JPS6126929A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To maintain stable output by exposing more than half the surface of the pulverous inorg. particles fixed to a substrate and forming a magnetic layer on such substrate surface so that the breakdown of the coating by the high-speed sliding contact with an alloy magnetic head is prevented when the particle surfaces are coated with a resin film. CONSTITUTION:The coating liquid prepd. by dispersing the pulverous inorg. particles of Al2O3, SiO2, CaCO3, BaSO4, etc. in a 50-1,000Angstrom range into an epoxy resin soln. is coated on the high-polymer substrate 6 and is dried to fix the particles 7 onto the substrate. The resin sticking to the surface of the particles 7 is etched away from more than half the surface of the particles 7 by executing a glow discharge treatment, etc. under about 0.1 Torr with introduction of gaseous CF4. A Co-Ni alloy or the like is then deposited by evaporation in an oxygen atm. to form the magnetic layer 9 having projections 10 over the entire surface including the resin layer 8 and the particles 7. The magnetic recording medium which obviates the exfoliation, etc. of the magnetic layer, is hardly damaged by the alloy magnetic head, maintains a good still characteristic even at and under a high temp. and high humidity, has the stable output and is suitable for high- density recording is thus obtd.

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.

Structure of conventional examples and their problems In recent years, progress in increasing the density of magnetic recording has been remarkable, and we are trying to further improve the recording density with so-called coated magnetic recording media, in which fine ferromagnetic particles are coated and fixed with a binder. Therefore, it is strongly desired to put a so-called ferromagnetic metal thin film type magnetic recording medium into practical use.

In particular, perpendicular recording media, in which the demagnetization effect becomes weaker as the wavelength becomes shorter, are attracting attention as being able to achieve recording densities approaching that of optical recording.

In order to reduce spacing loss at short wavelengths, the surfaces of both perpendicular and longitudinal recording media are becoming increasingly smooth.

Therefore, in the method of recording and reproducing by direct contact with the magnetic head, even if a protective layer is placed on the ferromagnetic metal thin film, scratches cannot be prevented, making it difficult to put it into practical use. In order to measure this, it has been proposed to make the surface particulate, with some success in reducing spacing loss, improving runnability, and improving abrasion resistance.

However, even with such a configuration, satisfactory characteristics may not be obtained for alloy-based magnetic heads, and problems remain especially when used in high temperature and high humidity environments, and improvements are desired. It is rare.

OBJECTS OF THE INVENTION The present invention was made in view of the above circumstances, and an object of the present invention is to improve the abrasion resistance during high-speed sliding contact with an alloy magnetic head.

Structure of the Invention The magnetic recording medium of the present invention is characterized in that a magnetic layer is disposed on a substrate having a shape in which 172 or more surfaces of fine particles fixed on the substrate are inorganic. It has improved abrasion resistance.

Description of examples - Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 1 is an enlarged schematic diagram of a conventional magnetic recording medium.

A magnetic layer 4 is placed on fine particles 3 fixed on a substrate 1 with a resin 2.
It is explained that the protrusions 6 having fine particles 3 as nuclei reduce effective contact with a magnetic head (not shown) during high-speed sliding contact and improve durability. However, as mentioned earlier, when the magnetic head is made of sendust alloy or amorphous alloy, lubricant (not shown)
Even if improved, the abrasion resistance is weak under high temperature and high humidity.

The present invention significantly solves the above-mentioned problem in the method of fixing the fine particles 3! This is the result of experimentally determining the relationship between the two.

In other words, even if an inorganic material is used for the fine particles, when fixed with silk resin, the surface of the fine particles will be covered with a resin film.
It was speculated that the protrusion could not withstand the stress concentrated at this interface and would break.

Based on that conclusion, the configuration shown in Figure 2 was obtained.

In Figure 2, 6 is a polymer substrate, 7 is an inorganic fine particle, 8 is a resin,
9 is a magnetic layer, and 10 is a protrusion.

It is important that 1/2 or more of the surface of the inorganic fine particles 70 is not coated with resin.

The reason why 1/2 is sufficient is because whether in oblique or vertical evaporation, the range in which the vapor flow is expected rarely exceeds 1/2, and even if it exists, it can be ignored.

The polymer substrate used in the present invention includes polyesters such as polyethylene terephthalate and polytetramethylene terephthalate, polyolefins such as polypropylene,
Cellulose diacetate.

Cellulose derivatives such as nitrocellulose, holamide,
The magnetic recording layer is made of polyimide or the like, and the magnetic recording layer is made of Co or C.

-Fe, Co-Ni, Go-Or, Co-0
, Co-P, Co-V.

Co-Mg, Co-Mn, Co-Mo, Co-Ti, C
o-8t.

Co-5m, C□-3n, Co-W, Co-Zn, Co
-Zr, Fe-Ag, F, e-Cu, Co-Ni
Of course, it is also possible to use a soft magnetic layer or an underlayer as an auxiliary material, such as -0, Co'-Ni-Zn-P, etc., regardless of the axis of easy magnetization.

Inorganic fine particles that can be used in the present invention are A1203
z S t○2, T 102. MgO, ZnO, C
aCo3゜B a S OCa S O4 etc. with 608 to 1000 people, preferably T structure 1008 to 400, and the fixing resin can be any one such as epoxy, polyester, vinyl chloride, acetic acid, cellulose polyimide, etc. Irukkoto can be used for.

Etching is the surest way to reduce the area covered with resin to 1/2 or less.

An example will be described in more detail below.

(Example) After dispersing and fixing various fine particles with polyester resin on a polyethylene terephthalate film with a thickness of 11 μm, C
Introduce F4 gas and maintain at 1 Torr, '1.5
Co-Ni (Ni, 17
%) film was formed to a thickness of 0.15 μm in oxygen at a minimum incident angle of 22 degrees by a continuous incident angle change vapor deposition method, and stearic acid was coated on the surface in an amount of 30 μm thick, dried, and slit into 8-width pieces to form a magnetic film. Got the tape.

The still life of each magnetic head was investigated. The playback output is 3d from the initial value of the signal with a recording wavelength of 0.66μm.
Evaluation was made based on the time taken for B to decrease.

The environmental conditions were the strictest, 46° C., 96% RH constant, and the tension) B3og constant.

The constituent requirements of the tape and the results obtained are summarized in a table. The comparative example was made into a tape without being etched.

As is clear from the margin table below, the still life of the product of the present invention is better than that of the alloy head, and the reproduction output can be stably maintained for a long time not only with ferrite heads but also under high temperature and high humidity.
It can be seen that the abrasion resistance has been significantly improved.

It has been confirmed that the present invention is also effective in forms other than magnetic tapes, and is equally effective in other materials as described above.

Effects of the Invention In the present invention, by composing the surface of the fine particles fixed on the substrate with an inorganic material, the abrasion resistance can be greatly improved even for alloy heads, and it is stable in a still state for a long time even under high temperature and high humidity. This device is capable of reproducing high-density output and can greatly contribute to the practical application of high-density recording.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a conventional magnetic recording medium, and FIG. 2 is an enlarged sectional view of a magnetic recording medium of the present invention. 6...Polymer substrate, 7...Inorganic fine particles,
8...Resin, 9...Magnetic layer, 1o...
protrusion. Figure 1 Figure 2

Claims (1)

[Claims] A magnetic recording medium characterized in that a magnetic layer is disposed on a substrate having a shape in which 1/2 or more of the surface of fine particles fixed on the substrate is inorganic.