JPH1112212A - Fluorine-containing compound, and magnetic recording medium using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorine-containing compound low in dustability and high in thermal stability, and to provide a magnetic recording medium containing the compound. SOLUTION: This fluorine-containing compound has an oxyethylene site of the formula [X is a group containing an acyclic oxyethylene chain but not containing an amino group; (m) is 1 or 2; Rf is a perfluoropolyoxyalkyl chain having an average mol.wt. of >=800 or a perfluoropolyoxyalkylene chain]. The magnetic recording medium has at least one magnetic layer on a nonmagnetic support. Therein a film containing the fluorine-containing compound of the formula (1) as the outermost layer is disposed on the surface of the magnetic layer or a protecting layer disposed on the outside of the magnetic layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorine-containing compound having an oxyethylene moiety in a molecule and a magnetic recording medium using the same as a surface modifier, and more particularly to an improvement in sliding durability of the magnetic recording medium. And a low-scattering surface modifier.

[0002]

2. Description of the Related Art In order to increase the recording density of a magnetic disk drive, the distance between a head and a disk tends to be reduced. In addition, the number of rotations of a disk has been increasing in order to perform reading and writing at high speed. For this reason, the chances of contact between the head and the disk are increased, and the sliding condition of the disk is expected to be more severe than in the past because the contact is performed at a higher speed. In order to prevent abrasion of the magnetic layer, the lubricant used for the outermost layer of the magnetic disk has been improved.

[0003] As such a lubricant, for example, a fluorine-containing compound such as a compound having a piperonyl group at both ends of a perfluorooxyalkylene chain (JP-A-61-4727) is known. By applying these to the surface of the magnetic disk, the lubricity of the surface is improved and the wear of the magnetic layer can be considerably suppressed.

[0004] These lubricants are gradually scattered by sliding with the head. This is considered to be due to physical scraping by sliding or volatilization by thermal energy generated by sliding. Therefore, when the disk is used for a long time, the amount of the lubricant decreases from the surface of the disk, or in some cases, the lubricant disappears. Therefore, a lubricant having low scattering properties has been desired.

As such a lubricant, Japanese Patent Application Laid-Open No. 8-36741
And JP-A-8-36742 disclose a fluorine-containing crown ether compound in which an alkyl chain, a perfluorooxyalkyl chain, etc., and a crown ether are bonded by an amine bond. However, there is a problem that such a compound having an amine bond is liable to absorb moisture, thereby easily causing a change in lubrication characteristics.

The crown ether ring is more easily thermally decomposed than a non-cyclic oxyethylene chain (eg, tetraethylene glycol, polyethylene glycol, etc.). This is presumed to be due to the fact that the oxyethylene chain is distorted due to being cyclic.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluorine-containing compound having low scattering property and high thermal stability, and a magnetic recording medium using the same.

[0008]

The present inventors have studied various fluorine-containing compounds having a perfluorooxyalkylene chain or a perfluorooxyalkyl chain, and as a result, have found that a given fluorine-containing compound having an oxyethylene moiety in the molecule can be obtained. Has low scattering properties, high thermal stability, little change in lubricating properties, and is suitable as a surface modifier for magnetic recording media and the like, and completed the present invention.

That is, the present invention provides the following general formula (1):

[0010]

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(Wherein -X is a group containing an acyclic oxyethylene chain, and -X does not contain an amino group.
Is 1 or 2. Rf is a perfluoropolyoxyalkyl chain or a perfluoropolyoxyalkylene chain having an average molecular weight of 800 or more. ) A fluorine-containing compound having an oxyethylene moiety represented by the following general formula (2):

[0012]

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-Z is a linear or branched alkyl group having 1 to 16 carbon atoms, or COR (R represents a linear or branched alkyl group). n is an integer from 0 to 7. m is 1 or 2. Rf is a perfluoropolyoxyalkyl chain or a perfluoropolyoxyalkylene chain having an average molecular weight of 800 or more. ) A fluorine-containing compound having an oxyethylene moiety represented by the following general formula (3):

[0014]

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(Wherein -Z is a linear or branched alkyl group having 1 to 16 carbon atoms or COR (R represents a linear or branched alkyl group). N is an integer of 0 to 7. m. Is 1 or 2. Rf is a fluorine-containing compound having an oxyethylene moiety represented by a perfluoropolyoxyalkyl chain or a perfluoropolyoxyalkylene chain having an average molecular weight of 800 or more.

The present invention also relates to a magnetic recording medium having at least one magnetic layer on a non-magnetic support, wherein the magnetic layer or a protective layer provided outside the magnetic layer is provided on the surface of the magnetic layer. A magnetic recording medium having a film containing the above-mentioned fluorine-containing compound as an outermost layer.

Further, the present invention provides that the nonmagnetic support comprises a soda lime glass containing sodium ions or potassium ions, wherein the total content of the sodium ions and the potassium ions is at least 5 wt%. It is a magnetic recording medium characterized by the following.

The fluorine-containing compound of the present invention is a fluorine-containing compound having an oxyethylene moiety. It is considered that the presence of such a portion reduces the volatility and ensures sliding for a long period of time.

In the case of a magnetic recording medium, the film containing these fluorine-containing compounds is provided as a lubricating layer for improving the lubricity between the medium and the head. Therefore, a film thickness of 30
nm or less is desirable. This is because if the film is too thick, the coefficient of static friction between the medium and the head may increase.
In order to form such a thin film, a method of dissolving a fluorine-containing compound in various solvents and applying the solution is preferable in that the thickness of the film is easily controlled. After coating, the method of post-treatment differs depending on the boiling point and heat of evaporation of the solvent used, but it is necessary to remove the used solvent by drying at normal temperature or slightly under normal temperature or under reduced pressure. Become. At this time, if a solvent having a large heat of evaporation is used, moisture in the air may be easily taken into the film. Further, it is desirable to volatilize as quickly as possible at normal temperature and normal pressure after application, in order to improve workability and to prevent moisture and the like in the air from being taken into the film as much as possible during drying. However, if the boiling point is too low, the solvent is likely to evaporate, which may make it difficult to control the concentration of the fluorine-containing compound. Therefore, it is preferable that the solvent used has a small heat of evaporation (50 cal / g or less) and a boiling point of about 50 to 110 ° C.

Rf represents a perfluoropolyoxyalkyl chain or a perfluoropolyoxyalkylene chain having an average molecular weight of 800 or more. Rf 'represents a perfluoropolyoxyalkyl chain. If the molecular weight of the perfluoropolyoxyalkyl chain or perfluoropolyoxyalkylene chain is too low (less than 800), the solubility in a solvent having a perfluoroalkane structure tends to decrease. Therefore, the molecular weight is desirably 800 or more. In order to further improve the solubility in the above-mentioned solvent, it is desirable to increase the molecular weight of Rf and Rf 'as much as possible. Therefore, if possible, it is desirable that the number is 2000 or more. As a reagent used for introducing a perfluoropolyoxyalkyl chain or a perfluoropolyoxyalkylene chain, Krytox manufactured by DuPont [repeating unit is-(CF (CF ₃ ) CF ₂ O) _α- ], manufactured by Ausimont Fomblin [The repeating unit is-(CF (CF ₃ ) CF
₂ O) _α- (CF ₂ O) _β- , or
_{- (CF 2 CF 2 O)} α - (CF 2 O) β -], manufactured by Daikin Industries, Ltd. of DEMNUM [recurring units - (CF ₂ CF ₂ CF
₂ O) _α- ] (α and β represent the number of repeating units in the molecule). Of these materials, those having a carboxyl group at the terminal are formed by forming an amide bond or an ester bond, and those having a hydroxyl group at the terminal are formed by forming an ether bond, an ester bond, or the like. It becomes possible to obtain a fluorine-containing compound.

M represents the number of moieties bonded to the perfluoropolyoxyalkyl chain or the perfluoropolyoxyalkylene chain in the molecule of the fluorine-containing compound of the present invention. It is 1 for a perfluoropolyoxyalkyl chain, and 1 or 2 for a perfluoropolyoxyalkylene chain.

In the formula (1), -X is a group containing an oxyethylene chain. Specific examples of -X include those shown in the formulas (2) and (3). Equation (2) and (3)
Specific examples of the formula are shown below.

-Y- represents a perfluoropolyoxyalkyl chain or a binding site between a perfluoropolyoxyalkylene chain and a residue having an oxyethylene chain. As this bond, an amide bond (in the case of formula (2), -Y- is -C
_{ONHCH 2 CH 2 -, (3} ) in the case of formula -CON <),
Ether bond (-Y- is -CH ₂ -), ester bonds (-Y- is -CO-), and the like.

N represents the number of ethyleneoxy moieties. When the fluorine-containing compound of the present invention is applied to a metal surface or a magnetic recording medium surface, the adsorptivity tends to increase as the number of ethyleneoxy sites increases. However, if the amount is too large, the solubility in a solvent having a perfluoroalkane structure tends to decrease. The solubility tends to decrease as the number of ethyleneoxy moieties in the molecule increases. Therefore, when the molecular weights of Rf are the same, the structure of formula (3) tends to have lower solubility than the structure of formula (2). Rf is an average molecular weight of 80
0 and m are 2, the structure of the formula (3) and Z described later has 16 carbon atoms.
When n is 8 or more, the compound is not completely dissolved in a solvent having a perfluoroalkane structure, and partially insoluble components are observed (the higher the molecular weight of Rf, the more m Is smaller, and the smaller the carbon number of Z, the higher the solubility in a solvent having a perfluoroalkane structure.)

-Z represents a residue at the terminal of the acyclic polyether. For the bond between the terminal residue and the ethyleneoxy moiety, a bond such as an ether tends to have a higher adsorptivity to a metal or a magnetic recording medium than a bond having a carbonyl moiety such as an amide or an ester. . When -Z is hydrogen, the solubility in a solvent having a perfluoroalkane structure is low. Further, the solubility in organic solvents such as methylene chloride is low. In order to improve the solubility in these solvents, it is desirable to use a linear or branched alkyl group such as a methyl group or an ethyl group, or COR (R is a linear or branched alkyl group). The linear or branched alkyl group preferably has 1 to 16 carbon atoms. Average molecular weight of Rf 800,
In the case of m = 2, n = 7 and the structure of the formula (3), if the carbon number is 17 or more, fine irregularities may appear on the surface of the magnetic recording medium when applied to the surface (where Rf When the average molecular weight is increased, fine irregularities are less likely to occur even when the number of carbon atoms in -Z is increased.Specifically, when the average molecular weight of Rf is 4000, even when the number of carbon atoms in -Z is 20, fine irregularities are hardly observed. I can't.) Therefore -Z is 1 to 1
A carbon number of 6 is desirable. Also, when -Z is COR, -Z
Has preferably 1 to 16 carbon atoms for the same reason as the above-mentioned linear or branched alkyl group. However, when -Z is large, the occurrence of fine irregularities can be avoided by increasing the average molecular weight of Rf as described above.

The use of the fluorine-containing compound of the present invention includes:
Use as a surface modifier for modifying the surface of various media is mentioned. Specifically, lubrication, water repellency,
Improvement of waterproofness, prevention of adhesion of dust and dust, and the like can be mentioned. Applications include lubricants on the surface of magnetic disks, bearings, various gears, or radiating fins for air conditioners, various indoor and outdoor antennas such as VHF / UHF antennas and parabolic antennas for televisions, power transmission lines and telephone wires. Various cables, such as skis, snowboards, diving suits, skiwear, etc., the outside of aircrafts and ships, the outer walls of buildings, etc., as a water repellent, waterproofing agent, or charts, pictures, photographs, posters And the like, and an agent for preventing adhesion of dust and dirt on the surface of the like.

As a method of using the fluorine-containing compound of the present invention, a method of dissolving or suspending the compound in various solvents and applying the liquid to a medium can be mentioned. By evaporating the used solvent, the fluorine-containing compound layer is formed. In this case, care must be taken because some solvents may dissolve the medium surface.

Next, the magnetic recording medium of the present invention will be described. The magnetic recording medium of the present invention is used as an external memory of a computer, a word processor, and the like, and includes a hard disk device, a floppy disk, and the like. The size of the disc is, for example, about 1 inch to 14 inches. 1 for hard disk drive
One to several discs are stacked to ensure a large recording capacity. The structure of the disk is a substrate (Al
Metal alloys, ceramics such as glass, or organic polymer compounds such as polycarbonate and polystyrene),
Magnetic layer (alloy or oxide mainly composed of Fe, Co, Ni, etc.), protective layer (carbon, SiC, SiO
₂ ) and a film containing at least one fluorine-containing compound of the present invention. If necessary, a new layer (for example, a complex of Ni, Cr, and Zn, an oxide, and the like) may be used to improve the adhesion between the substrate and the magnetic layer or between the magnetic layer and the protective layer. The provision of a phosphorus-based metal complex or the like is not particularly limited.

The film formed on the protective layer of the magnetic recording medium of the present invention preferably has a thickness of 30 nm or less. This is because if the film is too thick, the coefficient of static friction acting between the head and the disk may increase. In order to form such a thin film, a method of dissolving a material for forming the film in some solvent and applying the solution on the protective layer is preferable in that the thickness of the film is easily controlled. After coating, the method of post-treatment varies depending on the boiling point and heat of vaporization of the solvent used, but it is necessary to remove the used solvent by drying at room temperature, or slightly heating, or under normal pressure or reduced pressure. Become. At this time, if a solvent having a large heat of vaporization is used, moisture in the air may be easily taken into the film.
Therefore, the solvent used is preferably a solvent having a small heat of vaporization.

The substrate serving as the support of the magnetic recording medium of the present invention is a soda-lime glass (sodium or potassium content is as large as 5 to 20 wt% as compared with ordinary glass for improving the mechanical strength, etc.). If it is less than 5 wt%, practically sufficient hardness as a magnetic recording medium cannot be obtained, and if it exceeds 20 wt%, toughness is reduced and it is easy to be damaged by a small impact.)
May reach the film containing the fluorine-containing compound through the magnetic layer and the protective layer. Alkali metals are usually added to glass in the form of oxides, so most of the hydroxides (NaOH and K) are used to reach the film containing the fluorine-containing compound.
OH). Since these are strong bases, fluorinated compounds that are weak in basicity may be decomposed. Even if the transfer of alkali metal (ion) occurs as described above, the ethyleneoxy moiety of the compound of the present invention is hardly decomposed under basic conditions since it is an ether bond, and -Y- is an amide or ether bond. This makes it difficult to cause decomposition by sodium hydroxide.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to embodiments.

(Example 1) The chemical structure is represented by the formula (2), Rf is a perfluorooxyalkylene chain, and -Y-
There -CH ₂ -, - Z is describing synthesis of -CH _3, n is 0, m is 2 of the fluorine-containing compound (Compound 1).

[0033]

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Ausimont Fomblin Z-DOL
(Average molecular weight 4000) (20 parts by weight)
Dissolve in E-7100 (200 parts by weight). To this 2-
Chloroethyl ether (4 parts by weight) was converted to methylene chloride (5 parts).
(0 parts by weight), refluxed for 12 hours, and then cooled to room temperature. After evaporating the reaction solution with an evaporator, 3M FC-72 (200 parts by weight), methylene chloride (50 parts by weight), and water (50 parts by weight) were added to the residue, and the mixture was stirred vigorously and allowed to stand for 48 hours. Divide into layers. Take the lower FC-72 layer and filter it with filter paper.
By evaporating 72 with an evaporator, the target compound 1 (20 parts by weight) is obtained.

In ¹⁹ F-NMR measurement, Fomblin Z
In -DOL, the positions of signals derived from CF ₂ next to the hydroxyl group were -83 ppm and -85 ppm. On the other hand, in the case of compound 1, the above signal was-
It shifted to 79 ppm and -81 ppm, respectively.

In IR measurement, Fomblin Z-DOL
Although absorption of a hydroxyl group was observed near 3600 to 3100 Kaiser, the absorption of the hydroxyl group in Compound 1 was reduced by the introduction of an oxyethylene moiety,
Near the 00 Kaiser, a new absorption due to the CH stretching of the terminal methyl group appeared.

(Example 2) The chemical structure is represented by the formula (2),
Rf is a perfluorooxyalkyl chain, -Y- is -C
A method for synthesizing a fluorine-containing compound (compound 2) in which H ₂ -and -Z are-(CH ₂ ) ₃ CH ₃ , n is 1 and m is 1 is described.

[0038]

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First, a method for synthesizing a compound in which the hydroxyl group of diethylene glycol mono-n-butyl ether is chlorinated (compound 2 ') will be described.

Diethylene glycol mono-n-butyl ether (6 parts by weight) is dissolved in a mixed solution of toluene (50 parts by weight) and pyridine (50 parts by weight), and the solution is heated to 80 ° C. with stirring. Add thionyl chloride (1
0 parts by weight) is added dropwise over 2 hours. Thereafter, heating and stirring are continued for 3 hours. After cooling the reaction solution to room temperature, it is poured into finely crushed ice (1000 parts by weight). After acidification with 5 wt% hydrochloric acid, extraction with toluene is performed. After the extract is dried over sodium sulfate, toluene is evaporated by an evaporator. Thus, a compound (compound 2 ') (6 parts by weight) in which the hydroxyl group of diethylene glycol mono-n-butyl ether is chlorinated is obtained.

Next, Demnum SA (average molecular weight: 3500) (35 parts by weight) manufactured by Daikin Industries, Ltd. was added to HFE-710 manufactured by 3M.
0 (200 parts by weight). A solution prepared by dissolving the total amount of the compound 2 '(6 parts by weight) obtained in the above method in methylene chloride (50 parts by weight) is added thereto, and the mixture is refluxed for 12 hours and then cooled to room temperature. After evaporating the reaction solution with an evaporator, 3M FC-72 (200 parts by weight), methylene chloride (50 parts by weight), and water (50 parts by weight) were added to the residue, and the mixture was stirred vigorously and allowed to stand for 48 hours. Divide into layers. The lower FC-72 layer is taken, filtered through filter paper, and then FC-72 is volatilized by an evaporator to obtain the desired compound 2 (35 parts by weight).

In the ¹⁹ F-NMR measurement, the position of the signal derived from CF ₂ next to the hydroxyl group was −128.
It was 5 ppm. On the other hand, the signal of compound 2 was shifted to -125 ppm by the introduction of the oxyethylene moiety.

In IR measurement, Fomblin Z-DOL
Although the absorption of a hydroxyl group was observed near 3600 to 3100 Kaiser, the absorption of the hydroxyl group in Compound 2 was reduced by the introduction of an oxyethylene moiety,
Near the 00 Kaiser, a new absorption due to the CH stretching of the terminal butyl group appeared.

Example 3 The chemical structure is represented by the formula (2):
Rf is a perfluorooxyalkyl chain, -Y- is -C
O -, - Z is _{- (CH 2) 11 CH 3} , n is describes a method for the synthesis of 2, m is 1 of the fluorine-containing compound (Compound 3).

First, a method for synthesizing a compound having a perfluorooxyalkyl chain having a COCl terminal (compound 3 ') will be described.

[0046]

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Dupont Krytox 157FSL
(Average molecular weight 2400) (25 parts by weight) is dissolved in Vertrel XF (100 parts by weight) manufactured by DuPont. Thionyl chloride (4 parts by weight) is added thereto, and the mixture is refluxed for 8 hours. After the reaction solution was cooled to room temperature, Vertrel XF was evaporated with an evaporator.
And thionyl chloride are volatilized to obtain compound 3 '(25 parts by weight).

Next, the entire amount (25 parts by weight) of the compound 3 'obtained by the above method was added to 3M HFE-7100 (200 parts by weight).
Parts by weight). A solution prepared by dissolving triethylene glycol mono-n-dodecyl ether (12 parts by weight) in methylene chloride (50 parts by weight) is added thereto, and after refluxing for 12 hours, the mixture is cooled to room temperature. After evaporating the reaction solution with an evaporator, the residue was FC-72 (200 parts by weight) manufactured by 3M.
And methylene chloride (50 parts by weight).
When left for a while, it separates into two layers. The lower FC-72 layer is taken, filtered through filter paper, and then FC-72 is evaporated by an evaporator to obtain the desired compound 3 (25 parts by weight).

In ¹⁹ F-NMR measurement, the position of the signal derived from CF adjacent to the carboxyl group was −134 ppm in Krytox 157 FSL. On the other hand, in the case of compound 3, the above signal was shifted to a low magnetic field of about 0.3 ppm due to the introduction of the oxyethylene moiety.

In the IR measurement, Krytox 157F
In SL, absorption due to CO stretching of the carboxyl group having a maximum value near 1780 Kaiser was observed, but compound 3 is converted to an ester bond by the introduction of the oxyethylene site, so that the compound 3 is derived from CO stretching. The absorption maximum shifted to around 1805 Kaiser. 3
OH of carboxyl group around 600-3100 Kaiser
Although absorption due to stretching was observed, the absorption of compound 3 was reduced by the introduction of the oxyethylene moiety,
A new absorption due to the CH stretching of the terminal dodecyl group appeared around 3000-2800 Kaiser.

Example 4 The chemical structure is represented by the formula (2), Rf is a perfluorooxyalkylene chain, and -Y-
There -CH ₂ -, - Z is _{- (CH 2) 11 CH 3} , n is 2, m is described a method for the synthesis of fluorine-containing compound 2 (Compound 4).

[0052]

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First, tetraethylene glycol mono-n
A method for synthesizing a compound in which the hydroxyl group of dodecyl ether is chlorinated (compound 4 ′) will be described.

Compound 4 'is diethylene glycol mono-
Obtained in the same manner as for compound 2 ', except that tetraethylene glycol mono-n-dodecyl ether (14 parts by weight) is used instead of n-butyl ether (6 parts by weight). The yield is 14 parts by weight.

Compound 4 is 2-chloroethyl ether (4
Parts by weight) instead of the total amount (14 parts by weight) of the compound 4 'obtained in the above reaction. The yield is 20 parts by weight.

In ¹⁹ F-NMR measurement, Fomblin Z
In -DOL, the positions of signals derived from CF ₂ next to the hydroxyl group were -83 ppm and -85 ppm. On the other hand, in the case of compound 4, the signal was shifted to -79 ppm and -81 ppm, respectively, due to the introduction of the oxyethylene moiety as in the case of compound 1.

In IR measurement, Fomblin Z-DO
As for L, the absorption of a hydroxyl group was observed around 3600 to 3100 Kaiser, but the absorption of the hydroxyl group was reduced in Compound 4 as in Compound 1 by the introduction of an oxyethylene site, and a new terminal was found near 3000 to 2800 Kaiser. Absorption from the CH stretching of the dodecyl group appeared.

(Example 5) The chemical structure is represented by the formula (2), Rf is a perfluorooxyalkylene chain, and -Y-
There -CH ₂ -, - Z is _{- (CH 2) 15 CH 3} , n is 7, m is described a method for the synthesis of fluorine-containing compound 2 (Compound 5).

[0059]

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First, octaethylene glycol mono-n
-A method for synthesizing hexadecyl ether (compound 5 ') is described.

Hexaethylene glycol (30 parts by weight)
Potassium hydroxide (12 parts by weight) is added to the mixture, and the mixture is vigorously stirred while heating to 100 ° C. When potassium hydroxide is dissolved, 2-bromoethanol (20 parts by weight) is added dropwise over 1 hour. After the addition, the mixture is stirred for 3 hours while heating to 100 ° C. Next, 2-bromoethanol in the reaction solution is volatilized by an evaporator. When evaporating 2-bromoethanol, it is preferable to use a vacuum pump instead of an aspirator to reduce the pressure. When an aspirator is used, usually only a reduced pressure of 20 to 30 mmHg can be obtained.
The 2-bromoethanol does not volatilize unless heated above ℃, but if a vacuum pump is used, the pressure can be reduced to 5 mmHg or less, so that it can be almost volatilized below 100 ℃. After volatilizing 2-bromoethanol, the reaction solution is dissolved in water (300 parts by weight). Organic matter is extracted from this with methylene chloride (100 parts by weight). After drying methylene chloride with sodium sulfate, it is volatilized by an evaporator to obtain octaethylene glycol (37 parts by weight).

Next, the whole amount (37 parts by weight) of octaethylene glycol obtained by the above operation is dissolved in tetrahydrofuran (THF) (500 parts by weight), and sodium hydride (3 parts by weight) is added thereto and stirred for 10 minutes. . While stirring, 1-bromohexadecane (35 parts by weight) was added to TH.
What was dissolved in F (200 parts by weight) was added dropwise over 2 hours. Thereafter, stirring is continued for 3 hours. Pour the reaction onto crushed ice (2000 parts by weight). After acidification with 5 wt% hydrochloric acid, extraction with methylene chloride is performed. After drying the extract over sodium sulfate, the methylene chloride is volatilized by an evaporator. Purification by silica gel column chromatography (developing solvent: ethyl acetate) gives a compound (compound 5 ') (36 parts by weight) in which one of the hydroxyl groups of octaethylene glycol has been substituted with a hexadecyloxy group.

Next, a method for synthesizing the compound (compound 5 ″) in which the hydroxyl group of the compound 5 ′ is chlorinated will be described, except that diethylene glycol mono-n-butyl ether (6 parts by weight) was used in place of diethylene glycol mono-n-butyl ether (6 parts by weight). Compound (5 ″) (36 parts by weight) in which the hydroxyl group of compound 5 ′ is chlorinated is obtained in the same manner as in the method for synthesizing compound 2 ′ in Example 2, except that the total amount of compound (′) is used (36 parts by weight).

Next, a method for synthesizing Compound 5 will be described. Compound 5 is obtained in the same manner as compound 1 except that compound 5 ″ (25 parts by weight) obtained in the above reaction is used instead of 2-chloroethyl ether (4 parts by weight). The yield is 21 parts by weight. .

In ¹⁹ F-NMR measurement, Fomblin Z
In -DOL, the positions of signals derived from CF ₂ next to the hydroxyl group were -83 ppm and -85 ppm. On the other hand, in the case of compound 5, the signal was shifted to -79 ppm and -81 ppm, respectively, due to the introduction of the oxyethylene moiety as in the case of compound 1.

In IR measurement, Fomblin Z-DOL
Although the absorption of a hydroxyl group was observed near 3600 to 3100 Kaiser, the absorption of a hydroxyl group in Compound 5 was reduced by the introduction of an oxyethylene moiety as in Compound 1,
A new absorption due to CH stretching of the terminal hexadecyl group appeared around 3000 to 2800 Kaiser.

(Example 6) The chemical structure is represented by the formula (2),
Rf is a perfluorooxyalkyl chain, -Y- is -C
A method for synthesizing a fluorine-containing compound (compound 6) in which ONHCH ₂ CH ₂ — and -Z are — (CH ₂ ) ₁₁ CH ₃ , n is 4 and m is 1 is described.

[0068]

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First, tetraethylene glycol mono-n
- The synthesis of compounds in which a hydroxyl group has been substituted with TsNCH ₂ CH ₂ O groups dodecyl ether (Compound 6 '). The Ts group is a paratoluenesulfonyl group.

Ethanolamine (4 parts by weight) is dissolved in pyridine (50 parts by weight). To this solution is added paratoluenesulfonyl chloride (28 parts by weight), and the mixture is stirred at room temperature for 2 hours and subsequently at 60 ° C. for 3 hours. After the reaction solution is cooled to room temperature, it is poured into 10 wt% hydrochloric acid (300 parts by weight). After the precipitated solid is washed with 1 wt% hydrochloric acid, it is washed with water until the washing liquid becomes neutral. The crystals were recrystallized from 1-propanol.
The compound (20 parts by weight) introduced therein is obtained. Next, tetraethylene glycol mono-n-dodecyl ether (14 parts by weight) is dissolved in THF (100 parts by weight), and sodium hydride (1 part by weight) is added thereto and stirred. A solution obtained by dissolving the total amount (20 parts by weight) of the compound obtained by introducing two Ts groups into ethanolamine synthesized by the above method in THF (100 parts by weight) is added dropwise over 2 hours. After the addition, the mixture is stirred for 3 hours. The reaction solution is poured on finely crushed ice (500 parts by weight). After acidification with 5 wt% hydrochloric acid, extraction with methylene chloride is performed. After drying the extract over sodium sulfate, the methylene chloride is volatilized by an evaporator. Silica gel column chromatography (developing solvent ethyl acetate) to give a compound in which a hydroxyl group in purified with tetraethylene glycol mono -n- dodecyl ether is substituted with TsNCH ₂ CH ₂ O groups (Compound 6 ') (17 parts by weight).

Next, a method for synthesizing the compound (compound 6 ″) in which the Ts group of the compound 6 ′ has been replaced with hydrogen will be described.The total amount (17 parts by weight) of the compound 6 ′ synthesized by the above method is converted into THF (1 part).
00 parts by weight), lithium aluminum hydride (5 parts by weight) is added thereto, and the mixture is refluxed for 48 hours. After cooling the reaction solution to room temperature, it is poured into finely crushed ice (1000 parts by weight). After acidification with 5 wt% hydrochloric acid, extraction with methylene chloride is performed. After drying the extract over sodium sulfate, the methylene chloride is volatilized by an evaporator. Compound (compound 6 ″) that was purified by silica gel column chromatography (developing solvent: ethyl acetate) and the Ts group of compound 6 ′ was replaced with hydrogen.
(8 parts by weight).

Next, a method for synthesizing Compound 6 will be described. Demnum SH (average molecular weight 3500) (35 parts by weight) manufactured by Daikin Industries, Ltd. was converted to Vertrel XF (100 parts by weight) manufactured by DuPont.
Dissolve in To this was added thionyl chloride (4 parts by weight),
Reflux for 8 hours. After the reaction solution was cooled to room temperature, vertrel XF and thionyl chloride were volatilized by an evaporator to obtain a compound (35 parts by weight) in which CO ₂ H at the terminal of Demnum SH was converted to COCl. The total amount (35 parts by weight) is 3M
It is dissolved in HFE-7100 (200 parts by weight) manufactured by the company. A solution prepared by dissolving the entire amount (8 parts by weight) of the compound 6 ″ obtained by the above method in a mixed solvent of methylene chloride (50 parts by weight) and pyridine (2 parts by weight) was added, and the mixture was refluxed for 12 hours and then cooled to room temperature. After evaporating the reaction solution with an evaporator, 3M FC-72 (200 parts by weight), methylene chloride (100 parts by weight), and 5 wt% hydrochloric acid (100 parts by weight) were added to the residue, and the mixture was stirred vigorously. After standing for 48 hours, the mixture is divided into three layers, the lower FC-72 layer is taken, filtered through filter paper, and then the FC-72 is volatilized by an evaporator to obtain the desired compound 6 (35 parts by weight).

In the ¹⁹ F-NMR measurement, the position of the signal derived from CF ₂ next to the carboxyl group was −
It was 124 ppm. On the other hand, Compound 6 had an oxyethylene moiety introduced, but the signal was -124 ppm.

In IR measurement, Demnum SH was 1780
Although absorption due to CO stretching of the carboxyl group having a local maximum value near Kaiser was observed, Compound 6 has a maximum value of absorption derived from CO stretching due to the change to an amide bond with the introduction of an oxyethylene moiety. It shifted to around 1710 Kaiser. In addition, a maximum value of the absorption derived from NH bending of the amide bond newly appeared around 1540 Kaiser.

(Example 7) The chemical structure is represented by the formula (3), Rf is a perfluorooxyalkyl chain, and -Z is-
A method for synthesizing (CH ₂ ) ₃ CH ₃ , wherein n is 1 and m is 1 is described.

[0076]

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First, when the hydroxyl group of diethanolamine is O
(CH ₂ ) ₂ O (CH ₂ ) ₃ CH ₃ group, NH is replaced with NTs
The method for synthesizing the compound (Compound 7 ′) converted to is shown below.
The Ts group is a paratoluenesulfonyl group.

Diethanolamine (6 parts by weight) is dissolved in pyridine (100 parts by weight). To this solution is added paratoluenesulfonyl chloride (35 parts by weight), and the mixture is stirred at room temperature for 2 hours and then at 60 ° C. for 3 hours. After the reaction solution is cooled to room temperature, it is poured into 10 wt% hydrochloric acid (1000 parts by weight). After the precipitated solid is washed with 1 wt% hydrochloric acid, it is washed with water until the washing liquid becomes neutral. Recrystallization from 1-propanol gives a compound (23 parts by weight) in which three paratoluenesulfonyl groups (Ts groups) have been introduced into diethanolamine.

[0079]

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Next, ethylene glycol mono-n-butyl ether (20 parts by weight) is dissolved in THF (100 parts by weight), and sodium hydride (2 parts by weight) is added thereto and stirred. The diethanolamine synthesized by the above method was added to T
The total amount (23 parts by weight) of the compound into which three s groups were introduced was TH
What was dissolved in F (100 parts by weight) was added dropwise over 2 hours. After the addition, the mixture is stirred for 3 hours. The reaction solution is poured on finely crushed ice (500 parts by weight). After acidification with 5 wt% hydrochloric acid, extraction with methylene chloride is performed. After drying the extract over sodium sulfate, the methylene chloride is volatilized by an evaporator. Purification by silica gel column chromatography (developing solvent is ethyl acetate), the hydroxyl group of diethanolamine was replaced by O (CH ₂ ) ₂ O (CH ₂ ) ₃ CH ₃ group, and NH was changed to N
A compound (compound 7 ') (14 parts by weight) converted to Ts is obtained.

Next, a method for synthesizing a compound (Compound 7 ″) in which the Ts group of Compound 7 ′ has been replaced with hydrogen will be described.
00 parts by weight), lithium aluminum hydride (5 parts by weight) is added thereto, and the mixture is refluxed for 48 hours. After cooling the reaction solution to room temperature, it is poured into finely crushed ice (1000 parts by weight). After acidification with 5 wt% hydrochloric acid, extraction with methylene chloride is performed. After drying the extract over sodium sulfate, the methylene chloride is volatilized by an evaporator. Compound (compound 7 ″) (6) obtained by purifying by silica gel column chromatography (developing solvent: ethyl acetate) and substituting the Ts group of compound 7 ′ with hydrogen.
Parts by weight).

[0082]

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Next, a method for synthesizing Compound 7 will be described. Dekinnum SH (average molecular weight: 3500) (35 parts by weight) manufactured by Daikin Industries, Ltd. is dissolved in Vertrel XF (100 parts by weight) manufactured by DuPont. To this was added thionyl chloride (4 parts by weight), and 8
Reflux for hours. After the reaction solution was cooled to room temperature, Vertrel XF and thionyl chloride were volatilized with an evaporator to convert the terminal CO ₂ H of Demnum SH into COCl (3).
5 parts by weight). The entire amount (35 parts by weight) is dissolved in 3M HFE-7100 (200 parts by weight). A solution prepared by dissolving the total amount (6 parts by weight) of the compound 7 ″ obtained by the above method in a mixed solvent of methylene chloride (50 parts by weight) and pyridine (2 parts by weight) was added, and the mixture was refluxed for 12 hours and then cooled to room temperature. After evaporating the reaction solution with an evaporator, the residue was FC-72 (200 parts by weight), methylene chloride (100 parts by weight), and 5 wt% hydrochloric acid (100 parts by weight).
(Parts by weight) and vigorously stirred, and then allowed to stand for 48 hours to separate into three layers. The lower FC-72 layer is taken, filtered through filter paper, and then FC-72 is evaporated by an evaporator to obtain the desired compound 7 (35 parts by weight).

In the ¹⁹ F-NMR measurement, the position of the signal derived from CF ₂ adjacent to the carboxyl group was −
It was 124 ppm. On the other hand, Compound 7 had an oxyethylene moiety introduced, but the signal was -124 ppm.

In IR measurement, Demnum SH was 1780
Although absorption due to CO stretching of the carboxyl group having a maximum value near Kaiser was observed, compound 7 has a maximum value of absorption derived from CO stretching due to the change of this portion to an amide bond with the introduction of an oxyethylene moiety. It shifted to around 1700 Kaiser. Further, the absorption derived from NH bending angle observed in Compound 6 was not observed in Compound 7.

(Example 8) The thermal stability of the fluorine-containing compound of the present invention was examined. For comparison, compounds having a perfluorooxyalkylene chain or a crown ether structure at the end of the perfluorooxyalkyl chain (compounds 8, 9 respectively)
Was also used. The evaluation method was as follows.
After being placed in a sample tube, it was immersed in a 150 ° C. oil bath for 30 hours, and then checked for any change in structure. As a result, ¹ H-NMR of Compounds 1 to 7 showed no particular change, but those of Compounds 8 and 9 showed that the signal derived from the oxyethylene chain of 3.5 to 3.9 ppm was 3.3 to 5.0 ppm. It spread to around. At 8 ppm, a signal derived from -OCHO generated by (oxidative) decomposition of the crown ether ring appeared.

Compound 8 was compound 5 '(36 parts by weight)
Instead of 2-hydroxymethyl 15-crown-5
(Yield: 20 parts by weight) except that (15 parts by weight) was used. Compound 9 was synthesized in the same manner as compound 6 except that 2-amino 15-crown-5 (4 parts by weight) was used instead of compound 6 ″ (8 parts by weight) (yield: 20 parts by weight).

Example 9 The effect of the fluorine-containing compound of the present invention as a surface modifier was examined. A 2.5 inch silicon wafer was prepared using 0.1% by weight of compound 1 to 7 of FC-72.
After being immersed in the solution for 1 minute and pulled up at a pulling rate of 1 mm / s, the solvent was volatilized by being left at room temperature for 2 hours to form a film of compounds 1 to 7 of the present invention on the wafer surface.

Next, the results of examining the contact angles of these wafer surfaces with water are shown in Table 1. The contact angle on the wafer surface where no compound film was formed was 26 °.

[0090]

[Table 1]

From the results, it was found that the compound of the present invention was effective as a surface modifier for improving water repellency.

Example 10 The scattering properties of the fluorine-containing compound of the present invention were examined. The silicon wafer on which the films of compounds 1 to 7 formed in Example 9 were formed was placed in a thermostat at 120 ° C. for 10 minutes.
The remaining amount of the compound on the wafer after standing for a time was estimated by IR (a change in absorption intensity of each compound due to CF stretching vibration). Table 2 shows the results.

[0093]

[Table 2]

The ratio of the remaining amount is a value obtained by dividing the absorption maximum near 1240 Kaiser after being left in a thermostat at 120 ° C. for 10 hours by the absorption maximum before being put into the thermostat. The larger this value is, the lower the scattering property is. As a comparative example of Compounds 1 to 7, Fomblin AM2001 (a fluorinated compound manufactured by Ausimont Co., Ltd., having an average molecular weight of about 2000 and indicated as Compound 10 in Table 2) was also evaluated.

From the results, it was found that the compounds of the present invention had low scattering properties.

(Example 11) A Ni-P layer and a Cr layer were provided on the surface of a 5.25 inch Al alloy disk, and a Ni-Co magnetic layer was sputter-deposited thereon to a thickness of 50 nm. Then, a disk having a protective layer made of carbon and having a thickness of 50 nm is prepared. This disc was immersed in a 0.1 wt% FC-72 solution of Compounds 1 to 7 for 1 minute, then pulled up at a pulling rate of 1 mm / s, left at room temperature for 2 hours to volatilize the solvent, A disc having a film formed on the surface was prepared. FIG. 1 shows the configuration. The sliding characteristics of these disks were measured using the CSS method (contact start / stop method: Onoda Cement Co., Ltd.)
Manufactured). The conditions were: rotation speed: 3600 rpm, 1 cycle: 30 seconds, final cycle number: 1000 cycles, head load: 10 g, and evaluated by frictional force at the time of stiction in the final cycle. As a comparative example, ammonium stearate (hereinafter referred to as compound 11) was also evaluated.
Table 3 shows the results.

[0097]

[Table 3]

From the results, it was found that the sliding characteristics of the surface of the magnetic recording medium of the present invention were very high. From this, it was found that the use of the fluorine-containing compound of the present invention improved the surface sliding characteristics.

[0099]

As described above, it has become possible to provide a fluorine-containing compound having low scattering property and high thermal stability, and a magnetic recording medium using the same.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration of a magnetic recording medium used in Example 11.

[Explanation of symbols]

1 ... Al alloy disk, 2 ... Ni-P layer, 3 ... Cr layer,
4 magnetic layer, 5 protective layer, 6 layer containing the compound of the present invention.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C10M 107/38 C10M 107/38 G11B 5/62 G11B 5/62 5/71 5/71 5/72 5/72 // C10N 40 : 14 (72) Inventor Mina Ishida 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Yutaka Ito 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture (72) Inventor Hiroyuki Matsumoto 2880 Kozu, Odawara-shi, Kanagawa Prefecture Storage Systems Division, Hitachi, Ltd.

Claims (5)

[Claims] (1) The following general formula (1): (Wherein -X is a group containing an acyclic oxyethylene chain, and -X does not contain an amino group. M is 1 or 2. Rf is a perfluoropolyoxyalkyl chain having an average molecular weight of 800 or more, or A fluorine-containing compound having an oxyethylene moiety represented by a perfluoropolyoxyalkylene chain. 2. The following general formula (2): -Z represents a linear or branched alkyl group having 1 to 16 carbon atoms, or COR (R represents a linear or branched alkyl group). n is an integer from 0 to 7. m is 1 or 2. Rf is a perfluoropolyoxyalkyl chain or a perfluoropolyoxyalkylene chain having an average molecular weight of 800 or more. A) a fluorine-containing compound having an oxyethylene moiety; 3. The following general formula (3): (In the formula, -Z is a linear or branched alkyl group having 1 to 16 carbon atoms, or COR (R represents a linear or branched alkyl group.), N is an integer of 0 to 7, and m is 1 or 2. R
f is a perfluoropolyoxyalkyl chain or a perfluoropolyoxyalkylene chain having an average molecular weight of 800 or more. A) a fluorine-containing compound having an oxyethylene moiety; 4. A magnetic recording medium comprising at least one magnetic layer on a nonmagnetic support, wherein the magnetic layer or a protective layer provided outside the magnetic layer is provided on the surface of the magnetic layer. A magnetic recording medium comprising a film containing the fluorine-containing compound according to claim 2 or 3 as an outermost layer. 5. A non-magnetic support comprising a soda lime glass containing sodium ions or potassium ions, wherein the sum of the contents of the sodium ions and the potassium ions is at least 5 wt%. Magnetic recording medium.