# US 5,707,742 A · Magnetic recording medium comprising a ferromagnetic metal thin film, protective layer, and an alkylamine perfluoropolyether lubricant

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- Number: US 5,707,742 A
- Document ID: US5707742A
- Status: Granted
- Kind: A
- Application number: 08/541,970
- Filed: 1995-10-10
- Granted: 1998-01-13
- Earliest claimed: 1994-10-07
- Assignees: Fuji Photo Film Co., Ltd.
- Inventors: Kazuyuki Usuki; Toshio Ishida; Kunihiko Sano
- Web page: https://patentgrep.com/patent/US5707742A

## CPC

- G11B 5/7257: {Perfluoropolyether lubricant}
- G11B 5/7266: {comprising a lubricant over the inorganic carbon coating}
- Y10S 428/90: Magnetic feature
- Y10T 428/31544: Addition polymer is perhalogenated
- Y10T 428/31678: Of metal
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

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.

## Claims

### Claim 1

A magnetic recording medium, comprising a magnetic film, the magnetic film comprising a non-magnetic support member having a ferromagnetic metal thin film on one side thereof, and a protective film laminated thereupon, whereby an alkylamine salt of a perfluoropolyether compound containing a phosphoric acid group at a molecular terminal thereof is present on a surface of the protective film, and wherein the salt of the alkylamine perfluoropolyether compound is present in an amount of from 1 to 30 mg/m.sup.2 and has one of the following chemical formulae (1) to (4): ##STR6## where A represents: ##STR7## wherein R.sup.A, R.sup.B, R.sup.C and R.sup.D each represents a hydrogen atom, a hydrocarbon group or a hydrocarbon fluoride group having 1 to 26 carbon atoms, and B represents: ##STR8## where R.sup.E, R.sup.F, R.sup.G, R.sup.H, R.sup.I and R.sup.J each represents a hydrogen atom or a hydrocarbon or a hydrocarbon fluoride group having 1 to 26 carbon atoms, and R represents an alkylene group having 1 to 26 carbon atoms;
m represents 1 or 2;
Rfa represents a monovalent perfluoropolyether group having an alkylene group at one terminal thereof; and
Rfb represents a bivalent perfluoropolyether group having alkylene groups at both terminals thereof.

### Claim 2 (depends on 1)

The magnetic recording medium of claim 1, wherein the protective film comprises a material selected from the group consisting of silica, alumina, titania, zirconia, cobalt oxide, nickel oxide, titanium nitride, silicon nitride, boron nitride, silicon carbide, chromium carbide, boron carbide, graphite and amorphous carbon.