JPH10124867A - Apparatus for production of magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the thermal conduction of a vapor flow diffusion control means in the vacuum deposition device which produces magnetic recording media by vapor deposition and has the vapor flow diffusion control means. SOLUTION: The vapor flow diffusion control means 15 is composed of plural layers constitution consisting of inside wall parts 15a, intermediate parts 15b and outer peripheral parts 15c laminated successively form the inner side toward the outer side. The means is provided with spacings between the inside wall parts 15a and the intermediate parts 15b into which packing materials 30 are packed. As a result, even if the spacings to prevent crack are opened between the inside wall parts 15a and the intermediate parts 15b, the heat of the inside wall parts 15a is transmitted via the packing materials 30 to the intermediate parts 15b and, therefore, the heat conduction between the inside wall parts 15a and the intermediate parts 15b is well effected and the vapor deposition efficiency in improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a magnetic recording medium, and more particularly, to a method of heating and melting a metal material, evaporating the metal material, and depositing the vapor stream on a flexible substrate such as a base film. The present invention relates to an apparatus for manufacturing a magnetic recording medium in which a magnetic recording layer is formed by performing the method.

[0002]

2. Description of the Related Art Conventionally, as a magnetic recording medium, γ-Fe
₂ O ₃ , Co-doped Fe ₃ O ₄ , γ-Fe ₂ O ₃
Magnetic material as a berthollide compound of Fe ₃ O _4, berthollide compound doped with Co, from CrO _3, Ba oxide magnetic material such as ferrite, or Fe, Co, an alloy magnetic material mainly composed of Ni or the like Particles are dispersed and mixed together with additives in an organic binder such as a vinyl chloride-vinyl acetate copolymer, a styrene-butadiene copolymer, an epoxy resin, a polyurethane resin, and the dispersion mixture is mixed with a polyester such as polyethylene terephthalate (PET). 2. Description of the Related Art A so-called coating type magnetic tape is widely known, which is manufactured by coating a base film (substrate) made of polyolefin such as polypropylene or polypropylene and then drying the base film.

On the other hand, in recent years, the demand for higher recording density has become stronger, and the density of the magnetic material in the magnetic layer of the magnetic recording medium has been increased, the coercive force has been improved, the magnetic layer has been made thinner, or the frequency characteristics have been shortened. Improvements such as shifting to the wavelength side have been made. However, in the coating type tape, since the binder remains in the magnetic layer, it is difficult to satisfy the above-described conditions required for high-density recording.

Accordingly, attention has been paid to a method of manufacturing a magnetic recording medium by a vapor deposition method such as vacuum deposition, sputtering, or ion plating, or a plating method such as electroplating or electroless plating, and various proposals have been made. According to these methods, the magnetic layer can be formed by depositing and growing a magnetic material directly on a substrate without using a binder, so that the packing density of the magnetic material in the magnetic layer is increased, and Can also be made thinner.

In addition, these vapor deposition methods and the like make it easy to control the adjustment of the film thickness formed on the base film, adjust the coating solution of the magnetic layer in the manufacturing process of the coating type tape, and perform drying after coating. This has practically useful advantages such as eliminating the need for processing steps associated with the formation of a magnetic layer.

In particular, the vapor deposition method has the advantages that the waste liquid treatment required in the plating method is unnecessary and that the growth rate of the deposited magnetic film is high.
A magnetic tape using a magnetic layer formed on a base film by such a vapor deposition method as a recording layer has a much higher reproduction output and a shorter frequency characteristic of a recording signal than a conventional coating type magnetic tape. It is useful as a high-density magnetic recording medium, for example, it is improved on the wavelength side.

The production of the magnetic recording medium by the vapor deposition method can be performed in detail by, for example, a vacuum vapor deposition apparatus 1 shown in FIG. As shown in FIG. 3, the vacuum evaporation apparatus 1 has a cylindrical shape and a non-magnetic material such as a polyester film, a polyamide film, a polyimide film, etc. A cooling can 4 for winding a long base film 3 made of a material in the longitudinal direction is provided. The cooling can 4 is rotated in the direction of arrow Y to send out the base film 3 and send the base film 3 from the shaft 5 side to the winding shaft 6 side. Conveyed to.

The inside of the vacuum chamber 2 is wound by a partition plate 7 into a winding chamber 8 for feeding and winding the base film 3.
And a deposition chamber 9 for depositing a magnetic material on the base film 3. In the vapor deposition chamber 9, Co, CoNi alloy, CoCr alloy, CoC
An evaporation source 11 provided with a magnetic material 10 such as an rNi alloy is provided, and the magnetic material 10 is heated and evaporated by heating means 12 such as electron gun heating, resistance heating, and high-frequency induction heating. The particles of the magnetic material 10 as a vapor flow that evaporate and rise (referred to as magnetic particles or evaporating particles) are formed as a magnetic layer on the surface of the base film 3 that is conveyed in the direction of arrow Y with the rotation of the cooling can 4. Deposit continuously.

Here, in order to efficiently deposit the evaporated magnetic material particles on the substrate to increase the vapor deposition efficiency, it is sufficient to prevent the evaporated particles from diffusing widely. According to the technology disclosed in Japanese Patent Application Laid-Open No. 2-56730, a cylindrical shape is provided between the evaporation source and the cooling can so that the peripheral wall surrounds a portion through which the evaporated particles pass. What is necessary is just to provide the vapor flow diffusion control means (sometimes simply called vapor diffusion control means) 15. The vapor diffusion control means 15 has an inner wall surface for re-evaporating or collecting and collecting the evaporated particles of the magnetic material 10 attached to the inner wall surface, or for combining re-evaporation and collecting and collecting. Means for heating or cooling the temperature.

When such a cylindrical vapor diffusion control means 15 is provided, it is difficult to use an electron gun heating means generally used as a heating means. In other words, in this case, it is necessary to secure the trajectory of the electron beam from the electron gun to the magnetic material 10 in the evaporation source 11.
This is because, if the vapor diffusion control means 15 is provided above 11, it is difficult to secure a passage trajectory of the electron beam. Therefore, high frequency induction heating means is usually used as the heating means.

On the other hand, the above-mentioned vapor diffusion control means prevents the diffusion of the vapor flow by its inner wall surface. On the other hand, the vapor flow contacts the inner wall surface, and the evaporated magnetic material adheres to the inner wall surface. There is a risk of solidification. When the magnetic material adheres and solidifies on the inner wall surface, the vapor flow distribution becomes different from the intended vapor flow distribution, and maintenance such as a recovery operation of the deposited magnetic material is required. Therefore, in the above method, a heating source is added to the vapor diffusion control means, the inner wall surface of this means is set to a temperature equal to or higher than the boiling point of the magnetic material, and the magnetic material which collides with the inner wall surface of the vapor diffusion control means and adheres to the inner wall surface Are re-evaporated so that they can merge with other vapor streams.

However, since the scattering direction of the magnetic material particles re-evaporated from the inner wall surface of the vapor diffusion control means is different from the scattering direction of the other magnetic material particles, the originally intended steam flow distribution cannot be obtained and the deposition efficiency is reduced. Was likely to be caused. On the other hand, a manufacturing process of a magnetic recording medium for forming a magnetic thin film on a flexible substrate as used in the present invention is generally called oblique deposition.

The purpose of the oblique deposition is to grow a magnetic crystal deposited on a flexible substrate at an oblique angle with respect to the vertical direction of the flexible substrate, and to improve magnetic properties such as coercive force. The point is to improve. Therefore, the re-evaporated magnetic material particles adhering to the flexible substrate at an arbitrary angle hinder stable crystal growth in oblique vapor deposition, and may cause instability of magnetic characteristics. .

Therefore, by adjusting the temperature of the inner wall surface of the vapor diffusion control means to a temperature higher than the melting point of the magnetic material constituting the steam flow and lower than the boiling point, the magnetic material adhering to the inner wall surface of the vapor diffusion control means is adjusted. Particles are liquefied without being re-evaporated and descend along the inner wall surface, whereby the vapor flow from the upper opening of the vapor diffusion control means contains particles of the magnetic material re-evaporated from the inner wall surface of the vapor diffusion control means. A method for manufacturing a magnetic recording medium has been proposed in which a high vapor deposition efficiency is maintained without disturbing the vapor flow distribution by the vapor flow of the re-evaporated magnetic material (see Japanese Patent Application Laid-Open No. HEI 9-64572). 2-56730).

On the other hand, in such a magnetic recording medium manufacturing apparatus, the vapor diffusion control means has a two-layer structure of an inner wall portion and an outer peripheral portion provided outside the inner wall portion, or an inner wall portion, an intermediate portion and an outer peripheral portion. A three-layer structure is known. For example, Japanese Patent Application Laid-Open No. 2-56730 discloses that an inner wall portion is formed of a ceramic material, an outer intermediate portion is formed of a heat conductive medium such as carbon fiber, and an outer peripheral portion of the outer wall portion is cooled. A steam diffusion control means having a three-layer structure constituted by a water-cooled cylinder as a cooling means is disclosed. There is also known an apparatus in which a heating means is provided instead of the cooling means to heat the inner wall to a desired temperature. Since the vapor diffusion control means has a two-layer or three-layer structure, the heat of the inner wall can be transmitted to the cooling means satisfactorily or the inner wall can be satisfactorily heated. It is said that the control of the magnetic material becomes easy, thereby preventing the re-evaporation of the magnetic material attached to the inner wall portion and improving the vapor deposition efficiency.

[0016]

In the case where the above-mentioned vapor flow diffusion control means is composed of a plurality of layers, each layer may be cracked when expanded between layers due to thermal expansion. Needs to be provided.
However, if a gap is provided between the layers, the gap functions as a heat insulating material, and the effect of releasing the heat of the layer inside the vapor flow diffusion control means to the outside is reduced.

On the other hand, the inner layer of the vapor flow diffusion control means is usually made of a ceramic having high heat resistance in many cases. A cylindrical member made of this ceramic is mixed with particles having an appropriate particle size, and then gradually put into a metal mold and solidified, or molded by applying pressure with a press machine, and then removed from the mold It is formed by firing at a temperature of 1400C to 1600C. This baked product is not always uniform in dimensional accuracy, but has some distortion and dimensional deviation. The layers formed outside the ceramic layer are usually graphitic carbon, BN, metal, etc., which are processed with a substantially constant processing accuracy, so that they hardly cause distortion or dimensional deviation. It is. Therefore, when the ceramic layer and the outer layer are fitted, the size of the ceramic layer changes, so that the size of the gap varies depending on the combination of the layers, and heat transfer from the inner layer to the outer layer varies depending on the product. The rate changes, causing a problem in reproducibility when creating the vapor flow diffusion control means.

In view of the above circumstances, the present invention sets the heat transfer coefficient from the inner layer to the outer layer of the steam flow diffusion control means to be always constant, and sets the heat transfer coefficient from the inner layer to the outer layer of the steam flow diffusion control means. It is an object of the present invention to provide a magnetic recording medium manufacturing apparatus capable of efficiently releasing heat toward a layer.

[0019]

According to the present invention, there is provided an apparatus for manufacturing a magnetic recording medium, comprising: transport means for transporting a long flexible substrate in a vacuum atmosphere; An evaporation source made of a magnetic material, an evaporation unit for heating and evaporating the evaporation source, and a diffusion direction of the vapor flow heated and evaporated by the evaporation unit, disposed between the evaporation unit and the flexible substrate. A magnetic recording medium for forming a magnetic thin film on the flexible substrate, comprising: a vapor flow diffusion control means for regulating and controlling; and an incident angle regulating means for regulating an incident angle of the vapor flow to the flexible substrate. Wherein the vapor flow diffusion control means comprises a plurality of cylindrical layers stacked from the inside to the outside of the means, and at least the n-th layer from the innermost and the (n + 1) -th layer among the respective layers. Layer (n:
A natural number), and the gap has a thermal conductivity of 0.
This is achieved by a magnetic recording medium manufacturing apparatus characterized by being filled with a material of 03 kcal / mh ° C to 500 kcal / mh ° C.

The heat transfer coefficient is more desirably 10 to 400 kca
l / mh ° C, most preferably 40 to 350 kcal / mh ° C.

When the heat transfer coefficient is less than 0.03 kcal / mh ° C.,
The filling material functions as a heat insulating material, and is 500 kcal / mh ° C.
This is because if the ratio exceeds, the filling material is liable to deteriorate. Further, the filling material is in the form of particles or sheets, and the composition thereof is selected from at least one of metal, oxide, nitride, boride, silicide and carbon, or a combination thereof. Preferably, an oxide is used.

Further, when the filling material is granular, the particle size is preferably 0.3 mm or less.

If it exceeds 0.3 mm, the space between the filled granular materials becomes large, and the intended heat transfer coefficient cannot be obtained.

It is preferable that the value of n of the vapor flow diffusion control means has an upper limit of 3.

Here, the term "evaporation source" means a material formed of a magnetic material. In the present invention, for convenience of explanation, the term "evaporation source" includes an evaporation container containing the magnetic material as the evaporation source. It is assumed that there is.

[0026]

In the apparatus for manufacturing a magnetic recording medium according to the present invention, at least the n-th layer from the innermost layer and n +
Since the gap provided between the first layer and the first layer is filled with a filler having heat resistance and thermal conductivity, the heat of the inner layer in the two adjacent layers is transferred to the outer layer via the filler. Is done. Therefore, even if the dimensions of each layer are different due to the processing accuracy and a gap is generated between the layers, the filler filled in the gap transfers the heat of the inner layer to the outer layer, thereby transferring the heat between the layers. It can be performed well, and the temperature of the inner layer can be satisfactorily released to the outer layer. as a result,
It is possible to prevent the temperature of the inner wall portion from becoming too high and promoting the re-evaporation of the magnetic material attached to the inner wall portion too much, thereby lowering the vapor deposition efficiency.

[0027]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a magnetic recording medium manufacturing apparatus according to an embodiment of the present invention.
FIG. 1 shows a schematic configuration of an embodiment of a vacuum evaporation apparatus which is a magnetic recording medium manufacturing apparatus of the present invention.

The illustrated vacuum vapor deposition apparatus 1 has a cylindrical cooling can 4 inside a vacuum chamber 2, and a cylindrical film (outer peripheral surface) of the cooling can 4 has a base film 3 as a substrate of a magnetic recording medium. Is wound. The base film 3 is made of a polyester such as polyethylene terephthalate (PET) or polyethylene naphthalate, a polyolefin such as polypropylene, a cellulose dielectric such as cellulose triacetate or cellulose diacetate, a vinyl resin such as polyvinyl chloride,
It is formed by processing a plastic such as polycarbonate, polyamide, or polyphenylene sulfide into a long film, and the thickness thereof is, for example, 3 to 100 μm.

An undercoat is applied to the surface of the base film 3 if necessary. The undercoat is made of a binder (cellulose such as methylcellulose, P
Saturated polyesters such as ET, phenoxy resins, polyamides, polyacrylates, etc.) and fillers (silica, titania, alumina, calcium carbonate, etc.) are dissolved and applied. so,
It has protrusions with a density of 5 million to 100 million / mm ² . The height and density are appropriately selected depending on the required adhesion performance and the like.

Further, the base film 3 may be subjected to a pretreatment such as a glow discharge treatment, an ion irradiation treatment, a heat treatment, and a chemical treatment.

The base film 3 is wrapped around the winding shaft 6 from the delivery shaft 5 through the cylindrical surface of the cooling can 4, and rotates on the cylindrical surface of the cooling can 4 by rotating the cooling can 4 in the direction of arrow Y. For example, it is conveyed at a speed of 10 to 200 m / min, and is taken up by the take-up shaft 6. The cooling can 4 has a diameter
It is a cylindrical drum of 800 mm and width of 400 mm, the surface of which is hard chrome plated and mirror-polished to 0.2 S or less, and has a structure in which cooling water and other refrigerants (for example, ethylene glycol) are circulated inside. Is maintained at, for example, −35 to + 25 ° C.

On the surface of the cooling can 4, masks 13 and 14 whose main body is formed of SUS304 or the like are provided, and the cooling water or the coolant is circulated inside the cooling can 4 at a predetermined distance. This distance is between 2 and 15 mm, more preferably between 2 and 10 mm, most preferably between 3 and 5 mm. 2mm
If it is narrower, the space for installing the first gas blowing section described later cannot be secured, and if it is more than 15 mm, the vapor flow goes between the mask and the base film and adheres to the cooling can 4, causing contamination. Because. This is because the heat transfer coefficient between the can and the base film changes in the portion where the dirt is generated, or the base film is insufficiently adhered to the can, so that the can is easily damaged by heat. And base film 3
The maximum incident angle (θmax) is defined by the mask 13 located on the upstream side in the transport direction, and the minimum incident angle (θmin) is defined by the mask 14 located on the downstream side. The angle of incidence is based on the center of the circle of the melted surface in the refractory crucible 11a described later,
The maximum incident angle (θmax) defined by the angle between the line segment from the center of the circle to the edge of the mask 13 and the edge of the mask 14 and the normal line at the position of each mask edge on the cooling can 4 and regulated by the mask 13 Has an upper limit of 90 °, more preferably 87 °, most preferably an upper limit of 85 °, and the mask 14
It is desirable that the minimum incident angle (θmin) regulated by the above is set to a lower limit of 20 °, more preferably 25 °, and most preferably 30 °. This is because a desired holding power cannot be obtained if the above range is not satisfied. mask
The opening width of the mask opening 18 formed by 13 and 14 in the width direction (direction perpendicular to the transport direction of the base film 3) can be set arbitrarily.

The masks 13 and 14 have a curved shape along the front surfaces of the masks 13 and 14, respectively.
And has a function of preventing the evaporated metal particles of the magnetic material 10 from adhering to the surface of the base material 3, circulating cooling water inside, and a movable type having a main body formed of SUS304 or the like. (Not shown).

The vacuum chamber 2 is provided with a winding chamber 8 for feeding and winding the base film 3 by a partition plate 7,
The base film 3 is partitioned into a deposition chamber 9 for depositing a magnetic material. Each of the winding chamber 8 and the vapor deposition chamber 9 is provided with an exhaust system (not shown) for vacuuming, and the degree of vacuum in each chamber can be individually adjusted. In particular, since the oxidizing gas described below is introduced into the vapor deposition chamber 9 from outside the vacuum chamber 2, the degree of vacuum in the chamber and the partial pressures of various residual gases are constantly adjusted.

The take-up chamber 8 contains the base film 3.
For the pre- and post-treatments described above, for example, glow discharge treatment device, ion irradiation treatment device, heat treatment device, C
A VD processing device or the like may be provided. In addition, cooling can 4
Is not limited to a cylindrical shape, and may be an endless belt-shaped metal plate capable of forming a predetermined slope with respect to the evaporation source 11.

An evaporation source 11 provided with a magnetic material 10 is disposed below the cooling can 4 in the vapor deposition chamber 9. Around the evaporation source 11, an inside for heating the magnetic material 10 is provided. A high frequency induction heating coil 12 having a structure in which cooling water circulates is provided. Further, a high frequency power supply 13 for supplying high frequency power to the high frequency induction heating coil 12 and a high frequency power supply feeder 21 for transmitting high frequency power are provided.

The magnetic material 10 is made of, for example, Fe, Co, Ni,
CoNi, FeCo, FeCu, FeCr, CoCr,
CoCu, CoAu, CoPt, CoW, NiCr, C
oV, MnBi, MnAl, CoFeCr, CoNiC
r, CoRh, CoNiPt, CoNiFe, CoNi
It is appropriately selected from ferromagnetic metals and ferromagnetic alloys such as FeB, FeCoNiCr, and CiNiZn.

The refractory crucible 11a containing the magnetic material 10, which is a component of the evaporation source 11, is made of, for example, MgO, Zr
O ₂ , Al ₂ O ₃ , CaO, Y ₂ O ₃ , ThO ₂ , B
N, BeOCaO stabilized ZrO ₂ , Y ₂ O ₃ stabilized Zr
It is appropriately selected from ceramics such as O ₂ , carbon or a carbon compound, and other heat-resistant materials. The shape of the refractory crucible 11a is a container shape having a bottom, and the horizontal cross-sectional shape may be a true circle, an ellipse, an oval, a square, a rectangle, or any other shape, and the vertical cross-section may be a square. , Rectangular, trapezoidal, or any other shape. The high-frequency induction heating coil 12 is a refractory crucible 11.
Preferably, the shape corresponds to the side surface of a.

Further, the peripheral wall of the vapor deposition chamber 9 surrounds a path between the cooling can 4 and the evaporation source 11 having the magnetic material 10 and through which a vapor flow generated by evaporation of the magnetic material 10 passes. The vapor diffusion control means 15 is provided as described above, and an acidifying gas or an oxidizing gas and an inert gas (for example, N ₂ Ar gas) are provided near the cooling can 4 and near the masks 13 and 14.
And a first gas blowing unit 17 for blowing a mixed gas with the base film 3 toward the base film 3.

The gas spraying section 17 is located downstream with respect to the transport direction of the base film 3 and is built in the surface of the mask 14 on the side of the cooling can 4 near the mask 14 that regulates the minimum incident angle (θmin). ing. The blowing direction of the gas blowing slit 17a is a cooling can 4 that defines the minimum incident angle (θmin).
The direction is substantially parallel to the tangent line on the cooling can 4 at the upper reference point. The oxidizing gas is blown from the gas blowing unit 17 so that the oxidizing gas is blown in a substantially oblique direction with respect to the scattering direction of the evaporated particles that have passed through the opening of the vapor diffusion control means 15 described later, and a part of the evaporated metal particles. To oxidize.

The inner peripheral wall of the vapor diffusion control means 15 is made of, for example, MgO, ZrO ₂ , Al ₂ O ₃ , CaO, Y ₂ O ₃ , T
hO ₂ , BN, BeOCaO stabilized ZrO ₂ , Y ₂ O ₃
Evaporation steam flow path formed of ceramics such as stabilized ZrO ₂ , carbon or carbon compound, or other heat-resistant material and surrounded by a regulating surface extending substantially vertically in a state substantially continuous with the refractory crucible 11a The lower surface and the upper surface are opened to allow the passage of the evaporated particles of the magnetic material 10 and to improve the directivity thereof,
It is a cylindrical shape having only a peripheral wall, and the horizontal cross-sectional shape may be circular, elliptical, oval, square, rectangular, or any other shape. The vertical cross-section may also be square, rectangular, trapezoidal, or any other shape.

Further, the vapor diffusion control means 15 has a laminated structure composed of a plurality of members such as three layers of an inner wall portion 15a, an intermediate portion 15b, and an outer peripheral portion 15c on a concentric circle from the center of the opening to the outside. ing.

A heating structure including a heating source such as a resistance heater, a high-frequency induction heating coil, or the like, or cooling water, liquid nitrogen, liquid helium, ethylene glycol, Circulates refrigerant such as Fe, Cu, Al, Ni, Ti, Mg,
A configuration including a cooling structure formed of Zn, an alloy thereof, stainless steel, or the like can be employed.

The vapor diffusion control means 15 includes a refractory crucible 11a.
Evaporated particles of the magnetic material 10 that evaporate from the center point in the melt surface and fly upward from the point set as the reference point are used as a mask 13 for controlling the maximum incident angle and a mask for controlling the minimum incident angle, which will be described later. It is configured so as not to prevent adhesion in a continuous range from the maximum incident angle θmax to the minimum incident angle θmin defined by 14.

The refractory crucible 11a, the high-frequency induction heating coil 12, the high-frequency power supply 20, the high-frequency feeder 21 and the like are merely examples of the evaporation source, and the base film 3 extends in the width direction (perpendicular to the transport direction in the plane of the base film 3). When the width of the evaporation source 11 is large, the shape of the evaporation source 11 is changed according to the width of the base film 3 (for example, when the horizontal cross-sectional shape of the evaporation source 11 is elliptical and the width of the base film 3 is wide). The long axis direction of the elliptical shape of the evaporation source 11 is adjusted to the width direction of the base film 3), and a plurality of sets of the evaporation sources 11 arranged in the width direction of the base film 3 may be adopted. In this case, the evaporation source 11 (including the refractory crucible 11a), the high-frequency induction heating coil 12, the high-frequency power supply 20, the high-frequency feeder 21
Or a plurality of sets of the evaporation sources 11 are arranged independently, and a high-frequency induction heating coil 12, a high-frequency power supply 20,
It is also possible to adopt a configuration in which the high-frequency feeder 21 is shared.

[0046]

EXAMPLE The refractory crucible 11a of this example is cup-shaped (inner diameter φ80mm, outer diameter φ96mm, height 100mm, inner depth 90mm) and made of CaO stabilized ZrO ₂ (ZrO ₂ ; 90.0% ~
98.0%, CaO; 2.0% to 7.0%, MgO, Al
Each component of ₂ O ₃ , SiO ₂ , FeO ₃ and TiO ₂ is 0.0
% To 2.0%). Co ₁₀₀ was used as the ferromagnetic material 10 for evaporation inside the refractory crucible 11a.

The high-frequency induction heating coil 12 is composed of a Cu pipe having a diameter of φ12 mm through which cooling water circulates. The high-frequency induction heating coil 12 has six turns, an inner diameter of φ120 mm, and a height h12.
0 mm. Two high-frequency power supplies 20 having an oscillation frequency of 40 kHz and an output of 60 kW are installed outside the vacuum chamber 2, and two high-frequency power sources arranged inside the vacuum chamber 2 through a high-frequency feeder 21 and a vacuum feedthrough (not shown). Heating coil 12
Connected to. The high-frequency feeder 21 is made of a Cu plate, and the extended Cu pipe portions of the high-frequency induction heating coil 12 are each surrounded by an insulating tube made of Al ₂ O ₃ and are electrically insulated from each other.

The inner wall 15a of the vapor diffusion control means 15 has a cylindrical shape (inner diameter φ80 mm, outer diameter φ102.0 mm, height h75 mm),
The material is CaO stabilized ZrO ₂ (ZrO ₂ ; 90.0% ~
98.0%, CaO; 2.0% to 7.0%, MgO, Al
Each component of ₂ O ₃ , SiO ₂ , FeO ₃ and TiO ₂ is 0.0
% To 2.0%). The middle part 15b is cylindrical (inner diameter φ102.
6 mm, outer diameter φ114 mm, height h75 mm).
Graphitic carbon and BN were used. Further, a slight gap is provided between the inner wall portion 15a and the intermediate portion 15b.

The outer peripheral portion 15c has a cylindrical shape (inner diameter φ114 mm, outer diameter φ150 mm, height h75 mm), circulates cooling water at 18 ° C. inside, and forms a cooling structure having a main body made of Cu. Using.

The gap between the inner wall portion 15a and the intermediate portion 15b is filled with a filler 30 made of CaO-stabilized ZrO ₂ powder (particle diameter: 0.3 mm or less) formed by adding a small amount of water to form a cement. Thereafter, baking was performed at a temperature of 250 ° C. for 2 hours.

On the other hand, the intermediate portion 15b and the outer peripheral portion 15c were assembled by press fitting.

Next, the operation of the magnetic recording medium manufacturing apparatus of this embodiment will be described.

First, a gas such as air in the vapor deposition chamber 9 and the winding chamber 8 is exhausted to the outside by a pressure reducing means (not shown) such as a vacuum pump. For example, 5.0 × 10 ^{-5 to} 4.0 × 10 ^-4 To
The pressure is reduced to rr. After the insides of the vapor deposition chamber 9 and the winding chamber 8 are depressurized as described above, electric power is supplied to the high-frequency induction heating coil 12 using the high-frequency power supply 13, whereby the high-frequency induction heating coil 12 generates heat and 11 magnetic materials
10 was heated and evaporated.

[0054] For the heating method of the magnetic material 10, the base as the conveying speed of the film 3 is 80 m / min, in terms to 1800 / min O ₂ gas at atmospheric pressure conditions as the oxidizing gas from the first gas blowing section Sprayed with width, mask opening width is 285 mm
A preliminary test was performed to determine the required input power in a steady state sufficient to secure an evaporation rate of 1600 Å under the above conditions, and the holding time until the evaporation rate was obtained. Here, the holding time is defined as the time from the start of supplying a certain amount of power, the temperature of the magnetic material 10 rising, melting, and until the entire evaporation source is sufficiently heated to reach a thermal equilibrium state until a constant evaporation rate can be maintained. Time.
From the results of this preliminary test, the power value to be initially supplied and the holding time were determined to be 20 KW and 30 minutes, respectively.

After the elapse of the holding time, the base film 3 was transported from the feed shaft 5 at a transport speed of 80 m / min and a tension of 8.0 kgf / min.
The base film 3 was sent out under a condition of 300 mm, subjected to a glow discharge treatment using O ₂ gas on the side of the base film 3 on which the magnetic thin film was formed, and then transported on the cooling can 4. . Then, the shutter device is driven to the "open" state, and at the same time, the spray amount 1800
After a Co-O magnetic thin film of 1600 Å is formed on the base film 3 while blowing O ₂ gas at a flow rate of cc / cc, the winding length is continuously wound on the winding shaft 6.
After the formation of the metal magnetic thin film of 00 m, the shutter device is set to the “closed” state, and at the same time, the O
The spraying of the _two gases and the supply of power from the high-frequency power supply 20 were stopped to terminate the film formation.

Thereafter, in a separate step, a mixture of a phosphoric acid lubricant + a perfluoropolyether lubricant and a rust inhibitor (benzotriazole) was dissolved and applied to the surface of the magnetic thin film.
Dissolve and disperse a mixed material of non-magnetic powder mainly composed of carbon black, nitrocellulose, polyester, polyurethane and isocyanate hardener on the back surface,
It was applied with a thickness of μm.

The total weight W _ms (g) of the ferromagnetic material 10 before melting.
From the difference between the W _me of deposition after the end of the residual material (g) and of calculating the evaporation total amount W _mev (g) from the difference, the base after the deposition based the total weight of the pre-deposition total weight W _{be (g)} Deposition total weight W
_{Calculate bev} (g). And the total amount of evaporation W _mev (g)
The ratio of the total deposition weight W _bev (g) to the vapor deposition efficiency
(%), The following relationship is obtained.

Ξ (%) = W _bev (g) / W _mev (g) × 100 (%) As a comparative example, the inner wall portion 15 a and the intermediate portion 15 in the above embodiment are used.
b, a vapor diffusion control means 15 in which ZrO ₂ powder is not filled in the gap between the inner wall 15a and the vapor deposition efficiency ξ (%) is prepared.
The state of cracking was compared. The results of the comparison are shown in Table 1 below.

[0059]

[Table 1]

By filling the filling material 30, a remarkable heat insulating layer was eliminated, and the vapor deposition efficiency was improved by about 3.0%. Further, no adverse effect (for example, cracking of the inner wall portion) was caused by filling the gap between the inner wall portion 15a and the intermediate portion 15b with the filler 30. This is presumably because the filler 30 is in a powder form and absorbs a certain degree of shape deviation due to thermal expansion or other distortion.

As the filler 30, metal powder, sheet, etc. can be used in addition to ZrO ₂ powder as in the above-described embodiment. Table 2 below shows the case where the filler 30 is variously changed. Shows the vapor deposition efficiency of.

[0062]

[Table 2]

In each case, good vapor deposition efficiency could be obtained as in the above-described embodiment.

In this embodiment, the experimental results are shown for the vapor diffusion control means having a three-layer structure in which n = 2, but a two-layer structure in which n = 1 and n = 3. Similar experimental results were obtained for the four-layer structure.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of a magnetic recording medium manufacturing apparatus according to the present invention.

FIG. 2 is a diagram showing details of a vapor diffusion control means.

FIG. 3 is a diagram showing a conventional apparatus for manufacturing a magnetic recording medium.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum vapor deposition apparatus 2 Vacuum tank 3 Base film 4 Cooling can 5 Delivery axis 6 Winding axis 7 Partition plate 8 Winding chamber 9 Deposition chamber 10 Magnetic material 11 Evaporation source 11a Refractory crucible 12 High frequency induction heating coil 13,14 Mask 15 Vapor diffusion control means 17 First gas spraying part 18 Mask opening

Claims (1)

[Claims] 1. A transport means for transporting a long flexible substrate in a vacuum atmosphere, an evaporation source made of a magnetic material disposed below which the substrate is transported, and heating and evaporating the evaporation source. An evaporating means, a vapor flow diffusion control means disposed between the evaporating means and the flexible substrate, for regulating and controlling a diffusion direction of a vapor flow heated and evaporated by the evaporating means, and An apparatus for manufacturing a magnetic recording medium for forming a magnetic thin film on the flexible substrate, comprising: an incident angle restricting means for restricting an incident angle to the flexible substrate; A plurality of cylindrical layers stacked from the inside to the outside, and a gap is provided between at least the n-th layer from the innermost and the (n + 1) -th layer (n: a natural number) among the respective layers; In the gap, the thermal conductivity is 0.03kcal / mh ℃ ～ 500kcal / mh ℃ Apparatus for manufacturing a magnetic recording medium, characterized in that the material filled with.