JPS6254825A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To form a magnetic recording medium having durability with a small spacing loss even if an alloy head is used by successively laminating thin films, plasma-polymerized films and lubricating layers on both faces of a high-polymer film and ansisting at least one of the thin films of a thin ferromagnetic metallic film. CONSTITUTION:This medium is constituted by disposing the thin films 7, 8, the plasma-polymerized films 9, 10 and the lubricating layers 11, 12 on both faces of the high-polymer film 6 and consisting at least one of the thin films of the thin ferromagnetic metallic film 7. The lubricants 11, 12 exist at an approximately equal amt. on both faces; therefore, the load of the alloy head on the plasma-polymerized films 9, 10 is always relieved even if the medium constituted in the above-mentioned manner is wound like a tape and is used. The durability is consequently improved without depending on environment.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium such as a magnetic tape having a magnetic recording layer made of a ferromagnetic metal thin film suitable for high-density magnetic recording.

BACKGROUND OF THE INVENTION Conventionally, magnetic tapes widely used in practical use are γ-Fe203. C'o doped γ-Fe203
．． A ferromagnetic metal such as CrO2 or iron or an alloy fine powder magnetic material is dispersed in an organic binder such as vinyl chloride/pyro-acidate copolymer, styrene-butadiene copolymer, epoxy resin, etc. to form a polymer film, etc. This is a coated magnetic layer that is coated and dried on a substrate.

In recent years, as the demand for high-density recording has increased, there are great expectations that it can provide an excellent signal-to-noise ratio (S/N) in the high-density area.
So-called metal thin film magnetic recording media, which have a ferromagnetic metal thin film layer as the magnetic recording layer, have attracted attention, and efforts are being made to put them into practical use [for example, journal: I.E.I.
Transactions on Magnetics (IEE)
ETransactions on Magnetic
s) Vow, MAG-20, Kei 6,669-6
74 (1984) The main objective of the improvement of such magnetic recording media is to improve the durability of the magnetic recording layer while maintaining excellent electromagnetic conversion characteristics.

Co-P, Co-N used as magnetic recording layer
A method of forming a protective film on a ferromagnetic metal thin film such as i-0 or Co-Or film to reduce friction with the mechanical material of the magnetic head or traveling system [for example, JP-A-62-16370
7, Japanese Patent Application Laid-open No. 69-171026], or by providing fine irregularities on a polymer film and providing a ferromagnetic thin film on the surface, the actual contact area is reduced and the abrasion resistance and running properties are improved. It has been proposed to improve the performance [for example, JP-A-56-10455, JP-A-59-12163.
See Publication No. 1].

FIG. 2 shows one example of this, in which a ferromagnetic metal thin film layer 2 is formed on a polymer film 1 by oblique vapor deposition, as disclosed in Japanese Patent Application Laid-open No. 59-154641, and then plasma A polymer film 3 is provided, a lubricant layer 4 is provided thereon, and a back coat layer 6 is provided on the other surface of the polymer film 1, and the plasma polymerized layer has a density of 1.4 or more and a thickness of 20 to 20.
It has been shown that when the conditions of 270 people are satisfied, improvements are seen in the still characteristics at 23°C and 65% RH, and the rust prevention effect at 60'080% RH and one week.

Problems to be Solved by the Invention However, in the above configuration, when the magnetic head is alloyed, it is difficult to ensure durability in various practical modes by simply selecting the type of lubricant and the type of plasma polymerized film. It had the problem that it could not be done. Particularly in short wavelength recording where spacing loss has a large effect, the plasma polymerized film preferably has a thickness of 100 Å or less.

In view of the above-mentioned problems, the present invention provides that even if an alloy head is used,
The present invention provides a durable magnetic recording medium with low spacing loss.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention is constructed by sequentially laminating a thin film, a plasma polymerized film, and a lubricant layer on both sides of a polymer film. is made of a ferromagnetic metal thin film.

Effects The present invention has the above-described configuration, and even when used in a tape-like manner, the lubricant is present in almost the same amount on either surface, so the load of the alloy head on the plasma polymerized film is always alleviated. Therefore, durability is improved regardless of the environment.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 is an enlarged sectional view of an embodiment of the present invention as a magnetic tape.

In FIG. 1, 6 is a polymer film made of polyethylene terephthalate film having a thickness of 8.6 μm, and its surface roughness is 600 μm on average and 300 μm thick.

7 is a ferromagnetic metal thin film, which has a thickness of 1000 mm.
o-Ni-0 film, Co-Ni (Ni; 20 w
t%) was obliquely evaporated in oxygen at I x 10-5 Torr with a minimum incident angle of 44 degrees, and the coercive force was 1200.
(Oe).

08 is a thin film in which this film was formed on a surface with an average roughness of 60 mm. This was a CaO film with a thickness of 800 mm on a surface with an average roughness of 300 mm, and was formed by high-frequency sputtering.

No. 9.10 is a plasma polymerized membrane, which is formed by generating a glow discharge while introducing monomer vapor, and passing through the glow discharge through the film provided with the above-mentioned thin film. The monomer used was cycloC4F8, and the glow discharge was 0.
．． A high frequency of 10 KHz at 14 Torr was used.

The thickness of the plasma polymerized films 9 and 10 is 19.01.12 is a stearic acid film which is a lubricant layer, which was formed by vacuum evaporation using 45 people on average.

As a comparative example, 7.9.11 had the same configuration on the polyethylene terephthalate film described above, and 8.10.1
A sample was prepared in which 2 was replaced with a back coat layer.

The back coat layer is carbon instead of urethane resin.

They each had 26% by weight of calcium carbide added, had a thickness of 0.7 μm, and had an average roughness of 330 mm.

Both the above examples and comparative examples were used as 100 m long magnetic tapes with an 8-pin width, which were placed in cassettes, and their performances were compared using a prototype 8-tap video system.

Output was measured at five locations approximately every 15 m out of a 100 m length for 10 minutes in a still state. In addition, regeneration was performed during normal driving. At this time, dropout was also measured.

The alloy head has a ribbon-shaped structure in which an amorphous alloy is sandwiched between ferrite, and the gap length is 0.
It is 25 μm.

Recording wavelength is 0.76μm, reproduction output is relative value (dB)
It was expressed as Dropout is 15μ.

-1 edB or more, expressed in number per hour.

The embodiment of the present invention is 6°C 15°RH, 20°C 66%
In both RH and 40'085%RH environments, the still playback output for 10 minutes is within -1dB, and the playback output during normal driving is within -2dB, and the dropout is 30~30%.
It was stable at 60 pieces/kaku, while the comparative example had 20 pieces/kaku.
"Still playback output is -3d in environments other than 065%RH.
The normal playback output is -2dB to -4.
dB, and the dropout showed an abnormal value at the tape position where the still was performed (1700 to 3620 pieces/dragon)
.

In the product of this invention, both sides of the tape are made of plasma polymerized film and have the same surface, so even if the lubricant is partially reduced due to running or stills, when it is wound, it will be in an equilibrium state due to transfer and the amount will be approximately the same. In the conventional example, since the two surfaces have different properties, the amount of lubricant transferred depends on the environment and the durability is insufficient.

In obtaining the above effects, polyethylene terephthalate film, polyethylene naphthalate.

It may be replaced with polyamide, polyimide, polycarbonate, etc.

As the ferromagnetic metal thin film, instead of Co-Ni-0, Go, Fe, Co-Cr, Go-0,
Go-Ni.

Co-Ti, Co-W, Co-Mo,
Go-Ta, Go-Pt, Go-P, Co-M
It may be nLP, Co-Zr-Nb, etc., or it may be a laminate of either of these and a base layer depending on the case.

The other thin film is another oxide film, nitride film, or metal.

Any alloy etc. may be used.

Compounds that can be used for plasma polymerization include methane,
Ethane, propane, butane, hexane.

Aliphatic saturated hydrocarbons such as octane, aliphatic unsaturated hydrocarbons such as ethylene, propylene, and hexane.

Aromatic hydrocarbons such as benzene, toluene, xylene, and styrene, fluoromethane, and difluoromethane.

Trifluoromethane, tetrafluoromethane, difluoroethane, tetrafluoroethylene, hexafluoropropylene,
Saturated or unsaturated halogen compounds such as tetrafluorosilane and tetrachloroethane, alcohols, ketones,
It is a mixture of ethers, fatty acids, etc.

Fatty acids can be used as lubricants.

Metal 1 soap, fatty acid amide, fatty acid ester.

Mineral oil, animal and vegetable oils such as whale oil, higher alcohols, silicone oils, fluorocarbons, etc. alone or in combination;
Composite 2 Synthesized, metamorphosed, etc. 0 Effects of the Invention As described above, the present invention provides sufficient durability in various environments even for the use of alloy heads, which are important for increasing the density of magnetic recording. This provides excellent effects such as the ability to obtain a magnetic recording medium useful for magnetic tapes with high properties.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a conventional magnetic tape. 6...Polymer film, 7...Ferromagnetic metal thin film, 8...Thin film, 9,1o...
Plasma polymerized film, 11°12...Lubricant layer. Name of agent: Patent attorney Toshio Nakao and 1 other person
Figure 6 ------- Body 1 Child Film 7
Machiusuki Mg--E squad monthly calculation

Claims (1)

[Claims] A magnetic recording medium characterized in that a thin film, a plasma polymerized film, and a lubricant layer are laminated on both sides of a polymer film, and at least one of the thin films is made of a ferromagnetic metal thin film.