WO2001001402A1 - Support d'enregistrement magnetique - Google Patents

Support d'enregistrement magnetique Download PDF

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Publication number
WO2001001402A1
WO2001001402A1 PCT/JP2000/004211 JP0004211W WO0101402A1 WO 2001001402 A1 WO2001001402 A1 WO 2001001402A1 JP 0004211 W JP0004211 W JP 0004211W WO 0101402 A1 WO0101402 A1 WO 0101402A1
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WIPO (PCT)
Prior art keywords
magnetic
lubricant
recording medium
parts
magnetic layer
Prior art date
Application number
PCT/JP2000/004211
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English (en)
Japanese (ja)
Inventor
Takuya Ikeda
Eiichi Hasimoto
Original Assignee
Teijin Limited
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Filing date
Publication date
Application filed by Teijin Limited filed Critical Teijin Limited
Priority to AU55699/00A priority Critical patent/AU5569900A/en
Publication of WO2001001402A1 publication Critical patent/WO2001001402A1/fr

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Classifications

    • 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
    • C10M105/08—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound containing oxygen
    • C10M105/22—Carboxylic acids or their salts
    • 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
    • C10M105/08—Lubricating compositions characterised by the base-material being a non-macromolecular organic compound containing oxygen
    • C10M105/32—Esters
    • C10M105/34—Esters of monocarboxylic acids
    • 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
    • C10M107/00—Lubricating compositions characterised by the base-material being a macromolecular compound
    • C10M107/20—Lubricating compositions characterised by the base-material being a macromolecular compound containing oxygen
    • C10M107/30—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M107/32—Condensation polymers of aldehydes or ketones; Polyesters; Polyethers
    • 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
    • G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
    • G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
    • G11B5/708—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by addition of non-magnetic particles to the layer
    • 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
    • G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
    • G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
    • G11B5/71—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the lubricant

Definitions

  • the present invention relates to a magnetic recording medium, and more particularly to a high-density magnetic recording medium suitable for a large-capacity floppy disk having a storage capacity of 100 MB or more and having particularly excellent electromagnetic conversion characteristics, slipperiness, and durability.
  • the magnetic powder has a small particle diameter, that is, a Co-containing r-Fe 2 having a large specific surface area.
  • Magnetic powders such as O 3, barium ferrite, iron, and alloys have been used.
  • these magnetic powders are extremely difficult to disperse, causing agglomerated particles, an insufficiently filled state, and an uneven coating surface, thereby impairing the electromagnetic conversion characteristics of the coating film (magnetic layer).
  • they have the disadvantage that they tend to cause a decrease in slipperiness and durability.
  • the magnetic layer has been reduced in thickness to 0.5 im or less to improve the recording density, and the running speed of the medium has been increasing to improve the transfer speed.
  • the requirements for surface smoothness, running stability, and durability have become increasingly strict so that small, low-capacity drive motors can run stably for long periods of time. .
  • Non-magnetic intermediate between the support and the magnetic layer with good slippage for such technical problems Attempts to reduce or eliminate the influence of the surface roughness of the support by providing a layer are known.
  • Japanese Patent Application Laid-Open No. 49-73505 discloses that a polymer non-magnetic layer is formed between a non-magnetic substrate and a magnetic layer to prevent the effects of scratches and projections on the support in high-density recording. It is disclosed to avoid this.
  • the electromagnetic conversion characteristics were improved by such attempts, as the magnetic layer became thinner, not only the surface properties but also the requirements for running durability and the like became more severe. Not enough anymore.
  • Sho 62-154254 discloses a magnetic layer having a thickness of 0.5 m or less and a non-magnetic layer containing a conductive powder and a functional powder such as a lubricant formed to have a greater thickness.
  • the use of a magnetic intermediate layer is disclosed.
  • Japanese Patent Application Laid-Open No. 59-24437 discloses that at least one of a magnetic layer and a nonmagnetic layer contains an ester of oxy fatty acid as a lubricant.
  • the lubricant include silicon oil, fluorine oil, long-chain fatty acid, and long-chain fatty acid amide.
  • 62-188017 discloses that the surface roughness and Young's modulus of the nonmagnetic intermediate layer are regulated by selecting an inorganic powder.
  • the steps of applying, drying and smoothing the non-magnetic intermediate layer are performed independently of the step of forming the magnetic layer, the surface roughness is improved, but the intermediate step is not required in the step of applying the magnetic layer.
  • There were practical problems such as the layer being easily scratched, the rate of change in thickness being high, and insufficient running durability.
  • the lower non-magnetic intermediate layer is in a wet state by using a simultaneous multilayer coating method as disclosed in Japanese Patent Application Laid-Open No. Sho 63-91 1315.
  • a method of applying an upper magnetic layer in between has been proposed.
  • the productivity has reached a practical level by this method, it is difficult to suppress the disturbance of the interface between the nonmagnetic intermediate layer and the magnetic layer during drying, and it is more than 50% of the target thickness. There is a problem that the thickness may fluctuate.
  • Lubricant such as 2-hexyldecyl stearate, 2-hexyl decyl stearate, 2-octyldodecyl stearate, and 2-hexyl decyl stearate compare in durability under high temperature atmosphere. Although the target was good, there was a problem in running stability at low temperatures. There were also problems such as causing the so-called bleed phenomenon.
  • the present invention has been made in view of such circumstances, and has as its object a single-layer structure in which the above-described high-density recording can be performed only with a magnetic layer having a thickness of 0.5 / m or less and the conventional nonmagnetic intermediate layer can be omitted.
  • An object of the present invention is to provide a magnetic recording medium for high recording density.
  • the present invention has the following configuration to achieve the above object. That is, the present invention relates to a magnetic recording medium having a magnetic layer formed by applying a magnetic coating solution containing ferromagnetic powder on a nonmagnetic substrate, wherein the nonmagnetic substrate has a surface roughness on the surface on which the magnetic layer is formed. Has a center line average roughness Ra of 1 to 6 nm, the ferromagnetic powder is a ferromagnetic powder having a specific surface area of 30 m 2 / g or more according to the BET method, and the magnetic layer has a thickness of 0 m / g.
  • conductive non-magnetic powder having an average particle diameter of 0.1 m or less carrying lubricant 1 comprising at least a higher fatty acid or a fatty acid derivative, and having a fluorine surface. It is characterized by being coated and impregnated with a lubricant 2 composed of a system organic lubricant, and the total of the lubricant 1 and the lubricant 2 is 100 to 25 parts with respect to 100 parts of the ferromagnetic powder.
  • Magnetic recording medium is characterized by being coated and impregnated with a lubricant 2 composed of a system organic lubricant, and the total of the lubricant 1 and the lubricant 2 is 100 to 25 parts with respect to 100 parts of the ferromagnetic powder.
  • the present invention aims to improve the electromagnetic conversion characteristics by forming a magnetic layer containing a ferromagnetic powder having a specific surface area of 30 m 2 or more by a BET method on a nonmagnetic substrate having excellent surface smoothness.
  • the magnetic layer contains a conductive non-magnetic powder having a specific specific surface area suitable for supporting the lubricant, so that as much lubricant as possible can coexist in the magnetic layer.
  • the amount of conductive non-magnetic powder added was b for 100 parts of ferromagnetic powder, the oil absorption was a (ml / 100g), lubricant 1 and lubricant 1
  • (a X b ⁇ c) is particularly preferably in the range of 150 to 300 from the viewpoint of durability.
  • carbon black is preferred for this conductive non-magnetic powder because of its required conductivity and the ability to carry a lubricant in a relatively small amount.
  • the lubricant 1 comprises at least one ester compound (A) comprising a fatty acid having 3 or more branches and 9 to 18 carbon atoms and an alcohol having 3 or more branches and 8 to 17 carbon atoms.
  • ester compound (A) comprising a fatty acid having 3 or more branches and 9 to 18 carbon atoms and an alcohol having 3 or more branches and 8 to 17 carbon atoms.
  • it contains a species.
  • the ester compound (A) has the following general formula (1)
  • n, m, s, and t are integers, and the sum of n and m and the sum of s and t are each 2 to 8, and R "I and R 2 are alkyl groups having 1 to 4 carbon atoms. Or an alkenyl group).
  • the lubricant 2 is preferably a fluorinated organic lubricant containing at least one kind of perfluoropolyether having the structure of the following formula (2) from the viewpoint of adhesion to the surface of the magnetic layer and impregnation.
  • the magnetic layer is formed by applying a magnetic paint containing a ferromagnetic powder and a binder as main components, a fatty acid having 3 or more branches and 9 to 18 carbon atoms,
  • An object of the present invention is to provide a magnetic recording medium characterized by containing at least one ester compound (A) comprising an alcohol having 3 or more branches and 8 to 17 carbon atoms.
  • the present invention provides a magnetic recording medium characterized in that the ester compound (A) is at least one kind of an ester compound represented by the following general formula (1), and the compound is contained in the magnetic layer. is there.
  • n, m, s, and t are integers, and the sum of n and m and the sum of s and t are each 2 to 8, and R 1 and R 2 are alkyl groups having 1 to 4 carbon atoms or Alkenyl group.
  • the present invention relates to a magnetic recording medium having a magnetic layer formed by applying a magnetic coating solution containing a ferromagnetic powder on a nonmagnetic substrate, wherein the magnetic layer has a thickness of 0.1 to 0.5 m.
  • a lubricant an ester compound (A) composed of a fatty acid having 3 or more branches and 9 to 18 carbon atoms and an alcohol having 3 or more branches and 8 to 17 carbon atoms is used as the magnetic material.
  • the present inventors have realized a high-density magnetic recording medium capable of realizing a large-capacity floppy disk having a storage capacity of 100 MB or more using only a single magnetic layer.
  • the ester compound (A) as a lubricant added to the magnetic layer is represented by the following general formula (1)
  • n, m, s, and t are integers, and the sum of n and m and the sum of s and t are each 2 to 8, and R 1 and R 2 are alkyl groups having 1 to 4 carbon atoms or
  • An alkenyl group is preferably a compound represented by the formula:
  • the magnetic layer preferably contains the ester compound (A) in an amount of 5 to 25 parts based on 100 parts of the ferromagnetic powder in the magnetic layer.
  • the magnetic layer contains at least one compound selected from the group consisting of the above-mentioned ester compound (A) and a metal stone, a fatty acid, and a fatty acid amide which are solid at room temperature as a lubricant.
  • the lubricant contains a total of 10 to 25 parts of the lubricant based on 100 parts of the ferromagnetic powder in the magnetic layer.
  • the magnetic layer may contain at least one selected from a ferromagnetic alloy powder having a coercive force of 1500 to 300 Oersted or a hexagonal ferrite powder as a ferromagnetic powder. preferable.
  • the magnetic recording medium of the present invention described above has excellent electromagnetic conversion characteristics, slipperiness and durability, is single-layer and inexpensive.
  • the nonmagnetic substrate used in the present invention is preferably a plastic film.
  • plastic films include polyesters such as polyethylene terephthalate, polyolefins such as polypropylene, cellulose derivatives such as cellulose diacetate and cellulose triacetate, and synthetic resins such as polycarbonate, polyvinyl chloride, polyimide, polyamide, polysulfone, and polyether sulfone. Films and sheets can be mentioned.
  • a biaxially oriented film with a surface roughness of 1 to 6 nrri with a center line average roughness Ra of 1 to 6 nrri is used by adjusting the particle size and the amount of the filler. Is preferred. If Ra exceeds 6 nm, the purpose of increasing the recording density cannot be achieved because the smoothness of the recording layer formed by coating is impaired.
  • the ferromagnetic powder used in the present invention is a ferromagnetic powder having a specific surface area of 30 m 2 Zg or more.
  • the ferromagnetic powder include conventionally known Co-containing Fe 203 and Co-containing Fe Examples thereof include oxide magnetic powders such as 3 O 4 and barrier fluoride, and metal magnetic powders such as iron and Fe—Co—Ni. If the specific surface area is less than 30 m 2, the purpose of increasing the recording density cannot be achieved.
  • a ferromagnetic alloy powder having a small particle size and a high coercive force and a high CT s is preferable. Therefore, the specific surface area by the BET method is 30 to 80 m 2 / g, and the coercive force is 1 It is preferable to select a ferromagnetic fine powder in the range of 500 to 300 Oe. Examples of such ferromagnetic fine powders have a major axis length of 0.05 to 0.20 m, a crystallite size of 250 A or less, and a content ratio of Co element to Fe of 10 to 3 Ferromagnetic Fe alloy powder containing 0% and trace elements each of AL and Y in the range of 0 to 10% can be mentioned.
  • These magnetic powders may take various forms such as needles, granules, rice grains, and plates, and, if desired, various magnetic powders may be used alone or in combination.
  • various magnetic powders may be used alone or in combination.
  • the contribution of the magnetization amount of the perpendicular component is important, but a hexagonal ferrite suitable for perpendicular magnetic recording can be used together.
  • hexagonal ferrite which is harder than ferromagnetic alloy powder, has an effect on improving the durability of the magnetic layer and is preferably used.
  • the binder used for the magnetic layer known binders used for the binder of the magnetic layer of a usual coating type magnetic recording medium can be applied, and the following resins can be used.
  • polyurethane resins polyester resins, polycarbonate resins, rubber resins such as L-nonoxy resin, cellulose nitrate polymer, polybutyral resin, NBR, vinyl chloride vinyl acetate copolymer, vinylidene chloride copolymer And polyamide resins.
  • resins can be used alone or in combination.
  • polyisocyanate-based cross-linking agent can be used in combination with a polyisocyanate-based cross-linking agent to adjust the coating film properties to appropriate values.
  • polyisocyanate-based crosslinking agent examples include the following compounds.
  • diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, or trimethylolpropane and tolylene diisocyanate 3 moles of isocyanate (Nihon Polyurethane Co., Coronate, etc.).
  • additives such as a dispersant may be used in combination as necessary as other additives.
  • Use surfactant as dispersant Lecithin, a polymer dispersant, a silane coupling agent, a titanium coupling agent, a phosphate ester, and the like can be added.
  • the conductive non-magnetic powder used in the present invention bleeds out to the surface of the magnetic layer by carrying a lubricant, specifically by adsorbing, in addition to the conventional antistatic function required to prevent electrostatic damage.
  • a lubricant specifically by adsorbing
  • Any known conductive non-magnetic powder having an average particle size of 0.1 im or less can be applied as long as it has a function of preventing the occurrence of a lubricant and supplying a lubricant to the surface of the magnetic layer for a long period of time.
  • the amount of conductive nonmagnetic powders for Antistatic necessary to suppress below 1 0 1 ° Omega without charging the surface electrical resistance
  • the use of conductive non-magnetic powder which has both antistatic properties and a function as a carrier for lubricants, has made it possible to use a magnetic recording medium with a single-layer recording layer of 0. "! To 0.5 jlm. The ability to raise the quality of the product to a practical level with good balance.
  • the amount of the conductive non-magnetic powder added is set to b (parts per 100 parts of ferromagnetic powder), and the oil absorption is a (ml / 100 g). It is preferable that (axb ⁇ c) be in the range of 150 to 300 when the total added amount of the lubricant 1 and the lubricant 2 is part c. (Axb ⁇ c) When the force is less than 150, the lubricant bleeds out to the surface of the magnetic layer, and when it is 300 or more, the amount of the lubricant in the surface layer of the magnetic layer becomes insufficient and durability is deteriorated.
  • a conductive non-magnetic powder examples include a conductive carbon black, a metal powder and the like.
  • a conductive carbon black examples include a conductive carbon black, a metal powder and the like.
  • conductive inorganic powders such as metal oxides, metal carbonates, metal sulfates, metal nitrides, metal carbides, and metal sulfides, conductive materials such as Sb-doped Sn02, Sn-doped In203, and AI-doped Those coated with ZnO or the like can be applied.
  • ⁇ ⁇ ⁇ 2 TiO x, cerium oxide, tin oxide, tungsten oxide, ZnO, Zr02, Si02, iron arsenide, gateite, corundum, silicon nitride, titanium Carbide, boron nitride, copper oxide, carbonate
  • a material obtained by coating a conductive substance on gnesium, barium carbonate, calcium carbonate, barium sulfate, silicon carbide, titanium carbide, alumina, ⁇ alumina, ralumina, or the like can be used alone or in combination.
  • conductive carbon black is preferably used.
  • any material such as acetylene black, carbon black for color, furnace black, and Ketjen black can be used.
  • the average particle diameter is 5 to 80 nm, and the specific surface area is 200 to 1,500 m by the BET method. 2 / g, oil absorption 20 to 500 ml Z100 g, pH 2 to 10
  • the oil absorption of the present invention is the DBP oil absorption (AST M-D-241 4) measured using dibutyl phthalate (DBP) in place of linseed oil specified in JIS K5421.
  • DBP dibutyl phthalate
  • carbon black used are: B LACKPEARL S2000.1000, 900, 800, VUL CAN XC-72 manufactured by Cabot, RAVEN 8800, 8000, 7000 manufactured by Columbian Carbon, manufactured by Mitsubishi Chemical Corporation. # 3750 B, # 3750, # 3250B, # 325 0, # 950, # 850 B, # 650 B, # 45, # 40, # 5, MA-1 77, MA-7, Ketjen Black made by Lion Axio EC, Ketchen Black EC600 JD and the like. These carbon blacks can be used alone or in combination. Further, the surface of the carbon black may be treated with a dispersant or the like, or a part of the surface may be made into graphite. In any case, the content of the antistatic agent can be appropriately adjusted so as to conform to the product standards.
  • an inorganic powder acting as an abrasion-resistance improver for the magnetic layer and an abrasive for the magnetic head which is known as a non-magnetic powder
  • the average particle size of the inorganic powder used in this application may be selected according to the thickness of the magnetic layer, but in the present invention, the average particle size must be in the range of 0.1 to 0.6 m in relation to the thickness of the magnetic layer. is there. If the average particle size is larger than 0.6 m, the electromagnetic conversion characteristics are likely to be impaired, Abrasion resistance also decreases.
  • the average particle size is smaller than 0.1 m, not only the slipperiness, which is one of the original purposes, cannot be improved, but also the grinding power of the magnetic head is drastically reduced, resulting in deterioration of electric characteristics and destruction of the magnetic layer. It is easier to promote.
  • Non-magnetic powders used in this application include ⁇ ⁇ 02, ⁇ ⁇ O x, cerium oxide, tin oxide, tungsten oxide, Zn 0, Zr ⁇ 2, Sio2, and arsenic oxide.
  • Iron, goethite, corundum, silicon nitride, titanium carbide, boron nitride, copper oxide, magnesium carbonate, barium carbonate, calcium carbonate, barium sulfate, silicon carbide, titanium carbide, titanium alumina, alumina, r-alumina, chromium oxide, si-c Etc. can be used alone or in combination.
  • Examples of the particle shape include a granular shape, a spherical shape, and a gourd shape.
  • these non-magnetic powders may be coated with a conductive material to provide an antistatic function.
  • These abrasives are added in an amount of 5 to 20 parts by weight based on 100 parts by weight of the magnetic powder. If the amount is less than 5 parts by weight, sufficient durability cannot be obtained, and if it is more than 20 parts by weight, the density of the magnetic powder decreases and sufficient electromagnetic conversion characteristics cannot be obtained.
  • a lubricant is contained as described below in order to secure durability while satisfying various properties in the above-described magnetic layer.
  • the lubricant used is a lubricant composed of a high-supplied fatty acid or fatty acid derivative that is easily carried on the conductive non-magnetic powder and bleeds gradually over the surface for a long period of time, and a fluorine-based organic lubricant having good retention on the surface of the magnetic layer
  • the lubricant is composed of two types, the former being a double lubrication method in which the former is contained in the magnetic layer and the latter is contained in the surface and the surface of the magnetic layer, thereby not impairing the electromagnetic conversion characteristics of the thin magnetic layer. It ensures sufficient lubrication properties, especially durability.
  • the total amount of the lubricant 1 and the lubricant 2 added in the magnetic layer is in the range of 10 to 25 parts per 100 parts of the ferromagnetic powder.
  • the lubricant 2 moves from the inside of the magnetic layer to the surface to form a lubricating film on the surface, which lasts for a long time, but when the magnetic layer becomes thinner, the absolute amount of the lubricant existing inside the magnetic layer becomes insufficient, Forms a sufficient lubricating film on the surface become unable.
  • the magnetic layer having a thickness of 0.1 to 0.5 im of the present invention if the lubricant is less than 10 parts, the effect of maintaining the running durability as a lubricant is poor.
  • the lubricant bleeds out on the surface of the magnetic layer, plasticization becomes remarkable, and the magnetic layer becomes soft and the durability deteriorates.
  • a lubricant 1 higher fatty acids, fatty acid esters, fatty acid amides and the like can be applied.
  • the amount of the lubricant 2 added to the surface and the surface layer of the magnetic layer is selected to compensate for the shortage of the lubricant 1. Therefore, it is selected so that the total amount with the lubricant 1 is in the range described for the lubricant 1.
  • the amount of the lubricant 2 is usually in the range of 1 to several parts with respect to 100 parts of the ferromagnetic powder of the magnetic layer because it is contained in a limited area such as the surface or the surface layer.
  • the lubricant 2 examples include a fluorinated organic lubricant, specifically, a lubricant composed of a fluorinated polymer liquid, a fluorinated resin liquid or the like. Among them, those containing at least one or more perfluoropolyethers having the structure of the following chemical formula (2) are preferable from the viewpoint of reducing friction with a magnetic head and improving running stability.
  • the magnetic coating liquid of the present invention comprises the above-mentioned ferromagnetic powder, binder, conductive non-magnetic powder and lubricant as an organic solvent, For example, force to prepare by mixing with methyl ethyl ketone, methyl isobutyl ketone, toluene, cyclohexanone, tetrahydrofuran, etc.
  • a dispersant eg, lecithin, polymer dispersant, silane coupling agent, titanium
  • additives e.g., a thickener, a leveling agent, and an antibacterial agent
  • a coupling agent e.g., a phosphoric acid ester, and an antistatic agent
  • Ribon Black an antistatic agent
  • Various dispersing machines can be used for dispersing the coating material for the magnetic layer.
  • two-hole mill, three-roll mill, ball mill, pebble mill, sand grinder, An attritor, a high-speed impeller-dispersing machine, a high-speed impact mill, a kneader, a pressurized-feeder, a planetary mixer, a homogenizer, an ultrasonic dispersing machine or the like can be used alone or in combination.
  • the raw material used in the present invention may be divided in two or more steps. For example, a binder can be dividedly charged in a kneading step and a dispersing step, and a crosslinking agent such as a polyisocyanate can be added immediately before coating.
  • Conventionally known coating methods can be used for applying such a magnetic coating solution to the surface (one or both surfaces) of the nonmagnetic substrate.
  • an application method for example, air doctor coat, blade coat, air knife coat, squeeze coat, impregnation coat, reverse roll coat, gravure coat, die coat and the like can be used.
  • the coating amount is preferably in a range where the thickness of the coating film (magnetic layer) after drying and calendering treatment is 0.1 to 0.5 / m.
  • a conventionally known treatment can be used as the treatment after the application.
  • the lubricant 2 is applied to the surface of the cured magnetic layer to impregnate the surface and the surface layer with the lubricant 2 described above.
  • the lubricity with the magnetic head was greatly improved, and a practical level of durability was obtained in combination with the action of lubricant 1.
  • the lubricant used as a lubricant in the present invention comprises a fatty acid having 3 or more branches and 9 to 18 carbon atoms, and an alcohol having 3 or more branches and 8 to 1 carbon atoms. It is an ester compound (A).
  • the ester compound (A) is an ester compound represented by the following general formula (1),
  • n, m, s, and t are integers, and the sum of n and m and the sum of s and t are each 2 to 8, and R 1 and R 2 are alkyl groups having 1 to 4 carbon atoms or Alkenyl group.
  • the carboxylic acid constituting this ester compound has 9 to 18 carbon atoms and includes, for example, isononanoic acid (3,5,5 trimethylhexanoic acid), isotridecanoic acid (3,9,9 trimethyldecanoic acid) and the like.
  • the alcohol composing the ester compound has 8 to 17 carbon atoms and includes, for example, isooctyl alcohol (2,4,4 trimethylpentanol), isononyl alcohol (3,5,5 trimethylhexanol), Tridecyl alcohol (3,9,9 trimethyldecanol) and the like can be mentioned.
  • the ester compound of the general formula (1) can be used alone. It can also be used in combination with other lubricants.
  • a lubricant other than the general formula (1) higher fatty acids, fatty acid esters, fatty acid amides, silicone oils, modified silicone oils, paraffins, metallic soaps, waxes, etc., can be added irrespective of solids or liquids. It is preferable to include at least one selected from metal soap, fatty acid, and fatty acid amide which are solid at normal temperature. By using this solid lubricant together, the sliding property and durability at high temperatures are further improved. Although the reason is not clear, it is conceivable that general formula (1) tends to be taken into the magnetic layer and reduce the effective component of the surface layer to reduce the lubricity under a high-temperature atmosphere, and the solid lubricant decreases the lubricity of the surface layer. Can be presumed to have the effect of supplementing
  • solid lubricants include, for example, calcium laurate, zinc laurate, calcium stearate, zinc stearate, lead stearate, calcium ricinoleate, zinc ricinoleate, acetic acid, lauric acid, myristic acid, Palmitic acid, spearic acid, spearamide, oleic acid amide and the like can be mentioned.
  • the compounding amount of the general formula (1) is preferably in the range of 10 to 25 parts with respect to 100 parts of the ferromagnetic powder when used alone, and when the other lubricant is used in combination, the general formula (1) Is
  • the effect can be exhibited by including at least 5 parts with respect to 100 parts of the ferromagnetic powder and mixing at least 10 parts of the lubricant in total. If the amount is less than 10 parts, the friction with the magnetic head increases, the driving torque increases, and not only running stability deteriorates, but also running durability deteriorates. If the amount is more than 25 parts, adverse effects such as premature drop of the lubricant on the surface of the magnetic layer and softening of the coating film due to the plasticizing action to lower the durability are caused.
  • an ester composed of a fatty acid having a linear or branched chain of 2 or less When an ester composed of a fatty acid having a linear or branched chain of 2 or less is used in place of the general formula (1), an ester composed of a fatty acid having a carbon number of 12 or less has a large evaporation loss under a high temperature atmosphere, and the The durability of the recording medium decreases, and the ester composed of fatty acids having 13 or more carbon atoms deteriorates the fluidity in a low temperature range and impairs running stability.
  • the number of branches is 2 or less, it is not possible to form an ester that can satisfy both the evaporation loss under a high-temperature atmosphere and the fluidity at a low temperature.
  • the number of branches indicates the number of alkenyl or alkenyl groups substituted at any position in the main chain of long-chain fatty acid or long-chain alcohol.
  • the magnetic recording medium of the present invention has low driving torque and excellent running stability and durability, it is useful as, for example, a high recording density magnetic tape or a floppy disk which requires high reliability.
  • the temperature and humidity conditions of the following four cases were switched every 6 hours in the following order, and a continuous rotation test was conducted by installing a disk drive in a thermostat operated in one cycle.
  • the continuous rotation test uses a 3.5-inch FDDFD 1337C manufactured by NEC Corporation as a floppy disk drive, and operates at normal rotation speed (360 rpm) and normal rotation speed. At the tension, the head was put on the outer circumference (track 00) of the sample magnetic disk, and the sample magnetic disk was continuously rotated and run on the same track.
  • a mixture having the following composition was kneaded with a wet disperser to prepare a magnetic paint.
  • Ferromagnetic metal alloy powder (specific surface area 50 m 2 / g, Hc 1650 0e) 100 parts conductive non-magnetic powder carbon black: DBP oil absorption 495 ml / 100 g, average particle diameter 30 nm)
  • a disc medium having a diameter of 90 mm was punched out, and perfluoropolyether (average molecular weight: 9500) was applied as a lubricant 2 to both sides by spin coating to prepare a disc medium.
  • perfluoropolyether average molecular weight: 9500
  • the specific gravity of the magnetic coating film is less than 2.1, and the coating conditions are adjusted so that the weight increase by spin coating is 30 g on one side, so that it becomes 1 part per 100 parts of ferromagnetic metal alloy powder. The amount of application was determined.
  • a floppy disk sample having the same configuration as in Example 1 was prepared in the same manner as in Example 1 except that the amount of the lubricant 1 in the magnetic paint was changed to 13 parts.
  • a floppy disk sample having the same configuration as in Example 1 was prepared in the same manner as in Example 1, except that the amount of the lubricant 1 in the magnetic paint was changed to 21 parts.
  • Example 1 A floppy disk sample having the same structure as in Example 1 was prepared except that the amount of the lubricant 1 in the magnetic paint was 21 parts and the amount of the conductive non-magnetic powder was 8 parts in Example 1. Created as in Example 1.
  • a floppy disk sample having the same structure as in Example 1 was prepared in the same manner as in Example 1 except that the magnetic paint in Example 1 was applied to a polyethylene terephthalate film having a Ra force on one side of ⁇ 1 nm and a Ra on the other side of 5 nm. Created in the same way. The evaluation was performed on a magnetic film formed on a 1 nm Ra surface.
  • Example 1 instead of the ferromagnetic alloy powder (specific surface area: 50 m 2 Zg, H c 1650 O e) in the magnetic paint, the specific surface area was also 50 m 1 /, and H c was 2300 O e.
  • Example 1 instead of adding 16 parts of a mixture of hexadecyl balmitate and isooctyl stearate as the lubricant 1 in the magnetic paint, isononanoic acid A sample of a floppy disk having the same constitution as in Example 1 was prepared in the same manner as in Example 1, except that 6 parts of phenyl and 10 parts of a mixture of hexadecyl palmitate and isooctylspartate were added.
  • Example 1 was repeated except that 16 parts of nonyl isononanoate was used in place of adding 16 parts of a mixture of hexadecyl balmitate and isooctyl stearate as the lubricant 1 in the magnetic paint.
  • a sample of the floppy disk having the same configuration was prepared in the same manner as in Example 1.
  • a floppy disk sample having the same configuration as in Example 1 was prepared in the same manner as in Example 1 except that the amount of the lubricant 1 in the magnetic paint was changed to 10 parts.
  • a floppy disk sample having the same configuration as in Example 1 was prepared in the same manner as in Example 1 except that the amount of the lubricant 1 in the magnetic paint was changed to 23 parts.
  • Example 1 A floppy disk sample having the same configuration as in Example 1 was prepared except that the amount of conductive non-magnetic powder in the magnetic paint was 4.5 parts and the amount of lubricant 1 was 8 parts. Created in the same way as 1.
  • Example 1 A floppy disk sample having the same configuration as in Example 1 was prepared except that the amount of conductive non-magnetic powder in the magnetic paint was 9 parts and the amount of lubricant 1 was 25 parts in Example 1. Created in the same way as 1.
  • Example 1 the magnetic paint was applied to polyethylene terephthalate having Ra force of 0 nm.
  • a floppy disk sample having the same configuration as in Example 1 was prepared in the same manner as in Example 1 except that the film was applied to the film.
  • Example 1 A sample of a floppy disk having the same configuration as in Example 1 was prepared in the same manner as in Example 1 except that lubricant 2 (perfluoropolyether) was not added in Example 1.
  • lubricant 2 perfluoropolyether
  • Table 1 below shows the main conditions of each sample described above.
  • Tables 2 to 5 show the evaluation results.
  • Table 2 shows the measurement results of the electromagnetic conversion characteristics
  • Table 3 shows the measurement results of the driving torque for evaluating the slipperiness
  • Table 4 shows the evaluation results of the acceleration durability
  • Table 5 shows the evaluation results of the cycle durability.
  • the evaluation was that the 2F output was 350mV or more for the electrical characteristics and the resolution (2F / 1F) was 0.50 or more.
  • the drive torque was 40g-cm or less
  • the acceleration durability was 3 points or more
  • the cycle was good.
  • Regarding the durability based on the criteria of 800,000 passes or more, each evaluation item was judged to be good for each evaluation item.
  • Example 1 is a reference example of evaluation, and shows excellent characteristics in all evaluations.
  • Example 2 in which the amount of the lubricant 1 added was reduced, the durability tended to be lower than that of the sample in the example 1, but this was because the amount of the lubricant added was small. This is presumed to be due to the fact that the formation of the lubricating film on the surface of the magnetic layer became insufficient.
  • the durability is in a range where there is no practical problem in this range. Other characteristics are almost the same as those of the first embodiment.
  • Example 1 for the sample of Example 4 in which the amount of conductive non-magnetic powder added was increased.
  • the output level of the electromagnetic conversion characteristics tended to decrease slightly, but this was because the large amount of conductive non-magnetic powder added prevented the dispersion of the magnetic powder and adversely affected the filling property. Conceivable. In this range, the driving torque, that is, the slipperiness and the durability were not practically problematic but tended to decrease.
  • Example 5 In the sample of Example 5 on the surface side of the nonmagnetic substrate having good surface smoothness, the electromagnetic conversion characteristics tended to be improved as compared with Example 1, but this was because the surface smoothness of the nonmagnetic substrate was improved. It is considered that the smoothness of the magnetic layer was improved due to the rise, and the space opening with the magnetic head was reduced. In this sample, the driving torque tended to increase, that is, the slipperiness decreased, but there was no change in durability.
  • the sample of Example 6, which uses a magnetic powder with an increased He of the magnetic powder and reduces the thickness of the magnetic layer to achieve higher densities, does not reach 350 mV in the 2F output, but compared to Example 1.
  • the 2FZ1F ratio has been greatly improved, making the medium suitable for high-density recording.
  • the durability tends to decrease due to the decrease in the thickness, it is in a range where there is no practical problem due to the increase in the ratio of the lubricant 1 added.
  • a mixture having the following composition was kneaded with a wet disperser to prepare a magnetic paint.
  • Carbon black 3 parts Abrasives (Hi-Alumina with average particle diameter 0.3 m) 1 2 parts Dispersant (lecithin) 2 parts Sulfonic acid group-containing vinyl chloride resin (manufactured by Zeon Corporation MR-1110) 13 parts Polyurethane (Kyowa Hakko Co., Ltd. Esten 570F) 8 parts Polyisocyanate (Nippon Polyurethanes Co.
  • Lubricant 3 (isononyl isononanoate) 1 2 parts Lubricant 4 (calcium stearate) 2 parts Solvent (mixed solvent of toluene and cyclohexanone) 300 parts
  • Solvent mixed solvent of toluene and cyclohexanone 300 parts
  • a magnetic recording medium was prepared on a 75 m polyethylene terephthalate film by dry-calendering, drying, calendaring, and heating so that the coating thickness after drying-calendering would be 0.4 m.
  • a floppy disk sample was prepared by a known method.
  • Example 9 A sample of a floppy disk having the same structure as in Example 9 except that the addition amount of the lubricant 3 (nonyl isononanoate) in the magnetic paint was changed from 12 parts to 20 parts in Example 9, Created in the same way.
  • the lubricant 3 nonyl isononanoate
  • Example 9 12 parts of the lubricant 3 (nonyl isononanoate) in the magnetic paint was changed to 20 parts of nonyl isotridecanoate, and further 12 parts of the abrasive (average particle diameter 0.3 m) in the magnetic paint was used. Hexagonal Valium-Fillite powder Specific surface area 33 m2 Zg, Hc2200Ee) Instead of reducing to 6 parts, the same composition as in Example 9 was used except that 6 parts were used to prepare the paint. A floppy disk sample was prepared in the same manner as in Example 9.
  • Example 9 was repeated except that the lubricant 3 (nonyl isononanoate) 12 parts in the magnetic paint was changed to the mixed lubricant of 6 parts of nonyl nonononate and 6 parts of 2-hexyldecyl palmitate in Example 9.
  • Example 9 The same procedure as in Example 9 was carried out except that the nonyl isononanoate as the lubricant 3 in the magnetic paint in Example 9 was replaced with 2-year-old octyl decyl balmitate. Was created.
  • a floppy disk sample having the same structure as in Example 9 was prepared in the same manner as in Example 9, except that 2-ethylethylhexylbehenate was used as the nonyl isononanoate 3 as the lubricant 3 in the magnetic paint. did.
  • a floppy disk sample having the same configuration as in Example 9 was prepared in the same manner as in Example 9 except that the addition amount of the nonyl isononanoate of the lubricant 3 in the magnetic paint was changed from 12 parts to 3 parts in Example 9. Created.
  • Example 11 A sample of a floppy disk having the same configuration as in Example 11 was prepared in Example 11 except that the addition amount of nonyl isotridecanoate as the lubricant 3 in the magnetic paint was changed from 20 parts to 30 parts. Created in the same way as

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  • Health & Medical Sciences (AREA)
  • Emergency Medicine (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

La présente invention concerne un support d'enregistrement magnétique comportant un substrat non magnétique porteur d'une couche magnétique résultant de l'application d'un liquide magnétique chargé d'une poudre ferro-magnétique. Ce support est caractérisé en ce que le substrat non magnétique pésente une rugosité superficielle (Ra) de 1 à 6 nm entre médianes, l'aire de surface spécifique BET de la poudre ferro-magnétique étant de 30 m2/g. L'épaisseur de la couche magnétique est de 0,1 à 0,5 νm. La couche magnétique est faite d'un lubrifiant (1) comprenant un acide gras supérieur ou un dérivé d'acide gras à raison de 10 à 25 parties pour 100 parties de poudre magnétique, et d'une poudre non magnétique électro-conductrice dont le diamètre particulaire moyen n'excède pas 0,1 νm et qui supporte le lubrifiant (1). Elle est en outre enduite et imprégnée d'un lubrifiant fluoré. L'invention concerne également un support d'enregistrement magnétique comportant une couche support élastique sur lequelle est déposée une couche magnétique comprenant essentiellement une poudre ferro-magnétique et un liant. En l'occurrence, la couche magnétique contient un adjuvant de fabrication constitué d'un composé ester (A) dérivé d'un acide gras portant au moins 3 ramifications et 9 à 18 atomes de carbone et d'un alcool portant au moins 3 ramifications et 8 à 17 atomes de carbone.
PCT/JP2000/004211 1999-06-28 2000-06-27 Support d'enregistrement magnetique WO2001001402A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU55699/00A AU5569900A (en) 1999-06-28 2000-06-27 Magnetic recording medium

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP18186599 1999-06-28
JP11/181865 1999-06-28
JP2000002498 2000-01-11
JP2000/2498 2000-01-11

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WO2001001402A1 true WO2001001402A1 (fr) 2001-01-04

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108380863A (zh) * 2017-02-03 2018-08-10 株式会社神户制钢所 粉末冶金用混合粉末及其制造方法

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6484432A (en) * 1987-09-25 1989-03-29 Konishiroku Photo Ind Magnetic disk
JPH04159248A (ja) * 1990-10-24 1992-06-02 Hitachi Maxell Ltd 脂肪酸エステルおよびこの脂肪酸エステルを用いた磁気記録媒体
JPH04186523A (ja) * 1990-11-20 1992-07-03 Matsushita Electric Ind Co Ltd 磁気記録媒体
JPH05174363A (ja) * 1991-12-20 1993-07-13 Kao Corp 磁気記録媒体
JPH0689426A (ja) * 1992-07-22 1994-03-29 Toshiba Corp 磁気記録媒体
JPH07153062A (ja) * 1993-12-01 1995-06-16 Sumitomo 3M Ltd 磁気記録媒体およびその製造方法
JPH07296370A (ja) * 1994-04-21 1995-11-10 Fuji Photo Film Co Ltd 磁気記録媒体
JPH07320254A (ja) * 1994-05-26 1995-12-08 Sony Corp 磁気記録媒体
EP0869482A1 (fr) * 1997-03-31 1998-10-07 Fuji Photo Film Co., Ltd. Support d'enregistrement magnétique
JPH10275327A (ja) * 1997-03-31 1998-10-13 Victor Co Of Japan Ltd 磁気記録媒体

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6484432A (en) * 1987-09-25 1989-03-29 Konishiroku Photo Ind Magnetic disk
JPH04159248A (ja) * 1990-10-24 1992-06-02 Hitachi Maxell Ltd 脂肪酸エステルおよびこの脂肪酸エステルを用いた磁気記録媒体
JPH04186523A (ja) * 1990-11-20 1992-07-03 Matsushita Electric Ind Co Ltd 磁気記録媒体
JPH05174363A (ja) * 1991-12-20 1993-07-13 Kao Corp 磁気記録媒体
JPH0689426A (ja) * 1992-07-22 1994-03-29 Toshiba Corp 磁気記録媒体
JPH07153062A (ja) * 1993-12-01 1995-06-16 Sumitomo 3M Ltd 磁気記録媒体およびその製造方法
JPH07296370A (ja) * 1994-04-21 1995-11-10 Fuji Photo Film Co Ltd 磁気記録媒体
JPH07320254A (ja) * 1994-05-26 1995-12-08 Sony Corp 磁気記録媒体
EP0869482A1 (fr) * 1997-03-31 1998-10-07 Fuji Photo Film Co., Ltd. Support d'enregistrement magnétique
JPH10275327A (ja) * 1997-03-31 1998-10-13 Victor Co Of Japan Ltd 磁気記録媒体

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108380863A (zh) * 2017-02-03 2018-08-10 株式会社神户制钢所 粉末冶金用混合粉末及其制造方法
CN108380863B (zh) * 2017-02-03 2021-07-13 株式会社神户制钢所 粉末冶金用混合粉末及其制造方法

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