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:
Apr. 15, 2008
Filed:
Apr. 02, 2003
Kazuyuki Matsumoto, Okayama, JP;
Kenichi Inoue, Okayama, JP;
Ken Inoue, Okayama, JP;
Dowa Electronics Materials Co., Ltd., Tokyo, JP;
Abstract
A powder for an underlayer of a coating-type magnetic recording medium comprises acicular iron oxide particles having an average major axis length in the range of 20-200 nm, has a specific surface area measured by the BET method of 30-100 m/g and has a powder pH of not greater than 7. The underlayer powder preferably contains 0.1-5.0 wt. % of P and optionally contains an amount of R (where R represents one or more rare earth elements, defined as including Y) such that R/Fe expressed in atomic percentage (at. %) is 0.1-10 at. %. The iron oxide powder enhances the properties required of a powder for forming the underlayer of a multi-layer structure coating-type magnetic recording tape, most notably the surface smoothness and strength of the tape.