JPH1017584A - Lubricant substance and magnetic recording medium using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lubricant substance which comprises a specific cyclic phosphoric ester derivative, can allow two bodies contacting with each other to slide between them with low friction and low abrasion regardless of high speed, low speed, high loading and low loading, and is useful in production of a magnetic recording medium of excellent durability. SOLUTION: A cyclic phosphoric ester derivative of formula I [R is a hydrocarbon group, a fluorinated carbon group; X is O, NR1 (R1 is H, a hydrocarbon group)], formula H, formula III, formula IV and the like is used to prepare a lubricant substance which can slide between two solid substances contacting with each other regardless of high speed, low speed, high loading or low loading with low friction and low abrasion. Any one of these phosphoric ester derivatives is used as a lubricant to form a lubricant later of 0.5-20mg/m<2> on a magnetic thin layer of a magnetic powder containing ferromagnetic metal whereby the objective magnetic recording medium excellent in durability is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating substance and a magnetic recording medium using the lubricating substance, and more particularly, to a low friction between two solids contacting at high speed, low speed, high load and low load. A lubricating substance that slides with low wear,
The present invention relates to a magnetic recording medium using the lubricating substance and having excellent durability.

[0002]

2. Description of the Related Art For the purpose of extending the service life of equipment and devices by sliding between two solids in contact with low friction and low abrasion, hardening of solid surfaces and development of lubricating substances have been carried out. In the field of OA equipment in particular, there is a strong demand for size reduction, and precision mechanisms have been adopted for sliding parts year by year. For future equipment in which precision parts slide continuously or intermittently in a wide range of environments, the As described above, it is necessary to reduce the friction and abrasion at the start, at the end, and at the time of sliding, and to reduce the load on the motor and the like. Therefore, in the protective lubrication system, a hard and hard to wear surface layer is provided at a sliding portion, and a grease or oil-like semi-solid or liquid lubricating substance is used as a lubricating substance.

[0003] A magnetic recording medium formed by applying a magnetic paint comprising a magnetic powder, a binder resin, an organic solvent and other necessary components on a non-magnetic support and drying the same is run while contacting a magnetic head or the like. Therefore, it is required that the magnetic layer is easily worn, the coefficient of friction of the magnetic layer is small and the durability is excellent, and a ferromagnetic metal or an alloy thereof is coated on a non-magnetic support by vacuum deposition or the like. The ferromagnetic metal thin-film type magnetic recording medium that is formed by coating is easier to achieve a higher coercive force and a thinner magnetic layer than the coating type magnetic recording medium, and has excellent high-density recording characteristics, Since a certain binder resin is not used, and the surface smoothness of the ferromagnetic metal thin film layer and the protective film is good, the coefficient of friction with the magnetic head becomes large, so that the magnetic head is susceptible to wear and damage, and durability and running properties are poor.

Thus, for example, in the case of a magnetic recording medium,
Various lubricating substances such as a perfluoropolyether lubricating substance, a carboxylic acid lubricating substance, and a partially fluorinated carboxylic acid lubricating substance may be present on a ferromagnetic metal thin film layer (Japanese Patent Laid-Open No. No. 85427, JP-A-62-23611
No. 8, JP-A-2-210615), and durability and running properties are improved by including these fluorine-based lubricating substances in a magnetic layer.

[0005]

However, in precision instruments in which contact portions have been smoothed, high-speed, low-speed,
Low friction between two solids contacting regardless of high load and low load,
A lubricating substance that can be slid with low wear has not been obtained, and the problem of poor starting or accidental sudden increase in frictional force during sliding cannot be avoided. Further, in a magnetic recording medium, when a fluorine-based lubricating substance is present on a ferromagnetic metal thin film layer or when a fluorine-based lubricating substance is contained in a magnetic layer, durability and running properties are improved, Not enough yet.

The present invention has been made in view of such a situation, and even in future precision equipment in which the contact portion is being smoothed, the contact is made irrespective of high speed, low speed, high load, and low load.
Obtain a lubricating substance that can slide between solids with low friction and low abrasion. Also, by using this lubricating substance for a magnetic recording medium, we aim to obtain a magnetic recording medium with excellent durability. Things.

[0007]

The lubricating substance of the present invention has the following general formulas (1) to (8):

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Wherein R is a hydrocarbon group or a fluorocarbon group, X is O or NR ₁ and R ₁ is hydrogen or a hydrocarbon group. Or any of the above phosphoric acid derivatives.

The magnetic recording medium of the present invention has the following general formulas (1) to (8):

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Wherein R is a hydrocarbon group or a fluorocarbon group, X is O or NR ₁ and R ₁ is hydrogen or a hydrocarbon group. Any of these phosphoric acid derivatives is used as a lubricating substance.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the following general formulas (1) to (8):

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Embedded image (where R is a hydrocarbon group or a fluorocarbon group, X is O or NR ₁ , and R ₁ is a hydrogen or hydrocarbon group). Due to its excellent lubricating function and a phosphoric acid group in the molecule, this type of phosphoric acid derivative is strongly adsorbed on the solid surface by the action of the phosphoric acid group in the molecule, resulting in dense lubrication. A coating can be formed to slide between two solids in contact with low friction and low wear.

When this kind of phosphoric acid derivative is used for a magnetic recording medium, it is strongly adsorbed on the surface of the magnetic layer or the surface of the protective film by the action of a phosphoric acid group in the molecule and stably exists. The magnetic recording medium can be stably contained therein, and the durability of the magnetic recording medium can be sufficiently improved.

Such a phosphoric acid derivative of the present invention may be synthesized by any method. For example, an aliphatic alcohol and a phosphorus oxychloride derivative may be synthesized in three different forms.
It can be synthesized by reacting in the presence of a secondary amine.

The phosphoric acid derivative synthesized in this manner is represented by the above-mentioned general formulas (1) to (8).
Is a hydrocarbon group or a fluorocarbon group. Examples of the hydrocarbon group include an alkyl chain, a polyether chain, a polyester chain, and a polycarbonate chain, which are saturated or unsaturated. Or may have a branch, and may be a cyclic one.

As the fluorocarbon group, a perfluoroalkyl chain and a perfluoropolyether chain may be mentioned as suitable ones, but only a part of the constituent carbon may be hydrogenated. It may be saturated, unsaturated, branched, or cyclic. In order to obtain the lubricity unique to fluorine,
It is desirable that the number of constituent fluorine-bonded carbon atoms be one or more, particularly four or more.

Further, X is O or NR ₁ and R ₁
Is hydrogen or a hydrocarbon group, and as the hydrocarbon group, alkyl chains, polyether chains, polyester chains, and polycarbonate chains are suitable as described above. They may be present or have a branch, and may be cyclic.

When such a phosphoric acid derivative is used as a lubricating substance, it may be used in combination with another lubricating substance, if necessary, such as a fatty acid or a metal salt thereof.
Commonly used are aliphatic esters, aliphatic amides, aliphatic alcohols, monosulfides, paraffins, silicone compounds, aliphatic and fluoride esters, perfluoropolyethers, polytetrafluoroethylene, and the like. Lubricating substances are preferably used in combination.

Further, phosphorus extreme pressure agents such as trioleyl phosphate, sulfur extreme pressure agents such as benzyl disulfide, halogen extreme pressure agents such as allyl bromide, and organometallic extreme pressure agents such as zinc diisobutyldithiophosphate. An extreme pressure agent or the like may be used in combination.

In order to use such a phosphoric acid derivative as a lubricating substance for a magnetic recording medium, the phosphoric acid derivative is converted into a general-purpose organic solvent such as alcohol, hydrocarbon, ketone, ether or the like. Dissolve in a fluorine-based solvent and apply or spray this solution on a magnetic layer or protective film previously formed on a non-magnetic support, or dry, or vice versa This is performed by a method such as dipping and drying the film.

In addition, this kind of phosphoric acid derivative is mixed and dispersed with a magnetic powder, a binder resin, an organic solvent and other additives to prepare a magnetic paint, and this magnetic paint is coated on a non-magnetic support such as a polyester film. It is also used by a method such as applying to the body by any means such as spraying or rolling and drying.

A solution in which this kind of phosphoric acid derivative is dissolved may be applied again to the magnetic layer thus formed by coating, spraying, dipping, etc. in the same manner as described above. Further, after the adhesion, excess lubricating substances and the like may be washed with a solvent. Alternatively, a lubricating substance may be contained on the opposite side of the magnetic layer, and the image may be transferred to the magnetic layer.

When the magnetic layer in which this type of phosphoric acid derivative is present is a ferromagnetic metal thin film layer, carbon (diamond or amorphous) is formed on the ferromagnetic metal thin film layer by vacuum deposition, sputtering, plasma, or the like. State),
A protective film made of silicon oxide, zirconium oxide, chromium oxide, an organic compound, or the like may be provided, or a protective film containing fluorine, silicon, or the like may be provided. Further, the ferromagnetic metal thin film layer may have a surface to which a slight amount of moisture has adhered, or may have a rust preventive such as a benzotriazole type applied thereto.

Further, the surface of the protective film or the like provided on the ferromagnetic metal thin film layer may be subjected to an oxygen and ammonia plasma treatment. Active species can be deposited, and the phosphoric acid derivative can be stably present without lowering the hardness of the protective film. Furthermore, the phosphoric acid derivative can be stably present by performing ultraviolet irradiation treatment, heat treatment, or the like. These treatments may be performed before the phosphoric acid derivative is adhered or after the phosphoric acid derivative is adhered, or may be performed after the phosphoric acid derivative is adhered and after the excess phosphoric acid derivative is washed.

The amount of this type of phosphoric acid derivative applied onto the ferromagnetic metal thin film layer is 0.5 to 2 times the surface of the ferromagnetic metal thin film layer.
The content is preferably in the range of 0 mg / m ^{2. If} the amount is less than 0 mg / m ² , it is difficult to uniformly attach a lubricating substance to the surface of the ferromagnetic metal thin film layer, and the still durability cannot be sufficiently improved. On the other hand, if the amount is too large, the magnetic head and the ferromagnetic metal thin film layer are undesirably stuck.

In the case where it is contained in the magnetic layer, 10
If the amount is less than mg / m ^{2, the} desired effect cannot be obtained.
If it is more than 0 mg / m ^2, it sticks to the magnetic head and it becomes impossible to run. Therefore, it is preferable that the amount is in the range of 10 to 100 mg / m ² .

The amount and content of the lubricating substance may be determined, for example, by immersing a magnetic tape coated with the lubricating substance in a solvent overnight, extracting the lubricating substance with a solvent, and then performing gas chromatography or liquid chromatography. It can be determined by chromatography or the like.

In the case of a ferromagnetic metal thin film layer, the magnetic layer is formed of Co, Ni, Fe, Co--Ni, Co--Cr, Co
-P, Co-Ni-P, Fe-Co-B, Fe-Co-
Ni, Co-Ni-Fe-B, Fe-Ni, Fe-C
o, Co-Pt, Co-Ni-Pt or various ferromagnetic materials such as those obtained by adding oxygen to these materials by vacuum deposition, ion plating, sputtering, plating, etc., using a non-magnetic material such as a polyester film. It is formed by a method such as attaching it to one or both surfaces of a support, and is usually formed to a thickness in the range of 0.03 to 1 μm.

In the case of a coating type magnetic layer, a magnetic paint is prepared by mixing and dispersing a magnetic powder with a binder resin, an organic solvent and other additives to prepare a magnetic paint. It is formed on the body by any method such as spraying or roll coating and drying, and is usually formed to a thickness of about 0.05 to 10 μm.

At this time, the magnetic powder used is γ
-Fe ₂ O ₃ , Fe ₃ O ₄ , γ-Fe ₂ O ₃ and Fe ₃ O
Iron oxide in the intermediate oxidation state with ₄ , Co-containing γ-Fe
Oxide-based magnetic powders such as ₂ O ₃ , Co-containing γ-Fe ₃ O ₄ , CrO ₂ , barium ferrite, Fe, Co, F
Various conventionally known magnetic powders such as metal magnetic powders such as e-Ni-Cr alloys and nitride-based magnetic powders such as iron nitride are widely used. In the case of acicular magnetic powders, average particle diameter (long axis) is used. It is preferable to use those having an average axis ratio (average long axis ratio / average short axis ratio) of usually about 0.05 to 1 μm and an average axis ratio (average short axis ratio) of about 5 to 10; .07
Those having a thickness of about 0.3 μm are preferably used.

Examples of the binder resin include, for example, vinyl chloride-vinyl acetate copolymers, cellulose resins, polyurethane resins, polyester resins, polyvinyl butyral resins, polyacrylic resins, and epoxy resins. As a binder resin for a magnetic recording medium, any of those generally used, such as a resin, a phenol resin, and a polyisocyanate compound, is preferably used.

Further, as the organic solvent, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone,
A solvent suitable for dissolving the binder resin to be used, such as ethyl acetate, benzene, toluene, xylene, tetrahydrofuran, dioxane, etc., is used alone or in combination of two or more without any particular limitation.

In the magnetic coating material, various commonly used additives such as an abrasive, an antistatic agent, a dispersant and a coloring agent may be optionally added.

In the case where the magnetic layer is formed only on one surface of the non-magnetic support having the magnetic layer formed on the surface, a back coat layer may be provided on the opposite surface. -A non-magnetic powder such as bon black and calcium carbonate is mixed and dispersed with a binder resin such as a vinyl chloride-vinyl acetate copolymer, a polyurethane resin, a cellulose resin, and an organic solvent to form a back coat layer. A coating composition is prepared by preparing a coating for use, applying the coating on the opposite side of the nonmagnetic support, and drying.

As the non-magnetic support, plastics such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide and polyvinyl chloride, aluminum alloys and titanium alloys are preferably used. . The non-magnetic support may be in any form such as a tape, a sheet, a disk, a card and the like, and may have a surface provided with projections.

As described above, the phosphoric acid derivative of the present invention can be favorably used for magnetic recording media. In addition to this, not only as a lubricating substance, but also as a coating resin (anticorrosive lining, non-adhesive coating, Weather-resistant paint), fiber treatment agent (water-repellent, oil-repellent), release agent, oil-resistant paper, leveling agent,
Adhesives, digesters, antifoam fibers (as sheath components),
It can also be used for optical lenses and medical polymer materials.

[0034]

Next, an embodiment of the present invention will be described. Example 1 To a solution of 1 mol of 6-perfluorohexylhexanol (manufactured by Daikin Fine Chemical Co., Ltd.) and 1 mol of triethylamine in 500 ml of tetrahydrofuran was added 2-chloro-
One mol of -1,3,2-dioxaphospholane (manufactured by Aldrich) was added, and the mixture was reacted at 25 ° C. for 6 hours. After the completion of the reaction, the hydrochloride of triethylamine was filtered off, and tetrahydrofuran was distilled off to obtain a phosphoric acid derivative represented by the following structural formula 9.

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Example 2 In Example 1, 6-perfluorohexylhexano-
In the same manner as in Example 1 except that 1 mol of 6-perfluoro-3-methylbutylhexanol (manufactured by Daikin Fine Chemical Co., Ltd.) was used instead of
The phosphoric acid derivative represented by was obtained.

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Example 3 In Example 1, 6-perfluorohexylhexano-
The phosphoric acid derivative represented by the following structural formula 11 was prepared in the same manner as in Example 1 except that 1 mol of 2-perfluorohexylethanol (manufactured by Daikin Fine Chemical Co., Ltd.) was used instead of toluene. Obtained.

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Example 4 In Example 1, 6-perfluorohexylhexano-
1H, 1H, 10H, 10H-perfluoro-1,10-decandiodiol (manufactured by Hydras Chemical Co., Ltd.)
A phosphoric acid derivative represented by the following structural formula 12 was obtained in the same manner as in Example 1 except that 5 mol was used.

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Example 5 2-Chloro-1,3,2-dioxaphor was added to a solution of 1 mol of 6-perfluorohexylhexanol and 1 mol of triethylamine in 500 ml of tetrahydrofuran.
1 mol of spholane-2-oxide (manufactured by Aldrich) was added and reacted at 25 ° C. for 6 hours. After the completion of the reaction, the hydrochloride of triethylamine was filtered off, and tetrahydrofuran was distilled off to obtain a phosphoric acid derivative represented by the following structural formula 13.

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Example 6 In Example 5, 6-perfluorohexylhexano-
In the same manner as in Example 5 except that 1 mol of 6-perfluoro-3-methylbutylhexanol was used instead of
A phosphoric acid derivative represented by the following structural formula 14 was obtained.

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Example 7 In Example 5, 6-perfluorohexylhexano-
A phosphoric acid derivative represented by the following structural formula 15 was obtained in the same manner as in Example 5, except that 1 mol of 2-perfluorohexylethanol was used instead of toluene.

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Example 8 In Example 5, 6-perfluorohexylhexano-
Except that 0.5 mol of 1H, 1H, 10H, 10H-perfluoro-1,10-decandiole was used in place of
In the same manner as in Example 5, a phosphoric acid derivative represented by the following structural formula 16 was obtained.

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Example 9 In Example 1, 6-perfluorohexylhexano-
Except that 1 mol of 1H, 1H-perfluoro-2,5,8-trimethyl-3,6,9-trioxaundecane-1-ol (manufactured by Hydras Chemical Co., Ltd.) was used in place of In the same manner as in Example 1, a phosphoric acid derivative represented by the following structural formula 17 was obtained.

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Example 10 In Example 1, 6-perfluorohexylhexano-
FOMBLIN Z DOL (Monte
The following structural formula 18 was prepared in the same manner as in Example 1 except that 0.5 mol of an average molecular weight of 2,000 was used.
The phosphoric acid derivative represented by was obtained.

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Example 11 In Example 1, 6-perfluorohexylhexano-
FOMBLIN Z DOL TX (Mo
A phosphoric acid derivative represented by the following structural formula 19 was obtained in the same manner as in Example 1 except that 0.5 mol of an average molecular weight of 2200 (manufactured by Netfluos) was used.

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Example 12 In Example 1, 6-perfluorohexylhexano-
The phosphoric acid derivative represented by the following structural formula 20 was prepared in the same manner as in Example 1 except that 1 mol of 1H, 1H-pentadecafluorooctylamine (manufactured by Daikin Fine Chemical Co., Ltd.) was used. Obtained.

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Example 13 In Example 1, 6-perfluorohexylhexano-
A phosphoric acid derivative represented by the following structural formula 21 was obtained in the same manner as in Example 1 except that 1 mol of stearyl alcohol was used in place of thiol alcohol.

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Example 14 To a solution of 1 mol of 2-perfluorohexylethanol and 1 mol of triethylamine in 500 ml of tetrahydrofuran was added:
1,2-Phenylene phosphoroch
1 mol of lorideite was added and reacted at 25 ° C. for 6 hours. After completion of the reaction, the hydrochloride of triethylamine was filtered off, and tetrahydrofuran was distilled off to obtain a phosphoric acid derivative represented by the following structural formula 22.

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Example 15 To a solution of 1 mol of 2-perfluorohexylhexanol and 1 mol of triethylamine in 500 ml of tetrahydrofuran was added 1,2-phenylene phosphoro.
1 mol of chloridate was added and reacted at 25 ° C. for 6 hours. After the completion of the reaction, the hydrochloride of triethylamine was filtered off, and tetrahydrofuran was distilled off to obtain a phosphoric acid derivative represented by the following structural formula 23.

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Example 16 In Example 4, 2-chloro-1,3,2-d
1,2-p instead of ioxaphospholane
henylenephosphorochloridi
A phosphoric acid derivative represented by the following structural formula 24 was obtained in the same manner as in Example 4 except that 1 mol of te (manufactured by Aldrich) was used.

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Example 17 In Example 4, 2-chloro-1,3,2-d
1,2-p instead of ioxaphospholane
henylenephosphorochlorida
A phosphoric acid derivative represented by the following structural formula 25 was obtained in the same manner as in Example 4 except that 1 mol of te (manufactured by Aldrich) was used.

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Examples 18 to 34 Co-Ni was obliquely incident-deposited on a 10 μm-thick polyethylene terephthalate film under an oxygen atmosphere to give a 0.055 μm-thick Co—Ni—O [Co: Ni ( (Weight ratio) = 80: 20], and then cut into 8 mm width.

Next, each of the phosphoric acid derivatives prepared in Examples 1 to 17 was mixed with a mixed solvent of isopropyl alcohol: methyl ethyl ketone: n-hexane = 1: 1: 5.
The ferromagnetic metal thin film layer was dissolved in each of the phosphoric acid derivative solutions at a concentration of 0.05% by weight, immersed in the respective phosphoric acid derivative solutions, dried, and placed on the ferromagnetic metal thin film layer as shown in Table 1 below. Films of the phosphoric acid derivatives obtained in Examples 1 to 17 were formed, and video tapes of Examples 18 to 34 were produced.

Examples 35 to 51 Co was obliquely incident-deposited on a 6 μm-thick polyethylene terephthalate film in an oxygen atmosphere to give a thickness of 0.0.
A ferromagnetic metal thin film layer of 55 μm Co—O is formed, and then the ferromagnetic metal thin film layer is formed by plasma polymerization using RF of 13.56 MHz, ethylene as a monomer gas, and hydrogen as a carrier gas. DLC (diamond-like carbon) with a thickness of 20 nm on the thin film layer
A protective film was formed and cut into a width of 8 mm.

Next, each of the phosphoric acid derivatives prepared in Examples 1 to 17 was mixed with a mixed solvent of isopropyl alcohol: methyl ethyl ketone: n-hexane = 1: 1: 5.
The ferromagnetic metal thin film layer on which the DLC protective film was formed was immersed in each of the phosphoric acid derivative solutions, dried, and dried on the DLC protective film. Films of the phosphoric acid derivatives obtained in Examples 1 to 17 shown in Table 1 were formed, and videotapes of Examples 35 to 51 were produced.

Examples 52 to 68 Using the phosphoric acid derivatives obtained in Examples 1 to 17 as lubricating substances, respectively, using α-Fe magnetic powder (coercive force 1500 oersted, saturation magnetization 100 parts by weight 120 emu / g) ) Vinyl chloride-vinyl acetate-vinyl alcohol copolymer 20 (VAGH, manufactured by UCC) Polyfunctional isocyanate compound 5 Carbon black (average particle size 0.024 μm) 3 α-Al ₂ O ₃ powder 3 {Myristic acid 2} A phosphoric acid derivative 2.5} cyclohexanone 150 {toluene 130} composition obtained in Examples 1 to 17 was dispersed in a ball mill for 72 hours to prepare a magnetic paint. Next, each magnetic paint was applied to a thickness of 15 μm.
m on a polyethylene terephthalate film having a thickness of 5 μm after drying, dried to form magnetic layers, calendered, and cut into 8 mm width. The videotapes of Examples 52 to 68 containing the phosphoric acid derivatives obtained in Examples 1 to 17 shown in FIG.
Was prepared.

[0056]

Comparative Example 1 A fluorinated ether compound having a hydroxyl group at one terminal of a molecule (F
OMBLIN Z DOL, manufactured by Montefluos, having an average molecular weight of 2,000) was dissolved in 1,1,2-trifluoro-1,2,2-trichloroethane at a concentration of 0.05% by weight to prepare a solution of a fluoride ether compound. did. Next, a film made of the fluorinated ether compound was formed on the ferromagnetic metal thin film layer in the same manner as in Example 18 using the obtained fluorinated ether compound solution to produce a videotape. .

Comparative Example 2 A fluorinated ether compound having a carboxyl group at one terminal of a molecule (FOMBLINZ DIAC, Monteflu)
os, 0.05% by weight to 1,1,2-trifluoro-1,2,2-trichloroethane.
By dissolving to a concentration, a solution of the fluorinated ether compound was prepared. Next, a film made of the fluorinated ether compound was formed on the ferromagnetic metal thin film layer in the same manner as in Example 18 using the obtained fluorinated ether compound solution.
Was prepared.

Comparative Example 3 Fluorinated ester compound having ester groups at both molecular terminals [F (CF ₂ ) ₆ CH ₂ CH ₂ OCO (CH ₂ ) ₁₇ H]
Was dissolved in n-hexane to a concentration of 0.05% by weight to prepare a fluorinated ester compound solution. Then, using the obtained fluorinated ester compound solution,
In the same manner as in Example 18, a film made of a fluorinated ester compound was formed on the ferromagnetic metal thin film layer to produce a video tape.

COMPARATIVE EXAMPLE 4 Using the fluorinated ether compound solution obtained in Comparative Example 1, a film made of the fluorinated ether compound was formed on the DLC protective film in the same manner as in Example 35. A videotape was prepared.

Comparative Example 5 Using the ether compound solution obtained in Comparative Example 2, a film made of the ether compound was formed on the DLC protective film in the same manner as in Example 35. A videotape was prepared.

Comparative Example 6 Using the fluorinated ester compound solution obtained in Comparative Example 3, a film made of the fluorinated ester compound was formed on the DLC protective film in the same manner as in Example 35, and a videotape was prepared. Produced.

Comparative Example 7 In the composition of the magnetic paint in Example 52, Example 5
A magnetic layer was formed in the same manner as in Example 52 except that the same amount of the fluoride ether compound used in Comparative Example 1 was used instead of the phosphoric acid derivative used in Example 2, and a video tape was produced. .

Comparative Example 8 In the composition of the magnetic paint in Example 52, Example 5
A magnetic layer was formed in the same manner as in Example 52, except that the same amount of the fluorinated ether compound used in Comparative Example 2 was used instead of the phosphoric acid derivative used in Comparative Example 2, and a video tape was produced. .

Comparative Example 9 In the composition of the magnetic paint in Example 52, Example 5
A magnetic layer was formed in the same manner as in Example 52 except that the same amount of the fluorinated ester compound used in Comparative Example 3 was used instead of the phosphoric acid derivative used in Example 2, and a video tape was produced.

The video tapes obtained in each of Examples and Comparative Examples were examined for still durability by the following method.

<Still Durability> An 8 mm VTR (EV-S90 manufactured by Sony Corporation) was used under the conditions of 20 ° C. and 50% RH using the video tape obtained in each of the examples and comparative examples.
Using 0), the still time until the reproduction output was reduced by 6 db from the initial value was measured. Table 2 below shows the results.

[0068]

From the results shown in Table 2 above, the phosphoric acid derivative used in the examples of the present invention has a still time equivalent to or longer than that of the conventional fluorine-based lubricating substance when used for video tape. This indicates that the video tape obtained by the present invention exhibits excellent lubricity.

[0070]

As is apparent from Table 2, the videotape obtained by the present invention shows excellent lubricity. From this, the lubricating substance comprising the phosphoric acid derivative of the present invention is: Good lubrication, high speed, low speed, high load,
A magnetic recording medium having excellent durability can be slid with low friction and low abrasion between two solids in contact with each other regardless of low load, and using a lubricating substance comprising a phosphoric acid derivative obtained by the present invention. Is obtained.

Claims (5)

[Claims] 1. A general formula of the following chemical formulas 1 to 8: Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image (Where R is a hydrocarbon group or a fluorocarbon group,
X is O or NR ₁ and R ₁ is hydrogen or a hydrocarbon group. A lubricating substance comprising any one of the phosphoric acid derivatives selected from the phosphoric acid derivatives represented by the formula (1). 2. A magnetic recording medium in which a magnetic layer is provided on one or both sides of a non-magnetic support, a general formula of the following formulas (1) to (8): ## STR1 ## (Where R is a hydrocarbon group or a fluorocarbon group, X is O or NR ₁ , and R ₁ is a hydrogen or hydrocarbon group) A magnetic recording medium characterized by using any phosphoric acid derivative selected from phosphoric acid derivatives represented by the formula (1) as a lubricating substance. 3. The magnetic material according to claim 2, wherein the magnetic layer is a ferromagnetic metal thin film layer, and a lubricating substance comprising a phosphoric acid derivative is applied on the ferromagnetic metal thin film layer in an amount of 0.5 to 20 mg / m ^2. recoding media. 4. The magnetic recording medium according to claim 3, wherein the ferromagnetic metal thin film layer is a ferromagnetic metal thin film layer provided with a protective film made of carbon, silicon oxide, zirconium oxide or chromium oxide on the surface. 5. The magnetic recording medium according to claim 2, wherein the magnetic layer is a coating type magnetic layer containing a magnetic powder, and the magnetic layer contains a lubricating substance comprising a phosphoric acid derivative in an amount of 10 to 100 mg / m ^2. .