JPH06301967A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a metallic thin film type magnetic recording medium having an excellent running property, durability, and preservability. CONSTITUTION:In the recording medium having a ferromagnetic metallic thin film on at least one surface of a nonmagnetic substrate, a protective layer which contains a silane coupling agent having a >=6C alkyl group and fluorine compound which has a perfluoroalkyl group at one end of its molecule and alkyl group containing no fluorine at the other end is formed on the metallic thin film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film metal type magnetic recording medium excellent in running property, durability and storability.

[0002]

2. Description of the Related Art A lubricant for a magnetic recording medium such as a magnetic tape or a floppy disk is applied to the surface of a magnetic layer to improve lubricity and running durability between the magnetic recording medium and a head. Alternatively, in the case of photographic light-sensitive materials, it is applied on the surface of the light-sensitive material so that it can withstand even under severe conditions of use. Particularly, in the magnetic recording medium, the surface of the magnetic layer becomes smoother due to the higher recording density, the magnetic recording medium is used in various environments, and the recorded information is stored for several years to several decades. Therefore, running durability and storage stability under various environments are required, and conventional lubricants cannot exhibit sufficient effects.

Further, a camera-integrated video tape recorder and a small-sized video tape recorder are often used externally, and a magnetic recording medium is required to have a lubricating performance that can be used under a wide range of environmental conditions. Further, the thin film metal type magnetic layer is advantageous for high density recording, and the thin film metal type magnetic layer is expected to improve the magnetic recording density in future high definition, digitalization, etc. Since the thin film metal type magnetic recording medium is protected only by the layer, it is required to provide a lubricant capable of greatly improving the storability.

In a so-called metal thin film type magnetic recording medium in which a ferromagnetic thin film, which is expected as a magnetic recording medium for high density recording having excellent electromagnetic conversion characteristics, is formed on a non-magnetic support, an organic fluorine compound is used. It is known that it is effective to use it as a lubricant. It is well known that an organic fluorine compound containing a perfluoroalkyl group has a hydrophobic property as well as an oleophobic property, and exhibits a property as a surfactant even in water and oil. It also has the property of lowering the surface energy, and by utilizing these properties, an organic fluorine compound is applied to improve the slipperiness and lubricity of the material.

Further, a magnetic recording medium in which a silane coupling agent is used together with a fluorine-based lubricant is disclosed in JP-A-59-1.
No. 72159, the silane coupling agents include CH ₃ Si (OCH ₃ ) ₃ and (CH ₃ ) _3.
SiNHSi (OCH ₃ ) ₃ is disclosed. The alkyl group of these silane coupling agents has a short carbon chain such as a methyl group, and these are dipped in a solution and applied to the surface. Further, as the fluorine-based lubricant to be used in combination, CRYTOX 157FS / M manufactured by DuPont, which is a perfluoropolyether lubricant, and Fomblin Z manufactured by Montedison Co., Ltd. are disclosed, and as other lubricants, tetrafluoroethylene, Hexafluoropropylene, trichlorofluoroethylene, fluorinated alkyl esters, and those with hydroxyl groups, carboxyl groups, phosphoric acid, and sulfonic acid added to their ends are shown, and these lubricants are applied using Freon as a solvent. . Further, JP-A-2-2017727 discloses a magnetic recording medium using a silane coupling agent containing a fluorine-containing alkyl group, a fluorine-containing alkylamino group, etc. as a lubricant and a method for producing the same, but these are disclosed. Insufficient in terms of friction coefficient. In addition, JP-A 1-24059
No. 8 discloses CF ₃ (C) on a monolayer of a silane coupling agent having H ₂ N-phenyl- (CH2) _n-.
F _{2) k} (CH ₂₎ a magnetic recording medium formed with the compound represented by _j COOH is described.

Japanese Examined Patent Publication No. 19602/1993, JP-A-54-7
The No. _{9366, -SO 3 Na, -SO 3} K, -SO 3
Although a lubricant made of a fluorine-based hydrocarbon compound having H, —COOH, etc. is described, the μ value, still durability and storage stability are poor. In addition, JP-A-62-922
No. 27 describes coating a compound having a fluoroalkyl group and an aliphatic alkyl group onto a ferromagnetic metal thin film, but these compounds can be coated with isopropanol by introducing an alkyl group. But μ
Value, still durability, and storage stability were insufficient.

Further, Japanese Patent Laid-Open No. 64-72313 describes the use of a lubricant having Rf-Rh-X, and although the μ value is slightly improved, the Langmuir-Blodgett ( The monolayer film formed by the LB) film has poor productivity and is not practical, and has poor μ value, still durability, and storage stability, and its solubility in a hydrocarbon solvent is insufficient. Further, JP 58-100228 discloses is indicated lubricant having two chains bound to perfluoroalkyl group and an alkyl _{group, C 3 F 7 CH 2 CO} 2 - a lubricant double-stranded Although it is described that it is applied to a coating type magnetic recording medium, such a short chain length cannot be expected to have a sufficient reduction in the friction coefficient as a protective layer of a vapor deposition tape, and thin film metal type magnetic recording It has the drawback of being highly corrosive when applied to a medium and having a high coefficient of friction, and it requires the use of a fluorine-based solvent, and the lubricant itself is easily hydrolyzed and cannot withstand long-term storage. There is no such thing.

In addition to applying the above-mentioned lubricant to the magnetic recording layer, for example, perfluoroalkyl polyethers and their derivatives (JP-A-60-61918, JP-A-61-61).
107528, U.S. Pat. No. 3,778,308, Japanese Patent Publication No. 60-10368, U.S. Pat. No. 4,897,211).
It is described that, however, these fluorine-based organic compound lubricants have a low low-speed friction coefficient with the mating member with which the tape slides and are insufficient, and have a long shelf life such as sulfurous acid gas. With respect to acid gas corrosion, the magnetic layer is detached, and the magnetic recording medium cannot be practically used.
Also, fatty acids and fatty acid esters (Japanese Patent Publication No. 28-28
No. 367, Japanese Patent Publication No. 51-39081, Japanese Patent Publication No. 51-3
0981, JP-A-56-80828, JP-A-61-
No. 24017) has a high high-speed friction with a magnetic head and is insufficient, and is also insufficient in corrosive acid gas such as sulfurous acid gas.

Further, many of the above lubricants are
When applied on the magnetic recording layer, the solubility in ordinary hydrocarbon-based organic solvents is poor, and many are soluble only in fluorine-based organic solvents. Organic solvents must be used. Fluorine-based organic solvents are expensive and have serious problems in protecting the natural environment such as substances that cause the destruction of the ozone layer. In addition, they adversely affect manufacturing equipment and worsen the working environment, which is a major problem. Had.

The present invention is a thin film metal obtained by vapor deposition or sputtering which dissolves in an ordinary hydrocarbon type organic solvent, overcomes the drawbacks of using a fluorine type solvent, and dramatically improves the recording density particularly in a high density recording medium. It imparts runnability, durability, and storability to the medium.

[0011]

The present invention is directed to alcohols such as methanol, ethanol and isopropanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, ketones such as cyclohexanone, hydrocarbon solvents such as toluene, ethyl acetate and butyl acetate. Esters of
Dissolved in a general-purpose solvent such as ethers such as tetrahydrofuran, for the purpose of providing a magnetic recording medium to which a layer made of a lubricant made of a fluorine-containing organic compound which does not need to use a fluorine-containing organic solvent is firmly adhered, Further, the magnetic recording medium comprising a metal thin film capable of dramatically improving the recording density by vapor deposition, sputtering, etc.
The present invention provides a magnetic recording medium having durability and storability.

Another object of the present invention is to provide a magnetic recording medium having sufficient running property and durability even under a wide range of outdoor environment conditions.

[0013]

In a magnetic recording medium having a ferromagnetic metal thin film on at least one surface of a non-magnetic support, a silane coupling agent having an alkyl group having 6 or more carbon atoms on the ferromagnetic metal thin film. And a fluorine-containing compound having a perfluoroalkyl group at one end of the molecule and a fluorine-free alkyl group at the other end of the molecule.

A magnetic recording medium in which the fluorine-based compound is at least one selected from compounds having a carbon-carbon unsaturated bond represented by the following general formulas (1) and (2).

[0015]

[Chemical 3]

However, Rf ¹ and Rf ² are CF ₃ CF ₂
(CF ₂ ) _N (CH ₂ ) _M or (CF ₃ ) ₂ CF
(CF ₂ ) _N (CH ₂ ) _M , which may be the same or different, n is 1 to 10 and m is 1
To 20 and n + m is 6 to 30. Y ¹ and Y ²
Is -O-, -OCO-, -COO-, -NHCO-,
-CONH-, which may be the same or different from each other.

R ¹ is ═CH ₂ , ═CH (C
H ₂ ) _K CH ₃ , = CHCH = CH ₂ , and k is 0
To 2. R ² is R ² is absent in the case of H or a hydrocarbon group, and the carbon to which R ² is attached has a double bond. R ³ represents H or a hydrocarbon group which may have a double bond. A and B are (CH ₂ ) _K , k is 0 to 2, and a is a number of 1 or more. In addition, Rf ¹ , Rf ² , Y ¹ , Y ² , R ¹ , R ² , R ³ ,
k, n and m may be the same or different and may be cis type or trans type.

[0018]

[Chemical 4]

However, Rf ¹ , Rf ² and Rf ³ are CF
₃ CF ₂ (CF ₂ ) _N (CH ₂ ) _M or (CF ₃ ) ₂
CF (CF ₂ ) _N (CH ₂ ) _M , which may be the same or different from each other, and n is 1 to 10,
m is 1 to 20, and n + m is 6 to 30. Y ¹ , Y
² and Y ³ are -O-, -OCO-, -COO-,-.
NHCO- and -CONH-, which may be the same or different from each other. R ⁴ represents H or a hydrocarbon group which may have a double bond. R ⁵ is R ⁵ is absent in the case where carbon H or a hydrocarbon group, and R ⁵ bonded have a double bond. R ⁶ represents H or a hydrocarbon group which may have a double bond.
A, B, and X are (CH ₂ ) _K , where k is 0 to 2
And b is 0 or a number of 1 or more. Also, R
f ¹ , Rf ² , Rf ³ , Y ¹ , Y ² , Y ³ , A, B,
X, R ⁴ , R ⁵ , R ⁶ , k, n and m may be the same or different and may be cis type or trans type.

Further, in the general formula (1) or (2), it is particularly preferable that n is from 2 to 8, and if it is too large, the solubility in a hydrocarbon solvent is lowered, and if it is too small, the friction coefficient is large. The lubricity deteriorates. Further, it is particularly preferable that m is from 2 to 11, and if it is too small, the solubility in a hydrocarbon solvent decreases, and if it is too large, the coefficient of friction increases and lubricity deteriorates. Further, n + m is preferably 6 to 19, and if it is too large, the solubility in a hydrocarbon solvent decreases, and if it is too small, the friction coefficient increases and the lubricity deteriorates. Y ¹ , Y ² and Y ³ are especially -OCO- or -C.
OO- are preferred, -S -, - SO -, - SO 2 - , etc. are not preferred because especially corrosive. R ¹ ,
^{R 2, R 3, R 4} , R 5, R 6 are all those also becomes small friction coefficient of becomes larger number of carbon atoms greater are preferred.

Further, the fluorine-based compound is represented by the following general formula (3)
~ At least one selected from the compounds represented by (6)
Is also one type of magnetic recording medium. Rf (CF₂ )_n(CH₂ )_mOCO (CH₂ )_pCH₃(3) Rf (CF₂ )_n(CH₂ )_mCOO (CH₂ )_pCH₃ (4) Rf (CF₂ )_n(CH₂ )_mO (CH₂ )_pCH₃ (5) Rf (CF₂ )_n(CH₂ )_m(CH₂ )_pCH₃ (6) In these fluorine compounds, n is 3 or more and 9 or less.
It is preferable that it is 6 or more and 9 or less.
preferable. If n is 2 or less, the still durability is insufficient.
Is not preferable, and if it is 10 or more, the solubility becomes poor.
And the μ value becomes high, which is not preferable. Well
In addition, m is preferably 0 or more and 11 or less, and 2 or more
It is more preferably 6 or less. m is 12 or more
And the μ value becomes high, which is not preferable. Also, n + m is 6
It is preferably 20 or more and 20 or less, and 8 or more and 16 or less
More preferably. μ value when n + m is 5 or less
Is high and the storage stability is poor, which is not desirable.
If it is 21 or more, the μ value becomes high, which is preferable.
No Also, p is preferably 5 or more and 20 or less.
More preferably, it is 6 or more and 16 or less. p is 4
If it is below the range, durability is deteriorated, which is not preferable.
The above value is not preferable because the μ value becomes high. Furthermore
And Rf is CF₃-, (CF₃)₂Be CF-
This is good.

The silane coupling agent applied on the magnetic layer is at least one selected from the alkoxysilane coupling agents represented by the following general formula (7). The carbon number of the alkyl group of the general formula (7) C _n H _{2n + 1} Si (OC _m H _{2m + 1} ) ₃ silane coupling agent is 6 or more 2
It is preferably 0 or less, particularly preferably 8 or more and 18 or less. Further, m is preferably 1 or 2, that is, the alkoxy group is preferably a methoxy group or an ethoxy group.
As such a silane coupling agent, C ₁₀ H ₂₁
Si (OCH ₃ ) ₃ (eg Shin-Etsu Chemical KBM310
3), C ₆ H ₁₃ Si (OCH ₃ ) ₃ (for example, Shin-Etsu Chemical LS3130), C ₄ H ₉ Si (OCH ₃ ) ₃ (for example, Shin-Etsu Chemical LS1180), and C ₈ H ₁₇ Si.
(OC ₂ H ₅ ) ₃ , C ₁₈ H ₃₇ Si (OC ₂ H ₅ ) ₃ , C
_{18 H 37 Si (CH 3)} (OC 2 H 5) 2, C 12 H 25 Si
(CH ₃ ) (OC ₂ H ₅ ) ₂ , C ₈ H ₁₇ Si (OC
_{H 3) 3, C 12 H} 25 Si (OCH 3) 3, C 14 H 29 Si
(OCH ₃ ) ₃ , C ₁₈ H ₃₇ Si (OCH ₃ ) ₃ , C ₆ H
₁₃ Si (OC ₂ H ₅ ) ₃ , C ₁₀ H ₂₁ Si (OC ₂ H ₅ )
₃ , C ₁₄ H ₂₉ Si (OC ₂ H ₅ ) ₃ , C ₁₂ H ₂₅ Si (C
_{H 3) (OCH 3) 2} , C 12 H 25 Si (CH 3) (OC
₂ H ₅ ) ₂ , C ₁₈ H ₃₇ Si (CH ₃ ) (OCH ₃ ) ₂ ,
_{C 18 H 37 Si (CH 3} ) (OC 2 H 5) 2, C 12 H 25 S
i (C ₂ H ₅ ) (OCH ₃ ) ₂ , C ₁₂ H ₂₅ Si (C ₂ H
_{5) (OC 2 H 5)} 2, C 10 H 21 Si (O-isoC 3
_{H 7) 3, C 5 H} 11 (C 2 H 5) Si (OCH 3) can be exemplified ₃ or the like.

A solution prepared by dissolving the silane coupling agent in at least one hydrocarbon-based organic solvent selected from acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol and isopropanol is used as the ferromagnetic metal. A solution prepared by coating the thin film on a thin film and then dissolving the fluorine-containing compound in at least one hydrocarbon-based organic solvent selected from acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, and isopropanol is used. It is a magnetic recording medium coated on a magnetic metal thin film.

The ferromagnetic metal thin film is formed by a vacuum film forming method such as a vacuum vapor deposition method, an ion plating method, a sputtering method and a CVD method. The film is formed by a single layer, a parallel type multilayer, a non-parallel type multilayer, or the like. Further, as the metal material used, in addition to metals such as iron, cobalt and nickel, cobalt-nickel alloys, cobalt-chromium alloys,
Examples include cobalt-based alloys such as cobalt-platinum alloys and iron-cobalt alloys. In addition, Co-O-based and CoNi-O-based ferromagnetic metal thin films deposited with a cobalt or cobalt-nickel alloy as an evaporation source in a slight oxygen atmosphere have a good balance of magnetic characteristics, electromagnetic conversion characteristics, weather resistance, and durability. Good and more preferable.

The non-magnetic support has a thickness of 5 μm to 15 μm.
In addition to polyethylene terephthalate, polyethylene naphthalate, polyimide, polyamide, polyamide polyimide, etc., a film made of synthetic resin such as polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride is preferable, and the magnetic layer has a thickness of 0.1 to 0. It is preferably 3 μm. Further, these magnetic layers may have a multilayer structure of two or more layers.

Further, in order to improve the durability, running property, etc. of the magnetic recording medium, it is preferable to impart an appropriate surface roughness to the surface of this non-magnetic support. For example, a method known in this technical field such as a wrinkle-shaped protrusion, a mountain-shaped protrusion, and a granular protrusion can be adopted.

Further, the magnetic recording medium is provided with a back layer and an undercoat layer for the magnetic layer, which is more advantageous in running property and durability. The metal thin film magnetic layer to a plasma CVD or the _{like, CH 4, C 2 H 6} , C 3 H 8, C 4 H 10 , etc. of an _{alkane, CH 2 = CH 2, CH} 3 CH = CH 2 or the like alkene, CH≡CH The lubricant of the present invention can be applied by coating or the like on a thin film metal recording medium provided with a carbon film obtained by supplying a volatile compound such as alkyne or the like.

Further, other lubricant may be used in combination with the lubricant comprising the organic fluorine compound of the present invention. For example perfluoropolyether CF ₃ represented by the following _{- (CFRfCF 2 -O) -nCF 2} CF 3 or the end OH, those that are modified with COOH or the like is used. Here, Rf is CF ₃ or F, and the molecular weight is 1000 to 20000, preferably 2500 to 100.
00 is mentioned. Specifically, K manufactured by DuPont
Examples thereof include RYTOXK143AZ, K157FSL, FOMBLIN AM2001 manufactured by Montefluos Co., and DEMNUMSY manufactured by Daikin Industries.

The solution is applied to the surface of the magnetic layer.
As a coating method, a solvent is dissolved in an organic solvent and a coil bar or the like is used. The coated surface may be on the magnetic layer side or the back layer side. At that time, when the compound of the present invention is applied to an ordinary magnetic recording medium, it is applied as a solution on the surface of the magnetic layer. The coating amount for the cyan coupling agent is preferably 0.2~5mg / m ^2, and particularly preferably 0.5 to 2 mg / m ^2. Further, the coating amount of the lubricant containing a fluorine-based compound is preferably ¹ to 30 mg / m ² , and 2 to
It is more preferably 10 mg / m ² . Further, since these compounds are dissolved in at least one hydrocarbon solvent selected from usual acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol and isopropanol, application without using a fluorine-based organic solvent is possible. Then, the magnetic recording medium can be manufactured by drying. Since it can be dissolved in a hydrocarbon solvent, there is no risk of causing problems such as environmental pollution due to the use of a CFC solvent unlike conventional fluorine compounds.

[0030]

In a magnetic recording medium having a ferromagnetic metal thin film on at least one surface of a non-magnetic support, a silane coupling agent having an alkyl group having 6 or more carbon atoms on the ferromagnetic metal thin film and one end of a molecule. Is a perfluoroalkyl group, and the other end has a protective layer containing a fluorine-based compound which is an alkyl group containing no fluorine, and the protective layer of the present invention has a coupling agent on the magnetic layer surface. Adsorption reaction, the alkyl group of the coupling agent interacts with the hydrocarbon group of the fluorine-based lubricant with appropriate strength,
The magnetic layer and the silane coupling agent form a strong bond to form a surface protection layer, and the fluorine-based lubricant and the coupling agent combine due to the interaction between the hydrocarbon groups possessed by both to provide a low friction surface protection. While the layer is obtained, it can be applied by dissolving it in a usual organic solvent without using a fluorine-based organic solvent.

[0031]

【Example】

Examples and Comparative Examples A cobalt-nickel magnetic film having a film thickness of 150 nm was obliquely deposited on a polyethylene terephthalate film having a thickness of 10 μm,
A magnetic metal thin film layer was provided. An electron beam evaporation source is used as an evaporation source, and a cobalt-nickel alloy (Co:
90% by weight Ni: 10% by weight), oxygen was introduced, and the incident angle was 50 at a pressure of 6.7 × 10 ⁻³ N / m ² .
Diagonal vapor deposition was performed so that the temperature was constant. On the obtained magnetic metal thin film layer, the silane coupling agent and the lubricant shown in Table 1 and Table 2 were applied with a coil bar and dried, and a back layer was provided to slit a width of 8 mm to prepare a magnetic tape. Comparative examples are shown in Tables 1 and 2 together with the evaluation results obtained by the following evaluation methods. In sample number (ratio)
Shows a comparative example.

[Evaluation Method] Measurement of Friction Coefficient The obtained magnetic tape and a stainless steel pole were brought into contact with each other at a winding angle of 180 ° with a tension (T ₁ ) of 20 g, and the magnetic tape was run at a speed of 3.3 cm / sec. Measure the tension (T ₂ ) required to make the magnetic tape
The friction coefficient μ was determined. μ = 1 / π · ln (T ₂ / T ₁ ) Friction coefficient is 100 pass, 60 ℃ 90% RH
The samples stored in the above environment for 10 days were measured at 23 ° C. and 70% RH for 100 passes.

Still Durability Measurement The still durability was measured by using an 8 mm VTR (FUJIX-FX-100 type manufactured by Fuji Photo Film Co., Ltd.) without reproducing the still limit mechanism and reproducing the image in the still state. The time until it disappeared was measured and evaluated.
Still durability was measured immediately after preparation at 5 ° C. and 10% RH.

Evaluation of storability It was stored in the following environment, and the surface of the magnetic layer after storage was visually and visually observed. Temperature / humidity: 60 ° C, 90% RH Number of storage days: 10 days Evaluation criteria ○: No corrosion is observed when the surface of the magnetic layer is observed under a 200 × optical microscope. △ ... Corrosion is observed as above, but it is magnetic by visual observation. A metallic luster on the surface of the layer is observed ..... There is no metallic luster on the surface of the magnetic layer when observed with the naked eye.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

EFFECTS OF THE INVENTION A high-density magnetic recording medium is realized by providing a protective layer having a high degree of storability, runnability, and durability, which cannot be obtained by a conventionally known lubricant. This is the effect of the coupling agent having the specific structure disclosed in the present invention used in combination with the specific fluorine-based lubricant. In the protective layer of the present invention, the coupling agent undergoes an adsorption reaction on the surface of the magnetic layer, the alkyl group of the coupling agent interacts with the hydrocarbon group of the fluorine-based lubricant at an appropriate strength, and the outermost layer has a perfluoro group. Turn the alkyl chain. As a result, the magnetic layer and the coupling agent form a strong bond to form a surface protective layer, and the fluorine-based lubricant and the coupling agent combine due to the interaction between the hydrocarbon groups, and the running of the head, guide pole, etc. It is considered to act so as to reduce friction (shear stress) when sliding with a system member. Further, the fluorine atom on the outermost surface reduces the surface energy and effectively works to reduce friction, and protects the magnetic layer by the water-repellent effect even during storage under high humidity conditions. It is considered that the silane coupling agent is effective in improving the storage stability by coating the chemically active sites of the magnetic layer.

Claims (5)

[Claims] 1. A magnetic recording medium having a ferromagnetic metal thin film on at least one surface of a nonmagnetic support, wherein one of a silane coupling agent having an alkyl group having 6 or more carbon atoms and a molecule on the ferromagnetic metal thin film. A magnetic recording medium having a protective layer containing a fluorine-based compound having a perfluoroalkyl group at the terminal and a fluorine-free alkyl group at the other terminal. 2. The fluorine-based compound is at least one selected from compounds having a carbon-carbon unsaturated bond represented by the following general formulas (1) and (2). 1. The magnetic recording medium according to 1. [Chemical 1] However, Rf ¹ and Rf ² are CF ₃ CF ₂ (CF ₂ ) _N
(CH ₂ ) _M or (CF ₃ ) ₂ CF (CF ₂ )
_n (CH ₂ ) _M , which may be the same or different, n is 1 to 10, m is 1 to 20,
n + m is 6 to 30. Y ¹ and Y ² are -O
-, -OCO-, -COO-, -NHCO-, -CON
H-, which may be the same or different from each other. R ¹ is ═CH ₂ , ═CH (CH ₂ ) _K
CH ₃ , = CHCH = CH ₂ , and k is 0 to 2
Is. R ² is R ² is absent in the case of H or a hydrocarbon group, and the carbon to which R ² is attached has a double bond. R ³ represents H or a hydrocarbon group which may have a double bond. A and B are (CH ₂ ) _K , k is 0 to 2, and a is a number of 1 or more. Also, R
f ¹ , Rf ² , Y ¹ , Y ² , R ¹ , R ² , R ³ , k,
n and m may be the same or different, cis type,
Either of the transformer type may be used. [Chemical 2] However, Rf ¹ , Rf ² and Rf ³ are CF ₃ CF ₂ (C
F ₂ ) _N (CH ₂ ) _M or (CF ₃ ) ₂ CF (CF ₂
) _N (CH ₂ ) _M , which may be the same or different, n is 1 to 10 and m is 1 to 2
0 and n + m are 6 to 30. Y ¹ , Y ² and Y ³
Is -O-, -OCO-, -COO-, -NHCO-,
-CONH-, which may be the same or different from each other. R ⁴ represents H or a hydrocarbon group which may have a double bond. R ⁵ is R ⁵ is absent in the case where carbon H or a hydrocarbon group, and R ⁵ bonded have a double bond. R ⁶ represents H or a hydrocarbon group which may have a double bond. A, B, and X are (CH ₂ ) _K , k is 0 to 2, and b is 0 or a number of 1 or more. In addition, Rf ¹ , Rf ² , R
f ³ , Y ¹ , Y ² , Y ³ , A, B, X, R ⁴ , R ⁵ , R
⁶ , k, n and m may be the same or different,
Either cis type or trans type may be used. 3. The fluorine-based compound is represented by the following general formula (3):
The magnetic recording medium according to claim 1, wherein the magnetic recording medium is at least one selected from compounds represented by (6) to (6). Rf (CF ₂ ) _N (CH ₂ ) _M OCO (CH ₂ ) _P CH ₃ (3) Rf (CF ₂ ) _N (CH ₂ ) _M COO (CH ₂ ) _P CH ₃ (4) Rf (CF ₂ ) _N (CH ₂ ) _M O (CH ₂ ) _P CH ₃ (5) Rf (CF ₂ ) _N (CH ₂ ) _M (CH ₂ ) _P CH ₃ (6) where n is 3 to 9, m is 0 to 11, n + m is 6 to 20 p is 5 to 20, Rf is CF ₃ −, (CF ₃ ) ₂ CF−. 4. The magnetic material according to claim 1, wherein the silane coupling agent is at least one selected from the alkoxysilane coupling agents represented by the following general formula (7). recoding media. Formula _{(7) C n H 2n +} 1 Si (OC m H 2m + 1) 3 where, n is 6 to 20. m is 1 to 4. 5. A solution prepared by dissolving the silane coupling agent in at least one hydrocarbon organic solvent selected from acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, and isopropanol, A solution prepared by coating on a magnetic metal thin film, and then dissolving the fluorine-based compound in at least one hydrocarbon-based organic solvent selected from acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, and isopropanol. The magnetic recording medium according to any one of claims 1 to 4, wherein the magnetic recording medium is coated on the ferromagnetic metal thin film.