JPS61269219A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide a magnetic recording medium having excellent durability in lubricity, runnability and wear resistance by forming a titanium oxide-contg. layer on a thin ferromagnetic metallic film provided on a nonmagnetic substrate and forming a perfluoropolyether-contg. layer on the surface of the titanium oxide-contg. layer. CONSTITUTION:The titanium oxide-contg. layer 3 is formed on the thin ferromagnetic metallic film 2 provided on the nonmagnetic substrate 1 and the perfluoropolyether-contg. layer 4 is provided on the surface of the layer 3. The perfluoropolyether binds strongly to the titanium oxide and therefore the chipping off of the perfluoropolyether by the friction with a magnetic head, etc. is obviated. The magnetic recording medium having the excellent durability in lubricity, runnability and wear resistance is obtd. The strong bond of the compd. to the titanium oxide is estimated to arise from the formation of the bond between the metallic ions and coordinate bond, etc. in the titanium oxide and the consequent chemical adsorption.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high recording density magnetic recording medium used in the information industry and the like.

Conventional technology Conventional r Fe 203 + Co-containing layer F
e 203 s Instead of so-called coated magnetic recording media, in which ferromagnetic powder such as CrO2 is dispersed in an organic binder and coated on a non-magnetic support, plating methods, sputtering methods, vacuum evaporation methods, ion blating methods, etc. A magnetic recording medium in which a ferromagnetic metal thin film is provided on a nonmagnetic support by the method described above is being researched as a magnetic recording medium for high-density recording.

However, the magnetic recording medium using the ferromagnetic metal thin film produced by the method described above has problems with its wear resistance and running properties.

To begin with, a magnetic recording medium is subjected to high-speed relative motion with a magnetic head during the process of recording and reproducing magnetic signals.

At this time, the magnetic recording medium must run smoothly and stably.

Furthermore, wear and damage due to contact with the magnetic head must not occur.

However, the ferromagnetic metal thin film made by the above-mentioned method cannot withstand the harsh conditions of the magnetic recording and reproducing process, and the running becomes unstable due to the friction of the magnetic head, etc., and it cannot be run for a long time. In some cases, output may drop significantly due to wear, breakage, or generation of wear debris. Therefore, it has been proposed to form a protective film colored with perfluoropolyether via a titanium coupling agent on a ferromagnetic metal thin film.

(Japanese Unexamined Patent Publication No. 59-167848) Problems to be Solved by the Invention However, in this case, although the initial lubricity is slightly improved, the lubricity is not durable and the running stability and wear resistance are also poor. I cannot say that it is still sufficient. This is because the bond between the titanium coupling agent and perfluoropolyether is weak, at the level of physical adsorption, and the perfluoropolyether is scraped off by magnetic heads etc. that slide during running. be.

The present invention has been made in view of these points, and an object of the present invention is to provide a magnetic recording medium with excellent lubricity durability, runnability, and abrasion resistance.

Means for Solving the Problem A titanium oxide containing layer is formed on a ferromagnetic metal thin film provided on a nonmagnetic substrate, and a perfluoropolyether containing layer is provided on the surface of the titanium oxide containing layer.

Function Perfluoropolyether binds strongly to titanium oxide. Therefore, the perfluoropolyether is not scraped off by friction with a magnetic head, etc., so a magnetic recording medium with excellent lubrication durability, runnability, and wear resistance can be obtained.

The reason why the above compound strongly binds to titanium oxide is presumed to be because it forms bonds such as coordinate bonds with metal ions in titanium oxide and is chemically adsorbed.

The embodiment diagram is a cross-sectional view of the magnetic recording medium of the present invention. In the figure, 1 is a nonmagnetic substrate, 2 is a ferromagnetic metal thin film, 3 is a titanium oxide-containing layer, and 4 is a perfluoropolyether-containing layer.

As the nonmagnetic substrate 1 that can be used in the magnetic recording medium according to the present invention, well-known materials such as polymer materials such as polyvinyl chloride, cellulose polycarbonate acetate, polyimide, and polyamide, nonmagnetic metal materials, and ceramic materials such as glass and porcelain are used. A film consisting of

There are boards etc.

Further, as the ferromagnetic material forming the ferromagnetic metal thin film 2 that can be used in the magnetic recording medium of the present invention, any known material can be used, such as iron and cobalt.

One or more alloys of nickel or these with other metals such as manganese, chromium, titanium, phosphorus, yttrium,
There are alloys made by combining samarium, bismuth, etc., and oxides of the above metals.

The ferromagnetic metal thin film 2 can be formed on the non-magnetic substrate 1 by any known method such as a vacuum evaporation method, a sputtering method, an ion blasting method, or a plating method.

In the present invention, the key point is to provide the titanium oxide-containing layer 3 on the ferromagnetic metal thin film 2 as described above.

The titanium oxide that can be used in the present invention is TiO.

■　　　　　　■.

Ti OTiOM - TiO3 (M, Ba, P
b, Fe23j 2ff I I M2-Ti205 (M: monovalent metal such as Na)
etc. MI and MH are not single metals, but Pb and F.
e.

It may be a compound such as K and Na. (For example, Pb
! Fe1-, x@Ti○3. NaxKl-!・1102
(1) According to the present invention, the titanium oxide-containing layer can be formed on the ferromagnetic metal thin film 2 by sputtering, vacuum evaporation, or the like.

When forming the titanium oxide-containing layer 3 on the ferromagnetic metal thin film 2 according to the present invention, the film thickness is preferably 60 to 400 layers.

Generally, if the film thickness is 600 mm or more, it is not preferable because the output will decrease due to spacing loss during signal reproduction. Furthermore, if the number of participants is less than 50, pinholes are likely to occur, and a combined effect with perfluoropolyether cannot be expected.

According to the present invention, the perfluoropolyether-containing layer 4 is provided on the titanium oxide-containing layer 3 described above.

Examples of perfluoropolyethers that can be used in the present invention include the following general formulas:); CF3fQ02F
4+i+0CF29. -0CF3. -(A)F(-CF
A hydroxyl group, a carboxyl group, or a phosphoric acid group is present at the molecular terminal of the polyether represented by (CF3)CF20-)2-02F6-(B) or these polyneedle.

Examples include those into which a polar group such as a sulfone group or a salt or ester group thereof is introduced. a in the above general formula,
b and a are integers, and from the viewpoint of lubricity, those in the range of 10 to 60 are preferably used.

However, various other commercially available products can be used as desired.

The perfluoropolyether-containing layer 4 can be formed on the titanium oxide-containing layer 3 by a coating method, a vacuum deposition method, or the like.

When the perfluoropolyether-containing layer 4 is formed on the titanium oxide-containing layer 3 according to the present invention, the film thickness is preferably 60 to 460 mm, and preferably 100 to 300 mm in terms of lubricity. . However, the combined thickness of the titanium oxide-containing layer 3 needs to be less than SOO8. If the number of participants exceeds 600, the output will decrease due to spacing loss during signal reproduction, which is not preferable. Furthermore, if the film thickness of perfluoropolyether is less than 50 mm, the lubricity will be significantly reduced, which is not preferable.

The present invention will be explained below by giving specific examples.

Example 1 A ferromagnetic metal thin film of cobalt (9(1)-chromium (10%)) with a thickness of 1600 mm was formed on a polyimide film substrate with a thickness of 20 μm by vacuum evaporation. A piece with a diameter of 752H was cut out from the formed substrate, and a Ti02 thin film with a thickness of 100 mm was formed on the ferromagnetic metal thin film by sputtering.Next, using a spinner, the following A 1100 pp Freon solution of the compound was coated on top of the Tlo2 thin film layer.

A solution of 2CG was applied at a rotation speed of 50 Orpm, and the rotation speed was subsequently increased to 100 Orpm to dry the solvent.

Sample I Krytox-157FS/M (carboxyl group introduced into perfluoropolyether with structure B) Sample 2 Krytox-143/AC (perfluoropolyether with structure B) Sample 3 Fombl 1n-Z ( Perfluoropolyether with structure A) Still in place of Ti02 in the previous example, 1000 ppm of a titanium coupling agent (Inglobil triinstearoyl titanate) was added on top of the ferromagnetic metal thin film.
) A toluene solution was coated on top of which a 100 ppm Freon solution of the following compound was spin coated as a comparative example. The coating regulations were the same as in the example.

Comparative example 1 Krytox-157FS/M Comparative example 2 K
rytox-143/AC Comparative Example 3 Fomblin
-Z Example 2 In Example 1, a sample was prepared using the following compound instead of TiO2.

Sample 4 P bT zOa Sample 5 BaTiO3 Sample 6 Na 2T tO3 Sample 7 K2TiO3 After vacuum drying Samples 1 to 7, the thickness of the perfluoropolyether-containing layer was measured with an ellipsometer and found to be 100
There were ~120 people.

Samples 1-7. The dynamic friction coefficients of the samples of Comparative Examples 1 to 3 were measured using a dynamic friction coefficient needle (DFPM type, manufactured by Kyowa Kagaku). The head used was a steel ball with a diameter of 31M, and the head load was 1o01. Measurement was made at a head running speed of 1.011j/s. The results are shown in the table.

From the data in the table, it can be seen that the magnetic recording medium of the example according to the present invention has a low initial dynamic friction coefficient as well as a low dynamic friction coefficient even after 200 reciprocations, and is superior to the comparative example in terms of sliding durability.

In addition, when these magnetic recording media were run on a test machine with the same function as a commercially available 70 tsupee disk, the results were 1 to 1.
All samples No. 7 ran stably even after 100 hours, and no wear scratches were observed. On the other hand, the samples of Comparative Examples 1 to 3 ran unstable and sharp abrasion scratches were observed on the magnetic surface.

Note that although the above embodiments have been described with respect to magnetic disks,
The magnetic recording medium of the present invention is a magnetic tape.

It is clear that the present invention can also be applied to magnetic cards and the like.

Effect of the invention The magnetic recording medium of the present invention has smoothness, durability, and runnability.

It has excellent wear resistance and can be maintained for a long period of time.

[Brief explanation of the drawing]

The figure is a sectional view of a magnetic recording medium in an embodiment of the present invention. 1...Nonmagnetic substrate, 2...Ferromagnetic metal thin film, 3...Titanium oxide containing layer, 4...
Perfluoropolyether-containing layer. Name of agent: Patent attorney Toshio Nakao
Spittle L-TanU ξ

Claims (3)

[Claims] (1) A magnetic recording medium in which a titanium oxide-containing layer is formed on a ferromagnetic metal thin film provided on a non-magnetic substrate, and a perfluoropolyether-containing layer is formed on the surface of the titanium oxide-containing layer. (2) The magnetic recording medium according to claim 1, wherein the titanium oxide-containing layer has a thickness of 60 to 400 Å. (3) Titanium oxide is TiO, Ti_2O_3, TiO
_2, M^IITiO_3, M^ I _2O・TiO_2
, M^ I _4TiO_4, M^ I _2Ti_2O_5
The magnetic recording medium according to claim 1, comprising one or any combination of (M^I: monovalent metal, M^II: divalent metal).