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. 26, 1986
Filed:
Mar. 11, 1985
Masaaki Itoi, Sodegaura, JP;
Masakatsu Ohta, Sodegaura, JP;
Taizo Sugioka, Sodegaura, JP;
Kunio Yoshihara, Sodegaura, JP;
Hiroshi Nishitani, Kisarazu, JP;
Idemitsu Kosan Company Limited, Tokyo, JP;
Abstract
The invention provides a novel pitch material useful as a base material of carbon fibers having excellent mechanical properties and characterized by a unique combination of several property parameters including the content of the optically anisotropic phase of at least 80%, a content of the pyridine-insoluble matter in the range from 30 to 70% by weight, a number average molecular weight in the range from 1000 to 1400 and a softening point in the range from 330.degree. to 380.degree. C. Such a pitch material is obtained from a starting pitch of a petroleum-based residual oil freed from light oily matter through a two-step heat treatment, of which the first step is performed at 400.degree. to 460.degree. C. under a pressure of 5 to 50 mmHg and the second step is performed at 450.degree. to 550.degree. C. for 0.2 to 30 minutes under a pressure of 0.1 to 5 mmHg. The advantages obtained by use of a film evaporator in the above mentioned heat treatment are described. The time taken for the infusibilization treatment of the pitch filaments is greatly decreased when the filaments were prepared from the inventive pitch material by spinning in comparison with conventional pitches and the spinning temperature can also be relatively low.