JPS62271221A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve recording and reproducing characteristics, corrosion resistance and durability by laminating a magnetic material layer on a substrate, then forming an org. protective layer contg. a polymerized monomolecular film of a polymerizable compd. or the cumulative film thereof on said layer and further subjecting the resulted laminated to a heat treatment and/or vacuum treatment. CONSTITUTION:The ferromagnetic material layer 2 is laminated on the substrate 1 and an intermediate layer 3 to play the role of a subsurface treatment is provided thereon, then the org. protective layer 4 contg. the polymerized monomolecular film of the polymerizable compd. or the cumulative film thereof is formed thereon. The resulted laminate is subjected to the heat treatment and/or vacuum treatment. The adhesiveness of the intermediate layer 3 and the protective layer 4 is improved and the protective layer 4 itself is stabilized by subjecting the thin magnetic film formed with such protective layer to the treatment and/or vacuum treatment. A thin film deposition type magnetic recording medium having the particularly excellent durability and runnability is thus obtd. without the substantial deterioration of the electromagnetic conversion characteristic.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method of manufacturing a thin film deposition type magnetic recording medium for high-density recording that has excellent durability and environmental resistance.

[Prior art] Conventionally, coated IF'i type magnetic recording media have a magnetic layer in which fine ferromagnetic particles are uniformly dispersed in a polymer binder on a non-magnetic substrate F made of a plastic film such as polyester. is widely used.

In addition, in recent years, the development of ferromagnetic thin films (W magnetic recording media), in which a thin film of metal is formed as a magnetic layer on a non-magnetic substrate F by methods such as sputtering, has been progressing, and some have been put into practical use. be.

The magnetic properties, corrosion resistance, abrasion resistance, and friction coefficient 1 shape (curl, deformation) of the magnetic layer are factors that affect the performance of a magnetic recording medium, and these performance factors are dependent on the material and manufacturing method of the magnetic layer, It depends on the substrate, the protective fi+71 lubrication or layer). The magnetic layer material has a large magnetic flux density,
Ferromagnetic thin film magnetic recorder that can be made thinner! ! Media or traditional coating I
It is superior to JI type magnetic recording media.

However, the Go--Ni alloy film, which is typical of the strong flaky thin 11Q+%'4 71-tape, which forms the magnetic layer, does not have sufficient corrosion resistance and durability for practical use. That is, Co
The Ni alloy itself is not a corrosion-resistant alloy, and because it is formed by oblique vapor deposition for the purpose of improving properties, it has a low density and is easily oxidized. Therefore, there is a method of oxidizing the surface of the Co-Ni alloy film (JP-A No. 53-8540:), and a method of forming a protective layer of oxide or nitride on the north side of the Co-Ni alloy film (JP-A-Sho 53-8540). 57-167134 etc.), Ga
-Method of applying rust preventive to Ni alloy film (Japanese Patent Laid-Open No. 57
Corrosion resistance methods such as No. 1525.18 have been studied, but there was a problem in that sufficient corrosion resistance was not guaranteed because the thickness of the Go-Ni alloy film itself was thin and the density was low. Furthermore, a method is known in which a protective layer consisting of a molecular film of a polymerizable compound is formed on a Go-Ni alloy film by the Langmuir-Prodgett method (Japanese Patent Application Laid-Open No. 61-48124). The winner is weather resistance, durability, and running performance. However, if the protective layer is thinned to maintain high electromagnetic conversion characteristics, its durability and runnability will be less than 1 minute, and if the protective layer is made thicker, high-density i There was a problem that recording was not possible.

(Object of the Invention) The present invention has been made in view of the problems of the conventional technology t4i, and its purpose is to provide a magnetic material that has excellent recording and reproducing characteristics and has practically sufficient performance in terms of corrosion resistance and durability. The goal is to provide recording media.

[Steps to solve the problem]

The purpose of the E layer of the present invention is to laminate a magnetic material layer on a substrate, and then form an organic protective layer containing an m-combination qt molecule-film of a polymerizable compound or a cumulative film thereof on the magnetic material layer. This is achieved by a method for manufacturing a magnetic recording medium in which a laminate is subjected to heat treatment and/or vacuum treatment.

FIG. 1 is a schematic diagram showing a preferred structure of a magnetic recording medium manufactured by the method of the present invention, in which 1 is J, 1 body, 2 is a ferromagnetic layer, 3 is an intermediate layer that serves as a base treatment, and 4 is an organic protective layer.

Materials for forming the base 1 include glass, aluminum, surface oxidized aluminum, etc., as well as polymer support materials such as polyester, cellulose, acrylic, polyamide,
Polyimide, polyamideimide, polyolefin, polyfluoroolefin, polyvinyl chloride, polyvinyl acetate, vinyl chloride/vinyl acetate copolymer, polyvinylidene chloride, polycarbonate, phenolic resin, bosoether sulfone, polyether needle ketone, polyacetal, polyphenylene oxide , polyphenylene sulfide, and the like.

The materials forming the ferromagnetic layer 2 include Fc, Go, and Ni.
It is possible to use alloys mainly composed of Go-Cr alloys, or their oxides, nitrides, etc., or Go-Cr alloys, which have excellent high-density recording characteristics and excellent corrosion resistance, or ferromagnetic alloys whose main components are Go-R gold alloys. Membranes are preferred.

In order to obtain a magnetic recording medium with excellent electromagnetic conversion characteristics, it is desirable that the ferromagnetic layer 2 has a large coercive force. When the ferromagnetic layer 2 is a Go-Cr alloy film, it is preferable to set the formation temperature of the Go-Cr alloy film at a high temperature (1130°C-3[)0°C) due to its coercive force direction. In this case, it is preferable to use heat-resistant polyamide or polyimide resin, especially aromatic polyimide resin, among the above-mentioned materials, as the substrate 1.

Furthermore, it is important from the viewpoint of runnability and head touch that the magnetic recording media obtained by the present invention, such as floppy disks and magnetic tapes, do not curl. In order to create a curl-free magnetic recording medium, it is necessary to select a material for the substrate 1 that has a thermal expansion value that cancels out the thermal stress with the Go-Cr alloy film and the stress that occurs during film formation. .

The case where an aromatic polyimide film is used as the substrate 1 will be described below.

As the aromatic polyimide membrane (film), paraphenylenecyamine (PPD) is used alone as the cyamine component, or PPD and diaminodiphenyl ether (DE to D) are used together, and as the tetracarphonic acid component, Biphenyltetracarboxylic dianhydride (BPD)
8) and pyromellitic dianhydride (to PMD), a solution of aromatic polyamic acid obtained by copolymerization was prepared, and then imidized to produce an aromatic polyimide L15! (film) is preferred, and those having a thickness of 4 μL to 100 μL are useful as recording media.

This aromatic polyimide film is made of PPD as described above.
, BPDA and PMDA or PPD, D
ADE.

Since it is formed by copolymerizing the four components of BPDA and PMDA, it not only has excellent heat resistance and tensile elasticity, but also can be obtained by adjusting the usage ratio of each component that makes up the image component. The coefficient of thermal expansion of the aromatic polyimide film can be set to a value that roughly matches the coefficient of thermal expansion of the strong ftfi material, and the tensile elastic constant of the aromatic polyimide film can be adjusted depending on the application, such as stiffness, etc. can be modified to suit the performance of the

This aromatic polyimide film has a thermal expansion coefficient of about 1.0X]0-S to 3. OX 10-' cm/c of 7
℃ range, and the tensile elastic constant is approximately 300 to 1200k
g/mm2. In particular, the range is from 325 to 700 kg/+nm2, and the second-order transition temperature is about 300°C or higher, especially 3
It is preferable that the temperature is 10°C or higher, and in addition to the above-mentioned performance, the temperature at which thermal decomposition starts is about 400°C or higher, particularly 450°C or higher.
℃ or higher and can withstand continuous use at temperatures around about 250℃, and has a tensile strength in a tensile test of about 20 kg/mm' or higher, especially about 25 kg/+nm.
2. Those with an elongation rate of about 30% or more, especially 40% or more at the break point, exhibit excellent heat resistance when manufacturing magnetic recording media, and can form magnetic layers at high temperatures. In addition, it is optimal because it can prevent the occurrence of curling, and also provides a magnetic recording medium with excellent winding unevenness, runnability, and head touch.

The aromatic polyamic acid used to obtain the aromatic polyimide is used as a diamine component for the production of the magnetic recording medium in order to make the mechanical and thermal properties of the magnetic recording medium suitable as described above. about 40 to 95 mol%,
In particular, PPD with a usage proportion in the range of 45 to 90 mol % and about 5 to 60 mol %, especially 10 to 5 mol %, based on the total diamine component.
Preferably, it consists of two components with DADE in an amount of 5 mol %. Further, the tetracarboxylic acid component for producing the aromatic polyamic acid is about 10 to 90 mol%, particularly 15 to 85 mol%, based on the total tetracarphonic acid component.
It is preferable to use BPDA in an amount of about 10 to 90 mol %, particularly 15 to 85 mol % of PMDA, based on the total tetracarboxylic acid component.

Furthermore, in order to control the unevenness of the film surface, polyimide films made of such components may be filled with carbon black, graphite, fine silica powder, fine magnesia powder, titanium oxide, calcium carbonate, and other fillers as necessary. It is also possible to knead. However, in order to provide excellent high-density recording characteristics to the magnetic recording medium manufactured according to the present invention, it is desirable that the maximum height of the surface roughness of the substrate (Rmax) is 0.05 μj or less. .

Go-(
: To form a magnetic layer made of r alloy, known methods such as sputtering and continuous electron beam evaporation can be used, but these JT methods can be used to form a magnetic layer on the surface of the aromatic polyimide film described in 11tc. When doing so, the film temperature (film forming temperature) can be raised to about 250° C., so a magnetic layer with excellent performance can be easily formed.

The advantage of the Go-Cr alloy as a magnetic recording layer is that it has magnetic anisotropy perpendicular to the film surface, resulting in a perpendicularly magnetized film, and is not affected by demagnetizing fields during short wavelength recording.

That is, since it is not necessary to make the magnetic layer extremely thin, it is possible to have a sufficient thickness to achieve high output.

The thickness of the magnetic layer 2 made of this Go-Cr alloy is 0.1μ.
Preferably, the amount is in the range of m to 2.0 ul, and in addition to directly forming the magnetic layer on the substrate 1, prior to forming the magnetic layer, it may be subjected to other treatments such as improving adhesion, improving magnetic properties, and corona discharge treatment and other treatments as necessary. AM, Ti
, Cr, Ge, 5i02. Non-hexavalent film such as 2,03, or Fe-Ni alloy film, or Co-7,r
.

It may be provided through a high magnetic permeability film typified by an amorphous film such as Fc-P-C or Fc-tl:o-5i-B.

These Go<r alloy/base magnetic thin films can be formed on both sides of the substrate 1 if necessary.

An intermediate layer is provided on the surface of the ferromagnetic layer 2 as described above in order to improve the adhesion with the organic protective layer 4 described later.

As the intermediate layer 3, a layer made of cobalt oxide is particularly preferable from the viewpoint of sliding properties. The cobalt oxide layer is formed by a sputtering method in an inert gas containing oxygen at a predetermined pressure, a vacuum evaporation method under diluted oxygen, a physical vapor deposition method such as an ion blasting method, or a plasma oxidation treatment.
The thickness of the intermediate layer 3 is the same as that of the Go-(:r alloy magnetic layer). In order to effectively utilize the high-density recording characteristics, it is desirable that the intermediate layer 3 be thin in order to reduce spacing loss, and the thickness of the intermediate layer 3 should be 30 to 30 mm.
300 people are preferred, and 50 to 150 people are particularly preferred.

However, it is appropriate to keep the combined thickness of the intermediate layer 3 and the organic protective layer 4 to preferably 250 Å or less, more preferably 120 Å or less.

The organic protective layer 4 is a layer consisting of a polymerized monomolecular film of a polymerizable elementary compound (hereinafter referred to as an amphipathic polymerizable compound) having both a hydrophilic site and a hydrophobic site in its molecule, or a cumulative film thereof. For formation, such a monomolecular film or a cumulative film thereof is subjected to heat treatment at 50 to 100°C or vacuum treatment at room temperature to 70°C.

Examples of the amphiphilic polymerizable compound constituting the organic protective layer 4 include compounds having the structure shown below.

■ (:11.=(:H(CH2)k-R■ II((
:Hz)m (jC-C=(knee(1:Hz)n
R■ CH3(CH2)k(:00(:H=el+2
In the above compounds, R is a hydrophilic moiety, specifically, -COOH, -CH20H, -5O3H, -COOC)
I3. -C: H2S1l-OX (X-C), [lr
, I, BF4. PF6. TCNQ.

TCNQ2 etc.).

In addition, regarding the compound of ■■■, k is an integer of 8 to 28,
Preferably it is 16-20. Regarding the compound (2), m and n are each an integer of 0 to 2B, and the sum of m and n is an integer of 12 to 35.

As a method for creating a monomolecular film or a monomolecular cumulative film of the above amphiphilic polymerizable compound, for example, 1. The Langmuir-Prodgett method (hereinafter referred to as LB method) developed by Langmuir et al. can be used.

That is, first, the target amphipathic polymerizable compound is dissolved in a solvent such as chloroform. Next, Figure 2(a)
, Using the apparatus shown in (b), a solution of the amphipathic polymerizable compound is spread on the aqueous phase 14 to form the amphipathic polymerizable compound into a film shape.

At this time, when using an amphiphilic polymerizable compound having a carboxyl group at the end, a desired metal ion, such as Ag", (:u", Li") is added in advance to the aqueous phase I4.

Na”, K”, B a44, Ca++, Go+4, C,
++, Cd”, Mg +4, MO+4, pb”, Cu”
, Fe++, Ni++, Zn++, co+4 +, C
, ++ 4. Fe44 +, At””, RuAno,
1. By dissolving a++4, etc. and ammonium ions, these salts can be formed into a membrane.

At that time, the ratio of substitution of the hydrogen atom f of the carboxyl group with these metal ions or ammonium ions is determined based on the aqueous phase 1.
The pH of 4 and the concentration of the above ions are satisfactory, and by adjusting the ion concentration, any ratio can be obtained.

Next, in order to prevent this spread layer from spreading freely on the water phase and spreading too much, a partition plate (or float) 7 is provided to limit the spread area and control the aggregation state of the membrane material. Obtain surface pressure. By moving the partition plate 7 and reducing the developed area, it is possible to control the aggregation state of the membrane material, gradually increase the surface pressure, and set the surface pressure suitable for producing a cumulative membrane. By gently moving the clean carrier 15 up and down vertically while maintaining this surface pressure, the molecular film of the amphiphilic polymerizable compound is transferred onto the carrier 15. Here, the term "carrier" refers to the magnetic thin film described above. In this manner, a monomolecular film of the amphiphilic polymerizable compound can be formed on the intermediate layer 3.

A monomolecular film of the amphipathic polymerizable compound is produced in this manner, and by repeating the above-mentioned operations, a desired cumulative number of monomolecular films of the amphipathic polymerizable compound can be formed.

In order to transfer the monomolecular film of the amphiphilic polymerizable compound onto the carrier, in addition to the above-mentioned vertical dipping method, methods such as the horizontal adhesion method and the rotating cylinder method can also be employed.

The horizontal adhesion method is a method in which the carrier is brought into horizontal contact with the water surface and transferred, and the rotating cylinder method is a method in which a cylindrical carrier is rotated on the water surface and transferred onto the carrier surface.

In the vertical immersion method described above, when a carrier with a hydrophilic surface is lifted out of water in a direction across the water surface, a monomolecular film is formed on the carrier with the parent group of the amphiphilic polymerizable compound facing the carrier. . When the carrier is moved up and down as described above, one monomolecular film of the amphipathic polymerizable compound is stacked on top of the other with each step. Since the direction of the film forming component Y- is reversed between the pulling process and the dipping process, this method forms a Y-shaped film in which the parent group and the hydrophobic group of the amphipathic polymerizable compound face each other between each layer. . In contrast, in the horizontal adhesion method, a monomolecular film is formed on the carrier with the hydrophobic groups of the amphipathic polymerizable compound facing the carrier side. In this method, there is no change in the orientation of the film-forming molecules even if they are accumulated, and an X film is formed in which the hydrophobic groups face the carrier side in all layers. On the contrary, a cumulative film in which the hydrophilic groups in all layers face the carrier side is called a Z-type film.

The method of transferring the monomolecular layer onto the carrier is not limited to these methods, and when a large-area carrier is used, a method of extruding the carrier from a carrier roll into an aqueous phase may also be used.

Furthermore, the orientation of the aforementioned parent wood group and hydrophobic group toward the carrier is a general rule, and can be changed by surface treatment of the carrier.

By irradiating energy such as X-rays, ultraviolet light, heat, etc. to the monomolecular film or monomolecular cumulative film of the amphiphilic polymerizable compound formed on the carrier, that is, on the intermediate layer 3, when the above-mentioned method is difficult. For example, an amphipathic polymerizable compound can be prepared using the following reaction formula (1).
) to (3) to obtain a polymerized monomolecular film or a polymerized monomolecular cumulative film.

n-C112-Cl1 (CH2)k-R→(ni112
CHTh (1)(C:H2)k-Rn-tl ((:H2)m-c=c-c=c-(cH
2)n-R→ H(C:H2)Tn(2) ■ groan c-c=c-c +1 (C)Iz)n -R n -CH3(Ctl 2)k(:0(]CH= CH
2→ CH3(CH2)kcOO(3) fCll-CHz+n It is also possible to carry out the polymerization reaction in a monomolecular film developed on the water surface, and in that case, it is possible to directly deposit a polymerized monomolecular film on the carrier. Or a polymerized monomolecular cumulative film is formed.

The polymerized monomolecular film and polymerized monomolecular cumulative film of the amphiphilic polymerizable compound formed on the intermediate layer by the above-mentioned method are ultra-thin films with a high degree of order (thickness per monomolecular layer is 220 ~
35 people), and when a protective layer is formed with these %, it becomes possible to significantly reduce the influence on the electromagnetic conversion characteristics. At this time, the intermediate layer (particularly the cobalt oxide layer) 3 which is the base of the organic protective layer is made of G o -Cr
Cobalt oxide layer (especially cobalt oxide layer) 3 is Go
-Cr has higher hydrophilicity than the magnetic layer 2, and therefore stronger adhesion can be maintained compared to the case where an organic protective layer is formed on the Go-Cr &fi layer.

The thickness of this protective layer is preferably in the range of 15 to 100 layers.

By subjecting the magnetic thin film on which such a protective layer has been formed to heat treatment and/or vacuum treatment, the adhesion between the intermediate layer 3 and the protective layer 4 is improved, and the protective layer 4 itself is stabilized, essentially improving the electromagnetic conversion characteristics. Particularly durable, without reducing
In addition, a thin film deposition type magnetic recording medium with excellent running properties can be obtained.

As for the heat treatment, heating at an environmental temperature of 40° C. to 90° C. for 1 minute to 30 minutes is appropriate, although it depends on the materials of the substrate and the organic protective layer. In addition, as for vacuum treatment, 1O
It is appropriate to expose the sample to a reduced pressure of -2Lorr to 10-' Lorr for 5 minutes to 10 minutes.

Of course, both heat treatment and vacuum treatment may be performed.

In the Co-Cr alloy ferromagnetic thin film deposited magnetic recording medium obtained by the present invention, a magnetic recording layer is formed on at least one surface of the substrate of the magnetic recording medium, and a magnetic recording layer is formed on the opposite surface. If necessary, a thin film symmetrical to the surface may be laminated, or various back coat layers may be formed to provide protection, lubricity, reinforcement, and other effective effects to the substrate. Also good. The back coat layer includes AI, Ti, V, Zr, (:o, Nb,
Ta, W, (:r, thin films of metals such as Si, Ge, semimetals or their oxides, nitrides, carbides, or oxide fine particles, easily slippery fine particles such as calcium carbonate, and conductive particles such as carbon, metal powder, etc. Examples include those obtained by kneading and coating a polymer binder such as a thermoplastic or thermosetting resin containing rubber particles and at least one type of lubricant such as a fatty acid or a fatty acid ester.

〔Example〕

Hereinafter, the present invention will be explained in more detail by giving specific examples of the present invention.

[I] Manufacture of magnetic tape <Tape evaluation method> Output frequency characteristics: 0.75 Hz, 4.5 MHz, 7.5 MHz 1
il---record one signal and measure the playback output.

Still durability test: Measured changes in still playback output over time in environments of 20°C, 65% and 0°C. If the output decreases within 3 dB after 20 minutes, it is considered O.

Corrosion resistance test: If the saturation magnetic flux density decreases by 10% or less after being left at 50°C and 80% for 1000 hours, it is considered O.

Example 1 In a polymerization kettle with an internal volume of 300 ft, 20 moles of 3.3',4.4'-biphenyltetracarboxylic dianhydride, 80 moles of pyromellitic dianhydride, 70 moles of phenylene diamine, and 4 .4-Diamine diphenyl ether;
A base film of an aromatic polyimide membrane having a thickness of 10 μm was manufactured using 30 mol of the raw material.

Various physical properties of this aromatic polyimide film were measured, and as a result, the tensile elastic constant was 490 kg/mm.
2. Thermal expansion coefficient α is 1.6X at 100-300℃
l O'cm/am/"C1RZ (JIS B
The average score of 10 points according to 0601 was 80 people.

Using this aromatic polyimide film as a base film, Go 7 was applied to the surface of the base film using a continuous magnetic tape film forming apparatus equipped with an electron beam heating device
8wL'< -Cr 22wt1 perpendicularly magnetized vapor deposited film with base film temperature of 200°C, 0.1 μm/s
After forming a film with a thickness of about 0.4μ at a film formation rate of EC, CO is sputtered on top of it in argon gas containing 10% oxygen.
A cobalt oxide thin film was formed to a thickness of 80A.

Next, an amphiphilic diacetylene compound shown in formula (4),
10.12-Pentacosacitic acid, C1IA (Ct
b) ++ C=C-CEC-(CH2)B(:OOH
After dissolving (4) in benzene (concentration 117 ml), manganese chloride 4Xl (pH 7 containing 1 layer M, water temperature 20
It was spread on an aqueous phase 14 (FIG. 2) at ℃ and deposited in the form of a film.

After evaporating the solvent, the surface pressure was increased to 20 mN/m. While keeping this surface pressure constant, using the above-mentioned magnetic thin film as a carrier,
The carrier was pulled out of the water in a direction across the water surface at a speed of 10 mm/min, and a monomolecular film of 10.12-pentacosasiitoic acid manganese salt was formed on the carrier. The magnetic sheet thus obtained was irradiated with a 200W high-pressure mercury lamp to polymerize 10.12-pentacosasiitic acid manganese salt, and then heat-treated in a constant temperature oven at 80°C for 15 minutes, and then 8,0+n+r+ It was slit to the width.

The curl of this tape is small, -< O, lmm-'.
The amount of soil was not a problem for practical use. This tape is 8mm VT
Attached to an R tape cassette, output frequency characteristics, still durability, 50℃/8096 with an 8mm video deck.
[(Corrosion resistance test etc. at 1 ton were conducted.

The results were very good as shown in Table 1.

Example 2 A tape was prepared in the same manner as in Example 1, except that the 10.12-pentacosacyitic acid manganese salt nutrient 7' film in Example 1 was accumulated in three layers, and the performance was evaluated. The results are shown in Table 1. The results were as good as those of the m-molecule-membrane.

Example 3 Amphiphilic diacetylene compound represented by the following formula (5), 2.
1-tricosacitic acid C113 (C1h)+7- C=C-C=C-C00I
After dissolving I (5) in Hensen (concentration img/(Ill)), cobalt chloride (II
) 1 x 10-3M in pl+9.5 and water temperature 20°C on the aqueous phase 14 (Fig. 2) to form 2,4-tricosacitic acid cobalt salt in the form of a film.

The solvent was removed 7/2 times M2, and the surface pressure was increased to 20 mN/m. After purging the gas phase side with nitrogen and keeping the surface pressure constant, a high-pressure mercury lamp was irradiated onto a single molecule of cobalt 24-tricosacitic acid salt spread on the water surface, and this was combined. . Next, a Co-Cr luminescent thin film containing a 119-thick 80-layer cobalt oxide film was prepared in the same manner as in Example 1 while keeping the surface pressure constant at 20 mN/m.
The carrier was lifted out of the water in a direction across the water surface at a speed of 10 mm/min, and a polymerized monomolecule of 2,4-tricosacitic acid cobalt salt was formed into the carrier. The electrical sheet thus obtained was subjected to vacuum heat treatment for 5 minutes in a vacuum constant G furnace at 60° C. (vacuum degree 10-'torr), and then slit with a width of 8.0 m+n. The performance of this tape was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1.2 The performance of tapes obtained in Examples IBt and 3 was evaluated in the same manner as in Examples IBt and 3, except that the heat treatment and vacuum treatment steps were omitted. The results are shown in Table 1.

[+1 Evaluation method for manufacturing magnetic disks] Using a still video deck (prototype), the playback output, durability, and output fluctuations in the circumferential direction (output unevenness) were measured, and the durability was continuous 5.
If the output decreases by 6 dll or less after 0 hours of playback, it is rated O. Output unevenness indicates the difference between the maximum and minimum output values in one track.

Example 4 3.3′,4.4-biphenyltetracarboxylic dianhydride: 40 mol, pyromellitic dianhydride: 60 mol, paraphenylenediamine: 50 mol, and 4,4′-diaminodiphenyl ether, 50 mol A solution composition of aromatic polyamic acid was produced in the same manner as in Example 1 using the following monomer components and component ratios. Using the thus obtained nine-layer solution composition, a thickness of 40 μm was prepared in the same manner as in Example 1.
An aromatic polyimide film of s was manufactured.

This aromatic polyimide film has a tensile elastic constant of 400
kg/mm', too Thermal expansion coefficient α at ~300℃ 2.6x 10'c+n/cm/"C1Ry,
There were 30 people.

This polyimide film is used as a base film, and the base film F is
A perpendicularly magnetized film of Co 80wtJ - Cr 20w1J was applied to the base film at a temperature of 150°C, about 05μ
After the top layer is formed, CO is sputtered on a part of it in argon gas containing 12% oxygen to form a cobalt oxide thin film of 100%.
The people were thick.

Next, an amphiphilic olefin compound shown in the following formula (6),
ω-Trichosenic acid Cll2-Cll (Cll, ),. C00I+
(5) was dissolved in chloroform (concentration 11D/
After that, the mixture was spread on an aqueous phase 14 (Fig. 2) containing cadmium chloride 5xlO-' at pH 8.5 and water temperature of 20°C (Fig. 2) to precipitate ω-tricosenoic acid cadmium salt in the form of a film. After evaporating the solvent, the surface pressure was increased to 30 mN/m.

While keeping this surface pressure constant, the magnetic thin film is used as a carrier, and the carrier is lifted out of the water in a direction across the water surface at a speed of io+nm/mi, and the ω-tricosenoic acid cadmium salt monomolecular film is placed on the carrier. Created. Further, the carrier was gently moved onto a plate at a speed of 10 mm/min to produce a monolayer of three layers. After the magnetic sheet thus obtained was exposed to X-rays, it was heat-treated in a constant temperature oven at 80° C. for 15 minutes.

The sample thus obtained was punched into a disk with a diameter of 47 mm, and evaluated using a Viteo Disc IF gray machine.

The results were very good as shown in Table 2.

Example 5 A disk was prepared in exactly the same manner as in Example 6, except that the organic protective layer in Example 4 was changed to cadmium salt 1'11'7-1 of 10.12-pentacosacyitic acid.

Polymerization reaction is 2001! This was done by irradiating it with a mercury lamp.

At this time, the aqueous phase 14 was prepared to contain cadmium chloride 5 x 10-'M, pH 6.8, and water temperature 20°C as conditions for producing the medium molecule. Further, film formation was carried out under a surface pressure of 20+nN/m and at a drawing speed of 10 mm/min. Table 2 shows the results of performance evaluation of such disks.

Comparative Example 3.4 The performance of disks obtained in Examples 4 and 5 was evaluated in exactly the same manner as in Examples 4 and 5, except that the heat treatment step was omitted. The results are shown in Table 2.

Comparative Example 5 A metal-coated magnetic sheet with a diameter of 47 mm in which a pure iron-based magnetic material was coated instead of the cobalt oxide layer and the 10.12-pentacosacyiic acid manquatin salt layer in Example 1 was used.
A disc was punched out and evaluated using a video disc player. The results are shown in Table 2.

〔Effect of the invention〕

As explained above, according to the method for manufacturing a magnetic recording medium according to the present invention, it is possible to realize a high-density magnetic recording medium that is excellent in runnability, durability, and environmental resistance.

A detailed explanation of the cylinder Figure 1 is a diagram showing the configuration of a magnetic recording medium manufactured by the present invention, and Figures 2 (a) and 2 (b) are diagrams showing the structure of a magnetic recording medium manufactured by the present invention. This is an apparatus for forming a single film of li molecules.

■...Substrate, 2...Ferromagnetic layer, 3...
・Intermediate layer, 4...Organic protective layer, 5...Aquarium, 6...Frame, 7...Partition plate,
8... Weight, 9... Pulley, 10
...! f! Stone, 11... Pair magnet, 12.
...Suction pipe, 13...Suction nozzle, 14.
...Aqueous phase, 15...Carrier and substrate), 16...Carrier and F arm.

Claims (5)

[Claims] (1) A magnetic material layer is laminated on a substrate, and then an organic protective layer containing a polymerized monomolecular film of a polymerizable compound or a cumulative film thereof is formed thereon, and the resulting laminate is subjected to heat treatment and/or A method for manufacturing a magnetic recording medium, the method comprising performing vacuum treatment. (2) The manufacturing method according to claim 1, wherein an intermediate layer is provided between the organic protective layer and the magnetic layer. (3) The manufacturing method according to claim 1, wherein the organic protective layer has a thickness of 15 Å or more and 100 Å or less. (4) The manufacturing method according to claim 2, wherein the intermediate layer is a thin film of cobalt oxide. (5) The manufacturing method according to claim 1, wherein the substrate is an aromatic polyimide film.