Process for producing a coil-shaped carbon fiber bundle
AssigneesKoa Oil Company, Limited, Tanaka Kikinzoku Kogyo K.K.
InventorsEiji Kitajima, Takashi Oyama, Eiji Maruden, Hirokazu Teraoka, Haruki Yamasaki, Susumu Shimizu
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Abstract
The present invention relates to a carbon fiber bundle comprising a regular coil-shaped fiber bundle and having excellent stretch characteristic. A process for producing a coil-shaped carbon fiber bundle according to the present invention comprises the steps of compositing at least two kind of pitches to spin them as single fibers, bundling the thus spun single fibers to form a fiber bundle, then infusibilizing the resulting fiber bundle under tension and carbonizing the fiber bundle.
Claims9
A process for producing a coil-shaped carbon fiber bundle comprising the steps of:
- compositing at least two pitches wherein the maximum difference in coefficient of linear contraction in the direction of a fiber axis during carbonization of spun pitches is at least 5% and the difference in the softening points of the pitches to be composited is within 10.degree. C. so as to spin the thus composited pitches as single fibers;
- bundling the thus spun single fibers to form a fiber bundle;
- then infusibilizing the resulting fiber bundle under tension;
- and carbonizing the fiber bundle, wherein the stretch characteristics of the resulting coil-shaped carbon fiber bundle is controlled by adjusting one or more of the discharge proportion of the spinning pitches to be composited, the size of the diameter of fibers to be spun or the number of fibers to be bundled.
Dependencies are inferred from the claim text.