JPS61211823A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To decrease substantially the electric resistance of a magnetic recording medium and to improve the electromagnetic conversion characteristic by carbonizing the surface of a substrate consisting of a high-polymer compd. to form a carbonized layer and forming a magnetic layer on the front or rear surface of the substrate having such carbonized layer. CONSTITUTION:The C-C bond on the surface of the substrate consisting of the high-polymer compd. is cut by high energy ions and carbonized, by which the amorphous carbon is formed and the carbonized layer is formed when ions are implanted to the surface of the substrate consisting of the high-polymer compd. in a vacuum atmosphere by using an ion implanting device. The magnetic layer is provided on the front or rear of such substrate. The electric resistance of the magnetic recording medium is substantially decreased when the magnetic layer is formed on the carbonized layer. The surface characteristic of the magnetic layer is thus improved and the electromagnetic conversion characteristic is satisfactorily improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnetic recording medium, and more particularly to a magnetic recording medium with low surface electrical resistance and excellent electromagnetic conversion characteristics, and a method for manufacturing the same.

[Conventional technology]

The magnetic layer of a magnetic recording medium is formed by applying a magnetic paint consisting of an oil-tight magnetic powder, a binder resin, a solvent, and other necessary components to a substrate such as a polyester film, and drying it. The magnetic layer formed in this way has a relatively high surface electrical resistance and is not easily charged, and may generate noise during discharging or may become contaminated with dust.
' Loss drop-out may increase, and in the case of magnetic tapes, sticking phenomena may occur during running.

Therefore, as a countermeasure, carbon blanks are included in the magnetic layer (Japanese Patent Publication No. 58-31654), or antistatic agents are included in the magnetic layer (Japanese Patent Publication No. 58-58).
No. 456), or an undercoat layer containing carbon blank is provided between the substrate and the magnetic layer (document unknown), or even a hack coat layer containing carbon black is provided on the back side of the substrate opposite to the magnetic layer side. To form a special public service 1987-1
9492) to reduce the surface electrical resistance of the magnetic layer.

[Problem that the invention attempts to solve]

Although these methods reduce the surface electrical resistance of the magnetic layer, they are not completely satisfactory.

[Means for solving problems]

This invention was made as a result of various inspections in view of the current situation. By carbonizing the surface of the substrate to form a carbonized layer and forming a magnetic layer on the front or back surface of the substrate having this carbonized layer, the electrical resistance of the magnetic recording medium can be sufficiently reduced and the electromagnetic conversion characteristics can be improved. This is a combination of two.

The present invention will be described below with reference to the drawings.

Figure 1 shows a schematic cross-sectional view of the ion implanter.
This ion implanter iJ includes an ion generation chamber 2 equipped with an ion source gas introduction system 11, an accelerator 3 that accelerates the ions generated in the ion generation chamber 2 and guides them in a predetermined direction, and The ions are separated according to the amount of Tr, and the necessary ions are taken out. He scans J. Lu in room 5, and ion? It consists of an injecting chamber (1) and an injecting chamber (6), in which ions are injected into the base 7 of the polyester film collar placed inside the injecting chamber (in a vacuum atmosphere), and the injecting chamber (7) is injected into the injecting chamber (1). The surface is carbonized. 8 is an exhaust system for evacuating the Him scanning chamber 5, and 9 is an exhaust line for evacuating the ion implantation chamber 6.

When ions are implanted into the surface of a substrate made of a polymer compound in a vacuum atmosphere using an ion implantation device, the C-C bonds on the surface of the substrate made of a polymer compound form high-energy ions. is cut and carbonized to produce amorphous carbon and form a carbonized layer. The carbonized layer made of amorphous carbon formed on the surface of the substrate made of this polymer compound has good electrical conductivity. As a result, the electrical resistance of the magnetic recording medium is sufficiently reduced, and noise generation due to charging and dross dropout 1-
This effectively suppresses the increase in the amount of carbon, stickiness during running does not occur, the surface properties of the magnetic layer are good, and the electromagnetic conversion characteristics are sufficiently improved. This effect is similarly exhibited when the magnetic layer is formed on the back surface of the substrate opposite to the carbonized layer on the surface of the substrate, and the electrical resistance of the magnetic recording medium is sufficiently reduced and the electromagnetic conversion characteristics are sufficiently improved. Ru.

Ion implantation into a substrate made of a polymer compound is performed in a vacuum of about lXl0-5 to lXl0-', and the ion species is not particularly limited, such as A
Ions such as r+, N2'', Ti+, and Si are preferably used.In addition, when the acceleration voltage during ion implantation is lower than 10KV, the energy given to the ions is too small, Because the surface of the substrate made of a compound is not carbonized well, antistatic properties are not achieved sufficiently, and at an accelerating voltage higher than IOMV, the energy given to the ions is too large, causing them to pass through the substrate made of a polymer compound. Since a good antistatic effect cannot be obtained, it is preferably within the range of 10 KV to IOMV, and 5
It is more preferable to carry out at 0 to 5000 KV. The ion implantation amount under these conditions is 1013 ions/cl ~1
It is preferably within the range of 020 pieces/cIA, and 1
It is more preferable to set the number within the range of 015 pieces/C1 crystal to 1018 pieces/ad.

Carbonization of the surface of a substrate made of a polymer compound can be done by implanting ions as described above, but it can also be done by high-speed energy beams such as electron beams and radical beams. When the surface of a substrate made of a polymer compound is carbonized by high-speed energy rays such as ion, a carbonized layer is formed and the same effect can be obtained as in the case where carbonization is performed by implanting ions.

The thickness of the carbonized layer formed by carbonization of the surface of the substrate made of a polymer compound in this way is 100 to 10,000.
It is preferable that the thickness be within the range of a human body; if it is too thin, the desired effect will not be obtained, and if it is too thick, the base will become brittle and have an adverse effect on durability.

As the substrate made of a polymer compound, in addition to polyester, various engineering plastics such as polyamide, polysulfon, polyether sulfon, polyconythyl ether ketone ruphi 1-, etc. are suitably used.

The magnetic layer formed on the substrate is made of r-Fe203 powder, F
e304 powder, Co-containing T-Fe203 powder, Co-containing Fe304 powder, Fe powder, C.

5) Finally, metal magnetic powder such as Fe--Nj powder is coated on the substrate together with a binder resin and a proprietary solvent and dried, or CO, Ni, Fe, C, etc. are coated on the substrate.

-NiXCo-CrXCo-PXCo-Ni It is formed by depositing a ferromagnetic grain such as -NiXCo-CrXCo-PXCo-Ni-P on a substrate by means such as vacuum evaporation, ion blasting, sputtering, and plating. Note that it is also possible to directly carbonize the surface of the magnetic layer formed in this way to form a carbonized layer on the magnetic layer.In this case as well, the antistatic function is fully demonstrated, and noise generation due to charging is prevented. The increase in dropouts is effectively suppressed.

[Effect]

When a substrate made of a polymer compound whose surface is carbonized in this way and a carbonized layer is formed is used, and a magnetic layer is formed on the surface or back surface of this substrate on which the carbonized layer is formed, the amorphous layer formed on the surface of the substrate is The carbonized layer made of carbon fully exhibits its antistatic function, sufficiently reducing the electrical resistance of the magnetic recording medium, effectively suppressing the increase in noise and Trosopau I- due to charging, and preventing sticking during running. Not alive. In addition, when using a substrate made of a polymer compound whose surface is carbonized to form a carbonized layer, there is no need to include a large amount of carbon black or antistatic agent in the magnetic layer to prevent static electricity, and the surface This improves electromagnetic conversion characteristics, and since there is no need to form an undercoat layer or hack coat layer containing carbon black, the total thickness of the magnetic recording medium can be reduced. A magnetic recording medium having good electromagnetic conversion characteristics and capable of long-term recording and reproduction can be obtained.

〔Example〕

Next, embodiments of the present invention will be described.

Example 1 Using the ion implantation apparatus shown in FIG. 1, a polyester film 7 with a thickness of 15 μm was placed in the ion implantation chamber 6 of the ion implantation apparatus, and accelerated under the vacuum atmosphere of IXIO-61. 1013 Ar+ ions at a voltage of 300KV
Carbonization was performed by implanting Ca/Ca to form a 0.05 μm thick carbonized layer on the surface. Next, a magnetic paint prepared by mixing and dispersing the following composition in a ball mill for 72 hours was applied to the carbonized layer -1- on the surface of the polyester film 7 to a dry thickness of 5 μm, dried, and surface treated. After that, it was cut into 11 pieces to make magnetic tape.

Magnetic paint α-Fe magnetic powder (particle size 800 parts by weight 0, 3μ
m, axial ratio 7) Esresoku A (vinyl chloride-vinyl acetate-vinyl alcohol copolymer manufactured by Building Blocks Chemical Industry Co., Ltd. 9011)> ADEKA NEW ACE YT-400 55 〃 (polyester polyol manufactured by Asahi Denka Co., Ltd.) Corone-II7 (Nippon Boliureta 55 ARP-48 (manufactured by Sumitomo Chemical Co., Ltd. 60./Also
3 powder) myristic acid 15〃n-butyl stearate 10〃cyclohexanone
800 Toluene 8
05 Example 2 A magnetic tape was produced in the same manner as in Example 1 except that in the ion implantation in Example 1, the implantation method M of Ar+ ions into the polyester film 7 was set to 10151/coll.

Example 3 In the ion implantation in Example 1, Ar+ ions were implanted into the polyester film 7 including 11, 7+, . l to 10
A magnetic tape was produced in the same manner as in Example 1 except that the magnetic tape was 161 hard/cJ.

Comparative Example 1 Example 1 except that Ar + ions were not implanted into the polyester film, and 40 parts by weight of Conductexox (carbon blank manufactured by Columbia Carbon) was newly added to the composition of the magnetic paint. A magnetic tape was made in the same manner as in 1.

The magnetic tape obtained in each Example and Comparative Example was used with a Hitachi needle MVTR1VT-8200 with adjusted recording current value.
video S/N and dropout were measured. Dropout was expressed as an average value over 1 minute with a size of 5 μs or more.

The table below shows the results.

〔Effect of the invention〕

As is clear from the above table, the magnetic tapes obtained in Examples 1 to 3 have a higher
The video S/N ratio is high and the trosop-out is low, which indicates that the magnetic recording medium obtained by the present invention has low electrical resistance and excellent electromagnetic conversion characteristics.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an ion implantation device.

Claims (1)

[Scope of Claims] 1. A magnetic recording medium characterized in that a magnetic layer is provided on the front or back surface of a substrate made of a polymer compound having a carbonized layer on the surface. 2. A magnetic recording medium characterized in that a magnetic layer is provided on the surface of a substrate made of a polymer compound. The magnetic recording medium 3 according to claim 1, which is provided on a carbonized layer of, is prepared by implanting ions into the surface of a substrate made of a polymer compound in a vacuum atmosphere to improve the surface of the substrate made of a polymer compound. A method for manufacturing a magnetic recording medium, which comprises carbonizing to form a carbonized layer, and then forming a magnetic layer on the front or back surface of a substrate having the carbonized layer.