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

Abstract

The fluorine-containing ether compound is a fluorine-containing ether compound represented by the following formula. R < 1 >-CH < 2 >-R < 2 >-(CH < 2 >-R < 3 >-CH < 2 >-R < 4 > (z is 1 or 2). And R2 is a perfluoropolyether chain. And R1 is represented by formula (2). And R4 represents an organic group having 1-3 polar groups and having 3-35 carbon atoms. And R3 is represented by formula (4). > # imgabs0 #

Description

Technical Field

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

[0002] This application claims priority based on Japanese Patent Application No. 2023-071338 filed in Japan on April 25, 2023, the contents of which are incorporated herein by reference. Background Art

[0003] In order to increase the recording density in a magnetic recording and reproducing device, the development of a magnetic recording medium suitable for high recording density has been progressing.

[0004] In the past, as a magnetic recording medium, there is a recording layer formed on a substrate, and a protective layer formed by 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. In addition, the protective layer covers the recording layer to prevent the metal contained in the recording layer from being corroded by environmental substances.

[0005] However, only by arranging a protective layer on the recording layer, the durability of the magnetic recording medium cannot be fully obtained. Therefore, a lubricant is applied to the surface of the protective layer to form a lubricating layer. For the outermost lubricating layer configured on the magnetic recording medium, in addition to improving the durability and protection of the protective layer, it is also required to improve the floating stability and wear resistance of the magnetic head.

[0006] As a lubricant used in forming a lubricating layer of a magnetic recording medium, a lubricant containing a compound having a polar group such as a hydroxyl group at the end of a fluorine-based polymer having a repeating structure containing -CF2- has been proposed (for example, see Patent Documents 1 to 6).

[0007] Patent Documents 1 to 4 disclose fluorinated ether compounds having a skeleton in which a plurality of perfluoropolyether chains are linked via a linking group having a secondary hydroxyl group, and terminal groups having polar groups are linked to both sides of the skeleton via a methylene group (-CH2-).

[0008] Patent Document 5 discloses a method for producing a polyol perfluoropolyether compound useful as a lubricant for magnetic media. Patent Document 5 describes a method for producing a polyol (per)fluoropolyether derivative by reacting a triol with an activator to synthesize an activated protected triol, and then reacting the triol with hydroxyl groups disposed at both ends of a functional (per)fluoropolyether to undergo a nucleophilic substitution reaction.

[0009] Patent Document 6 discloses a fluorine-containing ether compound including one perfluoropolyether chain in the molecule and having terminal groups each including two primary hydroxyl groups bonded to both sides of the perfluoropolyether chain.

[0010] Prior art literature

[0011] Patent Literature

[0012] Patent Document 1: International Publication No. 2021 / 251335

[0013] Patent Document 2: International Publication No. 2016 / 084781

[0014] Patent Document 3: U.S. Patent Application Publication No. 2016 / 0260452

[0015] Patent Document 4: International Publication No. 2018 / 116742

[0016] Patent Document 5: Japanese Patent No. 5334064

[0017] Patent Document 6: International Publication No. 2022 / 131202 Summary of the invention

[0018] Problems to be solved by the invention

[0019] The development progress of magnetic recording medium suitable for high recording density is directed to the large capacity of magnetic recording and reproducing devices. In recent years, the recording density of magnetic recording media has been improved, and it is required to make the distance between the magnetic head and the magnetic layer of the magnetic recording medium shorter and reduce the magnetic spacing (flying height). Therefore, it is required to make the thickness of the protective layer and / or lubricating layer in the magnetic recording medium thinner.

[0020] However, generally speaking, if the thickness of the lubricating layer is reduced, the coating property of the lubricating layer is reduced, and the wear resistance and smoothness of the magnetic recording medium tend to be reduced.

[0021] 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 wear resistance and good smoothness and can be suitably used as a material for a lubricant for a magnetic recording medium.

[0022] Another object of the present invention is to provide a lubricant for a magnetic recording medium which can form a lubricating layer comprising the fluorinated ether compound of the present invention and having excellent wear resistance and good smoothness.

[0023] Another 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 and having excellent wear resistance and good smoothness.

[0024] Means for solving problems

[0025] The present inventors have conducted intensive studies to solve the above-mentioned problems.

[0026] As a result, it was found that the following fluorine-containing ether compound can be prepared, which has the following skeleton, that is, a skeleton having two or three perfluoropolyether chains, a divalent connecting group having only one secondary hydroxyl group bonded between adjacent perfluoropolyether chains via a methylene group (-CH2-), and a specific branched terminal group consisting of an organic group having 3 to 35 carbon atoms and two groups containing no secondary hydroxyl group and one primary hydroxyl group bonded to a trisubstituted carbon atom is arranged at at least one end of the skeleton via a methylene group, and when only one end is the above-mentioned branched terminal group, an organic group having 3 to 35 carbon atoms and having 1 to 3 polar groups is arranged at the other end via a methylene group.

[0027] That is, the present invention relates to the following matters.

[0028] [1] A fluorine-containing ether compound characterized by being represented by the following formula (1).

[0029] R 1 -CH2-R 2 -(CH2-R 3 -CH2-R 2 ) z -CH2-R 4 (1)

[0030] (In formula (1), z is 1 or 2. R 2 is a perfluoropolyether chain. (z+1) R 2 Some or all of them may be the same, or they may be different. 1 It is a branched terminal group having 3 to 35 carbon atoms represented by the following formula (2). 4 is an organic group having 3 to 35 carbon atoms and having 1 to 3 polar groups, and R 1 Can be the same or different. 3 is a divalent linking group represented by the following formula (4). When z is 2, the two R 3 Can be the same or different.)

[0031]

[0032] (In formula (2), R 5 and R 6 It is an organic group that does not contain a secondary hydroxyl group or a tertiary hydroxyl group but contains one primary hydroxyl group, and they may be the same or different. x is an integer of 0 to 3.

[0033] (In formula (4), h is an integer from 1 to 3, and i is an integer from 1 to 3.)

[0034] [2] The fluorine-containing ether compound according to [1], wherein the above formula (2) is any one of the following formulas (2-1) and (2-2).

[0035]

[0036] (In formula (2-1), a is an integer of 1 to 3, and b is an integer of 1 to 4. 1 is a hydrogen atom or a group represented by formula (3). 2 is a group represented by formula (3). 1 With X 2 Can be the same or different.)

[0037] (In formula (2-2), c is an integer of 0 to 3, and d and e are each independently an integer of 1 to 5. 3 and X 4 Each independently represents a hydrogen atom or a group represented by formula (3). 3 With X 4 Can be the same or different.)

[0038] (In formula (3), f is an integer of 2 to 5, and g is 1 or 2.)

[0039] [3] The fluorinated ether compound according to [1] or [2], wherein R in the formula (1) 4 It is a group represented by the above formula (2).

[0040] [4] The fluorinated ether compound according to [2], wherein R in the above formula (1) 1 and R 4 Both are independently represented by the above formula (2-1) or formula (2-2).

[0041] [5] The fluorinated ether compound according to any one of [1] to [4], wherein in the above formula (1), R 1 and R 4 same.

[0042] [6] The fluorinated ether compound according to [1] or [2], wherein R in the formula (1) 4 It is any group represented by the following formula (6-1) to formula (6-3).

[0043]

[0044] (In formula (6-1), y1 is 1 or 2, and y2 is an integer from 0 to 3. 5 is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, an alkynyl group, or a polar group. 5 is a polar group. 5When X is an aromatic hydrocarbon group or an unsaturated heterocyclic group, 5 The atoms in the ring structure are bound to X 5 Adjacent methylene groups. 5 When it is an alkenyl group or an alkynyl group, X 5 The unsaturated carbon atom in the bond is bonded to X 5 adjacent methylene groups. )

[0045] (In formula (6-2), y3 is an integer from 1 to 3, y4 is 0 or 1, and y5 is an integer from 0 to 3. 5 is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, an alkynyl group, or a polar group. 5 is a polar group. 5 When X is an aromatic hydrocarbon group or an unsaturated heterocyclic group, 5 The atoms in the ring structure are bound to X 5 Adjacent methylene groups. 5 When it is an alkenyl group or an alkynyl group, X 5 The unsaturated carbon atom in the bond is bonded to X 5 adjacent methylene groups. )

[0046] (In formula (6-3), y6 is 0 or 1, y7 is an integer from 1 to 3, and y8 is an integer from 1 to 3. 5 is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, an alkynyl group, or a polar group. 5 is a polar group. 5 When X is an aromatic hydrocarbon group or an unsaturated heterocyclic group, 5 The atoms in the ring structure are bound to X 5 Adjacent methylene groups. 5 When it is an alkenyl group or an alkynyl group, X 5 The unsaturated carbon atom in the bond is bonded to X 5 adjacent methylene groups. )

[0047] [7] The fluorinated ether compound according to any one of [1] to [6], wherein the (z+1)th R in the formula (1) 2 Each is independently a perfluoropolyether chain represented by the following formula (5).

[0048] -(CF2) w1 -O-(CF2O) w2 -(CF2CF2O) w3 -(CF2CF2CF2O) w4 -(CF2CF2CF2CF2O) w5 -(CF2) w6 - (5)

[0049] (In formula (5), 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 (5).)

[0050] [8] The fluorinated ether compound according to any one of [1] to [7], wherein the (z+1)th R in the formula (1) 2 Each independently represents any one selected from the group consisting of perfluoropolyether chains represented by the following formula (5-1) to (5-4).

[0051] -CF2-(OCF2CF2) j -(OCF2) k -OCF2-(5-1)

[0052] (In formula (5-1), j and k represent average polymerization degrees, j represents 1 to 20, and k represents 0 to 20.)

[0053] -CF2CF2-(OCF2CF2CF2) l -OCF2CF2-(5-2)

[0054] (In formula (5-2), l represents the average degree of polymerization and is 1 to 15.)

[0055] -CF2CF2CF2-(OCF2CF2CF2CF2) m -OCF2CF2CF2-(5-3)

[0056] (In formula (5-3), m represents the average degree of polymerization and is 1 to 10.)

[0057] -(CF2) w7 -O-(CF2CF2CF2O) w8 -(CF2CF2O) w9 -(CF2) w10 -(5-4)

[0058] (In formula (5-4), 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 groups, and each independently represents 1 to 2.)

[0059] [9] The fluorinated ether compound according to any one of [1] to [8], wherein the (z+1)th R in the formula (1)2 All the same.

[0060]

[10] The fluorinated ether compound according to any one of [1] to [9], wherein the number average molecular weight is within the range of 500 to 10,000.

[0061]

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

[10] .

[0062]

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

[0063] The lubricating layer contains the fluorine-containing ether compound described in any one of [1] to

[10] .

[0064]

[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.

[0065] Effects of the Invention

[0066] The fluorine-containing ether compound of the present invention is a compound represented by the above formula (1), and is suitable as a material for a lubricant for a magnetic recording medium.

[0067] 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 having excellent wear resistance and smoothness even if the lubricating layer is thin.

[0068] The magnetic recording medium of the present invention has a lubricating layer containing the fluorine-containing ether compound of the present invention and having excellent wear resistance and smoothness. Therefore, the magnetic recording medium of the present invention has excellent reliability and durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 This is a schematic cross-sectional view showing one embodiment of the magnetic recording medium of the present invention. DETAILED DESCRIPTION

[0070] In order to solve the above-mentioned problems, the present inventors paid attention to the relationship between the molecular structure of the fluorinated ether compound contained in the lubricant and the protective layer, and conducted intensive studies as shown below.

[0071] Conventionally, fluorine-containing ether compounds having a polar group such as a hydroxyl group have been used as materials for a lubricant for a magnetic recording medium (hereinafter, sometimes simply referred to as a "lubricant") to be applied to the surface of a protective layer.

[0072] As the fluorinated ether compound having a polar group, there is a fluorinated ether compound having a terminal group having a plurality of polar groups arranged at the end of the chain structure. In addition, as the fluorinated ether compound, there is a fluorinated ether compound having a plurality of perfluoropolyether chains, and a linking group having a polar group arranged between adjacent perfluoropolyether chains. In the lubricating layer containing the fluorinated ether compound, the polar group contained in the fluorinated ether compound is combined with the active point on the protective layer, so that the adhesion of the lubricating layer to the protective layer is improved.

[0073] However, for the lubricating layer containing the conventional fluorinated ether compound, even when the lubricating layer is formed by using the fluorinated ether compound having a plurality of polar groups in the molecule, sometimes the adhesion to the protective layer cannot be fully obtained. As a method for improving the adhesion of the lubricating layer to the protective layer, it is considered to use a fluorinated ether compound having a greater number of polar groups. However, for the lubricating layer formed by using such a fluorinated ether compound, sometimes the smoothness and wear resistance of the magnetic recording medium cannot be fully obtained.

[0074] Therefore, the present inventors have focused on the bonding between the polar groups contained in the fluorine-containing ether compound and the active sites on the protective layer and have conducted intensive studies.

[0075] As a result, it was found that the following fluorine-containing ether compound can be prepared. The above fluorine-containing ether compound has the following skeleton as shown in the above formula (1), that is, a skeleton having two or three perfluoropolyether chains, a skeleton having a divalent linking group represented by the above formula (4) having only one secondary hydroxyl group bonded between adjacent perfluoropolyether chains via a methylene group (-CH2-), a branched terminal group represented by the above formula (2) consisting of an organic group having 3 to 35 carbon atoms arranged via a methylene group at at least one end of the skeleton, and two groups including one primary hydroxyl group and not including a secondary hydroxyl group and a tertiary hydroxyl group are bonded to a trisubstituted carbon atom; and when only one end is the branched terminal group represented by the above formula (2), an organic group having 3 to 35 carbon atoms and having 1 to 3 polar groups is arranged via a methylene group at the other end.

[0076] It is estimated that the lubricating layer containing the fluorine-containing ether compound represented by the above formula (1) has good smoothness and excellent wear resistance due to the synergistic effect of the following actions and functions.

[0077] The secondary hydroxyl group contained in the fluorinated ether compound represented by the above formula (1), the secondary hydroxyl group possessed by the linking group represented by the formula (4), and the primary hydroxyl group possessed by the branched terminal group represented by the formula (2) are easily involved in the bonding with the active sites present in the protective layer due to the reasons shown below <1> to <3>.

[0078] <1> For the fluorinated ether compound represented by formula (1), a divalent linking group represented by formula (4) having only one secondary hydroxyl group is bonded between two or three perfluoropolyether chains. Therefore, for example, when there are two divalent linking groups represented by formula (4), the perfluoropolyether chains are arranged between the divalent linking groups. Therefore, even if there are two divalent linking groups represented by formula (4), the distance between the secondary hydroxyl groups will not become too close. Therefore, even if there are two divalent linking groups represented by formula (4), the two secondary hydroxyl groups will not hinder the bonding with the active points on the protective layer due to the adjacent secondary hydroxyl groups.

[0079] In addition, for the fluorine-containing ether compound shown in formula (1), a perfluoropolyether chain is respectively arranged between the divalent linking group shown in formula (4) and the two terminal groups. Therefore, the distance between the secondary hydroxyl group contained in the divalent linking group shown in formula (4) and the polar groups contained in the two terminal groups will not become too close. As a result, the secondary hydroxyl group contained in the divalent linking group shown in formula (4) will not be hindered from binding with the active points on the protective layer by the polar groups contained in the two terminal groups. Therefore, the secondary hydroxyl group contained in the divalent linking group shown in formula (4) is easy to participate in the binding with the active points on the protective layer.

[0080] <2> For the fluorine-containing ether compound represented by formula (1), a perfluoropolyether chain is respectively arranged between the divalent linking group represented by formula (4) and the two terminal groups. Therefore, the secondary hydroxyl group contained in the divalent linking group represented by formula (4) will not hinder the binding of the polar groups contained in the two terminal groups with the active points on the protective layer, and the secondary hydroxyl group contained in the divalent linking group represented by formula (4) is not easy to agglomerate with the polar groups contained in each terminal group. Therefore, for the fluorine-containing ether compound represented by formula (1), not only the secondary hydroxyl group contained in the above-mentioned divalent linking group, but also the polar groups contained in each terminal group are easy to bind to the active points on the protective layer.

[0081] <3> At least one terminal group is a branched terminal group represented by formula (2) in which two organic groups including one primary hydroxyl group are bonded to a trisubstituted carbon atom, and the distance between the two primary hydroxyl groups included in formula (2) is appropriate. Therefore, for the fluorine-containing ether compound represented by formula (1), aggregation caused by the distance between the two primary hydroxyl groups included in the branched terminal group represented by formula (2) being too close is not likely to occur, and the two primary hydroxyl groups do not hinder each other from bonding to the active points on the protective layer.

[0082] In addition, since the branched terminal group shown in the above formula (2) is an organic group having 3 to 35 carbon atoms, the distance between the two primary hydroxyl groups contained in the branched terminal group will not be too far. Therefore, if one of the primary hydroxyl groups contained in the branched terminal group shown in formula (2) is bonded to the protective layer, the distance between the other primary hydroxyl group and the protective layer also becomes closer. As a result, the other primary hydroxyl group can form an orientation that easily induces adsorption to the protective layer. Therefore, the two primary hydroxyl groups contained in the branched terminal group shown in formula (2) are easy to simultaneously bond to the active points on the protective layer.

[0083] Moreover, in the branched terminal group shown in formula (2), two organic groups containing one primary hydroxyl group without secondary hydroxyl group and tertiary hydroxyl group are bonded to the trisubstituted carbon atom. Therefore, for example, compared with the periphery of the secondary hydroxyl group bonded to the carbon atom forming the chain structure of the fluorine-containing ether compound, the periphery of the two primary hydroxyl groups contained in the branched terminal group shown in formula (2) is sterically empty. In addition, since the two organic groups containing one primary hydroxyl group are bonded to the trisubstituted carbon atom, the distance between the two primary hydroxyl groups and the adjacent perfluoropolyether chain is appropriate. Therefore, the two primary hydroxyl groups are not easily hindered from bonding to the active points on the protective layer due to the adjacent perfluoropolyether chain, which is a bulky part of the fluorine-containing ether compound shown in formula (1), and the trisubstituted carbon atom in the branched terminal group shown in formula (2).

[0084] Furthermore, primary hydroxyl groups generally have a high degree of freedom and can move freely compared to secondary hydroxyl groups and tertiary hydroxyl groups. Therefore, the two primary hydroxyl groups contained in the branched terminal group shown in formula (2) can move spontaneously relative to the active points on the protective layer. Therefore, the two primary hydroxyl groups contained in the branched terminal group can easily form a bond with the active points on the protective layer.

[0085] Due to the reasons of <1> to <3> above, the secondary hydroxyl groups contained in the linking group represented by formula (4) and the primary hydroxyl groups contained in the branched terminal group represented by formula (2) contained in the fluorinated ether compound represented by formula (1) are easy to participate in the bonding with the active points existing on the protective layer. Therefore, the lubricating layer comprising the fluorinated ether compound represented by formula (1) is closely attached to the protective layer through the secondary hydroxyl groups contained in the linking group represented by formula (4) disposed between adjacent perfluoropolyether chains and the two primary hydroxyl groups contained in the branched terminal group represented by formula (2) disposed at at least one end, and has good adhesion to the protective layer.

[0086] Moreover, the lubricating layer comprising the fluorinated ether compound represented by formula (1) has moderate flexibility due to the bonding to the adjacent methylene group through an ether bond, since the end of the branched terminal group represented by formula (2) that is bonded to the adjacent methylene group is an oxygen atom. Furthermore, the lubricating layer comprising the fluorinated ether compound represented by formula (1) has sufficient fluidity and flexibility due to the high mobility of the two primary hydroxyl groups contained in the branched terminal group represented by formula (2). Based on these circumstances, the lubricating layer comprising the fluorinated ether compound represented by formula (1) has very good adhesion to the protective layer.

[0087] In this way, the fluorinated ether compound represented by formula (1) can form a lubricating layer with good adhesion to the protective layer, and the perfluoropolyether chain in the fluorinated ether compound contained in the lubricating layer is not too far away from the protective layer, and a structure that is closely attached to the protective layer can be formed. Therefore, the state on the protective layer is not easy to become large, and a lubricating layer with suppressed surface unevenness is obtained, and it is easy to wet and expand on the protective layer, and a lubricating layer with good coating properties with a uniform coating state can be formed. As a result, it is estimated that the fluorinated ether compound represented by formula (1) can form a lubricating layer with excellent wear resistance and good smoothness.

[0088] Furthermore, since the lubricating layer containing the fluorinated ether compound represented by formula (1) has sufficient fluidity and softness, even if a part of the lubricating layer is deformed by wear, the fluorinated ether compound in the lubricating layer moves to another position, and the restoring power to the original position is high. Therefore, it is estimated that the lubricating layer containing the fluorinated ether compound represented by formula (1) has better smoothness and obtains excellent wear resistance.

[0089] In contrast, for example, if there is a polar group in the fluorinated ether compound that does not participate in the combination with the active point on the protective layer, the adhesion between the lubricating layer and the protective layer becomes insufficient. As a result, the fluorinated ether compounds contained in the lubricating layer are locally agglomerated with each other, or part of the molecules of the fluorinated ether compound float from the surface of the protective layer, forming concave and convex surfaces on the surface of the lubricating layer. Therefore, the state of the lubricant in the lubricating layer becomes large volume, the coating state of the lubricating layer on the protective layer becomes uneven, and it is not easy to obtain a lubricating layer with good coating and smoothness. In addition, if the adhesion between the lubricating layer and the protective layer is insufficient, the state of the lubricating layer existing on the surface of the magnetic recording medium will change due to the high-speed rotation of the magnetic recording medium, the wear resistance of the lubricating layer will be reduced, and the durability and reliability of the magnetic recording medium will be reduced.

[0090] Specifically, for example, in the case where a divalent linking group having two or more secondary hydroxyl groups is configured instead of the divalent linking group shown in formula (4) having only one secondary hydroxyl group, the two or more secondary hydroxyl groups possessed by the divalent linking group are likely to hinder each other from binding to the active points on the protective layer. Therefore, at least a portion of the two or more secondary hydroxyl groups are likely to become polar groups that do not participate in the binding to the active points on the protective layer, and sometimes the polar groups that do not participate in the binding to the active points on the protective layer induce polar groups between molecules and / or within molecules, thereby becoming fluorine-containing ether compounds that are easy to agglomerate. Therefore, in the case where a divalent linking group having two or more secondary hydroxyl groups is configured instead of the divalent linking group shown in formula (4), it is not easy to form a lubricating layer with good wear resistance and smoothness.

[0091] Furthermore, the present inventors have confirmed that a lubricating layer having excellent wear resistance and good smoothness can be formed by forming a lubricating layer on a protective layer of a magnetic recording medium using a lubricant containing the above-mentioned fluorinated ether compound, and thus have arrived at the present invention.

[0092] Below, fluorine-containing ether compound of the present invention, lubricant for magnetic recording medium and magnetic recording medium are described in detail. In addition, the present invention is not limited only to the embodiment shown below. The present invention can add, omit, replace, change number, amount, ratio, composition, kind, position, material, formation etc. without exceeding the scope of the purpose of the present invention.

[0093] [Fluorinated ether compounds]

[0094] The fluorine-containing ether compound of the present embodiment is represented by the following formula (1).

[0095] R 1 -CH2-R 2 -(CH2-R 3 -CH2-R 2 ) z -CH2-R 4 (1)

[0096] (In formula (1), z is 1 or 2. R 2 is a perfluoropolyether chain. (z+1) R 2 Some or all of them may be the same, or they may be different. 1 It is a branched terminal group having 3 to 35 carbon atoms represented by the following formula (2). 4 is an organic group having 3 to 35 carbon atoms and having 1 to 3 polar groups, and R 1 Can be the same or different. 3 is a divalent linking group represented by the following formula (4). When z is 2, the two R 3 Can be the same or different.)

[0097]

[0098] (In formula (2), R 5 and R 6 It is an organic group that does not contain a secondary hydroxyl group or a tertiary hydroxyl group but contains one primary hydroxyl group, and they may be the same or different. x is an integer of 0 to 3.

[0099] (In formula (4), h is an integer from 1 to 3, and i is an integer from 1 to 3.)

[0100] In the fluorinated ether compound represented by formula (1), z is 1 or 2. Since z is less than 2, the fluorinated ether compound represented by formula (1) does not become too large. Therefore, it becomes a fluorinated ether compound that can move freely on the protective layer, is easy to wet and spread on the protective layer, and is easy to obtain a lubricating layer with uniform film thickness. In addition, since z is greater than 1, a divalent connecting group represented by formula (4) having a secondary hydroxyl group can be arranged between adjacent perfluoropolyether chains. Therefore, the central part of the chain structure of the fluorinated ether compound is in close contact with the protective layer. For example, compared with the case where z is 0 (the case where there is only one perfluoropolyether chain), it becomes a fluorinated ether compound that can form a lubricating layer with good adhesion to the protective layer.

[0101] (R 2 Perfluoropolyether chain shown)

[0102] In the fluorine-containing ether compound represented by formula (1), (z+1) R 2 Each independently represents a perfluoropolyether chain (hereinafter sometimes referred to as a "PFPE chain"). When a lubricant containing the fluorinated ether compound of the present embodiment is applied on 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.

[0103] In the fluorine-containing ether compound represented by formula (1), (z+1) R 2 Some or all of them may be the same, or they may be different. (z+1) R 2 It is preferred that all of them are the same. This is because the coating state of the protective layer with the fluorinated ether compound becomes uniform, and a lubricating layer with better adhesion is obtained. 2 Two or more R 2 The same means (z+1) R 2 Among them, the repeating units of the PFPE chain have the same structure as R 2 Contains 2 or more. In the same R2 The same repeating unit structure and different average polymerization degrees are also included. 2 .

[0104] As R 2 The PFPE chain shown in the above-mentioned example includes a PFPE chain formed of a polymer or copolymer of a perfluoroalkylene oxide, etc. Examples of the perfluoroalkylene oxide include perfluoromethylene oxide, perfluoroethylene oxide, perfluoro-n-propylene oxide, perfluoroisopropylene oxide, and perfluorobutylene oxide.

[0105] The (z+1) R in formula (1) 2 Preferably, each independently is a PFPE chain represented by the following formula (5) derived from, for example, a polymer or copolymer of a perfluoroalkylene oxide.

[0106] -(CF2) w1 -O-(CF2O) w2 -(CF2CF2O) w3 -(CF2CF2CF2O) w4 -(CF2CF2CF2CF2O) w5 -(CF2) w6 -(5)

[0107] (In formula (5), 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 (5).)

[0108] In formula (5), 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.

[0109] In formula (5), w1 and w6 are average values ​​representing the number of CF2, and each independently represents 1 to 3. w1 and w6 are determined by the structure of the repeating unit arranged at the end of the chain structure in the PFPE chain represented by formula (5).

[0110] In formula (5), (CF2O), (CF2CF2CF2O), (CF2CF2CF2O), (CF2CF2CF2CF2O) are repeating units. There is no particular restriction on the arrangement order of the repeating units in formula (5). In addition, there is no particular restriction on the number of types of repeating units in formula (5).

[0111] The (z+1) R in formula (1)2 Preferably, each independently is any one selected from the group consisting of PFPE chains represented by the following formula (5-1) to formula (5-4).

[0112] If (z+1) R 2 Each independently represents any one of the PFPE chains represented by formula (5-1) to (5-4), and thus a lubricating layer having good lubricity can be obtained. 2 When each independently represents any one of the PFPE chains represented by formula (5-1) to formula (5-4), 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, a fluorinated ether compound having a moderate hardness is obtained. Therefore, the fluorinated ether compound applied to the protective layer is not easily agglomerated on the protective layer, and a thinner lubricating layer can be formed with a sufficient coverage.

[0113] -CF2-(OCF2CF2) j -(OCF2) k -OCF2-(5-1)

[0114] (In formula (5-1), j and k represent average polymerization degrees, j represents 1 to 20, and k represents 0 to 20.)

[0115] -CF2CF2-(OCF2CF2CF2) l -OCF2CF2-(5-2)

[0116] (In formula (5-2), l represents the average degree of polymerization and is 1 to 15.)

[0117] -CF2CF2CF2-(OCF2CF2CF2CF2) m -OCF2CF2CF2-(5-3)

[0118] (In formula (5-3), m represents the average degree of polymerization and is 1 to 10.)

[0119] -(CF2) w7 -O-(CF2CF2CF2O) w8 -(CF2CF2O) w9 -(CF2) w10 -(5-4)

[0120] (In formula (5-4), 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 groups, and each independently represents 1 to 2.)

[0121] In formula (5-1), there is no particular restriction on the arrangement order of (OCF2CF2) and (OCF2) as repeating units. In formula (5-1), the number j of (OCF2CF2) and the number k of (OCF2) may be the same or different. The PFPE chain shown in formula (5-1) may be a polymer of (OCF2CF2). In addition, the PFPE chain shown in formula (5-1) may be any of a random copolymer, a block copolymer, and an alternating copolymer composed of (OCF2CF2) and (OCF2).

[0122] In formula (5-1) to formula (5-3), since j representing the average degree of polymerization is 1 to 20, k is 0 to 20, l is 1 to 15, and m is 1 to 10, it is a fluorine-containing ether compound that can obtain a lubricating layer with good lubricity. In addition, in formula (5-1) to formula (5-3), since j and k representing the average degree of polymerization are 20 or less, l is 15 or less, and m 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, j, k, l, and m representing the average degree of polymerization are preferably 1 to 10, more preferably 1.5 to 8, and further preferably 2 to 7.

[0123] In formula (5-4), there is no particular restriction on the arrangement order of (CF2CF2CF2O) and (CF2CF2O) as repeating units. In formula (5-4), the number w8 of (CF2CF2CF2O) and the number w9 of (CF2CF2O) may be the same or different. Formula (5-4) may include any of a random copolymer, a block copolymer, and an alternating copolymer formed by monomer units (CF2CF2CF2O) and (CF2CF2O).

[0124] In formula (5-4), w8 and w9, which represent the average degree of polymerization, are each independently 1 to 20, preferably 1 to 15, and more preferably 1 to 10.

[0125] w7 and w10 in formula (5-4) are average values ​​representing the number of CF2, and each independently represents 1 to 2. w7 and w10 are determined by the structure of the repeating unit arranged at the end of the chain structure in the perfluoropolyether chain represented by formula (5-4).

[0126] (R 3 The divalent linking group shown

[0127] In the fluorine-containing ether compound represented by formula (1), R 3 is a divalent linking group represented by formula (4). 3 They are respectively configured in (z+1) R2 Between the PFPE chains shown. Thus, R 3 The fluorine-containing ether compound is brought into close contact with the protective layer, and a thin lubricating layer is formed with a sufficient coverage.

[0128] In addition, R 3 The divalent linking group shown has only one secondary hydroxyl group and is located between adjacent PFPE chains. 3 The secondary hydroxyl groups in the lubricating layer are less likely to hinder the bonding with the active points on the protective layer, and the lubricating layer is bonded with the active points on the protective layer to improve the adhesion with the protective layer. As a result, the lubricating layer containing the fluorinated ether compound represented by formula (1) is inhibited from being arranged in R 3 The PFPE chains at both ends of the film are too far away from the protective layer, and the surface irregularities are reduced, resulting in a material with excellent smoothness.

[0129] In formula (4), h and i are preferably integers of 1 to 3, and at least one of h and i is 1. It is preferred that at least one of h and i is 1 because the production of the fluorinated ether compound becomes easy. In order to maintain the flexibility of the entire linking group, it is more preferred that h is 1 and i is 1.

[0130] When z in formula (1) is 2, the two R 3 They can be the same or different. 3 If the fluorinated ether compound is the same as the fluorinated ether compound, the coating state of the protective layer becomes more uniform, and a lubricating layer with better adhesion can be formed. 3 The same refers to 2 R 3 The atoms involved are relative to the central R 2 are symmetrically configured.

[0131] (R 1 terminal groups shown)

[0132] In formula (1), R 1 The terminal group represented by is a branched terminal group having 3 to 35 carbon atoms represented by the following formula (2). Among the branched terminal groups represented by formula (2), two organic groups (R 5 and R 6 ) is bound to a trisubstituted carbon atom serving as a branch point.

[0133]

[0134] (In formula (2), R 5 and R 6 It is an organic group that does not contain a secondary hydroxyl group or a tertiary hydroxyl group but contains one primary hydroxyl group, and they may be the same or different. x is an integer of 0 to 3.

[0135] The number of carbon atoms in the branched terminal group represented by formula (2) is 3 to 35, preferably 3 to 20, and more preferably 3 to 12. The number of carbon atoms in the branched terminal group may be 3 to 5, 5 to 10, or 10 to 15.

[0136] Since the number of carbon atoms in the branched terminal group shown in formula (2) is less than 35, the distance between the two primary hydroxyl groups contained in the branched terminal group will not be too far. Therefore, the two primary hydroxyl groups contained in the branched terminal group shown in formula (2) can easily form an orientation in which both are easily adsorbed on the protective layer and are easy to combine with the active points on the protective layer. In addition, since the number of carbon atoms in the branched terminal group shown in formula (2) is 3 to 35, the ratio of the number of carbon atoms to the number of hydroxyl groups becomes appropriate, and the molecular polarity becomes a fluorine-containing ether compound with appropriate fluorine atom content. In addition, if the number of carbon atoms in the branched terminal group shown in formula (2) is 3 to 12, the ratio of fluorine atoms in the fluorine-containing ether compound molecule can be suppressed from decreasing and the surface free energy of the molecule as a whole can be increased.

[0137] In formula (2), x represents an integer of 0 to 3. Preferably, x is 1 to 3. In this case, R 2 The interatomic distance between the perfluoropolyether chain shown in the formula (2) and the trisubstituted carbon atom contained in the formula (2) becomes more appropriate. 2 The interatomic distance between the perfluoropolyether chain shown and the two primary hydroxyl groups included in formula (2) is also more suitable. Therefore, the two primary hydroxyl groups included in formula (2) are less susceptible to the large volume caused by the adjacent perfluoropolyether chains and are easily adsorbed to the protective layer. As a result, a lubricating layer with better adhesion to the protective layer and better wear resistance is obtained.

[0138] In formula (2), R 5 and R 6 Each independently represents an organic group that does not contain a secondary hydroxyl group or a tertiary hydroxyl group but contains one primary hydroxyl group and is bonded to a trisubstituted carbon atom. 5 and R 6 The number of carbon atoms constituting each of R is 1 or more. 5 and R 6 The organic groups shown in the formula (a) may be linear or branched, preferably linear. 5 (or R 6 ) is a straight chain organic group, then 5 (or R 6 ) has a branched organic group, R 5 (or R 6 ) can move freely. 5 (or R 6) can more easily form a bond with the active sites on the protective layer.

[0139] Preferably, R in formula (2) 5 and R 6 The two primary hydroxyl groups contained are at least 5 atoms away from each other. 5 and R 6 The oxygen atom of one of the two primary hydroxyl groups is preferably connected to the oxygen atom of the other primary hydroxyl group via a linking group in which 5 or more atoms of trisubstituted carbon atoms are connected. In this case, the two primary hydroxyl groups in formula (2) are sufficiently far from each other, and the interaction between the primary hydroxyl groups is not likely to be dominant, which can more effectively inhibit the adjacent primary hydroxyl groups from hindering the bonding with the protective layer. Therefore, in R 5 and R 6 When the two primary hydroxyl groups are separated by 5 atoms or more, R 5 and R 6 The two contained primary hydroxyl groups can more easily form bonds with active sites on the protective layer, and can form a lubricating layer with better smoothness.

[0140] R in formula (2) 5 and / or R 6 The organic group preferably contains one or more ether bonds (-O-). In this case, since the branched terminal group represented by formula (2) has moderate flexibility, the lubricating layer containing the fluorinated ether compound represented by formula (1) has better adhesion to the protective layer.

[0141] In formula (2), R 5 (or R 6 ) shown in the case where the organic group has multiple ether bonds, adjacent ether bonds are preferably combined via a connecting group to which more than 2 carbon atoms are connected. In this case, the distance between adjacent ether bonds becomes appropriate, becoming a fluorine-containing ether compound that is not easy to agglomerate.

[0142] Formula (2) is preferably any branched terminal group of the following formula (2-1) or formula (2-2). In the case where formula (2) is any branched terminal group of formula (2-1) or formula (2-2), the carbon atoms bound to the two primary hydroxyls contained in formula (2-1) or formula (2-2) are bound to each other via any of the connecting groups selected from the connecting group consisting of methine, the connecting group containing methine and methylene, the connecting group containing methine, methylene and ether bond. Therefore, for the branched terminal group possessed by formula (2-1) or formula (2-2), the distance between the two primary hydroxyls possessed by the branched terminal group is appropriate, and the two primary hydroxyls do not hinder the combination with the active points on the protective layer. Therefore, the two primary hydroxyls possessed by formula (2-1) or formula (2-2) can interact with the protective layer independently.

[0143] Moreover, if formula (2) is any branched terminal group of formula (2-1) or formula (2-2), the number of carbon atoms in the branched terminal group will not be too much, and the molecular weight of formula (2-1) or formula (2-2) will not become too large. Therefore, the ratio of fluorine atoms in the fluorine-containing ether compound molecule is not easy to decrease, and the surface free energy of the entire molecule can be suppressed from becoming larger.

[0144]

[0145] (In formula (2-1), a is an integer of 1 to 3, and b is an integer of 1 to 4. 1 is a hydrogen atom or a group represented by formula (3). 2 is a group represented by formula (3). 1 With X 2 Can be the same or different.)

[0146] (In formula (2-2), c is an integer of 0 to 3, and d and e are each independently an integer of 1 to 5. 3 and X 4 Each independently represents a hydrogen atom or a group represented by formula (3). 3 With X 4 Can be the same or different.)

[0147] (In formula (3), f is an integer of 2 to 5, and g is 1 or 2.)

[0148] a in formula (2-1) represents an integer of 1 to 3. Since a in formula (2-1) is an integer of 1 to 3, R 2 The perfluoropolyether chain shown in the formula (2-1) and the interatomic distance of the trisubstituted carbon atom contained in the formula (2-1) are appropriate. Therefore, the two primary hydroxyl groups contained in the formula (2-1) are less susceptible to the large volume caused by the adjacent perfluoropolyether chains and are more easily adsorbed on the protective layer. As a result, a lubricating layer with better wear resistance can be formed. In order to easily ensure the ratio of fluorine atoms in the fluorinated ether compound molecule, a is preferably an integer of 1 or 2, and most preferably 1.

[0149] b in formula (2-1) represents an integer of 1 to 4. 1 In the case of formula (3), in order to easily ensure the ratio of fluorine atoms in the fluorine-containing ether compound molecule, b is preferably an integer of 1 or 2. 1 is a hydrogen atom, and X 2 When f in (= in formula (3)) is 2 or 3, b in formula (2-1) is preferably 2 to 4, more preferably 3 or 4. 1 is a hydrogen atom, and X 2In the case where f in (= in formula (3)) is 2 or 3, if b in formula (2-1) is 2 or more, the interatomic distance between the two primary hydroxyl groups included in formula (2-1) becomes more appropriate. Therefore, it is possible to effectively suppress the two primary hydroxyl groups included in formula (2-1) from hindering each other from binding to the active points on the protective layer. As a result, the two primary hydroxyl groups included in formula (2-1) are more easily adsorbed to the protective layer, and a lubricating layer with better wear resistance and smoothness can be formed.

[0150] X in formula (2-1) 1 is a hydrogen atom or a group represented by formula (3). 2 is a group represented by formula (3). 1 With X 2 Can be the same or different. 1 and X 2 When all of them are groups represented by formula (3) and are the same, the production of the fluorinated ether compound may be facilitated, which is preferred. 1 With X 2 In different cases, in order to easily ensure the ratio of fluorine atoms in the fluorine-containing ether compound molecule, X 1 Preferred is a hydrogen atom.

[0151] In formula (2-2), c represents an integer of 0 to 3. In order to easily ensure the ratio of fluorine atoms in the fluorine-containing ether compound molecule, c is preferably an integer of 0 to 2. 2 The interatomic distance between the perfluoropolyether chain shown and the trisubstituted carbon atom contained in formula (2-2) becomes more appropriate, and R 2 The interatomic distance between the perfluoropolyether chain shown and the two primary hydroxyl groups contained in formula (2-2) is likely to become more appropriate, and c is more preferably 1 or 2. In particular, in X 3 and X 4 In the case of a hydrogen atom, for R 2 The interatomic distance between the perfluoropolyether chain shown and the two primary hydroxyl groups contained in formula (2-2) becomes more appropriate, and a lubricating layer with more excellent wear resistance can be formed. More preferably, c is 1 or 2.

[0152] In formula (2-2), d and e each independently represent an integer of 1 to 5. In order to easily ensure the ratio of fluorine atoms in the fluorine-containing ether compound molecule, d and e are preferably each independently an integer of 1 to 3, and more preferably 1 or 2. d and e may be the same or different. In order to facilitate the manufacture of the fluorine-containing ether compound, d and e are preferably the same. In addition, in order to make the interatomic distance between the two primary hydroxyl groups contained in formula (2-2) appropriate, the total of d and e is preferably 4 or more. In addition, in order for R 2The interatomic distance between the perfluoropolyether chain shown and the primary hydroxyl group contained in formula (2-2) tends to be more appropriate, and the sum of c and d and the sum of c, e and d are each preferably 3 or more.

[0153] X in formula (2-2) 3 and X 4 is a hydrogen atom or a group represented by formula (3). 3 With X 4 Can be the same or different. 3 With X 4 In the same case, since the manufacture of fluorine-containing ether compounds is easy, it is preferred. In order to easily ensure the ratio of fluorine atoms in the fluorine-containing ether compound molecules, it is preferred that X 3 and / or X 4 is a hydrogen atom, more preferably X 3 and X 4 Both are hydrogen atoms.

[0154] f in formula (3) represents an integer of 2 to 5. f is preferably an integer of 2 to 4, and more preferably 2 or 3. f in formula (3) is determined based on the values ​​of a and b in formula (2-1), and X 1 The type of, the values ​​of c, d, e in formula (2-2), etc. can be appropriately determined.

[0155] In formula (2-1), X 1 is a hydrogen atom and X 2 In the case of formula (3), f in formula (3) is preferably 2 or 3. The reason is that the interatomic distance between two primary hydroxyl groups included in formula (2-1) tends to become more appropriate.

[0156] In formula (2-2), X 3 and / or X 4 In the case of the formula (3), f in the formula (3) is preferably 2 or 3 in order to easily secure the ratio of fluorine atoms in the fluorine-containing ether compound molecule.

[0157] g in formula (3) represents 1 or 2. When g is 2, each [-(CH2) f In the formula (3), f may be the same or different. In order to easily ensure the ratio of fluorine atoms in the fluorine-containing ether compound molecule, g in the formula (3) is preferably 1.

[0158] (R 4 terminal groups shown)

[0159] In the fluorine-containing ether compound represented by formula (1), R 4 The terminal group shown is an organic group having 3 to 35 carbon atoms and having 1 to 3 polar groups. 4The terminal group shown is preferably an organic group having 3 to 20 carbon atoms, and more preferably an organic group having 3 to 12 carbon atoms. 4 When the number of carbon atoms constituting the terminal group is 3 to 35, the ratio of the number of carbon atoms to the number of polar groups becomes appropriate, and the fluorine-containing ether compound having appropriate molecular polarity becomes available.

[0160] R 4 The terminal group shown in is preferably an oxygen atom bonded to the end of the adjacent methylene group. In this case, R 4 The fluorinated ether compound is bonded to the adjacent methylene group via an ether bond to form a fluorinated ether compound having moderate hardness. Therefore, the fluorinated ether compound coated on the protective layer is not easy to aggregate on the protective layer, and a lubricating layer having better coating properties and smoothness can be formed even if the thickness is reduced.

[0161] As R 4 The polar groups possessed by the terminal groups shown in the figure include, for example, hydroxyl (-OH), amino (-NR 7 R 8 ; R 7 and R 8 Each is independently a hydrogen atom or an organic group. ), carboxyl (-COOH), formyl (-(C=O)H), carbonyl (-(C=O)R 9 ; R 9 is an organic group. ), sulfonyl (-SO3H), cyano (-CN), a group having an amide bond (-NR 10 COR 11 or-CONR 12 R 13 ; R 10 , R 11 , R 12 and R 13 Each independently represents a hydrogen atom or an organic group. ) etc. In addition, as shown in the above formula, the "group having an amide bond" includes both a group that is bonded to the carbon atom constituting the amide bond (e.g., a formamide group (-C(=O)NH2)) and a group that is bonded to the nitrogen atom constituting the amide bond (e.g., an acetamide group (-NHC(=O)CH3)). In the group having an amide bond, the above R 10 With R 11 can be combined with each other to form a ring, the above R 12 With R 13 The above R in the group having an amide bond may be bonded to each other to form a ring. 10 , R 11 , R 12 and R 13 Preferably, they are each independently selected from a hydrogen atom, a methyl group, an ethyl group, a propyl group, and a butyl group.

[0162] In R 4 When the terminal group shown in the formula (I) has a polar group containing carbon atoms (e.g., a carboxyl group, a formyl group, a carbonyl group, a cyano group, or a group having an amide bond), the carbon atom contained in the polar group is contained in R 4 The number of carbon atoms constituting the terminal group shown.

[0163] In order to form a fluorinated ether compound capable of forming a lubricating layer having better adhesion to the protective layer, R 4 The number of polar groups possessed by the terminal group shown is 1 to 3, preferably 2 or 3. If the number of polar groups is 3 or less, in a magnetic recording medium having a lubricating layer containing a fluorinated ether compound, aggregation of the fluorinated ether compound due to excessive polar groups contained in the fluorinated ether compound can be prevented, thereby preventing the smoothness from being reduced.

[0164] In R 4 When two or more polar groups are included, the two or more polar groups are preferably bonded to different carbon atoms, and one or more carbon atoms are included between the carbon atoms to which the adjacent polar groups are bonded. In this case, the adjacent polar groups are bonded to form an appropriate interatomic distance compared to the case where the carbon atoms bonded to the adjacent polar groups are directly bonded to each other. Therefore, R 4 The multiple polar groups possessed by the protective layer are oriented so as to be closely attached to the protective layer. 4 The multiple polar groups possessed are less likely to aggregate and can easily form bonds with active sites on the protective layer.

[0165] R 4 The terminal group shown may be an organic group having 1 to 3 polar groups and further having a carbon-carbon unsaturated bond site. 4 When the terminal group shown has a carbon-carbon unsaturated bond site, the terminal group is preferably an organic group having at least one selected from an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, and an alkynyl group.

[0166] Examples of the aromatic hydrocarbon group include phenyl, methoxyphenyl, fluorophenyl, naphthyl, methoxynaphthyl, etc. The aromatic hydrocarbon group includes a group in which a substituent such as a methoxy group or a fluoro group is bonded to an aromatic hydrocarbon as described above.

[0167] Examples of the unsaturated heterocyclic group include pyrrolyl, pyrazolyl, methylpyrazolyl, imidazolyl, furyl, furanyl, Azolyl, iso oxazolyl, thienyl, thiazolyl, isothiazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, indolinyl, benzofuranyl, benzothiophenyl, benzimidazolyl, benzo Azolyl, benzothiazolyl, benzopyrazolyl, benzisophthalic acid Examples of the unsaturated heterocyclic group include oxazolyl, benzisothiazolyl, quinolyl, isoquinolyl, quinazolinyl, quinoxalinyl, phthalazinyl, cinnolinyl, etc. The unsaturated heterocyclic group includes groups in which a substituent such as a methyl group is bonded to the unsaturated heterocyclic ring as described above.

[0168] Examples of the alkenyl group include vinyl, allyl, butenyl, pentenyl, and hexenyl.

[0169] Examples of the alkynyl group include 1-propynyl, propargyl, butynyl, pentynyl, and hexynyl.

[0170] In R 4 When the terminal group has a carbon-carbon unsaturated bond site, the lubricating layer containing a fluorine-containing ether compound is preferred because it has excellent adhesion to the protective layer and can be made thin. The reason is described below.

[0171] Among the active sites that exist in large numbers on the protective layer, there are sites that are locally charged and sites where the charge distribution is spread. 1 and R 3 The hydroxyl groups (and R 4 In the case of having a hydroxyl group), and R 4 The carbon-carbon unsaturated bond sites included in the terminal groups shown are adsorbed to different sites on the protective layer.

[0172] Specifically, R in formula (1) 1 and R 3 The hydroxyl groups (and R 4 The hydroxyl group in the case of having a hydroxyl group) exhibits adsorption ability by interacting with the locally charged site on the protective layer through hydrogen bonds. 4 Since the carbon-carbon unsaturated bond site included in the terminal group has a non-localized charge, it exhibits adsorption capability by interacting with the site where the charge distribution on the protective layer is expanded.

[0173] Therefore, R in formula (1) 1 and R 3 The hydroxyl groups (and R 4 In the case of having a hydroxyl group), and R 4 The carbon-carbon unsaturated bond sites contained in the terminal groups shown can interact independently with the active sites on the protective layer. 4 The fluorinated ether compound having a carbon-carbon unsaturated bond site at the terminal group has a more excellent adhesion between the lubricating layer and the protective layer, good smoothness and high wear resistance.

[0174] R 4 The terminal group shown may contain 2 primary hydroxyl groups. In this case, R4 Preferably, it contains no polar groups other than the two primary hydroxyl groups. 4 In the case where no polar groups are included except for two primary hydroxyl groups with high mobility and adsorption, it is possible to prevent the generation of free polar groups due to excessive polar groups that can participate in adsorption to the protective layer and thus fail to adsorb to the protective layer. Therefore, it is possible to prevent the polar groups between molecules and / or within molecules from aggregating with each other.

[0175] R 4 With R 1 Similarly, it may be a branched terminal group represented by the above formula (2). In this case, R 4 The two primary hydroxyl groups contained in formula (2) and R 1 The two primary hydroxyl groups contained in formula (2) are also easily involved in the bonding with the active points present on the protective layer. 4 In the case of a branched terminal group represented by formula (2), 1 Similarly, it has moderate flexibility due to bonding to adjacent methylene groups via ether bonds, and has sufficient fluidity and flexibility due to the high mobility of two primary hydroxyl groups contained in the branched terminal group represented by formula (2). Therefore, it is estimated that the lubricating layer containing the fluorinated ether compound represented by formula (1) has good adhesion to the protective layer, good smoothness, and excellent wear resistance.

[0176] In R 4 In the case of a branched terminal group represented by formula (2), R 4 Preferably, it is any branched terminal group of the above formula (2-1) or formula (2-2). In this case, the preferred values ​​of a and b in formula (2-1), c to e in formula (2-2), and f and g in formula (3) are the same as R 1 The same applies to any branched terminal group of formula (2-1) or formula (2-2).

[0177] In formula (1), in R 4 In the case of a branched terminal group represented by formula (2), it is more preferred that R 1 and R 4 Both are branched terminal groups of any one of the above formula (2-1) or formula (2-2).

[0178] In formula (1), in R 4 In the case of a branched terminal group represented by formula (2), R 1 With R 4 Preferably the same, more preferably R 1 and R 4 Both are the above formula (2-1) or formula (2-2). If R 1 With R 4If the coating state of the protective layer with the fluorinated ether compound is the same, the coating state of the protective layer with the fluorinated ether compound becomes more uniform, and a lubricating layer with better adhesion can be formed.

[0179] In the fluorine-containing ether compound represented by formula (1), z is preferably 1, and R 1 With R 4 Same, 2 R 2 The reason is that it is a fluorine-containing ether compound that is easy to synthesize. In addition, the reason is that the fluorine-containing ether compound with a symmetrical structure is easier to wet and spread on the protective layer, and can form a lubricating layer with good coating properties.

[0180] In the fluorine-containing ether compound represented by formula (1), z is preferably 2, and R 1 With R 4 Same, 3 Rs 2 The reason is that it is a fluorine-containing ether compound that is easy to synthesize. Further, when z is 2, preferably 2 R 3 The reason is that it is easier to synthesize the fluorine-containing ether compound. In addition, the reason is that the fluorine-containing ether compound with a symmetrical structure is easier to wet and spread on the protective layer, and can form a lubricating layer with good coating properties.

[0181] In R 4 When it is not a terminal group represented by formula (2), R 4 The terminal group shown is preferably a terminal group containing 2 or 3 polar groups, at least one of which is a secondary hydroxyl group. 4 When it is not a terminal group represented by formula (2), R 4 Specifically, the terminal group represented by is preferably any one of the terminal groups represented by the following formula (6-1) to formula (6-3).

[0182]

[0183] (In formula (6-1), y1 is 1 or 2, and y2 is an integer from 0 to 3. 5 is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, an alkynyl group, or a polar group. 5 is a polar group. 5 When X is an aromatic hydrocarbon group or an unsaturated heterocyclic group, 5 The atoms in the ring structure are bound to X 5 Adjacent methylene groups. 5 When it is an alkenyl group or an alkynyl group, X 5 The unsaturated carbon atom in the bond is bonded to X 5 adjacent methylene groups. )

[0184] (In formula (6-2), y3 is an integer from 1 to 3, y4 is 0 or 1, and y5 is an integer from 0 to 3.5 is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, an alkynyl group, or a polar group. 5 is a polar group. 5 When X is an aromatic hydrocarbon group or an unsaturated heterocyclic group, 5 The atoms in the ring structure are bound to X 5 Adjacent methylene groups. 5 When it is an alkenyl group or an alkynyl group, X 5 The unsaturated carbon atom in the bond is bonded to X 5 adjacent methylene groups. )

[0185] (In formula (6-3), y6 is 0 or 1, y7 is an integer from 1 to 3, and y8 is an integer from 1 to 3. 5 is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, an alkynyl group, or a polar group. 5 is a polar group. 5 When X is an aromatic hydrocarbon group or an unsaturated heterocyclic group, 5 The atoms in the ring structure are bound to X 5 Adjacent methylene groups. 5 When it is an alkenyl group or an alkynyl group, X 5 The unsaturated carbon atom in the bond is bonded to X 5 adjacent methylene groups. )

[0186] In formula (6-1) to formula (6-3), in X 5 When X is an aromatic hydrocarbon group, 5 The atoms in the ring structure are bound to X 5 Adjacent methylene groups. 5 In the case of an aromatic hydrocarbon group, X 5 , the aromatic hydrocarbon groups exemplified above can be used.

[0187] In formula (6-1) to formula (6-3), in X 5 When it is an unsaturated heterocyclic group, X 5 The atoms in the ring structure are bound to X 5 Adjacent methylene groups. 5 In the case of an unsaturated heterocyclic group, X 5 , the unsaturated heterocyclic groups exemplified above can be used.

[0188] In formula (6-1) to formula (6-3), in X 5 In the case of alkenyl, X 5 The unsaturated carbon atom in the bond is bonded to X 5 Adjacent methylene groups. 5In the case of alkenyl, X 5 , for example, -CH=CH2, -CH=CHR 14 (R 14 Is an organic group. ), -CR 15 =CHR 16 (R 15 , R 16 Is an organic group. ), -CR 17 =CR 18 R 19 (R 17 , R 18 , R 19 is an organic group. ) etc. 14 ~R 19 The organic groups shown are preferably hydrocarbon groups having 1 to 3 carbon atoms. In formulas (6-1) to (6-3), X 5 In the case of alkenyl, X 5 -CH=CH2 is preferred. -CH=CH2 has a suitable large volume. Therefore, 5 The lubricating layer of the fluorinated ether compound having a terminal group of -CH=CH2 tends to be in a state where the bulkiness of the fluorinated ether compound on the protective layer is low and the smoothness is good.

[0189] In formula (6-1) to formula (6-3), in X 5 In the case of an alkynyl group, X 5 The unsaturated carbon atom in the bond is bonded to X 5 Adjacent methylene groups. 5 In the case of an alkynyl group, as X 5 , for example, -C≡CH, -C≡CR 20 (R 20 is an organic group. ) etc. 20 The organic group represented by is preferably a hydrocarbon group having 1 to 3 carbon atoms. In formulas (6-1) to (6-3), X 5 In the case of an alkynyl group, in order to form a terminal group with a suitably large volume, X is preferably 5 -C≡CH.

[0190] In formula (6-1) to formula (6-3), in X 5 In the case of a polar group, X 5 , the polar groups exemplified above can be used. Among these polar groups, X 5 Preferably, it is a hydroxyl group, a group having an amide bond, or a cyano group. 5 If the hydroxyl group, the group having an amide bond, or the cyano group is used, when a lubricating layer is formed on the protective layer using a lubricant containing the hydroxyl group, the group having an amide bond, or the cyano group, a more suitable interaction occurs between the lubricating layer and the protective layer.

[0191] In formula (6-1) to formula (6-3), X 5 In the case of a polar group, a lubricating layer containing a fluorine-containing ether compound is preferred because it has better adhesion with the protective layer and can be made thinner. The reason is described below.

[0192] In formula (6-1) to formula (6-3), the secondary hydroxyl group in formula (6-1) to formula (6-3) and X 5 The bond is via a divalent organic group which may contain an ether bond. 5 is a polar group, and the secondary hydroxyl group in formula (6-1) to formula (6-3) and X 5 As a result, the distance between the secondary hydroxyl group and X in formula (6-1) to formula (6-3) is appropriate. 5 The polar groups shown are not easily hindered from binding to the active sites on the protective layer by other polar groups. 5 The polar groups shown do not easily aggregate.

[0193] Therefore, the secondary hydroxyl group and X in formula (6-1) to formula (6-3) 5 The polar groups shown can be adsorbed independently on the active sites on the protective layer. As a result, the X 5 The lubricating layer of the fluorine-containing ether compound having a terminal group as a polar group has excellent adhesion to the protective layer, good smoothness, and excellent wear resistance even if the thickness is thin.

[0194] In the above, X in formula (6-1) to formula (6-3) 5 Any of a hydroxyl group, a group having an amide bond, a cyano group, and -CH=CH2 is preferred because it is a fluorine-containing ether compound that can form a lubricating layer having a higher coverage rate and excellent smoothness and wear resistance.

[0195] In the terminal group represented by formula (6-1), y1 is 1 or 2, and y2 is an integer from 0 to 3. When y1 is 1, X 5 is a polar group, and formula (6-1) has two polar groups. In this case, since formula (6-1) has two polar groups, a lubricating layer with good adhesion to the protective layer can be formed. When y1 is 2, X 5 It may be any one of an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, an alkynyl group, and a polar group. 5 When X is any one of an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, and an alkynyl group, Formula (6-1) also has two polar groups. Therefore, a lubricating layer having good adhesion to the protective layer can be formed.5 is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group or an alkynyl group, so that the adhesion of the two hydroxyl groups contained in formula (6-1) to the protective layer is not impaired. 5 The carbon-carbon unsaturated bond sites interact with the π-π of the protective layer, thereby forming a lubricating layer with excellent smoothness and wear resistance. 5 When it is a polar group, the formula (6-1) has three polar groups. Therefore, a lubricating layer having better adhesion to the protective layer can be formed.

[0196] In the terminal group represented by formula (6-1), y2 is an integer of 0 to 3. For the terminal group represented by formula (6-1), even if X in formula (6-1) 5 As a polar group, also because X 5 The distance to the secondary hydroxyl group in formula (6-1) is not too close, so the polar group in formula (6-1) is not easy to aggregate. 5 When X is a polar group, 5 The distance from the secondary hydroxyl group in formula (6-1) becomes more appropriate, so y2 is preferably 1 or more. For the terminal group represented by formula (6-1), since y2 is 3 or less, X in formula (6-1) 5 The mobility of will not become too high, and each polar group possessed by the terminal group can be sufficiently adhered to the protective layer. y2 is more preferably 2 or less.

[0197] In the terminal group represented by formula (6-2), y3 is an integer of 1 to 3. When y4 is 0, X 5 Since y3 is an integer greater than 1, when y4 is 0, X 5 The distance from the secondary hydroxyl group in formula (6-2) becomes appropriate, even if X 5 It is a polar group, and the polar group in formula (6-2) is not easy to agglomerate. In addition, since y3 is an integer greater than 1, when y4 is 1, the distance between the secondary hydroxyl groups in formula (6-2) will not become too close, and the secondary hydroxyl groups in formula (6-2) are not easy to agglomerate. For the terminal group shown in formula (6-2), since y3 is less than 3, the mobility of the terminal group shown in formula (6-2) will not become too high, and each polar group possessed by the terminal group can be fully fitted with the protective layer. y3 is preferably less than 2.

[0198] In the terminal group represented by formula (6-2), y4 is 0 or 1. When y4 is 0, X 5 is a polar group, and formula (6-2) has two polar groups. In this case, since formula (6-2) has two polar groups, a lubricating layer with good adhesion to the protective layer can be formed. 5It may be any one of an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, an alkynyl group, and a polar group. 5 When X is any one of an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group or an alkynyl group, the formula (6-2) has two polar groups. Therefore, a lubricating layer having good adhesion to the protective layer can be formed. 5 is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group or an alkynyl group, so that the adhesion of the two hydroxyl groups contained in formula (6-2) to the protective layer is not impaired. 5 The carbon-carbon unsaturated bond site interacts with the π-π of the protective layer, thereby forming a lubricating layer with excellent smoothness and wear resistance. 5 When it is a polar group, the formula (6-2) has three polar groups. Therefore, a lubricating layer having excellent adhesion to the protective layer can be formed.

[0199] In the terminal group represented by formula (6-2), y5 is an integer of 0 to 3. For the terminal group represented by formula (6-2), even if X in formula (6-2) 5 is a polar group, X 5 The distance to the secondary hydroxyl group in formula (6-2) is not too close, so the polar group in formula (6-2) is not easy to aggregate. 5 In the case of a polar group, for X 5 The distance from the secondary hydroxyl group in formula (6-2) becomes more appropriate, and y5 is preferably greater than 1. In addition, when y4 is 0, even if y5 is 0, y3 methylene groups are present to form a polar group X. 5 The distance from the secondary hydroxyl group in formula (6-2) becomes appropriate. When y4 is 0, if y5 is 1 or more, the polar group X is formed by y3+y5 methylene groups. 5 The distance from the secondary hydroxyl group in formula (6-2) is more appropriate and therefore preferred. For the terminal group represented by formula (6-2), since y5 is 3 or less, X in formula (6-2) 5 The mobility of the terminal group will not become too high, and each polar group possessed by the terminal group can be sufficiently adhered to the protective layer. y5 is preferably 2 or less.

[0200] In the terminal group represented by formula (6-3), y6 is 0 or 1. When y6 is 0, X 5 is a polar group, and formula (6-3) has two polar groups. In this case, since formula (6-3) has two polar groups, a lubricating layer with good adhesion to the protective layer can be formed. 5 It may be any of an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, an alkynyl group, and a polar group. 5When X is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group or an alkynyl group, the formula (6-3) also has two polar groups. Therefore, a lubricating layer having good adhesion to the protective layer can be formed. 5 is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group or an alkynyl group, so that the adhesion of the two hydroxyl groups contained in formula (6-3) to the protective layer is not impaired. 5 The carbon-carbon unsaturated bond site interacts with the π-π of the protective layer, thereby forming a lubricating layer with excellent smoothness and wear resistance. 5 When it is a polar group, the formula (6-3) has three polar groups. Therefore, a lubricating layer having excellent adhesion to the protective layer can be formed.

[0201] In the terminal group represented by formula (6-3), y7 is an integer of 1 to 3. Since y7 is greater than 1, when y6 is 1, the distance between the secondary hydroxyl groups in formula (6-3) will not become too close. Therefore, the secondary hydroxyl groups in formula (6-3) are not easy to agglomerate. For the terminal group represented by formula (6-3), since y7 is less than 3, the mobility of the terminal group represented by formula (6-3) will not become too high, and each polar group possessed by the terminal group can be fully adhered to the protective layer. y7 is preferably less than 2.

[0202] In the terminal group represented by formula (6-3), y8 is an integer of 1 to 3. Since y8 is 1 or more, even if X in formula (6-3) 5 is a polar group, X 5 The distance to the secondary hydroxyl group in formula (6-3) will not become too close. Therefore, the polar group in formula (6-3) is not easy to aggregate. 5 In the case of a polar group, for X 5 The distance from the secondary hydroxyl group in formula (6-3) becomes more appropriate, and y8 is preferably 2 or more. For the terminal group represented by formula (6-3), since y8 is 3 or less, X in formula (6-3) 5 The mobility of the terminal group does not become too high, and each polar group possessed by the terminal group can be sufficiently adhered to the protective layer.

[0203] In the fluorine-containing ether compound represented by formula (1), R 1 and R 4 The type of the terminal group shown above can be appropriately selected depending on the performance required of the lubricant containing the fluorine-containing ether compound, etc.

[0204] Specifically, the fluorine-containing ether compound represented by (1) is preferably any one of the compounds represented by the following formulas (1A) to (1O) and (2A) to (2O). When the compound represented by formula (1) is any one of the compounds represented by the following formulas (1A) to (1O) and (2A) to (2O), the raw material is easy to obtain, and a lubricating layer having excellent adhesion, smoothness and wear resistance can be formed even with a thin thickness.

[0205] The compounds represented by the following formulas (1A) to (1O) and (2A) to (2O) are all R in formula (1): 1 With R 4 The same as the group represented by formula (2-1) or formula (2-2), and as R 3 In formula (4), h and i are 1.

[0206] The compounds represented by the following formulas (1A) to (1O) and (2A) to (2O) are all R in formula (1): 2 The (z+1) PFPE chains shown are all identical.

[0207] In the compounds represented by the following formulae (1A) to (1O) and (2A) to (2O), Rf1 and Rf2 representing the PFPE chain each have the following structure. That is, in the compounds represented by the following formulae (1A) to (1F), (1J), (1K), (1N), (2A) to (2F), (2J), (2K), and (2N), Rf2 is a PFPE chain represented by the following formula (7-2). In the compounds represented by the following formulae (1G) to (1I), (1L), (1M), (1O), (2G) to (2I), (2L), (2M), and (2O), Rf1 is a PFPE chain represented by the following formula (7-1). In addition, p and q in Rf1 and r in Rf2 representing the PFPE chain in Formulas (1A) to (10) and (2A) to (20) are values ​​representing the average degree of polymerization and are not necessarily integers.

[0208]

[0209] (In the two Rf2 in formula (1A), r represents the average degree of polymerization and is 1 to 15. The r in the two Rf2 may be the same or different.)

[0210] (In the two Rf2 in formula (1B), r represents the average degree of polymerization and is 1 to 15. The r in the two Rf2 may be the same or different.)

[0211] (In the two Rf2 in formula (1C), r represents the average degree of polymerization and is 1 to 15. The r in the two Rf2 may be the same or different.)

[0212] (In the two Rf2 in formula (1D), r represents the average degree of polymerization and is 1 to 15. The r in the two Rf2 may be the same or different.)

[0213] (In the two Rf2 in formula (1E), r represents the average degree of polymerization and is 1 to 15. The r in the two Rf2 may be the same or different.)

[0214]

[0215] (In the two Rf2 in formula (1F), r represents the average degree of polymerization and is 1 to 15. The r in the two Rf2 may be the same or different.)

[0216] (In the two Rf1 in formula (1G), p and q represent the average degree of polymerization, p represents 1 to 20, and q represents 0 to 20. p and q in the two Rf1 may be the same or different.)

[0217] (In the two Rf1 in formula (1H), p and q represent the average degree of polymerization, p represents 1 to 20, and q represents 0 to 20. p and q in the two Rf1 may be the same or different.)

[0218] (In the two Rf1 in formula (1I), p and q represent the average degree of polymerization, p represents 1 to 20, and q represents 0 to 20. p and q in the two Rf1 may be the same or different.)

[0219] (In the two Rf2 in formula (1J), r represents the average degree of polymerization and is 1 to 15. The r in the two Rf2 may be the same or different.)

[0220]

[0221] (In the two Rf2 in formula (1K), r represents the average degree of polymerization and is 1 to 15. The r in the two Rf2 may be the same or different.)

[0222] (In the two Rf1 in formula (1L), p and q represent the average degree of polymerization, p represents 1 to 20, and q represents 0 to 20. p and q in the two Rf1 may be the same or different.)

[0223] (In the two Rf1 in formula (1M), p and q represent the average degree of polymerization, p represents 1 to 20, and q represents 0 to 20. p and q in the two Rf1 may be the same or different.)

[0224] (In the two Rf2 in formula (1N), r represents the average degree of polymerization and is 1 to 15. The r in the two Rf2 may be the same or different.)

[0225] (In the two Rf1 in formula (1O), p and q represent the average degree of polymerization, p represents 1 to 20, and q represents 0 to 20. p and q in the two Rf1 may be the same or different.)

[0226]

[0227] (In the three Rf2 in formula (2A), r represents the average degree of polymerization and is 1 to 15. The r in the three Rf2 may be different from each other, or may be partially or entirely the same.)

[0228] (In the three Rf2 in formula (2B), r represents the average degree of polymerization and is 1 to 15. The r in the three Rf2 may be different from each other, or may be partially or entirely the same.)

[0229] (In the three Rf2 in formula (2C), r represents the average degree of polymerization and is 1 to 15. The r in the three Rf2 may be different from each other, or may be the same in part or in whole.)

[0230] (In the three Rf2 in formula (2D), r represents the average degree of polymerization and is 1 to 15. The r in the three Rf2 may be different from each other, or may be partially or entirely the same.)

[0231] (In the three Rf2 in formula (2E), r represents the average degree of polymerization and is 1 to 15. The r in the three Rf2 may be different from each other, or may be partially or entirely the same.)

[0232]

[0233] (In the three Rf2 in formula (2F), r represents the average degree of polymerization and is 1 to 15. The r in the three Rf2 may be different from each other, or may be partially or entirely the same.)

[0234] (In the three Rf1 in formula (2G), p and q represent the average degree of polymerization, p represents 1 to 20, and q represents 0 to 20. p and q in the three Rf1 may be different from each other, or may be partially or entirely the same.)

[0235] (In the three Rf1 in formula (2H), p and q represent the average degree of polymerization, p represents 1 to 20, and q represents 0 to 20. p and q in the three Rf1 may be different from each other, or may be partially or entirely the same.)

[0236] (In the three Rf1 in formula (2I), p and q represent the average degree of polymerization, p represents 1 to 20, and q represents 0 to 20. p and q in the three Rf1 may be different from each other, or may be the same in part or in whole.)

[0237] (In the three Rf2 in formula (2J), r represents the average degree of polymerization and is 1 to 15. The r in the three Rf2 may be different from each other, or may be partially or entirely the same.)

[0238]

[0239] (In the three Rf2 in formula (2K), r represents the average degree of polymerization and is 1 to 15. The r in the three Rf2 may be different from each other, or may be partially or entirely the same.)

[0240] (In the three Rf1 in formula (2L), p and q represent the average degree of polymerization, p represents 1 to 20, and q represents 0 to 20. p and q in the three Rf1 may be different from each other, or may be the same in part or in whole.)

[0241] (In the three Rf1 in formula (2M), p and q represent the average degree of polymerization, p represents 1 to 20, and q represents 0 to 20. p and q in the three Rf1 may be different from each other, or may be the same in part or in whole.)

[0242] (In the three Rf2 in formula (2N), r represents the average degree of polymerization and is 1 to 15. The r in the three Rf2 may be different from each other, or may be partially or entirely the same.)

[0243] (In the three Rf1 in formula (2O), p and q represent the average degree of polymerization, p represents 1 to 20, and q represents 0 to 20. p and q in the three Rf1 may be different from each other, or may be partially or entirely the same.)

[0244] 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, more preferably in the range of 500 to 5,000, and particularly preferably in the range of 1,000 to 3,000. If the number average molecular weight is above 500, the lubricant containing the fluorinated ether compound of the present embodiment is not easy to evaporate, and the lubricant can be prevented from evaporating and being transferred to the magnetic head. In addition, if the number average molecular weight is below 10,000, the viscosity of the fluorinated ether compound is appropriate, and a thin lubricating layer can be easily formed by applying the lubricant containing the fluorinated ether compound. If the number average molecular weight is below 5,000, it becomes a viscosity that is easy to handle when applied to a lubricant, and is therefore more preferred.

[0245] 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 19 The number average molecular weight is determined by calculating the number of repeating units of the PFPE chain from the integrated value measured by F-NMR. In the measurement of NMR (nuclear magnetic resonance), the sample is diluted with a single or mixed solvent such as hexafluorobenzene, d-acetone, d-tetrahydrofuran, etc. and used for the measurement. 19 The standard of 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.

[0246] The fluorine-containing ether compound of the present embodiment is preferably subjected to molecular weight fractionation by an appropriate method so that the molecular weight distribution (ratio of weight average molecular weight (Mw) / number average molecular weight (Mn)) is 1.3 or less.

[0247] In the present embodiment, the method for molecular weight fractionation is not particularly limited, and for example, molecular weight fractionation using silica gel column chromatography, gel permeation chromatography (GPC), or the like, molecular weight fractionation using supercritical extraction, or the like can be used.

[0248] "Manufacturing method"

[0249] 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.

[0250] Specifically, when producing a fluorine-containing ether compound in which z in formula (1) is 1, a production method selected from the first production method to the fourth production method shown below can be used. When producing a fluorine-containing ether compound in which z in formula (1) is 2, a production method selected from the fifth production method and the sixth production method shown below can be used.

[0251] <First Manufacturing Method>

[0252] In the manufacturing formula (1), z is 1, and R 1 With R 4 The same, is a group represented by formula (2-1), and a is 1, X 1 is a hydrogen atom, R 2 The two PFPE chains shown are identical, as R 3 In the case of a fluorine-containing ether compound in the formula (4) where h and i are 1, the production method represented by the following formula (8) can be used.

[0253]

[0254] (In formula (8), R 2 With R in formula (1) 2 PG1, PG2, and PG3 each represent a protecting group, which may be the same or different. X represents a (pseudo)halogen group. s, which represents the number of methylene groups, is an integer corresponding to b in formula (2-1). t, which represents the number of methylene groups, is an integer corresponding to X in formula (2-1). 2 (= integer corresponding to f in formula (3))

[0255] (First reaction)

[0256] Prepare R in formula (1) 2 The corresponding PFPE chain has a fluorine-based compound having hydroxymethyl groups (-CH2OH) at both ends. The first intermediate compound is produced by bonding an appropriate protective group (PG1) to the hydroxymethyl group at one end of the fluorine-based compound.

[0257] (Second reaction)

[0258] Next, the second intermediate compound is produced by reacting an epoxy compound having a hydroxyl group protected by a protecting group (PG2) with a hydroxymethyl group (—CH 2 OH) to which the protecting group (PG1) is not bonded in the first intermediate compound obtained by the first reaction.

[0259] The epoxy compound used in the second reaction has the same radical as -(CH2) in the group represented by formula (2-1). a -CH(OX 2 )-(CH2) b -OX 1 Specifically, as shown in formula (8), -(CH2) a -CH(OX 2 )-(CH2) b -OX 1 where a is 1, b is s and X 1 Such epoxy compounds can be produced by a known method, or commercially available products can be used.

[0260] (Third reaction)

[0261] Next, a (pseudo)halogenated alkyl compound (X-(CH2)) having a hydroxyl group protected by a protecting group (PG3) is reacted with tThen, the protective groups PG1, PG2, and PG3 contained in the obtained compound are deprotected under appropriate conditions to produce a compound having a reaction product with R 2 The corresponding PFPE chain has a single end with a residue equivalent to R 1 (=R 4 )'s terminal group.

[0262] The (pseudo)halogenated alkyl compound (X-(CH2)) used in the third reaction t -O-PG3) has the same structure as -OX in the group represented by formula (2-1) 2 (X 2 Specifically, as shown in formula (8), a group (-((CH2)) f -O) g -H) corresponds to the (pseudo)halogenated alkyl compound wherein f is t and g is 1. Such a (pseudo)halogenated alkyl compound can be produced by a known method, or a commercially available product can be used.

[0263] (Fourth reaction)

[0264] Finally, let R have the equivalent of a linker 3 The (pseudo) halogenated epoxy compound of the partial structure of the third intermediate compound contains the 2 The corresponding hydroxymethyl group (-CH2OH) at the end of the PFPE chain is reacted. In the first production method, the reaction ratio of the third intermediate compound to the (pseudo) halogenated epoxy compound is preferably about 2:1 (molar ratio).

[0265] The (pseudo) halogenated epoxy compound used in the fourth reaction has a group (-O(CH2) h -CH(OH)-(CH2) i Specifically, as shown in formula (8), a group (-O(CH2) h -CH(OH)-(CH2) i O-) corresponds to a (pseudo)halogenated epoxy compound in which h and i are 1. Such a (pseudo)halogenated epoxy compound can be produced by a known method, or a commercially available product can be used.

[0266] By performing the above steps, it is possible to produce a compound wherein z in formula (1) is 1 and R 1 With R 4 The same, is a group represented by formula (2-1), and a is 1, X 1is a hydrogen atom, R 2 The two PFPE chains shown are identical, as R 3 A fluorine-containing ether compound wherein h and i in the formula (4) are 1.

[0267] In the above-mentioned first production method, in the third reaction, the case where all the protecting groups PG1, PG2, and PG3 contained in the compound are deprotected is given as an example, but it is also possible to deprotect only the protecting group PG1 in the third reaction, and deprotect the protecting groups PG2 and PG3 under appropriate conditions after the fourth reaction.

[0268] In the first production method, as the epoxy compound used in the second reaction, there is used an epoxy compound represented by the formula (2-1) wherein a is 1, X 1 The case of an epoxy compound corresponding to a substance having a hydrogen atom is described as an example, but it is also possible to use an epoxy compound corresponding to a substance having a hydrogen atom 1 The epoxy compound corresponding to the substance represented by the group of formula (3). 1 The epoxy compound corresponding to the substance represented by the formula (3) can be produced by a known method, or a commercially available product can be used.

[0269] In addition, in the above-mentioned first production method, as the (pseudo) halogenated alkyl compound (X-(CH2) t -O-PG3), for example, the group (-((CH2) f -O) g -H) is described as an example of a (pseudo)halogenated alkyl compound corresponding to a substance in which f is t and g is 1, but a (pseudo)halogenated alkyl compound corresponding to a substance in which g is 2 in a group represented by formula (3) can also be used. The (pseudo)halogenated alkyl compound corresponding to a substance in which g is 2 in a group represented by formula (3) can be produced by a known method, or a commercially available product can be used.

[0270] <Second manufacturing method>

[0271] In the manufacturing formula (1), z is 1, and R 1 With R 4 The same, and R 2 The two PFPE chains shown are identical, as R 3 In the case of a fluorine-containing ether compound in which h and i in the formula (4) are 1, the method represented by the following formula (9) can be used.

[0272]

[0273] (In formula (9), R 2 With R in formula (1) 2PG4 represents a protecting group. LG represents a leaving group obtained by reacting an activating agent with a hydroxyl group. R represents a group having a structure equivalent to R in formula (1) 1 (=R 4 ) of -(CH2) x -CH(R 5 )R 6 X represents a (pseudo) halogen group.

[0274] (First reaction)

[0275] The same operation as the first reaction in the first production method is carried out to produce a 2 The corresponding first intermediate compound has a protecting group (PG4) bonded to one end of the PFPE chain.

[0276] (Second reaction)

[0277] Next, a known activating agent is reacted with the hydroxymethyl group at one terminal in the first intermediate compound obtained by the first reaction to produce a second intermediate compound in which the terminal opposite to the protecting group (PG4) of the first intermediate compound is converted into a leaving group (LG).

[0278] As the leaving group (LG), for example, a chloro group, a bromo group, an iodo group, a p-toluenesulfonyloxy group, a methanesulfonyloxy group, a trifluoromethanesulfonyloxy group, a perfluoroalkylsulfonyloxy group, a nitrobenzenesulfonyloxy group or the like can be used.

[0279] (Third reaction)

[0280] Next, make the inclusion equivalent to R 1 (=R 4 ) of -(CH2) x -CH(R 5 )R 6 After the alcohol compound (R-OH) of the partial structure of the second intermediate compound obtained by the second reaction reacts with the leaving group (LG) to connect the terminal group, the protecting group (PG4) is deprotected by an appropriate method. 2 The corresponding PFPE chain has a single end with a residue equivalent to R 1 (=R 4 ) of -(CH2) x -CH(R 5 )R 6 The alcohol compound used in the third reaction can be produced by a known method, or a commercially available product can be used.

[0281] (Fourth reaction)

[0282] Finally, let R have the equivalent of a linker 3 The (pseudo) halogenated epoxy compound of the partial structure of the third intermediate compound contains the 2 The corresponding hydroxymethyl group (-CH2OH) at the end of the PFPE chain is reacted. For the second production method, it is preferred that the reaction ratio of the third intermediate compound to the (pseudo) halogenated epoxy compound is about 2:1 (molar ratio).

[0283] As the (pseudo)halogenated epoxy compound used in the fourth reaction, the same compounds as those that can be used in the fourth reaction of the first production method can be used.

[0284] By performing the above steps, the z in formula (1) is 1, and R 1 With R 4 The same, and R 2 The two PFPE chains shown are identical, as R 3 A fluorine-containing ether compound wherein h and i in the formula (4) are 1.

[0285] The compound used in the third reaction of the second production method described above, which contains a compound corresponding to R 1 (=R 4 ) of -(CH2) x -CH(R 5 )R 6 Among the polar groups contained in the alcohol compound having a partial structure of , the polar group that does not participate in the bonding with the second intermediate compound in the third reaction can be used in the third reaction after being protected by an appropriate protecting group. In this case, the protecting group of the polar group can be deprotected under appropriate conditions after the third reaction or after the fourth reaction.

[0286] <Third Manufacturing Method>

[0287] In the manufacturing formula (1), z is 1, and R 1 With R 4 The same, and R 2 The two PFPE chains shown are identical, as R 3 In the case of a fluorine-containing ether compound in which h and i in the formula (4) are 1, the method represented by the following formula (10) can be used.

[0288]

[0289] (In formula (10), R 2 With R in formula (1) 2 X represents a (pseudo) halogen group. R' represents a group having the same 1 (=R 4 ) of -(CH2) x-CH(R 5 )R 6 The organic radical of the partial structure.

[0290] (First reaction)

[0291] Prepare R in formula (1) 2 The corresponding PFPE chain has hydroxymethyl (-CH2OH) fluorine-based compounds at both ends. 1 (=R 4 ) of -(CH2) x -CH(R 5 )R 6 The (pseudo) halogenated alkyl compound (X-R') of the partial structure of the fluorine-based compound reacts with the hydroxymethyl group at one end to connect the terminal group. 2 The corresponding PFPE chain has a single end with a residue equivalent to R 1 (=R 4 ) of -(CH2) x -CH(R 5 )R 6 The first intermediate compound having a terminal group corresponding to R 1 (=R 4 ) of -(CH2) x -CH(R 5 )R 6 The (pseudo)halogenated alkyl compound with a partial structure of can be produced by a known method, or a commercially available product can be used.

[0292] (Second reaction)

[0293] Next, make the linker R 3 The (pseudo) halogenated epoxy compound of the partial structure of the first intermediate compound contains the 2 The corresponding hydroxymethyl group (-CH2OH) at the end of the PFPE chain is reacted. In the third production method, the reaction ratio of the first intermediate compound to the (pseudo) halogenated epoxy compound is preferably about 2:1 (molar ratio).

[0294] As the (pseudo)halogenated epoxy compound used in the second reaction, the same compounds as those that can be used in the fourth reaction of the first production method can be used.

[0295] By performing the above steps, the z in formula (1) is 1, and R 1 With R 4 The same, and R 2 The two PFPE chains shown are identical, as R 3 A fluorine-containing ether compound wherein h and i in the formula (4) are 1.

[0296] The compound used in the first reaction of the third production method comprises a compound corresponding to R 1 (=R 4 ) of -(CH2) x -CH(R 5 )R 6 Among the polar groups contained in the (pseudo)halogenated alkyl compound of the partial structure, the polar group that does not participate in the combination with the fluorine-based compound in the first reaction can be used in the first reaction after being protected by an appropriate protecting group. In this case, the protecting group of the polar group can be deprotected under appropriate conditions after the first reaction or after the second reaction.

[0297] For the fourth reaction of the first production method, the fourth reaction of the second production method, and the second reaction of the third production method, examples of the (pseudo) halogenated epoxy compound include the use of a group (-O(CH2)) represented by formula (4) h -CH(OH)-(CH2) i The case of a (pseudo)halogenated epoxy compound corresponding to a substance in which h and / or i in the group represented by formula (O-) are 1 is described as an example, but a (pseudo)halogenated epoxy compound or (pseudo)halogenated alkyl compound corresponding to a substance in which h and / or i in the group represented by formula (4) are 2 or 3 can also be used. The (pseudo)halogenated epoxy compound or (pseudo)halogenated alkyl compound corresponding to a substance in which h and / or i in the group represented by formula (4) are 2 or 3 can be manufactured by a known method.

[0298] <Fourth Manufacturing Method>

[0299] In the manufacturing formula (1), z is 1, and R 1 With R 4 The terminal group shown, or R 2 When at least one of the two PFPE chains shown is a different fluorine-containing ether compound, the production method shown below can be used.

[0300] (First reaction)

[0301] The same method as the first to third manufacturing methods is used to manufacture the 1 Side R 2 The corresponding PFPE chain has a single end with a residue equivalent to R 1 A first intermediate compound having a terminal group.

[0302] (Second reaction)

[0303] Next, make the linker R 3 The (pseudo) halogenated epoxy compound of the partial structure of the first intermediate compound contains the1 Side R 2 The hydroxymethyl group (-CH2OH) at the end of the corresponding PFPE chain is reacted. For the fourth production method, it is preferred that the reaction ratio of the first intermediate compound to the (pseudo) halogenated epoxy compound is about 1:1 (molar ratio). 1 Side R 2 One end of the corresponding PFPE chain has a 1 The terminal group has a connecting group R 3 As the (pseudo)halogenated epoxy compound, the same substances as those that can be used in the fourth reaction of the first production method can be used.

[0304] (Third reaction)

[0305] Next, the same operation as the first intermediate compound is carried out to prepare 4 Side R 2 The corresponding PFPE chain has a single end with a residue equivalent to R 4 A third intermediate compound having a terminal group.

[0306] In the fourth manufacturing method, when manufacturing R 4 In the case of a fluorine-containing ether compound which is not a branched terminal group represented by formula (2), it has a 4 The third intermediate compound having a terminal group of can be prepared, for example, by the method shown below. That is, the following method can be used, that is, preparing a 2 The corresponding PFPE chain has a fluorine-based compound having hydroxymethyl groups (-CH2OH) at both ends, and a method in which a compound containing a structure corresponding to any group represented by formula (6-1) to formula (6-3) is reacted with the hydroxymethyl group at one end by a known method.

[0307] (Fourth reaction)

[0308] Then, by reacting the second intermediate compound with the third intermediate compound, a compound (1) in which z is 1 and R 1 With R 4 The terminal group shown, or R 2 Among the two PFPE chains shown, at least one is a different fluorinated ether compound.

[0309] In the first intermediate compound produced by the first reaction of the fourth production method and the third intermediate compound produced by the third reaction, the terminal group R 1 and / or terminal group R 4The polar group contained may be protected by an appropriate protecting group. In this case, the protecting group of the polar group may be deprotected under appropriate conditions after the second reaction or the fourth reaction.

[0310] In the fourth production method, the first reaction, the second reaction, and the third reaction are performed in this order. However, the third reaction may be performed before the first reaction or between the first reaction and the second reaction, and is not particularly limited.

[0311] In addition, in the fourth production method, in the second reaction, the first intermediate compound obtained in the first reaction is used, and the third intermediate compound obtained in the third reaction may be used instead of the first intermediate compound. In this case, in the fourth reaction, the first intermediate compound may be used instead of the third intermediate compound.

[0312] <Fifth Manufacturing Method>

[0313] In the manufacturing formula (1), z is 2, R 2 The three PFPE chains shown are identical, with two connecting groups R 3 Same, R 1 With R 4 In the case of a fluorine-containing ether compound having the same terminal group as shown, or in the manufacturing formula (1), z is 2, R 2 Among the three PFPE chains shown, only the central R 2 Different, 2 connecting groups R 3 Same, R 1 With R 4 In the case of the fluorine-containing ether compounds having the same terminal groups as shown above, the production method shown below can be used.

[0314] (First reaction)

[0315] The same method as in the first to fourth manufacturing methods is performed to manufacture a 1 Side R 2 (=R 4 Side R 2 ) corresponds to a single end of the PFPE chain having a residue equivalent to R 1 (=R 4 )'s terminal group.

[0316] (Second reaction)

[0317] Prepare R at the center of the molecule in formula (1) 2 The corresponding PFPE chain has a fluorine compound with a hydroxymethyl group (-CH2OH) at both ends. Next, the hydroxyl groups of the hydroxymethyl groups at both ends of the fluorine compound are connected to a fluorine compound having a connecting group R3 Reaction of partially structured (pseudo)halogenated epoxides.

[0318] In the fifth production method, it is preferred that the reaction ratio of the fluorine-based compound to the (pseudo) halogenated epoxy compound be about 1:2 (molar ratio). 2 The two ends of the corresponding PFPE chain are connected with a linker group R 3 As the (pseudo)halogenated epoxy compound, the same substances as those that can be used in the fourth reaction of the first production method can be used.

[0319] (Third reaction)

[0320] Finally, the first intermediate compound and the second intermediate compound are mixed and reacted. In the fifth production method, the reaction ratio of the first intermediate compound to the second intermediate compound is preferably about 2:1 (molar ratio).

[0321] By carrying out the above steps, it is possible to produce a compound in which z in formula (1) is 2 and R 2 The three PFPE chains shown are identical, with two connecting groups R 3 Same, R 1 With R 4 The fluorine-containing ether compound having the same terminal group as shown, or z in formula (1) is 2, R 2 Among the three PFPE chains shown, only the central R 2 Different, 2 connecting groups R 3 Same, R 1 With R 4 The fluorine-containing ether compounds shown have the same terminal groups.

[0322] In the first intermediate compound produced by the first reaction of the fifth production method, the terminal group R 1 (=R 4 ) The polar group contained in the reaction mixture can be protected by an appropriate protecting group. In this case, the protecting group of the polar group can be deprotected under appropriate conditions after the first reaction or after the third reaction.

[0323] In the fifth production method described above, the second reaction is performed after the first reaction, but the first reaction may be performed after the second reaction.

[0324] <Sixth Manufacturing Method>

[0325] In the manufacturing formula (1), z is 2, and the two connecting groups R 3 Same, R 1 and R 4When the terminal groups shown above and at least one of the three PFPE chains is a different fluorinated ether compound, the production method shown below can be used.

[0326] (First reaction)

[0327] In the same manner as in the case of producing the second intermediate compound in the second reaction of the fifth production method, a compound having a molecular center R in formula (1) is produced. 2 The two ends of the corresponding PFPE chain have a linker R 3 The first intermediate compound has a partial structure of an epoxy group.

[0328] (Second reaction, third reaction)

[0329] The same method as in the first to fifth manufacturing methods is used to manufacture the 1 Side R 2 The corresponding PFPE chain has a single end with a residue equivalent to R 1 The second intermediate compound of the terminal group, and in the 4 Side R 2 The corresponding PFPE chain has a single end with a residue equivalent to R 4 A third intermediate compound having a terminal group.

[0330] (Fourth reaction, fifth reaction)

[0331] A fourth reaction of reacting the first intermediate compound obtained by the first reaction with the second intermediate compound and a fifth reaction of reacting the fourth intermediate compound obtained by the fourth reaction with the third intermediate compound are sequentially performed.

[0332] By carrying out the above steps, it is possible to produce a compound wherein z in formula (1) is 2 and two linking groups R 3 Same, R 1 and R 4 The terminal groups shown, any one or more different fluorinated ether compounds among the three PFPE chains.

[0333] In the second intermediate compound and the third intermediate compound produced by the second reaction and the third reaction of the sixth production method, the terminal group R 1 and / or R 4 The polar group contained may be protected by an appropriate protecting group. In this case, the protecting group of the polar group may be deprotected under appropriate conditions at any stage after the second reaction to the fifth reaction.

[0334] In the sixth production method, the first reaction, the second reaction, and the third reaction are performed in this order. However, the first reaction may be performed between the second reaction and the third reaction or after the third reaction, and is not particularly limited.

[0335] In the sixth production method, the second intermediate compound is used in the fourth reaction and the third intermediate compound is used in the fifth reaction. However, the third intermediate compound may be used in the fourth reaction and the second intermediate compound may be used in the fifth reaction.

[0336] As the (pseudo)halogen group (X) contained in the (pseudo)halogenated alkyl compound and the (pseudo)halogenated epoxy compound used in the above-mentioned first to sixth manufacturing methods, for example, at least one selected from the group consisting of a chloro group, a bromo group, an iodo group, a p-toluenesulfonyloxy group, a methanesulfonyloxy group, a trifluoromethanesulfonyloxy group, a perfluoroalkylsulfonyloxy group, and a nitrobenzenesulfonyloxy group can be used.

[0337] [Lubricant for magnetic recording media]

[0338] The lubricant for a magnetic recording medium according to the present embodiment contains a fluorine-containing ether compound represented by formula (1).

[0339] The lubricant of the present embodiment may be mixed with known materials used as lubricant materials as needed, as long as the properties due to the inclusion of the fluorine-containing ether compound represented by the above formula (1) are not impaired.

[0340] 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 500 to 10,000.

[0341] When the lubricant of the present embodiment contains a material other than the fluorinated ether compound represented by formula (1), the content of the fluorinated ether compound represented by formula (1) in the lubricant of the present embodiment is preferably 50% by mass or more, more preferably 70% by mass or more. The content of the fluorinated ether compound represented by formula (1) may be 80% by mass or more, or 90% by mass or more.

[0342] Since the lubricant of this embodiment contains the fluorine-containing ether compound represented by the above formula (1), it can form a lubricating layer having excellent adhesion to the protective layer and good coverage by covering the surface of the protective layer at a high coverage rate even if the thickness is thin. Therefore, according to the lubricant of this embodiment, a lubricating layer having excellent wear resistance and smoothness can be formed even if the thickness is thin.

[0343] [Magnetic recording media]

[0344] 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.

[0345] 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, an adhesion layer and / or a soft magnetic layer may be provided between the underlayer and the substrate.

[0346] Figure 1 This is a schematic cross-sectional view showing one embodiment of the magnetic recording medium of the present invention.

[0347] 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 .

[0348] "Substrate"

[0349] 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.

[0350] 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.

[0351] "Attachment Layer"

[0352] 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.

[0353] 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.

[0354] "Soft magnetic layer"

[0355] The soft magnetic layer 13 preferably has a structure in which a first soft magnetic film, an intermediate layer composed of a Ru film, and a second soft magnetic film are stacked in sequence. That is, the soft magnetic layer 13 preferably has a structure in which the upper and lower soft magnetic films of the intermediate layer are antiferrocoupled (AFC) by sandwiching an intermediate layer composed of a Ru film between two soft magnetic films.

[0356] Examples of the material of the first soft magnetic film and the second soft magnetic film include CoZrTa alloy and CoFe alloy.

[0357] 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. Thus, the amorphization of the first soft magnetic film and the second soft magnetic film is promoted. 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.

[0358] The soft magnetic layer 13 can be formed by, for example, sputtering.

[0359] "1st base layer"

[0360] 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.

[0361] 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.

[0362] The first base layer 14 can be formed by, for example, sputtering.

[0363] "Second base layer"

[0364] The second underlayer 15 is a layer 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.

[0365] 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.

[0366] The second base layer 15 can be formed by, for example, sputtering.

[0367] "Magnetic layer"

[0368] The magnetic layer 16 is composed 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.

[0369] 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 .

[0370] The magnetic layer 16 may be composed of a single layer or a plurality of magnetic layers formed of materials having different compositions.

[0371] 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.

[0372] 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.

[0373] 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.

[0374] 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.

[0375] 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.

[0376] 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.

[0377] The non-magnetic layer can be formed by, for example, sputtering.

[0378] 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.

[0379] 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.

[0380] "Protective layer"

[0381] The protective layer 17 protects the magnetic layer 16. The protective layer 17 may be composed of one layer or multiple layers. Examples of the material of the protective layer 17 include carbon, carbon containing nitrogen, silicon carbide, and the like. 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 contained in the fluorine-containing ether compound in the lubricating layer 18 is further enhanced, and therefore, it is preferred.

[0382] 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).

[0383] 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. For example, the carbon-based protective layer is 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.

[0384] The thickness of the protective layer 17 is preferably 1 nm to 7 nm. When the thickness of the protective layer 17 is 1 nm or more, sufficient performance as the protective layer 17 is obtained. When the thickness of the protective layer 17 is 7 nm or less, it is preferred from the viewpoint of reducing the thickness of the protective layer 17.

[0385] 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.

[0386] 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.

[0387] "Lubricating layer"

[0388] 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.

[0389] Lubricating layer 18 Figure 1 As shown, the lubricating layer 18 is formed in contact with the protective layer 17. The lubricating layer 18 contains the above-mentioned fluorine-containing ether compound.

[0390] 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.

[0391] 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.

[0392] When the surface of the protective layer 17 is not covered with a sufficiently high coverage rate by the lubricating layer 18, the environmental substances adsorbed on the surface of the magnetic recording medium 10 penetrate the gaps of the lubricating layer 18 and invade the lower layer of the lubricating layer 18. The environmental substances that invade the lower layer of the lubricating layer 18 are adsorbed and combined with the protective layer 17 to generate pollutants. Furthermore, during magnetic recording and reproducing, the pollutants (agglomerated components) are attached (transferred) to the magnetic head as stains, causing damage to the magnetic head or reducing the magnetic recording and reproducing characteristics of the magnetic recording and reproducing device.

[0393] Environmental substances that cause pollutants to be generated include, for example, siloxane compounds (cyclic siloxane, linear siloxane), ionic impurities, hydrocarbons with high molecular weights such as octacosane, plasticizers such as dioctyl phthalate, etc. Metal ions included in ionic impurities include, for example, sodium ions, potassium ions, etc. Inorganic ions included in ionic impurities include, for example, chloride ions, bromide ions, nitrate ions, sulfate ions, ammonium ions, etc. Organic ions included in ionic impurities include, for example, oxalate ions, formate ions, etc.

[0394] "Method for forming a lubricating layer"

[0395] 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.

[0396] 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.

[0397] Examples of the solvent used in the lubricating layer forming solution include fluorine-based solvents such as Batler (registered trademark) XF (trade name, manufactured by Mitsui Dupont Fluoro Chemical Co., Ltd.) and / or Asahicrine (registered trademark) AE-3000 (trade name, manufactured by AGC Corporation).

[0398] 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.

[0399] 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.

[0400] 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.

[0401] 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.

[0402] The heat treatment temperature is preferably 100 to 180° 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 can be prevented. The heat treatment time is preferably 10 to 120 minutes.

[0403] 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. The lubricating layer 18 has excellent adhesion to the protective layer 17, and even if the thickness is thin, the surface of the protective layer 17 can be coated with a high coverage rate, and has excellent wear resistance and smoothness. Therefore, for the magnetic recording medium 10 of the present embodiment, the magnetic head can be stably floated, and the long-term reliability and durability are good.

[0404] Example

[0405] 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.

[0406] [Example 1]

[0407] The compound represented by the above formula (1A) was obtained by the method shown below.

[0408] (Process for producing the first intermediate compound (1A-1))

[0409] In a 300 mL eggplant flask under nitrogen atmosphere, add HOCH2CF2CF2O (CF2CF2CF2O) r20 g of a compound represented by CF2CF2CH2OH (where r in the formula represents the average degree of polymerization is 3.8) (number average molecular weight 909, molecular weight distribution 1.1), 1.95 g of 3,4-dihydro-2H-pyran, and 44 mL of a mixed solution (volume ratio 1:1) of Asahiklin (registered trademark) AE-3000 (manufactured by AGC Co., Ltd.) and dichloromethane as a fluorine-based solvent were stirred at 0°C until it became uniform to prepare a mixed solution. 0.084 g of p-toluenesulfonic acid monohydrate was added to the mixed solution, and after stirring at 0°C for 30 minutes, it was stirred at room temperature for 2 hours to react.

[0410] The reaction product obtained after the reaction was cooled to 0°C, and 50 mL of saturated sodium bicarbonate water was added to stop the reaction. The resulting reaction solution was transferred to a separatory funnel and extracted three times with 100 mL of ethyl acetate. The organic layer was washed with saline 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 10.8 g of the compound represented by the following formula (11) as the first intermediate compound (1A-1).

[0411]

[0412] (In formula (11), THP represents a tetrahydropyranyl group, and r representing an average degree of polymerization represents 3.8.)

[0413] (Process for producing the second intermediate compound (1A-2))

[0414] In a 100 mL eggplant flask under a nitrogen atmosphere, 10.0 g (number average molecular weight 993, 10.1 mmol) of the compound represented by formula (11) as the first intermediate compound (1A-1), 1.9 g (molecular weight 158, 12.1 mmol) of the compound represented by the following formula (12) as the epoxy compound (A-1), and 20 mL of tert-butyl alcohol were added, and stirred at room temperature to prepare a mixed solution. 0.2 g (molecular weight 112, 2.0 mmol) of potassium tert-butylate was added to the mixed solution, and the mixture was stirred at 70° C. for 5 hours to react.

[0415]

[0416] (In formula (12), THP represents tetrahydropyranyl.)

[0417] 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 10.0 g of a compound represented by the following formula (13) as a second intermediate compound (1A-2).

[0418]

[0419] (In formula (13), THP represents a tetrahydropyranyl group, Rf2 is represented by the above formula, and r representing the average degree of polymerization in Rf2 is 3.8.)

[0420] (Process for producing the third intermediate compound (1A-3))

[0421] In a 100 mL eggplant flask under a nitrogen atmosphere, 10.0 g (number average molecular weight 1151, 8.7 mmol) of the compound represented by formula (13) as the second intermediate compound (1A-2), 2.7 g (molecular weight 209, 13.0 mmol) of the compound (A-2) represented by the following formula (14) as the (pseudo) halogenated alkyl compound, and 29 mL of N,N-dimethylformamide (DMF) were added, and stirred at 0°C until the mixture became uniform. 0.70 g (molecular weight 24, 17.4 mmol) of sodium hydride was further added to the uniform liquid, and the mixture was stirred at 40°C for 10 hours to react.

[0422]

[0423] (In formula (14), THP represents tetrahydropyranyl.)

[0424] The reaction solution obtained after the reaction was returned to room temperature, 23 g of 10% hydrogen chloride / methanol solution (hydrogen chloride-methanol reagent (5-10%) manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and stirred at room temperature for 2 hours. The reaction solution was transferred little by little to a separatory funnel added with 100 mL of brine, and extracted three times 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 filtering and separating the desiccant, the filtrate was concentrated and the residue was refined by silica gel column chromatography. By performing the above steps, 6.5 g of the compound represented by the following formula (15) was obtained as the third intermediate compound (1A-3).

[0425]

[0426] (In formula (15), Rf2 is represented by the above formula, and r representing the average degree of polymerization in Rf2 is 3.8.)

[0427] (Process for producing compound (1A))

[0428] In a 100 mL eggplant flask under a nitrogen atmosphere, 6.5 g (number average molecular weight 1155, 5.6 mmol) of the compound represented by formula (15) as the third intermediate compound (1A-3), 0.39 g (molecular weight 137, 2.8 mmol) of epibromohydrin as a (pseudo) halogenated epoxy compound, and 11 mL of N,N-dimethylformamide (DMF) were added, and stirred at room temperature to prepare a mixed solution. 2.7 g (molecular weight 325, 8.4 mmol) of cesium carbonate was added to the mixed solution, and the mixture was stirred at 70°C for 8 hours to react.

[0429] 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 compound (1A) (in the two Rf2 in formula (1A), r representing the average degree of polymerization is 3.8.) 4.5 g (number average molecular weight 2110).

[0430] The obtained compound (1A) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0431] 1 H-NMR(CD3COCD3): δ[ppm]3.39-4.35(36H)

[0432] 19 F-NMR (CD3COCD3): δ [ppm] -84.0~-83.0(30.4F), -86.4(8F), -124.3(8F), -130.0~-129.0(15.2F)

[0433] [Example 2]

[0434] In the manufacturing process of the third intermediate compound (1A-3) in Example 1, 2.9 g (molecular weight 223, 13.0 mmol) of the compound (B-1) represented by the following formula (16) as a (pseudo) halogenated alkyl compound was used instead of the compound (A-2) represented by formula (14). Except for this, the same operation as in Example 1 was carried out to obtain 4.6 g (number average molecular weight 2138) of compound (1B) (in the two Rf2 in formula (1B), r representing the average degree of polymerization is 3.8).

[0435]

[0436] (In formula (16), THP represents tetrahydropyranyl.)

[0437] The obtained compound (1B) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0438] 1 H-NMR (CD3COCD3): δ [ppm] 1.56-1.80 (4H), 3.38-4.35 (36H)

[0439] 19 F-NMR (CD3COCD3): δ [ppm] -84.0~-83.1(30.4F), -86.4(8F), -124.2(8F), -130.1~-129.0(15.2F)

[0440] [Example 3]

[0441] In the manufacturing process of the second intermediate compound (1A-2) in Example 1, 2.1 g (molecular weight 172, 12.1 mmol) of the compound (C-1) represented by the following formula (17) synthesized as an epoxy compound by the following method was used instead of the compound (A-1) represented by the above formula (12). Except for this, the same operation as in Example 1 was performed to obtain 4.6 g (number average molecular weight 2138) of compound (1C) (in the two Rf2 in formula (1C), r representing the average degree of polymerization is 3.8).

[0442]

[0443] (In formula (17), THP represents tetrahydropyranyl.)

[0444] The compound (C-1) represented by the formula (17) is obtained by protecting the hydroxyl group of 3-buten-1-ol with 3,4-dihydro-2H-pyran and oxidizing the double bond of the obtained compound.

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

[0446] 1 H-NMR(CD3COCD3): δ[ppm]1.50-1.86(4H), 3.39-4.38(36H)

[0447] 19 F-NMR (CD3COCD3): δ [ppm] -84.0~-82.9(30.4F), -86.3(8F), -124.1(8F), -130.1~-129.0(15.2F)

[0448] [Example 4]

[0449] In the manufacturing process of the second intermediate compound (1A-2) in Example 1, 2.1 g (molecular weight 172, 12.1 mmol) of the compound (D-1) represented by the following formula (18) synthesized as an epoxy compound by the following method was used instead of the compound (A-1) represented by the above formula (12). Except for this, the same operation as in Example 1 was performed to obtain 4.4 g (number average molecular weight 2166) of compound (1D) (in the two Rf2 in formula (1D), r representing the average degree of polymerization is 3.8).

[0450]

[0451] (In formula (18), THP represents tetrahydropyranyl.)

[0452] The compound (D-1) represented by the formula (18) is obtained by protecting the hydroxyl group of 4-penten-1-ol with 3,4-dihydro-2H-pyran and oxidizing the double bond of the obtained compound.

[0453] The obtained compound (1D) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0454] 1 H-NMR(CD3COCD3): δ[ppm]1.44-1.85(8H), 3.35-4.45(36H)

[0455] 19F-NMR (CD3COCD3): δ [ppm] -84.0~-83.1(30.4F), -86.4(8F), -124.1(8F), -130.0~-128.8(15.2F)

[0456] [Example 5]

[0457] In the manufacturing process of the second intermediate compound (1A-2) in Example 1, 2.4 g (molecular weight 202, 12.1 mmol) of the compound (E-1) represented by the following formula (19) synthesized as an epoxy compound by the following method was used instead of the compound (A-1) represented by the above formula (12). Except for this, the same operation as in Example 1 was performed to obtain 4.5 g (number average molecular weight 2198) of compound (1E) (in the two Rf2 in formula (1E), r representing the average degree of polymerization is 3.8).

[0458]

[0459] (In formula (19), THP represents tetrahydropyranyl.)

[0460] The compound (E-1) represented by the formula (19) is obtained by protecting the hydroxyl group of ethylene glycol monoallyl ether with 3,4-dihydro-2H-pyran and oxidizing the double bond of the obtained compound.

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

[0462] 1 H-NMR(CD3COCD3): δ[ppm]3.30-4.52(44H)

[0463] 19 F-NMR (CD3COCD3): δ [ppm] -84.2~-83.0(30.4F), -86.5(8F), -124.0(8F), -130.0~-129.0(15.2F)

[0464] [Example 6]

[0465] In the manufacturing process of the second intermediate compound (1A-2) in Example 1, 2.4 g (molecular weight 200, 12.1 mmol) of the compound (F-1) represented by the following formula (20) synthesized as an epoxy compound by the following method was used instead of the compound (A-1) represented by the above formula (12). Except for this, the same operation as in Example 1 was performed to obtain 4.5 g (number average molecular weight 2194) of compound (1F) (in the two Rf2 in formula (1F), r representing the average degree of polymerization is 3.8).

[0466]

[0467] (In formula (20), THP represents tetrahydropyranyl.)

[0468] The compound (F-1) represented by the formula (20) is obtained by protecting the hydroxyl group of 5-hexen-1-ol with 3,4-dihydro-2H-pyran and oxidizing the double bond of the obtained compound.

[0469] The obtained compound (1F) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0470] 1 H-NMR(CD3COCD3): δ[ppm]1.25-1.78(12H), 3.40-4.38(36H)

[0471] 19 F-NMR (CD3COCD3): δ [ppm] -84.0~-83.1(30.4F), -86.4(8F), -124.1(8F), -130.1~-129.0(15.2F)

[0472] [Example 7]

[0473] In the production process of the first intermediate compound (1A-1) in Example 1, HOCH2CF2CF2O (CF2CF2CF2O) was replaced with r CF2CF2CH2OH (where r represents the average degree of polymerization is 3.8.), while HOCH2CF2O (CF2CF2O) is used p (CF2O) q The first intermediate compound (1G-1) was synthesized by adding 20 g of a compound represented by CF2CH2OH (wherein p representing the average polymerization degree is 4.0, and q representing the average polymerization degree is 4.0) (number average molecular weight 906, molecular weight distribution 1.1).

[0474] Then, in the production process of the second intermediate compound (1A-2) in Example 1, 2.4 g (molecular weight 200, 12.1 mmol) of the compound (F-1) represented by the above formula (20) as an epoxy compound was used instead of the compound (A-1) represented by the formula (12), and in the production process of the third intermediate compound (1A-3), 2.8 g (molecular weight 223, 12.6 mmol) of the compound (B-1) represented by the above formula (16) as a (pseudo)halogenated alkyl compound was used instead of the compound (A-2) represented by the formula (14). Except for this, the same operation as in Example 1 was performed to obtain 4.3 g (number average molecular weight 2217) of the compound represented by the above formula (1G) (in the two Rf1s in formula (1G), p representing the average degree of polymerization is 4.0, and q representing the average degree of polymerization is 4.0).

[0475] The obtained compound (1G) 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(CD3COCD3): δ[ppm]1.37-1.85(16H), 3.36-4.46(26H)

[0477] 19 F-NMR (CD3COCD3): δ [ppm] -55.6~-50.6(16F), -77.7(4F), -80.3(4F), -91.0~-88.4(32F)

[0478] [Example 8]

[0479] (Process for producing the first intermediate compound (1H-1))

[0480] By carrying out the same operation as the production step of the first intermediate compound (1G-1) in Example 7, the first intermediate compound (1H-1) represented by the following formula (21) was synthesized.

[0481]

[0482] (In formula (21), THP represents a tetrahydropyranyl group, p representing an average degree of polymerization is 4.0, and q representing an average degree of polymerization is 4.0.)

[0483] (Process for producing the second intermediate compound (1H-2))

[0484] In a 100 mL eggplant flask under a nitrogen atmosphere, 10.0 g of the first intermediate compound (1H-1) represented by formula (21), 3.3 g of pyridine (molecular weight 79, 15.2 mmol), and 10 mL of dichloromethane were added, and stirred at 0°C until it became uniform to prepare a mixed solution. 3.4 g of nonafluorobutanesulfonyl fluoride (molecular weight 302, 11.1 mmol) was added to the mixed solution, and after stirring at 0°C for 30 minutes, it was stirred at room temperature for 2 hours to react.

[0485] The reaction product obtained after the reaction was cooled to 25°C and neutralized with a 5% aqueous citric acid solution. The mixture 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 filtered and separated, the filtrate was concentrated and the residue was purified by silica gel column chromatography to obtain 12.0 g of a compound represented by the following formula (22) as a second intermediate compound (1H-2).

[0486]

[0487] (In formula (22), THP represents a tetrahydropyranyl group, and Nf represents a nonafluorobutanesulfonyl group. Rf1 is represented by the above formula, and p representing the average degree of polymerization in Rf1 represents 4.0, and q representing the average degree of polymerization represents 4.0.)

[0488] (Process for producing the third intermediate compound (1H-3))

[0489] In a 100 mL eggplant flask under a nitrogen atmosphere, 12.0 g (number average molecular weight 1272, 9.4 mmol) of the compound represented by formula (22) as the second intermediate compound (1H-2), 1.9 g (molecular weight 132, 14.2 mmol) of the compound (H-1) represented by the following formula (23) as the alcohol compound, and 19 mL of N,N-dimethylformamide (DMF) were added, and stirred at 0° C. until the mixture became uniform. 0.76 g (molecular weight 24, 8.9 mmol) of sodium hydride was further added to the uniform liquid, and the mixture was stirred at 40° C. for 10 hours to react.

[0490]

[0491] The reaction solution obtained after the reaction was returned to room temperature, 25 g of 10% hydrogen chloride / methanol solution (hydrogen chloride-methanol reagent (5-10%) manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and stirred at room temperature for 2 hours. The reaction solution was transferred little by little to a separatory funnel added with 100 mL of brine, and extracted three times 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 filtering and separating the desiccant, the filtrate was concentrated and the residue was refined by silica gel column chromatography. By performing the above steps, 6.5 g of the compound represented by the following formula (24) was obtained as the third intermediate compound (1H-3).

[0492]

[0493] (In formula (24), Rf1 is represented by the above formula, p representing the average degree of polymerization in Rf1 represents 4.0, and q representing the average degree of polymerization represents 4.0.)

[0494] (Production process of compound (1H))

[0495] In a 100 mL eggplant-shaped flask under a nitrogen atmosphere, 6.5 g (number average molecular weight 1110, 5.9 mmol) of the compound represented by formula (24) as the third intermediate compound (1H-3), 0.4 g (molecular weight 137, 2.9 mmol) of epibromohydrin as a (pseudo) halogenated epoxy compound, and 12 mL of N,N-dimethylformamide (DMF) were added, and stirred at room temperature to prepare a mixed solution. 2.9 g (molecular weight 325, 8.8 mmol) of cesium carbonate was added to the mixed solution, and stirred at 70° C. for 8 hours to react.

[0496] 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 the desiccant was filtered and separated, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain compound (1H) (in the two Rf1 in formula (1H), p representing the average degree of polymerization is 4.0, and q representing the average degree of polymerization is 4.0.) 4.5 g (number average molecular weight 2016).

[0497] The obtained compound (1H) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0498] 1H-NMR(CD3COCD3): δ[ppm]3.36-4.68(28H)

[0499] 19 F-NMR (CD3COCD3): δ [ppm] -55.5~-50.6(16F), -77.8(4F), -80.2(4F), -91.0~-88.4(32F)

[0500] [Example 9]

[0501] In Example 8, in the production process of the first intermediate compound (1H-1), HOCH2CF2O (CF2CF2O) is replaced with p (CF2O) q CF2CH2OH (where p, which indicates the average degree of polymerization, is 4.0, and q, which indicates the average degree of polymerization, is 4.0.) was used, while HOCH2CF2O (CF2CF2O) was used. p (CF2O) q 20 g of the compound represented by CF2CH2OH (wherein p represents the average degree of polymerization is 6.3, and q represents the average degree of polymerization is 0) (number average molecular weight 909, molecular weight distribution 1.1), and in the manufacturing process of the third intermediate compound (1H-3), instead of the compound (H-1) represented by the above formula (23), 2.1 g (molecular weight 146, 14.1 mmol) of the compound (I-1) represented by the following formula (25) as an alcohol compound was used to synthesize the third intermediate compound (1I-3). Except for this, the same operation as in Example 8 was carried out to obtain 4.6 g (number average molecular weight 2050) of the compound (1I) (among the two Rf1 in the formula (1I), p represents the average degree of polymerization is 6.3, and q represents the average degree of polymerization is 0).

[0502]

[0503] The obtained compound (1I) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0504] 1 H-NMR(CD3COCD3): δ[ppm]1.50-1.89(2H), 3.46-4.59(30H)

[0505] 19 F-NMR (CD3COCD3): δ [ppm] -78.6 (4F), -81.2 (4F), -90.1~-88.4 (50.4F)

[0506] [Example 10]

[0507] In the production process of the first intermediate compound (1H-1) in Example 8, HOCH2CF2O (CF2CF2O) is replaced by p (CF2O) q CF2CH2OH (where p, which represents the average degree of polymerization, is 4.0, and q, which represents the average degree of polymerization, is 4.0.) was used, while HOCH2CF2CF2O (CF2CF2CF2O) was used. r 20 g of the compound (number average molecular weight 909, molecular weight distribution 1.1) represented by CF2CF2CH2OH (where r representing the average degree of polymerization is 3.8) was prepared, and in the manufacturing process of the third intermediate compound (1H-3), 4.1 g (molecular weight 288, 14.1 mmol) of the compound (J-1) represented by the following formula (26) as an alcohol compound was used instead of the compound (H-1) represented by the above formula (23) to synthesize the third intermediate compound (1J-3). Except for this, the same operation as in Example 8 was carried out to obtain 4.8 g (number average molecular weight 2078) of the compound (1J) (among the two Rf2 in the formula (1J), r representing the average degree of polymerization is 3.8).

[0508]

[0509] (In formula (26), THP represents tetrahydropyranyl.)

[0510] The compound (J-1) represented by formula (26) is prepared by the method shown below. The hydroxyl group of ethyl 3-hydroxypropionate is protected using 3,4-dihydro-2H-pyran, and the (2-bromoethoxy)tetrahydro-2H-pyran represented by the above formula (14) is reacted with the α position of the ester group of the obtained compound to construct a trisubstituted carbon atom. Then, the ester group of the compound having the trisubstituted carbon atom is reduced. Thus, the compound (J-1) represented by formula (26) is obtained.

[0511] The obtained compound (1J) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0512] 1 H-NMR(CD3COCD3): δ[ppm]1.48-1.84(6H), 3.51-4.50(30H)

[0513] 19F-NMR (CD3COCD3): δ [ppm] -84.0~-83.0(30.4F), -86.3(8F), -124.0(8F), -130.0~-128.8(15.2F)

[0514] [Example 11]

[0515] In the manufacturing process of the third intermediate compound (1J-3) in Example 10, 4.3 g (molecular weight 302, 14.2 mmol) of the compound (K-1) represented by the following formula (27) synthesized as an alcohol compound by the following method was used instead of the compound (J-1) represented by the above formula (26). Except for this, the same operation as in Example 10 was performed to obtain 4.9 g (number average molecular weight 2106) of compound (1K) (in the two Rf2 in formula (1K), r representing the average degree of polymerization is 3.8).

[0516]

[0517] (In formula (27), THP represents tetrahydropyranyl.)

[0518] The compound (K-1) represented by formula (27) was prepared by the method shown below. The hydroxyl group of ethyl 3-hydroxypropionate was protected using 3,4-dihydro-2H-pyran, and the (3-bromopropoxy)tetrahydro-2H-pyran represented by the above formula (16) was reacted with the α position of the ester group of the obtained compound to construct a trisubstituted carbon atom. Then, the ester group of the compound having the trisubstituted carbon atom was reduced. Thus, the compound (K-1) represented by formula (27) was obtained.

[0519] The obtained compound (1K) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0520] 1 H-NMR (CD3COCD3): δ [ppm] 1.36-1.80 (10H), 3.43-4.50 (30H)

[0521] 19 F-NMR (CD3COCD3): δ [ppm] -84.3~-83.0(30.4F), -86.4(8F), -124.2(8F), -130.1~-128.8(15.2F)

[0522] [Example 12]

[0523] In the manufacturing process of the third intermediate compound (1I-3) in Example 9, 4.3 g (molecular weight 302, 14.2 mmol) of the compound (L-1) represented by the following formula (28) synthesized as an alcohol compound by the following method was used instead of the compound (I-1) represented by the above formula (25). Except for this, the same operation as in Example 9 was performed to obtain 4.8 g (number average molecular weight 2106) of compound (1L) (in the two Rf1 in formula (1L), p representing the average degree of polymerization is 6.3, and q representing the average degree of polymerization is 0).

[0524]

[0525] (In formula (28), THP represents tetrahydropyranyl.)

[0526] The compound (L-1) represented by formula (28) is prepared by the method shown below. The hydroxyl group of ethyl 4-hydroxybutyrate is protected using 3,4-dihydro-2H-pyran, and the (2-bromoethoxy)tetrahydro-2H-pyran represented by the above formula (14) is reacted with the α position of the ester group of the obtained compound to construct a trisubstituted carbon atom. Then, the ester group of the compound having the trisubstituted carbon atom is reduced. Thus, the compound (L-1) represented by formula (28) is obtained.

[0527] The obtained compound (1L) was subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0528] 1 H-NMR (CD3COCD3): δ [ppm] 1.34-1.80 (10H), 3.40-4.52 (30H)

[0529] 19 F-NMR (CD3COCD3): δ[ppm]-78.6(4F), -81.0(4F), -90.1~-88.4(50.4F)

[0530] [Example 13]

[0531] In the manufacturing process of the third intermediate compound (1H-3) in Example 8, 4.3 g (molecular weight 302, 14.2 mmol) of the compound (M-1) represented by the following formula (29) synthesized as an alcohol compound by the following method was used instead of the compound (H-1) represented by the above formula (23). Except for this, the same operation as in Example 8 was performed to obtain 4.9 g (number average molecular weight 2101) of compound (1M) (in the two Rf1s in formula (1M), p representing the average degree of polymerization is 4.0, and q representing the average degree of polymerization is 4.0).

[0532]

[0533] (In formula (29), THP represents tetrahydropyranyl.)

[0534] The compound (M-1) represented by formula (29) was synthesized by the following method. First, (2-bromoethoxy)tetrahydro-2H-pyran represented by the above formula (14) was reacted with the α position of the ester group of ethyl 3-butenoate to construct a trisubstituted carbon atom. Then, the ester group of the compound having a trisubstituted carbon atom was reduced, the generated primary hydroxyl group was protected using 3,4-dihydro-2H-pyran, and finally the carbon-carbon double bond site was hydroborated to obtain the compound (M-1) represented by formula (29).

[0535] The obtained compound (1M) was subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0536] 1 H-NMR (CD3COCD3): δ [ppm] 1.37-1.83 (14H), 3.43-4.50 (26H)

[0537] 19 F-NMR (CD3COCD3): δ [ppm] -55.3~-50.6(16F), -77.7(4F), -80.2(4F), -91.0~-88.3(32F)

[0538] [Example 14]

[0539] In the manufacturing process of the third intermediate compound (1J-3) in Example 10, 4.5 g (molecular weight 316, 14.2 mmol) of the compound (N-1) represented by the following formula (30) synthesized as an alcohol compound by the following method was used instead of the compound (J-1) represented by the above formula (26). Except for this, the same operation as in Example 10 was performed to obtain 5.0 g (number average molecular weight 2134) of compound (1N) (in the two Rf2 in formula (1N), r representing the average degree of polymerization is 3.8).

[0540]

[0541] (In formula (30), THP represents tetrahydropyranyl.)

[0542] The compound (N-1) represented by formula (30) was synthesized by the following method. First, the hydroxyl group of 1,5-dihydroxy-3-pentanone was protected with 3,4-dihydro-2H-pyran, and the ketone group was converted into an unsaturated ester with triethyl phosphonoacetate. Then, the carbon-carbon unsaturated bond and ester group of the obtained compound were reduced to obtain the compound (N-1) represented by formula (30).

[0543] The obtained compound (1N) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0544] 1 H-NMR (CD3COCD3): δ [ppm] 1.32-1.76 (14H), 3.45-4.53 (30H)

[0545] 19 F-NMR (CD3COCD3): δ [ppm] -84.4~-83.1(30.4F), -86.4(8F), -124.2(8F), -130.0~-128.8(15.2F)

[0546] [Example 15]

[0547] In the manufacturing process of the third intermediate compound (1I-3) in Example 9, 4.7 g (molecular weight 330, 14.2 mmol) of the compound (O-1) represented by the following formula (31) synthesized as an alcohol compound by the following method was used instead of the compound (I-1) represented by the above formula (25). Except for this, the same operation as in Example 9 was performed to obtain 5.0 g (number average molecular weight 2162) of compound (1O) (in the two Rf1s in formula (1O), p representing the average degree of polymerization is 6.3, and q representing the average degree of polymerization is 0).

[0548]

[0549] (In formula (31), THP represents tetrahydropyranyl.)

[0550] The compound (O-1) represented by formula (31) was synthesized by the following method. First, the hydroxyl group of 1,6-dihydroxy-3-hexanone was protected with 3,4-dihydro-2H-pyran, and the ketone group was converted into an unsaturated ester with triethyl phosphonoacetate. Then, the carbon-carbon unsaturated bond and ester group of the obtained compound were reduced to obtain the compound (O-1) represented by formula (31).

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

[0552] 1 H-NMR(CD3COCD3): δ[ppm]1.33-1.87(18H), 3.40-4.62(30H)

[0553] 19 F-NMR (CD3COCD3): δ[ppm]-78.5(4F), -81.2(4F), -90.2~-88.3(50.4F)

[0554] [Example 16]

[0555] (Process for producing the first intermediate compound (2A-1))

[0556] In the production process of the intermediate compound (1A-1) in Example 1, HOCH2CF2CF2O (CF2CF2CF2O) was replaced with r CF2CF2CH2OH (where r represents the average degree of polymerization is 3.8.), while HOCH2CF2CF2O (CF2CF2CF2O) is used. r 20 g of the compound (number average molecular weight 610, molecular weight distribution 1.1) represented by CF2CF2CH2OH (where r representing the average degree of polymerization is 2.0) was prepared. Otherwise, the same operations as those up to the production process of the third intermediate compound (1A-3) in Example 1 were carried out to obtain 6.0 g of the first intermediate compound (2A-1) represented by the following formula (32).

[0557]

[0558] (In formula (32), Rf2 is represented by the above formula, and r representing the average degree of polymerization in Rf2 is 2.0.)

[0559] (Process for producing the second intermediate compound (2A-2))

[0560] In a 100 mL eggplant flask under nitrogen atmosphere, add HOCH2CF2CF2O (CF2CF2CF2O) r 10 g of a compound represented by CF2CF2CH2OH (where r in the formula represents the average degree of polymerization is 2.0) (number average molecular weight 610, molecular weight distribution 1.1), 4.9 g of epibromohydrin (molecular weight 136, 36.1 mmol) as a (pseudo) halogenated epoxy compound, and 33 mL of tert-butyl alcohol were stirred at room temperature to prepare a mixed solution. 4.6 g of potassium tert-butylate (molecular weight 112, 41.0 mmol) was added to the mixed solution, and the mixture was stirred at 70°C for 5 hours to react.

[0561] 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 by 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 8.0 g of a compound represented by the following formula (33) as a second intermediate compound (2A-2).

[0562]

[0563] (In formula (33), r representing the average degree of polymerization is 2.0.)

[0564] (Process for producing compound (2A))

[0565] In a 100 mL eggplant flask under a nitrogen atmosphere, 6.0 g (number average molecular weight 856, 7.0 mmol) of the first intermediate compound (2A-1) represented by the above formula (32), 2.5 g (number average molecular weight 722, 3.5 mmol) of the second intermediate compound (2A-2) represented by the above formula (33), and 14 mL of tert-butyl alcohol were added, and stirred at room temperature to prepare a mixed solution. 3.4 g (molecular weight 112, 10.5 mmol) of potassium tert-butylate was added to the mixed solution, and the mixture was stirred at 70° C. for 10 hours to react.

[0566] 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 compound (2A) (in the three Rf2 in formula (2A), r representing the average degree of polymerization is 2.0.) 4.5 g (number average molecular weight 2123).

[0567] The obtained compound (2A) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0568] 1 H-NMR (CD3COCD3): δ [ppm] 3.35~4.41 (46H)

[0569] 19 F-NMR (CD3COCD3): δ [ppm] -84.0~-83.0(30.4F), -86.4(8F), -124.3(8F), -130.0~-129.0(15.2F)

[0570] [Example 17]

[0571] In the manufacturing process of the first intermediate compound (2A-1) in Example 16, 3.9 g (molecular weight 223, 13.0 mmol) of the compound (B-1) represented by the above formula (16) was used instead of the compound (A-2) represented by formula (14). Except for this, the same operation as in Example 16 was performed to obtain 6.1 g (number average molecular weight 2151) of compound (2B) (among the three Rf2 in formula (2B), r representing the average degree of polymerization is 2.0).

[0572] The obtained compound (2B) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0573] 1 H-NMR(CD3COCD3): δ[ppm]1.53-1.83(4H), 3.40~4.36(46H)

[0574] 19 F-NMR (CD3COCD3): δ [ppm] -84.0~-83.1(30.4F), -86.3(8F), -124.3(8F), -130.1~-129.0(15.2F)

[0575] [Example 18]

[0576] In the manufacturing process of the first intermediate compound (2A-1) in Example 16, 5.9 g (molecular weight 172, 34.6 mmol) of the compound (C-1) represented by the above formula (17) was used instead of the compound (A-1) represented by the above formula (12). Except for this, the same operation as in Example 16 was carried out to obtain 6.0 g (number average molecular weight 2151) of compound (2C) (among the three Rf2 in formula (2C), r representing the average degree of polymerization is 2.0).

[0577] The obtained compound (2C) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0578] 1 H-NMR(CD3COCD3): δ[ppm]1.48-1.87(4H), 3.40~4.39(46H)

[0579] 19 F-NMR (CD3COCD3): δ [ppm] -84.0~-83.0(30.4F), -86.4(8F), -124.2(8F), -130.1~-129.0(15.2F)

[0580] [Example 19]

[0581] In the manufacturing process of the first intermediate compound (2A-1) in Example 16, 6.4 g (molecular weight 186, 34.6 mmol) of the compound (D-1) represented by the above formula (18) was used instead of the compound (A-1) represented by the above formula (12). Except for this, the same operation as in Example 16 was performed to obtain 6.2 g (number average molecular weight 2179) of compound (2D) (among the three Rf2 in formula (2D), r representing the average degree of polymerization is 2.0).

[0582] The obtained compound (2D) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0583] 1 H-NMR(CD3COCD3): δ[ppm]1.45-1.87(8H), 3.36~4.50(46H)

[0584] 19F-NMR (CD3COCD3): δ [ppm] -84.0~-83.1(30.4F), -86.3(8F), -124.4(8F), -130.0~-129.0(15.2F)

[0585] [Example 20]

[0586] In the manufacturing process of the first intermediate compound (2A-1) in Example 16, 7.0 g (molecular weight 202, 34.6 mmol) of the compound (E-1) represented by the above formula (19) was used instead of the compound (A-1) represented by the above formula (12). Except for this, the same operation as in Example 16 was performed to obtain 6.4 g (number average molecular weight 2211) of compound (2E) (among the three Rf2 in formula (2E), r representing the average degree of polymerization is 2.0).

[0587] The obtained compound (2E) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0588] 1 H-NMR (CD3COCD3): δ [ppm] 3.30~4.57 (54H)

[0589] 19 F-NMR (CD3COCD3): δ [ppm] -84.2~-83.1(30.4F), -86.4(8F), -124.3(8F), -130.1~-129.0(15.2F)

[0590] [Example 21]

[0591] In the manufacturing process of the first intermediate compound (2A-1) in Example 16, 6.9 g (molecular weight 200, 34.6 mmol) of the compound (F-1) represented by the above formula (20) was used instead of the compound (A-1) represented by the above formula (12). Except for this, the same operation as in Example 16 was performed to obtain 6.3 g (number average molecular weight 2207) of compound (2F) (among the three Rf2 in formula (2F), r representing the average degree of polymerization is 2.0).

[0592] The obtained compound (2F) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0593] 1H-NMR(CD3COCD3): δ[ppm]1.25-1.80(12H), 3.40~4.39(46H)

[0594] 19 F-NMR (CD3COCD3): δ [ppm] -84.0~-83.0(30.4F), -86.3(8F), -124.3(8F), -130.1~-129.1(15.2F)

[0595] [Example 22]

[0596] (Production process of first intermediate compound (2G-1))

[0597] In the production process of the first intermediate compound (2A-1) in Example 16, HOCH2CF2CF2O (CF2CF2CF2O) was replaced with r CF2CF2CH2OH (where r, which represents the average degree of polymerization, is 2.0.), while HOCH2CF2O (CF2CF2O) is used p (CF2O) q 20 g of the compound represented by CF2CH2OH (wherein p representing the average degree of polymerization is 2.4, and q representing the average degree of polymerization is 2.4) (number average molecular weight 614, molecular weight distribution 1.1) was used, and, instead of the compound (A-1) represented by the formula (12), 6.89 g (molecular weight 200, 34.4 mmol) of the compound (F-1) represented by the above formula (20) as an epoxy compound was used, and instead of the compound (A-2) represented by the above formula (14), 3.7 g (molecular weight 223, 16.7 mmol) of the compound (B-1) represented by the above formula (16) was used. Except for this, the same operations as in Example 16 were carried out to produce the first intermediate compound (2G-1).

[0598] (Process for producing the second intermediate compound (2G-2))

[0599] In the production process of the second intermediate compound (2A-2) in Example 16, HOCH2CF2CF2O (CF2CF2CF2O) was replaced with r CF2CF2CH2OH (where r, which represents the average degree of polymerization, is 2.0.), while HOCH2CF2O (CF2CF2O) is used p (CF2O) q10 g of the compound represented by CF2CH2OH (wherein p representing the average polymerization degree is 2.4, and q representing the average polymerization degree is 2.4) (number average molecular weight 614, molecular weight distribution 1.1) was added, and the same operation as in Example 16 was performed to produce a second intermediate compound (2G-2).

[0600] (Production process of compound (2G))

[0601] Using the above-mentioned first intermediate compound (2G-1) and the second intermediate compound (2G-2), the same operation as the manufacturing process of compound (2A) in Example 16 was carried out to obtain compound (2G) (Among the three Rf1 in formula (2G), p representing the average degree of polymerization is 2.4, and q representing the average degree of polymerization is 2.4.) 6.0g (number average molecular weight 2249).

[0602] The obtained compound (2G) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0603] 1 H-NMR(CD3COCD3): δ[ppm]1.36-1.85(16H), 3.35~4.46(46H)

[0604] 19 F-NMR (CD3COCD3): δ [ppm] -55.6~-50.6(14.4F), -77.7(6F), -80.2(6F), -91.0~-88.4(28.8F)

[0605] [Example 23]

[0606] (Process for producing the first intermediate compound (2H-1))

[0607] In the production process of the first intermediate compound (1H-1) in Example 8, HOCH2CF2O (CF2CF2O) is replaced by p (CF2O) q CF2CH2OH (wherein p representing the average degree of polymerization is 4.0, and q representing the average degree of polymerization is 4.0) was used, while HOCH2CF2O (CF2CF2O) was used. p (CF2O) q20 g of the compound represented by CF2CH2OH (wherein p represents the average degree of polymerization and q represents the average degree of polymerization is 2.4) (number average molecular weight 614, molecular weight distribution 1.1) were prepared. Otherwise, the same operations as those up to the production process of the third intermediate compound (1H-3) of Example 8 were carried out to obtain 6.0 g of the first intermediate compound (2H-1) represented by the following formula (34).

[0608]

[0609] (In formula (34), Rf1 is represented by the above formula, p representing the average degree of polymerization in Rf1 represents 2.4, and q representing the average degree of polymerization represents 2.4.)

[0610] (Production process of the second intermediate compound (2H-2))

[0611] The same operation as the production step of the second intermediate compound (2G-2) in Example 22 was carried out to synthesize the second intermediate compound (2H-2).

[0612] (Production process of compound (2H))

[0613] In a 100 mL eggplant-shaped flask under a nitrogen atmosphere, 6.0 g of the first intermediate compound (2H-1) represented by formula (34) (number average molecular weight 819, 7.3 mmol), the second intermediate compound (2H-2), and 15 mL of tert-butanol were added, and stirred at room temperature to prepare a mixed solution. 3.6 g of potassium tert-butoxide (molecular weight 112, 11.0 mmol) was added to the mixed solution, and stirred at 70° C. for 10 hours to react.

[0614] 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 compound (2H) (in the three Rf1s in formula (2H), p representing the average degree of polymerization is 2.4, and q representing the average degree of polymerization is 2.4.) 4.6 g (number average molecular weight 2049).

[0615] The obtained compound (2H) is 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0616] 1 H-NMR (CD3COCD3): δ [ppm] 3.36~4.66 (38H)

[0617] 19 F-NMR (CD3COCD3): δ [ppm] -55.7~-50.6(14.4F), -77.8(6F), -80.1(6F), -91.0~-88.4(28.8F)

[0618] [Example 24]

[0619] (Production process of first intermediate compound (2I-1))

[0620] In the production process of the first intermediate compound (2H-1) in Example 23, HOCH2CF2O (CF2CF2O) was replaced with p (CF2O) q CF2CH2OH (where p, which represents the average degree of polymerization, is 2.4, and q, which represents the average degree of polymerization, is 2.4.) was used, while HOCH2CF2O (CF2CF2O) was used. p (CF2O) q 20 g of the compound (number average molecular weight 618, molecular weight distribution 1.1) represented by CF2CH2OH (wherein p representing the average degree of polymerization is 3.8, and q representing the average degree of polymerization is 0) was used, and 2.7 g (molecular weight 146, 18.3 mmol) of the compound (I-1) represented by the above formula (25) as an alcohol compound was used instead of the compound (H-1) represented by the above formula (23). Except for this, the same operation as in Example 23 was carried out to produce the first intermediate compound (2I-1).

[0621] (Process for producing the second intermediate compound (2I-2))

[0622] In the production process of the second intermediate compound (2A-2) in Example 16, HOCH2CF2CF2O (CF2CF2CF2O) was replaced with r CF2CF2CH2OH (where r, which represents the average degree of polymerization, is 2.0.), while HOCH2CF2O (CF2CF2O) is used p (CF2O) q 10 g of the compound represented by CF2CH2OH (wherein p representing the average polymerization degree is 3.8, and q representing the average polymerization degree is 0) (number average molecular weight 618, molecular weight distribution 1.1) was added, and the same operation as in Example 16 was performed to produce a second intermediate compound (2I-2).

[0623] (Production process of compound (2I))

[0624] Using the above-mentioned first intermediate compound (2I-1) and the second intermediate compound (2I-2), the same operation as the manufacturing process of compound (2H) in Example 23 was carried out to obtain compound (2I) (among the three Rf1 in formula (2I), p representing the average degree of polymerization is 3.8, and q representing the average degree of polymerization is 0.) 4.5 g (number average molecular weight 2089).

[0625] The obtained compound (2I) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0626] 1 H-NMR(CD3COCD3): δ[ppm]1.50-1.90(2H), 3.45~4.60(40H)

[0627] 19 F-NMR (CD3COCD3): δ[ppm]-78.6(6F), -81.3(6F), -90.1~-88.6(45.6F)

[0628] [Example 25]

[0629] (Production process of the first intermediate compound (2J-1))

[0630] In the production process of the first intermediate compound (2H-1) in Example 23, HOCH2CF2O (CF2CF2O) was replaced with p (CF2O) q CF2CH2OH (where p, which represents the average degree of polymerization, is 2.4, and q, which represents the average degree of polymerization, is 2.4.) was used, while HOCH2CF2CF2O (CF2CF2CF2O) was used. r 20 g of the compound (number average molecular weight 610, molecular weight distribution 1.1) represented by CF2CF2CH2OH (where r representing the average degree of polymerization is 2.0) was used, and 4.1 g (molecular weight 288, 14.1 mmol) of the compound (J-1) represented by the above formula (26) as an alcohol compound was used instead of the compound (H-1) represented by the above formula (23). Except for this, the same operation as in Example 23 was carried out to produce the first intermediate compound (2J-1).

[0631] (Production process of the second intermediate compound (2J-2))

[0632] The same operation as the production step of the second intermediate compound (2A-2) in Example 16 was carried out to synthesize the second intermediate compound (2J-2).

[0633] (Production process of compound (2J))

[0634] Using the above-mentioned first intermediate compound (2J-1) and the second intermediate compound (2J-2), the same operation as the manufacturing process of compound (2H) in Example 23 was carried out to obtain compound (2J) (among the three Rf2 in formula (2J), r representing the average degree of polymerization is 2.0.) 4.5 g (number average molecular weight 2091).

[0635] The obtained compound (2J) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0636] 1 H-NMR(CD3COCD3): δ[ppm]1.46-1.86(6H), 3.40~4.55(40H)

[0637] 19 F-NMR (CD3COCD3): δ [ppm] -84.0~-83.0(30.4F), -86.2(8F), -124.4(8F), -130.0~-129.0(15.2F)

[0638] [Example 26]

[0639] In the manufacturing process of the first intermediate compound (2J-1) in Example 25, 5.6 g (molecular weight 302, 18.4 mmol) of the compound (K-1) represented by the above formula (27) as an alcohol compound was used instead of the compound (J-1) represented by the above formula (26). Except for this, the same operation as in Example 25 was performed to obtain 4.7 g (number average molecular weight 2119) of compound (2K) (among the three Rf2 in formula (2K), r representing the average degree of polymerization is 2.0).

[0640] The obtained compound (2K) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0641] 1 H-NMR(CD3COCD3): δ[ppm]1.35-1.86(10H), 3.47~4.63(40H)

[0642] 19 F-NMR (CD3COCD3): δ [ppm] -84.0~-83.0(30.4F), -86.2(8F), -124.4(8F), -130.1~-129.0(15.2F)

[0643] [Example 27]

[0644] In the manufacturing process of the first intermediate compound (2I-1) in Example 24, 5.6 g (molecular weight 302, 18.4 mmol) of the compound (L-1) represented by the above formula (28) as an alcohol compound was used instead of the compound (I-1) represented by the above formula (25). Except for this, the same operation as in Example 24 was performed to obtain 4.7 g (number average molecular weight 2145) of compound (2L) (among the three Rf1 in formula (2L), p representing the average degree of polymerization is 3.8, and q representing the average degree of polymerization is 0).

[0645] The obtained compound (2L) was subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0646] 1 H-NMR(CD3COCD3): δ[ppm]1.34-1.80(10H), 3.40~4.52(40H)

[0647] 19 F-NMR (CD3COCD3): δ[ppm]-78.6(6F), -81.2(6F), -90.1~-88.6(45.6F)

[0648] [Example 28]

[0649] In the manufacturing process of the first intermediate compound (2H-1) in Example 23, 5.5 g (molecular weight 302, 18.4 mmol) of the compound (M-1) represented by the above formula (29) as an alcohol compound was used instead of the compound (H-1) represented by the above formula (23). Except for this, the same operations as in Example 23 were performed to obtain 4.8 g (number average molecular weight 2133) of compound (2M) (among the three Rf1 in formula (2M), p representing the average degree of polymerization is 2.4, and q representing the average degree of polymerization is 2.4).

[0650] The obtained compound (2M) was subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0651] 1 H-NMR(CD3COCD3): δ[ppm]1.40-1.86(14H), 3.40~4.60(36H)

[0652] 19F-NMR (CD3COCD3): δ [ppm] -55.7~-50.7(14.4F), -77.7(6F), -80.1(6F), -91.0~-88.4(28.8F)

[0653] [Example 29]

[0654] In the manufacturing process of the first intermediate compound (2J-1) in Example 25, 5.8 g (molecular weight 316, 18.4 mmol) of the compound (N-1) represented by the above formula (30) as an alcohol compound was used instead of the compound (J-1) represented by the above formula (26). Except for this, the same operation as in Example 25 was performed to obtain 4.9 g (number average molecular weight 2147) of compound (2N) (among the three Rf2 in formula (2N), r representing the average degree of polymerization is 2.0).

[0655] The obtained compound (2N) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0656] 1 H-NMR(CD3COCD3): δ[ppm]1.35-1.80(14H), 3.40~4.66(40H)

[0657] 19 F-NMR (CD3COCD3): δ [ppm] -84.0~-83.0(30.4F), -86.1(8F), -124.3(8F), -130.0~-129.0(15.2F)

[0658] [Example 30]

[0659] In the manufacturing process of the first intermediate compound (2I-1) in Example 24, 6.0 g (molecular weight 330, 18.4 mmol) of the compound (O-1) represented by the above formula (31) as an alcohol compound was used instead of the compound (I-1) represented by the above formula (25). Except for this, the same operation as in Example 24 was performed to obtain 5.0 g (number average molecular weight 2201) of compound (2O) (among the three Rf1 in formula (2O), p representing the average degree of polymerization is 3.8, and q representing the average degree of polymerization is 0).

[0660] The obtained compound (2O) is subjected to 1 H-NMR and 19 The structure was identified based on the following results from F-NMR measurement.

[0661] 1H-NMR(CD3COCD3): δ[ppm]1.35-1.87(18H), 3.42~4.68(40H)

[0662] 19 F-NMR (CD3COCD3): δ[ppm]-78.5(6F), -81.0(6F), -90.1~-88.6(45.6F)

[0663] The compounds (1A) to (1O) and (2A) to (2O) of Examples 1 to 30 obtained in this manner were respectively substituted into the formula (1), and the values ​​of z and R at that time were changed to 1 , R 2 , R 3 , R 4 The structures are shown in Tables 1 to 5.

[0664] Regarding the items shown in Tables 1 to 5, from the left, "z" is the value of z shown in formula (1), "R 1 " is R as the branched terminal group of formula (1) 1 , R on the left 1 Indicates the actual branched end group, the R on the right 1 R is represented by formula (2-1) or formula (2-2) 1 In the case of the structure, "R 2 " represents R of formula (1) represented by formula (7-1) or formula (7-2) 2 In the case of the structure, "R 3 ” represents the R of formula (1) 3 As shown in formula (4), “R 4 ” represents the R of formula (1) 4 structure.

[0665] In the compounds (1A) to (1O) and (2A) to (2O) of Examples 1 to 30, for R represented by formula (4), 3 , h=1, i=1.

[0666] Table 1

[0667]

[0668] Table 2

[0669]

[0670] Table 3

[0671]

[0672] Table 4

[0673]

[0674] Table 5

[0675]

[0676] [Comparative Example 1]

[0677] By the method described in Patent Document 1, a compound (3A) represented by the following formula (35) was synthesized.

[0678]

[0679] (In formula (35), Rf2 is represented by the above formula, and r representing the average degree of polymerization in Rf2 is 3.8.)

[0680] [Comparative Example 2]

[0681] By the method described in Patent Document 2, a compound (3B) represented by the following formula (36) was synthesized.

[0682]

[0683] (In formula (36), Rf2 is represented by the above formula, and r representing the average degree of polymerization in Rf2 is 3.8.)

[0684] [Comparative Example 3]

[0685] By the method described in Patent Document 3, a compound (3C) represented by the following formula (37) was synthesized.

[0686]

[0687] (In formula (37), Rf1 is represented by the above formula, p representing the average degree of polymerization in Rf1 represents 3.8, and q representing the average degree of polymerization represents 0.)

[0688] [Comparative Example 4]

[0689] By the method described in Patent Document 4, a compound (3D) represented by the following formula (38) was synthesized.

[0690]

[0691] (In formula (38), Rf1 is represented by the above formula. In the central Rf1, p indicating the average degree of polymerization is 3.8, and q indicating the average degree of polymerization is 0. In the two terminal Rf1s, p indicating the average degree of polymerization is 2.4, and q indicating the average degree of polymerization is 2.4.)

[0692] [Comparative Example 5]

[0693] By the method described in Patent Document 5, a compound (3E) represented by the following formula (39) was synthesized.

[0694]

[0695] (In formula (39), Rf1 is represented by the above formula, p representing the average degree of polymerization in Rf1 represents 4.5, and q representing the average degree of polymerization represents 4.5.)

[0696] [Comparative Example 6]

[0697] By the method described in Patent Document 5, a compound (3F) represented by the following formula (40) was synthesized.

[0698]

[0699] (In formula (40), Rf1 is represented by the above formula, p representing the average degree of polymerization in Rf1 represents 4.5, and q representing the average degree of polymerization represents 4.5.)

[0700] [Comparative Example 7]

[0701] By the method described in Patent Document 6, a compound (3G) represented by the following formula (41) was synthesized.

[0702]

[0703] (In formula (41), Rf1 is represented by the above formula, p representing the average degree of polymerization in Rf1 represents 4.5, and q representing the average degree of polymerization represents 4.5.)

[0704] By the above 1 H-NMR and 19 The number average molecular weight (Mn) of the compounds of Examples 1 to 30 and Comparative Examples 1 to 7 obtained in this manner was determined from the results of F-NMR measurement. The results are shown in Tables 6 and 7. It is estimated that the average molecular weight of the synthesized compound has a deviation of about 1 to 5 depending on the molecular weight distribution of the fluoropolyether used as a raw material of the compound, the difference in the operation when synthesizing the compound, and the like.

[0705] Table 6

[0706]

[0707] Table 7

[0708]

[0709] Next, a lubricant layer forming solution was prepared by the method described below using the compounds obtained in Examples 1 to 30 and Comparative Examples 1 to 7. 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 30 and Comparative Examples 1 to 7.

[0710] "Lubricating layer forming solution"

[0711] The fluorinated ether compounds obtained in Examples 1 to 30 and Comparative Examples 1 to 7 were dissolved in a fluorinated solvent, Batorel (registered trademark) XF (trade name, manufactured by Mitsui Dupont Fluoro Chemical Co., Ltd.), respectively, to form a film with a thickness of 1000 Å to 2000 Å on the protective layer. The solution was diluted with Batler XF in a manner of 100% to prepare a lubricating layer forming solution.

[0712] "Magnetic Recording Media"

[0713] 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.

[0714] 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 30 and Comparative Examples 1 to 7 were applied by dipping, respectively. 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.

[0715] Then, the magnetic recording medium coated with the lubricating layer forming solution was placed in a thermostatic bath at 120° C. and heated for 10 minutes to remove the solvent in the lubricating layer forming solution, thereby forming a lubricating layer on the protective layer to obtain a magnetic recording medium.

[0716] "Film thickness measurement"

[0717] The lubricating layers of the magnetic recording media of Examples 1 to 30 and Comparative Examples 1 to 7 obtained in this manner were measured for the peak height in CF vibration expansion using FT-IR (trade name: Nicolet iS50, manufactured by Thermo Fisher Scientific). Next, the film thickness of the lubricating layer was calculated from the measured value of the peak height in CF vibration expansion of the lubricating layer using the correlation formula obtained by the method described below.

[0718] "Calculation method of correlation"

[0719] A magnetic disk was prepared in which an adhesive layer, a soft magnetic layer, a first base layer, a second base layer, a magnetic layer and a protective layer were sequentially arranged on a substrate having a diameter of 65 mm. (by A lubricating layer is formed with a film thickness of 100 nm and a spacing of 100 nm.

[0720] Then, for each disk with a lubricating layer formed, the film thickness increase compared with the disk surface without a lubricating layer was measured using an ellipsometer, and the film thickness of the lubricating layer was determined. In addition, for each disk with a lubricating layer formed, the peak height in CF vibration expansion was measured using FT-IR.

[0721] Furthermore, a correlation equation between the peak height obtained by FT-IR and the film thickness of the lubricating layer obtained by using an ellipsometer was determined.

[0722] Next, the magnetic recording media of Examples 1 to 30 and Comparative Examples 1 to 7 were subjected to a wear resistance test and a smoothness test by the following methods and evaluated.

[0723] "Abrasion resistance test"

[0724] Using a pin-on-disk friction and wear tester, an alumina ball with a diameter of 2 mm as a contact member was slid on the lubricating layer of the magnetic recording medium at a load of 40 gf and a sliding speed of 0.25 m / sec, and the friction coefficient of the surface of the lubricating layer was measured. Furthermore, the sliding time (friction coefficient increase time) until the friction coefficient of the surface of the lubricating layer increased sharply was measured. The friction coefficient increase time was measured 4 times for each lubricating layer of each magnetic recording medium, and its average value (hours) was set as an index of the wear resistance of the lubricant coating.

[0725] "Evaluation criteria for wear resistance"

[0726] The results of the friction coefficient increase time of the magnetic recording media using the compounds of Examples 1 to 30 and the compounds of Comparative Examples 1 to 7 are shown in Tables 6 and 7. The friction coefficient increase time was evaluated as follows: A larger value of the friction coefficient increase time is understood to indicate a better result.

[0727] A: More than 650 seconds

[0728] B: 550 seconds or more and less than 650 seconds

[0729] C: 450 seconds or more and less than 550 seconds

[0730] D: Less than 450 seconds

[0731] In addition, the time until the friction coefficient increases sharply can be used as an indicator of the wear resistance of the lubricating layer for the reasons shown below. The reason is that the lubricating layer of the magnetic recording medium is worn out due to the use of the magnetic recording medium. If the lubricating layer disappears due to wear, the contact member and the protective layer are in direct contact, and the friction coefficient increases sharply. It can be considered that the time until the friction coefficient increases sharply is also related to the friction test.

[0732] "Smoothness Test"

[0733] As an evaluation index of the smoothness of the lubricating layer surface, touch down power (TDp) was measured. The measurement of TDp was performed as follows using a writing tester (DFH tester).

[0734] The magnetic recording medium to be evaluated was rotated at 5400 rpm, and the magnetic head was arranged at a position 18 mm from the center radius. The heater power of the write element (DFH element) of the magnetic head was slowly increased, and the DFH element was thermally expanded by the heat generated by the heater. Furthermore, the heater power at the moment when the front end of the DFH element protruded due to the thermal expansion of the DFH element came into contact with the lubricating layer of the magnetic recording medium was measured as TDp (unit: mW). The so-called contact between the front end of the DFH element and the lubricating layer of the magnetic recording medium was detected by an acoustic emission (AE) sensor.

[0735] Generally speaking, if the thickness of the lubricating layer is reduced, the TDp required for the surface contact between the DFH element and the lubricating layer becomes larger. On the other hand, it is known that when magnetic recording media having the same average film thickness are compared with each other, the larger the surface unevenness of the lubricating layer, the larger the maximum height of the lubricating layer, and thus the smaller the TDp value.

[0736] “Evaluation Criteria for Smoothness”

[0737] The smoothness of the lubricating layer of the magnetic recording medium using the compounds of Examples 1 to 30 and the compounds of Comparative Examples 1 to 7 was evaluated as follows.

[0738] A: TDp value 51.5mW or more (very small surface unevenness)

[0739] B: TDp value 51.0~51.4mW (small surface unevenness)

[0740] C: TDp value 50.5~50.9mW (large surface unevenness)

[0741] D: TDp value 50.4mW or less (surface unevenness is very large)

[0742] “Comprehensive evaluation”

[0743] Based on the results of the wear resistance test and the smoothness test, comprehensive evaluation was performed according to the following evaluation criteria.

[0744] “Evaluation criteria for comprehensive evaluation”

[0745] A: The evaluations of abrasion resistance and smoothness were all A.

[0746] B: The evaluations of wear resistance and smoothness were A or B, and at least one of them was B.

[0747] C: At least one of the evaluations of wear resistance and smoothness was C, and no D was found.

[0748] D: At least one of the evaluations of wear resistance and smoothness was rated D.

[0749] As shown in Table 6, the evaluations of the wear resistance test and the smoothness test of the magnetic recording media of Examples 1 to 30 were all "A" or "B", and the comprehensive evaluation was "A" or "B". Therefore, it can be confirmed that the wear resistance of the magnetic recording media of Examples 1 to 30 is good, and the smoothness of the magnetic recording media is high.

[0750] This is presumably because the compounds represented by (1A) to (1O) and (2A) to (2O) forming the lubricating layer of the magnetic recording medium in Examples 1 to 30 all satisfy the formula (1).

[0751] In particular, the smoothness test evaluation of the lubricating layer of the magnetic recording media of Examples 1 to 7, 11, 12, 14 to 22, 26, 27, 29, and 30 using compounds (1A) to (1G), (1K), (1L), (1N), (1O), (2A) to (2G), (2K), (2L), (2N), and (2O) was all "A".

[0752] It is believed that in the compound group used in the above examples, since the two primary hydroxyl groups contained in the branched terminal group are arranged at a distance of more than 5 atoms from each other, the two primary hydroxyl groups are not easy to aggregate with each other and are easy to interact with the protective layer independently. Therefore, it is easy to wet and spread evenly on the protective layer, forming a lubricating layer with good coating properties, and obtaining particularly excellent smoothness.

[0753] In addition, the wear resistance test evaluation of the lubricating layer of the magnetic recording media of Examples 3 to 7, 12 to 15, 18 to 22, and 27 to 30 using compounds (1C) to (1G), (1L) to (1O), (2C) to (2G), and (2L) to (2O) was "A".

[0754] In the compound group used in the above-mentioned embodiment, the distance between the perfluoropolyether chain and the two primary hydroxyl groups contained in the branched terminal group is sufficiently far away. Therefore, the two primary hydroxyl groups contained in the branched terminal group are not affected by the large volume of the perfluoropolyether chain. Therefore, the two primary hydroxyl groups contained in the branched terminal group have high mobility and freedom, and have high adsorption to the protective layer. In addition, the lubricating layer of the above-mentioned embodiment has sufficient fluidity and softness due to the high mobility of the two primary hydroxyl groups contained in the branched terminal group. Therefore, even if a part of the lubricating layer is deformed by wear, the fluorinated ether compound in the lubricating layer moves to other positions, and the repairing force to restore to the original position is also high. As a result, it is speculated that particularly excellent wear resistance is obtained.

[0755] In contrast, as shown in Table 7, the evaluations of the wear resistance test and the smoothness test of Comparative Examples 1 to 7 having a lubricating layer formed using any of the compounds (3A) to (3G) were all "C" or "D", which were inferior to those of Examples 1 to 30. This is presumably because the lubricating layers in Comparative Examples 1 to 7 were formed using compounds that did not satisfy Formula (1).

[0756] Specifically, the magnetic recording media of Comparative Examples 1 to 4 have lubricating layers formed using compounds (3A) to (3D). Compounds (3A) to (3D) have a connecting group having a secondary hydroxyl group disposed between two or three perfluoropolyether chains, and terminal groups having a secondary hydroxyl group and a primary hydroxyl group disposed in sequence at both ends of the perfluoropolyether chain.

[0757] The compounds (3A) to (3D) used in the lubricating layers of Comparative Examples 1 to 4 have a linking group having a hydroxyl group arranged between two or three perfluoropolyether chains. Therefore, the center of the chain structure of the compounds (3A) to (3D) is in close contact with the protective layer. However, since the two terminal groups of the compounds (3A) to (3D) contain secondary hydroxyl groups with a low degree of freedom, the adsorption to the protective layer is insufficient, and the perfluoropolyether chains tend to float.

[0758] In addition, for compounds (3B) and (3C), the linking groups disposed between two or three perfluoropolyether chains each have two secondary hydroxyl groups. It is estimated that if the number of secondary hydroxyl groups contained in the linking group is large, the secondary hydroxyl groups hinder each other from binding to the active points on the protective layer. As a result, it is estimated that the polar groups that do not participate in the binding to the active points on the protective layer induce the polar groups between and / or within the molecules to aggregate, and the wear resistance and smoothness become insufficient.

[0759] In addition, compound (3E) has only one perfluoropolyether chain, and terminal groups containing two primary hydroxyl groups are arranged at both ends. The magnetic recording medium of Comparative Example 5 in which a lubricating layer was formed using compound (3E) was "D" in both the wear resistance test and the smoothness test.

[0760] The number of perfluoropolyether chains of compound (3E) is only 1, and a structure containing a polar group is not configured in the center of the chain structure. Therefore, for the lubricating layer of the magnetic recording medium of Comparative Example 5, only the two ends of the molecule of compound (3E) are in close contact with the protective layer, and the central part of the chain structure is far away from the protective layer. As a result, it can be considered that wear resistance and smoothness become insufficient.

[0761] In addition, the magnetic recording media of Comparative Examples 6 and 7 have lubricating layers formed using compounds (3F) and (3G), respectively. For the magnetic recording medium of Comparative Example 6 using compound (3F), both the wear resistance test and the smoothness test were "D", and for the magnetic recording medium of Comparative Example 7 using compound (3G), the wear resistance test was "D" and the smoothness test was "C".

[0762] Compounds (3F) and (3G) both have only one perfluoropolyether chain, and have terminal structures in which a plurality of hydroxyl groups including two primary hydroxyl groups are arranged at both ends.

[0763] Therefore, for the lubricating layer of the magnetic recording medium of Comparative Examples 6 and 7, the central part of the chain structure is far away from the protective layer, similarly to the lubricating layer of the magnetic recording medium of Comparative Example 5. In addition, in addition to the two primary hydroxyl groups with high mobility and adsorption, the two terminal groups of compounds (3F) and (3G) also contain secondary hydroxyl groups with low degree of freedom, 2 of which are contained in compound (3F) and 1 of which are contained in compound (3G). Compound (3F) has 8 hydroxyl groups in the molecule, and compound (3G) has 6 hydroxyl groups in the molecule. Therefore, it is estimated that for the lubricating layer of the magnetic recording medium of Comparative Examples 6 and 7, there are too many hydroxyl groups involved in adsorption, resulting in hydroxyl groups that cannot be adsorbed on the protective layer and are free. As a result, it is inferred that the polar groups between molecules and / or within the molecule are easy to agglomerate with each other, and the wear resistance and smoothness become insufficient.

[0764] Industrial Availability

[0765] 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 having excellent wear resistance and good smoothness even though the thickness is thin.

[0766] Explanation of symbols

[0767] 10···magnetic recording medium, 11···substrate, 12···adhesion layer, 13···soft magnetic layer, 14···first base layer, 15···second base layer, 16···magnetic layer, 17···protective layer, 18···lubricating 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 -CH2-R 2 ) z -CH2-R 4 (1) In formula (1), z is 1 or 2; R 2 is a perfluoropolyether chain; (z+1) R 2 They may be partly or completely the same, or they may be different; R 1 is a branched terminal group having 3 to 35 carbon atoms represented by the following formula (2); R 4 is an organic group having 3 to 35 carbon atoms and having 1 to 3 polar groups, and R 1 Can be the same or different; R 3 is a divalent linking group represented by the following formula (4); when z is 2, two R 3 It can be the same or different; In formula (2), R 5 and R 6 is an organic group containing no secondary hydroxyl group and tertiary hydroxyl group but one primary hydroxyl group, which may be the same or different; x is an integer of 0 to 3; In formula (4), h is an integer of 1 to 3, and i is an integer of 1 to 3.

2. The fluorine-containing ether compound according to claim 1, wherein the formula (2) is any one of the following formulas (2-1) or (2-2), In formula (2-1), a is an integer of 1 to 3, b is an integer of 1 to 4; X 1 is a hydrogen atom or a group represented by formula (3); X 2 is a group represented by formula (3); X 1 With X 2 It can be the same or different; In formula (2-2), c is an integer of 0 to 3, d and e are each independently an integer of 1 to 5; X 3 and X 4 Each independently represents a hydrogen atom or a group represented by formula (3); X 3 With X 4 It can be the same or different; In formula (3), f is an integer of 2 to 5, and g is 1 or 2.

3. The fluorinated ether compound according to claim 1, wherein R in the formula (1) 4 is a group represented by the formula (2).

4. The fluorinated ether compound according to claim 2, wherein R in the formula (1) 1 and R 4 Both are independently represented by the formula (2-1) or formula (2-2).

5. The fluorine-containing ether compound according to any one of claims 1 to 4, wherein in the formula (1), R 1 and R 4 same.

6. The fluorinated ether compound according to claim 1 or 2, wherein R in the formula (1) 4 is any group represented by the following formula (6-1) to formula (6-3); In formula (6-1), y1 is 1 or 2, y2 is an integer from 0 to 3; X 5 is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, an alkynyl group, or a polar group; when y1 is 1, X 5 For polar groups; in X 5 When X is an aromatic hydrocarbon group or an unsaturated heterocyclic group, 5 The atoms in the ring structure are bound to X 5 Adjacent methylene; in X 5 When it is an alkenyl group or an alkynyl group, X 5 The unsaturated carbon atom in the bond is bonded to X 5 adjacent methylene groups; In formula (6-2), y3 is an integer from 1 to 3, y4 is 0 or 1, and y5 is an integer from 0 to 3; X 5 is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, an alkynyl group, or a polar group; when y4 is 0, X 5 For polar groups; in X 5 When X is an aromatic hydrocarbon group or an unsaturated heterocyclic group, 5 The atoms in the ring structure are bound to X 5 Adjacent methylene; in X 5 When it is an alkenyl group or an alkynyl group, X 5 The unsaturated carbon atom in the bond is bonded to X 5 adjacent methylene groups; In formula (6-3), y6 is 0 or 1, y7 is an integer from 1 to 3, and y8 is an integer from 1 to 3; X 5 is an aromatic hydrocarbon group, an unsaturated heterocyclic group, an alkenyl group, an alkynyl group, or a polar group; when y6 is 0, X 5 For polar groups; in X 5 When X is an aromatic hydrocarbon group or an unsaturated heterocyclic group, 5 The atoms in the ring structure are bound to X 5 Adjacent methylene; in X 5 When it is an alkenyl group or an alkynyl group, X 5 The unsaturated carbon atom in the bond is bonded to X 5 Adjacent methylene groups.

7. The fluorinated ether compound according to any one of claims 1 to 4, wherein the (z+1)th R in the formula (1) 2 Each is independently a perfluoropolyether chain represented by the following formula (5), -(CF2) w1 -O-(CF2O) w2 -(CF2CF2O) w3 -(CF2CF2CF2O) w4 -(CF2CF2CF2CF2O) w5 -(CF2) w6 -(5) In formula (5), w2, w3, w4, and w5 represent average polymerization degrees, and each independently represents 0 to 20; wherein, 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 (5).

8. The fluorinated ether compound according to any one of claims 1 to 4, wherein the (z+1)th R in the formula (1) 2 Each independently represents any one selected from the group consisting of perfluoropolyether chains represented by the following formulae (5-1) to (5-4), -CF2-(OCF2CF2) j -(OCF2) k -OCF2-(5-1) In formula (5-1), j and k represent the average degree of polymerization, j represents 1 to 20, and k represents 0 to 20; -CF2CF2-(OCF2CF2CF2) l -OCF2CF2-(5-2) In formula (5-2), l represents the average degree of polymerization, which is 1 to 15; -CF2CF2CF2-(OCF2CF2CF2CF2) m -OCF2CF2CF2-(5-3) In formula (5-3), m represents the average degree of polymerization and is 1 to 10; -(CF2) w7 -O-(CF2CF2CF2O) w8 -(CF2CF2O) w9 -(CF2) w10 -(5-4) In formula (5-4), w8 and w9 represent average polymerization degrees, and each independently represents 1 to 20; w7 and w10 represent average values ​​of the number of CF2, and each independently represents 1 to 2.

9. The fluorinated ether compound according to any one of claims 1 to 4, wherein the (z+1)th R in the formula (1) 2 All the same. 10 . The fluorine-containing ether compound according to claim 1 , 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: The fluorine-containing ether compound according to any one of claims 1 to 4.

12. A magnetic recording medium, characterized in that: A magnetic recording medium having at least a magnetic layer, a protective layer, and a lubricating layer arranged in sequence on a substrate. The lubricating layer comprises the fluorine-containing ether compound according to any one of claims 1 to 4. 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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