JPH07118204A - Fluorine-containing compound and magnetic recording medium having the same - Google Patents

Abstract

PURPOSE:To provide a novel fluorine-containing compound expressing excellent lubricity not deteriorated even after stored under a high temperature environment. CONSTITUTION:A novel fluorine-containing compound is one of formula I (Rf is fluoroalkyl, fluoroalkenyl, fluorophenyl, fluoroalkylether; R1 is aliphatic alkyl, aliphatic alkenyl; R2 is saturated or unsaturated hydrocarbon chain; R3 is 2 or 3C aliphatic alkylene oxide; k, n are 0, 1; m is an integer of >=1), e.g. a compound of formula II. This example compound is synthesized from octadecylthiomalic acid anhydride of formula III and an ethyleneoxide group- added fluoroalkyl ether alcohol of formula IV as starting raw materials. A ferromagnetic film and subsequently a lubricant layer containing one or more kinds of the compound of formula I directly or through a protecting layer are disposed on a non-magnetic support to provide a magnetic recording medium.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel fluorine-containing compound useful as a precision machine requiring high precision lubricity, a lubricant for precision parts, a surfactant, a release agent, an anticorrosive agent, etc. A magnetic recording medium having the same.

[0002]

2. Description of the Related Art With the miniaturization and high precision of mechanical devices and parts, the lubrication mode of their sliding parts has been shifting from fluid lubrication to boundary lubrication. In particular, in electronic devices such as VTRs and magnetic disks, and electronic components, the use of a ferromagnetic metal thin film for the purpose of improving the recording density requires high-precision lubrication for sliding between the magnetic recording medium and the magnetic head. It's coming. For example, in a hard disk, the lubricant layer on the surface of the magnetic layer has a thickness of only several tens of liters in order to reduce the spacing loss between the magnetic recording medium and the magnetic head as much as possible and to achieve high output while ensuring durability and reliability. It is formed to be. Therefore, development of an organic compound having excellent lubricity has become an important issue as a material for forming the lubricant layer.

As a lubricant for a hard disk, the product name FOMBL manufactured by Montedison Co.
INZ DOL, a carboxylic acid with a fluoroalkyl ether group represented by (Chemical Formula 3) (JP-A-4-270243), and the like.

[0004]

[Chemical 2]

[0005]

[Chemical 3]

[0006]

However, the lubricant of FOMBLIN Z DOL represented by the above (Chemical formula 2) has an increased friction coefficient in a high temperature and high humidity environment and has a CSS (contact start stop) durability characteristic. Deteriorates,
The fluoroalkyl ether group-containing carboxylic acid lubricant represented by Chemical Formula 3 has a problem that the amount of the lubricant is reduced and the lubricity is deteriorated during storage in a high temperature environment.

The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a substance which does not deteriorate in lubricity even after storage in a high temperature environment.

[0008]

The substance of the present invention for achieving the above object is a fluorine-containing compound represented by the general formula (Formula 4).

[0009]

[Chemical 4]

However, Rf represents a fluoroalkyl group, a fluoroalkenyl group, a fluorophenyl group or a fluoroalkyl ether group, R ₁ represents an aliphatic alkyl group or an aliphatic alkenyl group, and R ₂ represents a saturated or unsaturated carbonized group. Represents a hydrogen chain, R ₃ represents an aliphatic alkylene oxide group having 2 or 3 carbon atoms, k and n represent 0 or 1, and m represents an integer of 1 or more.

The aliphatic alkyl group or the aliphatic alkenyl group (R ₁ ) has 6 to 30, preferably 10 carbon atoms.
-24 is suitable, and if the carbon number is less than 6 or more than 30, the lubricity decreases. Rf has 3 to 3 carbon atoms
0, preferably a 6-18 fluoroalkyl group, a carbon number which may have an ether or a phenylated ether as a linking group is 3-30, preferably a 6-18 fluoroalkenyl group, a carbon number of 6-18, Fluorophenyl group having 6 to 12 carbon atoms, 5 to 50 carbon atoms, preferably 5 to 3 carbon atoms
A 0 fluoroalkyl ether group is suitable, and if the carbon number is out of these ranges, the lubricity decreases.

In the magnetic recording medium of the present invention, a ferromagnetic film is provided on a non-magnetic support, and the fluorine-containing compound represented by the general formula (Chem. 4) is directly formed on the ferromagnetic film or through a protective film. Is provided with a lubricant layer containing one or more of

In this lubricant layer, the fluorine-containing compound represented by the general formula (Formula 4) is present alone or in the form of a thin layer by adding other lubricants, rust preventives and the like. Its abundance is surface 1
A range of 0.05 to 100 mg, preferably 0.1 to 50 mg per m ² is suitable. Further, a fluorine-containing compound is preferable as the other lubricant or rust preventive. The amount added is 0
A range of -80%, preferably 0-70% is suitable.
If the content of the fluorine-containing compound represented by the general formula (Formula 4) is less than 20%, the effect of the present invention is difficult to obtain. As the protective film, a carbon thin film obtained by a method such as sputtering or plasma CVD in an amorphous form, a graphite form, a diamond form, or a mixed state or a laminated state thereof can be applied, and the thickness thereof is preferably 50 to 500 Å.

[0014]

The fluorine-containing compound of the present invention is one fluorine-containing hydrocarbon group having an aliphatic alkylene oxide group in the same molecule, that is, a fluoroalkyl group having an aliphatic alkylene oxide group and a fluoroalkenyl group having an aliphatic alkylene oxide group. , A structure having a fluorophenyl group with an aliphatic alkylene oxide group or a fluoroalkyl ether group with an aliphatic alkylene oxide group and one aliphatic hydrocarbon group, that is, an aliphatic alkyl group or an aliphatic alkenyl group and a carboxyl group. Here, the aliphatic alkylene oxide group contributes to the increase in the molecular weight of the lubricant. Thereby, a volatilization suppressing effect can be given to the lubricant.

By the way, the carboxyl group strongly adheres to the surface of the metal thin film or the surface of the protective film and the surface of the magnetic head. The fluorine-containing hydrocarbon group is exposed on the surface and contributes to lowering the energy of the surface, forming a non-adhesive surface. Further, the aliphatic hydrocarbon group is a flexible carbon-carbon bond chain, and exhibits good lubricity because it is oriented by a proper intermolecular interaction with the hydrocarbon chains of other adjacent molecules.

Therefore, due to the synergistic effect of each of these groups, excellent lubricity is exhibited without deterioration of lubricity even after storage in a high temperature environment.

[0017]

【Example】

(Embodiment 1) Hereinafter, the first embodiment of the present invention will be specifically described.

The chemical formula of the substance of this embodiment is represented by (Chemical Formula 5).

[0019]

[Chemical 5]

Explaining the compound of (Chemical Formula 5) in comparison with the general formula of (Chemical Formula 4), R ₁ is an octadecyl group having 18 carbon atoms, and R _f is a fluoroalkyl having 8 carbon atoms bonded to fluorine. R ₂ is an aliphatic alkylene group having 2 carbon atoms, R ₃ is an ethylene oxide group, k is 0, and m is 3
And n is 0.

Next, a method for producing the substance represented by Chemical formula 5 will be described. Starting materials were octadecyl succinic anhydride 35.3 g (0.10 mol) represented by (Chemical Formula 6) and (Chemical Formula 7).
Is 59.6 g (0.10 mol) of an ethylene oxide-group-containing fluoroalkyl alcohol.

[0022]

[Chemical 6]

[0023]

[Chemical 7]

The above raw materials and 500 ml of normal heptane were sampled in a 1 liter flask equipped with a stirring blade and reacted for 24 hours. After completion of the reaction, normal heptane was distilled off, the reaction mixture was dissolved in benzene and cooled to -10 ° C to remove unreacted octadecyl succinic anhydride. Further, the reaction mixture was treated with a methanol solution in the same manner to remove unreacted fluoroalkyl alcohol having an ethylene oxide group to obtain 94.9 g of a white solid. This white solid was analyzed by infrared spectroscopy (IR), gel permeation chromatography (GPC) and organic mass spectrometry (FD-).
By MS), it was found to be a substance represented by the formula (Formula 5) containing no starting material and by-products.

IR; extinction of absorption peak of acid anhydride at 1,775 cm ⁻¹ and absorption peak of alcohol at 3,330 cm ⁻¹ , carboxylic acid at 1,705 cm ⁻¹ , ester at 1,735
Appearance of absorption peak at cm ^-1 .

GPC: Fluoroalkyl alcohol with ethylene oxide group, octadecyl succinic anhydride was not detected.

FD-MS; main peak at m / e 949. Although octadecyl succinic anhydride is used as the aliphatic alkyl succinic anhydride in this example, an aliphatic alkenyl succinic anhydride may be used instead. This also applies to the other embodiments.

(Embodiment 2) The second embodiment of the present invention will be specifically described below.

The chemical formula of the substance of this embodiment is represented by the chemical formula (8).

[0030]

[Chemical 8]

Explaining the substance of (Chemical Formula 8) in comparison with the general formula of (Chemical Formula 4), R ₁ is an octadecyl group having 18 carbon atoms, and R _f is a fluorocarbon having an average carbon number of 11 bonded to fluorine. An alkyl ether group, R ₂ is an aliphatic alkylene group having 1 carbon atom, R ₃ is an ethylene oxide group, k
Is 1, m is 3, and n is 0. Next, a method for producing the substance represented by Chemical formula 8 will be described.

The starting materials were octadecyl thiomalic anhydride 38.5 g (0.10 mol) represented by (Chemical Formula 9) and (Chemical Formula 1).
0) is 79.6 g (0.10 mol) of an ethylene oxide group-containing fluoroalkyl ether alcohol.

[0033]

[Chemical 9]

[0034]

[Chemical 10]

The above raw materials and 500 ml of normal heptane were collected in a 1 liter flask equipped with a stirring blade and reacted for 24 hours. After completion of the reaction, normal heptane was distilled off, the reaction mixture was dissolved in benzene and cooled to -10 ° C to remove unreacted octadecyl thiomalic anhydride.
Further, the reaction mixture was treated with a methanol solution in the same manner to remove the unreacted fluoroalkyl ether alcohol with an ethylene oxide group to give a waxy semi-solid 1.
18.1 g was obtained. This waxy semi-solid is IR, GP
By C and FD-MS, it was found to be a substance represented by the formula (Formula 8) containing no starting material and by-products.

IR; extinction of absorption peak of acid anhydride at 1,775 cm ^-1 and absorption peak of alcohol at 3,330 cm ^-1 , carboxylic acid at 1,705 cm ^-1 , ester at 1,735
Appearance of absorption peak at cm ^-1 .

GPC: Fluoroalkyl ether alcohol with ethylene oxide group, octadecyl thiomalic anhydride, not detected.

FD-MS; main peak at m / e 1,181. (Embodiment 3) Next, an embodiment of the magnetic recording medium of the present invention will be specifically described.

The non-magnetic support of the magnetic recording medium of the present embodiment was prepared by applying a non-magnetic Ni--P alloy plating of 25 μm thickness on the surface of an Al alloy plate having a diameter of 95 mm and a thickness of 1.2 mm, and then averaged by texturing. A protrusion having a roughness of 50Å and a maximum height of 300Å was used. 1300Å Cr with a thickness of 1300Å by sputtering on non-magnetic Ni-P alloy plating
Form a 600 Å thick Co-Ni ferromagnetic film on the base,
Further, a disk A is formed by forming a graphite protective film having a thickness of 200Å on the ferromagnetic film by a sputtering method. A disk B is formed by forming a diamond-like carbon protective film having a thickness of 50Å by a plasma CVD method instead of the graphite protective film. The disk on which the protective film is not formed is referred to as disk C.
Next, the fluorine-containing compound of Chemical formula 5 was applied onto these disks in an amount of 10 mg per m ² , and a lubricant layer was provided to prepare magnetic disks. This magnetic disk was incorporated into a hard disk drive, and the volatilization characteristics were judged from the residual ratio of the lubricant on the disk after 500 hours of continuous operation at 3600 rpm in an environment of 60 ° C. Using the disk after the volatilization characteristic test, 40 ° C-80%, which is severe for running
The CSS test was conducted at RH, and the number of CSSs when the friction coefficient exceeded 1.0 or the CS when the head crash occurred
The durability was judged by the number of times of S.

(Example 4) In the disk C of Example 3, a magnetic disk using (Chemical formula 8) instead of (Chemical formula 5) was prepared and the same test was conducted.

(Embodiment 5) In the disk B of Embodiment 3, instead of (Chemical formula 5), (Chemical formula 5) and a known lubricant C ₈ F _{17 were used.}
A similar test was conducted by preparing a disk B using a mixture of C ₂ H ₄ NHC ₁₈ H ₃₅ in a weight ratio of 2: 1.

[0042] (Example 6) the disc A of Example 7, (Formula 5) to a place (of 8) with known lubricants C ₁₇ H ₃₃
A similar test was conducted by making a magnetic disk using a mixture of COOC ₂ H ₄ C ₆ F ₁₃ in a weight ratio of 1: 1.

The test results of the above examples are shown in (Table 1). The lubricant of Conventional Example 1 in the table is shown in (Chemical Formula 2),
The lubricants of Conventional Example 2 and Conventional Example 3 are shown in (Chemical Formula 3).

[0044]

[Table 1]

From Table 1, it can be seen that all the magnetic disks provided with the lubricant layer containing at least one fluorine-containing compound of the present invention have excellent volatility and CSS durability after a high temperature environment test. it is obvious. On the other hand, it is clear that the conventional magnetic disk provided with a lubricant layer consisting of only a lubricant has poor volatility and CSS durability after a high temperature environment test.

In the embodiment, (Chemical formula 5) and (Chemical formula 8)
I explained about the substance of (Chemical formula 11), (Chemical formula 12),
(Chemical formula 13), (Chemical formula 14), (Chemical formula 15) and (Chemical formula 16)
Similar effects can be obtained with the above substances.

[0047]

[Chemical 11]

[0048]

[Chemical 12]

[0049]

[Chemical 13]

[0050]

[Chemical 14]

[0051]

[Chemical 15]

[0052]

[Chemical 16]

[0053]

As is apparent from the above description, the fluorine-containing compound of the present invention has one aliphatic alkylene oxide group-containing fluorine-containing hydrocarbon group in the same molecule, that is, an aliphatic alkylene oxide group-containing fluoroalkyl group. Group, a fluoroalkenyl group with an aliphatic alkylene oxide group, a fluorophenyl group with an aliphatic alkylene oxide group, or a fluoroalkyl ether group with an aliphatic alkylene oxide group and one aliphatic hydrocarbon group, that is, an aliphatic alkyl group or an aliphatic group Since it has a structure having an alkenyl group and a carboxyl group, it exhibits an excellent effect that the lubricity does not decrease even after storage in a high temperature environment.

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Claims (2)

[Claims] 1. A fluorine-containing compound represented by the general formula (Formula 1). [Chemical 1] However, Rf represents a fluoroalkyl group, a fluoroalkenyl group, a fluorophenyl group or a fluoroalkyl ether group, R ₁ represents an aliphatic alkyl group or an aliphatic alkenyl group, and R ₂ represents a saturated or unsaturated hydrocarbon chain. R ₃ represents an aliphatic alkylene oxide group having 2 or 3 carbon atoms, k and n represent 0 or 1, and m represents an integer of 1 or more. 2. A ferromagnetic film is provided on a non-magnetic support, and one or more fluorine-containing compounds represented by the general formula (Chemical Formula 1) are contained on the ferromagnetic film directly or through a protective film. A magnetic recording medium provided with a lubricant layer.