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:
May. 12, 1992
Filed:
Apr. 25, 1988
Hiroo Inaba, Kanagawa, JP;
Takeshi Kakuta, Kanagawa, JP;
Koichi Yamauchi, Kanagawa, JP;
Akihiro Matsufuji, Kanagawa, JP;
Fuji Photo Film Co., Ltd., Kanagawa, JP;
Abstract
A magnetic recording medium comprising a nonmagnetic support having provided thereon a magnetic layer comprising a ferromagnetic powder dispersed in a binder, wherein said ferromagnetic powder has a specific surface area of 40 m.sup.2 /g or more as measured by the BET method; said magnetic layer further comprises Al.sub.2 O.sub.3 particles having an average particle diameter of from about 0.1 to 0.5 .mu.m; and said binder comprises the combination of (1) a vinyl chloride resin containing a phosphate ester group represented by ##STR1## wherein M.sub.1 and M.sub.2, which may be the same or different, each represents Na, K, Li, H, N.sym.R.sub.3, or N.sym.HR.sub.2 wherein R represents an alkyl group or a hydrogen atom, and (2) at least one resin other than said vinyl chloride resin containing at least one of --SO.sub.3 M, --OSO.sub.2 M, --COOM, and ##STR2## wherein M, M.sub.1, and M.sub.2, which may be the same or different, each represents Na, K, Li, H, N.sym.R.sub.3, or N.sym.HR.sub.2 wherein R represents an alkyl group or a hydrogen atom; provided that the weight ratio of said resin other than said vinyl chloride resin to said vinyl chloride resin is from about 0.4 to 2.5.