JPS6378330A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To maintain a high-density recording characteristic even in repetitive use in a wide range of environment by disposing a coated layer contg. fine carbon particles to one face of a high-polymer film and disposing a polymerized film contg. the fine carbon particles and lubricating film on a thin ferromagnetic metallic film disposed on other face. CONSTITUTION:The coated layer 8 contg. the fine carbon particles 9 is disposed on one face of the high-polymer film 6 and the polymerized film 11 contg. the fine carbon particles and the lubricating film 12 are disposed on the thin ferromagnetic metallic film 7 disposed on another face. Since the properties of both faces of the medium are approximate to each other, the lubricating is always equilibrated at a specified level by the inter-transfer and replenishment during winding. The stable running condition and durability are thus assured. The consumption of the lubricating agent is thereby decreased even in the repetitive use in the high-humidity environment and the high-density recording characteristic is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium whose magnetic recording layer is a ferromagnetic metal thin film suitable for high-density magnetic recording.

Recent advances in recording technology) have significantly improved the recording density per unit area, and the practical use of magnetic recording media includes vapor-deposited tapes whose magnetic recording layer is a ferromagnetic metal thin film with an extremely smooth surface. is strongly desired.

Therefore, there is a growing recognition that future increases in density will be premised on realistic solutions to tribological issues related to understanding friction, wear, etc. that occur when magnetic heads and magnetic recording media slide [Television Society of Japan] Magazine, VOL, 40, Ji
6 (1986) 472 pages].

FIG. 2 is an enlarged sectional view of a conventional magnetic recording medium.

In Figure 2, 1 is a non-magnetic substrate such as a polyester film or 75.1 alloy, 2 is a Co-Ni-0 obliquely deposited film, . . . is a magnetic recording layer such as a Co-Cr perpendicular magnetization film, 3 is the top coat layer, 4 is the protective layer, and 6 is the top coat layer.
is the lubricating layer.

Conventionally, the top coat layer has been expected to play a role as a protective layer, as disclosed in JP-A-54-113303, which improves abrasion resistance by depositing a fatty acid metal salt film;
A sputtered film of a polymer having an imide group as disclosed in Japanese Patent Publication No. 7-116771, an example of sputtering using a polymer compound as a target as disclosed in Japanese Patent Application Laid-open No. 58-77031, carbon, BN + MOS2, S
! Examples of thinning the film by full sputtering or vapor deposition such as 02, and examples of using a diamond-like hard carbon film (Japan Society of Applied Magnetics, 46th Research Meeting Materials) are known.

In addition, as a layer for lubricating purposes, fatty acids, fatty acid amides, etc. are deposited by vapor deposition, wet coating, etc. (for example,
30609)) have been tried in large numbers.

However, the above-mentioned examples do not fully satisfy wear resistance, runnability, anti-corrosion effect, etc., so the idea of laminating them and dividing the roles of each layer is increasing.

One in which a fluorocarbon-based lubricant layer is provided on an adsorption layer of fatty acid metal salt (JP-A-61-120331), and one in which a fluorine-containing lubricating oil layer is provided on a hard carbon layer (JP-A-61-126627). (Japanese Unexamined Patent Publication No. 131231/1989), a lubricating layer formed on a 5i-N-0 thin film
Publication No.) etc.

Problems to be Solved by the Invention However, with the above configuration, when used as a tape-like medium, the lubricant is consumed rapidly, especially when used in a high humidity environment, making it difficult to perform high-density recording. There was a problem that the necessary running stability was lost, and an improvement was desired. The present invention was made in view of the above circumstances,
The present invention provides a magnetic recording medium that can maintain high-density recording characteristics even when used repeatedly in a wide range of environments.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention has a coating layer containing fine carbon particles on one side of a polymer film, and a thin ferromagnetic metal film on the other side. A polymeric film containing carbon particles and a lubricating film are placed on top.

Function: Due to the above-described structure, the magnetic recording medium of the present invention has similar properties on both sides of the medium, so that the lubricant is always balanced to a certain level by mutual transfer replenishment during winding, so stable running is possible. This means that the condition and durability can be ensured.

EXAMPLES Below, magnetic recording media according to examples of the present invention will be described 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, where 6 is a polymer film made of a polyethylene terephthalate film with a thickness of 8.5 μm, and 7 is a polymer film that moves along a cylindrical can with a diameter of 1 m. On the film, 1x1o
(Torr) of Co at a minimum angle of incidence of 40 degrees in oxygen.
- A ferromagnetic metal thin film formed by 0.16 μm electron beam evaporation of Ni (Co: 80 wt%), 8 is a back coat layer, and carbon fine particles (particle size 450%) 9 are added by weight % to 10 of polyester resin. Thickness 0.5 with 22% dispersion
The coating layer is μm thick.

11 is a polymer film with a layer thickness of 110 people containing carbon fine particles, 12
is a lubricating film. In use, a portion of the lubricant naturally exists on the bank coat layer 8, but the film thickness was controlled in the initial coating state, and the value was set to 70A in the example.

Polymer films containing carbon fine particles can be produced by using a hydrocarbon monomer (specifically propane) as a starting material and adjusting the power of the plasma to inject it from two nozzles under fine particle conditions, or by irradiating it under film forming conditions. Using the obtained material, the average particle size was 100.

The density was 6×10 7 cells/ci, and the polymer film thickness was 66 persons. Prepare 8-wing width magnetic tape with various lubricants,
A modified 8-ho video was compared for narrow track recording performance with a track width of 7.8 μm. As a comparative example, one without a polymer film was used. Track followability was evaluated by C/N. C/
N is the signal-to-noise ratio during reproduction when recording at 75 μm, and the initial value was set to 0 (, dB).

The tested environment was 40°C, 8a% RH.

The test results are shown in the table.

In the table above, the C/N of the example has improved somewhat from the initial stage, but this is due to the head becoming more familiar with the head, while the comparative example has improved track deviation, which is thought to be due to rapid consumption of the lubricant. This is thought to have caused a decrease in running performance.

Although this level is better than those clearly measured by jitter, etc., it is a problem for the expected high-density magnetic recording, and clearly shows the superiority of this embodiment.

In the above embodiments, polyethylene terephthalate was used as the polymer film, but other materials such as polyphenylene sulfide, porsulfone, polyethersulfone, polyamideimide, etc. may also be used.

Moreover, the above-mentioned film provided with an undercoat layer can also be used, if necessary.

The ferromagnetic metal thin film also includes Co-Ni, Co-
Fe.

Co-Cr, Co-Ce, Co-P, Co
-Pt, Co-W.

Any such as Co-Ni-Pr may be used. It does not depend on the magnetization direction, and may be laminated with an underlayer and a soft magnetic layer, or the magnetic recording layer itself may be multilayered, etc., as appropriate.

The polymer membrane containing fine carbon particles is preferably one that uses a hydrocarbon monomer gas as a starting material, but there are no particular restrictions on the manufacturing method.

It goes without saying that the filler contained in the back coat layer is not limited to carbon black, but may also be mixed with CaCO3+ T 102 or the like as appropriate.

Effects of the Invention As described above, the magnetic recording medium of the present invention has the excellent effect of ensuring sufficient reliability even in a high humidity environment for narrow track recording and reproduction necessary for high-density magnetic recording and reproduction.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a magnetic recording medium according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a conventional magnetic recording medium. 6...Polymer film, 7...Ferromagnetic metal thin film, 8...Back coat layer, 11...
... Polymer film containing carbon fine particles, 12 ... Lubricating film.

Claims (1)

[Claims] A magnetic recording medium comprising a coating layer containing fine carbon particles on one side of a polymer film, and a polymer film containing fine carbon particles and a lubricating film on a thin ferromagnetic metal film on the other side.