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

Abstract

The present application relates to a fluorine-containing ether compound represented by formula (1). R 1 -O-R 2 -CH2-R 3 -CH2-R 4 -R 5 (1) (in the formula, R 3 is a perfluoropolyether chain; R 1 is an alkenyl group having 2 to 8 carbon atoms or an alkynyl group having 3 to 8 carbon atoms; R 2 , R 4 each independently is a divalent linking group containing 1 or more hydroxyl groups; -R 5 is a group represented by the following formula (2).) -O-(CH2) g -N-R 6 R 7 (2) (in the formula, g is an integer of 2 or 3; R 6 and R 7 are the same or different saturated aliphatic groups; R 6 and R 7 may form a ring structure together with the nitrogen atom).

Description

Technical Field

[0001] This invention relates to fluorinated ether compounds, lubricants for magnetic recording media, and magnetic recording media.

[0002] This application claims priority based on Japanese Patent Application No. 2020-139604, filed on August 20, 2020, the contents of which are incorporated herein by reference. Background Technology

[0003] In order to increase the recording density in magnetic recording reproduction devices, magnetic recording media suitable for high recording density have been developed.

[0004] Traditionally, magnetic recording media have consisted of a recording layer formed on a substrate and a protective layer made of carbon or similar materials formed on the recording layer. The protective layer protects the information recorded in the recording layer while improving the smoothness of the magnetic head.

[0005] However, simply applying a protective layer to the recording layer is insufficient to achieve adequate durability of the magnetic recording medium. Therefore, a lubricant is typically applied to the surface of the protective layer to form a lubricating layer.

[0006] As a lubricant used in forming a lubricating layer of a magnetic recording medium, for example, a lubricant containing a compound having polar groups such as hydroxyl or amino groups at the end of a fluorinated polymer having a repeating structure containing CF2 has been proposed.

[0007] For example, Patent Document 1 discloses a fluorinated polyether compound with an amino alcohol group at the molecule's end. Furthermore, Patent Document 2 discloses a fluorinated ether compound with an alkenyl or alkynyl group bonded to one end of the perfluoropolyether chain and a heterocyclic group bonded to the other end. Additionally, Patent Document 3 discloses a fluorinated ether compound with an amino group containing a hydroxyl group at both ends of the molecule. Furthermore, Patent Document 4 discloses a perfluoropolyether liquid lubricant with an amine functional group at at least one end of the chain molecule.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 11-131083

[0011] Patent Document 2: International Publication No. 2019 / 087548

[0012] Patent Document 3: Japanese Patent Application Publication No. 2006-225572

[0013] Patent Document 4: Japanese Patent No. 4099860

[0014] Patent Document 5: Japanese Patent Application Publication No. 62-57418

[0015] Patent Document 6: Japanese Patent Application Publication No. 2019-67468

[0016] Patent Document 7: International Publication No. 2019 / 054148 Summary of the Invention

[0017] The problem that the invention aims to solve

[0018] In magnetic recording playback devices, it is necessary to further reduce the upward movement of the magnetic head. Therefore, the thickness of the lubricating layer in the magnetic recording medium needs to be made thinner.

[0019] However, generally speaking, if the thickness of the lubricating layer is reduced, the coverage of the lubricating layer decreases, and there is a tendency for the wear resistance of the magnetic recording medium to decrease. In addition, the heat resistance of the lubricating layer has been insufficient in the past, and it is necessary to improve the heat resistance.

[0020] The present invention was made in view of the above circumstances, and its object is to provide a fluorinated ether compound suitable as a lubricant for magnetic recording media, said material being able to form a lubricating layer with excellent wear resistance and heat resistance.

[0021] In addition, the object of the present invention is to provide a lubricant for magnetic recording media that contains the fluorinated ether compound of the present invention and can form a lubricating layer with excellent wear resistance and heat resistance.

[0022] Furthermore, the present invention aims to provide a magnetic recording medium having a lubricating layer comprising the fluorinated ether compound of the present invention, which can reduce the thickness of the lubricating layer and has excellent wear resistance and heat resistance.

[0023] Problem-solving methods

[0024] The first aspect of the present invention provides the following fluorinated ether compounds.

[0025] [1] A fluorinated ether compound, characterized by being represented by the following formula (1).

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

[0027] In equation (1), R 3 It is a perfluoropolyether chain; R 1 It is an alkenyl group with 2 to 8 carbon atoms or an alkynyl group with 3 to 8 carbon atoms; R 2 R 4 Each is independently a divalent linker containing one or more hydroxyl groups; -R 5It is the group represented by the following formula (2).

[0028] -O-(CH2) g -NR 6 R 7 (2)

[0029] In equation (2), g is an integer of 2 or 3; R 6 and R 7 They are the same or different saturated aliphatic groups; R 6 and R 7 It can form a ring structure together with nitrogen atoms.

[0030] The compound of the first embodiment of the present invention preferably contains the features described below [2] to

[11] . It is also preferred that two or more of these features are combined.

[0031] [2] According to the fluorinated ether compound described in [1], -R in the above formula (1) 2 - It is represented by the following formula (3).

[0032] -((CH2) a -O) z -[X]-[Y]-(3)

[0033] In equation (3), a represents an integer from 1 to 3, and z represents 0 or 1; [X] is represented by the following equation (X), and [Y] is represented by the following equation (Y). The bonding order of [X] and [Y] can be reversed; however, the sum of c in equation (X) and e in equation (Y) is 1 or 2.

[0034]

[0035] In equation (X), b is an integer from 1 to 3, and c is an integer from 0 to 2.

[0036] In equation (Y), d is an integer from 2 to 3, and e is an integer from 0 to 2.

[0037] [3] According to the fluorinated ether compound described in [1] or [2], -R in the above formula (1) 4 - It is represented by the following formula (4).

[0038]

[0039] In equation (4), f is an integer from 1 to 2.

[0040] [4] The fluorinated ether compound as described in any one of [1] to [3], wherein the above R 2 The hydroxyl groups contained therein are the same as those of the above-mentioned R. 4 The total number of hydroxyl groups contained is 3 or more.

[0041] [5] According to any one of [1] to [4], R in the above formula (2) 6 and R 7 Each is independently a saturated aliphatic group having 1 to 4 carbon atoms, or R 6 and R 7 It forms 5- to 7-membered rings together with nitrogen atoms.

[0042] [6] The fluorinated ether compound as described in any one of [1] to [4], wherein -NR in formula (2) above. 6 R 7 It is dimethylamino or diethylamino.

[0043] [7] The fluorinated ether compound as described in any one of [1] to [4], wherein -NR in formula (2) above 6 R 7 It is any one of the groups selected from pyrrolidinyl, piperidinyl, morpholinyl, and hexamethyleneimine.

[0044] [8] The fluorinated ether compound according to any one of [1] to [7], wherein R in the above formula (1) 1 It is any one of the groups selected from vinyl, allyl, 3-butenyl, 4-pentenyl, and propargyl.

[0045] [9] The fluorinated ether compound according to any one of [1] to [8], wherein the above R 3 It is any one of the following formulas (5) to (7).

[0046] -CF₂O-(CF₂CF₂O) h -(CF2O) i -CF2-(5)

[0047] In equation (5), h and i represent the average degree of polymerization, which range from 0 to 30 respectively. However, h and i are not both 0.

[0048] -CF(CF3)-(OCF(CF3)CF2) j -OCF(CF3)-(6)

[0049] In equation (6), j represents the average degree of polymerization, which ranges from 0.1 to 30.

[0050] -CF2CF2O-(CF2CF2CF2O) k -CF2CF2-(7)

[0051] In equation (7), k represents the average degree of polymerization, ranging from 0.1 to 30.

[0052]

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

[0053]

[11] The fluorinated ether compound as described in [1] is any one of the compounds represented by the above formula (1).

[0054]

[0055] In formula (A), ma and na represent the average degree of polymerization, where ma represents 1 to 30 and na represents 0 to 30.

[0056] In formula (B), mb and nb represent the average degree of polymerization, where mb represents 1 to 30 and nb represents 0 to 30.

[0057] In Equation (E), me represents the average degree of polymerization, and me means 0.1 to 30.

[0058] In formula (F), mf represents the average degree of polymerization, and mf represents 0.1 to 30.

[0059] In equation (I), pi represents the average degree of polymerization, and pi represents 0.1 to 30.

[0060] A second aspect of the present invention provides the following lubricant.

[0061]

[12] A lubricant for magnetic recording media, characterized in that it comprises any one of [1] to

[11] a fluorinated ether compound.

[0062] The third aspect of the present invention provides the following magnetic recording medium.

[0063]

[13] A magnetic recording medium, wherein at least a magnetic layer, a protective layer and a lubricating layer are sequentially disposed on a substrate, characterized in that,

[0064] The lubricating layer comprises any one of the fluorinated ether compounds described in [1] to

[11] .

[0065]

[14] According to the magnetic recording medium of

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

[0066] Invention Effects

[0067] The fluorinated ether compound of the present invention is the compound represented by the above formula (1), and is therefore suitable as a material for a lubricant for magnetic recording media.

[0068] Since the lubricant for magnetic recording media of the present invention contains the fluorinated ether compound of the present invention, a lubricating layer with excellent wear resistance and heat resistance can be formed.

[0069] The magnetic recording medium of the present invention, having a lubricating layer with excellent wear resistance and heat resistance, can have a thinner lubricating layer, resulting in excellent reliability and durability.

[0070] Brief description of the attached figures

[0071] Figure 1 This is a schematic cross-sectional view showing a preferred embodiment of the magnetic recording medium of the present invention. Detailed Implementation

[0072] In order to solve the above problems, the inventors have repeatedly conducted in-depth research as shown below.

[0073] The results showed that compounds with alkenyl or alkynyl groups at the ends of the perfluoropolyether chains could form a lubricating layer with excellent wear resistance. However, the heat resistance of the lubricating layer formed using these compounds was insufficient. This is presumably because compounds with alkenyl or alkynyl groups are easily oxidized under heat treatment conditions. More specifically, when the alkenyl and / or alkynyl groups in the lubricating layer are oxidized under heat treatment conditions, they generate oxidation decomposition products. These oxidation decomposition products cannot remain on the high-speed rotating magnetic recording media within a hard disk drive. Therefore, it can be inferred that by subjecting the magnetic recording media to high-speed rotation, the coating of the lubricating layer decreases, and the wear resistance of the magnetic recording media deteriorates.

[0074] Therefore, in order to suppress the thermal decomposition of alkenyl or alkynyl groups contained in fluorinated ether compounds, the inventors have conducted repeated studies.

[0075] The results showed that any fluorinated ether compound with an alkenyl or alkynyl group at the first end of the perfluoropolyether chain and a tertiary amine group linked to two or three methylene groups is suitable. Subsequently, it was confirmed that in such fluorinated ether compounds, the tertiary amine inhibits the thermal decomposition of the alkenyl or alkynyl groups, thus resulting in excellent heat resistance. Furthermore, it was confirmed that a lubricating layer containing this fluorinated ether compound exhibits excellent wear resistance, leading to the conception of this invention.

[0076] The following provides a detailed description of preferred examples of the fluorinated ether compound, the lubricant for magnetic recording media (hereinafter sometimes simply referred to as "lubricant"), and the magnetic recording media of the present invention. It should be noted that the present invention is not limited to the embodiments shown below. For example, the present invention is not limited to the examples below; without departing from the spirit of the invention, additions, omissions, substitutions, and changes can be made to the numbers, quantities, ratios, compositions, types, positions, materials, and structures.

[0077] [Fluoroether compounds]

[0078] The fluorinated ether compound in this embodiment is represented by the following formula (1).

[0079] R 1 -OR 2 -CH2-R 3 -CH2-R 4 -R 5 (1)

[0080] In equation (1), R 3 It is a perfluoropolyether chain; R 1 It is an alkenyl group with 2 to 8 carbon atoms or an alkynyl group with 3 to 8 carbon atoms; R 2 R 4 Each is independently a divalent linker containing one or more hydroxyl groups; -R 5 It is the group represented by the following formula (2).

[0081] -O-(CH2) g -NR 6 R 7 (2)

[0082] In equation (2), g is an integer of 2 or 3; R 6 and R 7 They are the same or different saturated aliphatic groups; R 6 and R 7 It can form a ring structure together with nitrogen atoms.

[0083] (R 1 (representing alkenyl or ynyl groups)

[0084] In the fluorinated ether compound represented by formula (1) above, R 1 It is an alkenyl group having 2 to 8 carbon atoms, or an alkynyl group having 3 to 8 carbon atoms. In the fluorinated ether compound of this embodiment, R 1 alkenyl or ynyl groups, and R 2 The hydroxyl group (-OH) in the compound exhibits good interaction with the protective layer in the lubricating layer containing it. In the fluorinated ether compound of this embodiment, as R... 1 The alkenyl group with 2 to 8 carbon atoms or the alkynyl group with 3 to 8 carbon atoms can be appropriately selected based on the required performance of the lubricant containing fluorinated ether compounds.

[0085] In R 1 In the case of an alkenyl group having 2 to 8 carbon atoms, R 1 It is a group having one carbon-carbon double bond. In R 1 In the case of an alkenyl group, if the alkenyl group has 8 or fewer carbon atoms, then regardless of the alkenyl group's structure, R 1 The double bond it possesses and R 2The distances of the hydroxyl groups become appropriate. Thus, the fluorinated ether compound represented by formula (1) exhibits good interaction with the protective layer in the lubricating layer containing it.

[0086] As R 1 The alkenyl group having 2 to 8 carbon atoms is not particularly limited, and examples include vinyl, allyl, crotonyl, butenyl, β-methylallyl, methylbutenyl, pentenyl, hexenyl, heptenyl, and octenyl. Among these, an alkenyl group having 2 to 5 carbon atoms is preferred to obtain a lubricating layer exhibiting good affinity with the protective layer of the magnetic recording medium. Specifically, vinyl, allyl, 3-butenyl, and 4-pentenyl are preferred, with allyl and 3-butenyl being particularly preferred. In R 1 In the case of an alkenyl group having 3 or more carbon atoms, in order to become a fluorinated ether compound that exhibits better interaction with the protective layer of the magnetic recording medium, it is preferable to have a double bond at the very end of the fluorinated ether compound.

[0087] R 1 When R is an alkynyl group with 3 to 8 carbon atoms, 1 It is a group having one carbon-carbon triple bond. In R 1 In the case of an alkynyl group, if the number of carbon atoms in the alkynyl group is 8 or less, then regardless of the structure of the alkynyl group, R 1 The triple bond it possesses and R 2 The distances of the hydroxyl groups are all appropriate. Thus, the fluorinated ether compound represented by formula (1) exhibits good interaction with the protective layer in the lubricating layer containing it.

[0088] As R 1 The alkynyl group having 3 to 8 carbon atoms is not particularly limited, and examples include 1-propynyl, propynyl, butynyl, methylbutynyl, penynyl, methylpentynyl, hexynyl, methylhexynyl, heptynyl, and octyynyl. Among these, an alkynyl group having 3 to 5 carbon atoms is preferred to obtain a lubricating layer exhibiting good affinity with the protective layer of the magnetic recording medium. Specifically, 1-propynyl, propynyl, butynyl, and penynyl are preferred, with propynyl being particularly preferred. Alternatively, the alkynyl group can also be in the form of containing an alkenyl group in the molecule, such as vinylpentynyl. In R 1 In the case of an alkynyl group having 3 or more carbon atoms, in order to obtain a lubricating layer that exhibits better interaction with the protective layer of the magnetic recording medium, it is preferable to have a triple bond at the very end of the fluorinated ether compound.

[0089] (R 2 (representing a divalent linker)

[0090] R in equation (1) 2 It is a divalent linker containing one or more hydroxyl groups. R2 The number of hydroxyl groups contained therein is preferably 1 or 2. Because R 2 Containing one or more hydroxyl groups, the lubricating layer can achieve proper adhesion to the protective layer when a lubricating layer is formed on the protective layer using a lubricant containing the fluorinated ether compound of this embodiment. Therefore, the lubricating layer containing the fluorinated ether compound of this embodiment exhibits good affinity with the protective layer and excellent wear resistance.

[0091] In the above formula (1), -R 2 - Preferably represented by the following formula (3).

[0092] -((CH2) a -O) z -[X]-[Y]-(3)

[0093] In equation (3), a represents an integer from 1 to 3, and z represents 0 or 1; [X] is represented by the following equation (X), and [Y] is represented by the following equation (Y). The bonding order of [X] and [Y] can be reversed; however, the sum of c in equation (X) and e in equation (Y) is 1 or 2.

[0094]

[0095] In equation (X), b is an integer from 1 to 3, and c is an integer from 0 to 2.

[0096] In equation (Y), d is an integer from 2 to 3, and e is an integer from 0 to 2.

[0097] In equation (3), a is an integer from 1 to 3, and z is 0 or 1. If a and z are within this range, then R can be prevented. 1 The alkenyl or ynyl group in the molecule is intramolecularly condensed with the hydroxyl groups possessed by (X) and / or (Y). Therefore, in the presence of the -R group represented by formula (1), 2 -In the lubricating layer of the fluorinated ether compound represented by formula (3), R 1 alkenyl or ynyl groups, and R 2 The hydroxyl groups (-OH) in the formula exhibit good interaction with the protective layer. Therefore, a lubricating layer with high coverage and excellent wear resistance is formed. Furthermore, in formula (3), a is an integer less than 3, and z is 0 or 1, thus preventing R from being affected. 2 The excessively long chain structure in the molecules leads to increased molecular mobility, making it easy to obtain R. 1 alkenyl or ynyl groups, and R 2 The hydroxyl groups in the coating affect the adhesion of the protective layer.

[0098] In equation (3) above, b in equation (X) is an integer from 1 to 3. When b is less than 3, the proportion of carbon atoms in the molecule becomes too high, thereby increasing the hydrophobicity of the molecule. It is not difficult to obtain R. 1alkenyl or ynyl groups, and R 2 The adhesion between the hydroxyl group and the protective layer in formula (X) is ensured. Furthermore, since b in formula (X) is an integer from 1 to 3, the adhesion between the hydroxyl group and the protective layer in formula (X) will not be difficult to obtain due to excessive molecular motion.

[0099] Furthermore, in R 2 If the formula contains one hydroxyl group, and if c in equation (X) is 1 and b is an integer from 1 to 3, then R 2 The hydroxyl groups it contains are not easily affected by surrounding atoms, making it easier to achieve a tight seal with the protective layer. Furthermore, in R... 2 If the number of hydroxyl groups is two, and b is an integer from 1 to 3, then R 2 The appropriate distance between the hydroxyl groups in the molecules (5 to 9 atoms between two hydroxyl groups) can prevent intramolecular aggregation.

[0100] In equation (3) above, d in equation (Y) is an integer from 2 to 3. When d is less than 3, the proportion of carbon atoms in the molecule becomes too high, thereby increasing the hydrophobicity of the molecule. It is not difficult to obtain R. 1 alkenyl or ynyl groups, and R 2 The adhesion between the hydroxyl groups in formula (Y) and the protective layer. In addition, since d in formula (Y) is an integer from 2 to 3, the adhesion between the hydroxyl groups in formula (Y) and the protective layer will not be difficult to obtain due to excessive molecular motion.

[0101] Furthermore, in R 2 If the formula contains one hydroxyl group, and e in formula (Y) is 1 and d is an integer from 2 to 3, then R 2 The hydroxyl groups it contains are not easily affected by surrounding atoms, making it easy to achieve a tight seal with the protective layer. Additionally, in R... 2 If the number of hydroxyl groups is two, and d is an integer from 2 to 3, then R 2 The appropriate distance between the hydroxyl groups in the molecules (5 to 9 atoms between two hydroxyl groups) can prevent intramolecular aggregation.

[0102] In equation (3) above, c in equation (X) is an integer from 0 to 2, and e in equation (Y) is an integer from 0 to 2. The sum of c and e is 1 or 2. Since c and e are within this range, therefore in -R 2 -In the case expressed by equation (3), R 2 It has one or two hydroxyl groups. If the sum of c and e is 1 or more, then when a lubricating layer is formed on the protective layer using a lubricant containing a fluorinated ether compound of this embodiment, R can be obtained. 2 The interaction between the hydroxyl groups and the protective layer. When the sum of c and e is 2, R 2 The interaction between the hydroxyl groups and the protective layer becomes more pronounced.

[0103] Furthermore, since the sum of c and e in equation (3) above is less than 2, it will not be affected by R. 2 The presence of too many hydroxyl groups makes the polarity of fluorinated ether compounds excessively high. Therefore, it can suppress the adhesion of fluorinated ether compounds as foreign matter (stains) to the magnetic head.

[0104] (R 4 (representing a divalent linker)

[0105] R in equation (1) 4 It is a divalent linker containing one or more hydroxyl groups. R 4 The number of hydroxyl groups contained therein is preferably 1 or 2. Because R 4 Containing one or more hydroxyl groups, therefore, when a lubricating layer is formed on the protective layer using a lubricant containing a fluorinated ether compound of this embodiment, the lubricating layer can be formed by R... 4 The interaction between the hydroxyl groups and the protective layer allows for proper adhesion between the lubricating layer and the protective layer. Therefore, the lubricating layer containing the fluorinated ether compound of this embodiment exhibits good affinity with the protective layer and excellent wear resistance.

[0106] In the above formula (1), -R 4 - Preferably represented by the following formula (4).

[0107]

[0108] In equation (4), f is an integer from 1 to 2.

[0109] In equation (4), f is an integer from 1 to 2. Therefore, R 4 When expressed by equation (4), R 4 It has one or two hydroxyl groups. Since f is less than 2, it is not affected by R. 4 The excessive presence of hydroxyl groups makes the polarity of fluorinated ether compounds too high. Therefore, it can suppress the adhesion of fluorinated ether compounds as foreign matter (stains) to the magnetic head.

[0110] R in equation (1) 2 R 4 Each is independently a divalent linker containing one or more hydroxyl groups. Therefore, R 2 and R 4 The total number of hydroxyl groups contained is 2 or more. R 2 and R 4 The total number of hydroxyl groups contained is preferably 3 or more, more preferably 3 or 4. In R 2 and R 4 When the total number of hydroxyl groups contained is 3 or 4, the lubricating layer containing the fluorinated ether compound of this embodiment can easily achieve proper adhesion to the protective layer.

[0111] (R 5 (Formula (2) represents a group having a tertiary amine)

[0112] -R in equation (1) 5 It is the group represented by the following formula (2).

[0113] -O-(CH2) g -NR 6 R 7 (2)

[0114] In equation (2), g is an integer of 2 or 3.

[0115] The group represented by formula (2) includes tertiary amines (-NR). 6 R 7 The lone pair of electrons of the nitrogen atom forming the tertiary amine exhibits good interaction with the protective layer in the lubricating layer containing the fluorinated ether compound represented by formula (1), improving the adhesion to the protective layer. Furthermore, the tertiary amine contained in the group represented by formula (2) has the function of capturing free radicals under heat treatment conditions. Therefore, the fluorinated ether compound of this embodiment has excellent heat resistance. In addition, the lubricating layer containing the fluorinated ether compound of this embodiment, which has excellent heat resistance, can maintain an appropriate coverage rate and has good wear resistance.

[0116] R 5 The nitrogen atom of the tertiary amine contained therein interacts with the alkylene group (-(CH2)) in formula (2). g -) bonding. The -O-(CH2) in equation (2) g - is a divalent linking group with an ether bond, and g in formula (2) is an integer of 2 or 3. Therefore, in the fluorinated ether compound represented by formula (1), the nitrogen atom in the tertiary amine is related to R. 4 The distance between the hydroxyl groups (-OH) in the formula is appropriate. Therefore, the fluorinated ether compound represented by formula (1) is not prone to intramolecular aggregation and can be easily configured to extend uniformly along the surface of the protective layer. Therefore, even if the thickness of the lubricant containing the fluorinated ether compound represented by formula (1) is thin, the surface of the protective layer can be coated with a high coverage, and a lubricating layer with excellent wear resistance can be formed.

[0117] In contrast, if g in formula (2) is less than 2, it becomes a fluorinated ether compound that is prone to intramolecular aggregation. As a result, if the thickness of the lubricating layer containing it is reduced, sufficient coverage and adequate wear resistance cannot be obtained. In addition, when g in formula (2) exceeds 3, the alkylene group is too long, thus increasing the mobility of the molecular ends and making it difficult to obtain the tightness of the tertiary amine to the protective layer.

[0118] In addition, in the fluorinated ether compounds represented by formula (1), R4 Through the ether bond (-O-) in formula (2) and the tertiary amine (-NR) 6 R 7 The groups are bonded together, thus the molecular structure has moderate flexibility. Therefore, in a lubricating layer containing a fluorinated ether compound represented by formula (1), the R in the fluorinated ether compound... 4 and tertiary amines (-NR) 6 R 7 The interaction between the protective layer and the lubricating layer becomes excellent. Therefore, the lubricating layer containing fluorinated ether compounds readily adheres to the protective layer, exhibiting excellent adhesion and wear resistance.

[0119] In the fluorinated ether compound represented by formula (1), the structure of the tertiary amine contained in formula (2) can be appropriately selected according to the performance requirements of the lubricant containing the fluorinated ether compound.

[0120] R in equation (2) 6 and R 7 These can be the same or different saturated aliphatic groups. Saturated aliphatic groups can be any of the following: linear, branched, or cyclic. R 6 and R 7 It can form a ring structure together with nitrogen atoms. The tertiary amine contained in formula (2) is preferably a cyclic amine.

[0121] R 5 The tertiary amine it contains is an acyclic amine (R... 6 and R 7 When R does not form a ring structure with nitrogen atoms, 6 and R 7 Preferably, each group is a saturated aliphatic group with 1 to 4 carbon atoms. In this case, by making the tertiary amine (-NR) in formula (2) 6 R 7 It possesses a suitable volume, thus becoming a fluorinated ether compound with suitable steric hindrance and mobility. Therefore, a lubricating layer containing this fluorinated ether compound can prevent R... 5 The intramolecular aggregation caused by the interaction of the lone pairs of electrons from the nitrogen atoms of the contained tertiary amine with the adjacent hydroxyl groups results in good adhesion of the protective layer. As a result, it can be inferred that the coverage of the protective layer can be maintained more appropriately, resulting in a lubricating layer with better wear resistance.

[0122] R 6 and R 7 When each of the groups is an independent saturated aliphatic group having 1 to 4 carbon atoms, examples of saturated aliphatic groups having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl. Among these, saturated aliphatic groups having 1 to 2 carbon atoms are preferred. Specifically, R is preferred.6 and R 7 Each is independently methyl or ethyl, more preferably R 6 and R 7 Same. That is, R 5 When the tertiary amine contained in it is an acyclic amine, -NR in formula (2) 6 R 7 Preferably, the group is selected from dimethylamino, methylethylamino, or diethylamino. For ease of synthesis, dimethylamino or diethylamino is more preferred.

[0123] R 5 The tertiary amine contained therein is an acyclic amine (R 6 and R 7 When it does not form a ring structure with nitrogen atoms, it acts as a tertiary amine (-NR) in formula (2). 6 R 7 Specific examples include: dimethylamino, diethylamino, dipropylamino, diisopropylamino, di-n-butylamino, diisobutylamino, di-sec-butylamino, di-tert-butylamino, ethylmethylamino, n-propylmethylamino, isopropylmethylamino, n-butylmethylamino, isobutylmethylamino, sec-butylmethylamino, tert-butylmethylamino, ethyl-n-propylamino, ethyl isopropylamino, ethyl-n-butylamino, ethyl isobutylamino, sec-butylethylamino, tert-butylethylamino, isopropylpropylamino, n-butylpropylamino, (2-methylamino) N-(1-methylethyl)-1-butylamino, N-sec-butylpropylamino, N-tert-butylpropylamino, N-(1-methylethyl)-1-butylamino, N-isopropyl-2-methyl-1-propylamino, N-(1-methylethyl)-2-butylamino, N-isopropyl-2-methyl-2-propylamino, butyl isobutylamino, butyl sec-butylamino, butyl tert-butylamino, N-(2-methylpropyl)-2-butylamino, N-(1,1-dimethylethyl)-2-methylpropylamino, N-(1,1-dimethylethyl)-2-butylamino, etc.

[0124] In R 5 The tertiary amine contained therein is a cyclic amine (R 6 and R 7 In the case of forming a ring structure together with nitrogen atoms, as a tertiary amine (-NR) in formula (2) 6 R 7 Specific examples include cyclopropylamino (ethyleneimino), aziridine, pyrrolidinyl, piperidinyl, morpholinyl, hexamethyleneimino, heptamethyleneimino, octamethyleneimino, etc.

[0125] In R 5 The tertiary amine contained therein is a cyclic amine (R 6 and R 7In the case of cyclic amines forming a ring structure together with nitrogen atoms, substituents can be present. Specific examples of substituents include alkyl groups having 1 to 3 carbon atoms and containing a polar group. R 5 When the cyclic amine contained therein has substituents containing polar groups, examples of polar groups include hydroxyl, amino, and carboxyl groups, with hydroxyl being preferred. The bonding position of the substituents in the cyclic amine is not particularly limited, and they can bond to any carbon atom constituting the cyclic amine.

[0126] R 6 and R 7 When forming a ring structure with a nitrogen atom, the ring structure may contain heteroatoms other than the nitrogen atom of the tertiary amine. Examples of heteroatoms other than the nitrogen atom of the tertiary amine include oxygen atoms and / or nitrogen atoms.

[0127] R 5 When the tertiary amine contained in it is a cyclic amine, R is preferred. 6 and R 7 It forms a 5- to 7-membered ring with the nitrogen atom. In this case, by making -NR in equation (2) 6 R 7 It possesses a moderate volume, thus becoming a fluorinated ether compound with moderate steric hindrance and mobility. As a result, the lubricating and protective layers containing it exhibit good affinity and excellent wear resistance. Specifically, -NR in formula (2) 6 R 7 Preferably, it is selected from any one of the groups selected from pyrrolidinyl, piperidinyl, morpholinyl, and hexamethyleneimine.

[0128] In contrast, when the fluorinated ether compound represented by formula (1) has, for example, a primary or secondary amine instead of a tertiary amine in formula (2), the primary or secondary amine has less steric hindrance compared to the tertiary amine. Therefore, the lone pair of electrons of the nitrogen atom easily interacts with the adjacent hydroxyl group, which easily causes intramolecular aggregation. As a result, the lubricating layer containing this fluorinated ether compound has a low coverage and insufficient wear resistance.

[0129] Furthermore, when the fluorinated ether compound represented by formula (1) has an unsaturated heterocycle containing a nitrogen atom instead of the tertiary amine in formula (2), sufficient heat resistance cannot be obtained. This is because the unsaturated heterocycle containing a nitrogen atom undergoes thermal decomposition under heating conditions. Additionally, the unsaturated heterocycle containing a nitrogen atom has a lower mobility compared to the tertiary amine. Therefore, in a lubricating layer containing this fluorinated ether compound, the lone pairs of electrons in the lubricating layer have difficulty approaching the protective layer, making it difficult to achieve a tight seal with the protective layer. Consequently, wear resistance becomes insufficient.

[0130] (R 3 (representing the PFPE chain)

[0131] In the fluorinated ether compound represented by formula (1), R 3 The term refers to a perfluoropolyether chain (hereinafter, sometimes abbreviated as "PFPE chain"). When a lubricant containing a fluorinated ether compound of this embodiment is applied to a protective layer to form a lubricating layer, the PFPE chain coats the surface of the protective layer, imparting lubricity to the lubricating layer and reducing the friction between the magnetic head and the protective layer.

[0132] The PFPE chain is appropriately selected based on the required properties of the lubricant containing fluorinated ether compounds. Examples of PFPE chains include: perfluoromethylene oxide polymers, perfluoroethylene oxide polymers, perfluoropropylene oxide polymers, perfluoroisopropylene oxide polymers, and PFPE chains composed of copolymers of the monomers constituting these polymers.

[0133] The PFPE chain can also be represented by the following formula (Rf), for example, a polymer or copolymer derived from a perfluoroepoxide.

[0134] -(CF2) w1 O(CF2O) w2 (CF2CF2O) w3 (CF2CF2CF2O) w4 (CF2CF2CF2CF2O) w5 (CF2) w6 -(Rf)

[0135] In equation (Rf), w2, w3, w4, and w5 represent the average degree of polymerization, each independently representing 0 to 30; however, w2, w3, w4, and w5 cannot all be 0 at the same time; w1 and w6 represent the average number of -CF2-, each independently representing 1 to 3; there is no particular restriction on the order of repeating units in equation (Rf).

[0136] In formula (Rf), w2, w3, w4, and w5 represent the average degree of polymerization, each independently representing 0 to 30, preferably 0 to 20, and more preferably 0 to 15.

[0137] In formula (Rf), w1 and w6 are average values ​​representing the quantity of -CF2-, each independently representing 1 to 3. In the polymer represented by formula (Rf), w1 and w6 are determined based on the structure of the repeating units arranged at the ends of the chain structure.

[0138] In equation (Rf), (CF2O), (CF2CF2O), (CF2CF2CF2O), and (CF2CF2CF2CF2O) are repeating units. There is no particular restriction on the order of the repeating units in equation (Rf). Furthermore, there is no particular restriction on the number of different types of repeating units in equation (Rf).

[0139] R in equation (1) 3 Preferably, it is a PFPE chain represented by, for example, the following formula (Rf-1).

[0140] -(CF2) w7 O-(CF2CF2O) w8 -(CF2CF2CF2O) w9 -(CF2) w10 -(Rf-1)

[0141] In equation (Rf-1), w8 and w9 represent the average degree of polymerization, each independently representing 0.1 to 30; w7 and w10 represent the average amount of -CF2-, each independently representing 1 to 2.

[0142] The order of (CF2CF2O) and (CF2CF2CF2O) as repeating units in formula (Rf-1) is not particularly limited. Formula (Rf-1) may include any of the following: random copolymers, block copolymers, and alternating copolymers composed of monomer units (CF2CF2O) and (CF2CF2CF2O). In formula (Rf-1), w8 and w9, which represent the average degree of polymerization, are each independently represented as 0.1 to 30, preferably 0.1 to 20, and more preferably 1 to 15. w7 and w10 in formula (Rf-1) are average values ​​representing the amount of -CF2-, and are each independently represented as 1 to 2. w7 and w10 in the polymer represented by formula (Rf-1) are determined according to the structure of the repeating units disposed at the ends of the chain structure, etc.

[0143] R in equation (1) 3 Preferably, it is a group represented by any one of the following formulas (5) to (7). In R 3 When any one of formulas (5) to (7) is used, fluorinated ether compounds are readily synthesized. In R 3 In the case of formula (5) or (7), the raw materials are readily available, and therefore are preferred.

[0144] Additionally, in R 3 In the case of any of formulas (5) to (7), the ratio of the number of oxygen atoms (the number of ether bonds (-O-)) to the number of carbon atoms in the perfluoropolyether chain is appropriate. Therefore, it becomes a fluorinated ether compound with moderate hardness. Therefore, the fluorinated ether compound coated on the protective layer does not easily agglomerate on the protective layer, and a thinner lubricating layer can be formed with sufficient coverage. Furthermore, in R... 3 In the case of any one of formulas (5) to (7), it becomes a fluorinated ether compound that can produce a lubricating layer with good wear resistance.

[0145] -CF₂O-(CF₂CF₂O) h -(CF2O)i -CF2-(5)

[0146] In equation (5), h and i represent the average degree of polymerization, which range from 0 to 30 respectively; however, h and i are not both 0.

[0147] In equation (5), the order of (CF2-CF2-O) and (CF2-O) as repeating units is not particularly restricted. In equation (5), the quantity h of (CF2-CF2-O) and the quantity i of (CF2-O) can be the same or different. However, h and i cannot both be 0. Equation (5) can also include any one of random copolymers, block copolymers, and alternating copolymers composed of monomer units (CF2-CF2-O) and (CF2-O).

[0148] In formula (5), h, representing the average degree of polymerization, is 0 to 30, preferably 1 to 20, and further preferably 3 to 10 in order to make it a fluorinated ether compound that easily wets and spreads on the protective layer and easily obtains a lubricating layer with a uniform film thickness. For example, h is also preferably 4 to 8 or 5 to 7. In formula (5), i, representing the average degree of polymerization, is 0 to 30, preferably 1 to 20, and further preferably 3 to 10 in order to make it a fluorinated ether compound that easily wets and spreads on the protective layer and easily obtains a lubricating layer with a uniform film thickness. For example, i is also preferably 4 to 8 or 5 to 7.

[0149] -CF(CF3)-(OCF(CF3)CF2) j -OCF(CF3)-(6)

[0150] In equation (6), j represents the average degree of polymerization, which ranges from 0.1 to 30.

[0151] In formula (6), j, representing the average degree of polymerization, is 0.1 to 30, preferably 1 to 30, more preferably 2 to 20, and even more preferably 3 to 10 in order to make it a fluorinated ether compound that can easily wet and spread on the protective layer and easily obtain a lubricating layer with a uniform film thickness. For example, j is also preferably 4 to 8 or 5 to 7.

[0152] -CF2CF2O-(CF2CF2CF2O) k -CF2CF2-(7)

[0153] In equation (7), k represents the average degree of polymerization, ranging from 0.1 to 30.

[0154] In formula (7), k, representing the average degree of polymerization, is 0.1 to 30, preferably 1 to 30, more preferably 2 to 20, and even more preferably 3 to 10 in order to make it a fluorinated ether compound that can easily wet and spread on the protective layer and easily obtain a lubricating layer with a uniform film thickness. For example, the above-mentioned k is also preferably 4 to 8 or 5 to 7.

[0155] If h, i, j, and k, which represent the average degree of polymerization in equations (5) to (7), are less than 30, the viscosity of the fluorinated ether compound will not become too high, and the lubricant containing it is easy to apply, which is preferred.

[0156] Here, the reasons for the excellent heat resistance and wear resistance of the lubricating layer containing the fluorinated ether compound of this embodiment will be explained.

[0157] In the fluorinated ether compound represented by formula (1), R 5 The tertiary amine it contains inhibits R 1 The thermal decomposition of the alkenyl or alkynyl groups present. Specifically, the R group in the fluorinated ether compound contained in the lubricating layer. 5 The tertiary amine contained therein, under heat treatment conditions, captures free radicals generated by oxygen in the atmosphere, oxygen present in the lubricating layer, and / or the protective layer. As a result, the oxidative decomposition reaction caused by alkenyl or alkynyl free radicals contained in the fluorinated ether compound is suppressed. Therefore, the lubricating layer containing the fluorinated ether compound represented by formula (1) has good heat resistance, R 1 The improved wear resistance effect brought about by the presence of alkenyl or alkynyl groups is maintained for a long time.

[0158] The case where the lubricating layer is subjected to heat treatment conditions can be exemplified by, for example, the case where the substrate on which the lubricating layer is formed is heated to a temperature of, for example, 100°C to 180°C for heat treatment in order to improve the adhesion between the lubricating layer and the protective layer, or the case where the substrate on which the lubricating layer is formed is irradiated with ultraviolet (UV) light before or after heat treatment.

[0159] Generally, the alkenyl or alkynyl groups in fluorinated ether compounds are prone to oxidation. Therefore, for example, if a lubricating layer containing a fluorinated ether compound with alkenyl or alkynyl groups but without tertiary amines is subjected to heat treatment conditions, the alkenyl or alkynyl groups will be thermally decomposed to generate oxidative decomposition products.

[0160] It is speculated that the oxidative decomposition products generated by the thermal decomposition of alkenyl or alkynyl groups in fluorinated ether compounds are compounds containing aldehydes or ketones. It is further speculated that these oxidative decomposition products are generated by free radicals produced under heating conditions from atmospheric oxygen, oxygen present in the lubrication layer, and / or the protective layer, which oxidize the α- and / or β-positions of the alkenyl or alkynyl groups in the lubrication layer.

[0161] The oxidative decomposition products generated through thermal decomposition are unstable compounds, and therefore can be considered to promote the oxidative decomposition of alkenyl or alkynyl groups in the lubricating layer, thus accelerating the deterioration of the lubricating layer. As a result, it can be inferred that for lubricating layers containing fluorinated ether compounds with alkenyl or alkynyl groups but without tertiary amines, the wear resistance improvement effect brought about by the alkenyl or alkynyl groups in the lubricating layer will decrease in a short period of time.

[0162] Specifically, the fluorinated ether compound in this embodiment is preferably a compound represented by the following formulas (A) to (I). It should be noted that ma~mh, na~nd, and pi in formulas (A) to (I) are values ​​representing the average degree of polymerization, and therefore are not necessarily integers.

[0163] The compounds represented by formulas (A) to (H) below are all R in formula (1) above. 3 For the PFPE chain represented by equation (5) above, R 4 For example, equation (4) above. R 2 It is the above formula (3).

[0164] In the compound represented by the following formula (A), R in the above formula (1) 1 It is allyl, R 2 In equation (X), z is 0; in equation (Y), b is 1; c is 2; in equation (Y), e is 0; and in equation (2), g is 3. 6 R 7 It is morpholino.

[0165] In the compound represented by formula (B) below, R in formula (1) above... 1 It is allyl, R 2 In equation (X), a is 2 and z is 1; in equation (Y), b is 1 and c is 2; in equation (Y), e is 0; and in equation (2), g is 2. 6 R 7 It is piperidinyl.

[0166] For the compound represented by the following formula (C), R in the above formula (1) 1 It is propargyl, R 2 In equation (X), a is 2 and z is 1; in equation (Y), b is 1 and c is 2; in equation (Y), e is 0; and in equation (2), g is 2. 6 R 7 It is a pyrroleyl group.

[0167]

[0168] In formula (A), ma and na represent the average degree of polymerization, where ma represents 1 to 30 and na represents 0 to 30.

[0169] In formula (B), mb and nb represent the average degree of polymerization, where mb represents 1 to 30 and nb represents 0 to 30.

[0170] In equation (C), mc and nc represent the average degree of polymerization, with mc representing 1 to 30 and nc representing 0 to 30.

[0171] The values ​​of ma, mb, and mc can be, for example, 1–20, 2–15, 3–10, 4–8, 5–7, etc. The values ​​of na, nb, and nc can be, for example, 0–25, 1–20, 2–15, 3–10, 4–8, 5–7, etc.

[0172] In the compound represented by the following formula (D), R in the above formula (1) 1 It is allyl, R 2 In equation (X), a is 2 and z is 1; in equation (Y), b is 1 and c is 2; in equation (Y), e is 0; in equation (2), g is 3; -NR 6 R 7 It is dimethylamino.

[0173] In the compound represented by the following formula (E), R in the above formula (1) 1 It is allyl, R 2 In equation (X), z is 0; in equation (Y), b is 1; c is 2; in equation (2), e is 0; and g is 2. 6 R 7 It is morpholino.

[0174] In the compounds represented by the following formula (F), R in the above formula (1) 1 It is butenyl, R 2 In equation (X), z is 0; in equation (Y), b is 1 and c is 1; in equation (Y), d is 2 and e is 1; in equation (2), g is 2; -NR 6 R 7 It is morpholino.

[0175]

[0176] In equation (D), md and nd represent the average degree of polymerization, with md representing 1 to 30 and nd representing 0 to 30.

[0177] In Equation (E), me represents the average degree of polymerization, and me means 0.1 to 30.

[0178] In formula (F), mf represents the average degree of polymerization, and mf represents 0.1 to 30.

[0179] The values ​​of md can be, for example, 1–20, 2–15, 3–10, 4–8, 5–7, etc. The values ​​of nd can be, for example, 0–25, 1–20, 2–15, 3–10, 4–8, 5–7, etc. The values ​​of me and mf can be, for example, 0.1–25, 0.3–20, 0.5–15, 1–10, 2–8, 3–6, etc.

[0180] In the compound represented by the following formula (G), R in the above formula (1) 1 It is butenyl, R 2 In equation (X), z is 0; in equation (Y), b is 1 and c is 1; in equation (Y), d is 2 and e is 1; in equation (2), g is 2; -NR 6 R 7 It is diethylamino.

[0181] In the compounds represented by the following formula (H), R in the above formula (1) 1 It is pentenyl, R 2 In equation (X), z is 0; in equation (Y), b is 1; c is 2; in equation (2), e is 0; and g is 2. 6 R 7 It is a hexamethyleneimine group.

[0182] In the compounds represented by the following formula (I), R in the above formula (1) 3 Let R represent the PFPE chain as shown in equation (7). 4 For equation (4) above, R 1 It is propargyl, R 2 In equation (X), a is 2 and z is 1; in equation (Y), b is 1 and c is 2; in equation (Y), e is 0; in equation (2), g is 3; -NR 6 R 7 It is a pyrroleyl group.

[0183]

[0184] In formula (G), mg represents the average degree of polymerization, and mg represents 0.1 to 30.

[0185] In formula (H), mh represents the average degree of polymerization, and mh represents 0.1 to 30.

[0186] In equation (I), pi represents the average degree of polymerization, and pi represents 0.1 to 30.

[0187] The above mg, mh, and pi can be, for example, 0.1–25, 0.3–20, 0.5–15, 1–10, 2–8, 3–6, etc.

[0188] When the compound represented by formula (1) is any of the compounds represented by formulas (A) to (I) above, the raw materials are readily available. Furthermore, the compounds represented by formulas (A) to (I) all exhibit excellent heat resistance. Moreover, even in thin layers, the compounds represented by formulas (A) to (I) can form a lubricating layer with even better wear resistance and heat resistance. If the compound represented by formula (1) is any one of the compounds represented by formulas (A), (B), (E), (F), or (I), it is particularly preferable that a lubricating layer with excellent heat resistance can be formed.

[0189] The number-average molecular weight (Mn) of the fluorinated ether compound in this embodiment is preferably in the range of 500 to 10,000, more preferably in the range of 700 to 7,000, and particularly preferably in the range of 1,000 to 3,000. If the number-average molecular weight is 500 or higher, the lubricant containing the fluorinated ether compound of this embodiment is less prone to evaporation, preventing the lubricant from evaporating and transferring to the magnetic head. Furthermore, if the number-average molecular weight is 10,000 or lower, the viscosity of the fluorinated ether compound becomes suitable, and a thin lubricating layer can be easily formed by coating a lubricant containing it. If the number-average molecular weight is 3,000 or lower, a viscosity that is easily handled when applied to a lubricant can be formed, which is therefore more preferable.

[0190] The number-average molecular weight (Mn) of fluorinated ether compounds was determined using AVANCE III 400 manufactured by Bruker BioSpin. 1 H-NMR and 19 The value determined by F-NMR. In NMR (nuclear magnetic resonance) determination, the sample is diluted in solvents such as hexafluorobenzene, d-acetone, and d-tetrahydrofuran, either alone or in mixtures, for determination. 19 The baseline for F-NMR chemical shift is set at -164.7 ppm for the peak of hexafluorobenzene. 1 The baseline for the 1H-NMR chemical shift is set at 2.2 ppm for the acetone peak.

[0191] [Manufacturing Method]

[0192] The method for manufacturing the fluorinated ether compound in this embodiment is not particularly limited, and conventionally known manufacturing methods can be used. For example, the fluorinated ether compound in this embodiment can be manufactured using the manufacturing methods shown below.

[0193] First, prepare R in equation (1). 3 The corresponding perfluoropolyether chains are configured with fluorinated compounds containing hydroxymethyl (-CH2OH) groups at both ends.

[0194] Next, the hydroxyl group of the hydroxymethyl group disposed at one end of the above-mentioned fluorine compound is replaced with the hydroxyl group of formula (1) by R. 1 -OR2 - The group constitutes (reaction 1). Then, the hydroxyl group of the above-mentioned hydroxymethyl group configured at the other end is replaced by -R in formula (1). 4 -R 5 The group that forms it (reaction 2).

[0195] The first and second reactions can be carried out using conventionally known methods, based on R in equation (1). 1 R 2 R 4 R 5 The types of substances should be appropriately determined. Additionally, either reaction 1 or reaction 2 can be performed first.

[0196] The compound represented by formula (1) can be obtained by the above method.

[0197] In this embodiment, for example, when importing R 1 -OR 2 In the first reaction of the group formed by - it is preferable to react the hydroxyl group of the single terminal hydroxymethyl group of the above-mentioned fluorine compound with the group corresponding to R. 1 -OR 2 - The reaction of epoxides.

[0198] In addition, in the second reaction, in order to introduce the -R group into the above-mentioned fluorine compounds... 4 -R 5 The constitutive group preferably has a hydroxyl group at the single terminal hydroxymethyl group of the above-mentioned fluorine compound reacting with a group corresponding to -R. 4 -R 5 The reaction of epoxy compounds.

[0199] For the epoxy compound used in manufacturing the fluorinated ether compound of this embodiment, for example, it can be made to have an R that is similar to that of the manufactured fluorinated ether compound. 1 -OR 2 - indicates the end group or -R 4 -R 5 The alcohol corresponding to the indicated end group is synthesized by reacting it with any of the epoxy-containing compounds selected from epichlorohydrin, epibromohydrin, 2-bromoethyl ethylene oxide, and allyl glycidyl ether. Such epoxy compounds can be synthesized by oxidizing unsaturated bonds or can be purchased commercially available.

[0200] By using a lubricant containing the fluorinated ether compound of this embodiment to form a lubricating layer on the protective layer, the following effects can be obtained.

[0201] In the fluorinated ether compound represented by formula (1), R 1The alkenyl or alkynyl groups in the compound exhibit good interaction with the protective layer. Thus, the lubricating layer containing the fluorinated ether compound represented by formula (1) can maintain an appropriate coverage of the protective layer and exhibit excellent wear resistance.

[0202] Additionally, R 5 The tertiary amine contained therein captures free radicals, thereby inhibiting R 1 The alkenyl or alkynyl groups in the compound undergo thermal decomposition. Consequently, the fluorinated ether compound represented by formula (1) and the lubricating layer using it exhibit good heat resistance. More specifically, R... 5 The tertiary amines contained therein can capture free radicals generated under heat treatment conditions, such as heat treatment performed in the range of 100°C to 180°C. Therefore, the R-induced free radicals... 1 The oxidation reaction of alkenyl or alkynyl groups in R is inhibited. 1 The wear resistance enhancement effect brought about by the alkenyl or alkynyl groups is maintained.

[0203] Furthermore, R is formed 5 The lone pairs of electrons in the nitrogen atoms of the tertiary amine exhibit good interaction with the protective layer, thus forming a lubricating layer with good adhesion to the protective layer. Therefore, an appropriate coverage of the protective layer can be maintained, resulting in a lubricating layer with excellent wear resistance.

[0204] Additionally, R 5 The tertiary amine contained therein possesses moderate steric hindrance and mobility. Therefore, it does not impair the interaction of the protective layer caused by the lone pairs of electrons of the nitrogen atoms forming the tertiary amine, and prevents aggregation caused by interactions with the hydroxyl groups adjacent to the tertiary amine. The result is a lubricating layer with appropriate coverage of the protective layer and excellent wear resistance.

[0205] Due to R in the lubrication layer 3 The PFPE chain indicates that the surface of the protective layer is coated, reducing the friction between the magnetic head and the protective layer. Furthermore, through R... 3 The R represented is connected to the first end of the PFPE chain. 2 The hydroxyl groups are bonded to the protective layer, and the R is connected to the second end of the PFPE chain. 4 The hydroxyl groups are bonded to the protective layer, and the lubricating layer adheres tightly to the protective layer. That is, the fluorinated ether compound represented by formula (1) has more than two hydroxyl groups in appropriate positions in the molecule, thus effectively achieving the interaction between the hydroxyl groups and the protective layer, and coating the surface of the protective layer with a high coverage rate. Therefore, the lubricating layer and the protective layer containing the fluorinated ether compound of this embodiment are firmly bonded, and have excellent wear resistance.

[0206] Lubricant for magnetic recording media

[0207] The lubricant for the magnetic recording medium in this embodiment includes a fluorinated ether compound represented by formula (1).

[0208] For the lubricant of this embodiment, known materials used as lubricants may be mixed as needed, provided that the properties of the fluorinated ether compound represented by formula (1) are not impaired.

[0209] Specific examples of known materials include: FOMBLIN (registered trademark) ZDIAC, FOMBLIN ZDEAL, FOMBLIN AM-2001 (all manufactured by Solvay Solexis), Moresco A20H (manufactured by Moresco), etc. The number-average molecular weight of the known materials used in combination with the lubricant of this embodiment is preferably between 1000 and 10000.

[0210] When the lubricant of this embodiment contains materials 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 this 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) can be 80% by mass or more, or 90% by mass or more. The upper limit of the above content can be arbitrarily selected, for example, it can be 99% by mass, 97% by mass, 95% by mass, etc.

[0211] Since the lubricant of this embodiment contains a fluorinated ether compound represented by formula (1), even with a reduced thickness, the surface of the protective layer can be covered with a high coverage rate, and a lubricating layer with excellent adhesion to the protective layer and excellent wear resistance and heat resistance can be formed.

[0212] [Magnetic recording media]

[0213] In this embodiment, the magnetic recording medium has at least a magnetic layer, a protective layer, and a lubricating layer sequentially disposed on the substrate.

[0214] In the magnetic recording medium of this embodiment, one or more base layers can be provided between the substrate and the magnetic layer as needed. Alternatively, an adhesion layer and / or a soft magnetic layer can be provided between the base layer and the substrate.

[0215] Figure 1 This is a schematic cross-sectional view showing an example of an embodiment of the magnetic recording medium of the present invention.

[0216] In this embodiment, the magnetic recording medium 10 is formed on a substrate 11 with an adhesion layer 12, a soft magnetic layer 13, a first base layer 14, a second base layer 15, a magnetic layer 16, a protective layer 17, and a lubricating layer 18 disposed sequentially.

[0217] "Substrate"

[0218] As substrate 11, for example, a non-magnetic substrate on which a film of NiP or NiP alloy is formed on a substrate made of a metal or alloy material such as Al or Al alloy can be used.

[0219] In addition, as substrate 11, a non-magnetic substrate made of non-metallic materials such as glass, ceramic, silicon, silicon carbide, carbon, and resin can be used, or a non-magnetic substrate on which a film of NiP or NiP alloy is formed on a substrate made of these non-metallic materials can be used.

[0220] "Adhesion layer"

[0221] The adhesion layer 12 prevents corrosion of the substrate 11 that occurs when the substrate 11 is placed in contact with the soft magnetic layer 13 disposed on the adhesion layer 12.

[0222] The material of the adhesion layer 12 can be appropriately selected from Cr, Cr alloy, Ti, Ti alloy, CrTi, NiAl, AlRu alloy, etc. The adhesion layer 12 can be formed, for example, by sputtering.

[0223] "Soft magnetic layer"

[0224] The soft magnetic layer 13 preferably has a structure in which a first soft magnetic film, an intermediate layer made of Ru film and a second soft magnetic film are stacked sequentially. That is, the soft magnetic layer 13 preferably has the following structure: by sandwiching an intermediate layer made of Ru film between the two soft magnetic films, the soft magnetic films above and below the intermediate layer are antiferromagnetically coupled (AFC) together.

[0225] Materials used for the first and second soft magnetic films include, for example, CoZrTa alloys and CoFe alloys.

[0226] In the CoFe alloy used in the first and second soft magnetic films, it is preferable to add any one of Zr, Ta, and Nb. This promotes the amorphization of the first and second soft magnetic films, improves the orientation of the first substrate layer (seed layer), and reduces the lift of the magnetic head.

[0227] The soft magnetic layer 13 can be formed, for example, by sputtering.

[0228] "First basal layer"

[0229] The first base layer 14 is a layer that controls the orientation and crystal size of the second base layer 15 and the magnetic layer 16 disposed thereon.

[0230] Examples of first base layers 14 include: Cr layer, Ta layer, Ru layer, or CrMo alloy layer, CoW alloy layer, CrW alloy layer, CrV alloy layer, CrTi alloy layer, etc.

[0231] The first base layer 14 can be formed, for example, by sputtering.

[0232] "Second basal layer"

[0233] The second substrate layer 15 is a layer controlled to ensure good orientation of the magnetic layer 16. The second substrate layer 15 is preferably a layer made of Ru or a Ru alloy.

[0234] The second base layer 15 can be a single layer or multiple layers. If the second base layer 15 is composed of multiple layers, all layers can be made of the same material, or at least one layer can be made of a different material.

[0235] The second base layer 15 can be formed, for example, by sputtering.

[0236] "Magnetic layer"

[0237] The magnetic layer 16 is composed of a magnetic film with its easy magnetization axis facing vertically or horizontally relative to the substrate surface. The magnetic layer 16 is a layer containing Co and Pt, and to further improve the SNR characteristics, it can also be a layer containing oxides, Cr, B, Cu, Ta, Zr, etc.

[0238] Examples of oxides contained in the magnetic layer 16 include SiO2, SiO, Cr2O3, CoO, Ta2O3, and TiO2.

[0239] The magnetic layer 16 can consist of a single layer or multiple magnetic layers comprising different materials.

[0240] For example, when the magnetic layer 16 is composed of three layers stacked sequentially from bottom to top—a first magnetic layer, a second magnetic layer, and a third magnetic layer—the first magnetic layer is preferably a granular structure made of a material containing Co, Cr, Pt, and further comprising oxides. As the oxides contained in the first magnetic layer, oxides of Cr, Si, Ta, Al, Ti, Mg, Co, etc., are preferred. Among these, TiO2, Cr2O3, and SiO2 are particularly preferred. Furthermore, the first magnetic layer is preferably composed of a composite oxide containing two or more oxides. Among these, Cr2O3-SiO2, Cr2O3-TiO2, and SiO2-TiO2 are particularly preferred.

[0241] The first magnetic layer may contain one or more elements selected from B, Ta, Mo, Cu, Nd, W, Nb, Sm, Tb, Ru, and Re, in addition to Co, Cr, Pt, and oxides. The second magnetic layer may use the same material as the first magnetic layer. The second magnetic layer is preferably of a granular structure.

[0242] The third magnetic layer is preferably a non-granular structure made of a material containing Co, Cr, and Pt but not oxides. In addition to Co, Cr, and Pt, the third magnetic layer may also contain one or more elements selected from B, Ta, Mo, Cu, Nd, W, Nb, Sm, Tb, Ru, Re, and Mn.

[0243] When the magnetic layer 16 is formed of multiple magnetic layers, it is preferable to provide a non-magnetic layer between adjacent magnetic layers. When the magnetic layer 16 is composed of three layers: a first magnetic layer, a second magnetic layer, and a third magnetic layer, it is preferable to provide a non-magnetic layer between the first magnetic layer and the second magnetic layer, and between the second magnetic layer and the third magnetic layer.

[0244] For the non-magnetic layer disposed between adjacent magnetic layers of magnetic layer 16, 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, B, etc.) can be used, for example.

[0245] In the non-magnetic layer disposed between adjacent magnetic layers of magnetic layer 16, an alloy material comprising oxides, metal nitrides, or metal carbides is preferably used. Specifically, as oxides, examples include SiO2, Al2O3, Ta2O5, Cr2O3, MgO, Y2O3, TiO2, etc. As metal nitrides, examples include AlN, Si3N4, TaN, CrN, etc. As metal carbides, examples include TaC, BC, SiC, etc.

[0246] Non-magnetic layers can be formed, for example, by sputtering.

[0247] To achieve higher recording density, the magnetic layer 16 is preferably a perpendicular magnetic recording magnetic layer with its easy magnetization axis oriented perpendicular to the substrate surface. The magnetic layer 16 may also be an in-plane magnetic recording magnetic layer.

[0248] The magnetic layer 16 can be formed by any conventionally known method, such as vapor deposition, ion beam sputtering, or magnetron sputtering. The magnetic layer 16 is typically formed by sputtering.

[0249] "Protective layer"

[0250] The protective layer 17 protects the magnetic layer 16. The protective layer 17 can consist of one layer or multiple layers. Examples of materials that can be used for the protective layer 17 include carbon, nitrogen-containing carbon, and silicon carbide.

[0251] As the protective layer 17, a carbon-based protective layer is preferred, and an amorphous carbon protective layer is particularly preferred. If the protective layer 17 is a carbon-based protective layer, the interaction with the hydroxyl groups contained in the fluorinated ether compound in the lubricating layer 18 is further enhanced, and therefore it is preferred.

[0252] The adhesion between the carbon-based protective layer and the lubricating layer 18 can be controlled by setting the carbon-based protective layer to hydrogenated carbon and / or nitrided carbon and adjusting the hydrogen and / or nitrogen content in the carbon-based protective layer. Preferably, the hydrogen content in the carbon-based protective layer is 3 to 20 atomic percent when measured by hydrogen forward scattering (HFS). Furthermore, preferably, the nitrogen content in the carbon-based protective layer is 4 to 15 atomic percent when measured by X-ray photoelectron spectroscopy (XPS).

[0253] The hydrogen and / or nitrogen contained in the carbon-based protective layer do not need to be uniformly contained throughout the entire carbon-based protective layer. For example, it is preferable to configure the protective layer 17 as a tilted layer with nitrogen on the lubrication layer 18 side and hydrogen on the magnetic layer 16 side. In this case, the adhesion between the magnetic layer 16 and the lubrication layer 18 and the carbon-based protective layer is further improved.

[0254] The thickness of the protective layer 17 can be set to 1 nm to 7 nm. If the thickness of the protective layer 17 is 1 nm or more, the performance of the protective layer 17 can be fully obtained. When the thickness of the protective layer 17 is 7 nm or less, it is preferred from the perspective of thin film production of the protective layer 17.

[0255] The film formation method for the protective layer 17 can be sputtering using a carbon-containing target, CVD (chemical vapor deposition) using hydrocarbon raw materials such as ethylene and toluene, or IBD (ion beam deposition).

[0256] When forming a carbon-based protective layer as protective layer 17, the film can be deposited, for example, by DC magnetron sputtering. In particular, when forming a carbon-based protective layer as protective layer 17, it is preferable to form an amorphous carbon protective layer by plasma CVD. The amorphous carbon protective layer formed by plasma CVD has a uniform surface and low roughness.

[0257] "Lubrication layer"

[0258] The lubricating layer 18 prevents contamination of the magnetic recording medium 10. In addition, the lubricating layer 18 reduces the friction of the magnetic head of the magnetic recording and playback device that slides on the magnetic recording medium 10, thereby improving the durability of the magnetic recording medium 10.

[0259] Lubricating layer 18 Figure 1 As shown, they are formed in contact with each other on the protective layer 17. The lubricating layer 18 contains the aforementioned fluorinated ether compound.

[0260] When the protective layer 17 disposed beneath the lubricating layer 18 is a carbon-based protective layer, the lubricating layer 18 is particularly able to bond with the protective layer 17 with high adhesion. As a result, even if the thickness of the lubricating layer 18 is thin, it is easy to obtain a magnetic recording medium 10 with a high coverage of the surface of the protective layer 17, which can effectively prevent surface contamination of the magnetic recording medium 10.

[0261] The average film thickness of the lubricating layer 18 is preferably... More preferably If the average film thickness of the lubricating layer 18 is 0.5 nm or more, the lubricating layer 18 will not form islands or meshes, but will form a uniform film thickness. Therefore, the surface of the protective layer 17 can be covered with a high coverage rate through the lubricating layer 18. In addition, by making the average film thickness of the lubricating layer 18 2.0 nm or less, the lubricating layer 18 can be sufficiently thinned, and the rise of the magnetic head can be significantly reduced.

[0262] If the surface of the protective layer 17 is not covered by the lubricating layer 18 with a sufficiently high coverage, environmental substances adsorbed on the surface of the magnetic recording medium 10 can penetrate beneath the lubricating layer 18 through the gaps in the lubricating layer 18. These environmental substances penetrating beneath the lubricating layer 18 adsorb and bind to the protective layer 17, generating contaminants. During magnetic recording and reproduction, these contaminants (agglomerated components) adhere (transfer) to the magnetic head as stains, causing head damage or reducing the magnetic recording and reproduction characteristics of the magnetic recording and reproduction device.

[0263] Examples of environmental pollutants include: siloxane compounds (cyclic siloxanes, linear siloxanes), ionic impurities, high molecular weight hydrocarbons such as octadecane, and plasticizers such as dioctyl phthalate. Examples of metal ions contained in ionic impurities include: sodium ions and potassium ions. Examples of inorganic ions contained in ionic impurities include: chloride ions, bromide ions, nitrate ions, sulfate ions, and ammonium ions. Examples of organic ions contained in ionic impurities include: oxalate ions and formate ions.

[0264] "Methods for forming a lubricating layer"

[0265] As a method for forming the lubricating layer 18, the following methods can be listed: preparing a magnetic recording medium in the manufacturing process on which each layer up to the protective layer 17 is formed on the substrate 11, applying a lubricating layer forming solution to the protective layer 17, and drying it.

[0266] The solution for forming the lubricating layer can be obtained by dispersing and dissolving the lubricant for the magnetic recording medium described in the above embodiments in a solvent as needed, and adjusting the viscosity and concentration to be suitable for the coating method.

[0267] Solvents used in solutions for forming lubricating layers include, for example, fluorinated solvents such as Bartel XF (trade name, manufactured by Mitsui Dupont Fluorokemica Co., Ltd.).

[0268] There are no particular restrictions on the application method of the solution for forming the lubricating layer; examples include spin coating, spray coating, paper coating, and impregnation.

[0269] When using the immersion method, the following method can be used, for example. First, a substrate 11, with each layer up to the protective layer 17, is immersed in a lubricant layer forming solution placed in an immersion tank of an immersion coating apparatus. Then, the substrate 11 is lifted out of the immersion tank at a predetermined speed. As a result, the lubricant layer forming solution is applied to the surface of the protective layer 17 of the substrate 11.

[0270] By using the impregnation method, the lubricating layer forming solution can be uniformly coated on 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.

[0271] In this embodiment, it is preferable to perform heat treatment on the substrate 11 on which the lubricating layer 18 is formed. By performing heat treatment, the adhesion between the lubricating layer 18 and the protective layer 17 is improved, and the bonding force between the lubricating layer 18 and the protective layer 17 is enhanced.

[0272] The heat treatment temperature is preferably set to 100–180°C. If the heat treatment temperature is above 100°C, the effect of improving the adhesion between the lubricating layer 18 and the protective layer 17 can be fully achieved. Furthermore, by setting the heat treatment temperature below 180°C, thermal decomposition of the lubricating layer 18 can be prevented. The heat treatment time is preferably set to 10–120 minutes.

[0273] In this embodiment, in order to further improve the adhesion of the lubricating layer 18 to the protective layer 17, the lubricating layer 18 of the substrate 11 before or after heat treatment may be subjected to ultraviolet (UV) irradiation treatment.

[0274] The magnetic recording medium 10 of this embodiment has at least a magnetic layer 16, a protective layer 17, and a lubricating layer 18 sequentially disposed on a substrate 11. In the magnetic recording medium 10 of this embodiment, a lubricating layer 18 comprising the aforementioned fluorinated ether compound is formed in contact with each other on the protective layer 17. Even though the lubricating layer 18 is thin, it covers the surface of the protective layer 17 with a high coverage rate. Therefore, in the magnetic recording medium 10 of this embodiment, environmental substances that generate ionic impurities and other contaminants are prevented from intruding through the gaps in the lubricating layer 18. Consequently, there are fewer contaminants on the surface of the magnetic recording medium 10 of this embodiment. Furthermore, the lubricating layer 18 in the magnetic recording medium 10 of this embodiment is less prone to the formation of foreign matter (stains), and adhesion can be suppressed. In addition, the lubricating layer 18 in the magnetic recording medium 10 of this embodiment has excellent heat resistance and wear resistance. Therefore, the magnetic recording medium 10 of this embodiment has excellent reliability and durability.

[0275] Example

[0276] The present invention will be further described in detail below through embodiments and comparative examples. It should be noted that the present invention is not limited to the following embodiments.

[0277] (Example 1)

[0278] The compound represented by formula (A) above is prepared by the method shown below.

[0279] Under a nitrogen atmosphere, add HOCH2CF2O(CF2CF2O)m(CF2O) to a 100 mL round-bottom flask. n 40 g of the compound represented by CF2CH2OH (where m is 4.5 and n is 4.5) (number average molecular weight 1000, molecular weight distribution 1.1), 6.5 g of the compound represented by formula (8) below (molecular weight 272.3, 24 mmol), and 38 mL of tert-butanol (t-BuOH) were stirred at room temperature until homogeneous. 1.4 g of potassium tert-butoxide (t-BuOK) (molecular weight 112.21, 12 mmol) was further added to this homogeneous liquid, and the mixture was stirred at 70 °C for 16 hours to allow the reaction to proceed.

[0280] The compound represented by formula (8) was synthesized by oxidizing a double bond group of the compound in which the hydroxyl group of glycerol α,α'-diallyl ether was protected by dihydropyran.

[0281] The obtained reaction product was cooled to 25°C and transferred to a separatory funnel containing 100 mL of water. It was extracted three times with 100 mL of ethyl acetate. The organic layer was washed with water and dehydrated using anhydrous sodium sulfate. After filtering to separate the drying agent, the filtrate was concentrated, and the residue was purified by silica gel column chromatography. By performing the above steps, 20.2 g of the compound represented by the following formula (9) (molecular weight 1272.3, 15.9 mmol) as an intermediate was obtained.

[0282]

[0283] In formula (8), THP represents tetrahydropyranyl.

[0284] In equation (9), m, which represents the average degree of polymerization, is 4.5, n, which represents the average degree of polymerization, is 4.5, and THP represents tetrahydropyranyl.

[0285] Under a nitrogen atmosphere, 6.4 g of the compound represented by formula (9) as an intermediate (molecular weight 1272.3, 5.0 mmol), 1.1 g of the compound represented by formula (10) below (molecular weight 201.3, 5.5 mmol), and 2.4 mL of tert-butanol were added to a 100 mL flask and stirred at room temperature until homogeneous. 1.87 g of potassium tert-butoxide (molecular weight 112.21, 25.2 mmol) was added to the homogeneous liquid, and the mixture was stirred at 70 °C for 22.5 hours to allow the reaction to proceed.

[0286] The compound represented by formula (10) was synthesized by reacting epibromool with the primary hydroxyl group of 4-(3-hydroxypropyl)morpholine.

[0287]

[0288] The reaction solution was brought to room temperature, and 26 g of a 10% hydrogen chloride-methanol solution (hydrogen chloride-methanol reagent (5-10%), manufactured by Tokyo Chemical Industry Co., Ltd.) was added. The mixture was stirred at room temperature for 3.5 hours. The reaction solution was transferred dropwise to a separatory funnel containing 100 mL of saline solution and extracted twice with 200 mL of ethyl acetate. The organic layer was washed successively with 100 mL of saline solution, 100 mL of saturated sodium bicarbonate solution, and 100 mL of saline solution, and dehydrated using anhydrous sodium sulfate. After filtering to separate the drying agent (anhydrous sodium sulfate), the filtrate was concentrated, and the residue was purified by silica gel column chromatography. Through the above steps, 4.6 g (3.3 mmol) of compound (A) (in formula (A), ma, representing the average degree of polymerization, is 4.5, and na, representing the average degree of polymerization, is 4.5) was obtained.

[0289] The obtained compound (A) was subjected to 1 H-NMR measurements and 19The structure was identified by F-NMR measurements, and the following results were obtained.

[0290] 1 H-NMR (CD3COCD3): δ [ppm] 1.6~1.7(2H), 2.4~2.5(6H), 3.4~4.2(30H), 5.1~5.2(1H), 5.2~5.3(1H), 5.8~5.9(1H)

[0291] 19 F-NMR (CD3COCD3): δ [ppm] = -55.6~-50.6(9F), -77.7(2F), -80.3(2F), -91.0~-88.5(18F)

[0292] (Example 2)

[0293] Using 6.6g of the compound represented by formula (11) instead of the compound represented by formula (8), and using 1.0g of the compound represented by formula (12) instead of the compound represented by formula (10), the same operation as in Example 1 was performed to obtain 4.7g of the compound represented by formula (B) (in formula (B), mb, which represents the average degree of polymerization, is 4.5, and nb, which represents the average degree of polymerization, is 4.5).

[0294]

[0295] In formula (11), MOM represents methoxymethyl.

[0296]

[0297] The compound represented by formula (11) was synthesized by the following method. Epibromoethanol was reacted with the primary hydroxyl group of ethylene glycol monoallyl ether, and the resulting compound was reacted with sulfuric acid to give a diol. The primary hydroxyl group of the resulting diol was protected with tert-butyldimethylsilyl ether using tert-butyldimethylsilane, and the secondary hydroxyl group was protected with a methoxymethyl (MOM) group using chloromethyl methyl ether. The tert-butyldimethylsilyl ether of the resulting compound was removed, and the resulting primary hydroxyl group was reacted with epibromoethanol. Through the above steps, the compound represented by formula (11) was obtained.

[0298] The compound represented by formula (12) is synthesized by reacting epibromoethanol with the primary hydroxyl group of 1-piperidineethanol.

[0299] The obtained compound (B) was subjected to 1 H-NMR measurements and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0300] 1H-NMR (CD3COCD3): δ [ppm] 1.5~1.6(6H), 2.5~2.8(6H), 3.4~4.2(30H), 5.1~5.2(1H), 5.2~5.3(1H), 5.8~5.9(1H)

[0301] 19 F-NMR (CD3COCD3): δ [ppm] = -55.6~-50.6(9F), -77.7(2F), -80.3(2F), -91.0~-88.5(18F)

[0302] (Example 3)

[0303] Using 6.6 g of the compound represented by formula (13) instead of the compound represented by formula (8), and using 0.9 g of the compound represented by formula (14) instead of the compound represented by formula (10), the same operation as in Example 1 was performed to obtain 4.6 g of the compound represented by formula (C) (in formula (C), mc, representing the average degree of polymerization, is 4.5, and nc, representing the average degree of polymerization, is 4.5).

[0304]

[0305] In formula (13), MOM represents methoxymethyl.

[0306]

[0307] For the compound represented by formula (13), 2-(2-propynoxy)ethanol is used instead of ethylene glycol monoallyl ether, and the same operation as that for the compound represented by formula (11) is performed for synthesis.

[0308] The compound represented by formula (14) is synthesized by reacting epibromool with the primary hydroxyl group of 1-(2-hydroxyethyl)pyrrolidine.

[0309] The obtained compound (C) was subjected to 1 H-NMR measurements and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0310] 1 H-NMR (CD3COCD3): δ [ppm] 1.6~1.7(4H), 2.5~2.8(7H), 3.4~4.2(30H)

[0311] 19 F-NMR (CD3COCD3): δ [ppm] = -55.6~-50.6(9F), -77.7(2F), -80.3(2F), -91.0~-88.5(18F)

[0312] (Example 4)

[0313] Using 6.6g of the compound represented by formula (11) above instead of the compound represented by formula (8), and using 0.9g of the compound represented by formula (15) below instead of the compound represented by formula (10), the same operation as in Example 1 was performed to obtain 4.6g of the compound represented by formula (D) above (in formula (D), md, which represents the average degree of polymerization, is 4.5, and nd, which represents the average degree of polymerization, is 4.5).

[0314]

[0315] The compound represented by formula (15) is synthesized by reacting epibromool with the primary hydroxyl group of 3-(dimethylamino)-1-propanol.

[0316] The obtained compound (D) was subjected to 1 H-NMR measurements and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0317] 1 H-NMR (CD3COCD3): δ [ppm] 1.7~1.8(2H), 2.3(6H), 2.5~2.6(2H), 3.4~4.2(32H), 5.1~5.2(1H), 5.2~5.3(1H), 5.8~5.9(1H)

[0318] 19 F-NMR (CD3COCD3): δ [ppm] = -55.6~-50.6(9F), -77.7(2F), -80.3(2F), -91.0~-88.5(18F)

[0319] (Example 5)

[0320] Using HOCH2CF2O(CF2CF2O) m′ (CF2O) n′ The compound represented by CF2CH2OH (where m' represents the average degree of polymerization and n' represents the average degree of polymerization and n' is 0) (number average molecular weight 1000, molecular weight distribution 1.1) is used instead of HOCH2CF2O (CF2CF2O) in Example 1. m (CF2O) nThe compound represented by CF2CH2OH (where m represents the average degree of polymerization and n represents the average degree of polymerization of 4.5) (number average molecular weight 1000, molecular weight distribution 1.1), and 1.0 g of the compound represented by formula (16) below instead of the compound represented by formula (10), were obtained by performing the same operation as in Example 1, except that the compound represented by formula (E) above (where me represents the average degree of polymerization of 7.1) was obtained.

[0321]

[0322] The compound represented by formula (16) was synthesized by reacting epibromool with the primary hydroxyl group of 4-(2-hydroxyethyl)morpholine.

[0323] The obtained compound (E) was subjected to 1 H-NMR measurements and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0324] 1 H-NMR (CD3COCD3): δ [ppm] 2.4~2.5(6H), 3.4~4.2(30H), 5.1~5.2(1H), 5.2~5.3(1H), 5.8~5.9(1H)

[0325] 19 F-NMR (acetone-D6): δ[ppm]=-78.6(2F), -81.3(2F), -90.0~-88.5(28F)

[0326] (Example 6)

[0327] Using HOCH2CF2O(CF2CF2O) m′ (CF2O) n′ The compound represented by CF2CH2OH (where m' represents the average degree of polymerization and n' represents the average degree of polymerization and n' is 0) (number average molecular weight 1000, molecular weight distribution 1.1) is used instead of HOCH2CF2O (CF2CF2O) in Example 1. m (CF2O) nThe compound represented by CF2CH2OH (where m represents the average degree of polymerization and n represents the average degree of polymerization of 4.5) (number average molecular weight 1000, molecular weight distribution 1.1) was used in place of the compound represented by formula (8) with 5.2 g of the compound represented by formula (17) below, and the compound represented by formula (10) with 1.0 g of the compound represented by formula (16) above. Otherwise, the same operation as in Example 1 was performed to obtain 4.6 g of the compound represented by formula (F) above (where mf represents the average degree of polymerization of 7.1).

[0328]

[0329] The compound represented by formula (17) is synthesized by reacting 3-buten-1-ol with epichlorohydrin and oxidizing one of the double bond groups of the resulting compound.

[0330] The obtained compound (F) was subjected to 1 H-NMR measurements and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0331] 1 H-NMR (CD3COCD3): δ [ppm] 1.6~1.8(2H), 2.3~2.4(2H), 2.4~2.5(6H), 3.4~4.2(30H), 5.1~5.2(1H), 5.2~5.3(1H), 5.8~5.9(1H)

[0332] 19 F-NMR (acetone-D6): δ[ppm]=-78.6(2F), -81.3(2F), -90.0~-88.5(28F)

[0333] (Example 7)

[0334] Using HOCH2CF2O(CF2CF2O) m′ (CF2O) n′ The compound represented by CF2CH2OH (where m' represents the average degree of polymerization and n' represents the average degree of polymerization and n' is 0) (number average molecular weight 1000, molecular weight distribution 1.1) is used instead of HOCH2CF2O (CF2CF2O) in Example 1. m (CF2O) nThe compound represented by CF2CH2OH (where m represents the average degree of polymerization and n represents the average degree of polymerization of 4.5) (number average molecular weight 1000, molecular weight distribution 1.1) was used. 5.2g of the compound represented by formula (17) was used instead of the compound represented by formula (8), and 1.8g of the compound represented by formula (18) was used instead of the compound represented by formula (10). Otherwise, the same operation as in Example 1 was performed to obtain 4.8g of the compound represented by formula (G) (where mg represents the average degree of polymerization of 7.1) as described above.

[0335]

[0336] In formula (18), THP represents tetrahydropyranyl.

[0337] The compound represented by formula (18) was synthesized by the following method: Allyl glycidyl ether was reacted with the primary hydroxyl group of 2-diethylaminoethanol. The primary hydroxyl group of the resulting compound was protected with a tetrahydropyranyl (THP) group, and the terminal double bond of the resulting compound was oxidized. Through the above steps, the compound represented by formula (18) was obtained.

[0338] The obtained compound (G) was subjected to 1 H-NMR measurements and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0339] 1 H-NMR (CD3COCD3): δ[ppm]1.0(6H), 1.6~1.8(2H), 2.3~2.4(2H), 2.5~2.6(6H), 3.4~4.2(32H), 5.1~5.2(1H), 5.2~5.3(1H), 5.8~5.9(1H)

[0340] 19 F-NMR (acetone-D6): δ[ppm]=-78.6(2F), -81.3(2F), -90.0~-88.5(28F)

[0341] (Example 8)

[0342] Using HOCH2CF2O(CF2CF2O) m′ (CF2O) n′ The compound represented by CF2CH2OH (where m' represents the average degree of polymerization and n' represents the average degree of polymerization and n' is 0) (number average molecular weight 1000, molecular weight distribution 1.1) is used instead of HOCH2CF2O (CF2CF2O) in Example 1. m (CF2O) nThe compound represented by CF2CH2OH (where m represents the average degree of polymerization and n represents the average degree of polymerization) (number average molecular weight 1000, molecular weight distribution 1.1) was replaced with 6.2g of the compound represented by formula (19) below instead of the compound represented by formula (8), and 2.0g of the compound represented by formula (20) below instead of the compound represented by formula (10). Otherwise, the same operation as in Example 1 was performed to obtain 4.9g of the compound represented by formula (H) above (where mh represents the average degree of polymerization and 7.1).

[0343]

[0344] In formula (19), MOM represents methoxymethyl.

[0345]

[0346] In formula (20), THP represents tetrahydropyranyl.

[0347] The compound represented by formula (19) was synthesized by the following method: The primary hydroxyl group of 3-(4-pentenyloxy)-1,2-propanediol was protected with a tert-butyldimethylsilyl (TBS) group, and the secondary hydroxyl group of the resulting compound was protected with a methoxymethyl (MOM) group. Then, the compound was synthesized by reacting the compound obtained after removing the TBS group with epibromool.

[0348] The compound represented by formula (20) was synthesized by the following method: Allyl glycidyl ether was reacted with the primary hydroxyl group of hexahydro-1H-aza-1-ethanol. The secondary hydroxyl group of the resulting compound was protected with a THP group, and the terminal double bond of the resulting compound was oxidized. Through the above steps, the compound represented by formula (20) was obtained.

[0349] The obtained compound (H) was subjected to 1 H-NMR measurements and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0350] 1 H-NMR (CD3COCD3): δ [ppm] 1.6~1.8(10H), 2.3~2.4(2H), 2.4~2.7(6H) 3.4~4.2(32H), 5.1~5.2(1H), 5.2~5.3(1H), 5.8~5.9(1H)

[0351] 19 F-NMR (acetone-D6): δ[ppm]=-78.6(2F), -81.3(2F), -90.0~-88.5(28F)

[0352] (Example 9)

[0353] Use HOCH2CF2CF2O(CF2CF2CF2O) p The compound represented by CF2CF2CH2OH (where p represents the average degree of polymerization, which is 4.4) (number average molecular weight 1000, molecular weight distribution 1.1) is used instead of HOCH2CF2O (CF2CF2O) in Example 1. m (CF2O) n The compound represented by CF2CH2OH (where m represents the average degree of polymerization and n represents the average degree of polymerization of 4.5) (number average molecular weight 1000, molecular weight distribution 1.1) was used in place of 6.6g of the compound represented by formula (13) above instead of the compound represented by formula (8), and 1.9g of the compound represented by formula (21) below instead of the compound represented by formula (10). Otherwise, the same operation as in Example 1 was performed to obtain 4.9g of the compound represented by formula (I) above (where pi represents the average degree of polymerization of 4.4 in formula (I)).

[0354]

[0355] In formula (21), THP represents tetrahydropyranyl.

[0356] The compound represented by formula (21) was synthesized by the following method: Allyl glycidyl ether was reacted with the primary hydroxyl group of 1-(3-hydroxypropyl)pyrrolidine. The secondary hydroxyl group of the resulting compound was protected with a THP group, and the terminal double bond of the resulting compound was oxidized. Through the above steps, the compound represented by formula (21) was obtained.

[0357] The obtained compound (I) was subjected to 1 H-NMR measurements and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0358] 1 H-NMR (CD3COCD3): δ[ppm]=1.7~1.8(2H), 1.8~1.9(4H), 2.5~2.8(7H), 3.4~4.2(36H)

[0359] 19 F-NMR (acetone-D6): δ[ppm]=-84.0~-83.0(18F), -86.4(4F), -124.3(4F), -130.0~-129.0(9F)

[0360] (Comparative Example 1)

[0361] The compound represented by the following formula (J) was synthesized by the following method.

[0362] From HOCH2CF2O(CF2CF2O) m (CF2O) n 4.20 g of the compound represented by CF2CH2OH (where m represents the average degree of polymerization and n represents the average degree of polymerization and 4.5) (number average molecular weight 1000, molecular weight distribution 1.1) was used to obtain 4.12 g of the compound represented by the following formula (22) with glycidyl groups at the molecular ends.

[0363] Next, 40 mL of a 50% by mass aqueous solution of dimethylamine was added to the compound represented by formula (22), and the mixture was stirred at room temperature for 4 hours to allow the reaction to proceed. The organic layer was separated from the reaction product obtained after the reaction, dissolved in 100 mL of bartel (registered trademark) XF, and dehydrated by anhydrous sodium sulfate. After filtering with a drying agent, the filtrate was concentrated, thereby synthesizing 3.97 g (3.3 mmol) of compound (J).

[0364]

[0365] In equation (22), m represents the average degree of polymerization and n represents the average degree of polymerization and n is 4.5.

[0366] In equation (J), mj, representing the average degree of polymerization, is 4.5, and nj, representing the average degree of polymerization, is 4.5.

[0367] The obtained compound (J) was subjected to 1 H-NMR measurements and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0368] 1 H-NMR (CDCl3): δ[ppm]=2.3(12H), 2.4~2.5(4H), 3.4~4.2(12H)

[0369] 19 F-NMR (CD3COCD3): δ [ppm] = -55.6~-50.6(9F), -77.7(2F), -80.3(2F), -91.0~-88.5(18F)

[0370] (Comparative Example 2)

[0371] The compound represented by the following formula (K) was synthesized using the method described in Patent Document 6.

[0372]

[0373] In equation (K), mk, representing the average degree of polymerization, is 4.5, and nk, representing the average degree of polymerization, is 4.5.

[0374] The obtained compound (K) was subjected to 1 H-NMR measurements and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0375] 1 H-NMR (CDCl3): δ[ppm]=3.5~4.0(20H), 5.1~5.3(4H), 5.9(2H)

[0376] 19 F-NMR (CD3COCD3): δ [ppm] = -55.6~-50.6(9F), -77.7(2F), -80.3(2F), -91.0~-88.5(18F)

[0377] (Comparative Example 3)

[0378] The compound represented by the following formula (L) was synthesized using the method described in Patent Document 7.

[0379]

[0380] In formula (L), ml, representing the average degree of polymerization, is 4.5, and nl, representing the average degree of polymerization, is 4.5.

[0381] The obtained compound (L) was subjected to 1 H-NMR measurements and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0382] 1 H-NMR (CD3COCD3): δ[ppm]=1.6~1.8(4H), 3.1(2H), 3.5~4.2(21H), 5.1~5.3(2H), 5.9(1H)

[0383] 19 F-NMR (CD3COCD3): δ [ppm] = -55.6~-50.6(9F), -77.7(2F), -80.3(2F), -91.0~-88.5(18F)

[0384] (Comparative Example 4)

[0385] The compound represented by the following formula (M) was synthesized using the method described in Patent Document 2.

[0386]

[0387] In formula (M), mm represents the average degree of polymerization and nm represents the average degree of polymerization.

[0388] The obtained compound (M) was subjected to 1 The structure was identified by H-NMR measurements, and the following results were obtained.

[0389] 1 H-NMR (CD3COCD3): δ[ppm]=3.5~4.3(23H), 5.1~5.3(2H), 5.9(1H), 6.2(1H), 7.3(1H)

[0390] (Comparative Example 5)

[0391] The compound represented by the following formula (N) was synthesized by the following method.

[0392] Add 2.5 g of trifluoromethanesulfonyl chloride and 0.92 g of dimethylaminopyridine, and stir at -20°C. Then, add HOCH₂CF₂O (CF₂CF₂O) dropwise. m (CF2O) n 5.0 g of a compound represented by CF2CH2OH (where m represents the average degree of polymerization and n represents the average degree of polymerization, both of which are 4.5) (number average molecular weight 1000, molecular weight distribution 1.1) was reacted for 2 hours.

[0393] The reaction product was brought to room temperature and transferred to a separatory funnel containing 100 mL of water. It was extracted three times with 100 mL of ethyl acetate. The organic layer was washed with water and dehydrated using anhydrous sodium sulfate. After filtering to separate the drying agent, the filtrate was concentrated, and the residue was purified by silica gel column chromatography. By performing the above steps, 6.4 g of the compound represented by the following formula (23) (molecular weight 1264, 5.1 mmol) as an intermediate was obtained.

[0394]

[0395] In equation (23), m, representing the average degree of polymerization, is 4.5, and n, representing the average degree of polymerization, is 4.5.

[0396] In a nitrogen atmosphere, 6.0 g of the compound represented by formula (23) as an intermediate (molecular weight 1264.1, 4.8 mmol), 1.8 g of the commercially available compound represented by formula (24) below (manufactured by UORSY, molecular weight 129.20, 14.2 mmol) and 12.4 mL of acetonitrile were added to a 100 mL flask and stirred at room temperature until homogeneous. The mixture was then heated under reflux and stirred for 6 hours.

[0397] The reaction product was cooled to 25°C and transferred to a separatory funnel containing 100 mL of saturated sodium bicarbonate solution. It was extracted three times with 100 mL of ethyl acetate. The organic layer was washed with water and dehydrated using anhydrous sodium sulfate. After filtering to separate the drying agent, the filtrate was concentrated, and the residue was purified by silica gel column chromatography. Through the above steps, 4.0 g (3.3 mmol) of compound (N) was obtained (in formula (N), where mn represents the average degree of polymerization and nn represents the average degree of polymerization, respectively).

[0398]

[0399] In equation (N), mn represents the average degree of polymerization and is 4.5, and nn represents the average degree of polymerization and is 4.5.

[0400] The obtained compound (N) was subjected to 1 The structure was identified by H-NMR measurements, and the following results were obtained.

[0401] 1 H-NMR (CD3COCD3): δ[ppm]=1.6~1.8(6H), 2.3~2.4(4H), 2.5~2.8(12H), 3.5~4.1(6H), 5.4~5.5(4H)

[0402] The compounds obtained in Examples 1-9 are thus applied to R in formula (1). 1 The structure, a, z, [X], [Y], R in equation (3) 3 Structure, R 4 Structure, R 5 The structure is shown in Table 1.

[0403] In addition, through the above 1 H-NMR and 19 The number-average molecular weights (Mn) of the compounds in Examples 1-9 and Comparative Examples 1-5 were determined by 1 / 2-NMR spectroscopy. The results are shown in Table 2.

[0404] Table 1

[0405]

[0406] Table 2

[0407]

[0408] Next, a lubricant layer forming solution was prepared using the compounds obtained in Examples 1-9 and Comparative Examples 1-5, according to the method shown below. Then, using the obtained lubricant layer forming solution, a lubricant layer of the magnetic recording medium was formed by the method shown below, thus obtaining the magnetic recording media of Examples 1-9 and Comparative Examples 1-5.

[0409] "Solution for forming a lubricating layer"

[0410] The compounds obtained in Examples 1-9 and Comparative Examples 1-5 were dissolved in Virtue XF (registered trademark) (trade name, manufactured by Mitsui Dupont Fluoroke Microcar Co., Ltd.), a fluorine solvent, and diluted with Virtue XF to achieve a film thickness suitable for coating on the protective layer. Prepare a solution for forming a lubricating layer.

[0411] "Magnetic recording medium"

[0412] A magnetic recording medium is prepared by sequentially depositing an adhesion layer, a soft magnetic layer, a first substrate layer, a second substrate layer, a magnetic layer, and a protective layer on a substrate with a diameter of 65 mm. The protective layer is made of carbon.

[0413] On the protective layer of the magnetic recording medium, which has formed each layer up to the protective layer, the lubricating layer forming solutions of Examples 1-9 and Comparative Examples 1-5 were applied by an impregnation method. It should be noted that the impregnation method was performed under the conditions of an impregnation speed of 10 mm / sec, an impregnation time of 30 sec, and a pull-out speed of 1.2 mm / sec.

[0414] Then, the magnetic recording medium coated with the lubricant layer forming solution is placed in a constant temperature bath at 120°C and heated for 10 minutes to remove the solvent from the lubricant layer forming solution, thereby forming a lubricant layer on the protective layer, and thus obtaining the magnetic recording medium.

[0415] The film thickness of the lubricating layer of the magnetic recording media of Examples 1-9 and Comparative Examples 1-5 obtained by this procedure was measured using FT-IR (trade name: Nicolet iS50, manufactured by Thermo Fisher Scientific). The results are shown in Table 2.

[0416] Next, the magnetic recording media of Examples 1-9 and Comparative Examples 1-5 were subjected to the wear resistance tests shown below.

[0417] (Abrasion resistance test)

[0418] Using a pin-disc tribological testing machine, an alumina ball with a diameter of 2 mm, serving as the contact, was slid across the lubricating layer of a magnetic recording medium under a load of 40 gf and a sliding speed of 0.25 m / sec. The coefficient of friction on the surface of the lubricating layer was measured. Then, the sliding time until the coefficient of friction on the surface of the lubricating layer increased sharply was measured. The sliding time until the coefficient of friction increased sharply was measured four times for each lubricating layer of the magnetic recording medium, and the average time was used as an indicator of the wear resistance of the lubricant coating (time for coefficient of friction to increase). The results for magnetic recording media using the compounds of Examples 1-9 and Comparative Examples 1-5 are shown in Table 2. The evaluation of the time for coefficient of friction to increase is as follows. It should be noted that the longer the time until the coefficient of friction increases sharply, the better the wear resistance, and therefore this is preferred.

[0419] Evaluation Criteria

[0420] A: Over 850 seconds

[0421] B: 750 seconds or more but less than 850 seconds

[0422] C: 650 seconds or more but less than 750 seconds

[0423] D: 550 seconds or more but less than 650 seconds

[0424] E: 450 seconds or more but less than 550 seconds

[0425] It should be noted that the time until the coefficient of friction increases sharply can be used as an indicator of the wear resistance of the lubricating layer for the following reasons. This is because the lubricating layer of the magnetic recording medium wears down due to the use of the magnetic recording medium. If the wear causes the lubricating layer to disappear, the contact will directly contact the protective layer, and the coefficient of friction will increase sharply. Therefore, the time until the coefficient of friction increases sharply can be considered related to the friction test.

[0426] As shown in Table 2, the magnetic recording media of Examples 1-9, having a lubricating layer containing the compound represented by formula (1), exhibit good wear resistance. It is presumed that this is because of the R in the compounds of Examples 1-9. 1 The alkenyl or ynyl groups exhibit good interaction with the protective layer, and R 5 The tertiary amine (-NR) it possesses 6 R 7 It has a moderate volume, so that the coverage of the protective layer can be properly maintained without compromising the tightness of the protective layer.

[0427] In contrast, as shown in Table 2, the magnetic recording media of Comparative Examples 1-5 exhibited poor wear resistance compared to Examples 1-9. This is presumably because the lubricating layer containing the compounds of Comparative Examples 1-5 had difficulty achieving a tight seal with the protective layer.

[0428] Next, the compounds of Examples 1-9 and Comparative Examples 1-5 were subjected to the following heat resistance tests.

[0429] (Heat resistance test)

[0430] Thermal decomposition measurements of the compounds in Examples 1-9 and Comparative Examples 1-5 were performed in nitrogen and air using a thermogravimetric differential thermal analysis (TG-DTA) apparatus (manufactured by Bruker, product name Galaxy). The results are shown in Table 2. The evaluation of the exothermic onset temperature is as follows. It should be noted that a higher exothermic onset temperature indicates better heat resistance and is therefore preferred.

[0431] Evaluation Criteria

[0432] A: Above 240℃

[0433] B: Temperature above 200℃ and below 240℃

[0434] C: Temperature above 180℃ and below 200℃

[0435] D: Temperature above 140℃ and below 180℃

[0436] E: Below 140℃

[0437] As shown in Table 2, Examples 1-9, which are compounds represented by formula (1), exhibit high exothermic onset temperatures in nitrogen and air, and good heat resistance. It is speculated that this is due to R... 5 The tertiary amine (-NR) it possesses 6 R 7 R acts as a free radical scavenger, thereby 1 The presence of alkenyl or alkynyl groups enhances heat resistance and reduces the likelihood of thermally induced oxidative decomposition. Furthermore, the results from Examples 1-9 confirm that tertiary amines (-NR) exhibit improved heat resistance. 6 R 7 When the radical is morpholino, exceptionally good heat resistance can be obtained.

[0438] As shown in Table 2, the compounds of Comparative Examples 1 and 5 did not exhibit a difference in exothermic onset temperature between nitrogen and air, demonstrating the same level of heat resistance as the examples. This is presumably because the compounds of Comparative Examples 1 and 5 contain tertiary amines.

[0439] In contrast, the compounds of Comparative Examples 2 and 3, which contain alkenyl groups but not tertiary amines, exhibited poor heat resistance. It is presumed that this is because the alkenyl groups in the compounds of Comparative Examples 2 and 3 are oxidized and decomposed by heat.

[0440] Furthermore, Comparative Example 4 exhibited the same level of heat resistance as the Examples in nitrogen, but its exothermic onset temperature in air was low, resulting in poor heat resistance. This is presumably because the unsaturated heterocycles containing nitrogen atoms decompose upon heating, reducing their ability to capture free radicals from these nitrogen-containing unsaturated heterocycles.

[0441] Furthermore, the compounds and magnetic recording media of Examples 1-9 and Comparative Examples 1-5 were comprehensively evaluated based on the criteria shown below. The results are shown in Table 2.

[0442] Evaluation Criteria

[0443] A: The abrasion resistance test is rated A or B, and the heat resistance test (in air) is rated A.

[0444] B: The abrasion resistance test is rated A or B, and the heat resistance test (in air) is rated B.

[0445] C: The abrasion resistance test is rated C, and the heat resistance test (in air) is rated A to C.

[0446] D: The abrasion resistance test is rated C, and the heat resistance test (in air) is rated D or E; or the abrasion resistance test is rated D or E, and the heat resistance test (in air) is rated A to C.

[0447] E: The abrasion resistance test is rated D or E, and the heat resistance test (in air) is rated D or E.

[0448] As shown in Table 2, the overall evaluation of Examples 1-9, which used compounds represented by Formula (1), was A or B. In contrast, the overall evaluation of Comparative Examples 1 and 3-5 was D, and the overall evaluation of Comparative Example 2 was E.

[0449] Industrial availability

[0450] The present invention provides a fluorinated ether compound that is suitable as a material for a lubricant for magnetic recording media capable of forming a lubricating layer with excellent wear resistance and heat resistance.

[0451] By using a lubricant for magnetic recording media containing the fluorinated ether compound of the present invention, a lubricating layer with excellent wear resistance and heat resistance can be formed even with a thin thickness.

[0452] Symbol Explanation

[0453] 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 fluorinated ether compound, characterized in that, It can be represented by the following formula (1): R 1 -O-R 2 -CH2-R 3 -CH2-R 4 -R 5 (1) In equation (1), R 3 It is a perfluoropolyether chain; R 1 It is an alkenyl group with 2 to 8 carbon atoms or an alkynyl group with 3 to 8 carbon atoms; -R 2 - Represented by the following formula (3); -R 4 - Represented by the following formula (4); -R 5 The group represented by the following formula (2); -((CH2) a -EITHER) z -[X]-[Y]- (3) In equation (3), a represents an integer from 1 to 3, and z represents 0 or 1; [X] is represented by the following equation (X), and [Y] is represented by the following equation (Y). The bond order of [X] and [Y] can be reversed; however, the sum of c in equation (X) and e in equation (Y) is 1 or 2. In equation (X), b is an integer from 1 to 3, and c is an integer from 0 to 2; In equation (Y), d is an integer from 2 to 3, and e is an integer from 0 to 2; In equation (4), f is an integer from 1 to 2; -O-(CH2) g -N-R 6 R 7 (2) In equation (2), g is an integer of 2 or 3; R 6 and R 7 Each is independently a saturated aliphatic group having 1 to 4 carbon atoms, or R 6 and R 7 It forms 5- to 7-membered rings together with nitrogen atoms.

2. The fluorinated ether compound according to claim 1, wherein R 2 The hydroxyl groups contained therein are the same as those of the R. 4 The total number of hydroxyl groups contained is 3 or more.

3. The fluorinated ether compound according to claim 1 or 2, wherein -NR in formula (2) 6 R 7 It is dimethylamino or diethylamino.

4. The fluorinated ether compound according to claim 1 or 2, wherein -NR in formula (2) 6 R 7 It is any one of the groups selected from pyrrolidinyl, piperidinyl, morpholinyl, and hexamethyleneimine.

5. The fluorinated ether compound according to claim 1 or 2, wherein R in formula (1) above... 1 It is any one of the groups selected from vinyl, allyl, 3-butenyl, 4-pentenyl, and propargyl.

6. The fluorinated ether compound according to claim 1 or 2, wherein R 3 It is any one of the following formulas (5) to (7): -CF2O-(CF2CF2O) h -(CF2O) i -CF2- (5) In equation (5), h and i represent the average degree of polymerization, which range from 0 to 30 respectively. However, h and i are not both 0 at the same time. -CF(CF3)-(OCF(CF3)CF2) j -OCF(CF3)- (6) In equation (6), j represents the average degree of polymerization, ranging from 0.1 to 30. -CF2CF2O-(CF2CF2CF2O) k -CF2CF2- (7) In equation (7), k represents the average degree of polymerization, which ranges from 0.1 to 30.

7. The fluorinated ether compound according to claim 1 or 2, wherein the number average molecular weight is in the range of 500 to 10,000.

8. The fluorinated ether compound according to claim 1, wherein the compound represented by formula (1) is any one of the compounds represented by formulas (A), (B), (E), (F), and (I) below: In formula (A), ma and na represent the average degree of polymerization, where ma represents 1 to 30 and na represents 0 to 30. In formula (B), mb and nb represent the average degree of polymerization, where mb represents 1 to 30 and nb represents 0 to 30. In equation (E), me represents the average degree of polymerization, and me represents 0.1 to 30; In formula (F), mf represents the average degree of polymerization, and mf represents 0.1 to 30; In equation (I), pi represents the average degree of polymerization, and pi represents 0.1 to 30.

9. A lubricant for magnetic recording media, characterized in that, The compound comprising any one of claims 1 to 8.

10. A magnetic recording medium, comprising at least a magnetic layer, a protective layer, and a lubricating layer sequentially disposed on a substrate, characterized in that, The lubricating layer comprises any one of the fluorinated ether compounds according to claims 1 to 8.

11. The magnetic recording medium according to claim 10, wherein the average film thickness of the lubricating layer is 0.5 nm to 2.0 nm.

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