JPS58200422A - Magnetic recording and reproducing plate - Google Patents

Abstract

PURPOSE:To obtain a magnetic disk, etc. which is suited especially to the high- density recording with excellent strength, by bonding two substrates obtained by vapor depositing a ferromagnetic and metallic thin film on a single side of a comparatively thin polymer substrate to a comparatively thick polymer forming product substrate of the same material as said two substrates at the side opposite to a magnetic film. CONSTITUTION:A ferromagnetic and metallic thin film 4 is formed by a vacuum vapor deposition on a single side of a comparatively thin polymer substrate 3. Two sheets of such substrate 3 are bonded on both sides of a forming product substrate 5 having a comparatively large thickness and the same material as the substrate 3 by means of an adhesive 6 and with the film 4 set outside. This bonded substrate is consecutively blanked into a desired shape including a circle, an oblong, etc. in order to obtain a floppy disk, a magnetic card, etc. The substrate 3 is adhered close to a cooling drum owing to a small thickness of the substrate 3 when the film 4 is vapor deposited, and therefore the vapor deposition is carried out evenly with good smoothness. Furthermore the mechanical strength is increased with junction of a substrate 5. Thus it is possible to obtain simply and with a low cost a high-density recording/reproducing plate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording/reproducing plate having a ferromagnetic metal thin film, and particularly to easily provide a magnetic recording/reproducing plate intended for high-density recording.

Generally, a magnetic recording/reproducing plate has a structure in which a magnetic medium 2 in which ferromagnetic powder is dispersed in an organic polymer binder is coated on the surface of a polymer molded substrate 1, as shown in FIG. However, the filling rate of magnetic powder was limited and the coating thickness was too thick, making it unsuitable for high-density recording. Furthermore, because the surface electrical resistance is relatively high (1 x 107 or more), it is easily charged with static electricity and easily attracts dust, etc. This can cause errors if it is not used for floppy disks, etc. ing. As a method for solving this drawback, a method has been proposed in which a ferromagnetic metal thin film is continuously formed directly on a substrate by vacuum evaporation or the like. In other words, in the case of a ferromagnetic metal thin film, since it is a 100-inch ferromagnetic material, the film thickness can be made thinner, high-density recording is possible, and the surface electrical resistance is very low compared to coating-type ones. There were also fewer errors caused by static electricity build-up and dirt.

However, there are some problems with the current method of manufacturing magnetic recording/reproducing plates using the vacuum evaporation method.

That is, if an attempt is made to directly form a metal thin film on a plastic film H of several tens of microns by vacuum deposition, the film will simply be succumbed to the radiant heat of the molten metal, so it cannot be formed continuously. Generally, in order to evaporate continuously on a plastic film, it is necessary to sufficiently cool the surface of the film, and to do this, the film must be tightly attached to a cooling can to improve heat conduction, and the film itself must be tightly cooled. It is necessary to improve heat conduction. However, since the thermal conductivity of the film itself is constant, there is a limit to the thickness of the film.Also, the adhesion of the film to the cooling can is affected by the surface properties of the film, static electricity, and secondary electrons in the case of electron beam heating. to be influenced. Therefore, if the surface properties of the film are poor, if the back side of the film (cooling can side) is not easily charged with static electricity that has already been deposited, and if a method such as resistance heating is used instead of electron beam heating,
If secondary electrons are not generated, the adhesion of the film to the cooling can becomes extremely poor.

In the inventor's experience, using a polyethylene terephthalate film, the surface roughness of the film was 0 in terms of center line average roughness.
．． 01μ, electron beam heating, it is possible to evaporate films with a thickness of about 20μ or less without vapor deposition on the back side of the film, but if the back side is vapor-deposited and the thickness is about 20μ, the mechanical strength is weak for use in floppy disks etc. It is incompetent.

In addition, thicker films are compared to thinner films -CK
1 (11) has poor roughness and is not suitable for high-density recording, and has the drawback of low productivity and high contrast because the length per recording is unknown.

Below 1-. Thick plastic film by vacuum deposition, such as 1. There are many drawbacks to the method of directly forming metal thin films on
Practical is impossible.

The present invention eliminates the above-mentioned drawbacks and enables high-density recording to 11
It is possible to provide high-performance magnetic recording/reproducing plates at low cost and in large quantities.

In the present invention, a sheet in which a ferromagnetic metal thin film is vacuum-deposited on one side of a relatively thin polymer molded substrate is applied to at least one side of a relatively thick polymer molded substrate made of the same material as the relatively thin polymer molded substrate. A magnetic recording and reproducing plate characterized in that its substrate sides are bonded together via an adhesive layer, and the adhesive layer is made of the same material as the polymer molded substrates on both sides of the magnetic recording and reproducing plate. It is a board.

Next, one embodiment of the present invention will be described using the drawings.

FIG. 2 shows a schematic cross-sectional view of a magnetic recording/reproducing plate, in which a polymer molded substrate 30 made of relatively thin polyethylene terephthalate or the like is coated with C on one side.

-A ferromagnetic metal thin film 4 made of a Ni alloy was formed by vacuum evaporation and bonded to both sides of a relatively thick polymer molded substrate 6 made of polyethylene terephthalate or the like with an adhesive layer 6 interposed therebetween. It is something. Appropriately, the relatively thin polymer molded substrate 3 has a thickness of 2 to 20 μm, the relatively thick polymer molded substrate 5 has a thickness of 20 to 80 μm, and the adhesive layer 6 has a thickness of 0.5 to 6 μm. The thickness of the ferromagnetic metal thin film 4 is 0.05-0.5μ. The substrate 3 and the substrate 6 are made of exactly the same material, and the adhesive layer 6 is made of the same material as the substrate 3 and the substrate 5 in the first embodiment, and is made of a different material from the substrates 3 and 6 in the second embodiment, but the temperature The expansion coefficient and the temperature expansion coefficient are the substrate 3,
An epoxy resin that is relatively similar to No. 6 was used. In either case, the influence of temperature and humidity is not expected at all, and the deformation it v
Figure 3 is a schematic cross-sectional view of the vacuum steaming apparatus used in the present invention, in which the polymer molded substrate 3 is passed from the unwinding shaft 7 through the cooling can 8 in a vacuum chamber (not shown). Take-up 11
ql + 9, 4 Daisui company winding iL. A ferromagnetic evaporation source 10) made of a CoNi alloy is placed at a position facing the cooling can 8 with the substrate 3 in between, and the electron beam 1
1. Evaporation source 1o heated to required temperature
The evaporation 12 generated by the evaporation passes through the gap between the mask 13 installed between the substrate 3 and the evaporation source 1o, reaches the surface of the 1-1 substrate 30, and forms a thin film there. Although the bonding of the comparatively thin substrate 3 and the comparatively thick substrate &5 is not particularly shown in the figure,
This is possible by generally known wet or dry continuous simulating treatment.

As described above, the present invention is to continuously provide large quantities of magnetic recording/reproducing plates capable of high-density recording at low cost. That is, a magnetic recording medium suitable for high-density liver recording is created by continuously forming a ferromagnetic metal thin film on one side of a polymer molded substrate that is relatively thin and has good surface properties by vacuum deposition. The substrate side is continuously bonded to at least one side of a relatively thick polymer molded substrate made of the same material as the polymer molded substrate through an adhesive layer, and this is continuously punched out to form a predetermined shape (length). It is formed into a 2-circular shape, etc.). By kneading, magnetic recording and reproducing plates for high-density recording that satisfy mechanical properties and weather resistance can be provided in large quantities at low cost, and the industrial effects thereof are very large.

Note that the polymer molded substrate used in the present invention is not limited to polyethylene terephthalate, and even if the substrates 3 and 6 are not made of exactly the same material, they may be relatively similar in temperature expansion coefficient, humidity expansion coefficient, etc. Furthermore, even if the adhesive layer is not made of exactly the same material as the substrates 3 and 6, it may be made of a different material as long as the temperature expansion coefficient, humidity expansion coefficient, etc. are relatively similar. In addition, the mechanical strength of the polymer molded substrate is improved by omitting the relatively thick polymer molded substrate, and by vacuum-depositing a ferromagnetic metal on one side, the two substrate sides are attached via an adhesive layer. They can be combined.

The shape of the magnetic recording/reproducing plate of the present invention is not particularly limited.
It can be made by punching out any shape, such as a circular shape such as a Thoropy disk, or a rectangular shape such as a magnetic card, from a long sheet of plastic material.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a conventional magnetic recording/reproducing plate, FIG. 2 is a schematic cross-sectional view of a magnetic recording/reproducing plate according to an embodiment of the present invention, and FIG.
The figure is a diagram showing a schematic structure of a vacuum evaporation apparatus used in the present invention. 3.6...Polymer molded substrate, 4...
Ferromagnetic metal thin film, 6...Adhesive layer.

Claims (1)

[Claims] (1) A ferromagnetic metal thin film is formed by vacuum deposition on one side of a relatively thin polymer molded substrate, and the other side of this polymer molded substrate is formed with a relatively thick polymer molded of the same material as the substrate. A magnetic recording/reproducing plate characterized by being bonded to a physical substrate via an adhesive layer. (The magnetic recording/reproducing plate according to claim 1, wherein the two adhesive layers are made of the same material as the polymer molded substrates on both sides thereof.