JPS62236125A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the flatness and environmental stability of the titled medium by flattening the first film obtained by providing a ferromagnetic metallic thin film on a polymeric film and the second film obtained by furnishing a thin film on a polymeric film, and sticking both films on each other. CONSTITUTION:The first film obtained by providing a ferromagnetic metallic thin film 7 on a polymeric film 5 and the second film obtained by furnishing a thin film 8 on a polymeric film 6 are flattened, and both films are stuck on each other. The film of polypropylene, polycarbonate, polyether sulfone, or a combination of the resins as well as a polyethylene terephthalate film can be used as the polymeric film. Since a flat magnetic recording medium without any dimensional change and having high mechanical strength can be obtained in this way, recording and producing of short-wave record can be performed in wide environment with excellent S/N.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium suitable for high-density magnetic recording.

Conventional technology In recent years, advances in high-density magnetic recording have been remarkable, and coated magnetic layers in which fine ferromagnetic particles are dispersed and fixed in a binder have suppressed the drop in short wavelength output by increasing coercive force and smoothing the surface. However, when the recording wavelength becomes about O.S μm, it is impossible to obtain a practical signal-to-output ratio (hereinafter referred to as S/N), and so-called thin-film magnetic Recording media are attracting attention as a promising medium for improving recording density through shorter wavelengths and narrower tracks. (For example, the foreign journal IEE Magnetics Society Bulletin (IKICΣ TRANSACTIONSON)
MAGNICTIC8) Vol, MAG-21, NO
,3.

P, P1217-1220 (1985)) Such a medium has several characteristics different from a conventional medium using a coated magnetic layer.

One is the characteristics of the manufacturing method.Since the ferromagnetic metal thin film is formed using a vacuum evaporation method, the thin film's shrinkage stress, compressive stress, etc.
This can cause cupping (flattening)
In Fusen, after vapor deposition, the polymer film that is the substrate is heat-shrinked to eliminate the appearance of cupping.

However, it has a two-layered structure consisting of a polymer film and a metal thin film with significantly different coefficients of thermal expansion, which causes cupping changes in response to temperature changes, so in order to absorb this change, high A magnetic recording medium has been proposed in which vapor deposited layers are placed on both sides of a molecular film.

Problems to be Solved by the Invention However, as shown in FIG. 2, the magnetic recording medium having the above-mentioned structure has a ferromagnetic metal thin film 2 and a protective film 4 on one side of a polymer film 1, and a vapor-deposited film on the other side. With the structure in which the membrane 3 is arranged, it is possible to obtain a medium with apparently less cupping, but it is difficult to control manufacturing conditions and it is difficult to construct a long medium in a flat state.

In particular, as the total thickness of the medium becomes smaller, flattening becomes difficult, and the thermal effects of the two vapor deposition processes in total can significantly reduce the mechanical strength of the polymer film.To prevent this, polyimide, etc. It is necessary to use a polymer film with high heat resistance, which lacks versatility.

The present invention was made in view of the above circumstances, and it is an object of the present invention to provide a magnetic recording medium that has good flatness, excellent environmental stability, and can be mass-produced using a highly versatile polymer film such as polyester. Means for Solving Certain Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention comprises a first magnetic recording medium in which a ferromagnetic metal thin film is disposed on a polymer film.
This film is made by flattening the film and a second film in which a thin film is disposed on a polymer film, and then bonding them together.

Function: The magnetic recording medium of the present invention has the above-described structure, and since it has a structure in which the respective planarized pieces are bonded together, it has excellent flatness and is stable against temperature changes. Furthermore, since the vapor deposition process is performed once for each polymer film, there is little heat influence, and highly versatile polymer films such as polyester films can be constructed.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an enlarged sectional view of the magnetic recording medium of the present invention. In FIG. 1, 6.6 is a polymer film, 7 is a ferromagnetic metal thin film which is a magnetic recording layer, and 8 is a thin film, and the materials are not limited.

Each of the polymer films 5.6 is constructed by being subjected to a flattening treatment by heat treatment. 9 is the adhesive layer, 10
is a protective layer.

Using polyethylene terephthalate film with a thickness of 6.5 μm and a surface roughness of 100, the diameter is 11! CoN was poured into a cylindrical can of I in an oxygen partial pressure of 4 x 10 Torr.
Electron beam evaporation was performed at i (Ni 20 wt%) i 4 μm/Sea to form a Co-Ni-0 magnetic recording layer having a coercive force of 1200 (Os) and a thickness of 0.1 μm.

This was used as a first film, ie, a mu film, and was heat treated to make it more flat.

Furthermore, NJlo, 17! 13.56 MHz at about 3X10 TOrr while installing /win
Al f 4 μ in an atmosphere that generated a glow discharge of
The heat treatment temperature of the 0μ film was 105°C, and the heat treatment temperature of the B film was 105°C. The temperature was 88°C.

After the A film and the B film were bonded together using epoxy resin 9, about 4Q of perfluorooctanoic acid was vacuum-deposited as a protective layer 1o.

This film was cut into 8 mm width to produce a magnetic tape.

As a comparative example, the thickness was 10 μm and the surface roughness was io.

The same magnetic recording layer as in this example was formed on a human polyethylene terephthalate film, and a SiO film of about 0.16 μm was evaporated on the opposite side to the magnetic recording layer to form the same protective film as in the wall example. A magnetic tape with a width of 1 mm was manufactured.

A comprehensive comparison was made regarding both.

The recording equipment used was a commercially available 8mm video product.

First, PCM recording was performed at 20° C. and 604 RH, and the data was stored and played back in various environments. 40”C80%R)! 2 months, 5
0"C804RH After storage for 37 months, the noise of this example did not increase, but the noise of the comparative example increased noticeably. This is thought to be due to skew.

Recording was performed at a recording wavelength of 0.8 μmf, and modulation noise was examined. 4
When reproduction was repeated 150 times at 0°C and 80% RH, noise did not increase in this example, but modulation noise increased in the comparative example. This is due to cracks in the ferromagnetic thin film. This is probably because the mechanical strength of the comparative example deteriorated significantly due to thermal deterioration during the processing process. Other materials include polypropylene, polycarbonate, and polyether sulfonate. It may be made of polyamide alone or in combination.

A Go-Ni-049 film was used as the magnetic recording layer, but Go-Fe, Go-Or, Go-Pt were also used.
, Go-Ru, etc., in-plane magnetized film, Go-Or,
Go-W, Go-Mo, Go-Cr-N
It may also be a perpendicular magnetization film such as Go-0 or Go-0.

The thin film was MuIN, but in addition, 5i5N4. Mu1205.
MgO.

It may also be TiO2, Ni-Cr, C, Tie, etc.

Effects of the Invention As described above, according to the present invention, a flat magnetic recording medium with no dimensional change and strong mechanical strength can be obtained, so that short wavelength recording can be performed with good S/N in a wide range of environments. This provides excellent effects such as being able to perform recording and playback.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of a magnetic recording medium of the present invention, and FIG. 2 is an enlarged sectional view of a conventional magnetic recording medium. 6.6...Polymer film, 7...Ferromagnetic metal wire film, 8...Thin film, 9...Adhesive layer, 10...・Protective layer 0

Claims (1)

[Claims] A magnetic recording medium characterized in that a first film in which a ferromagnetic metal thin film is disposed on a polymer film and a second film in which a thin ferromagnetic metal film is disposed on a polymer film are bonded together after being flattened.