JPS63164024A - Method for manufacturing magnetic recording media - Google Patents

Abstract

PURPOSE:To permit formation of medium forming layers on both faces of a substrate by a simple mechanism with high efficiency by twisting the substrate so that the front and rear of the substrate are simultaneously opposed to vapor sources. CONSTITUTION:A base film 3 which is held between a substrate feed roll 1 and a substrate take-up roll 2 is once twisted by guide rolls 4 to the state known as a 'Mobius band'. As a result, both the front and rear of the film 3 are opposed to the vapor sources 5, 6 simultaneously. A degassing treatment is executed in this state and thereafter, a ferromagnetic metallic film consisting of Co-Cr is formed on the base film from the vapor source 5 and Si is deposited thereon by evaporation from the vapor source 6 to form a protective layer. After the film is passed through the guide rolls 4, the similar recording layer and protective layer are formed on the opposite side in the same vacuum. The recording layers are, therefore, formed by the simple mechanism with the >=2 times higher efficiency than heretofore.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a magnetic recording medium, and particularly to a method for manufacturing a magnetic recording medium suitable for making the mechanical properties and magnetic properties uniform on both sides of the magnetic recording medium. Regarding the manufacturing method, it is suitable for use in a perpendicular magnetic recording medium having a magnetic recording film made of a CO-Cr alloy.

[Conventional technology]

In recent years, there has been a great desire for higher storage capacity in magnetic recording devices, and efforts are being made to put into practical use recording media whose recording film is a ferromagnetic metal thin film formed by vacuum evaporation, sputtering, ion blating, etc. Efforts are being made. However, recording media using this metal thin film still have some problems in practical use, and in particular, improvement of corrosion resistance and sliding resistance is an important issue that needs to be solved immediately.

By the way, when a medium is destroyed, there are generally two patterns: In other words, when the head and the medium come into contact and slide, wear progresses from the surface of the medium, leading to destruction.In other cases, peeling occurs at the interface between the medium substrate and the forming layer thereon, resulting in destruction. be.

Therefore, in order to prevent the former type of destruction, a protective lubricant layer has been provided on the magnetic recording medium to improve the wear resistance of the medium. (For example, JP-A-53-40505) However, in order to improve the durability of the medium as well as improving the wear resistance of the medium surface, it is necessary to improve the adhesion between the substrate and the magnetic recording film and prevent peeling from the substrate. It is essential to eliminate destruction caused by

Therefore, in order to improve the adhesion between the medium forming layers, a method is known in which a metal magnetic thin film layer, a metal oxide layer, and a higher fatty acid-based lubricant layer are continuously formed on a substrate in the same vacuum. (JP-A-59-154642) [Problems to be Solved by the Invention] It is true that the above method improves the adhesion between the medium forming layers on one side of the medium. By the way, polymeric materials such as polyimide used as base films of magnetic recording media exhibit hygroscopicity at room temperature and generate gas at high temperatures.

Therefore, when a medium is produced by a paper deposition method such as a vacuum evaporation method using a polymeric material that is not subjected to degassing treatment as a base film, the following problem occurs. That is, during the formation of the medium, the temperature of the surface of the base film increases, so gas such as H20 is generated from the film. Since this occurs between the base film and the formed thin film, the adhesion between the base film and the formed layer decreases. When the method according to JP-A-59-15462 is used, the adhesion between the medium forming layers is improved, but the adhesion between the base film and the medium forming layer is reduced due to the above-mentioned reasons.

As a result, the durability and strength of the magnetic recording medium may be significantly reduced. Next, if the base film is degassed in advance to produce the medium, there will be no reduction in adhesion due to the degassing phenomenon. By the way, in order to realize a magnetic recording medium capable of single-sided recording and reproduction, it is necessary to form medium forming layers such as magnetic recording layers on both sides of the base film. However, when a medium is generally produced by the paper deposition method, after one side of the medium is formed in the same vacuum, the medium is taken out of the vacuum once, and then set in the device again to form another side of the medium in vacuum. . Therefore, when forming a medium on the second side, if the degassing treatment is not performed again, the adhesion between the base film and the medium forming layer on which the medium was formed the second time will deteriorate, and the durability of the magnetic recording medium will deteriorate. There is a good chance that the strength will decrease.

To solve this problem, after degassing the base film once, a medium is continuously formed on both sides of the base film in the same vacuum, so that the base film absorbs HxO in the air. It is important to eliminate opportunities to do so. By the way, in order to form medium forming layers on both sides of a substrate in the same vacuum, there are two possible methods: providing evaporation sources on both sides of the substrate, or providing a mechanism that allows the substrate to face the evaporation source in a vacuum. It will be done. However, using more than one method may result in an increased size and complexity of the device.

Therefore, an object of the present invention is to provide a method for forming medium forming layers on both sides of a substrate in the same vacuum using a simple mechanism.

[Means for solving problems]

The above object is achieved by twisting the base film held between the substrate supply roll and the substrate take-up roll to hold the base film in a so-called Möbius strip shape.

[Effect]

When a Möbius strip twist is applied once to the substrate film at the center between the substrate holding parts in the paper deposition device, both sides of the base film face the evaporation source before and after the twist is applied. If medium formation is performed while feeding the substrate film in this state, the medium can be formed on both sides of the substrate film in a four-vacuum environment.

〔Example〕

The present invention will be explained below with reference to Examples.

FIG. 1 shows a basic configuration diagram of an apparatus for realizing the method of manufacturing a magnetic recording medium according to the present invention.

In this embodiment, a heat-resistant polyimide film is used as the substrate film. The film properties are as follows. Heat resistance temperature is approximately 2500, temperature expansion coefficient is x, 5xto
-5/r, temperature expansion coefficient is 1.0XIO-5/%H1
Surface roughness is 0-01 II m p for both front and back surfaces.
9% Young's modulus is 800 Kf/m".

The film thickness is 50 μm.

The medium was produced by vacuum evaporation. The degree of vacuum during deposition is I
A magnetic recording medium was fabricated using a vacuum evaporation apparatus having the configuration shown in FIG. 1, although X 10-' Torr and substrate temperature were kept constant at 150C. Since the heat-resistant polyimide film used in this example generates gas such as H20 at high temperatures, the film was heated and degassed before starting vapor deposition. The film is heated by the heat transfer effect from a substrate supply roll 1 and a substrate take-up roll 2 each having a built-in heater.

The base film 3 is wound around a substrate supply roll 1 and a substrate take-up roll 2, and is wound up by the take-up roll 2 at a constant speed while applying a constant tension.

Furthermore, the base film 3 is supplied with a supply roll 1 and a take-up roll 2.
The substrate passes through a substrate guide roll 4 between the substrates. At this time, part of the substrate guide roll 4 is attached at a position intersecting with the base film 3. Therefore, the base film 3 sent from the supply roll 1 passes through this substrate guide roll 4, so that the front and back sides are reversed.
It will be wound up on a take-up roll 2.

The base film 3 that has completed the degassing process is transferred to the supply roll 1
Powered by.

Next, the Co-Cr alloy is evaporated from the evaporation source 5 in the same vacuum to form a ferromagnetic metal film of Co-21wt-Cr with a film thickness of 3500.
Then, Si is evaporated to form a protective layer with a thickness of 200 mm.

Furthermore, the base film 3 passes through the substrate Gaitronil 4. After passing through the substrate guide roll 4, the front and back sides of the film 3 are reversed, so that the surface on which the film 3 is not deposited becomes the evaporation source 5.
and 6.

Next, after forming a magnetic recording layer and a protective layer in the same procedure as above, the medium is wound around the winding roll 2, and the vapor deposition operation is completed.

A plurality of substrate guide rolls 4 for reversing the film surface may be provided.

〔Effect of the invention〕

As explained above, according to the present invention, medium forming layers can be formed on both sides of a base film in the same vacuum. Therefore, compared to conventional media manufacturing methods, work efficiency can be more than doubled.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the configuration of a manufacturing apparatus for carrying out the method of manufacturing a magnetic recording medium according to the present invention. 1... Board supply roll, 2... Board winding roll, 3
...Base film, 4...Substrate guide roll, 5
... Steaming z 1 ω Sho 2 k to ay, o-+ to 3 - again film 4 group Jkfi"h' roll S difference Yan'an, (Co-C+) b tA source (S9)

Claims (1)

[Claims] 1. In a method for manufacturing a magnetic recording medium that uses a ferromagnetic metal thin film as a magnetic recording film and has a flexible substrate, by twisting the substrate, the front and back surfaces of the substrate are faced to the evaporation source at the same time, and the same atmosphere is created. A method for manufacturing a magnetic recording medium, characterized in that magnetic recording media are simultaneously formed on both sides of a substrate.