Fuji Photo Film Company, Limited

Kunihiko Sano

Makoto Nagao

Yasuo Nishikawa

Akira Nahara

Fusao Yamanaka

Hiroaki Doushita

Hiroyuki Iwasaki

Kiyomi Ejiri

Tadashi Yasunaga

Toshio Ishida

Kazuyuki Usuki

Hiroyuki Tahara

Takashi Yoneyama

Jun Nakagawa

Mikihiko Kato

Toshio Kawamata

Yasushi Endo

Makoto Kashiwaya

Junji Nakada

Shiro Kaneko

A magnetic recording medium 101 constituted by a nonmagnetic support 101 made from a high polymer film having a thickness in a range of from 10 .mu.m to 200 .mu.m, a nonmagnetic subbing layer 102 made from a Cr alloy and formed on at least one of opposite surfaces of the nonmagnetic support 101 in the form of a film by sputtering, and a magnetic layer 103 made from a Co alloy and formed on the nonmagnetic subbing layer 102 in the form of a film by sputtering. Preferably, the magnetic recording medium 101 further has a protective layer 104 made from diamond-like carbon, and a lubricating layer 105 made from a hydrocarbon or fluorocarbon lubricant.

Magnetic recording medium

A magnetic recording medium excellent in running properties, durability and shelf stability. The magnetic recording medium has a magnetic layer of a ferromagnetic metal thin film formed over at least one surface of a non-magnetic base, with or without an inorganic protective layer formed on the magnetic layer. A surface layer consisting essentially of a salt of a phosphoric alkyl ester compound with an alkylamine compound, which is represented by the following formula (1) or (2), and a fluorine-containing carboxylic acid ester compound is provided on the magnetic layer or on the inorganic protective layer: ##STR1## where: R.sup.1 and R.sup.2, which may be the same or different from each other, are a hydrocarbon or fluorinated hydrocarbon group having from 2 to 26 carbon atoms; R.sup.A, R.sup.B, R.sup.C and R.sup.D are hydrogen, or a hydrocarbon or fluorinated hydrocarbon group having not more than 26 carbon atoms; and m is 1 or 2.

The present invention provides a magnetic recording medium, which comprises a salt of a perfluoropolyether modified with phosphoric acid at molecular terminal and an alkylamine on a magnetic layer having a ferromagnetic metal thin film at least on one side of a non-magnetic support member or a protective film formed on the magnetic layer, and it shows excellent properties under any operating conditions including low temperature and low humidity.

Magnetic recording medium comprising a ferromagnetic metal thin film,

A metal thin film magnetic recording medium having improved S/N and reduced noise is disclosed, which has a ferromagnetic metal thin film composed mainly of Co on a non-magnetic support, characterized in that the crystallite size as determined from the thin film X-ray diffraction method is 45 .ANG. (angstrom) or less relative to the (100) face of .alpha.-Co, and 120 .ANG. or less relative to the (002) face of .alpha.-Co.

A novel magnetic disc and process for the preparation thereof is disclosed, comprising a nonmagnetic support having thereon a magnetic layer comprising ferromagnetic metal particles and a binder resin containing at least a vinyl chloride copolymer, wherein the crystallite size of the ferromagnetic metal particles as determined by X-ray diffraction method is 300 .ANG. or less, and the ratio .alpha. at the surface of the magnetic layer of the integrated intensity of the Cl-2P spectrum as determined by X-ray photoelectron spectroscopy to that of the Fe-2P(3/2) spectrum is in the range of from 0.50 to 0.90. In a preferred embodiment, the vinyl chloride copolymer contains 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, and --CO.sub.2 M wherein M represents hydrogen, an alkali metal or ammonium and at least one epoxy ring in the copolymer molecule.

Magnetic recording medium in the form of a floppy disc having a magnetic

A magnetic recording medium comprising a non-magnetic support having thereon a magnetic layer, wherein said magnetic layer contains (a) an oxo acid having a hydrocarbon group or a salt thereof, and (b) a fluorinated polyether.

Magnetic recording medium comprising a ferromagnetic metallic then film

A magnetic disk comprising a non-magnetic support having provided thereon a magnetic layer comprising ferromagnetic particles, and a binder resin, wherein said magnetic layer is such that when sputtering is conducted on said magnetic layer from the surface of the magnetic layer in the direction of the depth of the magnetic layer by the Auger electron spectroscopic method, and the concentration of carbon atoms resulting from the sputtering is measured, a sputtering time (T.sub.1) required for the carbon atom concentration to be (C.sub.0 +C.sub.2)/2 is in the range of from 8 to 98 minutes, wherein C.sub.0 is a carbon atom concentration value obtained at the initiation of the sputtering and C.sub.2 is a carbon atom concentration value after the carbon atom concentration becomes constant.

Magnetic disk

A magnetic recording medium is disclosed, which comprises a non-magnetic support having thereon a magnetic layer comprising ferromagnetic fine particles and a binder containing a vinyl chloride polymer, wherein the crystalline size of the ferromagnetic fine particles is from 350 to 500 angstrom, the content of the vinyl chloride polymer is from 20 to 50% by weight based on the amount of the total binder, and an integrated intensity ratio .alpha. of the Cl-2P spectrum to the Fe-2P (3/2) spectrum at the surface of the magnetic layer measured by an X-ray photoelectron spectroscopy is 1.80/1&gt;.alpha.&gt;0.50/1.

Magnetic recording medium containing ferromagnetic particles with

A magnetic recording medium is disclosed, comprising a non-magnetic support having thereon a magnetic layer comprising ferromagnetic particles and a binder containing a vinyl chloride polymer, wherein the crystallite size of the ferromagnetic particles is 250 angstrom or less, the vinyl chloride polymer is present in an amount of 20 to 50% by weight based on the binder, and an integrated intensity ratio, which is denoted by .alpha., of Cl-2P spectrum to Fe-2P (3/2) spectrum in the surface of the magnetic layer as measured by X-ray photoelectron spectroscopy is 0.20/1&lt;.alpha.&lt;0.42/1. The magnetic recording material exhibits excellent running property and durability and hardly causes head clogging.

A magnetic recording medium comprising a non-magnetic support having a magnetic layer thereon, wherein the surface of the magnetic layer contains (a) a first fluorinated polyether having an oxo acid group or an oxo acid salt group at one or both terminals thereof, and (b) a second fluorinated polyether having a group selected from a alkoxycarbonyl group, an acyloxy group and a hydroxyl group at one or both terminals thereof, or the polyether (a) and polyether (b) are incorporated into the magnetic layer.

Magnetic recording medium lubricant comprising two different fluorinated

A method for making a magnetic recording medium comprises the steps of forming a thin ferromagnetic metal film on a non-magnetic substrate. The thin ferromagnetic metal film contains Co as a main constituent and contains oxygen in a proportion of at least 15 at %. Thereafter, the thin ferromagnetic metal film is exposed to an ozone-containing atmosphere. A magnetic recording medium is thereby obtained, which exhibits excellent resistance to corrosion with salts and good electromagnetic transducing characteristics.

Method for making magnetic recording media

A magnetic recording medium comprising a nonmagnetic support having thereon a magnetic layer, wherein an ester compound obtained by condensing a saturated fatty acid having from 6 to 26 carbon atoms and an unsaturated alcohol having from 8 to 26 carbon atoms is present on or in the magnetic layer.

A perpendicular magnetic recording medium such as a floppy disk is created by providing on at least one surface of a non-magnetic support, a magnetic layer having perpendicular magnetic anisotropy and a protective layer by sputtering. First, a magnetic layer is provided, secondly, the magnetic layer is surface treated by a plasma treatment or by applying an oxide layer or a nitride layer thereon and thirdly, the protective layer is applied thereto.

Perpendicular magnetic recording medium and the method for preparing the

A method of preparing a magnetic recording medium in which a magnetic layer is deposited on a non-magnetic support and then a carbon protective layer is sputtered onto the magnetic layer. The sputtering is performed with a bias voltage of -10V to -100V being applied in the vicinity of the support and magnetic layer.

Method for preparing a magnetic recording medium

A magnetic recording medium is described, comprising a non-magnetic support having provided thereon a thin magnetic metal film and a protective layer mainly comprising carbon having a graphite structure containing at least one element selected from the group consisting of Mn, Mo, Nb, Ta, Ti, V, Cr and W.

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Kanagawa, Japan

Kunihiko Sano