JPH0789413B2 - Magnetic recording medium - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a magnetic recording medium. More specifically, the present invention relates to a magnetic recording medium such as a magnetic disk, a magnetic drum, a magnetic tape, or a magnetic guard.

[Background of the Invention]

Generally, a magnetic recording medium has a magnetic layer formed on various substrates, and the surface of the magnetic layer is rubbed by a magnetic head or the like during recording and reproduction. A major problem is the deterioration of performance due to wear of the magnetic layer that occurs during friction. For example, in a magnetic disk device, the head is in a floating state due to the levitation force of an air film generated on the surface of the rotating disk during a steady operation. However, at the time of starting or stopping the rotation, the flying force is lost, so that the head and the disk come into contact sliding state. In order to reduce the wear of the medium at the time of such contact and not to impair the floating characteristics of the head, a lubricating layer firmly bonded to the medium is required. A surface treatment layer is provided on the magnetic recording layer,
Prisoners who showed that they could improve the adherence of the lubricant,
There are JP-A-59-203240 and JP-A-57-164430.

[Object of the Invention]

An object of the present invention is to provide a magnetic recording medium having a magnetic layer with good wear resistance and excellent durability.

[Outline of Invention]

It is generally known that a lubricant is apt to adhere to an object to be rubbed, and that it is easily sheared in the friction direction to effectively work as a lubricant and to copy wear resistance. Although the use of conventional higher fatty acids and their derivatives or substances such as silicone oil as a lubricant for magnetic recording media has been found to improve wear resistance to some extent, it has not been fully satisfactory.

The magnetic recording medium of the present invention has a surface treatment agent bonded to a magnetic layer via nitrene generated by decomposition of an azide group,
The lubricating substance layer is provided on the surface treatment layer. According to the present invention, a surface treating agent having a molecular structure similar to that of the above-mentioned lubricant is bonded to the surface of the magnetic layer via nitrene, and a magnetic recording medium having excellent sliding resistance can be obtained.

The present invention will be specifically described below. The substance used as the surface treatment agent is selected from compounds having a basic skeleton of alkane and ether and having at least one azide group. The above alkane and ether are not limited to linear ones, but may be branched ones. The basic skeleton preferably has 7 to 30 carbon atoms.

Further, a functional group such as an unsaturated bond or a bud aromatic ring may be introduced near the azido group.

As a method of applying these to a magnetic recording medium, for example, they are attached directly on a magnetic disk or by a wipe method or the like. Then, the surface treatment agent is decomposed by its azide group by irradiation with ultraviolet light or by heating to generate nitrene and is bonded to the surface of the magnetic layer.

The lubricating substance provided on the surface-treated layer is selected from saturated and unsaturated fatty acids or their esters, metal salts, derivatives such as amides, alcohols, polyethers, paraffins and silicone oils. Moreover, it does not matter even if they are mixed.

Examples of the fatty acid residue of the saturated and unsaturated fatty acids and their derivatives include alkyl, alkenyl and alkadienyl having 11 to 22 carbon atoms.

Examples of alcohols include monohydric or polyhydric alcohols having 11 to 26 carbon atoms.

Examples of the polyethers include polymers represented by the following general formula.

Examples of the silicone oil include dialkyl polysiloxane, diphenyl polysiloxy and the like.

The thickness of the surface-treated layer is preferably in the range of 5 to 500Å, more preferably 20 to 25Å. The thickness of the lubricating material should be in the range of 20 to 500Å.
More preferably, it is in the range of 0 to 25Å.

The combined thickness of the surface treatment layer and the lubricating substance layer is
From the viewpoint of uniformity and strength, it is preferably 30 Å or more,
From the viewpoint of reproduction output loss due to spacing between head and medium, it is desirable to be 500 Å or less.

The applicable magnetic recording medium has a magnetic layer of Co--Cr alloy, C
Metal magnetic film such as o-Ni alloy, Co-Fe alloy, Co-P alloy,
Γ-Fe ₂ O ₃ , Co-containing γ-Fe ₂ O ₃ , Fe ₂ O ₄ , Co-containing F in the magnetic layer
Examples include oxide magnetic powders such as e ₂ Co ₄ and CrO ₂ and metal magnetic powders such as Fe, Co, Ni and their alloys. Further, the above-mentioned one having a protective film on the magnetic recording film is also applicable.

Example of Invention

 The present invention will be described in detail below with reference to examples.

Examples 1 to 6 As magnetic recording media, coating type magnetic disks having a diameter of 5 inches prepared by dispersing magnetic powder (γ-Fe ₂ O ₃ ) in a binder made of epoxy, phenol and polyvinyl butyral resin are shown in Table 1. The surface treatment agent described above was applied to a predetermined film thickness and heated at 50 to 60 ° C. for about 30 minutes. The lubricant was sprayed in the form of a Freon solution, and then the excess lubricant was wiped off with a gauze tape while rotating the magnetic disk until the lubricant had a predetermined film thickness. The film thickness of the surface treatment agent and the lubricant was measured by FT-IR.

The sliding strength was measured using an α-alumina slider (with a radius of curvature of 3
The durability was evaluated by repeatedly sliding at a sliding speed of 10 m / sec using a 0 mm spherical slider) and measuring the number of times until scratches were generated on the surface of the magnetic recording medium. The same effect was obtained when exposed with a 600 Watt Xe-Hg lamp instead of the heat treatment.

Comparative Examples 1 to 6 Samples having a predetermined lubricating film thickness were prepared in accordance with the methods shown in Examples 1 to 6 below without applying the surface treatment agent and the treatment, and the samples were rubbed by the sliding test method described above. The dynamic strength was measured.

Examples 7 and 8 As a magnetic recording medium, by RF sputter method in Ar gas
A magnetic disk having a Co—Cr magnetic metal film having a thickness of 0.3 μm formed on a glass substrate was prepared and subjected to surface treatment and application of a lubricant by the methods of Examples 1 to 6 to obtain a sample.

The sliding strength was measured by the sliding test method described above.

Comparative Examples 7 and 8 Lubricants were applied to the surfaces of Co-Cr magnetic media prepared by the same method as described in Examples 7 and 8 in the same manner as in Comparative Examples 1 to 6 to prepare samples.

The sliding strength was measured by the same method as described above.

[Advantages of the Invention] According to the present invention, when the surface treatment layer is provided according to the present invention, the sliding strength is improved by 1.5 to 2.5 times as compared with the case where the surface treatment layer is not provided.

Claims (5)

[Claims] 1. A magnetic recording film, a surface treatment layer having nitrene which is a decomposition product of azide provided on the magnetic recording film, and a lubricating substance layer provided on the surface treatment layer. And a magnetic recording medium. 2. The magnetic material according to claim 1, wherein the surface-treated layer is a decomposition product of a compound having an alkyl chain or a polyether chain as a basic skeleton and having at least one azide group. recoding media. 3. The magnetic recording medium according to claim 1, wherein the lubricating substance layer is selected from saturated and unsaturated fatty acids and their derivatives, paraffin polyethers, alcohols and silicone oils. . 4. The magnetic recording medium according to claim 1, wherein the surface treatment layer has a film thickness of 5 to 500 Å. 5. The magnetic recording medium according to claim 1, wherein the film thickness of the lubricating substance layer is 20 to 500Å.