JPS59124024A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent the formation of pinholes due to the sticking of dust and the formation of vertical creases and to reduce an output change by forming a photoconductive resin layer on a base and by depositing a magnetic thin metallic film on the resin layer by vapor deposition while irradiating light so as to prevent the electrification of the base. CONSTITUTION:When a high magnetic alloy of Co, Mi or the like is vapor- deposited on the base film of a magnetic tape or the like while transferring the film along the outside of a rotating can, the film may be electrified, by the effect of secondary electrons from the evaporating source or the slippage of the film due to the difference in speed between it and the can. In order to prevent the electrification, a photoconductive resin layer is formed on the base film by applying and drying a soln. of the nitrated product of poly-9-vinylcarbazole, and a magnetic thin metallic film is deposited on the resin layer by vapor deposition while irradiating light. Thus, the sticking of dust and the formation of creases are prevented by the electrification of the base film, so the resulting magnetic layer is made free from defects such as pinholes, and an output change is inhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to magnetic tapes and other magnetic recording media having a magnetic metal vapor deposited film.

Traditionally, this type of media has generally been produced by running a base, such as a polyester film, over a rotating can via rollers.
It is manufactured by heating and vapor-depositing a highly magnetic metal such as Go or Ni under vacuum.

However, with this method, the base film becomes electrically charged due to the influence of secondary electrons from the evaporation source, and the film elongates due to thermal expansion, causing slippage due to the speed difference between the rotating can and the traveling film. It can also be charged with electricity.

When such a charge occurs, dust and other impurities tend to adhere to the evaporation surface of the base irradiation, causing the magnetic evaporation film to deteriorate.
This causes pinholes to form in the film, and the running film tends to cling to the rotating can, which tends to cause vertical wrinkles in the film. As a result, the resulting magnetic tape has relatively large output fluctuations and cannot be used as a high-performance magnetic tape.

This invention was made with the aim of avoiding such problems, and its gist is that a photoconductive resin layer is provided on a base and a layer is vapor-deposited on this layer while being irradiated with light. A magnetic recording medium is characterized in that it has a magnetic metal vapor deposited film.

That is, in this invention, a photoconductive resin layer is provided on the deposition surface of the base, and the magnetic Tanikaze is deposited while irradiating this layer with light. is suppressed, and as a result, a magnetic recording medium with small output fluctuations can be obtained.

In this invention, a paint containing a photoconductive resin is first applied onto a base such as a polyester film, and generally a coating material containing a photoconductive resin is coated on a base such as a polyester film.
The resin layer is formed to have a thickness of about 1 to 2 μm. The photoconductive resin used herein means a resin that becomes conductive when irradiated with light, and specific examples thereof include poly-9-vinylcarbazole, polyacenaphthylene, polyvinylnaphthalene, etc. The degree of nitration of nitration is 0.5~
2Q m O1%), N-vinylcarbazole-vinylmalachite green copolymer, polyacetylene, polyacrylonitrile and heat-treated products thereof, polyvinylanthracene, polyacenaphthylene, polyvinylpyrene, and the like. These resins themselves are conventionally known.

After forming such a photoconductive resin layer, a ferromagnetic metal such as magnetic metal iron or magnetic metal cobalt is deposited on this resin layer by a conventional method. By making the resin layer conductive by irradiating the surface of the resin layer, a magnetic recording medium with little output fluctuation, which is the object of the present invention, can be obtained. Alternatively, a non-magnetic metal vapor deposited film such as A i or Cr may be provided between the photoconductive resin layer and the magnetic metal vapor deposited film. In this case, the same light irradiation as described above is performed during vapor deposition. The latter evaporated film gives good results in uniform evaporation of magnetic metal and control of the evaporated film thickness.

EXAMPLES Below, examples of the present invention will be described in more detail.

Example A polyester film with a thickness of 10 μm was coated on one side of the polyester film.
A coating material consisting of 3 parts by weight of a nitrated product of 9-vinylcarbazole (degree of thoration: 12 mol %) and 97 parts by weight of chlorobenzene was applied and dried by heating to form a photoconductive resin layer with a thickness of 0.2 μm.

Next, the base on which the photoconductive resin layer was formed was set in a vacuum system, and the base was moved at a speed of 0.5 m/min so that the opposite side of the resin layer was in contact with the rotating can, and the tungsten lamp was While irradiating with light, Co metal was vacuum-deposited onto the surface of the resin layer from an oblique direction at an incident angle of 50 degrees to form a magnetic metal deposited film having a thickness of about 1.000 A and a coercive force of about 1.150 oersteds.

The magnetic tape thus obtained was loaded into a video tape recorder VT-8000 (manufactured by Hitachi), and heated at 40°C.
The results of examining the output fluctuations after running 200 times at 80% RH were as follows.

Note that the comparative example below is the result of a magnetic tape produced in exactly the same manner as the example except that the photoconductive resin layer was not provided.

Output variation example: ±0.5 dB Comparative example: ±1.2 c113 As is clear from the above results, according to the present invention, a magnetic tape with small output variation and suppressed charging during vapor deposition can be obtained. I understand.

Patent applicant: Hitachi Maxell, Ltd. Agent: Patent attorney Moto Kunio Negi

Claims (1)

[Claims] (1) A magnetic recording medium comprising a photoconductive resin layer provided on a base and a magnetic metal vapor deposition film formed on this layer while irradiating it with light.