JPH057765B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) This invention relates to a magnetic recording medium manufacturing apparatus. (Prior art) In a magnetic recording medium manufacturing apparatus, a magnetic paint is applied to a substrate, and it is subjected to a magnetic field orientation treatment.
Devices that cure materials by irradiating them with electron beams are already well known. In that case, it is also known that if the magnetic paint is cured by irradiating electron beams during magnetic field orientation, a good magnetic paint film with good orientation can be obtained (for example, see Japanese Patent Application Laid-Open No. 129700/1983). ) Figure 6 shows a conventional device for this purpose.
2 is a substrate such as a film, 2 is an orientation magnet, and 3 is an electron beam irradiation device. The magnetic particles in the magnetic paint applied to the substrate 1 by the application unit 4 are oriented by the magnetic field formed by the orientation magnet 2. At the same time, an electron beam from an electron beam irradiation device 3 is irradiated through an irradiation window installed in the orientation magnet 2, and the magnetic paint is cured. After this, drying oven 5
The solvent is dried by 6 and 7 are an unwinding roll and a take-up roll. According to this, even if curing can be performed by electron beam irradiation during magnetic field orientation, the coating surface will become rough because the curing is performed in the coexistence of a solvent. To avoid this, it is possible to make the magnetic paint highly viscous, but doing so requires a long time for application, inhibits the speeding up of the orientation and curing process, and causes poor orientation. There are disadvantages such as: Therefore, it is desirable for the magnetic paint to have as low a viscosity as possible. (Problems to be Solved by the Invention) This invention uses a magnetic coating film with less surface roughness and excellent orientation when manufacturing magnetic recording media.
The purpose is to enable manufacturing even when using low viscosity magnetic paint. (Means for Solving the Problems) The present invention applies a magnetic paint to a substrate and then irradiates it with an electron beam at the same time as magnetic field orientation in an undried state. The magnetic coating surface of the substrate is conveyed with the surface of the rotating drum in contact with the surface of the rotating drum, and during the conveyance process, the magnetic coating material is cured by electron beam irradiation during magnetic field orientation. It is characterized by (Example) An example of the present invention will be described with reference to FIG.
Note that parts given the same reference numerals as in FIG. 6 indicate the same or corresponding parts. Magnetic paint 9 in container 8
is applied to the surface of the substrate 1 by a roll 10. Since the coating is applied to the lower surface of the substrate 1 here, coating with a roll coater is suitable. According to this invention, a rotating drum 10 whose surface is mirror-finished is provided inside the orientation magnet 2. An example of the orientation magnet 2 suitable for this purpose will be explained with reference to the drawings. Here, one magnetic pole 12 having a fan-shaped head 11, the other magnetic pole 13 having a fan-shaped shape concentric with the head 11, and a yoke 14 connecting both magnetic poles 12 and 13.
A magnetizing coil 15 wound around this yoke 14 constitutes an orientation magnet. The rotating drum 10 is arranged so as to surround the magnetic pole 12, and is rotatable by a motor 16. An irradiation window 17 is formed in the magnetic pole 13, and the electron beam from the electron beam irradiation device 3 is irradiated toward the surface of the rotating drum 10 through this irradiation window 17. 18 is a magnetic shield. The electron beam taken out into the air is designed to prevent it from colliding with the magnetic pole 13, but this magnetic shield 18 is also provided to reduce the leakage magnetic flux in the irradiation window 17 and prevent the electron beam from colliding with the magnetic pole 13. Its path is curved to prevent it from colliding with the magnetic pole. In the above configuration, the base 1 whose surface is coated with magnetic paint passes through the magnetic field between the magnetic poles 12 and 13 while being in contact with the surface of the rotating drum 10. During the passing process, the electron beam from the electron beam irradiation device 3 is irradiated. Therefore, the magnetic paint becomes hardened during magnetic field orientation. In this respect, there is no particular difference from the conventional structure, but as described above, in these processing steps, the surface of the base 1 coated with magnetic paint is attached to the mirror-finished surface of the rotating drum 10. As a result, a mirror surface is transferred to the surface of the substrate 1, thereby making the surface of the substrate 1 smooth and glossy. In this case, if the substrate is irradiated with an electron beam during magnetic field orientation to harden the magnetic paint, and then a rotating drum is used to perform a mirror finish, the magnetic paint has already hardened by the time the mirror finish is applied. Because of this, even if the substrate is attached to the rotating drum, it is no longer possible to achieve a mirror finish. However, if the substrate is attached to the rotating drum in the process of irradiating the electron beam during magnetic field orientation as described above,
Since this is before the magnetic paint has hardened, it is possible to achieve the desired mirror finish. Moreover, as shown in the figure, one magnetic pole 12 of the orientation magnet 2 is placed inside the rotating drum 10, and the other magnetic pole 13
is placed outside the rotating drum 10, and the other magnetic pole 1
3, an irradiation window 17 for irradiating the surface of the rotating drum 10 with an electron beam from an electron beam irradiation device.
As a result, electron beams can be irradiated during magnetic field orientation, and a mirror finish can be achieved by the rotating drum 10 during the irradiation process. Note that when it is necessary to cool the rotating drum 10, a water cooling pipe may be appropriately installed inside the drum.
Although an electromagnet is used in the figure to generate the orientation magnetic field, it may also be a permanent magnet. Although the orientation magnetic field in the figure is a vertical magnetic field, the present invention is also applicable to a horizontal orientation magnetic field. Although the illustrated configuration has a yoke 14 installed on one side of the magnetic pole 12, the yoke 14 may be installed on both sides as shown in FIG. 5 instead.
In that case, in order to drive the rotary drum 10, a rolling drum 20 may be prepared and rotated by the motor 16. (Experiment Example) The composition of the magnetic paint used in the experiment is as follows. Barium ferrite 100 parts Phosphate ester 7 parts Vinyl chloride, vinyl acetate, vinyl alcohol copolymer 10 parts Urethane acrylate oligomer 9 parts Triallylisocyanurate 2 parts Trismercaptylpropyl isocyanurate
4 parts Toluene 80 parts Cyclohexane 80 parts The above components were kneaded in a ball mill for 50 hours to obtain a magnetic paint. The viscosity of this magnetic paint is 4000cps
It was hot. The electron beam absorption dose is 5 Mrad, the orientation magnetic field is 5KG, and the processing speed is 200m/min. The following table shows the results obtained under these test conditions. In this table, the squareness ratio indicates the ratio of the residual magnetic flux density to the saturation magnetic flux density of the vertical component of the coating film. The surface gloss was measured using a variable angle gloss meter at a measurement angle of 60 degrees. The surface roughness was measured using a stylus surface roughness meter at a cutoff value of 0.25.
The centerline average roughness according to JISB0601-1982 is shown. In the table, Sample 1 is manufactured using the apparatus shown in Figure 2, Sample 2 is manufactured using the apparatus shown in Figure 5, and Sample 3 is the one manufactured using the apparatus shown in Figure 5. For this purpose, the products manufactured by the apparatus shown in FIG. 6 are respectively meant.

[Table] As understood from the table above, samples 1 and 2
The squareness ratios of both samples are almost the same as those of sample 3, but better results than those of sample 3 are obtained in both surface gloss and surface roughness. (Effects of the Invention) As detailed above, according to the present invention, a magnetic coating film can be produced at high speed using a low-viscosity magnetic coating material, and, as in the past, electron beam irradiation is applied during magnetic field orientation. By curing the magnetic paint, the orientation of the magnetic paint film is improved, and during the magnetic field orientation and electron beam irradiation, in other words, before the magnetic paint is cured, the rotating drum for mirror finishing the substrate is used. Since it is attached to the surface, it is possible to produce a coating film with excellent surface smoothness and gloss on the substrate.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a partially enlarged front view, Fig. 3 is a partially sectional side view, and Fig. 4 is a perspective view of the main parts. , FIG. 5 is a partially sectional side view showing another embodiment of the present invention, and FIG. 6 is a front view showing a conventional example. DESCRIPTION OF SYMBOLS 1... Base body, 2... Orienting magnet, 3... Electron beam irradiation device, 10... Rotating drum, 12, 13... Magnetic pole.

Claims (1)

[Claims] 1. An alignment magnet for magnetic field alignment is arranged along the transport route of the substrate whose surface is coated with magnetic paint, and an electron beam is irradiated to harden the magnetic paint during magnetic field alignment by the alignment magnet. In a magnetic recording medium manufacturing apparatus in which a radiation irradiation device is arranged, one magnetic pole of the orientation magnet is arranged inside a rotating drum whose surface is mirror-finished;
By arranging the other magnetic pole outside the rotating drum, the rotating drum is placed within the alignment magnetic field of the alignment magnet, and the electron beam from the electron beam irradiation device is directed into the other magnetic pole by the rotating drum. An irradiation window is formed that irradiates toward the surface of the drum, and a magnetic shield is provided from the surface of the other magnetic pole on which the irradiation window is formed to the inner surface of the irradiation window, and the substrate is connected to the rotating drum. A magnetic recording medium manufacturing device that conveys a magnetic recording medium by attaching it to the surface.