Toyo Boseki Kabushiki Kaisha

Kohei Kiriyama

Tooru Kitagawa

Yoshihiko Teramoto

Takaharu Ichiryu

Hiroki Murase

Tadao Kuroki

Seiji Watanuki

Yukihiro Nomura

Yukinari Okuyama

Yusuke Shimizu

Go Matsuoka

Hiroshi Tachimori

Muneatsu Nakamura

Hironori Eguchi

Yukihiro Abe

To provide fibers which retain the excellent heat resistance and flame retardancy inherent in polybenzazole fibers and pyridobisimidazole fibers, have improved post-processability and neither necessitate considerable change in production process conditions nor require a high-temperature and long-time heating treatment. With respect to the polybenzazole fiber and pyridobisimidazole fiber, in an electron diffraction diagram of a surface layer part (from the surface to 1 &#x3bc;m) of the fibers, the fibers containing a crystal present in a state satisfying that S2/S1 is in a prescribed range, wherein S1 is a diffraction peak area derived from a crystal (200) plane and S2 is a diffraction peak area derived from a plurality of other crystal planes along an equatorial direction profile.

Polybenzazole fiber and pyridobisimidazole fiber

The present invention relates to polybenzazole fibers or filaments, staple fibers, spun yarns, and woven or knitted fabrics containing in themselves an organic pigment having heat resistance as high as a thermal decomposition temperature of 200&#xb0; C. or higher, and soluble in a mineral acid and having group(s) of &#x2014;N&#x2550; and/or NH&#x2014; in the molecule, such as any of perinones and/or perylenes, any of phthalocyanines, any of quinacridones, and any of dioxazines, wherein they have a strength retention of 50% or higher when exposed to light from a xenon lamp for 100 hours and having a tensile strength retention of 85% or higher after exposed to an atmosphere of a temperature of 80&#xb0; C. and a relative humidity of 80% for 700 hours. The polybenzazole fibers or filaments, staple fibers, spun yarns, and woven or knitted fabrics can be used for cords for reinforcing rubber, sheets and rods for reinforcing cement/concrete, composite materials, sail clothes, ropes, knife proof vests and bullet proof vests.

Polybenzazole fiber and use thereof

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Ohtsu, Japan

Kohei Kiriyama