JPS58189834A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve traveling durability remarkably, by adsorbing a rust inhibitor layer beforehand on a ferromagnetic thin metallic film and forming a lubricant layer of polytetrafluoroethylene having a low degree of polymn. thereon. CONSTITUTION:An adsorbent layer for a rust inhibitor is provided on the surface of a ferromagnetic thin metallic film formed on a nonmagnetic substrate, and a lubricant layer of polytetrafluoroethylene having a low degree of polymn. is provided on the adsorbent layer. Rust inhibitors used for general metals are usable for the ferromagnetic thin metallic film wherein oxygen is not particularly contained and there are basic nitrogen compds., such as alkyl amine, fatty acid of alkyl amine, etc. as the example thereof. The lubricant layer of polytetrafluoroethylene having a low mol.wt. is formed on the adsorbent layer for the rust inhibitor. The polytetrafluoroethylene having <=10,000mol.wt. is preferable as the polytetrafluoroethylene having a low mol.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a ferromagnetic metal thin film magnetic recording medium with improved running stability and durability. Alternatively, a 10,000-thick gold thin film with oxygen added to these is vacuum evaporated or sputter-linked.

A ferromagnetic metal thin film type magnetic recording medium formed on a weir plate F2 made of a polymer film such as a polyester film or a polyimide film, or a non-magnetic metal thin plate using a film forming method in vacuum such as ion blasting is different from the conventional one. It is possible to dramatically improve the recording density compared to coating-type magnetic recording media, but in order to achieve this high density, it is necessary to reduce the gap between the magnetic heads and to improve the surface of the magnetic recording medium. Wm
Is it necessary to reduce Spene Cross as much as possible by turning it into a monster? Specifically, the value of the spacer is required to be 5005° or more, and preferably 300λ or less.
There is. By finely controlling the surface shape of the non-recording medium in 6, the head touch 1, 1 line, 1 line, 1- is considerably thinned out, but essentially, the contact between -\ throat and medium (
[It is difficult to reduce the h1 product to the human rIJ, and the tendency to make the ll7-coefficient more sensitive is difficult to avoid.[8]

-Also, in general (・'C ferromagnetic metals are prone to corrosion in humidity, so to avoid this, rationalization of the magnetic layer,
In addition to oxygen-containing modification, it has been proposed to use rust preventive agents. Rust preventive agents are usually compounds containing specific polar groups that bond with ferromagnetic ions. Therefore, it is possible to prevent rust from occurring once a month by adsorbing it on a strong magnetic thin film, or it has almost no effect on head touch and running, and if it is allowed to adhere excessively. head 1
It has become clear that this method has the disadvantage of causing jams.

The application of various lubricants has been proposed for the purpose of increasing the coefficient of friction between curved blades and magnetic recording media. However, when this material is applied directly to a ferromagnetic l'V metal thin film F as a lubricant layer, it has no corrosion resistance in high humidity (in this case,
! I did not show the imperial effect, and also like this (Thus? (I et al.)
When Luru1 miki recording medium is put on a VTR chip
It became clear that the predictions regarding the durability of the L row did not go as expected. In particular, the latter reason and the low polymerization degree polytetrafluoroethylene ferromagnetic gold 10,000,'i
This was thought to be due to the weak adhesion strength with lI'a.

In addition to the conclusion of the studies conducted by the present inventors, there is a case in which a rust preventive layer is adsorbed in advance on a 10,000-thick ferromagnetic gold thin film, and a 1f3 low-polymerized polytetrafluoroethylene lubricant layer is formed on the layer. It has become clear that the running durability is 1 < 4.

That is, in the present invention, an adsorption layer of a rust preventive agent is provided on the surface of a ferromagnetic metal thin film formed on a non-magnetic substrate, and a lubricant layer of low-strength polyteketofluoroethylene is provided on the adsorption layer). The present invention relates to a magnetic recording medium characterized in that it is provided with.

1. Details of the present invention by component +! , with 1llVC.

Polyester film is used as a non-linear substrate.

Plastic films such as polyimide films.

Aluminum roots, stainless steel temporary metal plates, glass plates.

Teruiso-quality temporary materials such as ceramic temporary materials are used.

The surface properties of thin-film magnetic recording media are very small, about 0.1 to 0.6/1 m of the magnetic layer thickness, so JI
';#! , the table [a1 has a large degree of dependence on the shape. Therefore, the surface shape described in JP-A-53-116115, JP-A-56-16937, and JP-A-57-37719 is not finely controlled. It is particularly desirable as a substrate.

Strong metal thin films include iron, cobalt, nickel,
– or their alloys by vacuum evaporation, ion bracing/
directly onto the substrate by sputtering, etc., or
A thin film formed through a non-magnetic base thin film of aluminum, titanium, chromium, etc., or a thin film in which the non-magnetic thin film described in 1.1- is inserted into a ferromagnetic thin lIQ as a 1111 Hibarator. etc. can be used, and −)
, r, I-@ Those with improved strength, corrosion resistance, magnetic properties, etc. are particularly desirable. As for the ancient times, the
No. 23208, JP-A-53-42010, JP-A-56-15014, JP-A-67-37719
1).

As a rust preventive agent that forms the antifouling agent absorption layer, a ferromagnetic metal thin film (ζχtL-71) that does not contain oxygen is used.
0-1, - Rust preventive agent used for general metals)
1] Examples include alkyl amines,
Alkylamine diphosphate (r----'), alkylthi subphosphate-1,
.

Alkylhytron 1 [phase] phosphate esters Phosphides such as oyohyophosphite 2 Ishiura sulfonate, mahogany acid sulfonate, cinonyl nanocrystalline acid, sulfonate such as /sulfonate, norbitan mono-A ureate,
There are 4-1f esters such as methyl ester of iTf8m, 4-1f constant esters such as methyl ester of iTf8m, specific carbonic acid derivatives such as α-mercaptostearic acid, chlorhexyl ammonium nitrite, and diisopropyl. The use of so-called volatile rust inhibitors such as ammonium nitrite and cyclohexylamine calmate is also prohibited. For these examples, see e.g.
-Metal Omagari Technology Handbook-1 New Edition, edited by Kinsei Surface Technology Association (published in 1138, published in 1138, currently in circulation, 11 years ago - a certain newspaper company) 1
It is described on pages 417-1439.

-Also, for ferromagnetic metal thin films containing oxygen, it is used for general metals as described above! 1- Be sure to use a rust preventive agent.

It cannot be said that these anti-corrosion agents are also suitable; in fact, applying these anti-rust agents may actually promote corrosion, so in addition to the well-known anti-rust agent 41, it is recommended that they be applied to ferromagnetic thin films containing oxygen. It is important that things be written in a single historical format. These L]-ru, quinones, nitrone compounds, oxime compounds, etc.
These are shown in more detail as follows.

Dihydric phenols include pure phenols such as hydroquinone, resorcinol, and catechol, as well as alkylamino, nitro, and nitroso.

Halogen-substituted products, such as 2-methyl-itroquinone, 4-methylresorcinol, 5-methyJL resorcinol, 4-methylpyrocatechol, 2.5-methylhydroquinone, 4,6-nomethylresorcinol, 2
, 5-dimethylresolunol, 2-isopropyl-5
-Methyl itoquino7, 2-tert-butylno\itoquinone, 2゜5-tert-butylhydroquinone, 4-tert-butylcatechol, 2-
amylsol/nor, 2-nitroresol 7-ol, 2,
6-chlorohydroquinone, %.

Diallyl ketones include benzophenone and its
Refers to A4 body, for example, benzopheno/.

Alkyl substituted products such as 4-methylbenzophenone, 3-methylbe/sophenone, 3,4-dimethylbenzophenone, 4゜41-dimethylbenzophenone, 3,4'-dimethylbenzophenone, 4-ethylbenzophenone, and 4-hydroxybenzophenone.

4.4'--Hydroxybe/siphenon, 2,3°4
- ) Hydroxy such as IJ hydrobe/siphenon, 2,4-hydroxybe/siphenon, 2.2', 6.6'-tetrahydrobenzophenone, 2.3', 4.4', 6-be/tahitoloki/be/siphenon, etc. Benz Feno/
4-aminobe/zonoenone, aminobe/zononenes such as 4.41-aminobenzophenone, or 2-aminobe/zonoenone;
Henzinoenones with more than one substituent, e.g.
4-methoxy-2-hydroquinobenzophenone, 2.2
It refers to '-dihydroquine-4,4'-dimethquine benzophenone, 2°6-7hydroxy-4-methoxybenzophenone, etc.

Alkylphenol refers to an alkyl substituent with a -valent phenol, such as 0-cresol, m-cresol + p-J resol, 0-ethylphenol, m-ethylphenol, p-ethylphenol, 2.3- Dimethylphenol - Methylphenol, 2,6-dimethylphenol, 3,4-dimethylphenol, 3,6-
methylenol, 2,4.6-trimethylpheno.

2,4.5-4-limethyl 7-methylphenol, 5-inopropyl-2-methylphenol, 2-ino70-kubiru-
5-methylphenol, p-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, 4,4'-methylenehis-2.

6-7-tert-butylphenol, 2.6-
/Methyl-4-tert-methylphenol tert
-amyl-4-methylphenol, 2-methyl-4,6
- Sorter t-butylphenol.

2,4.6-) tertbutylpheno-iL,',
There is q.

Naphthol lees and +=. -t. , α-naphthol, β~
f-,/toll, 1, 2-naphthalenediol, 1
, 4.

Pure naphthols such as 5-naphthalenetriol, 1,2,5.8-naphthalenetetraol, and nitro,
Nitroso-, amino-, norogeno-substituted naphthol m, such as 1-chloro-2-naphthol, 2,4-cyclo-1-naphthol, 1-nitro-2-naphthol, 1,
6-sinitro-2-naphthol, 1-nitrono-2-naphthol, 2-nitrone-1-naphthol, 1-amino-2-naphthol.

Quinones include P-benzoquino/, 0-benzoquinonoa 1,2-naphthoquino 7, 1,4-nandoquino, 2,6-
Naftquine, anthraquine, 9-10-phenanothrenequinone, cifue, tsuquinone, etc. (quino/without θ substituent,
Methylquinones such as methyl-P-benzoquinone, 2,-1dimethyl-P-benzoquinone/, 2-methyl-1,4-nathoquinone, 2-methylanthraquino/, 2,6-cyhydroquinone, P-penshanone, 5-hydroxy-1.

4-Nuttoquinone, 2,3-dihydroxydi 1.

4-Nuttoquinone, 6,8-dihydroxydi 1.

4-nattoquinone, 2-hydroxyanthraquino 7,1
, 2-dihydroxyanthraquinone, 1,2,3~trihydrokey/anthraquinone l' + 2+4-trihydroxyanthraquinone, 1,2,5-trihydroxyanthraquinone, 1,2,6-trihydroxyanthraquinone t1,2+71''dihydroxyanthraquinone 2 7 hydroxyquinones such as 2-amino-anthraquinone, aminoquinones such as 1,2-diaminoanthraquinone, nitroquinones such as 1-nitroanthraquinone, 1,5-dinitroanthraquinoneffl+2+6-dichloro-P-benzoquinone, tetrachloro-P -Benzoquinone, tetraglomo-P-benzoquinone, etc. Logenoquinones, or quinones with two or more substituents, such as 2,5-dichloro-3,6-cyhydroxy-P-benzoquino/, 1-methyl- 2-hydroxy-1
, 4-naphthoquinone, etc.

and nitrosonaphthol-based organic compounds. Specifically, 1-nitrono-2-naphthol, 2-nitrono-1-naphthol, 1-nido sodium salt and Toroso R salt), 4-nitroso-2-methoxy-1-7enol, 4-nitroso-2-1 -)-t-thi-1-phenol, 4-nitronecarvacrol, 6-nitrone-〇-
Cresol.

4-nitrone-m-cresol, 0-nitronephenol, 2-nitroneresorcin, 4-nitrosoresorcin, 2-nitroneresorcin monomethyl ether, N-nitrone phenylhydroxylamine ammonium salt (cuperon), P-nitronephenol, 2 -nitroso-1
It refers to nitroso-4-sulfonic acid, 5-nitroso-8-quinolitool, and the like.

The oxime compound refers to benzyloxime, glyoxime, benzaldoxime, benzamide oxime, α-benzoin oxime, acetophenone oxime, benzophenone oxime, dimethylglyoxime, salicylaldoxime, and the like.

Methods for providing an adsorption layer of a rust preventive agent on the surface of a ferromagnetic metal thin film include diluting the rust preventive agent with a solvent and coating it thinly on the ferromagnetic metal thin film, or applying the rust preventive agent in the air or in an inert gas. Alternatively, it can be carried out by vaporizing it in a vacuum and applying the vapor to the ferromagnetic metal surface. In this case, the rust inhibitor may be a single substance or a mixture of multiple types. It is also possible to perform appropriate heat treatment during or after adsorption to ensure complete adsorption of the rust preventive agent. Excessive adhering rust inhibitor can also be removed by cleaning with a solvent. Normally, rust preventives are strongly adsorbed to the surface of a ferromagnetic metal thin film in a state of chemical adsorption or a state close to chemical adsorption, so they are not removed by solvent cleaning. This can be inferred from the fact that a sufficient rust prevention effect can be obtained even after cleaning with a solvent, and can also be determined by chemical shift measurement using X-ray light-based electrochemical shift analysis (ESCA).

In the present invention, it is desirable that the rust preventive agent on the ferromagnetic metal thin film be present in a slightly excessive amount in addition to the adsorption layer forming components. This means that even if a part of the ferromagnetic thin film is damaged by wear, cracks, etc. while the magnetic recording medium is running, the rust preventive agent that is present in excess will newly adsorb to that part. This is because corrosion resistance can be improved. The appropriate amount of the rust preventive applied to the ferromagnetic metal thin film (including the adsorption layer) is 1 to 50 m9/m', more preferably 6 to 2 cmg/'.

On the rust preventive adsorption layer, a low molecular weight lubricant layer of polytetrafluoroethylene is formed. As the low molecular acid polytetrafluoroethylene, those having a molecular acid of 10IOoO or less are preferable, such as DuPont's Paidasox AR1.
Examples include AG-Lub from Asahi Glass Co., Ltd. These are usually in the form of fine particles of low molecular weight polytetrafluoroethylene dispersed in trichlorotrifluoroethane, etc., so they can be further diluted with a similar solvent, applied on the rust preventive adsorption layer, and dried. A lubricant layer is formed.

Low molecular weight FJL polytetrafluoroethylene "8t"
Suitably, t is 1 to 100 mg/m, more preferably 2 to 30 mg/m.

Next, examples of the present invention will be described.

Thickness 10/7m and surface area Rmax - approx. 3o○
A polyester film with corrugated protrusions was placed along the circumferential surface of a cylindrical can, and oxygen gas was introduced at a flow rate of 0.3 N/min in a vacuum of 5 × 10 Torr at 1°, then melted by electron beam heating. Ni alloy (Ni-containing clear 2
0 wt%) by continuous oblique evaporation (low incidence ffJ Ii
A ferromagnetic thin film of 1000% oxygen-containing CoNi is formed on the film (cut by 30° or less).
Sample A) and the vacuum degree 5X10 To
Sample B was prepared in which a CoNi ferromagnetic thin film containing no residual oxygen was formed by vapor deposition without introducing oxygen gas. As a result of measuring oxygen in the film mainly using Auger electron spectroscopy, it was found that the homogeneous element l in the film of sample A was C
For O and N1, those of sample B were less than 1%. Various rust preventives dissolved in ethyl alcohol, acetone, ethyl acetate, toluene, etc. were applied to the surfaces of these samples and dried to form an adsorption layer of the rust preventive agent on the sample surfaces. A lubricant layer made of low molecular weight polytetrafluoroethylene was formed on the surface by applying a solution prepared by diluting AG-Lub (manufactured by Asahi Glass Co., Ltd.) approximately 100 times with trichlorotrifluoroethane and drying it. (The coating amount was adjusted to about 20 mji/m'.) Thereafter, these samples were slit into predetermined lengths to form magnetic tapes. These tape samples were left in an atmosphere at 50°C, 90% R, H, and during this time sample A was taken out every 3 days and sample B was taken out every day and recorded and played back on a video deck to check for clogging. The state of rust occurrence was investigated by observing the surface of the magnetic layer side under a microscope. The results are shown in the table below.

In the following margin, it should be noted that the example described in [) 11 relates to a CoNi magnetic thin film, but this effect is similar to that of a Co thin film, Fe-N
It was similar in i thin film, Fe-Co thin film, etc.

In addition, ferromagnetic thin films containing oxygen are more effective than pure metal thin films;
It can be significantly obtained at a concentration of 3 to 45%.

As is clear from the above, the magnetic recording medium of the present invention has improved overall durability including corrosion resistance, runnability, and head clogging, and has great practical value.

Claims (1)

[Scope of Claims] A ferromagnetic metal thin film formed on a non-magnetic substrate, an adsorption layer of a rust preventive agent provided on the I-side, and said adsorption layer F. Contains one low-polymerized polytetrafluoroethylene in d″I
A magnetic recording medium characterized by an I-layered layer. J