JPS62124623A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide good runnability and durability to a titled medium by providing a thin ferromagnetic metallic film and phthalocyanine compd. as an intermediate layer on a nonmagnetic substrate and further laminating a lubricating layer contg. a specific compd. thereon. CONSTITUTION:This recording medium is constituted of the nonmagnetic substrate 1, the thin ferromagnetic metallic film 2, the intermediate layer 3 provided with the phthalocyanine compd. and the lubricating layer 4 contg. at least one kind of the compd. selected from the group consisting of a perfluorocarboxylic acid, perfluoropolyether, thiol and thioglyoclic acid. The perfluorocarboxylic acid is expressed by the general formula (A) where Rf has a fluorohydrocarbon chain of 6-18C. The perfluoropolyether is expressed by the general formula (B) where the degree (n) of polymn. has 10-60 value. The thiol is expressed by the general formula (C) and the thioglycolic acid is expressed by the general formula (D) and is the compd. of which R has a hydrocarbon chain of 12-24C. The recording medium having the excellent lubricity, running stability and wear resistance is thus provided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application Page 3 The present invention relates to a high recording density magnetic recording medium used in the information industry and the like.

Conventional technology Conventional, 7 Fe20a, Go-containing - Fe203
．． So-called coated magnetic recording media have been developed in which ferromagnetic powder such as CrO2 is dispersed in an organic binder and coated on a non-magnetic support.
Currently, magnetic recording media in which a ferromagnetic metal thin film is formed on a nonmagnetic support by plating, sputtering, vacuum evaporation, ion blating, or the like are being actively researched.

However, magnetic recording media using ferromagnetic metal thin films produced by the above method have problems in friction and wear resistance.

In other words, magnetic recording media record magnetic signals.

During the reproduction process, it is in a state of high-speed relative motion with the magnetic head, etc., so contact with the magnetic head, etc. may cause friction that may cause unstable running, or wear and tear will eventually occur if it is run for a long time. This will cause a significant drop in output. Therefore, smooth running performance and durability are strongly desired for magnetic recording media.

For this reason, various proposals have been made to modify the ferromagnetic metal thin film or provide a lubricant layer. Publication No. 60-93638 is an example of these.

Problems to be Solved by the Invention In these cases, although there is an improvement in the lubricity at the initial stage, the protective film peels off or adheres during long-term running, so it is not sufficient.

Therefore, in view of this point, an object of the present invention is to provide a magnetic recording medium with excellent lubricity, running stability, and wear resistance.

Means for Solving the Problems A phthalocyanine compound is provided as an intermediate layer on the upper surface of a ferromagnetic metal thin film provided on a nonmagnetic substrate, and furthermore, perfluorocarboxylic acid, perfluoropolyether, thiol, and thiol are provided on the upper surface of the phthalocyanine compound. The effect of laminating a lubricating layer containing at least one type of six vane compounds selected from the group consisting of glycolic acid provides the friction and abrasion resistant effects of the intermediate layer, and the low friction property of the lubricating layer. With the addition of these effects, a magnetic recording medium with low peeling, good runnability, and excellent durability can be obtained.

This is thought to be because the polar groups of the compound forming the lubricating layer are strongly bonded to the phthalocyanine compound forming the intermediate layer, resulting in sustained lubricity.

Embodiment FIG. 1 is a sectional view of a magnetic recording medium of the present invention. In the figure, 1 is a nonmagnetic substrate, 2 is a ferromagnetic metal thin film, 3 is an intermediate layer with a phthalocyanine compound, and 4 is selected from the group consisting of perfluorocarboxylic acid, perfluoropolyether, thiol, and thioglycolic acid. A lubricating layer containing at least one compound.

Examples of the non-magnetic substrate 1 that can be used in the magnetic recording medium according to the present invention include polyvinyl chloride, polyacetate cell 6 page loin, polyethylene terephthalate, polyethylene,
There are films, plates, etc. made of well-known materials such as polymeric materials such as polypropylene, polycarbonate, polyamide, polyimide, and polysulfone, nonmagnetic metal materials, and ceramic materials such as glass and porcelain.

Further, as the ferromagnetic material forming the ferromagnetic metal thin film 2,
Known materials can be used, for example one or more metals selected from iron, cobalt, nickel, or these and other metals such as manganese, chromium.

There are alloys that combine titanium, phosphorus, yttrium, samarium, bismuth, etc., and there are also oxides of the above-mentioned gold layer.

The ferromagnetic metal thin film 2 is formed and spread on the non-magnetic substrate 1 using a vacuum evaporation method or a sputtering method.

It can be formed by any method such as ion blating method or Meriki method.

The phthalocyanine compound forming the intermediate layer 3 is metal-free or Cu, Co, Ni, Mq, Cr.
.

Zn, Fe, V, Mn, Pb, Sn, Ca, Na, Be
1-47 Page 2 It is a complex compound containing a valent metal. Due to their chemical structure, these have low shear core force and excellent friction and wear resistance. And even better, these are heat resistant,
It has good environmental resistance due to its excellent chemical stability.

The compound forming the lubricating layer 4 is represented by the general formula Rf-CO○H, where Rf is a perfluorocarboxylic acid having a hydrogen oxide chain having 6 to 18 carbon atoms, such as perfluorolauric acid, perfluoromyristin, etc. acids, perfluoropalmitic acid, perfluorostearic acid, perfluorocapric acid, perfluorocaprylic acid, and the like.

The perfluoropolyether is preferably represented by the general formula 0% and has a degree of polymerization n of 10 to 60, that is, a molecular weight of approximately 180 to 1000.

Thiol is represented by the general formula thioglycolic acid, and R is a compound having a hydrocarbon chain having 12 to 24 carbon atoms, such as p-nonadecylthiophenol, p-stearylthiophenol. .

p-stearylphenylthioglycolic acid, p-laurylphenylthioglycolic acid + P-1' lycosanyl phenylthioglycolic acid, p-tetracosanylthiophenol, p-pentadecylthiophenol or p-tridecylthiophenol, etc. can be mentioned. As described in the Examples below, while the fluorinated hydrocarbon chain or hydrocarbon chain exhibits good lubricity, the intermediate layer has a carboxylic acid group, thiol group, or thioglycolic acid group at the molecular end. Because it is strongly bonded to the phthalocyanine compound, there is little peeling off due to sliding of the magnetic head, etc., and the low friction function is maintained, resulting in a magnetic recording medium with excellent running stability and good wear resistance.

9 Vane The method for using it is to use the perfluorocarboxylic acid described above.

At least one compound selected from the group consisting of perfluoropolyether, thiol, and thioglycolic acid is used.

In addition, if the number of carbon atoms in these fluorinated hydrocarbon chains or hydrocarbon chains is 5 or less for perfluorocarboxylic acid and 11 or less for thiol or thioglycolic acid, the lubricity may decrease due to lower molecular weight. If the number of carbon atoms is 19 or more in the former case and 25 or more in the latter case, it will not only be expensive and difficult to obtain, but also have poor lubricity. Since this is not so expected, perfluorocarboxylic acids having 6 to 18 carbon atoms in a fluorinated hydrocarbon chain are preferred, and thiols or thioglycolic acids having 12 to 24 carbon atoms in a hydrocarbon chain are preferred. Similarly, if n is less than 9, perfluoropolyether is highly volatile and the lubricating function cannot be expected to last.If n is more than 61, sample dilution and coating will be difficult, so n is 10. ~6o is preferred.

The formation of the intermediate layer and lubricant layer as described above can be easily achieved by combining with a normal dry method such as vapor deposition, or a wet method such as coating, spin cord, or LB method, and the thickness of these layers is 50-4008 is preferable. Because, 5
If it is less than 08 Å, holes, holes, etc. are likely to occur and sufficient lubricity cannot be obtained, while if it is more than 400 Å, the signal output will decrease due to spacing loss.

A specific example will be explained below.

Example 1 A ferromagnetic metal thin film of Co-Cr (elemental composition ratio, Co:Cr=9:1) with a thickness of 1300 mm was created on a polyimide film substrate with a film thickness of 45 μm using a continuous vapor deposition method. It was designated as sample f■.

Copper phthalocyanine (hereinafter abbreviated as CuPc) was deposited on this to a thickness of approximately 160 mm to form an intermediate layer (sample f
(2) Furthermore, a lubricating layer was formed using perfluorolauric acid to a thickness of approximately 200 mm using the same method (sample f (2)).

For comparison, a sample (sample 2) was prepared in which only the lubricating layer was directly formed on the ferromagnetic metal thin film. The results of these evaluations for 11 bases are shown in FIG.

For evaluation, the film thickness was determined by SEM or nip measurement, and the dynamic friction coefficient was measured using a DF, PM type friction coefficient meter manufactured by Kyowa Interface Science Co., Ltd. at a load of P-15qf and a speed of v = 1.3 u.
/ s, he,, a steel ball with a diameter of 4M (SUJ
2) was tested at room temperature.

According to Figure 2, sample f■ has a dynamic friction coefficient μ from the beginning.
k is high and continues to rise with the number of runs (Pass),
At less than 1 o□Pa5s, the surface of the medium was seriously damaged, making measurement itself impossible.

On the other hand, sample I■ has a small value of μ from the beginning and remains friction resistant even after 5 seconds at 20 OPa.

Although it has excellent wear resistance, it has high dynamic friction characteristics because μ does not go below 0.2. On the other hand, sample Akira ■ had a small μk and excellent lubricity at the beginning, but the value increased from around 100 Pas, and a phenomenon similar to peeling occurred, resulting in a lack of durability.

On the other hand, sample engraved (2) exhibited good runnability and durability, with μk being small even at the initial stage, and this tendency persisting even after 20QPass, and no abnormalities were observed on the sample surface.

From the above, it has been found that a phthalocyanine compound such as CuPc is provided as an intermediate layer on the upper surface of a ferromagnetic metal thin film, and a perfluorocarboxylic acid such as perfluorolauric acid is further formed on the upper surface as a lubricating layer. It can be seen that the magnetic recording medium obtained by the method can be realized as a recording medium with improved friction resistance and excellent wear resistance.Example 2 Co-C
A sample was prepared using R film with a thickness of 1000 layers, and an intermediate layer of nickel phthalocyanine (NiPc) was formed on this with a thickness of about 260 layers.

A solution of perfluoropolyether (n = 30) diluted to about 0.5 wt% with trifluorotrichloroethane was added to this using a spin code (1000 rpm for 3 seconds + 150 O
r pm for 20 seconds).
).

13 Begemata, p-tlJdecylthiophenol, and p-dodecylphenylthioglycolic acid compounds, respectively,
A solution adjusted to 0.1 wt% with chloroform solution was spin-coded under the same conditions as above (7)/l/4
, ■). The thickness of the lubricating layer was 210, 180, and 175 mm for samples A to A, respectively.

These were prepared in the same manner as in Example 1, p-5qf, -1゜mr
b/s, the head is a steel ball with a diameter of 12 (SUJ'2
) was tested. The results are shown in Table 1.

Table 1 As is clear from Table 1, Samples S to ■ had good characteristics such that μk was 0.2 or less even after 200 passes, and there were almost no scratches on the sample surface. ing.

Page 14 Therefore, a magnetic recording medium composed of an intermediate layer of a phthalocyanine compound and a perfluoropolyether, thiol, or thioglycolic acid compound as a lubricating layer has stable running performance and improved durability. It can be seen that it is a medium.

Example 3 Co and Cr on a polyimide substrate with a film thickness of 35 μm.

A ferromagnetic metal thin film with a composition of Ni, etc., to a thickness of 1000 to 20 ㎜ was formed by vapor deposition, and as described in Table 2, an intermediate layer and a lubricant layer were formed by vapor deposition and spin-coding to prepare a sample. Created (Sample 5■~@). These evaluation results are shown in Table 2. The evaluation conditions are p-20qf, ■=
1.0M/B, the head is a steel ball with a diameter of 3 (SUJ 1)
It is. In addition, the surface oxidation of the ferromagnetic metal thin film is caused by Co, Cr, etc.
, Ni, etc. are vapor-deposited by simultaneously injecting oxygen, and the thickness is 16 cm above the ferromagnetic metal thin film layer. It shows that there is.

As shown above, the sample flat ■~@ exhibited low friction properties of 74k=0, 11~0.19 in the running test after 2o○ bus or more. The surface condition of the sample after running was either intact or only slightly scratched, indicating good wear resistance.

Therefore, from these reasons, a phthalocyanine compound is provided as an intermediate layer on a ferromagnetic metal thin film, and a perfluorocarboxylic acid having a fluorinated hydrocarbon chain having 6 to 180 carbon atoms or a polymerization degree n= Lubricity and running properties can be improved by laminating one or more compounds selected from 10 to 6o perfluoropolyether, thiol having a hydrocarbon chain of 12 to 24 carbon atoms, or thioglycolic acid. A magnetic recording medium with excellent stability and durability can be obtained. At this time, each film thickness is
Overall, the effect is exhibited in the range of 50 to 4008, which shows that it can be realized as an excellent recording medium without spacing loss. A magnetic recording medium with excellent wear resistance can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a magnetic recording medium according to an embodiment of the present invention, and FIG. 2 is a graph showing changes over time in the coefficient of dynamic friction of various recording media. DESCRIPTION OF SYMBOLS 1...Nonmagnetic substrate, 2...Ferromagnetic metal thin film, 3...Intermediate layer, 4...Lubricating layer. Name of agent Patent attorney Toshio Nakao and 1 other person E-Ichipaku Ippon Seiben 4th 4th 4-SifA Karidai 2 Zumarutake Circular CPvδ)

Claims (6)

[Claims] (1) On the top surface of the ferromagnetic metal thin film provided on the nonmagnetic substrate,
A phthalocyanine compound is provided as an intermediate layer, and further,
A magnetic recording medium characterized in that a lubricating layer containing at least one compound selected from the group consisting of perfluorocarboxylic acid, perfluoropolyether, thiol, and thioglycolic acid is laminated on the upper surface thereof. (2) Claim 1, wherein the perfluorocarboxylic acid is represented by the general formula (A), and R_f-COOH...(A) R_f is a fluorinated hydrocarbon chain having 6 to 18 carbon atoms. The magnetic recording medium described. (3) The perfluoropolyether has the general formula (B)
The magnetic recording medium according to claim 1, wherein n has a value of 10 to 60. (4) The thiol is represented by the general formula (C), ▲ mathematical formula,
There are chemical formulas, tables, etc.▼...(C) The magnetic recording medium according to claim 1, which has a hydrocarbon chain having 12 to 24 carbon atoms. (5) The thiol is represented by the general formula (D), and there are mathematical formulas, chemical formulas, tables, etc.▼...(D) Claim No. 1, wherein R is a hydrocarbon chain having 12 to 24 carbon atoms. The magnetic recording medium according to item 1. (6) The magnetic recording medium according to claim 1, wherein the ferromagnetic metal thin film has been subjected to surface oxidation treatment.