JPS6025803B2 - Metal thin film magnetic tape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the improvement of a metal thin film magnetic tape for high-density magnetic recording. The purpose is to provide certain characteristics.

Conventional so-called coated magnetic tapes, in which ferromagnetic powders such as y-Fe203 and Cr02 are mixed with a binder, coated, and cured, have also been improved to meet the needs for short wavelength recording, and uniform dispersion technology has been developed along with improved holding power. We have been working to improve this.

On the other hand, post-coating treatment techniques have also been improved, and efforts have been made to reduce surface roughness. Regarding this surface roughness, in the case of metal thin film magnetic tapes, efforts are being made to smooth the base material since it depends on the surface roughness of the base material, but this has the disadvantage of reducing the adhesion strength of the thin film. .

In view of this point, the inventor has made careful consideration and found that
It has been found that there is a limit to merely improving the conventionally known linear average roughness and maximum roughness while taking into account the above-mentioned adhesive strength aspect.

This is the phenomenon in which the output level decreases due to repeated running as shown in FIG. This phenomenon was the same for films obtained by electrolytic plating, vacuum evaporation, sputtering, or ion plating on polymer molded substrates such as general-purpose polyethylene terephthalate.

What had a particularly remarkable effect on improving this point was the shape of the metal particles added to the base material, which were spherical or nearly ellipsoidal (preferably with a maximum/minor axis ratio of 2'1 or less). can be,
In addition, the average particle diameter was selected in relation to the recording wavelength, which will be described later.

This point will be further explained in detail with reference to examples.

In FIG. 1, 1 is a magnetic metal layer, 2 is an underlayer, and 3 is a polymer molded base material to which metal particles 4 having an average particle size smaller than the recording wavelength are added. Of course, it is not limited to this, and any structure that has already been proposed, such as a protective layer or a multi-layered magnetic layer, may be used, and basically any metal thin film structure will have an effect.

The base material 3 shown in FIG. 1 brings out the effects of the present invention, and fine metal particles 4 are added to the base material 3 to give it a boar resistance and antistatic effect, and in particular to keep the particle size below the recording wavelength. As a result, as shown in FIG. 2, a decrease in the output level can be prevented compared to the conventional one. Here, the relationship between the average grain size of fine metal particles and the recording wavelength will be further described.

FIG. 3 is a graph showing output characteristics versus average particle diameter of metal fine particles when recording wavelength input is used as a parameter.

It can be seen from the figure that no decrease in output is observed when the average particle diameter is less than the recording wavelength. Base layer 2 is made of Cro. 05
The magnetic metal layer 1 is made of CONi (Co group%Ni2%
)0.121 is an example.

Nao Cro. The CONi layer was obtained by high-frequency sputtering method in an atmosphere of 0.05 yen Arl x 10-3 Ton, and the CONi layer was 4 x 10-
It was obtained by electron beam evaporation in a 5 ton oxygen atmosphere. Regarding the base layer 2, electron beam evaporation method and ion plating method were also performed, but 100%
Even after turning around, the temperature was within 1 lull.

Regarding material dependence, in addition to Cr, Ag, An, A〆,
We have investigated Sj, Ti, W, Mo, ln, Sn, etc., and have confirmed that there is no significant difference. The same is true for the magnetic metal layer 1, and it has been confirmed that the same tendency is observed for the magnetic metal layer 1, which is mainly composed of Fe, Co, and Ni, and in which non-magnetic materials are added.

As shown in the table below, the base material 3 of the present invention has the effect of increasing the holding power, which is essential for high-density recording, by providing the base layer 2 of the same material as the metal fine particles 4 to be added. Compared to polyethylene terephthalate containing general-purpose additives such as , Aso203, Si02, etc., it is promising as a base material for densification regardless of the presence or absence of a base. Sho An, Ag
In addition to metal fine particles 4 with excellent tenacity, it is of course effective for W, Mo, etc., and can also be applied to those whose surfaces are slightly oxidized for stabilization, as well as polycarbonate, polyimide, polyamide, etc. The same applies to

In any case, the effects of the present invention are large, and can cover the essential defects of metal thin films, which have particularly stress-sensitive characteristics, and have great industrial value.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the metal thin film magnetic tape of the present invention, FIG. 2 is a relative output level characteristic diagram with respect to the number of runs of the metal thin film magnetic recording medium of the present invention and the conventional metal thin film magnetic recording medium.
The figure is a relative output level characteristic diagram with respect to the average particle size of fine metal particles in the polymer molded material. 1...Magnetic metal notification, 2...Underlayer, 3
... Polymer molded product base material, 4 ... Metal fine particles. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. In a metal thin film magnetic tape formed by providing at least one magnetic metal layer on a polymer molded base material, the average particle size of metal fine particles added to the polymer molded base material is recorded. Metal thin film type magnetic tape characterized by being below the wavelength. 2. The metal thin film magnetic tape according to claim 1, wherein the base layer is a non-magnetic layer that is the same as the main material of the metal fine particles added to the polymer molded substrate.