JP2866622B2 - New fluorine-containing compound, lubricant containing the same, and magnetic recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel fluorine-containing compound. More specifically, the present invention relates to a novel fluorine-containing compound useful as a lubricant component, a wax component and the like, and its application.

[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 also shifted from liquid lubrication to boundary lubrication. In particular, in electronic devices and electronic components such as VTRs and magnetic disks, the use of a ferromagnetic metal thin film for the purpose of improving the recording density enables high-precision lubrication for sliding between the magnetic tape or magnetic disk and the magnetic head. Is needed. For example, a lubricant layer on the surface of a magnetic layer is required to minimize the spacing loss between the magnetic recording medium and the magnetic head and to increase the output while securing the durability and practical reliability of the evaporated tape or hard disk. It is formed to have a thickness of only several tens of square meters. In addition, since the magnetic layer surface of the ferromagnetic metal thin film type magnetic recording medium has extremely good smoothness, the contact area with a head, a guide roller, or the like becomes large, and adhesive development (adhesion, etc.) occurs.
There are many drawbacks in durability, running properties, etc., such as occurrence of friction and an increase in the coefficient of friction. Therefore, as a material for forming this lubricant layer,
In particular, the development of organic compounds having excellent lubrication performance has become an important issue.

As a lubricant for a metal thin-film type magnetic recording medium, those having a fluorocarbon chain in the molecule are excellent in compatibility with a metal thin film, and hence a large number of fluorocarbon-based lubricants have been proposed. . For example, perfluoroalkyl polyethers are well-known lubricants for magnetic recording media. It has also been proposed to use a polar compound-introduced fluorine compound as a lubricant.
For example, JP-A-62-103838 describes formation of a lubricant layer containing a perfluoroalkylcarboxylic acid ester and a perfluoropolyether.
Further, in JP-open flat 4-178357 discloses a (R) (Rf) fluorine-containing compound represented by NH and lubricant compositions containing them. Further, in JP-open flat _{4-271013 R 1 (CH 2) n} COO
^- the H ₃ N ⁺ perfluoro carboxylic acid amine salt compound represented by R can be used as a lubricant for magnetic recording medium are described. Further, in JP-open flat 7-220267 discloses that used as a lubricant for magnetic recording medium a fluoroalkyl carboxylic acid ester of the particular three kinds containing hydrocarbon chain with an unsaturated bond.

[0004]

As a lubricant for a magnetic recording medium, in particular, a metal thin film type magnetic recording medium, there is a problem of spacing with a head. Therefore, an extremely thin lubricating layer can be formed. It is necessary to be able to withstand long-term use over a wide temperature and humidity range and maintain the lubricating effect. He is dissatisfied with practical characteristics. In particular, sustaining the lubricating effect over a wide temperature and humidity range as described above has not been sufficiently achieved. Therefore, a decrease in the lubrication effect due to environmental changes cannot be sufficiently suppressed. Further, in order to achieve the above object, the lubricant is generally formed by diluting. However, conventionally, a perfluoropolyether-based lubricant generally used in the art is soluble only in a fluorine-based solvent. Fluorine-based solvents are expensive, and there is a concern about destruction of the ozone layer and global warming. Therefore, they cannot be said to be suitable solvents in terms of cost and environment, and improvement is desired in this respect.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a novel fluorine-containing compound is effective as a lubricant component. Reached.

That is, the present invention provides a fluorine-containing compound represented by the following general formula. .

[0007]

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[Wherein, Rf: a fluoroalkyl group R: an alkenyl group having at least one double bond and optionally having a polar group]

[0009]

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X, Y: —O— or absent Z ₁ : polar group l: an integer of 0 or more] Further, the present invention relates to a lubricant comprising a fluorine-containing compound represented by the above general formula, and a support. And a magnetic recording medium comprising: a magnetic layer formed on the support; and a layer containing a lubricant composed of the fluorine-containing compound represented by the above general formula. Hereinafter, the present invention will be described in detail.

[Fluorine-Containing Compound] The novel fluorine-containing compound of the present invention is represented by the above general formula, in which a fluoroalkyl group represented by Rf and an alkenyl group represented by R 2 form a polar group Z It is characterized by having a structure linked by an alkylene group R ′ having ₁ . As Rf in the formula, a linear or branched fluoroalkyl group having a total of 5 to 20 carbon atoms is preferable. Further, the fluoroalkyl group is not necessarily required to be perfluoro, and a portion adjacent to the connecting portion X may include an alkylene group such as methylene. Further, the compound may have an ether bond in the molecule. If the total carbon number of Rf is less than 5, lubricity is not sufficient when used as a lubricant for a magnetic recording medium, and when the total carbon number is
If it exceeds 50, the effect of the polar group is reduced, and the solubility in a solvent is deteriorated. In addition, R in the formula is preferably a linear or branched alkenyl group having 6 to 35, preferably 8 to 26 carbon atoms. Further, the alkenyl group R 1 may have two or more double bonds. When the carbon number of R is less than 6 or more than 35, lubricity is not sufficient when used as a lubricant for a magnetic recording medium. In addition, it is preferable that the number C ₁ of carbons of Rf and the number C ₂ of carbons of R satisfy the relationship of C ₁ <C ₂ from the viewpoint of compatibility with an organic solvent and the like. Further, m and n in the R ′ portion in the formula are each an integer of 0 to 10, preferably 0 to 5. In the formula, l is an integer of 0 or more, preferably 0 to 30, more preferably 0 to 10. X and Y in the formula are -O- groups or are not present. In the latter case, it means a carbon-carbon single bond.

The novel fluorine-containing compound of the present invention comprises a polar group Z ₁
But the alkenyl group R is a polar group
Z ₂ may be contained. When the polar group Z ₂ is contained, it may be the same as or different from the polar group Z _1, and the position may be the chain or the terminal of the alkenyl group R 1. Examples of the polar groups Z ₁ and Z ₂ are shown below.

[0013]

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Next, a typical method for producing the fluorine-containing compound of the present invention will be described. <Production Method 1> Starting from a fluorine-containing compound (a) having a terminal halogen (Cl, Br, I) having a polar group and an unsaturated long-chain alcohol (a) having the following polar groups, the presence of an alkali under heating of both compounds React down.

[0015]

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Specifically, unsaturated long-chain alcohols (a)
With tetrahydrofuran (THF), dimethylsulfoxide (DMSO), dimethylformamide (DMF),
It is added to a polar solvent such as dioxane, and a fluorine-containing compound (a) having a polar group is added dropwise in the presence of a base such as NaH or KOH to react (a) with (a), thereby obtaining the present invention. This is a method for obtaining a fluorine-containing compound represented by the general formula.
Here, the charge ratio of the fluorine-containing compound (a) having a polar group to the unsaturated long-chain alcohol (a) is (a) :( a) =
It is about 1: 3 to 3: 1 (molar ratio). The reaction is 50
Perform under heating at ~ 100 ° C. The amount of NaH used is about 0.5 to 2 equivalents to the starting compound (a). As long-chain unsaturated alcohols, 10-undecenyl alcohol, cis-9-tetradecenyl alcohol, cis-9-hexadecenyl alcohol, cis-9-octadecenyl alcohol, cis-9-, cis-12-octadecadienyl alcohol and the like. In addition, instead of the unsaturated long-chain alcohol,
Hydroxy unsaturated carboxylic acid esters such as 11-hydroxyundecenoic acid ester can also be used.

The above-mentioned production method is an example, and the method is not limited to the above-mentioned method as long as a compound corresponding to the general formula of the present invention can be obtained.

The novel fluorine-containing compound of the present invention can be used as a lubricant for a magnetic recording medium, and has a fluoroalkyl group Rf and an alkenyl group R in the molecule and at least one polar group. It is expected to be used as waxes, surfactants, rust inhibitors and the like. Further, it is considered that the physical properties can be changed by further modifying the polar group at the terminal, and the present invention can be applied to uses other than the above. Further, the fluorine-containing compound of the present invention includes toluene, methanol, ethanol, tetrahydrofuran (THF),
Since it is soluble in various general-purpose organic solvents such as chloroform, methyl ethyl ketone (MEK), dimethylformamide (DMF), and cyclohexanone, it is advantageous in terms of cost and usage.

[Lubricant] The fluorine-containing compound of the present invention represented by the above formula is particularly useful as a lubricant. The use of the lubricant is not limited, but it is particularly preferable to use it as a lubricant for a magnetic recording medium. In the case of a lubricant for a magnetic recording medium, the lubricant layer is applied directly on a magnetic layer in the magnetic recording medium in a thin film form or is applied in a thin film form via a protective layer provided on the magnetic layer. Act as The method of applying the lubricant is not particularly limited, and for example, a wet coating method using a sprayer equipped with an ultrasonic oscillator can be used. After the formation of the lubricating layer, cleaning may be performed with a solvent. The lubricant may be in the form of a liquid or a wask. When used, the lubricant is diluted with an appropriate solvent and then applied by the above method.

In the case of a lubricant for a magnetic recording medium, the content (adhesion amount) of the above-mentioned fluorine-containing compound can be appropriately adjusted according to the form (tape, disk) of the magnetic recording medium. The content (adhesion amount) in a suitable range is preferably from 0.1 to 100 mg, more preferably from 1 to 50 mg, per m ² of the surface of the magnetic recording medium. When the content (adhesion amount) is less than 0.1 mg / m ^2, sufficient lubricity, no durability is obtained, it may damage the head and the tape, when it exceeds 100 mg / m ^2, beam tape Since there is a case in which sticking and clogging of the head may occur, it is preferable to be within the above range.

In the present invention, the above-mentioned fluorine-containing compounds may be used alone or in combination of two or more. Further, the fluorine-containing compounds may be used in combination with a lubricant usually used for a magnetic recording medium. May be. Furthermore, if necessary, other additives such as phenols, quinones and naphthols, and a heterocyclic compound containing a nitrogen atom, an oxygen atom or a sulfur atom may be used in combination. In these cases, the lubricant and the additive can be added in an amount of 1 to 500 parts by weight based on 100 parts by weight of the fluorine-containing compound.

The use of the lubricant of the present invention is not limited to the use for a magnetic recording medium. [Magnetic Recording Medium] As described above, the magnetic recording medium of the present invention has a support, a magnetic layer formed on the support, and a layer containing the lubricant of the present invention. As the magnetic layer, for example, a coating type magnetic layer formed by applying a magnetic paint containing a magnetic powder and a binder on the non-magnetic support, or a physical layer such as sputtering, vacuum deposition or ion plating. A metal thin film type magnetic layer formed by a phase growth method (PVD method) can be used. In the coating type magnetic layer, the lubricant of the present invention is contained in the magnetic layer.
Among these magnetic layers, it is particularly preferable to use a metal thin film type magnetic layer in the present invention.

The metal thin film type magnetic layer will be described. Metals forming the magnetic layer include, for example, Fe, C
o, Ni and other metals, Co-Ni alloys, Co-P
t-based alloy, Co-Ni-Pt-based alloy, Fe-Co-based alloy, Fe-Ni-based alloy, Fe-Co-Ni-based alloy, Fe
-Co-B-based alloy, Co-Ni-Fe-B-based alloy, Co
-Cr-based alloys or alloys containing a metal such as Al are used. Further, these oxides, nitrides, carbides and the like are also used. In addition, an oxidizing gas is supplied during the formation of the metal thin film, and the surface of the metal thin film is
A protective layer made of an oxide film may be formed.

The magnetic layer may be composed of one metal thin film, or may be composed of two or more metal thin films. When the magnetic layer is composed of two or more metal thin films, the material of each metal thin film may be the same or different. The magnetic layer preferably has a total thickness of generally 500 to 5000 °.

As the support on which the magnetic layer is provided, a known non-magnetic support can be used without particular limitation. Specifically, known resins such as polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polycarbonate, polyamide, polyimide, polyamide imide, polysulfone, aramid, and aromatic polyamide; metals such as aluminum and copper; paper and the like are used. be able to. The form may be any of a film, tape, sheet, disk, drum and the like. Before providing the magnetic layer on the support, the surface of the support is previously subjected to corona discharge treatment in air and / or in vacuum,
Plasma treatment, easy adhesion treatment, heat treatment, dust removal treatment, bombardment treatment, and the like can also be performed. The preferred thickness of the support is 1 to 300 μm.

Further, a protective layer can be provided on the magnetic layer. In this case, the protective layer is generally made of carbon or carbide, nitride or oxide, in particular, diamond-like carbon, diamond, boron carbide,
It is preferably formed by forming a film of silicon carbide, boron nitride, silicon nitride, silicon oxide, chromium oxide, aluminum oxide, or the like. As the protective layer, it is particularly preferable to use a carbon thin film layer in an amorphous state, a graphite state, a diamond state, or a mixed state or a laminated state thereof. The thickness of the protective layer is not particularly limited, but is preferably 30 to 300 mm as a general thickness. The protective layer may be formed by any of a chemical vapor deposition (CVD) method and a PVD method. In the CVD method, in particular, ECR (Electron Cyclotr) using microwaves is used.
on Resonance) and a method using high frequency (RF) are effective. When the protective layer is formed by a CVD method,
The raw material may be any of gaseous, liquid and solid.

In the magnetic recording medium of the present invention, other layers can be provided, if necessary, in addition to the above protective layer. For example, an undercoat layer may be provided between the support and the magnetic layer to improve the adhesion between the two, or a surface of the support opposite to the surface on which the magnetic layer is formed. In addition, a back coat layer for improving running properties and durability of the magnetic recording medium can be provided.
In this case, the back coat layer may be any of a coating type and a metal thin film type, but is preferably a metal thin film type back coat layer. The metal thin film-type back coat layer is generally made of Al, Cu, Si, Fe, Mo, Mn, Zn, or the like, or an alloy, oxide, nitride,
It is formed by depositing a carbide or the like. Generally, the thickness of the back coat layer is preferably from 500 to 10,000 mm.

The magnetic recording medium of the present invention has a lubricating layer containing the above-described lubricant of the present invention. In the case of a metal thin film type magnetic layer, it is formed on the magnetic layer or on the magnetic layer. When a protective layer is provided, a lubricating layer is formed on the protective layer. The method for forming the lubricating layer is as described above, and the thickness of the lubricating layer is not limited, but is generally 5 to 80 °, preferably 5 to 40 °. Further, the lubricant of the present invention can be applied in the back coat layer or on the back coat layer as needed. With respect to the amount of the fluorine-containing compound to be attached to the back coat layer, the forming method, the additives, and the like, the description in detail regarding the magnetic layer side is similarly applied.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 <Production of fluorinated compound> A fluorinated compound (1a) was produced according to the following reaction formula.

[0031]

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66 g of the compound (1b) was dissolved in 500 ml of DMF, 1.2 equivalents of NaH was added thereto, and the mixture was heated to 60 ° C. After aging for 1 hour, 16 g of compound (1c) was gradually added dropwise, and the mixture was further stirred at 80 ° C. for 1 hour. After cooling, add water,
The mixture was separated with toluene and concentrated under reduced pressure to obtain 34 g of the compound (1a) (yield: 58%). Furthermore, as the compounds (1b) and (1c) in the above method, the compounds shown in Table 1 were used as the fluorine-containing compounds (2a) to (4a) shown in Table 1 respectively.
Was manufactured.

[0033]

[Table 1]

The reaction products were confirmed by infrared absorption spectroscopy (IR), nuclear magnetic resonance analysis (NMR) and mass spectrometry (FAB-MS). Table 2 shows the results.

[0035]

[Table 2]

Example 2 <Manufacture of Magnetic Recording Medium and Evaluation of Performance> (1) Manufacture of Magnetic Tape While introducing oxygen gas by continuous vacuum oblique deposition onto a 6.3 μm-thick PET film, Co-O was used. (Hc: 1560 Oe, Bs: 5900)
G). Next, on this magnetic layer, EC using microwave was used.
A DLC (diamond-like carbon) layer was formed to a thickness of 80 ° using benzene as a raw material by the R-CVD method.
On the back surface of the PET film, a back coat layer made of carbon black and a binder was formed by coating to a thickness of 0.4 μm. Next, each of the fluorine-containing compounds (1a) to (4a) obtained in Example 1 was dissolved in toluene to prepare a lubricant, and the amount of the lubricant (after drying) was 8 mg / m 2.
^The lubricant was applied on the above-mentioned DLC layer to form a lubricating layer. For comparison, the compounds shown in Table 1 were used as lubricants.

The Co—O-based magnetic layer obtained as described above,
The film on which the DLC protective layer, the fluorine-based lubricating layer and the back coat layer were formed was cut into a width of 8 mm, and was loaded into a cassette case to obtain an 8 mm video tape.

(2) Performance Evaluation The 8 mm video tape obtained above was subjected to 23 ° C., 50% RH (condition), 40 ° C., 80% RH (condition), 5 ° C., 50% RH.
Under each environment of (conditions), modified commercial Hi8mmVT
Still durability (time required for the output to decrease by 3 db) was measured using R, and the respective friction coefficients were measured under the same environment. Table 1 shows the results.

[0039]

[Table 3]

Example 3 The following fluorine-containing compounds A to J were synthesized according to Example 1,
Using these as a lubricant, an 8 mm video tape was produced in the same manner as in Example 2, and the same evaluation as in Example 2 was performed.
Table 7 shows the results.

[0041]

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[0042]

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[0043]

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[0044]

[Table 4]

[0045]

As described above, the novel fluorinated compound of the present invention has a fluoroalkyl group Rf and an alkenyl group R, but the fluoroalkyl group is exposed on the surface and contributes to a reduction in the surface energy of the alkenyl group. Exhibits good lubricity due to intermolecular interaction with alkenyl groups of other adjacent molecules. Further, the fluorine-containing compound of the present invention strongly adheres to the magnetic layer or the protective layer due to the presence of one or two polar groups in the molecule. Moreover, conventional perfluoropolyether-based lubricants are soluble only in expensive fluorine-based solvents, but the fluorine-containing compounds of the present invention are soluble in common hydrocarbon-based solvents such as toluene. The range of application can be expanded.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10M 105/54 C10M 105/54 105/56 105/56 G11B 5/71 G11B 5/71 5/72 5/72 // C10N 40 : 18 (72) Inventor Katsumi Endo 2606 Kabane-cho, Kaga-cho, Haga-gun, Tochigi Pref. In Kao Co., Ltd. (56) References JP-A-3-153645 (JP, A) JP-A-9-104881 (JP, A) JP-A-9-104882 (JP, A) JP-A-9-104883 (JP, A) JP-A 9-104884 (JP JP, A) JP-A-7-215903 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C07C 21/18 C07C 33/42 C07C 43/178 C07C 59/60 C07C 265 / 04 C10M 105/54 C10M 105/56

Claims (5)

(57) [Claims] 1. A fluorine-containing compound represented by the following general formula. Embedded image [Wherein, Rf: a fluoroalkyl group R: an alkenyl group having at least one double bond and optionally having a polar group] X, Y: Z ₁ does not -O- or present: polar group l: 0 integer greater than or equal 2. The number C ₁ and R of carbons of Rf in the above general formula
Fluorine-containing compound of the number of carbon atoms C ₂ is claim 1 wherein the C ₁ <C _2. 3. A lubricant containing the fluorine-containing compound according to claim 1. 4. A magnetic recording medium comprising a support, a magnetic layer formed on the support, and a layer containing the lubricant according to claim 3. 5. The magnetic recording medium according to claim 4, wherein the magnetic layer is a metal thin-film type magnetic layer, and a lubricant layer containing the lubricant is formed on the magnetic layer.