Abstract: There is disclosed an acrylic fiber (a) consisting of an acrylonitrile polymer comprising an acrylonitrile unit in at least 80 wt % and less than 95 wt %, (b) having a monofilament dry strength of 2.5 to 4.0 cN/dtex, (c) having a monofilament dry elongation of 35 to 50 %, and (d) forming a crack with a length of 20 &mgr;m or more in its tension rupture lateral surface along the filament axis direction when rupturing the monofilament in a tension test. The fiber has even orientation in its surface and inside; is significantly improved in dry strength, dry elongation and dyeability; and exhibits wool-like hand feeling. It is, therefore, quite suitable as a synthetic fiber for various applications such as a garment material, e.g., a sweater and a home furnishing material such as a pile.

Abstract: There is disclosed an acrylic fiber (a) consisting of an acrylonitrile polymer comprising an acrylonitrile unit in at least 80 wt % and less than 95 wt %, (b) having a monofilament dry strength of 2.5 to 4.0 cN/dtex, (c) having a monofilament dry elongation of 35 to 50%, and (d) forming a crack with a length of 20 &mgr;m or more in its tension rupture lateral surface along the filament axis direction when rupturing the monofilament in a tension test. The fiber has even orientation in its surface and inside; is significantly improved in dry strength, dry elongation and dyeability; and exhibits wool-like hand feeling. It is, therefore, quite suitable as a synthetic fiber for various applications such as a garment material, e.g., a sweater and a home furnishing material such as a pile.

Abstract: There is disclosed an acrylic fiber (a) consisting of an acrylonitrile polymer comprising an acrylonitrile unit in at least 80 wt % and less than 95 wt %, (b) having a monofilament dry strength of 2.5 to 4.0 cN/dtex, (c) having a monofilament dry elongation of 35 to 50%, and (d) forming a crack with a length of 20 &mgr;m or more in its tension rupture lateral surface along the filament axis direction when rupturing the monofilament in a tension test. The fiber has even orientation in its surface and inside; is significantly improved in dry strength, dry elongation and dyeability; and exhibits wool-like hand feeling. It is, therefore, quite suitable as a synthetic fiber for various applications such as a garment material, e.g., a sweater and a home furnishing material such as a pile.

Abstract: There is disclosed an acrylic fiber (a) consisting of an acrylonitrile polymer comprising an acrylonitrile unit in at least 80 wt % and less than 95 wt %, (b) having a monofilament dry strength of 2.5 to 4.0 cN/dtex, (c) having a monofilament dry elongation of 35 to 50%, and (d) forming a crack with a length of 20 &mgr;m or more in its tension rupture lateral surface along the filament axis direction when rupturing the monofilament in a tension test. The fiber has even orientation in its surface and inside; is significantly improved in dry strength, dry elongation and dyeability; and exhibits wool-like hand feeling. It is, therefore, quite suitable as a synthetic fiber for various applications such as a garment material, e.g., a sweater and a home furnishing material such as a pile.

Abstract: There is disclosed an acrylonitrile fiber bundle for a carbon fiber precursor with a total denier of 30,000 or more consisting of an acrylonitrile polymer comprising 95 wt % or more of an acrylonitrile unit, wherein the surface of filaments composing of the fiber bundle has 2 to 15 corrugation with a height of 0.5 to 1.0 &mgr;m which are substantially continuous in a longitudinal direction and an iodine adsorption per a fiber weight of the fiber bundle is 0.5 to 1.5 wt %. The fiber bundle shows a large total size, a small drying load owing to its good denseness and a good convergence so that it is suitably used as precursors for carbon fibers.

Abstract: There is disclosed an acrylic fiber (a) consisting of an acrylonitrile polymer comprising an acrylonitrile unit in at least 80 wt % and less than 95 wt %, (b) having a monofilament dry strength of 2.5 to 4.0 cN/dtex, (c) having a monofilament dry elongation of 35 to 50%, and (d) forming a crack with a length of 20 &mgr;m or more in its tension rupture lateral surface along the filament axis direction when rupturing the monofilament in a tension test. The fiber has even orientation in its surface and inside; is significantly improved in dry strength, dry elongation and dyeability; and exhibits wool-like hand feeling. It is, therefore, quite suitable as a synthetic fiber for various applications such as a garment material, e.g., a sweater and a home furnishing material such as a pile.

Abstract: There are disclosed a method of purifying a polyacrylonitrile which comprises removing iron compounds or ions thereof and aluminum compounds or ions thereof which can be contained as impurities in a polyacrylonitrile obtained by aqueous suspension polymerization using an inorganic redox initiator, from a solution consisting of said polyacrylonitrile and an organic solvent capable of dissolving said polyacrylonitrile, by the use of a substance having ion-exchanging ability which is insoluble in said organic solvent; a process for producing fiber from the polyacrylonitrile thus purified; and a process for producing carbon fiber from said fiber.