JPS6038719A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a high density recording medium having extremely superior resistance to corrosion especially by moisture in the air by forming a metallic thin film of a ferromagnetic body on a substrate and by adsorbing phthalocyanine on the thin film. CONSTITUTION:A metallic thin film of a ferromagnetic body such as Ni-Co is formed on a substrate such as a polyester film, and phthalocyanine contg. Na, K or Ca is adsorbed on the magnetic thin film. The adsorption can be easily carried out by immersing the resulting magnetic recording medium in a soln. of metallic phthalocyanine in ethanol and by applying positive voltage to the magnetic thin film and negative voltage to the soln. A magnetic recording medium having superior corrosion resistance and gathering no rust even in an atmosphere at high temp. and humidity is obtd. The magnetic layer may be covered with a protective layer of Cr, Ti or Si oxide or nitride or may be coated with a lubricant such as ''Teflon'' or higher fatty acid so as to improve further the wear resistance and traveling performance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to magnetic recording media such as magnetic tape.

Magnetic recording media such as magnetic tapes, which are made by adhering ferromagnetic metals to a polymer film or other glue by vacuum evaporation to form a ferromagnetic thin film, have a higher recording density than conventional coated media, and have recently been commercialized. It has started to be done.

However, since the magnetic layer of such a magnetic recording medium is directly exposed to the air, it has the disadvantage that it is easily corroded by moisture in the air. In order to improve these drawbacks, a MW retention is usually provided on the surface of the ferromagnetic thin film, but the conventional protective film has the drawback of low corrosion resistance.

The object of the present invention is to overcome the above-mentioned drawbacks and provide a magnetic recording medium with improved corrosion resistance.

In order to achieve the above object, the present invention provides a magnetic recording medium in which a ferromagnetic thin film is formed on a substrate, in which a phthalocyanine is adsorbed to the ferromagnetic thin film. .

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

A polymer film such as polyester is used as the substrate. A ferromagnetic thin film is then formed on this substrate by obliquely depositing a ferromagnetic metal such as cobalt, iron, or nickel by vacuum evaporation, ion blasting, or sputtering. After forming a ferromagnetic thin film, phthalocyanine of metals such as sodium, potassium, beryllium, magnesium, calcium, barium, cadmium, titanium, chromium, etc., metal-free phthalocyanine, or their salts are adsorbed on the surface of this ferromagnetic R film. let

That is, according to the present invention, phthalocyanine having excellent corrosion resistance is adsorbed on the surface of the ferromagnetic thin film and its cracks, so that the corrosion resistance of the magnetic recording medium is improved.

J3, after adsorbing phthalocyanine etc. to the ferromagnetic thin film,
The third layer is made of inorganic materials such as oxides and nitrides such as chromium, titanium, and silicon, materials with higher alkyl groups such as fluorine-based resins such as Teflon, materials such as polyimide, stearic acid and behenyl. It may be formed by applying or vapor depositing a substance such as a higher fatty acid such as an acid.

For example, a ferromagnetic thin film consisting of 80% cobalt and 20% nickel is formed on a polynisder film by diagonal vapor deposition in vacuum, and then metal phthalocyanine of sodium (helium), magnesium, calcium, zinc, and copper is formed.
．． Examples of the present invention in which the ferromagnetic thin film was immersed in an ethanol solution containing 1% ferromagnetic acid, a positive voltage was applied, and a negative voltage was applied to the liquid to adsorb phthalocyanine. A comparative example manufactured in the same manner as the inventive example except for the above was subjected to a test in which it was left in an atmosphere at a relative humidity of 90% and a temperature of 60°C. While no rust occurred, the latter had already rusted after a week. In particular, the examples of the present invention using sodium, potassium, magnesium, and calcium phthalocyanines did not rust even after two weeks, and were found to have excellent corrosion resistance.

As described above, according to the present invention, a magnetic recording medium with excellent corrosion resistance can be obtained.

Patent applicant: Hitachi Capacitor Co., Ltd.

Claims (2)

[Claims] (1) A magnetic recording medium having a ferromagnetic thin film formed on a substrate, characterized in that phthalocyanine is adsorbed to the ferromagnetic thin film. (2) The magnetic recording medium according to claim 1, wherein the phthalocyanine is a metal phthalocyanine containing at least one of sodium, potassium, magnesium, or calcium.