JP2605380B2 - Magnetic recording media - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic recording medium using a ferromagnetic metal thin film suitable for high-density magnetic recording as a magnetic recording layer.

Conventional technology Voice by helical scanning method using rotating magnetic head,
The technology of recording and reproducing images is one of the magnetic recording methods.
Recording density is increasing. Therefore, in order to further shorten the wavelength in the future, a magnetic recording medium with a new configuration is required.
On a non-magnetic substrate such as a polymer film, a perpendicular magnetic film obtained by a Co-Cr sputtering method, or a vapor deposition tape having a Co-Ni-O oblique vapor deposited film is promising (for example,
Foreign Transactions, IEEE TRANSACT10NS ON MAGNETICS Vol.MAG
-21, NO-3, PP1217-1220 (1985)].

FIG. 2 is an enlarged cross-sectional view of one example of a vapor deposition tape. In FIG. 2, 1 is a polymer film such as a polyethylene terephthalate film having an undercoat layer for providing irregularities as necessary. 2 is from 0.05 μm to 0.3 μm formed by electron beam evaporation, high frequency sputtering, etc.
A magnetic recording layer made of a ferromagnetic metal thin film having a thickness of about m is a protective lubricating layer, which can be appropriately selected from those proposed for many purposes such as lamination of an amorphous carbon film and fluorine oil. Reference numeral 4 denotes a back coat layer, which is a coating layer made of a resin containing a filler, a lubricant and the like for assisting the running property (Japanese Patent Publication No. 56-23,208;
41418, JP-A-61-151835, JP-A-61-187
No. 122, etc.].

Magnetic tapes are also characterized by their ability to increase the volume recording density, and as a means of long-term recording, the trend of tape thinning is also important.
At present, development is progressing in favor of thinning.

Certainly, the magnetic recording layer is 1/10 of the conventional coating type magnetic layer.
It is thought that the thickness is as thin as possible and the Young's modulus of the magnetic recording layer is more than 10 times larger, so it is thought that the overall thickness can be reduced.However, when aiming for practical use in a wide temperature range, the bimetal structure has a disadvantage. Because a special surface is conspicuous, a tape configuration in which a vapor deposition layer is disposed on both surfaces has been proposed (Japanese Patent Laid-Open No. 61-11 / 1986).
No. 0343).

FIG. 3 is an example of an enlarged cross-sectional view of a double-sided deposition type magnetic tape. FIG. 3 is a polymer film, such as a polyethylene terephthalate film having worm-like irregularities on both surfaces. 6 is a magnetic recording layer made of a ferromagnetic metal thin film such as a perpendicular magnetic film, the oblique deposition film, 7 if a double-sided access type, and consists of a ferromagnetic metal thin film, in the case of single-sided access, SiO, SiO ₂ , Al ₂ O ₃ , MgF _2, etc., a non-magnetic thin film formed by a method such as reactive vapor deposition or high frequency sputtering, and 8 is a protective lubricating film.

Problems to be Solved by the Invention However, in the above configuration, the total thickness is 10 μm or less,
When applied to high-density recording / reproducing applications, image quality deterioration due to jitter is a problem in view of the demands of recent recording techniques which have insufficient durability and particularly high image quality, and improvements have been desired.

The present invention has been made in view of the above-described circumstances, and provides a thin magnetic tape that stabilizes running performance even in repeated use and does not deteriorate image quality due to jitter.

Means for Solving the Problems To solve the above-mentioned problems, the magnetic recording medium of the present invention comprises a polymer film in which a ferromagnetic metal thin film, a diamond-like carbon film, and a lubricating layer are laminated, and a graphite film is formed in the other. It is intended to be arranged.

Effect The magnetic recording medium of the present invention has a stable running property on the back surface and a stable running property because the lubricant is almost uniformly transferred to the both sides to maintain an equilibrium state by the above configuration. Will be. In particular, during high-speed running and sliding with the head, the lubricant layer on the ferromagnetic metal thin film side is reduced, but durability is secured because it is constantly replenished from the opposite side.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention. In FIG. 1, 9 is a polyethylene terephthalate, polyethylene naphthalate, polyether ether ketone, polyphenylene sulfide, polyether having a thickness of 9 μ or less. Polymer films such as sulfon, polyamide, polyimide, etc., 10 and 11 are earthworm-like undercoat layers composed of water-soluble polymers or undercoats with fine particles such as SiO ₂ , TiO ₂ , CaCO ₃ , ZnO, polyethylene spheres 12 is Co, Co-Cr, Co-O,
Co-Ni, Co-Fe, Co-Ta, Co-Mo, Co-W, Co-Nd, Co-Cr-N
b, Ferromagnetic metal thin film of Co-Ni-O etc.
A range of 0 ° is preferable, and a multilayer structure may be employed, and it can be formed by an electron beam evaporation method, an ion plating method, a sputtering method, or the like. Reference numeral 13 denotes a diamond-like carbon thin film, which is a known method such as a sputtering method, an ion beam deposition method, or the like.
(See September 1987, pp. 46-55).
The diamond thin film may be a diamond thin film, but a diamond-like hard carbon film is suitable from the industrial viewpoint because the film formation rate is low. Reference numeral 14 denotes a graphite thin film formed by sputtering using carbon as a target, and preferably has a thickness of 1000 to 3000 mm.

15 is divided into 15A and 15B by a lubricant and arranged on both sides.Even after manufacture, the tape is used to maintain the equilibrium state by transfer, so that fatty acids, fatty acid esters, perfluorocarboxylic acid, What arrange | positioned fluoropolyether etc. by the solution coating method, the vacuum evaporation method, etc. is used.

Hereinafter, an example of the present invention will be described more specifically in comparison with a comparative example.

Example -1 on one surface of a polyethylene terephthalate film having a thickness 8.8μm diameter 90 Å Eu ₂ O ₃ fine particles 15 Ke / ([mu] m)
Undercoat layer of density ² ; 400 mm diameter Al ₂ O _{3 on the} other side
3 particles / (μm) ^{2 are} arranged, and a minimum incidence angle of 48 degrees is set along a cylindrical can with a diameter of 1 m on the surface on which the Eu ₂ O ₃ particles are arranged.
Electron beam deposition of Co-Ni (Co: 80 wt%) at an oxygen partial pressure of 8 × 10 ^-5 (Torr) to form a Co-Ni-O film of 1400Å, and a graphite target thereon, Ar + H ₂ = 0.09 (Tor
r) AriH ₂ = 1: _2, 13.56 (MHz) 900 (W), a diamond-like hard carbon film is distributed by 100 ° by sputtering, and CH ₄ gas is discharged and decomposed on the other surface, and a graphite thin film is disposed by 1550 °. Then, 160 ° of perfluorostearic acid was arranged on the diamond-like hard carbon thin film side by a vacuum evaporation method, and processed into an 8 mm wide tape. The tape is 12 in 8 mm cassette.
A 0 m winding was performed, and aging was performed at 50 ° C. for 1 W.

Arrange fine particles on the same film as in Example -2 Example -1, the Eu ₂ O ₃ particles side by high-frequency sputtering method, along a cylindrical Quillan diameter 50cm, Co-Cr (Co: 80wt%) Vertical A magnetized film was placed at 1400 °, a diamond-like hard carbon film was placed at 100 ° on the same manner as in Example-1, a graphite thin film was placed at 1450 ° on the other surface, and perfluoroarachinic acid was placed at 180 ° as a lubricant. And a tape having a width of 8 mm was wound into a cassette under the same conditions as in Example 1 and aged.

Comparative Example -1 A carbon fine particle and CaCO ₃ at a weight ratio of 2: 1 on the film surface on the opposite side of the Co-Ni-O thin film in Example 1 and a 1: 1 weight ratio with respect to the polyester resin. An 8 mm cassette tape was prepared under the same conditions except that the coat was provided.

In Comparative Example -2 Example -2 0.1 instead of graphite film, a CH ₄ gas and B to the target as a discharge gas (Torr), 13.
12 BC film by sputtering at 56 (MHz) 800 (W)
An 8 mm cassette tape was prepared under the same conditions as above except that the tape was arranged at 00 °.

The results of examining the number of times the tape was repeatedly recorded and reproduced with an 8 mm video modified to the high band specification until the jitter level exceeded an allowable level by visual observation were shown in a table. In the running mode, comparisons were made in such a way that the entire length was recorded, rewinding and reproduction were checked, and then left for 3 hours before rewinding to rewind and reproduce.

Effects of the Invention As described above, according to the present invention, there is an excellent effect that a thin magnetic recording medium excellent in high-density recording performance having good running properties and good repeated durability can be provided.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of an embodiment of the magnetic recording medium of the present invention, and FIGS. 2 and 3 are enlarged sectional views of a conventional magnetic recording medium. 9: Polymer film, 10, 11: Undercoat layer, 12: Ferromagnetic metal thin film, 13: Diamond-like carbon film, 14: Graphite film, 15A, 15B: Lubricant.

Claims (1)

(57) [Claims] 1. A magnetic recording medium characterized in that a ferromagnetic metal thin film, a diamond-like carbon film and a lubricating layer are laminated on one surface of a polymer film, and a graphite film is disposed on the other surface.