Teijin Limited

Yasuo Nakagawa

Tsutomu Nakamura

Keizo Shimada

Hiroshi Mera

Takashi Noma

Toshio Nishihara

Masahiro Yamaguchi

Shuji Ozawa

Osamu Kai

Kichiro Matsuda

Hideki Yunoki

Mitsuyuki Ohno

An aromatic polyamide fiber having an excellent dyeing property has a core-in-sheath type structure, in which the core portion is insoluble and the sheath portion is soluble in N-methyl-2-pyrrolidone at 35.degree. C.

Core-in-sheath type aromatic polyamide fiber and process for producing

A wholly aromatic polyamide composition which is suitable for producing filaments or fibers having not only an excellent heat-resisting property but also, a superior dyeing property, which comprises:

Wholly aromatic polyamide blend composition

An aromatic polyamide having a high degree of polymerization is produced by polymerizing

Process for producing polyamides with lactam or urea solvent and CaCl.sub.2

A novel fiber- or film-forming high-molecular-weight aromatic copolyamide consisting essentially of (1-A) a diamine recurring unit of the formula ##STR1## such as 3,4'-diaminodiphenyl ether or 3,4'-diaminodiphenyl sulfone, (1-B) a diamine recurring unit of the formula --HN--Ar.sub.1 --NH-- such as p-phenylene diamine, and (2) a dicarboxylic acid recurring unit of the formula --OC--Ar.sub.2 --CO-- such as terephthaloyl dichloride, wherein Y.sub.1, Ar.sub.1 and Ar.sub.2 are as defined in the specification, the total amount of recurring units (1-A) and (1-B) being substantially equimolar to recurring unit (2), and the proportion of recurring unit (1-A) being 7.5 to 40 mole% of the entire recurring units. The copolyamide is well soluble in solvents to give solutions having good flowability and stability that can afford shaped articles with superior thermal stability, fire retardancy and mechanical properties. A process for preparing the copolymer, and a dope of the copolymer are also provided.

Novel aromatic copolyamides prepared from 3,4' diphenylene type

An anisotropic aromatic polyamide dope comprising more than 10% by weight of an aromatic polyamide and a solvent for the polyamide, said polyamide consisting essentially of, at least 5 mole% but less than 35 moles%, based on its entire units, of an only partially p-oriented structural unit expressed by the following formula ##STR1## wherein Ar.sup.1 is a divalent aromatic ring whose chain-extending bonds are coaxial or parallel, X is a member selected from the group consisting of O, S and NH, and the NH group bonded to the benzene ring of the above benzoxazole, benzothiazole or benzimidazole ring is meta or para to the carbon atom of said benzene ring.

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Iwakuni, Japan

Yasuo Nakagawa