JPH0786033A - Thin film and method of forming the same - Google Patents

Abstract

(57) [Summary] [Purpose] Good running performance and excellent antistatic effect.
It is another object of the present invention to provide a magnetic recording medium having less dropout and excellent reproducing characteristics. [Structure] A thin film formed by evaporating particles from a plurality of evaporating streams having different directions on the surface of a support at the same location.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film (in particular, a metal thin film type magnetic recording medium) and a thin film forming method (in particular, a method for producing a metal thin film type magnetic recording medium).

[0002]

BACKGROUND OF THE INVENTION Magnetic recording media such as magnetic tapes are of a coating type in which a magnetic coating in which a magnetic powder or a binder is dispersed in a solvent is coated on a film which is a non-magnetic support.
There is a metal thin film type in which metal magnetic particles are deposited on a film without using a binder.

Among these, the metal thin film type magnetic recording medium is said to be suitable for high-density recording because the magnetic layer does not contain a binder and therefore has a high packing density of the magnetic material. By the way, the metal thin film magnetic recording media currently on sale or under development have the structure shown in FIG. In FIG. 3, 31 is a polyethylene terephthalate (PET) film having a thickness of 2 to 50 μm, and 32 is
For example, the thickness is 1500Å which is constructed by vacuum deposition method.
Is a Co-Ni (80% -20%) alloy magnetic film, 33 is a lubricant film, and 34 is a back coat layer. The back coat layer 34 is prepared by dispersing carbon black having a particle diameter of 10 to 100 nm and a binder resin in a coating material and using a gravure method, a reverse method or a die coating method, and the thickness after drying is 0.4. It is formed by coating so as to have a thickness of up to 1.0 μm.

Here, the role of the back coat layer is as follows. (1) By having conductivity, antistatic is achieved,
Prevents adhesion of dust. (2) Surface stability (coefficient of friction) is improved to obtain running stability. (3) The front magnetic layer and the back magnetic layer are balanced to prevent warpage. Thus, even in the metal thin film type magnetic recording medium, the back coat layer is still a coating type.

By the way, when the back coat layer is first applied and then the magnetic layer is vacuum-deposited, degassing (generated from the solvent of the binder) is generated from the back coat layer in a vacuum system, the degree of vacuum is lowered, and vapor deposition is carried out. It does not work well, the magnetic film cannot be formed well, and a high-performance magnetic recording medium cannot be obtained.
Therefore, after forming the magnetic film in a vacuum, the magnetic film is taken out into the atmosphere and the back coat layer is applied.

However, this method has a problem that in the step of applying the back coat layer, the magnetic layer becomes dirty or dust is attached to increase the dropout.
Further, although the conductivity of carbon black is good, there is also a problem that the conductivity is lowered due to the large amount of binder and the antistatic effect is low.

[0007]

DISCLOSURE OF THE INVENTION An object of the present invention is to have good running performance, and
It has an excellent antistatic effect and little dropout,
A magnetic recording medium having excellent reproduction characteristics is provided.
This object of the present invention is achieved by a thin film characterized in that vaporized particles from a plurality of vaporized streams having different directions are deposited on a support surface at the same location.

Further, vaporized non-magnetic particles from a plurality of vapor streams having different directions are deposited on the non-magnetic support surface at the same location, and the surface roughness of the deposited non-magnetic film (center line average roughness R
a) is 10 to 20 nm, which is achieved by a thin film (magnetic recording medium). Further, vaporized non-magnetic particles from a plurality of vapor streams having different directions are deposited on the non-magnetic support surface at the same location, and the surface roughness (center line average roughness Ra) of the deposited non-magnetic film is 10 to 10. This is achieved by a thin film (magnetic recording medium) having a thickness of 20 nm and a metal magnetic film provided on the surface of the non-magnetic support opposite to the deposited non-magnetic film.

Also, a method of forming a thin film on a support, wherein a thin film material source is irradiated with a plurality of electron beams to generate evaporation flows in a plurality of directions from the thin film material source, and evaporation in a plurality of directions is performed. It is achieved by a thin film forming method characterized in that vaporized particles from a stream are deposited on the same surface of a support. In particular, it is a method of forming a thin film on a support, in which the same thin film material source is irradiated with a plurality of electron beams to generate evaporation streams in a plurality of directions from the same thin film material source. It is achieved by a thin film forming method characterized by depositing evaporated particles from an evaporated stream on a support surface in the same place.

In this thin film forming method, it is preferable that the liquid surface of the thin film material source irradiated with the electron beam is inclined. The material of the magnetic particles forming the metal magnetic film provided on one surface of the support is, for example, Fe,
In addition to metals such as Co and Ni, Co-Ni alloys, Co-P
t alloy, Co-Ni-Pt alloy, Fe-Co alloy, Fe
-Ni alloy, Fe-Co-Ni alloy, Fe-Co-B alloy, Co-Ni-Fe-B alloy, Co-Cr alloy, or those containing a metal such as Al is used.

The material of the particles forming the non-magnetic film provided on the other surface of the support is, for example, Cu-Al-X.
(However, X is one or two or more selected from the group of Mn, Fe, and Ni.) Based alloys, Al-Si based alloys, etc. are used. In addition, metals such as Al, Zn, Sn, Ni and Ag are also used. Cu-Al-X (where X is M
One or two or more selected from the group consisting of n, Fe, and Ni) -based alloy has an Al content of 5 to 5
It is preferably 30 at% and the X content is 5 at% or less. Particularly preferably, the Cu content is 70 to 90.
at%, Al content is 8 to 25 at%, Mn content is 0.5 to 4 at%, Fe content is 0.4 to 5 at%.
And the Ni content is 0.4 to 4 at%, Mn, F
It is preferable that the total content of e and Ni is 1 to 6 at%. Further, the Al content in the Al-Si alloy is 15 to
It is preferable that the Si content is 70 at% and the Si content is 15 to 70 at%.

The relationship between the metal magnetic film and the non-magnetic film (back coat film) provided on the surface of the support is preferably such that the direction of stress caused by the metal magnetic film and the direction of stress caused by the back coat film are the same. . For example, when the stress generated by the metal magnetic film is of the tensile stress type, it is preferable to select the type (metal composition) and forming conditions of the backcoat film so that the stress expressed by the backcoat film is also of the tensile stress type. . Also, when both films are of the tensile stress type, the absolute value of the stress generated by the back coat film is designed to be larger than the stress expressed by the metal magnetic film, whereby the curl rate is 0 to 15%. , Preferably 5-15%,
It is even more preferable to set it to 5 to 10%. Further, when the stress generated by the metal magnetic film is of the compressive stress type, it is preferable to select the type (metal composition) and forming condition of the backcoat film so that the stress expressed by the backcoat film is also of the compressive stress type. . Moreover, when both films are of the compressive stress type, the absolute value of the stress generated by the back coat film is designed to be smaller than the stress expressed by the metal magnetic film, whereby the curl rate is 0 to 15%. , Preferably 5
It is even more preferable to be -15%, more preferably 5-10%.

The support is non-magnetic, and the support is made of polyester such as PET, polyamide, polyimide, polysulfone, polycarbonate, olefin resin such as polypropylene, cellulose resin, or vinyl chloride resin. Polymer materials such as resins, inorganic materials such as glass and ceramics, and metal materials such as aluminum alloys are used.

When a thin film (a non-magnetic film (a back coat film made of a metal film) or a metal magnetic film) is formed as described above, it becomes extremely easy to set the surface roughness of the thin film surface, and moreover, it is desired. Can be set to. In particular, the magnetic recording medium having the back coat film (metal film) provided on the surface opposite to the metal magnetic film as described above has the following characteristics: (1) sufficient conductivity, antistatic property, and dust adhesion; Is prevented. (2) The surface property is improved and running stability can be achieved. (3) Both sides of the support surface can be balanced and warpage can be prevented from occurring. Such features are exhibited.

The back coat film having such characteristics may be formed after the metal magnetic film is formed, first, or simultaneously. When performing the process separately, one thin film should be formed and wound on a roll, and then the roll should be taken out of the vacuum device into the atmosphere and loaded into another vacuum device to form the other thin film. However, there is no problem such as adhesion of dust.

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

[0017]

1 and 2 are schematic views of an apparatus (vacuum vapor deposition apparatus) used for manufacturing a magnetic recording medium according to the present invention. FIG. 1 is an overall explanatory view, and FIG. 2 is an explanatory view of essential parts. Is.
In each figure, 1 is a vacuum container, 2 is a turbo pump, 3 is a rotary pump, 4 is a supply side roll of a support 6, and 5 is a support 6.
Roll on the take-up side, 7 is a cooling can, 8 is a crucible made of MgO, 9a and 9b are electron guns (9b is not shown), 10
Is a shielding plate, and 11 is an oxygen gas introducing pipe.

Then, using such a device, first,
A Co—Ni alloy magnetic film, for example, is formed on the support 6.
That is, after the vacuum container 1 is evacuated to a vacuum degree of about 10 ⁻⁴ to 10 ⁻⁶ Torr, the magnetic metal (80% Co-20% N) in the crucible 8 is heated by electron beam heating of an electron gun.
A metal thin film type magnetic recording medium is manufactured by evaporating i) and depositing a magnetic metal having a thickness of 0.04 to 1 μm, for example, 1500Å on the support 6 such as a PET film. The surface roughness Ra of this Co--Ni alloy magnetic film is
Was 2 nm.

When forming the metal magnetic film, oxygen is supplied from the oxygen gas introduction pipe 11 to the vapor deposition portion and forced oxidation is performed to oxidize the surface layer portion of the metal magnetic film to form a protective layer by the oxide film. Preferably.
The thickness of the protective layer composed of this oxide film is about several tens of liters, and an oxide film of this thickness may be composed of natural oxidation. In some cases, no action is required.

After that, the winding-side roll 5 is taken out, and the winding-side roll 5 is placed on the support portion of the supply-side roll so that the side on which the metal magnetic film is formed abuts on the cooling can 7, and the crucible 8 is backed. Cu-Al-Ni (8
5 at% -10 at% -5 at%) alloy, and after evacuating the inside of the vacuum container 1 to a vacuum degree of about 10 ^-4 to 10 ^-6 Torr, two electron beams from the electron guns 9 a and 9 b By heating, the non-magnetic metal in the crucible 8 is evaporated as shown in FIG. 2, and 0.04 to 1 μm is applied to the other surface of the support 6.
For example, a non-magnetic metal having a thickness of 1700Å is deposited. That is, the crucible 8 having an inner surface formed in a mortar shape is rotated, and the liquid surface of the molten Cu—Al—Ni alloy is tilted by the centrifugal force, so that two electron beams are tilted from the electron guns 9a and 9b at different positions. The surface was irradiated, and the Cu-Al-Ni alloy was operated so that the Cu-Al-Ni alloy was incident from the front and rear oblique directions with respect to the traveling direction of the support and deposited.

In forming the metal non-magnetic film, oxygen is supplied from the oxygen gas introducing pipe 11 to the vapor deposition portion to forcibly oxidize the surface portion of the metal non-magnetic film. The oxygen gas introduction amount from the oxygen gas introduction pipe 11 is 99.
Oxygen with a purity of 998% is at a rate of 25 ml / min. The amount of oxygen introduced can be adjusted by a flow rate control valve (not shown).

Thereafter, fluorine perfluoropolyether (grade: FOMBLIN ZDIAC carboxyl group-modified, manufactured by Nippon Montedison Co., Ltd.) was added to a fluorine-inert liquid (Fluorinert, FC-84, manufactured by Sumitomo 3M Co., Ltd.) so as to be 0.1%. The diluted / dispersed paint is applied to the surface of the metal magnetic film by a die coating method so that the thickness after drying is about 20Å, dried at 70 ° C, and slit into a predetermined width to obtain a magnetic tape. It was

When the back coat layer is formed as described above, the surface roughness (Ra) according to ordinary vacuum deposition is obtained.
Becomes 1 to 2 nm and the friction coefficient becomes as high as 0.6 to 1.0, and running stability deteriorates, while the surface roughness (Ra) can be made rough, for example, 10 to 20 nm. The friction coefficient was 0.1 to 0.4. As a result, the running property is improved, the antistatic effect is excellent, the adhesion of dust can be prevented, and the front and back sides can be balanced.
The hit against the magnetic head was good.

Incidentally, the dropout was reduced by about 30% as compared with the conventional coating type backcoat layer. In addition, the dropout was reduced by about 20% compared to the case where the back coat layer was formed by a simple vacuum deposition method (Ra = 2 nm, friction coefficient was 0.8).

[0025]

According to the present invention, it is possible to obtain a magnetic recording medium which is excellent in running property and antistatic property, has less dropout, and has excellent recording / reproducing characteristics.

[Brief description of drawings]

FIG. 1 is a schematic view of an entire apparatus used for manufacturing a magnetic recording medium according to the present invention.

FIG. 2 is a schematic view of a main part of an apparatus used for manufacturing a magnetic recording medium according to the present invention.

FIG. 3 is a schematic view of a metal thin film type magnetic recording medium.

[Explanation of symbols]

 1 Vacuum Container 6 Support 9a, 9b Electron Gun 10 Shielding Plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Shiga 2606 Akabane, Kai-cho, Haga-gun, Tochigi Prefecture Kao Co., Ltd.

Claims (6)

[Claims] 1. A thin film, characterized in that vaporized particles from a plurality of vaporized streams having different directions are deposited on the surface of a support at the same location. 2. Evaporated non-magnetic particles from a plurality of evaporative streams of different directions are deposited on a non-magnetic support surface at the same location, and the surface roughness of the deposited non-magnetic film (center line average roughness R
2. A) is 10 to 20 nm.
Thin film. 3. Evaporated non-magnetic particles from a plurality of evaporative streams of different directions are deposited on a non-magnetic support surface at the same location, and the surface roughness of the deposited non-magnetic film (centerline average roughness R
2. The thin film according to claim 1, wherein a) is 10 to 20 nm, and a metal magnetic film is provided on the surface of the non-magnetic support opposite to the deposited non-magnetic film. 4. A method of forming a thin film on a support, which comprises irradiating a thin film material source with a plurality of electron beams to generate evaporation flows in a plurality of directions from the thin film material source, and evaporating in the plurality of directions. A method for forming a thin film, characterized in that vaporized particles from a stream are deposited on the surface of a support at the same location. 5. The method of forming a thin film according to claim 4, wherein the same thin film material source is irradiated with a plurality of electron beams to generate evaporation flows in a plurality of directions from the same thin film material source. 6. The thin film forming method according to claim 4, wherein the liquid surface of the thin film material source irradiated with the electron beam is inclined.