JPH10149536A - Magnetic recording method and cleaning tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deposition of a burnt matter on a magnetic head even with longer sliding time or faster scanning speed, to suppress the spacing loss and to prevent increasing of the error rate by incorporating a preventing agent against burning containing a polyacid compd. into a magnetic recording medium. SOLUTION: This medium is produced by forming a magnetic layer on a nonmagnetic base body and the medium contains a preventing agent against burning which contains a polyacid compd. expressed by formula I and formula II. In the formula I and the formula II, R<1> , R<2> are selected from alkylene groups, alkyleneoxy groups, phenylene group or combination of these having substituents of alkyl groups with substituents of hydrogen atoms, halogen atoms, hydroxyl groups or nitro groups, or aryl groups, heteroaromatic groups, X<1> to X<6> are selected from COOH, COOM, PO3 H2 , etc., wherein M in an alkali metal. Thereby, the complexing reaction is caused between the metal oxide produced on the surface of a magnetic head and the polyacid compd. to produce a complex which easily drops from the magnetic head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a magnetic recording medium capable of preventing a substance adhering to a magnetic head and a cleaning tape for removing the substance adhering to the magnetic head.

[0002]

2. Description of the Related Art In the field of magnetic recording, in particular, in a data cartridge for backing up a hard disk, a digital video recorder, and the like, there is a demand for long-time recording along with higher-capacity recording. Conventionally, this long-time recording has been dealt with by increasing the length of the tape by reducing the thickness of the tape, or by increasing the length of the tape by changing the cassette shell or the like.

In the above-mentioned data cartridge, recording and reproduction by a helical scan system is generally applied. However, in the helical scan method, since the magnetic layer surface and the magnetic head slide at high speed, the temperature of the magnetic head surface becomes high during running of the magnetic tape, so that seizure tends to be easily generated on the surface of the magnetic head. If the sliding time is increased or the scanning speed is increased in association with long-time recording, a burn-in product is more easily generated on the surface of the magnetic head.

Particularly, in an environment such as high temperature and low humidity, the polishing power of the magnetic tape is reduced. Therefore, when a metal oxide or the like generated tribologically causes seizure, the seized material is not polished and the magnetic head is not polished. Accumulate on the surface. Then, a gap (spacing) occurs between the magnetic tape and the magnetic head due to the accumulated seizures and the like, causing a problem that a predetermined signal output cannot be obtained.

At present, in order to improve the electromagnetic conversion characteristics and reduce the spacing loss, the surface properties of the tape are improved by super calendar treatment or the like, and the friction between the magnetic tape and the magnetic head is further increased. Tend to be. However, this tendency promotes the generation of burn-in on the surface of the magnetic head described above.

Attempts have been made to add a reducing agent, such as an ascorbic acid derivative, to a magnetic tape as an antioxidant in order to prevent seizures on the magnetic head, or to hold the magnetic tape in order to reduce friction. Attempts have been made to increase the amount of lubricant. However, even if the magnetic tape holds antioxidants and lubricants,
Once produced, the burn-in cannot be removed.

[0007] On the other hand, in order to remove burn-in products once generated, a method of using a cleaning tape for physically polishing a magnetic head or a method of mounting a cleaning roll mechanism for sequentially polishing a magnetic head in a system has been studied. For example, Japanese Patent Application Laid-Open No. 57-208626
Japanese Patent Application Laid-Open Publication No. H11-15064 discloses that α-Al ₂ O ₃ powder having a Mohs hardness of 8 or more or Cr ₂ O ₃
A cleaning tape has been proposed in which abrasive particles such as powder are bound by a binder resin.

[0008] However, the abrasive particles used in such a physical method have an extremely high hardness and are excellent in abrasiveness, but when removing seizures from the magnetic head, the magnetic head itself is worn and damaged. I will. Especially 8
In magnetic heads used for recording and reproducing mm video tapes and digital video tapes, the head gap is 0.3μ.
m or less, and slides at a high speed with respect to the tape, so that damage is apt to occur even by a small impact, and abrasion and damage by the abrasive particles as described above are liable to occur.

On the other hand, Japanese Patent Publication No. 8-001695 proposes to control wear of a magnetic head by controlling the particle size of abrasive particles. However, no matter how much the particle size of the abrasive particles is controlled, wear and damage to the magnetic head cannot be avoided as long as α-Al ₂ O ₃ powder or Cr ₂ O ₃ powder having high hardness is used.

[0010]

Although various measures have been taken against the burn-in substance adhering to the magnetic head from the medium side or the cleaning tape side, all of them are satisfactory. However, further investigation is desired.

Therefore, the present invention has been proposed in view of such a conventional situation.
It is an object of the present invention to provide a magnetic recording medium which does not generate burn-in on a magnetic head even if the sliding time is increased or the scanning speed is increased, suppresses a spacing loss, and prevents an increase in an error rate. It is another object of the present invention to provide a cleaning tape capable of removing burn-in substances attached to the magnetic head without causing wear and damage to the head.

[0012]

SUMMARY OF THE INVENTION The magnetic recording medium according to the present invention achieves the above-mentioned object and comprises at least a magnetic layer formed on a non-magnetic support. Hereinafter, the ligand is simply referred to as a “ligand”.)

[0013] The cleaning tape according to the present invention is characterized in that an anti-seizing agent containing a polyacid compound is held on a support.

First, examples of the ligand used in the magnetic recording medium according to the present invention include those represented by at least one of the following chemical formulas (9) and (10).

[0015]

Embedded image

[0016]

Embedded image

Since the above-mentioned ligand has the ability to form a complex with a metal atom, when it is held on a magnetic recording medium, a complex-forming reaction occurs with the metal oxide formed on the surface of the magnetic head, The complex is easily desorbed from the surface of the magnetic head. Thus, the metal oxide can be removed from the magnetic head. Therefore, when the present invention is applied, burn-in does not accumulate on the magnetic head, so that a decrease in output due to a spacing loss is prevented and an error rate can be suppressed.

The configuration of the magnetic recording medium to which the present invention is applied is not particularly limited, and may have a so-called coating type magnetic layer or a vapor deposition type magnetic layer. The former, that is, when the magnetic layer is formed by applying a magnetic paint mainly composed of a magnetic powder and a binder,
The anti-seizure agent may be applied to the surface of the magnetic layer, or may be internally added to the magnetic layer.

The anti-seizure agent held by the coating type magnetic layer preferably contains a titanate coupling agent and a carboxylic acid together with the ligand.

That is, since the ligand has the ability to form a complex with a metal atom, it also coordinates and adsorbs to the magnetic powder contained in the magnetic layer. When the ligand is coordinated and adsorbed to the magnetic powder, the ligand cannot contribute to the complex formation reaction with the metal oxide attached to the magnetic head, so that the effect of the ligand to prevent accumulation of the metal oxide is impaired. It is.

When a titanate coupling agent or a carboxylic acid is present, these compounds are easily adsorbed on the surface of the magnetic powder and hinder the ligand from coordinating and adsorbing on the magnetic powder. Therefore, the ligand effectively contributes to complex formation with the metal oxide attached to the magnetic head.

On the other hand, when the magnetic recording medium has a so-called evaporation type magnetic layer, that is, when the magnetic layer is a metal magnetic thin film, a carbon film is formed on the magnetic layer, and Preferably, an anti-seizure agent is applied.

When the anti-seizure agent is applied to the surface of the carbon film as described above, the anti-seizure agent may be added to the above-mentioned ligand together with the above-mentioned ligands by the following formulas (M) to
When a compound containing phosphorus represented by at least one selected from Formula 4 (Formula (P)) is contained, the effect of preventing the accumulation of seizures is further improved.

[0024]

Embedded image

[0025]

Embedded image

[0026]

Embedded image

[0027]

Embedded image

The anti-seizure agent is held on the magnetic layer as described above, or alternatively, instead of holding the anti-seizure agent on the magnetic layer, the non-magnetic support is opposite to the surface on which the magnetic layer is formed. The anti-seizure agent may be held on the back coat layer formed on the surface of the substrate. Also in this case, the anti-seizure agent may be applied to the surface of the back coat layer or may be internally added to the back coat layer. Since the magnetic tape is usually wound and used in a cassette, when the above-described anti-seizure agent is held in the back coat layer, the anti-seizure agent is transferred to the sliding surface side with the magnetic head. You. Therefore, even when the anti-seizure agent is held on the back coat layer side, the same effect as when the anti-seizure agent is held on the magnetic layer side can be obtained.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the magnetic recording medium according to the present invention will be described below. The magnetic recording medium according to the present invention is obtained by forming at least a magnetic layer on a non-magnetic support, and is characterized in that an anti-seizure agent containing a polyacid compound (ligand) is held. Is what you do.

The ligand used herein is at least one of the following polyacid compounds represented by the following chemical formulas (15) and (16).

[0031]

Embedded image

[0032]

Embedded image

When the chemical formula 15 is a polycarbonyl, that is, when the substituents X ^{1 to} X ⁴ are COOH or COOM, examples of such a compound include ethylenediaminetetraacetic acid (formula (A)). In addition to derivatives of EDTA), those represented by Chemical Formula 18 (Formula (B)), stilbenefluor blue derivatives represented by Chemical Formula 19 (Formula (C)), and methyls represented by Chemical Formula 20 (Formula (D)) A thymol blue derivative; a methyl xylenol blue derivative represented by the following formula (21); and a xylenol orange derivative represented by the following formula (22).

[0034]

Embedded image

[0035]

Embedded image

[0036]

Embedded image

[0037]

Embedded image

[0038]

Embedded image

[0039]

Embedded image

When the chemical formula 15 is polyphosphoric acid, that is, when the substituents X ^{1 to} X ⁴ are PO ₃ H ₂ or PO ₃ HM, such a compound is represented by the following formula (G). And those represented by Chemical Formula 24 (formula (H)).

[0041]

Embedded image

[0042]

Embedded image

Further, the substituents X ^{1 to} X ⁴ in Chemical formula 15
Is CH ₂ COOH, examples of such a compound include those represented by Formula 25 (Formula (I)).

[0044]

Embedded image

On the other hand, when Chemical Formula 16 is polycarbonyl, that is, when the substituents X ⁵ and X ⁶ are COOH or COOM, such compounds include Chemical Formula 26 (Formula (J)) and Chemical Formula 27 ( In the case where Chemical Formula 16 is polyphosphoric acid, that is, when the substituents X ⁵ and X ⁶ are PO ₃ H ₂ or PO ₃ HM, such a compound is 28 (formula (L)) and 29 (formula (M)). When the substituents X ⁵ and X ⁶ in Chemical Formula 16 are CH ₂ COOH, such compounds include those represented by Chemical Formula 30 (Formula (N)).

[0046]

Embedded image

[0047]

Embedded image

[0048]

Embedded image

[0049]

Embedded image

[0050]

Embedded image

As described above, there are various kinds of ligands contained in the anti-seizure agent. These may be used alone or in combination of a plurality of kinds. Is also good.

The configuration of the magnetic recording medium to which the present invention is applied is not particularly limited, and it may have a so-called coating type magnetic layer or may have a deposition type magnetic layer. The former, that is, when the magnetic layer is formed by applying a magnetic paint mainly composed of a magnetic powder and a binder, the anti-seizing agent may be applied to the surface of the magnetic layer,
It may be internally added to the magnetic layer. Further, when the ligand is internally added to the coating type magnetic layer or the back coat layer, the ligand may be present in a form chemically bonded to the binder.

When the anti-seizure agent is applied to the surface of the magnetic layer, the applied amount is 1 to 1 m ² of the magnetic layer.
It is preferably 0 mg to 10 g. When the anti-seizure agent is internally added to the magnetic layer, the amount thereof is preferably 0.3 to 20 parts by weight based on 100 parts by weight of the magnetic powder. If the application amount or the addition amount of the anti-seizure agent is less than the above range, the effect of suppressing the seizure of the magnetic head becomes insufficient, and if it is more than the above range, the runnability of the magnetic recording medium deteriorates. .

When a ligand is internally added to the coating type magnetic layer, a titanate coupling agent or a carboxylic acid may be used in combination for the purpose of preventing adsorption of the ligand to the magnetic powder. That is, since the ligand has the ability to form a complex with a metal atom, it also coordinates and adsorbs to the magnetic powder contained in the magnetic layer. When the ligand is coordinated and adsorbed on the magnetic powder, the ligand cannot contribute to the complex formation reaction with the metal oxide attached to the magnetic head, so that the effect of removing the metal oxide of the ligand is impaired.

Here, when a titanate-based coupling agent or a carboxylic acid is present, these compounds are easily adsorbed on the surface of the magnetic powder, so that the ligand is prevented from coordinating and adsorbing on the magnetic powder. Therefore, the ligand effectively contributes to complex formation with the metal oxide of the magnetic head.

As the titanate-based coupling agent, it is desirable to use one into which at least one of an amino group, a phosphate ester group, a carboxylate ester, an acyl group, a carbonyl group, a hydroxyl group and an alkyl group has been introduced. Specific examples include those represented by Chemical Formulas 31 to 35.
Such a titanate-based coupling agent acts to suppress the coordination and adsorption of the ligand to the magnetic powder and to enhance the dispersibility of the magnetic powder.

[0057]

Embedded image

[0058]

Embedded image

[0059]

Embedded image

[0060]

Embedded image

[0061]

Embedded image

These titanate coupling agents may be used alone or in combination of two or more.

In order to internally add a titanate-based coupling agent to a magnetic layer, a titanate-based coupling agent may be added to the magnetic coating at the stage of preparing the coating. However, the titanate coupling agent needs to be added before the ligand. That is, a titanate coupling agent is mixed with a magnetic powder, a binder and an organic solvent, kneaded and dispersed, and then a ligand is added. Alternatively, the magnetic powder is previously subjected to a pretreatment with a titanate coupling agent, and the magnetic powder thus treated is kneaded and dispersed together with a binder and an organic solvent, and then a ligand is added.

The amount of the titanate coupling agent added to the magnetic layer is preferably 0.5 to 10 parts by weight based on 100 parts by weight of the ferromagnetic powder. When the amount of the titanate-based coupling agent is smaller than this range, the adsorption of the ligand to the magnetic powder cannot be sufficiently suppressed, and the effect of preventing the seizure by the ligand is insufficient. In addition, the dispersibility of the magnetic powder cannot be sufficiently improved. Conversely, when the amount of the titanate-based coupling agent is larger than this range, a large number of functional groups of the titanate-based coupling agent remain unreacted with the binder or the magnetic powder,
These unreacted functional groups interact with each other to reduce the dispersibility of the magnetic powder. A more preferable range of the internal addition amount is 1.0 to 5.0 parts by weight based on 100 parts by weight of the ferromagnetic powder.

The carboxylic acid may have a pKa of 6 or less. Formic acid, acetic acid, propionic acid, acetic acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid Acids, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachinic acid, saturated fatty acids such as pehenic acid, acrylic acid, crotonic acid, isocrotonic acid, undecylenic acid, oleic acid, elaidic acid Unsaturated fatty acids such as cetreic acid, erucic acid, pracidic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid Saturated aliphatic dicarboxylic acids such as cephasic acid, maleic acid, fumaric acid Aliphatic unsaturated dicarboxylic acids like phthalic acid, isophthalic acid, aromatic dicarboxylic acids such as terephthalic acid, and tricarboxylic acids such as citric acid. In particular, oleic acid and myristic acid are practical because they also exert a lubricating effect.

The amount of the carboxylic acid added to the magnetic layer is preferably 1 to 30 parts by weight based on 100 parts by weight of the magnetic powder.

These titanate-based coupling agents and carboxylic acids are not limited to the case where the anti-seizure agent is internally added to the coating type magnetic layer, but may be used to prevent the surface of the coating type magnetic layer or the vapor deposition type magnetic layer from sticking. It may be used in combination when applying the agent. However, since the adsorption of the ligand to the magnetic powder becomes the most problematic when the ligand is internally added to the magnetic layer, it is effective to use the ligand together with such internal addition.

On the other hand, when the magnetic recording medium has a so-called evaporation type magnetic layer, that is, when the magnetic layer is a metal magnetic thin film, a carbon film is formed on the magnetic layer, and Preferably, an anti-seizure agent is applied. In this case, the application amount of the anti-seizure agent
The amount may be the same as the amount applied to the coating type magnetic layer described above.

When the anti-seizure agent is applied to the surface of the carbon film as described above, the anti-seizure agent may be added to the above-mentioned ligand together with the above-mentioned ligands by the following formulas (Formula (O)) to Formula 39 (Formula (R)). ) May be contained.

[0070]

Embedded image

[0071]

Embedded image

[0072]

Embedded image

[0073]

Embedded image

The phosphorus-containing compound may be held on the coating type magnetic layer, but it is more practical to apply the compound on the surface of the evaporation type magnetic layer.

In addition to holding the anti-seizure agent in the magnetic layer as described above, or instead of holding the anti-seizure agent in the magnetic layer, the non-magnetic support is opposite to the surface on which the magnetic layer is formed. The anti-seizure agent may be held on the back coat layer formed on the surface of the substrate. Also in this case, the anti-seizure agent may be applied to the surface of the back coat layer or may be internally added to the back coat layer. Since the magnetic tape is usually wound and used in a cassette, when the above-described anti-seizure agent is held in the back coat layer, the anti-seizure agent is transferred to the sliding surface side with the magnetic head. You. Therefore, even when the anti-seizure agent is held on the back coat layer side, the same effect as when the anti-seizure agent is held on the magnetic layer side can be obtained. The amount of the anti-seizure agent to be retained may be the same as the amount applied to or internally added to the magnetic layer.

The materials constituting the non-magnetic support and the magnetic layer in the magnetic recording medium to which the present invention is applied are as follows:
Any conventionally known one can be used, and there is no particular limitation.

For example, as the non-magnetic support,
Polyethylene terephthalate, polyethylene-2,6-
Polyesters such as naphthalate, polyolefins such as polypropylene, celluloses such as cellulose triacetate and cellulose diacetate, vinyl-based resins, polyimides, polyamides, polycarbonates, and polymer materials represented by polyphenylene sulfide and the like. It is preferable to use a film. The thickness of such a nonmagnetic support is 1.0 to 100 μm.
m, preferably 2.0 to 70 μm. Note that a metal plate such as an Al alloy plate, a glass plate, or a rigid substrate such as ceramics may be used. In this case, an oxide film such as alumite treatment or a Ni-P film is formed on the substrate surface. The surface may be hardened.

When the magnetic recording medium has a coating type magnetic layer, the magnetic layer is formed by applying a magnetic paint mainly composed of a magnetic powder and a binder. , Γ-Fe ₂ O ₃ , Fe ₃ O ₄ , γ-
Belt compound of Fe ₂ O ₃ and Fe ₃ O ₄ , Co
Containing γ-Fe ₂ O ₃ , Co-containing Fe ₃ O ₄ , Co-containing belt-ride compound of γ-Fe ₂ O ₃ and Fe ₃ O ₄ , CrO ₂ containing one or more metal elements such as Te , Sb, Fe, Bi and the like.

Further, metals such as Fe, Co and Ni, and F
e-Co, Fe-Ni, Fe-Co-Ni, Fe-Co
-B, Fe-Co-Cr-B, Mn-Bi, Mn-A
1, Fe-Co-V, Fe-Al, Fe-Ni-Al,
Fe-Al-P, Fe-Ni-Si-Al, Fe-Ni
-Si-Al-Mn, Fe-Mn-Zn, Fe-Ni-
Zn, Co-Ni, Co-P, Fe-Co-Ni-C
r, alloys such as Fe-Co-Ni-P, and ferromagnetic metal powders such as iron carbide and iron nitride.

Such a ferromagnetic metal powder can be obtained by a method of reducing an oxide, a hydrated oxide, an inorganic salt, an organic acid salt, or the like of the above-described metal element in a gas phase by a reducing gas or a method of performing a wet reduction. Can be obtained by In producing the ferromagnetic metal powder, an appropriate amount of a light metal element such as Al, Si, P, or B may be added for the purpose of preventing sintering during reduction or maintaining the shape.

Further, after the reduction, a method of impregnating and drying with an organic solvent, a method of immersing in an organic solvent and blowing and drying an oxidizing gas, and a method of blowing an oxidizing gas having a controlled partial pressure without using an organic solvent are used. A thin oxide film is formed on the surface to provide oxidation stability. The oxide film formed on the surface is not only the constituent element of the metal or alloy described above,
Al, Si, Ca, Mg, Sr, Ba, B, S, Ti,
Zn, Na, Zr, K, Y, La, Ce, Pr, Nd,
It may contain Sm, Gd, Ge, Sn, Ga and the like.

Further, as the magnetic powder, besides the above oxides and ferromagnetic metal powders, hexagonal plate-like ferrite can be used. Examples of the hexagonal plate-like ferrite include M-type, W-type, Y-type, and Z-type barium ferrite, strontium ferrite, calcium ferrite, lead ferrite, and the like. Ti, Co-Ti-Zn, Co-Ti-N
b, Co-Ti-Zn-Nb, Cu-Zr, Ni-Ti
The addition of such as can also be used.

These magnetic powders may be used alone or in combination of two or more.

The size of these magnetic powders is desirably set as follows.

[0085] First, the specific surface area is preferably from 30~80m ² / g, and more preferably 40~70m ² / g. The magnetic powder having a specific surface area in this range has very fine particles, and by using such a fine magnetic powder, high-density recording becomes possible and noise is reduced.

In particular, when the magnetic powder is acicular particles, the major axis length is 0.05 to 0.50 μm and the axial ratio is 2 to 1.
It is preferably 5. When the major axis length is less than 0.05 μm, it becomes difficult to disperse the magnetic powder in the paint, and when the major axis length exceeds 0.50 μm, noise may increase. On the other hand, when the axial ratio is less than 2, the orientation of the magnetic powder is reduced, and the output is reduced. Conversely, when the axial ratio exceeds 15, the short-wavelength signal output decreases.

On the other hand, when the magnetic powder is plate-like ferrite, the plate diameter is 0.01 to 0.5 μm and the plate thickness is 0.001 to
It is preferably 0.2 μm.

The major axis length, axial ratio, plate diameter, and plate thickness of the magnetic powder shown above were obtained by randomly selecting at least 100 samples from a transmission electron micrograph and calculating the average value. is there.

As the binder contained in the magnetic layer of the present invention, known thermoplastic resins, thermosetting resins, reactive resins and the like conventionally used as binders for magnetic recording media can be used. Those having an average molecular weight of 5,000 to 100,000 are preferred.

Examples of the thermoplastic resin include vinyl chloride, vinyl acetate, vinyl propionate, vinyl alcohol, maleic acid, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, vinylidene chloride, acrylonitrile, methacrylonitrile, styrene, methyl Polymers or copolymers containing styrene, butadiene, ethylene, vinyl acetal, vinyl butyral, vinyl ether, vinyl pyrrolidone, and the like as constituent units are included. Specifically, a vinyl chloride-vinyl acetate copolymer,
Vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, acrylate-acrylonitrile copolymer, acrylate-vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, acrylate -Acrylonitrile copolymer, acrylate-vinylidene chloride copolymer, methacrylate-vinylidene chloride copolymer,
Examples include methacrylate-vinyl chloride copolymer, methacrylate-ethylene copolymer, vinylidene chloride-acrylonitrile copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral, and styrene-butadiene copolymer. Other examples include polyvinyl fluoride, polyamide resins, and cellulose derivatives such as cellulose acetate butyrate, cellulose diacetate, cellulose triacetate, cellulose propionate, and nitrocellulose, polyurethane resins, polyester resins, amino resins, and synthetic rubbers. Can be

Examples of the thermosetting resin or the reactive resin include a phenol resin, an epoxy resin, a polyurethane curable resin, a urea resin, a melamine resin, an alkyd resin, a silicone resin, a polyamine resin, and a urea formaldehyde resin. .

Further, a polar functional group may be introduced into all of these binders for the purpose of improving the dispersibility of the pigment component.

The polar functional groups include -SO ₃ M, -OS
O ₃ M, —COOM, P ＝ O (OM) ₂ (where M represents a hydrogen atom or an alkali metal such as lithium, potassium, and sodium) and the like. Also, -NR
^{1 R 2, -NR 1 R 2} R 3+ X - side chain amine having end groups of or,> NR ¹ R ²⁺ X ^- main-chain amine represented by (wherein, R ^1, R ^2, R ³ represents a hydrogen atom or a hydrocarbon group, and X ⁻ represents a halogen element ion such as fluorine, chlorine, bromine or iodine, an inorganic ion, or an organic ion. Further, polar functional groups include -OH,-
SH, -CN, epoxy group and the like. The amount of the polar functional group contained in the binder is 10 ^-8 to 10 ^-1 mo.
1 / g, preferably 10 ⁻² to 10 ⁻⁶ mol / g.
Is more preferable.

The above-mentioned binders are used for the magnetic layer. These binders may be used alone or in combination of two or more.

The magnetic powder and the binder as described above are dispersed in a solvent to form a magnetic paint.
Ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone; alcohol solvents such as methanol, ethanol, propanol, butanol, and isopropanol; methyl acetate, ethyl acetate, butyl acetate, propyl acetate, ethyl lactate, and ethylene glycol Ester solvents such as acetate, diethylene glycol dimethyl ether, 2-ethoxyethanol, ether solvents such as tetrahydrofuran and dioxane, benzene, toluene, aromatic hydrocarbon solvents such as xylene, methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, Examples thereof include halogenated hydrocarbon solvents such as chlorobenzene and water.

Incidentally, a lubricant, an abrasive, a hardener, a dispersant, an antistatic agent, a rust inhibitor and the like may be added to the magnetic paint as needed. As the dispersant, the lubricant, the antistatic agent and the rust preventive, any conventionally known materials can be used, and there is no particular limitation.

Examples of the lubricant include a solid lubricant such as graphite, molybdenum disulfide, tungsten disulfide, etc.
Monocarboxylic acids having an alkyl chain of 0 to 40, electrolytes of these carboxylic acids, these carboxylic acids and 10 to 10 carbon atoms
It is preferable to use monoesters with 40 alcohols, polyesters of these carboxylic acids with polyhydric alcohols, or amides, amines and alcohols having the above-mentioned alkyl chains. Further, silicon oil, paraffin oil, fluorinated compounds of the above compounds, terpene compounds, oligomers thereof, and the like may be used.

As the polishing agent, aluminum oxide (α,
β, γ), silicon carbide, chromium oxide, iron oxide, corundum, diamond, silicon nitride, titanium carbide, titanium oxide (rutile, anatase), garnet, emery, boron nitride and the like. These abrasives preferably have a Mohs hardness of 4 or more, preferably 5 or more, and a specific gravity of 2 to 6, preferably 3 to 5. The average particle size is 0.5 μm or less, preferably 0.3 μm
m or less is good. The average particle size was obtained by randomly selecting 100 or more samples from a transmission electron microscope photograph and calculating the average value. The addition amount of these abrasives is 20 parts by weight or less based on 100 parts by weight of the ferromagnetic powder.
Preferably, the amount is 10 parts by weight or less.

As the antistatic agent, carbon black is preferably used, and by adding this, the strength of the coating film can be improved.

Further, as the dispersant, various surfactants or various coupling agents can be used.

Examples of the curing agent include alkylene diisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate;
Examples thereof include bifunctional isocyanate compounds such as xylene diisocyanate, naphthalene diisocyanate, and isophorone diisocyanate, or a reaction product of a polymer of these diisocyanates and a polyhydric alcohol. The addition amount of these curing agents is 5 to 80 parts per 100 parts by weight of the binder.
It is preferably used in an amount of 10 parts by weight, more preferably 10 to 50 parts by weight.

To prepare a magnetic paint, the above-mentioned materials are formed into a paint by a kneading step, a mixing step, and a dispersion step. As a dispersing device and a kneading device, a roll mill, a ball mill, a sand mill, an agitator, a kneader, an extruder, a homogenizer, an ultrasonic disperser, and the like are used.

The magnetic coating thus prepared is applied to the non-magnetic support by any method such as spraying or roll coating, and dried to form a magnetic layer. After that, it was led to a calendar device,
The magnetic layer may be subjected to a surface smoothing treatment.

Here, the thickness of the magnetic layer when dried is 0.1%.
To 50 μm, preferably 1.0 to 30 μm. The mixing ratio of the binder to the magnetic powder is 1 to 10 parts by weight, preferably 3 to 9 parts by weight, based on 1 part by weight of the binder. When the amount of the binder is too large, the ratio of the magnetic powder in the magnetic layer becomes relatively small, and the output decreases. In addition, when the magnetic layer repeatedly slides on the magnetic head and various sliding members on the drive, plastic flow easily occurs in the magnetic layer, and the running durability of the medium is reduced. If the amount of the binder is too small, the magnetic layer becomes brittle, and the running durability of the medium decreases.

When such a coating type magnetic layer is provided, a nonmagnetic powder is dispersed in a binder between the magnetic layer and the nonmagnetic support in order to smooth the magnetic layer. Alternatively, a non-magnetic layer (lower layer) may be provided. When the magnetic layer is provided directly on the non-magnetic support, particularly when the thickness of the magnetic layer is small, the surface roughness of the non-magnetic support tends to appear on the surface of the magnetic layer, making it difficult to smooth the surface of the magnetic layer. become. When a non-magnetic layer is provided between the non-magnetic support and the magnetic layer, the thickness is increased between the non-magnetic support and the magnetic layer, so that the surface roughness of the non-magnetic support hardly appears on the magnetic layer surface. As a result, the magnetic layer can be formed on a smooth surface.

As the binder used in the non-magnetic layer, any of those exemplified for the magnetic layer can be used.

The non-magnetic powder includes, for example, α-
Non-magnetic iron oxide such as Fe ₂ O ₃ , goethite, rutile type titanium oxide, anatase type titanium oxide, tin oxide, tungsten oxide, silicon oxide, zinc oxide, chromium oxide, cerium oxide, titanium carbide, BN, α-alumina , Β-alumina, γ-alumina, calcium sulfate, barium sulfate,
Examples include molybdenum disulfide, magnesium carbonate, calcium carbonate, barium carbonate, strontium carbonate, barium titanate, and the like. These non-magnetic powders may be doped with an appropriate amount of impurities depending on the purpose.
The surface may be treated with a compound such as i, Ti, Sn, Sb, or Zr. In addition, one kind of these nonmagnetic powders may be used alone, or a plurality of kinds may be used in combination. The specific surface area of these non-magnetic powders is 30 to 80 m ² / g, and more preferably 40 to 70 m ² / g.
Is more preferable.

The nonmagnetic layer may contain, in addition to these nonmagnetic powders, carbon black such as rubber furnace, pyrolytic carbon, color black, and acetylene black, if necessary. The specific surface area of carbon black is preferably 100 to 400 m ² / g, and the DBP oil absorption is preferably 20 to 200 ml / 100 g.

The specific surface area of carbon black and other non-magnetic powders is set so that the non-magnetic layer is formed on a smooth surface, whereby the magnetic layer is formed on a smooth surface. is there. In carbon black and other non-magnetic powders, the specific surface area within the above-mentioned range means that the particles are fine particles, whereby the non-magnetic layer, and thus the magnetic layer, is formed with a smooth surface. Then, by making the surface of the magnetic layer rough, modulation noise and spacing loss are suppressed, and high electromagnetic conversion characteristics can be obtained.

When the magnetic recording medium has an evaporation type magnetic layer, that is, a magnetic layer made of a metal magnetic thin film, the metal magnetic thin film is made of a ferromagnetic metal material by plating, sputtering, vacuum evaporation or the like. What is necessary is just to form by continuously attaching on a magnetic support. Examples of the metal magnetic thin film include metals such as Fe, Co, and Ni, and Co-Ni.
Alloy, Co-Pt alloy, Co-Pt-Ni alloy,
Fe-Co alloy, Fe-Ni alloy, Fe-Co-N
i-type alloy, Fe-Ni-B-based alloy In-plane magnetization recording type composed of Fe-Co-B-based alloy, Fe-Co-Ni-B-based alloy, and perpendicular magnetization composed of Co-Cr-based alloy A recording type is exemplified.

In the case of a metal magnetic thin film of the in-plane magnetization recording type, Bi, Sb, Pb,
A base layer of a low-melting non-magnetic material such as Sn, Ga, In, Ge, Si, and Ti is formed in advance, and a metal magnetic thin film is formed by vertically depositing or sputtering a metal magnetic material on the base layer. It is good to form. When a metal magnetic material is deposited on the underlayer, the low-melting nonmagnetic material of the underlayer diffuses into the metal magnetic thin film, the orientation of the metal magnetic thin film is eliminated, and in-plane isotropy is secured. And the coercivity is improved.

On such a metal magnetic thin film, a carbon film is formed. In addition, this carbon film may be any of graphite, diamond, and amorphous. As a method for forming the carbon film, a sputtering method is generally used, but any method such as a CVD method may be applied. As the thickness of the carbon film,
The thickness is preferably 2 to 100 nm, particularly 5 to 30 n.
m is preferred.

Further, as described above, the magnetic layer of the non-magnetic support is formed on the magnetic recording medium to which the present invention is applied, for the purpose of improving the running property of the medium, preventing charge and preventing transfer. The back coat layer may be provided on the surface opposite to the surface on which the light is present. This back coat layer is a layer in which a carbon-based fine powder for imparting conductivity to the binder exemplified above with the magnetic paint and an inorganic pigment for controlling surface roughness are dispersed. It is provided to improve the performance.

The powder to be internally added to the back coat layer is, in addition to carbon black, benzoguanamine resin powder, melamine resin powder, epoxy resin powder, polyethylene terephthalate powder, phthalocyanine pigment powder, titanium oxide, and the like. Powder, silicon oxide powder, molybdenum disulfide powder, tungsten disulfide powder, hydrous iron oxide powder, magnesium silicate powder, calcium carbonate powder, aluminum silicate powder, barium sulfate powder, clay powder and the like can be used.

The average primary particle size of these powders is 0.001
It is preferably from μm to 1.0 μm. If it ’s too small,
Poor dispersibility in the paint, there is a possibility that the surface of the back coat layer is too rough, if too large, hard large irregularities are formed on the surface of the back coat layer, and when the magnetic tape is wound, the magnetic layer This unevenness is transferred. Further, such a powder is used in an amount of 25 parts per 100 parts by weight of the resin binder.
It is preferable to add to 150 parts by weight. If the content of the powder is too small, the effect of roughening the surface of the back coat layer becomes insufficient, and if the content is too large, the mechanical properties of the coating film of the back coat layer become weak.

By the application of the present invention, burn-in of the magnetic head is prevented.
Any structure may be used as long as it slides on the magnetic recording medium at the time of recording / reproduction or at the time of starting / stopping the recording / reproduction operation. Specifically, general ferrite head, metal-in-gap (MIG)
Type head, laminated type head, inductive head, magnetoresistive (MR) type head, and the like. In addition, as the material of these magnetic heads, any conventionally known materials can be used.

Next, an embodiment of the cleaning tape according to the present invention will be described.

The cleaning tape according to the present invention is constituted by holding a polyacid compound (ligand) on a support. The cleaning tape is for removing burn-in substances adhered to the magnetic head by running the cleaning tape against the medium sliding surface of the magnetic head.

As the ligand used here, any of the ligands exemplified above as the anti-seizure agent for the magnetic recording medium can be used. That is, the above chemical formulas 15 and 16
At least one of the polyacid compounds represented by Also in this case, the various substituents exemplified above are introduced into these ligands.
And the like. These ligands may be used alone or in combination of two or more.

Since the above-mentioned ligand has a complexing ability with a metal atom, when the cleaning tape holding the ligand is slid against the surface of the magnetic head, the ligand is formed on the surface of the magnetic head. A complex formation reaction occurs with the converted metal oxide to form a complex. This complex is easily detached and removed from the surface of the magnetic head.

As the support for holding the ligand, polyethylene terephthalate, polyethylene naphthalate,
A polymer film made of polyphenylene sulfide, polyamide, polyimide or the like is used. The thickness of the polymer film is preferably from 1.0 to 200 μm, more preferably from 2.0 to 100 μm.

In addition, a so-called nonwoven fabric in which fibers made of these polymers and the like are joined may be used as the support.

The shape of the support is appropriately selected according to the application. For example, a tape-shaped support is used for a cleaning tape for cleaning a magnetic head for a magnetic tape, and a cleaning tape for cleaning a magnetic head for a floppy disk is used for a cleaning tape for cleaning a magnetic head for a magnetic tape. A disk-shaped support is used.

In order to hold the ligand on the support, the ligand is dissolved in a solvent to prepare a cleaning coating, and this cleaning coating is applied on the support.

When the support is a polymer film, the cleaning coating is held as a thin film on the surface of the polymer film. When the support is a nonwoven fabric, the nonwoven fabric is held in a form impregnated with a cleaning paint.

Examples of the solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone and cyclohexanone, alcohol solvents such as methanol, ethanol, propanol, butanol and isopropanol, methyl acetate, ethyl acetate and butyl acetate. And an aromatic solvent such as benzene, toluene and xylene, and water.

A layer composed of a powder component such as carbon black and a binder may be formed on the surface of the support, and a cleaning paint may be applied to the surface of this layer.

Incidentally, the carbon black contained in this layer acts to increase the strength of the coating film in addition to the antistatic effect.

When a cleaning paint is applied, the amount of the ligand applied is preferably 10 mg to 10 g per 1 m ² . If the amount of the ligand is smaller than this range, the effect of removing the burn-in adhered on the magnetic head is insufficient. If the amount of the ligand is larger than this range, the ligand adheres to the surface of the magnetic head, and the running of the tape is hindered.

The cleaning paint may be held on the support in advance, but may be applied to the support immediately before cleaning.

Further, a binder may be mixed with the cleaning paint, and the ligand may be bound to the support by the binder. In this case, the ligand is retained in a form of a binder layer having a certain thickness. It is also preferable that this layer contains a powder component such as carbon black for the purpose of preventing static charge and improving the strength of the coating film.

Examples of the binder include vinyl chloride, vinyl acetate, vinyl propionate, vinyl alcohol, maleic acid, acrylic acid, acrylate, methacrylic acid,
Examples thereof include polymers or copolymers containing methacrylic acid ester, vinylidene chloride, acrylonitrile, methacrylonitrile, styrene, methylstyrene, butadiene, ethylene, vinyl acetal, vinyl butyral, vinyl ether, vinyl pyrrolidone, and the like as constituent units. Further, cellulose resins such as nitrocellulose and cellulose acetate, polyurethane resins, phenol resins, epoxy resins, phenoxy resins, urea resins, melamine resins, alkyd resins, polyester resins, polyamide resins, silicone resins and the like can be mentioned.

The amount of these binders is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, based on 1 part by weight of the ligand. The thickness of the layer is 50 in dry thickness.
μm or less, more preferably 30 μm or less.

[0134]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described, but it goes without saying that the present invention is not limited to these embodiments.

Examination of Magnetic Recording Medium First, in Experiments 1 to 6, the effect of holding a polyacid compound (ligand) on a magnetic recording medium was examined.

<Experiment 1> Here, a so-called coating type magnetic layer was made to hold an anti-seizure agent containing a polyacid compound (ligand) to prepare a magnetic tape, and recording was performed using this magnetic tape. Played.

Specifically, first, the following composition was prepared, and 100 parts by weight of acicular metallic iron magnetic particles (specific surface area: 53.9 cm ² / g, coercive force: 1580 Oe, saturation magnetization: 120 emu / g) thermoplastic polyurethane Resin (average molecular weight 20,000) 10 parts by weight Vinyl chloride-vinyl acetate copolymer 10 parts by weight Carbon (average particle diameter 150 nm) 5 parts by weight α-alumina (average particle diameter 200 nm) 5 parts by weight Olive oil 3 parts by weight Mixed solvent (methyl ethyl ketone) / Methyl isobutyl ketone / toluene = 2: 1: 1) 220 parts by weight This composition was mixed in a ball mill for 48 hours, and then 3.5 parts by weight of a curing agent composed of polyisocyanate was added, followed by further mixing for 30 minutes. did.

The magnetic paint thus obtained was applied on a 7 μm-thick polyethylene terephthalate film so that the thickness after drying was 2 μm. afterwards,
Drying and calendering were performed, and the magnetic layer was formed by leaving in an oven at 60 ° C. for 20 hours to promote curing.

Further, this was cut into a width of 8 mm, and an anti-seizure agent described later was applied to the surface of the magnetic layer by a dipping method to complete a magnetic tape.

The anti-seizure agent used here is obtained by dissolving a ligand (polyacid compound) having the general formula shown in the following Chemical Formulas 40 and 41 in toluene.

[0141]

Embedded image

[0142]

Embedded image

In addition, when the substituents X ^{1 to} X ⁴ in Chemical Formula ⁴⁰ are COOH or COOM,
Compounds represented by (Formula (A)) to Formula 47 (Formula (F)) may be mentioned, but here, Formula 42 (Formula (A))
The substituents R ^{15 to} R ¹⁸ , Y ^{1 to} Y
⁴ uses the compound A-1 as shown in Table 1, and
(Formula (B)) includes substituents R ^{19 to} R ^19
23, Y ^{5 ~Y 8} compounds as shown in Table 2 B-. 1 to
B-7 was used. The compound represented by Chemical Formula 44 (Formula (C)) is referred to as Compound C-1, and the compound represented by Chemical Formula 45 (Formula (D)) is represented by Compound D-1 and Chemical Formula 46 (Formula (E)). Are represented by compound E-1 and those represented by formula (F) are represented by compound F-1.

[0144]

Embedded image

[0145]

Embedded image

[0146]

Embedded image

[0147]

Embedded image

[0148]

Embedded image

[0149]

Embedded image

[0150]

[Table 1]

[0151]

[Table 2]

In the case where the substituents X ^{1 to} X ⁴ in Chemical Formula ⁴⁰ are PO ₃ H ₂ or PO ₃ HM,
Compound represented by (Formula (G)), Chemical formula 49 (Formula (H))
Embedded image wherein, in this case,
(Formula (H)) includes substituents R ^{28 to} R ^{28.
32, z 5 ~z 8, z} 5 '~z 8' is with a compound H-1 to H-6 as shown in Table 3.

[0153]

Embedded image

[0154]

Embedded image

[0155]

[Table 3]

Further, the substituents X ^{1 to} X ⁴ in Chemical formula 40
Is CH ₂ COOH, for example, a compound represented by the formula (I), wherein the substituents R ^{51 to} R ⁵⁵ are compounds I-1 to R ⁵⁵ as shown in Table 4.
I-3 was used.

[0157]

Embedded image

[0158]

[Table 4]

On the other hand, as the substituents X ⁵ and X ⁶ in Chemical Formula 41 which are COOH or COOM, those represented by Chemical Formula 51 (formula (J)) or Chemical Formula 52 (formula (K)) can be mentioned. However, here, as a compound represented by Formula 51 (Formula (J)), a compound J-1 in which substituents R ^{33 to} R ³⁶ , Y ¹⁷ , and Y ¹⁸ are shown in Table 5 is used. (Equation (K))
The substituents R ^{37 to} R ⁴¹ , Y ¹⁹ and Y
²⁰ using the compound K-1 to K-7, as shown in Table 6.

[0160]

Embedded image

[0161]

Embedded image

[0162]

[Table 5]

[0163]

[Table 6]

In the case where the substituents X ⁵ and X ⁶ in Chemical Formula 41 are PO ₃ H ₂ or PO ₃ HM,
(Formula (L)) and those represented by Chemical Formula 54 (Formula (M)) are exemplified. In this case, the substituents R ^{46 to} R ⁵⁰ are represented by Chemical Formula 54 (Formula (M)). , Z ¹¹ , z ¹¹ ′, z
¹² and z ¹² ′ are compounds M-1 to M- as shown in Table 7.
6 was used.

[0165]

Embedded image

[0166]

Embedded image

[0167]

[Table 7]

Further, the substituents X ⁵ and X ⁶ in Chemical formula 41
Is CH ₂ COOH, for example, those represented by Formula 55 (Formula (N)), wherein the substituents R ^{56 to} R ⁶⁰ are compounds N-1 to R60 shown in Table 8. N
-3 was used.

[0169]

Embedded image

[0170]

[Table 8]

Then, each of the magnetic tapes coated with the ligands described above is incorporated into a cassette shell, respectively.
After making the cartridge, the evaluation was performed as follows. For the purpose of comparison, the same evaluation was performed on a magnetic tape to which the above-mentioned anti-seizure agent was not applied.

Specifically, first, the sliding surface with the magnetic tape has a magnetic head as shown in FIG. 1, ie, the pair of magnetic core halves 1 and 2 are made of a ferromagnetic oxide such as single crystal ferrite. A ferromagnetic metal thin film 3 having a high saturation magnetic flux density Bs, such as an FeAlSi alloy (Sendust), is formed on the magnetic core halves 1 and 2 as if the joining surfaces of the magnetic core halves 1 and 2 are notched obliquely. A VCR equipped with a magnetic head having a magnetic gap at the contact surface 3 was prepared.

Then, using such a video deck,
First, recording is performed on each magnetic tape for one minute, and its reproduction output is measured. After that, record for 20 minutes,
After the reproduction operation was repeated 10 times, the reproduction output was measured again, and the output reduction (level reduction) based on the initial reproduction output was obtained.

After performing such recording / reproducing operation, the sliding surface of the magnetic tape of the magnetic head mounted on the video deck was observed with a microscope. In addition, as a result of observation,
On the sliding surface of the magnetic tape in the magnetic head, a case where burn-in was generated on the ferromagnetic metal thin film 3 was evaluated as x, and a case where burn-in was not recognized was evaluated as ○.

Table 9 and Table 1 show the results of the level-down and microscopic observation in correspondence with the ligand contained in the anti-seizure agent.
0 is shown. Table 10 also shows the results of the magnetic tape to which the anti-seizure agent was not applied.

[0176]

[Table 9]

[0177]

[Table 10]

As shown in Tables 9 and 10, in the case of a magnetic tape in which the anti-seizure agent was not applied to the surface of the magnetic layer, the level was greatly reduced, and a seizure was generated on the surface of the magnetic head. On the other hand, in each of the magnetic tapes coated with the above-described ligand-containing anti-seizure agent, the level reduction was suppressed, and no seizure was observed on the surface of the magnetic head.

FIG. 2 shows a magnetic head after recording and reproduction on a magnetic tape coated with a ligand-containing anti-seizure agent, based on a micrograph. FIG. 3 shows a drawing of a magnetic head based on a photomicrograph of a magnetic head after recording / reproducing on a magnetic tape on which the anti-seizure agent is not applied to the surface of the magnetic layer. In FIG. 3, the ferromagnetic metal thin film 3
In contrast to FIG. 2, since the burn-in product 4 has been generated, the burn-in product 4 is not generated at all in FIG.

From the above results, it is understood that the use of a magnetic tape coated with a ligand, ie, a seizure preventive agent containing a polyacid compound, can prevent the generation of seizure on the magnetic head. Was.

<Experiment 2> In this experiment, a so-called coating type magnetic layer was internally added with a carboxylic acid together with the ligand described above.
A magnetic tape was produced.

Specifically, first, the same composition as prepared in Experiment 1 described above was further added with 6 parts by weight of carboxylic acid (oleic acid or myristic acid) and 5 parts by weight of ligand. On the other hand, in the same manner as in Experiment 1, mixing, addition of a curing agent, and mixing were performed.

Then, in the same manner as in Experiment 1, the magnetic paint thus obtained was applied on a polyethylene terephthalate film, dried, calendered, and subjected to a heat treatment for accelerating curing to form a magnetic layer. After the formation, it was cut to complete the magnetic tape. Here, since the anti-seizure agent was internally added to the magnetic layer, the anti-seizure agent was not applied to the surface of the magnetic layer.

The ligand internally added to the magnetic layer is represented by
2 (Formula (A)) in which the substituents in compounds A-1 and A-2 as shown in Table 11 and Chemical Formula 43 (Formula (B)) in which the substituents as shown in Table 12 1,3,3
5, in addition to B-8 to B-12, and also chemical formula 44 (formula (C))
Compounds C-1 and D- represented by Formula 47 (Formula (F))
1, E-1, and F-1 were used. In addition, compounds G-1 and G-2 in which the substituents in Chemical Formula 48 (Formula (G)) are as shown in Table 13, and the substituents in Chemical Formula 49 (Formula (H)) are as shown in Table 14. Compound H-1,3,5, H
-7 to H-11 were also used. Further, Formula 51 (Formula (J))
Is a compound J- as shown in Table 15
1, J-2, and compounds K-1, 3, 5, and K-8 to which the substituents in Chemical Formula 52 (Formula (K)) are shown in Table 16.
In addition to K-12, compounds L-1 and L-2 in which the substituents in Chemical formula 53 (Formula (L)) are as shown in Table 17,
Compounds M-1, 3, 5, and M-7 to M-11 having substituents in (Formula (M)) shown in Table 18 were also used. In addition, these ligands include the same compounds as those used in Experiment 1, and these compounds are denoted by the same reference numerals as in Experiment 1.

[0185]

[Table 11]

[0186]

[Table 12]

[0187]

[Table 13]

[0188]

[Table 14]

[0189]

[Table 15]

[0190]

[Table 16]

[0191]

[Table 17]

[0192]

[Table 18]

Then, a magnetic tape in which each of the above-described ligands and oleic acid are combined and internally added to the magnetic layer, and a combination of each of the above-described ligands and myristic acid are internally added to the magnetic layer. Each of the magnetic tapes was assembled into a cassette shell to form a cartridge, and the cartridge was evaluated as follows. For comparison, a magnetic tape containing only oleic acid and a magnetic tape containing only myristic acid were similarly evaluated.

The evaluation method is the same as that shown in Experiment 1. The evaluation results are shown in Tables 19 to 22, together with the combination of the ligand and the carboxylic acid internally added to the magnetic layer. Table 23 also shows the evaluation results of the magnetic tape containing only the ligand, the magnetic tape containing only oleic acid, and the magnetic tape containing only myristic acid.

[0195]

[Table 19]

[0196]

[Table 20]

[0197]

[Table 21]

[0198]

[Table 22]

[0199]

[Table 23]

As shown in Tables 19 to 23, in the magnetic tape in which only the carboxylic acid was internally added to the magnetic layer,
A significant level drop occurred, causing burn-in on the surface of the magnetic head.On the other hand, a magnetic tape in which the ligand and carboxylic acid were combined and added to the magnetic layer suppressed the level drop. No burn-in to the surface of the magnetic head was observed.

When a ligand is added without using a carboxylic acid, the generation of seizures is suppressed as compared with the case where no ligand is added, but some seizures are observed. In this case, the level is reduced by about -4 dB. From this, it was found that when the ligand is used in combination with the carboxylic acid, the effect of preventing the sticking of seizures by the ligand is more remarkably exhibited. It is considered that this is because the carboxylic acid is adsorbed on the magnetic powder and prevents the ligand from adsorbing on the magnetic powder.

A magnetic head after recording / reproducing on a magnetic tape in which a ligand and a carboxylic acid are combined and internally added to a magnetic layer is illustrated on the basis of a micrograph, as shown in FIG. FIG. 3 shows a drawing of a magnetic head after recording and reproduction on a magnetic tape containing only carboxylic acid, based on a micrograph.

From the above results, when a magnetic tape in which a ligand, that is, a polyacid compound and a carboxylic acid are combined and internally added to a magnetic layer, is used, it is possible to further prevent generation of a seizure on a magnetic head. It turned out to be.

An experiment was also conducted in the case where carboxylic acid was applied to the surface of the magnetic layer. However, in this case, the effect of reducing the level was not so much improved. Therefore, the carboxylic acid is desirably used by being internally added to the magnetic layer, rather than being applied to the surface of the magnetic layer.

<Experiment 3> Here, a magnetic tape was prepared by applying the above-mentioned anti-seizure agent containing a ligand to the surface of a carbon film on a so-called evaporation type magnetic layer.

Specifically, first, a 10 μm-thick polyethylene terephthalate film was coated with Co by oblique deposition.
And a 100 nm thick ferromagnetic metal thin film was formed, and then a 10 nm thick carbon film was formed on the surface of the ferromagnetic metal thin film by a sputtering method.

Further, this was cut into an 8 mm width, and an anti-seizure agent was applied to the surface of the carbon film by dipping to complete a magnetic tape.

The anti-seizure agent used here was obtained by dissolving the same ligand as used in Experiment 2 in toluene.

Then, the magnetic tape coated with each of the above ligands is incorporated into a cassette shell, respectively.
After making the cartridge, the same evaluation as in Experiment 1 was performed.
For the purpose of comparison, the same evaluation was performed on a magnetic tape to which no ligand was applied. Tables 24 and 25 show the evaluation results.

[0210]

[Table 24]

[0211]

[Table 25]

As shown in Tables 24 and 25, in the case of a magnetic tape in which the anti-seizure agent was not applied to the surface of the carbon film, the level was greatly reduced, and a seizure was generated on the surface of the magnetic head. On the other hand, in each of the magnetic tapes to which the anti-seizure agent containing the ligand was applied, the level reduction was suppressed, and no seizure on the surface of the magnetic head was observed.

The drawing of the magnetic head after recording / reproducing on the magnetic tape coated with the ligand, based on the micrograph, is the same as FIG. 2, and the ligand is not coated. Drawing the magnetic head after performing recording and reproduction on the magnetic tape based on a micrograph,
It became the same as FIG.

From the above results, the use of a magnetic tape coated with a ligand, that is, an anti-seizure agent containing a polyacid compound on the surface of a carbon film can prevent generation of a seizure on a magnetic head. It turned out to be.

<Experiment 4> Here, an anti-seizure agent containing a compound containing phosphorus together with a ligand was applied to the surface of a carbon film on a so-called evaporation type magnetic layer to produce a magnetic tape.

Specifically, first, a ferromagnetic metal thin film and a carbon film were formed in the same manner as in Experiment 3 described above, and then cut to complete a magnetic tape. Then, an anti-seizure agent formed by dissolving a compound containing phosphorus together with a ligand in toluene was applied to complete a magnetic tape.

As the ligand contained in the anti-seizure agent, the same compounds as those used in Experiment 3 were used.

The compound containing phosphorus contained in the anti-seizure agent together with this ligand is represented by the following formula (O).
Which is represented by a general formula:
Specifically, as the compound containing phosphorus, the substituent R ³
O-1, O-2, P-1 to to R ¹⁴ are shown in Table 26,
P-2, Q-1, Q-2, R-1, and R-2 were used.

[0219]

Embedded image

[0220]

Embedded image

[0221]

Embedded image

[0222]

Embedded image

[0223]

[Table 26]

Then, a magnetic tape coated with an anti-seizure agent containing each of the ligands and the compound containing phosphorus as described above was incorporated into a cassette shell to form a cartridge. An evaluation was performed. For the purpose of comparison, the same evaluation was performed on a magnetic tape to which a seizure preventing agent containing no ligand was applied. Tables 27 to 29 show these evaluation results.

[0225]

[Table 27]

[0226]

[Table 28]

[0227]

[Table 29]

As shown in Tables 27 to 29, in the case of a magnetic tape in which only the compound containing phosphorus was applied to the magnetic layer, the level was greatly reduced, and burn-in was generated on the surface of the magnetic head. On the other hand, in a magnetic tape coated with an anti-seizure agent combining a ligand and a compound containing phosphorus, the level reduction is suppressed,
No seizure on the surface of the magnetic head was observed.

In Experiment 3, a magnetic tape in which only a ligand was coated on a magnetic layer without using a phosphorus-containing compound was evaluated, but a common ligand was used in Experiment 3. It can also be seen that when used, better results are obtained when used in combination with a compound containing phosphorus.

A magnetic head after recording / reproducing on a magnetic tape in which a ligand and a compound containing phosphorus are combined and internally added to a magnetic layer is shown in FIG. FIG. 3 is a drawing of a magnetic head after recording and reproduction on a magnetic tape containing only a phosphorus-containing compound, based on a micrograph.

From the above results, the use of a magnetic tape in which a ligand, ie, a polyacid compound and a compound containing phosphorus are combined and internally added to a magnetic layer, further prevents the generation of seizure on a magnetic head. I knew I could do it.

<Experiment 5> Here, a magnetic tape was manufactured by internally adding the above-described anti-seizure agent containing a ligand to the back coat layer formed on the side opposite to the magnetic layer.

Specifically, first, a so-called coating type magnetic layer was formed on a 7 μm-thick polyethylene terephthalate film in the same manner as in Experiment 1. And
The following composition is prepared: carbon black (average primary particle size 50 nm) 100 parts by weight Thermoplastic polyurethane resin (average molecular weight 20,000) 60 parts by weight Vinyl chloride-vinyl acetate copolymer 60 parts by weight Olive oil 5 parts by weight Mixed solvent ( Methyl ethyl ketone / methyl isobutyl ketone / toluene = 2: 1: 1) 1150 parts by weight This composition was mixed in a ball mill for 10 hours, and then a curing agent composed of polyisocyanate 3.5 parts by weight Ligand 25 parts by weight was added. Then, the mixture was further mixed for 30 minutes, and the thus-obtained back coat layer coating material was applied to the surface of the polyethylene terephthalate film opposite to the magnetic layer forming surface so that the thickness after drying was 0.8 μm. .

Thereafter, the magnetic tape was dried and calendered, and a magnetic tape was completed in the same manner as in Experiment 1 in which heat treatment and cutting for accelerating curing were performed.

The ligand used here is the same as that used in Experiment 4.

Then, after each of the above-described ligands and the magnetic tape in which the back coat layer was internally added was incorporated into a cassette shell to form a cartridge, the same evaluation as in Experiment 1 was performed. For the purpose of comparison, the same evaluation was performed on a magnetic tape to which no ligand was added. Tables 30 and 31 show the evaluation results.

[0237]

[Table 30]

[0238]

[Table 31]

As shown in Tables 30 and 31, in the magnetic tape in which the ligand was not internally added to the back coat layer, the level was greatly reduced, and burn-in was generated on the surface of the magnetic head. On the other hand, in each of the magnetic tapes in which the ligand was internally added to the back coat layer, the level reduction was suppressed, and burn-in on the surface of the magnetic head was not observed.

The drawing of the magnetic head after recording / reproducing on the magnetic tape with the ligand added thereto is based on a micrograph, and the drawing is the same as FIG. 2, and the ligand is added internally. Drawing the magnetic head after performing recording and reproduction on a magnetic tape that is not based on a micrograph,
It became the same as FIG.

From the above results, it was found that the use of a magnetic tape in which a ligand, that is, a polyacid compound was internally added to a back coat layer, could prevent generation of seizure on a magnetic head. .

<Experiment 6> Here, a titanate-based coupling agent was added to the so-called coating type magnetic layer together with the above-mentioned ligand to prepare a magnetic tape.

Specifically, first, the following composition was prepared, and 100 parts by weight of an Fe-based metal ferromagnetic powder (coercive force: 160 kA / m, saturation magnetization: 145 Am ² / kg, specific surface area: 51 m ² / g, length: Shaft length 0.08 μm, needle ratio 3) Polyvinyl chloride resin (trade name MR110, manufactured by Zeon Corporation) 14 parts by weight Polyester polyurethane resin (manufactured by Toyobo) 3 parts by weight Al ₂ O ₃ 5 parts by weight Titanate coupling agent 3 parts by weight Stearic acid 1 part by weight Heptyl stearate 1 part by weight Methyl ethyl ketone 150 parts by weight Cyclohexanone 150 parts by weight After kneading the composition into an extruder,
The mixture was dispersed in a sand mill for 6 hours. Then, a magnetic coating material was prepared by adding 3 parts by weight of polyisocyanate and a ligand in the amounts shown in Table 19 to the obtained coating material.

The magnetic paint thus obtained was applied on a 7 μm thick polyethylene terephthalate film so that the thickness became 6.5 μm. Subsequently, the formed magnetic coating film was subjected to an orientation treatment using a solenoid coil, and then dried, calendered, and cured to form a magnetic layer.

Next, the following composition was prepared: 100 parts by weight of carbon black (Asahi # 50) 100 parts by weight of a polyester polyurethane resin (Nipporan N-2304) 500 parts by weight of methyl ethyl ketone 500 parts by weight of toluene A back coating was prepared by kneading and dispersing, and the back coating was applied to the surface of the nonmagnetic support opposite to the side on which the magnetic layer was formed, and dried to form a backcoat layer.

The original tape on which the magnetic layer and the back coat layer were formed was cut into a width of 8 mm to complete a magnetic tape.

The ligand to be internally added to the magnetic layer is the compound B represented by the above formula (B).
-8, B-12, compounds H-7 and H-11 represented by Formula 49 (formula (H)), and compounds K-8 and K-12 represented by Formula 52 (formula (K)). A compound M-7 represented by 54,
In addition to using M-11, Compound B-13 represented by Formula 43 and having the following substituents was used.

B-13: R ¹⁹ , R ²¹ , R ²³ = C
H ₃ , R ²⁰ , R ²² , Y ^{5 to} Y ⁸ ＨH The titanate-based coupling agent used was a compound represented by Chemical Formulas 60 to 64.

[0249]

Embedded image

[0250]

Embedded image

[0251]

Embedded image

[0252]

Embedded image

[0253]

Embedded image

Then, the above-mentioned ligands and titanate-based coupling agents were combined and magnetic tapes internally added to the magnetic layer were respectively incorporated into cassette shells to form cartridges. The results are shown in Experiment 1. The evaluation of the level down was performed in the same manner as the above. Table 32 shows the results. Table 32 also shows the evaluation results of a magnetic tape containing only a titanate-based coupling agent and a magnetic tape containing only a ligand.

[0255]

[Table 32]

As a result of the evaluation, in the case of a magnetic tape in which a ligand and a titanate-based coupling agent were combined and internally added to a magnetic layer, a magnetic tape in which only a ligand was internally added to a magnetic layer, a titanate-based cup As compared with a magnetic tape in which only a ring agent is internally added to a magnetic layer, sticking of a seizure to the surface of a magnetic head is prevented, and a level reduction is suppressed as shown in Table 32.

From this, it was found that when the ligand was used in combination with a titanate coupling agent, the effect of preventing the sticking of seizures by the ligand was more remarkably exhibited.

Here, the internal addition amount of the ligand was varied in various ways. As shown in Table 32, when the internal addition amount of the ligand was as small as 0.05 part by weight, the ligand was added. Is not much different from the result without the internal addition.

Further, the leveling down is suppressed as the amount of the ligand added is increased. However, when the ligand is added in an amount exceeding 10 parts by weight, the dispersibility of the magnetic powder is reduced. Therefore, the internal addition amount of the ligand is 0.3 to 100 parts by weight of the magnetic powder.
20 parts by weight, more preferably 0.3 to 10 parts by weight.

In this case, the type of the titanate-based coupling agent was also changed, and although a sufficient effect was obtained in each case, a slight difference was observed in the degree of the effect. This difference is considered to be due to the difference in the adsorptivity of the titanate-based coupling agent to the magnetic powder.

An experiment was conducted also in the case where a titanate-based coupling agent was applied to the surface of the magnetic layer. However, in this case, the effect of reducing the level was not so much improved. Therefore, it is preferable that the titanate-based coupling agent be used by being internally added to the magnetic layer, rather than being applied to the surface of the magnetic layer.

Examination of Cleaning Tape Next, in Experiments 7 to 9, the effect of retaining the polyacid compound on the cleaning tape was examined.

<Experiment 7> First, a cleaning tape was manufactured as follows.

Specifically, first, the following composition was prepared, and 10 parts by weight of a thermoplastic polyurethane resin (average molecular weight: 20,000) 10 parts by weight of a vinyl chloride-vinyl acetate copolymer 10 parts by weight of carbon (average particle size of 150 nm) 5 parts by weight 5 parts by weight of ligand 5 parts by weight of mixed solvent 220 parts by weight of mixed solvent (methyl ethyl ketone / methyl isobutyl ketone / toluene = 2: 1: 1) The composition was mixed for 48 hours by a ball mill, and then a curing agent composed of polyisocyanate was added. 5 parts by weight were added and mixed for another 30 minutes.

The thus-obtained cleaning paint was applied on a 7 μm-thick polyethylene terephthalate film so that the thickness after drying was 2 μm.
Thereafter, the cleaning layer was cured by leaving it in an oven at 60 ° C. for 20 hours to promote curing, and was cut into 8 mm width to prepare a cleaning tape.

Here, as the ligand, compounds A-1, A-2, and 43 (formula (B)) represented by formula (A) shown in the study of the magnetic recording medium described above are used. Compounds B-1, B-3, B-5, B-8 to B-12 represented by
Compound C-1 represented by Formula 4 (Formula (C)), Compound D-1 represented by Formula 45 (Formula (D)), Formula 46 (Formula (E))
A compound E-1, a compound F-1 represented by the formula (F), a compound G-1, G-2 represented by the formula (G): Compound H represented by formula (H)
-1, H-3, H-5, H-7, H-8 to H-11, compounds J-1 and J-2 represented by the formula (J), and formula 52 (the formula (K )) Compounds K-1, K-3, K
-5, K-8 to K-12, Compounds L-1, L-2 represented by Formula 53 (Formula (L)), Compounds M-1, M represented by Formula 54 (Formula (M)) -3, M-5, M-7 to M-11 were used.

Then, each of the cleaning tapes described above was incorporated into a cassette shell to form a cartridge, and the cartridge was evaluated as follows.

For the purpose of comparison, the same evaluation was carried out for a cleaning tape having no ligand added to the cleaning layer.

[0269] Specifically, first, recording is performed on a magnetic tape for 20 minutes using the same video deck as that used in Experiment 1, and then the reproduction operation is repeated until the level is reduced by 5 dB. The cleaning tape was run for one minute on the VCR in which the level was reduced as described above. Thereafter, the reproduction output was measured again to evaluate the recovery from the level reduction. The reproduction output was indicated by a value where the initial reproduction output was 0 dB. The recovered output is shown in Tables 33 to 36 together with the type of ligand used.

[0270]

[Table 33]

[0271]

[Table 34]

[0272]

[Table 35]

[0273]

[Table 36]

As shown in Tables 33 to 36, when the cleaning tape in which the ligand was internally added to the cleaning layer was run on the VCR, the ligand was applied to the cleaning layer and the cleaning layer was internally added. The level reduction was greatly improved compared to running a cleaning tape on a VCR without cleaning.

<Experiment 8> A cleaning tape was prepared in the same manner as in Experiment 6, except that a ligand was not added to the cleaning layer, and after the cutting, a solution in which the ligand was dissolved was dip-coated on the surface of the cleaning layer. Produced. The ligand dissolved in the solution was the same as that used in Experiment 6, and the concentration of the solution was 10 mM. The solvent is a mixed solvent of toluene and alcohol.

After the cleaning tape prepared as described above was assembled into a cassette shell to form a cartridge, the cartridge was run on a video deck whose level had been reduced in the same manner as in Experiment 6, and the output recovery was measured. . In addition, for the purpose of comparison, the same evaluation was performed on a cleaning tape to which neither a ligand was applied nor internally added. The results are shown in Tables 37-37 together with the type of ligand used.
It is shown in Table 40.

[0277]

[Table 37]

[0278]

[Table 38]

[0279]

[Table 39]

[0280]

[Table 40]

As shown in Tables 37 to 40, when a cleaning tape having a ligand applied to the surface of the cleaning layer was used, a cleaning tape having neither the ligand applied to the cleaning layer nor internally added thereto was used. Compared to running on a VCR, the level down has recovered significantly.

<Experiment 9> A solution in which a ligand was dissolved at a concentration of 10 mM in a mixed solvent of toluene and alcohol was prepared. On the other hand, a nonwoven fabric (grade 193, manufactured by Dexter) made of polypropylene was cut into a width of 8 mm, and a solution in which the ligand was dissolved was dip-coated to prepare a cleaning tape.

After the cleaning tape prepared as described above was incorporated into a cassette shell to form a cartridge, the cartridge was run on a video deck whose level had been reduced in the same manner as in Experiment 6, and the output recovery was measured. . The results are shown in Tables 41 to 44 together with the types of ligands used.

[0284]

[Table 41]

[0285]

[Table 42]

[0286]

[Table 43]

[0287]

[Table 44]

As shown in Tables 41 to 44, when the cleaning tape in which the nonwoven fabric was impregnated with the ligand was run on a VCR, the level reduction was greatly recovered.

From the results of Experiments 7 to 9, it was found that the polyacid compound was suitable as a cleaning tape cleaning agent. It was also found that this ligand exerts a good cleaning effect when it is applied to the surface of the support or the surface of the cleaning layer, and when it is internally added to the cleaning layer.

[0290]

As is clear from the above description, when a ligand capable of forming a complex with a metal, that is, a polyacid compound is held on a magnetic recording medium, generation of burn-in on a magnetic head is prevented. become able to.

For this reason, when the magnetic recording medium according to the present invention is used, even if the sliding time is increased or the scanning speed is increased to achieve long-term recording, the spacing loss can be suppressed, and the error can be reduced. The rate is prevented from rising.

When the polyacid compound is used as a cleaning agent for a cleaning tape, seizures adhered to the magnetic head can be removed without causing wear and damage to the magnetic head.

Therefore, this cleaning tape is
It is suitable as a cleaning tape for a recording / reproducing system in which the head gap is as small as 0.3 μm or less and the magnetic head slides at high speed with respect to the tape.

[Brief description of the drawings]

FIG. 1 is a plan view showing a sliding surface of a magnetic head used for recording and reproduction on a magnetic tape with the magnetic tape.

FIG. 2 is a plan view illustrating a magnetic head after performing recording and reproduction on a magnetic tape to which the present invention is applied, based on a micrograph.

FIG. 3 is a plan view illustrating a magnetic head after performing recording and reproduction on a conventional magnetic tape based on a micrograph.

[Explanation of symbols]

1, half magnetic core, 3 ferromagnetic metal thin film, 4
Burn-in

Continued on the front page (72) Inventor Haruo Watanabe 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Ken Takeshi 6-35-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sonny shares Inside the company (72) Inventor Kenichi Kurihara 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation

Claims (11)

[Claims] 1. A magnetic recording medium comprising a non-magnetic support and at least a magnetic layer formed thereon, wherein the anti-seizing agent containing a polyacid compound is retained. 2. The polyacid compound according to claim 1, wherein
2. The magnetic recording medium according to claim 1, wherein the magnetic recording medium is at least one selected from the group consisting of: Embedded image Embedded image 3. The magnetic layer is formed by applying a magnetic paint mainly composed of a magnetic powder and a binder, and the anti-seizure agent is applied to the surface of the magnetic layer. 3. The magnetic recording medium according to claim 2, wherein the magnetic recording medium is internally added in the layer. 4. The magnetic recording medium according to claim 3, wherein a titanate-based coupling agent is applied to the surface of the magnetic layer or is internally added to the magnetic layer. 5. The magnetic material according to claim 4, wherein the titanate-based coupling agent has introduced at least one of an amino group, a phosphate group, an acyl group, a hydroxyl group, a carbonyl group, and an alkyl group. recoding media. 6. The magnetic recording medium according to claim 3, wherein a carboxylic acid is applied to the surface of the magnetic layer, or is internally added to the magnetic layer. 7. The magnetic layer according to claim 2, wherein the magnetic layer is a metal magnetic thin film, a carbon film is formed on the metal magnetic thin film, and the anti-seizing agent is applied to the surface of the carbon film. Magnetic recording medium. 8. The magnetic recording medium according to claim 7, wherein the anti-seizure agent further contains a compound containing phosphorus represented by at least one selected from the following chemical formulas (3) to (6). Embedded image Embedded image Embedded image Embedded image 9. A backcoat layer is formed on the surface of the nonmagnetic support opposite to the surface on which the magnetic layer is formed, and the anti-seizure agent is applied to the surface of the backcoat layer, or 3. The magnetic recording medium according to claim 2, wherein the magnetic recording medium is internally added to the back coat layer. 10. A cleaning tape comprising a support and an anti-seizure agent containing a polyacid compound held thereon. 11. The cleaning tape according to claim 10, wherein the compound is at least one selected from the following chemical formulas (7) and (8). Embedded image Embedded image