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:
Jun. 06, 2000
Filed:
Jun. 17, 1998
Applicant:
Inventor:
Takao Kudo, Miyagi, JP;
Assignee:
Sony Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ; G11B / ;
U.S. Cl.
CPC ...
428323 ; 428522 ; 4286 / ; 4286 / ; 4286 / ; 428900 ;
Abstract
The present invention provides a magnetic recording medium including a lower non-magnetic layer mainly consisting of a non-magnetic powder and a binder and an upper magnetic layer mainly consisting of a magnetic powder and a binder which layers are formed on a non-magnetic support body, wherein the binder of the lower non-magnetic layer is a vinyl chloride copolymer having a sulfonic acid base and/or a quaternary ammonium base and hydroxy group and epoxy group, and having an average polymerization degree of 100 to 220, and the non-magnetic powder is a non-magnetic powder having a longer axis length of 0.2 .mu.m or below and an acid surface.