JPS6334721A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide a recording medium having an excellent electromagnetic conversion characteristic by disposing a diagonally vapor deposited film at <=70 deg. max. incident angle onto a high-polymer film disposed with granular projections. CONSTITUTION:This recording medium is formed by disposing the diagonally vapor deposited film 8 at <=70 deg. max. incident angle onto the high-polymer film 6 disposed with the granular projections. Since an effective contact area is thereby decreased, the durability of the magnetic recording layer itself is improved. Large stress is exerted to the projection part but the shadowing effect by the projection part is weakened, the aticking strength is increased and the magnetic uniformity is improved by confining the incident angle to <=70 deg.. Modulation noise is, therefore, improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium suitable for high-density magnetic recording.

Conventional technology Recent advances in recording technology have significantly improved the recording density per unit area, and the practical use of magnetic recording media such as vapor-deposited tapes whose magnetic recording layer is a ferromagnetic metal thin film with an extremely smooth surface is rapidly increasing. It is becoming desired. 3 Therefore, there is a growing recognition that future increases in density will be premised on realistic solutions to tribology issues related to understanding the friction, wear, etc. that occur when magnetic heads and magnetic recording media slide. Academic journal, VOL, 40. A6 (1986) 472 pages].

FIG. 2 is an enlarged sectional view of a conventional magnetic recording medium. 1 is a polyester film, a non-magnetic substrate made of AA gold alloy, 2 is a magnetic recording layer such as a Co-Ni-0 obliquely deposited film or a Co-Cr perpendicular magnetization film, 3 is a top coat layer, I is a protective layer, and 6 is a lubricant. It is a 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;
Examples of sputtering using a polymer compound having an imide group as disclosed in Japanese Patent Application Laid-Open No. 7-116771 using a polymer compound as a target, carbon, BN, M o S
Examples of thinning films such as S 2 and S io 2 by sputtering or vapor deposition, and examples of using a diamond-like hard carbon film (materials from the 46th research meeting of the Japanese Society of Applied Magnetics) are known.

In addition, as a layer for lubricating purposes, fatty acids, fatty acid amides, etc. are deposited by vapor deposition, wet coating, etc. (Example 1)
6-30609) have been attempted.

However, the above examples are based on wear resistance and running properties.

Since the anti-corrosion effect cannot be fully satisfied, the idea of laminating layers 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 5t-N-○ thin film
Publication No.) etc.

Problems to be Solved by the Invention However, with the above configuration, the wear resistance, corrosion resistance, and runnability of the magnetic recording layer itself are insufficient, so the thickness of the top coat layer consisting of the protective layer and the lubricating layer is shortened due to spacing loss. Since the size has to be such that the wavelength output is reduced, improving the durability and reliability results in deterioration of the electromagnetic conversion characteristics, which has been desired to be improved. The present invention was made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a magnetic recording medium having excellent electromagnetic conversion characteristics by improving the durability of the magnetic recording layer itself and reducing noise.

Means for Solving the Problems In order to solve the above problems, the magnetic recording medium of the present invention comprises:
The maximum incident angle is 70° on a polymer film with granular protrusions.
A diagonally evaporated film with a thickness of less than

Function: Due to the above-described structure of the magnetic recording medium of the present invention, the effective contact area is reduced, so that the durability of the magnetic recording layer itself is improved. Furthermore, although large stress is applied to the protrusions, by setting the angle of incidence to 70 degrees or less, the shadowing effect of the protrusions is weakened, the adhesion strength is increased, and magnetic uniformity is improved. Modulation noise will be improved.

EXAMPLES Hereinafter, examples of the present invention will be explained in detail 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 the same figure, 6 has a thickness of 10μ
The surface roughness of a polymer film such as a polyethylene terephthalate film (Ra) measured using a stylus roughness meter is 0.003 μm. 7 as fine particles, S i O
2 (average particle size: 200 particles) with an average density of 5 x 109 [pieces/
crti), 8 is a polyester resin undercoat layer containing Co-Ni (Cocoa) in an oxygen atmosphere [oxygen partial pressure 2 x 10-4 (Torr)] of 0.9 to 1.2
Diagonal deposition was performed at a deposition rate of 5 (μ/58c). As the deposition conditions, the deposition rate and the incident angle range were selected as parameters.

The film thickness was kept constant at 15 μm. On the ferromagnetic metal thin film 8, a plasma-polymerized film 9 of rocyclobutane with a thickness of 60 mm is placed, and on top of that is a vacuum-deposited film 1 of stearic acid.
40 people were placed on the magnetic tape, and its durability and noise were compared. Durability was compared based on the still time until noise was generated at 20°C2o%RH, representing the still property since the wear property and frictional resistance of the magnetic recording layer can be evaluated in a short period of time. The noise is standard for 8mm video.
2 (stop) modulation noise was compared relative to each other. The tension during stilling was kept constant at 16 knots. The conditions and evaluation results are summarized in the table.

St5 When the 8-Ryu type video was modified using the above-mentioned medium and the center frequency was set to 0.6 (μm), the improvement in noise was even more noticeable as a difference.

In addition, in order to improve the comparative example to a still time of about 60 minutes, it is necessary to increase the plasma polymerized film to 150 and the stearic acid film to 120, but in this way the high frequency output will be 2
．． The value of the product of the present invention is clear from the fact that it decreased by 5 (dB).

In the above examples, polyethylene terephthalate film was used as the polymer film, but other materials such as polyethylene naphthalate, polyphenylene sulfide, polyimide,
Polyamideimide or the like may also be used.

The fine particles are placed in a SiC2 pond with CaCo3. T t O2
, Fe3O4° polyester spheres, etc., or combinations with earthworm-like protuberances.

The material for the magnetic recording layer is Co in addition to Co-Ni.

Co-Fe, Fe-Ag, Co-Cr, Co
-Mg, Co-Mo.

Co-Ni-P, Co-Ni-Ru, Co-N
f-Pr.

Any of Co-Nt-Au, Co-Ni-Pt, etc. may be used.

The protective layer and lubricating layer may be optimized as appropriate. Note that even when the magnetic recording layer has a multilayer structure, the same effects can be obtained as long as each layer satisfies the requirements of the present invention.

Effects of the Invention As described above, according to the present invention, the durability of the magnetic recording layer itself is improved, the noise is also improved, and a magnetic recording medium capable of being used for high-density magnetic recording can be provided. This is something that can be obtained.

[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...9 layers of undercoat, 8
... Ferromagnetic metal thin film, 9...-protective film, 10... lubricating layer.

Claims (1)

[Claims] The maximum incident angle is 70° on a polymer film with granular protrusions.
1. A magnetic recording medium comprising a diagonally deposited film having a thickness of less than 100 degrees.