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

Abstract

fluorine-containing ether compounds represented by the following formulae. R 1 -CH2-R 2 -CH2-R 3 -CH2-R 4 -CH2-R 5 -CH2-R 6 -CH2-R 7 (R 2 , R 4 and R 6 are perfluoropolyether chains; R 3 is formula (2); R 5 is formula (3); R 1 and R 7 each independently is a terminal group comprising 2 or 3 polar groups, each polar group being bound to a different carbon atom, and the carbon atoms to which the polar groups are bound being bound to each other via a linking group comprising carbon atoms to which no polar group is bound.)

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. 2021-065869 filed on April 8, 2021, the contents of which are incorporated herein by reference. Background Technology

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

[0004] Conventionally, magnetic recording media consist of a recording layer formed on a substrate, upon which a protective layer, such as carbon, is formed. This protective layer protects the information recorded on the recording layer and improves the smoothness of the magnetic head. Furthermore, the protective layer covers the recording layer to prevent corrosion of the metal contained within it by environmental substances.

[0005] However, the durability of magnetic recording media cannot be fully achieved simply by applying a protective layer to the recording layer. Therefore, a lubricant is coated onto the surface of the protective layer, forming a lubricating layer with a thickness of approximately 0.5–3 nm. This lubricating layer improves the durability and protective strength of the protective layer, preventing contaminants from penetrating into the magnetic recording medium.

[0006] In addition, after a lubricating layer is formed on the surface of the protective layer, a polishing process is sometimes performed in order to remove protrusions and particles present on the surface of the magnetic recording medium and improve the smoothness of the surface.

[0007] As a lubricant used to form a lubricating layer for a magnetic recording medium, there are, for example, substances containing fluorine-based polymers having repeating structures including -CF2- and polar groups such as hydroxyl groups at the ends.

[0008] For example, Patent Document 1 discloses a disk having a lubricating layer comprising a fluorinated ether compound containing three perfluoropolyether chains within the molecule and having identical structures at both ends.

[0009] Patent document 2 discloses a disk having a lubricating layer comprising a fluorinated ether compound containing three perfluoropolyether chains within the molecule and having two structurally different ends.

[0010] Furthermore, Patent Document 3 discloses a disk having a lubricating layer comprising a lubricant containing three perfluoropolyether chains within the molecule and two hydroxyl groups on the linking groups between the perfluoropolyether chains.

[0011] Existing technical documents

[0012] Patent documents

[0013] Patent Document 1: International Publication No. 2018 / 116742

[0014] Patent Document 2: International Publication No. 2017 / 145995

[0015] Patent Document 3: U.S. Patent Application Publication No. 2016 / 0260452 Summary of the Invention

[0016] The problem that the invention aims to solve

[0017] In magnetic recording and playback devices, there is a further requirement to minimize the upward movement of the magnetic head. Therefore, it is necessary to make the lubricating layer in the magnetic recording medium thinner.

[0018] However, if the lubricating layer is too thin, the corrosion resistance of the magnetic recording medium may become insufficient. In particular, if a polishing process is performed on the surface of the magnetic recording medium after the lubricating layer has been formed, the corrosion resistance of the magnetic recording medium is prone to becoming insufficient. Therefore, a lubricating layer with a high degree of corrosion inhibition is required for the magnetic recording medium.

[0019] The present invention was made in view of the above circumstances, and its object is to provide a fluorinated ether compound suitable as a material for a lubricant for a magnetic recording medium that can form a lubricating layer with high corrosion inhibition effect.

[0020] Furthermore, 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 high corrosion inhibition effect for magnetic recording media.

[0021] Furthermore, the object of the present invention is to provide a magnetic recording medium having excellent corrosion resistance by providing a lubricating layer comprising the fluorinated ether compound of the present invention.

[0022] Methods for solving problems

[0023] That is, the present invention relates to the following matters.

[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 -CH2-R 2 -CH2-R 3 -CH2-R 4 -CH2-R 5 -CH2-R 6 -CH2-R 7 (1)

[0027] (In equation (1), R) 2 R 4 and R 6 For the same or different perfluoropolyether chains; R 3 R is the linking base shown in equation (2) below; 5 R is the linking base shown in equation (3) below; 1 and R 7 Each of these is an independent terminal group comprising two or three polar groups, each polar group being bonded to a different carbon atom, and the carbon atoms bonded to these polar groups being bonded to each other via a linker group containing a carbon atom of an unbonded polar group.

[0028]

[0029] (In equation (2), a is an integer from 1 to 3, and b is an integer from 1 to 2; in equation (3), c is an integer from 1 to 3, and d is an integer from 1 to 2; wherein, a in equation (2) and c in equation (3) are not both 1.)

[0030] The fluorinated ether compound of the first aspect of the present invention preferably has the features described below [2] to [8]. It is also preferable that any combination of two or more of the features described below [2] to [8] is also preferred.

[0031] [2] According to the fluorinated ether compound described in [1], a in the above formula (2) is an integer of 2 to 3, and c in the above formula (3) is an integer of 2 to 3.

[0032] [3] According to the fluorinated ether compound described in [1] or [2], in the above formula (1), R 1 and R 7 All of its polar groups are hydroxyl groups.

[0033] [4] The fluorinated ether compound according to any one of [1] to [3], in the above formula (1), -R 1 and -R 7 Each is an independent terminal base as shown in equations (4-1) to (4-5) below.

[0034]

[0035] (In equation (4-1), e is an integer from 0 to 1, and f is an integer from 1 to 4.)

[0036] (In equation (4-2), g is an integer from 1 to 2, and h is an integer from 1 to 3.)

[0037] (In equation (4-3), i is an integer from 1 to 3.)

[0038] (In equation (4-4), j is an integer from 1 to 2.)

[0039] [5] According to any one of [1] to [4], R in the above formula (1) 2 R 4 R 6 Each is independently any one of the following formulas (5) to (9).

[0040] -CF₂O-(CF₂CF₂O) k -(CF2O) l -CF2-(5)

[0041] (In equation (5), k and l represent the average degree of polymerization, each ranging from 0.1 to 20.)

[0042] -CF₂O-(CF₂CF₂O) m -CF2-(6)

[0043] (In equation (6), m represents the average degree of polymerization, which ranges from 0.1 to 20.)

[0044] -CF2CF2O-(CF2CF2CF2O) n -CF2CF2-(7)

[0045] (In equation (7), n represents the average degree of polymerization, ranging from 0.1 to 20.)

[0046] -CF2CF2CF2O-(CF2CF2CF2CF2O) o -CF2CF2CF2-(8)

[0047] (In equation (8), o represents the average degree of polymerization, which ranges from 0.1 to 10.)

[0048] -CF(CF3)O-(CF2CF(CF3)O) p -CF(CF3)-(9)

[0049] (In equation (9), p represents the average degree of polymerization, ranging from 0.1 to 20.)

[0050] [6] According to any one of [1] to [5], in the above formula (1), R 1 With R 7 same.

[0051] [7] According to any one of [1] to [6], in the above formula (1), R 2 With R 6 same.

[0052] [8] The fluorinated ether compound according to any one of [1] to [7] has a number-average molecular weight in the range of 500 to 10,000.

[0053] A second aspect of the present invention provides a lubricant for magnetic recording media.

[0054] [9] A lubricant for magnetic recording media, characterized in that it comprises any one of [1] to [8] a fluorinated ether compound.

[0055] The third aspect of the present invention provides the following magnetic recording medium.

[0056]

[10] A magnetic recording medium, characterized in that it is a magnetic recording medium on a substrate having at least a magnetic layer, a protective layer, and a lubricating layer disposed sequentially.

[0057] The above-mentioned lubricating layer contains any one of the fluorinated ether compounds described in [1] to [8].

[0058] The magnetic recording medium of the third aspect of the present invention preferably has the features described in

[11] .

[0059]

[11] According to the magnetic recording medium described in

[10] , the average film thickness of the above-mentioned lubricating layer is 0.5 nm to 2.0 nm.

[0060] The effects of the invention

[0061] Since the fluorinated ether compound of the present invention is a compound represented by the above formula (1), it can be used as a material for a lubricant for a magnetic recording medium that can form a lubricating layer with high corrosion inhibition effect.

[0062] The lubricant for magnetic recording media of the present invention contains the fluorinated ether compound of the present invention, and therefore can form a lubricating layer with high corrosion inhibition effect on the magnetic recording medium.

[0063] The magnetic recording medium of the present invention exhibits excellent corrosion resistance due to the presence of a lubricating layer containing the fluorinated ether compound of the present invention. Therefore, the magnetic recording medium of the present invention possesses excellent reliability and durability. Furthermore, because the magnetic recording medium of the present invention has a lubricating layer with high corrosion inhibition effect, the thickness of the protective layer and / or lubricating layer can be thin. Attached Figure Description

[0064] Figure 1 A schematic cross-sectional view illustrating an example of an embodiment of the magnetic recording medium of the present invention. Detailed Implementation

[0065] In order to solve the above-mentioned problems, the inventors have repeatedly conducted in-depth research focusing on the chain skeleton and terminal groups of fluorinated ether compounds.

[0066] As a result, it was discovered that as long as a chain-like skeleton with three perfluoropolyether chains bonded by two specific linking groups consisting of a chain structure composed of methylene (-CH2-) and ether bonds (-O-) is prepared, and specific terminal groups containing two or three polar groups are bonded at both ends of the chain-like skeleton via methylene, it is possible to obtain a fluorinated ether compound.

[0067] For the aforementioned fluorinated ether compounds with a chain-like backbone, one or both of the two linking groups have a methylene chain with 2 or 3 carbon atoms between the central perfluoropolyether chain and the carbon atom bound to the hydroxyl group. Therefore, it is presumed that the lubricating layer containing the aforementioned fluorinated ether compound with a chain-like backbone has suitable hydrophobicity.

[0068] Furthermore, if a lubricating layer containing the aforementioned fluorinated ether compound with a chain-like backbone is formed on the protective layer, the two ends of the perfluoropolyether chain disposed at the center of the chain-like backbone are tightly bonded to the protective layer through the hydroxyl groups of the linking groups disposed between the perfluoropolyether chains. Therefore, compared with the case of a fluorinated ether compound containing one or two perfluoropolyether chains with the same number of carbon atoms as the aforementioned chain-like backbone, the lubricant containing the aforementioned fluorinated ether compound with a chain-like backbone is easier to wet and spread on the protective layer, can uniformly bond to the protective layer, and can form a lubricating layer with high coverage and good adhesion.

[0069] Furthermore, each end of the aforementioned chain-like framework is independently configured with two or three polar groups, each polar group being bonded to a different carbon atom. The carbon atoms bonded to these polar groups are linked to each other via linking groups containing carbon atoms without polar groups. The two or three polar groups in these end groups differ from those where the carbon atoms bonded to the polar groups are bonded to each other, allowing for an orientation that enables tight adhesion to the protective layer. Therefore, for example, compared to a lubricating layer containing fluorinated ether compounds with end groups where carbon atoms bonded to polar groups are bonded to each other, a lubricating layer with high coverage and good adhesion can be formed. Furthermore, since the end groups have linking groups containing carbon atoms without polar groups, the hydrophobicity is improved compared to a lubricating layer containing fluorinated ether compounds with end groups where carbon atoms bonded to polar groups are bonded to each other.

[0070] Thus, the lubricating layer containing the fluorinated ether compound with the specific end groups bonded to both ends of the aforementioned chain-like backbone exhibits suitable hydrophobicity and good adhesion to the protective layer. Therefore, it is presumed that the magnetic recording medium of the aforementioned lubricating layer has a high corrosion inhibition effect.

[0071] The inventors conducted further and repeated studies and confirmed that forming a lubricating layer containing the above-mentioned fluorinated ether compound on the protective layer resulted in a high corrosion inhibition effect on the magnetic recording medium, which led to the invention.

[0072] The following describes in detail preferred examples of the fluorinated ether compound, the lubricant for magnetic recording media (hereinafter sometimes abbreviated as "lubricant"), and the magnetic recording media of the present invention. Furthermore, the present invention is not limited to the embodiments shown below. Without departing from the spirit of the present invention, additions, omissions, substitutions, and modifications can be made regarding numbers, quantities, positions, ratios, materials, structures, etc.

[0073] [Fluoroether compounds]

[0074] The fluorinated ether compound in this embodiment is represented by the following formula (1).

[0075] R 1 -CH2-R 2 -CH2-R 3 -CH2-R 4 -CH2-R 5 -CH2-R 6 -CH2-R 7 (1)

[0076] (In equation (1), R) 2 R 4 and R 6 For the same or different perfluoropolyether chains; R 3 R is the linking base shown in equation (2) below; 5 R is the linking base shown in equation (3) below; 1 and R 7 Each polar group independently comprises two or three polar groups, each polar group being bonded to a different carbon atom. The carbon atoms bonded to these polar groups are linked to each other via linking groups containing carbon atoms of unbonded polar groups.

[0077]

[0078] (In equation (2), a is an integer from 1 to 3, and b is an integer from 1 to 2; in equation (3), c is an integer from 1 to 3, and d is an integer from 1 to 2; wherein, a in equation (2) and c in equation (3) are not both 1.)

[0079] (R 1 and R 7 )

[0080] In the fluorinated ether compound shown in formula (1) above, R 1 and R 7 Each polar group is independently composed of two or three polar groups, each polar group being bonded to a different carbon atom. The carbon atoms bonded to the polar groups are bonded to each other via linking groups containing carbon atoms that are not bonded to polar groups.

[0081] For the fluorinated ether compound shown in formula (1), R 1 and R 7 Each has two or three polar groups. Therefore, when a lubricating layer is formed on the protective layer using a lubricant containing it, a suitable interaction occurs between the lubricating layer and the protective layer.

[0082] Examples of polar groups include, for example, hydroxyl (-OH), amino (-NH2), carboxyl (-COOH), aldehyde (-COH), carbonyl (-CO-), and sulfonyl (-SO3H). 1 and / or R 7 Preferably, it contains a hydroxyl group as a polar group, more preferably R 1 and R 7 All the polar groups it contains are hydroxyl groups. If it is R... 1 and / or R 7 Fluorinated ether compounds containing hydroxyl groups, when used with lubricants containing them to form a lubricating layer on the protective layer, create a more suitable interaction between the lubricating layer and the protective layer.

[0083] In the fluorinated ether compound shown in formula (1), R 1 The polar groups contained therein, and R 7 The total number of polar groups contained is 4 to 6. Since the total number is 4 or more, the adhesion (seamlessness) between the lubricating layer and the protective layer containing the fluorinated ether compound is high. Furthermore, since the total number is 6 or less, in magnetic recording media having a lubricating layer containing the fluorinated ether compound, it is possible to prevent the fluorinated ether compound from being too polar and adhering to the magnetic head as foreign matter (stains) during pickup.

[0084] R 1 The number of polar bases contained therein, and R 7 The number of polar bases included is preferably the same. That is, R is preferred. 1 and R 7 Each contains two polar groups, or R 1 and R 7 Each contains three polar groups. In this case, because the lubricant containing the fluorinated ether compound adheres well to the protective layer, it achieves a high coverage rate and easily yields a lubricating layer with high corrosion inhibition effect on the magnetic recording medium. In particular, in R... 1 and R 7 When each compound contains three polar groups, the polar groups contained in the fluorinated ether compound are firmly bonded to the protective layer, resulting in a higher coverage rate and a higher corrosion inhibition effect on the magnetic recording medium.

[0085] R 1 and R 7 Each of the contained polar groups is bonded to a different carbon atom. In R1 and R 7 In this compound, the carbon atoms bonded by the polar groups are bonded to each other via linking groups containing carbon atoms without polar groups. Therefore, the fluorinated ether compound shown in formula (1) exhibits better hydrophobicity than, for example, compounds with terminal groups in which the carbon atoms bonded by the polar groups are bonded to each other. Thus, it is presumed that a lubricating layer containing the fluorinated ether compound shown in formula (1) can prevent water intrusion and effectively suppress corrosion of the magnetic recording medium.

[0086] Furthermore, when the carbon atoms bonded to the polar groups are bonded to each other via linking groups containing carbon atoms without polar groups, the orientation of the terminal polar group (the linking group containing carbon atoms without polar groups) and the polar group adjacent to the terminal polar group can achieve a close fit with the protective layer. Therefore, it is presumed that when the carbon atoms bonded to the polar groups are bonded to each other via linking groups containing carbon atoms without polar groups, a lubricating layer with high corrosion inhibition effect on the magnetic recording medium can be obtained.

[0087] In contrast, when the fluorinated ether compound contained in the lubricating layer has a terminal polar group (terminal polar group) bonded to a carbon atom, and a terminal group bonded to a carbon atom bonded to an adjacent polar group, either the terminal polar group or the adjacent polar group is oriented in the opposite direction relative to the protective layer. Therefore, either the terminal polar group or the adjacent polar group is not easily bonded to the protective layer, resulting in poor adhesion between the lubricating layer and the protective layer.

[0088] In R 1 and R 7 In the case where the carbon atom bonded to the terminal polar group and the linking group between the carbon atom bonded to the carbon atom bonded to the polar group adjacent to the terminal polar group contain oxygen atoms (for example, in the case of terminal groups shown in formulas (4-2), (4-3), and (4-4) below), R 1 and R 7 The aforementioned linker preferably has a linear structure comprising 2 to 5 carbon atoms containing an unbonded polar group. Even when the linker contains oxygen atoms, a linear structure comprising 2 or more carbon atoms containing an unbonded polar group results in a fluorinated ether compound with good hydrophobicity. Furthermore, when the linker has a linear structure comprising 5 or fewer carbon atoms, the hydrophobicity of the linker is not excessively high, thus avoiding obstacles to adhesion to the protective layer. In particular, in R... 1 and R 7 With each of the three polar groups present, a lubricating layer with superior adhesion to the protective layer can be formed. Therefore, containing R 1 and R 7The fluorinated ether compound, which has a linear structure containing carbon atoms within the aforementioned range as its linking group, exhibits excellent adhesion between the lubricating and protective layers. Furthermore, by possessing appropriate hydrophobicity, it can prevent water intrusion and provides high corrosion inhibition of the magnetic recording medium.

[0089] Furthermore, in R 1 and R 7 When the aforementioned linker group contains oxygen atoms, the linker group preferably has a linear chain structure consisting of 3 to 9 atoms, and more preferably a linear chain structure consisting of 3 to 6 atoms. If the number of atoms contained in the linker group is within the aforementioned range, the molecular mobility is appropriate, and intramolecular aggregation is less likely to occur. Therefore, it becomes a fluorinated ether compound that can form a lubricating layer with better adhesion to the protective layer.

[0090] In R 1 and R 7 In the case where the linking group between the carbon atom bonded to the terminal polar group and the carbon atom bonded to the polar group adjacent to the terminal polar group does not contain an oxygen atom (for example, in the case of the terminal group shown in formulas (4-1) and (4-5) below), in R 1 and R 7 In the case where the number of polar groups is 2 or 3, the linker preferably has a linear structure containing 1 to 4 carbon atoms of unbonded polar groups. When the linker has a linear structure containing 1 or more carbon atoms of unbonded polar groups but without oxygen atoms, it becomes a fluorinated ether compound with good hydrophobicity. Furthermore, when the linker has a linear structure containing 4 or fewer carbon atoms, the hydrophobicity of the linker is not too high, thus not hindering adhesion to the protective layer. Moreover, since the linker between the carbon atom bonded to the terminal polar group and the carbon atom bonded to the adjacent polar group does not contain oxygen atoms, intramolecular interactions are small, and intramolecular aggregation is less likely to occur. Therefore, it becomes a fluorinated ether compound that can form a lubricating layer with even better adhesion to the protective layer. As a result, containing R... 1 and R 7 The fluorinated ether compound, which has a linear structure containing carbon atoms within the aforementioned range as its linking group, exhibits excellent adhesion between the lubricating and protective layers. Furthermore, by possessing appropriate hydrophobicity, it can prevent water intrusion and provides high corrosion inhibition of the magnetic recording medium.

[0091] In the fluorinated ether compound shown in formula (1), R 1 With R 7 They can be the same or different, but being the same is preferred. If R 1 With R 7Similarly, it becomes a fluorinated ether compound that easily and uniformly wets and spreads on the protective layer, readily yielding a lubricating layer with a uniform film thickness. As a result, the lubricating layer containing this fluorinated ether compound has good coverage and is preferred. Furthermore, in R... 1 With R 7 Under the same circumstances, with R 1 With R 7 Compared to other methods, fluorinated ether compounds can be manufactured more efficiently with fewer manufacturing steps.

[0092] In the fluorinated ether compounds shown in formula (1), -R is preferred. 1 and -R 7 Each is an independent terminal base as shown in any of the following equations (4-1) to (4-5). In -R 1 and -R 7 In the case of the terminal base shown in any of equations (4-1) to (4-5), -R 1 and -R 7 Containing two or three hydroxyl groups, the linking group between the carbon atom bonded to the terminal hydroxyl group and the carbon atom bonded to the adjacent hydroxyl group has a straight-chain structure containing an appropriate number of carbon atoms. Therefore, in -R 1 and -R 7 When the terminal group is as shown in formulas (4-1) to (4-5), it becomes a fluorinated ether compound with suitable hydrophobicity.

[0093] Furthermore, in -R 1 and -R 7 When the terminal group is any one of the following formulas (4-1), (4-2), (4-4), or (4-5), and contains three hydroxyl groups, the carbon atom bonded to the hydroxyl group disposed on the side of the perfluoropolyether chain, and the linking group between the carbon atom bonded to the adjacent hydroxyl group, also have a straight-chain structure containing an appropriate number of carbon atoms. Therefore, this results in a fluoroether compound that can form a lubricating layer with superior adhesion to the protective layer, appropriate hydrophobicity, and high corrosion inhibition effect on the magnetic recording medium.

[0094]

[0095] (In equation (4-1), e is an integer from 0 to 1, and f is an integer from 1 to 4.)

[0096] (In equation (4-2), g is an integer from 1 to 2, and h is an integer from 1 to 3.)

[0097] (In equation (4-3), i is an integer from 1 to 3.)

[0098] (In equation (4-4), j is an integer from 1 to 2.)

[0099] In the terminal groups shown in Formula (4-1), e is an integer from 0 to 1, and f is an integer from 1 to 4. Regarding the terminal groups shown in Formula (4-1), the linking group between the carbon atom bonded to the terminal hydroxyl group and the carbon atom bonded to the adjacent hydroxyl group does not contain oxygen atoms. Therefore, it exhibits appropriate hydrophobicity. Furthermore, since f is 4 or less, the hydrophobicity of the linking group is not too high, thus not hindering the adhesion to the protective layer, resulting in excellent corrosion suppression of the magnetic recording medium. Further, since the linking group between the carbon atom bonded to the terminal hydroxyl group and the carbon atom bonded to the adjacent hydroxyl group does not contain oxygen atoms, the intramolecular interactions between the hydroxyl groups contained in the terminal groups are small. Therefore, intramolecular aggregation is less likely to occur, and a lubricating layer with even better adhesion to the protective layer can be formed. Moreover, when e is 1, since the terminal group shown in Formula (4-1) contains 3 hydroxyl groups, it exhibits even better adhesion to the protective layer.

[0100] In the terminal groups shown in Formula (4-2), g is an integer from 1 to 2, and h is an integer from 1 to 3. Therefore, fluorinated ether compounds with terminal groups shown in Formula (4-2) exhibit good hydrophobicity and show excellent corrosion suppression effects for magnetic recording media. Regarding the terminal groups shown in Formula (4-2), the linking group between the carbon atom bonded to the terminal hydroxyl group and the carbon atom bonded to the adjacent hydroxyl group contains an oxygen atom. Since h is 1 to 3 in the terminal groups shown in Formula (4-2), the molecular mobility is appropriate. Therefore, intramolecular aggregation of the hydroxyl groups contained in the terminal groups is less likely to occur, resulting in better adhesion to the protective layer. Furthermore, when g is 2, since the terminal groups shown in Formula (4-2) contain 3 hydroxyl groups, they exhibit even better adhesion to the protective layer.

[0101] In the terminal groups shown in formula (4-3), i is an integer from 1 to 3. Therefore, fluorinated ether compounds containing the terminal groups shown in formula (4-3) exhibit good hydrophobicity and demonstrate excellent corrosion suppression effects on magnetic recording media. Regarding the terminal groups shown in formula (4-3), the linking group between the carbon atom bonded to the terminal hydroxyl group and the carbon atom bonded to the hydroxyl group adjacent to the terminal hydroxyl group contains an oxygen atom. Since i is 1 to 3 in the terminal groups shown in formula (4-3), the molecular mobility is appropriate. Therefore, intramolecular aggregation of the hydroxyl groups contained in the terminal groups is less likely to occur, resulting in better adhesion to the protective layer.

[0102] In the terminal groups shown in formula (4-4), j is an integer from 1 to 2. Therefore, fluorinated ether compounds containing the terminal groups shown in formula (4-4) exhibit good hydrophobicity and demonstrate excellent corrosion suppression effects on magnetic recording media. The terminal groups shown in formula (4-4), containing three hydroxyl groups, exhibit excellent adhesion to the protective layer.

[0103] The terminal groups shown in Formula (4-5) exhibit good hydrophobicity because the carbon atom bonded to the terminal hydroxyl group and the linking group between the carbon atom bonded to the adjacent hydroxyl group do not contain oxygen atoms. Therefore, lubricating layers containing fluorinated ether compounds with terminal groups shown in Formula (4-5) exhibit excellent corrosion suppression effects on magnetic recording media. Furthermore, the terminal groups shown in Formula (4-5), containing three hydroxyl groups, exhibit excellent adhesion to the protective layer.

[0104] (R 3 and R 5 )

[0105] In the fluorinated ether compound shown in formula (1), R 3 The linker is shown in equation (2) below. The rightmost oxygen atom in parentheses in equation (2) of the linker shown in equation (2) is connected to R. 4 Adjacent methylene groups (-CH2-) are bonded. Furthermore, in the fluorinated ether compounds shown in formula (1), R... 5 The linker is shown in equation (3) below. The leftmost oxygen atom in equation (3), enclosed in parentheses, in the linker shown in equation (3) is connected to R. 4 Adjacent methylene groups (-CH2-) bind together.

[0106]

[0107] (In equation (2), a is an integer from 1 to 3, and b is an integer from 1 to 2; in equation (3), c is an integer from 1 to 3, and d is an integer from 1 to 2; wherein, a in equation (2) and c in equation (3) are not both 1.)

[0108] In equation (2), 'a' is an integer from 1 to 3, and in equation (3), 'c' is an integer from 1 to 3. 'a' in equation (2) and 'c' in equation (3) are not both 1. That is, at least one of 'a' and 'c' is an integer from 2 to 3. Therefore, the fluorinated ether compound shown in equation (1) and the compound representing R... 3 In equation (2), a is 1 and represents R. 5 Compared to compounds with c=1 in formula (3), R 3 and / or R 5 The linkage group shown contains a large number of carbon atoms, resulting in better hydrophobicity.

[0109] For the fluorinated ether compound shown in formula (1), it is preferable that a in formula (2) is an integer from 2 to 3, and c in formula (3) is an integer from 2 to 3. In this case, the hydrophobicity of the fluorinated ether compound shown in formula (1) becomes better, and the lubricating layer containing it exhibits a superior corrosion inhibition effect on the magnetic recording medium.

[0110] In formula (2), b is an integer from 1 to 2, and in formula (3), d is an integer from 1 to 2. The hydroxyl groups in formulas (2) and (3) improve the adhesion to the protective layer in the lubricating layer containing the fluorinated ether compound. In order to make the fluorinated ether compound easy to synthesize, b in formula (2) and d in formula (3) are preferably 1.

[0111] The R of the fluorinated ether compound shown in formula (1) 3 R is the linking base shown in equation (2). 5 The linking base is shown in equation (3). Therefore, it is configured in R 3 and R 5 The oxygen atoms at both ends are respectively disposed in R 3 and R 5 The methylene groups (-CH2-) on both sides of the compound combine to form ether bonds (-O-). The four ether bonds formed in this way impart a suitable degree of flexibility to the fluorinated ether compound shown in formula (1), making R... 3 and R 5 The affinity of the hydroxyl groups to the protective layer increases.

[0112] (R 2 R 4 R 6 )

[0113] In the fluorinated ether compound shown in formula (1), R 2 R 4 R 6 These can be the same or different perfluoropolyether (PFPE) chains. R 2 R 4 R 6 When the PFPE chains shown form a lubricating layer by coating a lubricant containing the fluorinated ether compound of this embodiment onto a protective layer, the surface of the protective layer is coated with lubricant, thereby reducing the friction between the magnetic head and the protective layer. Furthermore, the PFPE chains, through their low surface energy, impart water resistance to the lubricating layer containing the fluorinated ether compound of this embodiment, thus improving the corrosion resistance of the magnetic recording medium to which the lubricating layer is provided.

[0114] R 2 R 4 R 6 Any PFPE chain is acceptable, and the appropriate chain can be selected based on the performance requirements of the lubricant containing fluorinated ether compounds. Examples of PFPE chains include those formed from perfluoromethylene oxide polymers, perfluoroethyl oxide polymers, perfluoropropylene oxide polymers, perfluoroisopropylene oxide polymers, and copolymers thereof.

[0115] The PFPE chain can be, for example, a structure derived from a polymer or copolymer of perfluoroalkylene oxides, as shown in the following formula (Rf).

[0116] -(CF2) w1 O(CF2O) w2 (CF2CF2O) w3 (CF2CF2CF2O) w4 (CF2CF2CF2CF2O) w5 (CF2) w6 -(Rf)

[0117] (In equation (Rf), w2, w3, w4, and w5 represent the average degree of polymerization, each independently representing 0 to 20; where all of w2, w3, w4, and w5 are not simultaneously 0; w1 and w6 represent the average value of the number of -CF2-, each independently representing 1 to 3; there is no particular restriction on the order of repeating units in equation (Rf).)

[0118] In formula (Rf), w2, w3, w4, and w5 represent the average degree of polymerization, each independently representing 0 to 20, preferably 0 to 15, and more preferably 0 to 10.

[0119] In formula (Rf), w1 and w6 are the average values ​​of the numbers representing -CF2-, each independently representing 1 to 3. In the polymer shown in formula (Rf), w1 and w6 are determined based on the structure of the repeating units arranged at the ends of the chain structure, etc.

[0120] In equation (Rf), (CF2O), (CF2CF2O), (CF2CF2CF2O), and (CF2CF2CF2CF2O) are repeating units. There are no particular restrictions on the order of the repeating units in equation (Rf). Furthermore, there are no particular restrictions on the number of types of repeating units in equation (Rf).

[0121] R in equation (1) 2 R 4 R 6 Preferably, each is an independent PFPE chain, for example, as shown in the following formula (Rf-1).

[0122] -(CF2) w7 O-(CF2CF2O) w8 -(CF2CF2CF2O) w9 -(CF2) w10 -(Rf-1)

[0123] (In equation (Rf-1), w8 and w9 represent the average degree of polymerization, each independently representing 0.1 to 20; w7 and w10 represent the average value of the -CF2-, each independently representing 1 to 2.)

[0124] There is no particular restriction on the order of (CF2CF2O) and (CF2CF2CF2O) as repeating units in formula (Rf-1). 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 20, preferably 0.1 to 15, and more preferably 1 to 10. w7 and w10 in formula (Rf-1) are the average values ​​of the number representing -CF2-, and are each independently represented as 1 to 2. In the polymer shown in formula (Rf-1), w7 and w10 are determined according to the structure of the repeating units arranged at the ends of the chain structure, etc.

[0125] R in equation (1) 2 R 4 R 6 It is also preferred that each of the following formulas (5) to (9) be independent. In addition, there is no particular restriction on the order of (CF2CF2O) and (CF2O) as repeating units in formula (5). Formula (5) may include any of the following: random copolymers, block copolymers, and alternating copolymers composed of monomer units (CF2-CF2-O) and (CF2-O).

[0126] -CF₂O-(CF₂CF₂O) k -(CF2O) l -CF2-(5)

[0127] (In equation (5), k and l represent the average degree of polymerization, each ranging from 0.1 to 20.)

[0128] -CF₂O-(CF₂CF₂O) m -CF2-(6)

[0129] (In equation (6), m represents the average degree of polymerization, which ranges from 0.1 to 20.)

[0130] -CF2CF2O-(CF2CF2CF2O) n -CF2CF2-(7)

[0131] (In equation (7), n represents the average degree of polymerization, ranging from 0.1 to 20.)

[0132] -CF2CF2CF2O-(CF2CF2CF2CF2O) o -CF2CF2CF2-(8)

[0133] (In equation (8), o represents the average degree of polymerization, which ranges from 0.1 to 10.)

[0134] -CF(CF3)O-(CF2CF(CF3)O) p -CF(CF3)-(9)

[0135] (In equation (9), p represents the average degree of polymerization, ranging from 0.1 to 20.)

[0136] In equation (5), k and l, representing the average degree of polymerization, are 0.1 to 20; in equation (6), m, representing the average degree of polymerization, is 0.1 to 20; in equation (7), n, representing the average degree of polymerization, is 0.1 to 20; in equation (8), o, representing the average degree of polymerization, is 0.1 to 10; and in equation (9), p, representing the average degree of polymerization, is 0.1 to 20. k, l, m, n, o, and p can be arbitrarily selected within the above ranges. If k, l, m, n, o, and p are all 0.1 or higher, a fluorinated ether compound is obtained that can better suppress corrosion of the magnetic recording medium. Furthermore, if k, l, m, n, and p are all 20 or lower, and o is 10 or lower, the viscosity of the fluorinated ether compound will not become too high, and the lubricant containing it is easy to apply, which is preferred. In order to make the fluorinated ether compound easy to wet and spread on the protective layer and easy to obtain a lubricating layer with uniform film thickness, the average degree of polymerization k, l, m, n, o, and p are preferably 1 to 10, more preferably 2 to 8. In addition, k, l, m, n, o, and p can be, for example, 0.5 to 9, 1 to 8, 2 to 7, 3 to 6, 4 to 5, etc.

[0137] In equation (1) R 2 R 4 R 6 In the case of any of formulas (5) to (9), the synthesis of fluorinated ether compounds is easy and preferred. In R 2 R 4 R 6 In the case of any of Equations (5) to (7), it is more preferred because the raw materials are readily available.

[0138] Furthermore, in R 2 R 4 R 6 In the case of any of formulas (5) to (9), 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, a fluorinated ether compound with moderate hardness is obtained. As a result, the fluorinated ether compound coated on the protective layer is not easily aggregated on the protective layer, and a thinner lubricating layer can be formed with sufficient coverage.

[0139] In the fluorinated ether compound shown in formula (1), R 2 R 4 R6 The PFPE chains shown can be all identical, each different, or only partially identical. Furthermore, in this embodiment, "identical PFPE chains" also includes cases where the PFPE chains have the same structure (repeating units) but different average degrees of polymerization.

[0140] In the fluorinated ether compounds shown in formula (1), R is preferred to facilitate synthesis. 2 With R 6 Same. In R 2 With R 6 Under the same conditions, R is preferred. 3 With R 5 The same applies, and R 1 With R 7 Similarly, such fluorinated ether compounds can be easily and efficiently manufactured with few processing steps. Furthermore, the term R in this specification... 3 With R 5 Same, refers to the perfluoropolyether chain (R) disposed at the center of the fluoroether compound shown in formula (1). 4 ), R 3 The atoms contained and R 5 The atoms contained are arranged symmetrically. That is, a in equation (2) is the same as c in equation (3), and b in equation (2) is the same as d in equation (3).

[0141] The fluorinated ether compound represented by formula (1) is preferably any of the compounds represented by formulas (A) to (T) below.

[0142] In addition, ra, qb, sc, tc, rd, qe, qf, sg, tg, rh, qi, sj, tj, qk, rk, sl, tl, rl, qm, rm, qn, rn, qo, ro, qp, sp, tp, qq, sq, tq, sr, tr, rr, qs, ss, ts, st, tt, and rt in equations (A) to (T) are values ​​representing the average degree of polymerization, and therefore are not necessarily integers.

[0143] The compounds represented by formulas (A) to (T) below all have R 1 With R 7 same.

[0144] The compounds represented by formulas (A) to (J) below all have R 2 With R 4 With R 6 The same. All compounds represented by formulas (K) to (T) below are R. 2 With R 6 same.

[0145] The compounds represented by the following formulas (A)~(G), (K), (L), (N)~(P), (R), (S) all have R 3 With R 5 Similarly, in equation (2), a is 2 and b is 1, and in equation (3), c is 2 and d is 1.

[0146] The compounds represented by the following formulas (H) to (J), (M), (Q), and (T) all have R. 3 With R 5 Similarly, in equation (2), a is 3 and b is 1, and in equation (3), c is 3 and d is 1.

[0147] The R of the compound shown in formula (A) below 1 and R 7 The terminal base is shown in equation (4-2), where g is 1, h is 2, and R is 1. 2 and R 4 and R 6 The PFPE chain is shown in equation (6).

[0148] The R of the compound shown in formula (B) below 1 and R 7 The terminal base is shown in equation (4-2), where g is 2, h is 2, and R is 2. 2 and R 4 and R 6 The PFPE chain is shown in equation (7).

[0149] The R of the compound shown in formula (C) below 1 and R 7 The terminal base is shown in equation (4-1), where e is 0, f is 1, and R... 2 and R 4 and R 6 The PFPE chain is shown in equation (5).

[0150] The R of the compound shown in formula (D) below 1 and R 7 R is the terminal base shown in equation (4-5). 2 and R 4 and R 6 The PFPE chain is shown in equation (6).

[0151] The R of the compound shown in formula (E) below 1 and R 7 The terminal base is shown in equation (4-2), where g = 1, h = 1, and R = 1. 2 and R 4 and R 6 The PFPE chain is shown in equation (7).

[0152] The R of the compound shown in formula (F) below 1 and R 7 The terminal base is shown in equation (4-3), where i is 1 and R is 1. 2 and R 4 and R 6 The PFPE chain is shown in equation (7).

[0153] The R of the compound represented by the following formula (G) 1 and R 7 The terminal base is shown in equation (4-1), where e is 1, f is 1, and R is 1. 2 and R 4 and R 6 The PFPE chain is shown in equation (5).

[0154] The R of the compound represented by the following formula (H) 1 and R 7 The terminal base is shown in equation (4-1), where e is 0, f is 2, and R... 2 and R 4 and R 6 The PFPE chain is shown in equation (6).

[0155] The R of the compound shown in formula (I) below 1 and R 7 The terminal base is shown in equation (4-4), where j is 2 and R is 2. 2 and R 4 and R 6 The PFPE chain is shown in equation (7).

[0156] The R of the compound represented by the following formula (J) 1 and R 7 The terminal base is shown in equation (4-2), where g is 2, h is 1, and R is 1. 2 and R 4 and R 6 The PFPE chain is shown in equation (5).

[0157] The R of the compound represented by the following formula (K) 1 and R 7 The terminal base is shown in equation (4-1), where e is 1, f is 1, and R is 1. 2 and R 6 For the PFPE chain shown in equation (7), R 4 The PFPE chain is shown in equation (6).

[0158] The R of the compound represented by the following formula (L) 1 and R 7The terminal base is shown in equation (4-4), where j is 1 and R is 1. 2 and R 6 For the PFPE chain shown in equation (5), R 4 The PFPE chain is shown in equation (6).

[0159] The R of the compound represented by the following formula (M) 1 and R 7 The terminal base is shown in equation (4-2), where g is 1, h is 2, and R is 1. 2 and R 6 For the PFPE chain shown in equation (7), R 4 The PFPE chain is shown in equation (6).

[0160] The R of the compound represented by the following formula (N) 1 and R 7 The terminal base is shown in equation (4-2), where g is 2, h is 2, and R is 2. 2 and R 6 For the PFPE chain shown in equation (6), R 4 The PFPE chain is shown in equation (7).

[0161] The R of the compound represented by the following formula (O) 1 and R 7 R is the terminal base shown in equation (4-5). 2 and R 6 For the PFPE chain shown in equation (6), R 4 The PFPE chain is shown in equation (7).

[0162] The R of the compound represented by the following formula (P) 1 and R 7 The terminal base is shown in equation (4-2), where g is 1, h is 3, and R is 1. 2 and R 6 For the PFPE chain shown in equation (5), R 4 The PFPE chain is shown in equation (7).

[0163] The R of the compound represented by the following formula (Q) 1 and R 7 The terminal base is shown in equation (4-2), where g = 1, h = 1, and R = 1. 2 and R 6 For the PFPE chain shown in equation (5), R 4 The PFPE chain is shown in equation (7).

[0164] The R of the compound represented by the following formula (R) 1 and R 7The terminal base is shown in equation (4-2), where g is 2, h is 1, and R is 1. 2 and R 6 For the PFPE chain shown in equation (6), R 4 The PFPE chain is shown in equation (5).

[0165] The R of the compound represented by the following formula (S) 1 and R 7 The terminal base is shown in equation (4-1), where e is 0, f is 3, and R... 2 and R 6 For the PFPE chain shown in equation (7), R 4 The PFPE chain is shown in equation (5).

[0166] The R of the compound represented by the following formula (T) 1 and R 7 The terminal base is shown in equation (4-1), where e is 1, f is 2, and R... 2 and R 6 For the PFPE chain shown in equation (6), R 4 The PFPE chain is shown in equation (5).

[0167]

[0168] (In formula (A), Fpa1 and Fpa2 are represented by formula (AF). In Fpa1 and Fpa2, ra represents the average degree of polymerization, ranging from 0.1 to 20. The ra in Fpa1 and Fpa2 can be the same or different.)

[0169] (In equation (B), Fdb1 and Fdb2 are represented by equation (BF). In Fdb1 and Fdb2, qb represents the average degree of polymerization, ranging from 0.1 to 20. The qb in Fdb1 and the qb in Fdb2 can be the same or different.)

[0170]

[0171] (In equation (C), Ffc1 and Ffc2 are represented by equation (CF). sc and tc in Ffc1 and Ffc2 represent the average degree of polymerization, ranging from 0.1 to 20. The sc and tc in Ffc1 and Ffc2 can be the same or different.)

[0172] (In equation (D), Fpd1 and Fpd2 are represented by equation (DF). In Fpd1 and Fpd2, rd represents the average degree of polymerization, ranging from 0.1 to 20. The rd in Fpd1 and the rd in Fpd2 can be the same or different.)

[0173]

[0174] (In equation (E), Fde1 and Fde2 are represented by equation (EF). In Fde1 and Fde2, qe represents the average degree of polymerization, ranging from 0.1 to 20. The qe in Fde1 and the qe in Fde2 can be the same or different.)

[0175] (In equation (F), Fdf1 and Fdf2 are represented by equation (FF). In Fdf1 and Fdf2, qf represents the average degree of polymerization, ranging from 0.1 to 20. The qf in Fdf1 and the qf in Fdf2 can be the same or different.)

[0176]

[0177] (In formula (G), Ffg1 and Ffg2 are represented by formula (GF). sg and tg in Ffg1 and Ffg2 represent the average degree of polymerization, ranging from 0.1 to 20. The sg and tg values ​​in Ffg1 and Ffg2 can be the same or different.)

[0178] (In formula (H), Fph1 and Fph2 are represented by formula (HF). In Fph1 and Fph2, rh represents the average degree of polymerization, ranging from 0.1 to 20. The rh in Fph1 and the rh in Fph2 can be the same or different.)

[0179]

[0180] (In equation (I), Fdi1 and Fdi2 are represented by equation (IF). In Fdi1 and Fdi2, qi represents the average degree of polymerization, ranging from 0.1 to 20. The qi in Fdi1 and the qi in Fdi2 can be the same or different.)

[0181] (In equation (J), Ffj1 and Ffj2 are represented by equation (JF). sj and tj in Ffj1 and Ffj2 represent the average degree of polymerization, ranging from 0.1 to 20. sj and tj in Ffj1 and Ffj2 can be the same or different.)

[0182]

[0183] (In equation (K), Fdk1 and Fpk1 are represented by equation (KF). In Fdk1, qk represents the average degree of polymerization, ranging from 0.1 to 20. In Fpk1, rk represents the average degree of polymerization, ranging from 0.1 to 20.)

[0184] (In formula (L), Ffl1 and Fpl1 are represented by formula (LF). In Ffl1, sl and tl represent the average degree of polymerization, ranging from 0.1 to 20. In Fpl1, rl represents the average degree of polymerization, ranging from 0.1 to 20.)

[0185]

[0186] (In formula (M), Fdm1 and Fpm1 are represented by formula (MF). In Fdm1, qm represents the average degree of polymerization, ranging from 0.1 to 20. In Fpm1, rm represents the average degree of polymerization, ranging from 0.1 to 20.)

[0187] (In equation (N), Fdn1 and Fpn1 are represented by equation (NF). In Fdn1, qn represents the average degree of polymerization, ranging from 0.1 to 20. In Fpn1, rn represents the average degree of polymerization, ranging from 0.1 to 20.)

[0188]

[0189] (In equation (O), Fdo1 and Fpo1 are represented by equation (OF). In Fdo1, qo represents the average degree of polymerization, ranging from 0.1 to 20. In Fpo1, ro represents the average degree of polymerization, ranging from 0.1 to 20.)

[0190] (In equation (P), Fdp1 and Ffp1 are represented by equation (PF). In Fdp1, qp represents the average degree of polymerization, ranging from 0.1 to 20. In Ffp1, sp and tp represent the average degree of polymerization, ranging from 0.1 to 20.)

[0191]

[0192] (In equation (Q), Fdq1 and Ffq1 are represented by equation (QF). In Fdq1, qq represents the average degree of polymerization, ranging from 0.1 to 20. In Ffq1, sq and tq represent the average degree of polymerization, ranging from 0.1 to 20.)

[0193] (In equation (R), Ffr1 and Fpr1 are represented by equation (RF). In Ffr1, sr and tr represent the average degree of polymerization, ranging from 0.1 to 20. In Fpr1, rr represents the average degree of polymerization, ranging from 0.1 to 20.)

[0194]

[0195] (In equation (S), Fds1 and Ffs1 are represented by equation (SF). In Fds1, qs represents the average degree of polymerization, ranging from 0.1 to 20. In Ffs1, ss and ts represent the average degree of polymerization, ranging from 0.1 to 20.)

[0196] (In equation (T), Fft1 and Fpt1 are represented by equation (TF). In Fft1, st and tt represent the average degree of polymerization, ranging from 0.1 to 20. In Fpt1, rt represents the average degree of polymerization, ranging from 0.1 to 20.)

[0197] If the compound shown in formula (1) is any of the compounds shown in formulas (A) to (T) above, the raw materials are readily available and a lubricating layer that can suppress corrosion of the magnetic recording medium even if the thickness is thin is preferred.

[0198] If the compound shown in formula (1) is any one of the compounds shown in formulas (B), (D), (F) to (T), it can form a lubricating layer with particularly high corrosion inhibition effect on the magnetic recording medium, which is preferred.

[0199] The fluorinated ether compound in this embodiment preferably has a number-average molecular weight (Mn) 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 5,000. 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 adhering 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 the lubricant containing it. If the number-average molecular weight is 5,000 or lower, it becomes an easily operable viscosity when applied as a lubricant, and is therefore more preferred.

[0200] The number-average molecular weight (Mn) of the fluorinated ether compounds was determined by using AVANCE III 400 manufactured by Blu-ray Bio-Spin Co., Ltd. 1 H-NMR and 19 The value is determined by F-NMR. In NMR (nuclear magnetic resonance) determination, the sample is diluted with one or a mixture of solvents such as hexafluorobenzene, d-acetone, and d-tetrahydrofuran for determination. 19 The F-NMR chemical shift benchmark sets the peak of hexafluorobenzene at -164.7 ppm. 1 The baseline for H-NMR chemical shifts was set at 2.2 ppm for the peak of acetone.

[0201] "Manufacturing method"

[0202] 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.

[0203] In this embodiment, an example is the manufacture of a product having R 4The case of a compound with a symmetrical structure centered on the fluorinated ether compound shown in formula (1) will be used as an example. Specifically, the case of manufacturing R in formula (1) will be given. 2 R 4 R 6 The three PFPE chains shown have the same structure, R 1 With R 7 Same, R 3 With R 5 The same compound will be used as an example for illustration.

[0204] First, prepare R in equation (1) 4 The corresponding perfluoropolyether chain has fluorinated compounds with hydroxymethyl (-CH2OH) groups at both ends. Next, the hydroxyl groups of the hydroxymethyl groups at both ends of the fluorinated compounds are... 3 (=R 5 The reaction of halogen compounds with the corresponding epoxy group (first reaction) yields a compound that reacts with R. 4 The corresponding perfluoropolyether chain has R at both ends. 3 (=R 5 The intermediate compound 1 corresponding to the epoxy group.

[0205] When manufacturing the fluorinated ether compound of this embodiment, examples of halogen compounds having an epoxy group used in the first reaction described above include epichlorohydrin, epibromohydrin, 2-(2-bromoethyl)ethylene oxide, 2-(2-chloroethyl)ethylene oxide, 2-(3-bromopropyl)ethylene oxide, and 2-(3-chloropropyl)ethylene oxide. In formula (1), R represents... 3 In equation (2), 'a' and / or 'R' represent R. 5 When c in formula (3) is an integer from 2 to 3, halogen compounds having an epoxy group can be used, for example, 2-(2-bromoethyl) ethylene oxide, 2-(2-chloroethyl) ethylene oxide, 2-(3-bromopropyl) ethylene oxide, 2-(3-chloropropyl) ethylene oxide, etc.

[0206] Next, we prepare to use R in equation (1) 2 (=R 4 =R 6 The two ends of the corresponding perfluoropolyether chain are respectively configured with hydroxymethyl (-CH2OH) fluorinated compounds. Furthermore, the hydroxyl group of the hydroxymethyl group configured at one end of the above-mentioned fluorinated compound, and the R group having the same characteristics as in formula (1), are further configured to... 1 (=R 7 The epoxide compound reacts with the corresponding group (second reaction). Thus, a compound is obtained that reacts with R... 2 (=R 6 One end of the corresponding perfluoropolyether chain has a property similar to R.1 (=R 7 Intermediate compound 2 corresponding to the group.

[0207] With R 1 (=R 7 The epoxides corresponding to the hydroxyl groups can react with the above-mentioned fluorine compounds after the hydroxyl groups are protected with appropriate protecting groups.

[0208] In manufacturing the fluorinated ether compound of this embodiment, the epoxy compound used in the second reaction described above can be, for example, made to have an R that is similar to that of the manufactured fluorinated ether compound. 1 (or R) 7 The epoxide is synthesized by reacting an alcohol with the corresponding structure with any compound containing an epoxy group selected from epichlorohydrin, epibromohydrin, 2-bromoethyl ethylene oxide, and allyl glycidyl ether. Such epoxides can be synthesized by oxidizing unsaturated bonds or can be purchased commercially available.

[0209] Then, the hydroxyl group of the hydroxymethyl group at one end of the intermediate compound 2 reacts with the epoxy groups at both ends of the intermediate compound 1 (third reaction).

[0210] By performing the above steps, it is possible to manufacture R in formula (1). 2 R 4 R 6 The three PFPE chains shown have the same structure, R 1 With R 7 Same, R 3 With R 5 The same compound. Here, the order of the first and second reactions can be reversed.

[0211] Furthermore, for example, as a fluorinated ether compound represented by formula (1), in the manufacture of R 2 R 4 R 6 Same, R 3 With R 5 Same, and R 1 With R 7 Different compounds can be manufactured using the methods shown below.

[0212] That is, by synthesizing in the second reaction described above, the compounds having the same properties as R are respectively synthesized. 1 Intermediate compound 2a with corresponding group, and having R 7 Intermediate compound 2b corresponding to the group. Then, in the third reaction described above, intermediate compounds 2a and 2b are reacted with R at the ends of intermediate compound 1. 3 (=R5 It can be manufactured by reacting the corresponding epoxy groups sequentially.

[0213] Furthermore, for example, as a fluorinated ether compound represented by formula (1), in the manufacture of R 2 R 4 R 6 Same, R 1 With R 7 Same, and R 3 With R 5 Different compounds can be manufactured using the methods shown below.

[0214] That is, by making R have the same properties in the first reaction described above. 3 Halogen compounds with corresponding epoxy groups, and those with R 5 The corresponding halogenated compounds with epoxy groups react sequentially with the hydroxyl groups of the hydroxymethyl groups disposed at the ends of the aforementioned fluorinated compounds. Thus, a compound is obtained that reacts with R... 4 One end of the corresponding perfluoropolyether chain has a property similar to R. 3 The corresponding epoxy group has a corresponding R at the other end. 5 The corresponding epoxy group intermediate compound 1a. Then, in the third reaction described above, the intermediate compound 1a is used instead of intermediate compound 1 to manufacture it.

[0215] Furthermore, for example, as a fluorinated ether compound represented by formula (1), in the manufacture of R 1 With R 7 Same, R 3 With R 5 Same, and R 2 and R 6 The two PFPE chains shown, and R 4 In the case of compounds with different PFPE chains, the following manufacturing methods can be used to manufacture them.

[0216] That is, in the first and second reactions described above, fluorinated compounds with different types of PFPE chains are used; otherwise, they can be manufactured by the same method as described above.

[0217] Furthermore, for example, as a fluorinated ether compound represented by formula (1), in the manufacture of R 1 With R 7 Same or different, R 3 With R 5 Same, and R 2 R 4 R 6 When the PFPE chains shown are different compounds, they can be manufactured using the manufacturing methods shown below.

[0218] That is, in the second reaction described above, two substances with different types of PFPE chains than the fluorine compounds used in the first reaction are used as fluorine compounds. Furthermore, in the second reaction, substances with different types of PFPE chains than the fluorine compounds used in the first reaction are synthesized respectively. 2 One end of the corresponding perfluoropolyether chain has a property similar to R. 1 The intermediate compound 2c corresponding to the group, and in relation to R 6 One end of the corresponding perfluoropolyether chain has a property similar to R. 7 Intermediate compound 2d corresponding to the group. Then, in the third reaction described above, intermediate compound 2c and intermediate compound 2d are reacted with each of the R groups positioned at the ends of intermediate compound 1. 3 (=R 5 It can be manufactured by reacting the corresponding epoxy groups sequentially.

[0219] Here, the function of the lubricating layer formed on the protective layer using a lubricant containing a fluorinated ether compound of this embodiment will be explained.

[0220] One cause of corrosion in magnetic recording media is the presence of ionic contaminants on its surface. These ionic contaminants mostly adhere from the outside during the manufacturing process. Sometimes, they can also infiltrate the environment within the hard disk drive (magnetic recording playback device) and adhere to the magnetic recording media. Specifically, for example, because magnetic recording media and / or hard disk drives are kept under high temperature / high humidity conditions, water containing ions and other environmental substances can sometimes adhere to the surface of the magnetic recording media. If this water, containing ions and other environmental substances, penetrates the lubricating layer formed on the surface of the magnetic recording media, it causes the trace amounts of ions present beneath the lubricating layer to condense, resulting in the formation of ionic contaminants.

[0221] Since the fluorinated ether compound of this embodiment is a compound represented by formula (1), the lubricating layer containing it has a high corrosion inhibition effect that prevents contaminants from penetrating into the magnetic recording medium. This effect is achieved through the synergistic effect of the lubricating layer containing the fluorinated ether compound of this embodiment having the functions of <1> to <5> described below, and thus through excellent adhesion to the protective layer, appropriate hydrophobicity, and ease of formation on the protective layer in a uniform coating state.

[0222] <1> The above-mentioned lubricating layer is formed by R in the compound shown in formula (1). 3 and R 5 Each has one or more hydroxyl groups (-OH), and R 1 and R 7Each layer contains two or three polar groups, which interact appropriately with the protective layer, resulting in a tight seal. Therefore, the aforementioned lubricating layer can prevent contaminants from penetrating into the magnetic recording medium and can inhibit corrosion of the magnetic recording medium.

[0223] <2> For the fluorinated ether compound shown in formula (1), the three perfluorinated polyether chains (R 2 R 4 R 6 They are respectively configured in R 1 With R 3 Between, R 3 With R 5 Between, R 5 With R 7 between.

[0224] Therefore, R 1 The polar groups it possesses and R 3 The distance of the hydroxyl groups, R 3 With R 5 The distance between the hydroxyl groups, R 5 The hydroxyl group and R 7 The distances between the polar groups are all appropriate. Therefore, R 3 and R 5 The hydroxyl group and R 1 and R 7 The polar groups they possess do not readily hinder binding to active sites on the protective layer through adjacent polar groups. Therefore, R 3 and R 5 The hydroxyl group and R it contains 1 and R 7 The polar groups in these compounds readily participate in the binding of active sites on the protective layer. In other words, none of the polar groups in the aforementioned fluorinated ether compounds are likely to become polar groups that do not participate in the binding of active sites on the protective layer. As a result, for the lubricating layer containing the aforementioned fluorinated ether compounds, the number of polar groups that do not participate in the binding of active sites on the protective layer is suppressed, resulting in excellent adhesion to the protective layer.

[0225] In addition, R 3 The hydroxyl group and R 5 The distance of the hydroxyl groups, R 1 The polar groups it possesses and R 3 The distance of the hydroxyl groups, R 5 The hydroxyl group and R 7 The distances between the polar groups are all appropriate, therefore R 3 R 5 R 1 R 7The polar groups have small intramolecular interactions and are not easily aggregated. Therefore, the fluorinated ether compound shown in formula (1) is easy to wet and spread on the protective layer, has a uniform coating state, high coating rate, and can form a well-adhesive lubricating layer on the protective layer.

[0226] Furthermore, each perfluoropolyether chain (R 2 R 4 R 6 The two ends of ) are respectively connected to R 3 R 5 R 1 R 7 The polar groups of any of them adhere closely to the protective layer. Therefore, the fluorinated ether compound coated on the protective layer is not easily in a large volume state. Therefore, the fluorinated ether compound shown in formula (1) is easy to wet and spread on the protective layer, has a uniform coating state, a high coating rate, and can form a well-adhesive lubricating layer on the protective layer.

[0227] <3> The fluorinated ether compound shown in formula (1) has three perfluorinated polyether chains (R 2 R 4 R 6 The perfluoropolyether chains contained in the lubricating layer pass through the surface of the coated protective layer, and the low surface energy imparts water resistance to the lubricating layer.

[0228] If the fluorinated ether compound of formula (1) contained in the lubricating layer is maintained under high temperature / high humidity conditions, thermally induced molecular motion will occur. It can be assumed that water containing environmental substances such as ions will penetrate into the lubricating layer from the gaps between molecules undergoing molecular motion.

[0229] The lubricating layer containing the fluorinated ether compound shown in formula (1) has appropriate water resistance and hydrophobicity, thus preventing water from penetrating into the magnetic recording medium from the gaps between molecules in molecular motion, thereby improving the corrosion resistance of the magnetic recording medium.

[0230] <4> For the fluorinated ether compound shown in formula (1), R 3 R is the linking base shown in equation (2). 5 The linker shown in formula (3) is a group in formula (2) where a and c in formula (3) are not both 1. That is, the carbon atom of the fluorinated ether compound shown in formula (1) that is bonded to the hydroxyl group in formula (2) and / or formula (3) is related to R. 4 The compounds have methylene chains with 2 or 3 carbon atoms. Therefore, compared with the compounds in formula (2) where a is 1 and in formula (3) where c is 1, the fluorinated ether compound shown in formula (1) has R 3 and / or R 5The linker shown contains a large number of carbon atoms and has good hydrophobicity. Therefore, the lubricating layer containing the fluorinated ether compound shown in formula (1) is not easily penetrated by water and can prevent water from penetrating into the magnetic recording medium.

[0231] <5> For the fluorinated ether compound shown in formula (1), R 1 and R 7 Each of the contained polar groups bonds to a different carbon atom, and the carbon atoms bonded to the polar groups are linked to each other via linking groups containing carbon atoms of unbonded polar groups. Therefore, through R... 1 and R 7 The carbon atoms bonded to the polar groups contained therein, and R 1 and R 7 The hydrophobicity of the carbon atoms contained in the linker group results in a lubricating layer containing the fluorinated ether compound of formula (1) having suitable hydrophobicity. As a result, water does not easily penetrate the lubricating layer containing the fluorinated ether compound of formula (1), which can prevent water from penetrating into the magnetic recording medium and can inhibit the corrosion of the magnetic recording medium.

[0232] Lubricant for magnetic recording media

[0233] The lubricant for the magnetic recording medium in this embodiment comprises a fluorinated ether compound as shown in formula (1).

[0234] Regarding the lubricant of this embodiment, any 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.

[0235] Specific examples of known materials include, for instance, FOMBLIN (registered trademark) ZDIAC, FOMBLIN ZDEAL, FOMBLIN AM-2001 (and above, manufactured by Solvay Solexis), Moresco A20H (manufactured by Moresco), etc. The known materials used in combination with the lubricant of this embodiment preferably have a number average molecular weight of 1000 to 10000.

[0236] In the case where the lubricant of this embodiment contains materials other than the fluorinated ether compound shown in formula (1), it is preferable that the content of the fluorinated ether compound shown in formula (1) in the lubricant of this embodiment is 50% by mass or more, more preferably 70% by mass or more. The content of the fluorinated ether compound shown in formula (1) may be 80% by mass or more, or 90% by mass or more.

[0237] The lubricant of this embodiment contains a fluorinated ether compound as shown in formula (1), thus enabling the formation of a lubricating layer with high corrosion inhibition effect on the magnetic recording medium. Because the lubricating layer formed by the lubricant of this embodiment has a high corrosion inhibition effect on the magnetic recording medium, its thickness can be thin.

[0238] [Magnetic recording media]

[0239] 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.

[0240] For the magnetic recording medium of this embodiment, one or more base layers may be provided between the substrate and the magnetic layer as needed. Alternatively, an adhesion layer and / or a soft magnetic layer may be provided between the base layer and the substrate.

[0241] Figure 1 A schematic cross-sectional view showing one embodiment of the magnetic recording medium of the present invention.

[0242] 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.

[0243] "Substrate"

[0244] As substrate 11, for example, a non-magnetic substrate on which a film formed of NiP or NiP alloy is formed on a substrate formed of a metal or alloy material such as Al or Al alloy can be used.

[0245] Furthermore, as substrate 11, a non-magnetic substrate formed 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 formed of these non-metallic materials can be used.

[0246] "Adhesion layer"

[0247] The adhesion layer 12 prevents corrosion of the substrate 11 when the substrate 11 is disposed in contact with the soft magnetic layer 13 disposed on the adhesion layer 12.

[0248] The material of the adhesion layer 12 can be appropriately selected from, for example, Cr, Cr alloy, Ti, Ti alloy, CrTi, NiAl, AlRu alloy, etc. The adhesion layer 12 can be formed, for example, by sputtering.

[0249] "Soft magnetic layer"

[0250] 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 a structure in which the soft magnetic films above and below the intermediate layer are antiferroic coupled (AFC) by sandwiching an intermediate layer made of Ru film between the two soft magnetic films.

[0251] Examples of materials that can be used for the first and second soft magnetic films include CoZrTa alloys and CoFe alloys.

[0252] Preferably, any one of Zr, Ta, and Nb is added to the CoFe alloy used in the first and second soft magnetic films. 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.

[0253] The soft magnetic layer 13 can be formed, for example, by sputtering.

[0254] "First basal layer"

[0255] 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.

[0256] Examples of first base layers 14 include Cr layers, Ta layers, Ru layers, or CrMo alloy layers, CoW alloy layers, CrW alloy layers, CrV alloy layers, CrTi alloy layers, etc.

[0257] The first base layer 14 can be formed, for example, by sputtering.

[0258] "Second basal layer"

[0259] The second substrate layer 15 is a layer controlled in such a way that the orientation of the magnetic layer 16 becomes well. The second substrate layer 15 is preferably a layer formed of Ru or a Ru alloy.

[0260] 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.

[0261] The second base layer 15 can be formed, for example, by sputtering.

[0262] "Magnetic layer"

[0263] The magnetic layer 16 is composed of a magnetic film whose easy magnetization axis is oriented vertically or horizontally relative to the substrate surface. The magnetic layer 16 is a layer containing Co and Pt, and further, in order to improve the SNR characteristics, it can be a layer containing oxides, Cr, B, Cu, Ta, Zr, etc.

[0264] Examples of oxides contained in the magnetic layer 16 include SiO2, SiO, Cr2O3, CoO, Ta2O3, and TiO2.

[0265] The magnetic layer 16 can consist of a single layer or multiple magnetic layers composed of different materials.

[0266] For example, when the magnetic layer 16 is composed of three layers—a first magnetic layer, a second magnetic layer, and a third magnetic layer—stacked sequentially from bottom to top, the first magnetic layer is preferably a granular structure formed of a material containing Co, Cr, and Pt, and further containing oxides. As the oxide contained in the first magnetic layer, oxides of, for example, Cr, Si, Ta, Al, Ti, Mg, and Co are preferred. In particular, TiO2, Cr2O3, and SiO2 are suitable. Furthermore, the first magnetic layer is preferably formed of a composite oxide containing two or more oxides. In particular, Cr2O3-SiO2, Cr2O3-TiO2, and SiO2-TiO2 are suitable.

[0267] In addition to Co, Cr, Pt, and oxides, the first magnetic layer may contain one or more elements selected from B, Ta, Mo, Cu, Nd, W, Nb, Sm, Tb, Ru, and Re.

[0268] The second magnetic layer can be made of the same material as the first magnetic layer. The second magnetic layer is preferably granular.

[0269] The third magnetic layer is preferably a non-granular structure formed of a material containing Co, Cr, and Pt but not containing 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.

[0270] 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.

[0271] The non-magnetic layer disposed between adjacent magnetic layers of magnetic layer 16 can be, for example, Ru, Ru alloy, CoCr alloy, CoCrX1 alloy (X1 represents one or more elements selected from Pt, Ta, Zr, Re, Ru, Cu, Nb, Ni, Mn, Ge, Si, O, N, W, Mo, Ti, V, B, etc.).

[0272] Preferably, an alloy material comprising oxides, metal nitrides, or metal carbides is used in the non-magnetic layer disposed between adjacent magnetic layers of the magnetic layer 16. 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.

[0273] Non-magnetic layers can be formed, for example, by sputtering.

[0274] 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.

[0275] 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.

[0276] "Protective layer"

[0277] The protective layer 17 protects the magnetic layer 16. The protective layer 17 can be composed of one layer or multiple layers. Examples of materials for the protective layer 17 include carbon, nitrogen-containing carbon, and silicon carbide.

[0278] 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.

[0279] The adhesion between the carbon-based protective layer and the lubricating layer 18 can be controlled by making the carbon-based protective layer hydrogenated carbon and / or nitrided carbon, and adjusting the hydrogen and / or nitrogen content in the carbon-based protective layer. The hydrogen content in the carbon-based protective layer, when measured by hydrogen forward scattering (HFS), is preferably 3 to 20 atomic percent. Furthermore, the nitrogen content in the carbon-based protective layer, when measured by X-ray photoelectron spectrophotometry (XPS), is preferably 4 to 15 atomic percent.

[0280] 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 suitable for the carbon-based protective layer to have a tilted composition in which nitrogen is contained on the lubrication layer 18 side of the protective layer 17 and hydrogen is contained on the magnetic layer 16 side of the protective layer 17. In this case, the adhesion between the magnetic layer 16 and the lubrication layer 18 and the carbon-based protective layer is further improved.

[0281] The thickness of the protective layer 17 is preferably 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 is fully obtained. If the thickness of the protective layer 17 is 7 nm or less, it is preferred from the viewpoint of thinning the protective layer 17.

[0282] The film formation method for the protective layer 17 can be: sputtering using a target containing carbon, CVD (chemical vapor deposition) using hydrocarbon raw materials such as ethylene and toluene, IBD (ion beam deposition), etc.

[0283] When forming a carbon-based protective layer as protective layer 17, the film can be formed by, for example, 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.

[0284] "Lubrication layer"

[0285] 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.

[0286] Lubricating layer 18 Figure 1 As shown, it is formed on the protective layer 17 in contact with the ground. The lubricating layer 18 contains the aforementioned fluorinated ether compound.

[0287] When the protective layer 17 disposed under the lubricating layer 18 is a carbon-based protective layer, the lubricating layer 18 is bonded to the protective layer 17 with a high bonding force. As a result, it is easy to obtain a magnetic recording medium 10 in which the surface of the protective layer 17 is covered with a high coverage even if the thickness of the lubricating layer 18 is thin, and contamination of the surface of the magnetic recording medium 10 can be effectively prevented.

[0288] 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 be formed with 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. Furthermore, 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 sufficiently small.

[0289] If the surface of the protective layer 17 is not sufficiently covered by the lubricating layer 18, environmental substances adsorbed on the surface of the magnetic recording medium 10 can penetrate through the gaps in the lubricating layer 18 and intrude beneath it. These infiltrated environmental substances adsorb and combine with the protective layer 17, generating contaminants. These generated contaminants (agglomerated components) adhere (transfer) to the magnetic head as stains during magnetic recording and regeneration, causing head damage or reducing the magnetic recording and regeneration characteristics of the magnetic recording and regeneration device.

[0290] Examples of environmental substances that contribute to the formation of pollutants include, for example, 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 included as ionic impurities include, for example, sodium ions and potassium ions. Examples of inorganic ions included as ionic impurities include, for example, chloride ions, bromide ions, nitrate ions, sulfate ions, and ammonium ions. Examples of organic ions included as ionic impurities include, for example, oxalate ions and formate ions.

[0291] "Methods for forming a lubricating layer"

[0292] As a method for forming the lubricating layer 18, for example, a magnetic recording medium in the manufacturing process in which layers up to the protective layer 17 are formed on the substrate 11 is prepared, a lubricating layer forming solution is applied to the protective layer 17, and then dried.

[0293] The lubricating layer forming solution is obtained by dissolving the lubricant for the magnetic recording medium described in the above embodiment in a solvent as needed, and adjusting the viscosity and concentration to be suitable for the coating method.

[0294] Solvents used in solutions for forming lubricating layers include, for example, fluorinated solvents such as Bartel XF (trade name, manufactured by Mitsui Dupont Froroike Mikaru Co., Ltd.).

[0295] There are no particular limitations on the application method of the solution for forming the lubricating layer; examples include spin coating, spray coating, paper coating, and impregnation.

[0296] When using the immersion method, for example, the following method can be used. First, a substrate 11, with each layer up to the protective layer 17, is immersed in a lubricant layer forming solution added to the immersion tank of the immersion coating apparatus. Then, the substrate 11 is pulled out of the immersion tank at a predetermined speed. As a result, the lubricant layer forming solution is coated onto the surface of the protective layer 17 on the substrate 11.

[0297] 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.

[0298] In this embodiment, it is preferable to perform a polishing (precision grinding) process after forming a lubricating layer 18 on the surface of the substrate 11. By performing the polishing process, protrusions, defects, and particles present on the surface of the substrate 11 where the lubricating layer 18 is formed can be removed, resulting in a smooth magnetic recording medium 10. If the surface of the magnetic recording medium 10 is smooth, the distance loss between the magnetic recording medium 10 and the magnetic head can be reduced, thereby improving signal characteristics.

[0299] The polishing process can be, for example, a process of scanning a polishing belt on the surface of the substrate 11 on which the lubricating layer 18 has been formed. The polishing belt can be, for example, a substance composed of a resin film that retains the abrasive grains. The abrasive grain size can be, for example, #6000 to #20000.

[0300] 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.

[0301] The heat treatment temperature is preferably 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 is sufficiently achieved. Furthermore, by keeping the heat treatment temperature below 180°C, thermal decomposition of the lubricating layer 18 can be prevented. The heat treatment time is preferably 10–120 minutes.

[0302] 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 this embodiment, a lubricating layer 18 containing the aforementioned fluorinated ether compound is formed on the protective layer 17 in contact with the ground. This lubricating layer 18 has a high effect on inhibiting corrosion of the magnetic recording medium 10. Therefore, the magnetic recording medium 10 of this embodiment has fewer contaminants on its surface, exhibiting excellent corrosion resistance, reliability, and durability. Furthermore, because the magnetic recording medium 10 of this embodiment has a lubricating layer 18 with a high corrosion inhibition effect, the thickness of the protective layer 17 and / or the lubricating layer 18 can be thin. Moreover, the lubricating layer 18 in the magnetic recording medium 10 of this embodiment is less prone to the generation of foreign matter (stains), thus suppressing pickup.

[0303] Example

[0304] The present invention will be further described in detail below through examples and comparative examples. However, the present invention is not limited to the following examples.

[0305] [Example 1]

[0306] The compound shown in formula (A) above was produced by the method shown below.

[0307] (First reaction)

[0308] Under a nitrogen atmosphere, add HOCH2CF2O(CF2CF2O) to a 200mL round-bottom flask. r 9.4 g (20 mmol) of the compound CF2CH2OH (where r represents the average degree of polymerization, 2.5) (number-average molecular weight 468, molecular weight distribution 1.1), 1.76 g (44 mmol) of 60% sodium hydride, and 15.6 mL of N,N-dimethylformamide were stirred at room temperature until homogeneous. 6.34 g (42 mmol) of 2-(2-bromoethyl)ethylene oxide was added to this homogeneous liquid, and the mixture was stirred at 40 °C for 2 hours to allow the reaction to proceed.

[0309] After the reaction, the resulting product was cooled to 25°C, and 80 mL of water was added to stop the reaction. The product was then transferred to a separatory funnel and extracted twice with 150 mL of ethyl acetate. The organic layer was washed with saturated brine and dehydrated with anhydrous sodium sulfate. After filtration to separate the desiccant, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 3.7 g (molecular weight 608, 6.0 mmol) of the compound represented by formula (10) as intermediate compound 1.

[0310]

[0311] (In equation (10), r represents the average degree of polymerization, which is 2.5.)

[0312] (Second reaction)

[0313] Under a nitrogen atmosphere, add HOCH2CF2O(CF2CF2O) to a 200mL round-bottom flask. r 14.0 g of the compound represented by CF2CH2OH (where r represents the average degree of polymerization, which is 2.5) (number average molecular weight 468, molecular weight distribution 1.1), 3.89 g of the compound represented by formula (11) below (molecular weight 216.28, 18 mmol), and 28 mL of tert-butanol were stirred at room temperature until homogeneous. 1.0 g of potassium tert-butoxide (molecular weight 112.2, 9 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.

[0314] The compound shown in formula (11) is synthesized by protecting one hydroxyl group of 1,3-propanediol with a THP group (tetrahydropyranyl) and reacting the other hydroxyl group with epibromoethanol.

[0315] After the reaction, the resulting 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 with anhydrous sodium sulfate. After filtration to separate the desiccant, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 8.2 g (molecular weight 684, 12.0 mmol) of the compound shown in formula (12) as intermediate compound 2.

[0316]

[0317] (In formula (11), THP represents tetrahydropyranyl.)

[0318] (In equation (12), r represents the average degree of polymerization, which is 2.5.)

[0319] (Third reaction)

[0320] Under a nitrogen atmosphere, 6.8 g of intermediate compound 2 (representing the average degree of polymerization r as 2.5) of formula (12), 0.34 g of potassium tert-butoxide, and 9.4 mL of tert-butanol were added to a 200 mL flask and stirred at room temperature until homogeneous. Then, 1.8 g of intermediate compound 1 (representing the average degree of polymerization r as 2.5) of formula (10) was added to the homogeneous liquid, and the mixture was stirred at 70 °C for 16 hours to allow the reaction to proceed.

[0321] After the reaction, the resulting 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 filtration to separate the product from the desiccant, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 3.3 g (molecular weight 1809, 1.8 mmol) of the compound shown in formula (A) (where Fpa1 and Fpa2 are represented by formula (AF). The ra value representing the average degree of polymerization in Fpa1 is 2.5, and the ra value representing the average degree of polymerization in Fpa2 is 2.5).

[0322] The resulting compound (A) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0323] 1 H-NMR (CD3COCD3): δ[ppm]=1.38~1.75(8H), 3.37~4.31(46H)

[0324] 19F-NMR (CD3COCD3): δ[ppm]=-78.6(6F), -81.3(6F), -90.0~-88.5(30F)

[0325] [Example 2]

[0326] It replaces HOCH2CF2O(CF2CF2O) in the first reaction. r The compound represented by CF2CH2OH (where r represents the average degree of polymerization, which is 2.5) was used, instead of HOCH2CF2CF2O (CF2CF2CF2O). q 13.9 g of the compound shown in the formula CF2CF2CH2OH (where q represents the average degree of polymerization and is 2.5) (number-average molecular weight 693, molecular weight distribution 1.1) replaced HOCH2CF2O (CF2CF2O) in the second reaction. r The compound represented by CF2CH2OH (where r represents the average degree of polymerization, which is 2.5) was used, instead of HOCH2CF2CF2O (CF2CF2CF2O). q 20.8 g of the compound represented by CF2CF2CH2OH (where q represents the average degree of polymerization and is 2.5) (number average molecular weight 693, molecular weight distribution 1.1) and 6.02 g of the compound represented by formula (13) were used instead of the compound represented by formula (11). Otherwise, the same procedure as in Example 1 was performed to obtain 4.7 g of the compound represented by formula (B) (where Fdb1 and Fdb2 in formula (B) are represented by formula (BF). The qb representing the average degree of polymerization in Fdb1 is 2.5, and the qb representing the average degree of polymerization in Fdb2 is 2.5). (molecular weight 2632, 1.8 mmol)

[0327] The compound shown in formula (13) was synthesized by the following method.

[0328] A TBS group (tert-butyldimethylsilyl) was introduced into the primary hydroxyl group of 3-allyloxy-1,2-propanediol, and a MOM group (methoxymethyl) was introduced into the secondary hydroxyl group of the resulting compound. After removing the TBS group from the resulting compound, the resulting primary hydroxyl group was reacted with 2-(chloropropoxy)tetrahydro-2H-pyran. The double bond of the resulting compound was oxidized. Through the above steps, the compound shown in formula (13) was obtained.

[0329]

[0330] (In formula (13), THP represents tetrahydropyranyl and MOM represents methoxymethyl.)

[0331] The resulting compound (B) was subjected to... 1H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0332] 1 H-NMR (CD3COCD3): δ[ppm]=1.37~1.81(8H), 3.36~4.35(58H)

[0333] 19 F-NMR (acetone-D6): δ [ppm] = -84.0 to -83.0 (30F), -86.4 (12F), -124.3 (12F), -130.0 to -129.0 (15F)

[0334] [Example 3]

[0335] It replaces HOCH2CF2O(CF2CF2O) in the first reaction. r The compound represented by CF2CH2OH (where r represents the average degree of polymerization, which is 2.5) was used, instead of HOCH2CF2O (CF2CF2O). s (CF2O) t 12.7 g of the compound CF2CH2OH (where s and t represent the average degree of polymerization, and t is 2.5) (number-average molecular weight 633, molecular weight distribution 1.1) was used in the second reaction to replace HOCH2CF2O (CF2CF2O). r The compound represented by CF2CH2OH (where r represents the average degree of polymerization, which is 2.5) was used, instead of HOCH2CF2O (CF2CF2O). s (CF2O) t 19.0 g of the compound represented by CF2CH2OH (where s and t represent the average degree of polymerization, respectively, are 2.5) (number-average molecular weight 633, molecular weight distribution 1.1), and 3.10 g of the compound represented by the following formula (14) were used instead of the compound represented by formula (11). Otherwise, the same procedure as in Example 1 was performed to obtain 4.0 g of the compound represented by the above formula (C) (where Ffc1 and Ffc2 in formula (C) are represented by formula (CF). sc and tc, representing the average degree of polymerization, are 2.5 in Ffc1 and 2.5 in Ffc2). (molecular weight 2216, 1.8 mmol)

[0336] The compound shown in formula (14) was synthesized by introducing a THP group (tetrahydropyranyl) into the primary hydroxyl group of 3-buten-1-ol, thereby oxidizing the double bond of the resulting compound.

[0337]

[0338] (In formula (14), THP represents tetrahydropyranyl.)

[0339] The resulting compound (C) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0340] 1 H-NMR (CD3COCD3): δ[ppm]=1.34~1.67(8H), 3.39~4.34(38H)

[0341] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(15F), -77.7(6F), -80.3(6F), -91.0~-88.5(30F)

[0342] [Example 4]

[0343] In the second reaction, instead of the compound shown in formula (11), 4.76 g of the compound shown in formula (15) was used. Otherwise, the same procedure as in Example 1 was performed to obtain 3.4 g (molecular weight 1897, 1.8 mmol) of the compound shown in formula (D) (in formula (D), Fpd1 and Fpd2 are represented by formula (DF). The rd value representing the average degree of polymerization in Fpd1 is 2.5, and the rd value representing the average degree of polymerization in Fpd2 is 2.5).

[0344] The compound shown in formula (15) was synthesized by the following method.

[0345] Benzaldehyde dimethyl acetal was reacted with 1,2,4-butanetriol to synthesize a compound in which the hydroxyl groups bonded to the carbons at positions 2 and 4 of 1,2,4-butanetriol were protected. This compound was then reacted with 2-bromoethyl ethylene oxide to synthesize the compound shown in formula (15).

[0346]

[0347] (In formula (15), Ph represents phenyl.)

[0348] The resulting compound (D) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0349] 1 H-NMR (CD3COCD3): δ[ppm]=1.34~1.65(12H), 3.42~4.35(50H)

[0350] 19 F-NMR (CD3COCD3): δ[ppm]=-78.6(6F), -81.3(6F), -90.0~-88.5(30F)

[0351] [Example 5]

[0352] In the second reaction, instead of the compound shown in formula (13), 3.64 g of the compound shown in formula (16) was used. Otherwise, the same procedure as in Example 2 was performed to obtain 4.4 g (molecular weight 2456, 1.8 mmol) of the compound shown in formula (E) (in formula (E), Fde1 and Fde2 are represented by formula (EF). The qe representing the average degree of polymerization in Fde1 is 2.5, and the qe representing the average degree of polymerization in Fde2 is 2.5).

[0353] The compound shown in formula (16) is synthesized by oxidizing a compound protected by ethylene glycol monoallyl ether using dihydropyran.

[0354]

[0355] (In formula (16), THP represents tetrahydropyranyl.)

[0356] The resulting compound (E) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0357] 1 H-NMR (CD3COCD3): δ[ppm]=1.37~1.64(4H), 3.42~4.35(46H)

[0358] 19 F-NMR (acetone-D6): δ [ppm] = -84.0 to -83.0 (30F), -86.4 (12F), -124.3 (12F), -130.0 to -129.0 (15F)

[0359] [Example 6]

[0360] In the second reaction, instead of the compound shown in formula (13), 3.89 g of the compound shown in formula (17) was used. Otherwise, the same procedure as in Example 2 was performed to obtain 4.5 g (molecular weight 2484, 1.8 mmol) of the compound shown in formula (F) (in formula (F), Fdf1 and Fdf2 are represented by formula (FF). The qf in Fdf1, which represents the average degree of polymerization, is 2.5, and the qf in Fdf2, which represents the average degree of polymerization, is 2.5).

[0361] The compound shown in formula (17) was synthesized by oxidizing the double bond of a compound obtained by reacting 3-buten-1-ol with 2-bromoethoxytetrahydropyran.

[0362]

[0363] (In formula (17), THP represents tetrahydropyranyl.)

[0364] The resulting compound (F) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0365] 1 H-NMR (CD3COCD3): δ[ppm]=1.34~1.59(8H), 3.37~4.38(46H)

[0366] 19 F-NMR (acetone-D6): δ [ppm] = -84.0 to -83.0 (30F), -86.4 (12F), -124.3 (12F), -130.0 to -129.0 (15F)

[0367] [Example 7]

[0368] In the second reaction, instead of the compound shown in formula (14), 4.51 g of the compound shown in formula (18) was used. Otherwise, the same procedure as in Example 3 was performed to obtain 4.3 g (molecular weight 2364, 1.8 mmol) of the compound shown in formula (G) (in formula (G), Ffg1 and Ffg2 are represented by formula (GF). The average degree of polymerization sg and tg in Ffg1 are 2.5, and the average degree of polymerization sg and tg in Ffg2 are 2.5.).

[0369] The compound shown in formula (18) was synthesized by the following method.

[0370] Benzaldehyde dimethyl acetal was reacted with 1,2,4-butanetriol to synthesize a compound in which the hydroxyl groups bonded to the carbons at positions 2 and 4 of 1,2,4-butanetriol were protected. This compound was then reacted with epibromoethanol to synthesize the compound shown in (18).

[0371]

[0372] (In formula (18), Ph represents phenyl.)

[0373] The resulting compound (G) was subjected to 1 H-NMR and 19The structure was identified by F-NMR measurements, and the following results were obtained.

[0374] 1 H-NMR (CD3COCD3): δ[ppm]=1.34~1.67(8H), 3.38~4.33(50H)

[0375] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(15F), -77.7(6F), -80.3(6F), -91.0~-88.5(30F)

[0376] [Example 8]

[0377] In the first reaction, 2-(3-bromopropyl)ethylene oxide was used instead of 2-(2-bromoethyl)ethylene oxide, and in the second reaction, 3.35 g of the compound shown in formula (19) was used instead of the compound shown in formula (11). Otherwise, the same procedure as in Example 1 was performed to obtain 3.2 g (molecular weight 1777, 1.8 mmol) of the compound shown in formula (H) (Fph1 and Fph2 in formula (H) are represented by formula (HF). The rh in Fph1, which represents the average degree of polymerization, is 2.5, and the rh in Fph2, which represents the average degree of polymerization, is 2.5).

[0378] The compound shown in formula (19) was synthesized by introducing a THP group (tetrahydropyranyl) into the primary hydroxyl group of 4-penten-1-ol, thereby oxidizing the double bond of the resulting compound.

[0379]

[0380] (In formula (19), THP represents tetrahydropyranyl.)

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

[0382] 1 H-NMR (CD3COCD3): δ[ppm]=1.34~1.65(16H), 3.42~4.35(38H)

[0383] 19 F-NMR (CD3COCD3): δ[ppm]=-78.6(6F), -81.3(6F), -90.0~-88.5(30F)

[0384] [Example 9]

[0385] In the first reaction, 2-(3-bromopropyl)ethylene oxide was used instead of 2-(2-bromoethyl)ethylene oxide, and in the second reaction, 6.99 g of the compound shown in formula (20) was used instead of the compound shown in formula (13). Otherwise, the same procedure as in Example 2 was performed to obtain 4.8 g (molecular weight 2688, 1.8 mmol) of the compound shown in formula (I) (Fdi1 and Fdi2 in formula (I) are represented by formula (IF). The qi in Fdi1, which represents the average degree of polymerization, is 2.5, and the qi in Fdi2, which represents the average degree of polymerization, is 2.5).

[0386] The compound shown in formula (20) was synthesized by the following method.

[0387] The compound in which ethylene glycol monoallyl ether was protected with dihydropyran was oxidized to obtain compound 1. Compound 1 was reacted with the hydroxyl group of 4-penten-1-ol to obtain compound 2. The double bond of the compound in which the secondary hydroxyl group of compound 2 was protected with a THP group was oxidized. Through the above steps, the compound shown in formula (20) was obtained.

[0388]

[0389] (In formula (20), THP represents tetrahydropyranyl.)

[0390] The resulting compound (I) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0391] 1 H-NMR (CD3COCD3): δ[ppm]=1.38~1.58(16H), 3.38~4.41(58H)

[0392] 19 F-NMR (acetone-D6): δ [ppm] = -84.0 to -83.0 (30F), -86.4 (12F), -124.3 (12F), -130.0 to -129.0 (15F)

[0393] [Example 10]

[0394] In the first reaction, 2-(3-bromopropyl)ethylene oxide was used instead of 2-(2-bromoethyl)ethylene oxide, and in the second reaction, 5.77 g of the compound shown in formula (21) was used instead of the compound shown in formula (14). Otherwise, the same procedure as in Example 3 was performed to obtain 4.4 g (molecular weight 2452, 1.8 mmol) of the compound shown in formula (J) (Ffj1 and Ffj2 in formula (J) are represented by formula (JF). The average degree of polymerization sj and tj in Ffj1 is 2.5, and the average degree of polymerization sj and tj in Ffj2 is 2.5.)

[0395] The compound shown in formula (21) was synthesized by the following method.

[0396] A tert-butyldimethylsilyl (TBS) group was introduced as a protecting group to the primary hydroxyl group of 3-allyloxy-1,2-propanediol, and a methoxymethyl (MOM) group was introduced as a protecting group to the secondary hydroxyl group of the resulting compound. Then, the TBS group was removed from the compound, and the resulting primary hydroxyl group was reacted with 2-bromoethoxytetrahydropyran. The double bond of the resulting compound was oxidized. Through the above steps, the compound shown in formula (21) was obtained.

[0397]

[0398] (In formula (21), THP represents tetrahydropyranyl and MOM represents methoxymethyl.)

[0399] The resulting compound (J) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0400] 1 H-NMR (CD3COCD3): δ[ppm]=1.34~1.66(8H), 3.39~4.35(58H)

[0401] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(15F), -77.7(6F), -80.3(6F), -91.0~-88.5(30F)

[0402] [Example 11]

[0403] It replaces HOCH2CF2O(CF2CF2O) in the second reaction. r The compound represented by CF2CH2OH (where r represents the average degree of polymerization, which is 2.5) was used, instead of HOCH2CF2CF2O (CF2CF2CF2O).q 20.8 g of the compound represented by CF2CF2CH2OH (where q, representing the average degree of polymerization, is 2.5) (number average molecular weight 693, molecular weight distribution 1.1), and 4.51 g of the compound represented by the above formula (18) instead of the compound represented by formula (11), were obtained by performing the same operation as in Example 1, yielding 4.2 g of the compound represented by the above formula (K) (where Fdk1 and Fpk1 in formula (K) are represented by formula (KF). qk, representing the average degree of polymerization, is 2.5 in Fdk1, and rk, representing the average degree of polymerization, is 2.5 in Fpk1) (molecular weight 2319, 1.8 mmol).

[0404] The resulting compound (K) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0405] 1 H-NMR (CD3COCD3): δ[ppm]=1.34~1.63(8H), 3.39~4.35(50H)

[0406] 19 F-NMR (CD3COCD3): δ[ppm]=-78.6(2F), -81.3(2F), -84.0~-83.0(20F), -86.4(8F), -90.0~-88.5(10F), -124.3(8F), -130.0~-129.0(10F)

[0407] [Example 12]

[0408] It replaces HOCH2CF2O(CF2CF2O) in the second reaction. r The compound represented by CF2CH2OH (where r represents the average degree of polymerization, which is 2.5) was used, instead of HOCH2CF2O (CF2CF2O). s (CF2O) t The compound represented by CF2CH2OH (where s and t represent the average degree of polymerization, respectively, are 2.5) (number-average molecular weight 633, molecular weight distribution 1.1), and the compound represented by the following formula (22) were used instead of the compound represented by formula (11). Otherwise, the same procedure as in Example 1 was performed to obtain 4.1 g (molecular weight 2287, 1.8 mmol) of the compound represented by the above formula (L) (where Ffl1 and Fpl1 in formula (L) are represented by formula (LF). sl and tl, representing the average degree of polymerization, are 2.5 in Ffl1, and rl, representing the average degree of polymerization, is 2.5 in Fpl1).

[0409] The compound shown in formula (22) was synthesized by the following method.

[0410] Using dihydropyran, ethylene glycol monoallyl ether was protected, and the resulting compound was oxidized to prepare compound 1. Next, compound 1 was reacted with the hydroxyl group of 3-buten-1-ol to prepare compound 2. The secondary hydroxyl group of the resulting compound 2 was protected with a MOM group, and the double bond was oxidized to obtain the compound shown in formula (22).

[0411]

[0412] (In formula (22), THP represents tetrahydropyranyl and MOM represents methoxymethyl.)

[0413] The resulting compound (L) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0414] 1 H-NMR (CD3COCD3): δ[ppm]=1.35~1.62(8H), 3.41~4.35(58H)

[0415] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(10F), -77.7(4F), -78.6(2F), -80.3(4F), -81.3(2F), -90.0~-88.5(30F)

[0416] [Example 13]

[0417] It replaces HOCH2CF2O(CF2CF2O) in the second reaction. r The compound represented by CF2CH2OH (where r represents the average degree of polymerization, which is 2.5) was used, instead of HOCH2CF2CF2O (CF2CF2CF2O). q 20.8 g of the compound represented by CF2CF2CH2OH (where q represents the average degree of polymerization and is 2.5) (number average molecular weight 693, molecular weight distribution 1.1) and 3.89 g of the compound represented by formula (11) were used instead of the compound represented by formula (19). Otherwise, the same operation as in Example 8 was performed to obtain 4.1 g of the compound represented by formula (M) (where Fdm1 and Fpm1 in formula (M) are represented by formula (MF). qm in Fdm1 represents the average degree of polymerization and rm in Fpm1 represents the average degree of polymerization and is 2.5). (molecular weight 2287, 1.8 mmol)

[0418] The resulting compound (M) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0419] 1 H-NMR (CD3COCD3): δ[ppm]=1.35~1.56(12H), 3.41~4.37(46H)

[0420] 19 F-NMR (CD3COCD3): δ[ppm]=-78.6(2F), -81.3(2F), -84.0~-83.0(20F), -86.4(8F), -90.0~-88.5(10F), -124.3(8F), -130.0~-129.0(10F)

[0421] [Example 14]

[0422] It replaces HOCH2CF2CF2O(CF2CF2CF2O) in the second reaction. q The compound represented by CF2CF2CH2OH (where q represents the average degree of polymerization, which is 2.5) was used, instead of HOCH2CF2O (CF2CF2O). r 14.0 g of the compound represented by CF2CH2OH (where r represents the average degree of polymerization and is 2.5) (number-average molecular weight 468, molecular weight distribution 1.1) was obtained. Otherwise, the same procedure as in Example 2 was performed to obtain 3.9 g of the compound represented by the above formula (N) (where Fdn1 and Fpn1 are represented by formula (NF). qn, representing the average degree of polymerization in Fdn1, is 2.5, and rn, representing the average degree of polymerization in Fpn1, is 2.5). (molecular weight 2182, 1.8 mmol)

[0423] The resulting compound (N) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0424] 1 H-NMR (CD3COCD3): δ[ppm]=1.39~1.61(8H), 3.41~4.45(58H)

[0425] 19 F-NMR (acetone-D6): δ [ppm] = -78.6 (4F), -81.3 (4F), -84.0~-83.0 (10F), -86.4 (4F), -90.0~-88.5 (24F), -124.3 (4F), -130.0~-129.0 (5F)

[0426] [Example 15]

[0427] In the second reaction, instead of the compound shown in formula (13) above, 4.76 g of the compound shown in formula (15) above was used. Otherwise, the same operation as in Example 14 was performed to obtain 3.8 g of the compound shown in formula (O) above (Fdo1 and Fpo1 in formula (O) are represented by formula (OF). The qo in Fdo1, which represents the average degree of polymerization, is 2.5, and the ro in Fpo1, which represents the average degree of polymerization, is 2.5.) (molecular weight 2122, 1.8 mmol).

[0428] The resulting compound (O) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0429] 1 H-NMR (CD3COCD3): δ[ppm]=1.34~1.58(12H), 3.38~4.41(50H)

[0430] 19 F-NMR (acetone-D6): δ [ppm] = -78.6 (4F), -81.3 (4F), -84.0~-83.0 (10F), -86.4 (4F), -90.0~-88.5 (24F), -124.3 (4F), -130.0~-129.0 (5F)

[0431] [Example 16]

[0432] It replaces HOCH2CF2CF2O(CF2CF2CF2O) in the second reaction. q The compound represented by CF2CF2CH2OH (where q represents the average degree of polymerization, which is 2.5) was used, instead of HOCH2CF2O (CF2CF2O). s (CF2O) t The compound represented by CF2CH2OH (where s and t, representing the average degree of polymerization, are 2.5) (number-average molecular weight 633, molecular weight distribution 1.1), and 4.15 g of the compound represented by formula (23) were used instead of the compound represented by formula (13) above. Otherwise, the same operation as in Example 2 was performed to obtain 4.3 g (molecular weight 2392, 1.8 mmol) of the compound represented by formula (P) above (where Fdp1 and Ffp1 in formula (P) are represented by formula (PF). qp, representing the average degree of polymerization in Fdp1, is 2.5. sp and tp, representing the average degree of polymerization in Ffp1, are 2.5).

[0433] The compound shown in formula (23) is synthesized by protecting one hydroxyl group of 1,4-butanediol with a THP group and reacting the other hydroxyl group with epibromoethanol.

[0434]

[0435] (In formula (23), THP represents tetrahydropyranyl.)

[0436] The resulting compound (P) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0437] 1 H-NMR (CD3COCD3): δ[ppm]=1.37~1.61(12H), 3.40~4.43(46H)

[0438] 19 F-NMR (acetone-D6): δ [ppm] = -55.6 to -50.6 (10F), -77.7 (4F), -80.3 (4F), -84.0 to -83.0 (10F), -86.4 (4F), -91.0 to -88.5 (20F), -124.3 (4F), -130.0 to -129.0 (5F)

[0439] [Example 17]

[0440] It replaces HOCH2CF2CF2O(CF2CF2CF2O) in the second reaction. q The compound represented by CF2CF2CH2OH (where q represents the average degree of polymerization, which is 2.5) was used, instead of HOCH2CF2O (CF2CF2O). s (CF2O) t The compound represented by CF2CH2OH (where s and t, representing the average degree of polymerization, are 2.5) (number-average molecular weight 633, molecular weight distribution 1.1), and 3.64 g of the compound represented by formula (16) were used instead of the compound represented by formula (20). Otherwise, the same operation as in Example 9 was performed to obtain 4.3 g of the compound represented by formula (Q) (where Fdq1 and Ffq1 in formula (Q) are represented by formula (QF). qq, representing the average degree of polymerization, is 2.5 in Fdq1, and sq and tq, representing the average degree of polymerization, are 2.5 in Ffq1). (molecular weight 2364, 1.8 mmol)

[0441] The resulting compound (Q) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0442] 1 H-NMR (CD3COCD3): δ[ppm]=1.36~1.57(8H), 3.39~4.37(46H)

[0443] 19 F-NMR (acetone-D6): δ [ppm] = -55.6 to -50.6 (10F), -77.7 (4F), -80.3 (4F), -84.0 to -83.0 (10F), -86.4 (4F), -91.0 to -88.5 (20F), -124.3 (4F), -130.0 to -129.0 (5F)

[0444] [Example 18]

[0445] It replaces HOCH2CF2O(CF2CF2O) in the second reaction. s (CF2O) t The compound represented by CF2CH2OH (where s and t represent the average degree of polymerization and are 2.5) was used, instead of HOCH2CF2O (CF2CF2O). r 14.0 g of the compound represented by CF2CH2OH (where r represents the average degree of polymerization and is 2.5) (number average molecular weight 468, molecular weight distribution 1.1) and 5.77 g of the compound represented by formula (21) were used instead of the compound represented by formula (14). Otherwise, the same procedure as in Example 3 was performed to obtain 3.8 g of the compound represented by formula (R) (where Ffr1 and Fpr1 in formula (R) are represented by formula (RF). sr and tr in Ffr1, representing the average degree of polymerization, are 2.5, and rr in Fpr1, representing the average degree of polymerization, is 2.5). (molecular weight 2094, 1.8 mmol)

[0446] The resulting compound (R) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0447] 1 H-NMR (CD3COCD3): δ[ppm]=1.34~1.59(4H), 3.40~4.43(58H)

[0448] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(5F), -77.7(2F), -78.6(4F), -80.3(2F), -81.3(4F), -90.0~-88.5(30F)

[0449] [Example 19]

[0450] It replaces HOCH2CF2O(CF2CF2O) in the second reaction. s (CF2O) t The compound represented by CF2CH2OH (where s and t represent the average degree of polymerization and are 2.5) was used, instead of HOCH2CF2CF2O (CF2CF2CF2O). q 20.8 g of the compound represented by CF2CF2CH2OH (where q, representing the average degree of polymerization, is 2.5) (number-average molecular weight 693, molecular weight distribution 1.1), and 3.61 g of the compound represented by formula (24) were used instead of the compound represented by formula (14) above. Otherwise, the same operation as in Example 3 was performed to obtain 4.3 g of the compound represented by formula (S) above (where Fds1 and Ffs1 are represented by formula (SF). qs, representing the average degree of polymerization, is 2.5 in Fds1, and ss and ts, representing the average degree of polymerization, are 2.5 in Ffs1). (molecular weight 2392, 1.8 mmol)

[0451] The compound shown in formula (24) was synthesized by introducing a THP group (tetrahydropyranyl) into the primary hydroxyl group of 5-hexen-1-ol, thereby oxidizing the double bond of the resulting compound.

[0452]

[0453] (In formula (24), THP represents tetrahydropyranyl.)

[0454] The resulting compound (S) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0455] 1 H-NMR (CD3COCD3): δ[ppm]=1.34~1.57(16H), 3.41~4.37(38H)

[0456] 19 F-NMR (CD3COCD3): δ [ppm] = -55.6~-50.6(5F), -77.7(2F), -80.3(2F), -84.0~- 83.0(20F), -86.4(8F), -91.0~-88.5(10F), -124.3(8F), -130.0~-129.0(10F)

[0457] [Example 20]

[0458] It replaces HOCH2CF2O(CF2CF2O) in the second reaction. s (CF2O) t The compound represented by CF2CH2OH (where s and t represent the average degree of polymerization and are 2.5) was used, instead of HOCH2CF2O (CF2CF2O). r The compound represented by CF2CH2OH (where r, representing the average degree of polymerization, is 2.5) (number-average molecular weight 468, molecular weight distribution 1.1), and 5.48 g of the compound represented by formula (25) were used instead of the compound represented by formula (21) above. Otherwise, the same operation as in Example 10 was performed to obtain 3.76 g (molecular weight 2090, 1.8 mmol) of the compound represented by formula (T) above (where Fft1 and Fpt1 are represented by formula (TF). st and tt, representing the average degree of polymerization, are 2.5 in Fft1, and rt, representing the average degree of polymerization, is 2.5 in Fpt1).

[0459] The compound shown in formula (25) was synthesized by the following method.

[0460] The secondary hydroxyl group of the compound obtained by reacting the compound shown in formula (19) with allyl alcohol was protected with a MOM group. The compound shown in formula (25) was obtained by oxidizing the double bond of the resulting compound.

[0461]

[0462] (In formula (25), THP represents tetrahydropyranyl and MOM represents methoxymethyl.)

[0463] The resulting compound (T) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0464] 1 H-NMR (CD3COCD3): δ[ppm]=1.35~1.60(16H), 3.42~4.42(50H)

[0465] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(5F), -77.7(2F), -78.6(4F), -80.3(2F), -81.3(4F), -90.0~-88.5(30F)

[0466] [Comparative Example 1]

[0467] The compound represented by the following formula (AA) was synthesized by the method described in Patent Document 1.

[0468]

[0469] (In formula (AA), Fpaa1 and Ffaa1 are represented by formula (AAF). In Fpaa1, paa, representing the average degree of polymerization, is 2.5, and in Ffaa1, maa and naa, representing the average degree of polymerization, are both 2.5.)

[0470] The resulting compound (AA) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0471] 1 H-NMR (CD3COCD3): δ[ppm]=3.42~4.28(38H)

[0472] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(10F), -77.7(4F), -78.6(2F), -80.3(4F), -81.3(2F), -90.0~-88.5(30F)

[0473] [Comparative Example 2]

[0474] The compound shown in formula (AB) was synthesized by the method described in Patent Document 1.

[0475]

[0476] (In formula (AB), Fpab1 and Ffab1 are represented by formula (ABF). In Fpab1, pab, which represents the average degree of polymerization, is 2.5, and in Ffab1, mab and nab, which also represent the average degree of polymerization, are both 2.5.)

[0477] The resulting compound (AB) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0478] (Authentication data)

[0479] 1 H-NMR (CD3COCD3): δ[ppm]=1.54~1.76(4H), 3.42~4.28(38H)

[0480] 19F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(10F), -77.7(4F), -78.6(2F), -80.3(4F), -81.3(2F), -90.0~-88.5(30F)

[0481] [Comparative Example 3]

[0482] The compound represented by the following formula (AC) was synthesized by the method described in Patent Document 1.

[0483]

[0484] (In equation (AC), Fpac1 and Ffac1 are represented by equation (ACF). In Fpac1, pac, which represents the average degree of polymerization, is 2.5, and in Ffac1, mac and nac, which also represent the average degree of polymerization, are both 2.5.)

[0485] The resulting compound (AC) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0486] (Authentication data)

[0487] 1 H-NMR (CD3COCD3): δ[ppm]=3.46~4.18(46H)

[0488] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(10F), -77.7(4F), -78.6(2F), -80.3(4F), -81.3(2F), -90.0~-88.5(30F)

[0489] [Comparative Example 4]

[0490] The compound shown in formula (AD) was synthesized by the method described in Patent Document 1.

[0491]

[0492] (In equation (AD), Fpad1 and Ffad1 are represented by equation (ADF). In Fpad1, pad, which represents the average degree of polymerization, is 2.5, and in Ffad1, mad and nad, which also represent the average degree of polymerization, are both 2.5.)

[0493] The resulting compound (AD) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0494] (Authentication data)

[0495] 1 H-NMR (CD3COCD3): δ[ppm]=1.34~1.67(4H), 3.39~4.34(46H)

[0496] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(10F), -77.7(4F), -78.6(2F), -80.3(4F), -81.3(2F), -90.0~-88.5(30F)

[0497] [Comparative Example 5]

[0498] The compound represented by the following formula (AE) was synthesized by the method described in Patent Document 2.

[0499]

[0500] (In formula (AE), Fpae1 and Ffae1 are represented by formula (AEF). In Fpae1, pae, which represents the average degree of polymerization, is 2.5, and in Ffae1, mae and nae, which also represent the average degree of polymerization, are both 2.5.)

[0501] The resulting compound (AE) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0502] (Authentication data)

[0503] 1 H-NMR (CD3COCD3): δ[ppm]=1.34~1.65(8H), 3.42~4.35(46H)

[0504] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(10F), -77.7(4F), -78.6(2F), -80.3(4F), -81.3(2F), -90.0~-88.5(30F)

[0505] [Comparative Example 6]

[0506] The compound shown in formula (AF) was synthesized by the following method.

[0507] In the first reaction, epibromoethanol was used instead of 2-(2-bromoethyl)ethylene oxide, and in the second reaction, 4.47 g of the compound shown in formula (26) was used instead of the compound shown in formula (22). Otherwise, the same procedure as in Example 12 was performed to obtain 3.9 g of the compound shown in formula (AF) (molecular weight 2143, 1.8 mmol).

[0508] The compound shown in formula (26) is obtained by oxidizing the double bond of the resulting compound by introducing THP groups as protecting groups into the primary and secondary hydroxyl groups of 3-allyloxy-1,2-propanediol.

[0509]

[0510] (In formula (26), THP represents tetrahydropyranyl.)

[0511] (In formula (AF), Fpaf1 and Ffaf1 are represented by formula (AFF). In Fpaf1, paf, which represents the average degree of polymerization, is 2.5, and in Ffaf1, maf and naf, which also represent the average degree of polymerization, are both 2.5.)

[0512] The resulting compound (AF) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0513] 1 H-NMR (CD3COCD3): δ [ppm] = 3.42~4.35 (50H)

[0514] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(10F), -77.7(4F), -78.6(2F), -80.3(4F), -81.3(2F), -90.0~-88.5(30F)

[0515] [Comparative Example 7]

[0516] The compound represented by the following formula (AG) was synthesized by the method described in Patent Document 2.

[0517]

[0518] (In formula (AG), Fpag1 and Ffag1 are represented by formula (AGF). In Fpag1, pag, which represents the average degree of polymerization, is 2.5, and in Ffag1, mag and nag, which also represent the average degree of polymerization, are both 2.5.)

[0519] The resulting compound (AG) was subjected to1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0520] (Authentication data)

[0521] 1 H-NMR (CD3COCD3): δ[ppm]=1.54~1.76(2H), 3.42~4.28(32H)

[0522] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(10F), -77.7(4F), -78.6(2F), -80.3(4F), -81.3(2F), -90.0~-88.5(30F)

[0523] [Comparative Example 8]

[0524] The compound represented by the following formula (AH) was synthesized by the method described in Patent Document 1.

[0525]

[0526] (In formula (AH), Fpah1 and Ffah1 are represented by formula (AHF). In Fpah1, ​​pah, which represents the average degree of polymerization, is 2.5, and in Ffah1, mah and nah, which also represent the average degree of polymerization, are both 2.5.)

[0527] The resulting compound (AH) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0528] (Authentication data)

[0529] 1 H-NMR (CD3COCD3): δ[ppm]=3.42~4.28(38H)

[0530] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(5F), -77.7(2F), -78.6(4F), -80.3(2F), -81.3(4F), -90.0~-88.5(30F)

[0531] [Comparative Example 9]

[0532] The compound shown in the following formula (AI) was synthesized by the method described in Patent Document 1.

[0533]

[0534] (In formula (AI), Fpai1 and Fpai2 are represented by formula (AIF). In Fpai1, pai, representing the average degree of polymerization, is 2.5, and in Fpai2, pai, representing the average degree of polymerization, is 2.5.)

[0535] The resulting compound (AI) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0536] (Authentication data)

[0537] 1 H-NMR (CD3COCD3): δ[ppm]=3.42~4.28(38H)

[0538] 19 F-NMR (CD3COCD3): δ[ppm]=-78.6(6F), -81.3(6F), -90.0~-88.5(30F)

[0539] [Comparative Example 10]

[0540] The compound represented by the following formula (AJ) was synthesized by the method described in Patent Document 1.

[0541]

[0542] (In equation (AJ), Ffaj1 and Ffaj2 are represented by equation (AJF). In Ffaj1, maj and naj, representing the average degree of polymerization, are 2.5, and in Ffaj2, maj and naj, representing the average degree of polymerization, are 2.5.)

[0543] The resulting compound (AJ) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0544] (Authentication data)

[0545] 1 H-NMR (CD3COCD3): δ[ppm]=3.42~4.28(38H)

[0546] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(15F), -77.7(6F), -80.3(6F), -91.0~-88.5(30F)

[0547] [Comparative Example 11]

[0548] The compound represented by the following formula (AK) was synthesized by the method described in Patent Document 2.

[0549]

[0550] (In formula (AK), Fpak1 and Fpak2 are represented by formula (AKF). In Fpak1, pak, representing the average degree of polymerization, is 2.5, and in Fpak2, pak, representing the average degree of polymerization, is 2.5.)

[0551] The resulting compound (AK) was subjected to 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0552] (Authentication data)

[0553] 1 H-NMR (CD3COCD3): δ [ppm] = 1 H-NMR (CD3COCD3): δ[ppm]=3.46~4.18(46H)

[0554] 19 F-NMR (CD3COCD3): δ[ppm]=-78.6(6F), -81.3(6F), -90.0~-88.5(30F)

[0555] [Comparative Example 12]

[0556] The compound represented by the following formula (AL) was synthesized by the method described in Patent Document 2.

[0557]

[0558] (In formula (AL), Ffal1 and Ffal2 are represented by formula (ALF). In Ffal1, mal and nal, which represent the average degree of polymerization, are 2.5, and in Ffal2, mal and nal, which represent the average degree of polymerization, are 2.5.)

[0559] The resulting compound (AL) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0560] (Authentication data)

[0561] 1 H-NMR (CD3COCD3): δ [ppm] = 1H-NMR (CD3COCD3): δ[ppm]=3.46~4.18(46H)

[0562] 19 F-NMR (CD3COCD3): δ[ppm]=-55.6~-50.6(15F), -77.7(6F), -80.3(6F), -91.0~-88.5(30F)

[0563] [Comparative Example 13]

[0564] The compound represented by the following formula (AM) was synthesized by the method described in Patent Document 2.

[0565]

[0566] (In formula (AM), Fpam1 and Fpam2 are represented by formula (AMF). In Fpam1, the pam representing the average degree of polymerization is 2.5, and in Fpam2, the pam representing the average degree of polymerization is 2.5.)

[0567] The resulting compound (AM) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0568] (Authentication data)

[0569] 1 H-NMR (CD3COCD3): δ[ppm]=3.46~4.18(32H)

[0570] 19 F-NMR (CD3COCD3): δ[ppm]=-78.6(6F), -81.3(6F), -90.0~-88.5(30F)

[0571] [Comparative Example 14]

[0572] The compound represented by the following formula (AN) was synthesized by the following method.

[0573] Under a nitrogen atmosphere, add HOCH2CF2O(CF2CF2O) to a 200mL round-bottom flask. r14.0 g of the compound CF2CH2OH (where r represents the average degree of polymerization, 2.5) (number-average molecular weight 468, molecular weight distribution 1.1), 2.34 g of tert-butyl glycidyl ether (molecular weight 130.19, 18 mmol), and 28 mL of tert-butanol were stirred at room temperature until homogeneous. 1.0 g of potassium tert-butoxide (molecular weight 112.2, 9 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.

[0574] After the reaction, the resulting 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 with anhydrous sodium sulfate. After filtration to separate the desiccant, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 7.2 g (molecular weight 598, 12.0 mmol) of the compound shown in formula (27).

[0575]

[0576] (In equation (27), r represents the average degree of polymerization, which is 2.5.)

[0577] Under a nitrogen atmosphere, 7.2 g of the compound of formula (27) (where r represents the average degree of polymerization of 2.5) , 0.67 g of potassium tert-butoxide, and 10.5 mL of tert-butanol were added to a 200 mL flask and stirred at room temperature until homogeneous. 2.60 g of the compound of formula (28) was then added to the homogeneous liquid, and the mixture was stirred at 70 °C for 16 hours to allow the reaction to proceed.

[0578] The compound shown in formula (28) was synthesized by oxidizing diallyl ether.

[0579]

[0580] After the reaction, the resulting 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 with anhydrous sodium sulfate. After filtration to separate the desiccant, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 5.9 g (molecular weight 728, 7.7 mmol) of the compound shown in formula (29).

[0581]

[0582] (In equation (29), r represents the average degree of polymerization, which is 2.5.)

[0583] Under a nitrogen atmosphere, 5.9 g of the compound of formula (29) (where r represents the average degree of polymerization of 2.5) , 0.12 g of potassium tert-butoxide, and 2.8 mL of tert-butanol were added to a 200 mL flask and stirred at room temperature until homogeneous. HOCH₂CF₂O(CF₂CF₂O) was then further added to this homogeneous liquid. r 1.6 g of the compound CF2CH2OH (where r represents the average degree of polymerization, which is 2.5) (number average molecular weight 468, molecular weight distribution 1.1) was reacted by stirring at 70 °C for 16 hours.

[0584] After the reaction, the resulting 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 filtration to separate the product with a drying agent, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 3.3 g (molecular weight 1812, 2.4 mmol) of the compound represented by formula (AN).

[0585]

[0586] (In formula (AN), Fpan1 and Fpan2 are represented by formula (ANF). In Fpan1, the pan representing the average degree of polymerization is 2.5, and in Fpan2, the pan representing the average degree of polymerization is 2.5.)

[0587] The resulting compound (AN) was subjected to... 1 H-NMR and 19 The structure was identified by F-NMR measurements, and the following results were obtained.

[0588] 1 H-NMR (CD3COCD3): δ [ppm] = 3.47~4.24 (50H)

[0589] 19 F-NMR (CD3COCD3): δ[ppm]=-78.6(6F), -81.3(6F), -90.0~-88.5(30F)

[0590] Substituting the compounds of Examples 1-20 and Comparative Examples 1-14 obtained in this manner into the R of Formula (1) 1 and R 7 The structure (e and f in equation (4-1), g and h in equation (4-2), i in equation (4-3), j in equation (4-4), and (4-5)), R 3 and R 5 The structure (a and b in equation (2), c and d in equation (3), R 2R 4 R 6 The structures (k and l in equation (5), m in equation (6), and n in equation (7)) are shown in Tables 1 to 2.

[0591] [Table 1]

[0592]

[0593] [Table 2]

[0594]

[0595] In addition, through the above 1 H-NMR and 19 The number-average molecular weights (Mn) of the compounds in Examples 1-20 and Comparative Examples 1-14 were determined by F-NMR spectroscopy. The results are shown in Table 3. It is also estimated that the average molecular weight of the synthesized compounds may vary by about 1 to 5 due to differences in the molecular weight distribution of the fluorinated polyethers used as raw materials and differences in the operation during compound synthesis.

[0596] [Table 3]

[0597]

[0598] Next, a lubricant layer forming solution was prepared using the compounds obtained in Examples 1-20 and Comparative Examples 1-14, according to the method shown below. Then, using the obtained lubricant layer forming solution, a lubricant layer of the magnetic recording medium was formed using the method shown below, thus obtaining the magnetic recording media of Examples 1-20 and Comparative Examples 1-14.

[0599] "Solution for forming a lubricating layer"

[0600] The compounds obtained in Examples 1-20 and Comparative Examples 1-14 were dissolved in fluorinated solvent, specifically fluorinated solvent, in a fluorinated solvent called fluorinated solvent XF (trade name, manufactured by Mitsui Dupont Fluorokemica Co., Ltd.), to determine the film thickness of the coating when applied to the protective layer. A solution for forming a lubricating layer was prepared by diluting it with Water Reel XF.

[0601] "Magnetic recording medium"

[0602] A magnetic recording medium was prepared on a substrate with a diameter of 65 mm, on which an adhesion layer, a soft magnetic layer, a first base layer, a second base layer, a magnetic layer, and a protective layer were sequentially disposed. The protective layer was formed of carbon with a thickness of 1–5 nm.

[0603] On the protective layer of the magnetic recording medium, which has formed layers up to the protective layer, the lubricating layer forming solutions of Examples 1-20 and Comparative Examples 1-14 were respectively applied by an impregnation method. The impregnation method was performed under the conditions of an impregnation speed of 10 mm / s, an impregnation time of 30 seconds, and a lifting speed of 1.2 mm / s.

[0604] Then, a polishing process was performed on the surface of the magnetic recording medium on which the lubricating layer was formed, using a polishing belt that maintained abrasive grains of size #6000.

[0605] The magnetic recording medium after polishing was placed in a constant temperature bath at 120°C and heated for 10 minutes for heat treatment.

[0606] Through the above processes, magnetic recording media (polished) of Examples 1-20 and Comparative Examples 1-14 were obtained.

[0607] In addition, without performing a polishing process, the magnetic recording media of Examples 1 to 20 and Comparative Examples 1 to 14 (unpolished) were obtained by operating in the same manner as polished magnetic recording media.

[0608] (Film thickness measurement)

[0609] The film thickness of the lubricating layer in the magnetic recording media (polished and unpolished) of Examples 1-20 and Comparative Examples 1-14 obtained by this operation was measured using a Fourier transform infrared spectrophotometer (FT-IR) (trade name: Nicolet iS50, manufactured by Thermo Fisher Scientific). There was no difference in the film thickness of the lubricating layer between polished and unpolished media in Examples 1-20 and Comparative Examples 1-14. The results are shown in Table 3.

[0610] Next, the polished and unpolished magnetic recording media of Examples 1-20 and Comparative Examples 1-14 were subjected to the following corrosion resistance tests.

[0611] (Corrosion resistance test)

[0612] The magnetic recording medium was exposed at 85°C and 90% relative humidity for 48 hours. Then, the number of corroded areas on the magnetic recording medium was counted using an optical surface analysis device, and the results were evaluated based on the following criteria. The results are shown in Table 3.

[0613] Evaluation Criteria

[0614] A: Less than 120

[0615] B: 120 or above and less than 150

[0616] C: 150 or higher and less than 350

[0617] D: 350 or higher but less than 1000

[0618] E: More than 1000

[0619] As shown in Table 3, the corrosion resistance test results of the magnetic recording media of Examples 1 to 20, which have a lubricating layer containing the compound shown in Formula (1), are A in the case of no polishing and A or B in the case of polishing with a polishing strip, indicating good corrosion resistance.

[0620] In contrast, the magnetic recording media of Comparative Examples 1 to 14 showed corrosion resistance results of C to E in both the case of unpolished and polished surfaces, indicating poorer corrosion resistance compared to the magnetic recording media of Examples 1 to 20.

[0621] More specifically, in the magnetic recording media of Examples 1-20, the lubricating layer comprises R in formula (1). 3 For equation (2) (where a is 2 and b is 1) and R 5 For equation (3) (where c is 2 and d is 1), or R 3 For equation (2) (where a is 3 and b is 1) and R 5 For equation (3) (where c is 3 and d is 1), R 1 and R 7 The compounds are those with terminal groups as shown in formulas (4-1) to (4-5). Therefore, compared with the magnetic recording media of Comparative Examples 1 to 14, the R of the compound in the lubricating layer of the magnetic recording media of Examples 1 to 20 is higher. 3 and R 5 It contains a large number of carbon atoms and has good hydrophobicity. Furthermore, this lubricating layer uses R... 1 and R 7 The carbon atoms bonded to the polar groups contained therein, and R 1 and R 7 The linker group in the lubricant layer exhibits appropriate hydrophobicity due to the hydrophobicity of the carbon atoms it contains. Furthermore, this lubricant layer utilizes R... 3 R 5 R 1 and R 7 Each component possesses a polar group, thereby achieving good adhesion with the protective layer. Based on these factors, it is presumed that for the magnetic recording media of Examples 1-20, good corrosion inhibition is achieved by preventing water from entering the lubricating layer from the outside.

[0622] Furthermore, the magnetic recording media of Examples 8-10, 13, 17, and 20 all achieved a corrosion resistance rating of A in both polished and unpolished conditions, demonstrating exceptionally excellent corrosion inhibition. This is presumably because the lubricating layer of the magnetic recording media of Examples 8-10, 13, 17, and 20 contains R. 3 For equation (2) (where a is 3 and b is 1), and R 5 For a compound of formula (3) (where c is 3 and d is 1), therefore the compound's R 3 and R 5 It contains more carbon atoms (longer methylene chain), resulting in better hydrophobicity.

[0623] For example, if R is used 1 and R 7 The terminal bases shown are the same, R 3 and R 5 The magnetic recording media of compounds with different linker groups shown were compared (Comparative Example 4 is compared to Examples 1 and 13; Comparative Example 2 is compared to Example 3; Comparative Examples 3, 11, and 12 are compared to Examples 5 and 17; Comparative Example 5 is compared to Example 16), then R 3 and R 5 The more carbon atoms it contains (the longer the methylene chain), the greater the corrosion inhibition effect.

[0624] In addition, R 1 and R 7 The magnetic recording media of Examples 3, 4, 7, 8, 11, 15, 19, and 20, whose terminal polar groups (4-1) and the connecting groups between the carbon atoms bonded to the terminal polar groups and the carbon atoms bonded to the adjacent polar groups do not contain ether bonds (-O-), exhibit good corrosion inhibition effects. This is presumably because the connecting groups contained in the terminal groups shown in Formulas (4-1) and (4-5) do not contain ether bonds but contain an appropriate number of carbon atoms, thus forming a lubricating layer with good hydrophobicity, preventing water intrusion.

[0625] In addition, R 1 and R 7The magnetic recording media of Examples 1, 2, 5, 6, 9, 10, 12-14, and 16-18, with end groups represented by formulas (4-2), (4-3), and (4-4) containing ether bonds between the carbon atoms bonded to the terminal polar groups and the carbon atoms bonded to the adjacent polar groups, exhibit good corrosion inhibition effects. This is presumably because the linking groups contained in the end groups represented by formulas (4-2), (4-3), and (4-4) contain an appropriate number of carbon atoms, thus forming a lubricating layer with good hydrophobicity, preventing water intrusion.

[0626] Furthermore, R in equation (1) 1 and R 7 Examples 2, 4, 7, 9-12, 14, 15, 18, and 20, each containing three hydroxyl groups, all achieved corrosion resistance test results of A with and without polishing, demonstrating exceptionally excellent corrosion inhibition effects. This can be attributed to the fact that R in formula (1)... 1 and R 7 The three hydroxyl groups contained in each component exhibit excellent adhesion to the protective layer. Excellent adhesion between the lubricating layer and the protective layer prevents water from penetrating into the lubricating layer from the outside.

[0627] In contrast, although R in Comparative Example 6 is different from R in Equation (1) 1 and R 7 Each has three hydroxyl groups, but the corrosion resistance test results are E (polished) and D (unpolished). This is presumably because, for the compound contained in the lubricating layer of the magnetic recording medium of Comparative Example 6, R in formula (1) 3 For equation (2) (where a is 1 and b is 1), and R 5 For equation (3) (where c is 1 and d is 1), and R 1 and R 7 The compound contains carbon atoms bonded to terminal hydroxyl groups and carbon atoms bonded to hydroxyl groups adjacent to the terminal hydroxyl groups. In a lubricating layer containing such a compound, since either the terminal hydroxyl group or the hydroxyl group adjacent to the terminal hydroxyl group is oriented in opposite directions relative to the protective layer, it is difficult to achieve a tight bond between the hydroxyl groups and the protective layer. Furthermore, a lubricating layer containing such a compound does not achieve sufficient hydrophobicity.

[0628] Furthermore, in equation (1) R 2 R 4 R 6Good corrosion resistance test results were obtained in Examples 1 to 10, which were PFPE chains selected from any one of Formula (5), Formula (6), and Formula (7), and in Examples 11 to 20, which were PFPE chains selected from two of Formula (5), Formula (6), and Formula (7).

[0629] Furthermore, R in equation (1) 3 For equation (2) (where a is 1 and b is 1), and R 5 For equation (3) (where c is 1 and d is 1), and R 1 In Comparative Examples 7 and 13, where the corrosion resistance was -OH, the corrosion resistance test results were both E. This is presumably because the hydrophobicity of the lubricating layer was insufficient, and R could not be adequately obtained. 1 The hydroxyl groups present result in poor adhesion of the protective layer and low coverage of the lubricating layer.

[0630] Industry availability

[0631] By using a lubricant for magnetic recording media containing the fluorinated ether compound of the present invention, a lubricating layer with high corrosion inhibition effect on the magnetic recording medium can be formed.

[0632] Explanation of symbols

[0633] 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 is represented by the following formula (1), R 1 -CH2-R 2 -CH2-R 3 -CH2-R 4 -CH2-R 5 -CH2-R 6 -CH2-R 7 (1) In equation (1), R 2 R 4 and R 6 For the same or different perfluoropolyether chains; R 3 R is the linking base shown in equation (2) below; 5 R is the linking base shown in equation (3) below; 1 and R 7 Each is an independent terminal group comprising two or three polar groups, each polar group being bonded to a different carbon atom, and the carbon atoms bonded to the polar groups being bonded to each other via a linker containing carbon atoms of unbonded polar groups; In equation (2), a is an integer from 1 to 3, and b is an integer from 1 to 2; in equation (3), c is an integer from 1 to 3, and d is an integer from 1 to 2; wherein, a in equation (2) and c in equation (3) are not both 1. Each of the polar groups is independently a hydroxyl group (-OH), an amino group (-NH2), a carboxyl group (-COOH), an aldehyde group (-COH), a carbonyl group (-CO-), or a sulfonyl group (-SO3H).

2. The fluorinated ether compound according to claim 1, wherein a in formula (2) is an integer of 2 to 3, and c in formula (3) is an integer of 2 to 3.

3. The fluorinated ether compound according to claim 1 or 2, wherein in formula (1), R 1 and R 7 All of its polar groups are hydroxyl groups.

4. The fluorinated ether compound according to claim 1 or 2, wherein in formula (1), -R 1 and -R 7 Each is an independent terminal base as shown in equations (4-1) to (4-5) below. In equation (4-1), e is an integer from 0 to 1, and f is an integer from 1 to 4; In equation (4-2), g is an integer from 1 to 2, and h is an integer from 1 to 3; In equation (4-3), i is an integer from 1 to 3; In equation (4-4), j is an integer from 1 to 2.

5. The fluorinated ether compound according to claim 1 or 2, wherein R in formula (1) 2 R 4 R 6 Each is independently any one of the following formulas (5) to (9). -CF2O-(CF2CF2O) k -(CF2O) l -CF2-(5) In equation (5), k and l represent the average degree of polymerization, each ranging from 0.1 to 20; -CF2O-(CF2CF2O) m -CF2-(6) In equation (6), m represents the average degree of polymerization, which ranges from 0.1 to 20. -CF2CF2O-(CF2CF2CF2O) n -CF2CF2-(7) In equation (7), n represents the average degree of polymerization, which ranges from 0.1 to 20; -CF2CF2CF2O-(CF2CF2CF2CF2O) o -CF2CF2CF2-(8) In equation (8), o represents the average degree of polymerization, which is 0.1 to 10; -CF(CF3)O-(CF2CF(CF3)O) p -CF(CF3)-(9) In equation (9), p represents the average degree of polymerization, which ranges from 0.1 to 20.

6. The fluorinated ether compound according to claim 1 or 2, wherein in formula (1), R 1 With R 7 same.

7. The fluorinated ether compound according to claim 1 or 2, wherein in formula (1), R 2 With R 6 same.

8. 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.

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, characterized in that, It is a magnetic recording medium on which at least a magnetic layer, a protective layer, and a lubricating layer are sequentially disposed on a substrate. 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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