JP2016222580A - Glycoluril compound having fluoropolyether group, lubricant and magnetic disc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a test compound used for a lubricant forming a lubricating film on a protective layer such as a carbon protective film for abrasion suppression or surface protection from contact and sliding with a magnetic head on a surface of a magnetic disc.SOLUTION: There is provided a glycoluril compound having a fluoropolyether group obtained by reacting a glycoluril compound having a glycidyl group represented by the formula (II) and a fluoropolyether group represented by the formula (III).SELECTED DRAWING: None

Description

  The present invention relates to a glycoluril compound having a fluoropolyether group, a lubricant, and a magnetic disk.

In recent years, the distance between a magnetic disk as a recording medium and a magnetic head for recording / reproducing information (space between the head and the disk) has become shorter as the recording density of the magnetic disk increases. Therefore, the contact frequency between the magnetic head and the magnetic disk is increasing.
The surface of this magnetic disk has a protective layer such as a carbon protective film, followed by a lubricating layer containing a lubricant for preventing wear due to contact / sliding with the magnetic head and preventing contamination of the surface. Is formed.

As the lubricant, a fluoropolyether compound is generally used, and examples thereof include a trade name “Fomblin Ztetraol” (manufactured by Solvay Solexis) and a trade name “PHOSFAROL A-20H” (manufactured by MORESCO). be able to. These lubricants are strongly adsorbed to the surface of the magnetic disk because they contain a fluoropolyether compound in which hydroxy groups having high polarity are bonded to both ends of the molecule. As a result, the lubricant film (lubricating layer) is not scattered even when the magnetic disk rotates at a high speed, and is retained for a long period of time.
Patent Document 1 discloses a lubricant comprising a fluoropolyether compound having a hydroxy group in the molecular chain in addition to both molecular ends. In this lubricant, the hydroxy groups in the molecular chain are strongly adsorbed to the surface of the magnetic disk together with the hydroxy groups at both ends of the molecule. The film thickness can be reduced. As a result, the gap between the head / disk can be narrowed.

However, since such a fluoropolyether compound is poor in stability to a Lewis acid such as Al ₂ O ₃ in the head member, it undergoes a decomposition reaction by contact with the head (see, for example, Non-Patent Document 1). ). As a result, there is a problem that the lubricant film volatilizes and disappears from the magnetic disk, and the film cannot be retained.

JP 2006-70173 A

Macromolecules, 1992, 25, p6791- 6799.

  The present invention has been made in view of such circumstances, and includes a glycoluril compound having a fluoropolyether group, a lubricant containing the compound as a component, and a magnetic layer formed with a lubricant layer containing the lubricant. The purpose is to provide a disc.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that a glycoluril compound having a fluoropolyether group and a hydroxy group is suitable as a component of a lubricant. It has come to completion.

  That is, the first invention is a glycoluril compound represented by the chemical formula (I) having a fluoropolyether group.

  A second invention is a lubricant comprising the glycoluril compound of the first invention as a component.

  A third invention is a magnetic disk characterized in that a recording layer and a protective layer are formed in this order on a support, and a lubricating layer containing the lubricant of the second invention is formed on the surface of the protective layer. is there.

  The lubricant containing the glycoluril compound of the present invention as a component is stable against Lewis acid and the like because the thickness of the lubricant film (lubricating layer) can be reduced and the chemical resistance is excellent. The magnetic disk on which the lubricating layer containing the lubricant of the present invention is formed can narrow the gap between the head and the disk when the magnetic disk is used in the magnetic disk device, and the head and the disk are in contact with and slid. Even so, the lubricant film can be retained.

Hereinafter, the present invention will be described in detail.
The glycoluril compound of the present invention represented by the chemical formula (I) is, for example, a linear fluoropolyether having a hydroxy group at one end and an ester group, a silyl group or an alkoxy group at the other end (hereinafter, A “precursor fluoropolyether compound”) and a glycoluril compound having a glycidyl group represented by the chemical formula (II) (hereinafter also referred to as “precursor glycoluril compound”). It is obtained by reacting.

（式中、Ｒ^１およびＲ^２は、同一または異なって、水素原子、低級アルキル基またはフェニル基を表す。Ｒ^７、Ｒ^８およびＲ^９は、同一または異なって、アリル基またはグリシジル基を表す。）

(Wherein R ¹ and R ² are the same or different and represent a hydrogen atom, a lower alkyl group or a phenyl group. R ⁷ , R ⁸ and R ⁹ are the same or different and represent an allyl group or a glycidyl group. .)

The precursor fluoropolyether compound will be described.
This fluoropolyether compound reacts with a linear fluoropolyether having a hydroxy group at both ends (hereinafter sometimes referred to as “compound (1)”) and a hydroxy group to produce an ester group, a silyl group or an alkoxy group. It is obtained by reacting with a compound that forms or imparts (hereinafter sometimes referred to as “compound (2)”).
In this reaction, the reaction temperature is preferably 10 to 60 ° C, more preferably 20 to 40 ° C. The reaction time is preferably 2 to 20 hours, and more preferably 10 to 15 hours. It is preferable that the usage-amount of a compound (2) is 0.5-1.5 equivalent with respect to a compound (1).
This reaction may be carried out in a solvent, or a reaction accelerator may be used. Examples of the solvent include 1,4-dioxane, dimethylformaldehyde, dimethyl sulfoxide, dimethylacetamide and the like. Examples of the reaction accelerator include pyridine, imidazole, sodium hydride and the like.
After completion of the reaction, the precursor fluoropolyether compound can be obtained, for example, by purification by column chromatography.

  Examples of the compound (1) include a compound represented by the chemical formula (III).

（式中、ｍは、０〜２０の整数を表すが、０〜１０であることが好ましく、０〜４であることがより好ましく、１〜３であることが更に好ましく、１〜２であることが特に好ましい。）

(In the formula, m represents an integer of 0 to 20, preferably 0 to 10, more preferably 0 to 4, still more preferably 1 to 3, and more preferably 1 to 2. Is particularly preferred.)

The number average molecular weight of the compound represented by the chemical formula (III) is preferably 300 to 2000, more preferably 400 to 1200, and still more preferably 500 to 800.
The number average molecular weight can be determined by ¹⁹ F-NMR.

Examples of the compound (2) include acid anhydrides, silyl halides, and alkyl halides.
As the acid anhydride, succinic anhydride, maleic anhydride, phthalic anhydride or the chemical formula R ^a OR ^b (wherein R ^a and R ^b are the same or different and are represented by CH ₃ CO, PhCO, CF ₃ CH ₂ CO, A compound represented by CH ₃ SO ₂ , PhSO ₂ , CH ₃ C ₆ H ₄ SO ₂ or CF ₃ SO ₂ ).
Examples of the compound represented by the chemical formula R ^a OR ^b include acetic anhydride, benzoic anhydride, acetic benzoic anhydride, trifluoromethylacetic anhydride, methanesulfonic anhydride, benzenesulfonic anhydride, p-toluenesulfonic anhydride And trifluoromethanesulfonic anhydride.

As a silyl halide, formula ^(R _c) ^{3 SiX,} in _^R d ^(R _e) 2 SiX or ^R d ^R e ^R f SiX (wherein, ^{R c} represents an alkyl group or a phenyl group having 1 to 4 carbon atoms. R ^d represents an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, a benzyl group, pentafluorophenyl group, .R represents a cyanopropyl group or a vinyl group ^e is 1 to carbon atoms 2 represents an alkyl group or a phenyl group, and R ^f represents a C1-C4 alkyl group having a phenyl group, and X represents a halogen atom such as chlorine, bromine, iodine, etc.). Can be mentioned.
Examples of such silyl halides include trimethylsilyl chloride, triethylsilyl chloride, triisopropylsilyl chloride, t-butyldimethylsilyl chloride, t-butyldiphenylsilyl chloride, t-butoxydiphenylchlorosilane, (3-cyanopropyl) dimethylchlorosilane, Benzylchlorodimethylsilane, butyldimethylchlorosilane, chloro (decyl) dimethylsilane, chloro (dodecyl) dimethylsilane, chlorodimethyl (3-phenylpropyl) silane, chlorodimethylphenylsilane, chlorodimethylpropylsilane, chlorodimethylvinylsilane, diethylisopropylsilyl Chloride, dimethyl-n-octylchlorosilane, dimethylethylsilyl chloride, dimethylisopropylchlorosilane Dimethyl octadecyl chlorosilane, diphenylmethylchlorosilane, methyl octadecyl (3-phenylpropyl) chlorosilane, pentafluorophenyl dimethylchlorosilane, triphenyl chlorosilane, and the like.

Examples of the alkyl halide include compounds represented by the chemical formula R ^g X (wherein R ^g represents an alkyl group having 1 to 5 carbon atoms, X represents a halogen atom such as chlorine, bromine, iodine, etc.). it can.
Examples of such alkyl halides include chloromethane, bromomethane, iodomethane, chloroethane, bromoethane, iodoethane, 1-bromopropane, 2-bromopropane, 1-iodopropane, 2-iodopropane, and 1-bromo-2-methylpropane. 2-bromo-2-methylpropane, 1-iodo-2-methylpropane, 2-iodo-2-methylpropane, 1-bromobutane, 2-bromobutane, 1-iodobutane, 2-iodobutane, 1-bromo-3- Examples thereof include methylbutane, 2-bromo-2-methylbutane, 1-iodo-2-methylbutane, 1-iodo-3-methylbutane, 1-bromopentane, and 3-bromopentane.

  Examples of the synthesis pattern of the precursor fluoropolyether compound are shown in Schemes (A) and (B). Note that scheme (A) is an example using acetic anhydride as the compound (2), and scheme (B) is an example using trimethylsilyl chloride as the compound.

（式中、ｍは、０〜２０の整数を表す。）

(In the formula, m represents an integer of 0 to 20.)

Next, the precursor glycoluril compound will be described.
Examples of the precursor glycoluril compound include:
1,3,4,6-tetraglycidylglycoluril,
1,3,4,6-tetraglycidyl-3a-methylglycoluril,
1,3,4,6-tetraglycidyl-3a, 6a-dimethylglycoluril,
1,3,4,6-tetraglycidyl-3a, 6a-diphenylglycoluril,
1-allyl-3,4,6-triglycidyl glycoluril,
1-allyl-3,4,6-triglycidyl-3a-methylglycoluril,
1-allyl-3,4,6-triglycidyl-3a, 6a-dimethylglycoluril,
1-allyl-3,4,6-triglycidyl-3a, 6a-diphenylglycoluril,
1,3-diallyl-4,6-diglycidylglycoluril,
1,3-diallyl-4,6-diglycidyl-3a-methylglycoluril,
1,3-diallyl-4,6-diglycidyl-3a, 6a-dimethylglycoluril,
1,3-diallyl-4,6-diglycidyl-3a, 6a-diphenylglycoluril,
1,4-diallyl-3,6-diglycidylglycoluril,
1,4-diallyl-3,6-diglycidyl-3a-methylglycoluril,
1,4-diallyl-3,6-diglycidyl-3a, 6a-dimethylglycoluril,
1,4-diallyl-3,6-diglycidyl-3a, 6a-diphenylglycoluril,
1,3,4-triallyl-6-glycidylglycoluril,
1,3,4-triallyl-6-glycidyl-3a-methylglycoluril,
Examples include 1,3,4-triallyl-6-glycidyl-3a, 6a-dimethylglycoluril, 1,3,4-triallyl-6-glycidyl-3a, 6a-diphenylglycoluril and the like.

Among the precursor glycoluril compounds, the glycoluril compounds in which R ⁷ , R ⁸ and R ^{9 in the} chemical formula (II) are glycidyl groups can be synthesized according to the method described in JP-A-2015-54856. it can. Other glycoluril compounds in which at least one selected from R ⁷ , R ⁸ and R ⁹ is an allyl group can be synthesized according to the method described in JP-A-10-316665. .

As described above, the glycoluril compound of the present invention is obtained by reacting a precursor fluoropolyether compound with a precursor glycoluril compound. This reaction is carried out in the presence of a catalyst or an alkali metal. Done.
Examples of the catalyst include alkali compounds such as t-butoxy sodium, t-butoxy potassium, and sodium hydride. Examples of the alkali metal include sodium and potassium.
In this reaction, the reaction temperature is preferably 0 to 100 ° C, more preferably 50 to 90 ° C. The reaction time is preferably 3 to 100 hours, and more preferably 6 to 24 hours.
The amount of the precursor glycoluril compound used is preferably 0.2 to 10.0 equivalents relative to the precursor fluoropolyether compound. The amount of the catalyst used is preferably 0.05 to 1.0 equivalent relative to the precursor fluoropolyether compound. The amount of alkali metal used is preferably 1.0 to 8.0 equivalents relative to the precursor fluoropolyether compound.
This reaction may be carried out in a solvent. Examples of the solvent include t-butyl alcohol, toluene, xylene and the like.

After completion of the reaction, for example, after washing with water and dehydrating, a protecting group such as an ester group, silyl group or alkoxy group bonded to the end of the fluoropolyether chain of the reaction product is deprotected by hydrolysis or the like. At that time, a deprotection accelerator such as tetrabutylammonium fluoride, potassium fluoride, sodium fluoride or the like may be used.
As a result, a glycoluril compound in which Y in the chemical formula (I) is —OH (note: chemical formula (a)) (hereinafter sometimes referred to as “glycoluril compound (Ia)”) can be obtained. This glycoluril compound (Ia) is included in the glycoluril compound of the present invention.

  In the chemical formula (I), the glycoluril compound in which Y is a group represented by the chemical formula (b), (c), (d) or (e), respectively, obtains the glycoluril compound (Ia) as a starting material. be able to.

（式中、ｎは、１〜６の整数を表すが、１〜４であることが好ましく、２〜４であることがより好ましい。）

(In formula, although n represents the integer of 1-6, it is preferable that it is 1-4, and it is more preferable that it is 2-4.)

  By reacting the glycoluril compound (Ia) with the haloalcohol represented by the chemical formula (IV) in the presence of an alkali metal, Y in the chemical formula (I) is a group represented by the chemical formula (b). A certain glycoluril compound (hereinafter sometimes referred to as “glycoluril compound (Ib)”) can be obtained.

（式中、Ｘは、塩素、臭素、ヨウ素などのハロゲン原子を表す。ｎは、１〜６の整数を表すが、１〜４であることが好ましく、２〜４であることがより好ましい。）

(In formula, X represents halogen atoms, such as chlorine, a bromine, and iodine. Although n represents the integer of 1-6, it is preferable that it is 1-4, and it is more preferable that it is 2-4. )

  By reacting the glycoluril compound (Ia) with glycidol in the presence of a catalyst, the glycoluril compound (hereinafter referred to as “glycol”) wherein Y in the chemical formula (I) is a group represented by the chemical formula (c). Uril compound (Ic) ”may be obtained.

  By reacting the glycoluril compound (Ia) with glycidyl phenyl ether in the presence of a catalyst, a glycoluril compound (hereinafter referred to as Y) in the chemical formula (I) is a group represented by the chemical formula (d). (Sometimes referred to as “glycoluril compound (Id)”).

Glycoluril compound (Ia) and glycidyl 4-methoxyphenyl ether are reacted in the presence of a catalyst, whereby Y in chemical formula (I) is a group represented by chemical formula (e). (Hereinafter sometimes referred to as “glycoluril compound (Ie)”).
These glycoluril compounds (Ib) to (Ie) are also included in the glycoluril compound of the present invention in the same manner as the glycoluril compound (Ia).

In these reactions for obtaining the glycoluril compounds (Ib) to (Ie), the reaction temperature is preferably 50 to 100 ° C, more preferably 70 to 90 ° C. The reaction time is preferably 20 to 100 hours, and more preferably 50 to 80 hours.
The amount of the haloalcohol, glycidol, glycidyl phenyl ether or glycidyl 4-methoxyphenyl ether represented by the chemical formula (IV) is 1.0 to 2.0 equivalents based on the hydroxy group of the glycoluril compound (Ia). Preferably there is. The amount of the alkali metal used is preferably 1.0 to 2.0 equivalents based on the hydroxy group of the glycoluril compound (Ia). The amount of the catalyst used is preferably 0.05 to 0.1 equivalent based on the hydroxy group of the glycoluril compound (Ia).
Examples of the alkali metal include sodium and potassium. Examples of the catalyst include alkali compounds such as t-butoxy sodium, t-butoxy potassium, and sodium hydride.
These reactions may be performed in a solvent. Examples of the solvent include t-butyl alcohol, toluene, xylene and the like.
After completion of the reaction, for example, after washing with water and dehydration, the desired glycoluril compound can be obtained by purification by column chromatography.

By using the glycoluril compound of the present invention as a component of a magnetic disk lubricant, the gap between the head and the disk in the magnetic disk apparatus can be narrowed, and even if the head and the disk contact and slide, the lubricant The film can be retained.
Moreover, the glycoluril compound of the present invention can form a weak chemical bond with a polar site present in the carbon protective film by a hydroxy group in the molecule. Therefore, in addition to magnetic disks, magnetic heads having a carbon protective film, magneto-optical recording members, magnetic tapes, components for forming a surface protective film of organic materials such as plastic, and further inorganic materials such as glass and metals It is also suitable as a component of the surface protective film forming agent.

The lubricant of the present invention may contain a solvent or other lubricant as a component other than the glycoluril compound of the present invention.
Examples of the solvent include, for example, trade name “PF-5060”, trade name “PF-5080”, trade name “HFE-7100”, trade name “HFE-7200” (manufactured by 3M), trade name “Vertrel XF”. (Manufactured by DuPont). When a solvent is used, the concentration of the glycoluril compound of the present invention is preferably 1% by weight or less, and more preferably 0.001 to 0.1% by weight.
As other lubricants, for example, trade name “Fomlin Zdol”, trade name “Fomlin Ztetraol”, trade name “Fomlin Zdol TX”, trade name “Fomlin AM” (above, Solvay Solexis), trade name “Demnum”. (Manufactured by Daikin Industries, Ltd.), trade name “Krytox” (manufactured by DuPont), and the like. These lubricants can be used in combination with the glycoluril of the present invention at an appropriate ratio.

  The magnetic disk of the present invention has at least one recording layer formed on a support and a protective layer formed thereon, and further has a lubricating layer containing the lubricant of the present invention as an outermost layer.

Examples of the material for the support include aluminum alloys, ceramics such as glass, and polycarbonate.
As the material of the recording layer (magnetic layer), an alloy containing, as a main component, an element capable of forming a ferromagnetic material such as iron, cobalt, nickel, etc., and added with chromium, platinum, tantalum, etc., or an oxide of these alloys Can be mentioned. The recording layer can be formed by a plating method or a sputtering method.
Examples of the material for the protective layer include carbon, SiC, SiO _{2 and the} like. The protective layer can be formed by sputtering or CVD.

  In a general magnetic disk, the thickness of the lubricant film is 30 mm or less. Therefore, if a lubricant having a viscosity of about 100 mPa · s or more at 20 ° C. is applied as it is, the thickness of the film may become too large. Therefore, when applying the lubricant, it is preferable to dilute with a solvent. When only the glycoluril compound of the present invention is used as a component of the lubricant of the present invention or when other lubricants are used in combination, the thickness of the film can be easily controlled by containing a solvent. In this case, the concentration of the glycoluril of the present invention is appropriately set depending on the coating method, conditions, ratio and the like. In the lubricant of the present invention, the thickness of the film is preferably 5 to 15 mm.

In order to promote adsorption of the lubricant to the protective layer, heat treatment or ultraviolet treatment can be performed after the lubricant layer is formed.
In the case of heat treatment, the treatment temperature is preferably 60 to 150 ° C, more preferably 80 to 150 ° C.
In the case of ultraviolet treatment, it is preferable to use ultraviolet rays having wavelengths of 185 nm and 254 nm as main wavelengths for irradiation.

The magnetic disk of the present invention can be used in a magnetic disk device. This magnetic disk device is composed of a magnetic disk, a head for recording / reproducing / erasing information, a disk drive including a motor for rotating the disk, and a control system for controlling the drive. The
As an application of the magnetic disk device including the magnetic disk of the present invention, an external memory such as an electronic computer or a word processor can be cited. Other applications include various devices such as navigation systems, games, mobile phones, PHS, crime prevention for buildings, and internal / external recording devices for management / control systems such as power plants.

Claims (3)

A glycoluril compound represented by the chemical formula (I) having a fluoropolyether group.

A lubricant comprising the glycoluril compound according to claim 1 as a component. A magnetic disk comprising: a recording layer and a protective layer formed in this order on a support; and a lubricating layer containing the lubricant according to claim 2 formed on the surface of the protective layer.