Fluorine-containing ether compound, lubricant for magnetic recording medium, and magnetic recording medium

Abstract

A fluorine-containing ether compound represented by the following formula. (In the formula, R1 to R2-CH2-R3 [-CH2-R4-CH2-R3] n-CH2-R5-R6, n is an integer of 0 to 2. And R3 is a perfluoropolyether chain. R4, R2, and R5 each represents a divalent linking group having one or more polar groups. And R2 and R5 have an oxygen atom at the end bonded to R1 or R6. R1 and R6 represent a hydrogen atom or an organic group having 1 to 50 carbon atoms. And at least one of R1 and R6 is represented by formula (2). One of X and Y is C = O, and the other is-NH-and-NR7-(R7 is a hydrocarbon group having 1-8 carbon atoms). ) or-O-. Q represents a 5-to 8-membered heterocyclic structure formed by X and Y together with a carbon atom contained in a linking group represented by a dotted-line arc. And Z is 0 to 5 substituent groups. > # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a fluorine-containing ether compound, a lubricant for a magnetic recording medium, and a magnetic recording medium.

[0002] This application claims priority based on Japanese Patent Application No. 2023-024274 filed in Japan on February 20, 2023, the contents of which are incorporated herein. Background Art

[0003] In order to increase the recording density of magnetic recording and reproducing devices, development of magnetic recording media suitable for high recording density is underway.

[0004] In the past, as a magnetic recording medium, there is a magnetic recording medium obtained by forming a recording layer on a substrate and forming a protective layer of carbon or the like on the recording layer. The protective layer protects the information recorded in the recording layer and improves the sliding property of the magnetic head. However, the durability of the magnetic recording medium cannot be fully obtained by merely arranging the protective layer on the recording layer. Therefore, usually, a lubricant is applied on the surface of the protective layer to form a lubricating layer.

[0005] As a lubricant used in forming a lubricating layer of a magnetic recording medium, for example, a lubricant has been proposed, which contains a compound having a polar group such as a hydroxyl group or an amino group at the end of a fluorine-based polymer having a repeating structure containing -CF2-. (For example, see Patent Documents 1 to 5.)

[0006] Patent Document 1 discloses a fluorine-containing ether compound in which a divalent linking group having a polar group is linked to both ends of a perfluoropolyether chain, and a terminal group having a heterocyclic ring is bonded to both ends.

[0007] Patent document 2 discloses a fluorine-containing ether compound, in which divalent linking groups having polar groups are connected to both ends of a perfluoropolyether chain, and at least one of the two ends is bonded to a terminal group, wherein the terminal group is an organic group having 1 to 8 carbon atoms and at least one hydrogen atom of the organic group is substituted by a group having an amide bond.

[0008] Patent Documents 3 and 4 disclose a fluorine-containing ether compound in which a divalent linking group having a polar group is linked to both ends of a perfluoropolyether chain, and a terminal group having an aromatic ring is bonded to one or both of the two ends.

[0009] Patent Document 5 discloses a compound having a skeleton in which a perfluoropolyether is bonded to both sides of an aliphatic hydrocarbon chain having a hydroxyl group in the center of the molecule, and describes that the compound may have an aromatic ring at the terminal.

[0010] Prior art literature

[0011] Patent Literature

[0012] Patent Document 1: International Publication No. 2018 / 139174 (A)

[0013] Patent Document 2: International Publication No. 2019 / 039265 (A)

[0014] Patent Document 3: Japanese Patent No. 5909837 (B)

[0015] Patent Document 4: Japanese Patent No. 6040455 (B)

[0016] Patent Document 5: Japanese Patent No. 6804981 (B) Summary of the invention

[0017] Problems to be solved by the invention

[0018] In magnetic recording and reproducing devices, it is required to further reduce the flying height of the magnetic head. Therefore, it is necessary to make the thickness of the lubricating layer in the magnetic recording medium thinner.

[0019] But, usually, if the thickness of lubricating layer is thinned, then there is the tendency that the coating property of lubricating layer reduces, the chemical substance resistance of magnetic recording medium reduces.In addition, if the thickness of lubricating layer is thinned, then the lubricating layer that has coated the protective layer surface and the adhesion of protective layer are not enough, and the fluorine-containing ether compound in lubricating layer is easily attached to the adhesion of magnetic head.

[0020] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fluorine-containing ether compound which can form a lubricating layer having excellent chemical resistance and suppressed adhesion even when the thickness is reduced, and which can be suitably used as a material for a lubricant for a magnetic recording medium.

[0021] An object of the present invention is to provide a lubricant for a magnetic recording medium, comprising the fluorine-containing ether compound of the present invention.

[0022] An object of the present invention is to provide a magnetic recording medium having excellent reliability and durability and provided with a lubricating layer containing the fluorinated ether compound of the present invention.

[0023] Means for solving problems

[0024] The present invention includes the following aspects.

[0025] [1] A fluorine-containing ether compound characterized by being represented by the following formula (1).

[0026] R 1 -R 2 -CH2-R 3 [-CH2-R 4 -CH2-R 3] n -CH2-R 5 -R 6 (1)

[0027] (In formula (1), n ​​is an integer from 0 to 2. 3 is a perfluoropolyether chain. (n+1) R 3 They may be partially or completely the same, or they may be different. 4 is a divalent linking group having one or more polar groups. When n is 2, the two R 4 Can be the same or different. 2 and R 5 is a divalent linking group having one or more polar groups. 2 With R 5 Can be the same or different. 2 In the R 1 The bonding end has an oxygen atom. 5 In the R 6 The bonding end has an oxygen atom. 1 and R 6 For R 2 or R 5 The oxygen atom possessed is bonded to an organic group having 1 to 50 carbon atoms or a hydrogen atom. 1 With R 6 Can be the same or different. 1 and R 6 At least one of them is a structure represented by the following formula (2).

[0028]

[0029] In formula (2), one of X and Y is a carbonyl group (C=O), and the other is -NH-, -NR 7 -(R 7 represents a hydrocarbon group having 1 to 8 carbon atoms. ) or -O-. Q represents that the carbon atoms contained in the connecting group represented by the arc of the dotted line form a heterocyclic structure of a 5- to 8-membered ring together with X and Y. Z represents 0 to 5 substituents. Z is each independently an organic group having 1 to 8 carbon atoms. Z can be bonded to any carbon atom constituting the two rings in formula (2) (excluding the carbonyl carbon atom of X or Y). When there are more than 2 Zs, the two Zs can be bonded to each other to form a ring structure. Any one of the carbon atoms constituting the two rings in formula (2) (excluding the carbonyl carbon atom of X or Y) is bonded to R 2 or R 5 The oxygen atom at the end of the

[0030] [2] The fluorine-containing ether compound according to [1], wherein the formula (2) is a structure represented by the following formula (2-1).

[0031]

[0032] (In formula (2-1), one of X and Y is a carbonyl group (C=O), and the other is -NH-, -NR 7 -(R 7 represents a hydrocarbon group having 1 to 8 carbon atoms. ) or -O-. Z is 0 to 5 substituents. Z is each independently an organic group having 1 to 8 carbon atoms. Z may be bonded to any carbon atom constituting the two rings in formula (2-1) (excluding the carbonyl carbon atom of X or Y). When there are 2 or more Zs, the two Zs may be bonded to each other to form a ring structure. Any one of the carbon atoms constituting the two rings in formula (2-1) (excluding the carbonyl carbon atom of X or Y) is bonded to R 2 or R 5 The oxygen atom at the end of the

[0033] [3] The fluorinated ether compound according to [1] or [2], wherein R in the formula (1) 1 With R 6 same.

[0034] [4] The fluorinated ether compound according to [1] or [2], wherein R in the formula (1) 1 and R 6 One of them is a structure represented by the formula (2), and the other is not a structure represented by the formula (2) and is an organic group having at least one double bond or triple bond, an alkyl group having 1 to 8 carbon atoms which may have a substituent, or a hydrogen atom.

[0035] [5] The fluorine-containing ether compound according to any one of [1] to [4], wherein the organic group in Z in the formula (2) is selected from an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkyl group substituted with an aryl group, and an alkoxy group.

[0036] [6] The fluorinated ether compound according to any one of [1] to [5], wherein R in the formula (1) 2 , R 4 and R 5 The polar groups in are all hydroxyl groups.

[0037] [7] The fluorinated ether compound according to any one of [1] to [5], wherein R in the formula (1) 2 , R 4 and R 5 Some or all of the polar groups in are hydroxyl groups, R 2 The hydroxyl groups, R 4 The hydroxyl groups and R 5 The total number of hydroxyl groups contained in the polyol is 2 to 8.

[0038] [8] The fluorinated ether compound according to any one of [1] to [7], wherein R in the formula (1) 2 and R 5 Each is independently a linking group represented by the following formula (3).

[0039]

[0040] (In formula (3), p represents an integer of 1 to 3. q represents an integer of 1 to 5. r represents an integer of 1 to 5. When p is 2 or more, the combination of q and r in each structural unit may be the same or different. In formula (3), the oxygen atom at the left terminal and the oxygen atom arranged in R in formula (1) are 2 or R 5 R 1 In formula (3), the oxygen atom at the right terminal is bonded to the group arranged at R in formula (1). 2 or R 5 R 6 The side groups are bonded.)

[0041] [9] The fluorinated ether compound according to any one of [1] to [8], wherein R in the formula (1) 2 is a linking group represented by the following formula (3-1) or (3-2), wherein R 5 It is a linking group represented by the following formula (3-3) or (3-4).

[0042]

[0043] (p1 in formula (3-1) represents an integer of 1 to 3. q1 in formula (3-2) represents an integer of 2 to 4. In formulas (3-1) and (3-2), the oxygen atom at the left terminal and R in formula (1) are 1 Bonding. )

[0044]

[0045] (p2 in formula (3-3) represents an integer of 1 to 3. r2 in formula (3-4) represents an integer of 2 to 4. In formulas (3-3) and (3-4), the oxygen atom at the right terminal and R in formula (1) are 6 Bonding. )

[0046]

[10] The fluorinated ether compound according to any one of [1] to [9], wherein in the formula (1), (n+1) R 3 is the same, R 1 -R 2 -With R 6 -R 5 -are identical.

[0047]

[11] The fluorinated ether compound according to any one of [1] to

[10] , wherein the n R 4 Each is independently a linking group represented by the following formula (4).

[0048]

[0049] (In formula (4), s represents an integer of 1 to 3. t represents an integer of 1 to 5. u represents an integer of 1 to 5. When s is 2 or more, the combination of t and u in each structural unit may be the same or different. In formula (4), the oxygen atom at the left terminal and the oxygen atom arranged in R in formula (1) are 4 R 1 In formula (4), the oxygen atom at the right terminal is bonded to the group arranged at R in formula (1). 4 R 6 The side groups are bonded.)

[0050]

[12] The fluorinated ether compound according to any one of [1] to

[11] , wherein the n R 4 Each independently represents a linking group represented by any one of the following formulae (4-1) to (4-3).

[0051]

[0052] (In formula (4-1), s1 represents an integer from 1 to 3.)

[0053] (t1 in formula (4-2) represents an integer of 2 to 4. In formula (4-2), the oxygen atom at the left terminal is bonded to R in formula (1). 4 R 1 methylene groups adjacent to the side.)

[0054] (u1 in formula (4-3) represents an integer of 2 to 4. In formula (4-3), the oxygen atom at the right terminal is bonded to R 4 R 6 methylene groups adjacent to the side.)

[0055]

[13] The fluorinated ether compound according to any one of [1] to

[12] , wherein the (n+1) R in the formula (1) 3 Each is independently a perfluoropolyether chain represented by the following formula (5).

[0056] -(CF2) w1 -O-(CF2O) w2 -(CF2CF2O) w3 -(CF2CF2CF2O) w4 -(CF2CF2CF2CF2O) w5-(CF2) w6 -(5)

[0057] (In formula (5), w2, w3, w4, and w5 represent average polymerization degrees, and each independently represents 0 to 20. However, the case where w2, w3, w4, and w5 are all 0 at the same time is excluded. w1 and w6 represent the average value of the number of CF2, and each independently represents 1 to 3. The arrangement order of the repeating units (CF2O), (CF2CF2O), (CF2CF2CF2O), and (CF2CF2CF2CF2O) in formula (5) is not particularly limited.)

[0058]

[14] The fluorinated ether compound according to any one of [1] to

[13] , wherein the (n+1) R in the formula (1) 3 Each independently represents any one perfluoropolyether chain selected from the group consisting of perfluoropolyether chains represented by the following formulae (5-1) to (5-4).

[0059] -CF2-(OCF2CF2) h -(OCF2) i -OCF2-(5-1)

[0060] (In formula (5-1), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0061] -CF2CF2-(OCF2CF2CF2) j -OCF2CF2-(5-2)

[0062] (In formula (5-2), j represents an average degree of polymerization and is 1 to 15.)

[0063] -CF2CF2CF2-(OCF2CF2CF2CF2) k -OCF2CF2CF2-(5-3)

[0064] (In formula (5-3), k represents an average degree of polymerization and is 1 to 10.)

[0065] -(CF2) w7 -O-(CF2CF2CF2O) w8 -(CF2CF2O) w9 -(CF2) w10 -(5-4)

[0066] (In formula (5-4), w8 and w9 represent average polymerization degrees and are each independently 1 to 20. w7 and w10 represent average values ​​of the number of CF2 groups and are each independently 1 to 2.)

[0067]

[15] The fluorinated ether compound according to any one of [1] to

[14] , which has a number average molecular weight in the range of 500 to 10,000.

[0068]

[16] A lubricant for a magnetic recording medium, comprising the fluorine-containing ether compound according to any one of [1] to

[15] .

[0069]

[17] A magnetic recording medium, characterized in that at least a magnetic layer, a protective layer and a lubricating layer are provided in sequence on a substrate,

[0070] The lubricating layer contains the fluorine-containing ether compound according to any one of [1] to

[15] .

[0071]

[18] The magnetic recording medium according to

[17] , wherein the average film thickness of the lubricating layer is 0.5 nm to 2.0 nm.

[0072] Effects of the Invention

[0073] The fluorine-containing ether compound of the present invention is a compound represented by the above formula (1), and is suitable as a material for a lubricant for magnetic recording media.

[0074] The lubricant for a magnetic recording medium of the present invention contains the fluorine-containing ether compound of the present invention, and therefore can form a lubricating layer which has excellent chemical resistance and suppresses adhesion even if the thickness is thin.

[0075] The magnetic recording medium of the present invention is provided with a lubricating layer that has excellent chemical resistance and suppresses adhesion, and therefore has excellent reliability and durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] [ Figure 1 ] is a schematic cross-sectional view showing one embodiment of the magnetic recording medium of the present invention. DETAILED DESCRIPTION

[0077] The fluorine-containing ether compound, the lubricant for a magnetic recording medium (hereinafter, sometimes simply referred to as "lubricant"), and the magnetic recording medium of the present invention are described in detail below. It should be noted that the present invention is not limited to the embodiments described below.

[0078] Here, the reason why a lubricating layer having excellent chemical resistance and suppressed adhesion can be formed even with a thin thickness when a lubricating layer is formed on a protective layer of a magnetic recording medium using a lubricant containing a fluorinated ether compound according to the present embodiment.

[0079] As shown in formula (1), the fluorine-containing ether compound of this embodiment has R 3When a lubricant containing a fluorinated ether compound is applied to the protective layer to form a lubricating layer, the PFPE chain covers the surface of the protective layer and imparts lubricity to the lubricating layer, thereby reducing the friction between the magnetic head and the protective layer.

[0080] As shown in formula (1), in the case of 3 The backbone of the PFPE chain (-CH2-R 3 [-CH2-R 4 -CH2-R 3 ] n -CH2-) at both ends, through R which is a divalent linking group having one or more polar groups 2 and R 5 And bond R 1 and R 6 Represents the terminal group. 1 and R 6 At least one of the condensed aromatic groups is a benzene ring and a heterocyclic ring containing an amide or ester having high polarity, which are conjugated and fused. In the case where the condensed aromatic group represented by formula (2) contains an amide, the condensed aromatic group has a sp 2 The broad planar structure from the benzene ring to the amide is composed of carbon, oxygen and nitrogen of the hybrid orbital. In addition, when the fused aromatic group represented by formula (2) includes an ester, it has a sp 2 A broad planar structure consisting of carbon and oxygen of a hybrid orbital, from a benzene ring to an ester. The broad planar structure possessed by the condensed ring aromatic group represented by formula (2) can be closely fitted with the protective layer in a plane. It is inferred that the lubricant comprising the fluorinated ether compound represented by formula (1) shows an extremely strong interaction with the protective layer, and even if the coating amount is reduced and the thickness is thinned, the surface of the protective layer can be coated with a high coverage, and a lubricating layer with excellent chemical resistance can be formed. Therefore, the lubricant comprising the fluorinated ether compound of the present embodiment can contribute to the thin filmization of the lubricating layer (reduction of magnetic spacing).

[0081] Furthermore, the condensed aromatic group represented by formula (2) is relatively rigid and therefore difficult to rotate freely. 2 and R 5 The polar groups have difficulty in interacting with each other, and their ability to hinder the interaction between each other and the protective layer is extremely small. Therefore, in the fluorinated ether compound represented by formula (1), the condensed aromatic group represented by formula (2) and R 2 and R 5The polar groups of the formula (1) each independently show good interaction with the protective layer, and can each independently bond with a large number of functional groups (active sites) present on the protective layer. It can be inferred that the lubricating layer containing the fluorinated ether compound represented by formula (1) has excellent adhesion to the protective layer, and can prevent the fluorinated ether compound that does not adhere to the protective layer from agglomerating and adhering to the magnetic head as a foreign matter (stain), thereby suppressing adhesion.

[0082] From the above, it is inferred that the lubricant containing the fluorine-containing ether compound of the present embodiment can form a lubricating layer which can cover the surface of the protective layer firmly and at a high coverage rate even if the lubricating layer is thin, has excellent chemical resistance, and suppresses adhesion.

[0083] The inventors of the present application have confirmed that a lubricating layer having excellent chemical resistance and suppressed adhesion can be formed by using a lubricant containing the above-mentioned fluorinated ether compound, and have thus conceived the present invention.

[0084] The fluorine-containing ether compound, the lubricant for a magnetic recording medium, and the magnetic recording medium of the present invention are described in detail below. It should be noted that the present invention is not limited to the embodiments described below.

[0085] [Fluorinated ether compounds]

[0086] The fluorine-containing ether compound of the present embodiment is represented by the following formula (1).

[0087] R 1 -R 2 -CH2-R 3 [-CH2-R 4 -CH2-R 3 ] n -CH2-R 5 -R 6 (1)

[0088] (In formula (1), n ​​is an integer from 0 to 2. 3 is a perfluoropolyether chain. (n+1) R 3 They may be partially or completely the same, or they may be different. 4 is a divalent linking group having one or more polar groups. When n is 2, the two R 4 Can be the same or different. 2 and R 5 is a divalent linking group having one or more polar groups. 2 With R 5 Can be the same or different. 2 In the R 1 The bonded end has an oxygen atom. 5 In the R6 The bonded end has an oxygen atom. 1 and R 6 For R 2 or R 5 The oxygen atom possessed is bonded to an organic group having 1 to 50 carbon atoms or a hydrogen atom. 1 With R 6 Can be the same or different. 1 and R 6 At least one of them is a structure represented by the following formula (2).

[0089]

[0090] In formula (2), one of X and Y is a carbonyl group (C=O), and the other is -NH-, -NR 7 -(R 7 represents a hydrocarbon group having 1 to 8 carbon atoms. ) or -O-. Q represents that the carbon atoms contained in the connecting group represented by the arc of the dotted line form a heterocyclic structure of a 5- to 8-membered ring together with X and Y. Z represents 0 to 5 substituents. Z is each independently an organic group having 1 to 8 carbon atoms. Z can be bonded to any carbon atom constituting the two rings in formula (2) (excluding the carbonyl carbon atom of X or Y). When there are more than 2 Zs, the two Zs can be bonded to each other to form a ring structure. Any one of the carbon atoms constituting the two rings in formula (2) (excluding the carbonyl carbon atom of X or Y) is bonded to R 2 or R 5 The oxygen atom at the end of the

[0091] The fluorine-containing ether compound of this embodiment is represented by the formula (1), wherein R 3 The backbone of the PFPE chain (-CH2-R 3 [-CH2-R 4 -CH2-R 3 ] n -CH2-) are bonded to both sides with R 2 and R 5 A divalent linking group having one or more polar groups represented by R 1 and R 6 The terminal groups represented by the formula (1) are: 4 -CH2-R 3 ] is 0 to 2. If n is 1 or 2, it becomes R containing a polar group 4The fluorinated ether compound is preferably a fluorinated ether compound. Therefore, when a lubricating layer is formed on a protective layer using a lubricant containing the fluorinated ether compound, a suitable interaction occurs between the lubricating layer and the protective layer, and a lubricating layer that further suppresses adhesion can be formed. In addition, since n is 2 or less, polar groups that do not participate in the interaction with the protective layer are less likely to be generated compared to when n is 3 or more. Therefore, the introduction of pollutants caused by polar groups that do not participate in the interaction is less likely to occur, and a lubricating layer with good resistance to chemical substances can be formed. n can be appropriately determined according to the purpose of the fluorinated ether compound, etc.

[0092] (R 2 and R 5 (represented by the connecting group)

[0093] R 2 and R 5 is a divalent linking group having one or more polar groups. 2 In the R 1 The bonded end has an oxygen atom and R 1 In the case of an organic group, R 2 Through ether bond with R 1 Bonding. 5 In the R 6 The bonded end has an oxygen atom and R 6 In the case of an organic group, R 5 Through ether bond with R 6 In the fluorine-containing ether compound represented by formula (1), R 2 and R 5 Since it has a polar group, when a lubricating layer is formed on the protective layer using a lubricant containing the polar group, a suitable interaction occurs between the lubricating layer and the protective layer. 2 and R 5 It can be appropriately selected depending on the performance required of the lubricant containing the fluorine-containing ether compound.

[0094] As R 2 and R 5 Examples of the polar groups include hydroxyl (-OH), amino (-NH2), carboxyl (-COOH), formyl (-(C=O)H), carbonyl (-CO-), sulfone (-SO3H), etc. 2 and R 5 The number of polar groups contained in each is preferably 1 to 3, more preferably 1 or 2. 2 and / or R 5 When there are two or more polar groups, the types of the polar groups may be partially or entirely the same or different.

[0095] R 2and R 5 Each preferably contains a hydroxyl group as a polar group, and more preferably R 2 and R 5 The polar groups possessed are all hydroxyl groups. The hydroxyl groups interact strongly with the protective layer, especially the protective layer formed by the carbon-based material. 2 and / or R 5 When a hydroxyl group is included as a polar group, the adhesion between the lubricating layer including the fluorine-containing ether compound and the protective layer becomes high.

[0096] In R 2 and R 5 When each contains a hydroxyl group as a polar group, R in formula (1) 2 The hydroxyl groups contained in R 5 The total number of hydroxyl groups contained in is preferably 2 to 6, and more preferably 2 to 4. When the total number of hydroxyl groups is 2 or more, R can be obtained more effectively. 2 and R 5 The interaction between the hydroxyl groups and the protective layer. As a result, the fluorinated ether compound can form a lubricating layer with higher adhesion to the protective layer. In addition, if the total number of the hydroxyl groups is 6 or less, the hydroxyl groups that do not participate in the bonding between the lubricating layer and the active sites on the protective layer can be prevented from attracting environmental substances that generate pollutants to the lubricating layer, thereby suppressing contamination caused by chemical substances.

[0097] R 2 The divalent linking group represented by 1 The end bonded to R has an oxygen atom, and the other end (bonded to R 2 The end of the adjacent methylene group (-CH2-) is also provided with an oxygen atom. 5 The divalent linking group represented by 6 The end bonded to R has an oxygen atom, and the other end (bonded to R 5 Oxygen atoms are also arranged at the ends of adjacent methylene groups. 2 and R 5 The oxygen atom at the end of the divalent linking group represented by R 2 and R 5 The adjacent methylene groups form an ether bond (—O—). The ether bond imparts appropriate flexibility to the fluorine-containing ether compound represented by the formula (1), and increases the affinity of the polar group possessed by the linking group with the protective layer.

[0098] R 2 and R 5The divalent linking group represented by is preferably an alkylene group having 3 to 9 carbon atoms and having oxygen atoms at both ends and 1 or 2 hydrogen atoms substituted by hydroxyl groups, and the alkylene group has more preferably 3 to 5 carbon atoms. The alkylene group may contain an ether bond between carbon atoms.

[0099] Specifically, R 2 and R 5 Each of them is independently preferably a linking group represented by the following formula (3). 2 and R 5 is a linking group represented by the following formula (3), then R 1 -R 2 -and-R 5 -R 6 It becomes softer and the interaction with the protective layer is further improved.

[0100]

[0101] (In formula (3), p represents an integer of 1 to 3. q represents an integer of 1 to 5. r represents an integer of 1 to 5. When p is 2 or more, the combination of q and r in each structural unit may be the same or different. In formula (3), the oxygen atom at the left terminal and the oxygen atom arranged in R in formula (1) 2 or R 5 R 1 In formula (3), the oxygen atom at the right terminal is bonded to the group arranged at R in formula (1). 2 or R 5 R 6 The side groups are bonded.)

[0102] In the linking group represented by formula (3), p is an integer of 1 to 3. Since p is 1 or more, R 2 or R 5 The connecting group represented by has one or more hydroxyl groups, and becomes a fluorine-containing ether compound that can obtain a lubricating layer with good adhesion to the protective layer. In addition, since p is 3 or less, it is possible to prevent the R 2 or R 5 The large number of hydroxyl groups in the connecting group represented by α-β ...

[0103] In the linking group represented by formula (3), p is preferably 1 or 2. If p is 1 or 2, then R 2 or R 5 The number of hydroxyl groups in the connecting group represented by is appropriate, and the introduction of contaminants due to hydroxyl groups that are not involved in bonding with active sites on the protective layer is less likely to occur, thereby enabling the formation of a lubricating layer with better chemical resistance.

[0104] In the linking group represented by formula (3), q and r are each an integer of 1 to 5. Since q and r are integers of 1 to 5, the number of carbon atoms in the molecule does not become excessive due to the methylene group contained in formula (3). Therefore, in the fluorine-containing ether compound represented by formula (1), the proportion of fluorine atoms in the entire molecule tends to become appropriate, and a lubricating layer with excellent lubricity can be formed. q and r are each preferably 1 to 4.

[0105] When p in formula (3) is 2 or more, each structural unit (-(CH2) q -CH(OH)-(CH2) r The combination of q and r in (a) may be the same or different. In each structural unit, at least one of q and r is preferably 1.

[0106] R 2 More preferably, it is a linking group represented by the following formula (3-1) or (3-2).

[0107]

[0108] (p1 in formula (3-1) represents an integer of 1 to 3. q1 in formula (3-2) represents an integer of 2 to 4. In formulas (3-1) and (3-2), the oxygen atom at the left terminal and R in formula (1) 1 Bonding. )

[0109] R in formula (1) 5 More preferably, it is a linking group represented by the following formula (3-3) or (3-4).

[0110]

[0111] (p2 in formula (3-3) represents an integer of 1 to 3. r2 in formula (3-4) represents an integer of 2 to 4. In formulas (3-3) and (3-4), the oxygen atom at the right terminal and R in formula (1) 6 Bonding. )

[0112] The linking groups represented by formulas (3-1) to (3-4) are linking groups having hydroxyl groups that have a strong interaction with the protective layer, among polar groups. In addition, in the linking groups represented by formulas (3-1) to (3-4), methylene groups are arranged on both sides of the carbon atom to which the hydroxyl group is bonded. 2 In the case of a linking group represented by formula (3-1) or (3-2), and in the case of R 5 In the case of a linking group represented by formula (3-3) or (3-4), due to the following reasons <1> , <2> This is a fluorine-containing ether compound that can provide a lubricating layer having higher adhesion to the protective layer.

[0113] <1> The carbon atom to which the hydroxyl group contained in the linking group represented by formula (3-1) to (3-4) is bonded and R 1 or R 6 Between them, at least a methylene group and R 2 or R 5 Therefore, the hydroxyl group contained in the linking group represented by formula (3-1) to (3-4) and R 1 and / or R 6 The distance between the terminal groups represented by becomes appropriate. 1 With R 2 and R 5 With R 6 The oxygen atom in the connecting part of R can slightly inhibit the free rotation of the terminal group. 1 and / or R 6 The terminal group represented by and the hydroxyl group of the linking group represented by formula (3-1) to (3-4) are unlikely to interact with each other. 1 and / or R 6 The terminal groups shown each independently show good interaction with the protective layer and each independently tend to bond to a functional group (active site) present in large quantities on the protective layer.

[0114] <2> In R 2 In the case of a linking group represented by formula (3-1) or (3-2), R 2 and R 1 Bonded via oxygen atoms, and R 2 and R 2 Adjacent methylene groups are bonded via oxygen atoms. 5 In the case of a linking group represented by formula (3-3) or (3-4), R 5 and R 6 Bonded via oxygen atoms, and R 5 and R 5 Adjacent methylene groups are bonded via oxygen atoms. As a result, a fluorine-containing ether compound having moderate flexibility can be obtained, and a lubricating layer having better chemical resistance can be formed.

[0115] In the linking groups represented by formulae (3-1) and (3-3), p1 and p2 are each an integer of 1 to 3. Since p1 and p2 are 1 or more, a fluorine-containing ether compound can be obtained that can provide a lubricating layer having good adhesion to the protective layer. In addition, since p1 and p2 are 3 or less, it is possible to prevent the polarity of the fluorine-containing ether compound from becoming too high due to the large number of hydroxyl groups in the linking groups represented by formulae (3-1) and (3-3), thereby preventing contamination caused by chemical substances.

[0116] In the linking groups represented by formulae (3-1) and (3-3), when p1 and p2 are each 2 or 3, the distance between the hydroxyl groups contained in the linking groups represented by formulae (3-1) and (3-3) becomes appropriate. As a result, even if R 2 or R 5 The number of hydroxyl groups contained in is multiple, R 2 or R 5 The hydroxyl groups contained therein are also easily involved in the bonding with the active sites on the protective layer. In the connecting groups represented by formulas (3-1) and (3-3), p1 and p2 are preferably 1 or 2. When p1 and p2 are 1, it becomes a fluorine-containing ether compound that is easy to synthesize, which is more preferred.

[0117] In the linking groups represented by formulae (3-2) and (3-4), q1 and r2 are each an integer of 2 to 4. Since q1 and r2 are integers of 2 to 4, the affinity for pollutants is reduced by the methylene groups contained in formulae (3-2) and (3-4), and a fluorinated ether compound having high chemical resistance can be obtained.

[0118] In formula (1), it is further preferred that R 2 is a linking group represented by formula (3-1) or (3-2), and R 5 It is a connecting group represented by formula (3-3) or (3-4).

[0119] In the fluorinated ether compound represented by formula (1), R 2 With R 5 can be the same or different. It should be noted that the so-called "R 2 With R 5 Same” means R 2 The atoms contained in R 5 The atoms contained in -CH2-R 3 [-CH2-R 4 -CH2-R 3 ] n -CH2- and symmetrically arranged. That is, it is preferred that "R 2 Formula (3-1), R 5 is formula (3-3), p1 in formula (3-1) is the same as p2 in formula (3-3)" or "R 2 Formula (3-2), R 5 In formula (3-4), q1 in formula (3-2) is the same as r2 in formula (3-4).

[0120] (R 4 (represented by a divalent connecting group)

[0121] In the fluorine-containing ether compound represented by formula (1), when n is 1 or 2, R 4 It is configured in R 3 A divalent linking group having one or more polar groups between PFPE chains represented by R 4 The polar group contained in the formula (1) allows the fluorine-containing ether compound to adhere closely to the protective layer. Therefore, a thin lubricating layer can be formed with a sufficient coverage by using a lubricant containing the fluorine-containing ether compound represented by the formula (1).

[0122] As R 4 The polar groups contained in R include, for example, hydroxyl (-OH), amino (-NH2), carboxyl (-COOH), formyl (-(C=O)H), carbonyl (-CO-), sulfone (-SO3H), etc. 4 The number of polar groups contained in is preferably 1 to 3, more preferably 1 or 2. 4 When there are two or more polar groups, the types of the polar groups may be partially or entirely the same or different.

[0123] R 4 Preferably, it contains hydroxyl groups as polar groups, preferably R 4 All polar groups contained in are hydroxyl groups. The interaction between hydroxyl groups and the protective layer, especially the protective layer formed by carbon-based materials, is large. Therefore, if R 4 When a hydroxyl group is included as a polar group, the adhesion between the lubricating layer including the fluorine-containing ether compound and the protective layer becomes high.

[0124] R 4 Preferably, oxygen atoms are arranged at both ends. The oxygen atoms arranged at both ends of the linking group form ether bonds (-O-) with the methylene groups (-CH2-) arranged on both sides thereof. These two ether bonds impart appropriate flexibility to the fluorinated ether compound represented by formula (1), thereby increasing the affinity between the polar group possessed by the linking group and the protective layer.

[0125] R 4 It is preferably an alkylene group having 3 to 6 carbon atoms and oxygen atoms at both ends and 1 or 2 hydrogen atoms substituted with hydroxyl groups, and the alkylene group has more preferably 3 to 4 carbon atoms. The alkylene group may contain an ether bond between carbon atoms.

[0126] Specifically, n R 4 Each of them is independently preferably a linking group represented by the following formula (4). This is because if R 4 When the linking group is represented by the following formula (4), the structure between PFPE chains becomes flexible, and the interaction with the protective layer is further enhanced.

[0127]

[0128] (In formula (4), s represents an integer of 1 to 3. t represents an integer of 1 to 5. u represents an integer of 1 to 5. When s is 2 or more, the combination of t and u in each structural unit may be the same or different. In formula (4), the oxygen atom at the left terminal and the oxygen atom arranged in R in formula (1) 4 R 1 In formula (4), the oxygen atom at the right terminal is bonded to the group arranged at R in formula (1). 4 R 6 The side groups are bonded.)

[0129] In the linking group represented by formula (4), s is an integer of 1 to 3. Since s is 1 or more, R 4 The connecting group represented by has one or more hydroxyl groups, and becomes a fluorine-containing ether compound that can obtain a lubricating layer with good adhesion to the protective layer. In addition, since s is 3 or less, it is possible to prevent the R 4 The large number of hydroxyl groups in the connecting group represented by α-β ...

[0130] In the linking group represented by formula (4), s is preferably 1 or 2. If s is 1 or 2, then R 4 The number of hydroxyl groups in the connecting group represented by is appropriate, and the introduction of contaminants due to hydroxyl groups that are not involved in bonding with active sites on the protective layer is less likely to occur, thereby enabling the formation of a lubricating layer with better chemical resistance.

[0131] In the linking group represented by formula (4), t and u are each an integer of 1 to 5. Since t and u are integers of 1 to 5, the number of carbon atoms in the molecule does not become excessive due to the methylene group contained in formula (4). Therefore, in the fluorine-containing ether compound represented by formula (1), the proportion of fluorine atoms in the entire molecule tends to become appropriate, and a lubricating layer with excellent lubricity can be formed. t and u are each preferably 1 to 4.

[0132] When s in formula (4) is 2 or more, each structural unit (-(CH2) t -CH(OH)-(CH2) u The combination of t and u in (a)-(-O-) may be the same or different. In each structural unit, at least one of t and u is preferably 1.

[0133] n R 4 Each independently is more preferably any one of the following formulas (4-1) to (4-3). 4 Any of the formulae (4-1) to (4-3) is preferred because the fluorine-containing ether compound containing the same can be easily synthesized.

[0134]

[0135] (In formula (4-1), s1 represents an integer from 1 to 3.)

[0136] (t1 in formula (4-2) represents an integer of 2 to 4. In formula (4-2), the oxygen atom at the left terminal is bonded to R in formula (1). 4 R 1 methylene groups adjacent to the side.)

[0137] (u1 in formula (4-3) represents an integer of 2 to 4. In formula (4-3), the oxygen atom at the right terminal is bonded to R 4 R 6 methylene groups adjacent to the side.)

[0138] In the linking group represented by formula (4-1), s1 is an integer of 1 to 3. Since s1 is 1 or more, a lubricating layer having good adhesion to the protective layer can be obtained as a fluorine-containing ether compound. In addition, since s1 is 3 or less, it is possible to prevent the R 4 If there are too many hydroxyl groups in the connecting group represented by , the polarity of the fluorine-containing ether compound becomes too high, and contamination by chemical substances occurs.

[0139] In the linking group represented by formula (4-1), when s1 in formula (4-1) is 2 or 3, the distance between the hydroxyl groups contained in the linking group represented by formula (4-1) becomes appropriate. As a result, even if R 4 The number of hydroxyl groups contained in is multiple, R 4 The hydroxyl groups contained in the protective layer are also easily involved in the bonding with the active sites on the protective layer. s1 is preferably 1 or 2.

[0140] In the linking groups represented by formulae (4-2) and (4-3), t1 and u1 are each an integer of 2 to 4. Since t1 and u1 are integers of 2 to 4, the affinity for pollutants is reduced by the methylene groups contained in formulae (4-2) and (4-3), and a fluorinated ether compound having high chemical resistance can be obtained.

[0141] When n is 2, the two R in formula (1) 4 They can be the same or different. It should be noted that the so-called "2 R 4 Same” means R 1 Side R 4 The atoms contained in R 6 Side R 4 The atoms contained in the molecule are relative to the R 3 That is, it is preferred that "two R 4is formula (4-1), s1 in formula (4-1) is the same" or "two R 2 One of them is formula (4-2), and the other is formula (4-3), and t1 in formula (4-2) is the same as u1 in formula (4-3).

[0142] Preferably, R in formula (1) 2 , R 4 and R 5 The polar groups in are all hydroxyl groups. When n is 0, the polar groups are R 2 and R 5 This is because if R 2 , R 4 and R 5 If all the polar groups in the protective layer are hydroxyl groups, the coating state of the protective layer becomes uniform.

[0143] In formula (1), R 2 , R 4 and R 5 When part or all of the polar groups in are hydroxyl groups, R 2 The hydroxyl groups, R 4 The hydroxyl groups contained in R 5 The total number of hydroxyl groups contained in is preferably 2 to 8, more preferably 2 to 6. When n is 0, the total number refers to R 2 The hydroxyl groups contained in R 5 If the total number of the above-mentioned hydroxyl groups is 2 or more, R can be obtained more effectively. 2 and R 5 The interaction between the hydroxyl groups and the protective layer. As a result, the fluorinated ether compound can form a lubricating layer with higher adhesion to the protective layer. In addition, if the total number of the hydroxyl groups is 8 or less, the hydroxyl groups that do not participate in the bonding between the lubricating layer and the active sites on the protective layer can be prevented from attracting environmental substances that generate pollutants to the lubricating layer, thereby suppressing contamination caused by chemical substances.

[0144] Preferred R 2 , R 4 and R 5 At least one of the hydroxyl groups has a glycerol structure (-OCH2CH(OH)CH2O-). The glycerol structure is soft, so the hydroxyl groups can move independently, making the interaction between the hydroxyl groups and the protective layer stronger. Thus, a lubricating layer that further suppresses adhesion can be formed.

[0145] (R 3 PFPE chain represented by

[0146] In the fluorine-containing ether compound represented by the general formula (1), R 3When a lubricant containing a fluorinated ether compound according to the present embodiment is applied onto the protective layer to form a lubricating layer, R 3 The PFPE chains represented by R cover the surface of the protective layer and impart lubricity to the lubricating layer, thereby reducing the friction between the magnetic head and the protective layer. 3 The PFPE chain represented can be appropriately selected depending on the performance required of the lubricant containing the fluorine-containing ether compound, etc.

[0147] (n+1) R 3 The R may be partially or completely the same, or may be different. 3 This is because the coating state of the protective layer with the fluorinated ether compound becomes more uniform, resulting in a lubricating layer with better adhesion. 3 More than 2 R 3 The same means (n+1) R 3 The same structure R containing two or more repeating units of PFPE chains 3 The same R 3 The same repeating unit structure but different average polymerization degrees are also included in R 3 .

[0148] As R 3 The PFPE chain represented by may be a chain composed of a polymer or copolymer of perfluoroalkylene oxide, etc. Examples of the perfluoroalkylene oxide include perfluoromethylene oxide, perfluoroethylene oxide, perfluoropropylene oxide, perfluoroisopropylene oxide, and perfluorobutylene oxide.

[0149] The (n+1) R in formula (1) 3 Each independently preferably is a PFPE chain represented by the following formula (5) derived from a polymer or copolymer of a perfluoroalkylene oxide, for example.

[0150] -(CF2) w1 -O-(CF2O) w2 -(CF2CF2O) w3 -(CF2CF2CF2O) w4 -(CF2CF2CF2CF2O) w5 -(CF2) w6 -(5)

[0151] (In formula (5), w2, w3, w4, and w5 represent average polymerization degrees, and each independently represents 0 to 20. However, the case where w2, w3, w4, and w5 are all 0 at the same time is excluded. w1 and w6 represent the average value of the number of CF2, and each independently represents 1 to 3. The arrangement order of the repeating units (CF2O), (CF2CF2O), (CF2CF2CF2O), and (CF2CF2CF2CF2O) in formula (5) is not particularly limited.)

[0152] In formula (5), w2, w3, w4, and w5 represent average polymerization degrees, and each independently represents 0 to 20, preferably 0 to 15, and more preferably 0 to 10.

[0153] In formula (5), w1 and w6 are average values ​​representing the number of CF2, and each independently represents 1 to 3. w1 and w6 can be determined based on the structure of the repeating unit arranged at the end of the chain structure in the PFPE chain represented by formula (5).

[0154] In formula (5), (CF2O), (CF2CF2CF2O), (CF2CF2CF2O), (CF2CF2CF2CF2O) are repeating units. The arrangement order of the repeating units in formula (5) is not particularly limited. In addition, the number of types of repeating units in formula (5) is not particularly limited.

[0155] The (n+1) R in formula (1) 3 Each independently is preferably any one PFPE chain selected from the PFPE chains represented by the following formulae (5-1) to (5-4).

[0156] If (n+1) R 3 Each of the (n+1) R 3 When each is any one of the PFPE chains represented by formulas (5-1) to (5-4), the ratio of the number of oxygen atoms in the PFPE chain to the number of carbon atoms (the number of ether bonds (-O-)) is appropriate. Therefore, it becomes a fluorine-containing ether compound with moderate hardness. Therefore, the fluorine-containing ether compound applied to the protective layer is not easy to agglomerate on the protective layer, and a thinner lubricating layer can be formed with sufficient coverage. In addition, if (n+1) R 3 When each of them is any one selected from the PFPE chains represented by formulae (5-1) to (5-4), they have appropriate flexibility and thus become fluorine-containing ether compounds capable of forming a lubricating layer having better chemical resistance.

[0157] -CF2-(OCF2CF2) h-(OCF2) i -OCF2-(5-1)

[0158] (In formula (5-1), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0159] -CF2CF2-(OCF2CF2CF2) j -OCF2CF2-(5-2)

[0160] (In formula (5-2), j represents an average degree of polymerization and is 1 to 15.)

[0161] -CF2CF2CF2-(OCF2CF2CF2CF2) k -OCF2CF2CF2-(5-3)

[0162] (In formula (5-3), k represents an average degree of polymerization and is 1 to 10.)

[0163] -(CF2) w7 -O-(CF2CF2CF2O) w8 -(CF2CF2O) w9 -(CF2) w10 -(5-4)

[0164] (In formula (5-4), w8 and w9 represent average polymerization degrees and are each independently 1 to 20. w7 and w10 represent average values ​​of the number of CF2 groups and are each independently 1 to 2.)

[0165] In formula (5-1), the arrangement order of repeating units (OCF2CF2) and (OCF2) is not particularly limited. In formula (5-1), the number h of (OCF2CF2) and the number i of (OCF2) may be the same or different. The PFPE chain represented by formula (5-1) may also be a polymer of (OCF2CF2). In addition, the PFPE chain represented by formula (5-1) may be any random copolymer, block copolymer, or alternating copolymer composed of (OCF2CF2) and (OCF2).

[0166] In formulas (5-1) to (5-3), h, which represents the average degree of polymerization, is 1 to 20, i is 0 to 20, j is 1 to 15, and k is 1 to 10, so that a fluorinated ether compound can obtain a lubricating layer having good lubricity. In addition, in formulas (5-1) to (5-3), h and i, which represent the average degree of polymerization, are 20 or less, j is 15 or less, and k is 10 or less, so that the viscosity of the fluorinated ether compound does not become too high, and the lubricant containing it becomes easy to apply, and thus it is preferred. In order to obtain a fluorinated ether compound that is easy to infiltrate and spread on the protective layer and to easily obtain a lubricating layer having a uniform film thickness, h, i, j, and k, which represent the average degree of polymerization, are preferably 1 to 10, more preferably 1.5 to 8, and even more preferably 2 to 7.

[0167] In formula (5-4), the arrangement order of repeating units (CF2CF2CF2O) and (CF2CF2O) is not particularly limited. In formula (5-4), the number w8 of (CF2CF2CF2O) and the number w9 of (CF2CF2O) may be the same or different. Formula (5-4) may include any copolymer of random copolymer, block copolymer, and alternating copolymer composed of monomer units (CF2CF2CF2O) and (CF2CF2O).

[0168] In formula (5-4), w8 and w9 representing the average degree of polymerization are each independently 1-20, preferably 1-15, and more preferably 1-10.

[0169] w7 and w10 in formula (5-4) are average values ​​representing the number of CF2, and each independently represents 1 to 2. w7 and w10 can be determined based on the structure of the repeating unit arranged at the end of the chain structure in the PFPE chain represented by formula (5-4).

[0170] (R 1 and R 6 The terminal group represented by

[0171] In the fluorine-containing ether compound represented by formula (1), R 1 and R 6 For R 2 or R 5 The oxygen atom possessed is bonded to an organic group having 1 to 50 carbon atoms or a hydrogen atom. 1 and R 6 At least one of the terminal groups represented by is a structure represented by the above formula (2) (hereinafter, sometimes referred to as a "condensed ring aromatic group").

[0172] In the fluorinated ether compound represented by formula (1), the condensed aromatic group represented by formula (2) exhibits a moderate interaction with the protective layer. Therefore, the condensed aromatic group represented by formula (2) has the function of improving the adhesion between the lubricating layer and the protective layer, forming a lubricating layer having good chemical resistance and suppressed adhesion.

[0173] In formula (2), Q represents a carbon atom contained in the linking group represented by the arc of the dotted line, which forms a 5- to 8-membered heterocyclic structure together with X and Y. The heterocyclic structure preferably has 6 ring members.

[0174] In formula (2), one of X and Y is a carbonyl group (C=O), and the other is -NH-, -NR 7 -(R 7 represents a hydrocarbon group having 1 to 8 carbon atoms. ) or -O-. Therefore, -XY- is an amide or an ester. One of X and Y is -NR 7 -In the case of R 7 , examples of R include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, and alkyl groups substituted with aryl groups, etc., having 1 to 8 carbon atoms. 7 , specifically, methyl, ethyl, propyl, butyl, allyl, butenyl, propargyl, phenyl, benzyl, etc. are preferred.

[0175] The carbon atoms constituting the two rings in formula (2) (excluding the carbonyl carbon atom of X or Y) may have Z as a substituent. The number of Z is 0 to 5, preferably 0 to 3, and more preferably 0 to 2. When formula (2) has two or more Zs, the types of Zs may be partially or completely the same, or may be different.

[0176] Z is independently an organic group having 1 to 8 carbon atoms. The organic group is preferably selected from alkyl, alkenyl, alkynyl, aryl, alkyl substituted with aryl, and alkoxy groups having 1 to 8 carbon atoms. Specifically, it is more preferably any of phenyl, methyl, methoxy, allyl, butenyl, propargyl, and benzyl. If the organic group is any of these groups, R as a terminal group can be more effectively suppressed. 1 and / or R 6 , and the adjacent R as a linking group 2 and / or R 5 The interaction between the polar groups possessed by the fluorine-containing ether compound makes the compound have a high affinity with the protective layer.

[0177] When there are two or more Zs, the two Zs may be bonded to each other to form a ring structure. In this case, the two Zs are preferably bonded to the carbon atoms that do not bond to R in the two rings. 2 or R 5The ring structure is preferably a 5-membered ring or a 6-membered ring, more preferably a 6-membered ring. The ring structure can be composed of only carbon atoms or can contain heteroatoms (e.g., -O-, -NH-). In the case where two Zs are bonded to each other to form a ring structure, the ring structure is preferably a benzene ring.

[0178] In formula (2), any one of the carbon atoms constituting the two rings (excluding the carbonyl carbon atom of X or Y) is bonded to R 2 or R 5 That is, in the two rings, the carbon atom constituting the benzene ring and R 2 or R 5 The carbon atom constituting the heterocyclic structure represented by Q and R 2 or R 5 The carbon atom contained in Z is not included in the carbon atoms constituting the two rings.

[0179] The condensed ring aromatic group represented by the formula (2) is preferably a structure represented by the following formula (2-1).

[0180]

[0181] (In formula (2-1), one of X and Y is a carbonyl group (C=O), and the other is -NH-, -NR 7 -(R 7 represents a hydrocarbon group having 1 to 8 carbon atoms. ) or -O-. Z is 0 to 5 substituents. Z is each independently an organic group having 1 to 8 carbon atoms. Z may be bonded to any carbon atom constituting the two rings in formula (2-1) (excluding the carbonyl carbon atom of X or Y). When there are 2 or more Zs, the two Zs may be bonded to each other to form a ring structure. Any one of the carbon atoms constituting the two rings in formula (2-1) (excluding the carbonyl carbon atom of X or Y) is bonded to R 2 or R 5 The oxygen atom at the end of the

[0182] Formula (2-1) represents a structure in which Q in formula (2) is a 6-membered heterocyclic ring and X is located at an ortho position to a carbon atom shared by the heterocyclic ring and the benzene ring. 1 and R 6 It is preferred that at least one of the compounds is the formula (2-1), because the production of the fluorine-containing ether compound becomes easy.

[0183] Specific examples and preferred examples of the structures of X, Y, and Z, the number of Z, and the bonding form of Z in formula (2-1) are the same as those described for formula (2).

[0184] Examples of the condensed aromatic group represented by formula (2-1) include, but are not limited to, any organic group represented by the following formulas (6-1) to (6-11). The dotted lines in formulas (6-1) to (6-11) are the dotted lines in formula (1) that are connected to R. 2 or R 5 Bonded connection keys.

[0185]

[0186] Among the formulae (6-1) to (6-11), the formulae (6-1) to (6-3) are preferably used because they are fluorine-containing ether compounds that are relatively easy to produce.

[0187] In the fluorine-containing ether compound represented by formula (1), R 1 and R 6 When both of the terminal groups represented by are fused aromatic groups represented by formula (2), R 1 With R 6 They can be the same or different. 1 With R 6 If the fluorine-containing ether compound is the same, the fluorine-containing ether compound is easy to produce and is therefore preferred.

[0188] In R 1 and R 6 Among the terminal groups represented by 1 ) is a structure represented by formula (2), the other terminal group (for example, R 6 ) is an organic group having 1 to 50 carbon atoms or a hydrogen atom. When the other terminal group is the above-mentioned organic group, the number of carbon atoms contained in the organic group is preferably 2 to 20, and more preferably 2 to 10. Preferably, the other terminal group is not a structure represented by formula (2), and is an organic group having at least one double bond or triple bond, an alkyl group having 1 to 8 carbon atoms which may have a substituent, or a hydrogen atom.

[0189] When the other terminal group is not a structure represented by formula (2) and is an organic group having at least one double bond or triple bond, examples thereof include a group containing an aromatic ring, a group containing an unsaturated heterocyclic ring, a group containing an alkenyl group, a group containing an alkynyl group, etc. The double bond and triple bond may be a carbon-carbon bond or a bond between a carbon atom and a heteroatom.

[0190] When the other terminal group is an alkyl group having 1 to 8 carbon atoms which may have a substituent, examples of the substituent include alkoxy, hydroxy, mercapto, carboxyl, carbonyl, amino, fluoro, etc. The alkyl group more preferably has 1 to 6 carbon atoms, and further preferably has 1 to 4 carbon atoms.

[0191] The other terminal group is preferably an alkyl group having 1 to 8 carbon atoms and having a hydroxyl group, and the hydroxyl group is more preferably a primary hydroxyl group.

[0192] In the case where the other terminal group is a hydrogen atom, R as a hydrogen atom 6 and configured in R 5 The oxygen atom at the end (or, as a hydrogen atom, R 1 and configured in R 2 The terminal oxygen atom) forms a hydroxyl group.

[0193] When the other terminal group is not a structure represented by formula (2) and is an organic group having at least one double bond or triple bond, specific examples thereof include phenyl, methoxyphenyl, fluorophenyl, naphthyl, phenethyl, methoxyphenethyl, fluorophenethyl, benzyl, methoxybenzyl, naphthylmethyl, methoxynaphthyl, pyrrolyl, pyrazolyl, methylpyrazolylmethyl, imidazolyl, furanyl, furfuryl, oxazolyl, isoxazolyl, thienyl, thienylethyl, thiazolyl, methylthiazolyl. 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl, 1-Butyl,

[0194] When the other terminal group is an alkyl group having 1 to 8 carbon atoms which may have a substituent, specific examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, perfluorohexyl, octafluoropentyl, tridecafluorooctyl, hydroxymethyl (-CH2OH), hydroxyethyl (-CH2CH2OH), hydroxypropyl (-CH2CH2CH2OH), hydroxybutyl (-CH2CH2CH2CH2OH), and the like.

[0195] Among the above, the other terminal group is preferably any of phenyl, methoxyphenyl, naphthyl, phenethyl, methoxyphenethyl, fluorophenethyl, thienylethyl, allyl, butenyl, propargyl, and hydroxyethyl, and particularly preferably any of phenyl, naphthyl, thienylethyl, allyl, butenyl, and hydroxyethyl. In this case, it becomes a fluorine-containing ether compound that can form a lubricating layer having more excellent wear resistance.

[0196] In R 1 and R 6 When both of them are terminal groups represented by formula (2), R 2 and R 5The number of polar groups possessed is preferably 1. In this case, R 2 and R 5 Each of the polar groups can participate in the bonding between the lubricating layer and the active site on the protective layer, and thus better chemical resistance can be obtained.

[0197] In the fluorinated ether compound represented by formula (1), R 3 The (n+1) PFPE chains represented are identical and R 1 -R 2 -With R 6 -R 5 - is the same, since it can be manufactured easily and efficiently, it is preferred. 3 The (n+1) PFPE chains represented are identical and R 1 -R 2 -With R 6 -R 5 -same", when n is 0, it means R 1 -R 2 -With R 6 -R 5 -same, when n is 1 or 2, refers to all R 3 Same and R 1 -R 2 -With R 6 -R 5 -same.

[0198] When n is 1 or 2, and R 4 In the case where n is 1, the fluorinated ether compound is preferably R. 4 As the central symmetric structure, when n is 2, the R 3 Since it is a centrally symmetrical structure, it is easy to evenly infiltrate and spread on the protective layer, and it is easy to obtain a lubricating layer with a uniform film thickness, which is preferred.

[0199] Specifically, the fluorinated ether compound represented by formula (1) is preferably any compound represented by the following formulas (A) to (Z), (AA), and (AB). When the compound represented by formula (1) is any compound represented by the following formulas (A) to (Z), (AA), and (AB), the raw material is easy to obtain, and a lubricating layer having excellent adhesion even with a thin thickness, and better chemical resistance and adhesion suppression effect can be formed, which is preferred.

[0200] The compounds represented by the following formulae (A) to (Z), (AA), and (AB) are all compounds wherein R 3 The (n+1) PFPE chains represented are all the same. In the compounds represented by the following formulae (A) to (Z), (AA), and (AB), Rf1, Rf2, and Rf3 representing the PFPE chains are each the following structures. It should be noted that h, i, j, and k in the formulae (A) to (Z), (AA), and (AB) are values ​​representing the average degree of polymerization and are not necessarily integers.

[0201]

[0202] In the compounds represented by the following formulae (A) to (F), n is 0, R 6 is hydroxyethyl, R 2 is a connecting group represented by the above formula (3-1) and p1 is 1, R 5 is a connecting group represented by the above formula (3-3) and p2 is 1, R 3 It is represented by the above formula (5-1).

[0203] In the compound represented by the following formula (A), R 1 It is an organic group represented by the above formula (6-1).

[0204] In the compound represented by the following formula (B), R 1 It is an organic group represented by the above formula (6-2).

[0205] In the compound represented by the following formula (C), R 1 It is an organic group represented by the above formula (6-3).

[0206] In the compound represented by the following formula (D), R 1 It is an organic group represented by the above formula (6-6).

[0207] In the compound represented by the following formula (E), R 1 It is an organic group represented by the above formula (6-7).

[0208] In the compound represented by the following formula (F), R 1 It is an organic group represented by the above formula (6-10).

[0209] In the compounds represented by formula (G) and (H), n is 0, R 2 is a connecting group represented by formula (3-1) and p1 is 1, R 5 is a connecting group represented by formula (3-3) and p2 is 1, R 3 Expressed by formula (5-1).

[0210] In the compound represented by formula (G), R 1 and R6 It is an organic group represented by formula (6-1).

[0211] In the compound represented by formula (H), R 1 and R 6 It is an organic group represented by formula (6-2).

[0212] In the compounds represented by formula (I) and (J), n is 0, R 2 is a connecting group represented by formula (3-1) and p1 is 1, R 3 Expressed by formula (5-1).

[0213] In the compound represented by formula (I), R 1 is an organic group represented by formula (6-1), R 6 is allyl, R 5 It is a connecting group represented by formula (3-3) and p2 is 2.

[0214] In the compound represented by formula (J), R 1 is an organic group represented by formula (6-2), R 6 is phenyl, R 5 It is a connecting group represented by formula (3-3) and p2 is 1.

[0215] In the compound represented by formula (K), (L), n is 0, R 6 is hydroxyethyl, R 5 is a connecting group represented by formula (3-3) and p2 is 1, R 3 Expressed by formula (5-1).

[0216] In the compound represented by formula (K), R 1 is an organic group represented by formula (6-1), R 2 It is a connecting group represented by formula (3-1) and p1 is 2.

[0217] In the compound represented by formula (L), R 1 is an organic group represented by formula (6-2), R 2 It is a connecting group represented by formula (3-2) and q1 is 2.

[0218] In the compound represented by formula (M), (N), n is 0, R 6 is hydroxyethyl, R 2 is a connecting group represented by formula (3-1) and p1 is 1, R 5 It is a connecting group represented by formula (3-3) and p2 is 1.

[0219] In the compound represented by formula (M), R 1 is an organic group represented by formula (6-1), R 3Expressed by formula (5-2).

[0220] In the compound represented by formula (N), R 1 is an organic group represented by formula (6-2), R 3 Expressed by formula (5-3).

[0221] In the compounds represented by formula (O) and (P), n is 1, R 2 is a connecting group represented by formula (3-1) and p1 is 1, R 5 is a connecting group represented by formula (3-3) and p2 is 1, R 4 is a connecting group represented by formula (4-1) and s1 is 1, R 3 Expressed by formula (5-1).

[0222] In the compound represented by formula (O), R 1 and R 6 It is an organic group represented by formula (6-1).

[0223] In the compound represented by formula (P), R 1 and R 6 It is an organic group represented by formula (6-2).

[0224] In the compounds represented by formula (Q) and (R), n is 1, R 2 is a connecting group represented by formula (3-1) and p1 is 1, R 4 is a connecting group represented by formula (4-1) and s1 is 1, R 3 Expressed by formula (5-1).

[0225] In the compound represented by formula (Q), R 1 is an organic group represented by formula (6-1), R 6 is hydroxyethyl, R 5 It is a connecting group represented by formula (3-3) and p2 is 1.

[0226] In the compound represented by formula (R), R 1 is an organic group represented by formula (6-2), R 6 is allyl, R 5 It is a connecting group represented by formula (3-3) and p2 is 2.

[0227] In the compounds represented by formula (S) and (T), n is 1, R 4 is a connecting group represented by formula (4-1) and s1 is 1, R 3 Expressed by formula (5-1).

[0228] In the compound represented by formula (S), R 1 and R 6is an organic group represented by formula (6-1), R 2 is a connecting group represented by formula (3-1) and p1 is 2, R 5 It is a connecting group represented by formula (3-3) and p2 is 2.

[0229] In the compound represented by formula (T), R 1 and R 6 is an organic group represented by formula (6-2), R 2 is a connecting group represented by formula (3-2) and q1 is 2, R 5 It is a connecting group represented by formula (3-4) and r2 is 2.

[0230] In the compounds represented by formula (U) and (V), n is 1, R 1 and R 6 is an organic group represented by formula (6-1), R 2 is a connecting group represented by formula (3-1) and p1 is 1, R 5 It is a connecting group represented by formula (3-3) and p2 is 1.

[0231] In the compound represented by formula (U), R 4 is a connecting group represented by formula (4-3) and u1 is 2, R 3 Expressed by formula (5-1).

[0232] In the compound represented by formula (V), R 4 is a connecting group represented by formula (4-1) and s1 is 1, R 3 Expressed by formula (5-2).

[0233] In the compounds represented by formula (W) to (Y), n is 2, R 2 is a connecting group represented by formula (3-1) and p1 is 1, R 5 is a connecting group represented by formula (3-3) and p2 is 1, R 4 is a connecting group represented by formula (4-1) and s1 is 1, R 3 Expressed by formula (5-1).

[0234] In the compound represented by formula (W), R 1 and R 6 It is an organic group represented by formula (6-1).

[0235] In the compound represented by formula (X), R 1 and R 6 It is an organic group represented by formula (6-2).

[0236] In the compound represented by formula (Y), R 1 is an organic group represented by formula (6-1), R 6It is hydroxyethyl.

[0237] In the compounds represented by formula (Z), (AA), and (AB), n is 2, R 1 and R 6 It is an organic group represented by formula (6-1).

[0238] In the compound represented by formula (Z), R 2 is a connecting group represented by formula (3-1) and p1 is 2, R 5 is a connecting group represented by formula (3-3) and p2 is 2, R 4 is a connecting group represented by formula (4-1) and s1 is 1, R 3 Expressed by formula (5-1).

[0239] In the compound represented by formula (AA), R 2 is a connecting group represented by formula (3-1) and p1 is 1, R 5 is a connecting group represented by formula (3-3) and p2 is 1, R 1 Side R 4 is a connecting group represented by formula (4-3) and u1 is 2, R 6 Side R 4 is a connecting group represented by formula (4-2) and t1 is 2, R 3 Expressed by formula (5-1).

[0240] In the compound represented by formula (AB), R 2 is a connecting group represented by formula (3-1) and p1 is 1, R 5 is a connecting group represented by formula (3-3) and p2 is 1, R 4 is a connecting group represented by formula (4-1) and s1 is 1, R 3 Expressed by formula (5-2).

[0241]

[0242] (In Rf1 in formula (A), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (B), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (C), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (D), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20.)

[0243]

[0244] (In Rf1 in formula (E), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (F), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (G), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (H), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20.)

[0245]

[0246] (In Rf1 in formula (I), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (J), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (K), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (L), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20.)

[0247]

[0248] (In Rf2 in formula (M), j represents an average degree of polymerization and is 1 to 15.)

[0249] (In Rf3 in formula (N), k represents an average degree of polymerization and is 1 to 10.)

[0250] (In the two Rf1 in formula (O), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20. h and i in the two Rf1 may be different from each other or the same.)

[0251] (In the two Rf1 in formula (P), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20. h and i in the two Rf1 may be different from each other or the same.)

[0252]

[0253] (In the two Rf1 in formula (Q), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20. h and i in the two Rf1 may be different from each other or the same.)

[0254] (In the two Rf1 in formula (R), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20. h and i in the two Rf1 may be different from each other or the same.)

[0255] (In the two Rf1 in formula (S), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20. h and i in the two Rf1 may be different from each other or the same.)

[0256] (In the two Rf1 in formula (T), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20. h and i in the two Rf1 may be different from each other or the same.)

[0257]

[0258] (In the two Rf1 in formula (U), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20. h and i in the two Rf1 may be different from each other or the same.)

[0259] (In the two Rf2 in formula (V), j represents the average degree of polymerization and is 1 to 15. The j in the two Rf2 may be different or the same.)

[0260] (Among the three Rf1 in formula (W), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20. The h and i in the three Rf1 may be different from each other, or may be partially or entirely the same.)

[0261] (Among the three Rf1 in formula (X), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20. The h and i in the three Rf1 may be different from each other, or may be partially or entirely the same.)

[0262]

[0263] (Among the three Rf1 in formula (Y), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20. The h and i in the three Rf1 may be different from each other, or may be partially or entirely the same.)

[0264] (Among the three Rf1 in formula (Z), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20. The h and i in the three Rf1 may be different from each other, or may be partially or entirely the same.)

[0265] (Among the three Rf1 in formula (AA), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20. The h and i in the three Rf1 may be different from each other, or may be partially or entirely the same.)

[0266] (In the three Rf2 in formula (AB), j represents the average degree of polymerization and is 1 to 15. The j in the three Rf2 may be different from each other, or may be partially or entirely the same.)

[0267] The number average molecular weight (Mn) of the fluorinated ether compound of the present embodiment is preferably in the range of 500 to 10,000, and particularly preferably in the range of 1,000 to 5,000. If the number average molecular weight is 500 or more, the lubricating layer made of the lubricant containing the fluorinated ether compound of the present embodiment has excellent heat resistance. The number average molecular weight of the fluorinated ether compound is more preferably 1,000 or more. In addition, if the number average molecular weight is 10,000 or less, the viscosity of the fluorinated ether compound becomes appropriate, and a lubricating layer with a thin film thickness can be easily formed by applying a lubricant containing it. In order to achieve a viscosity that is easy to handle when used as a lubricant, the number average molecular weight of the fluorinated ether compound is preferably 5,000 or less.

[0268] The number average molecular weight (Mn) of the fluorinated ether compound was measured using AVANCE III 400 manufactured by Bruker Biospin Co., Ltd. 1 H-NMR and 19 Specifically, the value measured by 19 The number of repeating units of the PFPE chain was calculated from the integrated value measured by F-NMR, and the number average molecular weight was determined. In the measurement of NMR (nuclear magnetic resonance), the sample was diluted in a hexafluorobenzene / deuterated acetone (4 / 1 v / v) solvent for measurement. 19 The standard for the F-NMR chemical shift was the peak of hexafluorobenzene at -164.7 ppm. 1 The standard of H-NMR chemical shift was the peak of acetone at 2.2 ppm.

[0269] The fluorine-containing ether compound of the present embodiment is preferably subjected to molecular weight fractionation by an appropriate method so that the molecular weight distribution (ratio of weight average molecular weight (Mw) / number average molecular weight (Mn)) becomes 1.3 or less.

[0270] In the present embodiment, the method for molecular weight fractionation is not particularly limited, and for example, molecular weight fractionation by silica gel column chromatography, gel permeation chromatography (GPC), or the like, molecular weight fractionation by supercritical extraction, or the like can be employed.

[0271] "Manufacturing method"

[0272] The method for producing the fluorine-containing ether compound of the present embodiment is not particularly limited, and the fluorine-containing ether compound can be produced by a conventionally known production method. The fluorine-containing ether compound of the present embodiment can be produced, for example, by the following production methods [1] to [3].

[0273] [1] Production method when n=0 in formula (1)

[0274] 〔1-1〕R 1 -R 2 -With R6 -R 5 -Same situation

[0275] First, prepare the R 3 A fluorine-based compound having a hydroxymethyl group (-CH2OH) is disposed at both ends of the corresponding perfluoropolyether chain.

[0276] Next, the hydroxyl group of the hydroxymethyl group disposed at one end of the fluorine-based compound is reacted with a hydroxyl group having R in the formula (1). 1 -R 2 -group (=become R 6 -R 5 -group) of the epoxy compound. Thus, it is possible to obtain 3 The two ends of the corresponding perfluoropolyether chain have 1 -R 2 - the corresponding group (= with R 6 -R 5 -corresponding group).

[0277] As R in formula (1) 1 -R 2 -group (=become R 6 -R 5 As the epoxy compound having a group (i)-(7-1), for example, the compounds represented by the following formulae (7-1) to (7-8) can be used.

[0278] When the fluorine-based compound and the epoxy compound are reacted, the hydroxyl group of the epoxy compound may be protected with an appropriate protecting group and then allowed to react with the fluorine-based compound.

[0279]

[0280] Having the R in formula (1) 1 -R 2 -group (i.e., becoming R 6 -R 5 -) can be used as shown in the following formula (8), wherein R 1 or R 6 The alcohol having the structure corresponding to the terminal group represented by (R in formula (8)) and having R 2 or R 5 The product can be prepared by reacting the corresponding epoxy halide.

[0281]

[0282] (In formula (8), R represents the same as R in general formula (1)1 or R 6 The structure corresponding to the terminal group represented. )

[0283] In addition, the above-mentioned epoxy compound can also be produced, for example, as shown in the following formula (9), by the following method: 1 or R 6 After an alcohol having a structure corresponding to the terminal group represented by (R in formula (9)) is subjected to an addition reaction with allyl glycidyl ether, the compound obtained by the addition reaction is oxidized by allowing meta-chloroperbenzoic acid (mCPBA) to act on it.

[0284]

[0285] (In formula (9), R represents the same as R in general formula (1) 1 or R 6 The structure corresponding to the terminal group represented. )

[0286] In addition, the above-mentioned epoxy compound can also be produced, for example, as shown in the following formula (10), by the following method: 1 or R 6 The alcohol having the structure corresponding to the terminal group represented by (R in formula (10)) and having R 2 or R 5 After the corresponding alkenyl halide is reacted, the obtained compound is allowed to act with m-chloroperbenzoic acid (mCPBA) to be oxidized.

[0287]

[0288] (In formula (10), R represents the same as R in general formula (1) 1 or R 6 The structure corresponding to the terminal group represented. )

[0289] The above-mentioned epoxy compounds can also be used by purchasing commercial products.

[0290] By performing the above steps, the formula (1) in which n=0 and R 1 -R 2 -With R 6 -R 5 -same compound.

[0291] 〔1-2〕R 1 -R 2 -With R 6 -R 5 - Different situations

[0292] First, prepare the R 3A fluorine-based compound having a hydroxymethyl group (-CH2OH) is disposed at both ends of the corresponding perfluoropolyether chain.

[0293] Next, the hydroxyl group of the hydroxymethyl group disposed at one end of the fluorine-based compound is reacted with a hydroxyl group having R in the formula (1). 1 -R 2 - group of epoxy compounds of the reaction. Thus, can be obtained with R 3 One end of the corresponding perfluoropolyether chain has 1 -R 2 - the corresponding intermediate compound 1 (first reaction).

[0294] For the R 1 -R 2 For epoxy compounds containing a - group, the hydroxyl group can be protected with an appropriate protecting group and then reacted with the above-mentioned fluorine-based compound.

[0295] Next, the intermediate compound 1 is reacted with a compound having a R 6 -R 5 - is reacted with an epoxy compound of the group (second reaction).

[0296] By performing the above steps, the formula (1) in which n=0 and R 1 -R 2 -With R 6 -R 5 -Different compounds.

[0297] [2] Production method when n=1 in formula (1)

[0298] 〔2-1〕R 3 The two PFPE chains represented are identical and R 1 -R 2 -With R 6 -R 5 -Same situation

[0299] First, in the same manner as the above-mentioned manufacturing method [1-2], a 3 One end of the corresponding perfluoropolyether chain has 1 -R 2 - corresponding group (i.e., also with R 6 -R 5 -corresponding group) to produce intermediate compound 1 (first reaction).

[0300] Then, the intermediate compound 1 and the compound having R 4 The corresponding epoxy halide or diepoxy compound is reacted (second reaction). 4The corresponding epoxy halide includes epibromohydrin, epichlorohydrin, chloroethyl oxirane, bromoethyl oxirane and the like. 4 Examples of the corresponding diepoxy compounds include diglycidyl ether and the like.

[0301] By carrying out the above steps, it is possible to obtain the formula (1) wherein n=1, R 3 The two PFPE chains represented are identical and R 1 -R 2 -With R 6 -R 5 -same compound.

[0302] 〔2-2〕R 1 With R 6 , R 2 With R 5 , R 3 When at least one of the two PFPE chains represented is different

[0303] First, in the same manner as the above-mentioned manufacturing method [1-2], a 1 Side R 3 One end of the corresponding perfluoropolyether chain has 1 -R 2 - the corresponding radical intermediate compound 1a (first reaction).

[0304] Next, the intermediate compound 1a and the compound having R 4 The corresponding epoxy halide or diepoxy compound is reacted to produce 1 Side R 3 One end of the corresponding perfluoropolyether chain has 1 -R 2 - A corresponding group, an intermediate compound 2 having an epoxy group at the other end (second reaction).

[0305] Next, the same operation as the first reaction was performed to produce 6 Side R 3 One end of the corresponding perfluoropolyether chain has 6 -R 5 - Intermediate compound 1b of the corresponding group (third reaction). Then, intermediate compound 2 is reacted with intermediate compound 1b (fourth reaction).

[0306] In the above step, the following method can also be used to prepare the intermediate compound 1a and a compound having R 4 After reacting with the corresponding alkenyl halide, the obtained compound is oxidized to form an epoxide compound, and the epoxide compound is reacted with the intermediate compound 1b.4 Examples of the corresponding alkenyl halides include allyl chloride, allyl bromide, and 1-bromo-3-butene.

[0307] By performing the above steps, it is possible to produce a 1 With R 6 , R 2 With R 5 , R 3 A compound in which at least one of the two PFPE chains represented is different.

[0308] [3] Production method when n=2 in formula (1)

[0309] 〔3-1〕R 3 The three PFPE chains represented are the same, R 1 -R 2 -With R 6 -R 5 -same and R 4 The two connecting groups represented are the same

[0310] First, prepare R at the center of the molecule in formula (1) 3 A fluorine-based compound having a hydroxymethyl group (-CH2OH) is disposed at both ends of the corresponding perfluoropolyether chain.

[0311] Next, the hydroxyl groups of the hydroxymethyl groups disposed at both ends of the fluorine-based compound and the 4 The corresponding epoxy halide is reacted (first reaction). Thus, R in the center of the molecule in formula (1) can be obtained. 3 The corresponding intermediate compound 3 has epoxy groups at both ends of the perfluoropolyether chain.

[0312] Next, the same method as the above-mentioned manufacturing method [1-2] is carried out to manufacture a 1 Side R 3 (i.e., R 6 Side R 3 ) has a terminal end of the corresponding perfluoropolyether chain having a 1 -R 2 - corresponding group (i.e., also with R 6 -R 5 -corresponding group) to produce intermediate compound 1 (second reaction).

[0313] Then, the hydroxyl group of the hydroxymethyl group disposed at one end of the intermediate compound 1 is reacted with the epoxy groups disposed at both ends of the intermediate compound 3 (third reaction).

[0314] By carrying out the above steps, it is possible to produce 3The three PFPE chains represented are the same, R 1 -R 2 -With R 6 -R 5 -same and R 4 Here, the order of the first reaction and the second reaction may be reversed.

[0315] 〔3-2〕R 4 The two connecting groups represented by 1 With R 6 , R 2 With R 5 , R 3 When any one or more of the three PFPE chains represented are different

[0316] First, the intermediate compound 3 is obtained in the same manner as in the first reaction of the above-mentioned production method [3-1]. Next, in the second reaction of the above-mentioned production method [3-1], the intermediate compound 3 is synthesized in the presence of R 1 Side R 3 One end of the corresponding perfluoropolyether chain has 1 -R 2 - the corresponding intermediate compound 1a, and in the presence of R 6 Side R 3 One end of the corresponding perfluoropolyether chain has 6 -R 5 - Intermediate compound 1b having a corresponding group. Then, in the third reaction of the above-mentioned production method [3-1], intermediate compound 1a and intermediate compound 1b are reacted in sequence with respect to the epoxy groups disposed at the respective terminals of intermediate compound 3.

[0317] By carrying out the above steps, it is possible to produce 4 The two connecting groups represented by 1 With R 6 , R 2 With R 5 , R 3 A compound in which at least one of the three PFPE chains represented is different.

[0318] 〔3-3〕R 3 The three PFPE chains represented are the same, R 1 -R 2 -With R 6 -R 5 -same and R 4 The two connecting groups represented are different

[0319] In the first reaction of the above-mentioned production method [3-1], the hydroxyl group of the hydroxymethyl group disposed at each end of the above-mentioned fluorine-based compound is reacted with R 4 Two halides having epoxy groups corresponding to the two connecting groups represented by are reacted in sequence to obtain intermediate compound 4. Then, in the third reaction of the above-mentioned production method [3-1], the intermediate compound 1 is reacted with epoxy groups disposed at both ends of the intermediate compound 4, and the reaction is carried out in the same manner as in the above-mentioned production method [3-1].

[0320] By carrying out the above steps, it is possible to produce 3 The three PFPE chains represented are the same, R 1 -R 2 -With R 6 -R 5 -same and R 4 The two connecting groups represented are different compounds.

[0321] The fluorine-containing ether compound of the present embodiment is a fluorine-containing ether compound represented by formula (1), wherein 3 The backbone of the PFPE chain (-CH2-R 3 [-CH2-R 4 -CH2-R 3 ] n -CH2-) are sequentially bonded to both sides of the 2 , R 5 and the terminal group R 1 , R 6 , and at least one terminal group R 1 , R 6 It is a condensed aromatic group including an amide or an ester represented by formula (2). Therefore, the lubricating layer formed on the protective layer using the lubricant including the fluorine-containing ether compound of the present embodiment has good chemical resistance and suppresses adhesion.

[0322] [Lubricant for magnetic recording media]

[0323] The lubricant for magnetic recording media according to the present embodiment contains the fluorine-containing ether compound represented by the above formula (1).

[0324] The lubricant of the present embodiment may be mixed with a known material used as a lubricant as necessary within a range not impairing the properties achieved by including the fluorine-containing ether compound represented by the above formula (1).

[0325] Specific examples of known materials include FOMBLIN (registered trademark) ZDIAC, FOMBLIN ZDEAL, FOMBLIN AM-2001 (all manufactured by Solvay Solexis), Moresco A20H (manufactured by Moresco), etc. The number average molecular weight of the known material used in combination with the lubricant of the present embodiment is preferably 1,000 to 10,000.

[0326] When the lubricant of the present embodiment contains a material other than the fluorinated ether compound represented by the above formula (1), the content of the fluorinated ether compound represented by the above formula (1) in the lubricant of the present embodiment is preferably 50% by mass or more, more preferably 70% by mass or more.

[0327] Since the lubricant of the present embodiment contains the fluorine-containing ether compound represented by the above formula (1), it is possible to form a lubricating layer which has excellent resistance to chemical substances and is excellent in suppressing adhesion.

[0328] [Magnetic recording media]

[0329] The magnetic recording medium of the present embodiment is a medium in which at least a magnetic layer, a protective layer, and a lubricating layer are provided in this order on a substrate.

[0330] In the magnetic recording medium of this embodiment, one or more underlayers may be provided between the substrate and the magnetic layer as required. In addition, at least one of an adhesion layer and a soft magnetic layer may be provided between the underlayer and the substrate.

[0331] Figure 1 This is a schematic cross-sectional view showing one embodiment of the magnetic recording medium of the present invention.

[0332] The magnetic recording medium 10 of the present embodiment has a structure in which an adhesion layer 12 , a soft magnetic layer 13 , a first underlayer 14 , a second underlayer 15 , a magnetic layer 16 , a protective layer 17 , and a lubricating layer 18 are sequentially provided on a substrate 11 .

[0333] "Substrate"

[0334] As the substrate 11 , for example, a non-magnetic substrate in which a film made of NiP or a NiP alloy is formed on a base made of a metal or alloy material such as Al or an Al alloy can be used.

[0335] In addition, as the substrate 11, a non-magnetic substrate made of non-metallic materials such as glass, ceramics, silicon, silicon carbide, carbon, and resin can be used, and a non-magnetic substrate obtained by forming a film of NiP or NiP alloy on a base made of these non-metallic materials can also be used.

[0336] The glass substrate has rigidity and excellent smoothness, and is therefore suitable for high recording density. Examples of the glass substrate include aluminosilicate glass substrates, and chemically strengthened aluminosilicate glass substrates are particularly suitable.

[0337] The roughness of the main surface of the substrate 11 is preferably ultra-smooth with Rmax of 6 nm or less and Ra of 0.6 nm or less. It should be noted that the surface roughness Rmax and Ra referred to herein are values ​​defined in accordance with JIS B0601.

[0338] "Attachment Layer"

[0339] The adhesion layer 12 prevents the substrate 11 from being corroded when the substrate 11 and the soft magnetic layer 13 provided on the adhesion layer 12 are arranged in contact with each other.

[0340] The material of the adhesion layer 12 can be appropriately selected from, for example, Cr, Cr alloy, Ti, Ti alloy, CrTi, NiAl, AlRu alloy, etc. The adhesion layer 12 can be formed by, for example, sputtering.

[0341] "Soft magnetic layer"

[0342] The soft magnetic layer 13 preferably has a structure in which a first soft magnetic film, an intermediate layer composed of a Ru film, and a second soft magnetic film are stacked in sequence. That is, the soft magnetic layer 13 preferably has a structure in which the upper and lower soft magnetic films of the intermediate layer are antiferromagnetically coupled (AFC) by sandwiching an intermediate layer composed of a Ru film between two soft magnetic films.

[0343] Examples of the material of the first soft magnetic film and the second soft magnetic film include CoZrTa alloy and CoFe alloy.

[0344] Preferably, any one of Zr, Ta and Nb is added to the CoFe alloy used for the first soft magnetic film and the second soft magnetic film, thereby promoting amorphization of the first soft magnetic film and the second soft magnetic film, improving the orientation of the first base layer (seed layer), and reducing the flying height of the magnetic head.

[0345] The soft magnetic layer 13 can be formed by, for example, a sputtering method.

[0346] "1st base layer"

[0347] The first underlayer 14 is a layer for controlling the orientation and crystal size of the second underlayer 15 and the magnetic layer 16 provided thereon.

[0348] Examples of the first base layer 14 include a Cr layer, a Ta layer, a Ru layer, a CrMo alloy layer, a CoW alloy layer, a CrW alloy layer, a CrV alloy layer, and a CrTi alloy layer.

[0349] The first underlayer 14 can be formed by, for example, sputtering.

[0350] "Second base layer"

[0351] The second underlayer 15 is a layer for controlling the orientation of the magnetic layer 16 to be favorable. The second underlayer 15 is preferably a layer composed of Ru or a Ru alloy.

[0352] The second base layer 15 may be composed of a single layer or a plurality of layers. When the second base layer 15 is composed of a plurality of layers, all the layers may be composed of the same material, or at least one layer may be composed of a different material.

[0353] The second underlayer 15 can be formed by, for example, sputtering.

[0354] "Magnetic layer"

[0355] The magnetic layer 16 is a magnetic film whose easy magnetization axis is oriented vertically or horizontally to the substrate surface. The magnetic layer 16 is a layer containing Co and Pt, and may also be a layer containing oxide, Cr, B, Cu, Ta, Zr, etc. to improve SNR characteristics.

[0356] Examples of the oxide contained in the magnetic layer 16 include SiO 2 , SiO, Cr 2 O 3 , CoO, Ta 2 O 3 , and TiO 2 .

[0357] The magnetic layer 16 may be composed of a single layer or a plurality of magnetic layers including materials having different compositions.

[0358] For example, when the magnetic layer 16 is composed of three layers, namely, the first magnetic layer, the second magnetic layer, and the third magnetic layer, which are stacked in sequence from the bottom, the first magnetic layer is preferably a granular structure composed of a material containing Co, Cr, Pt and also containing an oxide. As the oxide contained in the first magnetic layer, it is preferred to use, for example, oxides of Cr, Si, Ta, Al, Ti, Mg, Co, etc. Among them, TiO2, Cr2O3, SiO2, etc. can be particularly suitably used. In addition, the first magnetic layer is preferably composed of a composite oxide to which two or more oxides are added. Among them, Cr2O3-SiO2, Cr2O3-TiO2, SiO2-TiO2, etc. can be particularly suitably used.

[0359] The first magnetic layer may contain at least one element selected from the group consisting of B, Ta, Mo, Cu, Nd, W, Nb, Sm, Tb, Ru, and Re in addition to Co, Cr, Pt, and oxides.

[0360] The second magnetic layer can be made of the same material as that of the first magnetic layer. The second magnetic layer preferably has a granular structure.

[0361] The third magnetic layer is preferably a non-granular structure composed of a material containing Co, Cr, Pt and no oxide. The third magnetic layer may contain at least one element selected from B, Ta, Mo, Cu, Nd, W, Nb, Sm, Tb, Ru, Re and Mn in addition to Co, Cr and Pt.

[0362] When the magnetic layer 16 is formed of a plurality of magnetic layers, a non-magnetic layer is preferably provided between adjacent magnetic layers. When the magnetic layer 16 is composed of three layers, namely, a first magnetic layer, a second magnetic layer, and a third magnetic layer, a non-magnetic layer is preferably provided between the first magnetic layer and the second magnetic layer, and between the second magnetic layer and the third magnetic layer.

[0363] The non-magnetic layer arranged between adjacent magnetic layers of the magnetic layer 16 can be appropriately made of, for example, Ru, Ru alloy, CoCr alloy, CoCrX1 alloy (X1 represents at least one element selected from Pt, Ta, Zr, Re, Ru, Cu, Nb, Ni, Mn, Ge, Si, O, N, W, Mo, Ti, V, Zr and B).

[0364] In the non-magnetic layer provided between adjacent magnetic layers of the magnetic layer 16, an alloy material containing oxide, metal nitride or metal carbide is preferably used. Specifically, as oxides, for example, SiO2, Al2O3, Ta2O5, Cr2O3, MgO, Y2O3, TiO2, etc. can be used. As metal nitrides, for example, AlN, Si3N4, TaN, CrN, etc. can be used. As metal carbides, for example, TaC, BC, SiC, etc. can be used.

[0365] The nonmagnetic layer can be formed by, for example, a sputtering method.

[0366] In order to achieve a higher recording density, the magnetic layer 16 is preferably a perpendicular magnetic recording magnetic layer in which the easy magnetization axis is oriented perpendicular to the substrate surface. The magnetic layer 16 may also be an in-plane magnetic recording magnetic layer.

[0367] The magnetic layer 16 can be formed by any conventionally known method such as vapor deposition, ion beam sputtering, magnetron sputtering, etc. The magnetic layer 16 is usually formed by sputtering.

[0368] "Protective layer"

[0369] The protective layer 17 protects the magnetic layer 16. The protective layer 17 may be composed of one layer or multiple layers. As the protective layer 17, a carbon-based protective layer may be preferably used, and an amorphous carbon protective layer is particularly preferred. If the protective layer 17 is a carbon-based protective layer, the interaction with the polar groups (especially hydroxyl groups) contained in the fluorine-containing ether compound in the lubricating layer 18 is further increased, so it is preferred.

[0370] The adhesion between the carbon-based protective layer and the lubricating layer 18 can be controlled by making the carbon-based protective layer hydrogenated carbon and / or carbon nitride and adjusting the hydrogen content and / or nitrogen content in the carbon-based protective layer. The hydrogen content in the carbon-based protective layer is preferably 3 atomic % to 20 atomic % when measured by hydrogen forward scattering (HFS). In addition, the nitrogen content in the carbon-based protective layer is preferably 4 atomic % to 15 atomic % when measured by X-ray photoelectron spectroscopy (XPS).

[0371] The hydrogen and / or nitrogen contained in the carbon-based protective layer does not need to be uniformly contained in the entire carbon-based protective layer. The carbon-based protective layer is preferably a composition gradient layer in which nitrogen is contained on the lubricating layer 18 side of the protective layer 17 and hydrogen is contained on the magnetic layer 16 side of the protective layer 17. In this case, the adhesion between the magnetic layer 16 and the lubricating layer 18 and the carbon-based protective layer is further improved.

[0372] The protective layer 17 preferably has a thickness of 1 nm to 7 nm. When the protective layer 17 has a thickness of 1 nm or more, sufficient performance as the protective layer 17 can be obtained. When the protective layer 17 has a thickness of 7 nm or less, this is preferred from the viewpoint of reducing the thickness of the protective layer 17.

[0373] As a film-forming method of the protective layer 17, a sputtering method using a target containing carbon, a CVD (chemical vapor deposition) method using a hydrocarbon raw material such as ethylene and toluene, an IBD (ion beam deposition) method, or the like can be used.

[0374] When a carbon-based protective layer is formed as the protective layer 17, the protective layer 17 can be formed by, for example, a DC magnetron sputtering method. In particular, when a carbon-based protective layer is formed as the protective layer 17, it is preferable to form an amorphous carbon protective layer by a plasma CVD method. The surface of the amorphous carbon protective layer formed by the plasma CVD method is uniform and has little roughness.

[0375] "Lubricating layer"

[0376] The lubricating layer 18 prevents contamination of the magnetic recording medium 10. In addition, the lubricating layer 18 reduces the frictional force of the magnetic head of the magnetic recording and reproducing device sliding on the magnetic recording medium 10, thereby improving the durability of the magnetic recording medium 10.

[0377] like Figure 1As shown, the lubricating layer 18 is formed in contact with the protective layer 17. The lubricating layer 18 is formed by applying the lubricant for a magnetic recording medium of the above-mentioned embodiment onto the protective layer 17. Therefore, the lubricating layer 18 contains the above-mentioned fluorine-containing ether compound.

[0378] When the protective layer 17 disposed under the lubricating layer 18 is a carbon-based protective layer, the lubricating layer 18 is bonded to the protective layer 17 with a particularly high bonding force. As a result, it is easy to obtain a magnetic recording medium 10 in which the surface of the protective layer 17 is coated with a high coating rate even if the lubricating layer 18 is thin, and the surface contamination of the magnetic recording medium 10 can be effectively prevented.

[0379] The average film thickness of the lubricating layer 18 is preferably More preferably If the average film thickness of the lubricating layer 18 is more than 0.5nm, the lubricating layer 18 will not become an island or a mesh shape but will be formed with a uniform film thickness. Therefore, the surface of the protective layer 17 can be coated with a high coverage rate by the lubricating layer 18. In addition, by making the average film thickness of the lubricating layer 18 below 2.0nm, the lubricating layer 18 can be fully filmized, and the floating amount of the magnetic head can be fully reduced.

[0380] "Method for forming a lubricating layer"

[0381] The lubricating layer 18 can be formed by, for example, preparing a magnetic recording medium in the process of production in which each layer up to the protective layer 17 is formed on the substrate 11 , and applying a lubricating layer forming solution on the protective layer 17 .

[0382] The lubricant layer-forming solution can be obtained by dispersing and dissolving the lubricant for a magnetic recording medium according to the above embodiment in a solvent as necessary to adjust the viscosity and concentration to be suitable for a coating method.

[0383] Examples of the solvent used in the lubricating layer forming solution include fluorine-based solvents such as Batler (registered trademark) XF (trade name, manufactured by Mitsui Dupont Fluoro Chemical Co., Ltd.) and Asahicrine (registered trademark) AE-3000 (trade name, manufactured by AGC Corporation).

[0384] The coating method of the lubricating layer forming solution is not particularly limited, and examples thereof include spin coating, spraying, paper coating, and dipping.

[0385] When the dipping method is adopted, for example, the following method can be adopted. First, the substrate 11 on which each layer up to the protective layer 17 is formed is dipped in the lubricating layer forming solution loaded into the dipping tank of the dipping device. Then, the substrate 11 is pulled out of the dipping tank at a predetermined speed. Thus, the lubricating layer forming solution is applied to the surface of the substrate 11 on the protective layer 17.

[0386] By adopting the dipping method, the lubricating layer-forming solution can be uniformly applied to the surface of the protective layer 17 , and the lubricating layer 18 can be formed on the protective layer 17 with a uniform film thickness.

[0387] In the present embodiment, it is preferable to perform heat treatment on the substrate 11 formed with the lubricating layer 18. By performing the heat treatment, the adhesion between the lubricating layer 18 and the protective layer 17 is improved, and the adhesion between the lubricating layer 18 and the protective layer 17 is improved.

[0388] The heat treatment temperature is preferably set to 100° C. to 180° C., and more preferably set to 100° C. to 160° C. If the heat treatment temperature is 100° C. or higher, the effect of improving the adhesion between the lubricating layer 18 and the protective layer 17 can be fully obtained. In addition, by setting the heat treatment temperature to 180° C. or lower, thermal decomposition of the lubricating layer 18 can be prevented. The heat treatment time can be appropriately adjusted according to the heat treatment temperature, and is preferably set to 10 minutes to 120 minutes.

[0389] In this embodiment, in order to further improve the adhesion of the lubricating layer 18 to the protective layer 17, the lubricating layer 18 may be irradiated with ultraviolet light (UV) before or after the heat treatment.

[0390] The magnetic recording medium 10 of the present embodiment is a medium obtained by sequentially arranging at least a magnetic layer 16, a protective layer 17 and a lubricating layer 18 on a substrate 11. In the magnetic recording medium 10 of the present embodiment, a lubricating layer 18 containing the above-mentioned fluorine-containing ether compound is formed in contact with the protective layer 17. Even if the lubricating layer 18 has a thin film thickness, it has excellent adhesion, and has good chemical resistance and adhesion inhibition effects. Therefore, the reliability of the magnetic recording medium 10 of the present embodiment, especially the inhibition of silicon contamination and durability are excellent. Therefore, the magnetic head floating amount of the magnetic recording medium 10 of the present embodiment is low (for example, less than 10nm), and it can work stably for a long time even in a harsh environment with diversified uses. Therefore, the magnetic recording medium 10 of the present embodiment is particularly suitable as a magnetic disk mounted in a magnetic disk device of the LUL (LoadUnload) method.

[0391] Example

[0392] Hereinafter, the present invention will be described in more detail using Examples and Comparative Examples. It should be noted that the present invention is not limited to the following Examples.

[0393] [Example 1]

[0394] The compound represented by the above formula (A) can be obtained by the method shown below.

[0395] Under nitrogen atmosphere, HOCH2CF2O (CF2CF2O) was added into a 100 mL eggplant-shaped bottle. h (CF2O) i 20 g of a compound represented by CF2CH2OH (wherein h represents the average degree of polymerization and i represents the average degree of polymerization, respectively) (number average molecular weight 1000, molecular weight distribution 1.1), 4.34 g of a compound represented by the above formula (7-1) and 20 mL of tert-butyl alcohol were stirred at room temperature until uniformity was obtained to prepare a mixture. 1.12 g of potassium tert-butylate was added to the mixture, and the mixture was stirred at 70°C for 16 hours to react (first reaction).

[0396] It should be noted that the compound represented by formula (7-1) is synthesized by reacting 7-hydroxyquinolinone with epibromohydrin.

[0397] After the reaction, the obtained reaction product was returned to room temperature, transferred to a separatory funnel containing 100 mL of water, and extracted three times with 100 mL of ethyl acetate. The organic layer was washed with water and dehydrated with anhydrous sodium sulfate. After filtering out the desiccant, the filtrate was concentrated and the residue was purified by silica gel column chromatography to obtain 9.73 g of the compound represented by the following formula (11) as an intermediate compound.

[0398]

[0399] (In Rf1 in formula (11), h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.)

[0400] Next, in a nitrogen atmosphere, 9.74 g of the compound represented by the formula (11) obtained above as an intermediate compound, 1.62 g of the compound represented by the following formula (12) and 10 mL of tert-butanol were added to a 100 mL eggplant-shaped bottle and stirred at room temperature until it became uniform. 0.45 g of potassium tert-butoxide was added to the uniform liquid, and stirred at 70° C. for 23 hours to react (second reaction).

[0401] The compound represented by formula (12) is synthesized by oxidizing a compound in which ethylene glycol monoallyl ether is protected with dihydropyran.

[0402]

[0403] After the reaction, the obtained reaction solution was returned to room temperature, 18 g of 10% hydrogen chloride / methanol solution (hydrogen chloride-methanol reagent (5-10%) manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and stirred at room temperature for 2 hours. It was transferred to a separatory funnel filled with 100 mL of water and extracted three times with 100 mL of ethyl acetate. The organic layer was washed with water and dehydrated with anhydrous sodium sulfate. After filtering out the desiccant, the filtrate was concentrated and the residue was purified by silica gel column chromatography to obtain 5.11 g of compound (A) (in Rf1 in formula (A), h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0404] The obtained compound (A) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0405] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (17H), 4.10-4.20 (4H), 6.30-7.80 (6H)

[0406] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0407] [Example 2]

[0408] The compound represented by the above formula (B) can be obtained by the method shown below.

[0409] The same operation as in Example 1 was performed except that the compound represented by formula (7-2) was used instead of the compound represented by formula (7-1) in Example 1, to obtain 4.89 g of compound (B) (in Rf1 in formula (B), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5).

[0410] It should be noted that the compound represented by formula (7-2) is synthesized by reacting 7-hydroxycoumarin with epibromohydrin.

[0411] The obtained compound (B) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0412] 1H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (17H), 4.10-4.20 (4H), 6.30-7.80 (5H)

[0413] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0414] [Example 3]

[0415] The compound represented by the above formula (C) can be obtained by the method shown below.

[0416] The same operation as in Example 1 was performed except that the compound represented by formula (7-3) was used instead of the compound represented by formula (7-1) in Example 1, to obtain 4.96 g of compound (C) (in Rf1 in formula (C), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5).

[0417] It should be noted that the compound represented by formula (7-3) is synthesized by reacting 4-hydroxycoumarin with epibromohydrin.

[0418] The obtained compound (C) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0419] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (17H), 4.10-4.20 (4H), 6.30-7.80 (5H)

[0420] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0421] [Example 4]

[0422] The compound represented by the above formula (D) can be obtained by the method shown below.

[0423] The same operation as in Example 1 was performed except that the compound represented by formula (7-4) was used instead of the compound represented by formula (7-1) in Example 1, to obtain 5.23 g of compound (D) (in Rf1 in formula (D), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5).

[0424] The compound represented by formula (7-4) is synthesized by reacting 4-hydroxy-7-methoxyquinolinone with epibromohydrin.

[0425] The obtained compound (D) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0426] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (20H), 4.10-4.20 (4H), 6.30-7.80 (5H)

[0427] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0428] [Example 5]

[0429] The compound represented by the above formula (E) can be obtained by the method shown below.

[0430] Except for using the compound represented by formula (7-5) instead of the compound represented by formula (7-1) in Example 1, the same operations as in Example 1 were carried out to obtain 5.03 g of compound (E) (in Rf1 in formula (E), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0431] The compound represented by formula (7-5) is synthesized by reacting 4-hydroxy-2H-isoquinolin-1-one with epibromohydrin.

[0432] The obtained compound (E) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0433] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (17H), 4.10-4.20 (4H), 6.30-7.80 (6H)

[0434] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0435] [Example 6]

[0436] The compound represented by the above formula (F) can be obtained by the method shown below.

[0437] The same operation as in Example 1 was performed except that the compound represented by formula (7-6) was used instead of the compound represented by formula (7-1) in Example 1, to obtain 5.28 g of compound (F) (in Rf1 in formula (F), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5).

[0438] It should be noted that the compound represented by formula (7-6) is synthesized by reacting 3-hydroxy-6H-benzo[c]chromen-6-one with epibromohydrin.

[0439] The obtained compound (F) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0440] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (17H), 4.10-4.20 (4H), 6.30-7.80 (8H)

[0441] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0442] [Example 7]

[0443] The compound represented by the above formula (G) can be obtained by the method shown below.

[0444] The compound (G) produced by the side reaction in the first reaction of Example 1 was purified by silica gel column chromatography to obtain 4.22 g of compound (G) (in Rf1 in formula (G), h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0445] The obtained compound (G) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0446] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (12H), 4.10-4.20 (4H), 6.30-7.80 (12H)

[0447] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0448] [Example 8]

[0449] The compound represented by the above formula (H) can be obtained by the method shown below.

[0450] The compound (H) generated by the side reaction in the first reaction of Example 2 was purified by silica gel column chromatography to obtain 4.05 g of compound (H) (in Rf1 in formula (H), h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0451] The obtained compound (H) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0452] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (12H), 4.10-4.20 (4H), 6.30-7.80 (10H)

[0453] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0454] [Example 9]

[0455] The compound represented by the above formula (I) can be obtained by the method shown below.

[0456] The same operation as in Example 1 was carried out except that the compound represented by formula (13) was used instead of the compound represented by formula (12) in Example 1, to obtain 4.52 g of compound (I) (in Rf1 in formula (I), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5).

[0457] The compound represented by formula (13) is synthesized by reacting allyl alcohol with allyl glycidyl ether and then allowing m-chloroperbenzoic acid to act to oxidize one double bond.

[0458]

[0459] The obtained compound (I) is subjected to 1 H-NMR and19 The structure was identified based on the following results by F-NMR measurement.

[0460] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (20H), 4.10-4.20 (4H), 5.20-6.00 (3H), 6.30-7.80 (6H)

[0461] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0462] [Example 10]

[0463] The compound represented by the above formula (J) can be obtained by the method shown below.

[0464] The same operation as in Example 2 was performed except that the compound represented by formula (14) was used instead of the compound represented by formula (12) in Example 2, to obtain 4.65 g of compound (J) (in Rf1 in formula (J), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5).

[0465] It should be noted that the compound represented by formula (14) is synthesized by reacting phenol with epibromohydrin.

[0466]

[0467] The obtained compound (J) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0468] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (12H), 4.10-4.20 (4H), 6.30-7.80 (10H)

[0469] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0470] [Example 11]

[0471] The compound represented by the above formula (K) can be obtained by the method shown below.

[0472] The same operation as in Example 1 was performed except that the compound represented by formula (7-7) was used instead of the compound represented by formula (7-1) in Example 1, to obtain 4.98 g of compound (K) (in Rf1 in formula (K), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5).

[0473] The compound represented by formula (7-7) is synthesized by reacting 7-hydroxyquinolinone with allyl glycidyl ether and then allowing m-chloroperbenzoic acid to act thereon.

[0474] The obtained compound (K) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0475] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (23H), 4.10-4.20 (4H), 6.30-7.80 (6H)

[0476] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0477] [Example 12]

[0478] The compound represented by the above formula (L) can be obtained by the method shown below.

[0479] The same operation as in Example 1 was performed except that the compound represented by formula (7-8) was used instead of the compound represented by formula (7-1) in Example 1, to obtain 4.56 g of compound (L) (in Rf1 in formula (L), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5).

[0480] The compound represented by formula (7-8) is synthesized by reacting 7-hydroxycoumarin with 4-bromo-1-butene and then allowing m-chloroperbenzoic acid to act thereon.

[0481] The obtained compound (L) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0482] 1H-NMR (acetone-D6): δ [ppm] = 1.40-1.80 (4H), 3.40-4.00 (17H), 4.10-4.20 (4H), 6.30-7.80 (5H)

[0483] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0484] [Example 13]

[0485] The compound represented by the above formula (M) can be obtained by the method shown below.

[0486] Instead of HOCH2CF2O (CF2CF2O) of Example 1 h (CF2O) i The compound represented by CF2CH2OH was used instead of HOCH2CF2CF2O (CF2CF2CF2O). j A compound (number average molecular weight 1000, molecular weight distribution 1.1) represented by CF2CF2CH2OH (where j representing the average degree of polymerization is 4.5) was obtained by the same operation as in Example 1 (where Rf2 in the formula (L) represents the average degree of polymerization, j representing the average degree of polymerization is 4.5).

[0487] The obtained compound (M) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0488] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (17H), 4.10-4.20 (4H), 6.30-7.80 (6H)

[0489] 19 F-NMR (acetone-D6): δ [ppm] = -84.0 to -83.0 (18F), -86.4 (4F), -124.3 (4F), -130.0 to -129.0 (9F)

[0490] [Example 14]

[0491] The compound represented by the above formula (N) can be obtained by the method shown below.

[0492] Instead of HOCH2CF2O (CF2CF2O) of Example 2 h (CF2O) iThe compound represented by CF2CH2OH was used instead of HOCH2CF2CF2CF2O (CF2CF2CF2CF2O). k A compound (number average molecular weight 1000, molecular weight distribution 1.1) represented by CF2CF2CF2CH2OH (where k representing the average degree of polymerization is 3.0) was obtained by the same operation as in Example 2 (where Rf3 in the formula (N) represents the average degree of polymerization, k representing the average degree of polymerization is 3.0).

[0493] The obtained compound (N) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0494] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (17H), 4.10-4.20 (4H), 6.30-7.80 (5H)

[0495] 19 F-NMR (acetone-D6): δ [ppm] = -84.0 to -83.0 (16F), -122.5 (4F), -126.0 (12F), -129.0 to -128.0 (4F)

[0496] [Example 15]

[0497] The compound represented by the above formula (O) can be obtained by the method shown below.

[0498] First, 9.98 g of the intermediate compound represented by formula (11) was obtained by the first reaction of Example 1. Next, 9.98 g of the intermediate compound represented by formula (11) obtained above, 0.56 g of epibromohydrin and 10 mL of tert-butyl alcohol were added to a 100 mL eggplant-shaped bottle under a nitrogen atmosphere, and stirred at room temperature until it became uniform. 0.92 g of potassium tert-butylate was added to the uniform liquid, and stirred at 70° C. for 23 hours to react.

[0499] After the reaction, the obtained reaction solution was returned to room temperature, transferred to a separatory funnel containing 100 mL of water, and extracted three times with 100 mL of ethyl acetate. The organic layer was washed with water and dehydrated with anhydrous sodium sulfate. After filtering out the desiccant, the filtrate was concentrated and the residue was purified by silica gel column chromatography to obtain 4.62 g of compound (O) (in the 2 Rf1 in formula (O), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0500] The obtained compound (O) is subjected to 1H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0501] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (18H), 4.10-4.20 (8H), 6.30-7.80 (12H)

[0502] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (18F), -78.5 (4F), -80.5 (4F), -91.0 to -88.5 (36F)

[0503] [Example 16]

[0504] The compound represented by the above formula (P) can be obtained by the method shown below.

[0505] Except for using the compound represented by formula (7-2) instead of the compound represented by formula (7-1) in Example 15, the same operations as in Example 15 were carried out to obtain 4.52 g of compound (P) (among the two Rf1 in formula (P), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0506] The obtained compound (P) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0507] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (18H), 4.10-4.20 (8H), 6.30-7.80 (10H)

[0508] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (18F), -78.5 (4F), -80.5 (4F), -91.0 to -88.5 (36F)

[0509] [Example 17]

[0510] The compound represented by the above formula (Q) can be obtained by the method shown below.

[0511] Under nitrogen atmosphere, HOCH2CF2O (CF2CF2O) was added into a 200 mL eggplant-shaped bottle. h (CF2O) i12 g of a compound represented by CF2CH2OH (wherein h represents the average degree of polymerization and i represents the average degree of polymerization) and 2.43 g of a compound represented by formula (12) and 12 mL of tert-butyl alcohol were stirred at room temperature until the mixture became uniform. 0.67 g of potassium tert-butylate was further added to the uniform liquid, and the mixture was stirred at 70°C for 16 hours to react.

[0512] After the reaction, the obtained reaction product was cooled to 25°C, transferred to a separatory funnel containing 100 mL of water, and extracted three times with 100 mL of ethyl acetate. The organic layer was washed with water and dehydrated with anhydrous sodium sulfate. After filtering out the desiccant, the filtrate was concentrated and the residue was purified by silica gel column chromatography to obtain 5.77 g of an intermediate compound represented by the following formula (15).

[0513]

[0514] (In Rf1 in formula (15), h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.)

[0515] Next, 5.77 g of the intermediate compound represented by formula (15) obtained above, 6.38 g of the compound represented by formula (16) and 10 mL of tert-butanol were placed in a 100 mL eggplant-shaped bottle under a nitrogen atmosphere, and stirred at room temperature until the mixture became uniform. 0.27 g of potassium tert-butoxide was added to the uniform liquid, and the mixture was stirred at 70° C. for 23 hours to react.

[0516] It should be noted that the compound represented by formula (16) was synthesized by reacting the intermediate compound represented by formula (11) obtained by the first reaction of Example 1 with epibromohydrin.

[0517]

[0518] (In Rf1 in formula (16), h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.)

[0519] After the reaction, the obtained reaction solution was returned to room temperature, 5 g of 10% hydrogen chloride / methanol solution (hydrogen chloride-methanol reagent (5-10%) manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and stirred at room temperature for 2 hours. Transferred to a separatory funnel filled with 100 mL of water, and extracted three times with 100 mL of ethyl acetate. The organic layer was washed with water and dehydrated with anhydrous sodium sulfate. After filtering out the desiccant, the filtrate was concentrated and the residue was purified by silica gel column chromatography to obtain 4.35 g of compound (Q) (Among the two Rf1 in formula (Q), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0520] The obtained compound (Q) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0521] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (23H), 4.10-4.20 (8H), 6.30-7.80 (6H)

[0522] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (18F), -78.5 (4F), -80.5 (4F), -91.0 to -88.5 (36F)

[0523] [Example 18]

[0524] The compound represented by the above formula (R) can be obtained by the method shown below.

[0525] The same operations as in Example 17 were performed except that the compound represented by formula (13) was used instead of the compound represented by formula (12) in Example 17, and the compound represented by formula (7-2) was used instead of the compound represented by formula (7-1), to obtain 4.52 g of compound (R) (of the two Rf1 in formula (R), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5).

[0526] The obtained compound (R) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0527] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (26H), 4.10-4.20 (8H), 5.20-6.00 (3H), 6.30-7.80 (5H)

[0528] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (18F), -78.5 (4F), -80.5 (4F), -91.0 to -88.5 (36F)

[0529] [Example 19]

[0530] The compound represented by the above formula (S) can be obtained by the method shown below.

[0531] Except for using the compound represented by formula (7-7) instead of the compound represented by formula (7-1) in Example 15, the same operations as in Example 15 were carried out to obtain 4.52 g of compound (S) (among the two Rf1 in formula (S), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0532] The obtained compound (S) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0533] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (30H), 4.10-4.20 (8H), 6.30-7.80 (12H)

[0534] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (18F), -78.5 (4F), -80.5 (4F), -91.0 to -88.5 (36F)

[0535] [Example 20]

[0536] The compound represented by the above formula (T) can be obtained by the method shown below.

[0537] Except for using the compound represented by formula (7-8) instead of the compound represented by formula (7-1) in Example 15, the same operations as in Example 15 were carried out to obtain 4.52 g of compound (T) (among the two Rf1 in formula (T), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0538] The obtained compound (T) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0539] 1H-NMR (acetone-D6): δ [ppm] = 1.40-1.80 (4H), 3.40-4.00 (18H), 4.10-4.20 (8H), 6.30-7.80 (10H)

[0540] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (18F), -78.5 (4F), -80.5 (4F), -91.0 to -88.5 (36F)

[0541] [Example 21]

[0542] The compound represented by the above formula (U) can be obtained by the method shown below.

[0543] The same operation as in Example 15 was carried out except that 2-(2-bromoethyl)ethylene oxide was used instead of the epibromohydrin in Example 15, to obtain 4.19 g of compound (U) (among the two Rf1 in formula (U), h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0544] The obtained compound (U) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0545] 1 H-NMR (acetone-D6): δ [ppm] = 1.40-1.80 (2H), 3.40-4.00 (18H), 4.10-4.20 (8H), 6.30-7.80 (10H)

[0546] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (18F), -78.5 (4F), -80.5 (4F), -91.0 to -88.5 (36F)

[0547] [Example 22]

[0548] The compound represented by the above formula (V) can be obtained by the method shown below.

[0549] Instead of HOCH2CF2O (CF2CF2O) of Example 15 h (CF2O) i The compound represented by CF2CH2OH was used instead of HOCH2CF2CF2O (CF2CF2CF2O). jA compound (number average molecular weight 1000, molecular weight distribution 1.1) represented by CF2CF2CH2OH (where j representing the average degree of polymerization is 4.5) was obtained by the same operation as in Example 15 to obtain 4.85 g of compound (V) (among the two Rf2 in formula (V), j representing the average degree of polymerization is 4.5).

[0550] The obtained compound (V) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0551] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (18H), 4.10-4.20 (8H), 6.30-7.80 (12H)

[0552] 19 F-NMR (acetone-D6): δ [ppm] = -84.0 to -83.0 (36F), -86.4 (8F), -124.3 (8F), -130.0 to -129.0 (18F)

[0553] [Example 23]

[0554] The compound represented by the above formula (W) can be obtained by the method shown below.

[0555] Make HOCH2CF2O(CF2CF2O) h (CF2O) i A compound represented by CF2CH2OH (wherein h representing the average degree of polymerization is 4.5 and i representing the average degree of polymerization is 4.5) (number average molecular weight 1000, molecular weight distribution 1.1) is reacted with epibromohydrin to obtain an intermediate compound represented by formula (17).

[0556]

[0557] (In Rf1 in formula (17), h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.)

[0558] Next, in the reaction between the intermediate compound represented by formula (11) in Example 15 and epibromohydrin, the same operation as in Example 15 was performed except that the intermediate compound represented by formula (17) was used instead of epibromohydrin to obtain 4.75 g of compound (W) (among the three Rf1 in formula (W), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0559] The obtained compound (W) is subjected to 1H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0560] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (24H), 4.10-4.20 (12H), 6.30-7.80 (12H)

[0561] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (27F), -78.5 (6F), -80.5 (6F), -91.0 to -88.5 (54F)

[0562] [Example 24]

[0563] The compound represented by the above formula (X) can be obtained by the method shown below.

[0564] The same operation as in Example 16 was carried out except that the intermediate compound represented by formula (17) was used instead of the epibromohydrin in Example 16, to obtain 4.55 g of compound (X) (among the three Rf1 in formula (X), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5).

[0565] The obtained compound (X) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0566] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (24H), 4.10-4.20 (12H), 6.30-7.80 (10H)

[0567] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (27F), -78.5 (6F), -80.5 (6F), -91.0 to -88.5 (54F)

[0568] [Example 25]

[0569] The compound represented by the above formula (Y) can be obtained by the method shown below.

[0570] In the reaction of synthesizing the compound represented by formula (16) in Example 17, an intermediate compound represented by formula (17) was used instead of epibromohydrin. The same operations as in Example 17 were performed to obtain 4.23 g of compound (Y) (among the three Rf1 in formula (Y), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0571] The obtained compound (Y) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0572] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (29H), 4.10-4.20 (12H), 6.30-7.80 (6H)

[0573] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (27F), -78.5 (6F), -80.5 (6F), -91.0 to -88.5 (54F)

[0574] [Example 26]

[0575] The compound represented by the above formula (Z) can be obtained by the method shown below.

[0576] The same operation as in Example 19 was carried out except that the intermediate compound represented by formula (17) was used instead of the epibromohydrin in Example 19, to obtain 4.84 g of compound (Z) (among the three Rf1 in formula (Z), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0577] The obtained compound (Z) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0578] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (36H), 4.10-4.20 (12H), 6.30-7.80 (12H)

[0579] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (27F), -78.5 (6F), -80.5 (6F), -91.0 to -88.5 (54F)

[0580] [Example 27]

[0581] The compound represented by the above formula (AA) can be obtained by the method shown below.

[0582] Make HOCH2CF2O(CF2CF2O) h (CF2O) i A compound represented by CF2CH2OH (wherein h represents the average degree of polymerization and i represents the average degree of polymerization, respectively, is 4.5) (number average molecular weight 700, molecular weight distribution 1.1) is reacted with 4-bromo-1-butene and then meta-chloroperbenzoic acid is allowed to act to obtain an intermediate compound represented by formula (18).

[0583]

[0584] (In Rf1 in formula (18), h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.)

[0585] Next, in the reaction between the intermediate compound represented by formula (11) in Example 15 and epibromohydrin, the same operation as in Example 15 was performed except that the intermediate compound represented by formula (18) was used instead of epibromohydrin, to obtain 4.62 g of compound (AA) (among the three Rf1 in formula (AA), h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0586] The obtained compound (AA) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0587] 1 H-NMR (acetone-D6): δ [ppm] = 1.40-1.80 (4H), 3.40-4.00 (24H), 4.10-4.20 (12H), 6.30-7.80 (12H)

[0588] 19 F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (27F), -78.5 (6F), -80.5 (6F), -91.0 to -88.5 (54F)

[0589] [Example 28]

[0590] The compound represented by the above formula (AB) can be obtained by the method shown below.

[0591] Instead of HOCH2CF2O (CF2CF2O) of Example 23 h (CF2O) iThe compound represented by CF2CH2OH was used instead of HOCH2CF2CF2O (CF2CF2CF2O). j A compound (number average molecular weight 1000, molecular weight distribution 1.1) represented by CF2CF2CH2OH (where j representing the average degree of polymerization is 4.5) was obtained by the same operation as in Example 23 (among the three Rf2 in the formula (AB) where j representing the average degree of polymerization is 4.5).

[0592] The obtained compound (AB) is subjected to 1 H-NMR and 19 The structure was identified based on the following results by F-NMR measurement.

[0593] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-4.00 (24H), 4.10-4.20 (12H), 6.30-7.80 (12H)

[0594] 19 F-NMR (acetone-D6): δ [ppm] = -84.0 to -83.0 (54F), -86.4 (12F), -124.3 (12F), -130.0 to -129.0 (27F)

[0595] Table 1 shows the R values ​​of the compounds (A) to (Z), (AA), and (AB) of Examples 1 to 28 obtained in this way when they are respectively matched with the formula (1). 1 ~R 6 The structure and the value of n.

[0596] [Table 1]

[0597]

[0598] [Comparative Example 1]

[0599] According to the method described in Patent Document 1, a compound represented by the following formula (AC) was synthesized.

[0600]

[0601] (In Rf1 in formula (AC), h, which indicates the average degree of polymerization, is 4.5, and i is 4.5.)

[0602] [Comparative Example 2]

[0603] By the method described in Patent Document 2, a compound represented by the following formula (AD) was synthesized.

[0604]

[0605] (In Rf1 in formula (AD), h, which indicates the average degree of polymerization, is 4.5, and i is 4.5.)

[0606] [Comparative Example 3]

[0607] By the method described in Patent Document 3, a compound represented by the following formula (AE) was synthesized.

[0608]

[0609] (In Rf1 in formula (AE), h, which indicates the average degree of polymerization, is 4.5, and i is 4.5.)

[0610] [Comparative Example 4]

[0611] By the method described in Patent Document 4, a compound represented by the following formula (AF) was synthesized.

[0612]

[0613] (In Rf2 in formula (AF), j indicating the average degree of polymerization is 7.0. Me represents a methyl group.)

[0614] [Comparative Example 5]

[0615] By the method described in Patent Document 5, a compound represented by the following formula (AG) was synthesized.

[0616]

[0617] (In the two Rf2 in formula (AG), j indicating the average degree of polymerization is 7.0.)

[0618] The number average molecular weight (Mn) of the compounds of Examples 1 to 28 and Comparative Examples 1 to 5 thus obtained was measured by the above-mentioned method. The results are shown in Tables 2 and 3.

[0619] Next, the compounds obtained in Examples 1 to 28 and Comparative Examples 1 to 5 were used to prepare lubricant layer forming solutions by the method described below. Then, the lubricant layer of the magnetic recording medium was formed by the method described below using the obtained lubricant layer forming solutions, thereby obtaining magnetic recording media of Examples 1 to 28 and Comparative Examples 1 to 5.

[0620] "Lubricating layer forming solution"

[0621] The compounds obtained in Examples 1 to 28 and Comparative Examples 1 to 5 were respectively dissolved in a fluorine-based solvent, Batler (registered trademark) XF (trade name, manufactured by Mitsui Dupont Fluoro Chemical Co., Ltd.), so that the film thickness when applied on the protective layer would be The solution was diluted with Batler XF in a manner of 10 to prepare a lubricating layer forming solution.

[0622] "Magnetic recording media"

[0623] A magnetic recording medium was prepared in which an adhesion layer, a soft magnetic layer, a first underlayer, a second underlayer, a magnetic layer, and a protective layer were sequentially provided on a substrate having a diameter of 65 mm. The protective layer was a layer composed of carbon.

[0624] On the protective layer of the magnetic recording medium having each layer up to the protective layer, the lubricating layer forming solutions of Examples 1 to 28 and Comparative Examples 1 to 5 were applied by dipping. The dipping method was performed under the conditions of dipping speed of 10 mm / sec, dipping time of 30 sec, and pulling speed of 1.2 mm / sec.

[0625] Then, the magnetic recording medium coated with the lubricating layer forming solution is placed in a constant temperature bath and heat treated for 10 minutes (which is to remove the solvent in the lubricating layer forming solution to improve the adhesion between the protective layer and the lubricating layer), thereby forming a lubricating layer on the protective layer to obtain a magnetic recording medium.

[0626] (Film thickness measurement)

[0627] The film thickness of the lubricating layer of the magnetic recording media of Examples 1 to 28 and Comparative Examples 1 to 5 obtained in this manner was measured using FT-IR (trade name: Nicoleti S50, manufactured by Thermo Fisher Scientific).

[0628] (Chemical resistance test)

[0629] The contamination of magnetic recording media by environmental substances that generate contaminants in a high temperature environment was investigated by the following method: Si ions were used as environmental substances, and the amount of Si adsorption was measured as the amount of contaminants generated by the environmental substances and contaminating the magnetic recording medium.

[0630] Specifically, the magnetic recording medium to be evaluated was maintained for 240 hours in the presence of a silicone-based Si rubber in a high temperature environment of 85°C and 0% humidity. Next, the amount of Si adsorption present on the surface of the magnetic recording medium was analyzed and measured using secondary ion mass spectrometry (SIMS), and the degree of contamination caused by Si ions was evaluated in the form of the amount of Si adsorption. In the evaluation of the amount of Si adsorption, the numerical value when the result of Comparative Example 5 was set to 1.00 was used, and the evaluation was performed based on the following evaluation criteria. The results are shown in Tables 2 and 3.

[0631] “Evaluation Benchmarks”

[0632] A: Si adsorption is less than 0.70

[0633] B: Si adsorption amount is 0.70 or more and less than 0.90

[0634] C: Si adsorption amount is 0.90 or more and less than 1.10

[0635] D: Si adsorption amount is 1.10 or more

[0636] (Adhesion inhibition test)

[0637] The magnetic recording medium and the magnetic head were mounted on a rotating frame, and the magnetic head was floated at a fixed point for 10 minutes under normal temperature and reduced pressure (about 250 torr). Then, the surface of the magnetic head opposite to the magnetic recording medium (the surface of the lubricating layer) was analyzed using an ESCA (Electron Spectroscopy for Chemical Analysis) analysis device. Then, based on the intensity (signal intensity (au)) of the peak from fluorine measured by ESCA, the amount of lubricant attached to the magnetic head was evaluated according to the following benchmarks. The results are shown in Tables 2 and 3.

[0638] “Evaluation Benchmarks”

[0639] A: The ESCA signal strength is below 500, which is very small (the amount of lubricant attached to the magnetic head is very small)

[0640] B: ESCA signal intensity is small, 501 or more and 800 or less (the amount of lubricant attached to the magnetic head is small)

[0641] C: ESCA signal strength is 801 or more and 1000 or less, which is slightly larger (the amount of lubricant attached to the magnetic head is slightly large)

[0642] D: ESCA signal intensity is as large as 1001 or more (a large amount of lubricant is attached to the magnetic head)

[0643] [Table 2]

[0644]

[0645] [Table 3]

[0646]

[0647] As shown in Table 2, the magnetic recording media of Examples 1 to 28 were evaluated as A or B in all evaluation items. This confirmed that the lubricating layers of the magnetic recording media of Examples 1 to 28 had good chemical substance resistance and were excellent in suppressing sticking.

[0648] In particular, Examples 7, 8, 15, 16, 20 to 24, 27, and 28 have better chemical resistance than Examples 19 and 26. This is considered to be because R 1 and R 6 These two are fused aromatic groups represented by formula (2) and R 2 and R 5 The number of hydroxyl groups contained in each is 1, that is, R 2 and R 5 The compound has an appropriate number of hydroxyl groups contained therein, and therefore, there are fewer polar groups that do not participate in bonding with the active sites on the protective layer.

[0649] When using R 1 and R 6 Examples 9, 10, and 18 of the compounds in which only one of the compounds is a fused aromatic group represented by formula (2) and the other is an organic group containing a double bond, and the compounds in which R 2 In Example 12, which is a compound of formula (3-2), the chemical resistance is good. This is considered to be because the polarity of the entire molecule is reduced, so the interaction between the polar group that does not participate in the bonding with the active site on the protective layer and Si is weakened.

[0650] The evaluation of the adhesion inhibition test of Examples 15, 16, 19, 22, 23, 24, 26, and 28 was good compared with Examples 20, 21, and 27. This is considered to be because R in Formula (1) was used in Examples 15, 16, 19, 22, 23, 24, 26, and 28. 1 and R 6 These two are a fused aromatic group represented by formula (2), R 2 , R 4 and R 5 The total number of hydroxyl groups contained in is 3 or more and R 2 , R 4 , R 5 At least one of the compounds has a soft glycerol structure (-OCH2CH(OH)CH2O-), whereby the interaction with the protective layer becomes strong.

[0651] In addition, when using R in formula (1), 1 and R 6 These two are fused aromatic groups represented by formula (2) and R 2 and R 5Compared with Examples 7 and 8 of the compounds in which the total number of hydroxyl groups contained in the compounds is 2, Examples 15, 16, 19, 22, 23, 24, 26, and 28 were evaluated well in the adhesion inhibition test. It is believed that this is because in Examples 15, 16, 19, 22, 23, 24, 26, and 28, the number of hydroxyl groups contained in the molecules is appropriate, so sufficient adsorption force to the protective layer is obtained.

[0652] When using R 1 and R 6 In Examples 1, 2, 3, 4, 5, 6, 11, 13, 14, 17, and 25, in which only one of the compounds is a condensed aromatic group represented by formula (2) and the other is an organic group containing a primary hydroxyl group, the evaluation of the adhesion inhibition test is good. This is considered to be because the primary hydroxyl group contained in the above-mentioned compound has a strong adsorption force to the protective layer, so the lubricating layer can be sufficiently adhered to the protective layer.

[0653] In addition, when using R in formula (1), 1 and R 6 Only one of them is a fused aromatic group represented by formula (2) and the other is an organic group containing a primary hydroxyl group, R 2 Compared with Example 12, which is a compound having a structure in which a glycerol structure (-OCH2CH(OH)CH2O-) is carbonized, the evaluation of the adhesion inhibition test of Examples 1, 2, 3, 4, 5, 6, 11, 13, 14, 17, and 25 is good. This is considered to be because in Examples 1, 2, 3, 4, 5, 6, 11, 13, 14, 17, and 25, R 2 , R 4 , R 5 The soft glycerol structure in the film enables a strong interaction between it and the protective layer.

[0654] The compounds of Comparative Examples 1 and 2 have pyridine or amide at both ends of the perfluoropolyether chain via a glycerol structure (-OCH2CH(OH)CH2O-). In Comparative Examples 1 and 2, the evaluation of the chemical resistance test was B, but the evaluation of the adhesion inhibition test was D and C, respectively. This is considered to be because, in Comparative Examples 1 and 2, the terminal pyridine or amide has insufficient adsorption force on the protective layer, and the lubricating layer does not sufficiently adhere to the protective layer.

[0655] The compounds of Comparative Examples 3 and 4 have terminal groups having benzene rings at one or both ends of the perfluoropolyether chain via a glycerol structure (-OCH2CH(OH)CH2O-). In Comparative Examples 3 and 4, the evaluations of the chemical resistance test were D and C, respectively, and the evaluations of the adhesion inhibition test were C and D, respectively. The reason why good results were not obtained in terms of chemical resistance is believed to be that the benzene rings of the terminal groups have almost no polarity, and therefore, almost no interaction between the terminal groups and the protective layer is obtained, and the lubricating layer does not fully infiltrate and spread on the protective layer. In addition, it is believed that since the lubricating layer is not sufficiently in close contact with the protective layer, the adhesion inhibition effect is not fully obtained.

[0656] In the compound of Comparative Example 5, an alkyl chain having 8 carbon atoms and having two hydroxyl groups is arranged in the center of the chain structure, and a perfluoropolyether chain and an end group having two hydroxyl groups and a hydroxyl group arranged at the end of the chain structure are sequentially bonded on both sides. In Comparative Example 5, the evaluations of the chemical resistance test and the adhesion inhibition test were C. It is believed that the reason for this is that there are many hydroxyl groups that do not participate in the bonding with the active site on the protective layer, so Si is easily mixed into the lubricating layer, and the adsorption force to the protective layer becomes insufficient.

[0657] Industrial Availability

[0658] By using the lubricant for a magnetic recording medium containing the fluorine-containing ether compound of the present invention, it is possible to form a lubricating layer which has excellent adhesion even though it is thin, has good resistance to chemical substances, and suppresses sticking.

[0659] Description of Reference Numerals

[0660] 10 Magnetic Recording Media

[0661] 11 base plate

[0662] 12 Adhesion layer

[0663] 13 Soft magnetic layer

[0664] 14 1st basal layer

[0665] 15 Second basal layer

[0666] 16 Magnetic layer

[0667] 17 Protective layer

[0668] 18 Lubrication layer

Claims

1. A fluorine-containing ether compound, characterized in that It is represented by the following formula (1): R 1 -R 2 -CH2-R 3 [-CH2-R 4 -CH2-R 3 ] n -CH2-R 5 -R 6 (1) In formula (1), n ​​is an integer from 0 to 2; R 3 is a perfluoropolyether chain; (n+1) R 3 They may be partially or completely the same, or they may be different; R 4 is a divalent linking group having one or more polar groups; when n is 2, two R 4 Can be the same or different; R 2 and R 5 is a divalent linking group having one or more polar groups; R 2 With R 5 Can be the same or different; R 2 In the R 1 The bonded end has an oxygen atom; R 5 In the R 6 The bonded end has an oxygen atom; R 1 and R 6 For R 2 or R 5 An organic group having 1 to 50 carbon atoms or a hydrogen atom to which the oxygen atom has bonded; R 1 With R 6 Can be the same or different; R 1 and R 6 At least one of them is a structure represented by the following formula (2); In formula (2), one of X and Y is a carbonyl group, i.e., C=O, and the other is -NH-, -NR 7 -or-O-,R 7 represents a hydrocarbon group having 1 to 8 carbon atoms; Q represents a carbon atom contained in the connecting group represented by the arc of the dotted line, and together with X and Y, forms a heterocyclic structure of a 5- to 8-membered ring; Z represents 0 to 5 substituents; Z is independently an organic group having 1 to 8 carbon atoms; Z may be bonded to any carbon atom constituting the two rings in formula (2), excluding the carbonyl carbon atom of X or Y; when there are 2 or more Zs, the two Zs may be bonded to each other to form a ring structure; any of the carbon atoms constituting the two rings in formula (2) is bonded to R 2 or R 5 The terminal oxygen atom of the carbon atom does not include the carbonyl carbon atom of X or Y.

2. The fluorine-containing ether compound according to claim 1, wherein the formula (2) is a structure represented by the following formula (2-1), In formula (2-1), one of X and Y is a carbonyl group, i.e., C=O, and the other is -NH-, -NR 7 -, or -O-, R 7 represents a hydrocarbon group having 1 to 8 carbon atoms; Z is 0 to 5 substituents; Z is independently an organic group having 1 to 8 carbon atoms; Z may be bonded to any carbon atom constituting the two rings in formula (2-1), excluding the carbonyl carbon atom of X or Y; when there are 2 or more Zs, the two Zs may be bonded to each other to form a ring structure; any one of the carbon atoms constituting the two rings in formula (2-1) is bonded to R 2 or R 5 The terminal oxygen atom of the carbon atom does not include the carbonyl carbon atom of X or Y.

3. The fluorinated ether compound according to claim 1, wherein R in the formula (1) 1 With R 6 same.

4. The fluorinated ether compound according to claim 1, wherein R in the formula (1) 1 and R 6 One of them is a structure represented by the formula (2), and the other is not a structure represented by the formula (2) and is an organic group having at least one double bond or triple bond, an alkyl group having 1 to 8 carbon atoms which may have a substituent, or a hydrogen atom. 5 . The fluorine-containing ether compound according to claim 1 , wherein the organic group in Z in the formula (2) is selected from an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkyl group substituted with an aryl group, and an alkoxy group.

6. The fluorinated ether compound according to any one of claims 1 to 4, wherein R in the formula (1) 2 , R 4 and R 5 The polar groups in are all hydroxyl groups.

7. The fluorinated ether compound according to any one of claims 1 to 4, wherein R in the formula (1) 2 , R 4 and R 5 Some or all of the polar groups in are hydroxyl groups, R 2 The hydroxyl groups, R 4 The hydroxyl groups and R 5 The total number of hydroxyl groups contained in the polyol is 2 to 8.

8. The fluorinated ether compound according to any one of claims 1 to 4, wherein R in the formula (1) 2 and R 5 Each is independently a linking group represented by the following formula (3), In formula (3), p represents an integer of 1 to 3; q represents an integer of 1 to 5; r represents an integer of 1 to 5; when p is 2 or more, the combination of q and r in each structural unit may be the same or different; in formula (3), the oxygen atom at the left terminal and the oxygen atom arranged in R in formula (1) are 2 or R 5 R 1 In formula (3), the oxygen atom at the right end is bonded to the group arranged at R in formula (1). 2 or R 5 R 6 Side group bonding.

9. The fluorinated ether compound according to any one of claims 1 to 4, wherein R in the formula (1) 2 is a linking group represented by the following formula (3-1) or (3-2), wherein R 5 is a linking group represented by the following formula (3-3) or (3-4), p1 in formula (3-1) represents an integer of 1 to 3; q1 in formula (3-2) represents an integer of 2 to 4; in formulas (3-1) and (3-2), the oxygen atom at the left terminal and R in formula (1) are 1 Bonding; p2 in formula (3-3) represents an integer of 1 to 3; r2 in formula (3-4) represents an integer of 2 to 4; in formulas (3-3) and (3-4), the oxygen atom at the right terminal and R in formula (1) are 6 Bonding.

10. The fluorinated ether compound according to any one of claims 1 to 4, wherein in the formula (1), (n+1) R 3 is the same, R 1 -R 2 -With R 6 -R 5 -are identical.

11. The fluorinated ether compound according to any one of claims 1 to 4, wherein the n R in the formula (1) 4 Each is independently a linking group represented by the following formula (4), In formula (4), s represents an integer of 1 to 3; t represents an integer of 1 to 5; u represents an integer of 1 to 5; when s is 2 or more, the combination of t and u in each structural unit may be the same or different; in formula (4), the oxygen atom at the left terminal and the oxygen atom arranged in R in formula (1) are 4 R 1 In formula (4), the oxygen atom at the right end is bonded to the group arranged at R in formula (1) 4 R 6 Side group bonding.

12. The fluorinated ether compound according to any one of claims 1 to 4, wherein the n R in the formula (1) 4 Each independently represents a linking group represented by any one of the following formulae (4-1) to (4-3), In formula (4-1), s1 represents an integer from 1 to 3; In formula (4-2), t1 represents an integer of 2 to 4; in formula (4-2), the oxygen atom at the left terminal is bonded to R in formula (1). 4 R 1 A methylene group adjacent to the side; u1 in formula (4-3) represents an integer of 2 to 4; in formula (4-3), the oxygen atom at the right terminal is bonded to R 4 R 6 The methylene group is adjacent to the side.

13. The fluorinated ether compound according to any one of claims 1 to 4, wherein the (n+1) R in the formula (1) 3 Each independently is a perfluoropolyether chain represented by the following formula (5), -(CF2) w1 -O-(CF2O) w2 -(CF2CF2O) w3 -(CF2CF2CF2O) w4 -(CF2CF2CF2CF2O) w5 -(CF2) w6 -(5) In formula (5), w2, w3, w4, and w5 represent average polymerization degrees, and each independently represents 0 to 20; wherein, The case where w2, w3, w4, and w5 are all 0 at the same time is not included; w1 and w6 are the average values ​​of the number of CF2, and each independently represents 1 to 3; the arrangement order of the repeating units (CF2O), (CF2CF2O), (CF2CF2CF2O), and (CF2CF2CF2CF2O) in formula (5) is not particularly limited.

14. The fluorinated ether compound according to any one of claims 1 to 4, wherein the (n+1) R in the formula (1) 3 Each independently represents any one perfluoropolyether chain selected from the perfluoropolyether chains represented by the following formulae (5-1) to (5-4), -CF2-(OCF2CF2) h -(OCF2) i -OCF2-(5-1) In formula (5-1), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20; -CF2CF2-(OCF2CF2CF2) j -OCF2CF2-(5-2) In formula (5-2), j represents the average degree of polymerization and is 1 to 15; -CF2CF2CF2-(OCF2CF2CF2CF2) k -OCF2CF2CF2-(5-3) In formula (5-3), k represents an average degree of polymerization and is 1 to 10; -(CF2) w7 -O-(CF2CF2CF2O) w8 -(CF2CF2O) w9 -(CF2) w10 -(5-4) In formula (5-4), w8 and w9 represent average polymerization degrees and are each independently 1 to 20; w7 and w10 represent average values ​​of the number of CF2 and are each independently 1 to 2. 15 . The fluorine-containing ether compound according to claim 1 , which has a number average molecular weight in the range of 500 to 10,000.

16. A lubricant for a magnetic recording medium, characterized in that: The fluorine-containing ether compound according to any one of claims 1 to 4.

17. A magnetic recording medium, characterized in that: At least a magnetic layer, a protective layer and a lubricating layer are sequentially arranged on the substrate. The lubricating layer comprises the fluorine-containing ether compound according to any one of claims 1 to 4. 18 . The magnetic recording medium according to claim 17 , wherein the lubricating layer has an average film thickness of 0.5 nm to 2.0 nm.

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