JPS60224125A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain the titled magnetic recording medium having excellent weather resistance by vapor-depositing a magnetic metallic material on the surface of a moving substrate while changing the incident angle continuously from a high to a low incident angle, and vapor-depositing a nonmagnetic metallic material on the vapor-deposited layer while changing the incident angle continuously from a low to a high incident angle to form a vapor-deposited film. CONSTITUTION:A vapor-depositing material 23 consisting of a metal such as Ni, Co, Fe, etc. or the alloy of said metals is evaporated from a crucible 25 and vapor-deposited on a substrate 21 (1 of another figure) to form an inclined columnar magnetic layer 2 while transporting the strip-shaped substrate 21 of a polyester film, etc. along a cooling can 22 in the direction as shown by the arrow A, and changing the incident angle of the vapor flow continuously from a high to a low incident angle with deposition preventive plates 27 and 28. Then a nonmagnetic metal 24 selected from Cr, Ti, Sn, Cu, and Al is evaporated from a crucible 26 and vapor-deposited to form a nonmagnetic metallic layer 3 while winding reversely the substrate 21 in the direction as shown by the arrow B and again transporting the substrate in the direction as shown by the arrow A, and changing the incident angle continuously from a low to a high incident angle with deposition preventive plates 28 and 29. After repeating said traveling, the recording medium having excellent weather resistance is obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magnetic recording medium in which a ferromagnetic metal thin film is provided as a magnetic recording layer on a non-magnetic support by oblique incidence evaporation. Regarding nine magnetic recording media with improved weather resistance.

[Prior art]

Conventionally, as a magnetic recording medium, r-
Fe203. Co-doped γFe2O3hFe30
4. Co-doped p e304 sγ-Fe203
and Fe3O4 are rutolide compounds, magnetic powders such as CrO2, or ferromagnetic alloy powders, etc. are mixed with powder magnetic materials in organic binders such as vinyl chloride-vinyl acetate copolymer, styrene-butadiene copolymer, epoxy resin, polyurethane resin, etc. Paint-on type products have been widely used, in which a dispersed material is applied and dried. In recent years, with the increasing demand for high-density recording, a magnetic recording layer is a ferromagnetic metal thin film formed by a paper deposition method such as vacuum evaporation, sputtering, or ion blating, or a plating method such as electroplating or electroless plating. BACKGROUND ART So-called binder-free magnetic recording media that do not use a binder have attracted attention, and various efforts are being made to put them into practical use.

Conventional coating-type magnetic recording media mainly use metal oxides, which have lower saturation magnetization than ferromagnetic metals, as magnetic materials, so the thinning required for high-density recording leads to a reduction in signal output, which has reached its limit. Moreover, the manufacturing process is complicated, and it has the drawback of requiring large auxiliary equipment for solvent recovery and pollution prevention. In a non-binder type magnetic recording medium, a ferromagnetic metal having a saturation magnetization υ larger than that of the above oxide is formed as a thin film without containing a non-magnetic substance such as a binder.

It has the advantage that it can be made ultra-thin for high-density recording, and the manufacturing process is further simplified.

As one of the conditions required for magnetic recording media for high-density recording, high coercive force and thinner layers have been proposed both theoretically and experimentally, and are an order of magnitude higher than magnetic recording media at coating temperatures. There are great expectations for non-binder type magnetic recording media that can be easily made into small and thin layers and have a high saturation magnetic flux density.

In particular, the method using vacuum evaporation has great advantages because it does not require drainage treatment as is the case with plating, the manufacturing process is simple, and the deposition rate of the film can be increased. A method of manufacturing a magnetic film having coercive force and squareness desirable for magnetic recording media by vacuum deposition is disclosed in U.S. Patent JJ44J4.
The oblique vapor deposition method described in No. J2, No. 334AJjJJ, etc. is known.

Furthermore, major problems concerning magnetic recording media made of ferromagnetic metal thin films include strength against corrosion and abrasion, and running stability. The magnetic recording medium is subjected to high-speed relative motion with the magnetic head during the recording, reproducing, and erasing processes of magnetic signals, but in this case, the running must be smooth and stable, and at the same time, the movement with the head must be stable. No wear or damage due to contact shall occur. It is also required that the recorded signals do not frequently decrease or disappear due to changes over time due to corrosion or the like during storage of the magnetic recording medium. Providing a protective layer is being considered as a method of improving durability and weather resistance.

As a method for improving the characteristics of metal thin film magnetic recording media by providing a protective layer, for example, a US patent has been published on providing an organic layer! , 4444.1j No. 6, ibid. a.

No. 49.360, same u, /j2,4 AI No. 7, same da.

/12. Lit No., μ, 333.21rj, West German Patent Publication λ, Takota, No. 1177, J, 02g, No. 71 are known, and it is also possible to provide a metal layer such as Rh. U.S. Patent J, J/A, No. 140, ≠, 2μ3.
It is known from No. 0071.

Furthermore, in order to improve durability and weather resistance, %Cr is vapor deposited on the surface of a ferromagnetic metal thin film in a moderate vacuum to form a mixture layer of %Cr and Cr oxide (Tokuko Akihirota ≠ 393). No. 1) or a method of providing a laminated protective layer of a Cr layer and Si and Si oxide layers (Japanese Patent Publication No. 11-3741)
j) is known. However, the rust resistance of conventional protective films was not sufficient, and further improvements were required for practical use. In particular, the weather resistance of the magnetic tape after being repeatedly run on a VTR or the like has been a major drawback.

[Purpose of the invention]

An object of the present invention is to provide a magnetic recording medium having a protective film that has excellent weather resistance, especially after repeated running on a deck such as a VTR.

[Structure of the invention]

The present invention provides a magnetic recording medium in which a vapor flow of a magnetic metal material evaporated from an evaporation source is deposited on a moving substrate, wherein the incident angle of the vapor flow of a magnetic metal material with respect to the moving substrate is set to a high incident angle. On the magnetic vapor deposited film, which has a curved inclined columnar structure, the incident angle is changed continuously from low to low.
The present invention relates to a magnetic recording medium characterized by being provided with a non-magnetic metal vapor deposited film formed by continuously changing the incident angle of a vapor flow of a non-magnetic metal material onto the moving base from a low incident angle to a high incident angle. Furthermore, CrsT is used as a non-magnetic metal material.
is Sns (-u% kl)

Furthermore, Cr%TtsSn is used as a non-magnetic metal material.

The magnetic recording medium described above uses at least one selected from Cu and AI.

In the present invention, the oblique incidence vapor deposition method is a method in which a vapor flow of a film-forming metal material is made incident at a certain incident angle θ relative to the normal to the substrate surface to deposit a vapor-deposited thin film on the substrate surface. In the present invention, when forming a magnetic thin film by oblique incidence deposition, oblique incidence deposition is started at an incident angle θmax, and the incident angle θ is changed so as to continuously decrease as the substrate moves. The deposition of the magnetic thin film is stopped at the incident angle θmin. On the thus formed magnetic thin film, a non-magnetic metal material is further formed by continuously increasing the incident angle θ starting from the incident angle θmin' and changing it up to the incident angle θmax'.
In particular, at least seven types of nonmagnetic metal materials selected from Crs T l b S nh Cu5Al are formed as a protective film. In the present invention, the incident angle θ is 2
! 0C to 00 is preferable.

In particular, θrn a X s θmax' is jO0~riO
o.

θrn 1 n h 0m i n ' is koj0~7!
0 is preferred.

FIG. 1 shows a magnetic recording medium according to the invention. A magnetic metal vapor deposited film 2 is provided on a support l, and a nonmagnetic metal vapor deposited film 3 is further formed thereon. In creating the magnetic metal vapor deposited film, the support L is conveyed in the direction of arrow A while the incident angle on the surface of the support is continuously changed from θmax to θmin. A membrane is obtained. The thickness of the magnetic metal vapor-deposited film is approximately 0.0 mm because it needs to be thick enough to provide sufficient output as a magnetic recording medium and thin enough to perform high-density recording.
, 02 g@ to j, On? 71. Preferably 0°0!
From ti@, this is OBg1. In forming the non-magnetic metal vapor deposited film 3, the incident angle of the vapor flow to the support/surface is continuously changed from θmin' to θmax' while the support l is being transported. %A
At least 7 types of nonmagnetic metal materials selected from 7 are formed as a vapor deposited film. The thickness of the non-magnetic metal vapor deposited film 3 is approximately 0.003~0.03 mm depending on conditions such as obtaining a sufficient protective effect and not reducing the output due to spacing loss due to the gap between the magnetic metal vapor deposit film 2 surface and the magnetic head. 0, /
By1. Preferably it is in the range of 0,001-0,02ttm.

The magnetic metal materials used in the present invention include:

Fee Cab Metal such as Ni or Fe (-
o 5Fe-Ni, C: o-Nib Fe-co-Ni
bFe-Rhs Fe-Cu, Co-cu%co-Au
s cOy, co Lah COPrs C0-Gd,
Co-8m5 Co-Pts Ni-Cu&Mn
-B i , Mn-8b, Mn-A/, Fe
-C7, Co-Cr5 Ni-Cr, Fe-Co-C
: rhNi-Co-CrsFe-Co-
It is a ferromagnetic alloy such as Ni-cr. Particularly preferred is co or an alloy containing 70% by weight or more of cobalt. The magnetic metal vapor deposition thin film formation may be carried out in an atmosphere containing a reactive gas such as oxygen.

Vapor deposition in the present invention refers to the above-mentioned U.S. Pat. No. 334L, 2
In addition to the normal vacuum evaporation described in the specifications of &3.2, the vapor flow is ionized and accelerated by electric fields, magnetic fields, electron beam irradiation, etc. to create an atmosphere with a large mean free path of the evaporated molecules. It also includes a method of forming a thin film on a supporting substrate using a method of forming a thin film on a supporting substrate. Special public Sho ga-2oara issue, Special public Sho da 7-, 24!72, Special public Sho 4c Ta 1μjμ32
No., JP-A-Sho Liter JJI-0 No., JP-A-Sho Liter-3143
No., Tokukai Sho≠2-J'3! An ionized vapor deposition method such as that shown in the above publication may also be used in the present invention.

Substrates used in the present invention include polyethylene terephthalate, polyimide, polyamide, polyvinyl chloride, cellulose triacetate, and polycarbonate.

Plastic bases such as polyethylene naphthalate are preferred.

In the magnetic recording medium of the present invention, a so-called pack layer may be provided on the lubricant layer or the back surface of the support, if necessary.

Further, a layer made of an organic or inorganic substance may be provided between the magnetic metal vapor deposited film and the support.

〔Example〕

The present invention will be specifically explained below using Examples.

It goes without saying that the present invention is not limited to these.

Example 1 Using a winding type vapor deposition apparatus whose main parts are shown in Fig. 2,
A magnetic tape was prepared by forming a dicobalt-deposited magnetic thin film on a polyethylene terephthalate film having a thickness of /, l, j μm by an oblique incidence deposition method. In FIG. 2, the belt-shaped support 21 is conveyed along a cooling channel, and a magnetic deposited film and a non-magnetic deposited film are formed on its surface by oblique incidence deposition. Vapor deposition material 23. λμ is charged to l2z and 2g, respectively, and heated and evaporated by suitable heating means. The angle of incidence of the vapor flow onto the support 2/ is determined by the deposition prevention plates 27, 21. It is controlled by λ. In this example, the polyethylene terephthalate film is
Co was evaporated from the crucible while being transported in the direction of , and a vapor-deposited magnetic film was formed by setting the incident angle θmax to 00% 0 min as jjo.

The setting of θmax is done using the adhesion prevention plate 27. The setting of θmin is performed on the adhesion prevention plate at. Next, while the polyethylene terephthalate film was conveyed in the direction of arrow B, Cr, Ti%, or Sn was evaporated from the crucible to form a nonmagnetic vapor deposited film. θrna X's θmin' set in the adhesion-proof plate core and the core were respectively set to 0%go°. The thickness of the magnetic deposited film was /000λ, and the thickness of the nonmagnetic deposited film was /JOA.

Comparative Example 1 A cobalt-deposited magnetic thin film was formed on a polyethylene terephthalate film in the same manner as in Example 1, and then Cr, Tin, or Sn was formed to the same thickness as in Example 1 by a conventional vacuum deposition method. That is, in Figure 1, the adhesion prevention plate 2t is removed and the cooling can 2-2 is removed.
Cr, Tit, or Sn vapor-deposited films were respectively formed on the vapor-deposited magnetic film of a polyethylene terephthalate film that was placed directly below the FC-Russe 30 and conveyed along arrow A from the FC-Rusze 30.

The weather resistance of the thus obtained magnetic tape after repeated running was measured. For weather resistance, use tape on VH8 type VTR! After running 0 times and storing the tape at a relative temperature of % to 0 c for a week, the occurrence of rust on the tape surface and the adhesion of the deposited film by cellophane tape peeling test were evaluated using J-grade evaluation. The measurement results are as follows.

Table 7 *J grade evaluation: (j is the best) Example 2 A winding type vapor deposition apparatus shown in Fig. 7g2 was used, and j tiy
A CoN1 (Ni) weight-sensitive vapor-deposited thin film was formed on a polyethylene terephthalate film with a thickness of H by an oblique incidence vapor deposition method to a thickness of /300λ.The polyethylene terephthalate film was transported in the direction of arrow A. The incident angle θmax in an atmosphere containing o2 gas is rA'
, 0m1n14'0', respectively, to form magnetic vapor deposited films.

Next, the nonmagnetic material was evaporated from Lutg2t to form a nonmagnetic vapor deposited film having a thickness of λOQA on the vapor deposited magnetic film. The non-magnetic material is Cr5Cu.

A7 is used, and the incident angles θmax' and θmin' set by the anti-deposition plate λ and 2t are to 0. to 0 and Lfc.

Comparative Example 2 A CoNi evaporated magnetic thin film was formed on a polyethylene terephthalate film in the same manner as in Example 2, and then Cr, Cu, or AJ was deposited to a thickness of 200A using the conventional vacuum evaporation method in the same manner as in Comparative Example 1. formed.

The weather resistance of the thus obtained magnetic tape after repeated running was measured in the same manner as in Example 1 and Comparative Example 1, and the results were as shown in Table 1.

Table - [Effects of the Invention] As described above, the magnetic recording medium according to the present invention is a metal thin film type magnetic recording medium with improved weather resistance after repeated running, and has great practical advantages as a single type magnetic recording medium. .

[Brief explanation of the drawing]

FIG. 1 shows an example of the structure of a magnetic recording medium according to the present invention. 1...Support, 2...Magnetic metal vapor deposited film, 3...Nonmagnetic metal thin film FIG. 2 shows a schematic diagram of an apparatus for producing the magnetic recording medium of the present invention. Thing...Strip support, 2.2...Cooling can. CoJ, 24A... Vapor deposition material. Koj, Koro, 30... Crucible. 27.21. Kota... Anti-adhesion plate

Claims (1)

[Claims] 1) A magnetic recording medium in which a vapor flow of a metal material evaporated from an evaporation source is deposited on a moving substrate,
By continuously changing the incident angle of the vapor flow of the magnetic metal material relative to the moving substrate from a high incident angle to a low incident angle, a magnetic metal vapor deposited film having a curved inclined columnar structure is coated with % relative to the moving substrate. 1. A magnetic recording medium comprising a non-magnetic metal vapor deposited film formed by continuously changing the incident angle of a vapor flow of a non-magnetic metal material from a low incident angle to a high incident angle. 2) Cr s T l s S as a non-magnetic metal material
n5Cu, AA! The magnetic recording medium according to claim 1, characterized in that at least seven types selected from the following are used.