JP2003085742A - Method of manufacturing magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a magnetic recording medium having an excellent rust preventive effect an excellent reliability of durability, traveling stability, etc. SOLUTION: Formation of a lubricant layer is performed by a dry treatment in a vacuum chamber 502 in the method of manufacturing the magnetic recording medium comprising forming the lubricant layer across a magnetic layer on a nonmagnetic substrate 1. At this time, a vaporized lubricant L is sprayed together with a carrier gas to a protective film formed across the magnetic layer on the nonmagnetic substrate 1. The vaporization of the lubricant L is performed by applying ultrasonic vibrations to the lubricant L which is heated or is vaporized by heating. The lubricant layer is formed on a surface subjected to an amination treatment. The amination treatment is performed within the vacuum chamber 502 and the formation of the lubricant layer is performed in succession to the amination treatment without exposing the surface subjected to the amination treatment to the atmospheric air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a magnetic recording medium, and more particularly to an improvement in a method for manufacturing a magnetic recording medium having a lubricant layer on the outermost surface.

[0002]

2. Description of the Related Art As a tape-shaped magnetic recording medium such as an audio tape or a video tape, a powder magnetic material such as an oxide magnetic powder or an alloy magnetic powder is placed on a non-magnetic support in a vinyl chloride-vinyl acetate system. A coating type magnetic recording medium prepared by coating and drying a magnetic coating material dispersed in an organic binder such as a coalescence, polyester resin, urethane resin or polyurethane resin is widely used. On the other hand, with the increasing demand for high-density magnetic recording,
A metal magnetic material such as a Co-Ni alloy, a Co-Cr alloy, or Co-O is coated with polyester, polyamide, polyimide, etc. by plating or vacuum thin film forming means (vacuum deposition method, sputtering method, ion plating method, etc.). A magnetic recording medium of a so-called metal magnetic thin film type, which is directly deposited on a non-magnetic support made of, has been proposed and has attracted attention.

This metal magnetic thin film type magnetic recording medium is excellent not only in coercive force and squareness ratio but also in electromagnetic conversion characteristics at short wavelengths, and because the magnetic layer can be made extremely thin,
There are many things such as remarkably small thickness loss during recording demagnetization and reproduction, and increasing the packing density of the magnetic material because it is not necessary to mix the binder (binding agent) that is a non-magnetic material into the magnetic layer. Have the advantages of. Further, in order to improve the electromagnetic conversion characteristics of this kind of magnetic recording medium and to obtain a larger output, when forming the magnetic layer of the magnetic recording medium, the so-called oblique vapor deposition of the magnetic layer is called. Oblique vapor deposition has been proposed and already put to practical use.

Such a tape-shaped magnetic recording medium includes
In addition to the non-magnetic support and the magnetic layer, a protective layer is provided on the magnetic layer for the purpose of improving durability and running property, or the side opposite to the side of the non-magnetic support on which the magnetic layer is formed. A back layer is usually provided on the side surface.

The protective layer protects the magnetic layer from sliding on the reproducing magnetic head. In magnetic recording media, the surface tends to be smoother in order to suppress spacing loss in response to higher density. However, when the surface of the magnetic layer becomes smooth, the contact area with the head increases, so that the frictional force increases and the shear stress generated in the magnetic layer increases. The protective layer is important for protecting the magnetic layer from such severe sliding conditions.

The back layer lowers the electric resistance of the surface of the non-magnetic support to prevent running defects due to charging, enhances the durability of the non-magnetic support, and prevents scratches during use. It is also provided for the purpose of reducing friction between magnetic recording media. In order to improve the running property and durability of the tape-shaped magnetic recording medium, it is essential to form this back layer.

In order to prevent the magnetic layer from being damaged by the frictional force acting between the magnetic layer and the magnetic head when the magnetic layer slides on the protective layer, the protective layer is instantaneously scraped off. A lubricant layer is provided for the purpose of reducing the friction coefficient. On the other hand, on the back layer side as well, in order to avoid peeling of the back layer and surface damage due to sliding with the guide due to the tape path, a lubricant for the purpose of reducing the friction coefficient is applied, or inside the back layer It is provided internally.

By the way, with the recent increase in recording density, a system using a magnetoresistive (MR) head as a reproducing head has been introduced, and many attempts have been made to reduce the noise of the medium. One of them is smoothing of surface properties. That is, in the method of forming a magnetic layer by vapor deposition of a metal film as described above, the surface property of the non-magnetic support is directly reflected on the outermost surface of the magnetic recording medium even after forming the magnetic layer and the protective layer. It Therefore, in order to reduce the medium noise, it is essential to make the surface of the non-magnetic support body a mirror surface.

However, due to this mirror surface, the contact area between the outermost surface of the magnetic recording medium and the reproducing head, the guide pin, etc. is increased, causing an increase in friction and eventually damage such as peeling of the surface protective layer. . This is because the lubricant layer existing on the surface cannot be fixed to the surface by sliding on a smooth (mirror-finished) surface and is easily peeled off. As a countermeasure against this, the surface of the protective layer is subjected to an amination treatment to enhance the binding force between the protective layer and the lubricant layer (JP-A-6-103560, JP-A-6-103560).
000423357, JP-A-2000-123349, and JP-A-2000-123358).

When manufacturing a magnetic recording medium having such a structure, a magnetic layer is obliquely vapor-deposited on a non-magnetic support, and a protective film is further formed on the magnetic layer, and then the back surface of the non-magnetic support ( A back coat layer is formed on the surface opposite to the surface on which the magnetic layer is formed. Then, an organic compound having an amino group is applied to the surface of the protective layer in the atmosphere to perform an amination treatment. Then, a lubricant coating in which a lubricant is dissolved in an organic solvent is applied on the amination-treated surface, and then the organic solvent in the coating film is volatilized and removed by a dryer, whereby the lubricant layer is formed. Is forming.

[0011]

However, the above-described method of manufacturing a magnetic recording medium has the following problems. That is, in forming the lubricant layer, a coating film is formed by using a lubricant paint dissolved in an organic solvent, but in the process of handling the organic solvent, the process atmosphere is set high to prevent ignition due to static electricity. Need for humidity. For this reason,
In the coating process of lubricant paint, a large amount of adsorbed water is generated on the film-forming surface exposed to the high-humidity atmosphere, and the applied lubricant paint using an organic solvent that is not compatible with water is applied to the surface of the protective film. It could not be applied uniformly, resulting in non-uniform film formation of the lubricant layer.

This is a factor that reduces the effect of improving the durability due to the formation of the lubricant layer. If a corrosive gas such as SO ₂ is present as a result of the non-uniform film formation of the lubricant layer, the magnetic layer metal that has been easily ionized due to the potential difference between the lubricant layer and the protective film dissolves and corrosion progresses.
The magnetization deterioration rate could not be suppressed to a sufficiently low level.

Further, in the film formation in the atmosphere, many dust particles floating in the atmosphere are apt to adhere to the lubricant layer, which causes dropout and head clogging. Moreover, the final film thickness of the lubricant layer cannot be strictly controlled, and the resulting surplus lubricant causes friction increase and head contamination. This is a factor that deteriorates the running stability of the head during recording and reproduction using a magnetic recording medium.

Even when the surface of the protective film is subjected to an amination treatment, the amination treatment is carried out by coating an organic compound having an amino group in the atmosphere, and therefore the amination treatment is performed on the surface. Amine salts exposed to the atmosphere. Therefore, the effect of improving the adhesiveness of the lubricant layer by the amination treatment cannot be sufficiently obtained, and it is difficult to obtain a stable and durable magnetic recording medium.

As described above, in the method of manufacturing a magnetic recording medium in which a lubricant is applied to form a film, M
It was not possible to obtain a high-density magnetic recording medium on the assumption that the R head was used.

Therefore, according to the present invention, it is possible to form a lubricant layer having excellent uniformity, and thereby, a method for producing a magnetic recording medium having an excellent rust preventive effect and excellent reliability such as durability and running stability. The purpose is to provide.

[0017]

[Means for Solving the Problems]

The present invention for achieving the above object provides a method for producing a magnetic recording medium, which comprises forming a protective film on a non-magnetic support via a magnetic layer and forming a lubricant layer on the protective film. The formation of the lubricant layer is characterized by being performed in a vacuum atmosphere and by spraying a vaporized lubricant together with a carrier gas.

In such a manufacturing method, the lubricant layer is formed without being affected by the adsorbed moisture on the film-forming surface. Therefore, a magnetic recording medium having a uniform lubricant layer can be obtained.

Further, by forming the lubricant layer on the amination-treated surface, the lubricant layer can be formed with good adhesion. At this time, particularly, by performing the amination treatment in a vacuum atmosphere and forming the lubricant layer continuously with the amination treatment, the adhesion of the lubricant layer to the amination-treated surface can be further strengthened.

[0021]

FIG. 1 is a schematic configuration diagram of a magnetic recording medium formed by a method for manufacturing a magnetic recording medium according to the present invention. The embodiment of the present invention will be described in detail below with reference to this figure. explain. Here, the embodiment will be described taking the case of manufacturing a tape-shaped magnetic recording medium as an example.

First, the non-magnetic support 1 is prepared. The non-magnetic support 1 may be of any type as long as it is used for ordinary vapor deposition tapes. Generally, polyester type is mainly used, but as the polyester, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polytetramethylene terephthalate, poly-1,4-cyclohexylene dimethylene terephthalate, Examples thereof include polyethylene-2,6-naphthalene dicarboxylate and polyethylene-p-oxybenzoate. Especially polyethylene terephthalate (PET), polyethylene naphthalate (PE
N) is preferred. Further, these polyesters may be homopolyesters or copolyesters.

Further, the surface of the non-magnetic support 1 may be roughened by dispersing a filler of several nm to several tens of nm in order to impart appropriate roughness. The method may be either internal addition in the base or coating on the surface. In addition to dispersing the filler, any method may be used for the purpose of imparting roughness to the surface.

Next, the magnetic layer 3 is formed on such a non-magnetic support 1. The magnetic layer 3 is composed of a metallic magnetic thin film, and is preferably formed to have a thickness of 100 nm or less by directly depositing a ferromagnetic metal material on the non-magnetic support 1. As the metallic magnetic material, any material can be used as long as it is used for a usual vapor deposition tape. For example, ferromagnetic metals such as Fe, Co and Ni,
Fe-Co, Co-Ni, Fe-Co-Ni, Fe-C
u, Co-Cu, Co-Au, Co-Pt, Mn-B
i, Mn-Al, Fe-Cr, Co-Cr, Ni-C
r, Fe-Co-Cr, Co-Ni-Cr, Fe-Co
A ferromagnetic alloy such as -Ni-Cr may be used. Magnetic layer 3
May be a single layer film or a multilayer film of these. Further, between the non-magnetic support 1 and the magnetic layer 3 or between the multi-layered films when the magnetic layer 3 is a multi-layered film, it is possible to improve the adhesive force between the layers and control the coercive force. An underlayer or an intermediate layer may be provided for this purpose. Further, for example, the vicinity of the surface of the magnetic layer 3 may be an oxide in order to improve corrosion resistance.

As means for forming such a magnetic layer 3, a vacuum evaporation method of heating and evaporating a ferromagnetic material in a vacuum atmosphere to deposit it on a non-magnetic support, or evaporation of a ferromagnetic metal material during discharge. The so-called PVD (Physical vapor depositio), such as an ion plating method to be performed, a sputtering method for knocking out atoms on the target surface with argon ions generated through a glow discharge in an atmosphere containing argon as a main component, etc.
n) According to technology.

Next, the protective film 5 is formed on the magnetic layer 3. The protective film 5 may be any one that is generally used as a protective film for ordinary metal magnetic thin films. By way of example, carbon, CrO2, Al ₂
0 ₃ , BN, Co oxide, MgO, SiO ₂ , Si ₃ O ₄ ,
SiN ₄ , SiC, SiN ₄ , SiO ₂ , ZrO ₂ , TiO
₂ , TiC and the like. The protective stem 5 may be a single layer film or a multilayer film made of these materials. The formation of the protective film 5 is performed by the PVD described above, for example.
Method or a CVD (chemical vapor deposition) method.

A back layer 7 is formed on the surface of the non-magnetic support 1 opposite to the surface on which the magnetic layer 3 is formed. The back layer 7 may be of any type as long as it is generally used as an ordinary back layer, for example, the protective film 5
A material similar to the material for forming is used as a single-layer film or a multilayer film, can be used in the same manner as the protective film, and may be formed by a coating method.

After the protective film 5 and the back layer 7 are formed as described above, the following steps are the steps characteristic of the present invention.

That is, after forming the protective film 5 and the back layer 7, first, the amination treatment of the surface of the protective film 5 is performed. This amination treatment is performed in a vacuum atmosphere, and any method such as a bombarding treatment with a gas containing a nitrogen atom or a CVD method using a gas containing a nitrogen atom as a raw material gas may be used. In the case of performing the bombarding process, nitrogen is bonded to the surface of the protective film 5 to perform the amination process, and the surface of the treated protective film 5 becomes the amination process surface 5a. Further, when the amination treatment is performed by the CVD method, a nitride film layer (amine layer) is formed on the protective film 5.
And the surface of this nitride film layer is amine or treated surface 5
a. Incidentally, as the nitride film layer formed by the CVD method, for example, aluminum nitride, chromium nitride, silicon nitride, titanium nitride, nitrides of nitrogen carbide or cobalt, nitrides of nickel, etc. have been conventionally used as protective films. If the material contains nitrogen, it can be used without particularly specifying the composition. Of these, DL
A material formed by mixing nitrogen with a raw material for obtaining a protective film made of C (diamond like carbon) can be preferably used as the nitride film layer.

After the surface of the protective film 5 is subjected to the amination treatment as described above, the amination treatment surface 5
The lubricant layer 9 is formed on the amination-treated surface 5a without exposing a to the air, that is, after the amination treatment in a vacuum atmosphere.

The lubricant layer 9 is formed by spraying the vaporized lubricant with the carrier gas onto the treated surface 5a in a vacuum atmosphere. At this time, the vaporized lubricant and carrier gas are supplied into the vacuum atmosphere while controlling the flow rates. As the carrier gas, an inert gas such as N ₂ or Ar is used.

The vaporization of the lubricant is carried out by heating the lubricant or by applying ultrasonic vibration to the lubricant liquefied by heating.

When the lubricant is vaporized by heating, the lubricant is heated to a temperature above the temperature at which the lubricant is sufficiently vaporized and below the temperature at which the lubricant is not decomposed, and the temperature is from 100 ° C. A temperature range of 350 ° C is desirable. Thereby, the lubricant layer 1 formed by spraying the lubricant
First, the lubricating effect can be exerted.

On the other hand, when the lubricant is vaporized by applying ultrasonic waves to the lubricant liquefied by heating, the lubricant is heated to a temperature range where the lubricant becomes liquid.

In addition, in any case where the lubricant is vaporized by any of the above-mentioned methods, it is necessary to heat the introducing pipe which serves as a path until the vaporized lubricant is introduced into the vacuum atmosphere. The heating temperature of the introduction pipe is equal to or higher than the temperature at which the vaporized lubricant is supplied into the vacuum atmosphere without being deposited in the pipe, and is equal to or lower than the temperature at which the vaporized lubricant is not decomposed in the introduction path. And 100 ℃ -350 ℃
Is desirable.

Further, the pressure of the vacuum atmosphere at the time of forming the lubricant layer 11 is not more than the pressure at which the boiling point of the lubricant does not exceed the decomposition point. The pressure of the vacuum atmosphere at this time is equal to or higher than the pressure capable of forming the lubricant layer 11 in which a predetermined amount of the lubricant is adsorbed per unit area. Therefore, the pressure of the vacuum atmosphere when forming the lubricant layer 11 is preferably set in the range of 10 Pa to 10 ⁻⁵ Pa.

Any lubricant can be used as the lubricant constituting the lubricant layer 11 as long as it is generally used as a tape-shaped magnetic recording medium. For example, a lubricant having a main skeleton of alkylamine, alkyl ester, fluorocarbon type, hydrocarbon containing a fluoroalkyl group, phosphoric acid ester, phosphorous acid ester or the like is used.

Of these, fluorine-based lubricants generally used when the magnetic layer 3 is composed of a metal magnetic thin film are particularly preferable. Specific examples of such a lubricant include synthetic products such as perfluoropolyether carboxylic acid ester,
Product name Fomblin Z-03, Z- manufactured by Ausimond
15, Z-DEAL, Z-25, Z-D0L, Z-DI
AC, Z-DISOC, AM-2001, Demnum S-20, S-65, S-100, S-2 manufactured by Daikin Industries, Ltd.
00, commercially available products such as fluorine-based grease represented by CRYDOX 240AC manufactured by DuPont and CRYDOX GPL, and those having a structure in which an alkyl group is added to perfluoropolyether are used.

Further, a lubricant layer 11 formed by deposition in a vacuum atmosphere as described above, the lubricant amount per unit area is formed in the range of 0.1mg / m ² ~100mg / m ² Is desirable. If it falls below that range, it is not possible to coat the surface of the lubricant evenly, so when exposed to the atmosphere during use, moisture in the atmosphere may be adsorbed on the surface from where it was not covered by the lubricant. Rust occurs. Also, if the value exceeds this range, the surface will be in an excessive amount of lubricant, which will cause sticking to the guide pins of the recording / reproducing system and the drum surface during recording / reproducing as well as sliding with the head. Due to the movement, the lubricant that cannot be completely adsorbed on the surface peels off and becomes a head deposit, which acts as a factor that deteriorates the durability. Therefore, the quantity of lubricant per unit area of the lubricant layer 11 is the above-mentioned range is essential, if ^{0.5mg / mm 2 ~20mg / mm 2} , still from corrosion protection, durability and running properties It is good.

As described above, the protective film 5 is formed on the one main surface of the non-magnetic support 1 with the magnetic layer 3 made of a metal magnetic thin film interposed therebetween.
And the lubricant layer 9 is further provided on the amination-treated surface 5a of the protective film 5, and the back layer 7 is provided on the other main surface of the non-magnetic support 1 to obtain a magnetic recording medium 10. .

According to the manufacturing method described above,
Since the lubricant layer 9 is formed in a vacuum atmosphere, the lubricant layer 9 can be formed without being affected by the adsorbed moisture on the film formation surface. Therefore, it becomes possible to obtain the magnetic recording medium 10 having the uniform lubricant layer 9 and having a high rust preventive effect.

Further, in the vacuum atmosphere, the lubricant layer 9
Therefore, the lubricant layer 9 can be formed without adhering foreign matter. Therefore, in recording / reproducing using the magnetic recording medium 10, the running stability of the head can be improved.

By forming the lubricant layer 9 on the amination-treated surface 5a, the lubricant layer 9 can be formed with good adhesion. At this time, in particular, by performing the amination treatment in a vacuum atmosphere and forming the lubricant layer 9 following the amination treatment, the adhesion of the lubricant layer 9 to the amination-treated surface can be further strengthened. it can. Therefore, the magnetic recording medium 10 having excellent durability
Can be obtained.

From the above, it is possible to realize a high-density and highly reliable magnetic recording medium on the assumption that an MR head is used. When the magnetic recording medium 10 is for a recording / reproducing system having an MR head, the magnetic layer 3
It is preferable that the energy product, which is the product of the residual magnetic flux density, the thickness, and the coercive force, is 75 G · cm · Oe or more, and the total thickness of the magnetic recording medium 10 is 5 μm or less.

A further advantage of the present invention, which is added to the above effects, is the use efficiency of the lubricant. That is, in the conventional coating film formation, the use efficiency of the lubricant dissolved in the residual liquid is poor and it is not possible to completely use it, but in the method of vaporizing and forming the film, it is deposited in the chamber or the introduction pipe. Everything can be used up except for what you do.

The method of manufacturing a magnetic recording medium according to the present invention is not limited to the above-mentioned procedure, and may be modified within the scope of the present invention, for example, the non-magnetic support 1 as necessary. There is no problem in forming an undercoat layer or forming a layer of a rust preventive agent or the like on top.

[0047]

EXAMPLES Next, specific examples of the present invention and comparative examples with respect to the examples, and the evaluation results thereof will be described. Here, evaluation samples (tape-shaped magnetic recording media) of the examples and comparative examples were produced with the amination treatment method and the lubricant layer forming conditions as factors, and the evaluation samples were evaluated.

The structure of each film forming apparatus used to manufacture the evaluation sample in each of the examples and comparative examples will be described below, and then FIG. 1 and each drawing will be described in the order of the manufacturing procedure of the evaluation sample, the evaluation method and the evaluation result. The description will be given with reference to it.

< Deposition Device> Deposition Device for Deposition of Magnetic Layer FIG. 2 is a block diagram of the deposition film device used when the magnetic layer 3 is formed on the non-magnetic support 1.

As shown in this figure, in the vapor deposition film forming apparatus, a watch shown in a figure is provided in a vacuum chamber 202 which is evacuated from the exhaust ports 201 provided at the head and the lower part to make a vacuum inside. A feed roll 203 that rotates at a constant speed in the rotating direction and a take-up roll 204 that rotates at a constant speed in the clockwise direction in the figure are provided, and the tape-shaped non-magnetic support 1 is provided from the feed roll 203 to the take-up roll 204. Are designed to run sequentially. In the middle part where the non-magnetic support 1 travels from the feed roll 203 to the take-up roll 204 side,
A cooling can 206 having a diameter larger than that of each roll 203, 204 is provided. This cooling can 206
Is provided so as to pull out the non-magnetic support 1 downward in the figure, and is configured to rotate at a constant speed in the clockwise direction in the figure.
The feed roll 203, the take-up roll 204, and the cooling can 206 each have a cylindrical shape having a length substantially the same as the width of the non-magnetic support 1, and the cooling can 206 is internally illustrated. Not equipped with a cooling device,
The nonmagnetic support 1 can be prevented from being deformed due to a temperature rise. Therefore, the non-magnetic support 1 is sequentially fed from the feed roll 203, further passes through the peripheral surface of the cooling can 206, and is wound up by the winding roll 204. The guide roll 20 is provided between the feed roll 203 and the cooling can 206 and between the cooling can 206 and the take-up roll 204.
7, 208 are provided, the feeding roll 203 to the cooling can 206 and the cooling can 206 to the ticket collecting roll 20.
A predetermined tension is applied to the non-magnetic support 1 that travels over 4, so that the non-magnetic support 1 runs smoothly.

Further, in the vacuum chamber 202, the cooling can 2
The crucible 209 is provided below the 06.
A magnetic metal material 210 is filled in the inside 9. The crucible 209 has substantially the same width as the width of the cooling can 206 in the longitudinal direction (depth direction in the drawing). On the other hand, the vacuum chamber 2
An electron gun 211 for heating and evaporating the metallic magnetic material 210 filled in the crucible 209 is provided on the side wall of 02.
Is attached. This electron gun 211 is the electron gun 2
The electron beam X emitted from 11 is disposed at a position where the metallic magnetic material 210 in the crucible 209 is irradiated. Then, the metallic magnetic material 2 evaporated by the irradiation of the electron beam X
10 is deposited and formed as a magnetic layer 3 (see FIG. 1) on the non-magnetic support 1 that runs at a constant speed on the peripheral surface of the cooling can 206.

The shutter 2 is provided between the cooling can 206 and the crucible 209 and near the cooling can 206.
12 are provided. The shutter 212 is formed so as to cover a predetermined region of the non-magnetic support 1 that runs at a constant speed on the peripheral surface of the cooling can 206, and the metal magnetic material 210 evaporated from the crucible 209 with respect to the non-magnetic support 1. It is designed to be obliquely deposited within a predetermined angle range. further,
During such vapor deposition, oxygen gas O ₂ is supplied to the surface of the non-magnetic support 1 through an oxygen gas inlet 214 that penetrates the sidewall of the vacuum chamber 202, and magnetic properties, durability and weather resistance are obtained. Of the magnetic layer 3 is formed.

CVD Device for Forming Protective Film FIG. 3 is a block diagram of a CVD device used for forming the protective film 5 (carbon protective film) on the non-magnetic support 1 via the magnetic layer 3. .

As shown in this figure, the CVD apparatus rotates in a counterclockwise direction at a constant speed in a vacuum chamber 302 whose inside is made into a high vacuum state by an evacuation system 301 provided at the head. And a winding roll 304 that rotates at a constant speed in the counterclockwise direction in the drawing,
The non-magnetic support 1 having the magnetic layer 3 formed thereon is sequentially run from the feed roll 303 to the take-up roll 304. In the middle part where the non-magnetic support 1 travels from the feed roll 303 to the take-up roll 304 side,
A counter electrode can 306 having a diameter larger than that of each of the rolls 303 and 304 is provided. The counter electrode can 306 is provided so as to pull out the non-magnetic support 1 downward in the figure, and is configured to rotate at a constant speed in the clockwise direction in the figure. The feed roll 303 and the take-up roll 30
4 and the counter electrode can 306 each have a cylindrical shape having a length substantially the same as the width of the non-magnetic support 1. Therefore, the non-magnetic support 1 is provided with the feed roll 303.
It is configured to be sequentially sent out from the above, passes through the peripheral surface of the counter electrode can 306, and is wound up by the winding roll 304. In addition, between the feed roll 303 and the counter electrode can 306, and between the counter electrode can 30.
Guide rolls 307 and 308 are respectively arranged between the roll 6 and the take-up roll 304, and the feed roll 303 to the counter electrode can 306 and the counter electrode can 306.
A predetermined tension is applied to the non-magnetic support 1 traveling from the winding roll 304 to the non-magnetic support 1 so that the non-magnetic support 1 travels smoothly.

In the vacuum chamber 302, a reaction tube 309 made of borosilicate glass, plastic or the like is provided below the counter electrode can 306. This reaction tube 3
09 has one end penetrating the bottom of the vacuum chamber 302, and the film forming gas is introduced into the reaction tube 309 from this end. In addition, an electrode 310 made of a metal mesh or the like is attached to the middle of the reaction tube 309. This electrode 310 is a DC
It is connected to a power supply 311 and a voltage of 500 to 2000 V is applied.

In the CVD apparatus having such a structure, the electrode 3
When a voltage is applied to 10, glow discharge occurs between the electrode 310 and the counter electrode can 306. And
The film-forming gas introduced into the reaction tube 309 is decomposed by the generated glow discharge and deposited on the non-magnetic support 1, whereby the protective film 5 is formed.

Sputter Film Forming Apparatus for Forming Back Layer FIG. 4 shows a configuration diagram of a sputter film forming apparatus used for forming the back layer 7 on the non-magnetic support 1.

The sputter film forming apparatus shown in this figure is a magnetron sputter apparatus, and the vacuum pump 401 connected via a valve 401a allows the sputtering film forming apparatus to reach, for example, about 10 ^-4 P.
A vacuum chamber 402 that is depressurized to about a is provided. In the vacuum chamber 402, like the above-described CVD device,
A feed roll 403, a take-up roll 404, a counter electrode can 406, and guide rolls 407 and 408 are provided. The non-magnetic support 1 is sequentially fed from the feed roll 403, and further the circumference of the counter electrode can 406 is provided. It passes through the surface, is wound up by the winding roll 404, and runs smoothly. Incidentally, the counter electrode can 40
A cooling device (not shown) is provided inside 6 so as to suppress deformation of the non-magnetic support 1 due to temperature rise.

Further, in the vacuum chamber 402, a target 407 is arranged opposite to the counter electrode can 406. The target 407 is a material of the back layer 7, and carbon, for example, is used. The target 407 is supported by a backing plate 408 that constitutes a cathode electrode. Then, on the back side of the backing plate 408, a magnet 40 that forms a magnetic field is formed.
9 are provided. Then, the counter electrode can 406
Between the target and the target 408, the supply end of the gas introduction pipe 411 provided to penetrate the side wall of the vacuum chamber 402 is arranged.

In this sputtering film forming apparatus, the vacuum pump 4
After decompressing the inside of the vacuum chamber 402 to about 10 ⁻⁴ Pa by 01, the exhaust rate is reduced by narrowing the angle of the valve 403, and at the same time Ar gas is introduced from the gas introduction pipe 411, whereby the vacuum chamber 402 The degree of vacuum inside is set to about 0.8 Pa, for example. Then, the counter electrode can 406
Is applied as an anode and a backing plate 408 is used as a cathode, and a voltage of about 3000 V is applied to keep a current of about 1.4 A flowing. Then, by applying this voltage, Ar gas is turned into plasma, and the ionized ions collide with the target 407, so that the target 40
7 atoms are kicked out. At this time, since the magnet 409 is arranged on the back side of the backing plate 408 and a magnetic field is formed in the vicinity of the target 407,
The ionized ions are concentrated near the target 407. Then, the atoms ejected from the target 407 adhere to the nonmagnetic support 1 to form the pack layer 7.

Vaporization Film Forming Device for Forming Lubricant Layer In FIG. 5, the surface of the protective film 5 formed on the non-magnetic support 1 was subjected to an amination treatment, and was used for forming a lubricant layer 9. The block diagram of a vaporization film-forming apparatus is shown.

This vapor deposition film forming apparatus is, like the CVD film forming apparatus described with reference to FIG. 3, a vacuum chamber 502 provided with a vacuum pump 501 via a valve 501a, and is provided in this vacuum chamber 502. A feed roll 503, a winding roll 504, a counter electrode can 506, and guide rolls 507 and 508 are provided.

In the vacuum chamber 502, a discharge tube 509 is provided so as to cover the traveling path of the non-magnetic support 1 between the guide roll 507 and the counter electrode can 506. A vacuum chamber 502 is provided on the side wall of the discharge tube 509.
A gas introduction pipe 510 penetrating the wall surface of is connected, and nitrogen gas (N ₂ ) is supplied from the gas introduction pipe 510. An electrode 511 made of metal mesh or the like is attached to the inner peripheral wall of the discharge tube 509. The electrode 511 is connected to a DC power supply 512 arranged outside and a voltage is applied.

Further, in the vacuum chamber 502, a reaction tube 513 made of borosilicate glass, plastic or the like is provided with one end side opened to the counter electrode can 506 side. The other end of the reaction tube 513 penetrates the side wall of the vacuum chamber 502, and the film forming gas is introduced into the reaction tube 513 from this end. Also,
An electrode 514 made of a metal mesh or the like is attached to the middle of the reaction tube 513. This electrode 514
Is connected to a DC power source 515 arranged outside and a voltage is applied.

Furthermore, in the vacuum chamber 502, on the downstream side of the reaction tube 513 in the traveling direction of the non-magnetic support 1, a sprayer 516 for facing the counter electrode can 506 and spraying a lubricant is provided. Is provided. A gas introduction pipe 517 is connected to the atomizer 516, and a heater 518 is provided around the gas introduction pipe 517. The gas introducing pipe 517 penetrates the bottom of the vacuum chamber 502 and is connected to the vaporizer 519.
19 is a liquid supply pipe 520 and a carrier gas supply pipe 521.
And are connected. Then, mass flow controllers 522, 523, and 524 are arranged in the gas supply pipe 517, the liquid supply pipe 520, and the carrier gas supply pipe 521, respectively, and the flow rates in the respective pipes are controlled.

The end of the liquid supply pipe 520 is inserted into the lubricant L liquefied by heating in the storage tank 525, and the lubricant L is vaporized by the vaporizer 525 by the gas pressure supplied into the storage tank 525. Is configured to be sent to. In addition, the sprayer 516 and the counter electrode can 506.
A shutter 526 for controlling spraying from the sprayer 516 is provided between the and.

In such a vapor deposition film forming apparatus, the electrode 511 is used.
The nitrogen gas supplied into the discharge tube 509 is ionized by applying a voltage to the surface of the non-magnetic support 1 (protective film 7) is bombarded by the nitrogen ions, and the surface of the protective film 7 is aminated. It is processed. Further, when a voltage is applied to the electrode 514, glow discharge occurs between the electrode 514 and the counter electrode can 506. Then, the film-forming gas introduced into the reaction tube 513 is decomposed by this glow discharge, and the amination-treated surface 5a on the non-magnetic support 1 is decomposed.
Be attached to. Therefore, by supplying a gas containing nitrogen as a film forming gas or a gas conventionally used for forming a protective film, a nitride film is formed on the amination-treated surface 5a, and finally a film is formed. This nitride film surface becomes the amination-treated surface 5a.

When no voltage is applied to the electrode 514 and only the electrode 511 is applied, the amination treatment is performed only by the bomber and the treatment. On the other hand, the electrode 511
If no voltage is applied to the electrode 514 but only to the electrode 514, the amination treatment is performed only by forming the nitride film.

Further, the lubricant L liquefied from the storage tank 525 is supplied to the vaporizer 519 to vaporize the lubricant L, and the vaporized lubricant L is supplied to the carrier gas supply pipe 52.
Gas introduction pipe 517 together with the carrier gas supplied from No. 1
Is introduced into the vacuum chamber 502 from the above and is sprayed onto the non-magnetic support 1 (amination-treated surface 5a) by the sprayer 516 to form the lubricant layer 9.

<Manufacturing Procedure of Magnetic Recording Medium> Next, a manufacturing procedure of each magnetic recording medium which is an evaluation sample of each embodiment and comparative example will be described.

First, as the non-magnetic support 1, polyethylene naphthalate (4.5 μm thick, 150 mm wide) was prepared.

Then, a ferromagnetic metal thin film made of a Co single layer film was deposited as the magnetic layer 3 on the non-magnetic support substrate 1 by using the deposition film forming apparatus described with reference to FIG. The conditions for vapor deposition of the magnetic layer 3 are as follows. Ingot: Co 100 wt% Electron beam incident angle: 45 ° to 10 ° Introduced gas: Oxygen gas Oxygen introduced amount: 2.8 × 10 ⁻⁶ m ³ / sec Vacuum degree during deposition: 2 × 10 ⁻² Pa Film thickness of magnetic layer : 60 nm

Next, the carbon (diamond-like carbon) protective layer 5 was formed on the non-magnetic support 1 via the magnetic layer 3 by using the CVD apparatus described with reference to FIG. C
The VD film forming conditions are as follows. Reaction gas: Toluene Reaction gas pressure: 10 Pa Electric power introduced: DCl. 5 kV carbon protective layer film thickness: 10 nm

After that, the back layer 7 made of carbon was formed on the back surface side of the non-magnetic support 1 on which the magnetic layer 3 and the protective film 5 were formed, using the sputtering film forming apparatus described with reference to FIG. . The sputtering film formation conditions are as follows. Target: Carbon Sputter gas: Ar (Argon)

After that, the surface of the protective film 5 is subjected to an amination treatment by using the vaporization film forming apparatus described with reference to FIG.
Further, a lubricant layer 9 was formed on the amination-treated surface. The lubricant L includes perfluoropolyether (registered trademark name;
FONBLIN) Z-DOL was used. The amination treatment was carried out in two ways, that is, only the nitrogen bombardment treatment was performed, and that the nitride film was formed by the CVD method using nitrogen gas and ethylene gas as reaction gases. Table 1 below shows the processing conditions of a series of vaporization film-forming processes including the amination process.

[0076]

[Table 1]

As described above, the raw tape having the magnetic layer 3, the protective layer 5, the back layer 7 and the lubricant layer 9 formed on the non-magnetic supporting substrate 1 was cut into a width of 6.35 mm. A tape-shaped magnetic recording medium 10 was produced. The total thickness of each magnetic recording medium 10 was 5 μm or less.

<Evaluation Method and Evaluation Results> With respect to the magnetic recording media 10 of Examples 1 to 10 and Comparative Examples 1 to 9 (that is, evaluation samples) obtained as described above, the coverage of the lubricant and the magnetization deterioration rate. The dynamic friction coefficient and durability were measured.

Lubricant coverage SPM (Scanning Probe Microsc) manufactured by SHIMADZU
ope) 9500-J2 was used. In the contact mode, the meniscus force acting between the tip and the sample surface at the moment when the tip leaves the sample is defined as the adsorption force, and it takes 30 minutes in the glove box to ignore the influence of surface adsorbed water in the measurement environment. After the vacuum was drawn, in-plane mapping of the adsorption force was performed in the vacuum, and the variation in the value (standard deviation of the adsorption force) is shown in Table 1 as the coverage. Therefore, the smaller the coverage rate in Table 1, the more uniformly adsorbed, and the larger the coverage rate, the lower the uniformity.

Magnetization deterioration rate 1 ppm in SO ₂ gas, 50 ° C., 80% RH atmosphere
It was stored for 0 hours and evaluated by the magnetization deterioration rate before and after that. If this value is within 5%, it can be used.

Dynamic friction coefficient Sliding 1 when the evaluation sample was slid 100 times at an included angle of 90 ° with respect to a SUS guide having a diameter of 2.0 mm.
The dynamic friction coefficient at the 100th time and the dynamic friction coefficient at the 100th time were measured.

Durability A commercially available Sony digital video (VX-1000) equipped with an MR head was modified and used as a deck, and the shuttle durability was measured by running while monitoring the output. At this time, the entire tape length of the evaluation sample was repeatedly run (100 pass) at room temperature, the initial output was A, the lowest output during 100 pass running was B, and the level-down value was -20 x log (A / B). [DB]
Defined as The level down value is 0 to -2.
When the level is 0 [dB], the durability is extremely high (○), and when the level down value is −2.1 to −3.9 [dB], the durability is slightly high (Δ), the level down value. Is -4.0
Table 1 shows that the durability is low (x) when it is less than [dB].

As is clear from the above results, Example 1
-In Example 10 , the formation of the lubricant layer 9 was performed in a vacuum atmosphere following the amination treatment in a vacuum atmosphere, and the amount of lubricant was 0.1 mg / m < ² > -100 mg.
/ M ² or less, the variation in the coverage of the lubricant layer 9 was as small as 0.1 or less, and it was confirmed that the lubricant layer 9 was uniformly formed. It was also confirmed that the magnetization deterioration rate was suppressed to within the allowable range of 5% or less, the dynamic friction coefficient was small, and the durability was good.

On the other hand, in Comparative Example 1 in which oxygen gas (O ₂ ) was used as the carrier gas during the vacuum film formation of the lubricant layer 9, oxygen and the lubricant reacted during film formation, and Could not maintain the properties of the lubricant in.
For this reason, the rust prevention effect could not be obtained, the magnetization deterioration rate was as high as 14%, and the shuttle durability was also low.

Further, in Comparative Example 2 in which the amination treatment was not performed as the pretreatment for the vacuum film formation of the lubricant layer 9, the adhesiveness between the lubricant 9 and the base was not obtained, and the durability was low and the magnetization The fruit cracking rate was as high as 8%.

Further, the lubricant layer 9 is formed in a vacuum atmosphere.
At that time, the pressure of the film forming atmosphere was as high as 15 Pa.Comparative Example 3
, The amount of lubricant per unit area is 0.04 mg
/ M ²And a sufficient amount of lubricant layer 9 can be formed.
Not possible, both the magnetization deterioration rate and the dynamic friction coefficient are high, and the shuttle resistance is high.
His longevity was low.

In Comparative Example 4 in which the heating temperature of the lubricant when forming the lubricant layer 9 was as low as 90 ° C., the lubricant could not be vaporized and the lubricant layer 9 could be formed. There wasn't.

Further, in Comparative Example 5 in which the heating temperature of the lubricant when forming the lubricant layer 9 was as high as 360 ° C., the heating temperature was too high and decomposition of the lubricant occurred, so that the lubricant layer 9 The properties of the lubricant could not be maintained, the rate of magnetic deterioration and the coefficient of dynamic friction could not be suppressed, and the shuttle durability was not sufficient.

Further, in Comparative Example 6 in which the heating temperature of the pipe, which serves as a path for introducing the vaporized lubricant into the film-forming atmosphere, was as low as 95 ° C., the lubricant was precipitated in the pipe, and The agent layer 9 could not be formed.

In Comparative Example 7 in which the pipe heating temperature was as high as 360 ° C., the heating temperature was too high and the lubricant decomposed, and the characteristics of the lubricant in the lubricant layer 9 could not be maintained. As a result, the magnetization deterioration rate and the dynamic friction coefficient could not be suppressed, and the shuttle durability was not sufficient.

[0091] The comparison pressure in the deposition atmosphere during the formation of the lubricant layer 9 in a vacuum atmosphere was as low as 5 × 10 ^-6 Pa
In Example 8 , the amount of lubricant per unit area is 0.02
Since the lubricant layer 9 was as small as mg / m ² , the lubricant layer 9 could not be formed sufficiently, and the magnetization deterioration rate and the dynamic friction coefficient were both high, and the shuttle durability was also low.

Furthermore, in Comparative Example 9 in which the lubricant layer 9 was formed by coating, the variation in the coverage was as large as 0.28, which made it impossible to obtain the rust preventive effect and the magnetization deterioration rate was 22%. It was great. The dynamic friction coefficient was also large.

From the above results, among the forming conditions of the lubricant layer 9, the vaporization temperature of the lubricant and the pipe temperature which becomes a route when introducing the vaporized lubricant into the film forming atmosphere,
Furthermore, a suitable range of the pressure (vacuum degree) in the film forming atmosphere is set as follows.

That is, the upper limit of the vaporization temperature of the lubricant is preferably 350 ° C. from the comparison between Example 1 and Comparative Example 5. Furthermore, the lower limit of the vaporization temperature of the lubricant is set in Example 4 and Comparative Example 4
From the comparison with, 100 ° C. is preferable. In this way, by setting the vaporization temperature of the lubricant within the range of 100 ° C. to 350 ° C., it becomes possible to vaporize the lubricant without decomposing it and form the lubricant layer.

From the comparison between Example 3 and Comparative Example 7, the upper limit of the pipe heating temperature is preferably 350 ° C. Furthermore, the lower limit of the pipe heating temperature is preferably 100 ° C. from the pipe heating temperatures of Example 7 and Comparative Example 6. Thus, by setting the vaporization temperature of the pipe heating temperature in the range of 100 ° C. to 350 ° C., the lubricant is supplied into the film forming atmosphere without decomposing in the pipe and precipitating in the pipe. It becomes possible to form a lubricant layer.

From the comparison between Example 8 and Comparative Example 3, the upper limit of the pressure of the film forming atmosphere when the lubricant layer is formed is
10 Pa is preferable. Further, from the comparison between Example 10 and Comparative Example 8, the lower limit of the pressure of the film forming atmosphere is preferably 10 ⁻⁵ Pa. In this way, the pressure of the film forming atmosphere is 10 Pa to 10 Pa.
^By setting the pressure in the range of ^-5 Pa, it is possible to form a lubricant layer to which a sufficient amount of lubricant has been supplied, and to obtain a lubricant layer having a uniform coverage of 0.1 or less. You can

The amount of lubricant per unit area of the lubricant layer was 0.1 mg / m ² to 1 from Example 4 and Example 5.
00 mg / m ² is preferred. As a more preferable range of the amount of lubricant, the upper limit is 20 mg / m ^{2 of} Example 9 from the value of shuttle durability, and the lower limit is 0.50 mg / m ^{2 of} Example 2 from the value of dynamic friction coefficient.

[0098]

As described above, according to the method of manufacturing a magnetic recording medium of the present invention, since the lubricant layer is formed in a vacuum atmosphere, it is affected by the adsorbed moisture on the film-forming surface. It is possible to obtain a lubricant layer that is uniform and has no foreign matter attached. As a result, under high temperature and high humidity,
Further, it is possible to obtain a magnetic recording medium having an excellent rust preventive effect in a corrosive atmosphere and excellent running stability. Also,
By performing the amination treatment in the same atmosphere as the pretreatment for the formation of the lubricant layer, it is possible to reliably increase the surface adsorption amount / adsorption force of the lubricant, and the lubricant layer peels off during repeated running. Therefore, a high density magnetic recording medium having excellent durability and reliability can be obtained. As a result, it is possible to realize a high-density magnetic recording medium on the assumption that the MR head is used.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a magnetic recording medium obtained by the present invention.

FIG. 2 is a schematic diagram showing a vapor deposition apparatus used when forming a magnetic layer.

FIG. 3 is a schematic diagram showing a CVD apparatus used when forming a protective film.

FIG. 4 is a schematic view showing a sputtering apparatus used when forming a back layer.

FIG. 5 is a schematic diagram showing a vaporization film forming apparatus used when forming a lubricant layer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Nonmagnetic support, 3 ... Magnetic layer, 5 ... Protective film, 5a ... Amination-treated surface, 9 ... Lubricant layer, 10 ... Magnetic recording medium

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Seiichi Onodera             6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Soni             -Inside the corporation F term (reference) 5D006 AA01 AA05 AA06 EA03 FA01                       FA02 FA05                 5D112 AA07 AA22 BC06 FA02 FA04                       FA09 FB08 FB12

Claims (5)

[Claims] 1. A method of manufacturing a magnetic recording medium, wherein a protective film is formed on a non-magnetic support via a magnetic layer, and a lubricant layer is formed on the protective film. A method of manufacturing a magnetic recording medium, which is performed by spraying a lubricant vaporized in an atmosphere together with a carrier gas. 2. The method for manufacturing a magnetic recording medium according to claim 1, wherein the lubricant imparts ultrasonic vibration to the lubricant liquefied by heating or is vaporized by heating. Recording medium manufacturing method. 3. The method of manufacturing a magnetic recording medium according to claim 1, wherein the lubricant layer has an amount of lubricant of 0.1 m per unit area.
method of manufacturing a magnetic recording medium, characterized in that it is formed in a range of ^{g / m 2 ~100mg / m 2} . 4. The method of manufacturing a magnetic recording medium according to claim 1, wherein the lubricant layer is formed on an amination-treated surface. 5. The method of manufacturing a magnetic recording medium according to claim 4, wherein the amination treatment is performed in a vacuum atmosphere and the lubricant layer is formed by exposing the amination-treated surface to the atmosphere. A method for producing a magnetic recording medium, characterized in that the amination treatment is continuously performed.