Coated and expanded, nanofiber structures are provided and methods of use thereof.

Disclosed herein is a method for producing an elastically stretchable artificial leather, which includes the steps of forming microfiberizable fibers into a web, entangling the obtained web to produce an entangled nonwoven fabric, converting the microfiberizable fibers in the nonwoven fabric to microfine fibers thereby producing a substrate for artificial leather, producing an artificial leather from the obtained substrate for artificial leather, bringing the obtained artificial leather into close contact with an elastomer sheet stretched in a machine direction by 5 to 40%, shrinking the artificial leather in the machine direction simultaneously with the elastomer sheet by relaxing elongation of the elastomer sheet to obtain an artificial leather in shrunk state, heat treating the artificial leather in shrunk state, and then peeling the heat treated artificial leather off from the elastomer sheet.

Disclosed is a napped artificial leather including: a fiber-entangled body including ultrafine fibers having a fineness of 0.5 dtex or less; and an elastic polymer impregnated into the fiber-entangled body, the napped artificial leather having a thickness of 0.25 to 1.5 mm, and including a main surface that is a napped surface formed by napping the ultrafine fibers. The napped artificial leather further includes phosphorous-based flame retard ant particles attached to the elastic polymer such as a polyurethane, the phosphorous-based flame retardant particles being locally present in a range of a thickness of 200 pm or less from a back surface opposite to the main surface. The phosphorous-based flame retardant particles have an average particle size of 0.1 to 30 μm, a phosphorus atom content of 14 mass % or more, and a solubility in water at 30° C. of 0.2 mass % or less, and a melting point, or, in the absence of a melting point, a decomposition temperature, of 150° C. or more, and a content ratio of the phosphorous-based flame retardant particles is 1 to 6 mass % as a content ratio in terms of phosphorus atoms.

Disclosed is an artificial leather base material including: a non-woven fabric that is an entangle body of fibers (A) and fibers (B); and an elastic polymer applied inside the non-woven fabric, wherein the fibers (A) are crimped fibers that are formed from two types of resins with intrinsic viscosities different from each other, and that are filaments of 0.6 dtex or more, and the fibers (B) are ultrafine fibers of less than 0.6 dtex.

A composite sheet material includes a skin sheet and a woven fabric, wherein the skin sheet is formed by impregnating an elastic polymer into a base material consisting of an entangled fiber network, such as a nonwoven fabric, and wherein the composite sheet material has high thermal resistance and high formability suitable for integral molding. The composite sheet material is a composite sheet material including a skin sheet attached with a woven fabric through an adhesive resin layer, wherein the skin sheet is made of an entangled fiber network including ultra-fine fibers with an average single fiber diameter of 0.1 to 8 μm and of an elastic polymer, and wherein the woven fabric includes polyester fibers in which the polyester contains a 1,2-propanediol-derived component at a concentration of 1 to 500 ppm.

A method of forming a shoe upper includes obtaining a mold defining a shoe component, spraying a polymer formulation onto the mold to form a sprayed polymer formulation layer, curing the sprayed polymer formulation layer to form a polymer film, removing the film from the mold, and incorporating the film into the shoe upper.

An artificial leather is provided that, due to excellent texture and mechanical strength (abrasion resistance, etc.), can be appropriately used in, for example, clothing products, or sheets of skin material or interior material, etc. for interiors, automobiles, airplanes, rail cars, etc. One embodiment of the present invention is an artificial leather that includes a fiber sheet and a polyurethane resin, wherein the fiber sheet includes a scrim that is a woven or knitted fabric, and a fiber layer (A) that constitutes a first outer surface of the artificial leather, such that in a thickness direction cross-section of the fiber layer (A), the ratio (d/D) of the total area (d) of the polyurethane resin that forms a closed shape having an area of 100 μm2 or more to the total area (D) of the polyurethane resin satisfies the following formula (1): 5≤(d/D)×100≤50 (%).

A sheet material has good mechanical properties, flexibility, lightweight properties, and quality, and also relates to a production method therefor. The sheet material includes, as constitutional components, an elastic polymer and nonwoven fabric composed mainly of ultrafine hollow fiber with an average monofilament diameter in the range of 0.05 to 10 μm, the ultrafine hollow fiber containing 2 to 60 hollows.

Disclosed is a grain-finished artificial leather including: an artificial leather base material; and a resin layer stacked on at least one surface of the artificial leather base material, wherein the artificial leather base material contains: a fiber-entangled body of ultrafine fibers; 3 to 50 mass % of a first elastic polymer; 2.5 to 6 mass %, in terms of phosphorus atoms, of first phosphorous-based flame retardant particles having an average particle size of 1 to 10 μm; and 1 to 6 mass % of a plasticizer, and the resin layer contains: a second elastic polymer; and a total content, in terms of phosphorus atoms or in terms of hydroxyl groups, of 0 to 8 mass % of flame retardant particles having an average particle size of 1 to 10 μm and being at least one selected from the group consisting of second phosphorous-based flame retardant particles and first metal hydroxide particles.

Disclosed is a method for producing a nanofibrous non-woven material and a nanofibrous non-woven material with cross-linked gelatin nanofibers. The method includes producing gelatin nanofibers; producing a nanofibrous material using the produced gelatin nanofibers; and treating the nanofibrous material by a crosslinking agent for forming adhesion bonds in the nanofibrous material and to obtain the nanofibrous non-woven material.