JPS60182514A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the adhesion of protective layers to a thin ferromagnetic metallic film and to eliminate the exfoliation of said layers by making the m.p. of the lowermost protective layer higher than the m.p. of the protective layer thereon in the stage of forming said magnetic film on a substrate and forming >=2 layers of the protective layers thereon. CONSTITUTION:A thin ferromagnetic metallic film consisting of Co, Cr, Ni, etc. is formed on a high polymer film substrate 1 consisting of polyester, etc. and thereafter the 1st protective layer 3 is formed thereon by coating the soln. or melt of a fatty acid having a high m.p. such as behenic acid or the like thereon. The 2nd protective layer 4 is then formed on the layer 3 by coating the soln. or melt of an acid having the m.p. lower than the m.p. of the layer 3, such as palmitic acid, stearic acid or the like thereon. The material having the m.p. higher than the m.p. of the protective layer on the lowermost protective layer is used for the lowermost layer and the upper protective layers are laminated into >=1 layers thereon to make the lowermost layer 3 hardly strippable even if the upper protective layer exfoliates. The corrosion and wear of the film 2 are thus prevented and the long period recording medium is obtd.

Description

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

A type of magnetic recording media such as magnetic tapes and magnetic disks.
There are thin film type magnetic recording media in which a ferromagnetic metal thin film is formed on a substrate such as a polymer film by vacuum evaporation or ion plating. A protective film is usually installed to prevent corrosion of the thin ferromagnetic Ilφ, and conventionally, this protective film has been made of an organic substance and coated with a lubricant such as 6th class fatty acid. However, such conventional protective films have a drawback that they have low adhesion to the ferromagnetic metal thin film and are easily peeled off.

The object of the present invention is to improve the above-mentioned drawbacks and provide a magnetic recording medium that has a protective layer that is difficult to peel off.

In order to achieve the above object, the present invention provides a magnetic recording medium in which a ferromagnetic metal thin film and two or more protective layers are formed on a base, in which a base protective layer is laminated on the protective layer. Another object of the present invention is to provide a magnetic recording medium characterized by a melting point higher than that of the overlying protective layer.

Hereinafter, the present invention will be explained based on embodiments.

At d5 in FIG. 1, reference numeral 1 denotes a base C made of a polymer film such as polyester or polypropylene.

2 is a ferromagnetic gold 1.7rS thin film laminated on this substrate 1, and a ferromagnetic metal such as Kobal 1~, chromium, Niracle, etc. is deposited on the substrate 1 by vacuum evaporation, ion plating, sputtering, etc. It is formed by adhering to.

3 is formed by applying a solution or melt of the first retaining acid that is directly laminated on the ferromagnetic metal film 2, or by applying an odorless coating or the like. 4 is a second protective layer laminated on the first protective layer 3, which is made of a solution of higher fatty acids such as valmitic acid and sudearic acid.
' It is formed by applying a Jiff Mar solution or by vapor deposition. In particular, the first protection Th'i d is the second protection layer 4
114 made from a substance with a higher melting point than iJ3
For that purpose, substances with different melting points are used, or even substances of the same type are converted into amorphous substances so that the melting point can be changed. 7.
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In other words, in the present invention, the first protective layer 3 and the second protective layer 4 have a melting point of 5, and the former has a higher melting point, so
When rubbed by the magnetic head AP, the melting point of the underlying first protective layer 103 is J, even if the second protective layer 4 on the upper layer peels off.
Because of its high resistance, it will not peel off and the ferromagnetic metal + TV film 2 will be protected from corrosion and abrasion.

In the example described above, the protective layer is two layers, or the cumulative film of three or more layers C<, in this case, one ferromagnetic metal source is used! As it approaches (81: point (7),!'B, ugly thing? 1, it is also spelled as having only the part near the surface made of a substance with a low melting point.

Further, another intermediate layer may be provided between the ferromagnetic metal thin film and the protective layer.

As described above, according to the present invention, there is a magnetic recording medium that can improve the peel strength of the protective layer, prevent damage to the ferromagnetic metal thin film, and improve the corrosion resistance! '7.

[Brief explanation of drawings]

The figure shows a cross-sectional view of an embodiment of the invention. 1...Substrate, 2...Ferromagnetic metal thin film, 3...1st carrier 3! layer, 1...second protective layer.

Claims (1)

[Claims] (1) In a magnetic recording medium in which a ferromagnetic metal thin film and two or more protective layers are formed on a substrate, the underlying protective layer has a higher melting point than the upper protective layer laminated on the protective layer. A magnetic recording medium characterized by: