JPS60211640A - Manufacture of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium which is excellent in still endurance and corrosion resistance through simple treatment, by forming a magnetic layer on a nonmagnetic substrate by a vapor deposition method, and then, performing heat treatment together with or after ion bombarding treatment. CONSTITUTION:Ion bombarding treatment is performed on a magnetic tape A formed by a vapor deposition method while the magnetic tape A is wound by a winding roll 4 through a feeding roll 2 and rotary heating roll 3 in a chamber 1 under a condition where oxygen gas is introduced (at pressure of 0.1-1Torr) into the chamber 1 through a pipe 6 after the air is removed from the chamber 1, by applying a voltage of about 500V across bombarding electrodes 5. At the same time, heat treatment is performed at 60-120 deg.C by means of the heating roll 3. Therefore, a magnetic recording medium which is excellent in the still endurance and corrosion resistance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a magnetic recording medium, particularly a method for manufacturing a metal thin film type magnetic recording medium.

[Prior art and its problems]

In recent years, for high-density recording, metal thin film magnetic recording media, such as so-called vapor-deposited tapes, have been developed in which a magnetic material is deposited on a polyester film to form a ferromagnetic thin film layer.

However, in the conventional metal thin film type magnetic recording medium, which is different from the vapor-deposited tape, the vapor-deposited magnetic thin film layer is adversely affected by the contact action with the high-speed rotating head, that is, the magnetic thin film layer is damaged.

Therefore, in order to eliminate these drawbacks, research has been conducted to provide various protective films on the vapor-deposited magnetic thin film layer, but the adhesion to the vapor-deposited magnetic thin film layer is not sufficient and there is also the problem of spacing loss. Therefore, conventional protective films are not sufficiently effective.

[Disclosure of the invention]

The present inventor has developed a type of magnetic recording medium in which a ferromagnetic thin film layer is provided on a non-magnetic substrate by a paper deposition method such as vacuum evaporation, a so-called metal thin film magnetic recording medium.
For example, by performing ion bombardment treatment in an active gas atmosphere such as oxygen or ozone, and performing heat treatment at the same time or after the ion bombardment treatment, an effective protective film can be formed on the surface of the ferromagnetic thin film layer on the nonmagnetic substrate. It has been found that a metal thin film magnetic recording medium on which, for example, an oxide film is formed and which has been subjected to such surface treatment, has excellent, for example, methyl resistance or corrosion resistance.

Similarly, ion bombardment is preferably carried out in an oxidizing atmosphere such as oxygen or ozone. For example, when ion bombardment is carried out in a nitrogen gas atmosphere, there are problems in terms of corrosion resistance and methyl resistance. Ion bombardment under a gas atmosphere is not trivial.

[Example 1] FIG. 1 is a schematic explanatory diagram of a surface treatment apparatus used in carrying out the method for manufacturing a magnetic recording medium according to the present invention.

In the same figure, Δ is, for example, a 12 μm thick polyester film, and a Co-Ni magnetic alloy (Co:Ni = 80:20) is 150
The magnetic tape is a metal thin film type magnetic tape deposited with a thickness of 0A, and this magnetic tape A is arranged so as to be wound from a supply roll 2 in a chamber 1, through a rotating heat roll 3, and onto a take-up roll 4.

Reference numeral 5 denotes a bombardment electrode provided at a predetermined position near the rotating heat roll 3, and by applying a voltage to the bombardment electrode 5 under predetermined conditions, the surface of the magnetic thin film layer of the magnetic tape undergoes ion bombardment treatment. It looks like this.

That is, first, after evacuating the inside of the chamber 1, an active gas such as oxygen gas is introduced from the oxygen gas introduction pipe 6, and the inside of the chamber 1 is heated to about 0.1 to 1" orr, for example about Q, 2 Torr. A bombarded electrode, a pole 5
Ion bombardment is carried out by applying a voltage of about 300 to 1000 V, for example about 500 V, to the substrate.

Similarly, a rotating heat roll 3 is arranged near the bombardment electrode 5, and since the magnetic tape A is sent to the take-up roll 4 via the rotating heat roll 3, heat treatment is not performed during the ion bombardment process. That is, the magnetic tape A is subjected to a heat treatment using a rotating hot roll 3 heated to, for example, 40 to 120 DEG C., preferably about 60 to 120 DEG C., for example, 90 DEG C., at the same time as the ion bombardment treatment.

Metal thin film magnetic recording media whose magnetic layer has been surface-treated as described above are superior to conventional metal thin film magnetic recording media. While the still time of a thin film magnetic recording medium is only 3 minutes, the metal thin film magnetic recording medium of this example has a methyl time of over 40 minutes.
Furthermore, when a rigidity test was conducted in an environment with a temperature of 40°C and a humidity of 9Q% RI, spot-like rust appeared in three days with the conventional metal thin film magnetic recording medium, but with this example, rust appeared in three days. In the metal thin film type magnetic recording medium, no foreign liquid was observed even after two weeks had passed.

Embodiment 2] FIG. 2 is an explanatory diagram of a surface treatment apparatus used for carrying out the method for manufacturing a magnetic recording medium according to the present invention, and the same numbers as those in FIG. shows.

In FIG. 2, 3' is a rotating heat roll similar to the rotating heat roll 3, and 7 is a guide roll.

After the magnetic thin film of the magnetic tape A is subjected to the same surface treatment as in the above embodiment, it is subjected to a heat treatment by a rotating heat roll 3' heated to 90°C.

The metal thin film type magnetic recording medium in which the magnetic layer has been surface-treated as described above is even better than that of the embodiment described above, that is, it has a methyl time of 60 minutes or more, and has a long durability. Even in the MLL test, no abnormality was observed even after 3 weeks or more.

〔effect〕

A magnetic thin film layer with excellent still resistance and mechanical properties, for example, can be obtained.

In the manufacturing process, only a simple process is added compared to the conventional one, and the cost increase due to this additional process is minute, and a 7J recording medium can be obtained at a low cost.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams of a surface treatment apparatus used in carrying out the present invention. A... Magnetic tape, 3, 3'... Rotating heat roll, 5
...Bombarded electrode. Patent applicant: Victor Japan Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] A method for manufacturing a magnetic recording medium, which comprises forming a magnetic layer on a non-magnetic substrate by a paper deposition method, followed by ion bombardment and heat treatment at the same time or after the ion bombardment.