JPS60205831A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To produce a magnetic recording medium by a vapor plating process with a small degree of curl by performing said vapor plating while >=300N/cm<2> stress is applying in the longer side direction of a supporter. CONSTITUTION:A nonmagnetic supporter 4 is drawn out of a reel 2A in a supply chamber 2 and taken up to a reel 3B. A heating means 5 set in a vacuum vapor deposition tank 1 heats the supporter 4 up to a prescribed temperature during its driving. A vapor deposition source 6 of a nonmagnetic metal of a low melting point and an evaporation source of a magnetic layer such as a Co evaporation source 7 are set under the means 5. A shielding plate 8 for steam current is added, and exhaust valves 9-11 are provided to each chamber. Then the supporter 4 is held at 140 deg.C under vacuum of 10<-5>Torr and then driven with 50N stress applied to the supporter 4 in its longer side direction. Then Bi is vapor- deposited on the supporter 4 by 200Angstrom thickness and then Co is vapor-deposited on the supporter 4 by 400Angstrom thickness. Then the supporter 4 is cooled. In such a way, a magnetic recording medium is produced with a small degree of curl.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method for manufacturing a magnetic recording medium.

BACKGROUND TECHNOLOGY AND PROBLEMS In recent years, magnetic thin film type magnetic recording media, that is, magnetic recording media in which a ferromagnetic a-film is formed on a non-magnetic support by methods such as vacuum deposition or sputtering, have been developed for the purpose of increasing the areal density of magnetic recording. There is a lot of research going on.

When a polymer film such as polyimide or polyamide is used as a non-magnetic support and a magnetic thin film is formed on the film to serve as a magnetic recording medium, the magnetic recording medium is generally placed with the surface on which the magnetic thin film is formed on the inside. When a magnetic recording medium having curls is used as a magnetic tape, the running performance of the tape and its contact with the magnetic heel become unstable, which poses a practical problem.

OBJECTS OF THE INVENTION In view of the above-mentioned points, the present invention provides a method for producing a magnetic recording medium that can produce a magnetic recording medium free of curl.

Summary of the Invention The present invention provides a method for manufacturing a magnetic recording medium in which a low melting point nonmagnetic metal and a magnetic metal are successively deposited on a nonmagnetic film support by so-called vapor phase plating such as sputtering. Vapor phase plating is performed with a tension of 30 ON/cJ or more being applied in the longitudinal direction of the support.

According to the present invention, a magnetic recording medium with extremely little curl can be easily obtained.

Example In the present invention, when a low melting point nonmagnetic metal and a magnetic metal are successively formed on a film-like nonmagnetic support by vapor phase plating such as vapor deposition or sputtering, the nonmagnetic support is A magnetic recording medium is produced by applying a tension of 30 ON/cIa or more in the longitudinal direction.

Examples of non-magnetic supports include polyimide, polyamide,
Polymer films such as polyamideimide and polyethylene terephthalate can be used. Examples of low melting point nonmagnetic metals include Bi+Ga and Sb.

Ge, Si+In, Pb+Sn+Zn, alloys thereof, intermetallic compounds, etc. can be used. As the magnetic metal, Co, Ni+Fe, or an alloy thereof (such as Co--Ni) can be used. In this way, when a low melting point nonmagnetic metal and a magnetic metal are successively vapor-phase plated while applying tension to a film-like nonmagnetic support, fine ranks tend to occur in the magnetic thin film, resulting in a magnetic recording medium with very little curl. is obtained.

In order to make the magnetic thin film have a rank of fineness, it can be achieved by heating the non-magnetic support of the polymer film to, for example, 100° C. or higher to form 81% magnetism, and then immediately cooling it.

FIG. 1 shows an example of a manufacturing apparatus to which the present invention is applied. In the figure, ζ, (1) is a vacuum deposition tank, (2) is a supply chamber that supplies a film-like non-magnetic support (4), and (3) is a winding chamber that winds up a non-magnetic support (4). It is. The nonmagnetic support (4) is unwound from the reel (28) of the supply chamber (2) and wound onto the reel (3^) of the winding chamber (3). In the vacuum deposition tank (1), a heating means (5) for heating the non-magnetic support (4) to a predetermined temperature is arranged in the middle of the movement of the non-magnetic support (4). A Bi evaporation source (6) and a magnetic layer evaporation source, such as a CO evaporation source (
7) is placed. (8) is a shielding plate that shields each metal vapor flow from the deposition sources (6) and (7) from each other. or(
01, Go) and (11) are exhaust valves for the vacuum deposition tank Tl), the supply chamber (2), and the winding chamber (3), respectively.

In this device, after the magnetic layer is deposited in a vacuum chamber (1) at a predetermined temperature, it is immediately cooled in a winding chamber (3).For example, cooling is performed by flowing cooling water into the reel (3A). I can also do things.

Next, an example will be described.

Example 1 Using the vapor deposition apparatus shown in Fig. 1, a non-magnetic support made of a polyimide film with a thickness of 12 μm and a diameter of 30 cm was prepared using a 1O-5T film.
The support temperature is maintained at 140° C. in a vacuum of
Bi was deposited on the support to a thickness of 200 layers while running the substrate while applying ON/c+il) in its longitudinal direction, followed by deposition of CO to a thickness of 400 layers, and immediately cooled after the deposition. The tension applied to the support was controlled by providing a brake on the supply reel shaft. The sample produced in this manner was referred to as Example 1.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the tension applied to the nonmagnetic support was 5 Newtons (therefore, 14 ON/cJ per unit area) and that rapid cooling after vapor deposition was not performed. The sample prepared in this manner was designated as Comparative Example 1.

Each sample on each side was cut into 2-inch pieces to obtain each magnetic tape, and the degree of curl in the middle direction was measured. As shown in Fig. 2, the measurement method is to form a magnetic thin film (23) on a sample, that is, a polyimide film (22) cut into 2-inch pieces on a flat substrate (21). 24): 6, and set the curl amount to the height d at the end.
It was evaluated by The curl measurement results are shown in Table 1.

Table 1 As is clear from Table 1, the magnetic recording medium of Example 1 has extremely little curl. The reason for the decrease in curl is not clear, but by applying tension during vapor deposition, fine racks are more likely to occur in the magnetic thin film, and this crank reduces the strain that occurs during the formation of the magnetic thin film, reducing stress on the non-magnetic support. It is thought that this is because the curls are reduced because the curls are no longer added.

By creating a magnetic recording medium with extremely little curl in this manner, when used as a magnetic tape, the running properties of the tape and the contact with the magnetic head become stable, which is of great practical benefit.

Furthermore, it is a great industrial advantage that a curl-free magnetic recording medium can be obtained without any special treatment after the magnetic thin film is formed.

Note that although the magnetic thin film was formed on the upper side by vapor deposition, the present invention can also be applied to other cases in which it is formed by sputtering or the like.

Effects of the Invention According to the present invention, when a low melting point nonmagnetic metal and a magnetic metal are continuously vapor-phase plated on a nonmagnetic filter-like support, the non-magnetic film-like support is coated with 30ON/C11! By performing vapor phase plating with the following tension applied in the longitudinal direction, a magnetic recording medium with very little curl can be easily obtained without any special treatment after the magnetic thin film is formed.

[Brief explanation of drawings]

FIG. I is a block diagram showing an example of a manufacturing apparatus used for manufacturing the magnetic recording medium of the present invention, and FIG. 2 is a cross-sectional view for explaining curl measurement. (11 is a vacuum deposition tank, (2) is a supply chamber, (3) is a winding chamber, (4) is a film-like nonmagnetic support, (5) is a heating means, (6) is a low melting point nonmagnetic metal The vapor deposition source (7) is a magnetic metal vapor deposition source.

Claims (1)

[Claims] In a method for producing a magnetic recording medium in which a low melting point nonmagnetic metal and a magnetic metal are successively formed on a nonmagnetic film support by vapor phase plating, the support is coated with 30ON/ai1 during formation.
A method for manufacturing a magnetic recording medium, characterized in that the above tension is applied in the longitudinal direction of the support.