[54] CARBON FIBER MADE FROM ACRYLIC FIBER AND PROCESS FOR PRODUCTION THEREOF
[75] Inventors: Yoji Matsuhisa, Iyo; Torn
Hiramatsu, Matsuyama; Kazuo
Yoshida, Akigawa; Gen Katagiri,
Otsu, all of Japan
[73] Assignees: Toray Industries, Inc.; Toray
Research Center, Inc., Japan
[21] Appl. No.: 899,952
[22] Filed: Jnn. 17,1992
Related U.S. Application Data
[63] Continuation of Ser. No. 456,317, Dec. 26, 1989, abandoned.
[30] Foreign Application Priority Data
Dec. 26, 1988 [JP] Japan 63-329940
Sep. 27, 1989 [JP] Japan 1-256024
[51] Int. C1.5 B32B 9/00; D02G 3/00
[52] U.S. CI 428/367; 428/364;
428/372; 428/379; 428/400; 423/447.2;
423/447.4
[58] Field of Search 428/367, 400;
423/447.2, 447.4
[56] References Cited
U.S. PATENT DOCUMENTS
Re. 33,537 2/1991 Hiramatsu et al 423/447.2
3,925,524 12/1975 Kimmel et al 423/447.4
4,024,227 5/1977 Kishimoto et al 423/447.4
4,600,572 7/1986 Hiramatsu 423/447.2
Primary Examiner—Patrick J. Ryan
Assistant Examiner—J. M. Gray
Attorney, Agent, or Firm—Austin R. Miller
[57] ABSTRACT
Disclosed is a carbon fiber made from an acrylic fiber, the carbon crystal of which has a crystal size Lc of 15 to 65 A as determined by the wide angle X-ray diffractometry. This carbon fiber has regions with a lower crystallinity in the surface layer portion thereof than that of the central portion thereof, and the compressive strength cre/(GPa) of the single filament thereof determined by the loop method satisfies formula (I):
