An acrylic fiber is composed of an acrylic polymer. The acrylic polymer includes acrylonitrile, wherein the acrylic fiber has a deformation degree of 0.13 or less and a surface roughness of 6000 m.sup.2 or less. A method for producing an acrylic fiber by wet spinning or dry-wet spinning includes: dissolving an acrylic polymer in an organic solvent to form a spinning solution, the acrylic polymer including acrylonitrile; discharging the spinning solution into a coagulation bath to form an acrylic fiber; water washing the acrylic fiber; and drying the acrylic fiber, wherein, before drying the acrylic fiber, the acrylic fiber is pressed with a nip roll and subjected to pre-drying using a dryer into which steam is fed.

An acrylic fiber is composed of an acrylic polymer. The acrylic polymer includes acrylonitrile, wherein the acrylic fiber has a deformation degree of 0.13 or less and a surface roughness of 6000 m.sup.2 or less. A method for producing an acrylic fiber by wet spinning or dry-wet spinning includes: dissolving an acrylic polymer in an organic solvent to form a spinning solution, the acrylic polymer including acrylonitrile; discharging the spinning solution into a coagulation bath to form an acrylic fiber; water washing the acrylic fiber; and drying the acrylic fiber, wherein, before drying the acrylic fiber, the acrylic fiber is pressed with a nip roll and subjected to pre-drying using a dryer into which steam is fed.

An acrylic fiber for artificial hair includes an acrylic polymer, wherein the acrylic polymer includes 29.5 to 79.5% by mass of acrylonitrile, 20 to 70% by mass of vinyl chloride and/or vinylidene chloride, and 0.5 to 5% by mass of a vinyl monomer comprising a sulfonic acid group. The acrylic fiber for artificial hair includes 0.3 to 2% by mass of a good solvent for the acrylic polymer and 0.1 to 5% by mass of a compound comprising an epoxy group.

An acrylic fiber for artificial hair includes an acrylic polymer, wherein the acrylic polymer includes 29.5 to 79.5% by mass of acrylonitrile, 20 to 70% by mass of vinyl chloride and/or vinylidene chloride, and 0.5 to 5% by mass of a vinyl monomer comprising a sulfonic acid group. The acrylic fiber for artificial hair includes 0.3 to 2% by mass of a good solvent for the acrylic polymer and 0.1 to 5% by mass of a compound comprising an epoxy group.

A flame-retardant modacrylic fiber including a modacrylic copolymer in an amount of 100 parts by mass, and a zinc stannate compound in an amount of 1 to 18 parts by mass, wherein the zinc stannate compound has an average particle size D50 of 0.5 ?m or more is provided. Further, a flame-retardant fiber composite and a flame-retardant work clothing including the flame-retardant modacrylic fiber in an amount of 30 to 80 mass %, and one or more other fibers selected from the group consisting of natural fibers and chemical fibers in an amount of 20 to 70 mass % are provided.

A flame-retardant modacrylic fiber including a modacrylic copolymer in an amount of 100 parts by mass, and a zinc stannate compound in an amount of 1 to 18 parts by mass, wherein the zinc stannate compound has an average particle size D50 of 0.5 ?m or more is provided. Further, a flame-retardant fiber composite and a flame-retardant work clothing including the flame-retardant modacrylic fiber in an amount of 30 to 80 mass %, and one or more other fibers selected from the group consisting of natural fibers and chemical fibers in an amount of 20 to 70 mass % are provided.

A flame-retardant fiber composite includes an acrylic fiber A containing an acrylic copolymer and an aramid fiber. The acrylic fiber A is substantially free of an antimony compound, and the flame-retardant fiber composite forms a surface-foamed char layer when burned. A flame-retardant work clothing includes the flame-retardant acrylic fiber. A highly flame-retardant fiber composite and highly flame-retardant work clothing include an acrylic fiber, and are capable of exhibiting high flame retardancy while suppressing environmental impacts caused by a flame retardant.

Artificial hair includes a fiber bundle including a large crimp part having alternatively formed first peak parts and first valley parts with a minimum pitch of 1 mm or more. A minimum amplitude of the large crimp part is 0.30 mm or more and 4 mm or less, and the large crimp part includes a small crimp part having a pitch smaller than that of the large crimp part near one peak part. The small crimp part has alternatively formed second peak parts and second valley parts, and wherein a minimum amplitude of the small crimp part is smaller than the minimum amplitude of the large crimp part.

Artificial hair includes a fiber bundle including a large crimp part having alternatively formed first peak parts and first valley parts with a minimum pitch of 1 mm or more. A minimum amplitude of the large crimp part is 0.30 mm or more and 4 mm or less, and the large crimp part includes a small crimp part having a pitch smaller than that of the large crimp part near one peak part. The small crimp part has alternatively formed second peak parts and second valley parts, and wherein a minimum amplitude of the small crimp part is smaller than the minimum amplitude of the large crimp part.

A one-fabric fire resistant (FR) solution having 2 or more layers of FR yarns knit together into one fabric, the at 2 or more layers including a face layer and a back layer, the back layer includes a silica yarn.