JP2007128607A - Magnetic recording medium, its manufacturing method, and magnetic recording and reading device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a magnetic recording layer by using coating method, wherein high density recording equal to or higher than that of the vapor deposition type is made possible with a very thin and uniform thickness at a size level of magnetic fine particles, for solving the problem that the manufacturing cost is low but high density recording is difficult in the case of a coating type magnetic recording medium, and the high density recording is comparatively easily attained but the manufacturing cost is high in the case of a vapor deposition type magnetic recording medium. <P>SOLUTION: The high density magnetic recording medium with high reliability, wherein the magnetic fine particles selectively accumulated in layers on the surface of a medium base body are mutually covalently bonded between layers via an organic coating film formed on the surfaces of the magnetic fine particles, without using a binder resin, is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a magnetic recording medium. More specifically, a single fine particle film or a single fine particle accumulation film made of magnetic metal or magnetic metal oxide that has been given thermal reactivity or photoreactivity, radical reactivity or ion reactivity on the surface is selectively formed as a recording layer. The present invention relates to a magnetic recording medium and a magnetic recording reader using the same.

  In the present invention, “magnetic fine particles” include magnetic metal fine particles, magnetic alloy fine particles, and magnetic metal oxide fine particles. The magnetic recording medium of the present invention includes a magneto-optical recording medium.

  Conventionally, magnetic recording media in which magnetic metal fine particles or magnetic metal oxide fine particles dispersed in a binder as a magnetic recording layer are coated and cured on the surface of a medium substrate, and magnetic metal or magnetic metal oxide is deposited on the surface of the medium substrate. The medium is commercially available.

  However, a magnetic film having a uniform thickness at a particle size level (hereinafter referred to as a magnetic recording layer) in which only one layer of magnetic fine particles is selectively arranged on the surface of the medium substrate or a film in which only one layer of magnetic fine particles is arranged is selectively selected. A magnetic recording medium having a magnetic recording layer accumulated as a magnetic recording layer, a manufacturing method thereof, and a magnetic recording reader using the same have not yet been developed or provided.

With a coating-type magnetic recording medium, the manufacturing cost is low, but high-density recording is difficult. On the other hand, with a vapor deposition type magnetic recording medium, high-density recording can be achieved relatively easily, but has the disadvantage of high manufacturing costs.
Also, no method has been proposed for forming a magnetic recording layer that is ultra-thin and has a uniform thickness at the size level of magnetic fine particles and can be compared with a vapor deposition type by using a coating method.

  The present invention uses magnetic fine particles (including magnetic nanoparticles), is as thin as a vapor-deposited magnetic metal film, has a uniform thickness at the size level of the magnetic fine particles, and is equivalent to a vapor-deposited magnetic recording medium without using a binder. An object of the present invention is to provide a magnetic recording medium, a method for manufacturing the same, and a magnetic recording reader using the magnetic recording medium, which have magnetic recording characteristics higher than that.

  A first invention provided as means for solving the above-mentioned problems is a first aspect in which a magnetic fine particle film selectively formed on the surface of the medium substrate as the magnetic recording layer is selectively formed on the surface of the medium substrate. The magnetic recording medium is covalently bonded to each other through one organic film and a second organic film formed on the surface of the magnetic fine particles.

Here, it is convenient for improving the adhesion of the magnetic fine particles that the first organic film formed on the surface of the medium substrate and the second organic film formed on the surface of the magnetic fine particles are different from each other.
In addition, it is convenient to improve durability when the covalent bond is a —N—C— bond formed by a reaction between an epoxy group and an imino group.
Further, when the first organic film selectively formed on the surface of the medium substrate and the second organic film formed on the surface of the magnetic fine particle are formed of a monomolecular film, the film thickness uniformity of the magnetic recording layer can be improved. It is convenient for improvement.

In the second invention, the surface of the medium substrate is brought into contact with a chemical adsorption solution prepared by mixing at least the first alkoxysilane compound, a silanol condensation catalyst, and a non-aqueous organic solvent to react the alkoxysilane compound with the surface of the medium substrate. Forming a first reactive organic film on the surface of the medium substrate and selectively processing it, or selectively forming the organic film, and condensing the magnetic fine particles with at least a second alkoxysilane compound and silanol Forming a second reactive organic film on the surface of the magnetic fine particles by dispersing in a chemical adsorption solution prepared by mixing a catalyst and a non-aqueous organic solvent and reacting the alkoxysilane compound with the surface of the magnetic fine particles; A step of bringing the fine magnetic particles coated with the second reactive organic film into contact with the surface of the medium substrate on which the first reactive organic film is selectively formed and reacting, and an extra second The reactive organic film coated with magnetic particles is a method of manufacturing a magnetic recording medium comprising a step of washing off.

  At this time, the surface of the medium substrate is brought into contact with a chemical adsorption solution prepared by mixing at least a first alkoxysilane compound, a silanol condensation catalyst, and a non-aqueous organic solvent, and the alkoxysilane compound and the surface of the medium substrate are allowed to react with each other. A step of forming a first reactive organic film on the surface of the substrate, and dispersing magnetic fine particles in a chemical adsorption solution prepared by mixing at least a second alkoxysilane compound, a silanol condensation catalyst, and a non-aqueous organic solvent. In the step of reacting the alkoxysilane compound and the surface of the magnetic fine particles to form the second reactive organic film on the surface of the magnetic fine particles, the medium substrate and the surface of the magnetic fine particles are washed with an organic solvent, respectively. It is convenient to form the first and second reactive monomolecular films covalently bonded to the film because the film thickness uniformity can be improved.

Further, the first reactive organic film contains an epoxy group and the second reactive organic film contains an imino group, or the first reactive organic film contains an imino group and the second reactive organic film When the film contains an epoxy group, the adhesion of the magnetic fine particles can be improved, which is convenient.
Furthermore, the first reactive monomolecular film contains an epoxy group and the second reactive monomolecular film contains an imino group, or the first reactive monomolecular film contains an imino group and the second reaction It is advantageous that the functional monomolecular film contains an epoxy group because a covalent bond can be easily generated.

According to a third aspect of the present invention, there is provided a magnetic recording medium in which magnetic fine particles selectively accumulated in the form of a layer as a magnetic recording layer are covalently bonded to each other through an organic coating formed on the surface of the magnetic fine particles. .
Here, there are two types of organic coatings formed on the surface of the magnetic fine particles, and the magnetic fine particles on which the first organic film is formed and the magnetic fine particles on which the second organic film is formed are alternately stacked. It is convenient because the manufacturing process can be simplified.
Moreover, when the first organic film and the second organic film react to form a covalent bond, it is convenient because the peel resistance can be improved.
Furthermore, when the covalent bond is a —N—C— bond formed by the reaction of an epoxy group and an imino group, it is advantageous that the peel resistance can be further improved.

  In the fourth invention, at least the surface of the medium substrate is brought into contact with a chemical adsorption solution prepared by mixing a first alkoxysilane compound, a silanol condensation catalyst, and a non-aqueous organic solvent to react the alkoxysilane compound with the surface of the medium substrate. Forming a first reactive organic film on the surface of the medium substrate and selectively processing it, or selectively forming the organic film, and at least a second alkoxysilane compound comprising the first magnetic fine particles And a silanol condensation catalyst and a non-aqueous organic solvent are mixed and dispersed in a chemical adsorption solution, and the alkoxysilane compound and the surface of the magnetic fine particles are reacted to form a second reactive organic film on the surface of the first magnetic fine particles. And a step of bringing the first magnetic fine particles coated with the second reactive organic film into contact with the surface of the medium substrate on which the first reactive organic film is formed and reacting Cleaning and removing the first magnetic fine particles coated with an extra second reactive organic film to form a first magnetic recording layer; and removing the second magnetic fine particles from at least a third alkoxysilane compound; A third reactive organic film is formed on the surface of the second magnetic fine particle by dispersing it in a chemical adsorption solution prepared by mixing a silanol condensation catalyst and a non-aqueous organic solvent, and reacting the alkoxysilane compound with the surface of the magnetic fine particle. The step of forming and contacting the second magnetic fine particles coated with the third reactive organic film on the surface of the medium substrate on which the first magnetic recording medium coated with the second reactive organic film is formed And a step of selectively forming a second magnetic recording layer by washing away and removing the second magnetic fine particles coated with an extra third reactive organic film. It is a manufacturing method.

At this time, if the first reactive organic film and the third reactive organic film are the same, it is convenient because the process can be simplified.
Further, after the step of forming the second magnetic recording layer, similarly, the step of forming the first magnetic recording layer and the step of forming the second magnetic recording medium are repeated, thereby controlling the film thickness of the recording layer. This is convenient.
Further, after the steps of forming the first to third reactive organic films, the medium substrate or the magnetic fine particle surface is washed with an organic solvent to be covalently bonded to the medium substrate or the magnetic fine particle surface, respectively. The formation of the monomolecular film is convenient for ensuring uniformity of the film thickness.
Furthermore, the first and third reactive organic films contain an epoxy group and the second reactive organic film contains an imino group, or the first and third reactive organic films contain an imino group and the second reactive organic film contains an imino group. When the reactive organic film contains an epoxy group, it is advantageous in improving the film adhesion.

In addition, when a ketimine compound, or an organic acid, an aldimine compound, an enamine compound, an oxazolidine compound, or an aminoalkylalkoxysilane compound is used in place of the silanol condensation catalyst, it is convenient to shorten the production time.
In addition, when a ketimine compound or at least one selected from an organic acid, an aldimine compound, an enamine compound, an oxazolidine compound, and an aminoalkylalkoxysilane compound is used as a co-catalyst for the silanol condensation catalyst, the production time can be further shortened. Convenient.
Furthermore, it is convenient to align the magnetic direction when the step of bringing the magnetic fine particles into contact with each other and performing the reaction in a magnetic field.

  According to a fifth aspect of the present invention, there is provided a first organic film formed on the surface of the medium substrate, and a second layer formed on the surface of the magnetic particles, wherein the magnetic particle layer is selectively formed on the surface of the medium substrate as a magnetic recording layer. A magnetic recording reader using a magnetic recording medium, wherein the magnetic recording medium is covalently bonded to each other via an organic film.

  According to a sixth aspect of the present invention, the magnetic recording layer is selectively accumulated on the surface of the medium substrate as a magnetic recording layer, and the magnetic fine particles are covalently bonded to each other through an organic film formed on the surface of the magnetic fine particles. A magnetic recording reader using a recording medium.

  According to the present invention, a high-performance magnetic recording medium having a magnetic recording characteristic equal to or higher than that of a vapor deposition type magnetic recording medium and a manufacturing method thereof can be provided at a low cost by using a wet method.

  In the present invention, at least the surface of the medium substrate is brought into contact with a chemical adsorption solution prepared by mixing a first alkoxysilane compound, a silanol condensation catalyst, and a non-aqueous organic solvent to react the alkoxysilane compound with the surface of the medium substrate. Forming a first reactive organic film on the surface of the medium substrate and selectively processing it, or selectively forming the organic film; and at least a second alkoxysilane compound and a silanol A second reactive organic film is formed on the surface of the first magnetic fine particle by dispersing it in a chemisorbed liquid prepared by mixing a condensation catalyst and a non-aqueous organic solvent and reacting the alkoxysilane compound with the surface of the magnetic fine particle. A step of bringing the first magnetic fine particles coated with the second reactive organic film into contact with the surface of the medium substrate on which the first reactive organic film is formed, and reacting with the medium. Cleaning and removing the first magnetic fine particles coated with the second reactive organic film to selectively form the first magnetic recording layer; and removing the second magnetic fine particles from at least a third alkoxysilane. Disperse in a chemical adsorption solution prepared by mixing a compound, a silanol condensation catalyst, and a non-aqueous organic solvent, and react the alkoxysilane compound with the surface of the magnetic fine particles to form a third reactive organic on the surface of the second magnetic fine particles. A step of forming a film, and a second magnetic fine particle coated with a third reactive organic film on the surface of the medium substrate on which the first magnetic recording medium coated with the second reactive organic film is formed And a step of selectively forming the second magnetic recording layer by washing and removing the second magnetic fine particles coated with the extra third reactive organic film. Magnetic fine particles are selectively accumulated in layers on the substrate surface. Child is to provide a magnetic recording medium which is covalently bonded to each other with an interlayer without binder resin through an organic film formed on the magnetic particle surface.

  Therefore, according to the present invention, a high-performance magnetic recording medium having a magnetic recording characteristic equal to or higher than that of a vapor deposition type magnetic recording medium and a magnetic recording reader using the same can be obtained easily and at low cost by using a wet method. There is an action that can be manufactured.

  Hereinafter, although the detail of this invention is demonstrated using an Example, this invention is not limited at all by these Examples.

  Further, the magnetic fine particles of the magnetic recording layer in the magnetic recording medium of the present invention include magnetic metal fine particles made of iron, chromium, nickel, and alloys thereof, ferrite, magnetite, chromium oxide, iron platinum (FePt) alloys, and the like. First, magnetite fine particles will be described as a representative example.

  First, a disk-shaped aluminum alloy medium substrate 1 was prepared and thoroughly dried. Next, 99 wt% of a chemical containing a functional group reactive at the functional site as a chemical adsorbent, for example, an epoxy group and an alkoxysilyl group at the other end, for example, a chemical represented by the following formula (Chemical Formula 1), a silanol condensation catalyst For example, dibutyltin diacetylacetonate or acetic acid, which is an organic acid, is weighed to 1% by weight, and a concentration of about 1% by weight in a magnetite solvent such as hexamethyldisiloxane solvent (preferably a chemical adsorbent) The chemical adsorption solution was prepared by dissolving so that the concentration of the solution was about 0.5 to 3%.

Next, the medium substrate 1 was immersed in this adsorbent and reacted in ordinary air (relative humidity 45%) for about 2 hours. At this time, in the the media substrate 1 surface has a great many hydroxyl groups 2 (FIG. 1 (a)), the chemical -Si adsorbent (OCH ₃₎ wherein the hydroxy group is a silanol condensation catalyst or an organic acid, Is reacted in the presence of acetic acid (in this case, de-CH ₃ OH) to form a bond represented by the following formula (Chemical Formula 2) and chemically bond to the surface over the entire surface of the medium substrate 1. A chemisorption monomolecular film 3 containing an epoxy group is formed with a film thickness of about 1 nanometer.

Here, when an adsorbent containing an amino group is used, since a precipitate is generated with a tin-based catalyst, it is better to use an organic acid such as acetic acid. The amino group contains an imino group, but substances containing an imino group in addition to the amino group include pyrrole derivatives and imidazole derivatives. Furthermore, when a ketimine derivative was used, an amino group could be easily introduced by hydrolysis after film formation.
Thereafter, when the substrate was washed with chloroform, which is a chlorinated solvent, the medium substrate 4 in which the electrode was covered with a chemically adsorbed monomolecular film having a reactive functional group, such as an epoxy group, on the surface could be produced. (Fig. 1 (b))

  Note that the reactivity is almost the same when taken out into the air without washing, but the chemical adsorbent remaining on the surface of the medium substrate reacts with the moisture in the air on the surface, and the chemical adsorption takes place on the surface. A medium substrate on which an extremely thin reactive polymer film made of an agent was formed was obtained.

Next, an excimer laser is used to selectively irradiate unnecessary portions of the substrate surface concentrically and remove the reactive monomolecular film by ablation (FIG. 1 (c)), or an epoxy group. Was opened and deactivated. (FIG. 1 (d)) That is, it was possible to manufacture the base materials 6 and 6 'on which the glass substrate surface was selectively covered in a pattern with concentric and linear coatings 5 and 5' having an epoxy group. .

  As another method, a cationic polymerization initiator, for example, Irgacure 250 manufactured by Ciba Specialty Chemicals Co., Ltd. is diluted with methyl ethyl ketone (MEK) and applied to the surface of the coating, and selectively exposed with far ultraviolet rays. It could be deactivated in a pattern by selectively ring-opening polymerization of epoxy groups. In addition, if a water-soluble resist pattern, for example, a novolak positive resist is applied in advance, and after exposure and development, a monomolecular film containing an imino group is formed in the opening, and the resist is removed after further exposing the entire surface. A monomolecular film containing an imino group could be selectively formed.

  In the same manner as in Example 1, first, magnetite fine particles 11 having a size of about 100 nm as magnetic fine particles were prepared and well dried. Next, as a chemical adsorbent, a functional functional group having a reactive functional group such as an epoxy group or imino group and an alkoxysilyl group at the other end, such as the above formula (Formula 1) or the following formula (Formula 3) 99% by weight of the drug shown and a silanol condensation catalyst, for example, dibutyltin diacetylacetonate is weighed to 1% by weight, and magnetite solvent such as hexamethyldisiloxane and dimethylformamide (50:50) mixed solvent is used. A chemical adsorption solution was prepared by dissolving to a concentration of about 1% by weight (preferably the concentration of the chemical adsorbent is about 0.5 to 3%).

Anhydrous magnetite fine particles 11 were mixed and stirred in the adsorbed liquid and reacted in ordinary air (relative humidity 45%) for about 2 hours. At this time, since there are many hydroxyl groups 12 on the surface of the anhydrous magnetite fine particles (FIG. 2A), the -Si (OCH ₃ ) group of the chemical adsorbent and the hydroxyl group are present in the presence of a silanol condensation catalyst. To deal with alcohol (in this case, de-CH ₃ OH) to form bonds as shown in the above formula (Chemical formula 2) or the following formula (Chemical formula 4), and chemically bond with the surface over the entire surface of the insulating fine particles. The chemisorption monomolecular film 13 containing the epoxy group or the chemisorption film 14 containing the amino group was formed with a film thickness of about 1 nanometer (FIGS. 2B and 2C). Here, the amino group includes an imino group. Examples of the substance containing an imino group in addition to an amino group include a pyrrole derivative and an imidazole derivative. Furthermore, when a ketimine derivative containing alkoxysilane was used, an amino group could be easily introduced by hydrolysis after the film formation.

Thereafter, chloroform, which is a chlorinated solvent, is added and washed with stirring. Then, magnetite fine particles 15 covered with a chemically-adsorbed monomolecular film having a reactive functional group, for example, an epoxy group on the surface, or a chemical having an amino group. The magnetite fine particles 16 covered with the adsorption monomolecular film could be respectively produced.

Note that this film was extremely thin with a nanometer-level film thickness, so the particle diameter was not impaired.
On the other hand, when taken out into the air without washing, the reactivity does not change substantially, but the chemical adsorbent remaining on the particle surface reacts with the moisture in the air by evaporation of the solvent, and the chemical adsorbent on the surface. Magnetite fine particles on which an extremely thin reactive polymer film was formed were obtained.

Next, magnetite fine particles 23 covered with the chemical adsorption monomolecular film having amino groups are dispersed in alcohol on the surface of the aluminum alloy medium substrate 22 selectively covered with the chemical adsorption monomolecular film 21 having the epoxy group. When heated to about 100 ° C., the amino groups on the surface of the magnetite fine particles that are in contact with the epoxy groups on the surface of the medium substrate are added by the reaction shown in the following formula (Chemical Formula 5) to form insulating fine particles. The media substrate is selectively bonded through two monolayers. At this time, when the alcohol was evaporated while applying ultrasonic waves, the film thickness uniformity of the coating could be improved.

そこで、再びアルコールで基材表面を洗浄し、余分で未反応のアミノ基を有する化学吸着単分子膜で被われたマグネタイト微粒子を洗浄除去すると、媒体基体表面でエポキシ基を有する化学吸着単分子膜に共有結合したアミノ基を有する化学吸着単分子膜で被われたマグネタイト微粒子２３を選択的に１層のみ並べた状態で、且つ粒子サイズレベルで均一厚みのパターン状のマグネタイト微粒子膜２４が形成できた。（図３（ａ））

Therefore, the substrate surface is again washed with alcohol, and the magnetite fine particles covered with the extra unreacted amino group chemically adsorbed monomolecular film are washed and removed. A magnetite fine particle film 24 having a uniform thickness at the particle size level can be formed in a state where only one layer of magnetite fine particles 23 covered with a chemisorbed monomolecular film having an amino group covalently bonded to is selectively arranged. It was. (Fig. 3 (a))

At this time, when the alcohol was evaporated while applying ultrasonic waves in a magnetic field, the uniformity of the coating could be improved.
Here, the thickness of the patterned single-layer insulating fine particle film of magnetite fine particles was about 100 nm.

On the other hand, when a film of magnetite fine particles covered with a chemisorption monomolecular film having an epoxy group is formed on the surface of an aluminum medium substrate covered with a chemisorption monomolecular film having an amino group, the chemical having an epoxy group Magnetite fine particles covered with the adsorption monomolecular film were covalently bonded in a state where only one layer was arranged on the surface of the aluminum medium substrate, and a magnetic recording layer having a uniform thickness at the particle size level could be formed.
Here, when the magnetite fine particles are needle-shaped or rod-shaped, when a solution is applied, a magnetic recording medium in which the direction of the magnetic moment of the magnetite fine particles constituting the magnetic recording layer is aligned is produced by applying and drying in a magnetic field. did it.
Needless to say, the thickness of the magnetic recording layer can be controlled by the particle size.

Further, when it is desired to increase the film thickness of the magnetite fine particle film, the magnetite fine particles covered with the chemically adsorbed monomolecular film having a covalently bonded amino group are arranged in a pattern in a single layer following Example 3, and Magnetite fine particles 25 covered with a chemisorbed monomolecular film having an epoxy group are dispersed in alcohol and applied to the surface of a medium substrate 22 on which a single-layer insulating fine particle film 24 having a uniform thickness at the particle size level is formed. Then, when heated to about 100 ° C., the epoxy groups on the surface of the magnetite fine particles in which the magnetite fine particles covered with the chemisorption monomolecular film having amino groups are in contact with the amino groups in the pattern-formed single layer are Magnetite added by the reaction shown in the formula (Chemical Formula 5) and covered with a chemisorbed monomolecular film having an amino group on the surface of the medium substrate Magnetite fine particles covered by the chemical adsorption monomolecular film having a particle and epoxy groups were selectively bound and solidified via the two monolayers.

Then, the surface of the base material is washed again with alcohol, and the magnetite fine particles covered with the extra unreacted epoxy group chemically adsorbed monomolecular film are removed by washing, whereby the second layer of magnetite fine particles covalently bonded to the electrode 20 is obtained. A patterned magnetite fine particle film 26 having a two-layer structure having a uniform thickness at a particle size level in a state where only one layer is arranged can be formed. (Fig. 3 (b))

Similarly, when magnetite fine particles 27 covered with a chemisorption monomolecular film having an amino group and magnetite fine particles 28 covered with a chemisorption monomolecular film having an epoxy group are alternately laminated as many times as necessary, magnetite fine particles having a multilayer structure are formed. The film 29 could be selectively accumulated, and a magnetic recording medium having an arbitrary thickness could be formed.

In the present embodiment, the case where a plurality of magnetite fine particle films are formed is shown, but the number of layers can be arbitrarily determined. Even the thinnest single-layered magnetite fine particle film was confirmed to function as a magnetic recording medium.
Further, when a magnetic recording reader was manufactured using this magnetic recording medium, a recording density equivalent to or higher than that of the vapor deposition type magnetic recording medium could be achieved.

  In Examples 1 and 2, the substance represented by the formula (Chemical Formula 1) or (Chemical Formula 3) was used as the chemical adsorbent containing a reactive group. The substance shown in (16) was available.

(1) (CH ₂ OCH) CH ₂ O (CH ₂ ) ₇ Si (OCH ₃ ) ₃
(2) (CH ₂ OCH) CH ₂ O (CH ₂ ) ₁₁ Si (OCH ₃ ) ₃
(3) (CH ₂ CHOCH (CH ₂ ) ₂ ) CH (CH ₂ ) ₂ Si (OCH ₃ ) _{3
(4) (CH 2 CHOCH (} CH 2) 2) CH (CH 2) 4 Si (OCH 3) 3
_{(5) (CH 2 CHOCH (} CH 2) 2) CH (CH 2) 6 Si (OCH 3) 3
_{(6) (CH2OCH) CH 2} O (CH 2) 7 Si (OC 2 H 5) 3
(7) (CH ₂ OCH) CH ₂ O (CH ₂ ) ₁₁ Si (OC ₂ H ₅ ) _{3
(8) (CH 2 CHOCH (} CH 2) 2) CH (CH 2) 2 Si (OC 2 H 5) 3
_{(9) (CH 2 CHOCH (} CH 2) 2) CH (CH 2) 4 Si (OC 2 H 5) 3
(10) (CH ₂ CHOCH (CH ₂ ) ₂ ) CH (CH ₂ ) ₆ Si (OC ₂ H ₅ ) ₃
(11) H ₂ N (CH ₂ ) ₅ Si (OCH ₃ ) ₃
(12) H ₂ N (CH ₂ ) ₇ Si (OCH ₃ ) ₃
(13) H ₂ N (CH ₂ ) ₉ Si (OCH ₃ ) ₃
(14) H ₂ N (CH ₂ ) ₅ Si (OC ₂ H ₅ ) ₃
(15) H ₂ N (CH ₂ ) ₇ Si (OC ₂ H ₅ ) ₃
(16) H ₂ N (CH ₂ ) ₉ Si (OC ₂ H ₅ ) ₃

Here, the (CH ₂ OCH) — group represents a functional group represented by the following formula (Formula 6), and the (CH ₂ CHOCH (CH ₂ ) ₂ ) CH— group is represented by the following formula (Formula 7). Represents a functional group.

  In Examples 1 and 2, silanol condensation catalysts include carboxylic acid metal salts, carboxylic acid ester metal salts, carboxylic acid metal salt polymers, carboxylic acid metal salt chelates, titanate esters, and titanate ester chelates. Is available. More specifically, stannous acetate, dibutyltin dilaurate, dibutyltin dioctate, dibutyltin diacetate, dioctyltin dilaurate, dioctyltin dioctate, dioctyltin diacetate, stannous dioctanoate, lead naphthenate, cobalt naphthenate , Iron 2-ethylhexenoate, dioctyltin bisoctylthioglycolate, dioctyltin maleate, dibutyltin maleate polymer, dimethyltin mercaptopropionate polymer, dibutyltin bisacetylacetate, dioctyltin bisacetyl Laurate, tetrabutyl titanate, tetranonyl titanate and bis (acetylacetonyl) dipropyl titanate could be used.

  As the solvent for the film forming solution, it is possible to use an organic chlorine-based solvent, a hydrocarbon-based solvent, a fluorinated carbon-based solvent, a magnetite-based solvent, or a mixture thereof that does not contain water. In addition, when it is going to raise particle concentration by evaporating a solvent, without wash | cleaning, the boiling point of a solvent is good at about 50-250 degreeC. Further, when the adsorbent is an alkoxysilane type and the organic film is formed by evaporating the solvent, an alcohol type solvent such as methanol, ethanol, propanol, or a mixture thereof can be used in addition to the solvent.

  Specifically usable are chlorosilane-based non-aqueous petroleum naphtha, solvent naphtha, petroleum ether, petroleum benzine, isoparaffin, normal paraffin, decalin, industrial gasoline, nonane, decane, kerosene, dimethyl magnetite, phenyl magnetite, alkyl modified Examples thereof include magnetite, polyether magnetite, and dimethylformamide.

  Fluorocarbon solvents include fluorocarbon solvents, Fluorinert (product of 3M), Afludo (product of Asahi Glass). These may be used alone in a single layer with a single pattern, or two or more may be combined as long as they are well mixed. Further, an organic chlorine solvent such as chloroform may be added.

  On the other hand, when a ketimine compound or organic acid, aldimine compound, enamine compound, oxazolidine compound, aminoalkylalkoxysilane compound is used instead of the above-mentioned silanol condensation catalyst, the treatment time is reduced to about half to 2/3 even at the same concentration. did it.

  Furthermore, a silanol condensation catalyst and a ketimine compound, or an organic acid, an aldimine compound, an enamine compound, an oxazolidine compound, and an aminoalkylalkoxysilane compound can be used in a range of 1: 9 to 9: 1. )), The processing time can be increased several times faster (up to about 30 minutes), and the film forming time can be reduced to a fraction of a minute.

  For example, dibutyltin oxide, which is a silanol catalyst, was replaced with H3 from Japan Epoxy Resin, which is a ketimine compound, and the other conditions were the same, but the reaction time was reduced to about 1 hour. Results were obtained.

  Furthermore, the silanol catalyst was replaced with a mixture of ketimine compound Japan Epoxy Resin H3 and silanol catalyst dibutyltin bisacetylacetonate (mixing ratio is 1: 1), and other conditions were the same. The same results were obtained except that the reaction time could be shortened to about 30 minutes.

  Therefore, the above results revealed that ketimine compounds, organic acids, aldimine compounds, enamine compounds, oxazolidine compounds, and aminoalkylalkoxysilane compounds are more active than silanol condensation catalysts.

  Furthermore, it was confirmed that the activity is further increased when one of a ketimine compound, an organic acid, an aldimine compound, an enamine compound, an oxazolidine compound, and an aminoalkylalkoxysilane compound is mixed with a silanol condensation catalyst.

  Here, the ketimine compound that can be used is not particularly limited. For example, 2,5,8-triaza-1,8-nonadiene, 3,11-dimethyl-4,7,10-triaza-3 , 10-tridecadiene, 2,10-dimethyl-3,6,9-triaza-2,9-undecadiene, 2,4,12,14-tetramethyl-5,8,11-triaza-4,11-pentadeca Diene, 2,4,15,17-tetramethyl-5,8,11,14-tetraaza-4,14-octadecadiene, 2,4,20,22-tetramethyl-5,12,19-triaza- 4,19-trieicosadiene and the like.

  Further, the organic acid that can be used is not particularly limited, but there are, for example, formic acid, acetic acid, propionic acid, lactic acid, malonic acid, and the like, which have almost the same effects.

  In Examples 1 to 4 described above, an example in which a magnetic recording layer is formed using magnetite fine particles has been described. However, the present invention can be any magnetic fine particles whose surface is oxidized except for iron platinum-based magnetic fine particles. Applicable to fine particles. Although a circular magnetic disk has been described as an example of the medium substrate, it goes without saying that the same applies to a tape-shaped medium substrate. Further, in Examples 1 to 4 described above, magnetite fine particles and a circular aluminum alloy medium substrate have been described as examples. However, the present invention includes active hydrogen on the surface, that is, hydrogen of a hydroxyl group, hydrogen of an amino group or imino group, and the like. However, any magnetic fine particle or medium substrate can be used as long as it is a magnetic fine particle or medium substrate.

Specifically, the magnetic fine particles of the magnetic recording layer include magnetic metal fine particles made of iron, chromium, nickel, and alloys thereof, and magnetic metal oxide fine particles made of ferrite, magnetite, chromium oxide, or the like. The medium substrate includes glass and aluminum. In the case of a synthetic resin such as an acrylic plate or a polycarbonate plate that does not contain active hydrogen on the surface, the method of the present invention can be applied if the surface is oxidized by corona treatment.

FIG. 2 is a conceptual diagram in which the reaction on the surface of the medium substrate in the first embodiment of the present invention is expanded to a molecular level, (a) is a diagram of the surface before the reaction, and (b) is a monomolecular film containing an epoxy group formed. (C) is a conceptual diagram showing a state in which the monomolecular film is processed by ablation, and (d) is a concept showing a state in which an epoxy group is selectively ring-opened and cross-linked by light irradiation. FIG. It is the conceptual diagram which expanded reaction of the magnetite fine particle surface in the 2nd Example of this invention to the molecular level, (a) is a figure of the magnetite fine particle surface before reaction, (b) is a monomolecular film containing an epoxy group (C) shows a view after a monomolecular film containing an amino group is formed. It is the conceptual diagram which expanded the reaction of the medium substrate surface in the 3rd and 4th Example of this invention to the molecular level, (a) is the figure of the base-material surface in which the single layer magnetite fine particle film | membrane was formed selectively, (B) shows a schematic cross-sectional view in which a plurality of layers and magnetite fine particle films are selectively laminated.

Explanation of symbols

1 Glass substrate 2 Hydroxyl group
3 Monomolecular film containing epoxy group
Patterned film having a glass substrate 5,5 'epoxy groups covered with a monomolecular film containing 4 epoxy groups
6 , 6 ′ Substrate selectively covered with a patterned film having an epoxy group 11 Magnetite fine particles 12 Hydroxyl group 13 Monomolecular film containing epoxy group 14 Monomolecular film containing amino group
Magnetite fine particles covered with a monomolecular film containing 15 epoxy groups
Magnetite fine particles covered with monomolecular film containing 16 amino groups 21 Chemical adsorption monomolecular film having epoxy groups 22 Glass substrate 23 Magnetite fine particles covered with chemical adsorption monomolecular films having amino groups 24 Patterned single layer magnetite Fine particle film 25 Magnetite fine particle covered with chemisorption monomolecular film having epoxy group
26 Two-layered patterned magnetite fine particle film 27 Magnetite fine particle covered with chemisorption monomolecular film having amino group 28 Magnetite fine particle covered with chemisorption monomolecular film having epoxy group
29 Patterned magnetite fine particle film of two-layer structure

Claims (22)

A first magnetic film selectively formed on the surface of the medium substrate and a second organic film formed on the surface of the magnetic particles are selectively formed on the surface of the medium substrate as a magnetic recording layer. A magnetic recording medium that is covalently coupled to each other. 2. The magnetic recording medium according to claim 1, wherein the first organic film formed on the surface of the medium substrate and the second organic film formed on the surface of the magnetic fine particle are different from each other. The magnetic recording medium according to claim 1, wherein the covalent bond is a —N—C— bond formed by a reaction between an epoxy group and an imino group. 3. The magnetism according to claim 1, wherein the first organic film selectively formed on the surface of the medium substrate and the second organic film formed on the surface of the magnetic fine particle are composed of a monomolecular film. recoding media. The surface of the medium substrate is brought into contact with a chemical adsorption solution prepared by mixing at least a first alkoxysilane compound, a silanol condensation catalyst, and a non-aqueous organic solvent, and the alkoxysilane compound and the medium substrate surface are reacted to form a surface on the medium substrate. Forming a first reactive organic film and selectively processing it, or selectively forming the organic film; and forming the magnetic fine particles into at least a second alkoxysilane compound, a silanol condensation catalyst, and a non-aqueous organic material. A step of forming a second reactive organic film on the surface of the magnetic fine particle by reacting the alkoxysilane compound with the surface of the magnetic fine particle by dispersing in a chemical adsorption solution prepared by mixing a solvent; A step of bringing the fine magnetic particles coated with the second reactive organic film into contact with the surface of the medium substrate on which the organic film is selectively formed, and reacting, and an extra second reactive property. Method of manufacturing a magnetic recording medium which comprises a step of washing and removing the magnetic fine particles coated with a film. The surface of the medium substrate is brought into contact with a chemical adsorption solution prepared by mixing at least a first alkoxysilane compound, a silanol condensation catalyst, and a non-aqueous organic solvent, and the alkoxysilane compound and the medium substrate surface are reacted to form a surface on the medium substrate. A step of forming a first reactive organic film, and a magnetic fine particle is dispersed in a chemical adsorption solution prepared by mixing at least a second alkoxysilane compound, a silanol condensation catalyst, and a non-aqueous organic solvent, and alkoxysilane In the step of forming a second reactive organic film on the surface of the magnetic fine particle by reacting the compound with the surface of the magnetic fine particle, the medium substrate and the surface of the magnetic fine particle are respectively washed with an organic solvent and covalently bonded to the surface of the medium substrate and the magnetic fine particle surface. 6. The method of manufacturing a magnetic recording medium according to claim 5, wherein the first and second reactive monomolecular films are formed. The first reactive organic film contains an epoxy group and the second reactive organic film contains an imino group, or the first reactive organic film contains an imino group and the second reactive organic film is 6. The method of manufacturing a magnetic recording medium according to claim 5, further comprising an epoxy group. The first reactive monolayer contains an epoxy group and the second reactive monolayer contains an imino group, or the first reactive monolayer contains an imino group and the second reactive monolayer The method for producing a magnetic recording medium according to claim 6, wherein the monomolecular film contains an epoxy group. A magnetic recording medium, wherein magnetic fine particles selectively accumulated in the form of a layer as a magnetic recording layer are covalently bonded to each other through an organic film formed on the surface of the magnetic fine particles. There are two types of organic coatings formed on the surface of the magnetic fine particles, and the magnetic fine particles on which the first organic film is formed and the magnetic fine particles on which the second organic film is formed are alternately laminated. The magnetic recording medium according to claim 9. The magnetic recording medium according to claim 10, wherein the first organic film and the second organic film react to form a covalent bond. The magnetic recording medium according to claim 9, wherein the covalent bond is a —N—C— bond formed by a reaction between an epoxy group and an imino group. At least the surface of the medium substrate is brought into contact with a chemical adsorption solution prepared by mixing the first alkoxysilane compound, the silanol condensation catalyst, and the non-aqueous organic solvent, and the alkoxysilane compound and the surface of the medium substrate are reacted to form the surface of the medium substrate. Forming a first reactive organic film and selectively processing it, or selectively forming an organic film; and forming the first magnetic fine particles into at least a second alkoxysilane compound, a silanol condensation catalyst, A step of forming a second reactive organic film on the surface of the first magnetic fine particle by dispersing it in a chemical adsorption solution prepared by mixing an aqueous organic solvent and reacting the alkoxysilane compound with the surface of the magnetic fine particle; A step of bringing the first magnetic fine particles coated with the second reactive organic film into contact with the surface of the medium substrate on which the first reactive organic film is formed and reacting, and an extra second Washing and removing the first magnetic fine particles coated with the responsive organic film to form a first magnetic recording layer; and removing the second magnetic fine particles from at least a third alkoxysilane compound, a silanol condensation catalyst, and a non-aqueous system. A step of forming a third reactive organic film on the surface of the second magnetic fine particle by dispersing it in a chemical adsorption solution prepared by mixing the organic solvent and reacting the alkoxysilane compound with the magnetic fine particle surface; A step of bringing the second magnetic fine particles coated with the third reactive organic film into contact with the surface of the medium substrate on which the first magnetic recording medium coated with the second reactive organic film is formed, and reacting the medium base surface. And a step of selectively forming a second magnetic recording layer by cleaning and removing the second magnetic fine particles coated with an extra third reactive organic film. Production method. 14. The method of manufacturing a magnetic recording medium according to claim 13, wherein the first reactive organic film and the third reactive organic film are the same. 14. The multilayer according to claim 13, wherein after the step of forming the second magnetic recording layer, the step of forming the first magnetic recording layer and the step of forming the second magnetic recording medium are repeated in the same manner. Method of manufacturing a magnetic recording medium having a structure. After the steps of forming the first to third reactive organic films, the surface of the medium substrate or the magnetic fine particles is washed with an organic solvent, and the first to third reactive units that are covalently bonded to the surface of the medium substrate or the magnetic fine particles, respectively. 14. The method of manufacturing a magnetic recording medium according to claim 13, wherein a molecular film is formed. The first and third reactive organic films contain an epoxy group and the second reactive organic film contains an imino group, or the first and third reactive organic films contain an imino group and the second reactivity 14. The method of manufacturing a magnetic recording medium according to claim 13, wherein the organic film includes an epoxy group. 14. The method for producing a magnetic recording medium according to claim 5, wherein a ketimine compound, or an organic acid, an aldimine compound, an enamine compound, an oxazolidine compound, or an aminoalkylalkoxysilane compound is used instead of the silanol condensation catalyst. 14. The method according to claim 5, wherein at least one selected from a ketimine compound or an organic acid, an aldimine compound, an enamine compound, an oxazolidine compound, and an aminoalkylalkoxysilane compound is used as a co-catalyst for the silanol condensation catalyst. A method for producing the magnetic recording medium according to claim. 14. The method of manufacturing a magnetic recording medium according to claim 5, wherein the step of causing the magnetic fine particles to contact and react is performed in a magnetic field. A magnetic fine particle film selectively formed as a magnetic recording layer on the surface of the medium substrate is mutually connected via a first organic film formed on the surface of the medium substrate and a second organic film formed on the surface of the magnetic fine particles. A magnetic recording reader using a magnetic recording medium, wherein the magnetic recording medium is covalently coupled. Magnetic recording using a magnetic recording medium characterized in that the magnetic fine particles are selectively accumulated on the surface of the medium substrate as a magnetic recording layer, and the magnetic fine particles are covalently bonded to each other through an organic film formed on the surface of the magnetic fine particles. Record reader.

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