JPS61240437A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain the titled magnetic recording medium having stabilized magnetic characteristics and form by treating a substrate with glow discharge immediately before the substrate begins to contact a preheating roller when a metallic thin film magnetic layer is formed by vapor deposition. CONSTITUTION:A substrate 1 of a high molecular material is treated with glow discharge by a glow discharge electrode 8 immediately before the substrate begins to contact a preheating roller 3. The glow discharge electrode 8 is arranged so that the glow discharge is exerted on the part of the substrate 1 which begins to contact the preheating roller 3. The surface conditions of the substrate 1 are made uniform by the passage of the substrate 1 through a gas under the influence of the glow discharge and the electrification of the substrate 1 is removed. Consequently, the sticking of the substrate 1 on a can 2 is made uniform, a magnetic recording medium without any creases and having uniform characteristics can be obtained. Ar or N2 is preferably used as the gas to be introduced into a vacuum vessel in consideration of its stability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a magnetic recording medium in which a metal wIWA magnetic layer is formed on a substrate made of a polymeric material either directly or via an underlayer.

Conventional technology Conventionally, coated magnetic recording media have been used in which magnetic powder is coated on a non-magnetic substrate, but in order to achieve higher recording density, metal W@ WiI! film formed by vacuum evaporation method! The II type is being put into practical use.

As a method for forming a metal thin film magnetic layer on a substrate made of a polymeric material using a vacuum evaporation method, the best method is to perform evaporation while moving the substrate along the circumferential surface of a cylindrical can. FIG. 3 schematically shows the internal structure of a vacuum evaporation apparatus using such a method. A substrate 1 made of a polymer material runs along a preheating roller 3 and then runs along the circumferential surface of a heated cylindrical can 2 in the six directions of arrows. The reason for raising the temperature of the cylindrical can 2 is to improve the magnetic properties of the magnetic layer. That is, in any metal thin film magnetic layer for in-plane recording or perpendicular magnetic recording, the higher the substrate temperature during deposition, the higher the coercive force and the better the recording and reproducing characteristics.

For example, when forming a co-Qr alloy film for perpendicular magnetic recording as a magnetic layer, in order to obtain satisfactory recording and reproducing characteristics,
It is necessary to raise the temperature of the circumferential surface of the cylindrical can to 200°C to 300°C. Additionally, the preheating roller 3 is necessary to prevent wrinkles in the medium.

That is, without the preheating roller 3, when the substrate 1 at room temperature begins to come into contact with the heated cylindrical can 2, wrinkles would occur due to the sudden temperature change. The cylindrical can 2 is heated after being preheated by the preheating roller 3.
When the substrate 1 starts to come into contact with the cylindrical can 2, the substrate 1 runs along the cylindrical can 2 without wrinkles, and a magnetic layer is formed by the evaporation source 7. 4.5 is a supply roll and a take-up roll for the substrate 1, respectively, and 6 is a free roller.

Problems to be Solved by the Invention When a magnetic layer is formed on a substrate made of a polymeric material using a vacuum evaporation apparatus as shown in FIG. It is difficult to obtain membranes. To explain this with an example, a Co-Cr perpendicular magnetic anisotropic film, which is well known as a perpendicular magnetic recording medium, is fabricated using the vacuum evaporation apparatus shown in Fig. 3. When we measured the longitudinal distribution of coercive force, we found a significant change as shown in Figure 4. Also in the width direction, the coercive force in the vertical direction changed as shown in FIG. The reason for this is considered to be temperature irregularities in the substrate 1 caused by uneven contact between the substrate 1 and the can 2, with some portions of the substrate 1 being in close contact with the can 2 and other portions not being in close contact with the can 2. As described above, in addition to the fact that the magnetic properties are not uniform, wrinkles tend to occur in the deposited area, making it difficult to produce a medium with stable magnetic properties and shape.

An object of the present invention is to provide a method for manufacturing a metal thin film magnetic recording medium having stable magnetic properties and shape.

Means for Solving the Problems The method for manufacturing a magnetic recording medium of the present invention includes running a polymeric material substrate along a preheating roller and then running it along the circumferential surface of a cylindrical can whose temperature has been raised. Gold Iil is deposited on the substrate at the cylindrical can position either directly or through an underlayer.
Thin! 11! When forming the l-type layer by vacuum evaporation method,
The method is characterized in that the substrate is subjected to a glow discharge treatment immediately before the substrate starts coming into contact with the preheating roller.

Effect: According to this configuration, the substrate is subjected to glow discharge treatment immediately before it starts to come into contact with the preheating roller (the term "immediately before" here includes the part where it starts to come into contact with the preheating roller), so that the surface condition of the substrate becomes uniform. Further, due to the neutralization effect of the glow discharge, the charge on the substrate is removed and the substrate uniformly adheres to the preheated roller and can, resulting in a wrinkle-free magnetic recording medium with uniform characteristics.

EXAMPLE Hereinafter, the manufacturing method of the present invention will be explained based on a specific example.

FIG. 1 shows a vacuum evaporation apparatus for carrying out the manufacturing method of the present invention. Components having the same functions as those in FIG. 3 are given the same reference numerals. The only difference from FIG. 3 is that the glow discharge treatment is performed by the glow discharge electrode 8 immediately before starting. By supplying power to the glow discharge electrode 8 and adjusting the degree of vacuum, glow discharge is generated near the electrode. Note that the glow discharge electrode 8 is arranged so that the glow discharge also extends to the portion where the substrate 1 begins to come into contact with the preheating roller 3 .

By passing the substrate 1 through the gas in this glow discharge state, the surface condition of the substrate 1 becomes uniform, and the substrate 1
The electrical charge is removed. As a result, board 1 to can 2
The adhesion becomes uniform, and a magnetic recording medium with uniform properties and no wrinkles can be obtained.

There are various types of glow discharge, including direct current, alternating current, high frequency, and magnetron type, and any of these types may be used. As the gas introduced into the vacuum chamber to generate glow discharge, A or N2 is preferable from the viewpoint of stability.

In addition, as shown in FIG. 5, the glow discharge electrode is attached to the substrate 1.
If it is installed away from the vicinity of the entrance to the preheating roller 3, the above-mentioned effect will be significantly reduced. This is because before the substrate 1 that has been subjected to the glow discharge treatment begins to come into contact with the preheating roller 3, it comes into contact with the gas in the vacuum chamber and the free roller 9, so the effect of the glow discharge treatment is weakened and the preheating It is thought that this is because the adhesion to the roller 3 becomes non-uniform, which causes the adhesion to the cylindrical can 2 to become non-uniform as well.

Further, although a considerable effect can be seen even if the glow discharge treatment is applied only to one side of the substrate 1, it is preferable to apply the glow discharge treatment to both sides of the substrate 1 as shown in FIG. Furthermore, as shown in Figure 2,
The inside of the vacuum chamber 11 is partitioned into a glow discharge processing section B and a vapor deposited film forming section C using a partition plate 10, and the vacuum degree of the vapor deposited film forming section C is maintained at a higher degree of vacuum than that of the glow discharge processing section B. Improves magnetic properties. In Figure 2,
12 is an exhaust pump.

Further, by applying a voltage between the magnetic layer and the circumferential surface of the can 2, the adhesion of the substrate 1 to the can 2 is improved, and a more stable medium can be obtained.

Note that when producing a Go-Cr perpendicular magnetic anisotropic film by vacuum evaporation, it is necessary to raise the temperature of the can 2 as described above, so the present invention is particularly effective in this case. .

Next, more specific experimental examples of the present invention will be explained.

[Experiment example] Using the vacuum evaporation apparatus shown in Fig. 2, a polyimide film with a thickness of 10 μm was used as the substrate 1, and a Co-Cr perpendicular magnetic anisotropic film with a thickness of 3000 A was formed thereon as a magnetic layer. did. A high frequency power source of 13 fSMHz was used as the power source for glow discharge, and the electrode 8 for glow discharge was installed just before the polyimide film started to come into contact with the preheating roller 3.

In order to generate glow discharge, A' is introduced from near the glow discharge electrode, and the degree of vacuum near the glow discharge part is set to 0.
It was set to 017orr. In this state, the degree of vacuum near the vapor deposited film forming part was 1.2X 1G-' T Orr. Further, the temperatures of the peripheral surfaces of the preheating roller 3 and the can 2 were set to 150°C and 260°C, respectively. Further, a voltage of 120 volts was applied between the circumferential surface of the can 2 and the Co--Cr perpendicular magnetic anisotropic film.

The film thus formed had no wrinkles, had uniform properties in the length direction and width direction, and had excellent properties as a perpendicular magnetic recording medium. On the other hand, when the glow discharge treatment was not performed, a film with uniform characteristics in the length and width directions could not be obtained. Note that, as mentioned above, instead of directly forming a co-Cr film on the polyimide film, a Co-
A similar effect was observed when forming an Or film.

As described in the detailed description of the invention, the method for manufacturing a magnetic recording medium of the present invention involves subjecting the polymer material substrate to a glow discharge treatment immediately before the polymer material substrate starts contacting the preheating roller, and discharging the polymer material substrate at a cylindrical can position. Gold li! directly on top or through the base layer! In order to vacuum-deposit a thin film magnetic layer, glow discharge treatment is applied to the substrate just before it starts contacting the preheating roller (here, "immediately" includes the part where it starts contacting the preheating roller), which changes the surface condition of the substrate. In addition, due to the neutralization effect of glow discharge, the charge on the substrate is removed and the substrate adheres uniformly to the preheating roller and can, and the completed magnetic recording medium has no wrinkles on the polymer material substrate and has a long length. The magnetic layer had uniform characteristics in the direction and width direction.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of a vacuum evaporation apparatus for carrying out the manufacturing method of the present invention, FIG. 2 is a configuration diagram of another embodiment of FIG. 1, and FIG. 3 is a configuration diagram of a conventional vacuum evaporation apparatus. FIG. 4 is an explanatory diagram showing the unevenness of coercive force when a magnetic layer is deposited by a conventional method, and FIG. 5 is an explanatory diagram of the arrangement position of the glow discharge electrode in FIG. 1. 1... Polymer material n substrate, 2... Cylindrical can, 3...
... Preheating roller, 4 ... Supply roll, 5 ... Winding roll, 7 ... Evaporation source, 8 ... Glow discharge electrode, 10 ... Partition plate, 11 ... Vacuum chamber , B...
Glow discharge processing section, C...Deposited film forming section representative Yoshihiro Morimoto Figure 1 Figure 3 Figure 4 Length 2 (-) Figure 5

Claims (1)

[Claims] 1. After the polymer material substrate is run along a preheating roller, the polymer material substrate is run along the circumferential surface of a heated cylindrical can and directly onto the substrate at the position of the cylindrical can. Alternatively, a method for manufacturing a magnetic recording medium in which a glow discharge treatment is applied to a substrate immediately before the substrate starts contacting the preheating roller when forming a thin metal magnetic layer via a base layer by vacuum evaporation. 2. The method for manufacturing a magnetic recording medium according to claim 1, wherein glow discharge treatment is performed on both sides of the substrate. 3. A method for manufacturing a magnetic recording medium according to claim 1, characterized in that the glow discharge treatment and the deposition of the magnetic layer are performed in separate chambers having a pressure difference between the two chambers in a vacuum chamber. . 4. The method of manufacturing a magnetic recording medium according to claim 1, characterized in that the potentials of the magnetic layer and the circumferential surface of the cylindrical can are made different. 5. The method for manufacturing a magnetic recording medium according to claim 1, characterized in that Ar or N_2 is used as the gas for glow discharge. 6. The method of manufacturing a magnetic recording medium according to claim 1, characterized in that a Co--Cr perpendicular magnetic anisotropic film is used as the magnetic layer.