Filter media comprising non-woven fiber webs and having one or more advantageous structural properties are generally described. In some embodiments, a filter media and/or non-woven fiber web described herein has one or more properties that are both beneficial and easily obtainable by undulating the non-woven fiber web, such as by performing a creping procedure. This property may be characteristic of the procedure employed to form the undulations (e.g., creping and/or microcreping), or may be attainable via one or more methods of undulation.

Filter media comprising non-woven fiber webs and having one or more advantageous structural properties are generally described. In some embodiments, a filter media and/or non-woven fiber web described herein has one or more properties that are both beneficial and easily obtainable by undulating the non-woven fiber web, such as by performing a creping procedure. This property may be characteristic of the procedure employed to form the undulations (e.g., creping and/or microcreping), or may be attainable via one or more methods of undulation.

A composite filament artificial leather includes a composite filament textile and an elastomer film. The composite filament textile includes a plurality of composite filaments. One of the composite filaments includes at least one core portion, a sheath portion and at least one gap structure. The sheath portion is disposed around the core portion. The gap structure is between the core portion and the sheath portion. The elastomer film is bonded with the composite filament textile.

Provided are an air filter medium and an air filter product that can have a long life. The air filter medium includes a filter medium layer that includes first fibers having an average fiber diameter of not less than 5 μm and not greater than 50 μm and second fibers disposed in gaps between the first fibers and having an average fiber diameter of not less than 30 nm and not greater than 1 μm.

Provided are an air filter medium and an air filter product that can have a long life. The air filter medium includes a filter medium layer that includes first fibers having an average fiber diameter of not less than 5 μm and not greater than 50 μm and second fibers disposed in gaps between the first fibers and having an average fiber diameter of not less than 30 nm and not greater than 1 μm.

Provided is a fiber structure which can have both a high filtering efficiency and a small pressure loss. The fiber structure comprises ultrafine fibers having a number average single fiber diameter of 4.5 μm or smaller and non-ultrafine fibers having a number average single fiber diameter of 5.5 μm or larger, wherein the ultrafine fibers and the non-ultrafine fibers are unitedly intermingled, and the fiber structure includes projections on at least one surface thereof. For example, in the fiber structure, the ultrafine fibers may be heat-resistant ultrafine fibers, and the non-ultrafine fibers may be heat-resistant non-ultrafine fibers.

A structure of aligned (e.g., radially and/or polygonally aligned) fibers, and systems and methods for producing and using the same. One or more structures provided may be created using an apparatus that includes one or more first electrodes that define an area and/or partially circumscribe an area. For example, a single first electrode may enclose the area, or a plurality of first electrode(s) may be positioned on at least a portion of the perimeter of the area. A second electrode is positioned within the area. Electrodes with rounded (e.g., convex) surfaces may be arranged in an array, and a fibrous structure created using such electrodes may include an array of wells at positions corresponding to the positions of the electrodes.

A structure of aligned (e.g., radially and/or polygonally aligned) fibers, and systems and methods for producing and using the same. One or more structures provided may be created using an apparatus that includes one or more first electrodes that define an area and/or partially circumscribe an area. For example, a single first electrode may enclose the area, or a plurality of first electrode(s) may be positioned on at least a portion of the perimeter of the area. A second electrode is positioned within the area. Electrodes with rounded (e.g., convex) surfaces may be arranged in an array, and a fibrous structure created using such electrodes may include an array of wells at positions corresponding to the positions of the electrodes.

The network structure has a three-dimensional random loop bonded structure composed of a thermoplastic elastomer continuous linear body having a fiber diameter of not less than 0.1 mm and not more than 3.0 mm, wherein the thermoplastic elastomer continuous linear body is complexed with a polyester-based thermoplastic elastomer and a polystyrene-based thermoplastic elastomer, and the network structure has a 70° C. compressive residual strain of not more than 35% and a rebound resilience of not more than 10%. Thereby, a network structure having a high vibration absorption property and being superior in thermal settling resistance is provided.

A long-fiber nonwoven fabric includes fibers having a birefringence (Δn) of more than or equal to 0.005 and less than or equal to 0.020 and an average fiber diameter of more than or equal to 30 μm and less than or equal to 60 μm, and has a basis weight amount of more than or equal to 50 g/m.sup.2 and less than or equal to 120 g/m.sup.2, an average value of Gurley bending resistances in an MD direction and a CD direction according to JIS L1096 (2010) 8.22.1 Method A of more than or equal to 100 mg and less than or equal to 200 mg, and a value of the Gurley bending resistance in the MD direction/the Gurley bending resistance in the CD direction of less than or equal to 3.0.