WO2001065549A1 - Support d'enregistrement magnetique et procede de production correspondant - Google Patents

Support d'enregistrement magnetique et procede de production correspondant Download PDF

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Publication number
WO2001065549A1
WO2001065549A1 PCT/JP2001/001421 JP0101421W WO0165549A1 WO 2001065549 A1 WO2001065549 A1 WO 2001065549A1 JP 0101421 W JP0101421 W JP 0101421W WO 0165549 A1 WO0165549 A1 WO 0165549A1
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WO
WIPO (PCT)
Prior art keywords
layer
recording medium
lubricant
magnetic recording
magnetic
Prior art date
Application number
PCT/JP2001/001421
Other languages
English (en)
Japanese (ja)
Inventor
Yukikazu Ohchi
Yasuharu Shinokawa
Yasuhiro Nishizawa
Original Assignee
Matsushita Electric Industrial Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co., Ltd. filed Critical Matsushita Electric Industrial Co., Ltd.
Publication of WO2001065549A1 publication Critical patent/WO2001065549A1/fr

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Classifications

    • 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
    • G11B5/7257—Perfluoropolyether lubricant
    • 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
    • C10M111/00—Lubrication compositions characterised by the base-material being a mixture of two or more compounds covered by more than one of the main groups C10M101/00 - C10M109/00, each of these compounds being essential
    • C10M111/02—Lubrication compositions characterised by the base-material being a mixture of two or more compounds covered by more than one of the main groups C10M101/00 - C10M109/00, each of these compounds being essential at least one of them being a non-macromolecular organic compound
    • 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
    • C10M105/50—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound containing halogen
    • 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
    • C10M111/00—Lubrication compositions characterised by the base-material being a mixture of two or more compounds covered by more than one of the main groups C10M101/00 - C10M109/00, each of these compounds being essential
    • C10M111/04—Lubrication compositions characterised by the base-material being a mixture of two or more compounds covered by more than one of the main groups C10M101/00 - C10M109/00, each of these compounds being essential at least one of them being a macromolecular organic compound
    • 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
    • C10M2211/00—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions
    • C10M2211/04—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions containing carbon, hydrogen, halogen, and oxygen
    • C10M2211/042—Alcohols; Ethers; Aldehydes; Ketones
    • C10M2211/0425—Alcohols; Ethers; Aldehydes; Ketones used as base material
    • 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
    • C10M2211/00—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions
    • C10M2211/04—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions containing carbon, hydrogen, halogen, and oxygen
    • C10M2211/044—Acids; Salts or esters thereof
    • C10M2211/0445—Acids; Salts or esters thereof used as base material
    • 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
    • C10M2213/00—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
    • C10M2213/04—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions obtained from monomers containing carbon, hydrogen, halogen and oxygen
    • C10M2213/043—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions obtained from monomers containing carbon, hydrogen, halogen and oxygen used as base material
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2040/00—Specified use or application for which the lubricating composition is intended
    • C10N2040/14—Electric or magnetic purposes
    • C10N2040/18—Electric or magnetic purposes in connection with recordings on magnetic tape or disc

Definitions

  • the present invention relates to a magnetic recording medium, and more particularly to a metal thin film type magnetic recording medium having a ferromagnetic metal thin film suitable for high density magnetic recording as a magnetic layer.
  • a magnetic recording medium constituted by such a method is generally called a metal thin film type magnetic recording medium or a high density magnetic recording medium.
  • Another method that satisfies the above requirements is to make the magnetic recording medium thinner so that more magnetic recording media can be accommodated in a package of a predetermined size. According to this method, resource saving, low cost, and other effects are also brought.
  • the most effective way to reduce the thickness of a magnetic recording medium is to reduce the thickness of a non-magnetic substrate, which accounts for most of the thickness of the magnetic recording medium.
  • the rigidity of the magnetic recording medium decreases, which may cause a practical problem. Therefore, for example, Japanese Patent Application Laid-Open Nos. 7-372444, 7-854466, Japanese Patent Application Laid-Open No. 10-27332 and Japanese Patent Application Laid-Open As described in Japanese Patent Application Laid-Open No. 10-105594, a metal deposition layer is formed as a back coat layer on the surface of the non-magnetic substrate opposite to the surface on which the magnetic layer is formed. A magnetic recording medium in which rigidity is ensured by the back coat layer has been proposed.
  • the high-density magnetic recording medium (100) shown in Fig. 3 is formed on one surface of a non-magnetic substrate (11).
  • Magnetic layer (12), protective layer (13) formed on magnetic layer (12), lubricant layer (15) formed on protective layer (13), and non-magnetic substrate A magnetic tape having a back coat layer (14) formed on the other side of (11) and a lubricant layer (16) formed on the back coat layer (14).
  • the non-magnetic substrate (11) is made of a non-magnetic material such as polyethylene terephthalate, polyethylene naphthalate, and polyparatetraamide (hereinafter sometimes abbreviated to PET, PEN, and PPTA in this order).
  • the surface on the side in contact with the magnetic layer of the non-magnetic substrate made of these materials in general, fine particles consisting of S i 0 2 or Z eta theta such inorganic materials or ultrafine particles formed of an organic material such as imide, , Are dispersed and fixed.
  • the thickness of the non-magnetic substrate (11) is generally about 2-7 // m.
  • the magnetic layer (12) is a ferromagnetic metal thin film.
  • the magnetic layer (12) is made of, for example, a ferromagnetic metal such as Co, Ni or Fe, or an alloy containing these as a main component.
  • the magnetic layer (12) has a single-layer or multilayer structure.
  • the magnetic layer (12) is formed by, for example, an oblique evaporation method in which the incident angle of the metal vapor is continuously changed. When the oblique deposition is performed in an oxygen atmosphere, the magnetic layer contains oxygen. Or the magnetic layer
  • the (12) is a perpendicular magnetization film.
  • a perpendicular magnetization film For example, a perpendicular magnetization film. It is formed by obliquely depositing o-Cr or Co in an oxygen atmosphere as necessary.
  • the thickness of the magnetic layer (12) is generally 30 to 30 O nm.
  • the protective layer (13) is formed in order to prevent the magnetic layer (12) from being damaged (damage) by an externally applied force or the like.
  • the material forming the protective layer (13) is a substance having high hardness such as diamond-like carbon.
  • the thickness of (13) is generally :! ⁇ 5 O nm.
  • the back coat layer ( 14) is formed by applying a metal thin film formed by evaporating an appropriate metal, for example, a metal oxide thin film formed by evaporating an appropriate metal in the presence of oxygen, for example, or a binder containing carbon particles.
  • a metal thin film formed by evaporating an appropriate metal for example, a metal oxide thin film formed by evaporating an appropriate metal in the presence of oxygen, for example, or a binder containing carbon particles. This is a carbon film formed by the following method.
  • the lubricant layer (15) is formed to improve the running property of the magnetic recording medium.
  • the lubricant layer (15) is a layer formed by applying, for example, a fluorine-based lubricant or the like.
  • the thickness of the lubricant layer (15) is generally 0.05 to 50 nm.
  • the lubricant layer may also be formed on the surface of the back coat layer.
  • the lubricant layer (16) is provided to improve the running property of the magnetic recording medium.
  • the formation of a lubricant layer on the surface of a coating layer is described in, for example, Japanese Patent Application Laid-Open
  • a magnetic recording medium When a magnetic recording medium is used as a magnetic recording tape, it receives a large frictional force from a traveling system member such as a video deck, so that a notch coat layer made of a metal thin film has a lubricant layer on its surface. Even if formed, it is still prone to wear. Therefore, it is desired to further improve the lubricant layer provided on the surface of the back coat layer to further improve the durability, running properties, corrosion resistance, and the like of the magnetic recording medium.
  • the present invention has been made in view of such circumstances, and relates to a case where a high-density magnetic recording medium having a magnetic layer on one surface of a nonmagnetic substrate and a backcoat layer on the other surface is used as a magnetic recording tape. Another object is to improve the running durability of the magnetic recording medium and further improve the practical reliability. The present invention has been made to solve this problem. Disclosure of the invention
  • the present invention provides a nonmagnetic substrate, a magnetic layer formed on one surface of a nonmagnetic substrate, a metal thin film formed as a back coat layer on the other surface of the nonmagnetic substrate, and A magnetic recording medium having a lubricant layer formed on a back coat layer, wherein the lubricant layer comprises at least one compound selected from the compounds represented by the general formula (a);
  • a magnetic recording medium comprising a lubricant containing a compound represented by b) and at least one compound selected from compounds represented by general formula (c):
  • R 1 represents an aliphatic alkyl group or an aliphatic alkenyl group
  • R 2 represents Represents a fluoroalkyl group, a fluoroether group or a fluoropolyether group, wherein a is 0 or 1, and b is an integer of 0 to 20.
  • R 3 represents a fluoroalkyl group, a fluoroether group, or a fluoropolyether group
  • R 4 represents an aliphatic alkyl group or an aliphatic alkenyl group
  • c is an integer of 0 to 20).
  • X is _OH, one COOH, —COOR 5 , or one OCOR 5 , wherein R 5 represents an aliphatic alkyl group or an aliphatic alkenyl group, and i and j are
  • the rigidity of the magnetic recording medium of the present invention is ensured by the back coat layer which is a metal thin film. Further, by specifying the type of the compound constituting the lubricant layer formed on the back coat layer as described above, the magnetic recording medium caused by friction with a traveling system member such as a video deck and a cassette deck can be obtained. Abrasion of the backcoat layer is reduced or prevented. Therefore, the magnetic recording medium of the present invention exhibits excellent running properties and durability even under severe environments.
  • a protective layer is formed on the back coat layer, and a lubricant layer is formed on the protective layer.
  • the protective layer formed on the back coat layer preferably comprises a diamond-like layer. Since the diamond-like force has an appropriate hardness, damage to the magnetic recording medium is effectively suppressed without damaging the traveling system members.
  • the protective layer composed of diamond-like carbon formed on the back coat layer preferably has a nitrogen-containing plasma polymerized film at the surface.
  • the presence of the nitrogen-containing plasma polymerized film improves the chemical adsorption of the lubricant in the lubricant layer to the protective layer.
  • a protective layer is formed on the magnetic layer, a lubricant layer is formed on the protective layer, and the lubricant layer is formed of the general formula
  • a lubricant layer containing a lubricant containing a specific compound is formed above both the back coat layer and the magnetic layer, and the specific compound is present on the exposed surface of the magnetic recording medium.
  • a magnetic recording medium having such an exposed surface shows better running properties.
  • the metal constituting the back coat layer is a non-magnetic metal.
  • Non-magnetic metals are preferably used because they do not adversely affect the magnetism of the magnetic layer.
  • the back coat layer is formed by evaporating a metal. Films formed by metal deposition have high strength and high rigidity even when thin. More preferably, the back coat layer is formed by evaporating a metal in an oxygen atmosphere. Such a backcoat layer is more rigid.
  • the magnetic layer is a thin ferromagnetic metal film. That is, the present invention is preferably applied to a high-density recording medium.
  • the ferromagnetic metal thin film is preferably formed by obliquely depositing a ferromagnetic metal on a non-magnetic substrate supported on a can-shaped rotating body or a belt-shaped support.
  • the magnetic layer thus formed exhibits excellent magnetic properties and is suitable for high-density recording.
  • preferred embodiments of the magnetic recording medium of the present invention include those obtained by combining two or more of the features of the preferred embodiments of the magnetic recording medium of the present invention. Such a magnetic recording medium has more excellent performance because it has the characteristics of each aspect.
  • the present invention also provides a method for manufacturing the magnetic recording medium of the present invention.
  • the step of forming a lubricant layer on the back coat layer is performed by dissolving the lubricant in a mixed organic solvent of a hydrocarbon solvent and an alcohol solvent.
  • the method includes applying a coating solution on the back coat layer. Protective layer on back coat layer If formed, the coating solution is applied over the protective layer.
  • This manufacturing method is characterized in that a lubricant layer is formed on a protective layer formed on a back coat layer or a back coat layer. According to this manufacturing method, a thin lubricant layer is uniformly formed on the back coat layer or on the protective layer formed on the back coat layer.
  • the method for manufacturing a magnetic recording medium of the present invention preferably includes forming a back coat layer by an evaporation method. If the back coat layer is formed by an evaporation method, a thin film having high strength and high rigidity can be used as the back coat layer.
  • the back coat layer is more preferably formed by depositing a metal under an oxygen atmosphere. This is because the backcoat layer has a higher level of removability.
  • FIG. 1 is a schematic sectional view of the magnetic recording medium of the present invention.
  • FIG. 2 is a schematic sectional view of the magnetic recording medium of the present invention.
  • FIG. 3 is a schematic sectional view of a conventional magnetic recording medium.
  • the “surface” of each layer or film constituting the magnetic recording medium is a surface that is exposed when each layer or film is formed, that is, The surface of each layer or film farther from the nonmagnetic substrate is meant.
  • the expression “above” each layer or film means “at a position away from the nonmagnetic substrate in a direction away from the nonmagnetic substrate”.
  • the “magnetic layer side surface” of the magnetic recording medium is an exposed surface of the magnetic recording medium, and refers to an exposed surface of a layer or a film formed on or above the magnetic layer. Therefore, for example, when the protective layer is formed on the magnetic layer and the lubricant layer is formed on the protective layer, the exposed surface of the lubricant layer corresponds to the “magnetic layer side surface”.
  • the “backcoat layer side surface” of the magnetic recording medium is an exposed surface of the magnetic recording medium, and refers to an exposed surface of a layer or a film formed on or above the backcoat layer. In the magnetic recording medium of the present invention, since the lubricant layer is formed on the back coat layer or on the protective layer formed on the back coat layer, the exposed surface of the lubricant layer is formed on the back coat layer side. Surface ".
  • the surface of the non-magnetic substrate on which the magnetic layer is formed may be referred to as “front surface”, and the surface of the non-magnetic substrate on which the back coat layer is formed may be referred to as “back surface”.
  • front surface the surface of the non-magnetic substrate on which the back coat layer is formed
  • back surface the surface of the non-magnetic substrate on which the back coat layer is formed
  • front surface of the non-magnetic substrate is used as a reference surface
  • a layer formed on or above the non-magnetic substrate may be referred to as a layer on the front surface side.
  • a layer formed above or above may be referred to as a layer on the back side.
  • FIG. 1 and FIG. 2 each schematically show a cross section of an example of the magnetic recording medium of the present invention.
  • the magnetic recording medium (10) shown in FIG. 1 includes a magnetic layer (2) formed on one surface (that is, the front surface) of the non-magnetic substrate (1) and a magnetic layer ( 2) a protective layer (3) formed on the protective layer (3), a lubricant layer (6b) formed on the protective layer (3), and a non-magnetic substrate (1) formed on the other surface (ie, the back surface).
  • the magnetic recording medium (20) shown in FIG. 2 further includes a protective layer (7) formed on the back coat layer (4), and the lubricant layer (6a) is formed on the protective layer (7). It is formed.
  • the former in order to distinguish a lubricant layer formed on a back coat layer from a lubricant layer formed on a magnetic layer, the former is referred to as a “rear side lubricant layer” and May be referred to as “front lubricant layer”.
  • the protective layer when a protective layer is formed on the back coat layer, the protective layer is called a “backside protective layer”, and the protective layer formed on the magnetic layer is called a “backside protective layer”.
  • Front side protective layer ".
  • the front-side lubricant layer and the front-side protective layer are formed on the surface of the non-magnetic substrate on which the magnetic layer is to be formed, so that the “magnetic layer-side lubricant layer” and the “magnetic layer-side protective layer” are respectively provided. It can also be called. Since the back side lubricant layer and the back side protection layer are formed above the surface of the non-magnetic substrate on which the back coat layer is formed, the “back coat layer side lubricant layer” and “back side lubricant layer” are respectively formed. It can also be called “coat layer side protective layer”.
  • the magnetic recording medium of the present invention is characterized in that the back side lubricant layer (6a) contains two or more specific fluorine-containing compounds. Therefore, the back side lubricant layer (6a) will be described first.
  • the back side lubricant layer (6a) is selected from at least one compound selected from the compounds represented by the general formula (a), and selected from the compounds represented by the general formulas (b) and (c). Includes a lubricant containing at least one compound.
  • the backside lubricant layer (6a) may contain, in addition to these specific compounds, other known lubricants, antioxidants, and Z or extreme pressure agents, if necessary.
  • R 1 is an alkyl group or an alkenyl group.
  • R 1 preferably has 6 to 30 carbon atoms, and more preferably 10 to 24 carbon atoms. If the number of carbon atoms is less than 6, or if the number of carbon atoms is 30, the lubrication performance of the compound may be reduced.
  • R 2 is a fluoroalkyl group, a fluoroether group or a polyether group.
  • R 2 is a fluoroalkyl group, it preferably has 1 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms.
  • the fluoroalkyl group is a perfluoroalkyl group.
  • R 2 is a fluoroether group or a fluoropolyether group
  • the molecular weight is preferably from about 200 to about 6000, more preferably from about 300 to about 4000. When the molecular weight is less than 200 or more than 6000, lubricity and reliability of the magnetic recording medium may be reduced. Further, the fluoroether group or the fluoropolyether group is preferably a perfluoroether group or a perfluoropolyether group.
  • a is 0 or 1.
  • b is an integer from 0 to 20, preferably an integer from 0 to 12.
  • R 2 is a fluoroether group or a fluoropolyether group
  • R 2 is preferably represented by any one of formulas (d), (e) and (f).
  • k is an integer of 1 or more, preferably an integer of 1 to 8.
  • p and q are integers of 1 or more. p and q are each preferably 1 to 30, and more preferably 1 to 8.
  • the portion corresponds to a portion where two kinds of oxyfluoroalkylene units are copolymerized, and p and q indicate the number of each oxyfluoroalkylene unit in the copolymer.
  • a copolymer consisting of oxyfluoroalkylene units (OCF (CF 3 ) CF 2 ) and oxyfluoroalkylene units (OCF 2 ) is composed of p (OCF (CF 3 ) CF 2 ) blocks.
  • the group represented by the general formula (e) is a group represented by one (OCF (CF 3 ) CF 2 ) p (OCF 2 ) q — in which a block copolymer, a random copolymer and an alternating copolymer are used. Including those that are united.
  • R 6 represents a fluoroalkyl group
  • m is an integer of 1 to 6
  • n is an integer of 1 to 30.
  • R 6 is preferably a perfluoroalkyl group.
  • the carbon number of R 6 is preferably 1 to 30, more preferably 1 to 8.
  • n is more preferably an integer of 1 to 8.
  • the compound represented by the general formula (a) is an alkyl succinic anhydride or an alkenyl succinic anhydride, and an alcohol represented by the general formula R 2 (CH 2 ) b OH (wherein R 2 and b are R 2 and b in the formula (a)) are mixed and heated and stirred in an appropriate solvent. Heating is preferably performed within the range of 60 to 100 ° C. A more preferred heating temperature range is 80 to 90 ° C. If the heat temperature is less than 60 ° C, unreacted substances tend to remain. If the temperature exceeds 100 ° C, by-products tend to be generated.
  • the reaction between succinic anhydride and alcohol proceeds advantageously by heating and stirring in the presence of a solvent.
  • the solvent is, for example, octane (n—C 8 H 18 ) or heptane (n_C 7 H 16 ).
  • the mixing molar ratio of succinic anhydride and alcohol is 1: 1 Is preferred.
  • the solvent is removed by distillation under reduced pressure, and the unreacted reactants are extracted and removed with an organic solvent, whereby the fluorinated carboxylic acid as the target compound can be isolated.
  • This compound can be identified by infrared spectroscopy (IR), gel permeation chromatography (GPC) and organic mass spectrometry (FD-MS).
  • the compound represented by the formula (1) has one fluorine-containing terminal group, i.e., a fluoroalkyl terminal group, a fluoroetherene terminal group or a fluoropolyether terminal group, and one aliphatic hydrocarbon terminal group in the same molecule. That is, it is a fluorine-containing monoester having a structure having an aliphatic alkyl terminal group or an aliphatic alkenyl terminal group and one ester bond.
  • R 3 is a fluoroalkyl group, a fluoroether group, or a fluoropolyether group.
  • R 3 is a fluoroalkyl group, it preferably has 1 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms.
  • the fluoroalkyl group may be straight-chain or branched. It is preferable that the fluoro group alkyl group is a perfluoro alkyl group.
  • the fluoroalkyl group is preferably a perfluorohexyl group, a perfluoroheptyl group, a perfluorooctyl group, a perfluorononyl group, or a perfluorodecyl group.
  • R 3 is a fluorine-containing ether group or a fluorine-containing polyether group
  • the molecular weight is preferably from about 200 to about 600, and preferably from about 300 to about 400. More preferably. When the molecular weight is less than 200 or more than 600, lubricity and reliability of the magnetic recording medium may be reduced.
  • Fluoroe The ter group or fluoropolyether group is preferably a perfluoroether group or a perfluoropolyether group.
  • R 3 is a fluorine-containing ether group or a fluorine-containing polyether group
  • R 3 is any one of the above general formulas (d), (e) and (f), similarly to R 2 in the above general formula (a). Is preferable.
  • c corresponds to the number of methylene (one CH 2 _). c is preferably an integer of 0 to 20, more preferably an integer of 0 to 12. Even if the compound represented by the general formula (b) does not have a methylene chain, the performance of the lubricant containing this compound is not adversely affected. Thus, c contains 0.
  • R 4 is an aliphatic alkyl group or an aliphatic alkyl group.
  • R 4 preferably has 6 to 30 carbon atoms, and more preferably 10 to 24 carbon atoms. If the number of carbon atoms is less than 6 or exceeds 30, the lubricating performance may decrease.
  • R 4 may be linear or branched or displaced.
  • R 4 is, specifically, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a henycosyl group, a docosyl group, a dodecenyl group, 1 —Tridecyl group, 1-Tetradecenyl group, 1-Pentadeceyl group, 1-Hexadecenyl group, 1-Heptadecenyl group, 1-Octadeceyl group, 1-Nonadecyl group, 1-Icocenyl group, 11-Henikosiel It is preferably any one of a group and a 1-docosenyl group.
  • the compound represented by the general formula (b) can be synthesized by reacting a fluorinated alcohol with a fatty acid. This reaction can be conveniently proceeded by mixing and stirring the fluorinated alcohol and the fatty acid in a solvent while heating in the presence of a catalyst.
  • a catalyst Preferably, heptane, octane or toluene is used as the solvent.
  • the heating temperature is preferably from 80 to 150 ° C, more preferably from 120 to 130 ° C.
  • the catalyst is preferably an acid catalyst, and for example, p-toluenesulfonic acid can be used.
  • the molecular weight of the fluoropolyether compound is preferably about 1000 to about 20000, more preferably about 1000 to about 4000.
  • X in the general formula (c) is a hydroxyl group, a carboxyl group, an alkoxycarbonyl group (one COOR 5 ) or an acyloxyl group (one OCOR 5 ).
  • R 5 is an aliphatic alkyl group or an aliphatic alkenyl group.
  • R 5 preferably has 1 to 24 carbon atoms, and more preferably 12 to 20 carbon atoms.
  • R 5 is preferably a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecinole group or an icosyl group.
  • i and j are integers of 1 or more. Each of i and j is preferably an integer of 1 to 30, more preferably an integer of 1 to 8. h is an integer of 0 to 12, preferably 0 to 6.
  • the portion represented by 1 (OC 2 F 4 ) i (OCF 2 ) 1 corresponds to a portion where two kinds of oxyfluoroalkylene units are copolymerized, and i and j Represents the number of each oxyfluoroalkylene unit in the copolymer.
  • the copolymer consisting of oxyfluoroanorylene units (OC 2 F 4 ) and oxyfluoroalkylene units (OCF 2 ) is composed of i (OC 2 F 4 ) blocks and j (OCF 2 ) blocks. And other block copolymers, random copolymers, or alternating copolymers.
  • the portion represented by (OC 2 F 4 ) ; (OCF 2 ) ”— is a block copolymer, a random copolymer and an alternating copolymer. Including things.
  • Fomblin Z Dol is a compound represented by the general formula (c), wherein X is a hydroxyl group, h is an integer of 1 to 11, i Is an integer of 1 to 15 and j corresponds to a compound represented by an integer of 1 to 15.
  • X is a carboxyl group
  • Fomblin Z Diac is represented by an integer of h force S 0 to 10; an integer of i force 1 to 15; and j is an integer of 1 to 15 It corresponds to a compound.
  • Fluoropolyether compounds having alkoxycarboxy groups at both ends of the molecule are perfluoroether compounds having carboxyl groups at both ends of the molecule (for example, the aforementioned Fomblin Z Diac (trade name)). ) And an alcohol represented by R 5 OH.
  • a fluoropolyether compound having an acyloxyl group at both ends of the molecule is a perfluoroether compound having a hydroxyl group at both ends of the molecule (for example, the aforementioned Fomblin Z Dol (trade name)) and R 5 COOH Can be produced by subjecting a carboxylic acid represented by the formula to an esterification reaction.
  • the compound represented by the general formula (c) is obtained by directly fluorinating a hydrocarbon polyether having a predetermined skeleton by a fluorination method in the presence of a hydrogen fluoride scavenger, so that both terminals are acid fluoride (_COF).
  • a modified fluoropolyether compound is obtained, subjected to a predetermined reaction, and bonded to both ends of the molecule with a predetermined group to produce the compound.
  • the skeleton of the hydrocarbon polyether is selected based on h, i, and j in general formula (c).
  • Hydrolysis of a fluorinated polyether compound having an acid fluoride at the end gives a product having carboxyl groups bonded to both ends.
  • this fluoropolyether compound having a carboxyl group is reduced, the carboxyl group becomes _CH 2 OH, and a fluoropolyether compound having a hydroxyl group is obtained.
  • a fluoropolyether compound having a carboxyl group is reacted with an alcohol, a compound having an alkoxycarbonyl group bonded to both terminals can be obtained.
  • a fluoropolyether compound having a hydroxyl group is reacted with a carboxylic acid, a compound having an acyloxyl group bonded to both terminals can be obtained.
  • the lubricant contained in the back side lubricant layer (6a) of the magnetic recording medium of the present invention comprises a compound selected from the compounds represented by the general formula (a), a compound represented by the general formula (b) and a compound represented by the general formula (b) And (c) a compound selected from the group consisting of:
  • the lubricant contained in the back side lubricant layer (6a) is composed of a compound represented by the general formula (a), a compound represented by the general formula (b) and a compound represented by Z or the general formula (c). Is preferably contained in a ratio of 2: 8 to 8: 2 by weight, more preferably in a ratio of 4: 6 to 7: 3.
  • the lubricant contains both the compound represented by the general formula (b) and the compound represented by the general formula (c) (that is, in the lubricant of the above (3))
  • the ratio of the former to the latter is expressed by weight.
  • Each compound is contained in the back side lubricant layer (6a) preferably in a mixed state.
  • the back side lubricant layer (6a) contains, in addition to the compounds represented by the general formulas (a) to (c), other lubricants, antioxidants and Z or extreme pressure agents. May include.
  • the combined amount of the compound represented by the general formula (a) and the compound represented by the general formula (b) and the compound represented by ⁇ or the general formula (c) is determined by the amount of the compound represented by the general formula (c) and other lubricants.
  • the thickness of the back side lubricant layer (6a) is preferably from 0.05 to 50 nm, more preferably from 1 to 10 nm. If the thickness of the back side lubricant layer (6a) is less than 0.05 nm, the friction coefficient of the surface of the back coat layer side becomes large, and the running property of the entire tape may be deteriorated. As a result, the front protective layer (3) may be damaged. If the thickness of the back side lubricant layer (6a) exceeds 5 O nm, running failure occurs, which is not preferable.
  • the step of forming the back side lubricant layer (6a) is performed by dissolving the lubricant in a mixed organic solvent of a hydrocarbon solvent and an alcohol solvent and applying a coating solution prepared on the back coat layer (as described below).
  • the method includes coating on the back side protective layer) and drying the applied coating solution to evaporate the mixed organic solvent.
  • the mixed organic solvent evaporates, so that the lubricant dissolved in the solvent remains on the surface of the back coat layer (or the surface of the backside protective layer) to form a lubricant layer.
  • the coating thickness of the coating liquid is increased, a uniform and very thin lubricant layer is formed on the back coat layer by evaporation of the solvent.
  • the lubricant layer is formed in this manner, the surface of the coating layer can be uniformly coated with a small amount of lubricant.
  • hydrocarbon solvent examples include toluene, hexane, heptane, octane, nonane, xylene, and ketone.
  • examples of the anolecoholic solvent that can be used in the present invention include methyl alcohol and ethyl alcohol. Normal alcohols are lower alcohols such as pill alcohol, isopropyl alcohol and butyl alcohol.
  • the mixed organic solvent is preferably a mixed solvent of toluene and isopropyl alcohol or a mixed solvent of hexane and isopropyl alcohol.
  • the mixing ratio of the alcohol solvent and the hydrocarbon solvent is preferably in the range of 1: 9 to 9: 1 by weight, more preferably in the range of 3: 7 to 7: 3. If the proportion of the alcohol-based solvent is too large, coating unevenness tends to occur. It is uneconomical if the proportion of the hydrocarbon solvent is too large.
  • the back coat layer In the case of forming the backside protective layer, the backside protective layer
  • a lubricant layer of uniform thickness without coating glare that uniformly covers the surface is formed. As a result, a magnetic recording medium having excellent lubricity and high practical reliability can be obtained.
  • the concentration and the coating thickness of the coating solution are selected so that the backside lubricant layer formed on the backcoat layer after the solvent evaporates has a desired thickness.
  • Methods for forming a lubricant layer using the above-mentioned coating solution include wet coating methods such as bar coating, gravure coating, reverse coating, die coating, dipping and spin coating, and organic vapor deposition. There is. In the present invention, any method may be adopted.
  • a drying treatment is performed to evaporate the organic solvent, whereby a lubricant layer is formed on the protective film.
  • the drying treatment can be performed by heating or natural drying.
  • the backside lubricant layer (6a) is formed on the protective layer (that is, the backside protective layer) (7) formed on the backcoat layer (4). Good.
  • the rear protective layer (7) further improves the storability and running performance of the magnetic recording medium.
  • the backside protective layer (7) can be formed on the backcoat layer (4) by conventional materials and methods used to form the frontside protective layer (3) on the magnetic layer (2). it can.
  • the backside protective layer (7) is made of, for example, an amorphous, graphite or diamond-like carbon film obtained by a method such as sputtering or plasma CVD, or a mixture of such carbon and Z or Is a carbon film formed by lamination.
  • the backside protective layer (7) is preferably formed of diamond-like carbon, that is, diamond-like carbon.
  • Diamond-like carbon is the most preferred material because it has an appropriate hardness and suppresses damage to the magnetic recording medium without damaging the running members in contact with the back coat layer side surface.
  • the thickness of the backside protective layer (7) is preferably from!
  • the backside protective layer (7) is a carbon film
  • its surface layer is preferably a nitrogen-containing plasma polymerized film.
  • the backside protective layer is a nitrogen-containing plasma polymerized film
  • the “surface layer portion of the protective layer” means a layer including a surface of the rear protective layer that is in contact with the rear lubricant layer.
  • a nitrogen-containing plasma polymerized film For a nitrogen-containing plasma polymerized film, an object to be treated including a carbon film formed by plasma CVD or the like is placed in a vacuum vessel, and propylamine, butylamine, ethylenediamine, propylenediamine, or tetramethylenediamine is placed in the vacuum vessel.
  • An amine compound such as mine is gasified and introduced, and the surface of the carbon film is exposed to the amide compound gas, and high-frequency discharge is performed inside the vacuum vessel while maintaining the pressure in the vessel at 0.1 to 100 Pa. It is formed by causing Methods for forming a nitrogen-containing plasma polymerized film on the surface layer of a carbon film (protective layer) are disclosed in U.S. Patent Nos. 5,540,957 and 5,637,933. The contents disclosed in these patents by reference form part of the present specification.
  • the thickness of the nitrogen-containing plasma polymerized film is preferably 0.3 to 3 nm.
  • the thickness is less than 0.3 nm, the chemical adsorption between the lubricant component and the protective layer cannot be sufficiently improved.
  • the thickness is 3 nm or more, the protective effect of the protective layer itself is reduced.
  • the rear protective layer (7) may be a film formed by a wet coating method.
  • the backside protective layer (7) is formed by dissolving and / or dispersing carbon particles, barium ferrite, and polyurethane resin in an appropriate solvent (for example, a mixed solvent of toluene and methyl ethyl ketone). Is prepared, and the coating solution is applied on the batter coat layer, and then dried to evaporate the solvent.
  • carbon particles impart strength to the back coat layer
  • barium ferrite regulates the Young's modulus of the back coat layer
  • polyurethane resin forms carbon particles and barium ferrite. It acts as a binding binder.
  • one or more types of particles selected from metal particles, metal oxide particles and metal nitride particles may be used.
  • a polyester resin may be used instead of the polyurethane resin or together with the polyurethane resin.
  • barium Blow barium sulfate and z or calcium carbonate may be used, or together with barium ferrite.
  • the thickness of the backside protective layer formed by the wet coating method is preferably 200 to 60 Onm (0.2 to 0.6 / m).
  • the backside lubricant layer (6a) formed on the backside protective layer (7) is also formed according to the method described above.
  • the coating solution prepared by dissolving the lubricant in the mixed organic solvent is applied to the surface of the backside protective layer (7), that is, the surface opposite to the surface in contact with the backcoat layer (4).
  • the nonmagnetic substrate (1), the magnetic layer (2), the front protective layer (3), the back coat layer (4), and the front lubricant layer (6b ) Is explained.
  • the non-magnetic substrate (1) is a film made of a polymer.
  • the non-magnetic substrate (1) may be formed using conventional materials and methods. Since the back coat layer (4) secures the rigidity required for the magnetic recording medium, the thickness of the non-magnetic substrate (1) can be small. Specifically, the thickness of the non-magnetic substrate (1) is preferably 2 to 7 ⁇ . If the thickness of the nonmagnetic substrate (1) is less than 2 / m, it is difficult to form a magnetic layer on the surface. If the thickness of the non-magnetic substrate (1) exceeds 7 / xm, the proportion of the non-magnetic substrate in the entire magnetic recording medium increases, which is disadvantageous for a high-density magnetic recording medium.
  • the material and structure of the non-magnetic substrate (1) are not particularly limited.
  • the material of the non-magnetic substrate can be selected from the group consisting of PET, PEN, PPTA and the like.
  • the heat load on the non-magnetic substrate increases due to heating during the vapor deposition. Therefore, when a non-magnetic substrate having poor heat resistance is used, the substrate may be melted or discolored.
  • the winding tension during vapor deposition should be increased to enhance cooling. However, if the winding tension is increased when the magnetic layer (2) is formed on the non-magnetic substrate (1), cracks may occur in the magnetic layer (2). Cracks are more likely to occur as the thickness of the nonmagnetic substrate (1) is smaller.
  • a non-magnetic substrate (1) made of a heat-resistant material such as PEN and PPTA.
  • Ultra-fine particles are dispersed on the surface of the non-magnetic substrate (1) where the magnetic layer (2) is formed (that is, the surface in contact with the magnetic layer (2)) in order to improve the running properties of the magnetic recording medium. It is preferable that they are fixed.
  • the ultrafine particles are preferably ultrafine particles having a diameter of 5 to 5 Onm made of an inorganic substance such as SiO 2 or ZnO or an organic substance such as imide. Such ultrafine particles, 1 ⁇ 2 diary 3-150 pieces, it is desirable that the distributed fixed.
  • the ultrafine particles may be dispersed and fixed also on the surface of the non-magnetic substrate (1) where the back coat layer (4) is formed.
  • Examples of such a non-magnetic substrate are disclosed in Japanese Patent Application Laid-Open Nos. 9-164644 and 10-261215.
  • the magnetic layer (2) of the magnetic recording medium of the present invention is preferably a ferromagnetic metal thin film.
  • Suitable ferromagnetic metals for the magnetic layer include Fe-based metals, Co-based metals, and Ni-based metals.
  • Co-based metal refers to an alloy containing cono-court and cobalt as a main component, preferably at least 50 atomic%. The same applies to “Fe-based metal” and “Ni-based metal”.
  • the magnetic layer (2) is composed of Fe, Co, Ni, Co—Ni, Co—Fe, Co—Cr, Co_Cu, Co—Pt, and Co—Pd. , Co—Sn, Co—Au, Fe—Cr, Fe—Co—Ni, Fe—Cu, Ni—Cr, Fe—Co—Cr, Co_Ni—Cr, Co— It is formed of one or more materials selected from alloys such as Pt_Cr, Fe-Co_Ni-Cr, Mn-Bi, and Mn-A1.
  • the ferromagnetic metal film may include oxygen, which may be included in the form of oxides of these metals or alloys.
  • the ferromagnetic metal thin film may be in the form of a single-layer film, or may be in the form of a multilayer film.
  • the thickness of the magnetic layer is preferably 20 to 300 nm.
  • the magnetic layer (2) is formed by, for example, electron beam evaporation. Specifically, the magnetic layer (2) is formed by irradiating a ferromagnetic metal such as Co or Co_Ni alloy with an electron beam at a predetermined range of incident angle to evaporate the metal, which is then removed from a can-shaped rotating body or the like. It is formed by adhering to the surface of a non-magnetic substrate that moves along the cooling rotary support. If the deposition is performed in an oxygen atmosphere, a ferromagnetic metal thin film containing oxygen is formed. Magnetic layer (2) can be formed by other methods, for example, vapor deposition, ion plating, or sputtering performed by heating a metal by a resistance heating method or an externally heated crucible method.
  • a ferromagnetic metal such as Co or Co_Ni alloy
  • the magnetic layer (2) is preferably formed by an oblique evaporation method in which a ferromagnetic metal is obliquely vapor-deposited on the surface of the nonmagnetic substrate from the viewpoint of the formation (or film formation) speed of the magnetic layer.
  • the cooling rotary support of the non-magnetic substrate may be a can-shaped rotary body or a belt-shaped support. From the viewpoint of production efficiency, it is preferable to use a belt-shaped support having a wide evaporation area.
  • the front protective layer (3) is formed by conventional materials and methods.
  • the front side protective layer (3) is preferably a carbon film, particularly preferably a film made of diamond-like carbon.
  • the carbon film preferable as the front side protective layer (3) is the back side protective layer
  • the front protective layer (3) is 1 to 5 Onm.
  • the surface layer is preferably a nitrogen-containing plasma polymerized film.
  • the nitrogen-containing plasma polymer film formed on the surface layer of the front protective layer (3) is as described in relation to the backside protective layer (7). Therefore, the detailed description is omitted here.
  • the back coat layer ( 4) is a metal thin film.
  • the back coat layer ( 4 ) is preferably made of a non-magnetic metal so as not to adversely affect the magnetism of the magnetic layer.
  • the back coat layer (4) is, for example, selected from the group consisting of Ti, Cr, Mn, Fe, Al, Cu, Zn, Sn, Ni, Ag, Pb and Co, and alloys thereof. Formed using one or more selected metals. Since Fe, Ni and Co are magnetic substances, when they are used, they are preferably present in the back coat layer in a state of being oxidized to a non-magnetic substance.
  • the back coat layer (4) may be in the form of a single-layer film or in the form of a multilayer film.
  • the thickness of the back coat layer is preferably 10 to 60 Onm.
  • the backcoat layer (4) can be Cu, A1 or Zn, or Alternatively, it is preferable to use a Cu-based alloy, an A1-based alloy, or a Zn-based alloy containing Cu, A1 or Zn as a main component and preferably containing at least 50 atomic%.
  • A1 alloys and other alloys are commonly used as additives to improve corrosion resistance and mechanical strength, such as Cu, Mn, Fe, Si, Mg or Zn You can arbitrarily add things.
  • the back coat layer ( 4) is formed on the surface of the non-magnetic substrate opposite to the surface on which the magnetic layer (2) is formed.
  • the back coat layer (4) is preferably formed by vapor deposition.
  • the back coat layer (4) may be formed by sputtering, ion plating or plasma CVD.
  • the back coat layer (4) is formed in an oxygen atmosphere, and that the back coat layer (4) contains a metal oxide.
  • the back coat layer (4) containing metal oxide shows excellent corrosion resistance.
  • the knock coat layer (4) may contain oxygen that is not bonded to a metal in addition to the metal oxide. It is preferable that the oxygen concentration of the backcoat layer ( 4 ) increases as it approaches the surface. If the surface of the back coat layer (4) contains more oxygen, the corrosion resistance of the back coat layer is further improved.
  • the back coat layer (4) may be formed after the formation of the magnetic layer (2) on the non-magnetic substrate (1).
  • the metal forming the back coat layer (4) has a low melting point in order to reduce radiant heat and reduce the thermal load on the non-magnetic substrate (1) on which the magnetic layer (2) is formed.
  • the front lubricant layer (6b) may be formed of a lubricant widely used as a lubricant for magnetic recording media.
  • the front lubricant layer (6b) is also composed of at least one compound selected from the compounds represented by the general formula (a), the compound represented by the general formula (b) and the compound represented by the general formula (c) )) and at least one compound selected from the compounds represented by the formula (1).
  • a preferable mixing ratio of the compound represented by the general formula (a), the compound represented by the general formula (b) and the compound represented by Z or the general formula (c), and the general formula occupying the lubricant layer The preferred proportions of the compounds shown in (a) to (c) are related to the backside lubricant layer (6a). As described above. Therefore, a detailed description of the front side lubricant layer (6b) will be omitted.
  • the thickness of the front-side lubricant layer (6b) is preferably 0.05 to 50 nm, similar to that of the rear-side lubricant layer (6a).
  • the front lubricant layer (6b) can be formed in the same manner as the rear lubricant layer (6a).
  • the coating solution is applied on the front protective layer (3).
  • the composition of the lubricant constituting the front lubricant layer (6b) and the lubricant constituting the rear lubricant layer (6a) may be the same or different. Further, the thicknesses of both lubricant layers may be the same or different.
  • the magnetic recording medium is a magnetic tape and the exposed surface of the lubricant layer is the magnetic layer side surface
  • the front side lubricant layer and the batter coat layer May come into contact with each other, and the lubricant of the front lubricant layer may be transferred to the surface of the back coat layer.
  • the lubricant contained in the front lubricant layer is a compound represented by the general formula (a), a compound represented by the general formula (b) and a compound represented by the general formula (b) or Z or the compound represented by the general formula (c).
  • the backside lubricant layer containing those compounds is formed on the back coat layer without going through an independent lubricant layer forming step (for example, the wet coating step described above).
  • a magnetic recording medium having a backside lubricant layer formed by such transfer is also included in the magnetic recording medium of the present invention.
  • the present invention relates to a magnetic recording medium having a magnetic layer formed on one surface of a nonmagnetic substrate, and a backcoat layer formed of a metal thin film formed on the other surface of the nonmagnetic substrate, A lubricant layer is formed on the backcoat layer.
  • the lubricant layer has at least one compound selected from a specific fluorinated carboxylic acid, a specific fluorinated monoester and a specific fluorinated lubricant. And at least one compound selected from the group consisting of boropolyether ibi compounds. Due to this feature, the magnetic recording medium of the present invention exhibits excellent durability and running properties even in a severe environment and is highly reliable.
  • a protective layer is formed on the back coat layer and a lubricant layer is formed on the protective layer, or a nitrogen-containing plasma polymerized film is formed on the surface layer of the protective layer to form the nitrogen-containing plasma polymerized film.
  • Superior durability by forming a lubricant layer on top And a magnetic recording medium having running properties. Therefore, when the magnetic recording medium of the present invention is used as, for example, a tape, it can withstand a large frictional force applied from a traveling system member of a reproducing / recording apparatus such as a video deck for + minutes, and can be used repeatedly. Suitable for. Example
  • a magnetic recording medium having the structure shown in FIG. 1 was manufactured.
  • a PET film having a thickness of 4.5 ⁇ , a width of 150 pixels, and a length of 2000 mm was used as the nonmagnetic substrate (1) of the magnetic recording medium.
  • S i 0 2 consists diameter 2 onm fine particles were dispersed 100 2 per 1 / zm, locking has occurred.
  • a magnetic layer (2) was formed by oblique deposition on the surface of the PET film on which the fine particles were present.
  • Magnetic layer (2) is the pressure in the vacuum chamber and 2 X 10_ 2 Pa, while the non-magnetic substrate (1) is traveling at 65 m / min along the belt-like support is cooled rotary support, It was formed by evaporating Co in the crucible using an electron gun (output 18 kW). The thickness of the magnetic layer (2) was set to 20 Onm.
  • a back coat layer (4) of about 30 Onm was formed by evaporation using A 1.
  • the back coat layer (4) has a pressure in the vacuum chamber of 2 ⁇ 10 to 12 Pa.
  • the non-magnetic substrate (1) is moved along the can-shaped cooling rotary support at 12 mZ for electron transfer. It was formed by evaporating A1 in the crucible with a gun (power 5.5 kW).
  • oxygen was supplied to the non-magnetic substrate (1) during the vapor deposition so that the back coat layer (4) contained oxygen.
  • a 10 nm-thick front protective layer (3) made of diamond-like carbon was formed on the magnetic layer (2).
  • the front protective layer (3) was formed by a plasma CVD method that ionizes methane.
  • a gas mixture of methane gas and argon gas at a ratio of 4: 1 (pressure ratio) is introduced into a vacuum container, and the total gas pressure is reduced to 10 Pa. Apply voltage to the electrodes in the discharge tube while maintaining It formed by doing.
  • a compound represented by the following chemical formula (a1) and a compound represented by the following chemical formula (b1) were mixed at a ratio of 1: 1 (weight ratio) to prepare a lubricant.
  • This lubricant was dissolved in a mixed organic solvent in which isopropyl alcohol and toluene were mixed at a weight ratio of 1: 1 so that the concentration became 2000 ppm to prepare a coating solution.
  • This coating solution was applied to the surface of the back coat layer (4) to a thickness of about 8 O / xm by a wet coating method using a reverse roll coater, and then dried.
  • a rear-side lubricant layer having a thickness of 5 nm to include lubricant lm 2 per 5 m g (6 a) is formed.
  • the front side lubricant layer (6b) having the same composition and thickness as the back side lubricant layer (6a) is formed on the front side by the same method as the method for forming the back side lubricant layer (6a). It was formed on the protective layer (3).
  • a compound represented by the above formula (a1), a compound represented by the above formula (b1), and a compound represented by the following formula (c1) are mixed in a ratio of 2: 2: 1 (weight ratio).
  • a lubricant was prepared. Using this lubricant, a magnetic recording medium having a back side lubricant layer (6a) and a front side lubricant layer (6b) was produced in the same manner as in Example 1.
  • Example 3 A lubricant was prepared by mixing the compound represented by the chemical formula (a1) and the compound represented by the chemical formula (c1) at a ratio of 1: 1 (weight ratio). Using this lubricant, a magnetic recording medium having a back side lubricant layer (6a) and a front side lubricant layer (6b) was produced in the same manner as in Example 1.
  • a magnetic recording medium having the structure shown in FIG. 2 was manufactured.
  • the backside protective layer (7) was formed on the backcoat layer (4) and the backside lubricant layer (6a) was formed on the backside protective layer (7).
  • a magnetic recording medium was manufactured in the same manner as in Example 1.
  • the back side protective layer (7) like the front side protective layer (3), introduces a gas mixture of methane gas and argon gas at a ratio of 4: 1 (pressure ratio) into the vacuum vessel, and the total gas pressure While maintaining the pressure at 10 Pa, a voltage was applied to the electrodes in the discharge tube.
  • a nitrogen-containing plasma polymerized film (not shown) was formed on the surface of the backside protective layer (7), and the backside lubricant layer (6a) was formed so as to be in contact with the nitrogen-containing plasma polymerized film.
  • a magnetic recording medium was manufactured in the same manner as in Example 4. After forming the backside protective layer (7), the nitrogen-containing plasma polymerized film is treated by introducing propylamine gas into a vacuum vessel and performing high-frequency plasma treatment to obtain a surface layer of the backside protective layer (7). Formed. The thickness of the nitrogen-containing plasma polymerized film was 2.5 nm.
  • a magnetic layer (2) and a back coat layer (4) were formed on a non-magnetic substrate (1), and a front protective layer (3) was formed on the magnetic layer (2). .
  • a backside protective layer (7) was formed on the backcoat layer ( 4 ).
  • the backside protective layer (7) was composed of 500 parts by weight of toluene and methylethylketone each as a solvent, 100 parts by weight of polyurethane as a binder, 20 parts by weight of carbon, and A coating solution prepared by mixing 60 parts by weight of barium ferrite was applied onto the back coat layer (4), and then dried and the solvent was evaporated.
  • the thickness of the rear protective layer (7) was set to 50 Onra.
  • the front and rear lubricant layers (6b, 6a) were formed in the same manner as in Example 1, and magnetic recording was performed.
  • a medium was prepared.
  • a magnetic layer (2) and a back coat layer (4) were formed on a non-magnetic substrate (1), and a front protective layer (3) was formed on the magnetic layer (2). .
  • a back coat layer (4) of about 10 Onm was formed by vapor deposition using Cu.
  • the front-side and back-side lubricant layers (6b, 6a) were formed to produce a magnetic recording medium.
  • a magnetic recording medium was manufactured in the same manner as in Example 1, except that the back side lubricant layer was not formed.
  • a commercially available perfluoropolyether lubricant Fomblin AM 2001 (trade name; manufactured by Ausimont) was used as a lubricant, and the front and rear lubricant layers (6b, 6a) were used with this lubricant. ) was formed in the same manner as in Example 1 except that a magnetic recording medium was formed.
  • Example 1 was repeated except that only the compound represented by the chemical formula (a1) was used as a lubricant, and the front and rear lubricant layers (6b, 6a) were formed with this lubricant. Similarly, a magnetic recording medium was manufactured.
  • Example 1 was the same as Example 1 except that only the compound represented by the chemical formula (bl) was used as a lubricant, and the front and rear lubricant layers (6b, 6a) were formed with this lubricant. Similarly, a magnetic recording medium was manufactured.
  • a magnetic recording medium was manufactured in the same manner as in Example 1, except that the front and rear side lubricant layers (6b, 6a) were formed.
  • a magnetic recording medium was manufactured in the same manner as in Example 1, except that only isopropyl alcohol was used as the organic solvent for dissolving the lubricant.
  • a magnetic recording medium was manufactured in the same manner as in Example 1, except that only toluene was used as the organic solvent for dissolving the lubricant.
  • the tape damage was evaluated on a five-point scale by observing the state of the sample visually and with a differential interference microscope.
  • the evaluation criteria are as follows.
  • the dynamic friction coefficient / k of the surface on the back coat layer side was measured.
  • Each sample was wrapped around a friction member (stainless steel (SUS420 J2, surface roughness 0.2 S), outer diameter 6 mm) at a wrap angle of 90 °, and the sample was wrapped for 18 ⁇ Z seconds under a tension of 2 N.
  • the film was wound at the same speed, wound at the same speed, and the tension was measured on the winding side.
  • the coefficient of dynamic friction was calculated from the ratio of the tension on the winding side to the tension on the unwinding side using Euler's formula.
  • Each sample was left in an environment of 40 ° C. and 80% RH for 30 days. After standing, the still life and head clogging were measured for each sample.
  • the still life was measured under an environment of 3 ° C and 5% RH using a commercial digital VTR (Matsushita Electric Industrial Co., Ltd., trade name: NV-DJ1) modified for still life measurement. Still life is expressed as the time (min) from the beginning until the output drops by 6 dB.
  • Head clogging was performed using a commercially available digital VTR (Matsushita Electric Industrial Co., Ltd., NV—DJ1) modified for RF (high frequency) output measurement, at 23 ° C and 60% RH. Playback was repeated for 133 passes for 00 passes and head clogging was measured from the RF output during playback. It was assumed that head clogging occurred when the RF output decreased by 6 dB or more during this repetitive reproduction, and the time during which such a decrease was measured was defined as head clogging.
  • Table 1 shows the evaluation results of each test.
  • the magnetic recording media of Examples 1 and 4 to 6 having a lubricant layer containing the compound represented by the general formula (a) and the compound represented by the general formula (b) on the surface of the back coat layer, and the surface of the back coat layer.
  • the magnetic recording medium of Example 2 having a lubricant layer containing a compound represented by the general formula ( a ), a compound represented by the general formula (b) and a compound represented by the general formula (c), and the surface of the back coat layer.
  • Example 3 having a lubricant layer containing the compound represented by the general formula (a) and the compound represented by the general formula (c), Comparative Example 1 in which the lubricant layer was not present on the back coat layer, Comparative Example 2 containing only the perfluoroether-based lubricant in the back side lubricant layer, Comparative Example 3 containing only the compound represented by the general formula (a) in the back side lubricant layer, and represented by the general formula (b) Only the fluoropolyether compound contained in the lubricant layer Compared with the magnetic recording medium of Comparative Example 4 and Comparative Example 5 in which only the compound represented by the general formula (c) is included in the backside lubricant layer, all of them show excellent durability, running properties, and weather resistance. Was. This indicates that a lubricant containing a specific compound greatly contributes to improving the performance of a magnetic recording medium.
  • the magnetic recording medium of Example 1 using a mixed organic solvent consisting of isopropyl alcohol and toluene as the organic solvent for dissolving the lubricant was the same as that of Comparative Examples 6 and 7 using only isopropyl alcohol or toluene. Compared to magnetic recording media, it exhibited superior durability, running properties, and weather resistance.
  • Example 4 As for the magnetic recording media of Examples 4 to 6 having a protective layer on the back coat layer, better results were obtained with respect to durability and running properties as compared with Example 1. Furthermore, in Example 5 in which a nitrogen-containing plasma polymerized film was formed on the surface layer of the backside protective layer and in Example 6 in which the backside protective layer was formed by a wet coating method, Example 4 in which no nitrogen-containing plasma polymerized film was present was used. Compared with, better results were obtained in terms of runnability and weather resistance.
  • Example 7 a thin film made of Cu was formed as a back coat layer.
  • Example 7 also exhibited excellent durability, running properties, and weather resistance, as in Examples 1 to 6.
  • the lubricant other than the lubricant used in Example 17 above for example, selected from the compounds represented by the following chemical formulas (a2) (a3) (a4) (a5) and (a6) And at least one compound represented by the following chemical formulas (b2), (b3), (b4) and (b5) and the following chemical formulas (c1) (c2) (c3) (c4 ) And (c5) a magnetic recording medium in which a backside and front side lubricant layer is formed by using a lubricant mixed with at least one compound selected from the compounds represented by (c5), and a chemical formula (a1) (a 6) at least one compound selected from the compounds represented by the formulas (bl) and (b5) and at least one compound selected from the compounds represented by the formulas (c1) and (c5)
  • the magnetic recording medium of the present invention described above is suitable for high-density recording. Therefore, the magnetic recording medium of the present invention is useful as, for example, a tape for digital video recording equipment and a tape for data storage of a computer.

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

Abstract

L'invention concerne un support (10) d'enregistrement magnétique constitué d'un substrat (1) non magnétique, d'une couche (2) magnétique, d'une couche (3) de protection, d'une couche (4) de revêtement arrière et de couches (6a, 6b) lubrifiantes. Ledit support est caractérisé en ce que la couche lubrifiante (6a) formée sur la couche de revêtement arrière comporte un lubrifiant contenant au moins un composé choisi parmi les acides carboxyliques fluorés et au moins un composé choisi parmi les monoesters fluorés et les polyéthers fluorés.
PCT/JP2001/001421 2000-03-01 2001-02-26 Support d'enregistrement magnetique et procede de production correspondant WO2001065549A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2000-55659 2000-03-01
JP2000055659 2000-03-01

Publications (1)

Publication Number Publication Date
WO2001065549A1 true WO2001065549A1 (fr) 2001-09-07

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WO (1) WO2001065549A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1116149A (ja) * 1997-06-25 1999-01-22 Kao Corp 磁気記録媒体
WO1999003954A1 (fr) * 1997-07-16 1999-01-28 Matsushita Electric Industrial Co., Ltd. Composition lubrifiante, support d'enregistrement magnétique et procédé de production d'un support d'enregistrement magnétique
WO1999016850A1 (fr) * 1997-09-29 1999-04-08 Tdk Corporation Composition lubrifiante et support d'enregistrement magnetique fabrique a partir de ladite composition

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1116149A (ja) * 1997-06-25 1999-01-22 Kao Corp 磁気記録媒体
WO1999003954A1 (fr) * 1997-07-16 1999-01-28 Matsushita Electric Industrial Co., Ltd. Composition lubrifiante, support d'enregistrement magnétique et procédé de production d'un support d'enregistrement magnétique
WO1999016850A1 (fr) * 1997-09-29 1999-04-08 Tdk Corporation Composition lubrifiante et support d'enregistrement magnetique fabrique a partir de ladite composition

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