JP2000119206A - Fluorine-containing secondary alcohol, lubricant and magnetic recording medium, and production of the same medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject new compound having excellent lubricating property and useful as a lubricant. SOLUTION: This compound is expressed by formula I R1 is an alkyl or alkenyl; R2 is a fluoroalkyl, fluoroether or fluoropolyether; (a)>=0}, e.g. a compound of formula II. The compound of formula I is obtained by reacting, e.g. an alkylglycidyl ether or an alkenylglycidyl ether with a fluorine-containing primary alcohol, preferably in a molar ratio of 1/1, after mixing while stirring together with a catalyst in a solvent (e.g. heptane) at preferably 80-150 deg.C. The compound of formula I is useful as a material constituting a lubricant and especially suitable for constituting a lubricant layer in a magnetic recording medium. A composition having excellent lubricating property is obtained by including 40 wt.% of the compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel fluorine-containing compound useful as a lubricant, a surfactant, a mold release agent or a rust inhibitor for use in precision machines or precision parts requiring high precision lubrication. The present invention relates to a secondary alcohol, a lubricant comprising such a fluorinated secondary alcohol, a magnetic recording medium using the lubricant, and a method for producing the magnetic recording medium.

[0002]

2. Description of the Related Art In recent years, in the field of magnetic recording, with the advancement of digitalization, miniaturization, and prolonged use time of recording / reproducing devices, development of high-density magnetic recording media suitable therefor has been required. It has been actively performed, and recently, a metal thin film type magnetic recording medium which is extremely advantageous for short wavelength recording has been put to practical use instead of a coating type magnetic recording medium. In general, a metal thin film type magnetic recording medium refers to a tape, a disk, or the like in which a magnetic layer made of a ferromagnetic metal thin film is provided as a recording layer on a nonmagnetic substrate.

However, the magnetic layer of a metal thin film type magnetic recording medium has extremely good surface properties, that is, the surface roughness of the magnetic layer is small, so that the contact area with the magnetic head increases. During the reproduction process, the magnetic head is easily worn due to a large frictional force while sliding at a high speed with the magnetic head. Abrasion of the magnetic layer greatly affects running durability, still durability, and the like of the magnetic recording medium, and reducing it is a major issue in research and development of metal thin-film magnetic recording media.

[0004] Therefore, attempts have been made to reduce wear by providing a lubricant layer on the surface of the magnetic layer to improve running durability and still durability. When a lubricant layer is provided, the lubricant layer on the surface of the magnetic layer exhibits lubricating properties with a thickness of only a few nm in order to minimize output loss due to spacing loss between the magnetic recording medium and the magnetic head and achieve high output. Is required. Therefore, the use of fluorine-based compounds exhibiting excellent lubrication properties has been widely studied, and the use of various compounds has been proposed. For example,

Embedded image Fluorinated long-chain carboxylic acid ester represented by C ₁₈ H ₃₅ OCOC ₉ F ₁₇
(See -46431) and (Chemical 15):

Embedded image It has been proposed to use a fluorine-containing carboxylic acid monoester having a carboxyl group (see JP-A-61-107529).

[0005]

However, there is a severe demand for improving the performance of a magnetic recording medium, and it is difficult to obtain sufficient lubricating characteristics with the above-mentioned conventional lubricant.
Further improvements in running durability and still durability are desired.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a lubricant capable of obtaining a magnetic recording medium having excellent running durability and still durability and high practical reliability without impairing the electromagnetic conversion characteristics, and a lubricating agent therefor. It is intended to provide a magnetic recording medium using an agent and a method for producing the same.

[0007]

The first gist of the present invention resides in a fluorine-containing compound having a specific structure. Such compounds have the general formula (a):

Embedded image (Wherein, R ¹ is an alkyl group or an alkenyl group;
R ² is a fluoroalkyl group or a fluoroether or fluoropolyether group, and a is an integer of 0 or more. ) Is a fluorine-containing secondary alcohol represented by the formula:

As is apparent from the above general formula, the fluorinated secondary alcohol of the present invention has a hydroxyl group and a group containing fluorine at one end of one molecule, that is, a fluoroalkyl group or a fluoroether or fluoropolyether group. And an aliphatic hydrocarbon group, that is, an alkyl group or an alkenyl group, at the other end, and further has at least two ether bonds. With this structure, when the fluorinated secondary alcohol of the present invention is contained in a lubricant, particularly a lubricant for a lubricant layer of a magnetic recording medium, the lubricant exhibits excellent lubricating properties. Therefore, the present invention also provides the fluorine-containing secondary alcohol of the present invention as a compound constituting a lubricant.

A second gist of the present invention resides in a lubricant comprising at least one kind of the above-mentioned fluorinated secondary alcohol of the present invention. The lubricant of the present invention is particularly suitable for forming a lubricant layer of a metal thin-film magnetic recording medium.

[0010] The lubricant of the present invention may further contain at least one kind of perfluoropolyether compound. The perfluoropolyether-based compound also functions as a lubricant, and by using this together with the fluorinated secondary alcohol of the present invention, more excellent lubrication performance can be imparted to the lubricant.

Further, the lubricant of the present invention may further contain at least one kind of organic phosphorus compound. That is, the lubricant of the present invention is a two-component composition containing the fluorinated secondary alcohol of the present invention and an organic phosphorus compound, or the fluorinated secondary alcohol of the present invention, the perfluoropolyether compound and It may be a three-component composition containing an organic phosphorus compound. The organophosphorus compound acts as a rust inhibitor and / or an extreme pressure agent. For example, when the composition is contained in a lubricant layer of a magnetic recording medium, a gap between the lubricant layer and the protective film is formed. Since it also plays a role of improving the adhesion strength of the magnetic recording medium, it is possible to further improve the lubrication performance and durability of the magnetic recording medium.

In the present invention, the general formulas (e), (f),
(G), (h), (i), (j), (k), (l) and (m):

Embedded image HP (O) (OC _n H _{2n + 1} ) ₂ ... (E)

Embedded image P (OC _n H _{2n + 1} ) ₃ ... (F)

_{Embedded image} P (SC _n H _{2n + 1} ) ₃ ... (G)

Embedded image O = P (OC _n H _{2n + 1} ) ₃ ... (H)

S = P (OC _n H _{2n + 1} ) ₃ ... (I)

Embedded image O = P (SC _n H _{2n + 1} ) ₃ ... (J)

S = P (SC _n H _{2n + 1} ) ₃ ... (K)

_{Embedded image} (C _n H _{2n + 1} O) ₂ P (O) OH (1)

_{Embedded image} (C _n H _{2n + 1} O) P (O) (OH) ₂ ... (M)
(In the above general formulas (e) to (m), n is 8 to 20)
Is an integer. It is preferable to use one or more organic phosphorus compounds selected from the group consisting of the organic phosphorus compounds represented by the formula (1).

A third aspect of the present invention is a magnetic recording system comprising a ferromagnetic metal film provided on a non-magnetic support, and a lubricant layer provided on the ferromagnetic metal film via a protective film. A medium, wherein the lubricant layer is a magnetic recording medium containing at least one of the above lubricants.

The action of the fluorinated secondary alcohol of the present invention represented by the general formula (a) in the magnetic recording medium of the present invention is considered to be as follows, but this does not limit the present invention at all. is not. The fluorine-containing group in the molecule of the general formula (a) is exposed to the surface of the metal thin film, the surface of the protective film, or the surface of the magnetic head to contribute to lowering the energy of the surface and form a non-adhesive surface. In addition, the ether bond has the effect of imparting flexibility to the rigid fluorine-containing end group to provide good lubricity, and enables the lubricant layer of the magnetic recording medium to have both non-adhesiveness and lubricity. .
This effect becomes more remarkable when the group containing fluorine is a fluoroether group or a fluoropolyether group having a fluoroalkylene oxide group. In addition, in this specification, a fluoroalkylene oxide group (namely, oxyfluoroalkylene group) is -O-
R _f - or _{-R f -O - (- R f} - is fluoroalkylene group, for example perfluoro alkylene group) refers to.

Further, since the carbon-carbon bond in the alkyl group or the alkenyl group in the molecule of the formula (a) is flexible, the lubricating property of the magnetic recording medium is further improved. The hydroxyl group in the molecule improves the solubility in general-purpose organic solvents and facilitates the production of a magnetic recording medium according to the production method of the present invention. Further, due to the presence of the hydroxyl group, the lubricant layer containing the fluorinated secondary alcohol of the present invention strongly adheres to the surface of the protective film, the surface of the magnetic head, and the surface of the metal member of the tape traveling system. And the magnetic recording medium of the present invention containing the fluorine-containing secondary alcohol of the present invention in the lubricant layer by the synergistic effect of each of these parts constituting the molecule, from a low-temperature low-humidity environment to a high-temperature high-humidity environment Lubricity does not decrease in a wide range of environments

A fourth aspect of the present invention is to provide a method for manufacturing the magnetic recording medium of the present invention. The method of manufacturing a magnetic recording medium according to the present invention is characterized in the step of forming the lubricant layer, and the other steps can use the steps used in conventional magnetic recording media. The step of forming the lubricant layer in the production method of the present invention protects the coating liquid prepared by dissolving the compound constituting the lubricant layer, that is, the lubricant, in a mixed organic solvent of a hydrocarbon solvent and an alcohol solvent. The method is characterized by including a step of coating on a film. By using a mixed solvent in which a hydrocarbon-based solvent and an alcohol-based solvent are combined, a uniform thin lubricant layer with extremely little coating unevenness can be formed. Therefore, according to the manufacturing method of the present invention, it is possible to obtain a highly practical magnetic recording medium having excellent lubrication performance.

In the method for producing a magnetic recording medium of the present invention, the mixing ratio of the hydrocarbon solvent and the alcohol solvent is preferably in the range of 1: 9 to 9: 1 by weight. Mixing both in this range makes it possible to minimize coating unevenness and is advantageous in terms of cost.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The fluorinated secondary alkyl alcohol of the present invention has the general formula (a):

Embedded image It is shown by.

In the general formula (a), R ¹ is an alkyl group or an alkenyl group, and the carbon number thereof is suitably 6 to 30, preferably 10 to 24, and when the number of carbon atoms is less than 6, or When it exceeds, the lubricity may be reduced.

R ² is a fluoroalkyl group or a fluoroether or fluoropolyether group. R ²
Is a fluoroalkyl group, the carbon number of which is 1 to 1
It is preferably 2, and more preferably 6 to 10. Further, the fluoroalkyl group is preferably a perfluoroalkyl group.

When R ² is a fluoroether group or a fluoropolyether group, its molecular weight is about 200-200.
It is preferably about 6000, and about 300 to about 4
000 is more preferable. When the molecular weight is less than 200 or more than 6,000, lubricity and storage reliability may decrease. Further, the fluoroether group or the fluoropolyether group is preferably a perfluoroether group or a perfluoropolyether group.

When R ² is a fluoroether group or a fluoropolyether group, R ² has the general formula (b):
(C) and (d):

Embedded image

Embedded image

Embedded image R ³ (OC _m F _2m ) _n O (CF ₂ ) _m-1 −. . . (D) It is preferable that it is shown by either.

K in the general formula (b) is an integer of 1 or more, preferably an integer of 1 to 8. P and q in the general formula (c) are integers of 1 or more.
It is preferably from 30 to 30, more preferably from 1 to 8. R ³ in the general formula (d) is a fluoroalkyl group, preferably a perfluoroalkyl group, and suitably has 1 to 30, preferably 1 to 8 carbon atoms.
m is usually an integer of 1 to 6, n is usually an integer of 1 to 30, and more preferably an integer of 1 to 8. K, p and q in the general formulas (c), (d) and (e),
If m and n are outside these ranges, the lubricity and storage reliability of the magnetic recording medium may decrease.

When the above-mentioned fluorinated secondary alcohol having a perfluoroether group or a fluoropolyether group is contained in the lubricant, for example, the lubricant is contained in the lubricant layer of the metal thin film type magnetic recording medium. In this case, the adhesion strength of the lubricant layer to the carbon film is further improved, and more excellent lubrication characteristics are imparted to the magnetic recording medium. By these synergistic effects, it is possible to obtain a magnetic recording medium with high practical reliability in which running durability and still durability are improved without impairing the electromagnetic conversion characteristics.

In the general formula (a), a is an integer of 0 or more, preferably 1 to 12, more preferably 1 to 8.

The fluorinated secondary alcohol of the present invention represented by the general formula (a) is prepared by (1) mixing and stirring an alkyl glycidyl ether or alkenyl glycidyl ether and a fluorinated primary alcohol together with a catalyst in a solvent. Or (2) a fluorine-containing glycidyl ether;
It can be produced by any method of mixing and stirring a primary alkyl alcohol or a primary alkenyl alcohol with a catalyst in a solvent. Hereinafter, each method will be described.

When the fluorinated secondary alcohol of the present invention is produced by the first production method, the reaction between the alkyl glycidyl ether or alkenyl glycidyl ether and the fluorinated alcohol is conveniently effected by heating and stirring in the presence of a solvent and a catalyst. proceed. At this time, the molar ratio of the alkyl glycidyl ether to the fluorinated alcohol was 1:
It is preferably 1. As the solvent, for example, heptane, octane, and toluene can be used, and as the catalyst, for example, anhydrous stannic chloride can be used. When the heating temperature is low, unreacted substances are likely to remain, while when it is high, a by-product tends to be generated. Therefore, the heating temperature is preferably 80 to 150 ° C, and is preferably 120 to 150 ° C.
More preferably, the temperature is in the range of 130 ° C.

The alkyl glycidyl ether or alkenyl glycidyl ether which can be used is represented by the following general formula (n):

Embedded image Indicated by In the formula, R ^{1 ′} is an alkyl group or an alkenyl group, which corresponds to R ¹ in the general formula (a). As R ^{1 ′} , for example, an octyl group, a nonyl group,
Decanyl group, undecanyl group, dodecanyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group,
Examples include a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a henycosyl group, a docosyl group, and an alkenyl group having 6 to 30 carbon atoms.

The fluorinated primary alcohol is a normal alcohol in which one of the hydrogens bonded to the terminal carbon atom not bonded to a hydroxyl group is a fluoroalkyl group (for example, a perfluoroalkyl group) or An alkyl alcohol substituted with a fluoroether or a fluoropolyether group (for example, a perfluoropolyether group). Examples of the alkyl alcohol include methanol, ethanol, propanol, and butanol.

In order to isolate the target compound from the obtained mixture, the solvent is first removed by distillation under reduced pressure, and the catalyst is deactivated by adding water. As a method for purifying the target compound, for example, a solvent extraction method such as liquid-liquid extraction using a separatory funnel,
Alternatively, there is a recrystallization method using an organic solvent. The target compound thus obtained can be identified by infrared spectroscopy (IR), gel permeation chromatography (GPC) and organic mass spectrometry (FD-MS).

When the fluorinated secondary alcohol of the present invention is produced by the second production method, the reaction between the fluorinated alkyl glycidyl ether and the primary alkyl alcohol is carried out in the same manner as in the first production method. Heating and stirring in the presence of a catalyst proceeds conveniently. In the second production method, the same temperature conditions, the molar ratio of both compounds, the solvent and the catalyst can be adopted as in the first production method. Therefore, description of them is omitted here.

The fluorine-containing glycidyl ether which can be used in the second production method is represented by the following general formula (o):

Embedded image Indicated by In the formula, R ^{2 ′} is a fluoroalkyl group (for example, a perfluoroalkyl group) or a fluoroether or a fluoropolyether group (for example, a perfluoropolyether group), which corresponds to R ² in the general formula (a). I do.

On the other hand, primary alkyl alcohols include, for example, octyl alcohol, nonyl alcohol, decanyl alcohol, undecanyl alcohol, dodecanyl alcohol, dodecyl alcohol, tridecyl alcohol,
It can be selected from tetradecyl alcohol, pentadecyl alcohol, hexadecyl alcohol, heptadecyl alcohol, octadecyl alcohol, nonadecyl alcohol, icosyl alcohol, henycosyl alcohol, docosyl alcohol and alkenyl alcohol.

The compound of interest can be isolated and identified by the same method as described in the first production method. Therefore, description of them is omitted here.

The thus obtained fluorine-containing secondary alcohol of the present invention is useful as a material constituting a lubricant. The lubricant of the present invention comprising at least one kind of the fluorinated secondary alcohol of the present invention is suitable for forming, for example, a lubricant layer of a magnetic recording medium. The lubricant of the present invention comprises the fluorinated secondary alcohol of the present invention in one form.
It may be a composition containing only species or a composition containing two or more species.

The lubricant of the present invention may be composed of only the fluorinated secondary alcohol of the present invention, but may further contain other lubricants, rust preventives, extreme pressure agents and the like as appropriate. It may be a composition. In that case, the proportion of the fluorinated secondary alcohol of the present invention is 4 to the total amount of the composition.
It is preferably at least 0% by weight, more preferably at least 60% by weight. When the proportion of the fluorinated secondary alcohol of the present invention is less than 40% by weight, for example, when a lubricant layer of a magnetic recording medium is formed with this composition,
In some cases, good lubrication properties cannot be imparted to the magnetic recording medium.

If a commercially available perfluoropolyether-based lubricant is used as the other lubricant, the lubricating performance is further improved. For example, when a lubricant containing the lubricant is used to form a lubricant layer of a magnetic recording medium. In addition, the durability of the magnetic recording medium is improved. Au is a commercially available perfluoropolyether.
Product name Fomblin Z type and Fomblin Y manufactured by simont
There are a Krytox type manufactured by Du-Pont and a Demnum type manufactured by Daikin Industries. These commercially available perfluoropolyether compounds include a nonpolar type and a type having a polar group, and in the present invention, a type having a polar group selected from a hydroxyl group, a carboxyl group, an ester, a piperonyl group and the like is preferable. Ausimont is a perfluoropolyether having a polar group.
Brand names Fomblin Z Dol (having a hydroxyl group as a polar group), Fomblin Z Diac (having a carboxyl group as a polar group) and Fomblin AM2001 (having a piperonyl group as a polar group) manufactured by Daikin Industries, Ltd. Demnum SA (having hydroxyl group as polar group) and Demnum SH (having carboxyl group as polar group)
There is. The molecular weight of a commercially available perfluoropolyether compound is generally from about 1,000 to about 20,000. In the present invention, those having a molecular weight of about 1,000 to about 4,000 are preferably used.

Since these perfluoropolyether compounds are hardly soluble in hydrocarbon solvents and alcohol solvents, for example, the present invention uses a lubricant containing these perfluoropolyether compounds. When the magnetic recording medium of the present invention is manufactured by the manufacturing method of the present invention,
The ratio of the perfluoropolyether compound to the total amount of the lubricant is preferably less than 60% by weight, and more preferably 10 to 40% by weight.

The lubricant of the present invention may further contain an organic phosphorus compound. In the present invention, the above general formulas (e) to (e)
It is preferable to use at least one organic phosphorus compound selected from the group consisting of the organic phosphorus compounds represented by (m). In the organic phosphorus compounds represented by the general formulas (e) to (m), the number of carbon atoms n is preferably from 8 to 20, and more preferably from 12 to 18. When the number of carbon atoms n is 21 or more, the solubility in general-purpose solvents such as hydrocarbon solvents and alcohol solvents described below tends to decrease. For example, when the lubricant layer of the magnetic recording medium is composed of a lubricant containing the same, the decrease in solubility in the general-purpose solvent may hinder the production of the magnetic recording medium by the production method of the present invention. When the carbon number n is 7 or less,
Lubrication performance of the lubricant may be reduced.

The proportion of the organic phosphorus compound in the total amount of the lubricant is preferably such that the mixing ratio of the fluorine-containing compound of the present invention is not less than 40% by weight, that is, less than 60% by weight. More preferably, it is 40% by weight. Also, when the lubricant is composed of the fluorine-containing compound of the present invention, three components of another lubricant and an organic phosphorus compound, the ratio of the fluorine-containing secondary alcohol of the present invention is based on the total amount of the lubricant. It is necessary to appropriately determine the contents of other lubricants and organic phosphorus compounds so as not to be less than 40% by weight. The same applies if the lubricant further comprises other components.

The magnetic recording medium of the present invention comprises a ferromagnetic metal film provided on a nonmagnetic support, and a lubricant layer provided on the ferromagnetic metal film via a protective film. Wherein the lubricant layer contains any one of the above lubricants. That is, the lubricant layer contains at least one kind of the fluorine-containing secondary alcohol of the present invention represented by the general formula (a), or at least one kind of perfluoropolyether compound and And / or a lubricant further comprising at least one organic phosphorus compound. May use any of the lubricants, the amount of the fluorine-containing secondary alcohols of the present invention contained in the lubricant layer, the surface 1 m ² per 0 lubricant layer.
Preferably 0.5 to 100 mg, and 0.1 to 50 mg.
Is more preferred. In order for such a small amount of the fluorinated secondary alcohol to be uniformly present in the lubricant layer, the lubricant layer of the magnetic recording medium of the present invention is desirably formed by the following method.

The lubricant layer is formed on the protective film after forming a ferromagnetic metal thin film and a protective film on the non-magnetic support in this order using conventional materials and means. The step of forming a lubricant layer includes a step of applying a coating solution prepared by dissolving the lubricant of the present invention in a mixed solvent of a hydrocarbon solvent and an alcohol solvent on a protective film, and a step of drying the mixed solvent. including. Finally, when the mixed solvent evaporates, the lubricant dissolved in the solvent remains on the protective film to form a lubricant layer. Therefore, even if the coating liquid is applied thickly, the solvent evaporates, forming a uniform and very thin lubricant layer on the protective film, that is, a lubricant layer in which a small amount of lubricant uniformly covers the protective film. Is done.

The hydrocarbon solvents usable in the present invention are, for example, toluene, hexane, heptane, octane, nonane, xylene, ketone, etc. The alcohol solvents usable in the present invention are, for example, methyl alcohol, ethyl alcohol It is a lower alcohol such as alcohol, propyl alcohol, isopropyl alcohol and butyl alcohol. If the proportion of the alcohol-based solvent is too large, coating unevenness is likely to occur. On the other hand, if the proportion of the hydrocarbon-based solvent is too large, it is uneconomical.
The mixture is used in a range of 9 to 9: 1, preferably in a range of 3: 7 to 7: 3. By using this mixed organic solvent, a lubricant layer having a uniform thickness without coating unevenness that uniformly covers the protective film is formed, and as a result, a highly reliable magnetic recording medium having excellent lubrication performance is obtained. .

The method of forming the lubricant layer using the above mixed solvent includes a wet coating method such as a bar coating method, a gravure coating method, a reverse coating method, a die coating method, a dipping method and a spin coating method, or an organic vapor deposition method. And either method may be adopted.

After applying the coating solution, the organic solvent is evaporated by a drying treatment, whereby a lubricant layer is formed on the protective film.
The drying treatment can be performed by heating or natural drying.

As described above, the magnetic recording medium of the present invention can be formed by using conventional materials and means for layers other than the lubricant layer.

For example, as the nonmagnetic support, a film made of polyethylene terephthalate, polyethylene naphthalate, aromatic polyamide or aromatic polyimide, an aluminum substrate or a glass substrate can be used. In order to achieve both practical reliability and good RF output value, the surface on the non-magnetic support, that is, the surface in contact with the ferromagnetic metal film, has a diameter of 200 to 3000 ° and a height of 50 to 400.
It is desirable that the projection forming process of Å has been performed.

The magnetic layer constituting the magnetic recording medium of the present invention is a ferromagnetic metal thin film formed by a method such as ion plating, sputtering or electron beam. Ni-O,
Co, Co-O, Co-Cr, or the like is appropriately selected. The thickness of the magnetic layer is generally 50 nm to 300 nm.

The protective film constituting the magnetic recording medium of the present invention may be a carbon thin film made of amorphous, graphite or diamond-like carbon obtained by a method such as sputtering or plasma CVD, or a mixture and / or mixture of such carbon. It can be formed using a stacked carbon thin film, silicon nitride film, or boron nitride film. In the present invention, it is particularly preferable to form the protective film with diamond-like carbon, that is, diamond-like carbon. Since diamond-like carbon has an appropriate hardness, it is the most preferable material because it can suppress damage to a magnetic recording medium and also prevent damage to a magnetic head. In any case where the thin film is formed using any of the materials, the thickness of the protective film is preferably 50 to 500 °.

As described above, the lubricant containing the fluorinated secondary alcohol of the present invention is contained in the lubricant layer of the magnetic recording medium. For example, it can be used as a material for a lubricant, a surfactant, a release agent or a rust preventive for precision machines or precision parts.

[0051]

The present invention will be described below in more detail with reference to examples. (Example 1) The first example of the present invention relates to the production of a fluorinated secondary alcohol. The compound produced in this example has the chemical formula (a1):

Embedded image Indicated by The compound represented by the chemical formula (a1) will be described with reference to the general formula (a). R ¹ is an octadecyl group having 18 carbon atoms, and R ² is a plurality of perfluoropentyl groups bonded as terminal groups. A group consisting of a fluoroalkylene oxide group, and a is 1.

Next, a method for producing the compound represented by the chemical formula (a1) will be described. The starting material has the following chemical formula (n
1):

Embedded image 32.6 g (0.10 mol) of an ether represented by the following formula (x1):

Embedded image 74.8 g (0.1) of a fluorinated primary alcohol represented by C ₅ F ₁₁ (OC ₃ F ₆ ) ₂ OC ₂ F ₄ CH ₂ OH ... (x1)
0 mol).

The above-mentioned raw materials, 500 ml of normal octane and 1 g of anhydrous stannic chloride were charged into a 1-liter flask equipped with a stirring blade, and reacted at 120 ° C. for 10 hours with stirring. After the reaction was completed, the mixture in the flask was cooled to room temperature, 2 ml of water was added to deactivate the catalyst, and anhydrous sodium sulfate was further added to dry the mixture. After filtration, normal octane was distilled off to obtain a reaction mixture. continue,
The reaction mixture was dissolved in methanol, cooled to 0 ° C. to precipitate crystals of the fluorinated secondary alcohol as the target compound, and unreacted ether and unreacted fluorinated primary alcohol were removed by filtration. After, 107g of transparent liquid
(Melting point: about 5 ° C.). This transparent liquid is analyzed by infrared spectroscopy,
GPC and FD-MS revealed that the substance was represented by the chemical formula (a1) and did not contain a starting material and a by-product. The infrared absorption spectrum of this compound is shown in FIG. 1, and infrared spectroscopy (IR) and GPC
And the matters determined by performing FD-MS are summarized below.

IR: disappearance of the absorption peak at 1,200 cm ^{-1 due} to the ether bond of glycidyl ether. GPC: glycidyl ether and alkyl alcohol having a fluoroalkylene oxide group were not detected. A fluorinated secondary alcohol was detected. FD-MS; main peak at m / e 1,074.

This example shows an example in which only one of the fluorinated secondary alcohols of the present invention was produced, but various compounds were produced by appropriately changing the starting materials. can do.

For example, in the above embodiment, the chemical formula (n
Instead of the ether represented by 1), for example, a compound represented by the chemical formula (n)
2), (n3) or (n4):

Embedded image

Embedded image

Embedded image By using an ether represented by the formula (a)
2), (a3) or (a4):

Embedded image

Embedded image

Embedded image Can be produced.

In Example 1, the chemical formula (x1)
In place of the fluorinated alcohol represented by
2), (x3), (x4) or (x5):

Embedded image

Embedded image

Embedded image C ₁₀ F ₂₁ (CH ₂ ) ₂ OH ... (x4)

By using a compound represented by C ₇ F ₁₅ (CH ₂ ) ₄ OH... (X5), the compound represented by the chemical formula (a)
5), (a6), (a7) or (a8):

Embedded image

Embedded image

Embedded image

Embedded image Can be produced.

Example 2 The second example also relates to the production of a fluorinated secondary alcohol. The compound produced in this example has the chemical formula (a9):

Embedded image Indicated by When the compound represented by the chemical formula (a9) is described with reference to the general formula (a), R ¹ is an isooctadecyl group having 18 carbon atoms, R ² is a perfluorodecyl group, and a is 2. .

Next, a method for producing the compound represented by the chemical formula (a9) will be described. The starting material has the following chemical formula (o
1):

Embedded image And 62.0 g (0.10 mol) of an ether represented by the following formula (y1):

Embedded image 27.0 g of isooctadecyl alcohol (0.
10 mol).

The above-mentioned raw materials were reacted in the same manner as in Example 1 using the same solvent and catalyst as used in Example 1, and then reacted with the solvent and unreacted material in the same manner as in Example 1. Was removed to obtain 89 g of a transparent liquid. The transparent liquid was analyzed by infrared spectroscopy, GPC and FD-MS to obtain a starting material and a chemical formula (a9) containing no by-products.
It turned out that it is a substance shown by. Infrared spectroscopy (IR) and GPC and FD
-The matters determined by performing MS are summarized below.

IR: disappearance of the absorption peak at 1,200 cm ^{−1 due} to the ether bond of glycidyl ether. GPC: glycidyl ether and primary alkyl alcohol were not detected. A fluorinated secondary alcohol was detected. FD-MS; main peak at m / e 890.

(Embodiment 3) Next, embodiments of the magnetic recording medium of the present invention will be described specifically, but the present invention is not limited to these embodiments. In this example, a 6.3 μm-thick polyester film was used as the non-magnetic support of the magnetic recording medium. This polyester film has, on its surface, several granular projections (average height 70 °, diameter 1 μm) with a gentle gradient provided by silica fine particles added in the film, per 100 μm ² ,
Further, relatively large projections caused by the fine particles of the polymerization catalyst residue were reduced as much as possible. Further, on the surface of the polyester, there were provided 1 × 10 ⁷ steep ridges per mm ² , each having silica colloid particles having a diameter of 150 ° as a nucleus and an ultraviolet curing epoxy resin as a binder.

On this polyester film, a Co—Ni ferromagnetic film (Ni content 2
0 mol%, film thickness 1000 °) was formed in the presence of a trace amount of oxygen. The oxygen content in the ferromagnetic film was 5% in atomic fraction.

Next, a plasma CV is formed on the ferromagnetic film.
A protective film of diamond-like carbon having a thickness of 50 ° was formed by Method D. Subsequently, a coating solution prepared by dissolving a fluorinated secondary alcohol represented by the chemical formula (a1) in a mixed organic solvent of isopropyl alcohol and toluene (weight ratio 1: 1) on the protective film was reverse-coated. After coating by a wet coating method using a roll coater, a drying treatment was performed to evaporate the solvent. Finally, a lubricant layer containing 10 mg of the fluorinated secondary alcohol per m ² of the surface was formed on the protective film.

This is cut into a predetermined width to form a magnetic tape.
5 ° C, 10% RH environment, and 40 ° C, 80% RH
Under the environment described above, using a commercially available 8 mm VTR, the output characteristics during repeated running were measured.
The number of runs before the decrease in dB or the start of output fluctuation was measured.

Example 4 A magnetic tape was produced in the same manner as in Example 3 except that the compound represented by the chemical formula (a2) was used instead of the compound represented by the chemical formula (a1). A similar test was performed.

Example 5 In Example 3, instead of the compound represented by the chemical formula (a1), a compound represented by the chemical formula (a1) and a known lubricant C ₁₇ H ₃₃ COOC ₂ H ₄ C were used.
Lubrication in which 10 mg / m ² of the lubricant composition was present on the protective film in the same manner as in Example 3 except that a lubricant composition in which ₈ F ₁₇ was mixed at a weight ratio of 1: 1 was used. A magnetic tape on which an agent layer was formed was prepared, and a similar test was performed.

Example 6 In Example 3, instead of the compound represented by the chemical formula (a1), a compound represented by the chemical formula (a1) and a commercially available lubricant, perfluoropolyether (Fomblin Z DOL, average molecular weight) were used. 2000: Ausim
ont Co.) and 10 mg / m ² of the lubricant composition on the protective film in the same manner as in Example 3, except that a lubricant composition in which the lubricant composition was mixed at a weight ratio of 3: 1 was used. A magnetic tape on which a lubricant layer was formed was prepared and subjected to the same test.

(Example 7) In Example 3, instead of the compound represented by the chemical formula (a1), a compound represented by the chemical formula (a1) and an organic phosphorus compound (C ₁₂ H ₂₅ S) ₃ P
And a lubricant layer containing 10 mg of the lubricant composition per 1 m ² on the protective film in the same manner as in Example 3 except that a lubricant composition in which the lubricant composition was mixed at a weight ratio of 2: 1 was used. The formed magnetic tape was manufactured and the same test was performed.

Table 1 shows the test results of Examples 3 to 7 described above. In Conventional Examples 1 and 2 in the table, a coating solution prepared by dissolving the compounds represented by the following formulas (Chemical formula 14) and (Chemical formula 15) in isopropyl alcohol was applied on a protective film by a wet coating method to form a lubricant layer. This is a magnetic tape formed with.

[0071]

[Table 1] Number of running magnetic tapes (times) 5 ° C, 10% R.C. H. 40 ° C, 80% R. H. Conventional example 1 80 90 Conventional example 2 100 110 Example 3 200 or more 200 or more Example 4 200 or more 200 or more Example 5 200 or more 200 or more Example 6 6 or more 200 or more Example 7 200 or more 200 or more It is clear that all the magnetic tape samples provided with the lubricant layer containing the fluorinated secondary alcohol of the present invention have excellent lubricity under low temperature and low humidity and under high temperature and high humidity. On the other hand, the lubricating properties of a conventional magnetic tape provided with a lubricant layer consisting of only a lubricant are clearly lowered at low temperature and low humidity or at high temperature and high humidity.

In Examples 3 to 7, a magnetic tape having a lubricant layer formed of a compound represented by the chemical formula (a1) or (a2), a compound represented by the chemical formula (a1) and a known lubricant or organic compound were used. The present invention relates to a magnetic tape in which a lubricant layer is formed from a mixture with a phosphorus compound, and has the chemical formulas (a3), (a4), (a5), (a6), and (a).
7), (a8) and (a9), and a similar effect was observed with a magnetic tape having a lubricant layer formed by mixing these compounds with a known lubricant or an organic phosphorus compound. Was.

(Embodiment 8) Next, another embodiment of the magnetic recording medium of the present invention will be specifically described. In this embodiment, the non-magnetic support of the magnetic recording medium has a diameter of 95 mm,
A non-magnetic Ni-P alloy plating having a thickness of 25 μm was applied to the surface of a 1.2-mm-thick Al alloy plate, and a projection having an average roughness of 50 ° and a maximum height of 300 ° was formed by texturing. On the nonmagnetic Ni-P alloy plating of the support, a 1300-mm-thick Cr underlayer and a 600-mm-thick Co-Ni ferromagnetic film were formed by a sputtering method.
Further, on the ferromagnetic film, a diamond-like carbon protective film having a thickness of 50 ° was formed by a plasma CVD method. Next, a coating solution obtained by dissolving a fluorinated secondary alcohol represented by the chemical formula (a1) in a mixed organic solvent of isopropyl alcohol and toluene (weight ratio 1: 1) was applied onto the protective film. 1m ² final grade alcohol
A lubricant layer was formed by applying a wet coating method (dipping method) so that 10 mg of the lubricant was present, thereby producing a magnetic disk.

The magnetic disk was subjected to CSS under an environment of 5 ° C. and 10% RH and under an environment of 40 ° C. and 80% RH.
(Contact start / stop) A test was performed, and the durability was determined by measuring the number of CSS times when the friction coefficient exceeded 1.0 or the number of CSS times when a head crash occurred.

Example 9 A magnetic disk was prepared in the same manner as in Example 8, except that the compound represented by the chemical formula (a2) was used instead of the compound represented by the chemical formula (a1). A similar test was performed.

Example 10 In Example 8, the same lubricant composition as used in Example 5, ie, the compound represented by chemical formula (a1), was used instead of the compound represented by chemical formula (a1). Lubricant C ₁₇ H ₃₃ COOC ₂ H ₄ C
Lubrication in which 10 mg of the lubricant composition was present on the protective film per 1 m ^{2 in the same} manner as in Example 8 except that a lubricant composition in which ₈ F ₁₇ was mixed at a ratio of 1: 1 by weight was used. A magnetic disk on which an agent layer was formed was manufactured, and a similar test was performed.

Example 11 In Example 7, the same lubricant composition as used in Example 6 was used in place of the compound of formula (a1), ie, the compound of formula (a1) and a commercially available lubricant Perfluoropolyether (trade name: Fomblin Z DOL, average molecular weight 2000: Ausi
(manufactured by mont) at a ratio of 3: 1 by weight in the same manner as in Example 8, except that 10 mg of the lubricant composition was present on the protective film per 1 m ^2. A magnetic disk on which a lubricant layer was formed was manufactured, and a similar test was performed.

Example 12 In Example 8, instead of the compound represented by the chemical formula (a1), the same lubricant composition as used in Example 7, that is, the compound represented by the chemical formula (a1) and an organic compound were used. A lubricant composition was formed on the protective film in the same manner as in Example 7, except that a lubricant composition in which a phosphorus compound (C ₁₂ H ₂₅ S) ₃ P was mixed at a weight ratio of 2: 1 was used. A magnetic disk on which a lubricant layer was formed in which a substance was present in an amount of 10 mg per 1 m ² was prepared, and a similar test was performed.

Table 2 shows the test results of Examples 8 to 12 described above. For the magnetic recording media of Conventional Examples 3 and 4 in the table, the coating solutions prepared by dissolving the compounds represented by the following formulas (Chemical formula 14) and (Chemical formula 15) in isopropyl alcohol were applied onto the protective film by a wet coating method. This is a magnetic disk on which a lubricant layer is formed.

[0080]

[Table 2] Number of times of magnetic disk CSS (times) 5 ° C, 10% R. H. 40 ° C, 80% R. H. Conventional example 3 5,000 8,000 Conventional example 4 18,000 * 15,000 Example 8 50,000 or more 50,000 or more Example 9 50,000 or more 50,000 or more Example 10 50,000 or more 50,000 or more Example 11 50,000 or more 50,000 or more Example 12 50,000 or more 50,000 or more Means head crash

From Table 2, it can be seen that all of the magnetic disks provided with a lubricant layer containing at least one kind of the fluorinated secondary alcohol of the present invention have low C under low temperature and low humidity and high temperature and high humidity.
It turns out that SS number is large and durability is excellent. On the other hand, a conventional magnetic disk provided with a lubricant layer consisting of only a lubricant has a small CSS frequency under low temperature and low humidity or high temperature and high humidity, and is clearly inferior in durability.

In Examples 8 to 12, chemical formula (a1) was used.
Alternatively, the present invention relates to a magnetic disk having a lubricant layer formed of a compound represented by (a2) and a magnetic disk having a lubricant layer formed of a mixture of a compound represented by chemical formula (a1) and a known lubricant or an organic phosphorus compound. Which are represented by the chemical formulas (a3), (a4), (a5), (a6),
Compounds represented by (a7), (a8) and (a9),
Similar effects were also observed with magnetic disks in which a lubricant layer was formed by mixing these compounds with a known lubricant or an organic phosphorus compound.

[0083]

The fluorine-containing secondary alcohol of the present invention comprises
One hydroxyl group, one fluorine-containing terminal group, ie, a fluoroalkyl terminal group or a fluoroether or fluoropolyether terminal group, and one aliphatic hydrocarbon terminal group, ie, an alkyl terminal group or alkenyl, in one molecule. It has a terminal group and further has at least two ether bonds. This compound has excellent lubricating properties and is useful as a lubricant for various machines, devices or parts.

For example, a lubricant comprising the fluorine-containing compound of the present invention is provided on a non-magnetic support, and a ferromagnetic metal thin film, a protective film and a lubricant layer are provided in this order on a lubricant layer of a magnetic recording medium. When contained in the compound of the present invention, due to the synergistic effect of each terminal group contained in the compound of the present invention, excellent lubricity and durability, and lubricity in a wide range of environments from low temperature and low humidity to high temperature and high humidity. A magnetic recording medium that does not decrease can be obtained. This magnetic recording medium is particularly suitable for use in a digital video tape recorder or a high definition video tape recorder.

Further, by further adding a perfluoropolyether-based lubricant and / or an organic phosphorus-based compound to the lubricant layer of the magnetic recording medium, the magnetic recording medium of the present invention has more excellent lubricity and durability. It will be.

Further, by forming the protective layer of the magnetic recording medium of the present invention from diamond-like carbon, the bonding force of molecules between the protective layer and the lubricant layer is improved, and the magnetic recording medium having more excellent durability is provided. Can be obtained.

For the lubricant layer of the magnetic recording medium of the present invention, a lubricant is dissolved in a mixed solvent of a hydrocarbon solvent and an alcohol solvent to prepare a coating solution, and this coating solution is applied on the protective film. Formed by Use of this mixed solvent suppresses coating unevenness and enables formation of a thin and uniform lubricant layer.

[Brief description of the drawings]

FIG. 1 is a view showing a result of infrared spectroscopic analysis of a fluorinated secondary alcohol produced in Example 1.

FIG. 2 is a diagram showing the results of infrared spectroscopy analysis of the synthetic fluorinated secondary alcohol produced in Example 2.

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[Procedure amendment]

[Submission date] September 21, 1999 (September 9, 1999
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

K in the general formula (b) is an integer of 1 or more, preferably an integer of 1 to 8. P and q in the general formula (c) are integers of 1 or more.
It is preferably from 30 to 30, more preferably from 1 to 8. R ³ in the general formula (d) is a fluoroalkyl group, preferably a perfluoroalkyl group, and suitably has 1 to 30, preferably 1 to 8 carbon atoms.
m is usually an integer of 1 to 6, n is usually an integer of 1 to 30, and more preferably an integer of 1 to 8. K, p and q in the general formulas (b), (c) and (d),
If m and n are outside these ranges, the lubricity and storage reliability of the magnetic recording medium may decrease.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a view showing a result of infrared spectroscopic analysis of a fluorinated secondary alcohol produced in Example 1.

FIG. 2 is a view showing a result of an infrared spectroscopic analysis of the fluorinated secondary alcohol produced in Example 2.

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

[Procedure amendment 4]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) // (C10M 141/10 131: 04 137: 04) C10N 30:06 30:08

Claims (11)

[Claims] 1. A compound of the general formula (a): (Wherein, R ¹ is an alkyl group or an alkenyl group;
R ² is a fluoroalkyl group or a fluoroether or fluoropolyether group, and a is an integer of 0 or more. ) A fluorine-containing secondary alcohol represented by the formula: 2. The fluoroether or fluoropolyether group of the fluorinated secondary alcohol has the general formula (b), (c) or (d): (In the formula, k is an integer of 1 or more.) (Wherein, p, q is an integer of 1 or more.) Embedded image _{^{R 3 (OC m F 2m)}} n O (CF 2) m-1 - ... (d) ( wherein, R ³ Is a fluoroalkyl group, m is an integer of 1 to 6, and n is an integer of 1 to 30.). 3. The fluorinated secondary alcohol according to claim 1 or 2 for a lubricant. 4. A lubricant comprising at least one fluorine-containing secondary alcohol according to claim 1 or 2. 5. The lubricant according to claim 4, further comprising at least one perfluoropolyether compound. 6. The lubricant according to claim 4, further comprising at least one organic phosphorus compound. 7. An organic phosphorus compound represented by the general formula (e):
(F), (g), (h), (i), (j), (k),
(L) and (m): ## STR5 ## HP (O) (OC _n H _{2n + 1} ) ₂ ... (E) P (OC _n H _{2n + 1} ) ₃ . P (SC _n H _{2n + 1} ) ₃ ... (g) O = P (OC _n H _{2n + 1} ) ₃ ... (h) S = P (OC _n H _{2n + 1} ) ₃ ... (i) O = P (SC _n H _{2n + 1} ) ₃ ... (j) S = P (SC _n H _{2n + 1) 3} ... (k) embedded image _{(C n H 2n + 1 O} ) 2 P (O) OH ... (l) [of 13] _{(C n H 2n + 1 O} ) P (O ) (OH) ₂ ... (m) (in the above general formulas (e) to (m), n is 8 to 20)
Is an integer. 7. The lubricant according to claim 6, wherein the lubricant is at least one organic phosphorus compound selected from the group consisting of the organic phosphorus compounds represented by the formula (1). 8. A magnetic recording medium comprising: a ferromagnetic metal film provided on a non-magnetic support; and a lubricant layer provided on the ferromagnetic metal film via a protective film. The layers are
A magnetic recording medium comprising the lubricant according to any one of claims 4 to 7. 9. The magnetic recording medium according to claim 8, wherein the protective film is diamond-like carbon. 10. The method of manufacturing a magnetic recording medium according to claim 8, wherein the step of forming the lubricant layer comprises adding a lubricant to a mixed organic solvent of a hydrocarbon solvent and an alcohol solvent. A method for producing a magnetic recording medium, comprising a step of applying a coating solution prepared by dissolution on a protective film. 11. The method according to claim 10, wherein the mixing ratio of the hydrocarbon solvent and the alcohol solvent is in the range of 1: 9 to 9: 1 by weight.