JPH06101031A - Production device for magnetic recording medium and production of the same - Google Patents

Abstract

PURPOSE:To obtain the magnetic recording medium which is excellent in magnetic property and capable of high density recording by forming the vessel of a magnetic material with the base stock consisting essentially of boron carbide. CONSTITUTION:The crucible 5 in which the magnetic material is housed is provided previously with a carbon fiber between the inside mold and the outside mold both of which are firmed with boron carbide (B4C) in the prescribed shape and is exerted with force from above and below and heated and fired. A magnetic alloy 6 placed in the crucible 5 is evaporated and the magnetic alloy 6 is obliquely vapor deposited on a substrate 11 and the magnetic recording medium is produced. Even if the boron carbide constituting the crucible 5 is mixed in a magnetic film, the variation in the magnetic property is not observed.

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 manufacturing apparatus and method.

[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. In particular, means for forming a magnetic film by vapor deposition means is said to be preferable because the film formation rate is faster than that by sputtering.

By the way, a magnetic recording medium manufacturing apparatus using such a vapor deposition means is generally constructed as shown in FIG. In FIG. 3, 21 is a cooling can and 2 is a cooling can.
2 is a polyethylene terephthalate (PET) film supply side roll, 23 is a PET film winding side roll,
Reference numeral 24 is a shield plate, 25 is a crucible, 26 is a magnetic alloy, 27 is an electron gun, and 28 is a vacuum container. That is, the vacuum container 2
After evacuating the inside of the crucible 8 to a predetermined vacuum degree, the electron gun 27 is operated to evaporate the magnetic alloy 26 in the crucible 25, and P
A magnetic recording medium is manufactured by depositing a magnetic alloy 26 on an ET film.

In such a magnetic recording medium manufacturing apparatus, the crucible 25 is made of, for example, MgO, ZrO, BeO, A.
l ₂ O ₃ , Si ₃ N ₄ , BN, ThO ₂ , CaO, Si
It is composed of ceramics such as O ₂ . However, the magnetic characteristics of the magnetic recording medium obtained in this way were sometimes questionable. That is, there was a suspicion that the magnetic properties were worse than the estimated values.

[0006]

DISCLOSURE OF THE INVENTION As a result of earnestly researching the above problems, it has been found that the crucible itself containing the vapor deposition source material may have a problem. That is, I noticed that the magnetic characteristics were slightly different depending on the various crucibles.

The present invention has been made based on such knowledge, and an object of the present invention is to provide a technique capable of manufacturing a magnetic recording medium having excellent magnetic characteristics and capable of high density recording. An object of the present invention is an apparatus for producing a magnetic recording medium that forms a magnetic film by evaporating a magnetic material contained in a container and depositing the magnetic material on a substrate, wherein the container is composed mainly of boron carbide. And a magnetic recording medium manufacturing apparatus.

A method of manufacturing a magnetic recording medium in which a magnetic film is formed by evaporating a magnetic material placed in a container and depositing it on a substrate, wherein the container is made of a material containing boron carbide as a main component. This is achieved by a method for manufacturing a magnetic recording medium, characterized by using the container thus obtained. It is more preferable that the container according to the present invention is configured by interposing a carbon fiber in boron carbide with a cloth woven such as a plain woven cloth or a woven cloth.

The present invention will be described in more detail below. FIG. 1 shows a magnetic recording medium manufacturing apparatus (vapor deposition apparatus), in which 1 is a cooling can and 2 is a substrate 11 such as a PET film.
Supply side roll, 3 winding side roll of PET film 11, 4 shielding plate, 5 crucible made of boron carbide (B ₄ C), 6 magnetic metal such as Fe, 7 electron gun, 8 vacuum It is a container.

In the crucible 5, carbon-based fibers are arranged between an inner mold and an outer mold which are previously molded into a predetermined shape with B ₄ C, and a force is applied from above and below, and heating and firing are performed. It is configured by As a result, the crucible 5 is significantly strengthened, and even if heating and cooling are repeated,
Hard to be damaged by thermal strain. By the way, in the apparatus configured as described above, after evacuating the inside of the vacuum container 8 to a predetermined vacuum degree, the electron gun 7 is operated to evaporate the magnetic alloy 6 in the crucible 5 to remove a PET film or the like. Board 11
A magnetic recording medium is manufactured by obliquely vapor-depositing the magnetic metal 6.

The magnetic characteristics S. F. D. (Suiching Field
Distribution, ΔH / Hc, ΔH is BH
When the half-value width of the loop differential curve, Hc is the coercive force) was examined, it was found that the characteristics of the magnetic film made of the iron-based magnetic material varied depending on the material of the crucible 5. In addition, this S.
F. D. The larger the value of, the greater the noise.

That is, the crucible 5 is made of, for example, MgO, Al.
_When composed of ₂ O ₃ , ThO _2, etc., these materials may be mixed in the magnetic film in some cases. F. D. Showed an increasing trend. However, even if the boron carbide constituting the crucible of the present invention is mixed, the S. F. D. Did not show an increasing trend.

When the crucible 5 is made of CaO,
Since CaO has a high water absorption, it has a poor durability against heating and cooling, which causes a problem, and BeO also has a problem of toxicity. However, these problems do not exist in the case of boron carbide. FIG. 2 shows a schematic sectional view of the magnetic recording medium obtained by the present invention. In the figure, 11 is a non-magnetic substrate, and this substrate 11 is polyester such as PET, polyamide, polyimide, polysulfone, polycarbonate,
An olefin resin such as polypropylene, a cellulose resin, a polymer material such as a vinyl chloride resin, an inorganic material such as glass and ceramics, and a metal material such as an aluminum alloy are used.

An undercoat layer 12 for improving the adhesion of the magnetic layer is provided on the surface of the substrate 11. That is, to improve the adhesion of the magnetic layer formed by the oblique vapor deposition method by appropriately roughening the surface roughness, and further to improve the runnability by making the surface roughness of the magnetic recording medium surface moderate. For example, the undercoat layer 12 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 13 is provided on the undercoat layer 12 by the vapor deposition apparatus described above. For example, the ferromagnetic metal material is evaporated by resistance heating, high frequency heating, electron beam heating or the like in a vacuum atmosphere of about 10 ⁻⁴ to 10 ⁻⁶ Torr, and the undercoat layer 12 of the substrate 11 is evaporated.
By depositing (evaporating) on the surface, the magnetic layer 13 is formed to a thickness of 0.04 to 1 μm. In order to obtain a higher coercive force, it is preferable to use the oblique vapor deposition method in which the ferromagnetic metal material is obliquely vapor-deposited on the substrate.

As a material for forming the magnetic layer 13, for example, in addition to metals such as Fe, Co and Ni, a Co--Ni alloy,
Co-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 13, oxygen is supplied to the vapor deposition portion and is forcedly oxidized to oxidize the surface layer portion of the magnetic layer 13 to form a protective layer 14 made of an oxide film. The thickness of the protective layer 14 composed of this oxide film is about several tens of liters, and an oxide film of this thickness may be composed of natural oxidation. It may not be necessary to take the measures of.

Reference numeral 15 is a lubricant layer provided on the protective layer 14 made of an oxide film. That is, the lubricant layer 15 is
By applying a coating material containing a lubricant by a predetermined means, a thickness of about 5 to 50Å, preferably about 10 to 30Å is provided. Reference numeral 16 is a back coat layer provided on the other surface of the substrate 11 and containing carbon black or the like.

A specific example will be described below.

[0020]

【Example】

Example 1 A PET film 11 having a thickness of 9.3 μm was mounted on the vacuum vapor deposition apparatus as shown in FIG. The crucible 5 used was made of B ₄ C and had a thickness of 4 mm and an internal volume of 1
00 cc.

First, after evacuating the inside of the vacuum container 8 to a predetermined vacuum degree, the electron gun 7 is operated to operate the crucible 5
The magnetic metal (Fe) 6 in the inside is evaporated, and the Fe magnetic metal 6 is 1500
Å Thick vapor deposition. Then, oxygen was supplied from the oxygen gas introducing pipe 9 to forcibly oxidize the surface layer of the vapor deposition film, thereby forming 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 back coat coating composition in which a binder resin composed of a vinyl chloride resin and a urethane prepolymer are dispersed are applied to the PET film 11 on the side opposite to the magnetic layer by a direct gravure method, and the dry thickness is applied. Was provided with a back coat layer having a thickness of 0.5 μm. After this,
Fluorine perfluoropolyether (grade: FOMB
LIN ZDIAC Carboxyl group modified, manufactured by Nippon Montedison Co., Ltd. is a fluorine-inert liquid (Fluorinert, FC
-84, manufactured by Sumitomo 3M Co., Ltd.) and applied with a paint prepared by diluting and dispersing so as to have a concentration of 0.1% by a die coating method so as to have a thickness after drying of about 20Å and dried at 70 ° C. It was

After that, a magnetic tape as shown in FIG. 2 was produced by slitting it into a predetermined width. [Comparative Example 1] A crucible 5 made of MgO was used in the same manner. [Comparative Example 2] A crucible 5 made of Al ₂ O ₃ was used in the same manner.

[Characteristics] With respect to the magnetic tapes obtained in the above examples, S. F. D. The output and the noise level at 4 MHz and 4 MHz were examined. The results are shown in Table 1 below. Table 1 S. F. D. Output (dBm) Noise (dBm) Example 1 0.95 -10.4 -62.8 Comparative example 1 1.26 -10.7 -61.1 Comparative example 2 1.33 -10.9 -61.4

[0025]

According to the present invention, it is possible to efficiently provide a high-performance magnetic recording medium at low cost.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of an embodiment of an apparatus for manufacturing a magnetic recording medium according to the present invention.

FIG. 2 is a schematic sectional view of a magnetic recording medium according to the present invention.

FIG. 3 is a schematic explanatory diagram of a conventional magnetic recording medium manufacturing apparatus.

[Explanation of symbols] 1 cooling can 2 supply side roll 3 winding side roll 4 shield plate 5 crucible 6 magnetic metal 7 electron gun 8 vacuum container

Claims (2)

[Claims] 1. Evaporating the magnetic material contained in a container,
An apparatus for manufacturing a magnetic recording medium having a magnetic film formed by depositing it on a substrate, wherein the container is made of a material containing boron carbide as a main component. 2. Evaporating the magnetic material contained in the container,
A method of manufacturing a magnetic recording medium in which a magnetic film is formed by depositing on a substrate, wherein a container made of a material containing boron carbide as a main component is used as the container. Method.