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. 25, 1992
Filed:
Jun. 18, 1990
Applicant:
Inventors:
Hiroshi Umezaki, Niihama, JP;
Yoshiaki Takeuchi, Niihama, JP;
Assignee:
Sumitomo Chemical Company, Limited, Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
428329 ; 428402 ; 428403 ; 428694 ; 428900 ;
Abstract
A magnetic recording medium comprising a non-magnetic substrate and a magnetic layer which comprises magnetic powder, a binder and alumina powder having an average primary particle size of not larger than 0.3 .mu.m and containing at least one oxide selected from the group consisting of oxides of silicon, magnesium, lanthanum and zirconium in an amount of 0.05 to 5 parts by weight per 100 parts by weight of alumina, which medium has improved durability, abrasion resistance and surface smoothness of a magnetic layer and good cleaning effect on a magnetic head.