Provided are: a high-melting-point resin fiber having heat resistance and solvent resistance, offering excellent workability/formability, and having a diameter of 4 μm or less; and a nonwoven fabric including the high-melting-point resin fiber. Also provided is a method for efficiently producing a high-melting-point resin fiber having a diameter of 4 μm or less, via laser melt electrospinning. The high-melting-point resin fiber according to the present invention includes a resin having a melting point of 250° C. or higher and has a diameter of 4 μm or less. In the high-melting-point resin fiber, the resin having a melting point of 250° C. or higher is preferably a PEEK. The fiber preferably has a degree of crystallinity of 30% or less.

A method for producing a fiber preform or semi-finished textile product comprises providing a fiber preform or semi-finished textile product comprising at least one thermoplastic fiber. The thermoplastic fiber has a core constructed of a first material, a shell constructed of a second material positioned to surround the core, and magnetic particles that are one of mainly arranged in the shell, almost exclusively arranged in the shell, and exclusively arranged in the shell. Continually adding the fiber preform or semi-finished textile product with simultaneous heating thereof in continuous passing through or passing by a magnetic induction heating device or the same by way of a relative movement. Fixing the fiber preform or semi-finished textile product by allowing the fiber preform or semi-finished textile product to rigidify.

Provided are an amorphous polyetherimide fiber having not only a small single fiber fineness suitable for producing fabrics, and a fabric comprising the amorphous polyetherimide fiber. The fiber comprises an amorphous polyetherimide polymer having a molecular weight distribution (Mw/Mn) of less than 2.5, and having a shrinkage percentage under dry heat at 200° C. of 5% or less, and a single fiber fineness of 3.0 dtex or less. The fiber may have a tenacity at room temperature of 2.0 cN/dtex or greater.

Provided are an amorphous polyetherimide fiber having not only a small single fiber fineness suitable for producing fabrics, and a fabric comprising the amorphous polyetherimide fiber. The fiber comprises an amorphous polyetherimide polymer having a molecular weight distribution (Mw/Mn) of less than 2.5, and having a shrinkage percentage under dry heat at 200° C. of 5% or less, and a single fiber fineness of 3.0 dtex or less. The fiber may have a tenacity at room temperature of 2.0 cN/dtex or greater.

Fibers, prepreg materials, compositions, composite articles, and methods of producing composite articles are disclosed herein. A fiber may include at least one polymeric fiber and a plurality of carbon nanotubes. The at least one polymeric fiber extends in a lengthwise direction. The at least one polymeric fiber is a nanofiber.

Polyacetal fibers having excellent spinning stability and uniform appearance and production methods thereof have been awaited. According to the invention, a polyacetal fiber, comprising 0.05 to 1.3 parts by mass of an inorganic filler with respect to 100 parts by mass of a polyacetal resin, in which the inorganic filler has a primary average particle size of more than 0.5 μm and 10 μm or less, and the polyacetal fiber has a melt flow index of 15 to 45 g/10 min, is provided.

Provided are a continuous-fiber nonwoven fabric having excellent denseness, a composite material including the nonwoven fabric and having good appearance, and a method for producing the composite material. The continuous-fiber nonwoven fabric includes fibers containing an amorphous thermoplastic phenoxy resin as a main component, wherein the thermoplastic phenoxy resin has a weight-average molecular weight in a range of from 10,000 to 100,000 and a glass transition temperature equal to or lower than 100° C. For example, the continuous-fiber nonwoven fabric may be a melt-blown nonwoven fabric or a spunbonded nonwoven fabric.

A composite electrode includes two or more types of fibers forming a fiber network, comprising at least a first type of fibers and a second type of fibers. The first type of fibers comprises a first polymer and a first type of particles. The second type of fibers comprises a second polymer and a second type of particles. The second polymer is same as or different from the first polymer. The second type of particles are same as or different from the first type of particles.

A polymer includes a repeating unit M and a repeating unit D, the repeating unit M is —COC.sub.6H.sub.6CONHCH.sub.2CH.sub.2O—, the repeating unit D is —COC.sub.6H.sub.6COOCH.sub.2CH.sub.2O—, and a molar ratio of the repeating unit M to the repeating unit D is 1:6 to 1:999.

A polymer includes a repeating unit M and a repeating unit D, the repeating unit M is —COC.sub.6H.sub.6CONHCH.sub.2CH.sub.2O—, the repeating unit D is —COC.sub.6H.sub.6COOCH.sub.2CH.sub.2O—, and a molar ratio of the repeating unit M to the repeating unit D is 1:6 to 1:999.