JPH02225534A - Ultra-thin inorganic particle film and its manufacturing method, magnetic recording medium using the same, and its manufacturing method - Google Patents

Abstract

PURPOSE:To make it possible to obtain a high-density magnetic recording medium by spreading fine inorganic particles on each of whose surfaces a monomolecular film comprising molecules of an organic compound is formed on a gas- water interface, transferring the formed film to a substrate and treating it chemically or physically. CONSTITUTION:A monomolecular film comprising molecules (A) of an organic compound is formed on te surfaces of fine inorganic particles (B) on each of which an oxide film of the constituent element is optionally formed, and the particles are spread on a gas-water interface. The formed film is transferred on a substrate to be treated chemically or physically for chemically combining components A with each other to obtain the title ultrathin film comprising component B fixed in a thin film and a thin organic film of component A formed on the surface of component B, wherein one terminal group of component A and component B are bonded together to form a siloxane bond of formula I or a bond of formula II and component A is chemically combined with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ultra-thin film made of inorganic fine particles and a method for manufacturing the same, and as an application thereof, a magnetic recording medium having a recording layer made of the ultra-thin film made of the inorganic fine particles and its manufacture. It is about the method.

Conventional technology Conventionally, inorganic fine particle ultra-thin films have been used as wiring materials, processing materials,
It is widely used as recording material, printing material, etc. A magnetic recording medium and a method for manufacturing the same will be described below as an example of a conventional technique.

The conventional manufacturing method for magnetic recording media is to create a magnetic paint by dispersing magnetic inorganic fine particles in a synthetic resin called a binder, and then to form a recording layer by coating this magnetic paint thinly and uniformly on a substrate. Many methods are used. Furthermore, in order to increase the coercive force, there is a step of applying a magnetic field to align the orientation of the magnetic inorganic particles after applying magnetic paint onto the substrate and before it dries.

Problems to be Solved by the Invention However, conventional methods for manufacturing magnetic recording media contain a large amount of binder made of non-magnetic synthetic resin, which is not suitable for achieving high density.

Furthermore, due to the viscosity of the binder, it is not easy to align the magnetic inorganic particles perfectly.

Furthermore, the surface of a magnetic recording medium needs to be flat and smooth, but it has been difficult to obtain a flat and smooth surface using conventional manufacturing methods.

Means for Solving the Problems The ultra-thin film of inorganic fine particles of the present invention consists of inorganic fine particles fixed in the form of a thin film, and an organic thin film made of organic compound molecules formed on the surface of the inorganic fine particles, and It is characterized by chemical bonds between molecules.

In order to produce an ultra-thin film of inorganic fine particles having the above structure, the method for producing an ultra-thin film of inorganic fine particles of the present invention includes the steps of uniformly forming a monomolecular film of organic compound molecules on the surface of the inorganic fine particles, and It is characterized by comprising a step of developing it on a water interface and transferring it to a substrate, and a step of subjecting the inorganic fine particles transferred to the substrate to chemical treatment or physical treatment for chemically bonding the organic compound molecules to each other. That is.

Further, in the magnetic recording medium of the present invention, the ultra-thin film of the inorganic fine particles of the present invention is formed using magnetic inorganic fine particles as the inorganic fine particles, and the ultra-thin film serves as a recording layer.

Effect: The ultra-thin film of inorganic fine particles and the method for producing the same according to the present invention have the above-described configuration, and can form an ultra-thin film of fine inorganic particles using a newer and easier method for handling inorganic fine particles. Furthermore, since the magnetic recording medium of the present invention and its manufacturing method do not contain any binder, it is possible to achieve high density, and it is also easy to align the orientation of the magnetic inorganic particles.

EXAMPLE Hereinafter, one example of the ultra-thin inorganic particle film of the present invention will be described in detail with reference to FIGS. 1 and 2.

Here, FIG. 1 is a schematic cross-sectional view of an ultra-thin film of inorganic fine particles, and FIG. 2 is an enlarged view of the part surrounded by circle A in FIG. 1.

1 is an inorganic fine particle with a diameter of 10 OA. An oxide film of a constituent element of the inorganic substance is formed around the inorganic fine particles 1, and organic compound molecules 2 having a linear hydrocarbon group are adsorbed onto the oxide film. The organic compound molecules 2 having linear hydrocarbon groups are chemically bonded to adjacent organic compound molecules having linear hydrocarbon groups.

3 refers to a chemical bond consisting of an ethylene bond. 4 is a substrate. As shown in FIG. 2, organic compound molecules 2 containing linear hydrocarbon groups form siloxane bonds 5 that form inorganic fine particles 1. Therefore, inorganic fine particles 1 are organic compound molecules 2 containing linear hydrocarbon groups.
Further, the organic compound molecule 2 having a linear hydrocarbon group is fixed by a chemical bond 3 consisting of an ethylene bond. Therefore, the retention of the inorganic fine particles 1 is excellent. Furthermore, since the Langmuir-Prodgett method can be used, an ultra-thin film of inorganic fine particles can be formed in a layered manner, and the thickness can be made uniform.

In this example, the inorganic fine particle ultra-thin film has only one layer, but it may be formed into a cumulative layer if necessary.

In addition, in this example, an example was shown in which the bond between organic compound molecules having a linear hydrocarbon group is an ethylene bond,
Needless to say, this is not the only option.

Furthermore, although this example shows an example in which the bond between the inorganic fine particles and the organic compound molecule having a linear hydrocarbon group is a siloxane bond, other bonds such as -8-inorganic bond may be used. I don't mind.

Hereinafter, the first embodiment of the method for producing an ultra-thin inorganic particle film of the present invention will be described in detail step by step with reference to FIG. Note that all of FIG. 3 are sectional views.

As the organic compound molecule to be adsorbed to the inorganic fine particles, for example, an organic compound molecule 10 containing a linear hydrocarbon group containing a lorsilane group and an acetylene bond, such as CH3-CEC-(CH2)+v-8i Cls, is mainly composed of chloroform. The inorganic fine particles 11 are dissolved in a non-aqueous solvent and stirred. The chlorosilane group reacts with the oxide film of the constituent element of the inorganic substance formed around the inorganic fine particles 11 to form a siloxane bond, and the organic compound 10 having a linear hydrocarbon group is adsorbed. The inorganic particles 11 subjected to the adsorption treatment are spread on the air-water interface 12, the inorganic particles 11 are collected by the barrier 13, and an appropriate pressure is applied to form an ultra-thin inorganic particle film 14. The inorganic fine particle ultra-thin film 14 is transferred to an arbitrary substrate 15, for example, a silicon substrate. Here, the organic compound molecules 10 that grow linear hydrocarbon groups adsorbed around the inorganic fine particles 11 are of course formed all over the periphery of the inorganic fine particles 11, but they are not depicted three-dimensionally to avoid complication in the drawing. (Figure 3 (A)).

Next, the ultra-thin inorganic particle film 14 formed on the substrate 15 is irradiated with an energy beam 16, for example, an electron beam, in an inert gas atmosphere (FIG. 3(B)).

An organic compound molecule in which an acetylene bond of an organic compound molecule 10 having a linear hydrocarbon group adsorbed around an inorganic fine particle 11 grows an adjacent linear hydrocarbon group by irradiation with an energy beam 16 such as an electron beam. A chemical reaction occurs with the acetylene bond 10 to form an ethylene bond 17. Here, the ethylene bond 17 is the same as the inorganic fine particle 1.
1 or between the acetylene bonds of organic compound molecules 10 having linear hydrocarbon groups adsorbed around adjacent inorganic fine particles 11, or between the acetylene bonds of organic compound molecules 10 having linear hydrocarbon groups adsorbed around adjacent inorganic fine particles 11. Although it is formed by a reaction between the two, it is shown schematically because it is complicated in the drawing (Fig. 3(C)).

Although only one layer of the ultra-thin inorganic particle film was formed in this example, a cumulative film can also be formed using the same method.

Furthermore, in this example, an acetylene bond was used as an unsaturated bond group in an organic compound molecule having a linear hydrocarbon group, but other unsaturated bond groups such as an ethylene bond or a diacetylene bond may also be used. Furthermore, in this example, an organic compound molecule having a linear hydrocarbon group whose terminal group is a chlorosilane group is used, but it is also possible to use, for example, a triazinedithiol derivative. When using triazinedithiol derivatives, there is no need to use nonaqueous solvents, and siloxane bonds are not formed.

Furthermore, in this example, the energy beam was irradiated after the inorganic fine particles were transferred to the substrate, but the energy beam may be irradiated on the air-water interface and then transferred.

Furthermore, in order to improve the orientation of the inorganic fine particles, a magnetic field or an electric field may be applied when the inorganic fine particles are sensitive to a magnetic field, when forming an ultra-thin film on the air-water interface, or when irradiating with an energy beam.

Hereinafter, a second embodiment of the method for producing an ultra-thin inorganic particle film of the present invention will be described in detail step by step with reference to FIG. Note that all of FIG. 3 are sectional views.

Here, the step of adsorbing organic compound molecules having linear hydrocarbon groups around the inorganic fine particles, and the step of forming an ultra-thin film of the inorganic fine particles on the air-water interface and transferring it to the substrate are the first steps. Since this is the same as the example, the description will be omitted.

Next, a catalyst made of a group 5 or 6 transition metal or a compound of the metal, such as tantalum chloride, is appropriately dissolved in a non-aqueous solvent, and the ultra-thin film of inorganic fine particles formed on the substrate is immersed therein. By immersion, the acetylene bonds in the organic compound molecules having linear hydrocarbon groups undergo a chemical reaction with the acetylene bonds in the adjacent organic compound molecules having linear hydrocarbon groups, forming ethylene bonds (Figure 3). (C)).

In this example, a catalyst made of a group 5 or 6 transition metal or a compound of the metal is used, but any catalyst may be used as long as it is capable of chemically bonding organic compound molecules.

Furthermore, in order to improve the orientation of the inorganic fine particles, a magnetic field or an electric field may be applied when the inorganic fine particles are sensitive to a magnetic field, when forming an ultra-thin film on the air-water interface, or when immersing them in a catalyst solution.

An embodiment of the magnetic recording medium of the present invention will be described below with reference to FIGS. 4 and 5. 4 is a schematic cross-sectional view of the magnetic recording medium, and FIG. 5 is an enlarged view of the portion surrounded by circle B in FIG. 4.

20 is a magnetic inorganic fine particle having a diameter of about 10 OA. An oxide film of a constituent element of the magnetic inorganic substance is formed around the magnetic inorganic fine particles 20, and organic compound molecules 21 having a linear hydrocarbon group are adsorbed onto the oxide film. Organic compound molecule 21 having the linear hydrocarbon group
are chemically bonded to adjacent organic compound molecules having linear hydrocarbon groups. Reference numeral 22 indicates a chemical bond formed by an ethylene bond between the organic compound molecules 21 having the linear hydrocarbon group. Further, 23 is a fluorine-substituted moiety provided at the end of the organic compound molecule 21 having the linear hydrocarbon group. 24 is a substrate. As shown in FIG. 5, organic compound molecules 21 having linear hydrocarbon groups form siloxane bonds 25 that become magnetic inorganic fine particles 20. As shown in FIG. Therefore, the magnetic inorganic fine particles 20 are fixed with organic compound molecules 21 having a linear hydrocarbon group, and the organic compound molecules 21 having a linear hydrocarbon group are fixed with a chemical bond 22 consisting of an ethylene bond. has been done. Therefore, the retention of magnetic inorganic fine particles is excellent. Furthermore, since the Langmuir-Prodgett method can be used, an ultra-thin film of magnetic inorganic particles can be formed in a layered manner, and the thickness can be made uniform.

Furthermore, organic compound molecule 21 having a linear hydrocarbon group
By replacing the hydrogen atoms at the terminal ends with fluorine atoms, the surface of the ultra-thin film of magnetic inorganic fine particles is always covered with fluorine atoms, resulting in excellent wear resistance against friction in magnetic heads, etc.

Furthermore, since an ultra-thin film of magnetic inorganic fine particles can be formed in a layered manner, it is easy to obtain the required magnetic properties.

Further, in this example, an example in which the bond between organic compound molecules having a linear hydrocarbon group is an ethylene bond is shown, but it goes without saying that the bond is not limited to this.

Hereinafter, one embodiment of the method for manufacturing a magnetic recording medium of the present invention will be explained step by step in detail with reference to FIG.

In addition, all FIG. 6 is a sectional view.

As an organic compound molecule adsorbed to magnetic inorganic fine particles,
For example, an organic compound molecule 30 having a linear hydrocarbon group containing a lorsilane group, a trifluoromethyl group, and an acetylene bond, such as CFz-CEC-(CHa)+t-8)CIa, is dissolved in a solvent mainly composed of chloroform. The magnetic inorganic fine particles 31 are placed therein and stirred. The chlorosilane group reacts with the oxide film of the constituent element of the magnetic inorganic material formed around the magnetic inorganic fine particles 31 to form a siloxane bond, and the organic compound molecule 30 having a linear hydrocarbon group is adsorbed. Magnetic inorganic fine particles 31 subjected to adsorption treatment are spread on an air-water interface 32, magnetic inorganic fine particles 31 are collected by a barrier 33, and an appropriate pressure is further applied to form an ultra-thin film of magnetic inorganic fine particles 34. At this time, a magnetic field 35 is further applied to improve the orientation of the magnetic inorganic fine particles 31. The magnetic inorganic fine particle ultra-thin film 34 is transferred to an arbitrary substrate 36, for example, a silicon substrate.

Here, the organic compound molecules 30 having a linear hydrocarbon group formed around the magnetic inorganic fine particles 31 are of course formed over the entire circumference of the magnetic inorganic fine particles 31, but they are depicted three-dimensionally to avoid complication in the drawing. No (Figure 6(A)).

Next, the ultra-thin magnetic inorganic particle film 34 formed on the substrate 36 is irradiated with an energy beam 37, for example, an electron beam (FIG. 8(B)).

An organic compound having a linear hydrocarbon group adjacent to an acetylene bond of an organic compound molecule 30 having a linear hydrocarbon group adsorbed around the magnetic inorganic fine particles 31 by irradiation with an energy beam 37 such as an electron beam. A chemical reaction occurs with the acetylene bond of molecule 30 to form ethylene bond 38. Here, the ethylene bond 38 is between the acetylene bonds of the organic compound molecule 30 having a linear hydrocarbon group adsorbed around the same magnetic inorganic fine particle 31, or the linear chain adsorbed around the adjacent magnetic inorganic fine particle 31. Although it is formed by a reaction between the acetylene bonds of the organic compound molecule 30 having a hydrocarbon group, it is shown schematically because the drawing is too complicated (FIG. 6(C)).

Next, a substrate 3 on which an ultra-thin magnetic inorganic particle film 34 is deposited by the same method as shown in FIGS. 6(A) and 6(B).
The magnetic recording medium of this example is created by further depositing an ultra-thin magnetic inorganic particle film 34 on the magnetic inorganic particle 6 to form a cumulative film (
Figure 8(D)).

Although this example shows an example of ethylene bond formation using an energy beam, a method using a catalyst made of a metal or a compound of the metal may also be used, as shown in the example of the method for producing an ultra-thin film of inorganic fine particles.

Further, in this example, the energy beam was irradiated after transferring the magnetic inorganic fine particles to the substrate, but the energy beam may be irradiated on the air-water interface and then transferred.

Further, in this example, an acetylene bond was used as an unsaturated bond group in an organic compound having a linear hydrocarbon group, but other unsaturated bond groups such as an ethylene bond or a diacetylene bond may be used.

Furthermore, in this example, a magnetic field for enhancing orientation was applied when forming an ultra-thin film of magnetic inorganic fine particles on the air-water interface, but it may also be applied when irradiating an energy beam.

Furthermore, although a magnetic field is used in this embodiment, an electric field may also be used.

Effects of the Invention The ultra-thin film of inorganic fine particles and the method for producing the same of the present invention provide a new method for handling inorganic fine particles. Further, as an application thereof, a magnetic recording medium having a recording layer made of an ultra-thin film made of inorganic fine particles and a method for manufacturing the same can achieve high density since there is no binder, which is a problem with conventional magnetic recording media. moreover,
It has excellent retention of inorganic particles and does not require the addition of conventional lubricants. Furthermore, since the inorganic fine particles are covered with a water-repellent monolayer, they have very high weather resistance. Furthermore, when the present invention is applied to a perpendicular magnetic recording medium, a high-performance magnetic recording medium can be obtained, and its manufacture becomes extremely easy. In addition, applications other than magnetic recording media using the inorganic fine particle ultra-thin film of the present invention and its manufacturing method include applications such as wiring materials, processing materials such as grindstones, photosensitive recording materials, and printing materials.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of one embodiment of the inorganic fine particle ultra-thin film of the present invention, FIG. 2 is an enlarged view of the part surrounded by circle A in FIG. 1, and FIG. 3 is the production of the inorganic fine particle ultra-thin film of the present invention. FIG. 4 is a schematic cross-sectional view explaining an example of the magnetic recording medium of the present invention step by step. FIG. 5 is a schematic cross-sectional view explaining an example of the magnetic recording medium of the present invention. FIG. The enlarged view and FIG. 8 are schematic sectional views illustrating step-by-step an embodiment of the method for manufacturing a magnetic recording medium of the present invention. 1.11...Inorganic fine particles, 2,10,21.30
...Organic compound molecule having a linear hydrocarbon group, 3
．． 22...Chemical bond, 5.25...Siloxane bond, 18.37...Energy beam, 17°38...Ethylene bond, 20.31...Magnetic inorganic fine particles, 23...Fluorine substitution part, 35...
magnetic field. Name of agent: Patent attorney Shigetaka Awano and one other person (C) #, machine ￥S Suzume Mata Jinko 17 Ethylene Heat) (A) Position (A) (B) Diagram <C)

Claims (15)

[Claims] (1) It is characterized by comprising inorganic fine particles fixed in the form of a thin film and an organic thin film made of organic compound molecules formed on the surface of the inorganic fine particles, and the organic compound molecules are chemically bonded to each other. Ultra-thin film of inorganic particles. (2) The ultra-thin film of inorganic fine particles according to claim 1, wherein an oxide film of a constituent element of the inorganic substance is formed on the surface of the inorganic fine particles. (3) Claim 1 characterized in that the chemical bond between one end group of the organic compound molecule and the inorganic fine particle is a ▲numerical formula, chemical formula, table, etc.▼ bond (siloxane bond) or -S-inorganic bond. or the inorganic fine particle ultra-thin film described in 2. (4) A step of uniformly forming a monomolecular film made of organic compound molecules on the surface of the inorganic fine particles, a step of developing the inorganic fine particles on the air-water interface and transferring them to the substrate, and a step of transferring the inorganic fine particles to the substrate. A method for producing an ultra-thin film of inorganic fine particles, comprising the step of: performing a chemical treatment or a physical treatment for chemically bonding the organic compound molecules to each other. (5) The method for producing an ultra-thin film of inorganic fine particles according to claim 4, wherein the step of forming a monomolecular film made of organic compound molecules on the surface of the inorganic fine particles is a step using a chemisorption method. (6) An organic compound molecule has a linear hydrocarbon group having 10 or more CH_2 groups and has a group that performs a polymerization reaction therein, and one end of the organic compound molecule has an adsorption reaction with the surface of an inorganic fine particle. The method for producing an ultra-thin film of inorganic fine particles according to claim 4 or 5, wherein the inorganic fine particle ultra-thin film has a group that performs the following. (7) The method for producing an ultra-thin film of inorganic fine particles according to claim 6, wherein the group that performs an adsorption reaction with the surface of the inorganic fine particles is a (mono-, di-, or tri)chlorosilane group or a triazinedithiol group. (8) The method for producing an ultra-thin film of inorganic fine particles according to claim 6 or 7, wherein the group that performs the polymerization reaction is an unsaturated bonding group. (9) The method for producing an ultra-thin inorganic particle film according to any one of claims 4 to 8, wherein the step of transferring the inorganic particles onto the substrate is a step using the Langmuir-Prodgett method. (10) Claims 4 to 9, characterized in that the step of performing physical treatment to chemically bond organic compound molecules is a step of irradiating energy beams such as ultraviolet rays, deep ultraviolet rays, electron beams, and X-rays. A method for producing an ultra-thin film of inorganic fine particles according to any one of the above. (11) The method for producing an ultra-thin film of inorganic fine particles according to any one of claims 4 to 9, characterized in that the step of performing a chemical treatment for chemically bonding organic compound molecules is a step of performing a catalytic reaction. . (12) It includes magnetic inorganic fine particles fixed in the form of a thin film, and an organic thin film made of organic compound molecules formed on the surface of the magnetic inorganic fine particles, and the organic compound molecules are chemically bonded to each other. magnetic recording media. (13) The organic compound molecule has a linear hydrocarbon group having a group that performs a polymerization reaction therein, and the chemical bond between one end group of the organic compound molecule and the magnetic inorganic fine particles is expressed by ▲ mathematical formula, chemical formula , tables, etc. ▼ It is a bond (siloxane bond) or -S- inorganic bond, and one or more hydrogen atoms of the methyl group at the other end are replaced with fluorine atoms, and there is a bond between the groups that performs the polymerization reaction. 13. The magnetic recording medium according to claim 12, wherein the magnetic recording medium is chemically bonded through a polymerization reaction. (14) A step of uniformly forming a monomolecular film made of organic compound molecules on the surface of the magnetic inorganic fine particles, a step of developing the magnetic inorganic fine particles on the air-water interface and transferring them to the substrate, and a step of developing the magnetic inorganic fine particles on the air-water interface and transferring them to the substrate. A method for manufacturing a magnetic recording medium, comprising the step of subjecting magnetic inorganic fine particles to chemical treatment or physical treatment for chemically bonding the organic compound molecules to each other. (15) In the process of spreading magnetic inorganic fine particles covered with a monomolecular film made of organic compound molecules on an air-water interface and transferring them to a substrate, a magnetic field is applied when the particles are spread on the air-water interface. The method for manufacturing a magnetic recording medium according to claim 14.