JPH03192514A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain both excellent electromagnetic conversion characteristics and stable traveling property by providing a thin-film resin layer on a plastic film substrate having fine projections on its surface, and forming a magnetic layer on the resin layer. CONSTITUTION:A plastic film 1 as a base has fine projections, on which a thin-film resin layer 2 is formed to such thickness not so different from the height of projections of the film 1. Further, a ferromagnetic metal thin film 3 and lubricant layer 5 are formed successively on the layer 2. A back coating layer 4 is formed on the other side of the film 1. Thereby, high quality recording/reproducing can be performed for pictures and sounds with little dropout, as well as stable traveling property can be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a ferromagnetic metal thin film type magnetic recording medium subjected to a surface treatment effective for producing high quality and highly reliable reproduced signals.

Conventional technology In recent years, in the field of magnetic recording, equipment has become more sophisticated and smaller.
Demand for high-density magnetic recording media has increased to promote longer recording times and digitalization, and in response to this demand, magnetic recording media composed of ferromagnetic metal thin films are being actively researched because they are advantageous for short wavelength recording. ing.

An effective means of achieving higher density in magnetic recording media is to smooth the surface of the recording medium to reduce spacing loss. However, if the surface of the magnetic head is made smooth, the magnetic head will come into close contact with the surface of the recording medium, which will impede its running performance. On the other hand, since the magnetic thin film type magnetic recording medium has a very thin magnetic layer of 0.1 to 0.5 .mu.m, the surface roughness of the medium with which the head comes into contact largely depends on the surface shape of the substrate. Therefore, attempts have been made to control the fine protrusions on the surface of the medium to smoothen the surface, reduce spelling loss, and improve head runnability.

For example, a magnetic recording medium has been proposed in which a resin solution containing fine particles of tens to hundreds of angstroms is coated on a plastic substrate, and a ferromagnetic metal thin film is formed on the substrate on which granular protrusions are formed. Examples include Japanese Patent Publication No. 1-32576, Japanese Patent Application Laid-open No. 59-488.
No. 26, JP-A-59-30231, JP-A-Sho 5
9-48825, etc.

Problems to be Solved by the Invention It is very difficult to uniformly disperse ultrafine particles on the substrate surface using such conventional methods, and it has been impossible to avoid coarse protrusions caused by agglomeration of the fine particles. These large protrusions widen the gap between the magnetic head and the recording medium, increasing spacing loss and causing reproduction signal dropouts.

The present invention solves the above problems, and aims to provide a magnetic recording medium that has both excellent electromagnetic conversion characteristics with little dropout and stable running performance.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a thin film-like resin layer having a thickness not significantly different from the height of the fine projections on a plastic film substrate having fine projections on the surface,
A magnetic layer made of a ferromagnetic metal thin film is formed on this resin layer.

Effect: The magnetic recording medium of the present invention has the above-described configuration, which prevents the fine particles and resin surface control material used for forming fine protrusions from being lost during the manufacturing process, and prevents the aggregation of fine particles present on the surface of the base film. The effective height is reduced by smoothing out the rough protrusions caused by the process.

Embodiment FIG. 1 is a sectional view showing the basic structure of an embodiment of the present invention in a magnetic tape.

In FIG. 1, reference numeral 1 denotes a base plastic film having projections formed of fine particles, and a thin resin layer 2, a ferromagnetic metal thin film 3, and a lubricant layer 5 are sequentially formed on the surface having the fine projections. A back coat 4 is formed on the opposite side of the plastic film 1.

The plastic film used in the present invention is often made of polyethylene terephthalate, but other plastics may also be used.

Further, the fine protrusions on the surface of the plastic film 10 serving as the base may have granular, wavy, or wrinkled protrusions, or a combination of granular protrusions and wavy or wrinkled protrusions.

As the material for forming the granular protrusions, inorganic particles such as silica, fine metal particles, carbon black, and fine resin particles such as acrylic or styrene are used.

The ferromagnetic metal thin film 3 is made of iron, cobalt, nickel, or an alloy containing these as main components by a normal film forming method such as electron beam evaporation, sputtering, or ion blating.

As a method for forming the thin resin layer 2 on the plastic film having minute protrusions, there is a conventional coating method, for example, a method using a nozzle coater, a reverse roll coater, or the like.

As the thin resin material, acrylic, urethane, polyester, cellulose, silicone, alkyd resins, etc. can be used.

The amount of resin to be applied should be within a range that does not reduce the effect of fine protrusions, and if the thickness of the thin resin layer 2 is too thin,
It has little effect in alleviating the negative effects of abnormal protrusions, and on the other hand, if it is too thick, it becomes unstable to ensure the running performance of the recording medium due to the fine protrusions. For this reason, the coating amount is 1■/-~1
It is preferable to carry out the reaction within a range of 00 .mu./ze, and more appropriate conditions can be determined experimentally.

Hereinafter, specific examples of the present invention and comparative examples will be explained while comparing them.

Example 1 Thermoplastic polyester (trade name: Vylon, manufactured by Toyobo Co., Ltd.) was applied at a coating amount of 15 m9/rd on the surface of a 10 μm thick polyethylene terephthalate film in which fine particle silica with a particle size of 260 particles was dispersed on the surface. Coating,
A thin resin layer was formed. Next, a film with a thickness of 15 cm was deposited on this film by oblique evaporation while introducing oxygen using an electron beam method.
000 Go-Ni-0 films were formed. Furthermore, a lubricating layer made of fluorine-based carboxylic acid was formed on the surface of the magnetic layer, and a back coat layer was formed on the opposite side of the polyerylene terephthalate film, and then the film was cut into 8-sized pieces to obtain a magnetic tape.

Example 2 As a base plastic film, the surface was coated with fine wrinkle-like protrusions mainly made of silicone resin and 180
A polyethylene terephthalate film having granular protrusions made of fine silica particles having a human particle size was used, and a coating amount of 5 m9/rr? was applied to the surface in the same manner as in Example 1. A thin film resin layer was formed under these conditions. Next, on this film, a film with a thickness of 1
500 Co-Ni-○ films were formed. Furthermore, a lubricating layer made of fluorine-based carboxylic acid was formed on the surface of the magnetic layer, and a back coat layer was formed on the opposite surface, and then cut into a width of 8+m to form a magnetic tape.

A conventional magnetic tape was prepared in the same manner as in Example 1-2 except that the thin resin layer was not formed. This will be referred to as Comparative Examples 1 and 2.

The magnetic tape obtained above was used as a commercially available 8 mV TR.
It was recorded and played back using a VTR tester with the same functions as the original, and dropouts and PCM error rates were measured.

The results are shown in the table.

Effects of the Invention As can be seen from the above examples, the magnetic tape of the present invention can record and reproduce high-quality images and sounds with fewer dropouts compared to conventional magnetic tapes. It also ensures stable running performance and has extremely high practical characteristics.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the magnetic tape according to the present invention. 1...Base film having fine protrusions, 2.
... Thin film resin layer, 3 ... Ferromagnetic metal thin film, 4 ... Back coat, 5 ... Lubricant layer.

Claims (1)

[Claims] A thin film resin layer having a thickness not significantly different from the height of the micro projections was provided on a plastic film substrate having fine projections on the surface, and a magnetic layer made of a ferromagnetic metal thin film was formed on the thin resin layer. magnetic recording medium.