JP2003178417A - Flexible magnetic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress transfer of lubricant of a flexible magnetic recording medium to a master carrier for magnetic transfer by which information is recorded, while durability and damage resistance of the magnetic recording medium are maintained. <P>SOLUTION: The flexible magnetic recording medium has a coating layer containing a magnetic layer and a non-magnetic layer and having 0.03 to 0.3 ml/g surface pore volume. <P>COPYRIGHT: (C)2003,JPO

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-density magnetic recording medium.
Magnetic disk for high capacity data recording
Preformat signal is recorded by magnetic transfer suitable for
The present invention relates to a flexible magnetic recording medium. [0002] At present, the data of personal computers, etc.
As a recording medium for recording data, a flexible magnetic disk
2HD flexible disk (hereinafter referred to as 2H)
D-FD) is often used, and many par
Disk drive for 2HD-FD on Sonar computer
Is installed as standard. However, in recent years,
The amount of data has increased dramatically, with 2HD-FD
In many cases, the recording capacity is not sufficient. Therefore, easily
Desirable to increase the capacity of flexible magnetic disk media that can be handled
It is. In response to such demands, magnetic disk media
Various technologies have been developed to increase the recording capacity of
Recording capacity of 2HD-FD even for flexible magnetic disk media
It has a recording capacity far exceeding, for example, 100MB or more.
Magnetic disk media have been put into practical use. Such a large
High-capacity magnetic disk media are used for high-density data recording and high
To support high-speed data transfer, magnetic disk media
Rotates at high speed and floats by rotating the magnetic disk medium
A magnetic disk device using a quasi-levitation type magnetic head
Therefore, data recording / reproduction is performed. As is well known, magnetic disk media are very
Important data (information) may be recorded on
In addition, data recording / playback is usually repeated.
is there. Therefore, it is excellent for large-capacity magnetic disk media.
Naturally, durability is required. In addition,
When recording / reproducing data, the magnetic head of the magnetic disk device
It is preferable that the burden on the door is small. Such a request
In contrast, the emergence of magnetic disk media with superior characteristics
The present is desired. SUMMARY OF THE INVENTION A magnetic disk medium is made high.
Rotate at high speed and move the magnetic head against the surface for a predetermined time
(For example, 200 to 300 hours in a high temperature environment)
Will cause damage to the magnetic disk media and data
May not be recorded or played back, and an error may occur.
The One of the causes of scratches on magnetic disk media
As a result, the lubricant in the magnetic disk medium is volatilized by running.
As a result, the lubrication performance is lowered. Snow
In other words, the lubricant is great for the durability and scratch resistance of magnetic disk media.
Is not necessary for magnetic disk media.
It is indispensable. However, on the other hand, magnetic disk media include
Servo signal for tracking, address information signal, playback clock
So-called preformat signals such as lock signals
Recorded by magnetic transfer using a master copy carrier
However, the lubricant on the magnetic disk medium is magnetic during this recording.
Transfer it to the transfer master carrier and store it on it.
It is difficult to uniformly record magnetic transfer signals on a disk medium.
It is one of the causes. That is, the lubricant is resistant to magnetic disk media.
It is necessary to maintain durability and scratch resistance.
Preformat signal by master carrier for magnetic transfer
Is one of the obstacles when recording on many magnetic disk media
It has become. The present invention has been made in view of the above circumstances.
While maintaining the durability and scratch resistance of magnetic recording media,
Simultaneously record preformat signal by magnetic transfer
The magnetic recording medium lubricant is transferred to the magnetic transfer master carrier.
To increase the number of continuous magnetic transfer times
Aiming to provide a flexible magnetic recording medium capable of
It is intended. SUMMARY OF THE INVENTION The flexible magnet of the present invention.
The air-recording medium has an uneven pattern according to the information to be transferred.
The information is transferred by closely contacting the magnetic transfer master carrier.
A film having a coating layer including a magnetic layer and a nonmagnetic layer to be copied.
The surface pore volume of the coating layer of the rewritable magnetic recording medium
It is characterized by being in the range of 0.03-0.3 ml / g
Is. The surface pore volume of the coating layer is 0.05 to
More preferably, it is in the range of 0.25 ml / g. The flexible magnetic recording medium of the present invention comprises:
Flexible having a coating layer including a magnetic layer and a non-magnetic layer
The surface pore volume of the coating layer of the magnetic recording medium is set to 0.03 to 0.03.
Since it is in the range of 0.3 ml / g, an appropriate amount in the coating layer
The surface of the magnetic recording medium while retaining the lubricant
Magnetic material can be supplied properly for a long period of time.
It is possible to improve the durability and scratch resistance of recording media.
The Also, when transferring flexible magnetic recording media,
Lubricant transferred to the star carrier is due to pores on the coating layer surface.
It is sucked in by capillary action and returned to the magnetic recording medium.
Transfer and accumulation on the star carrier can be suppressed
Therefore, the number of continuous magnetic transfer times is longer than before.
be able to. DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
I will explain. Flexible magnetic recording for magnetic transfer of the present invention
The recording medium has a coating layer including a magnetic layer and a nonmagnetic layer.
The surface pore volume of the coating layer of the rewritable magnetic recording medium is set to 0.
The range is from 03 to 0.3 ml / g. The surface pore volume of the coating layer is contained in the coating layer.
Select carbon black or various abrasives, coating liquid
Adjustment of dispersion state, selection of application method, application / drying conditions
For selection and selection of calendar processing conditions
Therefore, it can be in the range of 0.03-0.3 ml / g.
Yes. Use in the magnetic layer and nonmagnetic layer of the present invention
Carbon black that can be
, Rubber thermal, color black, acetylene rubber
A rack or the like can be used. Specific surface area is 5-50
0m ² / G, DBP oil absorption is 10 to 400 ml / 100
g, particle diameter is 5m to 300mμ, pH is 2 to 10, including
Water percentage is 0.1-10%, tap density is 0.1-1 g / c
c is preferred. Carbon black tool used in the present invention
As a physical example, manufactured by Cabot, BLACKPEAR
LS 2000, 1300, 1000, 900, 90
5, 800, 700, VULCAN XC-72, Asahi
Made by Bonn, # 80, # 60, # 55, # 50, # 3
5, Mitsubishi Chemical Industries, # 3250B, # 2400B,
# 2300, # 900, # 1000, # 30, # 40,
# 10B, Columbia Carbon, CONDUCTE
X SC, RAVEN 150, 50, 40, 15, RA
VEN-MT-P, manufactured by Japan EC, Ketjen Black
EC etc. are mentioned. The carbon black used in the present invention is a dispersant.
Surface treatment, grafting with resin, etc.
Even if part of the surface is graphitized, it does not matter
Absent. Carbon black, magnetic paint, non-magnetic paint
It can be dispersed with a binder before adding to the coating material.
Absent. These carbon blacks can be used alone or as appropriate.
Can be used together. Can be used in the present invention
For example, carbon black ("carbon black flights
Can be referred to the "Carbon Black Association")
Yes. Carbon black adjusts the surface pore volume.
In addition to the above, the magnetic layer is antistatic and has a low coefficient of friction.
Reduced, added light shielding, improved film strength, etc.
Reduce the surface electrical resistance Rs and reduce the light transmittance.
As well as the desired micro-Vickers hardness
Work to bring about the degree of storage and lubricant storage
Yes, these differ depending on the carbon black used
Therefore, it is preferable to adjust the type and usage according to the purpose.
Good. The content of carbon black in the magnetic layer is
0.1 to 20 weight with respect to the ferromagnetic powder contained in the magnetic layer
% Is preferable. Also, in the nonmagnetic layer
The amount of carbon black contained in the nonmagnetic layer
It is preferably in the range of 3 to 25% by weight with respect to the magnetic powder.
Good. Abrasives are known for use in magnetic recording media.
Abrasives can be used, for example, fused alumina,
Silicon carbide, chromium oxide, cerium oxide, α-iron oxide,
Corundum, artificial corundum, silicon nitride, titanium car
Bite, titanium oxide, silicon dioxide, boron nitride, zaku
Uses rock stone, emery (main components: corundum and magnetite), etc.
Can be used. The preferred average particle size of these abrasives is
Adjustment of the amount of abrasive used, dispersion state of coating solution, selection of coating method
Selection, application / drying conditions, calendar processing conditions
Because it varies depending on
Preferably having a size of -3 μm, preferably 0.1-1.5 μm
The thing of the magnitude | size of is more preferable. These abrasives are necessary
It can be added to either the magnetic layer or the non-magnetic layer depending on
Absent. The surface shape was controlled by adding to the nonmagnetic layer.
In other words, the protruding state of the abrasive can be controlled. The above-described carbon black and abrasives are coated.
The surface pore volume of the fabric layer is finally 0.03 to 0.3 ml /
If it can be adjusted to the range of g,
Both can be used as needed, and in the magnetic layer
Even if it is included in the nonmagnetic layer, it is included in both
May be. Lubricants usable in magnetic recording media
Is not particularly limited, and is used for various magnetic recording media
All known ones are available. For example, carbon number 10
~ 24 monobasic fatty acids (even if they contain unsaturated bonds,
And may be branched) and their metal salts (L
i, Na, K, Cu, etc.) or having 12 to 22 carbon atoms
Monovalent, divalent, trivalent, tetravalent, pentavalent, hexavalent alcohol
May contain a union bond or may be branched), charcoal
12 to 22 prime alkoxy alcohol, 10 to 10 carbon atoms
24 monobasic fatty acids (even if they contain unsaturated bonds,
May be branched) and monovalent, 2 to 12 carbon atoms
, Trivalent, tetravalent, pentavalent, hexavalent alcohol (unsaturated bonds
Any one of them may be included or branched)
Mono-fatty acid ester or di-fatty acid esthetic
Or tri-fatty acid ester, alkylene oxide polymerization
Fatty acid esters of monoalkyl ethers, 8 carbon atoms
-22 fatty acid amide, C8-22 fatty acid amine
Etc. can be used. Specifically, capric acid, caprylic acid,
Uric acid, myristic acid, palmitic acid, stearin
Acid, behenic acid, oleic acid, elaidic acid, linole
Fatty acids such as acid, linolenic acid, isostearic acid,
Chill stearate, octyl stearate, amyl stearate
Allate, isooctyl stearate, butyl myristate
Octyl myristate, butoxyethyl stearate
, Butoxydiethyl stearate, 2-ethylhexyl
Silstearate, 2-octyldodecyl palmitate
, 2-hexyldecyl palmitate, isohexade
Silstearate, oleyl oleate, dodecyl stearate
Allate, tridecyl stearate, oleic oleate
S, such as neopentyl glycol didecanoate
Tells, olein alcohol, stearyl alcohol,
Examples include alcohols such as lauryl alcohol
The Further, alkylene oxide type, glycerin
-Based, glycidol-based, alkylphenol ethylene
Nonionic surfactants such as oxide adducts, cyclic amino acids
, Ester amide, quaternary ammonium salts, hydan
Toin derivatives, heterocycles, phosphonium or sulfoni
Cationic surfactants such as ums, carboxylic acids, sulfur
Phonic acid, phosphoric acid, sulfate ester group, phosphate ester group
Anionic surfactants that contain acidic groups such as amino acids
, Aminosulfonic acids, amino alcohol sulfuric acid or
Are amphoteric boundaries such as phosphate esters and alkylbedine types
Surfactants and the like can also be used. The organic solvent used in the present invention can have any ratio.
With acetone, methyl ethyl ketone, methyl isobutyl ketone
, Diisobutyl ketone, cyclohexanone, isophor
Ketones such as Ron and tetrahydrofuran, methanol
Ethanol, propanol, butanol, isobuty
Alcohol, isopropyl alcohol, methylcyclo
Alcohols such as hexanol, methyl acetate,
Chill, isobutyl acetate, isopropyl acetate, ethyl lactate
, Esters such as glycol acetate, glycol dimethyl ester
Chill ether, glycol monoethyl ether, dioxane
Glycol ethers such as sun, benzene, and true
, Xylene, cresol, chlorobenzene, etc.
Aromatic hydrocarbons, methylene chloride, ethylene chlora
Id, carbon tetrachloride, chloroform, ethylene chlorohydride
Chlorinated hydrocarbons such as phosphorus and dichlorobenzene, N,
Use N-dimethylformamide, hexane, etc.
You can. These organic solvents are not necessarily 100% pure
It is not necessary that there are isomers, unreacted substances, by-products
Contains impurities, decomposition products, oxides, moisture, etc.
There is no problem. These impurities are preferably 30% by weight or less.
Preferably, it is preferably 10% by weight or less.
Yes. The organic solvent used in the present invention is magnetic if necessary.
The type and amount of use can be changed between the non-magnetic layer and the non-magnetic layer.
Yes. For example, volatile in the magnetic layer to improve surface properties
To improve the stability of the coating.
Solvents with high surface tension (cyclohexanone, geo
Non-magnetic to increase the degree of filling
Use a solvent with a high solubility parameter for the layer, etc.
can do. The magnetic recording medium has a surface pore volume of the coating layer.
Except that the product is in the range of 0.03-0.3 ml / g
The structure is basically the same as that of a known magnetic recording medium.
Above all, a substantially non-magnetic lower layer and formed on it
Ferromagnetic powder or ferromagnetic hexagonal ferrite fine powder
Magnetic recording medium having a magnetic layer dispersed in an inner
Can be suitably used. This magnetic recording medium
In addition to forming a thin layer with a thickness of 0.5 μm or less, the high strength
Excellent surface smoothness. Therefore, this magnetic recording medium
High recording density and higher durability
And an excellent magnetic recording medium having good performance can be obtained. Hereinafter, this magnetic recording medium is suitable for use.
An example will be described. [Magnetic layer] Coercive force of magnetic layer of magnetic recording medium
Hc is preferably 143 kA / m (1800 Oe) or more.
More preferably 159 kA / m (2000 Oe) or less
Furthermore, 183 to 279 kA / m (2300
˜3500 Oe) is preferred. 143
High recording density is improved by using kA / m or more.
Can be achieved. (Ferromagnetic powder) Ferromagnetic material used for upper magnetic layer
Ferrous powder can be ferromagnetic metal powder or hexagonal ferrite
Tow powder is preferably used. As ferromagnetic metal powder
Preferably have a major axis length of 150 nm or less. Also,
Hexagonal ferrite powders of 35nm or less
preferable. The ferromagnetic metal powder is mainly composed of α-Fe.
Ferromagnetic alloy powder is preferred. These ferromagnetic metal powders
In addition to predetermined atoms, Al, Si, S, Sc, Ca, T
i, V, Cr, Cu, Y, Mo, Rh, Pd, Ag, S
n, Sb, Te, Ba, Ta, W, Re, Au, Hg,
Pb, Bi, La, Ce, Pr, Nd, Sm, P, C
including atoms such as o, Mn, Zn, Ni, Sr, B
Good. In particular, Al, Si, Ca, Y, Ba, La, N
At least one of d, Sm, Co, Ni, and B is α-Fe.
It is preferable to include other than Co, Y, Al, Nd, S
More preferably, at least one of m is included. Co's
The content is preferably 40 atomic% or less with respect to Fe.
More preferably, it is 15-35 atomic%, Furthermore, 20
It is preferably in the range of ˜35 atomic%. Y content
Is preferably 1.5 to 12 atomic% with respect to Fe
More preferably, it is 3-10 atomic%, Furthermore, 4-9
A range of atomic% is preferred. Al content is
It is preferable that it is 1.5-30 atomic% with respect to Fe
More preferably, it is 5-20 atomic%, Furthermore, 8-15
A range of atomic% is preferred. Also these strong
Magnetic powder includes dispersants, lubricants, surfactants, antistatic
Treatment may be carried out in advance before dispersing with an agent or the like. As the ferromagnetic hexagonal ferrite, barium
Ferrite, strontium ferrite, lead ferrite
, Calcium ferrite and their various substitutions
Body, Co-substituted body and the like. Specifically, Magnet
Plumbite type barium ferrite and stront
Magnesium whose particle surface is coated with um ferrite and spinel
Toplumbite type ferrite and some spinel phase
Contained composite magnetoplumbite type barium ferrule
And strontium ferrite.
In addition to predetermined atoms, Al, Si, S, Nb, T
i, V, Cr, Cu, Y, Mo, Rh, Pd, Ag, S
n, Sb, Te, W, Re, Au, Bi, La, Ce,
Pr, Nd, P, Co, Mn, Zn, Ni, B, Ge
Any atom may be included. In general, Co-Zn, Co
-Ti, Co-Ti-Zr, Co-Ti-Zn, Ni-
Ti-Zn, Nb-Zn-Co, Sn-Zn-Co, S
What added elements, such as n-Co-Ti and Nb-Zn
Can be used. Depending on the raw material and manufacturing method,
Some contain pure products. Hexagonal plate diameter is preferred for powder size
The average plate diameter is preferably 10 to 35 nm. The ferromagnetic powder contained in the magnetic layer is obtained by the BET method.
If expressed in terms of specific surface area, usually 45-80m ² / G
The The crystallite size of ferromagnetic metal powder is usually 8-18n
m, preferably 10 to 18 nm.
More preferably, it is in the range of 11 to 17.5 nm.
Good. The average major axis length of the ferromagnetic metal powder is 30 to 150.
preferably in the range of nm, 30-100 nm
A range is more preferable. Needle shape of ferromagnetic metal powder
The ratio is preferably in the range of 3-15, 5-12
More preferably, it is the range. Saturation of ferromagnetic powder
The chemical σs is usually 100 to 200 A · m. ² / Kg (100
~ 200emu / g), 120 ~ 180A
・ M ² / Kg (120-180 emu / g)
More preferably. The plate ratio of hexagonal ferrite is
It is usually in the range of 2-20, and in the range of 2-5
More preferred. The saturation magnetization σs is usually 30 to 70 A.
・ M ² / Kg (30-70 emu / g),
40-60A ・ m ² / Kg (40-60emu / g)
A range is more preferable. Ferromagnetic powder is needed
Surface treatment with Al, Si, P or their oxides
You may give reason. The SFD of the ferromagnetic powder itself is preferably small
Moreover, 0.8 or less is preferable. That is, H of ferromagnetic powder
It is preferable to reduce the distribution of c. Especially SFD
If it is 0.8 or less, the electromagnetic conversion characteristics are good and the output is high.
In addition, the magnetization reversal is sharp and the peak shift is small.
Therefore, it is suitable for high density digital magnetic recording. Hc minutes
As a method of reducing the cloth, in ferromagnetic metal powder
Improve the particle size distribution of goethite, do not prevent sintering
Which way is there. [Nonmagnetic layer (lower layer)] Lower layer of magnetic recording medium
The structure should be limited if it is substantially non-magnetic
Although it is not a thing, it usually consists of at least resin and is preferred
Or powder such as inorganic powder or organic powder in the resin.
Examples are dispersed. The inorganic powder is preferably
Non-magnetic powder, but the lower layer is substantially non-magnetic
Magnetic powder can also be used. The lower layer is substantially non-
Being magnetic means that the electromagnetic conversion characteristics of the upper layer are substantially reduced.
It is said that the lower layer is allowed to have magnetism within the range
Meaning. (Nonmagnetic powder) As the nonmagnetic powder, metal
Oxide, metal carbonate, metal sulfate, metal nitride, metal charcoal
As appropriate from inorganic compounds such as fluorides and metal sulfides.
Is possible. Above all, small particle size distribution and functional addition
Because there are many means, such as titanium dioxide, zinc oxide,
Iron oxide and barium sulfate are preferred, titanium dioxide, α-
Iron oxide is more preferred. The average particle size of these nonmagnetic powders
Izu is preferably in the range of 0.005 to 2 μm, but necessary
Depending on the combination of non-magnetic powders with different particle sizes
Even with a single non-magnetic powder,
Can have an effect. [Binder] Magnetic layer and lower layer of magnetic recording medium
Conventionally known types and amounts of binders used in the layer
Technology is available. As the binder, conventionally known thermoplastics
Resins, thermosetting resins, reactive resins and mixtures of these
used. The thermoplastic resin has a glass transition temperature of
−100 to 150 ° C., number average molecular weight of 1000 to 200
000, preferably 10,000 to 100,000, degree of polymerization
Of about 50 to 1000 is used. Specifically
Is vinyl chloride, vinyl acetate, vinyl alcohol, male
Acid, acrylic acid, acrylic ester, vinylidene chloride
, Acrylonitrile, methacrylic acid, methacrylic acid
Stealth, ethylene, styrene, butadiene, vinyl buty
Single amount of lar, vinyl acetal, vinyl ether, etc.
Polymers and copolymers containing structural units derived from the body
Examples include urethane resin and various rubber resins.
The Also, as thermosetting resin and reactive resin
Phenolic resin, epoxy resin, polyurethane cured
Mold resin, urea resin, melamine resin, alkyd resin, active resin
Ryl reaction resin, formaldehyde resin, silicone resin
Fat, epoxy-polyamide resin, polyester resin and
Mixture of socyanate prepolymer, polyester poly
A mixture of all and polyisocyanate, polyurethane and
And mixtures of polyisocyanates.
The The above resins may be used alone or in appropriate combination.
But it is preferable to use vinyl chloride.
Nyl resin, vinyl chloride-vinyl acetate copolymer, vinyl chloride
Ru-vinyl acetate-vinyl alcohol copolymer, vinyl chloride
Selected from ru-vinyl acetate-maleic anhydride copolymer
A combination of at least one and a polyurethane resin, or
These include a combination of polyisocyanates.
It is. These binders have better dispersibility and durability
-COOM, -SO as necessary to obtain _Three M, -O
SO _Three M, -P = O (OM) ₂ , -OP = O (OM) ₂ ,-
OH, -NR ₂ , -N ⁺ R _Three , Epoxy group, -SH, -C
Co-load at least one polar group selected from N, etc.
It is preferable to use those introduced by the addition or addition reaction.
(In the characteristic group, M is a hydrogen atom or an alkali metal
A base, and R represents a hydrocarbon group). like this
The amount of characteristic groups is 10 ^-1 -10 ^-8 In the range of mol / g.
And preferably 10 ^-2 -10 ^-6 In the range of mol / g.
Are more preferable. Used for lower layer and magnetic layer of magnetic recording medium
The binder is non-magnetic powder in the lower layer and in the magnetic layer.
Is in the range of 5 to 50% by weight with respect to the ferromagnetic metal powder.
And preferably in the range of 10 to 30% by weight. A magnetic recording medium basically includes the above-described magnetic layer.
It consists of a lower layer, but at least one of the lower layer and the magnetic layer
Multiple layers may be used. Again, the final surface fineness of the coating layer
The pore volume is in the range of 0.03 to 0.3 ml / g
If you adjust the type and amount of carbon black and abrasive
Good. Also, the amount of binder, vinyl chloride occupying in the binder
Resin, polyurethane resin, polyisocyanate, or
Is the amount of the other resin, the molecule of each resin that forms the magnetic layer
Quantity, polar group quantity, or physical properties of the resin mentioned above
Of course, it is possible to change for each layer as needed
Rather, it should be optimized at each layer,
Any known technique can be used. For example, in each layer
To reduce the scratches on the surface of the magnetic layer when changing the amount of the mixture
To increase the amount of binder in the magnetic layer,
To improve head touch, increase the amount of binder in the lower layer.
Can be flexible, but can be applied
In doing so, it is optimized within the range where the effect of the present invention is exhibited.
It is preferable. In at least one of the lower layer and the magnetic layer,
Each layer can be cured by adding polyisocyanate
It is preferable for improving the durability. Specifically, Toray
Diisocyanate, 4,4'-diphenylmethane dii
Socyanate, hexamethylene diisocyanate, xy
Lylene diisocyanate, naphthylene-1,5-diiso
Cyanate, o-toluidine diisocyanate, isophor
Long diisocyanate, triphenylmethane triisocyanate
Isocyanates such as anoates and these isocyanates
Products of anates and polyalcohols,
Polyisocyanates formed by condensation of anates
Etc. can be used. These alone or cured
Each in two or more combinations using the difference in responsiveness
It can also be used with layers. [Additives] For the magnetic layer and lower layer of the magnetic recording medium
In addition to the above-mentioned lubricant, lubrication effect, antistatic effect, dispersion
Add various additives with effects and plasticity
May be. Additives include silicone oil, polar group
Silicone, fatty acid-modified silicone, fluorine-containing
Silicone, fluorine-containing alcohol, fluorine-containing beauty treatment salon
, Polyolefin, polyglycol, alkyl phosphate
Esters and their alkali metal salts, alkyl sulfates
Tellurium and its alkali metal salts, polyphenyl ether
, Phenylphosphonic acid, α-naphthyl phosphoric acid, phenyl
Phosphoric acid, diphenyl phosphate, p-ethylbenzenephospho
Acid, phenylphosphinic acid, aminoquinones, various
Run coupling agent, titanium coupling agent, fluorine-containing
Alkyl sulfate esters and alkali metal salts thereof
Is mentioned. In addition, all or one of these additives
Is added at any stage of magnetic and non-magnetic coating production.
Also good. For example, when mixing with a magnetic body before the kneading step,
When adding in the kneading process with magnetic material, binder and organic solvent
When adding in the dispersion step, when adding after the dispersion,
In some cases, it is added just before coating. Depending on the purpose
After applying the magnetic layer, the additives can be applied simultaneously or sequentially.
The purpose is achieved by applying part or all of
There is a case. Depending on the purpose, calendar processing (calendar
After heat and pressure treatment with a render roll) or
After finishing, the lubricant can be applied to the surface of the magnetic layer.
The [Layer structure] The layer structure of the magnetic recording medium is described in more detail.
Explain. The thickness of the magnetic recording medium support is 2 to 1
Preferably in the range of 00 μm, 2-80 μm
A range is more preferable. Between the support and the lower layer
An undercoat layer for improving adhesion may be provided. Undercoat layer thickness
Is preferably in the range of 0.01 to 0.5 μm.
More preferably in the range of 0.02 to 0.5 μm.
That's right. The magnetic recording medium has a lower layer and a magnetic layer on both sides of the support.
Even a double-sided magnetic layer recording medium provided with a single layer
Alternatively, a recording medium provided with them may be used. The former place
In this case, the surface of the coating layer of the present invention includes a lower layer and a magnetic layer.
Means each side, i.e. both surfaces,
In the latter case, one side of the lower layer and the magnetic layer is provided.
Means surface. In addition, a lower layer and a magnetic layer are provided only on one side.
In the latter case, antistatic and curl correction etc.
In order to achieve the effect of
A gate layer may be provided. This thickness is 0.1-4 μm
Preferably in the range of 0.3 to 2.0 μm
It is more preferable that These primer layers, backco
A well-known layer can be used. The thickness of the magnetic layer of the magnetic recording medium is determined by the magnetic field used.
Saturation magnetization of head, head gap length, recording signal
It is optimized by the bandwidth. The thickness of this magnetic layer
Is preferably in the range of 0.01 to 0.5 μm.
More preferably 0.03 to 0.3 μm,
More preferably in the range of 0.03-0.10 μm
Yes. Separate the magnetic layer into two or more layers with different magnetic properties
It does not matter if a configuration related to a known multilayer magnetic layer is used.
Yes. The thickness of the lower layer is usually in the range of 0.2 to 5 μm.
Preferably in the range of 0.3 to 3 μm, more preferably 1
More preferably, it is in the range of ˜2.5 μm. In addition,
If the lower layer is substantially non-magnetic, it will be effective
For example, a small amount of magnetic
Even if a sex body is included, it is regarded as substantially the same configuration as the present invention.
I've already mentioned that you can. Specifically, for example
The residual magnetic flux density of the layer is 0.01 Tesla (100 Gauss) or more
Lower or coercive force is less than 7.96kA / m (100Oe)
Preferably, the residual magnetic flux density and resistance
It has no magnetic force. [Support] Used for the magnetic recording medium of the present invention.
Non-magnetic supports include polyethylene terephthalate, polyethylene
Liethylene naphthalate, polyimide, polyamide
Such as sulfoxide, polysulfone and polybenzoxazole
Known film. These supports are clear
Corridor corona discharge treatment, plasma treatment, easy adhesion treatment, heat treatment
It is also possible to perform processing, dust removal processing, or the like. [Method of manufacturing magnetic recording medium] Magnetic recording of the present invention
The method for producing the medium is to prepare the coating liquid for forming each layer.
Adjustment, application of coating solution to support, orientation treatment, drying, cooling,
Calendar processing, punching processing, post-curing, polishing processing, assembly
And the like. Manufacture magnetic and non-magnetic paints for magnetic recording media
The manufacturing process includes at least a kneading process, a dispersing process, and
From the mixing process provided as necessary before and after these processes
Become. Each process is divided into two or more stages.
Also good. Ferromagnetic powder, non-magnetic powder, binder,
-Bon black, abrasive, antistatic agent, lubricant, solvent
Add all ingredients at the beginning or middle of any process
It doesn't matter. Individual raw materials can be separated in two or more processes.
It may be added in portions. For example, polyurethane
Mixing process for kneading process, dispersion process, viscosity adjustment after dispersion
You may divide and add as much as possible. When kneading and dispersing magnetic paints and non-magnetic paints
In this case, various kneaders are used. For example, two rolls
Mill, three roll mill, ball mill, pebble mill, Toro
Mills, sand grinders, Segva
ri), attritors, high-speed impeller dispersers, high-speed scanners
Tone mill, high speed impact mill, disper, kneader, high
Use a high speed mixer, homogenizer, ultrasonic disperser, etc.
Can. The method of applying the coating solution is not particularly limited,
The above-mentioned formed by applying a coating solution for a nonmagnetic layer on a support
While the non-magnetic layer is in a wet state, coating for the magnetic layer on it
Apply liquid (ie wet-on-wet application),
Next, it is dried and then surface-treated.
Manufacturing a magnetic layer with a uniform and pinhole thickness
Prevents coating defects such as high yield and non-magnetic
Prevents peeling of magnetic layer by improving adhesion between magnetic layer and magnetic layer
Also preferred above. Wet-on-wet application method
If the coating layer of the non-magnetic layer coating solution is wet, the magnetic
The coating liquid for the magnetic layer is applied at the same time as the coating liquid for the non-magnetic layer.
Or sequential. As the surface molding process, a calendar process is used.
As a calendering roll, epoxy, poly
Heat resistant such as amide, polyamide, polyimide amide
A plastic roll is used. Calendar pressure strip
For example, the linear pressure is 50 to 500 kg / cm, preferably
100-400 kg / cm, temperature 20-130 ° C, preferred
Or the range of 40-120 degreeC can be mentioned. Preparation of the above coating solution, coating method, drying conditions
The calendering conditions are the maximum surface pore volume of the coating layer.
Finally adjust to the range of 0.03-0.3 ml / g
If it is possible, an arbitrary condition can be selected. Next, the present invention will be described in detail by way of examples and comparative examples.
The present invention will be described. In the examples, “parts” is indicated by “weight”.
Part ". Example 1 Paint for magnetic layer formation (magnetic coating)
) And non-magnetic underlayer coating material (non-magnetic coating material)
The following were prepared as fees. The following
The amount of each component shown in the table is the same for ferromagnetic metal powder and non-magnetic
It is the amount per 100 parts by weight of the powder. <Magnetic paint> Barium ferrite magnetic powder 100 parts (Average plate diameter: 30 nm, Hc: 2700 Oe (216 kA / m)) Vinyl chloride copolymer (MR110: manufactured by Nippon Zeon) 12 parts Polyurethane resin (UR8300: Toyobo) 3 parts α-alumina (HIT55: manufactured by Sumitomo Chemical Co.) 10 parts carbon black (# 50: manufactured by Asahi Carbon Co., Ltd.) 3 parts phenylphosphonic acid 3 parts isohexadecyl stearate (iHDS) 3 parts stearic acid 2 parts methyl ethyl ketone 180 parts cyclohexanone 180 parts <Nonmagnetic paint> Nonmagnetic powder (α-Fe ₂ O _Three : Hematite) 100 parts Long axis length: 0.15 μm, specific surface area by BET method: 50 m ² / G, pH: 9, Surface treatment agent: Al ₂ O _Three (8% by weight), carbon black (# 3250B: manufactured by Mitsubishi Kasei) 18 parts vinyl chloride copolymer (MR104: manufactured by Nippon Zeon) 15 parts polyurethane resin (UR8300: manufactured by Toyobo) 7 parts phenylphosphonic acid 4 parts Isohexadecyl stearate (iHDS) 4.5 parts Oleic acid 1.3 parts Stearic acid 0.8 parts Methyl ethyl ketone / cyclohexanone (8/2 mixed solvent) 250 parts For each of the above two coating materials,
Knead the mixture with a kneader and disperse using a sand mill.
Let Polyisocyanate is added to the resulting dispersion, non-magnetic
Add 10 parts to the coating solution for the layer and 10 parts to the coating solution for the magnetic layer.
Furthermore, 40 parts of butyl acetate was added to each, and 1 μm
Filtered using a filter with an average pore size of
Prepare coating solutions for layer formation and magnetic layer formation respectively.
It was. The obtained non-magnetic layer coating solution was dried
To 1.5 μm, and immediately after that
In addition, the thickness after drying the magnetic layer coating solution will be 0.2μm
In other words, the thickness is 62 μm and the center line surface roughness is 0.01 μm.
Simultaneous multilayer coating on polyethylene terephthalate support
And the frequency 50H while both layers are still wet
z, magnetic field strength 0.025 Tesla, frequency 50 Hz,
Two magnetic field strengths of alternating current magnetic field with a magnetic field strength of 0.012 Tesla
Passed through the raw equipment, random orientation treatment, the best
After drying at a temperature of 100 ° C. and 5 hours after application, 7 steps of curry
The process is performed at a temperature of 90 ° C and a linear pressure of 300 kg / cm.
Punched to 3.7 inch diameter and surface polished
Thereafter, a center core was added to obtain a magnetic recording medium. (Example 2) Carbon black of magnetic paint
5 parts by weight, carbon black of non-magnetic paint 20
A sample was prepared in the same manner as in Example 1 except that the weight part was used.
did. Example 3 Carbon black of magnetic paint
Is made by Japan EC company Kechen Black EC, non-magnetic paint
Example, except that the carbon black of 22 parts by weight
A sample was prepared in the same manner as in Example 1. Comparative Example 1 Carbon Black of Magnetic Paint
Is replaced with the Canmax Co. Thermax MT.
Render processing conditions: temperature 100 ° C, linear pressure 300 kg / c
A sample was prepared in the same manner as in Example 1 except that m was used.
It was. (Comparative Example 2) Carbon black of magnetic paint
Was changed to KECENBLACK EC made by Japan EC Co., Ltd.
6 parts by weight, 22 layers of nonmagnetic paint carbon black
A sample was prepared in the same manner as in Example 1 except that the amount part was used.
It was. As in the above examples and comparative examples
Surface pore volume of various magnetic recording medium samples
The results of product, quality evaluation and durability evaluation are shown in Table 1. table
Measurement of surface pore volume, quality evaluation and durability evaluation in 1
Was carried out by the following method. (Measurement method of surface pore volume) Rice QUAN
Using TA CHROME measuring instrument Autosorb-1
And measured by the nitrogen adsorption method. Autosorb-1 is B
The pores are measured by the HJ method and the volume is measured. This
First, the magnetic recording medium is
After soaking in hexane, degas for 5 hours or more, under liquid nitrogen
The measurement was carried out with Autosorb-1. After measurement, magnetic recording
Remove the coating layer from the recording medium and degas the coating layer to reduce the weight.
It was measured. By dividing the total pore volume by this weight,
Thus, the total pore volume per coating layer weight was calculated. (Signal quality evaluation after 3000 continuous magnetic transfer operations)
Method) Pre-transformation using magnetic transfer master carrier
A mat signal is recorded by magnetic transfer. New display
Magnetic transfer is performed while changing to
Remove the magnetic disk from which the image was copied,
Mounted on the track, head gap 0.30um, track width
6.0um magnetic head (radius: 21.5mm, rotation
(Number: 3600 rpm)
The magnetic transfer characteristics were evaluated based on the signal. 1 round of disk
Observe the minute envelope with an oscilloscope
From the value (Emax) and the minimum value (Emin), Emin /
Emax × 100% is calculated and evaluated as magnetic transfer signal quality
I was worth it. If this value is 90% or more, good quality
Can be evaluated. (Durability in cycle environment) Floppy
(Registered trademark) disk drive (ZIP100 manufactured by Iomega, USA)
Rotational speed: 2968 rpm) and a radius of 38 mm
The head is fixed in place and recording is performed at a recording density of 34 kfci.
After that, the signal was reproduced to be 100%. As shown in FIG.
Thermocycle with one cycle cycle
The car was run for 120 hours in a car environment. Monitor the output and
Durability test when the output value of 70% or less of the initial value
The study was finished. [Table 1] According to Table 1 above, Examples 1-3 were
The surface pore volume of the coating layer is 0.03 to 0.3 ml / g
Because it is within the range, it runs for 120 hours in a thermocycle environment.
No error occurs even when the
High durability and signal after 3000 times of magnetic transfer
Since all the quality is over 90%, magnetic recording media
Transfer of lubricant from the magnetic transfer master carrier to
It is judged that it was controlled. In contrast, Comparative Example 1 has a surface pore volume.
Is an example of a small value of 0.008 ml / g.
In this case, the durability of the magnetic recording medium was good, but the master
The lubricant retained in the coating layer transferred to the body
Capillary phenomenon hardly occurred due to small pores and accumulated
Therefore, the signal quality evaluation after 3000 continuous magnetic transfer is low
It became a thing. Comparative Example 2 has a surface pore volume of 0.4 ml.
/ G is an example of a large case, but in this case the master
The lubricant retained in the coating layer transferred to the body is a capillary tube.
As a result of the phenomenon returning to the surface pores,
Accumulated lubricant can be suppressed and magnetic transfer continuous 3
Although the signal quality evaluation after 000 times was good, magnetic recording
Durability is reduced because the supply of lubricant to the media surface is reduced.
It became extremely bad. As described above, the flexible magnet of the present invention
The recording medium has a coating layer including a magnetic layer and a nonmagnetic layer.
The surface pore volume of the coating layer of flexible magnetic recording media
By setting it in the range of 0.03-0.3 ml / g,
Magnetic recording while retaining an appropriate amount of lubricant in the coating layer
A moderate amount of lubricant can be supplied to the surface of the medium.
Because it has improved the durability and scratch resistance of magnetic recording media
Became possible. In addition, flexible magnetic recording media
During copying, the lubricant transferred to the master carrier is applied to the surface of the coating layer.
Magnetic recording medium sucked by capillary action due to pores
Returning to the body, the transfer to the master carrier was suppressed.
The number of continuous transfer of air transfer can be made longer than before.
It was.

[Brief description of the drawings] FIG. 1 is a thermocycle flow chart used for evaluation of examples.

Claims (1)

What is claimed is: 1. A coating layer comprising a magnetic layer and a non-magnetic layer, onto which a magnetic transfer master carrier having a concavo-convex pattern corresponding to information to be transferred is closely attached to transfer the information. A flexible magnetic recording medium having a surface pore volume of the coating layer in a range of 0.03 to 0.3 ml / g.