JP2718960B2 - Recording medium lubricant and recording medium - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium lubricant applied to the information industry and the like.

2. Description of the Related Art As a recording medium, development of a metal thin film type recording medium in which a recording layer is formed directly on a substrate by a plating method, a sputtering method, a vacuum evaporation method, an ion plating method, or the like instead of a conventional coating type is being actively developed. .

In the above-mentioned metal thin-film type medium, when recording and reproducing a signal, friction and wear occur due to contact with a head and the like, and wear powder and damage are generated. For this reason, various improvements such as improvement of friction resistance and wear resistance have been made by treating the recording layer itself or its surface. For example, a higher fatty acid, a fluorine-based polymer or the like is used alone or a surface treating agent is laminated on the recording layer (JP-A-59-172159). However, the lubricating layer cannot be so thick because of spacing loss. Therefore, although there is a certain improvement in the running property, there are insufficient points such as a phenomenon such as peeling or deterioration over time.

Problem to be Solved by the Invention The present invention has improved friction and wear resistance by increasing the bonding force between the recording layer and the lubricating layer and the bonding force between the lubricating layer molecules, and by increasing the density of the lubricating layer molecules. It is intended to provide a recording medium.

Means for Solving the Problems A recording medium lubricant comprising a three-branched alkylsilane shown below.

(R is a straight-chain alkyl group having 16 to 22 carbon atoms, and R _{2 to} R ₄ are each a halogen, an alkoxy group, an acetoxy group or a hydroxy group.) Action The three-branched alkylsilane is strongly bonded to the recording layer. The two branched alkyl chains increase the surface density of the membrane.

In the three-branched alkylsilane, the Si portions of the alkylsilane are arranged near the recording layer surface, and the alkyl chains are arranged far away from the recording layer surface. The thus-formed three-branched alkylsilane film forms a three-branched alkylsilane film in which the Si portion forms a covalent bond with the recording layer surface and the density of alkyl chains is improved on the recording layer surface.

On the other hand, when a material in which three alkyl chains that are not branched to a silicon atom are connected is used, the density of the alkyl chains on the surface of the recording layer is improved, but the number of functional groups is reduced to one. May be too small to be hidden by chains in the whole molecule. Therefore, the chance of the functional group being oriented or bonded to the substrate side is reduced, and the lubricating layer is easily peeled off.

On the other hand, the three-branched alkylsilane can easily realize the dense packing of the alkyl chain, so that the film density is remarkably improved, and there are three functional groups having a reaction opportunity with the recording layer surface. Therefore, it is easy to orient to the surface,
Also the chances of joining increase. As a result, the shear stress of the lubricating layer increases, the performance with respect to the number of repetitions is improved, and the effect of preventing direct contact between slides is extremely large.

Embodiment FIG. 1 is a sectional view of a recording medium according to the present invention. In the figure 1
Is a substrate, 2 is a recording layer, and 3 is a lubricating layer containing a three-branched alkylsilane.

Examples of the substrate 1 that can be used for the recording medium of the present invention include polymer materials such as polyamide, polyimide, polysulfone, polycarbonate, polypropylene, polyethylene, polyethylene terephthalate, cellulose acetate, and polyvinyl chloride, and non-magnetic metal materials. , Glass, ceramics such as porcelain, and other known materials such as films and plates.

The magnetic material forming the recording layer 2 includes Fe, Co,
At least one or more metals selected from Ni, or alloys of these with Mn, Cr, Ti, P, Y, Sm, Bi, etc., or oxides thereof, among which at least two metals selected from Co, Cr, Ni Recording layers composed of more than one kind of elements are preferable because of having high magnetic anisotropy energy and corrosion resistance, and these are vacuum deposition method, sputtering method,
It can be formed by a method such as an ion plating method and a plating method. Needless to say, the recording layer 2 described in the present invention is not limited to a composition other than the above.

In the present invention, the three-branched alkylsilane used for the lubricating layer can be represented by the following general formula.

R is a linear alkyl group having 16 to 22 carbon atoms, and R _{2 to} R ₄ are each a halogen, an alkoxy group, an acetoxy group or a hydroxy group. γ- [N- [tris (heptadecyloxymethyl)] methylsuccinyl] propyltriethoxysilane, γ- [N- [tris (octadecyloxymethyl)] methylsuccinyl] propyltriethoxysilane and the like are examples. Needless to say, the tribranched alkylsilane used in the lubricating layer described in the present invention is not limited to the above.

The three-branched alkylsilane is firmly bonded to the recording layer, and the three branched alkyl chains increase the surface density of the film.

In the three-branched alkylsilane, the Si portions of the alkylsilane are arranged near the recording layer surface, and the alkyl chains are arranged far away from the recording layer surface. This orientation can be easily realized by a three-branched alkylsilane formed by a Langmuir-Blodgett method or an adsorption method. The thus-formed three-branched alkylsilane film forms a three-branched alkylsilane film in which the Si portion forms a covalent bond with the recording layer surface and the density of alkyl chains is improved on the recording layer surface.

In addition, the three-branched alkyl silane can easily realize the closest packing of the alkyl chain, so that the film density is dramatically improved.
As a result, the shear stress of the lubricating layer increases, the performance with respect to the number of repetitions is improved, and the effect of preventing direct contact between slides is extremely large. Also in this case, the coverage of the three-branched alkylsilane formed by the Langmuir-Blodgett method or the adsorption method is more likely to be improved.

Therefore, the LB film of the three-branched alkylsilane has a sufficient effect even with a monomolecular layer, and the three-branched alkylsilane having an alkyl group having 16 to 22 carbon atoms easily forms the LB film and has a large effect. . Among them, γ- [N- [tris (heptadecyloxymethyl)] methylsuccinylamino] propyltriethoxysilane and γ- [N- [tris (octadecyloxymethyl)] methylsuccinylamino] propyltriethoxysilane are LB films. The effect is great because it is easy to handle and excellent in film formation.

By forming the lubricating layer described above on the recording layer, a recording medium having excellent running properties can be obtained. From the viewpoint of signal recording and reproduction, the thinner the better, the better. Also,
The upper limit of the thickness is desirably 500 A or less as long as the recording output does not deteriorate due to the spacing loss.

 Hereinafter, examples will be described in detail.

Example 1 γ- [N- [tris (heptadecyloxymethyl)]
One layer of methylsuccinylamino] propyltriethoxysilane (3C) was deposited on a Co-Cr magnetic metal ingot by the Langmuir-Blodgett (LB) method under the conditions shown in Table 1. After forming the film, it was dried by heating at 80 ° C. for 30 minutes. For reference, the well-known stearic acid (S
t).

In order to examine the running properties of these samples, a friction element 6RSUJ2,
The test was performed under the conditions of a load (W) of 10 gf and a running speed (v) of 0.5 mm / s.

The untreated recording medium on which no lubricating layer was formed had a coefficient of friction (μκ) as large as 0.35 from the initial stage, and further increased to 0.85 after 50 passes, showing significant wear. On the other hand, in St, the initial μκ was certainly as small as 0.2 and the lubricity was improved. However, when the 50pass run was repeated, μκ was 0.35
And it was as if it showed the separation of St. On the other hand, the recording medium having a lubricating layer formed of γ- [N- [tris (heptadecyloxymethyl)] methylsuccinylamino] propyltriethoxysilane has a μκ of 0.2, which is not much different from St. Also, during repeated running, μκ did not change and no abrasion was observed. As described above, when the silane-based compound having one branched alkyl group and two alkoxy groups such as three ethoxy groups is formed on the recording layer, the lubricating layer becomes the recording layer. This example shows that a recording medium having high durability and excellent running properties can be obtained because of a strong bonding force with the resin and a small peeling.

Example 2 Next, one layer was formed using a three-branched alkylsilane where the alkyl group was hexadecyl (C16), eicosyl (C20), or docosyl (C22), and a circuit was obtained by adding a contact electric measurement method to a friction tester. The wear resistance was examined. Test conditions are 3RSUJ2, w
= 5 gf, v = 1.0 mm / s. At this time, comparison was made with the number of runs (pass) until the substrate was directly contacted, and the surface was observed. The results are shown in Table 2. In addition, as in the first embodiment,
Compared to St.

The wear resistance of the silane compound was improved about 15 to 20 times as compared with St. In the case of St, a deep flaw was observed at the center of the running, whereas the silane-based compound had a flat flaw on the entire running part and the wear was slight. It can be seen that the peeling from the substrate is small and the wear resistance is improved due to the strengthening of the bonding force against repeated sliding. From the above, when a silane compound is used, as shown in this example, a lubricating film having improved wear resistance is obtained, and the effect is effectively exerted on an alkyl chain having 16 to 22 carbon atoms. You can see that there is.

EFFECT OF THE INVENTION By using the recording medium lubricant of the present invention, a recording medium having excellent durability can be realized by being firmly bonded to the recording layer and having low abrasion having an alkyl group.

[Brief description of the drawings]

FIG. 1 is a sectional view of a recording medium according to an embodiment of the present invention. 1 ... substrate, 2 ... recording layer, 3 ... lubrication layer.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-203239 (JP, A)

Claims (3)

(57) [Claims] 1. A recording medium lubricant comprising a three-branched alkylsilane shown below. (R is a linear alkyl group having 16 to 22 carbon atoms, and R _{2 to} R ₄ are each a halogen, an alkoxy group, an acetoxy group or a hydroxy group) 2. The lubricant according to claim 1, wherein the three-branched alkylsilane is γ- [N- [tris (heptadecyloxymethyl)] methylsuccinylamino] propyltriethoxysilane. . 3. A recording medium characterized in that the lubricating layer made of the recording medium lubricant according to claim 1 is formed as a monomolecular layer.