JPS6066320A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium which improves Young's modulus, permits easy removal of curling and improves runnability, etc. by providing underlying layers consisting of the same kind of nonmagnetic metal or the compd. thereof on both surfaces of a base body and providing a ferromagnetic metallic film on one underlying layer. CONSTITUTION:Underlying layers are formed on both surfaces of a base body consisting of a polyester film, etc. by vacuum deposition, etc. of the same kind of nonmagnetic metal, for example, Al and Zn, Sn, Cr, Ti, etc. or the oxide and nitride thereof. The one underlying layer is made, for example, about 500Angstrom , and a ferromagnetic metallic film is formed thereon to about 1,000Angstrom . The other underlying layer is made about 1,500Angstrom thick and a resin contg. a fatty acid is coated thereon to provide a lubricating layer for the better result. The Young's modulus of the magnetic recording medium is thus improved and the rates of shrinkage on both surfaces are made the same, by which the removal of curling, etc. is made easy and the runnability, durability, etc. are improved.

Description

[Detailed description of the invention] The present invention relates to magnetic recording media.

In the past, coated type magnetic recording media such as magnetic tapes and magnetic disks were mainly used, but recently, thin film type types in which ferromagnetic metal is attached to a substrate by vacuum evaporation method, ion plating method, etc. has come to be used instead.

By the way, when using magnetic tape, etc., a certain Young's modulus is required for running properties, etc., or thin-film type tapes do not have a structure of just a layer of ferromagnetic metal thin film on the base. It has the disadvantage of having a small Young's modulus.

The object of the present invention is to provide a magnetic recording medium that can improve the above-mentioned drawbacks and increase the A7 size.

In order to achieve the above object, the present invention provides a magnetic recording medium in which a ferromagnetic metal thin film is provided on the L1 body, and a substrate made of the same type of non-magnetic metal or a compound thereof on both sides of the base body. The present invention provides a magnetic recording medium characterized by the provision of a geological layer.

The present invention will be explained below based on examples.

As the substrate, a polymer film such as a polyester film or a polyethylene terephthalate film is used. And the same l on both sides of this base! A base layer is provided by vacuum evaporation of a nonmagnetic metal of type I or a compound thereof. As the non-magnetic metal, Δ, Zn S3n, Or, 7i, etc. are used, and as the compound, oxides or nitrides of these non-magnetic metals are used. A ferromagnetic metal thin film such as iron, cobalt, or nickel is deposited on one of the underlayers by vacuum evaporation, ion blasting, sputtering, or the like. A protective layer is further applied to the ferromagnetic metal thin film by applying a higher fatty acid such as stearic acid or behenic acid.

Further, a substance in which carbon black, fatty acid, etc. are mixed with resin is applied to the underlayer on the opposite side to the underlayer on which the ferromagnetic metal thin film is provided to form a lubricating layer.

That is, according to the present invention, since the base layer made of non-magnetic metal or the like is provided on both sides of the substrate, the Young's modulus of the magnetic recording medium is improved and the running properties etc. are improved. In particular, when the underlayer is formed by vapor deposition of non-magnetic metal, etc.
There is a limit to the thickness, and it is one-sided (even if such a base layer is provided on the surface, it may be too thin and the specified A7 rate cannot be achieved, but with the present invention, it can be applied on both sides). Therefore, the Young's modulus can be further increased and a predetermined value can be obtained freely.

In addition, since the underlayers provided on both sides of the substrate are made of the same type of material, the shrinkage rate on both sides is the same, and the conditions for curl removal treatment when a ferromagnetic metal thin film, etc. is subsequently provided, etc. This makes it easier to manufacture magnetic recording media.

For example, a polyester film with a thickness of 12 μm is used as the base layer, an oxide of A1 is used as the base layer, and one layer is made with a thickness of 500 μm.
The other layer was formed to a thickness of 1500 Δ, and a ferromagnetic metal thin film with a thickness of 1000 Δ was formed by depositing a ferromagnetic metal at a ratio of Co:Ni = 8:2 on the thinner underlayer by vacuum evaporation. When the A angle rate was measured for the conventional example in which the other conditions were the same as the example of the present invention, the former was 750 Kt/mrn' and the latter was 450 Kg.
/ mm' and 41, the Young's modulus according to the present invention is increased by about 1.7 times.

Note that oxides and nitrides of nonmagnetic metals are more preferable as materials for the underlayer because they can increase the Young's modulus more than nonmagnetic metals.

As described above, according to the present invention, a magnetic recording medium can be obtained in which the A7 rate can be increased, a predetermined value can be easily obtained, the running properties can be improved, and the magnetic recording medium can be easily manufactured.

Patent applicant: Hitachi Kondenri Co., Ltd.

Claims (1)

[Claims] (1) A magnetic recording medium in which a ferromagnetic metal thin film is stepped on a substrate, and an underlayer made of the same type of non-magnetic metal or a compound thereof is provided on both sides of the substrate. magnetic recording media. f2) The magnetic recording medium according to claim 1, wherein the nonmagnetic metal compound is an oxide. (3) The magnetic recording medium according to claim 12I7, wherein the nonmagnetic metal compound is a nitride.