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:
Nov. 19, 1991
Filed:
Mar. 28, 1990
Makoto Inoue, Miyagi, JP;
Hiroshi Miura, Miyagi, JP;
Kaneaki Niita, Miyagi, JP;
Toshiyuki Sano, Miyagi, JP;
Yoshitaka Tsukidate, Miyagi, JP;
Takahiro Miyazaki, Miyagi, JP;
Sony Corporation, Tokyo, JP;
Abstract
A magnetic recording medium improved in electromagnetic conversion characteristics and runnability is disclosed. The magnetic recording medium is formed by coating a non-magnetic substrate with a magnetic layer. The magnetic layer contains a fine ferromagnetic powder having a specific surface area larger than 45 m.sup.2 /g, a binder having polar groups such as --SO.sub.3 M and --OSO.sub.3 M in the molecule in an amount of 0.2 to 0.8 .mu.mol per m.sup.2 of the specific surface area of the ferromagnetic powder, and a compound having 2 or more carboxylic groups in an amount of 0.5 to 5.0 .mu.mol per m.sup.2 of the specific surrface of the ferromagnetic powder. The magnetic layer is further incorporated with a carbon powder having a mean diameter of 200 to 400 nm and a specific surface area of 5 to 20 m.sup.2 /g to improve the runnability of the magnetic recording medium while keeping the improved magnetic characteristics.