JPH0198126A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain good orientational property without requiring a special orienting device by passing current to striped thin metallic films provided on a magnetic recording medium to generate a magnetic field in the longitudinal direction, thereby orienting the films. CONSTITUTION:The many striped thin metallic films 12 extending in the short side direction of a base film 10 which is a high-polymer molding are longitudinally arranged at prescribed intervals. A thin nonconductive film 14 is then applied on the films 12 to smooth the surface; thereafter, a thin ferromagnetic film 16 is formed thereon. A pair of electrodes 18, 20 are brought into contact with the surfaces of both exposed ends of the films 12. While the recording medium formed by forming the films 12 and the film 14 on the film 10 under generation of the evaporated electrons from an evaporation source is run in the longitudinal direction thereof, the current is passed through the electrodes 28, 20. The current flows only to the films 12 and the magnetic field H is generated in the longitudinal direction of the film 10. A film 16 is, therefore formed while the evaporated atoms to be deposited by evaporation are immediately oriented on the film 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a magnetic recording medium such as a magnetic tape for audio or video use.

[Conventional technology]

Conventionally, in the method of manufacturing a magnetic recording medium by forming a ferromagnetic vapor-deposited thin film on a substrate made of a polymer molded product, the coercive force (Hc) in the longitudinal direction of the ferromagnetic thin film is improved, that is, magnetic anisotropy is improved. As means for obtaining this, oblique evaporation, magnetic field evaporation, and the like are known.

[Problems to be solved by the invention]

The magnetic field deposition method uses permanent magnets or electromagnets for boat fishing, but it is difficult to make the part that generates the magnetic field touch the part where you want to apply the magnetic field, so the distance between the two must be shortened to a certain extent. I can't. Therefore, if a permanent magnet is used, it needs to be quite strong, and if an electromagnet is used, a strong current must be passed, which requires a large-scale device, so the above-mentioned deposition method in a magnetic field is not generally used. do not have. On the other hand, the oblique evaporation method is commonly used because it does not require such a magnetic field generator and can obtain relatively good magnetic anisotropy, but it is said to have lower deposition efficiency than evaporation in a magnetic field. There was a problem.

[Means and effects for solving the problem] The present inventors have made extensive studies to improve the coercive force in the longitudinal direction of a ferromagnetic thin film provided on a polymer molded substrate of a magnetic recording medium. , by passing a current through the striped metal thin film provided on the magnetic recording medium, a magnetic field is generated in the longitudinal direction and the magnetic recording medium itself is given the role of an orientator. The present invention has been completed by making it possible to improve the coercive force.

That is, according to the present invention, in a method for manufacturing a magnetic recording medium, in which a magnetic layer is provided on a polymer molded substrate and orientation is performed in the magnetic layer, a large number of magnetic recording media extending in the transverse direction on the polymer molded substrate are provided. metal thin films are provided at predetermined intervals,
After providing a non-conductive thin film thereon, when forming a ferromagnetic thin film on the non-conductive thin film, a magnetic field is generated in the longitudinal direction of the polymer molded substrate by passing an electric current through the metal thin film. , there is provided a method for manufacturing a magnetic recording medium, characterized in that the above orientation is performed.

The present invention generally applies Ampere's law, which states that when a current flows, a magnetic field is generated in the direction of rotation of a right-handed screw relative to the direction of the current. That is, by passing a direct current through a metal thin film on a magnetic recording medium in the lateral direction of the metal thin film, a longitudinal magnetic field is generated, forming a magnetic layer and simultaneously causing orientation in the magnetic layer.

〔Example〕

Embodiments of the method for manufacturing a magnetic recording medium of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view for explaining one embodiment of the present invention. Introduction: Base film 1, which is the base of the polymer molded product.
A metal (conductive) thin film is provided discontinuously on one surface of the wire. That is, a large number of striped metal thin films 12 extending in the transverse direction of the base film 10 are arranged in the longitudinal direction at predetermined intervals. The striped metal thin film 12 may be made of any conductive material such as aluminum, copper, silver, etc. The material to be used may be determined as appropriate after considering cost, durability, physical characteristics, etc. . The metal thin film 12 may be formed by any method such as vapor deposition, sputtering, ion blating, and electroless plating.

The method for forming the striped metal thin film 12 is, for example,
Possible methods include a method in which the slit is made to travel near the vapor deposition formation line in synchronization with the travel speed of the base, a method in which the slit is formed by opening and closing a shutter, and the like. However, the thickness of the metal thin film 12 is set to a necessary thickness in consideration of the thickness dependence of electrical resistance.

Next, a ferromagnetic thin film 1 is formed on the striped metal thin film 12.
6, if the ferromagnetic thin film 16 is formed directly on the striped metal thin film 12, the ferromagnetic thin film 16 is formed while maintaining the shape of the striped metal thin film 12, which poses a practical problem. Moreover, if the ferromagnetic thin film 16 itself has conductivity, a continuous conductive thin film will be formed, and considering that a current will be passed through the striped metal thin film 12 in a later process, the It is not practical because it is necessary to suppress discharge and contact. Therefore, a non-conductive thin film 14 is provided between the striped metal thin film 12 and the ferromagnetic thin film 16. This coating with the non-conductive thin film 14 not only has the effect of preventing the striped metal thin film 12 and the ferromagnetic thin film 16 from coming into contact with each other, but also has the advantage that the coating surface becomes smooth. The above-mentioned non-conductive substance may be a binder used in magnetic tapes, for example, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-vinylidene chloride copolymer, etc.
Examples include acrylonitrile copolymers, polyamide resins, polyester resins, epoxy resins, phenolic resins, and polyurethane resins.

After coating the non-conductive thin film 14 and smoothing the surface, a pair of electrodes 18 and 20 are placed on both exposed ends of the striped metal thin film 12 when forming the ferromagnetic thin film 16 thereon. bring into contact. Next, from the evaporation source,
The striped metal thin film 12 and the non-conductive thin film 14 formed on the base film 10 are moved in the longitudinal direction while generating evaporated atoms, and the electrode 18
A direct current I is passed through the terminal. This current I is the electrode 1
8.20, a magnetic field H is generated in the longitudinal direction of the striped metal thin film 12 and the non-conductive thin film 14 formed on the base film 10. Therefore, the evaporated atoms are immediately oriented on the non-conductive thin film 14, forming the ferromagnetic thin film 16. Magnetic field H generated by current I
is inversely proportional to the distance from the current I, but this distance depends on the thickness of the non-conductive thin film 14, which is very thin at a few μm, so it is possible to generate a large magnetic field with a relatively small current. It is.

Further, the method for forming the ferromagnetic thin film 16 may be any one of vapor deposition, sputtering, ion blasting, low'tL vapor phase growth, and the like. In this specification, these methods are collectively referred to as vapor deposition.

Incidentally, during the formation of the ferromagnetic thin film 16, the ferromagnetic thin film 16 is deposited on the exposed portions of both ends of the striped metal thin film 12 formed on the upper side of the non-conductive thin film 14 in the figure, and a pair of ferromagnetic thin film 16 are deposited to prevent the ferromagnetic thin film 16 from being formed. It is necessary to shield with a shielding plate (not shown). That is, if it is not shielded, the ferromagnetic thin film 16 will be formed to cover the electrodes 18, 20 and the striped metal thin film 12, and as mentioned above, it will be necessary to suppress discharge and contact at each part, which is impractical. . Furthermore, even if a continuous metal thin film is used in the longitudinal direction without using the striped metal thin film 12, if the parts other than the electrodes 18 and 20 are electrically floating, the same result as when the striped metal thin film 12 is used. Although it is expected to be effective, it is not practical because it is necessary to suppress electrical discharge in each part.

To explain the above embodiment in more detail together with comparative examples, as shown in FIG. obtain. The striped metal thin film 12 was formed of aluminum with a thickness of 1 μm on the polyester base film 10, and the non-conductive thin film 14 was formed thereon, but the non-conductive material was vinyl chloride-vinyl acetate copolymer. The thickness was set to 2 μm. Further, as the metal for the ferromagnetic thin film 16, Co-Ni (Ni20wt
%) alloy was used, and the thickness was 2000 mm. At this time, a pair of electrodes 18 and 20 were placed at both ends of the striped metal thin film 12, and a direct current IA was applied to generate a magnetic field to form the ferromagnetic thin film 16.

In this method, the film is completed when vapor deposition and orientation have been performed over the entire length of the long film, and it can be used as is by slitting it.

Comparative Example The continuous deposition of the ferromagnetic thin film 16 described above was carried out without applying the current I to the striped metal thin film 12, and after the completion of the deposition, the current I was applied to effect orientation, but the same materials as in the above case were used. A long film was obtained by the same treatment.

From the relationship between the magnetic tape obtained in the above example and the comparative example,
While the Hc in the longitudinal direction of the comparative example was 1000e, the Hc of the above example was 4500e, indicating that the magnetic recording medium produced by the manufacturing method of the present invention has excellent magnetic properties. is clear.

FIG. 3 is a plan view illustrating another embodiment of the present invention.

In this embodiment, a plurality of pairs of electrodes are used, which are connected in series. That is, the plurality of + side electrodes 18a, 1
8b, 18c, 18d and a plurality of one side electrodes 20a, 20b
, 20c, and 20d are arranged in pairs in the longitudinal direction of the base film 10, and are connected to adjacent electrodes of opposite polarity by conductive wires 22, forming a series electrode as a whole. When an electric current is applied to the striped metal thin film 12 shown in FIG. 1 using an electrode having such a configuration, the range in which the magnetic field H is generated becomes wider, so that the orientation efficiency increases.

〔Effect of the invention〕

As is clear from the above description, in the method for manufacturing a recording medium according to the present invention, a magnetic field is generated and oriented by passing a current through a striped metal thin film on a substrate.
It becomes possible for the recording medium itself to function as an orientator, and therefore no special orientator is required. In addition, since the manufactured metal media have good orientation, the coercive force in the longitudinal direction (
Since the present invention has an excellent feature of improving Hc), the industrial applicability of the present invention is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a perspective view for explaining one embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. FIG. 2 is a plan view showing an example. 10...Base film, 12...Gold m, FI! ,
14... Non-conductive thin film, 16... Ferromagnetic thin film, 18
, 18a, 18b, 18c, 18d,
20° 20a, 20b, 20c, 20d...electrodes,
22...Conducting wire. Inventor: Koi Horiguchi, Kuni Moto, Haruide, applicant: Victor Japan Co., Ltd.

Claims (5)

[Claims] (1) A method for manufacturing a magnetic recording medium in which a magnetic layer is provided on a polymer molded substrate and orientation is performed in the magnetic layer,
A large number of metal thin films extending in the transverse direction are provided on the polymer molded substrate at predetermined intervals, a non-conductive thin film is provided thereon, and then a ferromagnetic thin film is formed on the non-conductive thin film. A method for producing a magnetic recording medium, characterized in that the orientation is performed by generating a magnetic field in the longitudinal direction of the polymer molded substrate by passing a current through the metal thin film. (2) The method of manufacturing a magnetic recording medium according to claim 1, wherein the ferromagnetic thin film is formed by vapor deposition. (3) When passing the current, a direct current is passed in the transverse direction using electrodes that are in contact with both ends in the transverse direction of the polymer molded substrate of the metal thin film, and the polymer molded substrate is 2. The method of manufacturing a magnetic recording medium according to claim 1, wherein the magnetic recording medium is moved in the longitudinal direction. (4) The method for manufacturing a magnetic recording medium according to claim 1, characterized in that the electrodes include a plurality of pairs of electrodes connected in series and arranged in the longitudinal direction. (5) The method for manufacturing a magnetic recording medium according to claim 1, wherein the metal thin film through which the current flows is striped in parallel to each other.