JPS5917224A - Manufacture of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain the magnetic recording medium of high performance and excellent mass- productivity by controlling the forming density of a magnetic material by the surface density of a ligand and a metallic complex formed on a base body. CONSTITUTION:There are a process, in which a solution of the ligand containing the atoms of nitrogen, oxygen or sulfur and the metallic complex mainly comprising the ions of a metal selected from at least one of platinum family, such as platinum, iridium, rhodium, osmium, palladium, ruthenium, etc. is attached onto the base body and dried and said metallic complex is formed to a stratiform shape, and a process in which the ions of iron, nickel or cobalt or the like are reduced by a reducing atmosphere during the application of a magnetic field while using the metallic complex attached and formed onto said base body as nuclei for a reaction and the magnetic material mainly comprising iron, nickel or cobalt is formed onto said base body. The chelate type ligand consisting of an organic matter resulting from the unpaired electrons of the atoms of nitrogen N, oxygen 0 or sulfur S or the like is used. Since the surface density of the metallic complex and the ligand formed onto the base body can be controlled previously, the magnetic material formed after the ligand and the complex are formed grows gradually in proportional to the surface density of the ligand and the metallic complex. Accordingly, the method has an advantage which can easily control and prescribe the forming density of the magnetic material comparatively freely.

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 are made of gamma-ferric trioxide γ-
Fine acicular powder of a magnetic material such as Fe, 03 is mixed and dispersed in a polymer solution with a binder, and this solution is applied onto an electrically insulating substrate by a method such as a doctor blade method, and then dried. A dispersion coating method that forms a magnetic powder layer on a substrate; (b) A substrate activated by special chemical pretreatment is introduced and immersed in an electroless plating solution, and a magnetic layer is formed on the substrate by a chemical reaction. (iii) Vapor phase plating to form a magnetic layer on a substrate by vacuum deposition of a magnetic metal.

When the purpose is magnetic recording, extremely high uniformity and relatively large coercive force are used to increase the recording density.The fineness of the magnetic powder is required to improve the single-frequency characteristics, and large saturation and residual magnetic flux are used to improve the output characteristics. 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 is made small and the long axis t of the particles is made long. In other words, it is important to have a large acicular ratio t/r, (b) to orient the magnetic particles in the direction of magnetization, and (C) to form such magnetic particles thinly and uniformly on the substrate. becomes.

According to conventional manufacturing methods, for example, the dispersion solution coating method described in (a) above, even if magnetic particles with a large l/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 methods (0) and (c) above, L/
It is very difficult to form a magnetic material with a large r. Therefore, it is necessary to use a very special manufacturing method, which has the disadvantage of lacking mass productivity. Furthermore, the above (0)
In the electroless plating method, which is a manufacturing method for It had some disadvantages.

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 metal whose main components are a ligand containing a nitrogen, oxygen or sulfur atom and an ion of at least one metal selected from the platinum group such as platinum, iridium, rhodium, osnium, palladium, and ruthenium. A step of depositing and drying a solution of the complex onto a substrate to form the metal complex in a layered manner; and a step of applying iron, nickel, cobalt, etc. in a reducing atmosphere while applying a magnetic field using the metal complex deposited and formed on the substrate as a reaction nucleus. There is obtained a method for manufacturing a magnetic recording medium, which comprises the step of reducing the ions of the magnetic material to form a magnetic material containing iron, nickel, or cobalt as a main component on the substrate.

The method for manufacturing a magnetic recording medium according to the present invention has the following features. That is: I) As the material of the substrate, electrically insulating materials such as plastics and ceramics, or electrically conductive materials such as aluminum and 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.

l11) 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, 1) Preliminarily form the metal complex to be used and form it on the substrate. Formation methods include 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.

− Iron, using a metal complex on a solid substrate as a reaction nucleus.

In order to form a magnetic material containing nickel and cobalt as main components, a reaction that reduces ions containing iron, nickel, and cobalt as main components can be carried out using the following reducing atmosphere.

Sword 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).

(a) Atmosphere of a solution containing ions of metals or metal complexes more base than iron, nickel, and cobalt (reduction method based on differences in redox potential) (i) Atmosphere irradiated with light such as ultraviolet rays (photoreduction method).

) An atmosphere of reducing gases such as hydrogen gas.

Note that these reducing atmospheres are good when used alone, but good results can also be obtained using a combination of these reducing atmospheres.

Ligands that form metal complexes include halogens such as chlorine and bromine, cyanide, and inorganic ligands such as ammonium, as well as unpaired atoms such as nitrogen N, oxygen O, and sulfur S. The present invention is characterized by the use of a chelate-type ligand made of an organic substance based on electrons. The manner of coordination of this chelate type ligand varies depending on the metal species forming the complex, but O-0,0-N, O-0,0-N,
There are coordination types such as 0-8°N-N, N-8, and S-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 acetylacetone, dibenzoylmethane, 1.1 .1-Trifluoro-3-(2-thenoyl)acetone, ammonium salt of N-nitron phenylhydroxylamine, N-benzoyl-N-phenylhydroxylamine, 1-nitroso-
0-0 coordination type represented by 2-naphthol, 0-N coordination type represented by 8-quinolitool, α-benzoin oxime, etc., monothio dibenzoylmethane, 1,1
．． O-8 coordination type represented by 1-1-lifluoro-3-(2-thiothenoyl)acetone etc., N-N coordination type represented by dimethylglyoxime, α-benzyloxime, diphenylthiocarbazone etc. , N-8 coordination type such as 8-quinolinthiol, S-8 coordination type such as sodium salt and ammonium salt of diethyldithiocarbamic acid, and 1-(2-pyridylazo)-2 The O-N-N coordination type represented by -naphthol and the like, and the multidentate coordination type represented by BDTA and the like are effective.

When forming this type of ligand or metal complex on a substrate, it is possible to use only the ligand or metal complex, but a binder such as a polymer may be added to improve adhesion to the substrate. ■ 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 of creating a cross-linked polymer by complexing the ligand and metal Effective results were also obtained by methods using so-called bridging ligands, which form molecular weight complexes.

The present invention has the special feature that the formation density of the magnetic material can be controlled by the surface density of the ligand and metal complex formed on the substrate. The sensitivity and resolution accuracy of magnetic recording are significantly affected 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 the plating conditions such as the composition of the plating solution and the vapor deposition conditions, but the control method is extremely difficult and reproducibility has long been affected. In addition to the drawback that it 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, so that the magnetic material that is subsequently formed can be controlled depending on the surface density of the ligands and metal complexes. Since the magnetic material grows proportionally, it has the 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 the nucleus, a magnetic material with a large l/r can be obtained, and
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
It is also effective to include a metal element such as u.

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.

Although different from cobalt, the metal complex of the present invention can act as a kind of reaction catalyst and accelerate the growth reaction of the magnetic material. Furthermore, since the metal complex of the present invention functions as a nucleus for the growth reaction, it is hardly mixed into the growing magnetic chain.

Therefore, there is an advantage that a magnetic material having a predetermined composition with excellent magnetic properties can be formed with good reproducibility.

Hereinafter, the present invention will be explained in detail with reference to Examples.

[Example 1] 100 me of a 1M aqueous solution of palladium chloride PdC1 is prepared, and a buffer solution is added thereto to adjust the pH to 2-8. 0.0% of acetylacetone in this aqueous palladium solution.
Add 50 tnl of 1M benzene solution and stir and mix both solutions thoroughly to form acetylacetone P d (
The l[) complex is separated and formed. Polymethyl methacrylate is added to a benzene solution of acetylacetone P d (1116) separated from the aqueous phase and stirred thoroughly until dissolved. This solution is sprayed onto one side of a polyethylene terephthalate film and then blown with compressed air. Stretch the film, apply the benzene solution thinly and uniformly on the film, and dry.

In this way, acetylacetone Pd (
The films in which the I[)@ bodies were formed were placed in solutions with the compositions and concentrations shown in Table 1, and a magnetic field of about 10,000 e was applied under the reaction conditions shown in Table 1 to react for about 1 minute. I created a variety. After the reaction, each film sample was 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 under 8FM, 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 core. In addition, when a magnetic substance chained in a needle shape was taken out and analyzed by XMA, it was found that it had a composition 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, when the influence of the magnetic field applied during the growth reaction of the magnetic material was studied, good results were obtained in the range of at least 100 to 30,000 C, and around 10,000 e is preferable.

Table 1 Table 2 [Example 2] Rhodium chloride Rh C13 IM aqueous solution 100 m/W2
The pH was adjusted to 3-11 and 8 using a buffer solution, respectively. 1 M of 8 diquinolitools (oxine) in aqueous rhodium solutions with pH 3-11 and 8, respectively.
Add a chloroform solution and an 8% aqueous solution of sodium diethyldithiocarbamate and stir thoroughly.
- Rhodium complexes are formed in the organic phase of the Rh complex of the quinoli tool, and rhodium complexes of the diethyldithiocarbamic acid R and h complexes are formed in the aqueous solution. The n1he form of diethylcarbamine was extracted with isobutyl methyl ketone.

Polyvinyl formal and polyvinyl butyral were added to the chloroporum solution and isobutyl methyl ketone solution thus obtained, respectively, and the mixture was thoroughly stirred and mixed until dissolved. A film of polyethylene terephthalate is immersed in each of these solutions, and when dried, a thin layer of rhodium complex is uniformly formed on the film.

A film in which a rhodium complex has been formed is placed in a solution with the composition and concentration shown in Table 1, and a magnetic field of about 10,000 C is applied in the plane of the film in the direction of magnetization under the reaction conditions shown in Table 1 to cause a reaction. Immediately, a magnetic substance in the form of an acicular chain forms in the direction of magnetization, with the complex on the film serving as a nucleus. After the reaction, the magnetic material was washed with water and 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 4 [Example 3] Iridium Ir 1-(2-pyridylazo)-21-7
0.5M solution of tolu complex in chloroform.

and 0.5 of 8-quinolinthiol in palladium Pd.
M chloroform solutions are prepared, and polyvinyl butyral is added to each chloroform solution and thoroughly mixed and dissolved. After each solution is applied onto a sheet of polyethylene terephthalate, it is dried to form a complex of iridium and palladium on the sheet.

Each sheet with an iridium complex and a palladium complex formed thereon was placed in a solution as shown in h and 1 of Table 5, respectively, and a magnetic field of about 1000 was applied under the reaction conditions shown in Table 5.
0e was applied in the magnetization direction within the sheet plane to cause a reaction. 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 benzene solution of rhodium 8-quinolitool complex is prepared, and polymethyl methacrylate is added to the benzene solution and thoroughly mixed and dissolved.Polyethylene A film in which a metal complex was formed on a terephthalate film was placed in the liquid shown in Table 7, and a magnetic field of about 10,000 e was applied in the plane of the film in the direction of magnetization under the reaction conditions shown in Table 7 to cause a reaction. The core 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.
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 is required perpendicular to the film surface, applying a magnetic field perpendicular to the film surface not only during reaction but also during washing and drying produces the same effect as in the above embodiment, and the present invention 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 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 magnetic 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, a magnetic recording medium with excellent magnetic properties can be easily obtained.

(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 large t/r can be used, and therefore a magnetic recording medium with excellent performance such as coercive force and squareness ratio can be used.

Claims (1)

[Claims] 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 member of the platinum group such as platinum, iridium, rhodium, osnium, palladium, and ruthenium. A step of depositing and drying a solution on a substrate to form the metal complex in a layered manner; and a step of applying ions of iron, nickel, or cobalt in a reducing atmosphere while applying a magnetic field using the metal complex deposited and formed on the substrate as a reaction nucleus. 1. A method for manufacturing a magnetic recording medium, comprising the step of reducing a magnetic material containing iron, nickel, or cobalt as a main component on the substrate.