JP2003132522A - Magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low cost magnetic recording medium in which the electromagnetic transducing characteristics are good even in a recording/reproducing system combined with an MR head, in which a C/N or a S/N at a high density recording region is greatly improved in particular, and in which the productivity is excellent. SOLUTION: In the magnetic recording medium constituted by forming a magnetic layer on a supporting body, the magnetic recording medium is characterized in that a flat coating layer having the thickness of 0.10-1 μm and the surface roughness of equal to or less than 5 nm in which the number of protrusions having the height of equal to or more than 20 nm measured by the atomic force microscope (AFM) are equal to or less than 20/900 μm<2> is provided on at least either side of the supporting body.

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to a magnetic recording medium.
In particular, the present invention relates to a support for a magnetic recording medium. [0002] In the field of magnetic disks, Co modification
2MB MF-2HD flexible disk using iron oxide
Are now standard on personal computers.
It was. Today, however, the amount of data handled is increasing rapidly.
However, its capacity is not enough,
It was desired to increase the capacity of the bull disk. Also in the field of magnetic tape, in recent years,
Computer, personal computer, work
With the spread of office computers such as stations
Record computer data as an external storage medium
Magnetic tape (so-called backup tape)
There has been a great deal of research. Magnetic sensors for such applications
For practical use of computers, especially small computers
In combination with the increase in information processing capacity,
In order to achieve miniaturization, there is a strong demand for improved recording capacity.
It is. Conventionally, magnetic recording media include iron oxide and Co modified.
Iron oxide, CrO₂, Ferromagnetic metal powder (MP), hexagonal system
A magnetic layer in which ferrite powder is dispersed in a binder is used as a nonmagnetic support.
What is coated on the holder is widely used. Among these,
Metal fine powder and hexagonal ferrite fine powder recorded at high density
It is known to have excellent characteristics. Disc place
Used ferromagnetic metal fine powder with excellent high-density recording characteristics.
10MB MF-2TD, 21 for large capacity disk
MB using MF-2SD or hexagonal ferrite
Capacity disk is 4MB MF-2ED, 21MB
There is phlotypal etc., but capacity and performance are sufficient
I could not say. For this situation, high-density recording characteristics
Many attempts have been made to improve this. For example, LS-
With high capacity of 100M-120M such as 120 and ZIP
High-density recording is realized, and surface recording density is 0.2G.
bit / inch²The above high density recording is being demanded.
In addition, the disk from the request to shorten the access time
There is a tendency that the number of rotations becomes higher. Such high density, high rotation or high transfer
For magnetic recording media, to maintain stable recording and playback
In order to achieve this, even more advanced running performance and durability than conventional media
Is required. Hereinafter, recording on a coating type magnetic recording medium
Suggested destination mainly to improve density and running durability
Describe line technology. For example, in JP-A-6-52541
The average protrusion height of the abrasive on the surface of the magnetic layer is 15 nm or less
The magnetic tape is disclosed, and the head is worn and dirty.
A statement to improve and achieve both electromagnetic conversion characteristics and durability
There is. JP-A-6-12651 discloses Ra of a magnetic layer.
Is 15 nm or less, and protrusions of 30 nm or more are 125,000
0 to 250,000 / mm²Distributed magnetic layer
Disclosed a magnetic disk showing the amount of lubricant in the magnetic layer.
ing. JP-A-6-309650 discloses lubrication.
Containing 8-30 parts by mass of magnetic agent to 100 parts by mass of magnetic powder
The number of protrusions higher than 20 nm lower surface from the highest protrusion of the layer
400 ~ 2,500 / mm²Magnetic recording medium, ie magnetic layer
Lubricant amount and density of protrusions with specific height on magnetic layer surface
By trying to ensure driving stability
A magnetic recording medium, particularly a magnetic disk, is disclosed. Conventionally, electromagnetic induction has been used as the operating principle.
Magnetic heads (inductive magnetic heads) are widely used
Yes. However, it is limited for use in higher density recording / playback areas.
Is starting to appear. That is, to obtain a large playback output
In order to achieve this, it is necessary to increase the number of coil turns of the reproducing head.
Inductance increases and resistance at high frequencies increases.
As a result, there is a problem that the reproduction output decreases. In recent years, MR (magnetoresistance) has been used as the operating principle.
A raw head was proposed and started to be used on hard disks.
In addition, JP-A-8-227517 discloses a magnetic tape.
Application to the network has been proposed. MR head is inductive magnetic
A playback output several times that of the head is obtained, and
Equipment noise such as impedance noise.
Noise is greatly reduced, and noise of magnetic recording media can be reduced.
It has become possible to obtain a large S / N ratio. In other words
Magnetic recording medium noise that was hidden behind conventional equipment noise
Can be recorded and played back well, and high-density recording characteristics.
Can be dramatically improved. However, the MR head is affected by minute heat.
The problem of generating noise (thermal noise)
Yes, especially when it hits a protrusion on the surface of the magnetic layer
The problem of sudden and persistent noise increase
Yes, so that error correction is impossible in digital recording
May cause problems. This thermal noise problem
Has a recording density of 0.5 Gbit / inch²Repeat the above recording signal.
Serious in magnetic recording media used in live systems
Become. To reduce such thermal noise, magnetic
It is important to control the surface properties of the layer
It has been done to control the surface properties of the support as a step
Yes. For example, Japanese Patent Nos. 2938548 and 2nd
No. 935549 discloses a polyurethane coating on a support.
The one provided with a layer is disclosed in Japanese Patent Publication No. 5-57647,
A layer made of a compound that polymerizes upon irradiation on a support
It is proposed that provided. However, the former prior art
Are expensive to manufacture and have poor smoothness.
The latter requires expensive radiation irradiation equipment
And may damage the support during coating.
There was a problem such as. [0011] The present invention provides an MR head.
Electromagnetic conversion characteristics in combined recording and playback systems
C / N or S / N in a high-density recording area is good.
Remarkably improved magnetic recording medium with excellent productivity and low price
The purpose is to provide a body. [0012] The present invention provides a magnet on a support.
In a magnetic recording medium formed with a conductive layer, the support
A thickness of 0.10 to 1 μm on at least one surface of
With a surface roughness of 5 nm and an atomic force microscope (AFM)
20 protrusions with a height of 20 nm or more measured / 900
μm²The following smooth coating layer is provided.
This is a magnetic recording medium. A preferred embodiment of the present invention is
It is as follows. (1) Methyl ethyl ketone (MEK) of the smooth coating layer
/ Elution amount to cyclohexanone mixed solution (1: 1)
0.0-0.4mg / cm²The magnetic recording medium. (2) The smooth coating layer has a number average molecular weight of 10,000 to 1
The magnetic recording medium comprising 00000 polymer. (3) The viscosity of the coating solution for forming the smooth coating layer is 50c.
p or less and the surface tension is 22 mN / m or more.
Care recording medium. (4) The smooth coating layer has a radiation curable functional group in the molecule.
After applying the coating solution containing the compound
The magnetic recording medium formed by spray curing. (5) The magnetic layer mainly comprises a ferromagnetic powder and a binder,
The magnetic recording medium having a thickness of 20 to 500 nm. (6) A nonmagnetic powder is bonded between the magnetic layer and the smooth coating layer.
A non-magnetic layer having a thickness of 0.5 to 3.0 μm including the mixture was provided.
The magnetic recording medium. (7) Wet-on-wet coating of the nonmagnetic layer and the magnetic layer
The magnetic recording medium provided by a cloth. [0013] The magnetic recording medium of the present invention comprises a support.
0.10 to 1 μm in thickness on at least one surface of
Surface roughness is less than 5nm and by atomic force microscope (AFM)
Protrusions with a height of 20 nm or more (hereinafter referred to as “PN”)
(Also referred to as “20 nm or more”)) / 20 μm / 900 μm²
The following smooth coating layer is provided. smooth
Even if the coating layer is provided on both sides of the support, it is only provided on one side.
It may be. For example, in the case of a disk-shaped magnetic recording medium
Usually, a smooth coating layer is provided on both sides, and tape-like magnetic
In the case of a recording medium, it is usually provided on one side.
Not determined. The thickness of the smooth coating layer is 0.20 to 0.70
More preferable is μm. The thickness of the smooth coating layer is outside the above range
Surface roughness of smooth coating layer and PN (20nm or more)
Tends to be difficult to adjust to the scope of the present invention.
If the thickness exceeds 1 μm, tape-shaped magnetic recording
This is disadvantageous for increasing the capacity of the medium. Surface of smooth coating layer
Roughness is 250μm square with WYKO TOPO-3D.
The measured center plane average surface roughness Ra is shown. Ra is 0.5
To 4.0 nm is more preferable, and 1.0 to 3.0 nm is particularly preferable.
Is preferred. The height of the protrusion on the smooth coating layer is the original height.
The center plane (with a flat surface and a rough curved surface)
Enclosed volume is equal and minimal above and below the plane
This is defined as the height with respect to the plane. Therefore, PN
(20 nm or more) means that the height above this reference plane is 20 n
The total number of protrusions that are more than m per 30 μm square is the protrusion density.
Show. PN (20nm or more) is 10 pieces / 900μm²Less than
More preferred is below. Ra and PN of smooth coating layer (20n
m or more) is preferably as small as possible.
If at least one exceeds the above range, C / N or S / N will be improved.
Not good. Forming a smooth coating layer as described above on a support
There are no particular restrictions on the means to do this, but the following means are preferred.
Good. 1) Smooth coating layer by applying and drying polymer solution on support
Means to form. 2) Compound having radiation curing functional group in the molecule on the support
After applying the coating solution containing the product, it is cured by irradiation with radiation.
Means for forming a smooth coating layer. First, means 1) will be described. Polymer solution used
Is preferably 50 cp or less, and more preferably 3
0 cp or less is preferable. The surface tension of the coating solution is 22
mN / m or more is preferable, and 24 mN / m or less is more preferable.
That's right. As a polymer, the number average molecular weight is 10,000-1
00000 is preferred. Also, apply a coating layer on the smooth coating layer
When the magnetic recording medium is provided, the coating layer solution is used.
Polymers that are insoluble or sparingly soluble in the medium are preferred, especially water-soluble
Polymers are preferred. Also, the glass transition temperature (T
g) is preferably 0 ° C to 120 ° C, more preferably 1
0 degreeC-80 degreeC is preferable. If it is less than 0 ° C,
King may occur, and if it exceeds 120 ° C, smooth coating
The internal stress in the fabric layer is not relieved, and as a result, adhesion is ensured
There are cases where it is not possible. The polymer to be used is not particularly limited.
Are preferably those satisfying the above conditions, polyamide,
Polyamideimide, polyester, polyurethane, acrylic
Examples include ril-based resins. As polyamide, dia
Ring opening of lactams, a polycondensation compound of min and dicarboxylic acid
Polymer compound, 1/1 of diamine and dicarboxylic acid (mol
Ratio) salts and copolymers of lactams such as caprolactam
Etc. Examples of diamines include hydrazine and methylene.
Diamine, ethylenediamine, trimethylenediamine,
Tetramethylenediamine, pentamethylenediamine, f
Xamethylenediamine, heptamethylenediamine, oct
Tamethylenediamine, Nonamethylenediamine, Decamechi
Range amine, diaminocyclohexane, di (amino
Til) cyclohexane, bis- (4-aminocyclohex)
Syl) methane, bis- (4-amino-3,5-methylsilane)
Chlohexyl) methane, o-phenylenediamine, m-
Phenylenediamine, p-phenylenediamine, 4,
4'-diaminobiphenyl, tolylenediamine, xyle
Diamine, naphthylenediamine, bis (aminomethyl)
B) Piperazine, Bis (aminoethyl) piperazine, Bi
(Aminopropyl) piperazine, 1- (2-aminometh)
Chill) piperazine, 1- (2-aminoethyl) piperazi
1- (2-aminopropyl) piperazine, etc.
Yes. Dicarboxylic acids include oxalic acid and malon
Acid, succinic acid, glutaric acid, adipic acid, pimelin
Acid, azelaic acid, sebacic acid, cyclohexane dicar
Boric acid, orthophthalic acid, isophthalic acid, terephthalic acid
Acid, naphthalene dicarboxylic acid, etc. and their acid anhydrides
Can be used. As lactams, α-pyro
Lidon, α-piperidone, γ-butyrolactam, δ-ba
Lerolactam, ε-caprolactam, ω-capryllac
Tom, ω-laurolactam and the like are used. As the polyamide, amino acid polymerization
The body is mentioned. Amino acid polymers are not natural
However, it may be a polymer such as a protein such as collagen. Further
In addition, as a polyamide, plastic material course (1
6) “Polyamide resin” (Osamu Fukumoto, Nikkan Kogyo Shimbun)
Line); "Synthetic polymer V" (published by Asakura Shoten, Murahashi, Imoto,
(Tani); U.S. Pat. No. 2,130,497;
No. 3; No. 2149273; No. 2158064; No. 2
No. 223403; No. 2249627; No. 253434
7; 2540352; 2715620; 275
No. 6221; No. 2939862; No. 2999493
No .: No. 3012994; No. 3133756; No. 31
No. 88228; No. 3193475; No. 3193484
No. 3197443; No. 3226362; No. 32
No. 42134; No. 3247167; No. 329909
No .; No. 3328352; No. 3354123, etc.
In Japanese Patent Laid-Open No. 11-283241
From the described polyamides having tertiary amino groups
Can be appropriately selected and used. Polyamideimide has an amino group at the end.
Low molecular weight polyamides having acid groups and acid dianhydrides and their
Method by reaction with steal, low with amino group at the end
By reaction of polyamic acid of molecular weight with dibasic acid chloride
By the reaction of trimellitic acid derivative and diamine
Obtained by a method or the like. As the polyamide component, the above polyamide
Diamines and dicarboxylic acids or amino acids described in 1.
Are formed. Trimellitic acid induction
As the diamine used in the reaction with the body, etc.
Can be mentioned. As acid dianhydride and its ester,
Pyromellitic acid-1,4-dimethyl ester, pyromelli
Tetrate tetramethyl ester, pyromellitic acid ethyl ester
Stealth, 2,3,6,7-naphthalene tetracarboxylic acid
Dianhydride, 3,3 ′, 4,4′-biphenyltetracarbo
Acid dianhydride, 1,2,5,6-naphthalene tetracar
Boronic acid dianhydride, 2,2 ', 3,3'-biphenyltetra
Carboxylic dianhydride, 2,2 ', 6,6'-biphenylte
Examples include tracarboxylic dianhydride. Amino at the end
The low molecular weight polyamic acid having a group includes
By reacting with dianhydrides and their esters
Yes. As the dibasic acid chloride, the dicarboxylic acid
Chloride. Used polyamideimide and
"Polyamide resin handbook" (Nikkan Kogyo Shin
Can be appropriately selected from those described in
The Polyesters include dicarboxylic acids and groups.
Those synthesized from recall are mentioned. Dicarboxylic
Examples of acids include aromatic, aliphatic, and alicyclic ones.
Specific examples include the same as above, but
Aromatic ones are preferred. As the glycol component,
Lenglycol, diethylene glycol, triethylene
Glycol, tetraethylene glycol, propylene glycol
Recall, butanediol, neopentyl glycol,
Hexanediol, cyclohexanediol, cyclohexane
Aliphatics such as xanthanimethanol and bisphenol A,
Examples include alicyclic and aromatic glycols. Polyurethanes include polyols and dii
Manufactured by known methods from socyanate, chain extender, etc.
Things. Polyol is polyester
Polyol, polyether polyol, polycarbonate
Topolyol and the like are used. Polyester polyol
The polyester component of the polyester
For example. Diisocyanate includes magnetic layer
And those described in the binder used for
The Chain extenders include polyhydric alcohols and polyamines
(For example, the above-mentioned diamine etc.) etc. are used. Polymer used for forming the above smooth coating layer
-COOM, -SO if necessary_ThreeM, -OSO
_ThreeM, -P = O (OM)₂, -OP = O (OM)₂,
(M is hydrogen atom, alkali metal, or
Represents onium), OH, NR₂, N⁺R_Three(R is carbonized
Hydrogen group), epoxy group, SH, CN, etc.
Copolymerization or addition reaction of at least one polar group
It is preferable to use those introduced in (1). Such poles
The amount of the sex group is appropriately selected from 0.1 to 3 meq / g.
Are preferred. As the solvent for the coating solution for the smooth coating layer,
Acetone, methyl ethyl ketone, methyl isobutyl keto
, Diisobutyl ketone, cyclohexanone, isophor
Ketones such as ethylene and tetrahydrofuran, methanol,
Ethanol, propanol, butanol, isobutyl alcohol
Alcohol, isopropyl alcohol, methylcyclohex
Alcohols such as sanol, methyl acetate, butyrate
, Isobutyl acetate, isopropyl acetate, ethyl lactate,
Esters such as glycol acetate, glycol dimethyl ester
Ether, glycol monoethyl ether, dioxane,
Glycol ethers such as benzene, toluene,
Aromatic charcoal such as silene, cresol, chlorobenzene
Hydrides, methylene chloride, ethylene chloride,
Carbon tetrachloride, chloroform, ethylene chlorohydrin,
Chlorinated hydrocarbons such as dichlorobenzene, N, N-di
Methylformamide, hexane, water, etc. can be used
The These solvents are not necessarily 100% pure,
In addition to min, isomers, unreacted materials, side reactions, decomposition products, oxidation
It does not matter if impurities such as things and moisture are included. these
The impurity content is preferably 30% or less, more preferably 1
0% or less. Among these solvents, methanol, ethanol
Alcohols such as ethanol and isopropyl alcohol,
Water, cyclohexanone, methyl ethyl ketone, butyric acetate
Are preferably used alone or in combination. Next, means 2), ie radiation curing in the molecule
Smooth coating using a coating solution containing a compound having a functional group
The means for forming the fabric layer will be described. Molecule used
A compound having a radiation curing functional group (hereinafter referred to as `` radiation
(Also referred to as `` curable compounds '') radiation, e.g. electrons
When energy is given by lines, ultraviolet rays, etc.
A compound that has the property of being cross-linked, polymerized and cured
say. And radiation curable compounds are those energy
The reaction does not proceed unless ghee is given. Therefore radiation hard
Coating solutions containing chemical compounds are viscous unless irradiated with radiation.
The degree of stability is high and high coating smoothness can be obtained.
The In addition, the high energy from radiation instantly counters
Since the response proceeds, a high coating strength can be obtained. the above
The molecular weight of the radiation curable compound ranges from 200 to 2000.
It is preferable that it is a surrounding. When the molecular weight is in the above range,
Since it has a relatively low molecular weight, it is applied in the calendar process.
The film is easy to flow, has high moldability, and realizes a smooth coating film.
You can. As a bifunctional or higher radiation curable compound
Acrylic esters, acrylamides,
Rylic acid esters, methacrylic acid amides, allyl compounds
Products, vinyl ethers, vinyl esters, etc.
You can. As a specific example of a bifunctional radiation-curable compound
Ethylene glycol diacrylate, propylene
Glycol diacrylate, butanediol diacrylate
, Hexanediol diacrylate, diethylene glycol
Recall diacrylate, triethylene glycol dia
Chlorate, tetraethylene glycol diacryl
, Neopentyl glycol diacrylate, tripro
Pyrene glycol diacrylate, ethylene glycol
Dimethacrylate, propylene glycol dimethacrylate
, Butanediol dimethacrylate, hexanedio
Dimethacrylate, diethylene glycol dimethac
Relate, triethylene glycol dimethacrylate,
Tetraethylene glycol dimethacrylate, neopen
Tyl glycol dimethacrylate, tripropylene glycol
Aliphatic diols typified by cold dimethacrylate
Using acrylic acid or methacrylic acid added to
be able to. Polyethylene glycol, poly
Lopylene glycol, polytetramethylene glycol, etc.
Polyether polyol, acrylic acid, methacrylic
Polyether acrylate with added acid, polyether
Obtained from methacrylate, known dibasic acid or glycol
Acrylic acid, methacrylate
Polyester acrylate and polyester added with phosphoric acid
Termethacrylate can also be used. Known poly
Poly, which is a reaction of all-or-diol and polyisocyanate
Polyurethane with acrylic acid and methacrylic acid added to urethane
Riethane acrylate, polyurethane methacrylate
May be used. Bisphenol A, bisphenol
F, hydrogenated bisphenol A, hydrogenated bisphenol F
And these alkylene oxide adducts with acrylic acid,
Methacrylic acid added or isocyanuric acid
Xylene oxide modified diacrylate, isocyanuric acid
Alkylene oxide modified dimethacrylate, trisic
Rhodecane dimethanol diacrylate, tricyclodeca
Has a cyclic structure such as dimethylethanol dimethacrylate
Things can also be used. As a specific example of a trifunctional radiation curable compound
Trimethylol propane triacrylate, tri
Methylolethane triacrylate, trimethylol group
Lopane alkylene oxide modified triacrylate,
Pentaerythritol triacrylate, dipentaeri
Thritol triacrylate, isocyanuric acid alkyle
Oxide modified triacrylate, propionate dipe
Intererythritol triacrylate, hydroxypiva
Lualdehyde-modified dimethylolpropane triacrelate
Trimethylolpropane trimethacrylate, tri
Alkylene oxide modified trimer of methylolpropane
Tacrylate, pentaerythritol trimetacrine
Dipentaerythritol trimethacrylate, iso
Cyanuric acid alkylene oxide modified trimetacrine
Dipentaerythritol trimethacrylate, propionate
Rate, hydroxypivalaldehyde modified dimethylol
Propane trimethacrylate and the like can be used. Specific examples of tetrafunctional or higher radiation curable compounds
As pentaerythritol tetraacrylate,
Ditrimethylolpropane tetraacrylate, dipen
Taerythritol pentaacrylate, dipropionic acid
Pentaerythritol tetraacrylate, dipentae
Lithritol hexaacrylate, phosphazene
Use ruxylene oxide modified hexaacrylate etc.
be able to. Of these, preferred examples are
A bifunctional acrylate compound with a molecular weight of 200-2000
More preferred are bisphenol A, bisphenol
Nord F, hydrogenated bisphenol A, hydrogenated bisphenol
Acrylic F and these alkylene oxide adducts
It is a product to which phosphoric acid or methacrylic acid is added. Radiation curable compound used in the present invention
May be used in combination with a polymer-type binder. Used together
As the binder, a polymer of the above means 1) or a conventionally known heat is used.
Plastic resin, thermosetting resin, reactive resin and mixtures of these
Things are used. When using ultraviolet rays as radiation
It is preferable to use a polymerization initiator in combination. Polymerization initiator
As photo radical polymerization initiator, photo cationic polymerization start
An agent, a photoamine generator, and the like can be used. Examples of the photo radical polymerization agent include:
Α-diketones such as benzyl and diacetyl, benzoin, etc.
Of acyloin, benzoin methyl ether, benzoy
Ethyl ether, benzoin isopropyl ether, etc.
Acyloin ethers, thioxanthone, 2,4-di
Ethylthioxanthone, thioxanthone-4-sulfone
Thioxanthones such as acids, benzophenone, 4,4'-bi
(Dimethylamino) benzophenone, 4,4'-bis
Benzophenones such as (diethylamino) benzophenone
, Michler's ketones, acetophenone, 2- (4-to
Ruensulfonyloxy) -2-phenylacetopheno
, P-dimethylaminoacetophenone, α, α'-di
Methoxyacetoxybenzophenone, 2,2'-dimethoxy
Si-2-phenylacetophenone, p-methoxyaceto
Phenone, 2-methyl [4- (methylthio) phenyl]
2-morpholino-1-propanone, 2-benzyl-
2-Dimethylamino-1- (4-morpholinopheny
Acetophenones such as l) -butan-1-one and ant
Quinones such as laquinone and 1,4-naphthoquinone, phena
Silk chloride, trihalomethylphenylsulfone,
Halogens such as lis (trihalomethyl) -s-triazine
Compounds, acylphosphine oxides, di-t-butyl
Examples include peroxides such as peroxides. Further, as a radical photopolymerization agent, for example, IR
GACURE-184, 261, 369, 500, 6
51, 907 (Ciba-Geigy), Darocur-1
173, 1116, 2959, 1664, 40
43 (Merck Japan), KAYACURE-DETX, MB
P, DMBI, EPA, OA (Nippon Kayaku Co., Ltd.), V
ICURE-10, 55 (manufactured by STAUFFER Co.LTD), TRIGONA
LP1 (manufactured by AKZO Co.LTD), SANDORAY 1000 (SANDOZ Co.
LTD), DEAP (APJOHN Co.LTD), QUANTACURE-PD
O, ITX, EPD (made by WARD BLEKINSOP Co.LTD), etc.
Commercial products can also be used. As the cationic photopolymerization initiator, dia
Zonium salts, triphenylsulfonium salts, metallo
Cene compounds, diaryliodonium salts, nitrobe
Benzyl sulphonates, α-sulphonyloxy ketones,
Diphenyl disulfones and imidyl sulfonates
I can get lost. Adekault as a photocationic polymerization initiator
Lasset PP-33, OPTMER SP-150
170 (Asahi Denka Kogyo Co., Ltd.) (diazonium salt),
OPTOMER SP-150, 170 (Asahi Denka Kogyo)
(Supplied) (sulfonium salt), IRGACURE 2
61 (Ciba-Geigy) (metallocene compound)
Commercial products such as these can also be used. As the photoamine generator, nitrobenzica is used.
-Bamimates and iminosulfonates.
These photopolymerization initiators are used under exposure conditions (for example, oxygen atmosphere).
Whether it is under the air or under an oxygen-free atmosphere)
It is appropriately selected and used. These photopolymerization initiators are
Two or more kinds can be used in combination. Radiation curable compounds or other bonds
A composition containing an agent and a photopolymerization initiator
The solvent is used as a coating solution. As the solvent, means 1)
It selects suitably from what was illustrated by (1). Apply the above coating on the support.
After applying the cloth fluid, radiation is usually applied to the coating layer after drying.
Be shot. Drying can be either natural drying or heat drying
Yes. When an electron beam is used as radiation, the total electron dose is
1-20 Mrad is preferred in amount, 3-10 Mrad is
Further preferred. When using ultraviolet rays as radiation,
The amount is 10-100mJ / cm²Is preferred. UV
(UV) and electron beam (EB) irradiation equipment, irradiation conditions, etc.
For details, refer to “UV / EB Curing Technology” (General Technology Center Co., Ltd.).
Issue) and "Applied technology for low-energy electron beam irradiation"
(2000, issued by CMC Co., Ltd.)
The well-known thing can be used. Smooth coating layer
The thickness depends on the components of the smooth coating layer, etc.
preferable. In the case of magnetic tape, surface properties of smooth coating layer, physical properties
If reasoning is ensured, the thinner the better for higher capacity.
Good. The coating solution for the smooth coating layer contains a desired surface.
It is also possible to include a filler to obtain
The The maximum diameter of the filler is preferably 50 nm or less. 50
If it exceeds nm, it may cause dropout (DO)
There is a match. However, a set of coating solutions for such a smooth coating layer
To form a smooth coating layer outside the scope of the present invention.
Such as a back layer by applying such a coating solution to the other side of the support.
May be formed to form a tape-like magnetic recording medium. So
In the case of, further layer of other composition is formed on the smooth coating layer
May be. Further, the smooth coating layer may be a magnetic layer coating solution or a non-magnetic layer.
It is desired to be stable with respect to the coating liquid for the adhesive layer. Follow
Smooth coating layer of methyl ethyl ketone (MEK) /
Elution amount to rohexanone mixed solution (1: 1) is 0.0 ~
0.4 mg / cm²Is preferably 0.0 to
0.2mg / cm²More preferably. The magnetic layer provided in the present invention is a ferromagnetic powder.
And suitable for coating type mainly composed of binder, but ferromagnetic gold
It may be a genus thin film type. In the latter case, vapor deposition, spatter
The magnetic layer can be provided by a known method such as a method. Coating
In the case of a mold, the thickness of the magnetic layer is preferably 0.02 to 0.5 μm
Moreover, 0.05 to 0.2 μm is more preferable. Magnetic
The non-magnetic layer includes a non-magnetic powder and a binder on the smooth coating layer.
It is preferable to provide it on top of a sexual layer (also called the lower layer)
Yes. The thickness of the nonmagnetic layer is preferably 0.5 to 3.0 μm,
Furthermore, 0.8-2.0 micrometers is preferable. Also, the magnetic layer (top
Layer or upper magnetic layer) and nonmagnetic layers are nonmagnetic layers.
Wet-on-wet with a magnetic layer in the wet state
It is preferably provided by (W / W) coating. Smooth coating
When providing a non-magnetic layer or magnetic layer on the layer, apply a smooth coating layer.
The support to be supported is wound up after the smooth coating layer is formed.
It is preferable to provide a nonmagnetic layer, a magnetic layer, etc.
However, what is wound may be used. Hereinafter, the present invention is a coating type magnetic recording medium.
The case will be described for each component. [Magnetic layer] The magnetic recording medium of the present invention comprises a lower layer and an ultrathin magnetic layer.
May be provided on only one side of the support or on both sides. Upper and lower layers
After applying the lower layer, even if the lower layer is wet (W / W),
After the lower layer is dried, it is wet on dry (W / D)
Also, an upper magnetic layer can be provided. From the point of production yield
Simultaneous or sequential wet application is preferred.
Can be used after drying. At the same time in a multilayer structure, or
In sequential wet coating (W / W), the upper and lower layers can be formed simultaneously.
Effective surface treatment process such as calendar process
The surface roughness of the upper magnetic layer can be improved even with ultra-thin layers.
The The coercive force Hc of the magnetic layer is 160 kA / m or more.
Preferably, the ferromagnetic metal powder has a Bm of 0.2-0.
5T, 0.1 to 0.3T for hexagonal ferrite powder
It is preferable. [Ferromagnetic powder] Used in the magnetic layer of the present invention.
Ferromagnetic powder should not be restricted in particular
Is a ferromagnetic metal powder mainly composed of α-Fe, hexagonal crystals
Celite powder is preferred. These ferromagnetic metal powders
In addition to predetermined atoms, Al, Si, S, Sc, Ca, Ti,
V, Cr, Cu, Y, Mo, Rh, Pd, Ag, Sn,
Sb, Te, Ba, Ta, W, Re, Au, Hg, P
b, Bi, La, Ce, Pr, Nd, P, Co, Mn,
It may contain atoms such as Zn, Ni, Sr, B, etc.
Yes. In particular, Al, Si, Ca, Y, Ba, La, Nd,
Contains at least one of Co, Ni, and B in addition to α-Fe
Preferably, it contains at least one of Co, Y, and Al.
More preferably. Co content relative to Fe
0 atom% or more and 40 atom% or less is preferable and more preferable.
Or 15 atomic% to 35%, more preferably 20 raw materials.
The atomic percentage is not less than 35 atomic%. Y content is 1.5 raw
Preferably, the atomic percentage is not less than 12 atomic%, and more preferably
3 atom% or more and 10 atom% or less, more preferably 4 atom%
It is 9 atomic% or less. Al is 1.5 atomic% or more 12
Atomic% or less is preferable, more preferably 3 atomic% or more
10 atomic% or less, more preferably 4 atomic% or more and 9 atomic%
It is as follows. These ferromagnetic powders will be discussed later.
Before dispersion with powder, lubricant, surfactant, antistatic agent, etc.
Processing may be performed in advance. Specifically,
No. 44-14090, No. 45-18372,
JP-B 47-22206, JP-B 47-22513
, Shoko 46-28466, Shoko 46-3875
No. 5, No. 47-4286, No. 47-1242
No. 2, No. 47-17284, No. 47-185
09, JP 47-18573, JP 39-10
No. 307, Japanese Patent Publication No. 46-39639, US Patent No. 30
No. 26215, No. 3031341, No. 3100194
No., No. 3420005, No. 3338914, etc.
It is listed. The ferromagnetic powder contains a small amount of hydroxide or acid.
Chemicals may be included. Ferromagnetic metal powder is a known manufacturing method
Can be obtained by the following method:
Can be mentioned. Complex organic acid salt (mainly Shu
Acid) and a reducing gas such as hydrogen, iron oxide
Is reduced with a reducing gas such as hydrogen to obtain Fe or Fe-
A method for obtaining Co particles, etc.
Solution, a solution of ferromagnetic borohydride in aqueous solution of ferromagnetic metal
Um, hypophosphite or hydrazine reducing agents
Addition and reduction, metal is steamed in a low-pressure inert gas
For example, a method of obtaining fine powder by emitting. In this way
The obtained ferromagnetic metal powder is a known slow oxidation treatment, that is,
Method of drying after soaking in organic solvent, soaking in organic solvent
After soaking, oxygen-containing gas is sent to form an oxide film on the surface
After drying, oxygen gas without using organic solvent
And adjust the partial pressure of inert gas to form an oxide film on the surface
Any of these methods can be used. The ferromagnetic metal powder of the magnetic layer of the present invention is changed to BET.
Specific surface area (S_BET) 45 to 80m²/
g is preferred, more preferably 50 to 70 m.²/ G
The 45m²If it is less than / g, the noise becomes high and 80 m²
When it exceeds / g, it is difficult to obtain surface properties, which is not preferable. The present invention
The crystallite size of the ferromagnetic metal powder of the magnetic layer is 80-18.
0cm is preferred, more preferably 100 to 180cm, especially
It is preferably 110 to 175 mm. Ferromagnetic metal powder
The long axis length is preferably 0.01μm or more and 0.15μm or less.
More preferably 0.03 μm to 0.15 μm
And particularly preferably 0.03 μm or more and 0.12 μm
It is as follows. The needle ratio of the ferromagnetic metal powder is 3 or more and 15 or less.
And more preferably 5 or more and 12 or less. Ferromagnetic
Saturation magnetization σs of the conductive metal powder is 100 to 180 A · m²/
kg, preferably 110 to 170 A · m²/ K
g, more preferably 125 to 160 A · m²/ Kg
The The coercive force of the ferromagnetic metal powder is 160 to 280 kA / m
Is preferable, and more preferably at 176 to 240 kA / m.
is there. The moisture content of the ferromagnetic metal powder is 0.01-2%.
Is preferable. Ferromagnetic metal depending on the type of binder
It is preferable to optimize the moisture content of the powder. Ferromagnetic metal powder
The pH of the powder is optimized by the combination with the binder used
It is preferable. Its range is 4-12, but is preferred
Or 6-10. Ferromagnetic metal powder is A
Surface treatment with l, Si, P or oxides of these
It doesn't matter. The amount is 0. 0 with respect to the ferromagnetic metal powder.
1 to 10% and surface treatment, lubricant such as fatty acid
Adsorption of 100 mg / m²The following is preferable. Ferromagnetic
Metal powders are soluble Na, Ca, Fe, Ni, Sr
Any inorganic ion may be included. These are essentially
It is preferable not to have it, but if it is 200 ppm or less, it is especially characteristic
It has little effect on Also used in the present invention
It is preferable that the ferromagnetic metal powder has fewer holes.
Is 20% by volume or less, more preferably 5% by volume or less.
The For the shape, the particle size shown above
Any of needle shape, rice grain shape and spindle shape
It doesn't matter. The smaller the SFD of the ferromagnetic metal powder itself
Preferably, 0.8 or less is preferable. H of ferromagnetic metal powder
It is necessary to reduce the distribution of c. SFD is 0.8.
If the following, the electromagnetic conversion characteristics are good, the output is high, and
In addition, the magnetization reversal is sharp and the peak shift is reduced,
Suitable for high density digital magnetic recording. Small distribution of Hc
In order to avoid this, the ferromagnetic metal powder is
To improve the particle size distribution of the toner and prevent sintering
is there. Next, the hexagonal ferrite powder is described.
The As hexagonal ferrite used in the present invention, barium
Ferrite, strontium ferrite, lead ferrite
, Calcium ferrite substitutes, Co substitutes, etc.
is there. Specifically, magnetoplumbite-type barium
Granite with Celite and Strontium Ferrite, Spinel
Magnetoplumbite type ferrite coated on the child surface,
In addition, magnetoplumbite type partially containing spinel phase
Barium ferrite and strontium ferrite, etc.
In addition to predetermined atoms, Al, Si, S,
Sc, Ti, V, Cr, Cu, Y, Mo, Rh, Pd,
Ag, Sn, Sb, Te, Ba, Ta, W, Re, A
u, Hg, Pb, Bi, La, Ce, Pr, Nd, P,
Co, Mn, Zn, Ni, Sr, B, Ge, Nb, etc.
It may contain atoms. Generally Co-Zn, Co
-Ti, Co-Ti-Zr, Co-Ti-Zn, Ni-
Ti-Zn, Nb-Zn-Co, Sb-Zn-Co, N
Can be added with elements such as b-Zn
The Contains specific impurities depending on the raw material and manufacturing method
There is also. The particle size is usually a hexagonal plate diameter of 10 to 10.
0 nm, preferably 10 to 60 nm, particularly preferably
10-50 nm. Especially to increase the track density M
When playing with the R head, it is necessary to reduce the noise.
The plate diameter is preferably 40 nm or less.
Stable magnetization cannot be expected due to fluctuations. Over 100nm
And high noise, both of which are not suitable for high-density magnetic recording
Yes. The plate ratio (plate diameter / plate thickness) is preferably 1-15. Like
It is 1-7. When the plate ratio is small, the magnetic layer is filled
However, sufficient orientation cannot be obtained.
If it is greater than 15, noise will occur due to stacking between particles.
growing. Ratio table of this particle size range by BET method
The area is 10-100m²/ G. Specific surface area is roughly grain
This is an arithmetic value calculated from the daughter plate diameter and thickness. Particle plate diameter
The narrower the plate thickness distribution, the better. Quantification is particle TE
Can be compared by randomly measuring 500 particles from M photos
The In many cases, the distribution is not a normal distribution.
In terms of standard deviation relative to average size, σ / average size =
0.1-2.0. Sharpen particle size distribution
To make the particle generation reaction system as uniform as possible,
Distribution improvement processing is also performed on the generated particles.
The For example, selective dissolution of ultrafine particles in acid solution
Methods are also known. Coercive force Hc measured with magnetic material
Can usually be made up to about 40 to 400 kA / m. H
A higher c is advantageous for high-density recording.
Limited by ability. In the present invention, the Hc of the magnetic material is 160 to
Although it is about 320 kA / m, Preferably it is 176-28
0 kA / m. Head saturation magnetization of 1.4 Tesla
If it exceeds, 176kA / m or more is preferable.
Yes. Hc is the particle size (plate diameter / plate thickness) and the type of element contained
And amount, element substitution site, particle generation reaction conditions, etc.
I can do it. The saturation magnetization σs is 40 to 80 A · m²/ Kg
is there. Higher σs is preferable, but smaller as it becomes finer
Tend to be. Magnet Plan Buy to improve σs
Compounding spinel ferrite with
The selection of the kind of element and the amount added is well known. Ma
It is also possible to use W-type hexagonal ferrite. Magnetism
When dispersing the particles, the surface of the magnetic particles is dispersed in a dispersion medium or polymer.
It is also being processed with substances that suit the requirements. surface treatment
The material is an inorganic compound or an organic compound. Main compounds
As oxides or hydroxides of Si, Al, P, etc.
Various silane coupling agents, various titanium coupling agents
Is a representative example. The amount is 0.1 to 10% with respect to the magnetic substance.
is there. The pH of the magnetic material is also important for dispersion. Usually 4-12
There is an optimum value depending on the dispersion medium and polymer.
About 6 to 11 is selected in view of chemical stability and storage stability.
Water contained in the magnetic material also affects the dispersion. Dispersion medium, poly
There is an optimum value depending on the color, but usually 0.01 to 2.0% is selected.
It is released. The manufacturing method of hexagonal ferrite is (1) oxidation.
Metal oxide and glass form to replace barium, iron oxide, iron
Boron oxide or the like as a constituent material is made into a desired ferrite composition.
So that it is melted and rapidly cooled to form an amorphous material.
After reheating, wash and grind
Glass crystallization method to obtain the crystal powder
A by-product of neutralizing a salt solution of a cerite composition with alkali
After removing the liquid, it is heated in a liquid phase at 100 ° C.
・ Hydrothermal reaction to obtain barium ferrite crystal powder by grinding
(3) Barium ferrite composition metal salt solution
Neutralize with water, remove by-products and dry
Treated under and pulverized to obtain barium ferrite crystal powder
However, the present invention does not select a production method. [Non-magnetic layer] Next, there is a gap between the support and the magnetic layer.
Detailed contents regarding the lower layer when the nonmagnetic layer is provided
Will be described. The lower layer of the present invention is substantially non-magnetic.
Its configuration should not be limited, but usually
Consisting of at least a resin, preferably a powder, for example
Inorganic powder or organic powder dispersed in resin
Can be mentioned. The inorganic powder is usually preferably a non-magnetic powder.
Magnetic powder in the range where the lower layer is substantially non-magnetic
The powder can also be used. Examples of the nonmagnetic powder include metal oxidation.
, Metal carbonate, metal sulfate, metal nitride, metal carbonization
Or inorganic compounds such as metal sulfides
The As an inorganic compound, for example, α-
Alumina, β-alumina, γ-alumina, θ-aluminum
Na, silicon carbide, chromium oxide, cerium oxide, α-oxidation
Iron, hematite, goethite, corundum, silicon nitride,
Titanium carbide, titanium oxide, silicon dioxide, oxide oxide
, Magnesium oxide, tungsten oxide, zirconium oxide
Ni, boron nitride, zinc oxide, calcium carbonate, sulfuric acid
Calcium, barium sulfate, molybdenum disulfide, etc.
Used alone or in combination. Particularly preferred is a particle size
Diacids due to the small distribution and many functions
Titanium oxide, zinc oxide, iron oxide, barium sulfate,
Of these, titanium dioxide and alpha iron oxide are preferred. these
The nonmagnetic powder particle size is preferably 0.005 to 2 μm.
However, if necessary, combine non-magnetic powders with different particle sizes.
Widening the particle size distribution even with a single non-magnetic powder.
Can have the same effect. Especially preferred
The particle size of non-magnetic powder is 0.01 μm to 0.2
μm. In particular, the non-magnetic powder is a granular metal oxide
In the case, the average particle size is preferably 0.08 μm or less, and is needle-like
In the case of a metal oxide, the long axis length is preferably 0.3 μm or less.
More preferably, it is 0.2 μm or less. Tap density
Is usually 0.05-2 g / ml, preferably 0.2-1.5.
g / ml. The moisture content of non-magnetic powder is usually 0.1-5
% By weight, preferably 0.2 to 3% by weight, more preferably
0.3 to 1.5% by mass. The pH of the non-magnetic powder is
Usually it is 2-11, but the pH is particularly between 5.5-10.
preferable. The specific surface area of non-magnetic powder is usually 1-100m²
/ g, preferably 5 to 80 m²/ g, more preferably 10
70m²/ g. The crystallite size of the non-magnetic powder is 0.00
4 μm to 1 μm is preferable, 0.04 μm to 0.1 μm
Is more preferable. Using DBP (dibutyl phthalate)
The oil absorption is 5 to 100 ml / 100 g, preferably 10 to 80 m.
1/100 g, more preferably 20 to 60 ml / 100 g. ratio
The weight is 1-12, preferably 3-6. The shape is needle-shaped,
Any of a spherical shape, a polyhedral shape, and a plate shape may be used. Mohs hardness is
4 or more and 10 or less are preferable. Non-magnetic powder SA
(Stearic acid) Adsorption amount is 1-20μmol / m²Preferred
2-15μmol / m², More preferably 3-8μ
mol / m²It is. The pH is preferably between 3 and 6
Yes. The surface of these nonmagnetic powders is subjected to a surface treatment.
l₂O_Three, SiO₂TiO₂, ZrO₂, SnO₂,
Sb₂O_Three, ZnO, Y₂O_ThreeIs preferred to exist
Yes. Particularly preferred for dispersibility is Al.₂O_Three, SiO₂,
TiO₂, ZrO₂More preferred is Al₂
O_Three, SiO₂, ZrO₂It is. These are combinations
Can be used alone, or can be used alone. Ma
Alternatively, a co-precipitated surface treatment layer may be used depending on the purpose.
First, after alumina is present, the surface layer is made of silica.
You can also take the process or vice versa
The The surface treatment layer can be a porous layer depending on the purpose.
Although it does not matter, it is generally preferable to be homogeneous and dense. Nonmagnetic powder tool used in the lower layer of the present invention
Physical examples include Showa Denko Nano Tight, Sumitomo Chemical
HIT-100, ZA-G1, α Hematai manufactured by Toda Kogyo Co., Ltd.
DPN-250, DPN-250BX, DPN-24
5, DPN-270BX, DPN-500BX, DBN
-SA1, DBN-SA3, Ishihara Sangyo Titanium Oxide TT
O-51B, TTO-55A, TTO-55B, TTO
-55C, TTO-55S, TTO-55D, SN-1
00, α hematite E270, E271, E300, E
303, Titanium Industry Titanium Oxide STT-4D, STT
-30D, STT-30, STT-65C, α Hematai
G-40, Teika MT-100S, MT-100
T, MT-150W, MT-500B, MT-600
B, MT-100F, MT-500HD, Sakai Chemicals FI
NEX-25, BF-1, BF-10, BF-20, S
TM, DEFIC-Y, DEFIC-R made by Dowa Mining
Nippon Aerosil AS2BM, TiO2P25, Ube Ko
100A, 500A manufactured by the company,
I can get lost. Particularly preferred nonmagnetic powders are titanium dioxide and α.
-Iron oxide. Known by mixing carbon black in the lower layer
Lowering the surface electrical resistance Rs, which is the effect of
As well as the desired microbi
Kerr hardness can be obtained. Also, the lower layer is carbon
The effect of storing the lubricant is brought about by including black
It is also possible. The type of carbon black is rubber rubber
Furness, rubber thermal, color black, acetyl
Ren black or the like can be used. Lower carbo
Depending on the desired effect,
Should be optimized.
May be. The specific surface area of the underlying carbon black is generally
Usually 100-500m²/ G, preferably 150-40
0m²/ G, DBP oil absorption is usually 20 to 400 ml / 100
g, preferably 30 to 400 ml / 100 g. Carbon tube
The particle diameter of the rack is usually 5 to 80 nm, preferably 10 to 10 nm.
50 nm, more preferably 10 to 40 nm. Mosquito
-The pH of Bon Black is 2-10, and the water content is 0.1-1.
0% and the tap density are preferably 0.1 to 1 g / ml. Main departure
As a concrete example of carbon black used for light
BLACKPEARLS 2000, 1 manufactured by Cabot Corporation
300, 1000, 900, 800, 880, 700,
VULCAN XC-72, Mitsubishi Chemical Industries, Ltd. # 305
0B, # 3150B, # 3250B, # 3750B, #
3950B, # 950, # 650B, # 970B, # 8
50B, MA-600, MA-230, # 4000, #
4010, CONDUCT made by Columbian Carbon
EX SC, RAVEN 8800, 8000, 700
0,5750,5250,3500,2100,200
0, 1800, 1500, 1255, 1250, Akzo
-Ketjen Black EC manufactured by the company. car
Bon black is surface treated with a dispersant, etc.
Even if it is used after rafting, part of the surface is graphitized.
You may use what you did. Carbon bra
Disperse it with a binder before adding it to the paint.
It doesn't matter. These carbon blacks are inorganic
Non-magnetic layer total in a range not exceeding 50% by mass with respect to the powder
It can be used within a range not exceeding 40% of the amount. These cars
Bon black can be used alone or in combination.
Yes. The carbon black that can be used in the present invention is, for example,
“Carbon Black Handbook” (Carbon Black Association)
Can be helpful. In the lower layer, an organic powder is used depending on the purpose.
It can also be added. For example, acrylic styrene tree
Fat powder, benzoguanamine resin powder, melamine resin powder
Powders such as phthalocyanine pigments
Tin resin powder, polyester resin powder, polyamide
Resin powder, polyimide resin powder, polyfluoroethylene
Resin can also be used. The production method is disclosed in JP-A-62.
-18564, described in JP-A-60-255827
Something like that can be used. Lower layer binder resin, moisture
Lubricants, dispersants, additives, solvents, dispersion methods, etc. are as follows.
The magnetic layer described can be applied. In particular, binder resin
The amount, type, additive, amount of added dispersant, type
A known technique relating to the adhesive layer can be applied. [Binder] As a binder used in the present invention.
Conventionally known thermoplastic resins, thermosetting resins, reactive trees
Fats and mixtures thereof are used. As a thermoplastic resin
Has a glass transition temperature of −100 to 150 ° C., a number average molecule
The amount is 1,000-200,000, preferably 10,000
0 to 100,000, the degree of polymerization is about 50 to 1000
Is. Examples of such are vinyl chloride, acetic acid.
Vinyl, vinyl alcohol, maleic acid, acrylic acid,
Acrylic acid ester, vinylidene chloride, acrylonitrile
Methacrylic acid, methacrylic acid ester, styrene,
Butadiene, ethylene, vinyl butyral, vinyl acetate
Polymerization containing tar, vinyl ether, etc. as constituent units
Body or copolymer, polyurethane resin, various rubber resins
There is. In addition, as thermosetting resin or reactive resin
Phenolic resin, epoxy resin, polyurethane cured tree
Fat, urea resin, melamine resin, alkyd resin, acrylic
System reaction resin, formaldehyde resin, silicone resin,
Epoxy-polyamide resin, polyester resin and isocyanate
Anate prepolymer mixture, polyester polyol
Mixture of polyurethane and polyisocyanate, polyurethane and polyisocyanate
And a mixture of isocyanates. These resins
About “Plastic Handbook” published by Asakura Shoten
Is described in detail. Also known electron beam curing
It is also possible to use a mold resin for each layer. These examples
And the manufacturing method thereof are disclosed in JP-A-62-2256219.
It is described in detail. These resins are single or combination
Vinyl chloride resin as a preferable one,
Vinyl chloride vinyl acetate copolymer, vinyl chloride vinyl acetate
Vinyl alcohol copolymer, vinyl chloride vinyl acetate anhydrous
Maleic acid copolymer, at least one selected from
Polyurethane resin combinations or polyisocyanates
A combination of nates. The structure of the polyurethane resin is polyester.
Polyurethane, polyether polyurethane, polyether
Polyester polyurethane, polycarbonate polyure
Tan, Polyester Polycarbonate, Polyurethane, Poly
Uses well-known materials such as licaprolactone polyurethane
Yes. Better for all the binders listed here
-COO if necessary to obtain high dispersibility and durability
M, -SO_ThreeM, -OSO_ThreeM, -P = O (OM)₂,
-OP = O (OM)₂, (Where M is a hydrogen atom,
Or alkali metal base), OH, NR₂, N⁺R
_Three(R is a hydrocarbon group), epoxy group, SH, CN, etc.
Copolymerize at least one polar group selected from
Or it is preferable to use the one introduced by addition reaction.
Yes. The amount of such polar groups is 10^-1-10^-8In mol / g
Yes, preferably 10^-2-10^-6Mol / g. Specific examples of these binders used in the present invention
Examples include VAGH and VY manufactured by Union Carbide.
HH, VMCH, VAGF, VAGD, VROH, VY
ES, VYNC, VMCC, XYHL, XYSG, PK
HH, PKHJ, PKHC, PKFE, Nissin Chemical Industry Co., Ltd.
Manufactured by MPR-TA, MPR-TA5, MPR-TAL,
MPR-TSN, MPR-TMF, MPR-TS, MP
R-TM, MPR-TAO, Denki Kagaku 1000W,
DX80, DX81, DX82, DX83, 100F
D, ZEON Corporation MR-104, MR-105, MR
110, MR100, MR555, 400X-110
A, Nipponran N2301, N2 manufactured by Nippon Polyurethane
302, N2304, Pandex T manufactured by Dainippon Ink
-5105, T-R3080, T-5201, Barnock
D-400, D-210-80, Crisbon 610
9, 7209, Byron UR8200, UR manufactured by Toyobo Co., Ltd.
8300, UR-8700, RV530, RV280,
Daifera Seika Co., Ltd., Daiferamin 4020, 5020, 5
100, 5300, 9020, 9022, 7020, three
Ryo Kasei Co., Ltd., MX5004, Sanyo Kasei Co., Ltd. Sampler S
P-150, Asahi Kasei Corporation Saran F310, F210, etc.
Can be given. The bonding used in the nonmagnetic layer and magnetic layer of the present invention.
The mixture is 5-50 quality compared to non-magnetic powder or ferromagnetic powder.
Used in the range of% by mass, preferably in the range of 10 to 30% by mass
It is done. 5-30 mass when using vinyl chloride resin
%, 2-20 mass% when using polyurethane resin,
These polyisocyanates are in the range of 2-20% by weight.
Although it is preferable to use in combination, for example, a trace amount
If head corrosion occurs due to dechlorination, polyurethane
Use only or polyurethane and isocyanate only
It is also possible. In the present invention, polyurethane is used.
When used, the glass transition temperature is preferably -50 to 150 ° C.
Or 0 ° C to 100 ° C, more preferably 30 ° C to 90 ° C.
° C, elongation at break of 100-2000%, break stress is usually
0.05 to 10 kg / mm²(≒ 0.49 ~ 98MP
a) The yield point is 0.05 to 10 kg / mm.²(≒ 0.4
9 to 98 MPa) is preferable. The magnetic recording medium of the present invention comprises two or more layers.
Can be done. Therefore, the amount of binder and the amount of vinyl chloride in the binder.
Nyl resin, polyurethane resin, polyisocyanate,
Or other resin amount, each resin forming the magnetic layer
Molecular weight, polar group weight, or physical properties of the resin
It is possible to change the properties such as non-magnetic layer and magnetic layer as necessary
Of course it is possible, rather it should be optimized at each layer
Thus, a known technique relating to the multilayer magnetic layer can be applied. example
For example, when changing the amount of binder in each layer, scratches on the surface of the magnetic layer
To reduce the amount of binder in the magnetic layer.
It is effective and improves the head touch to the head.
To achieve this, increase the amount of binder in the nonmagnetic layer to provide flexibility.
Can be. As the polyisocyanate used in the present invention,
Is tolylene diisocyanate, 4,4'-diphenyl
Methane diisocyanate, hexamethylene diisocyanate
, Xylylene diisocyanate, naphthylene-1,
5-diisocyanate, o-toluidine diisocyanate
, Isophorone diisocyanate, triphenylmethane
Isocyanates such as triisocyanate and the like
Products of these isocyanates and polyalcohols
Polyisocyanate formed by condensation of isocyanates
Cyanate and the like can be used. These isoshi
Commercially available product names of anates include Nippon Poly
Urethane, Coronate L, Coronate HL, Corone
2030, Coronate 2031, Millionate M
R, Millionate MTL, Takeda Pharmaceutical, Takenate D
-102, Takenate D-110N, Takenate D-2
00, Takenate D-202, manufactured by Sumitomo Bayer, Death
Module L, Death Module IL, Death Module
N, Death Module HL, etc.
Two or more combinations using differences in cure reactivity
Therefore, each layer can be used. [Carbon black, abrasive] Magnet of the present invention
Carbon black used for the protective layer is a rubber furnace.
, Rubber thermal, color black, acetylene rubber
A rack, etc. can be used. Specific surface area is 5-50
0m²/ G, DBP oil absorption is 10 to 400 ml / 100
g, particle diameter is 5 nm to 300 nm, preferably 10 to 2
50 nm, more preferably 20 to 200 nm. p
H is 2 to 10, moisture content is 0.1 to 10%, tap density is
0.1-1 g / cc is preferable. The mosquito used in the present invention
-As a specific example of Bon Black, manufactured by Cabot Corporation,
BLACKPEARLS 2000, 1300, 100
0, 900, 905, 800, 700, VULCAN
XC-72, manufactured by Asahi Carbon Co., # 80, # 60, # 5
5, # 50, # 35, manufactured by Mitsubishi Chemical Industries, # 2400
B, # 2300, # 900, # 1000 # 30, # 4
0, # 10B, made by Columbian Carbon, CONDU
CTEX SC, RAVEN 150, 50, 40, 1
5, RAVEN-MT-P, manufactured by Japan EC, Ketjen
Black EC, etc. Carbon black
Surface treatment with a dispersant or grafting with a resin
Even if it is used, the part of the surface is graphitized
It doesn't matter. Carbon black is also used as a magnetic paint.
It may be dispersed with a binder before adding to
Yes. These carbon blacks can be used alone or in combination
Can be used. When to use carbon black
If used, it should be 0.1-30% of the amount of the magnetic material.
Is preferred. Carbon black is an antistatic, anti-friction magnetic layer.
Functions such as reducing the friction coefficient, imparting light-shielding properties, and improving film strength
These differ depending on the carbon black used. Obedience
These carbon blacks used in the present invention are
Change the type, amount, and combination of the magnetic layer and lower non-magnetic layer.
Particle size, oil absorption, conductivity, pH, etc.
Of course, it can be used according to the purpose based on the various characteristics.
Rather, it should be optimized at each layer.
Carbon black that can be used in the magnetic layer of the present invention is, for example,
“Carbon Black Handbook” edited by Carbon Black Association
Can be helpful. As the abrasive used in the present invention, the alpha conversion rate is used.
90% or more of α-alumina, β-alumina, silicon carbide
Element, chromium oxide, cerium oxide, α-iron oxide, colanda
, Artificial diamond, silicon nitride, silicon carbide titanium car
Bite, titanium oxide, silicon dioxide, boron nitride, etc.
As a known material with a Mohs hardness of 6 or more alone or in combination
Used. Also, a composite of these abrasives
(Abrasives surface-treated with other abrasives)
Also good. These abrasives include compounds other than the main component or
It may contain elements, but if the main component is 90% or more
There is no change in the effect. The particle size of these abrasives is
0.01-2 μm is preferred, more preferably 0.05
-1.0 μm, particularly preferably 0.05-0.5 μm
It is a range. In particular, to improve the electromagnetic conversion characteristics,
A narrow particle size distribution is preferred. Also improve durability
If necessary, combine abrasives with different particle sizes
The same effect can be obtained by widening the particle size distribution even with a single abrasive.
It is also possible to bring fruit. Tap density is 0.3 ~
2g / cc, moisture content 0.1-5%, pH 2-11, ratio table
The area is 1-30m²/ g is preferred. Used in the present invention
The shape of the abrasive is acicular, spherical, or dice
However, those with corners in part of the shape are highly abrasive.
preferable. Specifically, AKP-12, AK manufactured by Sumitomo Chemical Co., Ltd.
P-15, AKP-20, AKP-30, AKP-5
0, HIT20, HIT-30, HIT-55, HIT
60, HIT70, HIT80, HIT100, Reino
Luz, ERC-DBM, HP-DBM, HPS-D
BM, manufactured by Fujimi Abrasive Co., Ltd., WA10000, Uemura Kogyo Co., Ltd.
UB20, Nippon Chemical Industry Co., Ltd., G-5, Kromec
Su2, Chromex U1, Toda Kogyo Co., TF10
0, TF140, IBIDEN, Beta Random Wool
Rafine, Showa Mining Co., Ltd., B-3, etc. are mentioned.
These abrasives can be added to the nonmagnetic layer as needed.
it can. The surface shape was controlled by adding to the nonmagnetic layer.
In other words, the protruding state of the abrasive can be controlled.
The particle size and amount of abrasive added to these magnetic and nonmagnetic layers is
Of course, it should be set to the optimum value. [Additive] Used in the magnetic layer and nonmagnetic layer of the present invention.
Additives used include lubrication effect, antistatic effect,
What has a scattering effect, a plastic effect, etc. is used. Disulfur
Molybdenum, tungsten disulfide graphite, nitriding
Boron, fluorinated graphite, silicone oil, with polar group
Silicone, fatty acid-modified silicone, fluorine-containing silicon
, Fluorine-containing alcohol, fluorine-containing ester,
Reolefin, polyglycol, alkyl phosphate ester
And its alkali metal salts, alkyl sulfates and
And its alkali metal salts, polyphenyl ether, pheny
Phosphonic acid, alpha naphthyl phosphoric acid, phenyl phosphoric acid, diphen
Nyl phosphoric acid, p-ethylbenzenephosphonic acid, phenylphospho
Sphinic acid, aminoquinones, various silane couplings
Agent, titanium coupling agent, fluorine-containing alkyl sulfate
Steal and its alkali metal salts, C10-24
Monobasic fatty acids (including unsaturated bonds, also branched
And any of these metal salts (Li,
Na, K, Cu, etc.) or one having 12 to 22 carbon atoms
, Divalent, trivalent, tetravalent, pentavalent, hexavalent alcohol,
Including union or branching)
C12-C22 alkoxy alcohol, C10
~ 24 monobasic fatty acids (including unsaturated bonds,
It may be branched) and a monovalent carbon number of 2 to 12,
One of divalent, trivalent, tetravalent, pentavalent, hexavalent alcohol
One (may contain unsaturated bonds or be branched)
Mono-fatty acid ester or di-fatty acid ester
Steal or tri fatty acid ester, alkylene oxide
Polymer monoalkyl ether fatty acid ester, carbon
Fatty acid amide having 8 to 22 carbon atoms, aliphatic amine having 8 to 22 carbon atoms
Min, etc. can be used. Specific examples of these include fatty acids and caps.
Phosphoric acid, caprylic acid, lauric acid, myristic acid, pal
Mytic acid, stearic acid, behenic acid, oleic acid, ella
Idic acid, linoleic acid, linolenic acid, isostearin
Acid, and the like. Butyl stearate for esters
Octyl stearate, amyl stearate,
Sooctyl stearate, butyl myristate, oct
Lumilyst, Butoxyethyl stearate, Butoki
Sidiethyl stearate, 2-ethylhexyl stearate
2-octyldodecyl palmitate, 2-hexi
Ludodecyl palmitate, isohexadecyl stearate
Oleyl oleate, dodecyl stearate, tri
Decyl stearate, oleyl erucate, neopentyl
Glycol didecanoate, ethylene glycol diole
Oleyl alcohol, stearyl
Lualcohol, lauryl alcohol, etc.
The In addition, alkylene oxide, glycerin,
Ricidol-based, alkylphenol ethylene oxide
Nonionic surfactants such as adducts, cyclic amines, esthetics
Luamide, quaternary ammonium salts, hydantoin derivatives
Bodies, heterocycles, phosphonium or sulfoniums, etc.
Cationic surfactant, carboxylic acid, sulfonic acid,
Acidic groups such as phosphoric acid, sulfuric acid ester groups, and phosphoric acid ester groups
Anionic surfactant, amino acids, aminosulfo
Acids, sulfuric or phosphoric acid esters of amino alcohol
, Amphoteric surfactants such as alkylbedine type
it can. For these surfactants, see “Surfactants.
Handbook ”(published by Sangyo Tosho Co., Ltd.)
The These lubricants, antistatic agents, etc. are not necessarily 100%
Not pure, other than the main components, isomers, unreacted substances, side reactions
May contain impurities, decomposition products, oxides, etc.
Yes. These impurities are preferably 30% or less, more preferably
Preferably it is 10% or less. These lubricants and interfaces used in the present invention
Activators are those that have different physical effects,
The type, amount, and combination of lubricants that produce a synergistic effect
The usage ratio should be optimally determined according to the purpose.
Use non-magnetic and magnetic layers with different melting points on the surface.
S with different boiling point, melting point and polarity to control bleeding
Surface activity that controls bleeding on the surface using tellurium
Lubrication that improves coating stability by adjusting the dosage
Do not increase the additive amount in the intermediate layer to improve the lubrication effect
Of course, it is limited to the example shown here.
There is no. Generally, the total amount of lubricant is magnetic or non-magnetic.
0.1% -50%, preferably 2% -2
It is selected in the range of 5%. Also, all of the additives used in the present invention.
Or part of which process in the production of magnetic and non-magnetic coatings
May be added, for example, a magnetic material before the kneading step.
When mixing with a magnetic material, binder and solvent kneading process
When adding at the dispersion step, add at the dispersion step.
In some cases, it is added just before coating. Ma
Depending on the purpose, after applying the magnetic layer, simultaneously or sequentially
By applying some or all of the additive
The objective may be achieved. Depending on the purpose,
After rendering or after slitting, on the magnetic layer surface
A lubricant can also be applied. Used in the present invention
As the organic solvent, known ones can be used, for example, JP-A-6-68.
The solvent described in 453 can be used. [Layer Structure] The thickness structure of the magnetic recording medium of the present invention.
The substrate is 2 to 100 μm, preferably 2 to 80 μm.
It is. Computer tape support is 3.0 ~
6.5 μm (preferably 3.0 to 6.0 μm, more preferably
The thickness is preferably in the range of 4.0 to 5.5 μm.
used. Between the smooth coating layer and the nonmagnetic layer or magnetic layer
An undercoat layer may be provided to improve adhesion. This
The coating layer thickness is 0.01 to 0.5 μm, preferably 0.02.
˜0.5 μm. The present invention is usually non-magnetic on both sides of the support.
A double-sided magnetic layer disk-shaped medium comprising a layer and a magnetic layer
However, it may be provided only on one side. In this case, the belt
Non-magnetic layer for effects such as electric prevention and curl correction,
A back layer may be provided on the side opposite to the magnetic layer side. This
Has a thickness of 0.1 to 4 μm, preferably 0.3 to 2.0 μm
m. For these undercoat and back layers, use known ones.
Can be used. The thickness of the magnetic layer of the medium of the present invention is the same as the head used.
Saturation amount of head, head gap length, recording signal bandwidth
It is more optimized. Magnetic layer with different magnetic properties
It may be separated into two or more layers having a known multi-layer magnetism.
A configuration relating to the sex layer can be applied. If the lower layer is substantially non-magnetic, its effect
For example, as an impurity or
A small amount of magnetic material may be included. Substantially non-magnetic and
The residual magnetic flux density of the lower layer is 0.1T or less or the coercive force is 8
kA / m or less, preferably residual magnetic flux density
It shows no degree and no coercive force. [Back layer] Generally, computer data
Magnetic tapes for recording are video tapes and audio tapes.
Compared to the above, repeatability is strongly required. this
In order to maintain such high running durability
Must contain carbon black and inorganic powder
Is preferred. Carbon black has a different average particle size.
It is preferable to use a combination of two types
Yes. In this case, fine particles having an average particle size of 10 to 20 nm
Child carbon black and average particle size of 230-30
Used in combination with 0 nm coarse particulate carbon black
It is preferable to do. In general, the fine particles
By adding carbon black, the surface electrical resistance of the back layer
The resistance can be set low, and the light transmittance can be set low. Magnetism
Some recording devices use the light transmittance of the tape to
Since there are many things used for the signal of the work,
In particular, the addition of particulate carbon black is useful.
It becomes effective. Also, particulate carbon black is generally liquid
Excellent retention of lubricant, reducing friction coefficient when used with lubricant
Contributes to On the other hand, the particle size is 230 to 300 nm.
Coarse particulate carbon black is a solid lubricant
Have micro-protrusions on the surface of the back layer
Reduce the contact area and contribute to the reduction of the friction coefficient.
The Specific products of particulate carbon black
The following can be mentioned. RAVE
N2000B (18nm), RAVEN1500B (1
7nm) (above, Columbia Carbon Co., Ltd.), BP80
0 (17 nm) (manufactured by Cabot), PRINTEX
90 (14 nm), PRINTEX 95 (15 nm),
PRINTEX85 (16nm), PRINTEX75
(17 nm) (above, manufactured by Degussa), # 3950 (16
nm) (Mitsubishi Chemical Industry Co., Ltd.). Further, the specific quotient of coarse particle carbon black
Examples of products include thermal black (270 nm)
Nencarb Co., Ltd.), RAVEN MTP (275 nm)
(Made by Columbia Carbon Co., Ltd.). In the back layer, the average particle size is different.
When using two types of
Child carbon black and coarse particles of 230-300 nm
The content ratio (mass ratio) of carbon black is the former: the latter
= Preferably in the range of 98: 2 to 75:25,
More preferably, it is the range of 95: 5-85: 15. Carbon black in the back layer (two types
When using things, the total amount) content is bound
Usually in the range of 30-80 parts by mass with respect to 100 parts by mass of the agent
Preferably, it is the range of 45-65 mass parts. Two kinds of inorganic powders having different hardnesses are used.
It is preferable to use together. Specifically, Mohs hardness 3
4.5 soft inorganic powder and Mohs hardness 5-9 hard inorganic powder
It is preferable to use powder. Mohs hardness of 3-4.
By adding 5 soft inorganic powder,
The friction coefficient can be stabilized. And this category
Due to the hardness of the enclosure, the sliding guide pole may not be cut off.
Yes. The average particle size of this inorganic powder is 30-50.
It is preferably in the range of nm. Soft inorganic powder having a Mohs hardness of 3 to 4.5;
For example, calcium sulfate, calcium carbonate, silica
Calcium acid, barium sulfate, magnesium carbonate, carbonic acid
Zinc and zinc oxide can be mentioned. They are,
Use alone or in combination of two or more
Can do. The content of the soft inorganic powder in the back layer is
-10 to 140 masses per 100 mass parts of Bon Black
Part of the range, more preferably 35
-100 mass parts. Add hard inorganic powder with Mohs hardness of 5-9
By doing so, the strength of the back layer is enhanced and the running durability
Improves. These inorganic powders are carbon black and
When used with the soft inorganic powder, it is suitable for repeated sliding.
Even so, there is little deterioration and it becomes a strong back layer. Also this nothing
Appropriate polishing force is given by adding machine powder, and the tape
The adhesion of shavings to the guide pole etc. is reduced. Especially soft
When used in combination with inorganic powder, the guide pole has a rough surface.
All the sliding characteristics are improved and the friction coefficient of the back layer is stabilized.
Can be planned. The hard inorganic powder has an average particle size of 8
0 to 250 nm (more preferably, 100 to 210 n
m) is preferable. Hard inorganic powder with Mohs hardness of 5-9
For example, α-iron oxide, α-alumina, and oxide oxide
Rom (Cr₂O_Three). These powders
The powder may be used alone or in combination.
May be. Among these, α-iron oxide or α-aluminum
Na is preferred. Hard inorganic powder content is carbon bra
It is usually 3 to 30 parts by mass with respect to 100 parts by mass of the pack,
Preferably, it is 3-20 mass parts. The soft inorganic powder and the hard inorganic powder are used for the back layer.
When using powder together, soft inorganic powder and hard inorganic powder
Hardness difference is 2 or more (more preferably 2.5 or more, special
3 or more) soft inorganic powder and hard inorganic powder
It is preferable to select and use. In the back layer, each of the specific average grains
Two types of inorganic powders with different sizes and different Mohs hardness
And two types of carbon bras with different average particle sizes.
It is preferable to contain The back layer may contain a lubricant.
it can. The lubricant may be the nonmagnetic layer or the magnetic layer described above.
As appropriate, select from the lubricants listed above.
Can be used. In the back layer, the lubricant is bonded
Usually added in the range of 1-5 parts by weight per 100 parts by weight of the agent
Is done. [Support] In the present invention, the smooth coating layer comprises
The support provided is not particularly limited
However, it is preferably substantially non-magnetic and flexible. The present invention
As a flexible support used in
Polyesters such as tarates and polyethylene naphthalates
Rubbers, polyolefins, cellulose triacetate,
Polycarbonate, polyimide, polyamideimide, polyester
Lisulfone, aromatic polyamide or aliphatic polyamide
Use known films such as glass and polybenzoxazole
Can be used. Polyethylene naphthalate, polyamide, etc.
It is preferable to use a high strength support. If necessary
In order to change the surface roughness of the magnetic surface and the base surface,
-A laminated type support as shown in -224127
It can also be used. These supports are pre-loaded.
Rona discharge treatment, plasma treatment, easy adhesion treatment, heat treatment, removal
You may perform dust processing. The support of the present invention
It is also possible to apply aluminum or glass substrate as
is there. In order to achieve the object of the present invention, a support is used.
Center plane average table measured with TOPO-3D manufactured by WYKO
The surface roughness Ra is preferably about 8.0 nm or less. Main departure
As for Ming, Ra can be set low by the smooth coating layer.
Can cope with even large Ra and is advantageous in terms of cost
It is. These supports are coarse protrusions of 0.5 μm or more
It is preferable that there is no. The surface roughness shape can be adjusted as necessary.
Depending on the size and amount of filler added to the support.
It is something to be controlled. These fillers
As an example, oxides such as Ca, Si, Ti, etc.
In addition to carbonates, organic powders such as acrylic are listed.
Maximum height Rmax of support is 1 μm or less, 10-point average roughness
Rz is 0.5 μm or less, and the center surface peak height Rp is 0.5 μm.
Below, the central plane valley depth Rv is 0.5 μm or less, and the central plane area
The rate Sr is 10% or more and 90% or less, and the average wavelength λa is 5 μm.
m or more and 300 μm or less are preferable. Desired electromagnetic conversion characteristics
Distribution of surface protrusions on these supports to improve durability and durability
It can be arbitrarily controlled by a filler,
0.1mm for each of the size of 0.01-1μm²Ah
Can be controlled in the range of 0 to 2000
Yes. The F-5 value of the support used in the present invention is preferably
5 to 50 kg / mm²(≒ 49-490MPa)
Further, the heat shrinkage rate of the support at 100 ° C. for 30 minutes is preferably
3% or less, more preferably 1.5% or less, 80 ° C. 30
The heat shrinkage in minutes is preferably 1% or less, more preferably
Is 0.5% or less. Breaking strength is 5-100Kg / m
m²(≈49 to 980 MPa), elastic modulus is 100 to 20
00Kg / mm²(≒ 0.98 ~ 19.6GPa) is preferred
Good. The coefficient of thermal expansion is 10^-Four-10^-8/ ℃, good
Preferably 10^-Five-10^-6/ ° C. Humidity expansion coefficient is 1
0^-Four/ RH% or less, preferably 10^-Five/ RH% or less
It is below. These thermal characteristics, dimensional characteristics, and mechanical strength characteristics are
Almost equal with a difference of 10% or less in each direction in the plane of the support
It is preferable. [Production Method] Magnetic Coating of the Magnetic Recording Medium of the Present Invention
The process of manufacturing the material and non-magnetic coating is at least a kneading
As needed, before and after the dispersion process and before and after these processes
The mixing step. Each process has two stages
It doesn't matter if it is divided above the floor. Used in the present invention
Magnetic material, non-magnetic powder, binder, carbon black, polishing
All raw materials such as chemicals, antistatic agents, lubricants and solvents
It may be added at the beginning or in the middle of the process. Also,
Individual ingredients may be added in two or more steps.
I don't know. For example, a polyurethane kneading step, a dispersing step,
Split in the mixing process for viscosity adjustment after dispersion.
Also good. In order to achieve the object of the present invention, the conventional known
This manufacturing technique can be used as a part of the process. Mixed
In the kneading process, open kneader, continuous kneader, pressure kneader,
Use a material with strong kneading force such as an extruder.
Are preferred. When using a kneader, magnetic or non-magnetic
All or part of powder and binder (however, all bonds
30% or more of the agent) and 100 parts of magnetic material
And kneading in the range of 15 to 500 parts. These blends
For details of the kneading process, see JP-A-1-106338, JP
1-79274. Magnetic layer solution
Glass beads are used to disperse the nonmagnetic layer liquid
Zirconi is a high specific gravity dispersion medium
Abies, titania beads, steel beads are preferred
The The particle size and filling rate of these dispersion media should be optimized.
I can. Dispersers can use known ones
The In the present invention, a magnetic recording medium having a multilayer structure is applied.
In this case, it is preferable to use the following method. First
First, a gravure coating commonly used in the application of magnetic paints
Cloth, roll coating, blade coating, extrusion coating
First, apply the lower layer with a cloth device, etc., and the lower layer is wet.
Japanese Patent Publication No. 1-46186 and JP-A-60-238
179, the support disclosed in JP-A-2-265672.
Apply the upper layer with body pressure type extrusion coating equipment
how to. Secondly, JP-A-63-88080 and JP-A-2-
17971, and disclosed in JP-A-2-265672.
One coating head that contains two slits for coating solution
A method in which the upper and lower layers are applied almost simultaneously using a lid. Third, special
The backup robot disclosed in Kaihei 2-174965
The upper and lower layers are removed by an extrusion coating device with a handle.
This is a method of applying at the same time. For aggregation of magnetic particles
To prevent deterioration of electromagnetic conversion characteristics of magnetic recording media
Therefore, JP-A-62-295174 and JP-A-1-236968.
The coating inside the coating head by a method as disclosed in
It is desirable to apply shear to the cloth fluid. Furthermore, application
The viscosity of the liquid is disclosed in JP-A-3-8471.
It is necessary to satisfy the numerical range. The configuration of the present invention is implemented.
To reveal, after applying and drying the lower layer, magnetic
Of course, it does not matter if you use sequential multilayer coating to provide layers,
The effect of the present invention is not lost. However, lack of application
Reduce traps and improve dropout quality
For this purpose, it is preferable to use the above-mentioned simultaneous multilayer coating.
Yes. In the case of a disc, no orientation is used without using an orientation device.
However, a sufficiently isotropic orientation may be obtained.
Arrange the baltic magnets diagonally alternately, with solenoid
Using a known random orientation device, such as applying an alternating magnetic field
It is preferable. Isotropic orientation refers to ferromagnetic metal powder
In general, in-plane two-dimensional random is preferable, but
It is possible to make a three-dimensional random with a direct component.
In the case of hexagonal ferrite, generally in-plane and perpendicular
In-plane 2D random
It is also possible. Also known as a different pole opposing magnet
Method and isotropic in the circumferential direction by vertical alignment
Magnetic properties can also be imparted. Especially high density recording
In this case, the vertical alignment is preferable. Also use spin coat
A circumferential orientation may be used. In the case of magnetic tape, a cobalt magnet or soreno
Oriented in the longitudinal direction using id. Dry wind temperature, wind
By controlling the amount and coating speed, the drying position of the coating film can be controlled.
The coating speed is preferably 20 m / min to 1
000m / min, and the drying air temperature is preferably 60 ° C or higher.
Moderate pre-drying before entering the magnet zone
it can. As the calendering roll, epoxy, poly
Heat resistance of imide, polyamide, polyimide amide, etc.
It is processed with plastic roll or metal roll.
Especially when using double-sided magnetic layers, use metal rolls.
It is preferable. The treatment temperature is preferably 50 ° C. or higher,
More preferably, it is 100 degreeC or more. Line pressure is preferred
Or more than 200kg / cm (≒ 196kN / m)
Preferably 300 kg / cm (≈294 kN / m) or less
Above. [Physical characteristics] of the magnetic recording medium according to the present invention
The saturation magnetic flux density of the magnetic layer is obtained when ferromagnetic metal powder is used.
When using 0.2-0.5T, hexagonal ferrite
0.1 to 0.3T. The coercive force Hc is usually 120 to
400 kA / m, preferably 136-240 k
A / m. Narrower coercive force distribution is preferable. SF
D (switching field distribution
And SFDr are preferably 0.6 or less. In the case of a magnetic disk, the squareness ratio is a two-dimensional run.
In the case of a dam, it is usually 0.55 to 0.67, preferably
0.58 to 0.64, 0.45 for 3D random
~ 0.55 is preferable.
Usually 0.6 or more, preferably 0.7 or more, demagnetizing field correction
When performed, usually 0.7 or more, preferably 0.8 or more
It is. Orientation ratio for both 2D random and 3D random
Is preferably 0.8 or more. 2D random, vertical
The squareness ratio in the direction, Br in the vertical direction and Hc in the vertical direction are
It is preferable to be within 0.1 to 0.5 times the in-plane direction.
Yes. In the case of magnetic tape, the squareness ratio is 0.7 or more, preferably
Is 0.8 or more. The magnetic recording medium of the present invention is worn against the head.
The friction coefficient is in the range of temperature -10 to 40 ° C and humidity 0 to 95%.
In general, the surface hardness is 0.5 or less, preferably 0.3 or less.
The resistance is preferably magnetic surface 10^Four-10¹²Ohm / s
q and the charging position are preferably -500V to + 500V. Magnetism
The elastic modulus at 0.5% elongation of the layer is preferably in each direction in the plane
100-2000Kg / mm²(≒ 980 ~ 19600
N / mm²), The breaking strength is preferably 10 to 70 kg /
mm²(≒ 98 ~ 686N / mm²), Bullets on magnetic recording media
The nature ratio is preferably 100 to 1500 kg / g in each direction in the plane.
mm²(≒ 980 ~ 14700N / mm²)
Preferably any temperature below 0.5% and below 100 ° C
The thermal contraction rate at is preferably 1% or less, more preferably
0.5% or less, most preferably 0.1% or less
The Glass transition temperature of magnetic layer (dynamic measured at 110 Hz
(Maximum point of loss elastic modulus in dynamic viscoelasticity measurement) is 50 ° C. or more and 12
0 ° C or less is preferable, and that of the lower layer is preferably 0 ° C to 100 ° C.
Good. Loss modulus is 1 × 10 ^Three~ 8x10^FourN / cm²
The loss tangent is preferably 0.2 or less.
Preferably there is. If the loss tangent is too large, adhesion failure
Is likely to occur. These thermal and mechanical properties are
It is preferable that each direction is substantially equal within 10%. Magnetism
The residual solvent contained in the active layer is preferably 100 mg / m
²Or less, more preferably 10 mg / m²It is as follows. Painting
The porosity of the fabric layer is preferably 30 volumes for both the lower layer and the upper layer.
The amount is not more than%, more preferably not more than 20% by volume. Sky
Smaller porosity is preferable to achieve high output,
Depending on the purpose, it may be better to secure a certain value.
For example, it is not available for disc media where repeated use is important.
Larger porosity is often preferred for running durability. The center surface average surface roughness Ra of the magnetic layer is WYC.
About 250μm × 250μ using TOPO-3D manufactured by O company
Preferably measured in the area of m, 4.0 nm or less, more preferred
Preferably 3.8 nm or less, particularly preferably 3.5 nm or less.
is there. The maximum height Rmax of the magnetic layer is 0.5 μm or less.
The point average roughness Rz is 0.3 μm or less, and the center plane height Rp is
0.3 μm or less, the central plane valley depth Rv is 0.3 μm or less,
Center plane area ratio Sr is 20% or more and 80% or less, average wavelength
λa is preferably 5 μm or more and 300 μm or less. Magnetic layer
Surface protrusions of 0.01-1 μm in size 0-2
It can be set arbitrarily within the range of 000.
Therefore, it is preferable to optimize the electromagnetic conversion characteristics and friction coefficient.
Good. These are the surface properties of the support filler.
Particle size and amount of powder added to trawl and magnetic layer, calendar
-Easily controlled by the surface shape of the roll
be able to. Curling is preferably within ± 3mm
That's right. Nonmagnetic layer and magnetic layer in the magnetic recording medium of the present invention
Depending on the purpose, the nonmagnetic layer and the magnetic layer
It is easily estimated that the physical properties can be changed.
It is. For example, increase the elastic modulus of the magnetic layer to improve running durability
The elastic modulus of the nonmagnetic layer is lower than that of the magnetic layer.
To improve the contact of the magnetic recording medium with the head.
is there. [0096] EXAMPLES Specific examples of the present invention will be described below.
The present invention should not be limited to this.   Making magnetic tape Comparative Example 1 <Creation of paint> Magnetic layer paint 100 parts of ferromagnetic metal powder   Composition: Co / Fe = 21 atomic%, Al / Fe = 7 atomic%, Y / Fe = 5 atomic%   Average long axis length: 0.06 μm, average needle ratio: 6   Hc: 2310 Oe (185 kA / m), σs: 137 A · m²/ Kg 12 parts of vinyl chloride copolymer MR110 (manufactured by Nippon Zeon) Polyurethane resin UR8200 (Toyobo Co., Ltd.) 3 parts α-Alumina HIT55 (Sumitomo Chemical Co., Ltd.) 2 parts Carbon black # 55 (Asahi Carbon Co., Ltd.) 1 part Butyl stearate 1 part Stearic acid 5 parts 100 parts of methyl ethyl ketone 20 parts of cyclohexanone 60 parts of toluene [0097] Non-magnetic paint Nonmagnetic powder TiO₂80 parts of crystalline rutile   Average particle size: 0.035 μm, S_BET: 40m²/ G, pH: 7, TiO₂Contains 90% or more, DBP oil absorption 27-38ml / 100g, Al on the surface₂O_ThreeParticle 8% by mass based on the whole Carbon black 20 parts   Conductex SC-U (manufactured by Colombian Carbon) 12 parts of vinyl chloride copolymer MR110 (manufactured by Nippon Zeon) Polyurethane resin UR8200 (Toyobo Co., Ltd.) 5 parts Phenylphosphonic acid 4 parts Butyl stearate 1 part Stearic acid 3 parts 250 parts of methyl ethyl ketone / cyclohexanone (8/2 mixed solvent) About the above-mentioned paint, each component is mixed with a kneader.
After kneading, it was dispersed for 4 hours using a sand mill.
Applying polyisocyanate to the resulting dispersion with a nonmagnetic layer
Add 2.5 parts to the solution and 3 parts to the magnetic layer coating solution.
Add 40 parts of cyclohexanone to each and add 1 μm
Filtered with a filter having an average pore size, non-magnetic layer
Prepare coating solution for forming and magnetic layer respectively.
It was. The resulting non-magnetic layer coating solution has a lower layer thickness after drying.
Immediately after that, magnetism is formed on it so that it becomes 1.7 μm.
The thickness is 4.4 μm so that the layer thickness is 0.15 μm.
Aramid support having an average surface roughness of 7.0 nm
(Product name: Mikutron) Simultaneous multi-layer coating,
It has a magnetic force of 0.6T while both layers are still wet.
With a cobalt magnet and a solenoid with a magnetic force of 0.6T
Oriented. After drying, it consists only of metal rolls7
200 m / mi per minute at a temperature of 85 ° C. with a stage calendar
n. And then back layer with a thickness of 0.5 μm
(Carbon black average particle size: 17 nm 10
0 parts, calcium carbonate average particle size: 40 nm 8
0 part, α alumina Average particle size: 200 nm 5 parts
Nitrocellulose resin, polyurethane resin, polyiso
Dispersed in cyanate). Slip to 3.8mm width
Equipped with a slitting device for feeding and winding
Nonwoven fabric and razor blades hit the magnetic surface on the device
Attach the magnetic layer with a tape cleaning device.
The surface was cleaned to obtain a tape sample. Comparative Example 2 In Comparative Example 1, a smooth coating is applied to one surface of the aramid support.
Thickness of the coating solution for the fabric layer (P1: listed in Table 1) is 0.05 μm
After coating and drying to form a smooth coating layer
A nonmagnetic layer and a magnetic layer were formed in the same manner as in Comparative Example 1.
A tape sample was obtained in the same manner as in Comparative Example 1. Examples 1 to 5 and Comparative Examples 3 to 6 In Comparative Example 2, the coating solution for smooth coating layer shown in Table 1 is displayed.
The same as Comparative Example 2 except that the type and thickness described in 2 were changed.
In this way, a tape sample was obtained. Example 7 In Example 3, the coating solution for the smooth coating layer (P7: Table 1)
After the formation of a smooth coating layer, 5Mrad
Example 3 except that a smooth coating layer was formed by irradiating a child wire
In the same manner, a tape sample was obtained. Example 8 In Example 3, the coating solution for the smooth coating layer (P8: Table 1)
To 50 mJ / cm after forming a smooth coating layer.
²Except that the smooth coating layer was formed by irradiating
A tape sample was obtained in the same manner as in Example 3. [0103] [Table 1]In Table 1, the materials are as follows. Material A: Water-soluble polyamide resin (manufactured by Toray Industries, Inc.
Nylon A-90 ", number average molecular weight: 66000) Material B: Copolyester resin (Fuji Photo Film
"STAFIX" Material C: Dioxide of ethylene oxide modified bisphenol A
Acrylate (“BP-4EA” manufactured by Kyoeisha Chemical Co., Ltd.) Material D: 95 parts by mass of Material B and benzyldimethylketer
Le ("Irgacure 65" manufactured by Ciba Specialty)
1 ") 5 parts by weight of mixture Comparative Example 7 Other than changing the magnetic paint to the following in Comparative Example 1
Obtained a tape sample in the same manner as in Comparative Example 1. Non-magnetic
The coating liquid for the adhesive layer is the same as in Comparative Example 1. Magnetic paint 100 parts of barium ferrite magnetic powder   Composition: Ba / Zn / Co / Nb = 1 / 1.0 / 0.5 / 0.4 (molar ratio) 6 parts of vinyl chloride copolymer MR555 (manufactured by Nippon Zeon) Polyurethane resin UR8200 (Toyobo Co., Ltd.) 3 parts α-Alumina HIT55 (Sumitomo Chemical Co., Ltd.) 2 parts Carbon black 5 parts   # 55 (Asahi Carbon Co., Ltd.) Butyl stearate 1 part Stearic acid 2 parts 125 parts of methyl ethyl ketone   125 parts of cyclohexanone Comparative Example 8 In Comparative Example 7, smooth coating was applied to one surface of the aramid support.
Thickness of the coating solution for the fabric layer (P1: listed in Table 1) is 0.05 μm
After coating and drying to form a smooth coating layer
A nonmagnetic layer and a magnetic layer were formed in the same manner as in Comparative Example 7.
A tape sample was obtained in the same manner as in Comparative Example 7. Examples 7-12, Comparative Examples 9-12 In Comparative Example 8, the coating liquid for smooth coating layer described in Table 1 is displayed.
3. The same as Comparative Example 8 except that the type and thickness described in 3 were changed.
In this way, a tape sample was obtained. Example 15 In Example 11, the coating solution for the smooth coating layer (P7: Table
1), and after forming a smooth coating layer,
Example except that a smooth coating layer was formed by irradiation with an electron beam
In the same manner as in No. 11, a tape sample was obtained. Example 16 In Example 11, the coating solution for the smooth coating layer (P8: Table
1) and after forming a smooth coating layer, 50 mJ / c
m²Except that the smooth coating layer was formed by irradiating
A tape sample was obtained in the same manner as in Example 11. Comparative Example 13 Comparative Example 1 except that the nonmagnetic layer was not provided.
A tape sample was obtained in the same manner as in Example 1. Example 17 Example 2 except that the nonmagnetic layer was not provided in Example 2.
A tape sample was obtained in the same manner as in No. 2. Comparative Example 14 In Comparative Example 1, the nonmagnetic layer and the magnetic layer were wet-on
Similar to Comparative Example 1 except that it was provided by the dry (W / D) method
Thus, a tape sample was obtained. Example 18 In Example 2, the nonmagnetic layer and the magnetic layer were wet-on.
Same as Example 2 except that it was provided by dry (W / D) method
Thus, a tape sample was obtained. [0113]   Disc creation Magnetic paint 100 parts of barium ferrite magnetic powder   Composition: Ba / Zn / Co / Nb = 1 / 0.7 / 0.1 / 0.3 (molar ratio) Vinyl chloride copolymer MR555 (manufactured by Nippon Zeon Co., Ltd.) 5 parts Polyurethane resin UR8200 (Toyobo Co., Ltd.) 3 parts α Alumina HIT55 (Sumitomo Chemical Co., Ltd.) 10 parts Carbon black # 55 (Asahi Carbon Co., Ltd.) 1 part Phenylphosphonic acid 2 parts Butyl stearate 10 parts 5 parts butoxyethyl stearate Isohexadecyl stearate 3 parts Stearic acid 2 parts 125 parts of methyl ethyl ketone 125 parts of cyclohexanone [0114] Non-magnetic paint Nonmagnetic powder TiO₂80 parts of crystalline rutile   Average particle size: 0.035 μm, S_BET: 40m²/ G, pH: 7, TiO₂Contains 90% or more, DBP oil absorption 27-38ml / 100g, Al on the surface₂O_ThreeParticle 8% by mass based on the whole Carbon black 20 parts   Conductex SC-U (manufactured by Colombian Carbon) 12 parts of vinyl chloride copolymer MR110 (manufactured by Nippon Zeon) Polyurethane resin UR8200 (Toyobo Co., Ltd.) 5 parts Phenylphosphonic acid 4 parts Butyl stearate 10 parts 5 parts butoxyethyl stearate Isohexadecyl stearate 2 parts Stearic acid 3 parts 250 parts of methyl ethyl ketone / cyclohexanone (8/2 mixed solvent) For each of the above paints, the components are
After kneading with kneader, use sand mill for 4 hours
Scattered. Polyisocyanate is non-magnetic to the resulting dispersion.
10 parts for the coating liquid for the magnetic layer and 10 parts for the coating liquid for the magnetic layer
In addition, add 40 parts of cyclohexanone to each.
Filter using a filter with an average pore size of 1 μm
Coating liquid for forming the nonmagnetic layer and the magnetic layer
Each was prepared. Comparative Example 15 The obtained magnetic layer coating solution was dried to a thickness of 0.2 μm.
Thus, the thickness of 62 μm and the center surface average surface roughness is 7.
Coating on 0 nm polyethylene terephthalate support
While in the wet state, frequency 50Hz, magnetic field
Two magnets with a strength of 25 mT, frequency of 50 Hz, and 12 mT
Random orientation by passing through the field strength AC magnetic field generator
After processing, after drying, use a 7-stage calendar at a temperature of 90 ° C.
Processing is performed at a linear pressure of 300 kg / cm (294 kN / m).
The disc medium is punched to 3.7 mm and subjected to surface polishing.
Got the body. Example 19 In Comparative Example 15, for the smooth coating layer on one side of the support
The coating solution (P1: listed in Table 1) has a thickness of 0.3 μm
After smooth coating, drying and smoothing
The magnetic layer was formed on the coating layer in the same manner as in Comparative Example 15, except that
A disk sample was obtained in the same manner as in Comparative Example 15. Comparative Example 16 The obtained non-magnetic layer coating solution with a thickness of 62 μm and a center plane average table
Polyethylene terephthalate support with a surface roughness of 7.0 nm
Apply and dry on the body so that the thickness after drying is 1.5μm
The thickness of the magnetic layer is 0.15 μm on the obtained nonmagnetic layer.
Apply the magnetic layer coating solution so that
While the magnetic layer is still wet, as in Comparative Example 15.
Random orientation treatment was performed, and in the same manner as Comparative Example 15.
Thus, a disk sample was obtained. Example 20 In Comparative Example 16, Example 19 and one side of the support were
Similarly, after applying and drying the smooth coating layer, do not wind it up.
A nonmagnetic layer on the smooth coating layer formed in the same manner as in Comparative Example 16.
The magnetic layer was formed in the same manner as in Comparative Example 16, except that
A sample was obtained. Comparative Example 17 The obtained non-magnetic layer coating solution has a thickness after drying of 1.5 μm.
Furthermore, immediately after that, the thickness of the magnetic layer on it is
Thickness using magnetic layer coating solution to 0.15 μm
Polyethylene with 62 μm and average surface roughness of 7.0 nm
Apply simultaneous multilayer coating on the terephthalate support.
Same as Comparative Example 15 while both layers are still wet
Random orientation treatment was performed, and the same as in Comparative Example 15
Thus, a disk medium was obtained. Example 21 In Comparative Example 17, Example 19 and one side of the support were
Similarly, after applying and drying the smooth coating layer, do not wind it up.
A nonmagnetic layer on the smooth coating layer formed in the same manner as in Comparative Example 17.
And the magnetic layer was formed in the same manner as in Comparative Example 17,
A sample was obtained. Computer tapes and magnets created above
The performance of each disc is evaluated by the following measurement method.
It was. Measuring method (1) CN ratio (tape): recording head (MIG, gap)
0.15μm, 1.8T) and MR head for playback
Measurement was performed by attaching to a tester. Head-media phase
Speed vs. 1-3m / min, noise measured modulation noise.
The surface recording density is 0.57 Gbit / inch.²(G
Rack pitch: 6.8 μm, bit length: 0.165 μm
m). (2) SN ratio (disk): recording head [MIG (Me
tal in Gap)], gap 0.15 μm,
1.8T) and MR head for playback on a spin stand
It was attached and measured. Rotation speed 2500 ~ 3500rpm, half
Diameter 30mm, noise is DC noise. The surface recording density is
1 Gbit / inch²(Track pitch: 1 μm, video
Length: 0.03 μm). (3) The smooth coating layer PN (20 nm or more) is digital
Nanoscope 3 (AFM: Atomic Force)
Using a microscope, use a SiN probe with a square pyramid with a ridge angle of 70 °.
Use 30μm square angle (900μm²), Protrusion
Was measured. (4) Elution amount of smooth coating layer: methyl ethyl ketone (ME
Elution amount to K) / cyclohexanone mixed solution (1: 1)
Asked. Tables 2 to 4 show the magnetic tape evaluation results, and Table 5 shows the results.
The evaluation results of the magnetic disk are shown. [0119] [Table 2] [0120] [Table 3] [0121] [Table 4][0122] [Table 5] From Tables 2-5, the comparative example which does not satisfy the requirements of a smooth coating layer
Is inferior in CN ratio or SN ratio as compared with the examples. [0123] The present invention provides a smooth coating on the support of a magnetic recording medium.
Providing a fabric layer improves the surface properties of the magnetic layer and
Low cost and high density with improved CN ratio or SN ratio
A magnetic recording medium can be provided.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Hashimoto             2-1-12 Ogimachi, Odawara-shi, Kanagawa Prefecture             Shishi Photo Film Co., Ltd. F-term (reference) 5D006 CB07 CB08 EA01

Claims (1)

1. A magnetic recording medium in which a magnetic layer is formed on a support, and a thickness of 0.10 to 1 μm and a surface roughness on at least one surface of the support. A magnetic recording medium is provided with a smooth coating layer having a thickness of 5 nm or less and 20 protrusions having a height of 20 nm or more measured by an atomic force microscope (AFM) / 900 μm ² or less.