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

Abstract

A fluorine-containing ether compound represented by formula (1). (1), R1-CH2-R2-CH2-R3 (1), (2), (3). And R2 is a perfluoropolyether chain. And R1 and R3 each represents a terminal group having 1 to 4 polar groups and having 1 to 50 carbon atoms. And at least one of R1 and R3 is a terminal group represented by formula (2). And-O-X-CH (OH)-CH2OH (2), as shown in the specification. And X represents a divalent organic group having 2-30 carbon atoms, which may include at least one of 1-2 polar groups and 1-3 ether oxygen atoms. And X contains at least one carbon atom that is not bonded to both a polar group and an ether oxygen atom.

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. 2023-074981 filed in Japan on April 28, 2023, the contents of which are incorporated herein by reference. Background Art

[0003] In order to improve the recording density of magnetic recording and reproducing devices, the development of magnetic recording media with high recording density is suitable. In the past, as magnetic recording media, there is a material in which a recording layer is formed on a substrate and a protective layer of carbon or the like is formed 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 a protective layer on the recording layer. Therefore, generally speaking, a lubricant is applied on the surface of the protective layer to form a lubricating layer.

[0004] As a lubricant used when forming a lubricating layer of a magnetic recording medium, for example, a lubricant containing a compound having a polar group such as a hydroxyl group or an amino group at the terminal of a fluorine-based polymer having a repeating structure containing -CF2- has been proposed.

[0005] For example, Patent Documents 1 and 2 disclose fluorinated ether compounds having a glycerol linking group (-O-CH2-CH(OH)-CH2-O-) and an organic group as an end group having a polar group bonded sequentially to both ends of a perfluoropolyether chain via a methylene group (-CH2-).

[0006] Patent Document 3 discloses that a structure including a glycerol linking group having carbon added (-O-CH2-CH(OH)-CH2-(CH2)) is sequentially bonded to both ends of a perfluoropolyether chain via a methylene group (-CH2-). n -O-) linking group, and a fluorine-containing ether compound of a terminal group.

[0007] Patent Document 4 discloses a fluorine-containing ether compound having one or more glycerol structures bonded to both ends of a perfluoropolyether chain via a methylene group (—CH 2 —).

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: International Publication No. 2021 / 090940 (A)

[0011] Patent Document 2: Japanese Patent No. 6804893 (B)

[0012] Patent Document 3: International Publication No. 2019 / 054148 (A)

[0013] Patent Document 4: International Publication No. 2009 / 013785 (A) Summary of the invention

[0014] Problems to be solved by the invention

[0015] In recent years, in order to increase the capacity of magnetic recording media, it is required to further reduce the magnetic gap (the distance between the magnetic head and the magnetic layer of the magnetic recording medium). Therefore, it is required to make the thickness of the lubricating layer in the magnetic recording medium thinner.

[0016] However, generally speaking, if the thickness of the lubricating layer is made thin, there is a tendency that the corrosion resistance of the magnetic recording medium is reduced. In addition, if the lubricating layer is made thin, if it falls off (a phenomenon in which the lubricant is scattered or evaporated due to the centrifugal force and heat generated by the rotation of the magnetic recording medium), it is sometimes impossible to maintain a sufficient film thickness to satisfy the function of the lubricating layer. Therefore, a lubricating layer that has excellent corrosion resistance and can suppress shedding is required even when the thickness of the lubricating layer is made thin.

[0017] 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 corrosion resistance and can suppress peeling and can be suitably used as a material for a lubricant for a magnetic recording medium.

[0018] An object of the present invention is to provide a lubricant for a magnetic recording medium which contains the fluorine-containing ether compound of the present invention and can form a lubricating layer having excellent corrosion resistance and which can be prevented from coming off.

[0019] An object of the present invention is to provide a magnetic recording medium having a lubricating layer containing the fluorinated ether compound of the present invention, which has excellent corrosion resistance and can suppress peeling.

[0020] Means for solving problems

[0021] The present invention includes the following aspects.

[0022] [1] A fluorine-containing ether compound characterized by being represented by the following formula (1).

[0023] R 1 -CH2-R 2 -CH2-R 3 (1)

[0024] (In formula (1), R 2 R is a perfluoropolyether chain. 1 and R 3 It is a terminal group having 1 to 4 polar groups and 1 to 50 carbon atoms. 1 and R 3They can be the same or different. 1 and R 3 At least one of them is a terminal group represented by the following formula (2).

[0025] -OX-CH(OH)-CH2OH (2)

[0026] (In formula (2), X is a divalent organic group having 2 to 30 carbon atoms which may contain at least one of 1 to 2 polar groups and 1 to 3 etheric oxygen atoms. X contains at least one carbon atom which is not bonded to either a polar group or an etheric oxygen atom.)

[0027] [2] The fluorinated ether compound according to [1], wherein the terminal group represented by the formula (2) is any one of the following formulas (2-1) to (2-7).

[0028]

[0029] (In formula (2-1), a represents an integer of 1 to 8. b represents an integer of 1 to 7.)

[0030] (In formula (2-2), c represents an integer from 1 to 7.)

[0031] (In formula (2-3), d represents an integer of 1 to 6.)

[0032] (In formula (2-4), e represents an integer of 1 to 6. e R a and R b Each independently represents a hydrogen atom or a methyl group. )

[0033] (In formula (2-5), f represents an integer from 1 to 6.)

[0034] (In formula (2-6), g represents an integer of 1 to 6.)

[0035] (In formula (2-7), g2 represents an integer from 1 to 6.)

[0036] [3] The fluorinated ether compound according to [1] or [2], wherein R in the formula (1) 1 and R 3 Each is independently a terminal group represented by the above formula (2).

[0037] [4] The fluorinated ether compound according to any one of [1] to [3], wherein R in the formula (1) 1 and R 3 same.

[0038] [5] The fluorinated ether compound according to [1] or [2], wherein R in the formula (1) 1 and R 3One of them is a terminal group represented by the above formula (2), and the other is a terminal group represented by the following formula (3) and not conforming to formula (2).

[0039]

[0040] (In formula (3), l represents an integer of 1 to 3. Each of m independently represents an integer of 1 to 6. Each of n independently represents an integer of 1 to 6. In one repeating unit, at least one of m and n is 1. B represents an alkyl group which may have only one polar group, an organic group containing a carbon-carbon unsaturated bond, or a hydrogen atom.)

[0041] [6] The fluorinated ether compound according to [1], [2] or [5], wherein R in the formula (1) 1 and R 3 One of them is a terminal group represented by the above formula (2), and the other is a terminal group represented by any one of the following formulas (3-1) to (3-3).

[0042]

[0043] (In formula (3-1), p represents an integer of 0 to 3. q represents an integer of 0 to 2. r represents an integer of 0 to 5. The total value of p and r is 1 to 5. D represents a polar group, a vinyl group, an ethynyl group, or an aryl group which may have a substituent.)

[0044] (In formula (3-2), s represents an integer from 0 to 2. t represents an integer from 1 to 5.)

[0045] (In formula (3-3), u represents an integer of 1 to 3. Five E's each independently represent a polar group, an alkoxy group having 1 to 8 carbon atoms, a halogenated group, or a hydrogen atom. When the five E's include a polar group, the number of polar groups in the five E's is 1.)

[0046] [7] The fluorinated ether compound according to any one of [1] to [6], wherein R in the formula (1) 1 and R 3 The total number of polar groups possessed is 4 to 6.

[0047] [8] The fluorinated ether compound according to any one of [1] to [7], wherein R in the formula (1) 2 It is a perfluoropolyether chain represented by the following formula (4).

[0048] -(CF2) w1 -O-(CF2O) w2 -(CF2CF2O) w3 -(CF2CF2CF2O) w4-(CF2CF2CF2CF2O) w5 -(CF2) w6 -(4)

[0049] (In formula (4), w2, w3, w4, and w5 represent average polymerization degrees, and each independently represents 0 to 20. However, w2, w3, w4, and w5 are not all 0 at the same time. w1 and w6 represent average values ​​of the number of CF2, and each independently represents 1 to 3. There is no particular limitation on the order of arrangement of (CF2O), (CF2CF2O), (CF2CF2CF2O), and (CF2CF2CF2CF2O) as repeating units in formula (4).)

[0050] [9] The fluorinated ether compound according to any one of [1] to [8], wherein R in the formula (1) 2 It is any one selected from the perfluoropolyether chains represented by the following formulae (4-1) to (4-4).

[0051] -CF2-(OCF2CF2) h -(OCF2) i -OCF2-(4-1)

[0052] (In formula (4-1), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0053] -CF2CF2-(OCF2CF2CF2) j -OCF2CF2-(4-2)

[0054] (In formula (4-2), j represents an average degree of polymerization and is 1 to 15.)

[0055] -CF2CF2CF2-(OCF2CF2CF2CF2) k -OCF2CF2CF2-(4-3)

[0056] (In formula (4-3), k represents an average degree of polymerization and is 1 to 10.)

[0057] -(CF2) w7 -O-(CF2CF2CF2O) w8 -(CF2CF2O) w9 -(CF2) w10 -(4-4)

[0058] (In formula (4-4), w8 and w9 represent average polymerization degrees, and each independently represents 1 to 20. w7 and w10 represent average values ​​of the number of CF2, and each independently represents 1 to 2.)

[0059]

[10] The fluorinated ether compound according to any one of [1] to [9], which has a number average molecular weight in the range of 500 to 10,000.

[0060]

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

[10] .

[0061]

[12] 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, wherein the lubricating layer contains the fluorine-containing ether compound described in any one of [1] to

[10] .

[0062]

[13] The magnetic recording medium according to

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

[0063] Effects of the Invention

[0064] Since the fluorine-containing ether compound of the present invention is a compound represented by the above formula (1), it is suitable as a material for a lubricant for a magnetic recording medium.

[0065] Since the lubricant for a magnetic recording medium of the present invention contains the fluorine-containing ether compound of the present invention, it is possible to form a lubricating layer which has excellent corrosion resistance and is prevented from coming off.

[0066] The magnetic recording medium of the present invention has a lubricating layer comprising a fluorine-containing ether compound of the present invention. Therefore, the magnetic recording medium of the present invention has good corrosion resistance, can suppress falling off, and has excellent reliability and durability. Therefore, the magnetic recording medium of the present invention can help reduce the magnetic spacing and can make the floating amount of the magnetic head smaller because the thickness of the lubricating layer can be made thin. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is a schematic cross-sectional view showing one embodiment of the magnetic recording medium of the present invention. DETAILED DESCRIPTION

[0068] The present inventors have conducted intensive studies in order to solve the above-mentioned problems as described below.

[0069] Conventionally, as a material for a lubricant for a magnetic recording medium (hereinafter sometimes simply referred to as “lubricant”) applied to the surface of a protective layer, a fluorine-containing ether compound having a terminal group containing a polar group such as a hydroxyl group has been preferably used.

[0070] However, when a thin lubricating layer is formed on a protective layer using a conventional fluorinated ether compound having a terminal group containing a polar group, it is difficult to realize a lubricating layer having good corrosion resistance and capable of suppressing detachment as described below.

[0071] That is, the polar groups in the fluorinated ether compound are bonded to the active points on the protective layer, thereby improving the adhesion of the lubricating layer to the protective layer. If the adhesion of the lubricating layer to the protective layer is insufficient, the coating state of the lubricating layer on the protective layer becomes insufficient, and water that causes corrosion is easily introduced into the protective layer, and sufficient corrosion resistance cannot be obtained.

[0072] In addition, the polar groups in the fluorinated ether compound not only participate in the interaction with the protective layer by combining with the active points on the protective layer, but also participate in the intramolecular and intermolecular interactions. If the polar groups participating in the intermolecular interactions between the fluorinated ether compounds are insufficient, the fluorinated ether compound in the lubricating layer is easy to scatter and fall off as the magnetic recording medium rotates.

[0073] Therefore, in order to form a lubricating layer with good corrosion resistance and suppressed detachment, the fluorinated ether compound needs to contain a sufficient number of polar groups that participate in the interaction with the protective layer and a polar group that participates in the interaction between molecules. However, if the number of polar groups in the fluorinated ether compound is increased, the hydrophobicity of the lubricating layer containing the fluorinated ether compound decreases, and thus sufficient corrosion resistance cannot be obtained.

[0074] Therefore, the inventors have repeatedly conducted in-depth studies focusing on the strength of the polar groups contained in the fluorinated ether compound and the interaction of the polar groups. As a result, it is believed that as long as at least a part of the polar groups in the fluorinated ether compound is a hydroxyl group of a 1,2-diol structure disposed at the end of the perfluoropolyether chain. In this case, as shown below, it is possible to ensure hydroxyl groups that can interact with the protective layer and hydroxyl groups that can participate in the interaction between molecules while suppressing the reduction in hydrophobicity caused by the hydroxyl groups contained in the 1,2-diol structure.

[0075] In the 1,2-diol structure (-CH(OH)-CH2OH), since the carbon atoms to which the hydroxyl groups are bonded are bonded to each other, the distance between the hydroxyl groups is close, and the steric repulsion and electrostatic repulsion between the hydroxyl groups are likely to occur. Therefore, the two hydroxyl groups included in the 1,2-diol structure are in an inverse configuration relative to the carbon atoms to which the 1,2-diol structure is bonded. Therefore, the dipole moments generated by the two hydroxyl groups included in the 1,2-diol structure cancel each other, suppressing the increase in the polarity of the entire fluorinated ether compound molecule.

[0076] In addition, the distance between the active points on the protective layer is sufficiently larger than the distance between the hydroxyl groups contained in the 1,2-diol structure. Moreover, the two hydroxyl groups contained in the 1,2-diol structure are in an inverse configuration relative to the carbon atom to which the 1,2-diol structure is bonded. Therefore, the two hydroxyl groups contained in the 1,2-diol structure are not in a direction close to the protective layer at the same time, and only one of the two hydroxyl groups can interact with the active point on the protective layer. Therefore, the other of the two hydroxyl groups can participate in the intermolecular interaction between the fluorinated ether compounds.

[0077] In addition, in the past, the structure of the fluorinated ether compound used in the lubricant was studied in order to improve the adhesion with the protective layer, so that as many polar groups as possible in the compound are arranged to easily interact with the active points on the protective layer. Therefore, since the carbon atoms to which the hydroxyl groups are bonded are bonded to each other, there is a tendency to avoid the structure in which the directions of adjacent hydroxyl groups are inversely spaced on the protective layer.

[0078] However, the present inventors have ensured that polar groups that can participate in the intermolecular interaction between the fluorinated ether compounds are present by intentionally making part of the polar groups in the fluorinated ether compound a hydroxyl group of a 1,2-diol structure. Furthermore, it is believed that the number of polar groups that can interact with the active points on the protective layer can be adjusted as needed.

[0079] Furthermore, the present inventors have repeatedly studied to improve the corrosion resistance of a lubricating layer containing a fluorinated ether compound having a 1,2-diol structure at one or both ends of a perfluoropolyether chain and to suppress the lubricating layer from peeling.

[0080] As a result, it was found that the following fluorinated ether compound can be prepared, that is, terminal groups with 1 to 4 polar groups and 1 to 50 carbon atoms are arranged at both ends of the perfluoropolyether chain, at least one of the two terminal groups is a terminal group represented by formula (2) containing at least one carbon atom that is not bonded to the polar group and the ether oxygen atom, and has a 1,2-diol structure, thereby conceiving the present invention.

[0081] For such a fluorinated ether compound, since the number of polar groups is appropriate and part of the polar groups are hydroxyl groups of a 1,2-diol structure arranged at the end of the perfluoropolyether chain, it is possible to sufficiently ensure hydroxyl groups that can interact with the protective layer and hydroxyl groups that can participate in intermolecular interactions while suppressing the reduction in hydrophobicity caused by the polar groups. Moreover, the terminal group represented by formula (2) arranged at at least one end contains at least one carbon atom that is not bound to either the polar group or the ether oxygen atom. Since the carbon atom has an extremely low affinity for water, it strongly hinders the interaction between the fluorinated ether compound molecule and water. Therefore, even if a plurality of polar groups are included in the fluorinated ether compound, sufficient hydrophobicity can be obtained. In addition, since the movement of the above-mentioned carbon atoms is suppressed, moderate rigidity is brought to the fluorinated ether compound molecule, the intramolecular interaction between the polar groups is suppressed, and it is easy for the polar groups to participate in the intermolecular interaction between the fluorinated ether compounds.

[0082] In this way, the above-mentioned fluorinated ether compound can maintain low polarity while ensuring the number of polar groups participating in the interaction with the protective layer, and has sufficient hydrophobicity. Therefore, the lubricant containing the fluorinated ether compound is not easy to introduce water that becomes the cause of corrosion, and has excellent corrosion resistance. Moreover, the above-mentioned fluorinated ether compound is easy to produce polar groups that neither participate in the interaction with the protective layer nor participate in the interaction within the molecule, and the polar groups are easy to form intermolecular interactions. Therefore, it is not easy to cause the scattering of the fluorinated ether compound accompanying the rotation of the magnetic recording medium, and a lubricating layer with excellent resistance to falling off can be formed.

[0083] On the other hand, for example, if the fluorine-containing ether compound is excessively soft, the polar groups contained in the fluorine-containing ether compound are likely to form intramolecular interactions, and thus the polar groups are unlikely to participate in intermolecular interactions.

[0084] Furthermore, when all the polar groups contained in the fluorinated ether compound are arranged such that adjacent polar groups are sufficiently far apart, all polar groups are likely to participate in the interaction with the protective layer, and the interaction between the fluorinated ether compounds due to the polar groups cannot be sufficiently achieved.

[0085] Furthermore, the present inventors have confirmed that by using a lubricant containing the above-mentioned fluorinated ether compound, a lubricating layer having excellent corrosion resistance and suppressed peeling can be formed even if the thickness is reduced, and have arrived at the present invention.

[0086] 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. The present invention is not limited to the embodiments described below.

[0087] [Fluorinated ether compounds]

[0088] The fluorine-containing ether compound of the present embodiment is represented by the following formula (1).

[0089] R 1 -CH2-R 2 -CH2-R 3 (1)

[0090] (In formula (1), R 2 R is a perfluoropolyether chain. 1 and R 3 It is a terminal group having 1 to 4 polar groups and 1 to 50 carbon atoms. 1 and R 3 They can be the same or different. 1 and R 3 At least one of them is a terminal group represented by the following formula (2).

[0091] -OX-CH(OH)-CH2OH(2)

[0092] (In formula (2), X is a divalent organic group having 2 to 30 carbon atoms which may contain at least one of 1 to 2 polar groups and 1 to 3 etheric oxygen atoms. X contains at least one carbon atom which is not bonded to either a polar group or an etheric oxygen atom.)

[0093] The fluorine-containing ether compound of this embodiment is as shown in formula (1), and for R 2 The perfluoropolyether chain (hereinafter sometimes referred to as PFPE chain) shown in FIG. 1 has R bonded to one end of the backbone via a methylene group. 1 The terminal group shown in FIG. 1 is bonded to R via a methylene group at the other end of the skeleton. 3 The terminal groups are shown.

[0094] (R 1 and R 3 terminal groups shown)

[0095] R 1 and R 3 It is a terminal group having 1 to 4 polar groups and 1 to 50 carbon atoms. 1 and R 3 At least one of them is a terminal group represented by the above formula (2).

[0096] In R 1 and R 3 When one of them is a terminal group that does not conform to formula (2), R 1 and R 3The number of polar groups contained in the terminal group that does not conform to formula (2) is 1 or more. In addition, the number of polar groups contained in the terminal group shown in formula (2) is 2 or more. Therefore, when a lubricating layer is formed on the protective layer using a lubricant containing a fluorinated ether compound, a suitable interaction occurs between the lubricating layer and the protective layer. 1 and R 3 The number of polar groups contained is preferably 2 or more. 1 and R 3 When the number of polar groups contained is 2 or more, the fluorinated ether compound can form a lubricating layer having excellent adhesion to the protective layer, and further, the intermolecular interaction between the polar groups is suitably formed, thereby preventing the lubricating layer from coming off.

[0097] R 1 and R 3 The number of polar groups contained is 4 or less. Therefore, in the lubricating layer containing the fluorine-containing ether compound, the polarity of the fluorine-containing ether compound is prevented from being too high, and the fluorine-containing ether compound agglomerates to form lumps, thereby losing the smoothness of the lubricating layer. 1 and R 3 The number of polar groups contained is preferably 3 or less. 1 and R 3 When the number of polar groups contained is 3 or less, the hydrophilicity of the fluorinated ether compound can be prevented from becoming too high to cause water to be introduced into the magnetic recording medium, which may cause corrosion, and the fluorinated ether compound can form a lubricating layer with high corrosion resistance.

[0098] R in formula (1) 1 and R 3 The total number of polar groups is preferably 3 to 6, more preferably 4 to 6. If the total number of polar groups is 3 or more, R 1 and R 3 The interaction between the polar groups possessed by the fluorinated ether compound and the protective layer. As a result, a lubricating layer having high adhesion to the protective layer can be formed. Therefore, a lubricating layer having better resistance to peeling can be obtained. In addition, if the total number of the polar groups is 6 or less, it is possible to prevent the fluorinated ether compound from being too polar and introducing water that causes corrosion. Therefore, a lubricating layer having better corrosion resistance can be formed.

[0099] R 1 and R 3 The polar groups possessed by each may be partially or entirely the same or may be different. 1 The number of polar groups and R 3The number of polar groups they have may be the same or different. In order to make the coating state of the protective layer by the fluorinated ether compound more uniform and to form a lubricating layer with better adhesion, R 1 The number of polar groups and R 3 The numbers of polar groups possessed are preferably the same.

[0100] R 1 and R 3 The polar groups contained are preferably selected from hydroxyl (-OH), carboxyl (-COOH), formyl (-(C=O)H), carbonyl (-(C=O)R 7 ; R 7 is an organic group. ), sulfonyl (-SO3H), cyano (-CN), and a group having an amide bond (-NR 8 COR 9 or-CONR 10 R 11 ; R 8 , R 9 , R 10 and R 11 Each independently is a hydrogen atom or an organic group. ), amino group (-NR 12 R 13 ; R 12 and R 13 Each independently represents a hydrogen atom or an organic group. ) is at least one polar group in the group having an amide bond. As shown in the above formula, the group having an amide bond includes both a group bonded to the carbon atom constituting the amide bond (e.g., a carbamoyl group (-C(=O)NH2)) and a group bonded to the nitrogen atom constituting the amide bond (e.g., an acetylamino group (-NHC(=O)CH3)). In the group having an amide bond, the above R 8 With R 9 can be combined with each other to form a ring, the above R 10 With R 11 The above R in the group having an amide bond may be bonded to each other to form a ring. 8 , R 9 , R 10 and R 11 Preferably, they are each independently selected from a hydrogen atom, a methyl group, an ethyl group, a propyl group, and a butyl group.

[0101] The "polar group" in this specification does not include a halogenated group (-F, -Cl, -Br, etc.) or an ether bond (-O-).

[0102] R 1 and R 3Preferably, each independently contains at least one polar group selected from a hydroxyl group, a cyano group, and a group having an amide bond. The reason is that the hydroxyl group, the cyano group, and the group having an amide bond are chemically stable, and the lubricating layer containing the fluorine-containing ether compound having these polar groups does not deteriorate for a long time. In addition, the reason is that the acidity of the hydroxyl group, the cyano group, and the group having an amide bond is not too high, and it is not easy to corrode the substrate.

[0103] R in formula (1) 1 and R 3 The polar groups preferably each contain at least one hydroxyl group. 1 and R 3 The polar groups possessed are more preferably all hydroxyl groups. The reason is that if R 1 and R 3 When all polar groups are hydroxyl groups, the coating state of the protective layer with the fluorinated ether compound becomes more uniform.

[0104] R 1 and R 3 The number of carbon atoms in the terminal group represented by is 1 to 50, preferably 3 to 20, and more preferably 4 to 15. 1 and R 3 If the number of carbon atoms in the terminal group is 1 or more, the hydrophobicity of the terminal group can be ensured, so that water that may cause corrosion can be prevented from being introduced into the lubricating layer, resulting in a lubricating layer with good corrosion resistance. 1 and R 3 When the number of carbon atoms of the terminal group is 50 or less, the terminal group has a flexible structure, and the adhesion between the lubricating layer containing the fluorinated ether compound and the protective layer becomes good. As a result, a lubricating layer that can be prevented from falling off can be obtained.

[0105] R 1 and R 3 At least one of them is a terminal group represented by the above formula (2). The terminal group represented by formula (2) has a 2 The oxygen atom (ether oxygen atom) of the methylene group (-CH2-) bonded thereto. The oxygen atom disposed at the end of the terminal group represented by formula (2) forms an ether bond (-O-) with the atoms bonded thereto on both sides. The ether bond imparts moderate softness to the fluorinated ether compound represented by formula (1), thereby increasing the affinity of the polar group possessed by the terminal group represented by formula (2) with the protective layer. Thus, the fluorinated ether compound represented by formula (1) can form a lubricating layer having excellent adhesion to the protective layer.

[0106] The terminal group represented by formula (2) has a 1,2-diol structure (-CH(OH)-CH2OH) at its terminal. Therefore, the lubricating layer containing the fluorine-containing ether compound represented by formula (1) has good corrosion resistance and can suppress peeling.

[0107] The terminal group represented by formula (2) has a divalent organic group represented by X having 2 to 30 carbon atoms. Since the organic group represented by X has 2 or more carbon atoms, it becomes moderately rigid, which can suppress intramolecular interactions and obtain sufficient hydrophobicity. In addition, since the number of carbon atoms is 30 or less, the terminal group represented by formula (2) can be suppressed from being too bulky and hindering the movement of polar groups, thereby hindering the interaction with the protective layer. The number of carbon atoms of the organic group represented by X is preferably 2 to 15, and more preferably 3 to 10.

[0108] The organic group represented by X contains at least one carbon atom that is not bonded to either the polar group or the ether oxygen atom. Examples of the carbon atom that is not bonded to either the polar group or the ether oxygen atom include a methylene group, a methine group, or a carbon atom of a fluorinated group thereof that is not bonded to either the polar group or the ether oxygen atom. In addition, as described above, the fluorine group is not included in the polar group.

[0109] When the organic group represented by X has a polar group containing carbon atoms (for example, a carboxyl group, a formyl group, a carbonyl group, a cyano group, or a group having an amide bond), the carbon atoms contained in the polar group are not included in the “carbon atoms not bonded to the polar group and the ether oxygen atom”.

[0110] The number of carbon atoms that are not bonded to polar groups and ether oxygen atoms only needs to be 1 or more, for example, it can be 1 to 6, or 1 to 4. If the number of carbon atoms that are not bonded to polar groups and ether oxygen atoms is 1 or more, the hydrophobicity of the lubricating layer containing the fluorine-containing ether compound becomes good. In addition, if the number of carbon atoms that are not bonded to polar groups and ether oxygen atoms is 6 or less, the ratio of the number of carbon atoms to the number of polar groups becomes appropriate, the polarity of the molecule becomes appropriate, and the ratio of the number of carbon atoms to the number of ether oxygen atoms becomes appropriate, and the flexibility of the molecule becomes appropriate. In addition, in the case of containing a plurality of carbon atoms that are not bonded to polar groups and ether oxygen atoms, the carbon atoms that are not bonded to polar groups and ether oxygen atoms can bond to each other. In this case, the fluorine-containing ether compound molecule becomes more rigid, the intramolecular interaction between polar groups is suppressed, and the polar groups are more likely to participate in the intermolecular interaction between fluorine-containing ether compounds.

[0111] The organic group represented by X may contain 1 or 2 polar groups. In this case, the adhesion of the fluorinated ether compound represented by formula (1) to the protective layer is improved, and it is easy to form a lubricating layer that can obtain a sufficient coating state even if the thickness is made thin. In the case where the organic group represented by X contains a polar group, the number of polar groups is preferably 1. In this case, the hydrophilicity of the fluorinated ether compound represented by formula (1) is too high to induce water that becomes the cause of corrosion.

[0112] When the organic group represented by X contains a polar group, examples of the polar group include 1and R 3 The polar group exemplified as the polar group included is more preferably a polar group selected from a hydroxyl group, a cyano group, and a group having an amide bond.

[0113] The organic group represented by X in formula (2) may contain 1 to 3 ether oxygen atoms. In this case, the ether oxygen atoms impart moderate flexibility to the fluorinated ether compound represented by formula (1), thereby increasing the affinity between the polar group and the protective layer. In the case where the organic group represented by X contains ether oxygen atoms, the number of ether oxygen atoms is preferably 1 or 2. In this case, the fluorinated ether compound represented by formula (1) can be further suppressed from being excessively flexible and causing intramolecular interactions.

[0114] The organic group represented by X in formula (2) may be partially fluorinated. In this case, the hydrophilicity of the organic group represented by X in formula (2) is reduced compared to the case of an organic group that is not fluorinated. As a result, a fluorine-containing ether compound can form a lubricating layer having good corrosion resistance and can suppress the induction of water that causes corrosion.

[0115] In formula (2), the organic group represented by X is preferably a non-cyclic organic group. When the organic group represented by X is non-cyclic, compared with the case where X has a cyclic structure, it can be suppressed that the volume is too large to hinder the movement of the polar group and hinder the interaction with the protective layer. The non-cyclic organic group can be a straight chain or a branched chain.

[0116] In formula (2), the organic group represented by X preferably does not contain an unsaturated carbon-carbon bond. In the case where the organic group represented by X does not contain an unsaturated carbon-carbon bond, compared with the case where X contains an unsaturated carbon-carbon bond, it is possible to suppress the restriction of the orientation of the molecule and hinder the movement of the polar group, thereby hindering the interaction with the protective layer.

[0117] The terminal group represented by formula (2) is preferably any one of the following formulae (2-1) to (2-7).

[0118]

[0119] (In formula (2-1), a represents an integer of 1 to 8. b represents an integer of 1 to 7.)

[0120] (In formula (2-2), c represents an integer from 1 to 7.)

[0121] (In formula (2-3), d represents an integer of 1 to 6.)

[0122] (In formula (2-4), e represents an integer of 1 to 6. e R a and R b Each independently represents a hydrogen atom or a methyl group. )

[0123] (In formula (2-5), f represents an integer from 1 to 6.)

[0124] (In formula (2-6), g represents an integer of 1 to 6.)

[0125] (In formula (2-7), g2 represents an integer from 1 to 6.)

[0126] The organic group represented by X in the formula (2) of the terminal group represented by the formula (2-1) is -CH2-CH(OH)-(CH2) a -O-(CH2) b -CH2-. a represents an integer of 1 to 8. b represents an integer of 1 to 7.

[0127] The terminal group represented by formula (2-1) has a structure in which a glycerol structure (-O-CH2-CH(OH)-CH2OH) is carbonized with b methylene groups at the terminal portion. The structure in which the glycerol structure is carbonized has moderate rigidity, and therefore can suppress the terminal group represented by formula (2-1) from forming intramolecular interactions. In addition, the ether bond possessed by the structure in which the glycerol structure is carbonized imparts moderate mobility to the terminal group represented by formula (2-1), so when one of the two hydroxyl groups at the terminal portion interacts with the protective layer, the other hydroxyl group is more likely to participate in the intermolecular interactions between the fluorinated ether compounds. Therefore, the polar groups in the fluorinated ether compound represented by formula (1) can more easily form intermolecular interactions. As a result, the lubricating layer containing the fluorinated ether compound represented by formula (1) is less likely to have the scattering of the fluorinated ether compound accompanying the rotation of the magnetic recording medium, and has better resistance to falling off.

[0128] Since a in formula (2-1) is 1 or more, the terminal group represented by formula (2-1) has sufficient hydrophobicity. In addition, since a is 8 or less, the terminal group represented by formula (2-1) will not be too bulky due to the large number of a, and the movement of the hydroxyl group in the terminal group represented by formula (2-1) can be inhibited from being hindered and hindering the interaction with the protective layer. a is preferably 1 to 6, and more preferably 1 to 4.

[0129] Since b in formula (2-1) is 1 or more, the terminal group represented by formula (2-1) has sufficient hydrophobicity. In addition, since b is 7 or less, the terminal group represented by formula (2-1) will not be too bulky due to the large number of b, and the movement of the hydroxyl group in the terminal group represented by formula (2-1) can be inhibited from being hindered and hindering the interaction with the protective layer. b is preferably 1 to 5, and more preferably 1 to 3.

[0130] The sum of a and b in formula (2-1) is preferably 9 or less. In this case, the terminal group represented by formula (2-1) will not be too bulky, and the movement of the hydroxyl group in the terminal group represented by formula (2-1) can be further inhibited from being hindered and hindering the interaction with the protective layer. The sum of a and b is more preferably 6 or less, and further preferably 4 or less.

[0131] The organic group represented by X in the formula (2) of the terminal group represented by the formula (2-2) is -CH2-CH(OH)-CH2-(CH2) c -O-CH2-. c represents an integer of 1-7.

[0132] The terminal group shown in formula (2-2) has a glycerol structure (-O-CH2-CH(OH)-CH2OH) at the terminal portion. Since the glycerol structure has high mobility, when one of the two hydroxyl groups at the terminal portion interacts with the protective layer, the other hydroxyl group is easy to interact with the polar groups in other fluorinated ether compounds between molecules. Therefore, the polar groups in the fluorinated ether compounds shown in formula (1) can more easily form intermolecular interactions. As a result, the lubricant containing the fluorinated ether compound shown in formula (1) is less likely to cause the fluorinated ether compound to fly away with the rotation of the magnetic recording medium, and has better resistance to falling off.

[0133] Since c in formula (2-2) is 1 or more, the terminal group represented by formula (2-2) has sufficient hydrophobicity. In addition, since c is 7 or less, the terminal group represented by formula (2-2) will not be too bulky due to the large number of c, and the movement of the hydroxyl group in the terminal group represented by formula (2-2) can be inhibited from being hindered and hindering the interaction with the protective layer. c is preferably 1 to 5, and more preferably 1 to 3.

[0134] The organic group represented by X in the formula (2) of the terminal group represented by the formula (2-3) is -CH2-CH(OH)-(CH2) d -. d represents an integer of 1 to 6.

[0135] The terminal group represented by formula (2-3) does not contain an ether oxygen atom as a hydrophilic part in X. Therefore, the terminal group represented by formula (2-3) has low affinity for water. Therefore, the lubricating layer containing the fluorinated ether compound represented by formula (1) is not easy to introduce water that causes corrosion, and the corrosion resistance becomes better.

[0136] The terminal group represented by formula (2-3) does not contain an ether oxygen atom in X in formula (2), and d is greater than 1, so it is moderately rigid. Therefore, the intramolecular interaction between polar groups is more effectively suppressed, and it is easier to form intermolecular interactions, so that a lubricating layer with better resistance to shedding can be formed. In addition, since d is less than 6, the terminal group represented by formula (2-3) will not be too bulky due to the large number of d, and the movement of the hydroxyl group in the terminal group represented by formula (2-3) can be suppressed from being hindered and hindering the interaction with the protective layer. d is preferably 1 to 4, and more preferably 2 to 4.

[0137] The organic group represented by X in the formula (2) of the terminal group represented by the formula (2-4) is -CH2-CH(OH)-CH2-O-CH2-(CR a R b ) e -CH2-O-CH2-. e represents an integer of 1 to 6. e R a and R b Each independently represents a hydrogen atom or a methyl group.

[0138] e -CR in the terminal group represented by formula (2-4) a R b - may be any one of -CH2-, -CH(CH3)-, and -C(CH3)2-.

[0139] In the terminal groups represented by formula (2-4), the organic group represented by X in formula (2) is a linear structure, that is, R a and R b In the case of a hydrogen atom, the terminal group volume will not be too large compared to the case where X has a branched chain. Therefore, the movement of the hydroxyl group can be inhibited from being hindered and the interaction with the protective layer can be hindered. As a result, when one of the two hydroxyl groups forming the terminal 1,2-diol structure interacts with the protective layer, the other hydroxyl group can more easily form an intermolecular interaction with the polar group in the other fluorinated ether compound. Thus, the lubricant containing the fluorinated ether compound shown in formula (1) is less likely to cause the scattering of the fluorinated ether compound accompanying the rotation of the magnetic recording medium, and has better resistance to falling off.

[0140] In the terminal group shown in formula (2-4), the organic group shown in X in formula (2) contains a branched structure, that is, in the case of -CH(CH3)- and / or -C(CH3)2-, X is moderately rigid, which can effectively suppress the intramolecular interaction between the hydroxyl groups possessed by the terminal group. Therefore, the polar group in the fluorinated ether compound shown in formula (1) can more easily form intermolecular interactions. Thus, the lubricant containing the fluorinated ether compound shown in formula (1) is less likely to cause the scattering of the fluorinated ether compound accompanying the rotation of the magnetic recording medium, and has better resistance to falling off.

[0141] Since e in formula (2-4) is 1 or more, the terminal group represented by formula (2-4) has sufficient hydrophobicity. In addition, since e is 6 or less, the terminal group represented by formula (2-4) is not too bulky, which can inhibit the movement of the hydroxyl group from being hindered and hindering the interaction with the protective layer. e is preferably 1 to 4, and more preferably 1 to 2.

[0142] The organic group represented by X in the formula (2) of the terminal group represented by the formula (2-5) is -CH2-CH(OH)-CH2-O-CH2-(CF2) f -CH2-O-CH2-. f represents an integer of 1 to 6.

[0143] The terminal group represented by formula (2-5) contains a linear perfluoroalkylene chain having 1 to 6 carbon atoms which reduces affinity with water. In the case of having a terminal group represented by formula (2-5), a saturated hydrocarbon group containing a perfluoroalkylene chain (-CH2-(CF2) in formula (2-5) f -CH2-) reduces the polarity of the entire molecule and improves hydrophobicity. As a result, the affinity of the fluorinated ether compound to water, which is a cause of corrosion, is reduced. As a result, the lubricating layer containing the fluorinated ether compound represented by formula (1) suppresses the introduction of water, which is a cause of corrosion, and has better corrosion resistance.

[0144] Since f in formula (2-5) is 1 or more, the terminal group shown in formula (2-5) becomes moderately rigid, which can suppress the intramolecular interaction. In addition, since f is 6 or less, the terminal group shown in formula (2-5) is not too bulky, which can suppress the movement of the hydroxyl group from being hindered and hindering the interaction with the protective layer. f in formula (2-5) is preferably 1 to 4, and more preferably 2 to 4.

[0145] The organic group represented by X in the formula (2) of the terminal group represented by the formula (2-6) is -(CH2) g -CH2-. g represents an integer of 1 to 6.

[0146] The terminal group represented by formula (2-6) does not contain a polar group and an ether oxygen atom as a hydrophilic part in X. Therefore, the terminal group represented by formula (2-6) has a low affinity for water. Therefore, the lubricating layer containing the fluorinated ether compound represented by formula (1) is not easy to introduce water that causes corrosion, and the corrosion resistance becomes better.

[0147] Since g in formula (2-6) is 1 or more, formula (2-6) becomes moderately rigid, and the hydroxyl groups in the 1,2-diol structure are not easy to form intramolecular interactions. In addition, since g in formula (2-6) is 6 or less, the terminal group shown in formula (2-6) is not too bulky, and the movement of the hydroxyl groups can be inhibited from being hindered and the interaction with the protective layer can be inhibited. g is preferably 1 to 5, and more preferably 1 to 3.

[0148] The organic group represented by X in the formula (2) of the terminal group represented by the formula (2-7) is -(CH2) g2 -CH2-CH(OH)-CH2-O-CH2-. g2 represents an integer of 1 to 6.

[0149] The terminal group shown in formula (2-7) has a glycerol structure (-O-CH2-CH(OH)-CH2OH) at the terminal portion. Since the glycerol structure has high mobility, when one of the two hydroxyl groups at the terminal portion interacts with the protective layer, the other hydroxyl group is easy to interact with the polar groups in other fluorinated ether compounds between molecules. Therefore, the polar groups in the fluorinated ether compounds shown in formula (1) can more easily form intermolecular interactions. As a result, the lubricant containing the fluorinated ether compound shown in formula (1) is less likely to cause the fluorinated ether compound to fly away with the rotation of the magnetic recording medium, and has better resistance to falling off.

[0150] Since g2 in formula (2-7) is 1 or more, formula (2-7) becomes moderately rigid, and the hydroxyl groups in the 1,2-diol structure are not easy to form intramolecular interactions. In addition, since g2 in formula (2-7) is 6 or less, the terminal group volume shown in formula (2-7) is not too large, which can prevent the movement of the hydroxyl groups from being hindered and hindering the interaction with the protective layer. g2 is preferably 1 to 5, and more preferably 1 to 3.

[0151] Among the terminal groups represented by formulae (2-1) to (2-7), the terminal groups represented by formulae (2-3), (2-5), and (2-6) have better corrosion resistance.

[0152] Among the terminal groups represented by formulas (2-1) to (2-7), the terminal groups represented by formulas (2-1), (2-2), (2-4), and (2-7) have better resistance to falling off when the sum of a and b in formula (2-1) is less than 4, c in formula (2-2) is less than 3, e in formula (2-4) is less than 2, and g2 in formula (2-7) is less than 3.

[0153] In the fluorine-containing ether compound represented by formula (1), R 1 With R 3 Can be the same or different. 1 and R 3In this case, the fluorine-containing ether compound can be easily and efficiently produced. 1 With R 3 Same” means R 1 The atoms contained in R 3 The atoms included are relative to -CH2-R 2 -CH2- and are symmetrically arranged.

[0154] In the fluorine-containing ether compound represented by formula (1), R 1 With R 3 In different situations, you can 1 and R 3 Each independently represents a terminal group represented by formula (2), and R 1 and R 3 One of them is a terminal group represented by formula (2), and the other is a terminal group not conforming to formula (2). The terminal group not conforming to formula (2) may be a terminal group having 1 to 4 polar groups and 1 to 50 carbon atoms as described above.

[0155] In R 1 and R 3 When one of them is a terminal group represented by formula (2) and the other is a terminal group not conforming to formula (2), the terminal group not conforming to formula (2) is preferably represented by the following formula (3).

[0156]

[0157] (In formula (3), l represents an integer of 1 to 3. Each of m independently represents an integer of 1 to 6. Each of n independently represents an integer of 1 to 6. In one repeating unit, at least one of m and n is 1. B represents an alkyl group which may have only one polar group, an organic group containing a carbon-carbon unsaturated bond, or a hydrogen atom.)

[0158] The terminal group represented by formula (3) has a 2 The oxygen atom (ether oxygen atom) of the methylene group (-CH2-) bonded to the terminal group represented by formula (3) forms an ether bond (-O-) with the atoms bonded to both sides thereof. The ether bond imparts moderate softness to the fluorinated ether compound represented by formula (1), thereby increasing the affinity of the polar group possessed by the terminal group represented by formula (3) with the protective layer. Thus, the fluorinated ether compound represented by formula (1) can form a lubricating layer having excellent adhesion to the protective layer.

[0159] In formula (3), l is an integer of 1 to 3, preferably an integer of 1 to 2, and more preferably 1. When l in formula (3) is 3 or less, water that may cause corrosion due to excessive hydroxyl groups of the terminal groups represented by formula (3) can be prevented from being introduced into the lubricating layer, and a lubricating layer having good corrosion resistance can be obtained.

[0160] When l in formula (3) is 2 or 3, 2 or 3 repeating units (-(CH2) m -CH(OH)-(CH2) n The combinations of m and n in (-O-) may be different from each other, or may be partially or entirely the same.

[0161] Each of the m in formula (3) independently represents an integer of 1 to 6. Each of the n independently represents an integer of 1 to 6. In formula (3), one repeating unit (-(CH2) m -CH(OH)-(CH2) n -O-), at least one of m and n is 1. In this case, the mobility of the hydroxyl group in the repeating unit can be prevented from being reduced due to the excessive number of carbon atoms in the alkylene group between the carbon atom bonded via the hydroxyl group and the ether oxygen atom.

[0162] B in formula (3) represents an alkyl group which may have only one polar group, an organic group containing a carbon-carbon unsaturated bond, or a hydrogen atom.

[0163] When B in the formula (3) is an alkyl group having no polar group, examples of B include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.

[0164] When B in formula (3) is an alkyl group having a polar group, the polar group is preferably 1 and R 3 The polar groups mentioned above are preferred examples of the polar groups contained. Among the above polar groups, more preferred are polar groups selected from the group consisting of a hydroxyl group, a cyano group, and a group having an amide bond.

[0165] When B in formula (3) is an alkyl group having a polar group, examples of B include 2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl, 5-hydroxypentyl, 6-hydroxyhexyl, 2-aminoethyl, 3-aminopropyl, 1-carboxymethyl, 2-carboxyethyl, 3-carboxypropyl, 1-carbonylmethyl, 2-carbonylethyl, 3-carbonylpropyl, 1-acetylmethyl, 2-acetylethyl, 3-acetylpropyl, 2-sulfoethyl, 3-sulfopropyl, 1-cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 4-cyanobutyl, 2-acetylaminoethyl, 3-acetylaminopropyl, 4-acetylaminobutyl, 1-carbamoylmethyl, 2-carbamoylethyl, 3-carbamoylpropyl, and 4-carbamoylbutyl.

[0166] Among the above-mentioned alkyl groups having a polar group, any one of 2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl, 5-hydroxypentyl, 6-hydroxyhexyl, 1-cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 2-acetylaminoethyl, 1-carbamoylmethyl, 2-carbamoylethyl, and 3-carbamoylpropyl is preferred, and any one of 2-hydroxyethyl, 3-hydroxypropyl, 2-cyanoethyl, 3-cyanopropyl, 2-acetylaminoethyl, and 1-carbamoylmethyl is more preferred.

[0167] When B in formula (3) is an organic group containing a carbon-carbon unsaturated bond, examples of B include organic groups containing at least one selected from aromatic hydrocarbons, unsaturated heterocycles, alkenyl groups, and alkynyl groups.

[0168] In the case where B in the formula (3) is an organic group containing a carbon-carbon unsaturated bond, examples of B include phenyl, methoxyphenyl, fluorophenyl, acetylaminophenyl, carbamoylphenyl, cyanophenyl, naphthyl, phenethyl, methoxyphenethyl, fluorophenethyl, benzyl, methoxybenzyl, naphthylmethyl, methoxynaphthyl, pyrrolyl, pyrazolyl, methylpyrazolylmethyl, imidazolyl, furanyl, furfuryl, Azolyl, iso oxazolyl, thienyl, thienylethyl, thiazolyl, methylthiazolylethyl, isothiazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, indolinyl, benzofuranyl, benzothienyl, benzimidazolyl, benzo Azolyl, benzothiazolyl, benzopyrazolyl, benzisophthalic acid oxazolyl, benzisothiazolyl, quinolyl, isoquinolyl, quinazolinyl, quinoxalinyl, phthalazinyl, cinnolinyl, vinyl, allyl, butenyl, propynyl, propargyl, butynyl, methylbutynyl, pentynyl, methylpentynyl, hexynyl and the like.

[0169] Among the organic groups containing carbon-carbon unsaturated bonds, preferably any one of phenyl, methoxyphenyl, acetylaminophenyl, carbamoylphenyl, cyanophenyl, naphthyl, phenethyl, methoxyphenethyl, fluorophenethyl, thienylethyl, allyl, butenyl, and propargyl is preferred, and particularly preferably any one of phenyl, methoxyphenyl, carbamoylphenyl, allyl, and butenyl is more preferred. In this case, the terminal group represented by formula (3) has sufficient hydrophobicity and is not too large in volume, so that the movement of the hydroxyl group in formula (3) can be inhibited and the interaction with the protective layer can be inhibited.

[0170] When B in formula (3) is a hydrogen atom, B forms a hydroxyl group together with the oxygen atom in formula (3).

[0171] The terminal group represented by formula (3) is more preferably represented by any one of the following formulae (3-1) to (3-3).

[0172]

[0173] (In formula (3-1), p represents an integer of 0 to 3. q represents an integer of 0 to 2. r represents an integer of 0 to 5. The total value of p and r is 1 to 5. D represents a polar group, a vinyl group, an ethynyl group, or an aryl group which may have a substituent.)

[0174] (In formula (3-2), s represents an integer from 0 to 2. t represents an integer from 1 to 5.)

[0175] (In formula (3-3), u represents an integer of 1 to 3. Five E's each independently represent a polar group, an alkoxy group having 1 to 8 carbon atoms, a halogenated group, or a hydrogen atom. When the five E's include a polar group, the number of polar groups in the five E's is 1.)

[0176] For the terminal groups shown in formulas (3-1) to (3-3), each polar group contained in the terminal group is bonded to a different carbon atom. In addition, the carbon atoms bonded to the polar groups are bonded to each other via a linking group containing a carbon atom not bonded to the polar group. Therefore, the terminal groups shown in formulas (3-1) to (3-3) can be oriented so that both the terminal polar group and the hydroxyl group adjacent to the terminal polar group can be closely attached to the protective layer through a linking group containing a carbon atom not bonded to the polar group. Therefore, a lubricating layer that obtains a strong interaction with the protective layer can be formed.

[0177] Compared with terminal groups in which carbon atoms bonded to polar groups are directly bonded to each other, polar groups in terminal groups represented by formulas (3-1) to (3-3) are less likely to aggregate with each other and are more likely to interact with the protective layer. Therefore, the terminal portion in the fluorinated ether compound represented by the terminal groups represented by formulas (3-1) to (3-3) is less likely to float and the adhesion with the protective layer is less likely to decrease.

[0178] The linking group between the carbon atom to which D of the terminal group represented by formula (3-1) is bonded and the carbon atom to which the hydroxyl group adjacent to D at the terminal is bonded contains an ether oxygen atom. The linking group has a linear structure consisting of 2 to 7 atoms including a carbon atom to which no polar group is bonded.

[0179] The above-mentioned connecting group of the terminal group shown in formula (3-1) is a straight-chain structure consisting of two or more atoms including carbon atoms not bonded to polar groups. Therefore, the distance between D and the hydroxyl group adjacent to D is appropriate. Therefore, since it is possible to suppress the interaction between D and the hydroxyl group adjacent to D in the molecule, the polar group can be tightly fitted to the protective layer efficiently. Further, since the terminal group shown in formula (3-1) is the above-mentioned structure, even if it contains ether oxygen atoms, a fluorine-containing ether compound with good hydrophobicity can be obtained. In addition, the mobility of the molecule is appropriate, intramolecular agglomeration is not easy to occur, and it has excellent tightness with the protective layer.

[0180] The connecting group of the terminal group represented by formula (3-1) is a linear structure consisting of 7 or less atoms including an ether oxygen atom and a carbon atom not bonded to a polar group. Therefore, the high hydrophobicity of the connecting group does not hinder the adhesion between the lubricating layer containing the fluorinated ether compound and the protective layer.

[0181] Based on these facts, the fluorine-containing ether compound having a terminal group represented by formula (3-1) can form a lubricating layer which has excellent adhesion to the protective layer, exhibits high corrosion resistance, and can be suppressed from falling off.

[0182] In the terminal group represented by formula (3-1), the total value of p and r is 1 to 5, preferably 1 to 3. The terminal group represented by formula (3-1) has a linking group between the carbon atom to which D is bonded and the carbon atom to which the hydroxyl group adjacent to D disposed at the terminal is bonded. The carbon atoms contained in the above-mentioned linking group prevent the intramolecular interaction between the adjacent polar groups from occurring in priority to the interaction between the polar groups and the protective layer. Thus, the carbon atoms contained in the above-mentioned linking group improve the adhesion between the polar groups in formula (3-1) and the protective layer.

[0183] If the above-mentioned connecting group contains too many carbon atoms, the flexibility of the terminal group represented by formula (3-1) is sometimes reduced, and it is difficult to evenly cover the entire surface of the protective layer. For the terminal group represented by formula (3-1), since the total value of p and r is less than 5, the alkylene chain of the main chain part of formula (3-1) will not be too long. Therefore, it is possible to prevent the flexibility of the terminal part from being reduced due to the rigid alkylene chain length, and the interaction with the protective layer from being weakened, causing the terminal part to float up. p is an integer of 0 to 3, preferably 0 or 1, and more preferably 0. r is an integer of 0 to 5, preferably 1 or 2, and more preferably 1.

[0184] In formula (3-1), D represents a polar group, a vinyl group, an ethynyl group, or an aryl group which may have a substituent. When D is a polar group, D is preferably R 1 and R 3The groups are listed as preferred examples of polar groups included in the above-mentioned polar groups. Among the above-mentioned polar groups, more preferred are polar groups selected from hydroxyl groups, cyano groups, and groups having amide bonds. When D is an aryl group which may have a substituent, an aryl group which may have a substituent and is included in the organic group which can be used when B in the above-mentioned formula (3) is an organic group containing a carbon-carbon unsaturated bond can be used.

[0185] In formula (3-1), q represents an integer of 0 to 2. The number of polar groups in formula (3-1) is q+2 when D is a polar group, and is q+1 when D is a vinyl group or an ethynyl group. As described above, R 1 and R 3 The number of polar groups contained is preferably 2 or 3. Therefore, q in formula (3-1) is preferably 0 or 1 when D is a polar group, and is preferably 1 or 2 when D is a vinyl group or an ethynyl group. When D is an aryl group which may have a substituent, q is preferably selected so that the number of polar groups in formula (3-1) becomes 2 or 3.

[0186] The connecting group between the carbon atom bonded to the terminal hydroxyl group of the terminal group represented by formula (3-2) and the carbon atom bonded to the hydroxyl group adjacent to the terminal hydroxyl group does not contain an oxygen atom. Therefore, the intramolecular interaction is small and intramolecular aggregation is not likely to occur, so it has excellent adhesion to the protective layer.

[0187] The above-mentioned linking group of the terminal group shown in formula (3-2) is a linear structure composed of 1 to 5 atoms of carbon atoms containing unbound hydroxyl groups. Since the above-mentioned linking group is a linear structure composed of one or more atoms of carbon atoms containing unbound hydroxyl groups, the distance between the terminal hydroxyl group and the hydroxyl group adjacent to the terminal hydroxyl group is appropriate. Therefore, intramolecular aggregation is not likely to occur, and a fluorinated ether compound with good hydrophobicity can be obtained.

[0188] The above-mentioned connecting group of the terminal group shown in formula (3-2) is a linear structure consisting of 5 or less atoms including carbon atoms not bonded to hydroxyl groups and not containing oxygen atoms. Therefore, the hydrophobicity of the connecting group is too high to hinder the adhesion with the protective layer, and the connection group is too large to hinder the movement of the hydroxyl group.

[0189] In the terminal group represented by formula (3-2), t is an integer of 1 to 5. For the terminal group represented by formula (3-2), similarly to the terminal group represented by formula (3-1), if the carbon atoms contained in the connecting group arranged between the carbon atoms bonded to the polar group are too many, the flexibility of the terminal group represented by formula (3-2) is sometimes reduced, and it is difficult to evenly cover the entire surface of the protective layer. For the terminal group represented by formula (3-2), since t is less than 5, the alkylene chain of the main chain part of formula (3-2) will not be too long. Therefore, it is possible to prevent the flexibility of the terminal part from being reduced due to the length of the rigid alkylene chain, and the interaction between the terminal hydroxyl group and the protective layer from being reduced. t is preferably 1 or 2, and more preferably 1.

[0190] According to these circumstances, the fluorine-containing ether compound having an end group represented by formula (3-2) can form a lubricating layer that has excellent adhesion to the protective layer, high corrosion resistance, and can inhibit shedding, because the above-mentioned connecting group in formula (3-2) does not contain an oxygen atom and has a straight-chain structure composed of 1 to 5 atoms containing carbon atoms that are not bound to a hydroxyl group.

[0191] In formula (3-2), s represents an integer of 0 to 2. The number of polar groups in formula (3-2) is s+2. As described above, R 1 and R 3 The number of polar groups contained is preferably 2 or 3. Therefore, s in formula (3-2) is preferably 0 or 1.

[0192] In the terminal group represented by formula (3-3), five E's each independently represent a polar group, an alkoxy group having 1 to 8 carbon atoms, a halogenated group, or a hydrogen atom. When the five E's include a polar group, the number of polar groups in the five E's is one.

[0193] In the terminal group represented by formula (3-3), when a polar group is included in 5 E's, the linking group between the carbon atom to which the polar group represented by E is bound and the carbon atom to which the hydroxyl group adjacent to the polar group represented by E is bound contains an oxygen atom forming an ether bond. The above-mentioned linking group has a structure consisting of 3 to 5 atoms including carbon atoms to which the polar group is not bound. The number of atoms of the above-mentioned linking group refers to the number of atoms of the shortest distance between the carbon atom to which the polar group included by E is bound and the carbon atom to which the hydroxyl group adjacent to the polar group included by E is bound.

[0194] In the terminal group shown in formula (3-3), when a polar group is included in 5 E, the above-mentioned connecting group is a structure consisting of 3 or more atoms including an oxygen atom forming an ether bond and a carbon atom not combined with a polar group. Therefore, the distance between the polar group shown in E and the hydroxyl group adjacent to the polar group shown in E is appropriate. In addition, since the benzene ring is rigid, it is difficult to rotate freely. Therefore, the polar group shown in E as a substituent combined with the benzene ring and the hydroxyl group adjacent to the polar group shown in E can be suppressed from interacting.

[0195] u in formula (3-3) represents an integer of 1 to 3. When u in formula (3-3) is 2 or 3, -(CH2CH(OH)CH2O) u - The linking group between the carbon atoms to which the adjacent multiple hydroxyl groups are bonded has a linear structure consisting of three atoms including an oxygen atom forming an ether bond and a carbon atom not bonded to a hydroxyl group. Since the linking group is a linear structure consisting of three atoms including a carbon atom not bonded to a hydroxyl group, the distance between adjacent hydroxyl groups is appropriate. Therefore, the interaction between hydroxyl groups in the molecule can be suppressed.

[0196] According to these conditions, for the fluorinated ether compound having the terminal group represented by formula (3-3), the interaction between polar groups in the molecule can be suppressed. Therefore, the lubricating layer containing the fluorinated ether compound having the terminal group represented by formula (3-3) has excellent adhesion to the protective layer and good fall-off suppression effect.

[0197] In the terminal group represented by formula (3-3), when no polar group is included among the 5 E's, the hydrophobicity of the molecule becomes higher than when one of the 5 E's is a polar group. Therefore, the lubricating layer containing the fluorinated ether compound having the terminal group represented by formula (3-3) can further suppress the induction of water that causes corrosion, and has higher corrosion resistance.

[0198] In the terminal group represented by formula (3-3), when E is a polar group, E is preferably R 1 and R 3 Polar groups are listed as preferred examples of polar groups contained therein. Among the above polar groups, E is more preferably a polar group selected from a cyano group and a group having an amide bond, and is further preferably a cyano group, an acetylamino group (-NHC(=O)CH3) or a carbamoyl group (-C(=O)NH2). The reason is that if the polar group is a cyano group, an acetylamino group or a carbamoyl group, it becomes a fluorine-containing ether compound that can form a lubricating layer that interacts more firmly with the protective layer. In addition, the reason is that since the acidity of the cyano group, the acetylamino group or the carbamoyl group is not too high, the fluorine-containing ether compound containing them has almost no effect of corroding the substrate. In the case where E is not a polar group, it is preferably each independently a methoxy group, a fluoro group or a hydrogen atom.

[0199] The number of polar groups in formula (3-3) is u+1 when the five E's contain a polar group, and is u when the five E's do not contain a polar group. As described above, R 1 and R 3 The number of polar groups contained is preferably 2 or 3. Therefore, u in formula (3-3) is preferably 1 or 2 when the 5 E's contain a polar group, and is preferably 2 or 3 when the 5 E's do not contain a polar group.

[0200] In the case where the 5 E's in formula (3-3) contain a polar group, the 4 E's other than the polar group may be partially or entirely the same, or may be different from each other. In the case where the 5 E's contain a polar group, the 4 E's other than the polar group are preferably all the same. In the case where the 5 E's do not contain a polar group, the 5 E's may be partially or entirely the same, or may be different from each other.

[0201] When the five E's in formula (3-3) contain a polar group, the position of the polar group may be any position among the five E's.

[0202] (R 2 PFPE chain shown)

[0203] In the fluorine-containing ether compound represented by formula (1), R 2 When a lubricant containing the fluorinated ether compound of this embodiment is applied onto the protective layer to form a lubricating layer, R 2 The PFPE chains shown 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. 2 The PFPE chain shown is appropriately selected depending on the performance required of the lubricant containing the fluorine-containing ether compound, etc.

[0204] As R 2 The PFPE chain shown in the figure may be a PFPE chain formed by a polymer or copolymer of a perfluoroalkylene oxide compound, etc. Examples of the perfluoroalkylene oxide compound include perfluoromethylene oxide compounds, perfluoroethylene oxide compounds, perfluoro-n-propylene oxide compounds, perfluoro-isopropylene oxide compounds, and perfluorobutylene oxide compounds.

[0205] R in formula (1) 2 For example, a PFPE chain represented by the following formula (4) derived from a polymer or copolymer of a perfluoroalkylene oxide compound is preferred.

[0206] -(CF2) w1 -O-(CF2O) w2 -(CF2CF2O) w3 -(CF2CF2CF2O)w4 -(CF2CF2CF2CF2O) w5 -(CF2) w6 -(4)

[0207] (In formula (4), w2, w3, w4, and w5 represent average polymerization degrees, and each independently represents 0 to 20. However, w2, w3, w4, and w5 are not all 0 at the same time. w1 and w6 represent average values ​​of the number of CF2, and each independently represents 1 to 3. There is no particular limitation on the order of arrangement of (CF2O), (CF2CF2O), (CF2CF2CF2O), and (CF2CF2CF2CF2O) as repeating units in formula (4).)

[0208] In formula (4), w2, w3, w4, and w5 represent average polymerization degrees, and are each independently 0 to 20, preferably 0 to 15, and more preferably 0 to 10.

[0209] In formula (4), w1 and w6 are average values ​​representing the number of CF2, and each independently represents 1 to 3. In the PFPE chain represented by formula (4), w1 and w6 are determined by the structure of the repeating unit arranged at the end of the chain structure, etc.

[0210] In formula (4), (CF2O), (CF2CF2CF2O), (CF2CF2CF2O), (CF2CF2CF2CF2O) are repeating units. There is no particular restriction on the arrangement order of the repeating units in formula (4). In addition, there is no particular restriction on the number of types of repeating units in formula (4).

[0211] R in formula (1) 2 It is preferably any one selected from the PFPE chains represented by the following formulae (4-1) to (4-4).

[0212] -CF2-(OCF2CF2) h -(OCF2) i -OCF2-(4-1)

[0213] (In formula (4-1), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0214] -CF2CF2-(OCF2CF2CF2) j -OCF2CF2-(4-2)

[0215] (In formula (4-2), j represents the average degree of polymerization and is 1 to 15.)

[0216] -CF2CF2CF2-(OCF2CF2CF2CF2) k-OCF2CF2CF2-(4-3)

[0217] (In formula (4-3), k represents the average degree of polymerization and is 1 to 10.)

[0218] -(CF2) w7 -O-(CF2CF2CF2O) w8 -(CF2CF2O) w9 -(CF2) w10 -(4-4)

[0219] (In formula (4-4), w8 and w9 represent average polymerization degrees, and each independently represents 1 to 20. w7 and w10 represent average values ​​of the number of CF2, and each independently represents 1 to 2.)

[0220] If R 2 is any one of the PFPE chains represented by formulas (4-1) to (4-4), a fluorine-containing ether compound can be used to obtain a lubricating layer having good lubricity. 2 In the case of any one of the PFPE chains represented by formulas (4-1) to (4-4), the ratio of the number of oxygen atoms (the number of ether bonds (-O-)) in the PFPE chain to the number of carbon atoms is appropriate. Therefore, it becomes a fluorine-containing ether compound having a moderate hardness. Therefore, the fluorine-containing ether compound coated on the protective layer is not easy to agglomerate on the protective layer, and a thinner lubricating layer can be formed with a sufficient coverage. In addition, R 2 A lubricating layer containing a fluorinated ether compound selected from the PFPE chains represented by formulae (4-1) to (4-4) is more dense and can be more inhibited from falling off, and is therefore preferred.

[0221] In formula (4-1), there is no particular restriction on the arrangement order of (OCF2CF2) and (OCF2) as repeating units. In formula (4-1), the number h of (OCF2CF2) and the number i of (OCF2) may be the same or different. The PFPE chain shown in formula (4-1) may be a polymer of (OCF2CF2). In addition, the PFPE chain shown in formula (4-1) may be any of a random copolymer, a block copolymer, and an alternating copolymer composed of (OCF2CF2) and (OCF2).

[0222] In formulas (4-1) to (4-3), since 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, it is a fluorine-containing ether compound that can obtain a lubricating layer with good lubricity. In addition, in formulas (4-1) to (4-3), since 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, the viscosity of the fluorine-containing ether compound does not become too high, and the lubricant containing the fluorine-containing ether compound is easy to apply and is preferred. In order to obtain a fluorine-containing ether compound that is easy to wet and spread on the protective layer and easy to obtain a lubricating layer with 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 further preferably 2 to 7.

[0223] In formula (4-4), there is no particular restriction on the arrangement order of (CF2CF2CF2O) and (CF2CF2O) as repeating units. In formula (4-4), the number w8 of (CF2CF2CF2O) representing the average degree of polymerization and the number w9 of (CF2CF2O) may be the same or different. Formula (4-4) may include any of a random copolymer, a block copolymer, and an alternating copolymer composed of monomer units (CF2CF2CF2O) and (CF2CF2O).

[0224] In formula (4-4), w8 and w9 representing the average degree of polymerization are preferably 1 to 20, 1 to 15, and more preferably 1 to 10, each independently.

[0225] w7 and w10 in formula (4-4) are average values ​​representing the number of CF2, and each independently represents 1 to 2. In the PFPE chain represented by formula (4-4), w7 and w10 are determined by the structure of the repeating unit arranged at the end of the chain structure, etc.

[0226] The fluorine-containing ether compound represented by formula (1) is preferably any one of the compounds represented by the following formulas (AA) to (AS), (BA) to (BH), (CA) to (CK). When the compound represented by formula (1) is any one of the compounds represented by the following formulas (AA) to (AS), (BA) to (BH), (CA) to (CK), the raw material is easy to obtain, and a lubricating layer can be formed that has better corrosion resistance and can suppress shedding even if the thickness is thin.

[0227] In the compounds represented by the following formulas (AA) to (AS), (BA) to (BH), (CA) to (CK), Rf1, Rf2, and Rf3 representing a PFPE chain each have the following structure. That is, in the compounds represented by the following formulas (AA) to (AS), (BA) to (BF), (CA), (CB), and (CE), Rf1 is the PFPE chain represented by the above formula (4-1). In the compounds represented by the following formulas (BG), (CC), (CF) to (CK), Rf2 is the PFPE chain represented by the above formula (4-2). In the compounds represented by the following formulas (BH) and (CD), Rf3 is the PFPE chain represented by the above formula (4-3). In addition, h and i in Rf1 representing a PFPE chain in the formulas (AA) to (AS), (BA) to (BH), (CA) to (CK), j in Rf2, and k in Rf3 are not necessarily integers because they are values ​​representing the average degree of polymerization.

[0228]

[0229] In the compounds represented by the following formulas (AA) to (AS), R in formula (1) is 1 and R 3 is a terminal group represented by any one of the above formulae (2-1) to (2-6). 2 It is the PFPE chain represented by the above formula (4-1).

[0230] In the compounds represented by the following formulas (BA) to (BE), R in formula (1) is 1 and R 3 One of them is a terminal group represented by the above formula (2-1), and the other is a terminal group represented by any one of the above formulas (3-1) and (3-2). 2 It is the PFPE chain represented by the above formula (4-1).

[0231] In the compound represented by the following formula (BF), R in the formula (1) is 1 and R 3 One of them is the terminal group represented by the above formula (2-1), and the other is the terminal group represented by the formula (3). 2 The terminal group represented by the formula (3) does not correspond to any of the formulas (3-1) to (3-3).

[0232] In the compounds represented by the following formulas (BG) and (BH), R in formula (1) is 1 and R 3 is the terminal group represented by the above formula (2-1). 2 It is a PFPE chain represented by the above formula (4-2) or (4-3).

[0233]

[0234] (In Rf1 in formula (AA), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0235] (In Rf1 in formula (AB), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0236] (In Rf1 in formula (AC), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0237] (In Rf1 in formula (AD), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0238]

[0239] (In Rf1 in formula (AE), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (AF), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (AG), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (AH), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0240]

[0241] (In Rf1 in formula (AI), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (AJ), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (AK), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (AL), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0242]

[0243] (In Rf1 in formula (AM), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (AN), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (AO), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (AP), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0244]

[0245] (In Rf1 in formula (AQ), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (AR), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.) (In Rf1 in formula (AS), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0246]

[0247] (In Rf1 in formula (BA), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0248] (In Rf1 in formula (BB), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0249] (In Rf1 in formula (BC), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0250] (In Rf1 in formula (BD), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0251]

[0252] (In Rf1 in formula (BE), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0253] (In Rf1 in formula (BF), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.)

[0254] (In Rf2 in formula (BG), j represents the average degree of polymerization and is 1 to 15.)

[0255] (In Rf3 in formula (BH), k represents the average degree of polymerization and is 1 to 10.)

[0256] In the compounds represented by the following formulas (CA) to (CK), R in formula (1) is 1 and R 3 is a terminal group represented by any one of the above formulae (2-1) to (2-7). 2 It is a PFPE chain represented by any one of the above formulas (4-1) to (4-3).

[0257]

[0258] (In Rf1 in formula (CA), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0.) (In Rf1 in formula (CB), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0.) (In Rf2 in formula (CC), j represents average polymerization degree, and represents 1 to 15.)

[0259] (In Rf3 in formula (CD), k represents the average degree of polymerization and is 1 to 10.)

[0260] (In Rf1 in formula (CE), h and i represent average polymerization degrees, h represents 1 to 20, and i represents 0 to 20.) (In Rf2 in formula (CF), j represents average polymerization degree, and represents 1 to 15.)

[0261] (In Rf2 in formula (CG), j represents the average degree of polymerization and is 1 to 15.)

[0262] (In Rf2 in the formula (CH), j represents the average degree of polymerization and is 1 to 15.)

[0263] (In Rf2 in formula (CI), j represents the average degree of polymerization and is 1 to 15.)

[0264] (In Rf2 in formula (CJ), j represents the average degree of polymerization and is 1 to 15.)

[0265] (In Rf2 in formula (CK), j represents the average degree of polymerization and is 1 to 15.)

[0266] 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 formed by 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 is appropriate, and a lubricating layer with a thin film thickness can be easily formed by applying the lubricant containing the fluorinated ether compound. 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.

[0267] The number average molecular weight (Mn) of the fluorinated ether compound was determined by using AVANCE III 400 manufactured by Bruker Biospin Co., Ltd. 1 H-NMR and 19 Specifically, the value measured by 19The number of repeating units of the PFPE chain was calculated from the integrated value measured by F-NMR to determine the number average molecular weight. In the measurement of NMR (nuclear magnetic resonance), the sample was diluted in a hexafluorobenzene / d-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 set at 2.2 ppm based on the peak of acetone.

[0268] The fluorinated ether compound of the present embodiment is preferably subjected to molecular weight fractionation by an appropriate method so that the molecular weight dispersion (weight average molecular weight (Mw) / number average molecular weight (Mn) ratio) is less than 1.3. In the present embodiment, there is no particular restriction on the method for conducting molecular weight fractionation, and for example, molecular weight fractionation using silica gel column chromatography, gel permeation chromatography (GPC) method, molecular weight fractionation using supercritical extraction method, etc. can be used.

[0269] "Manufacturing method"

[0270] The method for producing the fluorine-containing ether compound of the present embodiment is not particularly limited, and the fluorine-containing ether compound of the present embodiment 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 production method described below.

[0271] (R 1 With R 3 Same situation)

[0272] In formula (1), in order to make R 1 With R 3 The same compound is first prepared in the same manner as R in formula (1) 2 The corresponding perfluoropolyether chain has fluorine compounds having hydroxymethyl groups (-CH2OH) at both ends.

[0273] Next, the hydroxyl groups of the hydroxymethyl groups disposed at both ends of the fluorine-based compound are reacted with the hydroxyl groups of the hydroxymethyl groups having the formula (1) as R 1 The group (= becomes R 3 Thus, the epoxy group of the epoxy compound with R 2 The two ends of the corresponding perfluoropolyether chain have 1 The corresponding group (= with R 3 The corresponding group) of the compound.

[0274] As R in formula (1) 1 The group (= becomes R 3 As the epoxy compound having a group), for example, compounds represented by the following formulae (5-1) to (5-16) and the following formula (5-24) can be used.

[0275] In the above reaction, instead of the epoxy compound, a compound having R in the formula (1) may be used. 1 The group (= becomes R 3 A compound having a leaving group) and a leaving group (hereinafter, sometimes referred to as a "leaving group-containing compound"). As the leaving group-containing compound, compounds represented by the following formulas (5-25) to (5-27) can be used. MOM in formulas (5-25) and (5-26) represents a methoxymethyl group. Ts in formulas (5-25) to (5-27) represents a tosyl group.

[0276]

[0277] When a fluorine-based compound is reacted with an epoxy compound (or a compound having a leaving group), the hydroxyl group of the epoxy compound (or a compound having a leaving group) may be protected with an appropriate protecting group and then reacted with the fluorine-based compound.

[0278] The epoxy compound (for example, the epoxy compound represented by formula (5-1)) can be produced by, for example, reacting an alcohol compound which may be appropriately protected with a halogen compound having an epoxy group as represented by the following formula (6-1).

[0279]

[0280] The epoxy compound (for example, the epoxy compound represented by formula (5-5)) can be produced, for example, by reacting an alcohol compound having a vinyl group with a halogen compound having an alcohol that can be appropriately protected, and then oxidizing the resulting compound by reacting it with m-chloroperbenzoic acid (mCPBA), as shown in the following formula (6-2).

[0281]

[0282] The epoxy compound (for example, the epoxy compound represented by formula (5-10)) can be produced by, for example, reacting a halogen compound having an alcohol which may be appropriately protected and a halogen compound having an epoxy group with a diol compound in sequence as represented by the following formula (6-3).

[0283]

[0284] The epoxy compound (or the compound having a leaving group) can be purchased as a commercial item and used.

[0285] By performing the above steps, R in formula (1) is obtained. 1 With R 3 Same compound.

[0286] In formula (1), in order to make R 1 With R 3 The same compound can be used in the following manner.

[0287] First, prepare the R 2 The two ends of the corresponding perfluoropolyether chain are respectively configured with a fluorine-based compound of a hydroxymethyl group (-CH2OH). The hydroxyl groups of the hydroxymethyl groups configured at the two ends of the fluorine-based compound are reacted with a halogen compound having a vinyl group at the end. Thus, a compound having a vinyl group at both ends of the chain structure comprising a perfluoropolyether chain is obtained.

[0288] Next, the vinyl groups at both ends of the obtained compound are oxidized to obtain a compound having epoxy groups at both ends of the chain structure containing a perfluoropolyether chain. The epoxy groups at both ends are subjected to a ring-opening reaction to convert the compound into 1,2-diol. By performing the above steps, R in formula (1) is obtained. 1 With R 3 Same compound.

[0289] (R 1 With R 3 Different situations)

[0290] In formula (1), in order to make R 1 With R 3 Different compounds are first prepared in the same manner as R in formula (1) 2 The corresponding perfluoropolyether chain has fluorine compounds having hydroxymethyl groups (-CH2OH) at both ends.

[0291] 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 The epoxy group of the epoxy compound of the group is reacted. Thus, the epoxy group of the epoxy compound with R is obtained. 2 One end of the corresponding perfluoropolyether chain has 1 The corresponding radical is the intermediate compound 1 (first reaction).

[0292] Next, the intermediate compound 1 is reacted with a compound having a R 3 The epoxy compound of the group is reacted (second reaction).

[0293] In the first reaction and / or the second reaction, a compound having a leaving group may be used instead of the epoxy compound.

[0294] In R 1 With R 3When one is a terminal group represented by formula (2) and the other is a terminal group that does not conform to formula (2), as the epoxy compound corresponding to the terminal group that does not conform to formula (2), for example, the epoxy compounds represented by the following formulas (5-17) to (5-23) can be used. In formulas (5-17), (5-18), (5-21) to (5-23), THP represents a tetrahydropyranyl group.

[0295]

[0296] By performing the above steps, R in formula (1) is obtained. 1 With R 3 Different compounds.

[0297] [Lubricant for magnetic recording media]

[0298] The lubricant for magnetic recording media according to the present embodiment contains the fluorine-containing ether compound represented by the above formula (1).

[0299] The lubricant of the present embodiment may be mixed with a known material used as a lubricant material as necessary, within a range that does not impair the properties brought about by the inclusion of the fluorine-containing ether compound represented by the above formula (1).

[0300] 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 known material used in combination with the lubricant of the present embodiment preferably has a number average molecular weight of 1,000 to 10,000.

[0301] 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 70% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more.

[0302] 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 having excellent corrosion resistance and capable of suppressing detachment.

[0303] [Magnetic recording media]

[0304] The magnetic recording medium of this embodiment includes at least a magnetic layer, a protective layer, and a lubricating layer provided in this order on a substrate.

[0305] 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.

[0306] Figure 1 This is a schematic cross-sectional view showing one embodiment of the magnetic recording medium of the present invention.

[0307] 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 .

[0308] "Substrate"

[0309] 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.

[0310] In addition, as the substrate 11, a non-magnetic substrate formed of a non-metallic material such as glass, ceramics, silicon, silicon carbide, carbon, or resin can be used, or a non-magnetic substrate having a film of NiP or NiP alloy formed on a base formed of these non-metallic materials can be used.

[0311] "Attachment Layer"

[0312] 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.

[0313] 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.

[0314] "Soft magnetic layer"

[0315] The soft magnetic layer 13 preferably has a structure in which a first soft magnetic film, an intermediate layer including 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 antiferrocoupled (AFC) by sandwiching the intermediate layer including a Ru film between the two soft magnetic films.

[0316] Examples of the material of the first soft magnetic film and the second soft magnetic film include CoZrTa alloy and CoFe alloy.

[0317] 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. This promotes the amorphization of the first soft magnetic film and the second soft magnetic film. As a result, the orientation of the first base layer (seed layer) can be improved, and the floating amount of the magnetic head can be reduced.

[0318] The soft magnetic layer 13 can be formed by, for example, sputtering.

[0319] "1st base layer"

[0320] 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.

[0321] 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, a CrTi alloy layer, and the like.

[0322] The first base layer 14 can be formed by, for example, sputtering.

[0323] "Second base layer"

[0324] The second underlayer 15 is a layer that is controlled so as to improve the orientation of the magnetic layer 16. The second underlayer 15 is preferably a layer formed of Ru or a Ru alloy.

[0325] 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 layers may be composed of the same material, or at least one layer may be composed of a different material.

[0326] The second base layer 15 can be formed by, for example, sputtering.

[0327] "Magnetic layer"

[0328] The magnetic layer 16 is made of a magnetic film whose easy magnetization axis is oriented in a vertical or horizontal direction relative to the substrate surface. The magnetic layer 16 is a layer containing Co and Pt. In order to improve the SNR characteristics, the magnetic layer 16 may be a layer containing oxide, Cr, B, Cu, Ta, Zr, etc.

[0329] 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 .

[0330] The magnetic layer 16 may be composed of a single layer or a plurality of magnetic layers formed of materials having different compositions.

[0331] 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 order from the bottom, the first magnetic layer is preferably a granular structure formed by a material containing Co, Cr, Pt, and further 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 suitable. In addition, the first magnetic layer is preferably formed by a composite oxide to which two or more oxides are added. Among them, Cr2O3-SiO2, Cr2O3-TiO2, SiO2-TiO2, etc. can be particularly suitable. In addition to Co, Cr, Pt, and oxides, the first magnetic layer can also contain one or more elements selected from B, Ta, Mo, Cu, Nd, W, Nb, Sm, Tb, Ru, and Re.

[0332] 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.

[0333] The third magnetic layer is preferably a non-granular structure formed of a material containing Co, Cr, and Pt and containing no oxide. In addition to Co, Cr, and Pt, the third magnetic layer may contain one or more elements selected from B, Ta, Mo, Cu, Nd, W, Nb, Sm, Tb, Ru, Re, and Mn.

[0334] 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.

[0335] The non-magnetic layer arranged between adjacent magnetic layers of the magnetic layer 16 can be suitably made of, for example, Ru, Ru alloy, CoCr alloy, CoCrX1 alloy (X1 represents one or more elements selected from Pt, Ta, Zr, Re, Ru, Cu, Nb, Ni, Mn, Ge, Si, O, N, W, Mo, Ti, V, and B), etc.

[0336] It is preferable to use an alloy material containing oxide, metal nitride, or metal carbide in the non-magnetic layer provided between adjacent magnetic layers of the magnetic layer 16. 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.

[0337] The non-magnetic layer can be formed by, for example, sputtering.

[0338] 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 perpendicularly to the substrate surface. The magnetic layer 16 may be an in-plane magnetic recording magnetic layer.

[0339] 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.

[0340] "Protective layer"

[0341] 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 group (especially hydroxyl group) contained in the fluorine-containing ether compound in the lubricating layer 18 is further improved, so it is preferred.

[0342] 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).

[0343] 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.

[0344] 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.

[0345] As a method for forming 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 or toluene, an IBD (ion beam deposition) method, or the like can be used.

[0346] When a carbon-based protective layer is formed as the protective layer 17, for example, a film can be formed by 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.

[0347] "Lubricating layer"

[0348] 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.

[0349] like Figure 1 As 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.

[0350] When the protective layer 17 disposed under the lubricating layer 18 is a carbon-based protective layer, the lubricating layer 18 is particularly bonded with the protective layer 17 with a 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 coverage rate even if the thickness of the lubricating layer 18 is thin, and contamination of the surface of the magnetic recording medium 10 can be effectively prevented.

[0351] 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 is not island-shaped or mesh-shaped but is formed with 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 less than 2.0nm, the lubricating layer 18 can be fully filmized, and the floating amount of the magnetic head can be fully reduced.

[0352] "Method for forming a lubricating layer"

[0353] Examples of a method for forming the lubricating layer 18 include a method of preparing a magnetic recording medium in which each layer up to the protective layer 17 is formed on the substrate 11 , applying a lubricating layer forming solution on the protective layer 17 , and drying the solution.

[0354] The lubricant layer-forming solution is obtained by dispersing and dissolving the lubricant for a magnetic recording medium of the above-described embodiment in a solvent as necessary to obtain a viscosity and a concentration suitable for a coating method.

[0355] 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 DuPont Mitsui Fluoro Chemical Co., Ltd.) and Asahicrine (registered trademark) AE-3000 (trade name, manufactured by AGC Corporation).

[0356] The coating method of the lubricating layer forming solution is not particularly limited, and examples thereof include a spin coating method, a spray method, a paper coating method, and a dipping method.

[0357] When the dipping method is used, for example, the following method can be used. First, the substrate 11 on which each layer up to the protective layer 17 is formed is dipped in the lubricating layer forming solution placed in the dipping tank of the dipping coating device. Next, 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.

[0358] By using 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.

[0359] In the present embodiment, it is preferable to perform heat treatment on the substrate 11 on which the lubricating layer 18 is formed. 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.

[0360] The heat treatment temperature is preferably 100° C. to 180° C., more preferably 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 is sufficiently obtained. In addition, by setting the heat treatment temperature to 180° C. or lower, thermal decomposition of the lubricating layer 18 caused by the heat treatment can be prevented. The heat treatment time can be appropriately adjusted according to the heat treatment temperature, and is preferably 10 minutes to 120 minutes.

[0361] In the present 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.

[0362] The magnetic recording medium 10 of the present embodiment has at least a magnetic layer 16, a protective layer 17, and a lubricating layer 18 arranged in sequence on a substrate 11. For 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 good corrosion resistance and can suppress shedding. Therefore, the magnetic recording medium 10 of the present embodiment has excellent reliability, especially corrosion resistance and shedding suppression, and durability. Therefore, the magnetic recording medium 10 of the present embodiment can help reduce the magnetic spacing, can make the head floating amount low (for example, less than 10nm), and can operate stably for a long time even in a harsh environment with a variety of uses. Therefore, the magnetic recording medium 10 of the present embodiment is particularly suitable as a magnetic disk mounted on a magnetic disk device of the LUL (Load Unload) method.

[0363] Example

[0364] Hereinafter, the present invention will be described in more detail by way of Examples and Comparative Examples. In addition, the present invention is not limited to the following Examples.

[0365] [Example 1]

[0366] The compound represented by the above formula (AA) was obtained by the method shown below.

[0367] In a 100 mL eggplant flask under nitrogen atmosphere, add HOCH2CF2O (CF2CF2O) h (CF2O) i 5 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), 2.70 g of a compound represented by the above formula (5-1), and 5 mL of tert-butyl alcohol were stirred at room temperature until the mixture became uniform to prepare a mixture. 0.30 g of potassium tert-butylate was added to the mixture, and the mixture was stirred at 70°C for 16 hours to react.

[0368] The compound represented by formula (5-1) is synthesized by protecting the 1,2-diol site of 1,2,4-butanetriol with acetone and then reacting the hydroxyl group at the 4-position with epibromohydrin.

[0369] The reaction solution obtained after the reaction was returned to room temperature, 10 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 4 hours. Then, the reaction solution was transferred little by little to a separatory funnel added with 25 mL of saturated sodium bicarbonate water, and extracted twice with 50 mL of ethyl acetate. The organic layer was washed with 25 mL of brine, 25 mL of saturated sodium bicarbonate water, and 25 mL of brine in this order, and dehydrated with anhydrous sodium sulfate. After the desiccant was separated by filtration, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 3.71 g of compound (AA) (Rf1 in formula (AA) is the PFPE chain shown in the above formula (4-1). In Rf1, h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0370] The obtained compound (AA) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0371] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0372] 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)

[0373] [Example 2]

[0374] The compound represented by the above formula (AB) was obtained by the method shown below.

[0375] The same operation as in Example 1 was performed except that the compound represented by formula (5-2) was used instead of the compound represented by formula (5-1), thereby obtaining 3.85 g of compound (AB) (Rf1 in formula (AB) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0376] The compound represented by formula (5-2) is synthesized by protecting the 1,2-diol site of 1,2,6-hexanetriol with acetone and then reacting the hydroxyl group at the 6-position with epibromohydrin.

[0377] The obtained compound (AB) is subjected to 1 H-NMR and 19The structure was identified based on the following results from F-NMR measurement.

[0378] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (12H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0379] 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)

[0380] [Example 3]

[0381] The compound represented by the above formula (AC) was obtained by the method shown below.

[0382] Instead of the compound represented by formula (5-1), the compound represented by formula (5-3) was used. The same operations as in Example 1 were carried out to obtain 3.85 g of compound (AC) (Rf1 in formula (AC) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0383] The compound represented by formula (5-3) is synthesized by protecting the 1,2-diol site of 1,2,8-octantriol with acetone and then reacting the hydroxyl group at the 8-position with epibromohydrin.

[0384] The obtained compound (AC) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0385] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (20H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0386] 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)

[0387] [Example 4]

[0388] The compound represented by the above formula (AD) was obtained by the method shown below.

[0389] Instead of the compound represented by formula (5-1), the compound represented by formula (5-4) was used. Except for this, the same operation as in Example 1 was carried out to obtain 3.91 g of compound (AD) (Rf1 in formula (AD) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0390] The compound represented by formula (5-4) was synthesized by the method shown below. After protecting the 1,2-diol site of 1,2,4-butanetriol with acetone, the hydroxyl group at the 4-position was brominated and reacted with 3-butene-1-ol to obtain the compound. The vinyl group of the obtained compound was oxidized with m-chloroperbenzoic acid (mCPBA) to obtain the compound.

[0391] The obtained compound (AD) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0392] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (8H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0393] 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)

[0394] [Example 5]

[0395] The compound represented by the above formula (AE) was obtained by the method shown below.

[0396] Instead of the compound represented by formula (5-1), the compound represented by formula (5-5) was used. The same operations as in Example 1 were carried out to obtain 3.26 g of compound (AE) (Rf1 in formula (AE) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0397] The compound represented by formula (5-5) is synthesized by reacting a compound obtained by brominating the hydroxyl group of solketal (2,2-dimethyl-1,3-dioxolane-4-methanol) with 3-butene-1-ol, and oxidizing the vinyl group of the obtained compound using m-chloroperbenzoic acid (mCPBA).

[0398] The obtained compound (AE) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0399] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0400] 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)

[0401] [Example 6]

[0402] The compound represented by the above formula (AF) was obtained by the method shown below.

[0403] Instead of the compound represented by formula (5-1), the compound represented by formula (5-6) was used. The same operations as in Example 1 were carried out to obtain 3.43 g of compound (AF) (Rf1 in formula (AF) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0404] The compound represented by formula (5-6) is synthesized by reacting a compound obtained by brominating the hydroxyl group of glycerol acetonate with 5-hexen-1-ol, and oxidizing the vinyl group of the obtained compound using m-chloroperbenzoic acid (mCPBA).

[0405] The obtained compound (AF) was subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0406] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (12H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0407] 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)

[0408] [Example 7]

[0409] The compound represented by the above formula (AG) was obtained by the method shown below.

[0410] Instead of the compound represented by formula (5-1), the compound represented by formula (5-7) was used. Except for this, the same operations as in Example 1 were carried out to obtain 3.56 g of compound (AG) (Rf1 in formula (AG) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0411] The compound represented by formula (5-7) is synthesized by reacting a compound obtained by brominating the hydroxyl group of glycerol acetonate with 7-octen-1-ol, and oxidizing the vinyl group of the obtained compound using m-chloroperbenzoic acid (mCPBA).

[0412] The obtained compound (AG) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0413] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (20H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0414] 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)

[0415] [Example 8]

[0416] The compound represented by the above formula (AH) was obtained by the method shown below.

[0417] Instead of the compound represented by formula (5-1), the compound represented by formula (5-8) was used. Except for this, the same operations as in Example 1 were carried out to obtain 3.40 g of compound (AH) (Rf1 in formula (AH) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0418] The compound represented by formula (5-8) was synthesized by the method shown below. The epoxy group of 1,2-epoxy-5-hexene was ring-opened with dilute sulfuric acid. The 1,2-diol site generated by the ring-opening was protected with acetone, and the vinyl group of the obtained compound was oxidized with meta-chloroperbenzoic acid (mCPBA).

[0419] The obtained compound (AH) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0420] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (8H), 3.40-3.85 (18H), 3.85-4.10 (4H)

[0421] 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)

[0422] [Example 9]

[0423] The compound represented by the above formula (AI) was obtained by the method shown below.

[0424] Instead of the compound represented by formula (5-1), the compound represented by formula (5-9) was used. Except for this, the same operations as in Example 1 were carried out to obtain 3.45 g of compound (AI) (Rf1 in formula (AI) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0425] The compound represented by formula (5-9) was synthesized by the method shown below. One vinyl group of 1,7-octadiene was oxidized using m-chloroperbenzoic acid (mCPBA). The epoxy group produced by the oxidation was ring-opened using dilute sulfuric acid. The 1,2-diol site produced by the ring-opening was protected using acetone, and the vinyl group of the obtained compound was oxidized using mCPBA to synthesize.

[0426] The obtained compound (AI) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0427] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (16H), 3.40-3.85 (18H), 3.85-4.10 (4H)

[0428] 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)

[0429] [Example 10]

[0430] The compound represented by the above formula (AJ) was obtained by the method shown below.

[0431] Instead of the compound represented by formula (5-1), the compound represented by formula (5-10) was used. Except for this, the same operations as in Example 1 were carried out to obtain 3.68 g of compound (AJ) (Rf1 in formula (AJ) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0432] The compound represented by formula (5-10) is synthesized by reacting one hydroxyl group of 1,3-propylene glycol with a compound obtained by brominating the hydroxyl group of glycerol acetone, and then reacting the other hydroxyl group with epibromohydrin.

[0433] The obtained compound (AJ) was subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0434] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (34H), 3.85-4.10 (4H)

[0435] 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)

[0436] [Example 11]

[0437] The compound represented by the above formula (AK) was obtained by the method shown below.

[0438] Instead of the compound represented by formula (5-1), the compound represented by formula (5-11) was used. Except for this, the same operation as in Example 1 was carried out to obtain 3.76 g of compound (AK) (Rf1 in formula (AK) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0439] The compound represented by formula (5-11) is synthesized by reacting one hydroxyl group of 2,2-dimethyl-1,3-propanediol with a compound obtained by brominating the hydroxyl group of glycerol acetone acetal, and then reacting the other hydroxyl group with epibromohydrin.

[0440] The obtained compound (AK) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0441] 1 H-NMR (acetone-D6): δ [ppm] = 1.20-1.25 (12H), 3.40-3.85 (34H), 3.85-4.10 (4H)

[0442] 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)

[0443] [Example 12]

[0444] The compound represented by the above formula (AL) was obtained by the method shown below.

[0445] Instead of the compound represented by formula (5-1), the compound represented by formula (5-12) was used. Except for this, the same operations as in Example 1 were carried out to obtain 3.78 g of compound (AL) (Rf1 in formula (AL) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0446] The compound represented by formula (5-12) is synthesized by reacting one hydroxyl group of 1,4-butanediol with a compound obtained by brominating the hydroxyl group of glycerol acetone acetal, and then reacting the other hydroxyl group with epibromohydrin.

[0447] The obtained compound (AL) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0448] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (8H), 3.40-3.85 (34H), 3.85-4.10 (4H)

[0449] 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)

[0450] [Example 13]

[0451] The compound represented by the above formula (AM) was obtained by the method shown below.

[0452] Instead of the compound represented by formula (5-1), the compound represented by formula (5-13) was used. Except for this, the same operations as in Example 1 were carried out to obtain 3.85 g of compound (AM) (Rf1 in formula (AM) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0453] The compound represented by formula (5-13) is synthesized by reacting one hydroxyl group of 2,3-dimethyl-1,4-butanediol with a compound obtained by brominating the hydroxyl group of glycerol acetone acetal, and then reacting the other hydroxyl group with epibromohydrin.

[0454] The obtained compound (AM) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0455] 1 H-NMR (acetone-D6): δ [ppm] = 1.20-1.25 (12H), 1.65-1.85 (4H), 3.40-3.85 (34H), 3.85-4.10 (4H)

[0456] 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)

[0457] [Example 14]

[0458] The compound represented by the above formula (AN) was obtained by the method shown below.

[0459] Instead of the compound represented by formula (5-1), the compound represented by formula (5-14) was used. Except for this, the same operations as in Example 1 were carried out to obtain 3.81 g of compound (AN) (Rf1 in formula (AN) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0460] The compound represented by formula (5-14) is synthesized by reacting one hydroxyl group of 1,8-octanediol with a compound obtained by brominating the hydroxyl group of glycerol acetone, and then reacting the other hydroxyl group with epibromohydrin.

[0461] The obtained compound (AN) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0462] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (24H), 3.40-3.85 (34H), 3.85-4.10 (4H)

[0463] 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)

[0464] [Example 15]

[0465] The compound represented by the above formula (AO) was obtained by the method shown below.

[0466] Instead of the compound represented by formula (5-1), the compound represented by formula (5-15) was used. Except for this, the same operations as in Example 1 were carried out to obtain 4.02 g of compound (AO) (Rf1 in formula (AO) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0467] The compound represented by formula (5-15) is synthesized by reacting one hydroxyl group of 2,2,3,3-tetrafluoro-1,4-butanediol with a compound obtained by brominating the hydroxyl group of glycerol acetone acetal, and then reacting the other hydroxyl group with epibromohydrin.

[0468] The obtained compound (AO) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0469] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-3.85 (26H), 3.85-4.10 (12H)

[0470] 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), -128.5 to 130.0 (8F)

[0471] [Example 16]

[0472] The compound represented by the above formula (AP) was obtained by the method shown below.

[0473] Instead of the compound represented by formula (5-1), the compound represented by formula (5-16) was used. Except for this, the same operations as in Example 1 were carried out to obtain 4.31 g of compound (AP) (Rf1 in formula (AP) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0474] The compound represented by formula (5-16) is synthesized by reacting one hydroxyl group of 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-1,8-octanediol with a compound obtained by brominating the hydroxyl group of glycerol acetone acetal, and then reacting the other hydroxyl group with epibromohydrin.

[0475] The obtained compound (AP) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0476] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-3.85 (26H), 3.85-4.10 (12H)

[0477] 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), -122.5 to -124.5 (16F), -128.5 to 130.0 (8F)

[0478] [Example 17]

[0479] The compound represented by the above formula (AQ) was obtained by the method shown below.

[0480] In a 100 mL eggplant flask under nitrogen atmosphere, add HOCH2CF2O (CF2CF2O) h (CF2O) i 5 g of 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), 4.50 g of 1-bromo-4-pentene, and 10 mL of N,N-dimethylformamide were stirred at room temperature until uniform to prepare a mixture. 1.20 g of sodium hydride (purity 60%, containing mineral oil) was added to the mixture, and the mixture was stirred at 70°C for 16 hours to react.

[0481] The reaction product obtained after the reaction was cooled to 25°C, transferred to a separatory funnel to which 50 mL of water was added, 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 and separating the desiccant, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 4.76 g of the compound represented by the following formula (7-1) as an intermediate compound.

[0482]

[0483] (Rf1 in formula (7-1) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.)

[0484] Next, in a 100 mL eggplant-shaped flask under a nitrogen atmosphere, 4.76 g of the compound represented by the formula (7-1) obtained as the intermediate compound, 20 mL of dichloromethane, and 3.15 g of m-chloroperbenzoic acid (mCPBA (purity 73%, containing water)) were added and the mixture was stirred at room temperature for 16 hours to react.

[0485] The reaction solution obtained after the reaction was added with 50 mL of an aqueous solution of 3.18 g of sodium sulfite to inactivate the excess mCPBA. After the generated solid was separated by filtration, it was transferred to a separatory funnel and extracted three times with 100 mL of dichloromethane. The organic layer was washed with water and dehydrated with anhydrous sodium sulfate. After the desiccant was separated by filtration, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 4.21 g of the compound represented by the following formula (7-2) as an intermediate compound.

[0486]

[0487] (Rf1 in formula (7-2) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.)

[0488] Next, 4.21 g of the compound represented by formula (7-2) obtained as the intermediate compound, 20 mL of acetone, and 20 mL of 10% dilute sulfuric acid were added to a 100 mL eggplant flask under a nitrogen atmosphere, and the mixture was stirred and reacted at room temperature for 16 hours.

[0489] After the reaction, 20 mL of saturated sodium bicarbonate water was added to the reaction solution obtained for neutralization, and the generated solid was separated by filtration. Then, it was transferred to a separatory funnel and extracted three times with 100 mL of ethyl acetate. The organic layer was washed with water and dehydrated with anhydrous sodium sulfate. After the desiccant was separated by filtration, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain compound (AQ) (Rf1 in formula (AQ) is the PFPE chain shown in the above formula (4-1). In Rf1, h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.) 3.32 g.

[0490] The obtained compound (AQ) was subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0491] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (8H), 3.40-3.85 (14H), 3.85-4.10 (4H)

[0492] 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)

[0493] [Example 18]

[0494] The compound represented by the above formula (AR) was obtained by the method shown below.

[0495] The same operation as in Example 17 was carried out except that 1-bromo-7-octene was used instead of 1-bromo-4-pentene, thereby obtaining 3.35 g of compound (AR) (Rf1 in formula (AR) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0496] The obtained compound (AR) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0497] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (20H), 3.40-3.85 (14H), 3.85-4.10 (4H)

[0498] 19F-NMR (acetone-D6): δ [ppm] = -55.5 to -51.5 (9F), -78.5 (2F), -80.5 (2F), -91.0 to -88.5 (18F)

[0499] [Example 19]

[0500] The compound represented by the above formula (AS) was obtained by the method shown below.

[0501] (First reaction)

[0502] In a 100 mL eggplant flask under nitrogen atmosphere, add HOCH2CF2O (CF2CF2O) h (CF2O) i 12.5 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), 2.70 g of a compound represented by the above formula (5-1), and 12 mL of tert-butyl alcohol were stirred at room temperature until the mixture became uniform to prepare a mixture. 1.10 g of potassium tert-butylate was added to the mixture, and the mixture was stirred at 70°C for 16 hours to react.

[0503] The reaction product obtained after the reaction was cooled to 25°C, transferred to a separatory funnel to which 100 mL of water was added, 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 and separating the desiccant, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 7.21 g of the compound represented by the following formula (8) as an intermediate compound 1.

[0504]

[0505] (Rf1 in formula (8) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.)

[0506] (Second reaction)

[0507] Next, in a nitrogen atmosphere, 7.21 g of the compound represented by formula (8) obtained as the intermediate compound 1, 2.70 g of the compound represented by formula (5-5), and 20 mL of tert-butanol were added to a 100 mL eggplant flask, and stirred at room temperature until the mixture became uniform to prepare a mixture. 0.55 g of potassium tert-butoxide was added to the mixture, and the mixture was stirred at 70° C. for 16 hours to react.

[0508] The reaction solution obtained after the reaction was returned to room temperature, 50 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 4 hours. Then, the reaction solution was transferred little by little to a separatory funnel added with 100 mL of saturated sodium bicarbonate water, and extracted twice with 200 mL of ethyl acetate. The organic layer was washed with 100 mL of brine, 100 mL of saturated sodium bicarbonate water, and 100 mL of brine in this order, and dehydrated with anhydrous sodium sulfate. After the desiccant was separated by filtration, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 3.44 g of compound (AS) (Rf1 in formula (AS) is the PFPE chain shown in the above formula (4-1). In Rf1, h representing the average degree of polymerization represents 4.5, and i representing the average degree of polymerization represents 4.5.).

[0509] The obtained compound (AS) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0510] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0511] 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)

[0512] [Example 20]

[0513] The compound represented by the above formula (BA) was obtained by the method shown below.

[0514] Instead of the compound represented by formula (5-5), the compound represented by formula (5-17) was used. Except for this, the same operation as in Example 19 was performed to obtain 3.61 g of compound (BA) (Rf1 in formula (BA) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0515] The compound represented by formula (5-17) is synthesized by protecting the hydroxyl group of ethylene glycol monoallyl ether with dihydropyran and then oxidizing the vinyl group with m-chloroperbenzoic acid (mCPBA).

[0516] The obtained compound (BA) is 1 H-NMR and19 The structure was identified based on the following results from F-NMR measurement.

[0517] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (2H), 3.40-3.85 (24H), 3.85-4.10 (4H)

[0518] 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)

[0519] [Example 21]

[0520] The compound represented by the above formula (BB) was obtained by the method shown below.

[0521] Instead of the compound represented by formula (5-5), the compound represented by formula (5-18) was used. Except for this, the same operation as in Example 19 was performed to obtain 3.61 g of compound (BB) (Rf1 in formula (BB) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0522] The compound represented by formula (5-18) was synthesized by the method shown below. Epichlorohydrin was reacted with 3-butene-1-ol in a 2-fold molar amount thereof. The hydroxyl group generated by the reaction was protected with dihydropyran. One vinyl group of the compound obtained by the reaction was oxidized with m-chloroperbenzoic acid (mCPBA) to synthesize the compound.

[0523] The obtained compound (BB) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0524] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (27H), 3.85-4.10 (4H), 5.20-5.80 (3H)

[0525] 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)

[0526] [Example 22]

[0527] The compound represented by the above formula (BC) was obtained by the method shown below.

[0528] Instead of the compound represented by formula (5-5), the compound represented by formula (5-19) was used. Except for this, the same operations as in Example 19 were performed to obtain 3.53 g of compound (BC) (Rf1 in formula (BC) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0529] The compound represented by formula (5-19) is synthesized by reacting the hydroxyl group of 2-acetylaminoethanol with epibromohydrin.

[0530] The obtained compound (BC) 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0531] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (2H), 1.90 (3H), 3.40-3.85 (23H), 3.85-4.10 (4H), 6.70-6.80 (1H)

[0532] 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)

[0533] [Example 23]

[0534] The compound represented by the above formula (BD) was obtained by the method shown below.

[0535] Instead of the compound represented by formula (5-5), the compound represented by formula (5-20) was used. Except for this, the same operations as in Example 19 were performed to obtain 3.72 g of compound (BD) (Rf1 in formula (BD) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0536] The compound represented by formula (5-20) is synthesized by reacting the hydroxyl group of 3-cyanopropanol with epibromohydrin.

[0537] The obtained compound (BD) was 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0538] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 1.90-2.00 (2H), 3.40-3.85 (21H), 3.85-4.10 (4H)

[0539] 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)

[0540] [Example 24]

[0541] The compound represented by the above formula (BE) was obtained by the method shown below.

[0542] Instead of the compound represented by formula (5-5), the compound represented by formula (5-21) was used. Except for this, the same operations as in Example 19 were performed to obtain 3.72 g of compound (BE) (Rf1 in formula (BE) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0543] The compound represented by formula (5-21) is synthesized by protecting the hydroxyl group of 3-butene-1-ol with dihydropyran and then oxidizing the vinyl group with m-chloroperbenzoic acid (mCPBA).

[0544] The obtained compound (BE) was 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0545] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (20H), 3.85-4.10 (4H)

[0546] 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)

[0547] [Example 25]

[0548] The compound represented by the above formula (BF) was obtained by the method shown below.

[0549] Instead of the compound represented by formula (5-5), the compound represented by formula (5-22) was used. Except for this, the same operations as in Example 19 were performed to obtain 3.72 g of compound (BF) (Rf1 in formula (BF) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0550] The compound represented by formula (5-22) is synthesized by protecting the two hydroxyl groups of 3-allyloxy-1,2-propanediol with dihydropyran and then oxidizing the vinyl group with m-chloroperbenzoic acid (mCPBA).

[0551] The obtained compound (BF) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0552] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (2H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0553] 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)

[0554] [Example 26]

[0555] The compound represented by the above formula (BG) was obtained by the method shown below.

[0556] Replace HOCH2CF2O(CF2CF2O) h (CF2O) i The compound shown in CF2CH2OH is 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 (Rf2 in formula (BG) is the PFPE chain represented by the above formula (4-2). In Rf2, j representing the average degree of polymerization is 4.5). 3.48 g of the compound was obtained.

[0557] The obtained compound (BG) was 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0558] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0559] 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)

[0560] [Example 27]

[0561] The compound represented by the above formula (BH) was obtained by the method shown below.

[0562] Replace HOCH2CF2O(CF2CF2O) h (CF2O) i The compound shown in CF2CH2OH is 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 1 to obtain 3.44 g of compound (BH) (Rf3 in formula (BH) is the PFPE chain represented by the above formula (4-3). In Rf3, k representing the average degree of polymerization is 3.0).

[0563] The obtained compound (BH) 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0564] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0565] 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)

[0566] [Example 28]

[0567] The compound represented by the above formula (CA) was obtained by the method shown below.

[0568] Replace HOCH2CF2O(CF2CF2O) h (CF2O) i CF2CH2OH (wherein h, which indicates the average degree of polymerization, is 4.5, and i, which indicates the average degree of polymerization, is 4.5.) was used, while HOCH2CF2O (CF2CF2O) was used. h (CF2O) i The same operation as in Example 1 was performed to obtain 3.15 g of the compound represented by CF2CH2OH (wherein h representing the average degree of polymerization is 7.0, and i representing the average degree of polymerization is 0).

[0569] The obtained compound (CA) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0570] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0571] 19 F-NMR (acetone-D6): δ [ppm] = -78.5 (4F), -91.0 to -88.5 (28F)

[0572] [Example 29]

[0573] The compound represented by the above formula (CB) was obtained by the method shown below.

[0574] Instead of the compound represented by formula (5-1), the compound represented by formula (5-5) was used. Except for this, the same operation as in Example 28 was performed to obtain 3.08 g of compound (CB) (Rf1 in formula (CB) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 7.0, and i representing the average degree of polymerization is 0.).

[0575] The obtained compound (CB) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0576] 1H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0577] 19 F-NMR (acetone-D6): δ [ppm] = -78.5 (4F), -91.0 to -88.5 (28F)

[0578] [Example 30]

[0579] The compound represented by the above formula (CC) was obtained by the method shown below.

[0580] Instead of the compound represented by formula (5-1), the compound represented by formula (5-5) was used. Except for this, the same operation as in Example 26 was carried out to obtain 3.24 g of compound (CC) (Rf2 in formula (CC) is the PFPE chain represented by the above formula (4-2). In Rf2, j representing the average degree of polymerization is 4.5.).

[0581] The obtained compound (CC) 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0582] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0583] 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)

[0584] [Example 31]

[0585] The compound represented by the above formula (CD) was obtained by the method shown below.

[0586] Instead of the compound represented by formula (5-1), the compound represented by formula (5-5) was used. Except for this, the same operation as in Example 27 was carried out to obtain 2.95 g of compound (CD) (Rf3 in formula (CD) is the PFPE chain represented by the above formula (4-3). In Rf3, k representing the average degree of polymerization is 3.0.).

[0587] The obtained compound (CD) was subjected to 1 H-NMR and 19The structure was identified based on the following results from F-NMR measurement.

[0588] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0589] 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)

[0590] [Example 32]

[0591] The compound represented by the above formula (CE) was obtained by the method shown below.

[0592] Instead of the compound represented by formula (5-1), the compound represented by formula (5-24) was used. Except for this, the same operations as in Example 1 were carried out to obtain 3.35 g of compound (CE) (Rf1 in formula (CE) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0593] The compound represented by formula (5-24) is synthesized by reacting one hydroxyl group of 2-methyl-1,3-propanediol with a compound obtained by brominating the hydroxyl group of glycerol acetone acetal, and then reacting the other hydroxyl group with epibromohydrin.

[0594] The obtained compound (CE) was 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0595] 1 H-NMR (acetone-D6): δ [ppm] = 1.20-1.25 (6H), 1.25-1.35 (2H), 3.40-3.85 (34H), 3.85-4.10 (4H)

[0596] 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)

[0597] [Example 33]

[0598] The compound represented by the above formula (CF) was obtained by the method shown below.

[0599] Under nitrogen atmosphere, add HOCH2CF2CF2O (CF2CF2CF2O) into a 100 mL eggplant flask. j 5 g of a compound represented by CF2CF2CH2OH (wherein j representing the average degree of polymerization is 4.5) (number average molecular weight 1000, molecular weight distribution 1.1), 4.83 g of a compound represented by the above formula (5-25), and 20 mL of N,N-dimethylformamide were stirred at room temperature until uniform to prepare a mixture. 7.14 g of cesium carbonate was added to the mixture, and the mixture was stirred at 70°C for 16 hours to react.

[0600] The compound represented by formula (5-25) is synthesized by the following method. First, the hydroxyl group of 3-butene-1-ol is protected with dihydropyran, and then the olefinic group is oxidized with m-chloroperbenzoic acid. Then, acetone glycerol is reacted with the obtained compound, and the secondary hydroxyl group of the generated compound is protected with chloromethyl methyl ether. After the THP group is selectively deprotected by reacting the obtained compound represented by the following formula (5-25A) with an acid, the primary hydroxyl group is reacted with p-toluenesulfonyl chloride to obtain the compound represented by formula (5-25).

[0601] The selective deprotection of the THP group was carried out by adding pyridinium p-toluenesulfonate as an acid catalyst to a mixture of 3.60 g (10.3 mmol) of the compound represented by formula (5-25A) and a mixed solvent of 16 g of 2-propanol and 16 g of acetone. 0.52 g (2.07 mmol) was added and stirred in an air atmosphere at a reaction temperature of 55°C for 7 hours.

[0602]

[0603] The reaction solution obtained after the reaction of the above-mentioned fluorine-based compound with the compound represented by formula (5-25) was restored to room temperature, 10 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 4 hours. Then, the reaction solution was transferred little by little to a separatory funnel added with 25 mL of saturated sodium bicarbonate water, and extracted twice with 50 mL of ethyl acetate. The organic layer was washed with 25 mL of brine, 25 mL of saturated sodium bicarbonate water, and 25 mL of brine in this order, and dehydrated with anhydrous sodium sulfate. After filtering and separating the desiccant, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 2.81 g of compound (CF) (Rf1 in formula (CF) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.).

[0604] The obtained compound (CF) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0605] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0606] 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)

[0607] [Example 34]

[0608] The compound represented by the above formula (CG) was obtained by the method shown below.

[0609] Instead of using the compound represented by formula (5-25), the compound represented by formula (5-26) was used. Except for this, the same operation as in Example 33 was performed to obtain 2.92 g of compound (CG) (Rf2 in formula (CG) is the PFPE chain represented by the above formula (4-2). In Rf2, j representing the average degree of polymerization is 4.5.)

[0610] The compound represented by formula (5-26) is synthesized by the following method. First, the hydroxyl group of 5-hexene-1-ol is protected with dihydropyran, and then the alkenyl group is oxidized with m-chloroperbenzoic acid. Then, acetone glycerol is reacted with the obtained compound, and the secondary hydroxyl group of the generated compound is protected with chloromethyl methyl ether. After the THP group is selectively deprotected by reacting the obtained compound with an acid, the primary hydroxyl group is reacted with p-toluenesulfonyl chloride to obtain the compound represented by formula (5-26).

[0611] The obtained compound (CG) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0612] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (12H), 3.40-3.85 (26H), 3.85-4.10 (4H)

[0613] 19F-NMR (acetone-D6): δ [ppm] = -84.0 to -83.0 (18F), -86.4 (4F), -124.3 (4F), -130.0 to -129.0 (9F)

[0614] [Example 35]

[0615] The compound represented by the above formula (CH) was obtained by the method shown below.

[0616] Under nitrogen atmosphere, add HOCH2CF2CF2O (CF2CF2CF2O) into a 100 mL eggplant flask. j 12 g of a compound represented by CF2CF2CH2OH (wherein j represents the average degree of polymerization and is 4.5) (number average molecular weight 1000, molecular weight distribution 1.1), 1.81 g of a compound represented by the above formula (5-27), and 20 mL of N,N-dimethylformamide were stirred at room temperature until the mixture became uniform to prepare a mixture. 5.51 g of cesium carbonate was added to the mixture, and the mixture was stirred at 50°C for 16 hours to react.

[0617] The compound represented by formula (5-27) is synthesized by protecting the 1,2-diol site of 1,2,6-hexanetriol with acetone and then reacting the hydroxyl group at the 6-position with p-toluenesulfonyl chloride.

[0618] The reaction product obtained after the reaction was cooled to 25°C, transferred to a separatory funnel to which 100 mL of water was added, 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 and separating the desiccant, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 5.96 g of the compound represented by the following formula (9) as an intermediate compound 1.

[0619]

[0620] (Rf2 in formula (9) is the PFPE chain represented by the above formula (4-2). In Rf2, j indicating the average degree of polymerization is 4.5.)

[0621] Next, 5.96 g of the compound represented by formula (9) obtained as the intermediate compound 1, 2.76 g of the compound represented by formula (5-26), and 20 mL of N,N-dimethylformamide were added to a 100 mL eggplant flask under a nitrogen atmosphere, and stirred at room temperature until the mixture became uniform to prepare a mixture. 3.65 g of cesium carbonate was added to the mixture, and the mixture was stirred at 50° C. for 16 hours to react.

[0622] The reaction solution obtained after the reaction was returned to room temperature, 50 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 4 hours. Then, the reaction solution was transferred little by little to a separatory funnel added with 100 mL of saturated sodium bicarbonate water, and extracted twice with 200 mL of ethyl acetate. The organic layer was washed with 100 mL of brine, 100 mL of saturated sodium bicarbonate water, and 100 mL of brine in this order, and dehydrated with anhydrous sodium sulfate. After the desiccant was separated by filtration, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 2.41 g of compound (CH) (Rf2 in formula (CH) is the PFPE chain shown in the above formula (4-2). In Rf2, j representing the average degree of polymerization is 4.5.).

[0623] The obtained compound (CH) 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0624] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (12H), 3.40-3.85 (20H), 3.85-4.10 (4H)

[0625] 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)

[0626] [Example 36]

[0627] The compound represented by the above formula (CI) was obtained by the method shown below.

[0628] Instead of the compound represented by formula (5-1), the compound represented by formula (5-8) was used. Except for this, the same operation as in Example 26 was carried out to obtain 3.13 g of compound (CI) (Rf2 in formula (CI) is the PFPE chain represented by the above formula (4-2). In Rf2, j representing the average degree of polymerization is 4.5.).

[0629] The obtained compound (CI) 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0630] 1H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (8H), 3.40-3.85 (18H), 3.85-4.10 (4H)

[0631] 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)

[0632] [Example 37]

[0633] The compound represented by the above formula (CJ) was obtained by the method shown below.

[0634] Instead of the compound represented by formula (5-1), the compound represented by formula (5-10) was used. Except for this, the same operation as in Example 26 was performed to obtain 3.52 g of compound (CJ) (Rf2 in formula (CJ) is the PFPE chain represented by the above formula (4-2). In Rf2, j representing the average degree of polymerization is 4.5.

[0635] The obtained compound (CJ) 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0636] 1 H-NMR (acetone-D6): δ [ppm] = 1.65-1.85 (4H), 3.40-3.85 (34H), 3.85-4.10 (4H)

[0637] 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)

[0638] [Example 38]

[0639] The compound represented by the above formula (CK) was obtained by the method shown below.

[0640] Instead of the compound represented by formula (5-1), the compound represented by formula (5-15) was used. Except for this, the same operation as in Example 26 was performed to obtain 3.61 g of compound (CK) (Rf2 in formula (CK) is the PFPE chain represented by the above formula (4-2). In Rf2, j representing the average degree of polymerization is 4.5.

[0641] The obtained compound (CK) was 1H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0642] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-3.85 (26H), 3.85-4.10 (12H)

[0643] 19 F-NMR (acetone-D6): δ [ppm] = -84.0 to -83.0 (18F), -86.4 (4F), -124.3 (4F), -130.0 to -128.5 (17F)

[0644] The compounds (AA) to (AS), (BA) to (BH), and (CA) to (CK) of Examples 1 to 38 obtained in this manner were respectively substituted into the formula (1), and R 1 , R 2 , R 3 The structures of are shown in Tables 1 and 2.

[0645] [Table 1]

[0646]

[0647] [Table 2]

[0648]

[0649] [Comparative Example 1]

[0650] According to the method described in Patent Document 1, a compound represented by the following formula (ZA) was synthesized.

[0651]

[0652] (Rf2 in formula (ZA) is the PFPE chain represented by the above formula (4-2). In Rf2, j indicating the average degree of polymerization is 4.5.)

[0653] [Comparative Example 2]

[0654] According to the method described in Patent Document 2, a compound represented by the following formula (ZB) was synthesized.

[0655]

[0656] (Rf2 in formula (ZB) is the PFPE chain represented by the above formula (4-2). In Rf2, j indicating the average degree of polymerization is 4.5.)

[0657] [Comparative Example 3]

[0658] According to the method described in Patent Document 3, a compound represented by the following formula (ZC) was synthesized.

[0659]

[0660] (Rf1 in formula (ZC) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.)

[0661] [Comparative Example 4]

[0662] The compound represented by the following formula (ZD) was synthesized by the following method.

[0663]

[0664] (Rf2 in formula (ZD) is the PFPE chain represented by the above formula (4-2). In Rf2, j indicating the average degree of polymerization is 4.5.)

[0665] Instead of the compound represented by formula (5-1), a compound represented by formula (5-23) is used instead of HOCH2CF2O (CF2CF2O) h (CF2O) i The compound shown in CF2CH2OH is used instead of HOCH2CF2CF2O (CF2CF2CF2O). j The same operation as in Example 1 was carried out except that 2.81 g of compound (ZD) was obtained by adding CF2CF2CH2OH (wherein j representing the average polymerization degree is 4.5).

[0666] The obtained compound (ZD) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0667] 1 H-NMR (acetone-D6): δ [ppm] = 3.40-3.85 (14H), 3.85-4.10 (4H)

[0668] 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)

[0669] [Comparative Example 5]

[0670] According to the method described in Patent Document 4, a compound represented by the following formula (ZE) was synthesized.

[0671]

[0672] (Rf1 in formula (ZE) is the PFPE chain represented by the above formula (4-1). In Rf1, h representing the average degree of polymerization is 4.5, and i representing the average degree of polymerization is 4.5.)

[0673] The number average molecular weight (Mn) of the compounds of Examples 1 to 38 and Comparative Examples 1 to 5 obtained in this manner was measured by the above-mentioned method. The results are shown in Tables 3 and 4.

[0674] Next, a lubricant layer forming solution was prepared by the method described below using the compounds obtained in Examples 1 to 38 and Comparative Examples 1 to 5. Furthermore, the lubricant layer of a magnetic recording medium was formed by the method described below using the obtained lubricant layer forming solution, thereby obtaining magnetic recording media of Examples 1 to 38 and Comparative Examples 1 to 5.

[0675] "Lubricating layer forming solution"

[0676] The compounds obtained in Examples 1 to 38 and Comparative Examples 1 to 5 were dissolved in a fluorine-based solvent, Batorel (registered trademark) XF (trade name, manufactured by Mitsui Dupont Fluoro Chemical Co., Ltd.), respectively, to form a film having a thickness of 100% to 100% when applied on the protective layer. The solution was diluted with Batler XF in a manner of 100% to prepare a lubricating layer forming solution.

[0677] "Magnetic recording media"

[0678] 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 formed of carbon.

[0679] On the protective layer of the magnetic recording medium formed with each layer up to the protective layer, the lubricating layer forming solutions of Examples 1 to 38 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.

[0680] Then, the magnetic recording medium coated with the lubricating layer forming solution is added to a constant temperature bath and heat treated at 120°C for 10 minutes to remove the solvent in the lubricating layer forming solution and 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.

[0681] [Film thickness measurement]

[0682] The film thickness of the lubricating layer of the magnetic recording media of Examples 1 to 38 and Comparative Examples 1 to 5 obtained in this manner was measured using a Fourier transform infrared spectrophotometer (FT-IR, trade name: Nicolet iS50, manufactured by Thermo Fisher Scientific).

[0683] Next, the magnetic recording media of Examples 1 to 38 and Comparative Examples 1 to 5 were subjected to the following corrosion resistance test and peeling characteristic test. The results are shown in Tables 3 and 4.

[0684] [Corrosion resistance test]

[0685] The magnetic recording medium was exposed to the conditions of 85°C and 90% relative humidity for 48 hours. Then, an optical surface analyzer (Candela 7140 manufactured by Kellner Tencore Co., Ltd.) was used to count the number of corrosion spots with a diameter of 5 μm or more generated on the surface of the magnetic recording medium, and the evaluation was performed based on the following evaluation criteria.

[0686] "Evaluation criteria for corrosion resistance"

[0687] A+: The number of corrosion points is less than 100

[0688] A: The number of corrosion points is more than 100 and less than 300

[0689] B: The number of corrosion points is more than 300 and less than 500

[0690] C: The number of corrosion points is 500 or more and less than 1000

[0691] D: The number of corrosion points is more than 1000

[0692] [Shedding characteristics test]

[0693] The magnetic recording medium was mounted on a spin stand and rotated at a speed of 10,000 rpm for 72 hours at 80°C. Before and after this operation, the thickness of the lubricating layer at a position with a radius of 20 mm from the center of the magnetic recording medium was measured using FT-IR, and the thickness reduction rate of the lubricating layer before and after the test was calculated. Using the calculated thickness reduction rate, the shedding characteristics were evaluated according to the evaluation criteria shown below.

[0694] "Evaluation criteria for shedding characteristics"

[0695] A+: Film thickness reduction rate is less than 2%

[0696] A: Film thickness reduction rate is 2% or more and less than 3%

[0697] B: Film thickness reduction rate is 3% or more and less than 5%

[0698] C: Film thickness reduction rate is 5% or more and less than 10%

[0699] D: Film thickness reduction rate is more than 10%

[0700] [Comprehensive evaluation]

[0701] From the results of the corrosion resistance test and the peeling property test, comprehensive evaluation was performed based on the following criteria.

[0702] “Comprehensive Evaluation Criteria”

[0703] A: Both the evaluation of the corrosion resistance test and the evaluation of the shedding characteristics test are A+ or A

[0704] B: One of the evaluations in the corrosion resistance test and the peeling characteristics test is B, and the other is A+, A, or B

[0705] C: One of the evaluations in the corrosion resistance test and the peeling characteristics test is C, and the other is A+, A, B, or C

[0706] D: At least one of the evaluation in the corrosion resistance test and the evaluation in the peeling property test was D [Table 3]

[0707] Table 3

[0708]

[0709] [Table 4]

[0710] Table 4

[0711]

[0712] As shown in Tables 3 and 4, R 1 and R 3 At least one of them is the terminal group represented by formula (2), and the magnetic recording media of Examples 1 to 38 of the fluorinated ether compounds (AA) to (AS), (BA) to (BH), (CA) to (CK) satisfying formula (1) are all evaluated as A+, A, or B in the corrosion resistance test and the shedding characteristic test, and the comprehensive evaluation is A or B. Therefore, it can be confirmed that the lubricating layer of the magnetic recording media of Examples 1 to 38 has good corrosion resistance and can suppress shedding.

[0713] When using R 1 and R 3In Examples 8, 9, 15 to 18, 35, 36, and 38 of compounds (AH), (AI), (AO) to (AR), (CH), (CI), and (CK) having terminal groups represented by formulas (2-3), (2-5), (2-6), and (2-7), the evaluation of the corrosion resistance test was A+, showing good results.

[0714] When using R 1 and R 3 Compounds (AA), (AB), (AD), (BG), (BH), (CA), R 1 and R 3 Compounds (AE), (AF), (CB), (CC), (CD), R wherein the terminal group is represented by formula (2-2) and c is 3 or less 1 and R 3 Compounds (AJ) to (AM), (CE), (CJ), R wherein the terminal group is represented by formula (2-4) and e is 2 or less 1 and R 3 A compound (AS) wherein one of the compounds is a terminal group represented by formula (2-1) and the sum of a and b is 4 or less, and the other is a terminal group represented by formula (2-2) and c is 3 or less, R 1 and R 2 In Examples 1, 2, 4 to 6, 10 to 13, 19, 26 to 34 and 37 of compounds (CF) and (CG) having terminal groups represented by formula (2-7) and g2 being 3 or less, the evaluation of the shedding property test was A+, which was good.

[0715] On the other hand, as shown in Tables 3 and 4, in Comparative Examples 1 to 5 using compounds (ZA) to (ZE), all evaluations of the corrosion resistance test and the peeling property test were B, C, and D, and the comprehensive evaluation was C or D.

[0716] In the compound (ZA) used in Comparative Example 1, the terminal group does not include a 1,2-diol structure and a carbon atom that is not bonded to a polar group or an ether oxygen atom.

[0717] The terminal group of compound (ZA) does not contain a 1,2-diol structure, and all hydroxyl groups contribute greatly to increasing the polarity of the entire molecule. In addition, since the terminal group of compound (ZA) does not contain a carbon atom that is not bonded to a polar group or an ether oxygen atom, the hydrophobicity of the molecule cannot be fully obtained. Based on these circumstances, it can be considered that in Comparative Example 1, the fluorinated ether compound is easy to introduce water that is the cause of corrosion, and the result of the corrosion resistance test is D.

[0718] For compound (ZA), since the distance between hydroxyl groups is farther than that between hydroxyl groups in the 1,2-diol structure, all hydroxyl groups are likely to interact with the protective layer. As a result, it is believed that since the interaction between hydroxyl groups between molecules becomes smaller, the lubricant is likely to scatter with the rotation of the magnetic recording medium, and the evaluation of the shedding characteristic test becomes C.

[0719] The compound (ZB) used in Comparative Example 2 and the compound (ZC) used in Comparative Example 3 have terminal groups containing carbon atoms that are not bonded to polar groups or ether oxygen atoms, but do not contain a 1,2-diol structure.

[0720] Since the terminal groups of compounds (ZB) and (ZC) contain carbon atoms that are not bonded to polar groups or ether oxygen atoms, the hydrophobicity of the molecules becomes high. In addition, the total number of hydroxyl groups possessed by compounds (ZB) and (ZC) is 4. Therefore, the total number of hydroxyl groups possessed by compounds (ZB) and (ZC) is less than the total number of hydroxyl groups possessed by compound (ZA) used in Comparative Example 1, which is 6. Therefore, for compounds (ZB) and (ZC), fluorine-containing ether compounds are not easily introduced into water that is a cause of corrosion, and the results of the corrosion resistance test of Comparative Examples 2 and 3 are better than those of Comparative Example 1.

[0721] For compounds (ZB) and (ZC), since the distance between hydroxyl groups is farther than that between hydroxyl groups in the 1,2-diol structure, all hydroxyl groups are likely to interact with the protective layer. In addition, since the total number of hydroxyl groups in compounds (ZB) and (ZC) is 4, which is relatively small, there are almost no hydroxyl groups that can contribute to the interaction between molecules. As a result, it can be considered that the intermolecular interaction of the fluorinated ether compound is small, and the lubricant is likely to scatter with the rotation of the magnetic recording medium, and the evaluation of the shedding characteristic test of Comparative Examples 2 and 3 is D.

[0722] The compound (ZD) used in Comparative Example 4 and the compound (ZE) used in Comparative Example 5 have a 1,2-diol structure at the terminal group, but do not contain a carbon atom that is not bonded to a polar group or an ether oxygen atom.

[0723] Since compounds (ZD) and (ZE) do not contain a carbon atom that is not bonded to a polar group or an ether oxygen atom in the terminal group, the hydrophobicity of the molecule is reduced. As a result, it is considered that the fluorine-containing ether compound is easy to take in water that is a cause of corrosion, and the result of the corrosion resistance test in Comparative Example 4 is C, and the result of the corrosion resistance test in Comparative Example 5 is D. The reason why the result of the corrosion resistance test is C in Comparative Example 4 and D in Comparative Example 5 is considered to be because the total number of hydroxyl groups possessed by compound (ZD) is 4, and the total number of hydroxyl groups possessed by compound (ZE) is 8, and therefore water is more easily taken in in Comparative Example 5 having a larger total number of hydroxyl groups.

[0724] Since compounds (ZD) and (ZE) do not contain carbon atoms that are not bound to polar groups and ether oxygen atoms at the ends, it is not easy to give appropriate rigidity to the molecules. Therefore, the two hydroxyl groups that constitute the 1,2-diol structure are easy to interact with each other within the molecule. As a result, it can be considered that since the hydroxyl groups in the fluorinated ether compound are not easy to interact with each other between molecules, the lubricant is easy to scatter with the rotation of the magnetic recording medium, so the evaluation of the shedding characteristic test of Comparative Examples 4 and 5 becomes C.

[0725] Industrial Availability

[0726] 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 corrosion resistance and is prevented from coming off even if the lubricating layer is thin.

[0727] Explanation of symbols

[0728] 10 Magnetic recording media

[0729] 11 substrate

[0730] 12 Adhesion layer

[0731] 13Soft magnetic layer

[0732] 141st base layer

[0733] 15 Second basal layer

[0734] 16 Magnetic layer

[0735] 17 protective layers

[0736] 18 Lubrication layer.

Claims

1. A fluorine-containing ether compound, characterized in that It is represented by the following formula (1): R 1 -CH2-R 2 -CH2-R 3 (1) In formula (1), R 2 is a perfluoropolyether chain; R 1 and R 3 is a terminal group having 1 to 4 polar groups and 1 to 50 carbon atoms; R 1 and R 3 Can be the same or different; R 1 and R 3 At least one of them is a terminal group represented by the following formula (2); -OX-CH(OH)-CH2OH (2) In formula (2), X is a divalent organic group having 2 to 30 carbon atoms which may contain at least one of 1 to 2 polar groups and 1 to 3 ether oxygen atoms; X contains at least one carbon atom which is not bonded to either a polar group or an ether oxygen atom.

2. The fluorinated ether compound according to claim 1, wherein the terminal group represented by the formula (2) is any one of the following formulas (2-1) to (2-7), In formula (2-1), a represents an integer from 1 to 8; b represents an integer from 1 to 7; In formula (2-2), c represents an integer from 1 to 7; In formula (2-3), d represents an integer from 1 to 6; In formula (2-4), e represents an integer from 1 to 6; e R a and R b each independently represents a hydrogen atom or a methyl group; In formula (2-5), f represents an integer from 1 to 6; In formula (2-6), g represents an integer from 1 to 6; In formula (2-7), g2 represents an integer of 1 to 6.

3. The fluorinated ether compound according to claim 1 or 2, wherein R in the formula (1) 1 and R 3 Each is independently a terminal group represented by the above formula (2).

4. The fluorinated ether compound according to claim 1 or 2, wherein R in the formula (1) 1 and R 3 same.

5. The fluorinated ether compound according to claim 1 or 2, wherein R in the formula (1) 1 and R 3 One of them is a terminal group represented by the above formula (2), and the other is a terminal group represented by the following formula (3) and not conforming to formula (2), In formula (3), l represents an integer of 1 to 3; l m each independently represents an integer of 1 to 6; l n each independently represents an integer of 1 to 6; in one repeating unit, at least one of m and n is 1; B represents an alkyl group which may have only one polar group, an organic group containing a carbon-carbon unsaturated bond, or a hydrogen atom.

6. The fluorinated ether compound according to claim 1 or 2, wherein R in the formula (1) 1 and R 3 One of them is a terminal group represented by the above formula (2), and the other is a terminal group represented by any one of the following formulas (3-1) to (3-3), In formula (3-1), p represents an integer of 0 to 3; q represents an integer of 0 to 2; r represents an integer of 0 to 5; the total value of p and r is 1 to 5; D represents a polar group, a vinyl group, an ethynyl group, or an aromatic group which may have a substituent; In formula (3-2), s represents an integer from 0 to 2; t represents an integer from 1 to 5; In formula (3-3), u represents an integer of 1 to 3; 5 E's each independently represent a polar group, an alkoxy group having 1 to 8 carbon atoms, a halogenated group, or a hydrogen atom; wherein, When the five E's contain a polar group, the number of polar groups in the five E's is one.

7. The fluorinated ether compound according to claim 1 or 2, wherein R in the formula (1) 1 and R 3 The total number of polar groups possessed is 4 to 6.

8. The fluorinated ether compound according to claim 1 or 2, wherein R in the formula (1) 2 is a perfluoropolyether chain represented by the following formula (4), -(CF2) w1 -O-(CF2O) w2 -(CF2CF2O) w3 -(CF2CF2CF2O) w4 -(CF2CF2CF2CF2O) w5 -(CF2) w6 -(4) In formula (4), w2, w3, w4, and w5 represent average polymerization degrees, and each independently represents 0 to 20; wherein, w2, w3, w4, and w5 are not all 0 at the same time; w1 and w6 are average values ​​of the number of CF2, and each independently represents 1 to 3; there is no particular restriction on the arrangement order of (CF2O), (CF2CF2O), (CF2CF2CF2O), and (CF2CF2CF2CF2O) as repeating units in formula (4).

9. The fluorinated ether compound according to claim 1 or 2, wherein R in the formula (1) 2 is any one selected from the perfluoropolyether chains represented by the following formulae (4-1) to (4-4), -CF2-(OCF2CF2) h -(OCF2) i -OCF2- (4-1) In formula (4-1), h and i represent the average degree of polymerization, h represents 1 to 20, and i represents 0 to 20; -CF2CF2-(OCF2CF2CF2) j -OCF2CF2- (4-2) In formula (4-2), j represents the average degree of polymerization and is 1 to 15; -CF2CF2CF2-(OCF2CF2CF2CF2) k -OCF2CF2CF2- (4-3) In formula (4-3), k represents the average degree of polymerization and is 1 to 10; -(CF2) w7 -O-(CF2CF2CF2O) w8 -(CF2CF2O) w9 -(CF2) w10 - (4-4) In formula (4-4), w8 and w9 represent average polymerization degrees, and each independently represents 1 to 20; w7 and w10 represent average values ​​of the number of CF2, and each independently represents 1 to 2.

10. The fluorine-containing ether compound according to claim 1 or 2, which has a number average molecular weight in the range of 500 to 10,000.

11. A lubricant for a magnetic recording medium, characterized in that: Contains the fluorine-containing ether compound according to claim 1 or 2.

12. A magnetic recording medium, characterized in that: A magnetic recording medium comprising at least a magnetic layer, a protective layer, and a lubricating layer provided in this order on a substrate, wherein the lubricating layer comprises the fluorine-containing ether compound according to claim 1 or 2. 13 . The magnetic recording medium according to claim 12 , wherein the lubricating layer has an average film thickness of 0.5 nm to 2.0 nm.

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