Teijin Limited

Akihiro Ohba

Tsutomu Nakamura

Jiro Sadanobu

Takashi Yoshitomi

Kotaro Takiue

Hirozumi Iwasaki

Koki Sasaki

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 filaments are immersed in water to remove the salt and the solvent from the filaments; and (7) the water-washed filaments are drawn and heat-treated.

Process for producing meta-aromatic polyamide fiber

Easily dyeable meta-linkage-containing aromatic polyamide fibers consisting of a composition which comprises a meta-linkage-containing aromatic polyamide incorporating a quaternary onium salt of an alkylbenzenesulfonic acid. They are easily dyeable with cationic dyes, and thus may be used in the fields of bedding, clothing and interior decoration.

Easily dyeable meta-linkage-containing aromatic polyamide fibers

A process is provided for the preparation of a pitch-based carbon fiber having a microstructure consisting of strip-like structural units extended in the longitudinal direction of the fiber, wherein the fractal dimension D of the arrangement of the strip-like structural units in the cross-section of the fiber has a fractal structure satisfying the requirement of the following formula (2) relatively to the observation scale r satisfying the requirement of the following formula (1) with respect to the cross-section of the fiber:

Process for the preparation of pitch-based carbon fiber

A pitch-based carbon fiber having a microstructure consisting of strip-like structural units extended in the longitudinal direction of the fiber, wherein the fractal dimension D of the arrangement of the strip-like structural units in the cross-section of the fiber has a fractal structure satisfying the requirement of the following formula (2) relatively to the observation scale r satisfying the requirement of the following formula (1) with respect to the cross-section of the fiber:

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Iwakuni, Japan

Akihiro Ohba