JPS63104220A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To form the titled medium having excellent preservable stability by preserving a coiled and vapor deposited product formed by providing a magnetic metal and thin alloy film by a coiling vapor deposition method on a flexible substrate under the conditions under which gaseous flow contg. an oxidizing gas is generated in gasp while the vapor deposited product is coiled. CONSTITUTION:The substrate 17 on which the thin film is formed is wound on a hollow winding core 16. While the coiled and vapor deposited product is held sealed by hermetic seals 18, the inside thereof is evacuated to a vacuum by a vacuum pump 20 in order to generate the gaseous flow in the gaps 21 between the wound products. The gaseous flow is then generated in the gaps 21. Air is satisfactory as the atmosphere to generate such gaseous flow; gaseous NH3, NO2 and H2S are also usable. The stabler thin film is obtd. by bringing the thin metallic film which is still active right after the completion of the coiling and vapor deposition into reaction. The time for exposing the product to such gaseous flow is preferably >=12hr.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a magnetic recording medium, and more particularly to a method for manufacturing a metal thin film type magnetic recording medium having excellent weather resistance and storage stability.

[Conventional technology]

As magnetic recording media, so-called "coating type" magnetic recording media, in which a powdered magnetic material is coated on a non-magnetic substrate together with an organic binder and dried, have been widely used. However, in recent years, the demand for high-density magnetic recording has been met by so-called "metal thin film" magnetic recording media that have a large electrophase magnetic flux. Research and development is being carried out on perpendicular magnetization tapes, disks, etc. using vapor-deposited tapes, sputtering or vapor deposition of Co--Cr alloys.

However, such magnetic metal thin films generally have poor weather resistance. For example, there is a phenomenon in which the total amount of magnetic flux decreases by 104 or more when left under high temperature conditions. There is also the problem that rust that is visible to the naked eye occurs due to the repeated process of dew condensation and drying on paper. Decrease in the amount of magnetic flux and occurrence of rust 1! - Collectively referred to as weather resistance.

Various means have been proposed for improving the weather resistance of this metal thin film type magnetic recording medium, but most of them cannot be said to be sufficiently effective. -Also, there are problems such as requiring large-scale equipment and poor productivity, and there has been a desire for a simpler and more effective improvement in weather resistance.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and includes weather resistance,
The present invention provides a method for manufacturing a metal thin film magnetic recording medium with improved storage stability.

[Structure of the invention]

The present invention is a method of storing a rolled-evaporated product in which a thin film of magnetic metal or alloy is provided on a flexible substrate by a winding-evaporation method under conditions that generate an air flow containing an oxidizing gas in the gap between the wound parts. The present invention relates to a method of manufacturing a magnetic recording medium, characterized in that:

The flexible substrate of the present invention is mainly made of polyethylene terephthalate, polyimide, polyamide, polyvinyl chloride,
The substrate is made of plastic such as cellulose triacetate, polycarbonate, polyethylene naphthalate, etc.

An example of a winding vapor deposition apparatus is shown in FIG. This is a vapor deposition apparatus having a -chamber configuration, in which the flexible substrate 7 is sent out from a delivery roll t, moves along a cooling drum, and is taken up by a take-up roll/! It is wound up. The lower chamber 1 is a deposition chamber, and the vapor flow from the crucible IO is deposited on the substrate to form a magnetic thin film. What is shown in FIG. 1 is a method of forming a magnetic film by so-called oblique deposition, using a mask/? The incident steam flow is partly and completely regulated. It is also possible to use a method such as controlling the magnetic properties by introducing an oxidizing gas or the like through the gas inlets //, /, etc.

What is shown in FIG. 1 is a semi-continuous type take-up vapor deposition apparatus, in which when the thin film has been formed on the substrate fed from the feed rolls, the take-up roll l is adjusted according to the length of the substrate. A vapor-deposited product can be obtained.

One means for producing airflow sound in the gaps between the windings i of the rolled vapor-deposited product of the present invention will be explained with reference to FIG.

What is shown in Figure 2 (A) is a rolled vapor-deposited product, typically a substrate 1 on which a thin film is formed around a hollow core/B.
7 is rolled up. In Figure 1 (B), is there airflow in the air gap between the coils? One way to create gold is shown schematically, but it is an airtight seal! An air current is generated in the gap J/ by evacuating the rolled vapor-deposited product with a vacuum pump 0 while sealing it. In general, especially when a metal thin film is provided on a plastic substrate, and especially when the substrate is thin, the air gap 2/
The space is extremely narrow, and as shown in Figure 2, it is necessary to create some kind of airflow. Here, in FIG. 1 (B), the atmosphere may be air, or it may be a gas with a higher oxygen concentration to further increase the effect of the present invention.
Furthermore, more reactive gases such as ozone can also be used. Furthermore, it is possible to control the characteristics by combining the thin film material and the gas component of the airflow, and it is possible to
3 gas, NO2 gas, H2S gas, etc. can also be used. That is, the present invention can be considered as a simple means for reacting the still active metal thin film immediately after the completion of the winding vapor deposition to form a more stable thin film. The time for exposure to the air current varies depending on the film width, etc., but is preferably 72 hours or more.

Further explanation will be given below based on examples.

[Example, comparative example]

Steam 7i1 shown in Figure 7! Use the location! A magnetic thin film of CosoN i 20 (atom %) was deposited on a μm-thick polyethylene terephthalate substrate by an oblique deposition method. The film width is 300 mm, and the silver zoooo
A substrate of m was used. Conveyance speed is 30m7 minutes, incident angle θml, = J j ', thin thickness oo.

The vapor deposition was carried out while introducing an equal amount of 02 gas into the vapor deposition chamber 3 so that the degree of vacuum in the vapor deposition chamber 3 was 3.0×10' Torr. Under these same conditions, a roll-deposited product was obtained. Seven of these were left at room temperature and humidity for a week (these are Sample A). The other seven tubes were set in the apparatus shown in Figure 1 (B), kept in vacuum for a week using a rotary pump θ, and exposed to airflow (this is Sample B).

After that, from this co-sample, samples of IO\s x 7t% were cut out at intervals of 7000 m (referred to as A/~A-Otsu and Otsu7-Otsu2).

The lower the number, the more the sample is cut from the inside of the roll. ). Above 72 samples ft00C9o4R
The total amount of magnetic flux φ before and after leaving it in an atmosphere of H for a week
mCMXZα) (fi value is 俤) It can be judged that the smaller the value of this change rate -Δφm/φrn, the better the weather resistance is. Sample O shows almost the same low values for all of Otsu/~Otsu Otsu, whereas in Sample A, only the outermost A and B of the rolled vapor-deposited product are low, and the weather resistance is low in the middle of the roll. It turns out that it is defective.

〔Effect of the invention〕

As described above, according to the method of the present invention, it is possible to easily and uniformly produce a metal thin film type magnetic recording medium with improved weather resistance.

[Brief explanation of the drawing]

FIG. 1 shows a winding vapor deposition apparatus. FIG. 2(A) shows the external appearance of the rolled vapor-deposited product, and FIG. 2(B) shows the device for generating airflow. /...Vacuum tank B...Feeding roller...Cooling drum//, 12...Gas, etc. inlet/j...Take-up roller /l...Hollow core /I? ... Airtight seal 20 ... Vacuum pump patent applicant Fuji Photo Filno Co., Ltd. Figure 2

Claims (1)

[Claims] A rolled vapor-deposited product, in which a magnetic metal or alloy thin film is provided on a flexible substrate by a rolled-up vapor deposition method, is stored under conditions that generate an air flow containing oxidizing gas in the gap between the rolled vapor-deposited products. A method of manufacturing a magnetic recording medium, characterized in that: