JP2843252B2 - Method and apparatus for manufacturing magnetic recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a magnetic recording medium and a magnetic recording medium using the same.

[0002]

2. Description of the Related Art A magnetic recording medium, for example, a magnetic tape includes:
A conventional coating tape in which a magnetic paint in which magnetic powder is dispersed in a binder is applied on a film as a non-magnetic support, and a conventional coating tape in which a metal is evaporated in a vacuum on a film without a binder. There is a mold tape.

[0003] Evaporated tapes are said to be promising for high-density recording because the magnetic layer does not contain a binder so that the density of the magnetic material can be increased.

[0004] The main structure of a vapor deposition type tape which is currently sold or developed is as shown in FIG. the film
51 is made of PET (polyethylene terephthalate), polyimide, aramid or the like. 2-50μm thickness
It is used in various ways.

The magnetic layer 52 is formed by depositing a Co-Ni alloy (80% -20%) with a thickness of 1500 ° on the film 51 by using a vacuum evaporation method. Incidentally, an undercoat layer may be interposed between the film 51 and the magnetic layer 52 in order to improve the binding property and the like. If necessary, a protective layer may be provided between the magnetic layer 52 and the top coat layer 53 in some cases.

The top coat layer 53 protects the magnetic layer 52,
In addition, it is coated to have a function as a lubricant for smooth contact with the recording / reproducing head. A gravure method or a die coating method is used as a coating method. The component is a fluorine-based lubricant, and perfluoropolyether (for example, trade name “Homblin” manufactured by Montezison) is used.

The back coat layer 54 is formed by dispersing carbon black (particle size: 10 to 100 nm) in a binder (using a PVC, urethane, or nitrocellulose material alone or as a mixture), and applying a gravure method or a reverse method. Alternatively, the film 51 is applied by a die coating method so that the thickness after drying is 0.4 to 1.0 μm.
Is applied to the surface of the magnetic layer 52 on the side opposite to the evaporation surface.

The main role of the back coat layer is as follows. (1) It has conductivity and prevents adhesion of dust by its antistatic effect. (2) Good running stability is obtained by controlling the surface properties (coefficient of friction). (3) Balance of both sides of the magnetic recording medium in terms of hardness and the like to prevent warpage. Conventionally, as a back coat layer, a coating material in which carbon is dispersed in a binder is applied, and the above (1) is controlled by the conductivity of carbon, and the above (3) is controlled by controlling the particle size of carbon and the coating process. (3) was satisfied by controlling the binder and the coating thickness.

[0009]

However, conventionally, even in a vapor-deposited tape, the back coat layer is of a coating type. If the back coat layer is applied first and then the magnetic layer is vacuum-deposited, In a vacuum system, degassing from the back coat layer (generated from the solvent of the binder) is caused, and the degree of vacuum is reduced.

Therefore, conventionally, after depositing the magnetic layer in a vacuum, the tape is taken out to the atmosphere, and then the back coat layer is applied.

However, in this method, in the step of applying the back coat layer, the magnetic layer is damaged, stained, or adhered with dust, so that a drop-out inspection (a certain amount of magnetic tape is put in the cassette deck for inspection, In a test for reproducing a signal while recording the signal and detecting a dropout where the reproduction signal is missing due to a scratch on the tape surface or adhesion of a foreign substance, there is a problem that the number of dropouts is increased.

[0012] Further, although carbon black has good conductivity, there is a problem that the conductivity is lowered due to the addition of a binder, and the antistatic effect is lowered.

Incidentally, it is said that the degree of conductivity required is a resistance value (surface electric resistance) of 10 ⁷ Ω / □ or less (in the case of a commercially available 8 mm video tape). The actual value of the tape is 10 ⁶ Ω / □, but it is not an excellent value, and higher conductivity is desired.

On the other hand, as described above, a fluorine-based lubricant is frequently used for the top coat layer of a metal thin-film type magnetic recording medium. However, the fluorine-based lubricant has a high temperature such as being decomposed at 200 ° C. or more. Because of its weakness and low vapor pressure, application in vacuum is practically impossible.The top coat layer is also formed by a separate application process in air, which is one of the causes of poor productivity. Had become.

In view of such circumstances, the present invention relates to forming a back coat layer on a surface of a non-magnetic support opposite to a surface on which a magnetic layer is deposited, or forming a top coat layer on a magnetic layer. Further, when forming a protective layer and a top coat layer on a magnetic layer, the present invention provides a magnetic recording medium that can solve problems such as adhesion of dust and obtain sufficient performance in terms of performance. It is another object of the present invention to further improve the productivity in manufacturing the magnetic recording medium.

[0016]

Means for Solving the Problems and Functions The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention.

That is, the present invention provides a backcoat layer formed on one surface of a nonmagnetic support, a magnetic layer formed on a surface opposite to the surface on which the backcoat layer is formed, In the production of a magnetic recording medium having a protective layer formed thereon and a top coat layer formed on the protective layer, the back coat layer, the magnetic layer, the protective layer and the top coat layer are And forming the top coat layer while maintaining a vacuum state through a layer forming process.
Is used by atomizing a liquid fluorine-based lubricant, or
An object of the present invention is to provide a method for manufacturing a magnetic recording medium , which is formed by spraying a liquid fluorine-based lubricant . This manufacturing method includes a back coat layer, a magnetic layer,
This is a method in which the four layers of the protective layer and the top coat layer are continuously formed without forming a vacuum state on the way through the steps of forming these layers, that is, through the steps from tape unwinding to tape winding. .

In the method for producing a magnetic recording medium of the present invention, the back coat layer is preferably formed by depositing a metal or a semi-metal in a vacuum.
It is preferable to carry out while introducing an oxidizing gas.

In the method for producing a magnetic recording medium of the present invention, the top coat layer is preferably sprayed with a liquid fluorine-based lubricant, and particularly, atomized by applying ultrasonic waves.
The top coat layer is preferably formed by spraying a liquid fluorine-based lubricant. Further, as the lubricant, a fluorine-based lubricant is preferable.

In the method for producing a magnetic recording medium of the present invention, the magnetic layer is preferably at least one selected from iron, a ferromagnetic alloy mainly composed of iron, and nitrides or carbides thereof.

Hereinafter, the method for manufacturing the magnetic recording medium of the present invention will be described in detail.

[Backcoat layer] In the method of manufacturing a magnetic recording medium of the present invention, the backcoat layer is formed by applying a metal or metalloid in a vacuum to the surface of the nonmagnetic support opposite to the surface on which the magnetic layer is formed. It is formed by attaching. Here, the method of attaching the metal or metalloid in a vacuum is not limited,
Physical vapor deposition (PVD), in particular, thermal evaporation and sputtering.

In addition, since the surface of the back coat layer may be too smooth and the running stability may be deteriorated by merely attaching a metal or metalloid, the friction coefficient of the back coat layer is controlled in such a case. In this case, an oxidizing gas is introduced to adhere to the surface, and the surface is roughened by an oxidizing action. Examples of the oxidizing gas include oxygen, air, and ozone.

Here, the surface electric resistance of the back coat layer is 5 to 10 ⁵ Ω / □, particularly 10 ² to 10 ³ Ω when a metal is used.
It is desirable to set the oxidizing gas introduction amount so as to be / □. In the case of using a semimetal 10 ⁵ ~10 ⁸ Ω /
It is desirable to set the oxidizing gas introduction amount so as to be □, particularly 10 ⁶ to 10 ⁷ Ω / □.

That is, by introducing an oxidizing gas such as oxygen, the bonding of metal or metalloid is weakened and the conductivity is reduced. Therefore, the surface electric resistance value is determined and the amount of the oxidizing gas introduced is determined. Is regulated.

In the case of a metal back coat layer, the surface electric resistance is set to 5 to 10 ⁵ Ω / □ when the surface electric resistance is 5 Ω.
If it is lower than //, the amount of oxygen is small and the coefficient of friction of the back coat layer becomes too high . Surface electric resistance of 10
^{If it} is higher than ⁵ Ω / □, the coefficient of friction will be too low , and the conductivity will be too low , which may lead to adhesion of dust. It should be the goal is approximately 10 ² ~10 ³ Ω / □.
The center line average roughness corresponds to Ra = 4 to 20 nm.

Although various metals can be used as the metal adhered as the back coat layer, Al, Cu, Zn, Sn, Ni, Ag, and alloys thereof are used. However, Al and Cu are most suitable in terms of cost, deposition rate, and stability after oxidation. In addition, as the semimetal forming the back coat layer, Si, G
e, As, Sc, Sb, etc. are used. In particular, Si is most suitable in terms of price, deposition speed, and the like.

The thickness of the back coat layer is 0.05 to 1.0 μm
It is about. The degree of vacuum when performing a thermal evaporation method or a sputtering method for forming a back coat layer is 10 ⁻⁴ to 10 ⁻⁷ Torr
About 10 ^-5 to 10 ^-6 Torr.

[Magnetic Layer] In the method for manufacturing a magnetic recording medium of the present invention, examples of the magnetic material forming the magnetic layer include ferromagnetic metal materials used for manufacturing a normal metal thin film type magnetic recording medium. For example, ferromagnetic metals such as Co, Ni, and Fe, and Fe-Co, Fe-Ni, Co-Ni, Fe-Co-Ni, and Fe-
Fh, Fe-Cu, Co-Cu, Co-Au, Co-Y, Co-La, Co-P
r, Co-Gd, Co-Sm, Co-Pt, Ni-Cu, Mn-Bi, Mn-S
b, Mn-Al, Fe-Cr, Co-Cr, Ni-Cr, Fe-Co-Cr, Ni
-Co-Cr and other ferromagnetic alloys. The magnetic layer is preferably a thin film of iron or a thin film of a ferromagnetic alloy powder mainly composed of iron. In particular, at least one selected from iron, a ferromagnetic alloy mainly composed of iron, and nitrides or carbides thereof.
Species are preferred.

For high-density recording, the magnetic layer of the magnetic recording medium is preferably formed on a substrate by oblique evaporation. The method for oblique deposition is not particularly limited, and follows a conventionally known method. The degree of vacuum at the time of vapor deposition is about 10 ^-4 to 10 ^-7 Torr. The magnetic layer formed by vapor deposition may have either a single layer structure or a multilayer structure. In particular, by introducing an oxidizing gas to form an oxide on the surface of the magnetic layer, the durability can be improved. In the present invention, the magnetic layer can be a single layer or a multilayer. However, when a multilayer magnetic layer is formed by vapor deposition, the thickness of the magnetic layer is two layers, and the thickness of the lower magnetic layer is Is 100-2000 mm, and the thickness of the upper magnetic layer is 50-1000 mm.
In the case of three layers, the thickness of the lower magnetic layer is 100 to
The thickness is preferably 2000 mm, the thickness of the intermediate magnetic layer is 100 to 1000 mm, and the thickness of the upper magnetic layer is 50 to 1000 mm. The number of magnetic layers should be large in order to cope with high-frequency recording, but it is considered that two to five layers are appropriate as a practical range.

[Protective Layer] In the method for manufacturing a magnetic recording medium of the present invention, the protective layer is formed on the magnetic layer in a vacuum, and the protective layer is formed of carbon, carbide, nitride, oxide,
In particular, it is formed by depositing diamond-like carbon, diamond, boron carbide, silicon carbide, boron nitride, silicon nitride, silicon oxide, aluminum oxide or the like on the magnetic layer to form a film. In the present invention, the deposition method for forming the protective layer includes chemical vapor deposition (CV).
Either D) or physical vapor deposition (PVD) may be used. In the CVD method, ECR (Electron Cyclotron Reso
A method using a high frequency (RF) is effective. CV
When the protective layer is formed by the method D, the raw material may be gaseous, liquid or solid. When diamond-like carbon is formed from a gaseous raw material, a mixed gas of methane and argon, a mixed gas of ethane and hydrogen, and a mixed gas of methane and hydrogen are preferably used. In the case where diamond-like carbon is formed from a liquid material, alcohol or unsaturated hydrocarbon is preferably used. Further, when diamond-like carbon is formed from a solid material, naphthalene or higher paraffin is preferably used. In this case, the solid may be heated or ultrasonic waves may be applied.

The PVD method includes a thermal evaporation method, a sputtering method, an ion plating method and the like, and any of them can be used. In the present invention, a sputtering method is particularly effective. When diamond-like carbon is formed by a sputtering method, it is preferable to perform sputtering in a mixed gas of methane and argon or a mixed gas of methane and hydrogen using a graphite target. When forming a protective layer of silicon nitride, the target is silicon,
The discharge gas is preferably a mixed gas of argon and nitrogen, a mixed gas of argon and ammonia, a nitrogen gas, an ammonia gas, a mixed gas of ammonia and monosilane (SiH ₄ ), or the like. In the case of forming a protective layer of aluminum oxide, a target gas is aluminum, and a mixed gas of argon and oxygen is effective as a discharge gas.

The degree of vacuum at the time of vapor deposition is 10 ⁻² to
It is about 10 ^-5 Torr, and in the case of the PVD method, it is about 10 ^-4 to 10 ^-7 Torr. The thickness of the protective layer is not particularly limited, but is 10 to 300.
Å, preferably about 30 to 150 適当.

[Top Coat Layer] In the method for manufacturing a magnetic recording medium of the present invention, the liquid
The basic lubricant is preferably sprayed onto a magnetic layer formed on a non-magnetic support by a sprayer equipped with an ultrasonic oscillator (hereinafter referred to as an ultrasonic sprayer). More specifically, the ultrasonic atomizer includes: a lubricant supply unit; a unit that applies ultrasonic waves to the lubricant supplied from the supply unit to atomize the lubricant (ultrasonic oscillator); Spray nozzle. Further, a nozzle type spraying device may be used.
As the nozzle type spraying device, a device generally called a one-fluid nozzle can be used.

By spraying a lubricant as fine particles using an ultrasonic atomizer, it is weak to high temperatures (200 ° C. or higher) and has a low vapor pressure. Therefore, it is conventionally used for forming a top coat layer by application in air. It is possible to spray a fluorine-based lubricant such as perfluoropolyether in a vacuum.

As the perfluoropolyether, those having a molecular weight of 2,000 to 5,000 are suitable.
DIAC ”[Carboxyl group modification, Montecatini Co., Ltd.
And "FOMBLIN Z DOL" (alcohol-modified, manufactured by Montecatini Co., Ltd.). Since these have a hydroxyl group or a carboxyl group at the terminal, they can enhance the binding between the lubricant and the magnetic layer.
It is particularly preferably used in the present invention.

In addition to these, it is also possible to use a fluorine-based lubricant containing a benzene ring, a double bond, a branched chain, etc., a fatty acid-based lubricant, and other lubricants. However, fluorine-based lubricants are particularly preferably used in the present invention because they improve not only durability but also corrosion resistance as compared with fatty acid-based lubricants.

In spraying the lubricant, the lubricant is sprayed with a fluorine-based inert solvent (for example, perfluorocarbon such as "Fluorinert" manufactured by Sumitomo 3M Limited, or perfluoropolyether such as "Galden" manufactured by Montecatini Co., Ltd.). ), Dissolved in an appropriate solvent such as an aromatic hydrocarbon solvent such as toluene, an alcohol solvent, or a ketone solvent.
It is preferably used as a solution of about 001 to 10% by weight, particularly 0.02 to 2.0% by weight. When using perfluoropolyether as a lubricant, perfluorocarbon can be used as a solvent, and the concentration in that case is 0.001 to 1.0% by weight.
Level, especially 0.05 to 0.2% by weight.

In the method for manufacturing a magnetic recording medium of the present invention, it is desirable that the fine particles of the lubricant (lubricant solution) to be sprayed are as fine as possible, and the frequency of the applied ultrasonic wave depends on the type and viscosity of the lubricant. It is determined, but is generally selected from the range of 20 kHz to 10 MHz.

In the method of manufacturing a magnetic recording medium according to the present invention, the spray amount of the lubricant may be appropriately determined in consideration of the use of the magnetic recording medium, the type of the lubricant, and the like. Preferably, the thickness of the layer is adjusted to be about 10 to 200 mm. The degree of vacuum when spraying the lubricant is about 5 × 10 ^{-4 to} 5 × 10 Torr, preferably 5 × 10 ^{-1 to} 5 × 10 Torr.
× 10 ^-2 Torr.

The top coat layer may be formed on the back coat layer as shown in FIG. By forming the top coat layer on the back coat layer, running properties and durability can be further improved.

[Embodiments of the Manufacturing Method of the Present Invention] Examples of the embodiments of the method of manufacturing the magnetic recording medium of the present invention as described above include, but are not limited to, the following.

(1) A magnetic recording medium characterized in that a metal or metalloid is adhered in a vacuum in forming a back coat layer on a surface of a non-magnetic support opposite to a surface on which a magnetic layer is deposited. Manufacturing method.

(2) A method for producing a magnetic recording medium in which a back coat layer is first formed on a non-magnetic support.

(3) A method for manufacturing a magnetic recording medium in which a magnetic layer is first formed on a non-magnetic support.

(4) A back coat layer formed on one surface of the nonmagnetic support, a magnetic layer formed on the surface opposite to the surface on which the back coat layer is formed, and In the production of a magnetic recording medium having a formed protective layer and a top coat layer formed on the protective layer, a non-magnetic support is run in a vacuum, and a metal or a metal is coated on one surface of the non-magnetic support. A backcoat layer is formed by depositing a semimetal, and then a magnetic layer is formed by depositing a magnetic material on the surface of the non-magnetic support opposite to the surface on which the metal backcoat layer is formed. Forming a protective layer on the magnetic layer by CVD or PVD, and then spraying a lubricant on the protective layer to form a top coat layer.

(5) A back coat layer formed on one surface of the non-magnetic support, a magnetic layer formed on a surface opposite to the surface on which the back coat layer is formed, and In the production of a magnetic recording medium having a formed protective layer and a top coat layer formed on the protective layer, a non-magnetic support is run in a vacuum, and on one surface of the non-magnetic support,
A magnetic layer is formed by attaching a magnetic material, then a protective layer is formed on the magnetic layer by a CVD method or a PVD method, and then a lubricant is sprayed on the protective layer to form a top coat layer. Then, a metal or metalloid is adhered to the surface of the non-magnetic support opposite to the surface on which the magnetic layer is formed to form a back coat layer.

(6) A back coat layer formed on one surface of the nonmagnetic support, a magnetic layer formed on the surface opposite to the surface on which the back coat layer is formed, and In the production of a magnetic recording medium having a formed protective layer and a top coat layer formed on the protective layer, a non-magnetic support is run in a vacuum, and on one surface of the non-magnetic support,
Forming a magnetic layer by depositing a magnetic material, and then forming a backcoat layer by depositing a metal or metalloid on the surface of the nonmagnetic support opposite to the surface on which the magnetic layer is formed. Then, CVD on the magnetic layer
A method for producing a magnetic recording medium, wherein a protective layer is formed by a method or a PVD method, and then a lubricant is sprayed on the protective layer to form a top coat layer.

(7) A method of manufacturing a magnetic recording medium in which the steps of (1) to (6) are continuously performed while maintaining a vacuum state.

And the like.

In the method for producing a magnetic recording medium of the present invention, non-magnetic supports include polyesters such as polyethylene terephthalate and polyethylene naphthalate; polyolefins such as polyethylene and polypropylene; celluloses such as cellulose triacetate and cellulose diacetate. Derivatives; polycarbonate; polyvinyl chloride; polyimide; plastics such as aromatic polyamide, and the like are used. The thickness of these nonmagnetic supports is 3 to
It is about 50 μm.

[Manufacturing Apparatus A of the Present Invention] The present invention also provides a non-magnetic device including a housing having first, second, third, and fourth chambers, and vacuum means for keeping the respective chambers at a vacuum. An apparatus for manufacturing a magnetic recording medium having a magnetic layer formed on a support, wherein each of the chambers is arranged in the order of first, second, third, and fourth chambers, or first, second, and third chambers.
The second, fourth, and third chambers are arranged adjacent to each other in this order;
Adjacent chambers are communicated with each other via a non-magnetic support passage opening, and the first chamber has a first cooling can for transporting the non-magnetic support, and a first cooling can below the first cooling can. A first vapor deposition means disposed therein, wherein the second chamber has a second cooling can for transporting a non-magnetic support, and a second cooling can disposed below the second cooling can. The third chamber has a third cooling can for transporting the non-magnetic support, and a third vapor deposition means disposed below the third cooling can. The fourth chamber has a heating can for transporting the nonmagnetic support, and a liquid fluorine-based lubricant spraying means disposed below the heating can. A manufacturing apparatus (the manufacturing apparatus A of the present invention) is provided.

In the manufacturing apparatus A of the present invention, a vacuum means such as a vacuum pump can be used as the vacuum means. In addition, the nonmagnetic support passage opening usually includes a slit communicating each chamber.

The manufacturing apparatus A of the present invention forms a magnetic layer, a protective layer, and a back coat layer in the first, second, and third chambers, and forms a top coat layer in the fourth chamber. , The arrangement of the chambers is in the first, second, third, fourth order, or the first, second, fourth, third order. The arrangement of the chambers in the manufacturing apparatus A of the present invention is schematically shown below, where ~ means the first to fourth chambers, respectively. (A) Magnetic layer → protective layer → back coat layer → top coat layer (b) Magnetic layer → back coat layer → protective layer → top coat layer (c) Back coat layer → magnetic layer → protective layer → top coat layer (d) ) Magnetic layer → protective layer → top coat layer → back coat layer For each chamber, a metal material, a magnetic material, a carbide, an oxide, etc. are selected according to the layer to be formed. Further, as the manufacturing apparatus A of the present invention, the first chamber has a first oxidizing gas introducing means for introducing an oxidizing gas during or after the vapor deposition, and the second or the third chamber is provided. An apparatus having a second oxidizing gas introducing means for introducing an oxidizing gas after or during vapor deposition is preferable. Each of the oxidizing gas introducing means includes an oxidizing gas introducing pipe and a suitable opening. In addition, the manufacturing apparatus A of the present invention includes a transport roller and a shielding plate that defines the inside of the chamber, if necessary.

An example of the manufacturing apparatus A of the present invention will be described below.

(1) The first and / or the second and / or the third vapor deposition means comprises a metal material container opened to the first, the second or the third cooling can, An apparatus for manufacturing a magnetic recording medium according to the present invention, including an electron beam generator for irradiating a metal material in the container with an electron beam.

(2) The first, second or third chamber according to the present invention, further comprising a first nitrogen ion supply means for supplying nitrogen ions or a mixed gas of nitrogen ions and nitrogen during vapor deposition. Equipment for manufacturing magnetic recording media. The nitrogen ion supply means is provided in a chamber for forming a magnetic layer,
The supplied nitrogen ions react with the vapor of the magnetic metal to generate metal nitride, and a magnetic layer composed of a metal nitride thin film is formed on the nonmagnetic support. The above-mentioned oxidizing gas introducing means is arranged at a position for oxidizing the surface of the magnetic layer.

(3) The first, second, or third chamber further includes a fourth vapor deposition means disposed below the first, second, or third cooling can, and A second nitrogen ion supply means for supplying nitrogen ions during vapor deposition by the vapor deposition means; a third oxidizing gas introducing means for introducing an oxidizing gas after vapor deposition by the fourth vapor deposition means; Second
Alternatively, the apparatus for manufacturing a magnetic recording medium according to the above (2), further comprising means for defining a deposition area of the third vapor deposition means and the fourth vapor deposition means. The fourth vapor deposition means, the second nitrogen ion supply means, and the third oxidizing gas introduction means are provided in a chamber where the magnetic layer is formed.

[0059] (4) the in the fourth chamber fluoride
The apparatus for manufacturing a magnetic recording medium according to the present invention, wherein the means for spraying the basic lubricant includes an ultrasonic oscillator and a spray nozzle.

(5) The fourth chamber further comprises fluorine
An apparatus for manufacturing a magnetic recording medium according to the present invention, comprising: means for heating a nonmagnetic support to which a system lubricant has been sprayed. As a means for heating the non-magnetic support on which the lubricant is sprayed, a heating lamp is appropriate, and the installation position is not particularly limited as long as the non-magnetic support on which the lubricant is sprayed can be heated. Absent. When the non-magnetic support is heated by a heating lamp, the heating temperature is optimally 80 to 100 ° C.

The manufacturing apparatus A of the present invention comprises a back coat layer,
The magnetic layer, the protective layer on the magnetic layer, and the top coat layer on the protective layer can be formed continuously in vacuum without returning the vacuum system to air pressure and shifting to another line. Manufacturing apparatus A of the present invention
Has a very high productivity and can prevent dust from adhering to the non-magnetic support in the air.

[Production apparatus B of the present invention]
Means for forming a first layer on a support in a first chamber held in a vacuum, and then on the support or on the first layer in a second chamber held in a vacuum Means for forming a second layer on the support, then forming a third layer on the support, on the first layer or on the second layer in a third chamber held in vacuum Means and then the second chamber in a fourth chamber held in vacuum.
Means for forming a fourth layer on the first layer or on the third layer; means for transferring the support from the first chamber to the second chamber; and means for transferring the support from the second chamber to the second chamber. It is an object of the present invention to provide an apparatus for manufacturing a magnetic recording medium, comprising: means for transferring the support to a third chamber; and means for transferring the support from the third chamber to the fourth chamber. .

This manufacturing apparatus B is an apparatus for forming four layers of a back coat layer, a magnetic layer, a protective layer and a top coat layer constituting a magnetic recording medium in a vacuum. Each chamber has a means capable of forming a target layer. Specifically, each chamber can have the elements described in the manufacturing apparatus A.

[Magnetic Recording Medium of the Present Invention] In the present invention, a backcoat layer formed on one surface of a nonmagnetic support and a surface opposite to the surface on which the backcoat layer is formed are formed. In a magnetic recording medium having a magnetic layer, a protective layer formed on the magnetic layer, and a top coat layer formed on the protective layer, the back coat layer, the magnetic layer, the protective layer, and the top layer It is intended to provide a magnetic recording medium wherein the coat layer is formed in a vacuum. The magnetic recording medium of the present invention is characterized in that four layers of a back coat layer, a magnetic layer, a protective layer and a top coat layer are formed in a vacuum.

As a method for forming the magnetic layer and the back coat layer in a vacuum, a PVD method such as thermal evaporation or sputtering can be used. The metal forming the back coat layer, the metalloid, the magnetic material forming the magnetic layer, the type of the nonmagnetic support, the thickness of each layer, and the like are in accordance with the manufacturing method of the present invention described above.

The protective layer is made of PVD by thermal evaporation, sputtering, etc.
It can be formed by a method or a CVD method, and conforms to the manufacturing method of the present invention described above. Further, the top coat layer is desirably formed by spraying a lubricant in a vacuum, and the type of the lubricant, the spraying method, and the like are in accordance with the manufacturing method of the present invention described above.

In the magnetic recording medium of the present invention, the back coat layer is preferably a metal or metalloid or a vapor deposited layer of these oxides. When the back coat layer is made of a metal or an oxide thereof, the back coat layer preferably has a surface electric resistance of 5 to 10 ⁵ Ω / □. When the back coat layer is made of a semimetal or its oxide, the back coat layer preferably has a surface electric resistance of 10 ⁵ to 10 ⁸ Ω / □. In particular, the magnetic recording medium of the present invention in which the back coat layer is formed of a semi-metal has an advantage in that it can be manufactured in a vacuum, and further has an improved envelope characteristic. This is considered to be because the formation of the back coat layer with a semi-metal gives the magnetic recording medium an appropriate elasticity and appropriately maintains the degree of contact (per unit) between the magnetic recording medium and the reproducing head.

[0068]

Embodiments of the present invention will be described below. However, the invention is not limited to these examples.

Example 1 (i) Manufacturing Apparatus FIG. 1 is a schematic view showing an example of an apparatus for manufacturing a magnetic recording medium according to the present invention, in which a back coat layer, a magnetic layer, and a protective layer are formed first. Finally, a top coat layer is formed.

The housing 1 is defined by a first chamber 2, a second chamber 3, a third chamber 4, and a third chamber 5. Each chamber is connected to a vacuum means (not shown) to maintain an appropriate degree of vacuum. In addition,
The degree of vacuum in each chamber is appropriately determined depending on the material to be adhered and the like, and all may be the same or different.

The first chamber 2 has an unwinding roll 6
A first cooling can 7 for transporting the nonmagnetic support 9,
It has a feed roll 8, first vapor deposition means, and a first oxygen gas introduction pipe 14. Further, the bombardment device 10 is used to prevent fine dust and dirt from adhering to the non-magnetic support that has exited the unwinding roll 6 or the non-magnetic support that enters the feed roll 8.
10 'is installed.

The first vapor deposition means in the first chamber 2 comprises a crucible 11 and an electron gun 13 disposed below the first cooling can 7, and this crucible 11 opens to the cooling can 7. The metal aluminum 12 serving as the back coat layer is accommodated in the recess. An electron beam is emitted from the electron gun 13, and the electron beam irradiates the aluminum 12 of the crucible 11. Further, oxygen gas is introduced into the evaporation region of the aluminum vapor through the first oxygen gas introduction pipe 14 to oxidize aluminum, and a thin film of aluminum oxide is formed as a back coat layer. The oxygen introduction amount can be adjusted by a flow control valve (not shown).

The non-magnetic support 9 on which the back coat layer is formed is conveyed on the feed roll 8 and guided to the second chamber 3 through the slit 32 which is an opening for passing the non-magnetic support.

The second chamber 3 includes feed rolls 15, 15 '
And a second cooling can 16 on which the nonmagnetic support 9 runs. FIG. 1 shows an apparatus in which the second chamber has a second vapor deposition means and a fourth vapor deposition means.

The second vapor deposition means comprises a crucible 17 and an electron gun 19 disposed below the second cooling can 16, and the crucible 17 is open to the second cooling can 16. The metal iron 18 to be the magnetic layer is accommodated in the recess. Electron gun
An electron beam is launched from 19, and this electron beam is
Irradiation is performed on metal iron 18 in 17.

Further, nitrogen ions are supplied from the first nitrogen ion supply means 20 into the iron evaporation region to nitride the evaporated iron, which adheres to the non-magnetic support, and the iron nitride thin film is formed. Formed on a magnetic support.

Next, from the second oxygen gas introducing pipe 14 ′,
After the vapor deposition, an oxygen gas is supplied to oxidize the vicinity of the surface of the magnetic layer. In the second chamber, the oxygen gas introduction pipe needs to be installed at a position where the surface of the magnetic layer can be oxidized immediately after the iron nitride adheres to the nonmagnetic support.

The fourth vapor deposition means, like the second vapor deposition means, also has a crucible 17 ′ disposed below the second cooling can 16.
The crucible 17 'is open to the second cooling can 16, and a metal iron 18' serving as a magnetic layer is accommodated in the concave portion. An electron beam is emitted from an electron gun 19 ', and this electron beam is applied to a metallic iron 18' in a crucible 17 '.
Is to be irradiated.

Further, nitrogen ions are supplied into the iron evaporation region from the second nitrogen ion supply means 20 ′ to nitride the evaporated iron, which adheres to the non-magnetic support, and a thin film of iron nitride is formed. Formed on a non-magnetic support.

Next, from the third oxygen gas introduction pipe 14 ″,
After the vapor deposition, an oxygen gas is supplied to oxidize the vicinity of the surface of the magnetic layer. In this apparatus, the second oxygen gas introduction pipe 14 'and the third oxygen gas introduction pipe 14''are constituted by branch pipes connected to the same oxygen supply source.

The means for defining the region of the metal vapor generated from the second vapor deposition means and the fourth vapor deposition means is the shielding plate 37, which is usually made of a metal plate.

In the present apparatus, two magnetic layers having corundum tilt directions different from each other are formed. The non-magnetic support 9 on which the magnetic layer is formed is conveyed on the feed roll 15 'and guided to the third chamber 4 through the slit 32'.

The third chamber 4 includes feed rolls 21 and 21 ′
And a third cooling can 22 on which the nonmagnetic support 9 runs. In FIG. 1, a protective layer is formed by a CVD method in a third chamber.

The third vapor deposition means is a CVD device disposed below the third cooling can 22, and is a gas introduced from the gas inlet 25, for example, a mixed gas such as methane and hydrogen or methane and argon. Is a microwave oscillator 24 and a magnet
Chamber 4 excited by plasma generated from 23,23 '
Active species (such as carbon and nitride) adhere to the magnetic layer of the non-magnetic support 9 which is radiated inside and travels on the cooling can 22.
The non-magnetic support 9 on which the protective layer is formed is conveyed on the feed roll 20 'and guided to the fourth chamber 5 through the slit 32''.

The fourth chamber 5 has feed rolls 26, 26 '.
A heating can 27 for transporting the non-magnetic support 9; a winding roll 28; Here, the spraying means of the lubricant includes an ultrasonic spraying device 29 and a spray nozzle 30, and is disposed below the heating can 27 and on the left side of the drawing. The lubricant is atomized by ultrasonic waves and spray nozzle 30
Is sprayed onto the non-magnetic support 9 running on the heating can 27 to form a top coat layer on the protective layer formed on the magnetic layer. Further, in the present apparatus, the fourth chamber has a heating lamp 31 to promote drying of the lubricant sprayed on the non-magnetic support.

The non-magnetic support 28 on which the top coat layer has been formed is conveyed on the feed roll 26 ′ and wound up by the take-up roll 28.

(Ii) Production of Magnetic Recording Medium Using a device shown in FIG. 1, a back coat layer, a magnetic layer, a protective layer and a top coat layer were formed on a non-magnetic support.

First, the cooling can 7 in the first chamber 2
A PET film having a thickness of 9.8 μm is run thereon, and Fe (iron) is vapor-deposited on the PET film by a first vapor deposition means so as to have a thickness of 1000 mm while introducing oxygen (10 cc / min). Then, a back coat layer was formed.

Next, the cooling can 16 in the second chamber 3
The PET film is run thereon, and oxygen (3 cc) is introduced on the surface opposite to the surface on which the back coat layer is formed by a second vapor deposition means so that Fe (iron) becomes 800 mm thick (3 cc). / Min). During the vapor deposition, nitrogen ions were supplied from the nitrogen ion supply means 20. Thus, the first magnetic layer was formed, and thereafter, similarly, the second magnetic layer was formed in the second chamber by the fourth vapor deposition means.

Next, the cooling can 22 in the third chamber 4
Run the PET film on top, and on the magnetic layer,
A protective layer was formed using a CVD apparatus. CV used in this example
The D device has a 2.5 GHz microwave oscillator 24. As the protective layer, a mixed gas of methane and argon (4: 1) was introduced at a rate of 25 cc / min into the quartz chamber where plasma was created, microwave power was sent to cause discharge, and a protective layer made of diamond-like carbon was formed. Formed. At that time, the microwave power was 500 W, the degree of vacuum was 5 × 10 ⁻³ Torr, and the deposition rate was 9
Å / sec. Further, methane and argon each having a purity of 99.99% were used. The thickness of the protective layer was 100 mm. This was measured by Auger electron spectroscopy.

Next, the heating can 27 in the fourth chamber 5
Run the PET film on the top and use `` FOMB
LIN Z DIAC ”[Carboxy group modified, Montecatini
Was sprayed onto the protective layer of the PET film so as to have a thickness of 30 mm using an ultrasonic spraying means, and a top coat layer was formed.

(Iii) Evaluation of Performance of Magnetic Recording Medium The film on which the back coat layer, the magnetic layer, the protective layer and the top coat layer were formed as described above was cut into a tape having a width of 8 mm, placed in a cassette case, and placed in a cassette case. A cassette tape was obtained. Still durability was measured as a measure of durability. The still durability was measured by using a commercially available high-band 8 mm VTR, setting the 8 mm video cassette tape in a still state for 1 hour, and measuring the decrease in output at 7 MHz. As a result, 7MH
The decrease in the output of z was 0.2 dB.

The composition of the protective layer was analyzed by EELS (Electron Energy Loss Spectroscopy) to confirm that the film forming the protective layer was diamond-like carbon. FIG. 2 shows an EELS chart. From this chart, it was confirmed that the substance forming the protective layer was an intermediate substance between diamond and graphite, and was a good diamond-like carbon.

Example 2 A magnetic recording medium having a back coat layer, a magnetic layer, a protective layer, and a top coat layer was manufactured using the same apparatus as in Example 1. However, as shown in FIG. 3, the third chamber in the present embodiment is provided with a PVD apparatus (DC magnetron sputtering apparatus) disposed below the cooling can 22 as a third vapor deposition means. The target is silicon and the output is 5 kW.

In the first chamber and the second chamber, the non-magnetic support member 9 having the back coat layer and the magnetic layer formed thereon is caused to travel into the third chamber, and the mixed gas of argon and nitrogen is supplied from the gas inlet 35. (1: 4) introduced (15cc / min)
Then, a protective layer made of silicon nitride was formed on the magnetic layer.
The thickness of the protective layer was 110 °. This was measured by Auger electron spectroscopy. Thereafter, a top coat layer was formed on the protective layer, and an 8 mm video cassette tape was obtained in the same manner as in Example 1.

When the still durability of the obtained 8 mm video cassette tape was measured in the same manner as in Example 1, the decrease in output at 7 MHz was 0.4 dB.

Comparative Example 1 In Example 1, after forming a magnetic layer on a film,
The film was wound up and once taken out to the atmosphere to form a protective layer. Then, as in the first embodiment, 8 mm
When a video cassette tape was manufactured and the still durability was measured in the same manner as in Example 1, the decrease in output at 7 MHz was 0.7
dB.

Comparative Example 2 In Example 1, only the three layers of the back coat layer, the magnetic layer and the top coat layer on the magnetic layer were formed without forming the protective layer. Thereafter, an 8 mm video cassette tape was manufactured in the same manner as in Example 1, and the still durability was measured in the same manner as in Example 1. As a result, the decrease in output at 7 MHz was 1.4 dB.

[0099]

As described above, according to the present invention, since the back coat layer is formed by vapor deposition in a vacuum, problems such as adhesion of dust can be solved.

According to the present invention, the back coat layer, the magnetic layer, the protective layer and the top coat layer of the metal thin film type magnetic recording medium can be continuously formed in a vacuum, so that the productivity is very high. Become.

When the back coat layer is formed by simple vacuum evaporation, the surface may be too smooth and the running stability may be deteriorated. However, an oxidizing gas is introduced at the time of evaporation and the friction coefficient of the back coat layer is reduced. By controlling, the running stability can be maintained. Moreover, by introducing the oxidizing gas, not only the surface roughness can be controlled, but also the corrosion resistance can be improved. The introduction of the oxidizing gas weakens the metal bond and lowers the conductivity. However, the conductivity can be maintained by determining the surface electric resistance and regulating the amount of the oxidizing gas introduced.

Further, by forming a protective layer on the magnetic layer, the durability is improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an apparatus for manufacturing a magnetic recording medium according to the present invention.

FIG. 2 shows the protective layer of the magnetic recording medium obtained in Example 1.
EELS chart

FIG. 3 is a schematic view showing another example of the magnetic recording medium manufacturing apparatus of the present invention.

FIG. 4 is a model diagram showing a configuration of a vapor deposition tape.

FIG. 5 is a model diagram showing an example of the configuration of a vapor deposition tape of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 housing 2 first chamber for forming back coat layer 3 second chamber for forming magnetic layer 4 third chamber for forming protective layer 5 fourth chamber for forming top coat layer 24 microwave oscillator 29 Ultrasonic atomizer 30 Spray nozzle 34 Sputter power supply 36 Target

────────────────────────────────────────────────── ─── of the front page continued (51) Int.Cl. ⁶ identification symbol FI G11B 5/84 G11B 5/84 B (58 ) investigated the field (Int.Cl. ^6, DB name) G11B 5/85 B05B 17 / 06 B05D 7/24 C23C 14/14 G11B 5/66 G11B 5/84

Claims (15)

(57) [Claims] 1. A backcoat layer formed on one surface of a nonmagnetic support, a magnetic layer formed on a surface opposite to the surface on which the backcoat layer is formed, and a backcoat layer formed on the magnetic layer. In the production of a magnetic recording medium having a protective layer and a top coat layer formed on the protective layer, the back coat layer, the magnetic layer, the protective layer and the top coat layer are formed by using A method for manufacturing a magnetic recording medium, comprising: forming a top coat layer while maintaining a vacuum state throughout a forming step; and forming the top coat layer by atomizing a liquid fluorine-based lubricant. 2. A bag formed on one surface of a non-magnetic support.
And a surface on which the back coat layer is formed.
A magnetic layer formed on the opposite surface; and a magnetic layer formed on the magnetic layer.
Protective layer, and a top coat layer formed on the protective layer.
In the manufacture of a magnetic recording medium having
Layer, the magnetic layer, the protective layer, and the top coat layer
While maintaining a vacuum state throughout the process of forming these layers.
And the top coat layer is formed of a liquid fluorine-based
Characterized by spraying lubricant
A method for manufacturing a magnetic recording medium. 3. The method according to claim 1, wherein the top coat layer is formed by applying an ultrasonic wave.
By spraying atomized liquid fluorine-based lubricant
3. The magnetic recording medium according to claim 2, wherein the magnetic recording medium is formed.
Manufacturing method. 4. The back coat layer according to claim 1, wherein a metal or metalloid is adhered to one surface of the non-magnetic support in a vacuum by a physical vapor deposition method (PVD method). 4. The method for manufacturing a magnetic recording medium according to any one of claims 1 to 3 . 5. The method according to claim 4 , wherein the back coat layer is formed by introducing an oxidizing gas. Wherein said magnetic layer is iron, a ferromagnetic alloy and the magnetic recording medium of any one of claims 1 to 5 is at least one selected from these nitrides or carbides mainly of iron Manufacturing method. 7. The method according to claim 1, wherein the back coat layer is first formed on a non-magnetic support. 8. The method according to claim 1, wherein the magnetic layer is first formed on a non-magnetic support. 9. A magnetic apparatus comprising: a housing having first, second, third, and fourth chambers; and a vacuum means for maintaining the chambers in a vacuum, wherein a magnetic layer is formed on a nonmagnetic support. An apparatus for manufacturing a recording medium, wherein each of the chambers is arranged adjacent to a first, second, third, and fourth chamber or in order of first, second, fourth, and third chambers. Adjoining chambers are communicated with each other via a non-magnetic support passage opening; the first chamber has a first cooling can for transporting the non-magnetic support, and a first cooling can below the first cooling can And a first vapor deposition means disposed in the second chamber. The second chamber has a second cooling can for transporting a non-magnetic support, and a second cooling can disposed below the second cooling can. And a third cooling unit for transporting a non-magnetic support. And a third vapor deposition means disposed below the third cooling can. The fourth chamber includes a heating can for transporting a non-magnetic support, and a lower portion below the heating can. An apparatus for manufacturing a magnetic recording medium, comprising: means for spraying a liquid fluorine-based lubricant disposed in a magnetic recording medium. 10. The first chamber has first oxidizing gas introducing means for introducing an oxidizing gas during or after vapor deposition, and the second or third chamber is provided after or during vapor deposition. 10. The apparatus for manufacturing a magnetic recording medium according to claim 9, further comprising a second oxidizing gas introducing unit for introducing an oxidizing gas into the magnetic recording medium. 11. The first and / or the second and / or the third.
A metal material container opened to the first, second or third cooling can, and an electron beam generator for irradiating the metal material in the container with an electron beam. apparatus for manufacturing a magnetic recording medium according to claim 9 or 10, wherein comprising a. 12. The first, second or third chamber comprises:
Further, apparatus for manufacturing a magnetic recording medium of any one of claims 9-11 having a first nitrogen ion supplying means for supplying nitrogen ions during the deposition. 13. The first, second or third chamber comprises:
A fourth vapor deposition means disposed below the first, second, or third cooling can; and a second nitrogen ion supply means for supplying nitrogen ions during vapor deposition by the fourth vapor deposition means. A third oxidizing gas introducing unit for introducing an oxidizing gas after the vapor deposition by the fourth vaporizing unit; and a vapor deposition region of the first, second or third vapor deposition unit and the fourth vapor deposition unit. 13. The apparatus for manufacturing a magnetic recording medium according to claim 12, further comprising means for defining. 14. Spray means of the fluorine-based lubricant, claims 9-13 is intended to include ultrasonic oscillator and spraying nozzle
An apparatus for manufacturing a magnetic recording medium according to any one of the preceding claims. 15. The fourth chamber, further a fluorine-based lubricant apparatus for manufacturing a magnetic recording medium according to any one of claims 9 to 14 having a means for heating the non-magnetic support which is sprayed .