JPH10306290A - Lubricant and magnetic recording medium using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lubricant for a magnetic recording medium capable of sliding a pair of solid bodies in contact with each other between them at low friction and with low abrasion, regardless of high speed, low speed, etc., by using a branched-type aliphatic diester of a specific molecular structure. SOLUTION: This lubricant is composed of (A) a branched-type aliphatic diester expressed by the formula [R<1> to R<6> are each a 1-18C hydrocarbon; R is a 6-18C fluorocarbon, a partially fluorinated carbon or hydrocarbon; A is a carbonyloxy; (n)=0-6], and preferably further (B) an aliphatic amine expressed by the formula R<7> N(R<8> )R<9> (R<7> is a 1-26C hydrocarbon; R<8> and R<9> are each a 1-20C hydrocarbon) (e.g. stearylamine) in an amount of 0.01-100 mol based on 1 mol of the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sliding between two solids with low friction and low abrasion regardless of high speed, low speed, high load and low load in all environments of high temperature, low temperature, high humidity and low humidity. The present invention relates to a lubricant to be moved and a magnetic recording medium using the lubricant which has excellent durability and running properties.

[0002]

2. Description of the Related Art Hardening of a solid surface and development of a lubricant have been carried out for the purpose of extending the service period of equipment and devices by sliding between two solids in contact with low friction and low wear. Particularly in the field of OA equipment, there is a strong demand for size reduction,
A precision mechanism is adopted for the sliding part year by year. In future equipment where precision parts slide continuously or intermittently in a wide range of environments, the friction and wear at the start, at the time of sliding or at the end of sliding will be reduced more than ever, and the load on the motor etc. will be reduced. Need to be reduced. For this reason, 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 lubricant is used as a lubricant.

A magnetic recording medium made by applying a magnetic paint containing a magnetic powder or a binder resin on a non-magnetic support and drying it runs in contact with a magnetic head or the like. The magnetic layer is required to have a small friction coefficient and excellent durability. further,
A ferromagnetic metal thin film type magnetic recording medium made by depositing a ferromagnetic metal or alloy on a non-magnetic support by vacuum evaporation or the like has a higher magnetic layer than the above-mentioned coating type magnetic recording medium. It is easy to measure coercive force and thin film, and it has excellent high density recording characteristics, but it does not use tough binder resin, and it has good surface smoothness of ferromagnetic metal thin film layer and protective film, so it can be used with magnetic head. When the coefficient of friction is large, it is susceptible to abrasion and damage, resulting in poor durability and running properties.

[0004] In particular, due to recent changes in the use environment, excellent stability is required in a wide temperature range from a low temperature to a high temperature, but this requirement cannot be sufficiently satisfied. Therefore, for example, in a magnetic recording medium, various lubricants such as an ester lubricant are made to exist on a ferromagnetic metal thin film (Japanese Patent Application Laid-Open Nos. 60-85427 and 62-8527).
236118, JP-A-2-210615, JP-A-4
JP-A-141821, JP-A-4-182924, JP-A-4-368621, JP-A-6-274858, etc.), and improving durability and running performance.

[0005]

However, in precision equipment in which the contact portion has been smoothed, low friction between two solids in contact with each other, regardless of high speed, low speed, high load, and low load, is still required.
A lubricant that slides with low wear has not been obtained, and it is impossible to avoid problems such as poor startup and accidental sudden increase in frictional force during sliding. In addition, in magnetic recording media, when various lubricants such as ester-based lubricants are present on the ferromagnetic metal thin film, a certain improvement effect of durability and running performance is recognized, but it cannot be said that it is sufficient. In particular, the durability and running performance under high temperature and high humidity are insufficient, and the magnetic head is liable to be stained or dropped out.

In view of the above circumstances, the present invention provides a low-friction, low-friction, low-speed, low-speed, high-load, low-load contact between two solids, regardless of the high-speed, low-speed, high-load, low-load precision equipment. The purpose is to obtain a lubricant that can be slid by wear. Another object of the present invention is to provide a magnetic recording medium which is excellent in durability and running properties and hardly causes problems such as contamination of a magnetic head by using the above-mentioned lubricant.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above object, and as a result, by using a branched aliphatic diester having a specific molecular structure, an aliphatic amine is added thereto. In addition, regardless of high speed, low speed, high load, and low load, the two solids in contact can be slid with low friction and low abrasion. The present inventors have found that a magnetic recording medium having excellent performance and running properties and hardly causing problems such as contamination of a magnetic head can be obtained, and have completed the present invention.

That is, the present invention provides the following general formula (1): R ¹ C (R ² ) (R ³ )-(CH ₂ ) n-A-RA- (CH ₂ ) n-CR ⁴ ( R ⁵ ) (R ⁶ ) (1) wherein R ^{1 to} R ⁶ are a hydrocarbon group having 1 to 18 carbon atoms;
Is a fluorinated carbon group having 6 to 18 carbon atoms, a partially fluorinated carbon group or a hydrocarbon group, and A is a carbonyloxy group (—COO
-), And n is an integer of 0 to 6].
To 3) and the above-mentioned branched aliphatic diester, together with the following general formula (2): R ⁷ N (R ⁸ ) R ⁹ (2) (wherein, R ⁷ is a hydrocarbon having 1 to 26 carbon atoms) Group, R ⁸ , R
⁹ is an aliphatic amine represented by a hydrocarbon group having 1 to 26 carbon atoms or hydrogen), a lubricant (claims 4 to 6), a nonmagnetic support, and at least a nonmagnetic support. In a magnetic recording medium having a magnetic layer on one side,
According to a seventh aspect of the present invention, there is provided a magnetic recording medium comprising the lubricant having the above-mentioned configuration inside or on the surface of a magnetic layer.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The branched aliphatic diester used in the present invention is represented by the following general formula (1): R ¹ C (R ² ) (R ³ )-(CH ₂ ) n-A-RA — (CH ₂ ) n —CR ⁴ (R ⁵ ) (R ⁶ ) (1) wherein R ^{1 to} R ⁶ are a hydrocarbon group having 1 to 18 carbon atoms;
Is a fluorinated carbon group having 6 to 18 carbon atoms, a partially fluorinated carbon group or a hydrocarbon group, and A is a carbonyloxy group (—COO
-), N is an integer of 0 to 6], and in particular, a long-chain fluorocarbon group, a partial fluorocarbon group or a hydrocarbon group which contributes to the improvement of lubricating property; It is characterized by having a branched hydrocarbon group that contributes to hydrolysis and solubility in general-purpose solvents, and two esters (carbonyloxy) that further contributes to improvement in adsorptivity to the protective surface.

In the conventional ester-based lubricant, OH ^- ions or H ₃ O ⁺ ions attack the carbonyl group of the ester under the influence of water to promote hydrolysis. In this case, since a high-branched hydrocarbon group is located close to a carbonyl group, steric hindrance is large, and ester bonds are hardly hydrolyzed even under high temperature and high humidity, and are chemically stable. As a result, when used for a magnetic recording medium, generation of altered substances that cause head contamination and dropout can be reduced. Further, since this type of branched aliphatic diester has two ester groups in the molecule, it can be stably adsorbed on the surface of the ferromagnetic metal thin film or the protective film and stably exist. As a result, even under a high load condition such as at the start of sliding, the lubricant can be stably present without being removed from the sliding surface, and good sliding characteristics can be exhibited.

Therefore, according to the branched aliphatic diester used in the present invention, regardless of high speed, low speed, high load, and low load, the two solids in contact can be slid with low friction and low wear. When it is used for a magnetic recording medium, it can be stably adsorbed on the surface of the magnetic layer or the surface of the protective film and can be stably present, or can be stably contained in the magnetic layer. Dirt and dropout of the magnetic head can be reduced, and the durability and running properties of the magnetic recording medium can be sufficiently improved.

In such a branched aliphatic diester, R in the general formula (1) consists of a carbon fluoride group having 6 to 18 carbon atoms, a partially fluorine-containing carbon group or a hydrocarbon group. It may be chain-like or branched, but is more preferably straight-chain. Also, the surface free energy
In order to reduce the oil content and obtain good lubricating properties, a fluorinated carbon group, particularly a partially fluorinated carbon group partially hydrogenated, is preferred. The number of carbon atoms is preferably 6 or more in order to obtain good lubricating properties. If the number of carbon atoms is too large, the viscosity of the lubricant increases.

The above-mentioned branched aliphatic diester is
As described above, the tertiary carbon has a tertiary carbon at a position close to the carbonyl group, and its steric hindrance can suppress hydrolysis under high temperature and high humidity. I can't. Therefore, the number of carbon atoms between the tertiary carbon and the carbonyl group, that is, n in the general formula (1) is 6
Hereinafter, it is particularly preferably 3 or less, and most preferably 0. Further, the hydrocarbon group bonded to the tertiary carbon, that is, R _{1 to} R ₆ in the general formula (1) are independent hydrocarbon groups, and each is a saturated or unsaturated, linear or branched, or cyclic hydrocarbon group. The carbon number may be any of 1 to 18. When such a hydrocarbon group is contained in the molecule, the compound becomes soluble in a low-cost general-purpose solvent and becomes easy to handle.

In such a branched aliphatic diester, when the total number of constituent carbons is 19 or less, the lubricant decreases due to evaporation, and the sliding characteristics at high temperatures or after high-temperature storage are insufficient. Is preferred, especially 24 or more,
It is better to be 130 or less. The total number of constituent carbons can be easily set by appropriately combining and selecting diester synthesis raw materials as described below.

The above-mentioned branched aliphatic diester used in the present invention may be synthesized by any method. Industrially effective synthetic methods include dialcohol
A method of obtaining a branched fatty acid diester by reacting about 2 mol of an acid chloride of a tertiary fatty acid with respect to 1 mol of a tertiary alcohol, and reacting about 2 mol of a tertiary alcohol with 1 mol of a dicarboxylic acid to obtain a branched alcohol diester. There is a way to get.

Examples of the above-mentioned dialcohol include 1H, 1H, 2 manufactured by EFTEK Co., Ltd. and Hydras Chemical Co., Ltd.
H, 3H, 3H-perfluorononane-1,2-dio
1H, 1H, 2H, 3H, 3H-perfluoroundecane-1,2-diol, 1H, 1H, 6H, 6H-
Perfluorohexane-1,6-diol, 1H, 1
H, 8H, 8H-perfluorooctane-1,8-diol, 1H, 1H, 10H, 10H-perfluorodecane-1,10-diol, 1H, 1H, 12H, 12H
-Perfluorododecane-1,12-diol, 2,2
-Bis (4-hydroxyphenyl) hexafluoropropane, "FOMBLINZ DO" manufactured by Ausimont
L ", 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol and the like.

The above-mentioned tertiary fatty acids are commercially available from Ciel Chemical Co., Ltd. under the trade names "Varsack 5", "Varsack 10", "Varsack 911", "Varsack 1516", Examples include "Equed 9" and "Equed 13" manufactured by Idemitsu Petrochemical Co., Ltd., and neodecanoic acid manufactured by Exxon. These tertiary fatty acids are 2-isopropyl-2,3-dimethylheptanoic acid, 2-ethyl-2,
3,3-trimethylbutanoic acid, 2,2,4,4-tetramethylpentanoic acid, 2,2,3,4-tetramethylpentanoic acid, 2,2,3,3-tetramethylpentanoic acid,
-Isopropyl-2,3,5,5-tetramethylhexanoic acid, 2,3,4-trimethyl-2-neopentylpentanoic acid, 2,2,4,4,6,6-hexamethylheptanoic acid, 2, It is a mixture of 4,4-trimethyl-2-tert-pentylpentanoic acid and 2-ethyl-2,3,3,5,5-pentamethylhexanoic acid.

Examples of the above dicarboxylic acid include perfluorosebacic acid, perfluoro-1,10-decanedicarboxylic acid, 1,8-octanedicarboxylic acid, and 1,10-decanedicarboxylic acid manufactured by Hydras Chemical Co., Ltd. Acid, 1,
And 12-dodecanedicarboxylic acid. Examples of the tertiary alcohol include 2-methyl-2-pentanole and 2-methyl-2-hexanol.

The aliphatic amine used in the present invention has the following general formula (2): R ⁷ N (R ⁸ ) R ⁹ (2) wherein R ⁷ is a hydrocarbon group having 1 to 26 carbon atoms. , R ⁸ , R
⁹ is a hydrocarbon group having 1 to 26 carbon atoms or hydrogen), and the total number of carbon atoms in R ⁷ , R ⁸ and R ⁹ is preferably 12 or more. Examples of such fatty acid amines include laurylamine, stearylamine, oleylamine, dilaurylamine, distearylamine, dioleylamine, phenyldodecylamine, N-methylstearylamine, N, N-dimethylstearylamine, tridodecyl Examples include amine, tridecylamine, and trioctylamine.

By using such an aliphatic amine in combination with the above-mentioned branched aliphatic diester, the sliding characteristics under high temperature and high humidity can be further improved.
The amount of the aliphatic amine to be used is preferably 0.01 to 100 mol, preferably 0.1 to 10 mol, per 1 mol of the branched aliphatic diester.

The lubricant of the present invention comprises, as an active ingredient, the above-mentioned branched aliphatic diester or a product obtained by adding the above-mentioned aliphatic amine to the above-mentioned branched aliphatic diester. If necessary, a lubricant other than these may be used in combination. Is also good. For example, fatty acids or metal salts thereof, aliphatic diesters, aliphatic amides, aliphatic alcohols, monosulfides, paraffins, silicones
General lubricants, such as carboxylic compounds, esters of aliphatic and fluorides, perfluoropolyethers, and polytetrafluoroethylene, can be used in combination. In this case, the general lubricant is used in an amount of 0.01 to 100 mol, preferably 0.1 to 10 mol, per 1 mol of the branched aliphatic diester.
It is good to be mole.

In using the lubricant of the present invention,
Where necessary, phosphorus-based extreme pressure agents such as trioleyl phosphate, sulfur-based extreme pressure agents such as benzyl disulfide, halogen-based extreme pressure agents such as allyl bromide, and organic metal-based agents such as zinc diisobutyldithiophosphate An extreme pressure agent or the like can be used in combination.

The magnetic recording medium of the present invention comprises a non-magnetic support and a magnetic layer on at least one side of the non-magnetic support, and the lubricant of the present invention having the above constitution is provided inside or on the surface of the magnetic layer. Features. Here, in order to provide the above-mentioned lubricant inside or on the surface of the magnetic layer, the above-mentioned lubricant is dissolved in a general-purpose organic solvent such as alcohol, hydrocarbon, ketone or ether, and this solution is used. The method may be carried out by applying or spraying on the magnetic layer formed on at least one surface of the non-magnetic support and drying, or conversely, immersing the magnetic layer in the above solution and drying.

As general-purpose organic solvents, n-hexane,
Heptane, octane, decane, dodecane, benzene, toluene, xylene, cyclohexane, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol
, Isopropanol, diethyl ether, tetrahydrofuran, cyclohexanone and the like.

When the magnetic layer is made of a ferromagnetic metal thin film, carbon (diamond or amorphous), silicon oxide, zirconium oxide, chromium oxide, and other organic compounds are formed on the thin film by vacuum deposition, sputtering, plasma, or the like. Alternatively, a protective film made of a material such as fluorine or silicon may be provided. Further, the ferromagnetic metal thin film may have a surface to which a small amount of moisture has adhered, or may have a rust preventive such as a benzotriazole type applied thereto.

The surface of a DLC (diamond-like carbon) protective film or the like may be subjected to oxygen or ammonia plasma treatment. By performing the plasma treatment, it is possible to deposit the chemically active species in the plasma while cleaning the surface of the protective film, and to allow the lubricant to be more stably present without reducing the hardness of the protective film. Become.
Further, the lubricant can be stably present by performing glow discharge treatment, ultraviolet irradiation treatment, heat treatment, and the like. These treatments may be performed before the lubricant is applied, or may be performed after the lubricant is applied. Further, after the lubricant is applied, the cleaning may be performed after washing the excess lubricant with a solvent or the like.

In the coating type magnetic recording medium, coating, spraying,
In addition to coating by immersion, etc., a lubricant is mixed in a magnetic paint using a general-purpose organic solvent, and this is applied on a non-magnetic support, and a magnetic coating film containing the lubricant together with the magnetic powder is formed. It may be formed. In addition, application, spraying,
The coating may be performed again by immersion or the like, and after the coating, excess lubricant or the like may be washed with a solvent. Further, a lubricant may be contained on the opposite side of the magnetic coating film, and the lubricant may be transferred to the magnetic coating film side.

The amount of the lubricant to be deposited on the ferromagnetic metal thin film is
The thickness is preferably in the range of 0.5 to 20 mg / m ² with respect to the surface of the thin film. The content of the lubricant in the magnetic coating film is 10 to 10
The range is preferably 0 mg / m ² . If the amount is too small, it is difficult to uniformly exist on the surface of the magnetic layer, and still durability cannot be sufficiently improved.If the amount is too large, inconveniences such as sticking of the magnetic head and the magnetic layer are caused, which is not preferable. . The amount and content of the lubricant to be applied can be determined, for example, by attaching or containing a lubricant, immersing the magnetic tape in a solvent overnight, extracting the lubricant with a solvent, and then performing gas chromatography or liquid chromatography. It can be obtained by a graph or the like.

In the magnetic recording medium of the present invention, the non-magnetic support includes a plastic such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyamide, polyimide, polyvinyl chloride, glass, aluminum or the like. Alloys, titanium alloys and the like are preferably used.
This non-magnetic support can be used for tape, sheet, disk, car,
And any form such as a pad, and a projection provided on the surface may be used.

In the ferromagnetic metal thin film type magnetic recording medium, Co, Ni, F
e, Co-Ni, Co-Cr, Co-P, Co-Ni-
P, Fe-Co-B, Fe-Co-Ni, Co-Ni-
Fe-B, Fe-Ni, Fe-Co, Co-Pt, Co
-Various ferromagnetic materials, such as -Ni-Pt or those to which oxygen is added, are formed into a thin film by a method such as vacuum evaporation, ion plating, sputtering, and plating. The thickness of the ferromagnetic metal thin film thus formed is
Usually, it is preferably in the range of 0.03 to 1 μm.

In a coating type magnetic recording medium, a magnetic paint containing a magnetic powder and a binder resin is applied to one or both surfaces of the nonmagnetic support, and the thickness is usually 0.05 to 10 μm.
m of magnetic layers are formed. The magnetic paint may optionally contain various conventionally known additives such as a filler, an antistatic agent, a dispersant, and a colorant.

The magnetic powder includes r-Fe ₂ O ₃ , Fe ₃ O
_4, r-Fe ₂ O ₃ and Fe ₃ iron oxide intermediate oxidation state between O _4, Co-containing r-Fe ₂ O _3, Co-containing r-Fe ₃ O
₄ , various conventionally known magnetic powders such as oxide magnetic powders such as CrO ₂ and barium ferrite, metal magnetic powders such as Fe, Co, and Fe—Ni—Cr alloys, and nitride magnetic powders such as iron nitride. Is widely used. In an acicular magnetic powder, the average particle diameter (major axis) is usually about 0.05 to 1 μm, and the average axis ratio (average major axis ratio / average minor axis ratio) is usually 5-1.
About 0 is preferably used. As the plate-like magnetic powder, those having an average major axis diameter of usually about 0.07 to 0.3 μm are preferably used.

Examples of the binder resin include vinyl chloride-vinyl acetate copolymers, cellulose resins, polyurethane resins, polyester resins, polyvinyl butyral resins, polyacrylic resins, and epoxy resins. Those commonly used as binder resins for magnetic recording media, such as phenolic resins and polyisocyanate compounds, are all suitably used.

In the magnetic recording medium of the present invention, if the magnetic layer is provided only on one surface of the non-magnetic support, a back coat layer may be provided on the other surface. The back coat layer is for a back coat layer containing a binder resin such as a vinyl chloride-vinyl acetate copolymer, a polyurethane resin and a cellulose resin together with a non-magnetic powder such as carbon black and calcium carbonate. It is formed by preparing a paint, applying it to the opposite side of the non-magnetic support, and drying.

[0035]

Next, an embodiment of the present invention will be described. Hereinafter, an example applied to a video tape will be described as a typical example, but the application, the manufacturing method, the substance, and the like are not limited to the following examples. The branched aliphatic diesters 1 to 8 used in each of the examples are the branched fatty acid diesters obtained in Production Examples 1 to 8 below.

Production Example 1 1.2 moles of "Vasic 10" and thionyl chloride 1.4
Were charged into an eggplant-shaped flask and reacted at 70 ° C. for 12 hours using benzene as a solvent. After cooling, vacuum distillation,
An acid chloride of "Barsack 10" was obtained. 1H,
1H, 10H, 10H-perfluorodecane-1,10
-0.4 mol of diol and 1 mol of pyridine in diethyl ether
To the ter solution, a diethyl ether solution of 1 mol of the above acid chloride was slowly added dropwise. After completion of the dropwise addition, the reaction was carried out at 40 ° C. for 24 hours. After cooling, diethyl ether as a solvent was distilled off. Thereafter, the resultant was washed with water and purified by distillation under reduced pressure to obtain a branched aliphatic diester 1.

With respect to the branched aliphatic diester 1,
Fourier Transform Infrared Spectrometer (Matson “P
I-1000 "), the result of infrared spectroscopy analysis,
The infrared spectrum shown in FIG. 1 was obtained. In the figure, a peak based on two ester bonds was observed at a wavelength of around 1740 cm ^-1 , and it was identified that the branched fatty acid diester had a structure represented by the general formula (1).

Production Example 2 An acid chloride of neodecanoic acid was obtained in the same manner as in Production Example 1 except that the same amount of neodecanoic acid was used instead of "Vasic 10". Further, a branched aliphatic diester 2 was obtained in the same manner as in Production Example 1 except that a 1 mol solution of this acid chloride in diethyl ether was used. Infrared spectroscopy was performed in the same manner as in Production Example 1, and it was confirmed that the branched fatty acid diester had the structure represented by the general formula (1).

Production Example 3 "Easid 13" was used instead of "Vasic 10"
Was prepared in the same manner as in Production Example 1 except that the same amount of was used to obtain an acid chloride of "Ecacid 13". Further, a branched aliphatic diester 3 was obtained in the same manner as in Production Example 1 except that a 1 mol solution of this acid chloride in diethyl ether was used. As a result of performing infrared spectroscopy analysis in the same manner as in Production Example 1, it was confirmed that the branched fatty acid diester had a structure represented by the general formula (1).

Production Example 4 1H, 1H, 10H, 10H-Perfluorodecane
Instead of 0.4 mol of 1,10-diol, 1H, 1H,
Branched aliphatic diester 4 was obtained in the same manner as in Production Example 1, except that the same amount of 12H, 12H-perfluorododecane-1,12-diol was used. Infrared spectroscopy was performed in the same manner as in Production Example 1, and it was confirmed that the branched fatty acid diester had the structure represented by the general formula (1).

Production Example 5 1H, 1H, 10H, 10H-Perfluorodecane
Instead of 0.4 mol of 1,10-diol, 1H, 1H,
Branched aliphatic diester 5 was obtained in the same manner as in Production Example 1 except that the same amount of 2H, 3H, 3H-perfluorononane-1,2-diol was used. As in Production Example 1,
Infrared spectroscopy was performed to confirm that the branched fatty acid diester had the structure represented by the general formula (1).

Production Example 6 1H, 1H, 10H, 10H-Perfluorodecane
Instead of 0.4 mol of 1,10-diol, 1H, 1H,
Branched aliphatic diester 6 was obtained in the same manner as in Production Example 1, except that the same amount of 2H, 3H, 3H-perfluorodecane-1,2-diol was used. As in Production Example 1,
Infrared spectroscopy was performed to confirm that the branched fatty acid diester had the structure represented by the general formula (1).

Production Example 7 1H, 1H, 10H, 10H-Perfluorodecane
Except that the same amount of 1,10-decanediol was used instead of 0.4 mol of 1,10-diol, and the reaction conditions after completion of the dropwise addition were changed from 24 hours at 40 ° C. to 24 hours at 60 ° C. Is a branched aliphatic diester 7 in the same manner as in Production Example 1.
I got As a result of performing infrared spectroscopy analysis in the same manner as in Production Example 1, it was confirmed that the branched fatty acid diester had a structure represented by the general formula (1).

Production Example 8 The procedure of Production Example 1 was repeated, except that the same amount of tert-butyl acetic acid was used in place of “Vasic 10”.
An acid chloride of -butyl acetic acid was obtained. The reaction conditions after the addition of 1 mol of this acid chloride in diethyl ether were changed from 40 hours to 60 ° C. at 40 ° C.
Except that was changed to 24 hours in the same manner as in Production Example 1.
Branched aliphatic diester 8 was obtained. As a result of performing infrared spectroscopy analysis in the same manner as in Production Example 1, it was confirmed that the branched fatty acid diester had a structure represented by the general formula (1).

Examples 1 to 14 Co was obliquely vapor-deposited on a 6 μm-thick polyethylene terephthalate film in an oxygen atmosphere to a thickness of 0.1 μm.
A 5 μm Co—O ferromagnetic metal thin film was formed.
Next, using 13.56 MHz RF (radio wave),
Using ethylene as a monomer gas and hydrogen as a carrier gas, a DLC (diamond-like carbon) protective film having a thickness of 20 nm was formed on the ferromagnetic metal thin film by a plasma polymerization method. Thereafter, the tape was cut into a tape width of 8 mm.

Next, the lubricants shown in Table 1 were respectively added to n
-Hexane: methyl ethyl ketone: isopropyl alcohol = 7: 2: 1 (weight ratio): 0.2% by weight (in the case where an aliphatic amine is used in combination, the aliphatic amine concentration is 0.1%).
(0.5% by weight), and the tape is immersed in this lubricant solution and then dried to produce 14 kinds of video tapes having a lubricant film on the DLC protective film. did.

Examples 15 to 28 Co-Ni was obliquely vapor-deposited on a 10 μm-thick polyethylene terephthalate film in an oxygen atmosphere to form a 0.15 μm-thick Co—Ni—O [Co: Ni (Weight ratio) = 80: 20]. Thereafter, the tape was cut into a tape width of 8 mm.

Next, the lubricants shown in Table 1 were respectively added to n
-Hexane: methyl ethyl ketone: isopropyl alcohol = 7: 2: 1 (weight ratio): 0.2% by weight (in the case where an aliphatic amine is used in combination, the aliphatic amine concentration is 0.1%).
(0.5% by weight), and the tape is immersed in the lubricant solution, and then dried to obtain 14 kinds of video tapes having a lubricant film on a ferromagnetic metal thin film. Produced.

Examples 29 to 42 100 parts by weight of α-Fe magnetic powder (coercive force 1,500 oersted, saturation magnetization 120 emu / g), vinyl chloride-vinyl acetate-vinyl alcohol copolymer (“V” manufactured by UCC)
AGH ") 20 parts by weight, polyfunctional isocyanate compound 5
A blended composition consisting of 3 parts by weight of carbon black, 3 parts by weight of carbon black, 3 parts by weight of α-Al ₂ O ₃ powder, ₂ parts by weight of myristic acid, 150 parts by weight of cyclohexanone and 130 parts by weight of toluene was placed in a ball mill for 72 hours. By mixing and dispersing, a magnetic paint was prepared. This magnetic paint was applied on a 15 μm thick polyethylene terephthalate film so that the thickness after drying was 5 μm, and then dried to form a magnetic layer. After calendering, it was cut to a tape width of 8 mm.

Next, the lubricants shown in Table 1 were respectively added to n
-Hexane: methyl ethyl ketone: isopropyl alcohol = 7: 2: 1 (weight ratio): 0.2% by weight (in the case where an aliphatic amine is used in combination, the aliphatic amine concentration is 0.1%).
(0.5% by weight), the tape was immersed in this lubricant solution, and then dried to produce 14 kinds of video tapes having a lubricant film on the magnetic layer. .

[0051]

Comparative Examples 1 to 3 In Comparative Example 1, 2-isopropyl-
1,3-Dimethylbutanoic acid-1,1-dihydroperfluorobutyl was added to a mixed solvent of n-hexane: methyl ethyl ketone: isopropyl alcohol = 7: 2: 1 (weight ratio) so as to have a concentration of 0.2% by weight. In Comparative Example 2, the dissolved lubricant solution was H (CH ₂ ) ₆ COOCH ₂ (CF ₂ ) ₈ CH ₂ OCO (CH ₂ ) ₆ H
Was dissolved in the same mixed solvent as described above to a concentration of 0.2% by weight. In Comparative Example 3, C ₉ H ₁₉ COOCH
₂ (CF ₂ ) ₂ CH ₂ OCOC ₉ H ₁₉ (C ₉ H ₁₉ is a branched isomer) dissolved in the same mixed solvent as above to a concentration of 0.2% by weight. Example 1
In the same manner as in No. 14, three types of videotapes having a lubricant film on the DLC protective film were produced.

Comparative Examples 4 to 6 In Comparative Example 1, 2-isopropyl-
1,3-Dimethylbutanoic acid-1,1-dihydroperfluorobutyl was added to a mixed solvent of n-hexane: methyl ethyl ketone: isopropyl alcohol = 7: 2: 1 (weight ratio) so as to have a concentration of 0.2% by weight. In Comparative Example 2, the dissolved lubricant solution was H (CH ₂ ) ₆ COOCH ₂ (CF ₂ ) ₈ CH ₂ OCO (CH ₂ ) ₆ H
Was dissolved in the same mixed solvent as described above to a concentration of 0.2% by weight. In Comparative Example 3, C ₉ H ₁₉ COOCH
₂ (CF ₂ ) ₂ CH ₂ OCOC ₉ H ₁₉ (C ₉ H ₁₉ is a branched isomer) dissolved in the same mixed solvent as above to a concentration of 0.2% by weight. Example 15 except that
28, three kinds of videotapes having a lubricant film on a ferromagnetic metal thin film were produced.

Comparative Examples 7 to 9 In Comparative Example 1, 2-isopropyl-
1,3-Dimethylbutanoic acid-1,1-dihydroperfluorobutyl was added to a mixed solvent of n-hexane: methyl ethyl ketone: isopropyl alcohol = 7: 2: 1 (weight ratio) so as to have a concentration of 0.2% by weight. In Comparative Example 2, the dissolved lubricant solution was H (CH ₂ ) ₆ COOCH ₂ (CF ₂ ) ₈ CH ₂ OCO (CH ₂ ) ₆ H
Was dissolved in the same mixed solvent as described above to a concentration of 0.2% by weight. In Comparative Example 3, C ₉ H ₁₉ COOCH
₂ (CF ₂ ) ₂ CH ₂ OCOC ₉ H ₁₉ (C ₉ H ₁₉ is a branched isomer) dissolved in the same mixed solvent as above to a concentration of 0.2% by weight. Example 29 except that
In the same manner as in Nos. To 42, three types of videotapes having a lubricant film on the magnetic film were produced.

The above Examples 1-42 and Comparative Examples 1-9
For each of the video tapes, still durability, coefficient of friction and head contamination were examined by the following methods. These results are shown in Table 2 below (Examples 1 to 14 and Comparative Examples 1 to
3), Table 3 (Examples 15 to 28 and Comparative Examples 4 to 6),
The results were as shown in Table 4 (Examples 29 to 42 and Comparative Examples 7 to 9).

<Still durability> A video tape was heated at 60 ° C.
After storing for 168 hours in an atmosphere of 80% RH,
In an atmosphere of 50 ° C. and 50% RH, the tape was set at a winding angle of 220 ° around a 4 mm diameter cylinder for 8 mm, the relative speed between the tape and the magnetic head was 11.3 m / sec, and the tape tension was 12.5 g.
A sine wave having a wavelength of 1.6 μm was recorded under the condition of f / cm, and the reproduction output was measured in the still mode. The time (minute) until the reproduction output decreased by 1/2 from the initial value was evaluated as still durability (still life).

<Coefficient of friction>
After storing for 168 hours in an atmosphere of% RH,
Under 50% RH atmosphere, sliding speed 1m / min, sliding speed 5
Under a condition of cm and a tape tension of 20 g, a reciprocal sliding test was performed on the stainless steel pin for 20 reciprocations, and a friction coefficient at the 20th reciprocation was determined.

<Head dirt> The video tape is kept at 60 ° C. for 8 hours.
After storing for 168 hours in an atmosphere of 0% RH, 50 m of this videotape was subjected to 8 mm VTR [EV-S90 manufactured by Sony Corporation under an atmosphere of 20 ° C. and 50% RH.
0 "], and the magnetic head was stained with a microscope for 100 times. A sample without head dirt was evaluated as ○, a sample with slight head dirt was evaluated as Δ, and a sample with much head dirt was evaluated as ×.

[0059]

[0060]

[0061]

From the results shown in Tables 2 to 4, each of the videotapes of Examples 1 to 42 using the branched aliphatic diester of the present invention or a lubricant comprising the branched aliphatic diester and an aliphatic amine was stored at a high temperature. The coefficient of friction after was low, and the corresponding Comparative Examples 1 to
Compared to the video tape of No. 9, it has a better still life after high-temperature storage, and has less head dirt.
It can be seen that the durability and running performance are remarkably excellent. Although the above embodiment shows an example in which the present invention is applied to a video tape, the same effect can be obtained when the present invention is applied to other magnetic recording media such as a hard disk and a floppy disk.

[0063]

As described above, according to the present invention, by using a specific branched aliphatic diester or an aliphatic amine with the same, regardless of the high speed, low speed, high load, or low load, the present invention provides A lubricant capable of sliding between solids with low friction and low wear can be provided. Also, by using this lubricant, it is possible to provide a magnetic recording medium that can maintain excellent lubricating properties even under high temperature and high humidity, has excellent durability and running properties, and does not cause problems such as contamination of a magnetic head. it can.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing an infrared spectrum of a branched aliphatic diester 1 obtained in Production Example 1 as an example of a branched aliphatic diester used in the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // (C10M 111/02 105: 54 105: 60) C10N 30:08 40:18 50:02

Claims (10)

[Claims] 1. The following general formula (1): R ¹ C (R ² ) (R ³ )-(CH ₂ ) n-A-RA- (CH ₂ ) n-CR ⁴ (R ⁵ ) ( R ⁶ ) (1) wherein R ^{1 to} R ⁶ are a hydrocarbon group having 1 to 18 carbon atoms;
Is a fluorinated carbon group having 6 to 18 carbon atoms, a partially fluorinated carbon group or a hydrocarbon group, and A is a carbonyloxy group (—COO
-), N is an integer of 0 to 6]. 2. The lubricant according to claim 1, wherein in the branched aliphatic diester, R in the general formula (1) is linear. 3. The lubricant according to claim 1, wherein the branched aliphatic diester has a total carbon number of 20 or more. 4. A with branched aliphatic diester of any one of claims 1 to 3, the general formula of the following ^{(2); R 7 N (} R 8) R 9 ... (2) ( wherein, R ⁷ Is a hydrocarbon group having 1 to 26 carbon atoms, R ⁸ and R
⁹ is a hydrocarbon group having 1 to 26 carbon atoms or hydrogen). 5. An aliphatic amine having a total carbon number of 12
The lubricant according to claim 4, which is the above. 6. The lubricant according to claim 4, wherein the content of the aliphatic amine is 0.01 to 100 mol per 1 mol of the branched aliphatic diester. 7. A magnetic recording medium having a non-magnetic support and a magnetic layer on at least one surface of the non-magnetic support, wherein the lubricant according to claim 1 is provided inside or on the surface of the magnetic layer. Magnetic recording medium. 8. The magnetic recording medium according to claim 7, wherein the magnetic layer is formed of a ferromagnetic metal thin film, and the amount of the lubricant applied to the surface of the thin film is 0.5 to 20 mg / m ² . 9. The magnetic recording medium according to claim 8, further comprising a protective film mainly composed of at least one selected from carbon, silicon oxide, zirconium oxide and chromium oxide on the surface of the ferromagnetic metal thin film. 10. The magnetic layer comprises a magnetic coating film containing a magnetic powder, and the content of the lubricant in the coating film is 10 to 100 mg / mg.
The magnetic recording medium according to claim 7 is m ^2.