JPH07244850A - Method and apparatus for manufacture of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium which has excellent magnetic characteristics and corrosion-resistance efficiently by a method wherein radicals by which the magnetic characteristics are improved are applied to magnetic metal deposited on a supporter. CONSTITUTION:A supporter 1 is loaded in a vacuum chamber 8 and made to run. In this state, Fe 6 in a crucible 5 is melted and evaporated by an electron gun 7 and deposited on the supporter 1. In this state, nitride radicals are applied to the deposited Fe film by a radical irradiating apparatus 10. The applied nitride radicals react with Fe and an FexN ferromagnetic film is formed on the surface of the supporter 1. The irradiating apparatus 10 is composed of a gas introducing tube 11 and an ultraviolet radiation generating lamp 12 wound around the tube 11. Nitride gas is supplied from the base end side of the gas introducing tube 11 and radicals are produced by the ultraviolet radiation applied to the nitride gas en route and the nitrogen radicals are discharged from the tip side of the gas introducing tube 11. The magnetic film formed in this process has excellent corrosion resistance and its film forming speed is high. With this constitution, a magnetic recording medium having excellent corrosion- resistance and magnetic characteristics can be obtained efficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for manufacturing a metal thin film type magnetic recording medium.

[0002]

BACKGROUND OF THE INVENTION In a magnetic recording medium such as a magnetic tape, due to a demand for high density recording, a binder resin is not used as a magnetic layer provided on a non-magnetic support, instead of a coating type using a binder resin. It is well known that a metal thin film type that is not used has been proposed.

That is, there has been proposed a magnetic recording medium having a magnetic layer formed by a wet plating means such as electroless plating, or a dry plating means such as vacuum deposition, sputtering or ion plating. Since the magnetic recording medium of this type has a high packing density of magnetic material, it is suitable for high-density recording. By the way, as a magnetic material forming a magnetic layer in a metal thin film type magnetic recording medium of this type, a magnetic metal such as a Co—Cr alloy or a Co—Ni alloy is used. However, since Co is a rare substance, there are problems of cost and environmental pollution.

On the other hand, in view of the fact that Fe does not have the above-mentioned problems, Fe has begun to attract attention as a magnetic material for a metal thin film type magnetic recording medium. That is, although Fe and Ni can be considered as the non-Co-based metallic magnetic material, it is said that Fe is preferable in view of the magnitude of saturation magnetization. By the way, since Fe is more likely to rust than Co, it is necessary to be chemically stable. From such a point of view, it is proposed that the magnetic film is made of Fe _x N (Japanese Patent Laid-Open Nos. 60-236113 and 63-2372).
No. 19). A magnetic recording medium having a magnetic film made of these Fe-based metal compounds is said to have good magnetic characteristics, excellent corrosion resistance, and excellent high-density recording.

As means for forming the magnetic film of these Fe-based metal compounds, means by ion assist using an ion gun has been proposed. That is, in the process of depositing Fe on the support by the oblique vapor deposition method, a means has been proposed in which nitrogen ions are bombarded toward the deposited metal film by an ion gun. However, such an ion assist method is expensive because the ion gun is expensive, and is not satisfactory in manufacturing efficiency.

[0006]

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a magnetic recording medium which is low in cost, good in manufacturing efficiency, and excellent in magnetic characteristics. The object of the present invention is to evaporate a magnetic metal and deposit the evaporated particles on a non-magnetic support, and to irradiate radicals that are generated by UV irradiation and react with the magnetic metal to improve magnetic properties. And a step of manufacturing the magnetic recording medium.

Further, a container containing the magnetic metal, an evaporation means for evaporating the magnetic metal in the container, and a non-magnetic support for accumulating evaporated particles evaporated by the evaporation means,
The present invention is achieved by an apparatus for manufacturing a magnetic recording medium, comprising: a radical irradiating unit that irradiates radicals that are generated by ultraviolet irradiation and react with the magnetic metal to improve magnetic characteristics.

As the magnetic metal used as the evaporation source material in the present invention, for example, Fe having a purity of 99.95% or more, Fe-Co alloy, Fe-Ni alloy, Fe-Pt are used.
Alloy (however, when adopting a method such as binary vapor deposition, it is sufficient to put Fe and an alloy element such as Ni in each crucible, and it is not always necessary to use an alloy) Preferred examples include high-purity Fe and Fe-based metals containing this as the main component.

As a radical for reacting with a magnetic metal to improve magnetic properties, for example, nitrogen gas (N ₂ ) or a mixed gas of nitrogen and hydrogen (N ₂ +) is used.
H ₂ ), mixed gas of ammonia and hydrogen (NH ₃ +
H ₂ ) or a mixed gas of nitrogen and oxygen (N ₂ + O ₂ ).
Etc. Hereinafter, the present invention will be described in more detail.

FIG. 1 is a schematic view of an apparatus for carrying out the method of manufacturing a magnetic recording medium of the present invention. In the figure, 1 is a non-magnetic support, and this support 1 is polyester such as polyethylene terephthalate (PET), polyamide, polyimide, polysulfone, polycarbonate, olefin resin such as polypropylene, cellulose resin,
Polymer materials such as vinyl chloride resins, inorganic materials such as glass and ceramics, and metal materials such as aluminum alloys are used.

An undercoat layer for improving the adhesion to the magnetic film is provided on the surface of the support 1. That is, in order to improve the adhesion of the magnetic film formed by dry plating by appropriately roughening the surface roughness and further improve the runnability by making the surface roughness of the magnetic recording medium surface moderate, for example, The undercoat layer is formed by providing a coating film containing particles such as SiO ₂ and having a thickness of 0.01 to 0.5 μm.

Reference numeral 2a is a supply side roll, 2b is a winding side roll, and the support 1 is configured to run between them. 3 is a cooling can roll, 4 is a shielding plate, 5 is a crucible, 6 is Fe with a purity of 99.95% or more, 7 is an electron gun,
Reference numeral 8 is a vacuum container, 9 is an oxygen gas supply nozzle that irradiates oxygen along the film deposited on the support 1 guided by the cooling can roll 3, and 10 is a nitrogen radical toward the film deposited on the support 1. It is a radical irradiation device for irradiation.

The radical irradiating device 10 is constructed as shown in FIG. 2, in which an ultraviolet ray generating lamp 12 is wound around a gas introducing tube 11 made of glass which hardly absorbs ultraviolet rays. And gas introduction pipe 1
When the nitrogen gas is supplied from the base end side of No. 1, radicals are efficiently generated by the ultraviolet rays radiated along the way, and the nitrogen radicals are released from the tip end side of the gas introduction pipe 11.

Then, the inside of the vacuum container 8 is evacuated to a predetermined vacuum degree, the support 1 is run, and in this state, the electron gun 7
Then, Fe in the crucible 5 is melted and evaporated, and deposited on the support 1. In this state, the radical irradiation device 10
From this, nitrogen radicals are radiated toward the Fe vapor deposition film, and the radiated nitrogen radicals react with Fe to form a Fe _x N ferromagnetic film on the surface of the support 1.

Further, at this time, if oxygen is irradiated from the oxygen gas supply nozzle 9 toward the vapor deposition (deposition) film, surface oxidation will be performed. In this way, the Fe-based compound ferromagnetic film is formed without using an ion gun. Further, according to this technique, since the ion gun is not necessary, the magnetic recording medium can be manufactured at low cost.

Furthermore, what is interesting is that the coercive force Hc is higher and the saturation magnetic flux density Bs is larger than that when the film is formed using an ion gun. That is, a magnetic material having excellent magnetic properties was obtained. Further, it was also excellent in corrosion resistance. In addition, the film forming rate was also high.

[0017]

【Example】

Example 1 A PET film 1 having a thickness of 10 μm was mounted on an oblique vapor deposition apparatus as shown in FIG. 1, and the PET film 1 was run at a running speed of 5 m / min. The purity of 99.9 contained in the magnesium oxide crucible 5
9% Fe was evaporated by operating the electron gun 7 of 15 kW, and Fe was deposited and deposited on the PET film 1. still,
At this time, the inside of the vacuum container 8 was 2 × 10 ⁻⁵ Torr.

At the time of Fe deposition, nitrogen gas is supplied toward the PET film 1 from the base end side of the gas introducing pipe 11 (30
cc / min), ultraviolet rays were irradiated in the middle of the passage, and nitrogen radicals were irradiated from the tip side of the gas introducing pipe 11. In this way, on the back surface side of the PET film 1 having the Fe _x N ferromagnetic film formed on the front surface at a thickness of 1500 Å, the average particle size is 20 n.
m of carbon black was dispersed in a binder resin of urethane prepolymer and vinyl chloride resin, and a back coat paint was applied by a direct gravure method to a dry thickness of 0.5 μm and dried. .

After this, perfluoropolyether (FO
MBLIN Z DIAC Carboxyl group-modified, manufactured by Nippon Montedison Co., Ltd.) is diluted and dispersed in a fluorine-inert liquid (Fluorinert, FC-77, Sumitomo 3M Co., Ltd.) to a concentration of 0.1% and dried by a die coating method. It is applied to the surface of the metal magnetic film so that the thickness afterwards is about 20 Å, dried at 105 ° C, and slit into a predetermined width,
I got a magnetic tape.

[Embodiment 2] In Embodiment 1, oxygen is supplied toward the vapor deposition film from the oxygen gas supply nozzles 9 to 4 during film formation.
It was sprayed at 0 sccm. [Third Embodiment] In the first embodiment, instead of supplying the nitrogen gas to the gas introducing pipe 11, a mixed gas of ammonia and hydrogen (NH ₃ : H ₂ = 3: 1) is supplied (30 cc / min). In the same manner, a magnetic tape was obtained.

[Example 4] In Example 1, the purity was 9
A magnetic tape was obtained in the same manner except that an Fe-Ni alloy was used instead of 9.99% Fe. [Comparative Example 1] Ion-assisted oblique vapor deposition apparatus with a thickness of 10 μm
m PET film was mounted and the PET film was run at a running speed of 0.8 m / min. And the purity of 99.99 put in the crucible made of magnesium oxide
% Fe was evaporated by operating a 15 kW electron gun.
The inside of the vacuum container at this time was 2 × 10 ⁻⁵ Torr.

At the time of Fe deposition, nitrogen ions are radiated toward the deposited film by an ion gun, and Fe _{x of} 1500 Å is irradiated.
A magnetic tape having an N ferromagnetic film was obtained. [Characteristics] The magnetic characteristics of the magnetic tapes obtained in the above examples were investigated, and the results are shown in Table 1 below.

Table-1 Coercive force (Oe) Saturation magnetic flux density (G) Corrosion resistance ΔBs (%) Example 1 2000 6000 3 Example 2 2400 4800 6 Example 3 2200 5900 3 Example 4 1700 4000 2 Comparative Example 1 1800 5000 5 * Corrosion resistance is the reduction rate of saturation magnetic flux density Bs when immersed in 5% saline for 1 week. This shows that a high-performance magnetic recording medium with excellent magnetic characteristics is more efficient than when an ion gun is used. It turns out that you can get it well.

Further, it can be seen that the obtained magnetic film is also excellent in corrosion resistance. Furthermore, the film forming rate is also high.

[0025]

According to the present invention, a high-performance magnetic recording medium having excellent magnetic characteristics and corrosion resistance can be efficiently obtained.

[Brief description of drawings]

FIG. 1 is a schematic view of a magnetic recording medium manufacturing apparatus of the present invention.

FIG. 2 is a schematic view of a main part of a magnetic recording medium manufacturing apparatus of the present invention.

[Explanation of symbols]

 1 Support 2a Supply Side Roll 2b Winding Side Roll 3 Cooling Can Roll 4 Shielding Plate 5 Crucible 6 Fe 7 Electron Gun with Purity of 99.95% or More 8 Vacuum Container 9 Oxygen Gas Supply Nozzle 10 Radical Irradiator 11 Gas Introducing Tube 12 UV lamp

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shigemi Wakabayashi Inventor Shigemi Wakabayashi 2606 Akabane, Kaiga-cho, Haga-gun, Tochigi Kao Co., Ltd.Institute of Information Science (72) Inventor Akira Shiga 2606 Akabane, Kaiga-cho, Haga-gun, Tochigi Kao Company Information Science Laboratory

Claims (2)

[Claims] 1. A step of evaporating a magnetic metal and depositing the evaporated particles on a non-magnetic support, and a step of irradiating with radicals which are generated by irradiation of ultraviolet rays and react with the magnetic metal to improve magnetic properties. A method of manufacturing a magnetic recording medium, comprising: 2. A container containing a magnetic metal, an evaporation means for evaporating the magnetic metal in the container, a non-magnetic support for accumulating evaporative particles evaporated by the evaporation means, and a non-magnetic support generated by ultraviolet irradiation, An apparatus for producing a magnetic recording medium, comprising: a radical irradiating unit that irradiates a radical that reacts with a magnetic metal to improve magnetic characteristics.