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WO2017141775A1 - Liquide ionique, lubrifiant, et milieu d'enregistrement magnétique - Google Patents

Liquide ionique, lubrifiant, et milieu d'enregistrement magnétique Download PDF

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Publication number
WO2017141775A1
WO2017141775A1 PCT/JP2017/004451 JP2017004451W WO2017141775A1 WO 2017141775 A1 WO2017141775 A1 WO 2017141775A1 JP 2017004451 W JP2017004451 W JP 2017004451W WO 2017141775 A1 WO2017141775 A1 WO 2017141775A1
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Prior art keywords
general formula
acid
ionic liquid
stretching vibration
lubricant
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PCT/JP2017/004451
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English (en)
Japanese (ja)
Inventor
近藤　洋文
弘毅 初田
信郎 多納
パンカジュ バヘル
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Dexerials Corp
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Dexerials Corp
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Priority claimed from JP2016099590A external-priority patent/JP6663793B2/ja
Application filed by Dexerials Corp filed Critical Dexerials Corp
Priority to EP17753033.4A priority Critical patent/EP3418351A4/fr
Priority to US16/077,622 priority patent/US20190051326A1/en
Publication of WO2017141775A1 publication Critical patent/WO2017141775A1/fr
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/72—Protective coatings, e.g. anti-static or antifriction
    • G11B5/725—Protective coatings, e.g. anti-static or antifriction containing a lubricant, e.g. organic compounds
    • G11B5/7253—Fluorocarbon lubricant
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C215/00—Compounds containing amino and hydroxy groups bound to the same carbon skeleton
    • C07C215/02—Compounds containing amino and hydroxy groups bound to the same carbon skeleton having hydroxy groups and amino groups bound to acyclic carbon atoms of the same carbon skeleton
    • C07C215/40—Compounds containing amino and hydroxy groups bound to the same carbon skeleton having hydroxy groups and amino groups bound to acyclic carbon atoms of the same carbon skeleton with quaternised nitrogen atoms bound to carbon atoms of the carbon skeleton
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D207/00—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom
    • C07D207/02—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
    • C07D207/04—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having no double bonds between ring members or between ring members and non-ring members
    • C07D207/06—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having no double bonds between ring members or between ring members and non-ring members with radicals, containing only hydrogen and carbon atoms, attached to ring carbon atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D233/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings
    • C07D233/54—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members
    • C07D233/56—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring carbon atoms
    • C07D233/60—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring carbon atoms with hydrocarbon radicals, substituted by oxygen or sulfur atoms, attached to ring nitrogen atoms
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D295/00—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms
    • C07D295/04—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms with substituted hydrocarbon radicals attached to ring nitrogen atoms
    • C07D295/08—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms with substituted hydrocarbon radicals attached to ring nitrogen atoms substituted by singly bound oxygen or sulfur atoms
    • C07D295/084—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms with substituted hydrocarbon radicals attached to ring nitrogen atoms substituted by singly bound oxygen or sulfur atoms with the ring nitrogen atoms and the oxygen or sulfur atoms attached to the same carbon chain, which is not interrupted by carbocyclic rings
    • C07D295/088—Heterocyclic compounds containing polymethylene-imine rings with at least five ring members, 3-azabicyclo [3.2.2] nonane, piperazine, morpholine or thiomorpholine rings, having only hydrogen atoms directly attached to the ring carbon atoms with substituted hydrocarbon radicals attached to ring nitrogen atoms substituted by singly bound oxygen or sulfur atoms with the ring nitrogen atoms and the oxygen or sulfur atoms attached to the same carbon chain, which is not interrupted by carbocyclic rings to an acyclic saturated chain
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D487/00—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, not provided for by groups C07D451/00 - C07D477/00
    • C07D487/02—Heterocyclic compounds containing nitrogen atoms as the only ring hetero atoms in the condensed system, not provided for by groups C07D451/00 - C07D477/00 in which the condensed system contains two hetero rings
    • C07D487/04—Ortho-condensed systems
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M105/00—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound
    • C10M105/56—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound containing nitrogen
    • C10M105/70—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound containing nitrogen as ring hetero atom
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M105/00—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound
    • C10M105/72—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound containing sulfur, selenium or tellurium

Definitions

  • the present invention relates to an ionic liquid, a lubricant containing the ionic liquid, and a magnetic recording medium using the same.
  • a lubricant is applied to the surface of the magnetic layer in order to reduce friction and wear on the magnetic head and the medium surface.
  • the actual film thickness of the lubricant is at the molecular level in order to avoid adhesion such as stiction. Therefore, in thin film magnetic recording media, it is no exaggeration to say that the most important thing is the selection of a lubricant having excellent wear resistance under all circumstances.
  • the lubricant be present on the surface of the medium without causing desorption, spin-off, chemical degradation, and the like.
  • the presence of the lubricant on the medium surface becomes more difficult as the surface of the thin film magnetic recording medium becomes smoother. This is because the thin film magnetic recording medium does not have a lubricant replenishment capability unlike the coating type magnetic recording medium.
  • the lubricant film thickness decreases during heating and sliding, which accelerates wear and requires a large amount of lubricant. It is said. A large amount of lubricant becomes a mobile lubricant and can have a function of replenishing the lost lubricant. However, the excess lubricant makes the film thickness of the lubricant larger than the surface roughness, causing problems related to adhesion, and in the fatal case, it becomes a stiction and causes drive failure. There is.
  • Non-Patent Document 1 the increase rate of the in-plane recording density of the product hard disk drive has been decreasing for the past several years, but it has achieved an annual rate of 25%, which is one target of 4Tb. / In 2 is about to arrive.
  • FIG. 2 it can be seen that the distance between the head disk interfaces is decreasing with the increase in recording density, but there is always a need to improve the reliability. This is described, for example, in Non-Patent Documents 2 to 4 below.
  • the current recording density is about 1 Tb / in 2
  • the spacing is about 6 nm
  • the lubricant thickness is 0.8 nm.
  • the thickness of the lubricant must be reduced. Don't be.
  • PFPE perfluoropolyether
  • a new lubricant is molecularly designed and synthesized in order to eliminate these trade-offs.
  • Many reports on the lubricity of PFPE have been submitted.
  • the lubricant is very important in the magnetic recording medium.
  • Table 1 shows the chemical structure of a typical PFPE lubricant.
  • Z-DOL in Table 1 is one of the commonly used lubricants for thin film magnetic recording media.
  • Z-tetraol (ZTMD) is one in which a functional hydroxyl group is further introduced into the main chain of PFPE, and it has been reported that the reliability of the drive is improved while reducing the gap in the head media interface.
  • A20H suppresses decomposition of the PFPE main chain by Lewis acid or Lewis base and improves tribological properties.
  • Mono has a report that the polymer main chain and the polar group are polynormalpropyloxy and amine, respectively, unlike the above-mentioned PFPE, and reduce the adhesion interaction in the near contact.
  • the liquid lubricant has mobility such that the lubricant removed by abrasion by the head moves from the adjacent lubricant layer and is replenished.
  • the disk spins off during disk operation and lubricant is reduced, resulting in a loss of protection.
  • a high-viscosity and low-volatile lubricant is suitably used, and the evaporation rate can be suppressed and the life of the disk drive can be extended.
  • requirements for low friction and low wear lubricants used in thin film magnetic recording media are as follows. (1) Low volatility. (2) Low surface tension for the surface replenishment function. (3) There is an interaction between the terminal polar group and the disk surface. (4) High thermal and oxidative stability so that there is no decomposition or decrease during the period of use. (5) It is chemically inert to metals, glass, and polymers and does not generate wear powder on the head or guide. (6) There must be no toxicity or flammability. (7) Excellent boundary lubrication characteristics. (8) Dissolve in an organic solvent.
  • ionic liquids are attracting attention as one of the environmentally friendly solvents for synthesizing organic and inorganic materials in power storage materials, separation technologies, and catalyst technologies.
  • Ionic liquids fall into the large category of low melting point molten salts, but generally, those having a melting point of 100 ° C. or lower among them.
  • Important characteristics of ionic liquids used as lubricants include low volatility, lack of flammability, thermal stability, and excellent dissolution performance.
  • friction and wear on the metal or ceramic surface may be reduced by using a certain ionic liquid as compared with a conventional hydrocarbon-based lubricant.
  • a certain ionic liquid as compared with a conventional hydrocarbon-based lubricant.
  • an imidazole cation-based ionic liquid substituted with a fluoroalkyl group is synthesized, and alkyl imidazolium tetrafluoroborate or hexafluorophosphate can be used for steel, aluminum, copper, single crystal SiO 2 , silicon, sialon ceramics ( When used for Si—Al—O—N), it has been reported that it exhibits superior tribological properties over cyclic phosphazene (X-1P) and PFPE.
  • Non-Patent Document 5 reports an imidazole-based tris (pentafluoroethyl) trifluorophosphate ionic liquid, but only shows the possibility, and does not mention specific tribological characteristics.
  • perfluorooctanoic acid alkylammonium salt is a protonic ionic liquid (PIL), but it has been reported that it has a remarkable effect of reducing friction of magnetic recording media as compared with Z-DOL described above.
  • PIL protonic ionic liquid
  • these perfluorocarboxylic acid ammonium salts have a weak cation-anion interaction in the reaction shown in the following reaction formula (A), and the equilibrium is on the left at high temperatures due to Le Chatelier's law. , It becomes a dissociated neutral compound and the thermal stability is deteriorated. That is, proton transfer occurs at a high temperature, and the equilibrium moves to a neutral substance and dissociates (see, for example, Non-Patent Document 9). That is, the thermal stability at a high temperature is deteriorated.
  • the limit of the surface recording density of the hard disk is said to be 1-2.5 Tb / in 2 .
  • the limit is approaching, but energetic development of high-capacity technology has been continued on the premise of miniaturization of magnetic particles. Technologies for increasing the capacity include reduction of effective flying height, introduction of single write (BMP), and the like.
  • FIG. 3 shows an outline of the heat-assisted magnetic recording.
  • reference numeral 1 indicates laser light
  • reference numeral 2 indicates near-field light
  • reference numeral 3 indicates a recording head (PMR element)
  • reference numeral 4 indicates a reproducing head (TMR element).
  • PMR element recording head
  • TMR element reproducing head
  • the protic ionic liquid is generally a substance having high thermal stability in order to form ions as described above.
  • the equilibrium is shown in the following Scheme 1.
  • HA represents a Bronsted acid
  • B represents a Bronsted base.
  • the acid (HA) and the base (B) react to form a salt (A ⁇ HB + ) as shown in Scheme 1.
  • the dissociation constants K a1 and K b2 of the acid and the base can be expressed as the following Scheme 2 in a form including the concentration.
  • the difference ⁇ pKa in acid dissociation constant between acid and base will be discussed.
  • the acid / base reaction is influenced by the acidity / basicity of each other (or the acidity of the conjugate acid), and the acidity difference ⁇ pKa can be expressed together in the following Scheme 3.
  • Non-Patent Documents 12 and 13 Regarding the heat resistance of ionic liquids reports that the decomposition temperature rises to a certain extent, but the decomposition temperature does not increase so much even if ⁇ pKa is increased beyond that. (See Non-Patent Documents 12 and 13).
  • a pyrrolidinium-based ionic liquid having a geminal dication may improve heat resistance as compared with a normal monocation ionic liquid (see Non-Patent Document 13).
  • Non-Patent Document 14 the relationship between the molecular structure constituting the structure and physical or chemical properties is not well understood. The combination of cation and anion greatly affects the physical or chemical properties of the ionic liquid.
  • the anion moiety is rich in variability, but the relationship is not clear unless it is a structurally similar cation (see, for example, Non-Patent Document 15).
  • the stronger the hydrogen bonding force of halogen (Cl>Br> I), the more viscous the liquid.
  • the method for increasing the viscosity is not limited to this, and it is possible, for example, by changing the alkyl chain of imidazole.
  • it affects melting point, surface tension, and thermal stability, but the effect of its anion has not been studied extensively. Therefore, it is possible to change these physical or chemical properties by a combination of cation and anion, but it is difficult to predict.
  • a polar group such as a hydroxyl group is introduced at the end in order to enhance the interaction with the media surface.
  • a hydroxyl group reacts with the surface of the medium and is fixed by heat treatment to improve thermal stability, and also has an effect of lowering the polar term component of the surface energy by bonding with the hydroxyl group (Non-patent Document 16). ).
  • the ionic liquid lubricant preferably has a lower melting point when considering uses other than hard disks.
  • the present invention has been proposed in view of such a conventional situation, and has an excellent lubricity even at a high temperature and can be lowered in melting point, so that it can be applied to various purposes.
  • the present invention provides a lubricant that has excellent lubricity even at a high temperature and can be applied to various purposes because of a low melting point, and a magnetic recording medium having excellent practical characteristics.
  • ⁇ 1> containing an ionic liquid having a conjugate base and a conjugate acid
  • the conjugate acid has a group containing a hydroxyl group and a group containing a linear hydrocarbon group having 6 or more carbon atoms;
  • the lubricant is characterized in that the pKa in acetonitrile of the acid which is the base of the conjugate base is 10 or less.
  • R 1, and R 2 represents independently a hydrogen atom, and one of the group carbon atoms containing 6 or more straight chain hydrocarbon radical, n Represents an integer of 1 or more. However, at least one of R 1 and R 2 is a group containing a linear hydrocarbon group having 6 or more carbon atoms. However, in said general formula (B), R represents group containing a C6 or more linear hydrocarbon group, and n represents an integer greater than or equal to 1. However, in said general formula (C), R represents group containing a C6 or more linear hydrocarbon group, and n represents an integer greater than or equal to 1.
  • R represents a group containing a straight chain hydrocarbon group having 6 or more carbon atoms
  • R 1, and R 2 are each independently a hydrogen atom
  • n represents an integer of 1 or more.
  • l represents an integer of 1-12.
  • l represents the integer of 1-12.
  • a magnetic material comprising a nonmagnetic support, a magnetic layer on the nonmagnetic support, and the lubricant according to any one of ⁇ 1> to ⁇ 3> on the magnetic layer. It is a recording medium.
  • ⁇ 5> having a conjugate base and a conjugate acid,
  • the conjugate acid has a group containing a hydroxyl group and a group containing a linear hydrocarbon group having 6 or more carbon atoms; It is an ionic liquid characterized in that the pKa in acetonitrile of the acid that is the base of the conjugate base is 10 or less.
  • the conjugate acid according to ⁇ 5> wherein the conjugate acid is represented by any one of the following general formula (A), the following general formula (B), the following general formula (C), and the following general formula (D). It is an ionic liquid.
  • the general formula (A), R 1, and R 2 represents independently a hydrogen atom, and one of the group carbon atoms containing 6 or more straight chain hydrocarbon radical, n Represents an integer of 1 or more.
  • at least one of R 1 and R 2 is a group containing a linear hydrocarbon group having 6 or more carbon atoms.
  • R represents group containing a C6 or more linear hydrocarbon group, and n represents an integer greater than or equal to 1.
  • R represents group containing a C6 or more linear hydrocarbon group, and n represents an integer greater than or equal to 1.
  • the general formula (D) R represents a group containing a straight chain hydrocarbon group having 6 or more carbon atoms, R 1, and R 2 are each independently a hydrogen atom, and hydrocarbon Represents one of hydrogen groups, and n represents an integer of 1 or more.
  • l represents an integer of 1-12.
  • l represents the integer of 1-12.
  • an ionic liquid that has excellent lubricity even at a high temperature and can be applied to various purposes because it can have a low melting point, has an excellent lubricity even at a high temperature, and low Since the melting point can be increased, it is possible to provide a lubricant that can be applied to various purposes and a magnetic recording medium having excellent practical characteristics.
  • FIG. 1 is a graph showing the transition and prediction of the in-plane recording density of a hard disk drive.
  • FIG. 2 is a road map of head media spacing (HMS) with respect to the in-plane recording density of the hard disk.
  • FIG. 3 is a schematic diagram showing heat-assisted magnetic recording.
  • FIG. 4 is a cross-sectional view showing an example of a hard disk according to an embodiment of the present invention.
  • FIG. 5 is a cross-sectional view showing an example of a magnetic tape according to an embodiment of the present invention.
  • the lubricant shown as one embodiment of the present invention contains an ionic liquid having a conjugate acid and a conjugate base.
  • the ionic liquid shown as one embodiment of the present invention has a conjugate acid and a conjugate base.
  • the conjugate acid has a group containing a hydrocarbon group.
  • the hydrocarbon group is a linear hydrocarbon group having 6 or more carbon atoms.
  • the “linear hydrocarbon group having 6 or more carbon atoms” may be a partially fluorinated hydrocarbon group in which a part of hydrogen atoms bonded to carbon is substituted with a fluorine atom.
  • the conjugate acid has a group containing a hydroxyl group.
  • the pKa in acetonitrile of the acid serving as the base of the conjugate base is 10 or less.
  • the ionic liquid in this embodiment has a conjugate acid and a conjugate base, and the pKa in acetonitrile of the acid that is the base of the conjugate base is 10 or less, and therefore exhibits excellent thermal stability. be able to. Since the cationic part has a group containing a hydrocarbon group having 6 or more carbon atoms, it can have excellent lubricating properties. Moreover, since a hydroxyl group was introduced into the cation moiety, the heat resistance and solubility in a fluorinated solvent were improved, and the melting point was lowered.
  • Some compounds have improved solubility in CF 3 (CHF) 2 CF 2 CF 3 , which is often used as a fluorinated solvent in hard disk lubricant coating processes, resulting in explosion-proof production lines for magnetic recording media There is no need to make specifications.
  • the lubricant containing the ionic liquid may be used at a concentration of about 0.05% by mass of the ionic liquid. Therefore, the solubility of the ionic liquid in the fluorine-based solvent is preferably 0.05% by mass or more. Further, depending on the use situation, higher solubility may be required.
  • the pKa is a strong acid of 10 or less, and preferably 6.0 or less.
  • the lower limit of the pKa is not particularly limited and may be appropriately selected depending on the intended purpose. However, the pKa is preferably ⁇ 5.0 or more.
  • pKa in the present specification is an acid dissociation constant, which is an acid dissociation constant in acetonitrile.
  • the conjugate base is not particularly limited as long as the pKa in acetonitrile of the original acid is 10 or less, and can be appropriately selected according to the purpose.
  • the conjugate base is represented by the following general formula (X).
  • the conjugate base represented by the following general formula (X) and the conjugate base represented by the following general formula (Y) are preferable in that the solubility of the ionic liquid in the solvent can be increased.
  • l represents an integer of 1 to 12 and is preferably an integer of 1 to 6.
  • l represents the integer of 1-12, and an integer of 1-6 is preferable.
  • the conjugate acid has a group containing a linear hydrocarbon group having 6 or more carbon atoms, and further has a group containing a hydroxyl group.
  • the method for introducing a hydroxyl group into the conjugate acid is not particularly limited.
  • One example of this method employs a method of alkylating a nitrogen atom of a conjugate acid using a halide as described in the following examples. Therefore, the introduction method is completely different from Z-DOL and Z-Tetraol, which are general perfluoropolyether lubricants, and the method is not helpful.
  • the conjugate acid has a group containing a linear hydrocarbon group having 6 or more carbon atoms.
  • the number of carbon atoms of the hydrocarbon group is not particularly limited as long as it is 6 or more, and can be appropriately selected according to the purpose, but is preferably 10 or more.
  • the upper limit of the carbon number of the linear hydrocarbon group having 6 or more carbon atoms is not particularly limited and may be appropriately selected depending on the purpose. From the viewpoint of procurement of raw materials, the carbon number Is preferably 30 or less, more preferably 25 or less, and particularly preferably 20 or less.
  • the group containing a linear hydrocarbon group having 6 or more carbon atoms is preferably a linear hydrocarbon group having 6 or more carbon atoms.
  • the carbon number of the hydrocarbon group is determined in consideration of the effect of reducing the friction coefficient and the solubility in a solvent.
  • the hydrocarbon group may be linear, and may be either a saturated hydrocarbon group, an unsaturated hydrocarbon group partially having a double bond, or an unsaturated branched hydrocarbon group partially having a branch. Good.
  • an alkyl group which is a saturated hydrocarbon group is preferable from the viewpoint of wear resistance.
  • hydrocarbon group examples include a group represented by the following general formula (I) and a group represented by the following general formula (II).
  • l represents an integer of 5 or more, preferably an integer of 9 to 29, more preferably an integer of 9 to 24, and particularly preferably an integer of 9 to 19.
  • m represents an integer of 1 to 6, and n represents an integer of 3 to 20. However, m + n is 7 or more.
  • m is preferably an integer of 1 to 3, and n is preferably an integer of 5 to 10.
  • the conjugate acid has a group containing a hydroxyl group.
  • the group containing a hydroxyl group include a group represented by the following general formula (IV). — (CH 2 ) n —OH Formula (IV)
  • n is an integer of 1 or more, preferably an integer of 1 to 10, and more preferably an integer of 1 to 6.
  • conjugate acid a conjugate acid represented by the following general formula (A), a conjugate acid represented by the following general formula (B), a conjugate acid represented by the following general formula (C), and the following general formula (
  • the conjugate acid represented by D) is preferable in terms of heat resistance and lubrication characteristics.
  • the general formula (A), R 1, and R 2 represents independently a hydrogen atom, and one of the group carbon atoms containing 6 or more straight chain hydrocarbon radical, n Represents an integer of 1 or more.
  • at least one of R 1 and R 2 is a group containing a linear hydrocarbon group having 6 or more carbon atoms.
  • R represents group containing a C6 or more linear hydrocarbon group, and n represents an integer greater than or equal to 1.
  • R represents group containing a C6 or more linear hydrocarbon group, and n represents an integer greater than or equal to 1.
  • R represents a group containing a straight chain hydrocarbon group having 6 or more carbon atoms
  • R 1, and R 2 are each independently a hydrogen atom
  • n represents an integer of 1 or more.
  • it is 6 or more, there is no restriction
  • the upper limit of the carbon number of the hydrocarbon group is not particularly limited and may be appropriately selected depending on the intended purpose. From the viewpoint of procurement of raw materials, the carbon number is preferably 30 or less, and 25 or less. More preferred is 20 or less.
  • the hydrocarbon group is a long chain, the friction coefficient can be reduced and the lubrication characteristics can be improved.
  • the said C6 or more linear hydrocarbon group is preferable.
  • the carbon number of the hydrocarbon group is determined in consideration of the effect of reducing the friction coefficient and the solubility in a solvent.
  • the R 1 and R 2 in the general formula (A), the R in the general formula (B), the R in the general formula (C), and the hydrocarbon group in the R in the general formula (D). May be a straight chain, and may be a saturated hydrocarbon group, an unsaturated hydrocarbon group partially having a double bond, or an unsaturated branched hydrocarbon group partially having a branch.
  • an alkyl group which is a saturated hydrocarbon group is preferable from the viewpoint of wear resistance.
  • Examples of the R 1 and R 2 in the general formula (A), the R in the general formula (B), the R in the general formula (C), and the R in the general formula (D) include: Examples include groups represented by the following general formula (III). — (CH 2 ) 1 —CH 3 General Formula (III) In the general formula (III), l represents an integer of 5 or more, preferably an integer of 9 or more and 29 or less, and more preferably an integer of 9 or more and 19 or less.
  • R 1 and R 2 in the general formula (D) are hydrocarbon groups, the carbon number thereof is not particularly limited and may be appropriately selected depending on the intended purpose. 10 is preferable, and 1 to 6 carbon atoms is more preferable.
  • N is an integer of 1 or more, preferably an integer of 1 to 10, and more preferably an integer of 1 to 6.
  • conjugate acid represented by the general formula (A) examples include conjugate acids represented by the following general formula (A-1).
  • R represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, and n represents an integer of 1 or more.
  • an ionic liquid represented by the following general formula (1) As the ionic liquid, an ionic liquid represented by the following general formula (1), an ionic liquid represented by the following general formula (2), an ionic liquid represented by the following general formula (3), and the following general formula (4) The ionic liquid represented by this is preferable.
  • a ⁇ represents a conjugate base
  • R 1 and R 2 each independently represent a hydrogen atom and a linear hydrocarbon group having 6 or more carbon atoms. Any one of the groups to be included, and n represents an integer of 1 or more. However, at least one of R 1 and R 2 is a group containing a linear hydrocarbon group having 6 or more carbon atoms.
  • a - represents a conjugate base
  • R represents the number of carbon atoms represents a group containing 6 or more straight chain hydrocarbon group
  • n is an integer of 1 or more .
  • a ⁇ represents a conjugate base
  • R represents a group containing a linear hydrocarbon group having 6 or more carbon atoms
  • R 1 and R 2 are respectively Independently, it represents either a hydrogen atom or a hydrocarbon group
  • n represents an integer of 1 or more.
  • an ionic liquid represented by the general formula (1) an ionic liquid represented by the following general formula (1-1) and an ionic liquid represented by the following general formula (1-2) are preferable.
  • R 1 and R 2 each independently represent either a hydrogen atom or a group containing a linear hydrocarbon group having 6 or more carbon atoms.
  • N represents an integer of 1 or more
  • l represents an integer of 1 to 12.
  • at least one of R 1 and R 2 is a group containing a linear hydrocarbon group having 6 or more carbon atoms.
  • R 1 and R 2 each independently represent either a hydrogen atom or a group containing a linear hydrocarbon group having 6 or more carbon atoms.
  • N represents an integer of 1 or more
  • l represents an integer of 1 to 12.
  • at least one of R 1 and R 2 is a group containing a linear hydrocarbon group having 6 or more carbon atoms.
  • an ionic liquid represented by the general formula (2) an ionic liquid represented by the following general formula (2-1) and an ionic liquid represented by the following general formula (2-2) are preferable.
  • an ionic liquid represented by the following general formula (2-2) is more preferable from the viewpoint of excellent solubility in a fluorine-based solvent.
  • R represents a group containing a linear hydrocarbon group having 6 or more carbon atoms
  • n represents an integer of 1 or more
  • l represents 1 to 12 Represents the following integers:
  • R represents a group containing a linear hydrocarbon group having 6 or more carbon atoms
  • n represents an integer of 1 or more
  • l represents 1 or more and 12 Represents the following integers:
  • Examples of the ionic liquid represented by the general formula (3) include an ionic liquid represented by the following general formula (3-1) and an ionic liquid represented by the following general formula (3-2). It is preferable at the point which is excellent in the solubility to.
  • R represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, n represents an integer of 1 or more, and l represents 1 or more and 12 Represents the following integers:
  • R represents a group containing a linear hydrocarbon group having 6 or more carbon atoms, n represents an integer of 1 or more, and l represents 1 or more and 12 Represents the following integers:
  • Examples of the ionic liquid represented by the general formula (4) include an ionic liquid represented by the following general formula (4-1) and an ionic liquid represented by the following general formula (4-2). It is preferable at the point which is excellent in the solubility to.
  • R represents a group containing a linear hydrocarbon group having 6 or more carbon atoms
  • R 1 and R 2 are each independently a hydrogen atom
  • n represents an integer of 1 or more
  • l represents an integer of 1 or more and 12 or less.
  • R represents a group containing a linear hydrocarbon group having 6 or more carbon atoms
  • R 1 and R 2 are each independently a hydrogen atom
  • n represents an integer of 1 or more
  • l represents an integer of 1 or more and 12 or less.
  • the preferable range of R in the general formula of the ionic liquid is the same as the preferable range of R in the general formula of the corresponding conjugate acid.
  • R 1 and R 2 in the ionic liquid represented by the general formula (1), the ionic liquid represented by the general formula (1-1), and the ionic liquid represented by the general formula (1-2) are preferable.
  • the range is the same as the preferable range of R 1 and R 2 of the conjugate acid represented by the corresponding general formula (A).
  • R 1 and R 2 in the ionic liquid represented by the general formula (4), the ionic liquid represented by the general formula (4-1), and the ionic liquid represented by the general formula (4-2) are preferable.
  • the range is the same as the preferable range of R 1 and R 2 of the conjugate acid represented by the corresponding general formula (D).
  • the preferable range of n in the general formula of the ionic liquid is the same as the preferable range of n of the corresponding general formula of the conjugate acid.
  • the preferable range of l in the general formula of the ionic liquid is the same as the preferable range of l of the corresponding general formula of the conjugate base.
  • the above-described ionic liquid may be used alone or in combination with a conventionally known lubricant.
  • it can be used in combination with long chain carboxylic acid, long chain carboxylic acid ester, perfluoroalkyl carboxylic acid ester, carboxylic acid perfluoroalkyl ester, perfluoroalkyl carboxylic acid perfluoroalkyl ester, perfluoropolyether derivative, etc. Is possible.
  • an extreme pressure agent may be used in combination at a mass ratio of about 30:70 to 70:30.
  • the extreme pressure agent acts to prevent friction and wear by forming a reaction product film by reacting with the metal surface due to frictional heat generated when metal contact occurs partially in the boundary lubrication region.
  • the extreme pressure agent for example, any of a phosphorus extreme pressure agent, a sulfur extreme pressure agent, a halogen extreme pressure agent, an organometallic extreme pressure agent, a composite extreme pressure agent, and the like can be used.
  • the rust inhibitor may be any rust inhibitor that can be used as a rust inhibitor for this type of magnetic recording medium.
  • the rust preventive agent may be used as a lubricant, but a magnetic layer is formed on a nonmagnetic support, a rust preventive layer is applied thereon, and then a lubricant layer is applied. Thus, it may be applied in two or more layers.
  • solvent for the lubricant for example, alcohol solvents such as isopropyl alcohol (IPA) and ethanol can be used alone or in combination.
  • IPA isopropyl alcohol
  • ethanol can be used by mixing a hydrocarbon solvent such as normal hexane or a fluorine solvent.
  • a fluorine-based solvent is preferable.
  • fluorine-based solvent examples include hydrofluoroethers [for example, C 3 F 7 OCH 3 , C 4 F 9 OCH 3 , C 4 F 9 OC 2 H 5 , C 2 F 5 CF (OCH 3 ) C 3 F 7 , CF 3 (CHF) 2 CF 2 CF 3 ], etc., and alcohols such as IPA, ethanol or methanol may be used in combination.
  • the fluorinated solvent may be a commercially available product. Examples of the commercially available products include Novec TM 7000, 7100, 7200, 7300, 71IPA manufactured by 3M, Vertrel XF, X-P10 manufactured by Mitsui DuPont Fluorochemical Co., Ltd., and the like.
  • a magnetic recording medium shown as an embodiment of the present invention has at least a magnetic layer on a nonmagnetic support, and the magnetic layer contains the above-mentioned lubricant.
  • the lubricant in the present embodiment can be applied to a so-called metal thin film type magnetic recording medium in which a magnetic layer is formed on the surface of a nonmagnetic support by a technique such as vapor deposition or sputtering.
  • the present invention can also be applied to a magnetic recording medium having a configuration in which an underlayer is interposed between a nonmagnetic support and a magnetic layer. Examples of such a magnetic recording medium include a magnetic disk and a magnetic tape.
  • FIG. 4 is a cross-sectional view showing an example of a hard disk.
  • This hard disk has a structure in which a substrate 11, an underlayer 12, a magnetic layer 13, a carbon protective layer 14, and a lubricant layer 15 are sequentially laminated.
  • FIG. 5 is a cross-sectional view showing an example of a magnetic tape.
  • This magnetic tape has a structure in which a backcoat layer 25, a substrate 21, a magnetic layer 22, a carbon protective layer 23, and a lubricant layer 24 are sequentially laminated.
  • the nonmagnetic support corresponds to the substrate 11 and the underlayer 12, and in the magnetic tape shown in FIG. 5, the nonmagnetic support corresponds to the substrate 21.
  • a rigid substrate such as an Al alloy plate or a glass plate
  • an oxide film such as an alumite treatment or Ni-P film may be formed on the substrate surface to harden the surface. Good.
  • the magnetic layers 13 and 22 are formed as a continuous film by a technique such as plating, sputtering, vacuum deposition, or plasma CVD.
  • the magnetic layers 13 and 22 include metals such as Fe, Co, Ni, Co—Ni alloys, Co—Pt alloys, Co—Ni—Pt alloys, Fe—Co alloys, Fe—Ni alloys, In-plane magnetization recording metal magnetic film made of Fe—Co—Ni alloy, Fe—Ni—B alloy, Fe—Co—B alloy, Fe—Co—Ni—B alloy, etc., Co—Cr alloy Examples thereof include perpendicular magnetic recording metal magnetic thin films such as thin films and Co—O thin films.
  • a nonmagnetic material such as Bi, Sb, Pb, Sn, Ga, In, Ge, Si, or Tl is previously formed on the nonmagnetic support as the underlayer 12.
  • metal magnetic materials are vapor-deposited or sputtered from the vertical direction, and these non-magnetic materials are diffused in the magnetic metal thin film to eliminate orientation and ensure in-plane isotropy and improve coercive force. You may do it.
  • hard protective layers 14 and 23 such as a carbon film, a diamond-like carbon film, a chromium oxide film, and a SiO 2 film may be formed on the surfaces of the magnetic layers 13 and 22.
  • the top surface of the magnetic layers 13 and 22 or the surface of the protective layers 14 and 23 is used.
  • the method of coating is mentioned.
  • the coating amount of the lubricant is preferably 0.1 mg / m 2 to 100 mg / m 2 , more preferably 0.5 mg / m 2 to 30 mg / m 2 , and 0.5 mg / m 2 to Particularly preferred is 20 mg / m 2 .
  • a back coat layer 25 may be formed as necessary.
  • the back coat layer 25 is formed by adding a carbon-based fine powder for imparting conductivity to the resin binder and an inorganic pigment for controlling the surface roughness.
  • the aforementioned lubricant may be added to the back coat layer 25 by internal addition or top coat. Further, the above-described lubricant may be added to both the magnetic layer 22 and the back coat layer 25 by internal addition or top coat.
  • the lubricant can be applied to a so-called coating type magnetic recording medium in which a magnetic coating film is formed as a magnetic layer by applying a magnetic paint to the surface of a nonmagnetic support. is there.
  • a coating type magnetic recording medium any conventionally known magnetic powder, resin binder and the like constituting the nonmagnetic support, the magnetic coating film, and the like can be used.
  • the nonmagnetic support for example, a polymer support formed of a polymer material typified by polyesters, polyolefins, cellulose derivatives, vinyl resins, polyimides, polyamides, polycarbonates and the like. Examples thereof include metal substrates made of aluminum alloy, titanium alloy, etc., ceramics substrates made of alumina glass, etc., glass substrates, and the like.
  • the shape is not limited at all, and any shape such as a tape shape, a sheet shape, or a drum shape may be used.
  • the non-magnetic support may be subjected to a surface treatment so as to form fine irregularities in order to control the surface property.
  • the magnetic powder examples include ferromagnetic iron oxide particles such as ⁇ -Fe 2 O 3 and cobalt-coated ⁇ -Fe 2 O 3 , ferromagnetic chromium dioxide particles, metals such as Fe, Co, Ni, and the like. Examples thereof include ferromagnetic metal particles made of an alloy containing hexagonal plate-like ferrite fine particles.
  • the resin binder examples include vinyl chloride, vinyl acetate, vinyl alcohol, vinylidene chloride, acrylic acid ester, methacrylic acid ester, styrene, butadiene, acrylonitrile, or a combination of these two or more, polyurethane Resins, polyester resins, epoxy resins and the like are exemplified.
  • a hydrophilic polar group such as a carboxylic acid group, a carboxyl group or a phosphoric acid group may be introduced in order to improve the dispersibility of the magnetic powder.
  • a dispersant In addition to the magnetic powder and the resin binder, a dispersant, an abrasive, an antistatic agent, an antirust agent, and the like may be added to the magnetic coating film as an additive.
  • Examples of a method for retaining the lubricant in such a coating type magnetic recording medium include a method of internally adding the magnetic layer constituting the magnetic coating film formed on the nonmagnetic support, There is a method of top-coating the surface of the layer, or a combination of both.
  • the lubricant is internally added to the magnetic coating film, it is added in the range of 0.2 to 20 parts by mass with respect to 100 parts by mass of the resin binder.
  • the coating amount is preferably 0.1 mg / m 2 to 100 mg / m 2 , and 0.5 mg / m 2 to 20 mg / m 2. 2 is more preferable.
  • an ionic liquid is dissolved in a solvent, and the obtained solution is applied or sprayed, or a magnetic recording medium is immersed in this solution.
  • the magnetic recording medium to which the lubricant in the present embodiment is applied exhibits excellent running performance, wear resistance, durability, and the like due to the lubricating action, and can further improve the thermal stability.
  • Example> Hereinafter, specific examples of the present invention will be described.
  • an ionic liquid was synthesized to produce a lubricant containing the ionic liquid.
  • Bertrell CF 3 (CHF) 2 CF 2 CF 3
  • the lubricant solution was applied to the surfaces of a magnetic disk and a magnetic tape, and the disk durability and tape durability were evaluated, respectively.
  • the production of the magnetic disk, the disk durability test, the production of the magnetic tape, and the tape durability test were performed as follows. The present invention is not limited to these examples.
  • a magnetic thin film was formed on a glass substrate to produce a magnetic disk as shown in FIG. Specifically, a chemically strengthened glass disk made of aluminum silicate glass with an outer diameter of 65 mm, an inner diameter of 20 mm, and a disk thickness of 0.635 mm is prepared, and the surface is polished so that Rmax is 4.8 nm and Ra is 0.43 nm. did.
  • the glass substrate was subjected to ultrasonic cleaning in pure water and isopropyl alcohol (IPA) having a purity of 99.9% or more for 5 minutes each, left in IPA saturated vapor for 1.5 minutes and then dried. did.
  • IPA isopropyl alcohol
  • a NiAl alloy Ni: 50 mol%, Al: 50 mol%) thin film is formed as a seed layer by DC magnetron sputtering, and a CrMo alloy (Cr: 80 mol%, Mo: 20 mol) is used as the underlayer 12. %)
  • a thin film having a thickness of 8 nm and a CoCrPtB alloy (Co: 62 mol%, Cr: 20 mol%, Pt: 12 mol%, B: 6 mol%) as a magnetic layer 13 were sequentially formed to a thickness of 15 nm.
  • a carbon protective layer 14 made of amorphous diamond-like carbon is formed to 5 nm by plasma CVD, and the disk sample is ultrasonicated in isopropyl alcohol (IPA) having a purity of 99.9% or more for 10 minutes in a cleaner. Cleaning was performed to remove impurities on the disk surface, and then drying was performed. After that, the lubricant layer 15 was formed to have a thickness of about 1 nm by applying it to the disk surface by a dip coating method using a mixed solvent of ionic liquid n-hexane and ethanol in an environment of 25 ° C. and 50% relative humidity (RH).
  • IPA isopropyl alcohol
  • TG / DTA measurement EXSTAR6000 manufactured by Seiko Instruments Inc. is used, and measurement is performed in a temperature range of 30 ° C-600 ° C at a temperature increase rate of 10 ° C / min while introducing air at a flow rate of 200 ml / min. went. The endothermic peak temperature in the measurement was taken as the melting point.
  • ⁇ Disk durability test> Using a commercially available strain gauge type disk friction and wear tester, after mounting the hard disk on the rotating spindle with a tightening torque of 14.7 Ncm, the center of the air bearing surface on the inner circumference side of the hard disk of the head slider is A head slider was mounted on the hard disk so as to be 17.5 mm from the center, and a CSS durability test was conducted.
  • the head used in this measurement is an IBM 3370 type inline head, the material of the slider is Al 2 O 3 —TiC, and the head load is 63.7 mN.
  • the maximum value of the frictional force was monitored for each CSS (Contact, Start, Stop) in an environment of clean cleanliness 100 and 25 ° C. 60% RH.
  • the number of times the friction coefficient exceeded 1.0 was taken as the result of the CSS durability test.
  • “> 50,000” was displayed.
  • the CSS durability test after performing the heat test for 3 minutes at the temperature of 200 degreeC was similarly done.
  • a magnetic tape having a cross-sectional structure as shown in FIG. 5 was produced.
  • Co was deposited on a substrate 21 made of a Toray Mikutron (aromatic polyamide) film having a thickness of 5 ⁇ m by an oblique deposition method to form a magnetic layer 22 made of a ferromagnetic metal thin film having a thickness of 100 nm.
  • a carbon protective layer 23 made of 10 nm diamond-like carbon was formed on the surface of the ferromagnetic metal thin film by plasma CVD, and then cut to a width of 6 mm.
  • An ionic liquid dissolved in IPA was applied onto the carbon protective layer 23 so as to have a film thickness of about 1 nm to form a lubricant layer 24, thereby preparing a sample tape.
  • ⁇ Tape durability test> About each sample tape, the still durability under a temperature of -5 ° C and a temperature of 40 ° C and 30% RH, and the friction coefficient and shuttle durability under a temperature of -5 ° C and a temperature of 40 ° C and 90% RH. Measurements were made. For the still durability, the decay time until the output in the pause state decreased by -3 dB was evaluated. Shuttle durability was evaluated by the number of shuttles until the output decreased by 3 dB after repeatedly running the shuttle for 2 minutes each time. Moreover, in order to investigate heat resistance, the durability test after performing the heat test for 10 minutes at the temperature of 100 degreeC was similarly done.
  • the ionic liquid in the present embodiment has a conjugate base and a conjugate acid, and the pKa in acetonitrile of the acid serving as the base of the conjugate base is 10 or less. Furthermore, it is preferable that the conjugate acid (cation moiety) has a group containing a hydrocarbon group having 6 or more carbon atoms and a hydroxyl group. The influence on the thermal stability of such an ionic liquid and the durability of a magnetic recording medium using the ionic liquid was investigated. Furthermore, the solubility in a fluorinated solvent was examined.
  • Example 1A Synthesis of Nonafluorobutanesulfonic Acid-1- 'Hydroxypropyl-3-octadecylimidazolium> Synthesis of nonafluorobutanesulfonic acid-1-3′hydroxylpropyl-3-octadecylimidazolium was performed according to the following scheme.
  • 1-octadecyl imidazole was obtained by dissolving 3 g of imidazole in 100 mL of acetonitrile, adding 14.9 g of octadecyl bromide and 2.51 g of potassium hydroxide, heating the mixture with stirring, and refluxing for 4 hours. After removing the solvent, the mixture was extracted with dichloromethane and purified by column chromatography. When analyzed by gas chromatography, the purity was 98.5% or more.
  • the product was identified as bis (nonafluorobutanesulfonyl) imide 1-3′hydroxylpropyl-3-octadecylimidazolium.
  • the pKa in acetonitrile of the acid [bis (nonafluorobutanesulfonyl) imide], which is the base of the conjugate base in bis (nonafluorobutanesulfonyl) imide 1-3′hydroxylpropyl-3-octadecylimidazolium, in the acetonitrile is 0. 0.
  • Bromooctadecane 52.4 g and potassium hydroxide 8.75 g were added to acetonitrile, and pyrrolidine 11.09 g was added. Thereafter, heating under reflux was performed for 24 hours. After filtering the crystals, the solvent of the organic layer was removed and the residue was purified by silica gel column chromatography using a mixed solvent of hexane and ethyl acetate to obtain 44.05 g of octadecylpyrrolidine. The purity by gas chromatography was 99.0% or more.
  • Octadecylpyrrolidine (6.00 g) and 3-bromopropanol (3.23 g) were added to the flask and heated at 120 ° C. for 3.0 hours. After returning to room temperature, ethyl acetate was added for crystallization to obtain 7.77 g of N-3'hydroxylpropyl-N-octadecylpyrrolidinium bromide. Yield 90.5%.
  • the product was identified as bis (nonafluorobutanesulfonyl) imide-N-3′hydroxylpropyl-N-octadecylpyrrolidinium.
  • pKa in acetonitrile of the acid [bis (nonafluorobutanesulfonyl) imide], which is the base of the conjugate base in bis (nonafluorobutanesulfonyl) imide-N-3′hydroxylpropyl-N-octadecylpyrrolidinium, 0.0.
  • 6-Octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene is a non-patent document [N. Matsumura, H.M. Nishiguchi, M. Okada, and S. Yoneda, J.A. Heterocyclic Chem. Pp. 885-887, Vol / 23. Synthesized according to Issue 3 (1986)].
  • 6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecenium 5.71 g and 3-bromopropanol 3.23 g were added to the flask and heated at 120 ° C. for 3.0 hours. After returning to normal temperature, ethyl acetate was added to dissolve the reaction product, which was then crystallized in a freezer. The crystals were quickly filtered at a low temperature and then vacuum-dried to obtain 6.60 g of 6-octadecyl-8-3'-hydroxylpropyl-1,8-diazabicyclo [5.4.0] -7-undecenium bromide. Yield 81.9%.
  • 1134 cm ⁇ 1 is a SO 2 -bonded symmetric stretching vibration
  • 1255 cm ⁇ 1 is a CF 2 symmetric stretching vibration
  • 1352 cm ⁇ 1 is an SO 2 -bonded symmetric stretching vibration
  • 1466 cm ⁇ 1 is a CH 2 bending vibration
  • 1609 cm ⁇ 1 C N stretching vibration
  • 2855 cm ⁇ 1 symmetric CH 2 stretching vibration 2926 cm ⁇ 1 CH 2 inverse symmetric stretching vibration
  • 3479 cm ⁇ 1 hydroxyl group stretching vibration 3479 cm ⁇ 1 hydroxyl group stretching vibration.
  • nonafluorobutanesulfonic acid-6-octadecyl-8-3′-hydroxylpropyl-1,8-diazabicyclo [5.4.0] -7-undecenium is a base acid for the conjugate base (nonafluorobutanesulfonic acid).
  • PKa in acetonitrile is 0.7.
  • 6-octadecyl-8-3′-hydroxylpropyl-1,8-diazabicyclo [5.4.0] -7-undecenium bromide (2.04 g) synthesized in Example 4A was dissolved by heating pure water, A solution in which 3.07 g of potassium bis (nonafluorobutanesulfonyl) imide was dissolved by heating pure water and ethanol was added, reacted at room temperature for 1 hour, and then heated to reflux for 1 hour. After cooling, the reaction solution was extracted with dichloromethane, and the organic layer was washed with pure water until the AgNO 3 test became negative.
  • 1-octadecyl-2-heptadecylimidazole is prepared by dissolving 15.34 g of 2-heptadecylimidazole in 100 mL of toluene, adding 17.62 g of octadecyl bromide and 4.86 g of potassium hydroxide, and heating with stirring. And obtained by refluxing for 11 hours. After removing the solvent, the mixture was extracted with dichloromethane and purified by silica gel column chromatography using a solution of n-hexane: ethyl acetate 9: 1. Analysis by gas chromatography revealed a purity of 99.3% or more.
  • the product was identified as bis (nonafluorobutanesulfonyl) imide 1-3′hydroxylpropyl-2-heptadecyl-3-octadecylimidazolium.
  • pKa in acetonitrile of the acid [bis (nonafluorobutanesulfonyl) imide] which is the base of the conjugate base in bis (nonafluorobutanesulfonyl) imide 1-3′hydroxyl-2-heptadecyl-3-octadecylimidazolium Is 0.0.
  • N, N-dimethyltetradecylamine 6.83 g and 3-bromopropanol 5.80 g were put in a closed flask and reacted at 90 ° C. for 5 hours. When the temperature was returned to room temperature after the completion of the reaction, it became a viscous liquid. When n-hexane was added thereto, a precipitate was deposited. Decanted and the supernatant was discarded. This operation was performed three times to purify the product, and 9.50 g of N, N-dimethyl-N-3'hydroxypropyltetradecylammonium bromide was obtained. Yield 89.2%.
  • the product was identified as bis (nonafluorobutanesulfonyl) imide-N-3′hydroxypropyl-N, N-dimethyltetradecylammonium. It should be noted that pKa of bis (nonafluorobutanesulfonyl) imide-N-3′hydroxypropyl-N, N-dimethyltetradecylammonium as the base of the conjugate base [bis (nonafluorobutanesulfonyl) imide] in acetonitrile Is 0.0.
  • N, N-dimethyloctadecylamine 8.71 g and 3-bromopropanol 4.19 g were placed in a closed flask and reacted at 120 ° C. for 2 hours. Crystals precipitated after returning to room temperature were recrystallized from a mixed solvent of ethyl acetate and ethanol to obtain 11.28 g of N-3'hydroxypropyl-N, N-dimethyloctadecylammonium bromide. Yield 88.2%.
  • Example 4A To an ethanol solution of 6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene synthesized in Example 4A (4.04 g) was added 5.00 g of heptadecafluorooctanesulfonic acid, and the mixture was stirred at room temperature for 1 hour. Thereafter, heating under reflux was performed for 1 hour. After removing the solvent, it was dissolved in dichloromethane and washed thoroughly with water. The organic layer was dried over anhydrous sodium sulfate, and then the solvent was removed.
  • 6-octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene synthesized in Example 4A was added to an ethanol solution of 2.18 g of hexafluorocyclopropane-1,3-bis (sulfonyl) imide (3.00 g). After stirring at room temperature for 1 hour, the mixture was heated to reflux for 1 hour. After removing the solvent, it was dissolved in dichloromethane and washed thoroughly with water. The organic layer was dried over anhydrous sodium sulfate, and then the solvent was removed. Vacuum drying at 90 ° C.
  • nonafluorobutanesulfonic acid-1-octadecyl-2-heptadecylimidazolium was synthesized.
  • Hexafluorocyclopropane-1,3-bis (sulfonyl) imide-1-octadecyl-2-heptadecylimidazolium Hexafluorocyclopropane-1,3-bis (sulfonyl) imide-1-octadecyl-2-heptadecylimidazolium, a base acid of a conjugate base [hexafluorocyclopropane-1,3-bis (sulfonyl) imide PKa in acetonitrile is -0.8.
  • Octadecylamine was dissolved in ethanol, and an equimolar amount of an ethanol solution of bis (nonafluorobutanesulfonyl) imide was added. Heating under reflux was performed for 1 hour, and the solvent was removed after cooling. The residue was extracted with dichloromethane and the organic layer was washed thoroughly with water. After drying over anhydrous sodium sulfate, the solvent is removed and recrystallization is performed from a mixed solvent of n-hexane and ethanol to obtain colorless crystals of bis (nonafluorobutanesulfonyl) imide-octadecylammonium. Yield 91.1%.
  • the product was identified as bis (nonafluorobutanesulfonyl) imide-octadecylammonium.
  • the product was identified as nonafluorobutanesulfonic acid-N, N, N-trimethyloctadecyl ammonium.
  • the pKa in acetonitrile of the acid (nonafluorobutanesulfonic acid) that is the base of the conjugate base in nonafluorobutanesulfonic acid-N, N, N-trimethyloctadecylammonium is 0.7.
  • Example 1B to 5B, and Comparative Examples 1B to 5B, Comparative Example 10B, and Comparative Example 11B ⁇ Measurement results of solubility in fluorine-based solvents> Vertrel XF [CF 3 (CHF) 2 CF 2 CF manufactured by Mitsui DuPont Fluoro Chemical Co., Ltd.] as a fluorinated solvent for the ionic liquids synthesized in each Example and each Comparative Example, and Z-DOL and Z-TETRAOL 3 ] was used to conduct a solubility test.
  • Vertrel XF CF 3 (CHF) 2 CF 2 CF manufactured by Mitsui DuPont Fluoro Chemical Co., Ltd.
  • ionic liquid, Z-DOL and Z-TETRAOL were added to a predetermined mass of Bertrell XF, respectively, irradiated with ultrasonic waves for 5 minutes, and allowed to stand for 1 day, and its solubility was visually confirmed. Specifically, 1.0 parts by weight, 0.5 parts by weight, and 0.1 parts by weight of ionic liquid, and Z-DOL and Z-TETRAOL are added to 100 parts by weight of Bertrell XF (25 ° C.). After being left for 1 day after being irradiated with ultrasonic waves for 5 minutes, its solubility was visually confirmed and evaluated according to the following evaluation criteria.
  • the solubility of the ionic liquid of Example 1A in the fluorinated solvent was less than 0.1% by mass.
  • the solubility of the ionic liquid of Example 2A in the fluorine-based solvent was 0.1% by mass or more and less than 0.5% by mass.
  • the solubility of the ionic liquid of Example 3A in the fluorine-based solvent was 0.5% by mass or more.
  • the solubility of the ionic liquid of Example 4A in the fluorinated solvent was 0.1% by mass or more and less than 0.5% by mass.
  • the solubility of the ionic liquid of Example 5A in the fluorine-based solvent was 0.1% by mass or more and less than 0.5% by mass.
  • the solubility of the ionic liquids of Comparative Examples 1A to 5A in the fluorine-based solvent was less than 0.1% by mass.
  • the solubility of Z-DOL and Z-TETRAOL in a fluorine-based solvent was 0.5% by mass or more.
  • the ionic liquids used in the examples have improved solubility in the fluorinated solvent Bartrel XF.
  • the compounds of Examples 2A-5A are sufficient for use in production for hard disk applications.
  • Example 2B As can be seen from Comparative Example 1B and Comparative Example 2B, the imidazole-based ionic liquid has low solubility in Vertrel, but it can be seen that Example 2B into which hydroxyl groups have been introduced has improved solubility. That is, it can be seen that introduction of a hydroxyl group as a molecular design method is effective for solubility in vertell.
  • Example 3A having bis (nonafluorobutanesulfonyl) imide as an anion. Even in the case of having the same octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene skeleton, Comparative Examples 3B and 4B have low solubility in Vertrel but are improved in Examples 4B and 5B. ing.
  • Example 6B to Example 10B and Comparative Example 6B to Comparative Example 11B ⁇ Solubility measurement results in solvent> Vertrel XF [CF 3 (CHF) 2 CF 2 manufactured by Mitsui DuPont Fluoro Chemical Co., Ltd.] as a fluorinated solvent for the ionic liquids synthesized in the examples and comparative examples, and Z-DOL and Z-TETRAOL) CF 3 ], and a reagent-grade n-hexane and ethanol manufactured by Junsei Chemical Co., Ltd. were used for the solubility test.
  • Vertrel XF CF 3 (CHF) 2 CF 2 manufactured by Mitsui DuPont Fluoro Chemical Co., Ltd.
  • Z-DOL and Z-TETRAOL Z-DOL and Z-TETRAOL
  • An ionic liquid was added to a predetermined mass of Bertrell XF, n-hexane, or ethanol, and the mixture was allowed to stand for 1 day after being irradiated with ultrasonic waves for 5 minutes, and its solubility was visually confirmed. Specifically, 0.2 parts by mass of an ionic liquid is added to 100 parts by mass of Bertrell XF (25 ° C.), irradiated with ultrasonic waves for 5 minutes, and left for 1 day, and then its solubility is visually checked. Confirmed and evaluated according to the following evaluation criteria.
  • ⁇ n-hexane and ethanol >> ⁇ 0.5% by mass or more: It dissolves by addition of 0.5 part by mass. -Less than 0.5% by mass: The addition of 0.5 part by mass is insoluble.
  • the solubility of the ionic liquid of Example 6A in the fluorine-based solvent is 0.2% by mass or more, the solubility in n-hexane is 0.5% by mass or more, and the solubility in ethanol is 0.5% by mass or more. there were.
  • the solubility of the ionic liquid of Example 7A in a fluorine-based solvent is 0.2% by mass or more, the solubility in n-hexane is 0.5% by mass or more, and the solubility in ethanol is 0.5% by mass or more. there were.
  • the solubility of the ionic liquid of Example 8A in the fluorine-based solvent is 0.2% by mass or more, the solubility in n-hexane is 0.5% by mass or more, and the solubility in ethanol is 0.5% by mass or more. there were.
  • the solubility of the ionic liquid of Example 9A in a fluorine-based solvent is 0.2% by mass or more, the solubility in n-hexane is 0.5% by mass or more, and the solubility in ethanol is 0.5% by mass or more. there were.
  • the solubility of the ionic liquid of Example 10A in the fluorine-based solvent is 0.2% by mass or more, the solubility in n-hexane is 0.5% by mass or more, and the solubility in ethanol is 0.5% by mass or more. there were.
  • the solubility of the ionic liquids of Comparative Examples 6A to 9A in ethanol was 0.5% by mass or more, the solubility in a fluorine-based solvent was less than 0.2% by mass, and the solubility in n-hexane The solubility was less than 0.5% by mass.
  • the ionic liquid of Comparative Example 5A had a solubility in a fluorine-based solvent of less than 0.2% by mass, but the solubility in n-hexane and ethanol was 0.5% by mass or more.
  • the solubility of Z-DOL and Z-TETRAOL in a fluorine-based solvent was 0.2% by mass or more, but the solubility in n-hexane and ethanol was less than 0.5% by mass.
  • the ionic liquid using the sulfonate shown in the comparative example as a raw material has poor solubility in fluorine and hydrocarbon solvents, although it is a sulfonate having the same polarity. It can be seen that the solubility of the example sulfonate ionic liquid is greatly improved. Taking into account that the material widely used as a lubricant is a long-chain fatty acid or an ester thereof, dissolving in hexane means that the effect as an additive can be exhibited from the compatibility. Further, since it dissolves in the fluoric solvent Vertrel XF, it is sufficient for use in production as a micromachine or a hard disk. Comparative Examples 10B and 11B having a perfluoropolyether skeleton have high solubility in a fluorine solvent, but their use is limited because of their low solubility in hydrocarbon solvents or alcohols.
  • the solubility the influence of the molecular structure is very complicated and difficult to predict.
  • the imidazole ionic liquid is low in solubility in bartrel or n-hexane in the imidazole ionic liquid having a long alkyl chain, as can be seen from Comparative Example 6B and Comparative Example 7B.
  • the solubility was improved in Examples 6B and 7B into which a hydroxyl group was introduced.
  • ammonium-based lubricants have poor solubility with sulfonates or sulfoimide salts, but it is also found that the solubility is improved by the introduction of hydroxyl groups. That is, it can be seen that introduction of a hydroxyl group as a molecular design method is effective for solubility in Vertrel or n-hexane.
  • Example 1C ⁇ Thermal stability measurement result> The 5%, 10% and 20% weight loss temperatures of nonafluorobutanesulfonic acid 1-3′hydroxylpropyl-3-octadecylimidazolium are 307.7 ° C., 357.2 ° C. and 388.2 ° C., respectively.
  • a commercially available perfluoropolyether Z-DOL (Comparative Example 10C), which is generally known as a lubricant for magnetic recording media, shown as a comparative example, 140 ° C. or higher, and Z-TETRAOL (Comparative Example 11C) ) And 60 ° C. or higher.
  • Example 2C ⁇ Thermal stability measurement result> The 5%, 10%, and 20% weight loss temperatures of bis (nonafluorobutanesulfonyl) imide 1-3′hydroxylpropyl-3-octadecylimidazolium are 327.7 ° C., 361.7 ° C., and 389.3 ° C., respectively. there were. It can be seen that the thermal stability is improved by 150 ° C. and 90 ° C. or more, respectively, as compared with commercially available perfluoropolyether Z-DOL (Comparative Example 10C) and Z-TETRAOL (Comparative Example 11C).
  • Example 3C ⁇ Thermal stability measurement result> The 5%, 10% and 20% weight loss temperatures of bis (nonafluorobutanesulfonyl) imide-N-3′hydroxylpropyl-N-octadecylpyrrolidinium were 349.8 ° C., 370.8 ° C. and 387.6 respectively. ° C. Even when compared with commercially available perfluoropolyether Z-DOL (Comparative Example 10C) and Z-TETRAOL (Comparative Example 11C), it can be seen that the thermal stability is improved by 160 ° C. and 100 ° C. or more, respectively.
  • Example 4C ⁇ Thermal stability measurement result> Nonafluorobutanesulfonic acid-6-octadecyl-8-3′-hydroxylpropyl-1,8-diazabicyclo [5.4.0] -7-undecenium 5%, 10%, 20% It was 0.0 degreeC, 356.5 degreeC, and 390.1 degreeC. It can be seen that the thermal stability is improved by 160 ° C. and 85 ° C. or more, respectively, as compared with commercially available perfluoropolyether Z-DOL (Comparative Example 10C) and Z-TETRAOL (Comparative Example 11C).
  • Example 5C ⁇ Thermal stability measurement result> The 5%, 10%, and 20% weight loss temperatures of bis (nonafluorobutanesulfonyl) imide-6-octadecyl-8-3′-hydroxylpropyl-1,8-diazabicyclo [5.4.0] -7-undecenium are The temperature was 326.2 ° C., 360.8 ° C., and 387.7 ° C., respectively. It can be seen that the thermal stability is improved by 160 ° C. and 85 ° C. or more, respectively, as compared with commercially available perfluoropolyether Z-DOL (Comparative Example 10C) and Z-TETRAOL (Comparative Example 11C).
  • Example 6C ⁇ Thermal stability measurement result> The 5%, 10%, and 20% weight loss temperatures of 1-dodecyl-2-undecyl-3-'hydroxypropylimidazolium nonafluorobutanesulfonate were 335.4 ° C, 368.6 ° C, 396.2 ° C, respectively.
  • a commercially available perfluoropolyether Z-DOL (Comparative Example 10C), which is generally known as a lubricant for magnetic recording media, shown as a comparative example, is 170 ° C. or higher, and Z-TETRAOL Even if it compares with (Comparative Example 11C), it turns out that it is 90 degreeC or more higher.
  • Example 7C ⁇ Thermal stability measurement result> The 5%, 10%, and 20% weight loss temperatures of bis (nonafluorobutanesulfonyl) imido-1-dodecyl-2-undecyl-3-'hydroxylpropyloctadecylimidazolium were 350.9 ° C and 373.7 ° C, respectively. It was 394.8 degreeC. Even when compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 10C) and Z-TETRAOL (Comparative Example 11C), it can be seen that the thermal stability is improved by 170 ° C. and 110 ° C. or more, respectively.
  • Example 8C ⁇ Thermal stability measurement result>
  • the 5%, 10%, and 20% weight loss temperatures of bis (nonafluorobutanesulfonyl) imide-1- 3'hydroxypropyl-2-heptadecyl-3-octadecylimidazolium are 327.8 ° C, 364.3 ° C, respectively.
  • the temperature was 398.8 ° C. It can be seen that the thermal stability is improved by 160 ° C. and 85 ° C. or more, respectively, as compared with commercially available perfluoropolyether Z-DOL (Comparative Example 10C) and Z-TETRAOL (Comparative Example 11C).
  • Example 9C Thermal stability measurement result>
  • the 5%, 10%, and 20% weight loss temperatures of bis (nonafluorobutanesulfonyl) imide-N-3′hydroxypropyl-N, N-dimethyltetradecylammonium were 340.0 ° C., 359.0 ° C., 375 respectively. 0 ° C. It can be seen that the thermal stability is improved at 145 ° C. and 90 ° C. or more, respectively, as compared with the commercially available perfluoropolyether Z-DOL (Comparative Example 10C) and Z-TETRAOL (Comparative Example 11C).
  • Example 10C ⁇ Thermal stability measurement result> The 5%, 10%, and 20% weight loss temperatures of bis (nonafluorobutanesulfonyl) imide-N-3′hydroxypropyl-N, N-dimethyloctadecylammonium were 336.5 ° C., 359.4 ° C., and 376. It was 6 ° C. It can be seen that the thermal stability is improved by 150 ° C. and 90 ° C. or more, respectively, as compared with commercially available perfluoropolyether Z-DOL (Comparative Example 10C) and Z-TETRAOL (Comparative Example 11C).
  • Comparative Example 10C ⁇ Thermal stability measurement result>
  • a commercially available perfluoropolyether Z-DOL having a hydroxyl group at the terminal and having a molecular weight of about 2000 was measured.
  • the 5%, 10%, and 20% weight loss temperatures were 165.0 ° C., 197.0 ° C., 226.0 ° C.
  • the weight loss is attributed to evaporation.
  • Z-TETRAOL Perfluoropolyether having a molecular weight of about 2000 and having a plurality of hydroxyl groups at the terminals, which is a commercially available product and is generally used as a lubricant for magnetic recording media, was used as the lubricant of Comparative Example 11C.
  • the 5%, 10%, and 20% weight loss temperatures of Z-TETRAOL are 240.0 ° C., 261.0 ° C., and 282.0 ° C., respectively.
  • the weight loss is caused by evaporation.
  • the ionic liquid lubricant is overwhelmingly superior in thermal stability as compared with the commercially available perfluoropolyethers of Comparative Examples 10C and 11C, except for Comparative Example 5C.
  • the ionic liquid about thermal stability
  • group ionic liquid In Examples into which hydroxyl groups were introduced, the weight loss temperatures of 5% and 10% were lower than those of the Comparative Examples, but the weight loss temperatures of 20% were almost the same, and it is considered that they had sufficient thermal stability.
  • the pyrrolidine ionic liquid into which the hydroxyl group is introduced also exhibits almost the same thermal stability as the imidazole ionic liquid.
  • Examples having an octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene structure can be compared from Examples 3C and 4C and Comparative Examples 3C and 4C. In this case as well, the weight reduction temperature is higher in the comparative example of about 20 ° C to 430 ° C.
  • an ionic liquid having an octadecyl-1,8-diazabicyclo [5.4.0] -7-undecene structure has a considerably high weight loss temperature, and the 20% weight loss temperature is close to 390 ° C., so that it has sufficient thermal stability. It is considered to have Further, in Examples 6C to 10C, the weight reduction temperature does not change much compared with Comparative Examples 6C to 9C, and is almost the same, and is considered to have sufficient thermal stability.
  • the melting point there is a great reduction effect by introducing a hydroxyl group. That is, the ionic liquid shown in the comparative example is a solid at 25 ° C. because it has a long-chain alkyl group. However, all ionic liquids having a hydroxyl group introduced and having bis (nonafluorobutanesulfonyl) imide as a conjugate base are liquid at room temperature. In the case of imidazole having the sulfonic acid of Example 1A as a conjugate base, the melting point is lower than that of the comparative example.
  • the low melting point of the lubricant is advantageous in that the application can be greatly expanded in addition to the hard disk. For example, it can be expected that high-efficiency production with a liquid-type lubricant is realized in high-temperature extrusion / high-temperature forging (Non-Patent Document: Tribology Society 2014 Spring, Proceedings).
  • Example 1D to 10D and Comparative Examples 1D to 4D and Comparative Examples 6D to 9D ⁇ Disk durability test>
  • Lubricants containing the respective ionic liquids of Examples 1A to 10A, Comparative Examples 1A to 4A, and Comparative Examples 6A to 9A were applied to produce magnetic disks. As shown in Table 4, the CSS measurement of the magnetic disk exceeded 50,000 times, and the CSS measurement after the heating test exceeded 50,000 times, indicating excellent durability.
  • Table 4 summarizes the results of Example 1D to Example 10D and Comparative Example 1D to Comparative Example 11D.
  • Example 1E to Example 10E Comparative Example 1E to Comparative Example 11E
  • the magnetic tapes described above were prepared using the ionic liquids of Examples 1A to 10A, the ionic liquids of Comparative Examples 1A to 9A, Z-DOL, and Z-Tetraol, the following measurements were performed. It was.
  • Friction coefficient of magnetic tape after 100 times of shuttle operation Temperature -5 °C or 40 °C, relative humidity 90% ⁇ Still endurance test -5 °C or 40 °C relative Under 30% humidity environment ⁇ Shuttle endurance test -5 ° C environment or 40 ° C temperature, 90% relative humidity environment ⁇ Coefficient of friction of magnetic tape after 100 shuttle runs after heating test Environment or temperature 40 ° C, relative humidity 90% • Still durability test after heating test Temperature ⁇ 5 ° C environment or temperature 40 ° C, relative humidity 30% environment • Shuttle durability test after heating test Temperature Under an environment of -5 ° C or under a temperature of 40 ° C and relative humidity of 90%
  • an ionic liquid having a conjugated base and a conjugated acid is contained, and the conjugated acid is a group containing a linear hydrocarbon group having 6 or more carbon atoms and a hydroxyl group.
  • an ionic liquid lubricant having a pKa in acetonitrile of the base acid of the conjugate base of 10 or less excellent heat resistance and durability in magnetic tape and magnetic disk are obtained.
  • the heat resistance and durability of the magnetic recording medium excellent, but some of them also dissolve in the vertebral solvent bartrel, so when considering the application of hard disks in particular, the manufacturing process can be improved. But there is no problem.
  • the ionic liquid lubricant having pKa in acetonitrile of 10 or less of the acid that is the base of the conjugate base has a high decomposition temperature, 5%, 10%, and 20% weight loss temperature, and is thermally stable. Excellent. In addition, excellent lubricity can be maintained even under high temperature conditions as compared with conventional perfluoropolyethers, and lubricity can be maintained over a long period of time. Therefore, the magnetic recording medium using the lubricant containing the ionic liquid can obtain very excellent running performance, wear resistance, and durability.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Lubricants (AREA)
  • Magnetic Record Carriers (AREA)

Abstract

La présente invention concerne un lubrifiant contenant un liquide ionique présentant une base conjuguée et un acide conjugué. L'acide conjugué possède un groupe comprenant un groupe hydroxyle et un groupe comprenant un groupe hydrocarboné linéaire ayant six atomes de carbone ou plus, et l'acide qui devient la source pour la base conjuguée a une valeur de pKa inférieure ou égale à 10 dans l'acétonitrile.
PCT/JP2017/004451 2016-02-15 2017-02-07 Liquide ionique, lubrifiant, et milieu d'enregistrement magnétique Ceased WO2017141775A1 (fr)

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