Fluoropolyether compounds, lubricants and magnetic disks

Abstract

To provide a highly heat-resistant fluoropolyether compound that can maintain a protective surface layer even at high temperatures, and a lubricant and a magnetic disk containing the same.SOLUTION: Provided is a fluoropolyether compound in which three groups containing a perfluoropolyether chain in the main chain are bonded via a trivalent linking group represented by the following formula (1). In formula (1), R1 is a saturated hydrocarbon group having 1 to 3 carbon atoms, a perfluoroalkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or an amino group; A1, A2, and A3 are each independently an aromatic group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a fluoropolyether compound, a lubricant, and a magnetic disk. [Background technology]

[0002] 2. Description of the Related Art In order to increase the storage capacity of magnetic disks such as hard disk drives (HDDs), development of energy-assisted magnetic disks such as thermally assisted magnetic recording (HAMR) is underway.

[0003] In an energy-assisted magnetic disk, in order to control the magnetism of the magnetic disk, energy is applied to the magnetic layer by a laser, microwave, or the like, and the magnetic layer is heated by this energy.

[0004] Surface lubricants for magnetic disks are applied to the outermost surface of the magnetic disk for the purpose of surface protection, but in the case of energy-assisted magnetic disks, the surface lubricants for magnetic disks are also exposed to high temperatures, so there is a demand for highly heat-resistant lubricants that can maintain the surface protective layer even at high temperatures.

[0005] As a technique for improving the heat resistance of a lubricant, a technique for increasing the molecular weight by polymerization (multidentate structure) is known (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2010 / 038773 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the above-mentioned conventional techniques still have room for improvement in terms of heat resistance.

[0008] An object of one aspect of the present invention is to provide a fluoropolyether compound having excellent heat resistance that can maintain a surface protective layer even at high temperatures, and a lubricant and a magnetic disk containing the same. [Means for solving the problem]

[0009] As a result of extensive research to solve the above problems, the present inventors have found that a fluoropolyether compound having a specific structure has high heat resistance and can maintain a surface protective layer even at high temperatures, and have completed the present invention. That is, the present invention includes the following aspects.

[0010] [1] A fluoropolyether compound in which three groups containing a perfluoropolyether chain in the main chain are bonded via a trivalent linking group represented by the following formula (1):

[0011] [ka]

[0012] In formula (1), R1 is a saturated hydrocarbon group having 1 to 3 carbon atoms, a perfluoroalkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or an amino group, and A1, A2, and A3 are each independently an aromatic group.

[0013] [2] The linking group is a trivalent linking group represented by the following formula (2):

[0014] [ka]

[0015]

[0023] In the formula (2), B1, B2, and B3 each independently contain an aliphatic group containing an ether bond.

[0024] The fluoropolyether compound according to [1].

[0016] [3] The fluoropolyether compound according to [1] or [2], represented by the following formula (3):

[0017] [ka]

[0018] In formula (3), R1 represents a saturated hydrocarbon group having 1 to 3 carbon atoms, a perfluoroalkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or an amino group; -(CF2) a each - independently represents a linear or branched perfluoroalkylene group; each a independently represents a real number of 1 to 3; Rf is expressed by the following formula (4):

[0019] [ka]

[0020] In formula (4), b, c, d, e, and f are each independently a real number of 0 to 21 in each Rf, provided that at least one of b, c, d, e, and f is a real number of 1 or more; R2, R3, and R4 are each independently F, CH2OH, CH2OCH2CH(OH)CH2OH, CH2OCH2CH(OH)CH2OCH2CH(OH)CH2OH, CH2O(CH2) g OH, CH2OCH2CH(OH)CH2OC6H4OC6H5, CH2OCH2CH(OH)CH2OC 10 H7, CH2OCH2CH(OH)CH2OC6H4-R5, CH2OCH2CH(OH)CH2O(CH2) h OC6H4-O(CH2) h OH, or CH2OCH2CH(OH)CH2(OCH2CH2) i OC6H4(OCH2CH2) i OH; R5 is hydrogen, an alkoxy group having 1 to 4 carbon atoms, an amino group, a hydroxyl group, or an amide group; g and i are each independently a real number of 1 to 3; and h is each independently a real number of 1 to 6.

[0021] [4] A lubricant comprising the fluoropolyether compound according to any one of [1] to [3].

[0022] [5] A magnetic disk having a recording layer, a protective layer, and a lubricating layer laminated in this order, the lubricating layer containing the lubricant according to [4]. [Effects of the Invention]

[0023] According to one aspect of the present invention, it is possible to provide a fluoropolyether compound having excellent heat resistance, which can maintain a surface protective layer even at high temperatures, and a lubricant and a magnetic disk containing the same. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a cross-sectional view showing the configuration of a magnetic disk according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view showing the configuration of a magnetic disk according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] [1. Fluoropolyether Compounds] In consideration of the above-mentioned problems, the present inventors have conducted extensive research and have focused on a lubricant compound described in Patent Document 1, in which multiple perfluoropolyether groups are bonded via a trivalent linking group having a structure in which three benzene rings and a hydrogen atom are bonded to a carbon atom.

[0026] Lubricant compounds in which multiple perfluoropolyether groups are polymerized by a linking group having a structure in which a hydrogen atom is bonded to a tertiary carbon adjacent to a benzene ring have been thought to be stable when used in magnetic disks. However, when the present inventors conducted heat resistance tests using such lubricant compounds, they found that there was a problem in that low-molecular-weight by-products were generated due to molecular scission and the by-products evaporated. This is thought to be because, upon heating, hydrogen on the tertiary carbon adjacent to the benzene ring was eliminated, causing a structural change, resulting in the scission of the bond between the tertiary carbon and the benzene ring, and the generation of by-products with reduced molecular weight. When low-molecular-weight by-products are generated on a magnetic disk due to such molecular scission, the by-products evaporate, making it difficult to maintain the lubricating film.

[0027] Normally, a linking group in which a low-bulk hydrogen atom is bonded to a tertiary carbon adjacent to a benzene ring is used because bulkiness can be a hindrance when used in a magnetic disk. However, the present inventors used a linking group having a structure in which an alkyl group is bonded to a tertiary carbon adjacent to a benzene ring, and found that even an alkyl group with a carbon number of 1 to 3, which is bulkier than a hydrogen atom, does not pose a hindrance, and has excellent chemical stability, resulting in an unexpected effect of realizing a lubricant that can maintain a lubricating film even when the disk is heated, such as during HAMR.

[0028] That is, the fluoropolyether compound according to one embodiment of the present invention is formed by bonding three groups each containing a perfluoropolyether chain in the main chain via a trivalent linking group represented by the following formula (1).

[0029] [ka]

[0030] In formula (1), R1 is a saturated hydrocarbon group having 1 to 3 carbon atoms, a perfluoroalkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or an amino group, and A1, A2, and A3 are each independently an aromatic group.

[0031] Examples of the saturated hydrocarbon group having 1 to 3 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Examples of the perfluoroalkyl group having 1 to 3 carbon atoms include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, and a perfluoroisopropyl group. Examples of the alkoxy group having 1 to 3 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, and an isopropoxy group.

[0032] Examples of the aromatic group include a phenylene group, a naphthylene group, a biphenyl group, and a diphenyl ether group. The aromatic group may have a substituent. A1, A2, and A3 may be the same or different.

[0033] The group containing a perfluoropolyether chain in its main chain is not particularly limited as long as it contains a perfluoropolyether chain in its main chain. From the viewpoint of heat resistance, the group containing a perfluoropolyether chain in its main chain preferably has a hydroxyl group, an aromatic group, or a combination thereof at its terminal, i.e., the terminal opposite to the portion bonded to the linking group. Examples of the aromatic group include a phenyl group, a naphthyl group, a phenoxyphenyl group, and a thienyl group. The aromatic group may be substituted with an alkoxy group having 1 to 4 carbon atoms, an amino group, a hydroxyl group, a hydroxyalkoxy group having 1 to 6 carbon atoms, or an amide group. When the group containing a perfluoropolyether chain in its main chain contains a hydroxyl group at its terminal, it may contain one, two, three, or four hydroxyl groups. Furthermore, the group containing a perfluoropolyether chain in its main chain may contain any combination of the above-mentioned aromatic group and hydroxyl group. The term "terminal portion" as used herein includes the terminal portion of the group containing the perfluoropolyether chain in the main chain and the portion located on the terminal side of the perfluoropolyether chain.

[0034] The perfluoropolyether chain is not particularly limited, but a more preferred example is Rf represented by the formula (4) described below.

[0035] The three groups comprising the perfluoropolyether chain in the main chain may be the same or different.

[0036] The linking group may be a trivalent linking group represented by the following formula (2).

[0037] [ka]

[0038] In formula (2), B1, B2, and B3 each independently represent an aliphatic group containing an ether bond. Examples of the aliphatic group containing an ether bond include a group containing a linear or branched chain carbon skeleton and having one or more ether bonds in the chain carbon skeleton. The number of carbon atoms in the chain carbon skeleton is not particularly limited. The number of ether bonds is also not particularly limited, as long as it is one or more.

[0039] The aliphatic group containing an ether bond may have a polar group, such as an aromatic group, a hydroxyl group, an amino group, an aldehyde group, a carboxyl group, a thiol group, or a sulfonic acid group.

[0040] A fluoropolyether compound according to one embodiment of the present invention may be, for example, a fluoropolyether compound represented by the following formula (3).

[0041] [ka]

[0042] In formula (3), R1 is the same as R1 in formula (1). In formula (3), -(CF2) a Each - is independently a straight-chain or branched perfluoroalkylene group, and each a is independently a real number of 1 to 3. That is, -(CF2) aEach - can independently be -CF2-, -(CF2)2-, -(CF2)3-, or -CF(CF3)-.

[0043] In formula (3), Rf is a group represented by the following formula (4).

[0044] [ka]

[0045] In formula (4), b, c, d, e, and f in each Rf are independently real numbers of 0 to 21. However, at least one of b, c, d, e, and f is a real number of 1 or greater.

[0046] Examples of the Rf include a demnum skeleton (C3 skeleton): -(OCFCFCF) d -, Fomblin skeleton (C1C2 skeleton): -(OCF2) b (OCF2CF2) c -, C2 skeleton: -(OCF2CF2) c -, C4 skeleton: -(OCF2CF2CF2CF2) e -, Krytox skeleton:-(OCF(CF3)CF2) f - are some examples.

[0047] A more preferred example of Rf is a group in which b, c, d, e, and f in formula (4) are any of the following (i) to (v): The following structure is preferred because it makes the molecular chain flatter.

[0048] (i) b = real number between 2 and 10, and c = real number between 2 and 12, and d~f = 0 (ii) c = a real number between 6 and 12, and b and d to f = 0 (iii) d = a real number between 3 and 8, and b, c, e, and f = 0 (iv) e = real number between 2 and 5, and b to d and f = 0 (v) f = 3 to 8 real numbers, and b to e = 0 In addition, OCF2 and OCF2CF2 can be repeated randomly in the Fomblin skeleton.

[0049] In formula (3), R2, R3, and R4 are each independently F, CH2OH, CHOCH2CH(OH)CH2OH, CHOCH2CH(OH)CH2OCH2CH(OH)CH2OH, CHO(CH2) g OH, CH2OCH2CH(OH)CH2OC6H4OC6H5, CH2OCH2CH(OH)CH2OC 10 H7, CH2OCH2CH(OH)CH2OC6H4-R5, CH2OCH2CH(OH)CH2O(CH2) h OC6H4-O(CH2) h OH, or CH2OCH2CH(OH)CH2(OCH2CH2) i OC6H4(OCH2CH2) i OH, R5 is hydrogen, an alkoxy group having 1 to 4 carbon atoms, an amino group, a hydroxyl group or an amide group, g and i are each independently a real number of 1 to 3, and h is each independently a real number of 1 to 6. Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, a tert-butoxy group and a sec-butoxy group.

[0050] The fluoropolyether compound represented by formula (3) may contain any combination of the above-described a, R1, Rf represented by formula (4), and R2, R3, and R4.

[0051] In the fluoropolyether compound according to one embodiment of the present invention, the number average molecular weight of each of the three groups containing a perfluoropolyether chain in the main chain is preferably 200 to 5000, more preferably 800 to 1500. Here, the number average molecular weight is measured by JNM-ECX400 manufactured by JEOL Ltd. 19 This is a value measured by F-NMR. In NMR measurements, the sample is not diluted with a solvent, but is used as is. The chemical shift reference is substituted with a known peak that is part of the fluoropolyether backbone structure.

[0052] Each of the three groups containing a perfluoropolyether chain in the main chain is a compound having a molecular weight distribution, and the molecular weight distribution (PD) expressed as weight average molecular weight / number average molecular weight is usually 1.0 to 1.5, more preferably 1.0 to 1.3, and even more preferably 1.0 to 1.1. The molecular weight distribution is a characteristic value obtained using a Tosoh HPLC-8220GPC, a Polymer Laboratory column (PLgel Mixed E), an HCFC-based alternative fluorocarbon as the eluent, and a non-functional perfluoropolyether as the reference substance.

[0053] A more specific example of the fluoropolyether compound according to one embodiment of the present invention is a compound represented by the following formula:

[0054] [ka]

[0055] In Compound 1, d is a real number of 3 to 8.

[0056] [ka]

[0057] In Compound 2, c is a real number between 6 and 12.

[0058] [ka]

[0059] In Compound 3, d is a real number of 3 to 8.

[0060] [ka]

[0061] In Compound 4, e is a real number ranging from 2 to 5.

[0062] [ka]

[0063] In Compound 5, c is a real number from 6 to 12.

[0064] [ka]

[0065] In Compound 6, c is a real number from 6 to 12.

[0066] 2. Method for producing fluoropolyether compounds The method for producing the fluoropolyether compound according to one embodiment of the present invention is not particularly limited. The fluoropolyether compound according to one embodiment of the present invention can be obtained, for example, by reacting a linear fluoropolyether compound (hereinafter sometimes referred to as "linear fluoropolyether compound (a)") that contains a perfluoropolyether chain in the main chain and has a hydroxyl group at at least one end with a compound (hereinafter sometimes referred to as "compound (A-1)") that contains a structure represented by the formula (1) and in which A1, A2, and A3 in the formula (1) are each bonded to a group containing an epoxide structure.

[0067] <2-1. Linear fluoropolyether compound (a)> The linear fluoropolyether compound (a) containing the above-mentioned perfluoropolyether chain in the main chain and having a hydroxyl group at at least one end is not particularly limited, but examples thereof include linear fluoropolyether compounds (a-1) having a hydroxyl group at one end and an F atom at the other end (hereinafter, sometimes referred to as "linear fluoropolyether compound (a-1)"); linear fluoropolyether compounds (a-2) having a hydroxyl group at one end and 1, 2, 3 or 4 hydroxyl groups at the other end ( Examples of such compounds include a linear fluoropolyether compound (a-2) (hereinafter sometimes referred to as "linear fluoropolyether compound (a-3)") having a hydroxyl group at one end and a hydroxyalkyl group at the other end (hereinafter sometimes referred to as "linear fluoropolyether compound (a-3)"), and a linear fluoropolyether compound (a-4) (hereinafter sometimes referred to as "linear fluoropolyether compound (a-4)") having a hydroxyl group at one end and an aromatic group and a hydroxyl group at the other end. Here, the term "end" includes the end of the group containing the perfluoropolyether chain in the main chain and the portion located on the end side of the perfluoropolyether chain.

[0068] A more specific example of the linear fluoropolyether compound (a) is a compound represented by the following formula (5). HO-CH2(CF2) a -Rf-O(CF2) a -R (5) In formula (5), -(CF2) a Each "-" is independently a straight-chain or branched perfluoroalkylene group, each "a" is independently a real number of 1 to 3, and Rf is the same as Rf represented by the above formula (4). In formula (5), R is the same as R2, R3, and R4 described above, and is selected from the group consisting of F, CH2OH, CHOCH2CH(OH)CH2OH, CHOCH2CH(OH)CHOCH2CH(OH)CH2OH, and CHO(CH2) g OH, CH2OCH2CH(OH)CH2OC6H4OC6H5, CH2OCH2CH(OH)CH2OC 10H7, CH2OCH2CH(OH)CH2OC6H4-R5, CH2OCH2CH(OH)CH2O(CH2) h OC6H4-O(CH2) h OH, or CH2OCH2CH(OH)CH2(OCH2CH2) i OC6H4(OCH2CH2) i OH; R5 is hydrogen, an alkoxy group having 1 to 4 carbon atoms, an amino group, a hydroxyl group, or an amide group; g and i are each independently a real number of 1 to 3; and h is each independently a real number of 1 to 6.

[0069] The linear fluoropolyether compound (a) represented by the formula (5) may contain any combination of the above-described a, R, and Rf.

[0070] (Linear fluoropolyether compound (a-1)) The linear fluoropolyether compound (a-1), for example, the linear fluoropolyether compound (a-1) in which R is F in formula (5), is not limited thereto, but for example, a compound represented by the following formula can be used. CF3CF2(OCF2CF2) c OCF2CH2OH CF3CF2CF2(OCF2CF2CF2) d OCF2CF2CH2OH CF3CF2CF2CF2(OCF2CF2CF2CF2) e OCF2CF2CF2CH2OH (Linear fluoropolyether compound (a-2)) Among the linear fluoropolyether compounds (a-2), those having a hydroxyl group at one end and one hydroxyl group at the other end (hereinafter, sometimes referred to as "linear fluoropolyether (b)") include, for example, linear fluoropolyether compounds (a-2) in which R in the formula (5) is CH2OH, i.e., HOCH2(CF2) a -Rf-O(CF2) a A linear fluoropolyether represented by —CH2OH can be preferably used, where —(CF2) aEach "-" is independently a linear or branched perfluoroalkylene group, each "a" is independently a real number of 1 to 3, and Rf is the same as Rf represented by the above formula (4).

[0071] A more specific example of the linear fluoropolyether (b) is, for example, HOCH2CF2(OCF2) b (OCF2CF2) c Compound represented by OCF2CH2OH, HOCH2CF2(OCF2CF2) c Compound represented by OCF2CH2OH, HOCH2CF2CF2(OCF2CF2CF2) d Compounds represented by OCF2CF2CH2OH, HOCH2CF2CF2CF2(OCF2CF2CF2CF2) e The compound represented by OCF2CF2CF2CH2OH, HOCH2CF(CF3)(O(CF2CF(CF3)) f -OCF2CF2CF2(O-(CF2CF(CF3)) f The number average molecular weight of these linear fluoropolyethers (b) is usually 200 to 5000, more preferably 800 to 1500. Here, the number average molecular weight is measured by JNM-ECX400 manufactured by JEOL Ltd. 19 The values ​​were measured by F-NMR in the same manner as described above.

[0072] The linear fluoropolyether (b) is a compound having a molecular weight distribution, and the molecular weight distribution (PD) expressed as weight average molecular weight / number average molecular weight is usually 1.0 to 1.5, more preferably 1.0 to 1.3, and even more preferably 1.0 to 1.1. The molecular weight distribution is a value obtained using a Tosoh HPLC-8220GPC in the same manner as described above.

[0073] Among the linear fluoropolyether compounds (a-2), those having a hydroxyl group at one terminal and two, three, or four hydroxyl groups at the other terminal, such as linear fluoropolyether compounds (a-2) in which R in the formula (5) is CHOCHCH(OH)CHOH or CHOCHCH(OH)CHOCHCH(OH)CHOH, can be produced by reacting the linear fluoropolyether (b) having hydroxyl groups at both terminals with a compound (c-1) (hereinafter sometimes referred to as "compound (c-1)") that reacts with the hydroxyl group to form -O-CH-CH(OH)-. The reaction temperature is preferably 20 to 90°C, more preferably 60 to 80°C. The reaction time is preferably 5 to 20 hours, more preferably 10 to 15 hours. The amount of compound (c-1) used is preferably 0.5 to 1.5 equivalents relative to the linear fluoropolyether (b). A reaction accelerator may be used in the reaction. Examples of reaction accelerators include sodium hydroxide, potassium t-butoxide, sodium t-butoxide, and sodium hydride. The reaction may be carried out in a solvent. Examples of the solvent include t-butyl alcohol, dimethylformaldehyde, 1,4-dioxane, dimethyl sulfoxide, and dimethylacetamide. The resulting reaction product may then be purified, for example, by column chromatography. This allows for the production of a linear fluoropolyether compound (a-2) having a hydroxyl group at one end and two, three, or four hydroxyl groups at the other end.

[0074] Examples of the compound (c-1) include compounds having an epoxide structure, such as glycidol, propylene oxide, glycidyl methyl ether, and isobutylene oxide.

[0075] For example, the linear fluoropolyether (b) is HOCH2CF2O(CF2CF2O) cWhen CF2CH2OH is used and glycidol is used as the compound (c-1), the reaction between the two produces the linear fluoropolyether compound (a) HOCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c CF2CH2OH is produced.

[0076] (Linear fluoropolyether compound (a-3)) The linear fluoropolyether compound (a-3) having a hydroxyl group at one end and a hydroxyalkyl group at the other end, for example, a compound represented by the formula (5), wherein R is CHO(CH) g The linear fluoropolyether compound (a-3) is, for example, a compound obtained by reacting the linear fluoropolyether (b) with X(CH2) m It can be produced by reacting X(CH2) with a haloalkyl alcohol (c-2) represented by OH. m In the haloalkyl alcohol (c-2) represented by OH, X is a halogen atom such as chlorine, bromine or iodine, and m is preferably a real number of 1-3.

[0077] More specific examples of the haloalkyl alcohol (c-2) include 2-chloroethanol, 3-chloropropanol, 4-chlorobutanol, 5-chloropentanol, 6-chlorohexanol, 7-chloroheptanol, 8-chlorooctanol, 2-bromoethanol, 3-bromopropanol, 4-bromobutanol, 5-bromopentanol, 6-bromohexanol, 7-bromoheptanol, 8-bromooctanol, 2-iodoethanol, 3-iodopropanol, 4-iodobutanol, 5-iodopentanol, 6-iodohexanol, 7-iodoheptanol, and 8-iodooctanol.

[0078] (Linear fluoropolyether compound (a-4)) A linear fluoropolyether compound (a-4) having a hydroxyl group at one end and an aromatic group and a hydroxyl group at the other end, for example, a compound represented by the formula (5) in which R is CHOCHCH(OH)CHOCHOC, CHOCHCH(OH)CHOC 10 H7, CH2OCH2CH(OH)CH2OC6H4-R5, CH2OCH2CH(OH)CH2O(CH2) h OC6H4-O(CH2) h OH, or CH2OCH2CH(OH)CH2(OCH2CH2) i OC6H4(OCH2CH2) i The linear fluoropolyether compound (a-4) represented by OH (R5 is hydrogen, an alkoxy group having 1 to 4 carbon atoms, an amino group, a hydroxyl group, or an amide group, h is each independently a real number of 1 to 6, and i is each independently a real number of 1 to 3) can be produced, for example, by reacting the linear fluoropolyether (b) with a phenoxy compound (c-3) having an epoxide structure.

[0079] Examples of the phenoxy compound (c-3) having an epoxide structure include compounds represented by the following formulae (c-3-1), (c-3-2), (c-3-3) and (c-3-4).

[0080] [ka]

[0081] For example, the linear fluoropolyether (b) may be HOCH2CF2O(CF2CF2O) c When CF2CH2OH is used and compound (c-3-1) is used as compound (c-3), the reaction between the two produces the linear fluoropolyether compound (a) CH3OC6H4OCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c CF2CH2OH is produced.

[0082] The reaction temperature, reaction time, amount of the phenoxy compound (c-3) having an epoxide structure used, reaction accelerator, solvent, and post-treatment in the reaction between the linear fluoropolyether (b) and the phenoxy compound (c-3) having an epoxide structure are as follows: , conversion Compound (c- 1 ) is similar to the reaction with

[0083] <2-2. Compound (A-1) containing a structure represented by the formula (1) and having a group containing an epoxide structure bonded to each of A1, A2, and A3 in the formula (1)> The compound (A-1) can be obtained by epoxidizing some of the hydroxyl groups in the molecule of the compound (A-2) (for example, the compounds (A-2-1) to (A-2-6) shown below).

[0084] (A-2-1): 1,1,1-tris(4-hydroxyphenyl)ethane (A-2-2): 1,1,1-tris(4-hydroxyphenyl)propane (A-2-3): P,P',P''-triphenolaminomethane

[0085] [ka]

[0086] (A-2-4): Tris(4-hydroxyphenyl)methanol

[0087] [ka]

[0088] (A-2-5): 1,1,1-tris(4-hydroxyphenyl)methylpropane

[0089] [ka]

[0090] (A-2-6): 1,1,1-tris(4-hydroxyphenyl)butane

[0091] [ka]

[0092] For example, when 1,1,1-tris(4-hydroxyphenyl)ethane is used as compound (A-2) and the hydroxyl group is epoxidized, 1,1,1-tris(4-hydroxyphenyl)ethane triglycidyl ether (D-1) is generated as compound (A-1). When 1,1,1-tris(4-hydroxyphenyl)propane is used as compound (A-2) and the hydroxyl group is epoxidized, 2,2',2''-[propylidinetris(4,1-phenyleneoxymethylene)]tris[oxirane] (D-2) is generated as compound (A-1).

[0093] [ka]

[0094] <2-3. Synthesis of fluoropolyether compound of the present invention> The fluoropolyether compound according to one embodiment of the present invention can be obtained, for example, by reacting the above-mentioned linear fluoropolyether compound (a) with the above-mentioned compound (A-1).

[0095] Specifically, for example, the linear fluoropolyether compound (a) and the compound (A-1) are reacted in the presence of a base. The reaction temperature is preferably 20 to 90°C, more preferably 60 to 80°C. The reaction time is preferably 5 to 120 hours, more preferably 30 to 70 hours. The amounts of the linear fluoropolyether compound (a) and the base used are preferably 3 to 15 equivalents of the linear fluoropolyether compound (a) and 0.3 to 3.0 equivalents of the base relative to the compound (A-1). Examples of the base that can be used include alkaline compounds such as sodium t-butoxide, potassium t-butoxide, sodium hydroxide, potassium hydroxide, and sodium hydride. The reaction may be carried out in a solvent. Examples of the solvent that can be used include t-butanol, toluene, xylene, and meta-xylene hexafluoride. The resulting reaction product may then be washed with water and dehydrated. This provides a fluoropolyether compound according to one embodiment of the present invention.

[0096] [3. Lubricants] The lubricant according to one embodiment of the present invention contains the fluoropolyether compound according to one embodiment of the present invention. The fluoropolyether compound can be used alone as a lubricant, or the lubricant can be a mixture of the fluoropolyether compound and other components in any ratio within a range that does not impair the performance of the lubricant.

[0097] Examples of the other components include known lubricants for magnetic disks such as Fomblin (registered trademark) Zdol (manufactured by Solvay Solexis), Ztetraol (manufactured by Solvay Solexis), Demnum (registered trademark) (manufactured by Daikin Industries, Ltd.), and Krytox (registered trademark) (manufactured by Dupont), as well as PHOSFAROL A20H (MORESCO PHOSFAROL A20H) (manufactured by MORESCO) and MORESCO PHOSFAROL D-4OH (manufactured by MORESCO).

[0098] The lubricant can be used as a lubricant for recording media to improve the sliding characteristics of magnetic disks. It can also be used as a lubricant for recording media other than magnetic disks, such as magnetic tapes, in other recording devices that involve sliding between the recording media and the head. Furthermore, it can be used as a lubricant for devices that have sliding parts, not limited to recording devices.

[0099] [4. Magnetic Disk] 1, a magnetic disk 1 according to one embodiment of the present invention includes a recording layer 4, a protective film layer (protective layer) 3, and a lubricating layer 2, which are arranged on a non-magnetic substrate 8. The lubricating layer 2 contains the above-mentioned lubricant.

[0100] 2, the magnetic disk may include an underlayer 5 disposed under the recording layer 4, one or more soft magnetic underlayers 6 disposed under the underlayer 5, and an adhesion layer 7 disposed under the one or more soft magnetic underlayers 6. All of these layers may be formed on a non-magnetic substrate 8 in one embodiment.

[0101] Each layer of the magnetic disk 1, except for the lubricating layer 2, may comprise a material known in the art to be suitable for a particular layer of a magnetic disk. For example, the recording layer 4 may be made of an alloy of ferromagnetic elements such as iron, cobalt, or nickel, plus chromium, platinum, or tantalum, or an oxide thereof. The protective layer 3 may be made of carbon, Si3N4, SiC, or SiO2. The non-magnetic substrate 8 may be made of an aluminum alloy, glass, or polycarbonate.

[0102] 5. Magnetic Disk Manufacturing Method A method for manufacturing a magnetic disk according to one aspect of the present invention includes a step of forming a lubricating layer by laminating a lubricant according to one embodiment of the present invention onto the exposed surface of a protective layer of a laminate formed by laminating a recording layer and a protective layer.

[0103] The method for forming a lubricating layer by laminating the lubricant on the exposed surface of the protective layer of a laminate formed by laminating a recording layer and a protective layer is not particularly limited. A preferred method for laminating a lubricant on the exposed surface of the protective layer is to dilute the lubricant in a solvent and then laminate the lubricant. Examples of solvents include PF-5060, PF-5080, HFE-7100, and HFE-7200 manufactured by 3M, and Vertrel-XF (registered trademark) manufactured by DuPont. The concentration of the lubricant after dilution with the solvent is preferably 0.001% by weight to 1% by weight, more preferably 0.005% by weight to 0.5% by weight, and even more preferably 0.005% by weight to 0.1% by weight. If the concentration of the lubricant after dilution with the solvent is 0.005% by weight to 0.1% by weight, the interaction between lubricant molecules can be weakened, making it easier to form a uniform lubricating film.

[0104] The recording layer and the protective layer may be formed in this order, and the lubricant may be laminated on the exposed surface of the protective layer, followed by ultraviolet irradiation or heat treatment.

[0105] By performing ultraviolet irradiation or heat treatment, a stronger bond can be formed between the lubricating layer and the exposed surface of the protective layer, and evaporation of the lubricant due to heating can be prevented. When performing ultraviolet irradiation, it is preferable to use ultraviolet light with a dominant wavelength of 185 nm or 254 nm in order to activate the exposed surface without affecting the deep parts of the lubricating layer and the protective layer. When performing heat treatment, the temperature is preferably 60 to 170°C, more preferably 80 to 170°C, and even more preferably 80 to 150°C. [Example]

[0106] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0107] Example 1: (CFCFCFO(CFCFCFO) d Synthesis of CFCFCHOCHCH(OH)CHOC)CCH (Compound 1) Compound 1 was synthesized as follows: Under an argon atmosphere, 6.4 g of t-butyl alcohol, CFCFCFO (CFCFCFO) d 16 g of a fluoropolyether represented by CFCFCHOH (number average molecular weight 1026, molecular weight distribution 1.24), 0.1 g of sodium t-butoxide, and 0.8 g of a compound obtained by epoxidizing 1,1,1-tris(4-hydroxyphenyl)ethane (1,1,1-tris(4-hydroxyphenyl)ethane triglycidyl ether) were stirred at 70°C for 80 hours. The resulting reaction product was then washed with water, dehydrated, and further purified by distillation to obtain 3.9 g of compound 1.

[0108] Compound 1 is a pale yellow, transparent, viscous substance with a density of 1.73 g / cm at 20°C. 3 The results of identification of Compound 1 using NMR are shown below.

[0109] 19 F-NMR (solvent: hexafluorobenzene, reference material: OCFCFCFO in the product at -129.7 ppm) δ=-129.7ppm [26F, -OCF2CF2CF2O-] δ=-83.7 ppm [52F, -OCF2CF2CF2O-] δ=-124.2ppm [6F, -OCF2CF2CH2OCH2CH(OH)CH2O-] δ=-86.5ppm [6F, -OCF2CF2CH2OCH2CH(OH)CH2O-] δ=-82.4ppm [6F, -OCF2CF2CF3] δ=-130.7ppm [6F, -OCF2CF2CF3] δ=-84.7ppm [6F, -OCF2CF2CF3] 19 F-NMR revealed that compound 1 had d=4.3.

[0110] 1H-NMR (solvent: hexafluorobenzene, reference material: DO) δ=4.0~4.9ppm〔21H,(CF3CF2CF2O(CF2CF2CF2O) d CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=6.9~7.6ppm〔12H,(CF3CF2CF2O(CF2CF2CF2O) d CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=2.5ppm〔3H,(CF3CF2CF2O(CF2CF2CF2O) d CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=2.8ppm〔3H,(CF3CF2CF2O(CF2CF2CF2O) d CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3].

[0111] Example 2: (HOCHCH(OH)CHOCHCFO(CFCFO) c Synthesis of CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3 (Compound 2) Compound 2 was synthesized as follows: Under an argon atmosphere, 251 g of t-butyl alcohol, HOCH2CF2O(CF2CF2O) c585 g of fluoropolyether (number average molecular weight 1234, molecular weight distribution 1.24) represented by CF2CH2OH, 5.2 g of potassium t-butoxide, and 74.1 g of glycidol were stirred at 70°C for 15 hours. The resulting reaction product was then washed with water, dehydrated, and purified by silica gel column chromatography to obtain 277 g of fluoropolyether (average molecular weight 1306) having one hydroxyl group at one end and two hydroxyl groups at the other end. 92 g of the resulting fluoropolyether was dissolved in 39.8 g of t-butyl alcohol, and 0.2 g of sodium t-butoxide and 3.6 g of a compound (1,1,1-tris(4-hydroxyphenyl)ethane triglycidyl ether) obtained by epoxidizing 1,1,1-tris(4-hydroxyphenyl)ethane were added. The mixture was stirred at 70°C for 68 hours. Thereafter, the obtained reaction product was washed with water, and then the washed reaction product was dehydrated, and the dehydrated reaction product was purified by distillation to obtain 30 g of Compound 2.

[0112] Compound 2 is a viscous substance with a density of 1.73 g / cm at 20°C. 3 The results of identification of Compound 2 using NMR are shown below.

[0113] 19 F-NMR (solvent: none, reference material: OCFCFO in the product is set at -89.1 ppm) δ=-89.1ppm〔113F,-OCF2CF2O-〕 δ=-79.0ppm [12F,-OCF2CH2OCH2CH(OH)CH2O-, -OCF2CH2OCH2CH(OH)CH2OH] 19 F-NMR revealed that compound 2 had c=9.4.

[0114] 1 H-NMR (solvent: none, reference material: DO) δ=4.0~4.9ppm〔42H,(HOCH2CH(OH)CH2OCH2CF2O(CF2CF2O) cCF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=6.9~7.6ppm〔12H,(HOCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=2.5ppm〔3H,(HOCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=2.8ppm〔9H,((HOCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3].

[0115] Example 3: (HOCHCH(OH)CHOCHCFCFO(CFCFCFO) d Synthesis of CFCFCHOCHCH(OH)CHOCH)CCH (Compound 3) HOCHCFO(CFCFO) used in Example 2 c Instead of the fluoropolyether represented by CF2CH2OH, HOCH2CF2CF2O (CF2CF2CF2O) d 30 g of Compound 3 was obtained in the same manner as in Example 2, except that a fluoropolyether represented by CF2CF2CH2OH was used.

[0116] Compound 3 is a pale yellow, transparent viscous substance with a density of 1.73 g / cm at 20°C. 3 The results of identification of compound 3 using NMR are shown below.

[0117] 19 F-NMR (solvent: none, reference material: OCFCFCFO in the product is set at -129.7 ppm) δ=-129.7ppm [34F, -OCF2CF2CF2O-] δ=-83.7 [67F, -OCF2CF2CF2O-] δ=-124.2ppm [12F, -OCF2CF2CH2OCH2CH(OH)CH2O-, -OCF2CF2CH2OCH2CH(OH)CH2OH] δ=-86.5ppm [12F, -OCF2CF2CH2OCH2CH(OH)CH2O-, -OCF2CF2CH2OCH2CH(OH)CH2OH] 19 F-NMR revealed that compound 3 had d=5.6.

[0118] 1 H-NMR (solvent: none, reference material: DO) δ=4.0~4.9ppm〔42H,(HOCH2CH(OH)CH2OCH2CF2CF2O(CF2CF2CF2O) d CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=6.9~7.6ppm〔12H,(HOCH2CH(OH)CH2OCH2CF2CF2O(CF2CF2CF2O) d CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=2.5ppm〔3H,(HOCH2CH(OH)CH2OCH2CF2CF2O(CF2CF2CF2O) d CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=2.8ppm〔9H,((HOCH2CH(OH)CH2OCH2CF2CF2O(CF2CF2CF2O) d CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3].

[0119] Example 4: (HOCHCH(OH)CHOCHCFCFCFO(CFCFCFCFO) e Synthesis of CF2CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3 (Compound 4) HOCHCFO(CFCFO) used in Example 2 c Instead of the fluoropolyether represented by CF2CH2OH, HOCH2CF2CF2CF2O (CF2CF2CF2CF2O)e 33 g of Compound 4 was obtained in the same manner as in Example 2, except that a fluoropolyether represented by CF2CF2CF2CH2OH was used.

[0120] Compound 4 is a pale yellow, transparent viscous substance with a density of 1.73 g / cm at 20°C. 3 The results of identification of compound 4 using NMR are shown below.

[0121] 19 F-NMR (solvent: none, reference material: OCFCFCFCFO in the product is set at -125.8 ppm) δ=-83.7 ppm [64F, -OCF2CF2CF2CF2O-, -OCF2CF2CF2CH2OCH2CH(OH)CH2O-, -OCF2CF2CF2CH2OCH2CH (OH)CH2OH δ=-123.3ppm [12F, -OCF2CF2CF2CH2OCH2CH(OH)CH2O-, -OCF2CF2CF2CH2OCH2CH(OH)CH2OH] δ=-125.8ppm [52F, -OCF2CF2CF2CF2O-] δ=-127.6ppm [12F, -OCF2CF2CF2CH2OCH2CH(OH)CH2O-, -OCF2CF2CF2CH2OCH2CH(OH)CH2OH] 19 F-NMR revealed that compound 4 had e=4.3.

[0122] 1 H-NMR (solvent: none, reference material: DO) δ=4.0~4.9ppm〔42H,(HOCH2CH(OH)CH2OCH2CF2CF2CF2O(CF2CF2CF2CF2O) e CF2CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=6.9~7.6ppm〔12H,(HOCH2CH(OH)CH2OCH2CF2CF2CF2O(CF2CF2CF2CF2O) eCF2CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=2.5ppm〔3H,(HOCH2CH(OH)CH2OCH2CF2CF2CF2O(CF2CF2CF2CF2O) e CF2CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=2.8ppm〔9H,((HOCH2CH(OH)CH2OCH2CF2CF2CF2O(CF2CF2CF2CF2O) e CF2CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3].

[0123] Example 5: (CH3OC6H4OCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c Synthesis of CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3 (Compound 5) 40 g of compound 5 was obtained in the same manner as in Example 2, except that the compound represented by (c-3-1) was used instead of glycidol used in Example 2. Compound 5 was a white waxy solid, and had a density of 1.76 g / cm at 20°C. 3 The results of identification of Compound 5 using NMR are shown below.

[0124] 19 F-NMR (solvent: none, reference material: OCFCFO in the product is set at -89.1 ppm) δ=-89.1ppm〔108F,-OCF2CF2O-〕 δ=-79.0ppm [12F,-OCF2CH2OCH2CH(OH)CH2O-, -OCF2CH2OCH2CH(OH)CH2OC6H4OCH3] 19 F-NMR revealed that compound 5 had c=9.0.

[0125] 1 H-NMR (solvent: none, reference material: DO) δ=4.0~4.9ppm〔51H,(CH3OC6H4OCH2CH(OH)CH2OCH2CF2O(CF2CF2O)c CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=6.5~7.6ppm〔24H,(CH3C6H4OCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=2.5ppm〔3H,(CH3C6H4OCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=2.8ppm〔6H,(CH3C6H4OCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3].

[0126] Example 6: (HOCH2CH2OC6H4OCH2CH2OCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c Synthesis of CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3 (Compound 6) 46 g of Compound 6 was obtained in the same manner as in Example 2, except that the compound represented by (c-3-4) was used instead of glycidol used in Example 2. Compound 6 was a white waxy solid, and had a density of 1.76 g / cm at 20°C. 3 The results of identification of Compound 6 using NMR are shown below.

[0127] 19 F-NMR (solvent: none, reference material: OCFCFO in the product is set at -89.1 ppm) δ=-89.1ppm〔104F,-OCF2CF2O-〕 δ=-79.0ppm [12F,-OCF2CH2OCH2CH(OH)CH2O-, -OCF2CH2OCH2CH(OH)CH2OCH2CH2OC6H4OCH2CH2OH] 19 F-NMR revealed that compound 6 had c=8.7.

[0128] 1 H-NMR (solvent: none, reference material: DO) δ=3.5~4.9ppm〔66H,(HOCH2CH2OC6H4OCH2CH2OCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=6.5~7.6ppm〔24H,(HOCH2CH2OC6H4OCH2CH2OCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=2.5ppm〔3H,(HOCH2CH2OC6H4OCH2CH2OCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3〕 δ=2.8ppm〔9H,(HOCH2CH2OC6H4OCH2CH2OCH2CH(OH)CH2OCH2CF2O(CF2CF2O) c CF2CH2OCH2CH(OH)CH2OC6H4)3CCH3].

[0129] Comparative Examples 1 to 3 For comparison, Lubricant 7 (Comparative Example 1), Lubricant 8 (Comparative Example 2), and Lubricant 9 (Comparative Example 3) were used, each having a central skeleton in which three aromatic rings are bonded via a tertiary carbon. The structures of the compounds used as Lubricants 7, 8, and 9 are shown below. Lubricant 8 (Comparative Example 2) and Lubricant 9 (Comparative Example 3) have alkoxy groups at three terminals within the lubricant.

[0130] <Lubricant 7> (CF3CF2CF2O(CF2CF2CF2O) d CF2CF2CH2OCH2CH(OH)CH2OC6H4)3CH Here, d is 5.8.

[0131] <Lubricant 8> (HOCH2CH(OH)CH2OCH2CF2CF2O(CF2CF2CF2O) dCF2CF2CH2OCH2CH(OH)CH2OC6H4)3CH where d is 4.6.

[0132] <Lubricant 9> (HOCH2CF2O(CF2O) b (CF2CF2O) c CF2CH2OCH2CH(OH)CH2OC6H4)3CH Here b is 4.5 and c is 5.4.

[0133] [Evaluation of heat resistance] Five mg of each compound obtained in the examples and comparative examples was weighed into a platinum sample pan and subjected to thermogravimetry. The measurements were carried out in a nitrogen atmosphere, with the temperature rising from 30°C to 550°C at a rate of 2°C / min. To compare heat resistance, the temperature was read when the weight of the compound had decreased by 10%.

[0134] Table 1 below shows the results of measuring the temperature at which the compound lost 10% of its weight.

[0135] [Table 1]

[0136] As shown in Table 1, compounds 1 to 6 obtained in Examples 1 to 6, respectively, which used linking groups having a structure in which an alkyl group is bonded to a tertiary carbon adjacent to a benzene ring, have a higher 10% thermal weight loss temperature and superior heat resistance than the lubricants in the comparative examples which used trivalent linking groups having a structure in which three benzene rings and a hydrogen atom are bonded to a carbon atom. [Industrial Applicability]

[0137] The fluoropolyether compound according to one embodiment of the present invention can be suitably used as a lubricant for magnetic disks. [Explanation of symbols]

[0138] 1. Magnetic disk 2 Lubricating layer 3 Protective film layer (protective layer) 4 Recording Layer 5 Lower layer 6 Soft magnetic underlayer 7 Adhesive layer 8 Non-magnetic substrate

Claims

1. A fluoropolyether compound in which three groups containing a perfluoropolyether chain in the main chain are bonded to a trivalent linking group represented by the following formula (2): 【Chemistry 1】 In formula (2), R １ is a saturated hydrocarbon group having 1 to 3 carbon atoms or a perfluoroalkyl group having 1 to 3 carbon atoms, and A １ , A ２ , and A ３ are each independently an aromatic group; B １ , B ２ , and B ３ are each independently an aliphatic group consisting of a linear or branched chain carbon skeleton and having one or more ether bonds in the chain carbon skeleton, 【Chemistry 2】 and respectively mean the bonding position to the group containing a perfluoropolyether chain in the main chain.

2. A fluoropolyether compound represented by the following formula (3): 【Transformation 3】 In formula (3), R １ is a saturated hydrocarbon group having 1 to 3 carbon atoms or a perfluoroalkyl group having 1 to 3 carbon atoms, -(C a F 2a )- each independently represents a linear or branched perfluoroalkylene group, and each a independently represents a real number of 1 to 3; Rf is represented by the following formula (4): 【Chemistry 4】 In formula (4), b, c, d, e, and f are independently real numbers of 0 to 21 in each Rf, provided that at least one of b, c, d, e, and f is a real number of 1 or more; R ２ , R ３ , and R ４ are each independently F, CH ２ OH, CH ２ OCH ２ CH(OH)CH ２ OH, CH ２ OCH ２ CH(OH)CH ２ OCH ２ CH(OH)CH ２ OH, CH ２ O (CH ２ ) ｇ OH, CH ２ OCH ２ CH(OH)CH ２ O.C. ６ H ４ O.C. ６ H ５ , C.H. ２ OCH ２ CH(OH)CH ２ O.C. １０ H ７ , C.H. ２ OCH ２ CH(OH)CH ２ O.C. ６ H ４ -R ５ , C.H. ２ OCH ２ CH(OH)CH ２ O (CH ２ ) ｈ O.C. ６ H ４ -O(CH ２ ) ｈ OH or CH ２ OCH ２ CH(OH)CH ２ (OCH ２ CH ２ ) i O.C. ６ H ４ (OCH ２ CH ２ ) i OH and R ５ represents hydrogen, an alkoxy group having 1 to 4 carbon atoms, an amino group, a hydroxyl group, or an amide group; g and i each independently represent a real number from 1 to 3; and h each represents They are independently real numbers from 1 to 6.

3. A lubricant comprising the fluoropolyether compound according to claim 1 or 2.

4. A magnetic disk having a recording layer, a protective layer, and a lubricating layer laminated in this order, The magnetic disk, wherein the lubricating layer comprises the lubricant according to claim 3 .

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