JPH0593194A - Diacylhydrazine lubricant and magnetic recording medium - Google Patents

Abstract

PURPOSE:To provide a diacylhydrazine which is useful in a high-density magnetic recording medium as a functional lubricant excellent in adsorptivity and durability by selecting a specific diacylhydrazine. CONSTITUTION:The title lubricant comprises a diacylhydrazine having fluorinated polyether groups represented by the formula in the side chains.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a functional lubricant used in a high density magnetic recording medium, and relates to a reactive material which is strongly adsorbed to a protective film on the magnetic recording medium by light or heat.

[0002]

2. Description of the Related Art Conventionally, various lubricants have been studied for use in magnetic recording media, especially magnetic disks, and it is known that a fluorine-based polyether derivative is effective (Japanese Patent Laid-Open No. SHO 63-242242). 64-59614, JP-A-1-
131132, JP-A-1-268664). However, recently, as the magnetic recording density of the magnetic disk has become higher, the hardness of the protective film for protecting the disk has improved,
The protective film thickness has been decreasing, and it is observed that the conventionally used lubricants have a poor adsorptivity to these carbon-based protective films and a low durability. In order to solve these problems, a method of applying a lubricant and then irradiating deep UV light has been reported (DAvid D. Save.
rstein, L .; Judy Lin, Langmui
r , 1990, 6 , 1522-1524). However, according to this method, there are problems in that the coating film thickness of the lubricant is small and the durability is poor.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a functional lubricating substance having the above-mentioned problems and having high adsorption and excellent durability.

[0004]

A feature of the present invention is to newly synthesize a diacylhydrazine having a fluorine-based polyether as a side chain as shown below and utilize it as a lubricant.

[0005]

[Chemical 7]

[0006]

[Chemical 8]

[0007]

[Chemical 9]

[0008]

[Chemical 10]

[0009]

[Chemical 11]

[0010]

[Chemical formula 12]

[0011]

[Chemical 13]

[0012]

[Chemical 14]

The molecular weight of the substance used here is 500 to 20.
0000 is desirable, and those having a molecular weight of 2000 to 10,000 are more useful. When the molecular weight is 200 or less, the lubricant tends to scatter during the coating operation and the lubricating effect tends to be low. When the molecular weight is 200 or more, the relative concentration of hydrazine decreases and it becomes difficult to exhibit the adsorptivity.

[0014]

In order to improve the adsorptivity between the lubricant and the protective film for the magnetic recording medium and to provide excellent durability, hydrazide which is a reactive functional group was introduced. This lubricant was dissolved in a solvent and then applied to a magnetic recording medium, and then the magnetic recording medium was irradiated with ultraviolet rays using a 500 W high pressure mercury lamp.
It is considered that this causes the surface of the protective film to react with the hydrazide portion to form a strong bond. Similarly, the same effect was obtained by heating the magnetic recording medium coated with the lubricant.

The lubricant according to the present invention is used in the form of a solution dissolved in a suitable organic solvent. The solvent used in this case is preferably a fluorinated solvent from the viewpoint of solubility, but is not limited thereto.

The coating method of the lubricating substance of the present invention is LB
A method such as a spin coating method, a dipping method, or spin coating with a spinner is possible, and can be appropriately selected. The coating thickness of the lubricant can be adjusted by the coating conditions, the solution concentration, and the subsequent processing conditions.

The above heat treatment is preferably performed at a heating temperature selected from a temperature range of 80 to 250 ° C. for 5 to 60 minutes.

As a magnetic recording medium to which the lubricant of the present invention is applied, there is a magnetic disk coated with a carbon-based protective film, which has the structure shown in FIG.
That is, a base layer (2) such as Ni-P and a magnetic film (3) are sequentially deposited on a substrate (1) such as Al, and a carbon-based protective film (4) is further formed thereon by a sputtering method or plasma C.
It has a structure provided by the VD method. The formation of the carbon-based protective film by the sputtering method means that the magnetic disk is 10 to ⁶ To
Argon gas (gas pressure: 1
0 mTorr) is introduced and the target is graphite. In addition, plasma CVD (Chemi
The cal vapor deposition method is a method of forming a thin film by the reaction of ions or radicals formed by ionization of a source gas or a plasma reaction on a substrate. The protective film formed by this method has the properties of high hardness, high transparency, high resistance, and chemical inertness.

In addition to the above-mentioned magnetic disk, magnetic tape and the like are also included as objects to which the lubricant of the present invention is applied. Further, the present invention can be used not only for magnetic recording media but also for various other devices. After applying the hydrazide-introduced lubricant as described above, it can be strongly adsorbed to the carbon-based protective film on the magnetic recording medium by ultraviolet irradiation or heat treatment, thereby improving the reliability and durability of the magnetic recording medium. I was able to improve.

[0020]

EXAMPLES The present invention will be described below with reference to examples.

Example 1 10.78 g (2.4 mmo) of perfluoropolyethercarboxylic acid (average molecular weight 4500) shown in Chemical formula 13
l) was dissolved in 10 ml of trifluorotrichloroethane, 514 mg (2.5 mmol) of phosphorus pentachloride was added thereto, and the mixture was stirred for 1 hour. Hydrazine monohydrate 126
After adding mg (2.5 mmol), triethylamine 1
ml was added slowly. After stirring for 3 hours, solvent extraction is performed,
It was washed with water and the drying agent MgSO ₄ was added. The desiccant was filtered off and the solvent was distilled off to obtain 7.54 g of the diacylhydrazine of Chemical formula 7.

The boiling point of 100 g of the thus-synthesized compound 7 and 3 g is 100
A 1% by weight solution was prepared by dissolving in 27 g of a fluorine-based solvent at 0 ° C.

A 5-inch diameter magnetic disk covered with a 20 nm sputtered carbon protective film was immersed in the above solution for 10 minutes, and the magnetic disk was taken out and dried. The disk thus coated with the lubricant was irradiated with light of 25 mW and a wavelength of 366 nm for 3 minutes using a 500 W high pressure mercury lamp. This disk was immersed in a fluorine-based solvent having a boiling point of 100 ° C. and irradiated with ultrasonic waves for rinsing. Lubricant film thickness is FT-
When measured using IR, it was highly adsorbed at 10 nm. When a static friction coefficient of this sample was measured by applying a load of 20 g by point contact, a very small value of 0.13 was obtained, which was good. Also, when a wear was measured by a contact start stop (CSS) test at a peripheral speed of 20 m / sec by applying a load of 20 g by point contact, the wear was scarcely observed even after 10,000 measurements.

Example 2 A magnetic disk having a diameter of 5 inches covered with a 20 nm sputtered carbon protective film was dipped in the solution of chemical formula 7 prepared in Example 1 for 10 minutes, and the magnetic disk was taken out and dried. The disk thus coated with the lubricant was heat-treated at 120 ° C. for 30 minutes. After rinsing with a solvent for this sample in the same manner as in Example 1, the film thickness was measured, and a static friction coefficient was measured by applying a load of 20 g by point contact, and further abrasion was measured 10,000 times. The results are summarized in Table 1.

[0025]

[Table 1]

Example 3 A magnetic disk having a diameter of 5 inches covered with a 20 nm thick amorphous carbon protective film provided by a CVD method was immersed in the solution of Chemical formula 7 prepared in Example 1 for 10 minutes, and then the magnetic disk was removed. It was taken out and dried. Using a 500W high pressure mercury lamp, the disk coated with the lubricant was
Ultraviolet irradiation was performed by irradiating with mW of light for 3 minutes. After rinsing the sample with a solvent in the same manner as in Example 1, the film thickness was measured, and a static friction coefficient was measured by applying a load of 20 g by point contact to further measure the abrasion of 10,000 times. The results are summarized in Table 1.

Example 4 A magnetic disk having a diameter of 5 inches covered with a 20 nm-thick amorphous carbon protective film provided by a CVD method was immersed in the solution of chemical formula 7 prepared in Example 1 for 10 minutes, and then the magnetic disk was removed. It was taken out and dried. The disk thus coated with the lubricant was heat-treated at 120 ° C. for 30 minutes. After rinsing the sample with a solvent in the same manner as in Example 1, the film thickness was measured, and a static friction coefficient was measured by applying a load of 20 g by point contact to further measure the abrasion of 10,000 times. The results are summarized in Table 1.

Example 5 The perfluoropolyethercarboxylic acid shown in Chemical formula 14 was converted to a diacylhydrazine by the same operation as in the method shown in Example 1. That is, the perfluoropolyethercarboxylic acid shown in Chemical formula 14 (average molecular weight 350
0) 11.55 g (3.3 mmol) was dissolved in 10 ml of trifluorotrichloroethane, and phosphorus pentachloride 8 was added thereto.
60 mg (4.1 mmol) was added and stirred for 1 hour. 226 mg (4.5 mmol) of hydrazine monohydrate
Was added, and 1 ml of triethylamine was slowly added.
After stirring for 3 hours, solvent extraction, washing with water, and drying agent MgS
O ₄ was added. The desiccant is filtered off and the solvent is distilled off 8.41 g
The diacyl hydrazine of Chemical formula 1 was obtained.

A few g of the compound thus synthesized is used as a boiling point of 100 g.
A 1% by weight solution was prepared by dissolving in 27 g of a fluorine-based solvent at 0 ° C. Corresponding to the method shown in Examples 1 to 4, this solution was applied to a magnetic disk and post-treated,
The results of measuring the lubricant film thickness, static friction coefficient, and wear are summarized in Table 2 as Examples 6 to 9.

[0030]

[Table 2]

Example 10 One of the compounds shown in Chemical formula 9 was synthesized by treating the perfluoropolyethercarboxylic acid shown in Chemical formula 13 with phosphorus pentachloride and then adding, for example, stearic acid hydrazide.

For these series of chemical formulas 9, a 1% by weight solution was prepared by dissolving it in a fluorine-based solvent having a boiling point of 100 ° C., and was applied to a magnetic disk for post-treatment to remove the lubricant film thickness, static friction coefficient, and wear. The measured results are shown in Examples 11 to 1.
4 is summarized in Table 3.

[0033]

[Table 3]

Similarly prepared compounds 10, 11, and 12 were dissolved in a fluorine-based solvent having a boiling point of 100 ° C. to prepare a solution of 1 weight percent, which was applied to a magnetic disk and post-treated to give a film thickness, The results of measuring the static friction coefficient and the wear are shown in Table 4 as Examples 15 to 18 in Table 4.
1 is shown in Table 5 as Examples 19 to 22.
Are summarized in Table 6 as Examples 23 to 26.

[0035]

[Table 4]

[0036]

[Table 5]

[0037]

[Table 6]

Comparative Example Comparative Example 1, a lubricant of perfluoropolyether (Fomblin Z-DOL, manufactured by Montedison Co.) was used at a boiling point of 10
It was dissolved in a fluorine-based solvent at 0 ° C. to prepare a 1 wt% solution. This solution was applied to a magnetic disk protected by a sputter carbon, dried, immersed in the above solvent and irradiated with ultrasonic waves. The results of measuring the lubricant film thickness, the coefficient of static friction, and the wear of this sample are summarized in Table 7.

[0039]

[Table 7]

A magnetic disk was post-treated with the solution shown in Comparative Example 1 in the same manner as in Examples 1 to 4 to measure the lubricant film thickness, static friction coefficient, and wear. Are summarized in Table 7 as ~ 5.

CRYTOX 240AC (manufactured by DuPont) was used instead of the lubricant shown in Comparative Example 1, and Comparative Examples 1 to 5 were used.
The results of the same operations as in Comparative Examples 6 to 10 are summarized in Table 8.

[0042]

[Table 8]

The lubricant shown in Comparative Example 1 was used as Demnum S.
The operation was performed in the same manner as in Comparative Examples 1 to 5 instead of Y-3 (manufactured by Daikin). The results are summarized in Table 9 as Comparative Examples 11 to 15.

[0044]

[Table 9]

As is clear from these results, the diacylhydrazine type lubricant according to the present invention has a film thickness of 8 to 12 n.
m is good, and the coefficient of static friction is as small as 0.15 or less 1
It had excellent adsorbability and durability, and was able to withstand the results of abrasion tests of 10,000 times. On the other hand, the known lubricant did not give good results in terms of film thickness, coefficient of static friction and wear.

[0046]

As described above, the life and reliability of the magnetic recording medium are improved by providing a lubricating substance that reacts with the above-mentioned light and heat and strongly adheres to the magnetic disk coated with the carbon-based protective film. And high density recording was realized.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a magnetic disk used in the present invention.

FIG. 2 is a diagram showing an IR spectrum of Chemical formula 1.

[Explanation of symbols]

1 ... Substrate, 2 ... Underlayer film, 3 ... Magnetic film, 4 ... Carbon-based protective film.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C10N 60:00

Claims (9)

[Claims] 1. A diacylhydrazine having a fluorine-containing polyether represented by the general formula 1 in a side chain. [Chemical 1] (However, the average molecular weight distribution is 500 to 20,000) 2. A diacylhydrazine having a fluorine-containing polyether represented by the general formula 2 in the side chain. [Chemical 2] (However, the average molecular weight distribution is 500 to 20,000) 3. A diacylhydrazine having a fluorine-containing polyether represented by the general formula 3 in the side chain. [Chemical 3] (In the formula, R is a group selected from hydrogen, an alkyl group or an aromatic group, and the lubricant has an average molecular weight distribution of 500 to
It is 20,000. ) 4. A diacylhydrazine having a fluorine-containing polyether represented by the general formula 4 in the side chain. [Chemical 4] (In the formula, R is a group selected from hydrogen, an alkyl group or an aromatic group, and the lubricant has an average molecular weight distribution of 500 to
It is 20,000. ) 5. A diacylhydrazine having a fluorine-containing polyether represented by the general formula 5 in the side chain. [Chemical 5] (However, the average molecular weight distribution is 500 to 20,000) 6. A polydiacylhydrazine having a fluorine-containing polyether represented by the general formula 6 in the side chain. [Chemical 6] (However, the average molecular weight distribution is 500 to 200,000) 7. A lubricant comprising one or more compounds represented by the general formula 1, chemical formula 2, chemical formula 3, chemical formula 4, chemical formula 5, chemical formula 6 above. 8. A surface coated with a lubricant obtained by mixing one or more compounds represented by the general formula 1, chemical formula 2, chemical formula 3, chemical formula 4, chemical formula 5, chemical formula 6 above. Characteristic magnetic recording medium. 9. After applying a lubricant to the surface of the magnetic recording medium,
The magnetic recording medium according to claim 8, which has been subjected to a heat treatment or a light irradiation treatment.