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. 18, 1998
Filed:
Nov. 01, 1996
Akira Ishikawa, Tochigi-ken, JP;
Hidehiko Nakayama, Tochigi-ken, JP;
Kazutaka Yamashita, Tochigi-ken, JP;
Kao Corporation, Tokyo, JP;
Abstract
Magnetic recording media comprising a nonmagnetic substrate, a surface layer and a back layer, the surface layer having an intermediate layer provided on the surface side of the nonmagnetic substrate and a magnetic layer as a top layer, the back layer having a backcoating layer provided on the back side of the nonmagnetic substrate, the magnetic layer containing a ferromagnetic metal powder and a binder, wherein the surface layer has a residual solvent content of 5 to 1000 ppm, the ferromagnetic metal powder is a ferromagnetic metal powder mainly comprising iron and containing 0.8 to 20 parts by weight of at least one element selected from Group IIIa elements, inclusive of lanthanides, of the Periodic Table per 100 parts by weight of Fe atoms, the magnetic layer has a thickness of 0.05 to 0.6 .mu.m, the magnetic layer has a center-line surface roughness Ra of 1 to 5 nm, the back layer has a residual solvent content of 5 to 800 ppm, and the backcoating layer has a center-line surface roughness Ra of 2 to 8 nm, exhibit excellent electromagnetic characteristics and storage stability.