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:
Dec. 25, 1990
Filed:
Jun. 14, 1990
Tsutomu Okita, Kanagawa, JP;
Yutaka Kakuishi, Kanagawa, JP;
Fuji Photo Film Co., Ltd., Kanagawa, JP;
Abstract
A process for producing a magnetic recording medium is disclosed, comprising steps of (1) kneading ferromagnetic fine powders and binders with solvents, (2) optionally adding further the binders and the solvents to disperse the powders and (3) coating the resulting magnetic coating composition on a non-magnetic support, wherein the ferromagnetic fine powders have a crystallite size of not larger than 500 .ANG., the binders have at least one polar group selected from the group consisting of --SO.sub.3 M, --OSO.sub.3 M, --PO.sub.3 M.sub.2, --OPO.sub.3 M.sub.2 and --COOM (wherein M is hydrogen atom, an alkali metal or ammonium) and at least one epoxy group in the molecule and a step of adding a fatty acid having 12 to 26 carbon atoms is carried out after the dispersing step (2). Preferably, a step of crushing the ferromagnetic powders is additionally carried out before the kneading step (1).