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.

Date of Patent:
Aug. 25, 1981

Filed:

Oct. 11, 1979
Applicant:
Inventors:

Yukihiro Isobe, Saku, JP;

Masashi Hayama, Usada, JP;

Kenji Hirabayashi, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01F / ; H01F / ; C04B / ;
U.S. Cl.
CPC ...
252 6254 ; 427128 ; 428900 ;
Abstract

A magnetic coating material for magnetic recording media is produced by dispersing a magnetic coating material containing from 0.1 to 2.0% of an abrasive and from 0.05 to 1.0% of a betaine type ampholytic antistatic agent, both on the basis of the amount of a magnetic powder, in a dispersion mill using steel balls. The abrasive has a hardness of not lower than 6 on Mohs' scale.


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