The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 06, 1991
Filed:
Nov. 17, 1989
Teruo Iwashita, Kawasaki, JP;
Yutaka Arai, Kawasaki, JP;
Hirofumi Sunago, Kawasaki, JP;
Tadao Tomioka, Kawasaki, JP;
Nippon Steel Corporation, Tokyo, JP;
Nippon Steel Chemical Co., Ltd., Tokyo, JP;
Abstract
In a method of producing mesophase pitch based carbon fibers, including the steps of melt-spinning a mesophase pitch through a nozzle (1) having at least one pair of a counter-bore (2) and a circular capillary (3) to form a pitch fiber and subjecting the pitch fiber to an infusible treatment, a carbonization treatment, and if necessary, a graphitization treatment, to form a carbon fiber, the nozzle has a degree of asymmetry .phi. of from 0.1 to 0.9, .phi. being defined by the following equation .phi.=S.sub.A /S.sub.B, wherein S.sub.A is an area of an inscribed circle in a contour of the cross-section of the counter-bore, which circles is perpendicular to the nozzle axis and has a center on the axis of the capillary and inscribed and S.sub.B is a total area of the cross-section of the counter-bore.