US 11,891,478 B2
Liquid crystal polyester fibers
Yusaku Kohinata, Tokyo (JP)
Assigned to SUMITOMO CHEMICAL COMPANY, LIMITED, Tokyo (JP)
Filed by SUMITOMO CHEMICAL COMPANY, LIMITED, Tokyo (JP)
Filed on Aug. 30, 2021, as Appl. No. 17/461,359.
Application 17/461,359 is a division of application No. 16/961,590, granted, now 11,370,881, previously published as PCT/JP2019/000185, filed on Jan. 8, 2019.
Claims priority of application No. 2018-006322 (JP), filed on Jan. 18, 2018.
Prior Publication US 2021/0388157 A1, Dec. 16, 2021
Int. Cl. C08G 63/60 (2006.01); D01F 6/84 (2006.01)
CPC C08G 63/605 (2013.01) [D01F 6/84 (2013.01); D10B 2401/063 (2013.01)] 2 Claims
 
1. A liquid crystal polyester fiber comprising:
a liquid crystal polyester,
wherein a tensile strength is 25 cN/dtex to 30 cN/dtex, and an orientation degree of the liquid crystal polyester in a length direction of the fiber is 94% to less than 100%,
wherein the liquid crystal polyester has a repeating unit represented by Formula (1), a repeating unit represented by Formula (2), and a repeating unit represented by Formula (3),
at least one repeating unit selected from the group consisting of the repeating unit represented by Formula (1), the repeating unit represented by Formula (2), and the repeating unit represented by Formula (3) contains a 2,6-naphthylene group,
a content of the repeating unit containing the 2,6-naphthylene group is 68 mol % to 80 mol % with respect to a total content of all the repeating units of the liquid crystal polyester, and
the liquid crystal polyester fiber has a fiber diameter of 5 μm to 100 μm,
—O—Ar1—CO—  (1),
—CO—Ar2—CO—  (2), and
—X—Ar3—Y—  (3),
wherein Ar1 represents a phenylene group, a naphthylene group, or a biphenylylene group, Ar2 and Ar3 each independently represent a phenylene group, a naphthylene group, or a biphenylylene group, at least one selected from the group consisting of Ar1, Ar2, and Ar3 contains a 2,6-naphthylene group, X and Y each independently represent an oxygen atom or an imino group (—NH—), and hydrogen atoms of the group represented by Ar1, Ar2, or Ar3 are optionally each independently substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.