Abstract: By forming a meta-type wholly aromatic polyamide fiber using a highly hydrophobic UV absorber and having specific physical properties, a meta-type wholly aromatic polyamide fiber having light resistance, which can be dyed in various hues by carrier dyeing and in which the shedding of a light stabilizer during dyeing can be suppressed, is provided. That is, the meta-type wholly aromatic polyamide fiber contains a UV absorber with a water solubility of less than 0.04 mg/L and has a degree of dye exhaustion of 90% or more in the form of a dyed fiber and a light resistance retention of 80% or more after carrier dyeing.

Abstract: Upon producing a meta-type wholly aromatic polyamide fiber by wet spinning a polymer solution containing a meta-type wholly aromatic polyamide containing a m-phenylenediamine isophthalamide skeleton as a major component, and an amide solvent containing a salt, (1) the polymer solution is ejected into a coagulation bath containing an amide solvent and water and containing a salt at a low concentration to coagulate as a porous thread body (fibrous material), (2) which is subsequently stretched in a plastic stretching bath containing an aqueous solution of an amide solvent, (3) is rinsed with water and then subjected to a heat treatment in a saturated steam atmosphere, and (4) is then subjected to a dry heat treatment, so as to produce a novel meta-type wholly aromatic polyamide fiber that contains an extremely small amount of a solvent remaining in the fibers, contains a small amount of a volatile substance harmful in a heat treatment step at a high temperature, is capable of suppressing coloration of a fiber p

Abstract: By forming a meta-type wholly aromatic polyamide fiber using a highly hydrophobic UV absorber and having specific physical properties, a meta-type wholly aromatic polyamide fiber having light resistance, which can be dyed in various hues by carrier dyeing and in which the shedding of a light stabilizer during dyeing can be suppressed, is provided. That is, the meta-type wholly aromatic polyamide fiber contains a UV absorber with a water solubility of less than 0.04 mg/L and has a degree of dye exhaustion of 90% or more in the form of a dyed fiber and a light resistance retention of 80% or more after carrier dyeing.

Abstract: Wholly aromatic polyamide fibers having non-fusible fine powder attached to a surface thereof in an amount of from 1.5 to 14 mg/m2, which are good in process stability in working processes, and exhibit excellent reinforcing effect upon using as a reinforcing material of rubber, resins and the like.

Abstract: Upon producing a meta-type wholly aromatic polyamide fiber by wet spinning a polymer solution containing a meta-type wholly aromatic polyamide containing a m-phenylenediamine isophthalamide skeleton as a major component, and an amide solvent containing a salt, (1) the polymer solution is ejected into a coagulation bath containing an amide solvent and water and containing a salt at a low concentration to coagulate as a porous thread body (fibrous material), (2) which is subsequently stretched in a plastic stretching bath containing an aqueous solution of an amide solvent, (3) is rinsed with water and then subjected to a heat treatment in a saturated steam atmosphere, and (4) is then subjected to a dry heat treatment, so as to produce a novel meta-type wholly aromatic polyamide fiber that contains an extremely small amount of a solvent remaining in the fibers, contains a small amount of a volatile substance harmful in a heat treatment step at a high temperature, is capable of suppressing coloration of a fiber p

Abstract: A composite yarn having a high reinforcing effect on a matrix material to be reinforced is a paralleled yarn of at least one substantially non-twisted multifilament yarn having a tensile strength of 13 cN/dtex or more and an initial modulus of 300 cN/dtex or more with at least one substantially non-twisted staple fiber yarn having a staple fiber fraction (1) having a fiber length of 1.5 times or more the average fiber length of the staple fibers and another fraction (2) having a fiber length of 0.5 time or less the average fiber length, in which a portion of the staple fibers in the staple fiber yarn winds around the periphery of the paralleled composite yarn to thereby bind the multifilament yarn and the staple fiber yarn substantially into a composite yarn without twisting the composite yarn.

Abstract: A spanized yarn constituted by a high strength short fiber containing at least one polymer selected from the group consisting of poly-p-phenylene terephthalamide, poly-p-phenylene benzoxazole, polyethylene, polyvinyl alcohol and wholly aromatic polyester and having a strength of 14 cN/dtex or more, and the high strength short fiber has an average single yarn length of from 50 to 90 cm and a coefficient of variation (CV) in average single yarn length of 50% or less.

Abstract: Wholly aromatic polyamide fibers having non-fusible fine powder attached to a surface thereof in an amount of from 1.5 to 14 mg/m2, which are good in process stability in working processes, and exhibit excellent reinforcing effect upon using as a reinforcing material of rubber, resins and the like.

Abstract: A composite yarn having a high reinforcing effect on a matrix material to be reinforced is a paralleled yarn of at least one substantially non-twisted multifilament yarn having a tensile strength of 13 cN/dtex or more and an initial modulus of 300 cN/dtex or more with at least one substantially non-twisted staple fiber yarn having a staple fiber fraction (1) having a fiber length of 1.5 times or more the average fiber length of the staple fibers and another fraction (2) having a fiber length of 0.5 time or less the average fiber length, in which a portion of the staple fibers in the staple fiber yarn winds around the periphery of the paralleled composite yarn to thereby bind the multifilament yarn and the staple fiber yarn substantially into a composite yarn without twisting the composite yarn.

Abstract: To produce meta aramid filaments having a good quality from a polymer solution of a meta aramid produced by a solution polymerization method, with high efficiency, (1) a meta aramid is prepared by polymerization-reacting a aromatic meta-diamine with a aromatic meta-dicarboxylic acid chloride in a polar organic solvent; (2) hydrogen chloride contained in the resultant polymer solution is neutralized with a neutralizing agent containing an alkali metal hydroxide which can react with hydrogen chloride to produce a salt thereof insoluble in the polymerization solvent; (3) the salt deposited from the polymer solution is removed by filtration; (4) the resultant polymer solution is mixed with water and a polar organic amide solvent to prepare a spinning solution; (5) the resultant meta aramid spinning solution is directly extruded in the form of filamentary streams into an aqueous coagulation liquid, to coagulate the extruded filamentary streams of the polymer solution into the form of filaments; (6) the coagulated