JPH06111289A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To record at a high density and to improve durability by forming a lubricant layer of fluorine series titanate compound in a magnetic recording medium having a magnetic layer and the lubricant layer formed on a nonmagnetic board. CONSTITUTION:A magnetic recording medium is formed by sequentially laminating an undercoating layer 2, a magnetic layer 3, a protective layer 4 and a lubricant layer 5 on a nonmagnetic board 1. A back coating layer 6 is provided on the other surface of the board 1. The layer 5 is formed by coating with solution in which fluorine series titanate compound is dissolved in alcohol series solvent such as ethanol, by a gravure system and drying it. Thus, the medium which has excellent and can be recorded in high density can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium.

[0002]

BACKGROUND OF THE INVENTION In a magnetic recording medium such as a magnetic tape, due to a demand for high density recording, a binder resin is not used as a magnetic layer provided on a non-magnetic support, instead of a coating type using a binder resin. It is well known that a metal thin film type that is not used has been proposed.

That is, there has been proposed a magnetic recording medium having a magnetic layer formed by a wet plating means such as electroless plating, or a dry plating means such as vacuum deposition, sputtering or ion plating. Since the magnetic recording medium of this type has a high packing density of magnetic material, it is suitable for high-density recording. However, unlike a coating type magnetic recording medium, it is not possible to add a lubricant to the magnetic layer. Therefore, the sliding contact between the magnetic recording medium and the magnetic head is likely to adversely affect the magnetic layer, and The characteristics also deteriorate.

From such a viewpoint, it has been proposed to provide a lubricant layer on the magnetic layer. For example, Japanese Patent Application Laid-Open No. 3-171417 proposes that the lubricant layer provided on the magnetic layer is composed of a mixture containing a partially fluorinated alkyl lubricant and perfluoroalkyl polyether, and JP-A-3-286424 proposes that the lubricant layer provided on the magnetic layer is composed of a long-chain alkylsilane compound.

However, these proposals are not sufficient, and further proposals are awaited.

[0006]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a magnetic recording medium having high durability and high density recording. An object of the present invention is a magnetic recording medium including a non-magnetic substrate, a magnetic layer, and a lubricant layer, wherein the lubricant layer is composed of a fluorine-based titanate compound. Is achieved by a magnetic recording medium.

A magnetic recording medium comprising a non-magnetic substrate, a magnetic layer, an oxide-based protective layer, and a lubricant layer, wherein the lubricant layer is composed of a fluorine-based titanate compound. And a magnetic recording medium. The fluoro titanate compound used in the present invention is

[0008]

[Chemical 2]

It is preferable that R (F) is a group in which H of a hydrocarbon is replaced by F, and X ₁ , X ₂ and X ₃ are hydrolyzable groups bonded to a Ti atom. , Especially R
(F) is, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, octyl group,
A fluoroalkyl group in which at least one H of an alkyl group such as a decyl group is substituted with F (more preferably, all H are substituted with F), a vinyl group, a propenyl group, a methylvinyl group Fluorine titanate having a group such as a fluoroalkenyl group in which at least one H of an alkenyl group such as a butenyl group and a hexenyl group is substituted with F (more preferably, one in which all H are substituted with F). Compounds are more preferred.

The present invention will be described in more detail below. FIG. 1 shows a schematic sectional view of a magnetic recording medium according to the present invention. In the figure, 1 is a non-magnetic substrate, and this substrate 1 is made of polyester such as polyethylene terephthalate, polyamide, polyimide, polysulfone, polycarbonate, olefin resin such as polypropylene, cellulose resin, vinyl chloride resin. Polymeric materials such as resins,
Inorganic materials such as glass and ceramics, and metal materials such as aluminum alloys are used.

An undercoat layer 2 for improving the adhesion of the magnetic layer is provided on the surface of the substrate 1. That is, in order to improve the adhesion of the magnetic layer formed by dry plating by appropriately roughening the surface roughness and further improve the runnability by making the surface roughness of the magnetic recording medium surface moderate, for example, The undercoat layer 2 is formed by providing a coating film containing particles such as SiO ₂ and having a thickness of 0.01 to 0.5 μm.

A metal thin film type magnetic layer 3 is provided on the undercoat layer 2 by a wet plating means such as electroless plating or a dry plating means such as vacuum deposition, sputtering or ion plating. For example, 10
By evaporating the ferromagnetic metal material by resistance heating, high frequency heating, electron beam heating or the like in a vacuum atmosphere of about ^-4 to 10 ^-6 Torr and depositing (evaporating) it on the undercoat layer 2 surface of the substrate 1, The magnetic layer 3 is formed with a thickness of 0.04 to 1 μm. When the vacuum vapor deposition method is adopted, it is preferable to use the oblique vapor deposition method in which the ferromagnetic metal material is obliquely vapor-deposited on the substrate in order to obtain higher coercive force.

Examples of the material forming the magnetic layer 3 include metals such as Fe, Co and Ni, as well as Co--Ni alloys and C.
o-Pt alloy, Co-Ni-Pt alloy, Fe-Co alloy, Fe-Ni alloy, Fe-Co-Ni alloy, Fe-C
Examples thereof include o-B alloys, Co-Ni-Fe-B alloys, Co-Cr alloys, and alloys containing metals such as Al and Ta.

At the time of forming the magnetic layer 3, oxygen is supplied to the vapor deposition portion and forced oxidation is performed to oxidize the surface layer portion of the magnetic layer 3 to form a protective layer 4 of an oxide film.
The protective layer 4 made of this oxide film has a thickness of several tens of liters.
The oxide film having such a thickness is sometimes formed by natural oxidation, and in such a case, it may not be necessary to take a forced oxidation means.

Reference numeral 5 is a lubricant layer provided on the protective layer 4 made of an oxide film. That is, the lubricant layer 5 is formed by applying a coating material containing a lubricant by a predetermined means,
The thickness is about 5 to 50Å, preferably about 10 to 30Å. As the solvent of the lubricant-containing paint, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone,
Ketone-based solvent such as cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, ester-based solvent such as glycol monomethyl ether acetate, ether, glycol dimethyl ether, glycol monoethyl ether, glycol ether-based solvent such as dioxane, Aromatic hydrocarbon solvents such as benzene, toluene and xylene, alcohol solvents such as methanol and ethanol,
A chlorinated hydrocarbon solvent such as methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin and dichlorobenzene can be appropriately used.

As the coating means, various methods such as a gravure method, a reverse method and an extrusion method can be used. As the lubricant provided on the surface, the fluorine-based titanate compound described in the above general formula is used. Specific examples of the fluorine-based titanate compound used in the present invention include the structures shown below. Of course, it is not limited to this.

[0017]

[Chemical 3]

[0018]

[Chemical 4]

[0019]

[Chemical 5]

[0020]

[Chemical 6]

[0021]

[Chemical 7]

[0022]

[Chemical 8]

[0023]

[Chemical 9]

[0024]

[Chemical 10]

[0025]

[Chemical 11]

Reference numeral 6 is a back coat layer provided on the other surface of the substrate 1 and containing carbon black or the like. Less than,
A specific example is given and demonstrated.

[0027]

【Example】

Example 1 A PET film 10 having a thickness of 9.3 μm was mounted on a vacuum vapor deposition apparatus as shown in FIG. Incidentally, FIG.
Among them, 11 is a cooling can, 12 is a supply side roll of the PET film 10, 13 is a winding side roll of the PET film 10, 14 is a shielding plate, 15 is a crucible, 16 is a magnetic metal (for example, Co-Ni (20 atoms). %) Alloy), 17 is an electron gun, 18 is a vacuum container, and 19 is an oxygen gas introduction tube.

First, after the inside of the vacuum container 18 is evacuated to a predetermined vacuum degree, the electron gun 17 is operated to evaporate the magnetic metal 16 and the magnetic metal 16 is applied to the PET film 10 by the oblique vapor deposition method. Was deposited to a thickness of 1500Å.
Then, oxygen was supplied from an oxygen gas introduction pipe to forcibly oxidize the surface layer of the vapor deposition film to form a surface protective layer of an oxide film having a thickness of several tens of liters.

After this, the tape was taken out and the average particle size was 20
nm carbon black and a backcoating paint in which a binder resin composed of a vinyl chloride resin and a urethane prepolymer are dispersed are applied to the PET film 10 on the side opposite to the magnetic layer by a direct gravure method to obtain a dry thickness. Was provided with a back coat layer having a thickness of 0.5 μm. After this,
One of the fluorine-based titanate coupling agents of the above [Chemical Formula 3]
A wt% methanol solution was applied by a die coating method so that the thickness after drying was about 20Å, and dried at 70 ° C.

After that, the magnetic tape as shown in FIG. 1 was produced by slitting it into a predetermined width. [Example 2] The procedure of Example 1 was repeated except that the fluorine-based titanate coupling agent of [Chemical formula 4] was used instead of the above [Chemical formula 3] to prepare a magnetic tape as shown in FIG. Comparative Example 1 In Example 1, C ₉ F ₁₇ O (CH ₂ ) ₂₀ COOH (partially fluorinated alkyl lubricant) and Krytox 157SL (manufactured by DuPont, perfluoroalkylpolyether) were used in place of [Chemical Formula 3]. The same procedure was performed using a 2: 1 mixture with the above) to prepare a magnetic tape as shown in FIG.

[Comparative Example 2] The same procedure as in Example 1 was carried out by using γ- (N, N-dioctadecylsuccinylpropylamino) triethoxysilane in place of the above [Chemical Formula 3]. Magnetic tape was manufactured. [Characteristics] The magnetic tape obtained in each of the above examples was mounted in a recording / reproducing apparatus, and still reproduction was carried out for 1 hour. The results are shown in Table 1.

Table 1 Example 1 4 MHz video output drops by only 0.6 dB. Example 2 4 MHz video output drops by only 0.6 dB. Comparative Example 1 The 4 MHz video output dropped by 1.4 dB. Comparative Example 2 The 4 MHz video output dropped by 3.9 dB.

[0033]

According to the present invention, a magnetic recording medium having high durability and high density recording can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a magnetic recording medium.

FIG. 2 is a schematic diagram of a magnetic recording medium manufacturing apparatus.

[Explanation of symbols]

 1 non-magnetic substrate 2 undercoat layer 3 magnetic layer 4 protective layer 5 lubricant layer

Claims (4)

[Claims] 1. A magnetic recording medium comprising a non-magnetic substrate, a magnetic layer, and a lubricant layer, wherein the lubricant layer is composed of a fluorine-based titanate compound. And a magnetic recording medium. 2. A magnetic recording medium comprising a non-magnetic substrate, a magnetic layer, an oxide-based protective layer, and a lubricant layer, wherein the lubricant layer is composed of a fluorine-based titanate compound. A magnetic recording medium characterized by the following. 3. A fluorine-based titanate compound is represented by: (However, R (F) is a group in which H of a hydrocarbon is substituted with F,
The magnetic recording medium according to claim 1 or ₂ , wherein X ₁ , X ₂ and X ₃ are hydrolyzable groups bonded to Ti atoms. 4. The magnetic recording medium according to claim 3, wherein R (F) is a fluoroalkyl group or a fluoroalkenyl group.