Mitsubishi Chemical Corporation

Takayuki Kiriyama

Nobuyuki Yamamoto

Takayuki Kobayashi

Atsushi Nakajima

Kenichi Watanabe

Naoki Sugiura

Takuya Teranishi

Masahiro Ichino

Naoki Aoyama

Yoshiko Irie

Kiharu Numata

Masahiro Hata

Yasuyuki Fujii

Norifumi Hirota

Takeshi Nii

Tadashi Ohtani

Yuusuke Shinmen

Hiroyuki Nakao

Hiroshi Tategaki

Harumi Matsuda

Masashi Shimahara

Yasunori Murano

Yukio Nishimoto

Shigekazu Takeda

Toshiyuki Itou

Akiyoshi Kogame

Provided are carbon fiber bundles which have high knot strength even if the single fiber fineness is large, and which have excellent handling properties and processability. The carbon fiber bundles have a single fiber fineness of 0.8-2.5 dtex, knot strength of 298 N/mmor greater. This method of producing carbon fibers having knot strength of 298 N/mmor greater involves a heat treatment step for heat treating, for 50-150 minutes, specific polyacrylonitrile-based precursor fiber bundles described in the description in an oxidizing atmosphere rising in temperature in the temperature range of 220-300° C.

Carbon fiber bundle and method of producing carbon fiber bundle

Provided are carbon fiber bundles which have high knot strength even if the single fiber fineness is large, and which have excellent handling properties and processability. The carbon fiber bundles have a single fiber fineness of 0.8-2.5 dtex, knot strength of 298 N/mmor greater. This method of producing carbon fibers having knot strength of 298 N/mmor greater involves a heat treatment step for heat treating, for 50-150 minutes, specific polyacrylonitrile-based precursor fiber bundles described in the description in an oxidizing atmosphere rising in temperature in the temperature range of 220-300&#xb0; C.

Provided are carbon fibers which have a thicker single fiber fineness of the polyacrylonitrile-based precursor fiber bundles and lower production costs, and which have excellent mechanical properties. Also provided are: carbon fiber bundles having a single fiber fineness of 0.8-2.1 dtex, a strand strength of 4.9 GPa or greater, and a strand elastic modulus of 200 GPa or greater; carbon fiber bundles having a single fiber fineness of 0.8-2.5 dtex, a strand strength of 3.0 GPa or greater, and a strand elastic modulus of 240 GPa or greater; and an optimal method for producing said carbon fiber bundles. carbon fiber bundles having a single fiber fineness of 0.8-2.5 dtex, a strand strength of 3.0 GPa or greater, and a strand elastic modulus of 240 GPa or greater; and an optimal method for producing said carbon fiber bundles.

Carbon fiber bundle and method of producing carbon fibers

Provided are: chopped carbon fiber bundles which have high fluidity without decreasing the dispersibility of carbon fibers and the physical properties of a molded product; and a method for producing chopped carbon fiber bundles with high productivity. Chopped carbon fiber bundles, each of which contain a carbon fiber bundle having a total fineness of from 25,000 dtex to 45,000 dtex (inclusive) and a sizing agent in an amount of from 1% by mass to 5% by mass (inclusive) relative to the total mass of the chopped carbon fiber bundle. The length (L) of each chopped carbon fiber bundle along the fiber direction of the carbon fiber bundle is from 1 mm to 50 mm (inclusive); the ratio of the longest diameter (Dmax) to the shortest diameter (Dmin) of a cross section perpendicular to the fiber direction of each chopped carbon fiber bundle, namely Dmax/Dmin is from 6.0 to 18.0 (inclusive); and the orientation parameter of the single fibers present in the surface of each chopped carbon fiber bundle is 4.0 or less.

Chopped carbon fiber bundles and method for producing chopped carbon fiber bundles

Provided is a carbon fiber manufacturing method including a surface treatment step of ejecting an ozone solution in which ozone is dissolved in solvent from a fluid ejecting port toward a carbon fiber bundle and causing the ozone solution to pass between single fibers of the carbon fiber bundle so as to contact surfaces of the single fibers so that the surfaces of carbon fibers are treated by the ozone solution. Also, provided is a carbon fiber subjected to a surface treatment by the carbon fiber manufacturing method.

Carbon fiber manufacturing method and carbon fiber

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Toyohashi, Japan

Takayuki Kiriyama