JPS5996707A - 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 nucleus for reaction. CONSTITUTION:After the metallic complex whose main constituents are a ligand containing nitrogen, oxygen or sulfur atoms and metallic ions of a kind or more of tin, lead, copper, silver and gold 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 nucleus for reaction, and thus the magnetic substance whose main constituents are iron, nickel and cobalt is formed on said substrate. As the above-mentioned complex, for example, acetylacetone Pd(II) complex, etc. is used.

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
-Fe, 0. A fine needle-like powder of a magnetic substance such as the A dispersion coating method that forms a powder layer; (b) A method in which 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. Manufacturing methods such as electrolytic plating and vapor phase plating in which a magnetic layer is formed on a substrate by vacuum deposition of l/→magnetic metal are used.

For magnetic recording purposes, extremely high uniformity and relatively large coercive force are required to increase recording density, fineness of magnetic powder is required to improve frequency characteristics, and large saturated residual to improve output characteristics. Magnetic flux density is required. In order to satisfy this requirement with a certain type of magnetic material, (a) the short axis r of the magnetic particles should be made small, the long axis t of the particles should be made long, and the acicular ratio t/r should be large. It is important to (b) orient the magnetic particles in the magnetization direction, and (C) 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 t/r are used, it is difficult to coat and form magnetic particles thinly and uniformly on a substrate. has extremely difficult drawbacks. In addition, in the conventional manufacturing method (b) and method E9, s t
It is very difficult to form a magnetic material with a large /r. Therefore, since a very special manufacturing method must be used, there is a drawback that mass productivity is lacking. In addition, above (
In the electroless plating method, which is the manufacturing method of (b), the time required to form the magnetic material on the substrate, the time required, and the reaction rate are extremely low, and the magnetic material is formed randomly on the substrate. It had the disadvantage of poor magnetic properties.

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 whose main components are a ligand containing a nitrogen, oxygen or sulfur atom and an ion of a metal selected from at least one of tin, lead, copper, silver and gold is prepared. A step of depositing and drying the metal complex on the substrate to form a layer, a step of reducing the metal complex deposited on the substrate, and a reducing atmosphere while applying a magnetic field using the reduced metal complex as a reaction nucleus. A method for manufacturing a magnetic recording medium, comprising a step of reducing ions such as iron, nickel, and cobalt to form a magnetic material containing iron, nickel, and cobalt as main components on the substrate. can get.

The method for manufacturing a magnetic recording medium according to the present invention has the following features. That is, 1) The base material may be an electrically insulating material such as plastic or ceramic, or an electrically conductive material such as aluminum or copper.

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

111) 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, IV) Preliminarily form the metal 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.

a) 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) An 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.

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

Ligands that form metal complexes include, of course, halogens such as chlorine and bromine, cyanide, and ammonium, as well as nitrogen, nitrogen, and oxygen. The present invention is characterized by the use of chelate-type ligands based on unpaired electrons of atoms such as S and sulfur. The coordination method of the chelate type ligand varies depending on the metal species forming the complex, but Q-0,0
-N10-8. There are coordination types such as N-N%N-8%S-8. As in the present invention, when the metal of the complex is an iron group metal such as iron, nickel, and cobalt, as a ligand that forms a chelate complex with these metals, for example, acetylacetone, dibenzoylmethane, 1.1 .1-Trifluoro-3-(2-thenoyl)acetone, ammonium salt of N-nitrosophenylhydroxylamine, N-
○-○ coordination type represented by benzoyl-N-phenylhydroxylamine, 1-nitroso-2-naphthol, etc., O-N coordination type represented by 8-quinolitool, α-benzoin oximnato, monothio-di O-8 coordination type represented by benzoylmethane, 1.1.1-1-lifluoro-3-(2-thiothenoyl)acetone, etc.; represented by dimethylglyoxythi, α-benzyloxime, diphenylthiocarbazone, etc. N-N coordination type, represented by 8-quinolinthiol, etc., s-s coordination type, represented by sodium salts and ammonium salts of diethyldithiocarbamic acid, sotv tt4, etc. 1-(
Effective examples include the 0-N-N coordination type represented by 2-hyridylazo)-2-naphthol and the polydentate coordination type represented by EDTA.

When forming this type of ligand or metal complex on a substrate, it is possible to use only the ligand or metal complex, but in order to improve adhesion to the substrate, ■ A method of adding a binder such as a polymer. , ■ 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 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 a polymer, Effective results were also obtained by methods using so-called bridging ligands that form complexes.

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. What is the sensitivity and accuracy of magnetic recording?

It is significantly affected by the formation density of the magnetic material 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 the plating conditions such as the composition of the plating solution and the vapor deposition conditions, but the control method is extremely difficult and has poor reproducibility. In addition to the disadvantage of being 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 ligand and metal complex formed on the substrate can be controlled in advance. Since the magnetic material grows proportionally, there is an advantage that the formation density 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 a core, a magnetic material with a high acicular ratio can be obtained, and the growth direction is also 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
It is also effective to include metal elements such as.

According to the present invention, the metal of the metal complex used is different from iron, nickel, and cobalt, which are the main constituent elements of the magnetic material to be formed, but the metal complex of the present invention acts as a kind of reaction catalyst to form the magnetic material. The growth reaction can be accelerated. Furthermore, since the metal complex of the present invention functions as a nucleus for the growth reaction, it hardly mixes into the growing magnetic chain. For this reason,
There is an advantage that a magnetic material having a predetermined composition with excellent magnetic properties can be formed with good reproducibility.

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

[Example 1] 100 ml of a 1M aqueous solution of 5 nct of tin chloride is prepared, and a buffer solution is added thereto to adjust the pH to 5-6. When 50 mt of a 0.1M benzene solution of acetylacetone is added to this aqueous tin solution and the two solutions are thoroughly stirred and mixed, an acetylacetone 8 n (If) complex is separated and formed in the benzene phase. Acetylacetone 5n (
1) Add polymethyl methacrylate to the benzene solution of the complex and stir thoroughly until dissolved. This solution is sprayed onto one side of the film with a thickness of approximately 20 μm, and then casted with compressed air to coat the film thinly and uniformly with the benzene solution, and then dried. In this way, the film in which the metal complex of acetylacetone was formed was heated to a pH of 0,
It is immersed in a 5M sodium hypophosphite aqueous solution, a hydrazine aqueous solution, and a sodium borohydride aqueous solution adjusted to pH 4. In either case, the metal complex on the film is reduced and the coloring of the metal complex disappears. In addition to the method of immersing the metal complex in a reducing solution as described above, the reduction reaction of the metal complex was carried out by spraying the reducing solution onto the metal complex on the film, 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 with the composition and concentration shown in Table 1, and a magnetic field of about 10,000 e was applied under the reaction conditions shown in Table 1.
was applied for about 1 minute, and four types of film samples were prepared. After the reaction, each film sample was taken out, thoroughly washed with water, and dried. Note that the magnetic field was always applied so that it was 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 under 8EM, it was found that the magnetic particles were oriented and grown in the magnetization direction in a state in which the magnetic particles were arranged in a needle-like manner with the metal complex on the film as a core. In addition, by removing the needle-shaped magnetic material,
Analysis revealed 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.

Further, when the influence of the magnetic field applied during the growth reaction of the magnetic material was investigated, good results were obtained at least in the range of 100 to 30,000 e.

Table 1 Table 2 [Example 2] Two 100 mt IM aqueous solutions of lead chloride PBC4 were prepared,
pH 6-10 and 9-10 by buffer solution, respectively.
Adjust to 0.0% of 8-quinolitool (oxine) was added to lead aqueous solutions with pH values of 6 to 10 and 9 to 10, respectively.
A 1M chloroform solution and a 0.1M chloroform solution of diphenylthiocarbazone are added and stirred sufficiently to form a copper complex in the organic phase. Polyvinyl polymer and polyvinyl butyral were added to each of the chloroform solutions thus obtained, and the mixture was sufficiently stirred and mixed until dissolved. A polyethylene terephthalate film is immersed in each of these solutions, and when dried, a thin layer of lead complex is uniformly formed on the film.

When the film on which the lead complex was formed was irradiated with a 5 kW ultra-high pressure mercury lamp for about 3 Qsec, the complex color disappeared and the lead complex 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 100,006 mm 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. After the reaction, the composition and magnetic properties of the magnetic material were measured in the same manner as in Example 1 after washing with water and drying.
3 Table 4 Table 4 [Example 3] A 0.1M solution of dimethylglyoxime complex of gold (Au) and a 0.1M chloroform solution of diphenylthiocarbazone of silver (Ag(1)) were prepared, respectively. Then, polyvinyl butyral and ant-2-quinone were added to each chloroform solution and thoroughly mixed and dissolved. After each coating solution is applied onto a polyethylene terephthalate sheet, it is dried to adhere and form a gold and silver complex on the sheet.

6kW on a sheet on which gold and silver metal complexes are attached and formed
An exposure dose of approximately 300 mJ/cm'' was applied using a mercury lamp.

Due to the sensitizing action of anthraquinone, each metal complex is immediately reduced and decolored.

Each sheet on which the reduced metal complex was attached and formed was placed in a solution as shown in Table 5, and a magnetic field of approximately 10θOOe was applied in the direction of magnetization within the plane of the sheet to react under the reaction conditions shown in Table 5. Ta. After the reaction, it was thoroughly washed with water and dried.

The composition of the magnetic material was analyzed by XMA and the magnetic properties were measured in the same manner as in Examples, and the results are shown in Tables 5 and 6.

Table 6 [Example 4] A 1M chloroform solution of copper (1,1,1-trifluoro-3-(2-thiotenoyl)acetone complex) was prepared,
Polymethyl methacrylate is added to this 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.

A formaldehyde solution was applied to the film on which the metal complex was formed, and when the film was irradiated with ultraviolet light around 380 nm using an ultra-high pressure mercury lamp, the complex color disappeared and the metal complex was reduced. The film in this state was placed in the solution shown in Table 7, and a magnetic field of about 100,006 mm was applied in the plane of the film in the direction of magnetization to cause a reaction under the reaction conditions shown in Table 7. After the reaction, it was thoroughly washed with water and dried.

The composition and magnetic properties of the magnetic material were measured in the same manner as in Example 1, and the results are shown in Table 8.

Table 7 Table 8 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 embodimentsb, and the present invention is capable of perpendicular recording. It has been proven that this method is also extremely effective for magnetic recording media of this type.

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

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

(2) Since the @-type substance grows using the metal complex on the substrate as a reaction nucleus, the density of the magnetic substance on the substrate can be easily controlled by the surface density of the metal 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. Therefore, a magnetic material with a high acicular ratio is formed, and therefore a magnetic recording medium with excellent performance such as coercive force and squareness ratio can be obtained.

Procedural Amendment (Import) Director General of the Patent Office 1, Indication of Case 1981 Patent Application No. 2067
No. 42 No. 2, Title of the invention: Method for manufacturing magnetic recording medium 3
, Relationship with the case of the person making the amendment Applicant: 33-1 Shiba 5-chome, Minato-ku, Tokyo (423) NEC Corporation Representative: Tadahiro Sekimoto 4, Agent Address: 37-8 Shiba 5-chome, Minato-ku, Tokyo 108 No. Resident Mita Building 5, cane of "detailed description of the invention" in the specification subject to amendment.

6. Contents of the amendment (1) On page 7, lines 10-11, "iron group such as iron, nickel, and cobalt" was corrected to "tin, re, copper, silver, and gold, etc."

(2) On page 8, line 1, "11-1 refluoro" was corrected to "1-trifluoro."

(3) Added "of polyethylene terephthalate film" before "on one side" on page 11, line 8.

(4) In the first line of Example 4 on page 19, replace “copper (1)” with “
Corrected to ``Bronze 1''.

Claims (1)

[Claims] Ligands containing nitrogen, oxygen or sulfur atoms and tin, lead,
a step of depositing and forming a metal complex containing ions of a metal selected from at least one of copper, silver, and gold in a layered manner; a step of reducing the metal complex deposited and formed on the substrate; A method for manufacturing a magnetic recording medium, comprising the step of forming a magnetic material mainly composed of iron, nickel, and cobalt in a reducing atmosphere while applying a magnetic field using a metal complex as a reaction nucleus.