JPS6074121A - Manufacturing device of high density magnetic recording medium - Google Patents

Abstract

PURPOSE:To execute a vertical orientation and a fixation of an axis of easy magnetization of a particle of a coated film to which a magnetic paint has been applied, without receiving a spatial restriction, by using a superconductive coil for generating a magnetic field. CONSTITUTION:A device consists of a pair of upper and lower superconductive coils 1, 2, a reinforcing material such as a support 3, etc., and a cryostat 4 for keeping the superconductive coil at a cryogenic temperature. An undried magnetic coated film 3 is led into a vertical magnetic field generated by the superconductive coils 1, 2, and first of all, magnetic particles in the coating film are oriented vertically, and subsequently, in order to fixing an oriented state, a hot air 4 is fed through a hollow part of the upper coil. As a result, the coated film becomes to have a high viscosity, and even if a diamagnetic field is generated, the oriented state of the particles does not fall into disorder. A vertical magnetic field space made by said method can be widened enough, and also a guide roll 5 or an air blow-out port for air floatation can be provided optionally in the vertical magnetic field space.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a high-density recording medium and a method and apparatus for manufacturing a magnetic recording IL body having excellent high-density recording characteristics.

[Technical background of the invention and its problems]

A magnetic recording medium includes a support such as a polyester film,
It consists of a magnetic layer provided thereon. -t- for the purpose of improving the magnetic properties of the magnetic layer in a certain % direction,
Following application of the magnetic paint onto the support, magnetic field orientation treatment of the magnetic particles has been used. In conventional magnetic recording media, after a magnetic paint in which acicular magnetic particles are dispersed in a binder is coated on a substrate + IC, the paint film is undried and the magnetic particles can rotate in a specific direction within the coating surface. For example, orientation processing is performed by applying a magnetic field in the longitudinal direction of the tape.

By orienting the magnetic particles in this manner, it has been possible to increase the squareness ratio of the magnetic recording medium and improve its sensitivity.

However, in recent years, 4i has increased to 19 years in high-density recording.
1! As a result of research, it was found that magnetic recording/1.1. There is a limit to the improvement of density, and in order to increase the density, it is necessary to use a magnetic recording medium in which the axis of easy magnetization of the magnetic particles is oriented perpendicular to the medium surface, and to use residual magnetization in the direction perpendicular to the medium surface. It became clear that it was necessary to use perpendicular 1α magnetic recording, that is, perpendicular 1α magnetic recording.As a magnetic recording medium with perpendicular anisotropy used for such recording, C0-( An Hr alloy film is known, but a film in which magnetic particles are coated with magnetic particles and oriented vertically is considered to be more practical, and research and development thereof is progressing. In order to apply dispersed magnetic paint and orient it vertically, it is necessary not only to place the paint film in a undried state where the magnetic particles can rotate in a magnetic field perpendicular to the paint film surface to orient the particles, but also to orient the particles. Furthermore, it is necessary to fix the perpendicular 1G orientation state by increasing the viscosity of the coating film and making it impossible for the magnetic particles to rotate, such as by performing a dry process in a magnetic field. 57-58245 and Japanese Patent Application Laid-Open No. 57-58246.Therefore, a vertical a-field generating device used for manufacturing long magnetic recording media requires a part used for orientation and a part (dried in a magnetic field). As a magnetic field generating device used for such particle orientation, electromagnets or permanent magnets of this size have been proposed.

However, when electromagnets or permanent magnets are used to orient particles in coating 11, the following problems become apparent: VC/1: First of all, in electromagnets and permanent magnets (N pole and S
For the pole, we must use the stable field that occurs in a very narrow gap. This sky 1; Kl-f, in which the 41i body is rarely 11fl and oriented without touching the magnetic poles, increasing the length of the magnet to an excessively large extent is regression, so the conditions for orientation and fixing the orientation state. 7 (If a weak state is not obtained, or 1. In order to satisfy this issue,
There were problems such as having to limit the coating speed. The magnetic field gap of these magnets cannot be widened more than several 07 I in order to ensure a safe magnetic field of K H' for the purpose of orientation, 2 KO/ or more, preferably 4 KOt or more.

The second problem relates to the drying process for fixing the orientation state in a magnetic field. It has been found that it is difficult to provide sufficient means for fixing the coating film in the narrow gap between the magnetic poles.

[Purpose of the invention]

An object of the present invention is to provide a magnetic recording medium manufacturing apparatus that improves the problems of the conventional method. By using the present invention, it is possible to vertically align and fix the axis of easy magnetization of the particles of the coating film coated with magnetic paint without being subject to spatial constraints, and it is possible to create a perpendicular magnetic recording medium that is well oriented in the vertical direction. f3: Can be manufactured.

[Summary of the invention]

That is, the present invention applies a full perpendicular magnetic field to a magnetic coating film containing magnetic particles (2) coated on a substrate, so that the axis of easy magnetization of the magnetic particles is mainly perpendicular to the coating surface. A method of manufacturing a high-density magnetic recording medium, which is oriented in the direction of the magnetic field, is characterized in that a superconducting coil is used to generate a magnetic field.

Now, the superconducting coils used in the present invention are 1&I+
&lH,'2! ! 〒6. r/, -IJ'! J-Nanumi→
Lee) Muaa4W-h=-Large-f:ahh+/'-Although it is likely that K1 cannot be generated by a normal electromagnet, it can be used to generate a high magnetic field, so magnets for magnetic levitation trains can be used for nuclear fusion plasma. Research is currently underway to find out how to apply it to confinement magnets, etc. By generating a magnetic field using a super'+lt conductive coil, the present inventors
The strength of the magnetic field is comparable to that generated by a normal electromagnet, but it spreads over a room temperature space much wider than that of a normal electromagnet.
We developed a superconducting coil capable of generating an It was also found that it was easy to pass the coated body through. The magnetic field space is wide, and the superconducting coil is an air-core coil. Air blowing for drying, etc.:
It is now possible to blow air to make the applied body sound air float and run stably.

〔Effect of the invention〕

In this way, the superconducting coil of the device developed in the present invention can obtain a magnetic field space of sufficient size necessary for vertical orientation and fixation of coating particles, which could not be obtained with ordinary electromagnets or permanent magnets. Since it is easy to blow air from the outside, it is applied to the production of perpendicular anisotropic media for high-density magnetic recording (7) As a result of the drastic process change, the characteristics of the media and the durability of the media are improved. It became possible to do so.

[Embodiment 1] The method for vertically orienting magnetic particles in a coating film according to the present invention will be explained using a specific example. FIG. 1 is a diagram showing an example of an orientation apparatus based on the present invention. The device consists of a pair of upper and lower superconducting coils f.
It consists of reinforcing materials such as il, +2+ and supporting columns (3), and a solid fly tact (4) that keeps the conducting coil at an extremely low temperature. FIG. 2 is a diagram showing an example of the situation when performing orientation using this orientation device, and shows a pair of upper and lower its'(, tt, conductive coils (
I) Introducing the undried magnetic coating film (3) into the vertical magnetic field generated by (2), vertically aligning the magnetic particles in the coating film, and then fixing the orientation state by - )−+;
Hot air (4) is sent through the hollow part of the +1 coil. As a result, the coating film that passed through the orientation device had a very high viscosity.
3. Even when the external perpendicular magnetic field becomes zero and the demagnetizing field is suppressed, the orientation state of the particles is not disturbed. -1,-'l/ This vertical 1 is made by a pair of superconducting coils, and the different space can be made sufficiently wide, and since the fill is 91° inside, the magnetic coating support l=,3. Guide roll for (5
) An air outlet for air floating can be arbitrarily provided within the vertical magnetic field space.

In the present invention, 1j (4 conductive coils (1'□i example of bamboo 01≦belt coil winding frame rC multifilament super Mj-j'L IF'A with required number of tickets) liquid helium]φ (After soaking in I and covering the entire tank with a completely insulated structure, its outer wall f: Cooling structure with liquid nitrogen and
, σ) Furthermore, the first side is covered with a heat insulating layer, and furthermore -r, (>', lsu〒heat (1°J) is provided on the outside.

Next, the present invention will be explained by way of implementation.

Example 1 First, a magnetic paint having the following composition 7111 was used; j11
100 parts of barium fluorite conomyltotitano-substituted product prepared by ', l (average particle size O] μm, specific surface area 2 (hr?/F/, H
o=9000°) Vinyl chloride vinyl acetate copolymer 10
Part polyurethane resin 10 parts Lecithin 2 parts Methyl ethyl ketone 70 parts Cyclohexanone 70 parts Toluene 70 parts The above composition was cross-dispersed and made into a paint, which was applied to a polyethylene terephthalate film using a coater head, and coated with a superconducting coil at 200o++. , 1
It passes through a vertical magnetic field space of 0KOe, and the first half of it is 50C.
Orientation is carried out at rn, and hot air is sent at the rear half 150 cm to form a coating film 1'+ in the magnetic field. , i degree increase was performed to fix the orientation state, and then passed through a drying zone. After drying, the surface of the coating film was smoothed using a super calender.

In this case, when the running speed of the coating film was changed, we investigated the change in the squareness ratio (R) of the magnetic hysteresis loop measured in the direction perpendicular to the film surface (one with demagnetizing field correction). . As a result, f: Figure 3 V (: not shown. As is clear from this figure, the value on R is maintained even if the degree of Ai is increased to 7r row j of the coating film by ]-00m/"y). I understand that.

(Comparative example) The same paint as in the practical example was applied onto a polyethylene terephthalate film, and this was passed through a vertical magnetic field space of 40c1n in length and 10KOc by an ordinary fK electromagnet with a chisel, and the orientation was achieved in the front half 20-. Go, second half 20trn
7'451.1<x in the magnetic field by blowing air from the side.
i'1'i I([i was raised to fix the orientation state.Furthermore, the same treatment as in the implementation V/lJ and d(11 constant) were performed and the results are shown in Figure 511, 4.From the figure, it is clear that the coating film It can be seen that as the traveling speed increases, 1 decreases, and the maximum value of R is smaller than that of the actual pain example of the present invention.

As shown in the examples above, 1. ↑ (Using the umbrella coil as the magnetic field for vertical alignment of the magnetic particles in the magnetic coating film makes it possible to utilize a wide magnetic field space, which is advantageous for tape running and enables high-speed alignment processing. River 1i-4)su, j
It was found that a high degree of orientation can be obtained.In this experiment, we have described the use of cobalt titanium substituted barium 1 fullite as the magnetic powder, but other substituted barium fluorite, Furthermore, rFe 203
, Fe 304 , these intermediate iron oxides, C6 coatings, these oxides containing slag, F, Co, Ni and alloys thereof, alloys of these with B, P, etc. when using magnetic powders, etc. It was also confirmed that the self-alignment method described above can be used in the same way. The superconducting coil shown above is a symmetrical pair of upper and lower coils, but depending on the circumstances of use, the upper and lower shapes may be different.
They may be of different sizes, or in extreme cases, only one side may be used.

Power consumption is a big problem when using ordinary electromagnets, but when using superconducting magnets,
-1, since it is used in a state where the air resistance is zero, the force required to pass current through the coil is almost zero, and even if the power consumption of the device that cools the coil is combined, the electric power and power are almost zero. It can be said that the practical value of the present invention is that it consumes less energy and saves energy.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of the outline of a superelectric double magnet according to the present invention. Figure 2 is a cross-sectional view showing the state in which the perpendicular orientation of magnetic particles in a coating film is controlled using an ordering device according to the present invention, and Figure 31-1 shows the results of an example according to the present invention. Figure 4 is an explanatory diagram showing the result of a comparative example.
Coating film (5)...Guide roll Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) Applying a magnetic field perpendicular to one surface of a magnetic coating film containing paint containing magnetic particles on a substrate orients the axis of easy magnetization of the magnetic particles in a direction perpendicular to the coating surface. An apparatus for manufacturing a high-density IW magnetic recording medium, characterized in that a superconducting coil is used to generate a perpendicular magnetic field for recording and alignment. (2) A patent characterized in that the perpendicular magnetic field generating device using the superconducting coil has a coating film running mechanism for running the magnetic layer i1% in a magnetic field, and a processing mechanism for fixing the orientation state of the magnetic layer film. High density 1 according to claim 1
&Magnetic recording media manufacturing equipment.