Yarns are formed of a copolyamide in an amount of at least 90 wt % with respect to the total weight of the yarn, wherein copolyamide includes (a) at least 95 wt % by weight with respect to the total weight of copolyamide, monomeric units derived from hexamethylene diamine and adipic acid and (b1) cyclic monomeric units derived from a diamine X, and cyclic monomeric units derived from a diacid Y, and/or b2) cyclic monomeric units derived from an amino acid Z. The summed amount of monomeric units derived from X, Y and Z is between 0.1 to 4.5 wt % by weight with respect to the total weight of the copolyamide. The yarns have a tensile strength of at least 80 cN/tex as measured according to ASTM D885-04.

The present invention concerns fiber made from a polymer comprising imidazole groups, fiber further having: i) a halide anion, the halide anion being present in an amount of 0.05 to 20.1 weight percent, based on weight of fiber; and ii) sulfur, wherein the sulfur is present in the fiber in an amount of 0.05 to 3 weight percent; the fiber exhibiting hydrochloric acid evolution as identified by TGA-IR between 277.13 C. to 448.19 C.

The present invention concerns fiber made from a polymer comprising imidazole groups, the polymer further having: i) halide anions being present in an amount in the range of 0.05 to 20.1 weight percent, based on weight of fiber; ii) sulfur, wherein the sulfur is present in the fiber in an amount in the range of 0.05 to 3 weight percent, based on weight of fiber; and iii) alkali metal ion, wherein the alkali metal ion is present in the fiber in an amount in the range of 0.05 to 2 weight percent, based on weight of fiber, the fiber exhibiting hydrochloric acid evolution as identified by TGA-IR between 277.13 C. to 448.19 C.

The invention relates to a yarn comprising a copolyamide in an amount of at least 90 wt % with respect to the total weight of the yarn, which copolyamide comprises a) at least 95 wt % by weight with respect to the total weight of copolyamide, monomeric units derived from hexamethylene diamine and adipic acid and b1) cyclic monomeric units derived from a diamine X, and cyclic monomeric units derived from a diacid Y, and/or b2) cyclic monomeric units derived from an amino acid Z, in which the summed amount of monomeric units derived from X,Y and Z is between 0.1 to 4.5 wt % by weight with respect to the total weight of the copolyamide and wherein the yarn has a tensile strength of at least 80 cN/tex as measured according to ASTM D885-04. The invention also relates to a process for preparing the yarn.

A problem of the invention is to provide a colored organic fiber that has a deep color and excellent flame retardancy, a cloth and garments each composed of the foregoing organic fiber, and a method for producing a cloth. To solve this problem, a colored organic fiber having a content of a carrier agent of 1.8% by mass or less relative to the fiber mass is provided. A cloth or garments are obtained, if desired.

The invention concerns fiber, and a process for making same, the fiber comprising a mixture of at least a first polymer and a second polymer, the first polymer having a structure derived from the reaction of one or more amine monomers and a plurality of acid monomers, wherein the one or more amine monomers includes at least 60 mole percent 5(6)-amino-2-(p-aminophenyl)benzimidazole, and the plurality of acid monomers include those having a structure of
ClCOAr.sub.1COCl and ClCOAr.sub.2COCl
wherein Ar.sub.1 is an aromatic group having para-oriented linkages and Ar.sub.2 is an aromatic group having meta-oriented linkages, and wherein the plurality of acid monomers has at least 50 mole percent of the monomer containing aromatic group Ar.sub.2; and the second polymer has a structure derived from the reaction of metaphenylene diamine and isophthaloyl chloride. This fiber has use in heat-resistant protective apparel fabrics and garments.

A filament comprising a polymer blend and specific articles comprising the filament are disclosed. The polymer blend includes an aliphatic nylon and a semiaromatic nylon. The aliphatic nylon is the major component of the blend and semiaromatic nylon is the minor component of the blend. The aliphatic nylon can be Nylon 6, Nylon 66, Nylon 610, Nylon 612, Nylon 12, and mixtures thereof. The semiaromatic nylon can be 6I/6T, 6T/6I, and mixtures thereof. The nylon blend filament provides enhanced mechanical properties such as modulus, ultimate strength, and yield strength with improved processability and reduced diameter variability at a reduced cost.

The present invention concerns methods for removing sulfur from yarn comprising the steps of: a) contacting never-dried polymeric yarn with an aqueous base, the polymer comprising imidazole groups and said polymer comprising sulfur atoms characterized as being in the form of sulfate anions; b) contacting the yarn with an aqueous acid comprising a halide; and c) rinsing the yarn.

Provided is a semi-aromatic polyamide fiber having excellent spinning stability, heat resistance and chemical resistance. The semi-aromatic polyamide fiber includes a semi-aromatic polyamide resin having a melting point of 290? C. or higher and a plasticizer having a 5% thermal weight reduction temperature of 320? C. or higher, the resin having as a dicarboxylic acid component an aromatic dicarboxylic acid unit and as a diamine component 1,9-nonanediamine unit and 2-methyl-1,8-octanediamine unit in a molar ratio (the former:the latter) of 70:30 to 99:1.

A filament comprising a polymer blend and specific articles comprising the filament are disclosed. The polymer blend includes an aliphatic nylon and a semiaromatic nylon. The aliphatic nylon is the major component of the blend and semiaromatic nylon is the minor component of the blend. The aliphatic nylon can be Nylon 6, Nylon 66, Nylon 610, Nylon 612. Nylon 12, and mixtures thereof. The semiaromatic nylon can be 6I/6T, 6T/6I, and mixtures thereof. The nylon blend filament provides enhanced mechanical properties such as modulus, ultimate strength, and yield strength with improved processability and reduced diameter variability at a reduced cost.