JPS5996705A - Manufacture of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium which has high performance and is excellent in mass productivity by forming a magnetic substance, whose main constituents are iron, nickel and cobalt, on a substrate with reduction atmosphere during impressing an electric field with a specific metallic complex deposited on the substrate and reduced as the core for reaction. CONSTITUTION:After the metallic complex whose main constituents are a ligand containing nitrogen, oxygen or sulphur atoms and metallic ions of a kind or more of iron, nickel and cobalt is deposited and formed in layer form on the substrate, the metallic complex on the substrate is reduced, Next, the ions of iron, nickel and cobalt are reduced with the reduction atmosphere during impressing the electric field with the reduced metallic complex as the core for reaction, and thus the magnetic substance whose main constituents are iron, nickel and cobalt is formed on said substrate. The above-mentioned ligand is e.g. acetylacetone, 8-quinolinol, alpha-benzyl oxime, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a magnetic recording medium, and particularly to a method of manufacturing a magnetic material used for magnetic recording such as a magnetic tape, a magnetic disk, and a magnetic card on a substrate.

Conventionally, magnetic recording media use (a) gamma - ferric trioxide γ
- Fine acicular powder of magnetic material such as FezO3 is mixed and dispersed in a solution of polymer as a binder, this solution is applied onto an electrically insulating substrate by a method such as a doctor blade method, and then dried and applied onto the substrate. (b) A substrate activated by special chemical pretreatment is introduced into an electroless plating solution and immersed, and a magnetic layer is formed on the substrate by a chemical reaction. (c) Vapor-phase plating method in which magnetic seeds are formed on the substrate by vacuum deposition of a magnetic metal. Extremely high uniformity and relatively large coercive force 9 Fineness of magnetic powder is required to improve frequency characteristics, and large saturated residual magnetic flux density is required to improve output characteristics. In order to satisfy this requirement with a certain type of magnetic material, (a) the short axis r of the magnetic particles should be small, the long axis l of the particles should be long, and the acicular ratio l/γ should be large; (b) It is important to orient the magnetic particles in the magnetization direction and (C1) to form such magnetic particles thinly and uniformly on the substrate.

According to conventional manufacturing methods, for example, the dispersion solution coating method described in (a) above, even if magnetic particles with a large l/γ are used, it is not possible to coat and form magnetic particles thinly and uniformly on a substrate. has extremely difficult drawbacks. In addition, in the conventional manufacturing method described above (l/γ
It is extremely difficult to form a magnetic material with a large
In the electroless plating method, which is the manufacturing method for (b), the time required to form the magnetic material on the substrate, that is, the reaction rate, is extremely low. It had the disadvantage of inferior characteristics.

An object of the present invention is to provide a method for manufacturing a magnetic recording medium that eliminates such conventional drawbacks and has high performance and excellent mass productivity.

According to the present invention, a solution of a metal complex mainly composed of a ligand containing nitrogen, oxygen, or sulfur atoms and ions of a metal selected from at least one of iron, nickel, and cobalt is deposited on a substrate.・A step of drying and forming the metal complex in a layered manner; a step of reducing the metal complex adhered and formed on the substrate; and a step of reducing iron, iron, By reducing ions such as nickel and cobalt, iron and
A method for manufacturing a magnetic recording medium is obtained, which includes a step of forming a magnetic material containing nickel and cobalt as main components.

The method for manufacturing a magnetic recording medium according to the present invention has the following features. That is: 1) As the material of the substrate, an electrically insulating material such as plastic or ceramics, or a electrically conductive material such as aluminum or copper can be used.

11) A metal complex is formed on a substrate, and magnetic particles can be grown using this as a reaction nucleus.

1ii) When growing magnetic particles, a magnetic field can be used to control the needle-like formation and orientation of the growing magnetic particles.

The above three are the basic features of the present invention, but the following methods are added to make these features more effective. That is, tv) Preform the whole island complex to be used and form it on the substrate. The formation method includes applying a solution of the metal complex onto the substrate by methods such as spraying, casting, or printing, or using a solution such as immersing the substrate in the solution of the metal complex. In this case, it is also effective to add a polymer or the like as a binder to improve the adhesion of the metal complex to the substrate. In addition, it is also effective to form the metal complex by methods such as vapor deposition and sputtering.

(2) The method of reducing the metal complex deposited on the substrate can be carried out using the following reducing atmosphere.

Power Sodium hypophosphite, Sodium borohydride,
Atmosphere of a solution containing reducing agents such as dimethylamine borane, diethylamine borane, hydrazine, formaldehyde, glucose, Rochelle's salt, formic acid, etc. (chemical reduction method).

b) A solution atmosphere containing ions of metals or metal complexes less base than iron, nickel, and cobalt (reduction method based on differences in redox potential).

~ 1) Light irradiation atmosphere using ultraviolet rays (photoreduction method).

Engineering) Atmosphere of reducing gas such as hydrogen gas.

Note that although these reducing atmospheres are good when used alone, good results can also be obtained by a method using a reducing atmosphere in combination with each other.

vD The reduction reaction is a process in which ions such as iron, nickel, and cobalt are reduced while a magnetic field is applied using the reduced metal complex as a reaction nucleus to form a magnetic material mainly composed of iron, nickel, and cobalt on a substrate. , can be carried out using the same reducing atmosphere as in V) above.

Ligands that form metal complexes include chlorine, odor
The present invention is characterized by the use of chelate-type ligands based on unpaired electrons of atoms such as nitrogen (N), oxygen (O), and sulfur (S), although they naturally include sodium halogens, cyanide, and ammonium salts. The manner of coordination of this chelate type ligand is 0-0.0-N, although it varies depending on the metal species forming the complex.

There are coordination types such as 0-8, N-N, N-8, and 8-8.

As in the present invention, when the metal of the complex is an iron group metal such as iron, nickel, and cobalt, examples of the ligand that forms a chelate complex with these metals include acetylacecentone and dibenzoylmethane.

1.1.1-Trifluoro-3-(2-thenoyl)acetone, ammorum salt of N-nitrone phenylhydrokylamine, N-benzoyl-N-7enylhydroxolamine, 1-nitrone-2- O-0 coordination type represented by naphthol etc., 0-N coordination type represented by 8-quinolitool, α-benzoin oxime etc., monothio-dibenzoylmethane, 1,1.1-trifluoro-3
-O- represented by (2-thiothenoyl)acetone etc.
8-coordinated dimethylglyoxime, α-benzyloxime.

N-N coordination type such as diphenylthiocarbazone, N-8 coordination type such as 8-quinolinthiol, and S-8 coordination type such as sodium salt and ammonium salt of diethyldithiocarbamic acid. position type, etc.
Effective examples include the 0-N-N coordination type represented by 1-(2-pyridylazo)-2-su7doldo, and the multidentate coordination type represented by EDTA.

When forming this type of ligand and metal complex on a substrate, it is possible to use only the ligand and gold halide, but in order to improve adhesion to the substrate, a binder such as a polymer is added. Methods: ■ A method using a so-called coordination polymer, in which a certain type of compound with a coordination function is attached to the main chain or side chain of the polymer, ■ A cross-linked type of high molecular weight by complex formation of a ligand and a metal. Effective results were also obtained by methods using so-called bridging ligands, which form complexes of .

The present invention is characterized in that the formation density of the magnetic material can be controlled by the surface density of the ligand or metal complex formed on the substrate. The sensitivity and resolution accuracy of magnetic recording are significantly influenced by the density of magnetic material formed on the substrate.

In conventional manufacturing methods such as normal electroless plating and vapor deposition methods, the density of magnetic material formed is controlled by plating conditions such as plating solution composition and vapor deposition conditions, but the control method is extremely difficult to reproduce. In addition to the disadvantage that it lacks properties and is difficult to mass-produce, the magnetic properties of the formed magnetic material are also relatively poor. However, according to the present invention, the surface density of the ligands and metal complexes formed on the substrate can be controlled in advance. Since the magnetic material grows proportionally, it has the advantage that the degree of formation of the magnetic material can be controlled and defined relatively freely. Furthermore, according to the present invention, since the magnetic material grows with the metal complex as the nucleus and L7, a magnetic material with a large acicular ratio can be obtained, which is 1.
Since the growth direction is one-dimensionally regulated and oriented by a magnetic field, a magnetic material with excellent magnetic properties can be formed.

According to the present invention, the formed magnetic material is mainly composed of ferromagnetic metals such as iron, nickel, and cobalt, or alloy compositions of these metals, but the magnetic material has mechanical properties such as magnetic properties and wear resistance. In order to improve the performance, nonmetallic elements such as phosphorus P, boron B, and longevity, tungsten W, manganese Mn, rhenium Re, and tin Sn are used.

It is also effective to include metal elements such as zinc Zn, vanadium V, and copper Cu.

According to the present invention, the metal of the metal complex used is iron or nickel, which is the main component element of the magnetic material to be formed.

Because it is the same metal as cobalt, 1) the magnetic material can easily grow with the metal complex as the nucleus, 2) the composition of the magnetic material can be easily controlled, 1) the resulting magnetic material has good magnetic properties. There are advantages such as:

The present invention will be explained in detail below using examples.

〔Example〕

A 100 mA' IM aqueous solution of nickel chloride NiCl2 is prepared, and a buffer solution is added thereto to adjust the pH to 5-6. 0.1M of acetylacetone in this nickel aqueous solution
When 50 ml of benzene solution is added and both liquids are sufficiently stirred and mixed, an acetylacetone N1(n) complex is separated and formed in the benzene phase. Acetylacetone N separated from aqueous phase
i (Add methyl polymethacrylate into a benzene solution of Ill complex and stir thoroughly until it dissolves. Spray this solution onto one side of a polyethylene terephthalate film with a film thickness of 20 μm, and then cast with compressed air. death,
Apply the benzene solution thinly and evenly on the film and dry.

In this way, the film in which the metal complex of acetylacetone was formed was mixed with a 0.5 M aqueous sodium hypophosphite solution and a hydrazine aqueous solution adjusted to pH 6, and
4 in an aqueous solution of sodium borohydride. In either case, the metal complex on the film is reduced and the coloring of the metal complex disappears. For the reduction reaction of the whole island complex, in addition to the method of immersing it in the reducing solution as described above, the method of spraying the reducing solution onto the metal complex on the film was carried out, but in both cases, the reduction of the metal complex was difficult. Admitted.

After reducing the metal complex on the film as described above, the film was placed in a solution having the composition and concentration as shown in Table 1, and a magnetic field of 10,000' was applied under the reaction conditions as shown in Table 1.
E was applied to react for about 1 minute, and four types of film samples were prepared. The reaction ridge and each film sample were taken out, thoroughly washed with water, and dried. Note that the direction of application of the magnetic field was always parallel to the magnetization direction at the time of evaluating the magnetic properties within the plane of the film. As a result of observing each film sample with an SEM, it was found that the magnetic particles were oriented and grown in the magnetization direction in a state in which magnetic particles were chained in an acicular shape with the metal complex on the film as a nucleus. In addition, we took out a magnetic substance chained in a needle shape and
When analyzed by MA, it was found that the composition was as shown in Table 2. Next, the magnetic properties of each sample were measured, and the results showed good properties as shown in Table 2.

In addition, we investigated the influence of the magnetic field applied during the growth reaction of the magnetic material, and found that it was at least 100 to 30,000e. 9-10 and 5
Adjust to ~10. When a 1fl toluene solution of monothio dibenzoylmethane and a 1M chloroform solution of 8-quinolitool (Oxino) are added to cobalt aqueous solutions with pHs of 9-10 and 5-10, respectively, and stirred thoroughly, a cobalt complex is added to the organic phase. It is formed. Add polystyrene and polyvinyl butyral to the carbon tetrachloride solution and chloroform solution, respectively, and stir and mix thoroughly until dissolved. A film of polyethylene terephthalate is immersed in each of these solutions and when dried, a thin layer of cobalt complex is uniformly formed on the film.

When the film on which the cobalt complex was formed was irradiated with a 5 KW ultra-high pressure mercury lamp for about 3 Q seconds, the complex color disappeared and the cobalt was reduced. When the film in this state is placed in a solution with the composition and concentration shown in Table 1, and a magnetic field of approximately 10,000 e is applied in the film plane in the direction of magnetization under the reaction conditions shown in Table 1, the film immediately changes. With the above complex as a core, a magnetic substance in the form of an acicular chain is formed in the direction of magnetization. The reaction edge was washed with water, dried, and the composition and magnetic properties of the magnetic material were measured in the same manner as in Example 1. As a result, the values shown in Tables 3 and 4 were obtained.

Table 3 Table 4 [Example 3] 400 ml of an aqueous solution of nickel chloride NiC4 and α-penzyldioquine IM was prepared, and the pH was adjusted to 8 to 1 using a buffer solution.
Adjust to 1. This aqueous solution of chloroform is 100m7! When added and thoroughly mixed and stirred, the nickel complex is extracted into the organic phase. Add polymethyl methacrylate and anth-2quinone to the chloroform solution and stir thoroughly until dissolved. This solution is applied onto a polyethylene terephthalate sheet and dried to form a nickel complex on the sheet.

The sheet on which the nickel complex was attached and formed was irradiated with an exposure amount of about 3 oomJ/cIrL2 using a 6 KW mercury lamp.

Sensitizing effect of anthraquinone The nickel complex is immediately reduced and loses its color. Reduced nickel complex force: The adhered sheet is placed in a liquid as shown in Table 5, and a magnetic field of about 10,000 e is applied under the reaction conditions shown in Table 5.
The reaction was carried out in the magnetization direction within the t-sheet plane. After the reaction, it was thoroughly washed with water and dried.

The composition and magnetic properties of the magnetic material are shown in Tables 5 and 6 in the same manner as in Example 1.

Table 5 Table 6 [Example 4] Iron 1-(2-pyridylazo)-2-naratol complex O
An IM benzene solution is prepared, and polymethyl methacrylate is added to the Hensen solution and thoroughly mixed and dissolved. This solution is cast onto a polyethylene terephthalate film and then dried to uniformly form a metal complex on the film.

When a formaldehyde solution was applied to the film on which the metal complex was formed and the film was irradiated with ultraviolet rays around 380 nm using an ultra-high pressure mercury lamp, the lead color disappeared and the metal complex was reduced.

The film in this state was placed in the liquid shown in Table 7.
Under the reaction conditions shown in the table, a magnetic field of about 10,000 e was applied in the film plane in the direction of magnetization to cause a reaction. After the reaction, it was thoroughly washed with water and dried.

Table 7 shows the composition and magnetic properties of the magnetic material in the same manner as in Example 1. In all of the above examples, the magnetic field applied during the reaction was parallel to the plane of the film. When magnetization perpendicular to the film surface is required, applying a magnetic field perpendicular to the film surface not only during the reaction but also during washing and drying can produce the same effect as in the above embodiment. It has been proven that this method is also extremely effective for magnetic recording media.

As described above, the present invention has the following effects compared to the conventional manufacturing method.

(1) Due to the catalytic action of the metal complex, the growth reaction of the magnetic material on the substrate is fast and the adhesion of the magnetic recording medium is excellent.

(2) Since the magnetic substance grows using the metal complex on the substrate as a reaction nucleus, the bitterness of the magnetic substance on the substrate can be easily controlled by the surface density of the gold bridge complex. Therefore, magnetic recording media with excellent magnetic properties can easily be found.

(3) Since the growth direction of the magnetic material can be regulated by a magnetic field, a chain of magnetic materials oriented in a -dimensional direction can be obtained. For this reason, a magnetic material with a large acicular ratio is formed,
Therefore, magnetic recording media with superior performance such as coercive force and squareness ratio can be replaced.

Procedural amendment (voluntary) Commissioner of the Patent Office 1, Indication of case 1981 Patent Application No. 2067
40 No. 2, Title of the invention: Method for manufacturing magnetic recording medium 3
, Relationship to the case of the person making the amendment Applicant: 5-33-1 Shiba, Iwa-ku, Tokyo (423) Representative: Tadahiro Sekimoto 4, Agent: 5-37 Shiba, Minato-ku, Tokyo 108 No. 8 Sumitomo Sanda Building 5 "Detailed Description of the Invention" column of the specification subject to amendment.

6. Contents of amendment (1) On page 7, lines 1-4, "ammorum" was corrected to "1 ammonium".

(2) Corrected "Nafdol" in line 7 of page 8 to "Naftol".

(3) On page 9, line 6, “lack” was corrected to “scarce.”

(4) Corrected “liquid dissolution” in line 2 of page 11 to “dissolution”.

(5) “Sakego Sodium” in column C of Table 1 on page 13 is 1
Corrected to ``Sodium Tartrate.''

(6) “Adjustment” in line 4 of page 14 was corrected to “adjustment”.

(7) Added “ni” after “aqueous solution” in the third line of Example 3 on page 16.

(8) “Naphthol” in line 2 of page 19 is “naphthol”
Corrected.

(9) Corrected "1 terephthalate" in line 5 of the same page to "terephthalate."

(11) In column j of Table 7 on page 20, write ro, o 1 * 0.2.0.1 in the blank space below 0.09J from top to bottom.
5.0.50 Added in the order of J.

Claims (1)

[Claims] Ligand iron containing nitrogen, oxygen or sulfur atoms. A step of depositing and forming a metal complex mainly composed of ions of a metal selected from at least one of nickel and cobalt, a step of reducing the metal complex deposited and formed on the substrate, and a step of reducing the reduced metal complex. A step of reducing ions such as iron, nickel, and cobalt in a reducing atmosphere while applying a magnetic field as a reaction nucleus to form a magnetic material mainly composed of iron, nickel, and cobalt on the substrate. A method of manufacturing a magnetic recording medium, comprising: