JPS618736A - Manufacture of magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the corrosion resistance without deteriorating the traveling property by forming a ferromagnetic metallic thin film and a protective layer in order on a broad strip-shaped substrate, cutting into specified width, rolling to obtain a rolled body, depositing a protective agent on the side surface of the rolled body, and then removing only the protecting agent on the side surface of the substrate. CONSTITUTION:A ferromagnetic metallic thin film 8 and a protective layer 7 are formed in order on a broad strip-shaped substrate 1 of a plastic film, etc., and the material is cut into a magnetic tape of specified width to obtain a rolled body 2. A protective agent 4 of high mol.wt. fatty acid ester, etc. is coated on the side surface 5 of the rolled body 2, dried, and cured. Then only the protective agent 6 deposited on the side surface 5 of the substrate 1 is removed by using a suitable solvent such as a mixed liquid of toluene and alcohol or by brushing, etc., and the protective agent 4 on the side surface part 9 of the metallic thin film 8 and of the protective layer 7 is left. Consequently, the corrosion due to the moisture or O2 in air, etc. from the side surface part 9 of the ferromagnetic metallic thin film 8 is prevented, and further the traveling property is not deteriorated.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to magnetic recording media.

(Prior art) Thin-film magnetic recording media, in which a thin ferromagnetic metal film is formed on a substrate such as a plastic film, have the advantage of higher magnetic recording density and miniaturization compared to conventional coated media. However, it has the disadvantage of poor corrosion resistance. For this purpose, a protective aIH made of a polymeric material or the like is usually formed on the surface of the ferromagnetic metal 11M1s.

By the way, when mass producing magnetic recording media such as magnetic tapes, after forming a ferromagnetic metal thin film and a protective layer on a wide substrate,
This base body is cut into predetermined lengths and wound into a roll.

However, when the substrate is cut, the mI in the vicinity of the cut is reduced! l
There was a drawback that part of the ferromagnetic gold FF thin film was peeled off, exposing the ferromagnetic gold FF thin film, and making it susceptible to corrosion.

In order to improve such defects, there is an invention in which a protective layer is provided by applying a protective agent to both side surfaces of each body, but this protective layer has the disadvantage that running properties are reduced.

(Objective) An object of the present invention is to provide a method for manufacturing a magnetic recording medium that improves the above-mentioned drawbacks, improves corrosion resistance and runnability, and is durable.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a magnetic recording medium in which a ferromagnetic metal thin film is formed on a strip-shaped substrate and a protective layer is further formed on the surface of the ferromagnetic metal thin film. In the manufacturing method, the step of cutting the substrate into a roll-shaped wound body after forming the protective layer, the step of attaching a protective agent to the side surface of the substrate after the step, and the step of applying the protective agent to the side surface of the substrate after the step, The present invention provides a method for manufacturing a magnetic recording medium, which comprises a step of removing the protective agent attached to the end face of a rotating body.

(Function) First, iron or cobal [
~ A ferromagnetic metal thin film is formed by depositing a ferromagnetic metal such as nickel by a vacuum evaporation method, an ion blating method, a sputtering method, or the like. After forming a ferromagnetic gold rif4S film on the substrate, a protective layer is formed by coating the surface with a polymer compound such as a higher fatty acid. After forming the protective layer,
The substrate is cut to a predetermined riJ and wound into a roll. Then, as shown in FIG. 1, a protective agent 4 such as a polymer compound is applied to the side surface 3 of the wound body 2, which becomes the cut surface of the base 1. After the protective agent 4 has been applied, as shown in FIG. 2, the protective agent 6 that has adhered only to the side surface 5 of the wound body 2 is removed by rubbing with a solvent or the like or with a brush or the like. Reference numeral 7 denotes a protective layer formed on the surface of the ferromagnetic metal itI film 8.

That is, according to the present invention, the substrate 1 of the ferromagnetic metal thin film 8
Since the protective agent 4 can be efficiently coated on the exposed portion 9 when the material is cut in a predetermined manner, corrosion resistance is improved.

Note that if the protective agent 6 that is stained only on the side surface 5 of the wound body 2 is left without being removed, the end surface of the ferromagnetic metal thin film 8 will not be exposed to the air, and the corrosion resistance will be further improved. Since the protective agent 3 is applied to the wound body 2, it is difficult to unravel the wound body 2, and cracks may occur in the thin ferromagnetic metal pA8, or the running properties may be deteriorated, which is not preferable.

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

A polyethylene terephthalate film with a thickness of 12μ and a width of 6Qcm was used as the substrate, and Co:Nt was deposited by vacuum evaporation.
=8: Deposit the ferromagnetic metal of 2 to form a ferromagnetic metal thin film with a thickness of 100A, and then coat with higher fatty acid etc.
1, +T protective layer is formed and wound to form a wound body. After forming the rolled body, cut it into 1/2 inch riJ, apply a protective agent such as fatty acid Nisdel on the side surface, and after curing, coat the protective agent on the side surface only with Jζ in a solvent such as toluene or alcohol. Remove.

The corrosion resistance and runnability of the magnetic tape of the embodiment of the present invention and the conventional example manufactured in this way were investigated, and the results shown in the table were obtained.

Regarding corrosion resistance, the results are shown by observing the surface with the naked eye after being left in an atmosphere at a temperature of 80° C. and relative humidity of 90% for one month, and regarding wow and flutter, the results were measured according to JIS5550. In addition, as for the conventional examples, 1) is a magnetic tape in which the protective agent treatment on the side surface is omitted after cutting the wound body, and 2) is a magnetic tape in which the protective agent attached to the side surface is left without being removed. As is clear from the above, according to the present invention, corrosion resistance is excellent and wow and flutter are improved.

(Effects) As described above, according to the present invention, a method for manufacturing a magnetic recording medium that can improve corrosion resistance and runnability can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of the wound body after removing the protective agent according to the example of the present invention, and FIG. 2 is a front sectional view of the wound body after the protective agent has been removed according to the example of the present invention. DESCRIPTION OF SYMBOLS 1... Base body, 2... Winding body, 3... Side part,
4.6... Protective agent, 5... Side surface, 7... Ferromagnetic metal thin film.

Claims (1)

[Claims] (1) In a method for manufacturing a magnetic recording medium in which a ferromagnetic metal thin film is formed on a strip-shaped substrate and a protective layer is further formed on the surface of the ferromagnetic metal thin film, the substrate is cut into a roll shape with a predetermined width after the protective layer is formed. a step of applying a protective agent to the side surface of the wound body after the step, and a step of removing the protective agent adhered to the side surface of the wound body after the step. A method of manufacturing a magnetic recording medium, characterized in that: