive crosslinking agent.

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 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.

The present invention provides a rubber modifier capable of exhibiting good dispersibility in a dispersion thereof and excellent in a rubber-modifying effect such as rubber-reinforcing effect or the likes. The invention relates to a rubber modifier comprising cellulose fibers, in which the number of the cellulose fibers having a fiber length of 450 nm or less, relative to the number of all the cellulose fibers therein, is 50% or more, to a rubber modifier dispersion comprising the rubber modifier and a dispersion medium, and to a rubber composition comprising the rubber modifier and a rubber component.

The present invention provides a rubber modifier capable of exhibiting good dispersibility in a dispersion thereof and excellent in a rubber-modifying effect such as rubber-reinforcing effect or the likes. The invention relates to a rubber modifier comprising cellulose fibers, in which the number of the cellulose fibers having a fiber length of 450 nm or less, relative to the number of all the cellulose fibers therein, is 50% or more, to a rubber modifier dispersion comprising the rubber modifier and a dispersion medium, and to a rubber composition comprising the rubber modifier and a rubber component.