JPH0793745A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To synthesize a novel lubricant capable of exhibiting satisfactory lubricating performance when used in a metallic thin film type magnetic recording medium and to improve durability and running performance. CONSTITUTION:A lubricant obtd. by adding a compd. having a long chain alkyl group to a compd. having a perfluoro-polyether skeleton is held on the surface of the magnetic layer of a metallic thin film type magnetic recording medium. The lubricant is concretely obtd., e.g. by adding a long chain hydrocarbon compd. having an amino group in each molecule to perfluoro-polyether having an oxyalkylene group terminated by hydroxyl groups.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium such as a magnetic tape or a magnetic disk, and more particularly to improvement of a lubricant retained on the surface of a magnetic layer.

[0002]

2. Description of the Related Art Conventionally, as a magnetic recording medium such as an 8 mm VTR tape or a magnetic disk used as a storage medium for a hard disk device, a ferromagnetic metal material is deposited on a non-magnetic support by a method such as vapor deposition. A so-called metal thin film type magnetic recording medium having this as a magnetic layer is used.

In this metal thin film type magnetic recording medium, since the smoothness of the magnetic layer surface is extremely good, the substantial contact area with a sliding member such as a magnetic head or a guide roller is increased, and the friction coefficient is increased. As a result, an adhesion phenomenon (so-called sticking) easily occurs. As a result, as described below, there are many problems in terms of running property and durability.

For example, regarding an 8 mm VTR tape, when this kind of magnetic tape is inserted into an 8 mm video deck, it is wound around a drum by passing through 10 or more guide pins, in which case a pinch roller and a capstan are used. Keeps the tape tension and tape running speed constant (for example, the tape tension is about 20g,
The tape running speed is 0.5 cm / sec. ).

In such a running system, the magnetic layer of the magnetic tape is in contact with a fixed guide pin made of stainless steel, and when the friction on the tape surface becomes large, the tape causes stick-slip, The phenomenon of so-called “tape noise” occurs, and the playback screen becomes tight. Further, the relative speed between the magnetic tape and the magnetic head is very large, and particularly in the pause state, the same portion of the tape is exposed to the contact state at high speed running,
The magnetic layer is heavily worn, resulting in a reduction in reproduction output. Such a problem becomes more serious when a vapor deposition tape is used as the magnetic tape because the magnetic layer of the tape is extremely thin.

In the hard disk device, the magnetic head and the disk are in contact with each other before the rotation (CSS;
The magnetic head is floated by an air flow generated at the time of contact start / stop) and high speed rotation start. Therefore, the magnetic head rubs against the surface of the disk at the time of starting or stopping or starting, and the increase in friction at that time is a serious problem. Generally, in order to secure the reliability at the product level, the above-mentioned CS
It is desired that the friction coefficient after S operation is performed 20,000 times is 0.5 or less, and it is a subject to realize a sufficient CSS characteristic. Further, since the magnetic head and disk are rotated at a high speed, head crash due to the magnetic head and the disk is also an important problem in the thin film medium.

To solve such problems, it has been studied to use a lubricant in a magnetic recording medium. For example, a higher fatty acid or its ester is top-coated on the surface of the magnetic layer of the magnetic recording medium. Attempts have been made to reduce the coefficient of friction.

Here, the lubricant used for the magnetic recording medium is (1) excellent in low temperature characteristics so as to ensure a predetermined lubricating effect when used in cold regions, and (2) with a magnetic head. Spacing is a problem, so it can be applied very thinly, and even in that case sufficient lubrication characteristics can be exhibited. (3) It can withstand a long time or use for a long time.
Very strict characteristics are required in terms of its properties, such as the continued lubrication effect.

In addition to the characteristics required for the lubricant itself, there are also conditions such as good lubricating performance with the head when applied to the medium, uniform and strong adhesion to the medium, and long-term retention of these performances. It is desired to be satisfied. That is, it is necessary for the above-mentioned lubricant to satisfy the various requirements as described above even when the lubricant is applied to a film thickness of about several nanometers at a substantially monomolecular level.

[0010]

The lubrication performance of the lubricant is
Although it has been shown to depend on its molecular structure,
In particular, compounds used as lubricants for magnetic recording media are roughly classified into three types: silicon-based, hydrocarbon-based, and fluorinated carbon-based compounds.

Silicon-based lubricants are widely used in the field of so-called coating type magnetic recording media because of their good thermal stability and low vapor pressure. However, when it is applied to the metal thin film type magnetic recording medium having a very good surface property as described above, good lubrication performance cannot be obtained, and the lubrication performance in the pin-on-disk wear acceleration test or CSS test is not obtained. Is not durable enough to meet specifications. Therefore, with this silicon-based lubricant, it is extremely difficult to form the lubrication film oriented on the medium surface of the metal thin film type magnetic recording medium, which is currently the mainstream of magnetic recording medium, and to realize the required lubricating characteristics. Difficult to do.

Hydrocarbon lubricants are currently the mainstream lubricants in the field of coating type magnetic recording media. However, this hydrocarbon-based lubricant is inferior to the above-mentioned silicon-based lubricant and fluorinated carbon-based lubricant in terms of thermal or chemical stability, and a frictional polymer formed by reaction of molecules by friction is concerned. It is easily generated in a system that uses a hydrocarbon lubricant. This frictional polymer deteriorates the lubrication characteristics and sometimes causes fatal failure. Furthermore, this hydrocarbon-based lubricant has the drawback of having a high vapor pressure. Therefore, the above-mentioned metal thin film type magnetic recording medium cannot replenish the lubricant and thus exhibits excellent friction characteristics, but on the other hand, it is difficult to be used in practice because of its high vapor pressure.

On the other hand, the fluorinated carbon type lubricant is the most used lubricant at present in the field of the metal thin film type magnetic recording medium. Among them, perfluoropolyether is widely used because it has excellent lubricating performance and surface protection action as compared with other fluorinated carbon materials. This is because, since the CF ₂ —O—CF ₂ ether bond is flexible, the viscosity is low when the molecular weights are the same, and the viscosity does not change in a wide temperature range. In addition to these reasons, chemically inert, low vapor pressure, high thermal or chemical stability, low surface energy, good boundary lubrication characteristics, and It also has good water-repellency.

The properties of perfluoropolyethers as mentioned above depend very strongly on their molecular structure. Several types of perfluoropolyether are commercially available, and they differ in molecular weight, main chain repeating unit, and terminal group.

For example, the Fomblin-Y type is CF
(CF ₃₎ is a random polymer of CF ₂ O and CF ₂ O, whereas the recurring units of the main chain has a branched structure, Fomblin -Z type, CF ₂ CF ₂ O and C
It is a polymer of F ₂ O and has a linear structure. Also, Demnu
The m type and the Krytox type are homopolymers of hexafluoropropylene oxide and hexafluoroisopropylene oxide, respectively.

However, since these perfluoropolyethers are chemically inactive, they lack adsorption ability on the surface of the magnetic recording medium. Therefore, for the purpose of improving the adsorptive power, fomblin Z-DOL (hydroxyl group) and fomblin AM2001 (piperonyl group), which are perfluoropolyethers having polar groups at both ends, have been developed. For example, in Fomblin AM2001, a very strong immobilization effect is obtained especially on a metal surface or a carbon surface, and the coefficient of friction is reduced by introducing a polar group at the end, and as a result, the service life of the magnetic disk can be improved. .

However, the demand for the lubricant used in the above-mentioned metal thin film type magnetic recording medium is very strict,
Although various measures have been taken, there is still no lubricant that sufficiently satisfies the required properties.

Further, in a magnetic recording system having a relative velocity exceeding several meters, the frictional heat generated at the contact portion causes the surface temperature of the medium to rise rapidly, albeit instantaneously. At this time, the temperature at the contact point between the magnetic head and the medium cannot be measured accurately, but it is said that the temperature exceeds several hundred degrees in the evaluation by calculation.

Under such a boundary lubrication condition, since a reactive surface appears, the decomposition reaction of the lubricant molecules is promoted by the temperature rise at the contact point. Although perfluoropolyether is stable in air at a temperature of 350 ° C. or higher, it is a metal alloy (eg, iron or titanium alloy), or a Lewis acid or Lewis base (eg, AlCl ₃ , FeF ₃ , A).
In the presence of 1 ₂ O ₃ ), it easily decomposes. This decomposition of the lubricant molecules adversely affects the lubrication properties and thus reduces the reliability of the magnetic recording system. Therefore, it is considered that not only the above-mentioned lubrication characteristics but also that the decomposition of lubricant molecules is small in the lubricant.

Further, perfluoropolyethers are only dissolved in CFCs, which is a global environmental problem.

Therefore, the present invention provides a magnetic recording medium having a sufficient reliability by developing a lubricant excellent in thermal or chemical stability and adsorption to the medium surface. The purpose is to do.

[0022]

Means for Solving the Problems In the present invention, as a result of earnestly researching what does not achieve the above-mentioned object, a novel compound in which a compound having a long-chain hydrocarbon is added to a compound having a perfluoropolyether skeleton By synthesizing such a lubricant and using this lubricant in a metal thin film type magnetic recording medium, it is possible to exhibit good lubrication performance, and it is possible to improve durability and runnability, The present invention has been completed.

That is, the magnetic recording medium according to the first invention of the present application is a magnetic recording medium having at least a magnetic layer on a non-magnetic support, wherein the surface of the magnetic layer has hydroxyl groups at the ends. It is characterized in that it holds a lubricant obtained by adding a long-chain hydrocarbon compound having an amino group in the molecule to a perfluoropolyether having an oxyalkylene group.

The magnetic recording medium according to the second invention of the present application is a magnetic recording medium having at least a magnetic layer on a non-magnetic support, and the end of the magnetic layer is a hydroxyl group. The present invention is characterized in that a long-chain carboxylic acid ester of perfluoropolyether having an oxyalkylene group is added with a long-chain hydrocarbon compound having an amino group in the molecule to carry a lubricant.

Further, the magnetic recording medium according to the third invention of the present application is a magnetic recording medium having at least a magnetic layer on a non-magnetic support, and has a carboxyl group at the end on the surface of the magnetic layer. It is characterized in that it holds a lubricant prepared by adding an amino acid ester to perfluoropolyether. A magnetic recording medium according to a fourth invention of the present application is a magnetic recording medium having at least a magnetic layer on a non-magnetic support, and comprises a perfluoropolyether having a carboxyl group at the end on the surface of the magnetic layer. It is characterized in that it has a lubricant in which an amino acid ester is added to a long-chain alkyl ester.

The magnetic recording medium according to the fifth aspect of the present invention is a magnetic recording medium having at least a magnetic layer on a non-magnetic support, and the magnetic layer surface is a perfluoropolymer having a hydroxyl group at the terminal. It is characterized in that it has a lubricant obtained by adding an amino acid ester to a long-chain alkyl ester of ether. The magnetic recording medium according to the sixth invention of the present application is a magnetic recording medium having at least a magnetic layer on a non-magnetic support, and the perfluoropolyether derivative having a phosphoric acid group at the terminal on the surface of the magnetic layer. In addition, a lubricant containing a long-chain hydrocarbon having an amino group in the molecule is retained.

In the first invention of the present application, the terminal is a hydroxyl group.
Perfluoropo having an oxyalkylene group
As the polyether, monofunctional and polyfunctional perfluoro
Polyethers can be used, eg Montefluos
Fomblin HO (CH₂CH ₂O) nCH₂CF₂O (CF₂CF₂O) p (CF
₂O) qCF₂CH₂(OCH₂CH₂) nOH etc., but not limited to
It is not something that will be done.

Although the molecular weight of the above-mentioned perfluoropolyether is not particularly limited, it is preferably in the range of about 600 to 5,000. If the molecular weight is too large, the effect of the adsorbing group will be small, and if it is small, the effect of fluorine will be weakened.

On the other hand, the long-chain hydrocarbon compound having an amino group in the molecule is represented by the following chemical formula 17. This long-chain hydrocarbon compound has 6 or more and 30 or less carbon atoms, and any compound selected regardless of a branched structure, an unsaturated bond, an isomer structure, or an alicyclic structure can be used. It is preferably a straight chain having 10 to 22 carbon atoms.
When the carbon number is small, the effect is small, and when the carbon number is large, the solubility is small, so that it becomes uncommon. Specific examples of the long-chain hydrocarbon compound include compounds having the structures shown in Table 1 below. Among the above long-chain hydrocarbon compounds, a trialkylamine in which all hydrogens in the amino group are replaced with alkyl groups is preferable.

[0030]

[Chemical 17]

[0031]

[Table 1]

In the first invention of the present application, the perfluoropolyether having an oxyalkylene group having a hydroxyl group at the terminal is lubricated by adding a long chain hydrocarbon compound having an amino group in the molecule. Used as an agent.

Here, the addition amount of the long-chain hydrocarbon compound is preferably in the range of 0.01 to 100 in terms of molar ratio. By setting the addition amount of the long-chain hydrocarbon compound within the above range, it is possible to obtain good results without deteriorating the friction coefficient even under various usage conditions.

In the second invention of the present application, the perfluoropolyether having a carboxyl group at the terminal is represented by the following chemical formula 1.
It is represented by the general formula shown in Chemical formula 8 or Chemical formula 19 and may be monofunctional or polyfunctional. As the perfluoropolyether having a carboxyl group at the terminal, specifically, compounds having a structure shown in Table 2 below can be used, but the compounds are not limited thereto.

[0035]

[Chemical 18]

[0036]

[Chemical 19]

[0037]

[Table 2]

In the chemical structural formula of perfluoropolyether shown in Table 2 above, j, m, n,
p and q represent an integer of 1 or more. The molecular weight is not particularly limited, but is preferably about 600 to 5000.
The effect of the terminal group becomes too large, the effect becomes small,
If it is small, the effect of the perfluoropolyether group is diminished.

On the other hand, the amino acid ester is represented by the general formula shown in Chemical Formula 20 or Chemical Formula 21 below. As the amino acid ester, the alkyl group has a branched structure, an unsaturated bond,
Any compound selected regardless of its isomer structure or alicyclic structure can be used, but more preferably it has 10 or more carbon atoms. When the number of carbon atoms is less than 10, inconvenience occurs in consideration of solubility. Specifically, Table 3 below
Examples thereof include compounds having the structure shown in.

[0040]

[Chemical 20]

[0041]

[Chemical 21]

[0042]

[Table 3]

In the second invention of the present application, a lubricant obtained by adding the above amino acid ester to the perfluoropolyether having a carboxyl group at the terminal is used as a lubricant. Here, the amount of the amino acid ester added is preferably in the range of 0.01 to 100 in molar ratio with respect to the carboxyl group of the perfluoropolyether.
By setting the addition amount of the above-mentioned amino acid ester within the above range, it is possible to obtain good results without deteriorating the friction coefficient even under various usage conditions.

By adding this amino acid ester, it becomes possible to eliminate the amount of the CFC-based solvent used as the thinner during coating.

In the third invention of the present application, both monofunctional and polyfunctional ones can be used as the long-chain carboxylic acid ester of perfluoropolyether having an oxyalkylene group having a hydroxyl group at the terminal. . The molecular weight of the long-chain carboxylic acid ester of the perfluoropolyether is not particularly limited, but is preferably in the range of 600 to 5000. If the molecular weight is too large, the effect of the adsorbing group will be small, and if it is small, the effect of fluorine will be weakened.

On the other hand, the long-chain hydrocarbon compound having an amino group in the molecule is represented by the general formula shown below. This long-chain hydrocarbon compound has 6 or more and 30 or less carbon atoms, and any compound selected regardless of a branched structure, an unsaturated bond, an isomer structure, or an alicyclic structure can be used. It is preferably a straight chain having 10 to 22 carbon atoms. When the carbon number is small, the effect is small, and when the carbon number is large, the solubility is small, so that it becomes uncommon. Among the long-chain hydrocarbon compounds, trialkylamine in which all hydrogens in the amino group are replaced with alkyl groups is preferable.

[0047]

[Chemical formula 22]

In the third invention of the present application, the long-chain hydrocarbon compound having the amino group is added to the long-chain carboxylic acid ester of perfluoropolyether having the oxyalkylene group having a hydroxyl group at the terminal. Is used as a lubricant. Here, the amount of the long-chain hydrocarbon compound added is preferably in the range of 0.01 to 100 in terms of molar ratio. By setting the addition amount of the long-chain hydrocarbon compound within the above range, it is possible to obtain good results without deteriorating the friction coefficient even under various usage conditions.

In the fourth invention of the present application, the long-chain alkyl ester of perfluoropolyether having a carboxyl group at the terminal is represented by the following general formula (23) or (24) and may be monofunctional or polyfunctional. . As the long-chain alkyl ester of perfluoropolyether having a carboxyl group at the terminal, specifically, any compound having a structure shown in Table 4 below can be used, but the invention is not limited thereto. .

[0050]

[Chemical formula 23]

[0051]

[Chemical formula 24]

[0052]

[Table 4]

In the chemical structural formula of the long-chain alkyl ester of perfluoropolyether shown in Table 4 above, j, m, n, p, and q are integers of 1 or more. The molecular weight is not particularly limited, but is 600 to 50.
About 00 is preferable. If the molecular weight becomes too large, the effect of the terminal group becomes small, and if it is too small, the effect of the perfluoropolyether group becomes weak.

By using a long-chain alkyl ester of perfluoropolyether, it becomes possible to eliminate the amount of the CFC-based solvent used as a thinner during coating.

On the other hand, the amino acid ester is represented by the general formula shown in Chemical formula 25 or 26 below. As the amino acid ester, the alkyl group has a branched structure, an unsaturated bond,
Any compound selected regardless of its isomer structure or alicyclic structure can be used, but more preferably it has 10 or more carbon atoms. When the number of carbon atoms is less than 10, inconvenience occurs in consideration of solubility. Specifically, Table 5 below
Examples thereof include compounds having the structure shown in.

[0056]

[Chemical 25]

[0057]

[Chemical formula 26]

[0058]

[Table 5]

In the fourth invention of the present application, a lubricant obtained by adding the above-mentioned amino acid ester to the long-chain alkyl ester of perfluoropolyether having a carboxyl group at the terminal is used as a lubricant. Here, the amount of the amino acid ester added is preferably in the range of 0.01 to 100 in terms of molar ratio. By setting the addition amount of the above-mentioned amino acid ester within the above range, it is possible to obtain good results without deteriorating the friction coefficient even under various usage conditions.

In the fifth invention of the present application, the long-chain alkyl ester of perfluoropolyether having a hydroxyl group at the terminal is represented by the general formula shown in Chemical formula 27 or Chemical formula 28 below, and may be monofunctional or polyfunctional. As a long-chain alkyl ester of perfluoropolyether having a hydroxyl group at this end,
Specifically, any of the compounds having the structures shown in Table 6 below can be used, but the compounds are not limited thereto.

[0061]

[Chemical 27]

[0062]

[Chemical 28]

[0063]

[Table 6]

In the chemical structural formula of the long-chain alkyl ester of perfluoropolyether shown in Table 6 above, j, m, n, p, and q are integers of 1 or more. The molecular weight is not particularly limited, but is 600 to 50.
About 00 is preferable. If the molecular weight becomes too large, the effect of the terminal group becomes small, and if it is too small, the effect of the perfluoropolyether group becomes weak.

On the other hand, the amino acid ester is represented by the general formula shown in Chemical formula 29 or 30 below. As the amino acid ester, the alkyl group has a branched structure, an unsaturated bond,
Any compound selected regardless of its isomer structure or alicyclic structure can be used, but more preferably it has 10 or more carbon atoms. When the number of carbon atoms is less than 10, inconvenience occurs in consideration of solubility. Specifically, Table 7 below
Examples thereof include compounds having the structure shown in.

[0066]

[Chemical 29]

[0067]

[Chemical 30]

[0068]

[Table 7]

In the fifth invention of the present application, a lubricant obtained by adding the above-mentioned amino acid ester to the long-chain alkyl ester of perfluoropolyether having a hydroxyl group at the terminal is used as a lubricant. Here, the amount of the amino acid ester added is preferably in the range of 0.01 to 100 in terms of molar ratio. By setting the addition amount of the above-mentioned amino acid ester within the above range, it is possible to obtain good results without deteriorating the friction coefficient even under various usage conditions.

By adding this amino acid ester, it becomes possible to eliminate the amount of the CFC-based solvent used as the thinner during coating.

In the sixth invention of the present application, the perfluoropolyether derivative having a phosphoric acid group at the terminal is represented by the following chemical formula 31
It is represented by the general formula shown below and may be monofunctional or polyfunctional. As the perfluoropolyether group of the perfluoropolyether derivative having a phosphoric acid group at the terminal, those having a structure shown in the following Table 8 can be specifically used, but are not limited thereto. is not.

[0072]

[Chemical 31]

[0073]

[Table 8]

In the chemical structural formula of the perfluoropolyether group shown in Table 8 above, j, m, n,
k, p, and q represent an integer of 1 or more. The molecular weight is not particularly limited, but is preferably about 600 to 5000. If the molecular weight becomes too large, the effect of the terminal group becomes small, and if it is too small, the effect of the perfluoropolyether group becomes weak.

In the general formula shown in the above Chemical formula 31, A
For example, those having the structures shown in Table 9 below are conceivable, but are not particularly limited.

[0076]

[Table 9]

On the other hand, the long-chain hydrocarbon compound having an amino group in the molecule is represented by the general formula shown below. This long-chain hydrocarbon compound has 6 or more and 30 or less carbon atoms, and any compound selected regardless of a branched structure, an unsaturated bond, an isomer structure, or an alicyclic structure can be used. It is preferably a straight chain having 10 to 22 carbon atoms. When the carbon number is small, the effect is small, and when the carbon number is large, the solubility is small, so that it becomes uncommon. Of these, trialkylamines in which all hydrogens of amino groups are replaced with alkyl groups are preferable.

[0078]

[Chemical 32]

In the sixth invention of the present application, a lubricant prepared by adding a long-chain hydrocarbon having an amino group in the molecule to the perfluoropolyether derivative having a phosphoric acid group at the terminal is used. Here, the addition amount of the long-chain hydrocarbon having an amino group in the molecule is preferably 1% or more in terms of molar ratio. By setting the addition amount of the long-chain hydrocarbon having an amino group in the molecule within the above range, good results can be obtained without deteriorating the friction coefficient even under various usage conditions.

As a magnetic recording medium to which the present invention is applied, a so-called metal thin film type magnetic recording medium in which a magnetic film is formed as a magnetic layer on the surface of a non-magnetic support by a method such as vapor deposition is suitable. In this metal thin film type magnetic recording medium, an underlayer may be interposed between the non-magnetic support and the magnetic layer.

In this metal thin film type magnetic recording medium,
The non-magnetic support and the metal magnetic thin film are not particularly limited, and any conventionally known material can be used.

That is, as the non-magnetic support, the same one as the coating type magnetic recording medium can be used. Further, when a rigid substrate such as an Al alloy plate or a glass plate is used as the non-magnetic support, an oxide film such as an alumite treatment or a Ni-P film is formed on the surface of the substrate, and the surface is hard. It may be designed.

As the metal magnetic thin film, any of those formed as a continuous film by a PVD method such as plating, sputtering or vacuum deposition can be used. For example, metals such as Fe, Co and Ni and Co- Ni-based alloy, Co-
Pt-based alloy, Co-Pt-Ni-based alloy, Fe-Co-based alloy, Fe-Ni-based alloy, Fe-Co-Ni-based alloy, Fe
-Ni-B system alloy, Fe-Co-B system alloy, Fe-Co
Examples include in-plane magnetic recording metal magnetic films made of —Ni—B type alloys and Co—Cr type alloy thin films.

In particular, in the case of in-plane magnetization recording metal magnetic thin film,
Bi, Sb, Pb, Sn, Ga, on the non-magnetic support in advance
An underlayer of a low melting point non-magnetic material such as In, Ge, Si, and Tl is formed in advance, and a metal magnetic material is vapor-deposited or sputtered from the vertical direction to diffuse the low melting point non-magnetic material in the metal magnetic thin film. The orientation may be eliminated to secure the in-plane isotropic property, and the coercive force may be improved.

In the case of the hard disk as described above, a hard protective film such as a carbon film, a diamond-like or amorphous carbon film, a chromium oxide film and a SiO2 film may be formed on the surface of the metal magnetic thin film. Good.

Examples of the method of retaining the above-mentioned various lubricants in the metal thin film type magnetic recording medium include a method of top-coating a lubricant layer on the surface of the metal magnetic thin film or the surface of the protective film. In this case, the coating amount of each lubricant desirably is 0.5 to 100 mg / m ^2, more preferably in the range of 1 to 20 mg / m ^2.

These lubricants may be used alone as a lubricant for the magnetic recording medium, or may be used in combination with a conventionally known lubricant. Furthermore, in order to cope with more severe conditions and maintain the lubricating effect, the weight ratio is 30: 70-70:
An extreme pressure agent may be used in combination at a compounding ratio of about 30.

The extreme pressure agent reacts with the metal surface by the frictional heat accompanying the partial metal contact in the boundary lubrication region, and forms a reaction product film to prevent friction and wear. Which is a phosphorus-based extreme pressure agent,
Sulfur-based extreme pressure agent, halogen-based extreme pressure agent, organometallic extreme pressure agent,
Any compound type extreme pressure agent or the like can be used.

In addition to the above lubricant and extreme pressure agent, a rust preventive agent may be used in combination, if necessary. As the rust preventive, any rust preventive commonly used as a rust preventive for magnetic recording media of this type can be used, and examples thereof include phenols, naphthols, quinones, nitrogen atom-containing heterocyclic compounds, and oxygen atoms. And a heterocyclic compound containing a sulfur atom.

By the way, in the above-mentioned metal thin film type magnetic recording medium, a back coat layer, an undercoat layer and the like may be formed, if necessary, in addition to the metal magnetic thin film which is the magnetic layer. The back coat layer is formed by coating a resin binder similar to that used in the magnetic coating film with carbon-based fine powder for imparting conductivity and an inorganic pigment for controlling the surface roughness.

In the present invention, the above-mentioned various lubricants may be internally added to the back coat layer or may be contained by a top coat. Alternatively, the above lubricant is internally added to both the magnetic coating film, the metal magnetic thin film and the back coat layer,
Various combinations such as top coating are also possible.

[0092]

[Function] A lubricant obtained by adding a compound having a long-chain alkyl group to a compound having a skeleton of perfluoropolyether exhibits a good lubricating effect and reduces the friction coefficient. Further, the lubricating action is not impaired even under severe conditions such as high temperature and high humidity, low temperature and low humidity, and the characteristics thereof are not deteriorated.

Therefore, in the magnetic recording medium in which the lubricant is retained on the surface of the magnetic layer formed on the non-magnetic support, the running property is improved by the excellent lubricating effect of the lubricant, and the durability is improved. Is improved.

[0094]

EXAMPLES Hereinafter, specific examples of the present invention will be described, but it goes without saying that the present invention is not limited to these examples.

Example 1 In this example, as a lubricant, a perfluoropolyether having an oxyalkylene group having a hydroxyl group at the end was used.
HO (CH ₂ CH ₂ O) nCH ₂ CF ₂ O (CF ₂ CF ₂ O) p (CF ₂ O) q CF ₂ CH ₂ (OCH ₂ C
The durability and runnability of metal thin film magnetic recording media using H ₂ ) nOH to which a long-chain hydrocarbon compound having an amino group in the molecule was used were examined under various operating conditions.

First, using 10 kinds of lubricants 1 to 10,
A vapor deposition tape was produced according to the following procedure. The types of long-chain hydrocarbon compounds having an amino group in the molecule used when synthesizing the lubricants 1 to 10 are shown in Table 10 below.

[0097]

[Table 10]

That is, Co was deposited on the surface of a polyethylene terephthalate film having a thickness of 10 μm by the oblique evaporation method to form a ferromagnetic metal thin film having a thickness of 200 nm to form a magnetic layer.

Next, the above lubricants 1 to 10 were dissolved in a mixed solvent of freon and ethanol, and these were coated on the surface of the above metal magnetic thin film so that the coating amount was 5 mg / m ² , to form a lubricant layer. Formed. Then, the obtained magnetic tape was cut into a width of 8 mm to prepare sample tapes 1 to 10.

With respect to each of the sample tapes 1 to 10 thus obtained, the friction coefficient under each condition at a temperature of 25 ° C. and a humidity of 60%, a temperature of −5 ° C., and a temperature of 40 ° C. and a humidity of 80%, The still durability and the shuttle durability were measured respectively. The results are shown in Table 11 below.

For comparison, a blank tape having no lubricant layer formed of the above lubricant,
Perfluoropolyether HO (CH ₂ CH ₂ O) nCH ₂ C with oxyalkylene group whose terminal is hydroxyl group as lubricant
F ₂ O (CF ₂ CF ₂ O) p (CF ₂ O) qCF ₂ CH ₂ (OCH ₂ CH ₂ ) nOH was also measured in the same manner for the comparative tape, and the results are also shown in Table 11 below. I wrote it.

[0102]

[Table 11]

In Table 11, the still durability represents the decay time required for the output to decrease by 3 dB in the pause state. The shuttle durability represents the number of shuttles until the output drops by 3 dB when the shuttle runs for 2 minutes each time.

As is clear from the results shown in Table 11, as compared with the case where a perfluoropolyether having an oxyalkylene group having a hydroxyl group at the end was used alone as a lubricant used for a vapor deposition tape, When a lubricant comprising a long-chain hydrocarbon compound having an amino group in the molecule is added to a perfluoropolyether having an oxyalkylene group whose terminal is a hydroxyl group as in Examples, various types are used. Has a low friction coefficient even under
It has been found that very good results can be obtained without deterioration of still durability and shuttle durability.

Example 2 Next, the lubricant 2 used in the above Example 1 was used as a lubricant, and the lubricant 2 was incorporated into the molecule of the perfluoropolyether having an oxyalkylene group having a hydroxyl group at the terminal. Ten kinds of lubricants 11 to 20 were synthesized by changing the ratio of the added amount of the long-chain hydrocarbon compound having an amino group (stearylamine) as shown in Table 12 below.

[0106]

[Table 12]

Then, using the obtained lubricants 11 to 20, sample tapes 11 to 20 were prepared by the same method as in Example 1 except above. Then, with respect to each of the sample tapes 11 to 20, the friction coefficient under each condition at the temperature of 25 ° C. and the humidity of 60% and the temperature of the 40 ° C. and the humidity of 80% was measured in the same manner as in Example 1 above. The results are shown in Table 13 below.

[0108]

[Table 13]

From Table 13 above, the molar ratio of the long-chain hydrocarbon compound having an amino group in the molecule to the perfluoropolyether having an oxyalkylene group having a hydroxyl group at the end as in this Example was 0. It has been found that by using the lubricant added in the range of 0.01 to 100, very good results can be obtained without deteriorating the friction coefficient even under various use conditions.

Example 3 In this example, as a lubricant, a perfluoropolyether having an oxyalkylene group having a hydroxyl group at the end was used.
HO (CH ₂ CH ₂ O) nCH ₂ CF ₂ O (CF ₂ CF ₂ O) p (CF ₂ O) q CF ₂ CH ₂ (OCH ₂ C
A metal thin film magnetic recording medium using a mixture of H ₂ ) nOH and trialkylamine was examined for durability and runnability under various usage conditions.

First, a sample tape was prepared in the same manner as in Example 1 except that 10 kinds of lubricants 21 to 30 were used. The types of trialkylamine used for the lubricants 21 to 30 are shown in Table 14 below.

[0112]

[Table 14]

With respect to each of the sample tapes 21 to 30 thus obtained, the coefficient of friction under each condition at a temperature of 25 ° C. and a humidity of 60%, a temperature of −5 ° C., and a temperature of 40 ° C. and a humidity of 80%, The still durability and the shuttle durability were measured respectively. The results are shown in Table 15 below.

For comparison, a blank tape having no lubricant layer formed of the above lubricant,
Perfluoropolyether HO (CH ₂ CH ₂ O) nCH ₂ C with oxyalkylene group whose terminal is hydroxyl group as lubricant
F ₂ O (CF ₂ CF ₂ O) p (CF ₂ O) qCF ₂ CH ₂ (OCH ₂ CH ₂ ) nOH was also measured in the same manner for the comparative tape, and the results are also shown in Table 15 below. I wrote it.

[0115]

[Table 15]

In Table 15, the still durability represents the decay time required for the output to decrease by 3 dB in the pause state. The shuttle durability represents the number of shuttles until the output drops by 3 dB when the shuttle runs for 2 minutes each time.

As is clear from the results shown in Table 15, as compared with the case where a perfluoropolyether having an oxyalkylene group having a hydroxyl group at the end is used alone as a lubricant used in a vapor deposition tape, When a lubricant obtained by adding a trialkylamine to a perfluoropolyether having an oxyalkylene group whose terminal is a hydroxyl group as in the example is used, a low friction coefficient is obtained even under various use conditions. It was found that very good results were obtained without deterioration of still durability and shuttle durability.

Example 4 Next, the lubricant 22 used in the above Example 3 was used as a lubricant, and the trialkylamine for the perfluoropolyether having an oxyalkylene group having a hydroxyl group at the terminal in this lubricant 22. Ten kinds of lubricants 31 to 40 were synthesized by changing the ratio of the addition amount of (dimethylstearylamine) as shown in Table 16 below.

[0119]

[Table 16]

Subsequently, sample tapes 31 to 40 were prepared by using the obtained lubricants 31 to 40 and by the same method as in Example 1 except above. Then, with respect to each of the sample tapes 31 to 40, the friction coefficient under each condition at the temperature of 25 ° C. and the humidity of 60% and the temperature of the 40 ° C. and the humidity of 80% was measured in the same manner as in Example 1 above. The results are shown in Table 17 below.

[0121]

[Table 17]

From Table 17 above, trialkylamine was added in a molar ratio of 0.01 to 100 to the perfluoropolyether having an oxyalkylene group having a hydroxyl group at the end as in this Example. It has been found that by using the lubricant, very good results can be obtained without deteriorating the friction coefficient even under various usage conditions.

Example 5 In this example, a metal thin film type magnetic recording medium using a perfluoropolyether having a carboxyl group at the terminal and an amino acid ester as a lubricant was used under various conditions of use. We examined durability and runnability.

First, using 16 kinds of lubricants 41 to 56, a vapor deposition tape was produced according to the following procedure. In addition,
The type and molecular weight of perfluoropolyether having a carboxyl group at the terminal and the type of amino acid ester used when synthesizing the lubricants 41 to 56 are shown in Table 1 below.
8 and Table 19. The amount of each amino acid ester added is such that when a monofunctional perfluoropolyether having a carboxyl group at the terminal is used, the amino acid ester is added to the perfluoropolyether having a carboxyl group at the terminal. In the case of using a polyfunctional one in a molar amount, a double equivalent (that is, an equimolar amount to the carboxyl group of the perfluoropolyether having a carboxyl group at the terminal) was added.

[0125]

[Table 18]

[0126]

[Table 19]

That is, Co was deposited on the surface of a 14 μm thick polyethylene terephthalate film by the oblique evaporation method, and a ferromagnetic metal thin film having a film thickness of 200 nm was formed to form a magnetic layer.

Next, the lubricants 41 to 56 are dissolved in ethanol, and these are applied to the surface of the metal magnetic thin film at a coating amount of 5
A lubricant layer was formed by coating each so as to have a mg / m ² . Then, the obtained magnetic tape was cut into a width of 8 mm to prepare sample tapes 41 to 56.

With respect to each of the sample tapes 41 to 56 thus obtained, the friction coefficient, the still durability and the shuttle durability under each condition were measured in the same manner as in Example 1 above. The results are shown in Tables 20 and 21 below.
Shown in.

For comparison, a blank tape having no lubricant layer formed of the above lubricant,
Comparative tapes a to c in which perfluoropolyether having three kinds of carboxyl groups at the ends (lubricants a to c and their structures are also shown in the above Table 15) are used alone as a lubricant. Was also measured in the same manner, and the results are also shown in Table 21 below.

[0131]

[Table 20]

[0132]

[Table 21]

As is clear from the results of Tables 20 and 21, the lubricant used in the vapor-deposited tape of this example is more effective than the case where perfluoropolyether having a carboxyl group at the end is used alone. In the case of using a lubricant in which amino acid ester is added to perfluoropolyether having a carboxyl group at the terminal like this, a low friction coefficient is exhibited under various usage conditions, and still durability and shuttle durability are improved. It has been found that very good results can be obtained without deterioration.

Further, since the lubricant used in this example is soluble in ethanol, it is possible to eliminate the use of CFC as a diluent and it is also excellent in the global environment.

[0135]Example 6 Next, when synthesizing the lubricant, add a carboxyl group to the end.
Amino Acid Ester for Perfluoropolyether
Change the ratio of the amount of added
Then, various lubricants 57 to 84 were synthesized. The above
Perfluoropolyether with carboxyl group at the end
As a lubricant 57-70 in HOOCCF₂(OC₂F_Four) p
(OCF₂) qOCF₂COOH and F in lubricants 71-84
(CF₂CF₂CF ₂O) nCF₂CF₂Using COOH, amino acid ester
As C₁₇H₃₅COOCH₂CH₂N (CH₃)₂It was used.

[0136]

[Table 22]

[0137]

[Table 23]

Subsequently, sample tapes 57 to 84 were produced by using the obtained lubricants 57 to 84 and by the same method as in Example 5 except above. Then, for each of the sample tapes 57 to 84, in the same manner as in Example 1 above, when the temperature was 25 ° C., the humidity was 60%, the temperature was −5 ° C., the temperature was 40
The coefficient of friction under each condition was measured at a temperature of 80 ° C. and a humidity of 80%. The results are shown in Tables 24 to 26 below.

[0139]

[Table 24]

[0140]

[Table 25]

[0141]

[Table 26]

From Tables 24 to 26 above, as in this example, the molar ratio of the amino acid ester to the perfluoropolyether having a carboxyl group at the end was 0.1.
It was found that by using the lubricant added in the range of 01 to 100, very good results can be obtained without deterioration of the friction coefficient even under various use conditions.

Example 7 In this example, a long-chain carboxylic acid ester ROOC (CH ₂ CH ₂ O) nCH ₂ CF ₂ O of perfluoropolyether having an oxyalkylene group having a hydroxyl group at the terminal was used as a lubricant. (CF ₂ C
F ₂ O) p (CF ₂ O) qCF ₂ CH ₂ (OCH ₂ CH ₂ ) nCOOR with a long-chain hydrocarbon compound with an amino group in the molecule The durability and running property under various usage conditions were examined.

First, using 16 kinds of lubricants 85 to 100, the sample tape 8 was prepared in the same manner as in the first embodiment.
5-100 were produced. However, these lubricants 85 to 10
The solvent of No. 0 was changed to the mixed solvent of Freon and ethanol used in Example 1 above, and toluene was used here. The alkyl group R of the long-chain carboxylic acid ester of perfluoropolyether having an oxyalkylene group whose terminal is a hydroxyl group used in the synthesis of the above-mentioned lubricants 85 to 100 and the long group having an amino group in the molecule. The types of chain hydrocarbon compounds are as shown in Table 27 below.

[0145]

[Table 27]

For each of the sample tapes 85 to 100 thus obtained, the friction coefficient, the still durability and the shuttle durability were measured in the same manner as in Example 1 above. The results are shown in Tables 28 and 29 below.

For comparison, a blank tape having no lubricant layer formed of the above lubricant,
Perfluoropolyether HO (CH ₂ CH ₂ O) nCH ₂ C with oxyalkylene group whose terminal is hydroxyl group as lubricant
F ₂ O (CF ₂ CF ₂ O) p (CF ₂ O) qCF ₂ CH ₂ (OCH ₂ CH ₂ ) nOH was also measured in the same manner for a comparative tape, and the results are shown in Table 29 below. I wrote it.

[0148]

[Table 28]

[0149]

[Table 29]

As is clear from the results of Tables 28 and 29, the lubricant used in the vapor-deposited tape is better than the case where perfluoropolyether having an oxyalkylene group having a hydroxyl group at the end is used alone. Also, as in this example, a long-chain carboxylic acid ester of perfluoropolyether having an oxyalkylene group having a hydroxyl group at the terminal is added with a long-chain hydrocarbon compound having an amino group in the molecule for lubrication. It was found that when the agent was used, a low coefficient of friction was exhibited even under various conditions of use, and very good results were obtained without deterioration in still durability and shuttle durability.

Further, since the lubricant used in this example is soluble in toluene, it is possible to eliminate the use of CFC as a diluent, and it is excellent in the global environment.

Example 8 Next, when synthesizing a lubricant, a long-chain carbonization having an amino group in the molecule is obtained with respect to a long-chain carboxylic acid ester of perfluoropolyether having an oxyalkylene group whose terminal is a hydroxyl group. Ten kinds of lubricants 101 to 110 were synthesized by changing the ratio of the amount of hydrogen compound added as shown in Table 30 below. The long-chain carboxylic acid ester of perfluoropolyether having an oxyalkylene group whose terminal is a hydroxyl group is C ₁₇ H ₃₅ OOC (CH ₂ CH ₂ O) nCH ₂ CF ₂ O (C
F ₂ CF ₂ O) p (CF ₂ O) qCF ₂ CH ₂ (OCH ₂ CH ₂ ) nCOOC ₁₇ H ₃₅
Dimethylstearylamine C ₁₈ H ₃₇ N (CH ₃ ) ₂ was used as a long-chain hydrocarbon compound having an amino group in the molecule.

[0153]

[Table 30]

Then, using the obtained lubricants 101 to 110, sample tapes 101 to 110 were produced by the same method as in Example 7 except for the above. Then, for each of the sample tapes 101 to 110, when the temperature is 25 ° C. and the humidity is 60%, the temperature is 40 ° C. and the humidity is 8 as in the first embodiment.
The coefficient of friction under each condition at 0% was measured. The results are shown in Table 31 below.

[0155]

[Table 31]

From Table 31 above, for the long-chain carboxylic acid ester of perfluoropolyether having an oxyalkylene group having a hydroxyl group at the terminal as in this Example, the long-chain hydrocarbon having an amino group in the molecule was used. It has been found that by using a lubricant in which the compound is added in a molar ratio of 0.01 to 100, very good results can be obtained without deteriorating the friction coefficient even under various conditions of use.

Example 9 In this example, a long-chain carboxylic acid ester ROOC (CH ₂ CH ₂ O) nCH ₂ CF ₂ O of perfluoropolyether having an oxyalkylene group having a hydroxyl group at the terminal was used as a lubricant. (CF ₂ C
F ₂ O) p (CF ₂ O) qCF ₂ CH ₂ (OCH ₂ CH ₂ ) nCOOR with a trialkylamine added to it for durability of metal thin film magnetic recording media under various operating conditions , The running property was examined.

First, using 16 kinds of lubricants 111 to 126, sample tapes 111 to 126 were prepared in the same manner as in Example 1. However, these lubricants 111
The solvent of ~ 126 was changed to the mixed solvent of Freon and ethanol used in Example 1 above, and toluene was used here. The types of the alkyl group R and the trialkylamine of the long-chain carboxylic acid ester of perfluoropolyether having an oxyalkylene group whose terminal is a hydroxyl group used when synthesizing the lubricants 111 to 126 are as follows. It is as shown in Table 32.

[0159]

[Table 32]

With respect to each of the sample tapes 111 to 126 thus obtained, the friction coefficient, the still durability and the shuttle durability were measured in the same manner as in Example 1 above. The results are shown in Table 33 and Table 34 below.

For comparison, a blank tape having no lubricant layer formed of the lubricant as described above,
Perfluoropolyether HO (CH ₂ CH ₂ O) nCH ₂ C with oxyalkylene group whose terminal is hydroxyl group as lubricant
F ₂ O (CF ₂ CF ₂ O) p (CF ₂ O) qCF ₂ CH ₂ (OCH ₂ CH ₂ ) nOH was also measured in the same manner for the comparative tape, and the results are shown in Table 34 below. I wrote it.

[0162]

[Table 33]

[0163]

[Table 34]

As is clear from the results in Tables 33 and 34, the lubricant used in the vapor-deposited tape is better than the case where perfluoropolyether having an oxyalkylene group having a hydroxyl group at the end is used alone. Also, as in this example, a long-chain carboxylic acid ester of perfluoropolyether having an oxyalkylene group having a hydroxyl group at the terminal is added with a long-chain hydrocarbon compound having an amino group in the molecule for lubrication. It was found that when the agent was used, a low coefficient of friction was exhibited even under various conditions of use, and very good results were obtained without deterioration in still durability and shuttle durability.

Further, since the lubricant used in this example is soluble in toluene, it is possible to eliminate the use of CFC as a diluent, and it is also excellent in global environment.

Example 10 Next, when synthesizing a lubricant, the ratio of the amount of trialkylamine added to the long-chain carboxylic acid ester of perfluoropolyether having an oxyalkylene group having a hydroxyl group at the terminal was determined as follows. By changing as shown in Table 35, 10 kinds of lubricants 127 to 136 were synthesized. As the long-chain carboxylic acid ester of perfluoropolyether having an oxyalkylene group having a hydroxyl group at the terminal,
C ₁₇ H ₃₅ COO (CH ₂ CH ₂ O) nCH ₂ CF ₂ O (CF ₂ CF ₂ O) p (CF ₂ O) qCF ₂ CH
₂ (OCH ₂ CH ₂₎ Use the nOCOC ₁₇ H _35, as the long-chain hydrocarbon compound having an amino group in the molecule was used dimethylstearylamine _{C 1 8 H 37 N (CH} 3) 2.

[0167]

[Table 35]

Subsequently, using the obtained lubricants 127 to 136, sample tapes 127 to 136 were produced by the same method as in Example 9 except for the above. Then, for each of the sample tapes 127 to 136, when the temperature is 25 ° C. and the humidity is 60%, the temperature is 40 ° C. and the humidity is 8 as in the first embodiment.
The coefficient of friction under each condition at 0% was measured. The results are shown in Table 36 below.

[0169]

[Table 36]

From Table 36 above, it is found that the trialkylamine is added in a molar ratio of 0.01 to 0.01 with respect to the long-chain carboxylic acid ester of perfluoropolyether having an oxyalkylene group having a hydroxyl group at the terminal as in this Example. It has been found that by using the lubricant added in the range of 100, very good results can be obtained without deteriorating the friction coefficient even under various usage conditions.

Example 11 In this example, various kinds of metal thin film magnetic recording media were used as a lubricant, in which a long-chain alkyl ester of perfluoropolyether having a carboxyl group at the terminal was added with an amino acid ester. The durability and runnability under the conditions of use were examined.

First, using 16 kinds of lubricants 137 to 152, sample tapes 137 to 152 were prepared in the same manner as in Example 5 above. However, these lubricants 137
As the solvent for ~ 152, the ethanol used in Example 5 was replaced with toluene here. The types and molecular weights of long-chain alkyl esters of perfluoropolyether having a carboxyl group at the terminal used when synthesizing the lubricants 137 to 152, and the types of amino acid esters are shown in Tables 37 and 38 below. As shown. Here, in the following Table 37, R represents C ₁₈ H ₃₇ .

[0173]

[Table 37]

[0174]

[Table 38]

With respect to the sample tapes 137 to 152 thus obtained, the friction coefficient, the still durability and the shuttle durability were measured in the same manner as in Example 1 above. The results are shown in Tables 39 and 40 below.

For comparison, a blank tape having no lubricant layer formed of the above lubricant,
The comparative tapes a to c in which the perfluoropolyether having three kinds of carboxyl groups at the ends (these are also described in Table 38 as the lubricants a to c) are used alone as the lubricant are also used. The same measurement was performed, and the results are also shown in Table 40 below.

[0177]

[Table 39]

[0178]

[Table 40]

As is clear from the results of Table 39 and Table 40, the lubricant used in the vapor-deposited tape of this example is more effective than the case where perfluoropolyether having a carboxyl group at the end is used alone. When a lubricant consisting of a long-chain alkyl ester of perfluoropolyether with a carboxyl group at the terminal and an amino acid ester is used, it shows a low friction coefficient even under various conditions of use and still durability. It was also found that very good results were obtained without deterioration of shuttle durability.

Further, since the lubricant used in this example is soluble in toluene, it is possible to eliminate the use of CFC as a diluent, and it is also excellent in global environment.

[0181]Example 12 Next, when synthesizing the lubricant, add a carboxyl group to the end.
Long-chain alkyl ester of perfluoropolyether
The ratio of the amount of amino acid ester added to
Alternatively, various lubricants 153-1 are changed as shown in Table 42.
80 was synthesized. In addition, it has a carboxyl group at the end.
Long-chain alkyl ester of perfluoropolyether
Then, in the lubricant 153-166, C₁₈H₃₇OOCCF₂(O
C₂F_Four) p (OCF₂) qOCF₂COOC₁₈H₃₇And lubricants 167-1
In 80, F (CF₂CF₂CF₂O) nCF ₂CF₂COOC₁₈H₃₇use
C as an amino acid ester₁₇H₃₅COOCH₂CH₂N (CH₃)₂
It was used.

[0182]

[Table 41]

[0183]

[Table 42]

Then, using the obtained lubricants 153-180, sample tapes 153-180 were produced by the same method as in Example 11 except above. Then, with respect to each of the sample tapes 153 to 180, the friction coefficient under each condition at the temperature of 25 ° C. and the humidity of 60% and the temperature of the 40 ° C. and the humidity of 80% was measured in the same manner as in Example 1 above. The results are shown in Tables 43 to 45 below.

[0185]

[Table 43]

[0186]

[Table 44]

[0187]

[Table 45]

From Tables 43 to 45 above, the amino acid ester was added in a molar ratio of 0.01 to 100 to the long-chain alkyl ester of perfluoropolyether having a carboxyl group at the terminal as in this Example. It was found that by using the above lubricant, very good results can be obtained without deteriorating the friction coefficient even under various usage conditions.

Example 13 In this example, various kinds of metal thin film magnetic recording media were used as the lubricant, in which amino acid ester was added to long-chain alkyl ester of perfluoropolyether having a hydroxyl group at the terminal. The durability and running property under the use conditions were examined.

First, using 16 kinds of lubricants 181 to 196, sample tapes 181 to 196 were produced in the same manner as in Example 11 above. The lubricant 181
The types and molecular weights of long-chain alkyl esters of perfluoropolyether having a hydroxyl group at the terminal used in the synthesis of ˜196 are as shown in Tables 46 and 47 below. Here, Table 46 below
In the formula, R represents C ₁₈ H ₃₇ .

[0191]

[Table 46]

[0192]

[Table 47]

With respect to each of the sample tapes 181 to 196 thus obtained, the friction coefficient, the still durability and the shuttle durability were measured in the same manner as in Example 1 above. The results are shown in Tables 48 and 49 below.

For comparison, a blank tape having no lubricant layer formed of the above lubricant,
The same applies to the comparative tapes d to f in which the perfluoropolyether having three types of hydroxyl groups at the terminals (these are also described as lubricants d to f in the structure in Table 47) is used alone as the lubricant. The results are shown in Table 4 below.
9 is also described.

[0195]

[Table 48]

[0196]

[Table 49]

As is clear from the results of Table 49 and Table 50, the lubricant used in the vapor-deposited tape is different from that in the case of using only perfluoropolyether having a hydroxyl group at the end as in this example. In the case of using a lubricant in which an amino acid ester is added to a long-chain alkyl ester of perfluoropolyether having a hydroxyl group at the end,
It was found that even under various conditions of use, the friction coefficient was low, and very good results were obtained without deterioration in still durability and shuttle durability.

Further, since the lubricant used in this example is soluble in toluene, it is possible to eliminate the use of CFC as a diluent, and it is also excellent in global environment.

Example 14 Next, when synthesizing a lubricant, the ratio of the amount of the amino acid ester added to the long-chain alkyl ester of perfluoropolyether having a hydroxyl group at the end is shown in Tables 50 and 5 below.
1, and various lubricants 197 to 224 were synthesized. As the long-chain alkyl ester of perfluoropolyether having a hydroxyl group at the terminal, the lubricant 1
97 to 210, C ₁₇ H ₃₅ COOCH ₂ CF ₂ (OC ₂ F ₄ ) p (OCF ₂ ) q
OCF ₂ CH ₂ OCOC ₁₇ H ₃₅ , F (CF ₂ CF ₂ CF ₂ O) nCF ₂ CF ₂ CH ₂₀ COC ₁₇ H ₃₅ was used in the lubricants 211 to 224, and C ₁₇ H ₃₅ was used as the amino acid ester. COOCH ₂ CH ₂ N (CH ₃ ) ₂ was used.

[0200]

[Table 50]

[0201]

[Table 51]

Subsequently, using the obtained lubricants 197 to 224, sample tapes 197 to 224 were produced by the same method as in Example 13 except for the above. Then, with respect to each of the sample tapes 197 to 224, the friction coefficient under each condition at the temperature of 25 ° C. and the humidity of 60% and the temperature of the 40 ° C. and the humidity of 80% was measured in the same manner as in Example 1 above. The results are shown in Tables 52 to 54 below.

[0203]

[Table 52]

[0204]

[Table 53]

[0205]

[Table 54]

From Tables 52 to 54 above, amino acid ester was added in a molar ratio of 0.01 to 100 to the long-chain alkyl ester of perfluoropolyether having a hydroxyl group at the terminal as in this example. It has been found that by using the lubricant, very good results can be obtained without deteriorating the friction coefficient even under various usage conditions.

Example 15 In this example, various uses of a metal thin film type magnetic recording medium in which a long-chain alkylamine was added to a perfluoropolyether derivative having a phosphoric acid group at a terminal was used as a lubricant The durability and running property under the conditions were examined.

First, using 10 kinds of lubricants 225 to 234, sample tapes 225 to 234 were prepared in the same manner as in Example 1 above (however, a polyethylene terephthalate film having a thickness of 14 μm was used). .
The types of perfluoropolyether derivatives having a phosphoric acid group at the end, the molecular weight of the perfluoropolyether group, and the types of long-chain alkylamines used when synthesizing the lubricants 225 to 234 are shown in Table 55 below. As shown.

[0209]

[Table 55]

With respect to each of the sample tapes 225 to 234 thus obtained, the friction coefficient, the still durability and the shuttle durability were measured in the same manner as in Example 1 above. The results are shown in Table 57 below.

For comparison, a blank tape having no lubricant layer formed of the above lubricant,
The same applies to the comparative tapes g to k in which five kinds of perfluoropolyether derivatives having a phosphoric acid group at the end (lubricants g to k and their structures are shown in Table 56) are used alone as a lubricant. The results are shown in Table 5 below.
8 is described.

[0212]

[Table 56]

[0213]

[Table 57]

[0214]

[Table 58]

As is clear from the results of Tables 56 and 58, the present Example was used as compared with the case where the perfluoropolyether derivative having a phosphoric acid group at the terminal was used alone as the lubricant used in the vapor deposition tape. When a lubricant obtained by adding a long-chain alkylamine to a perfluoropolyether derivative having a phosphoric acid group at the terminal is used, a low friction coefficient is exhibited even under various conditions of use, and still durability and It has been found that very good results can be obtained without degrading the shuttle durability.

[0216]Example 16 Next, when synthesizing a lubricant,
Long-chain alkylamido for fluoropolyether derivatives
Change the ratio of the added amount of carbon as shown in Table 51 or Table 52 below.
Then, various lubricants 235 to 258 were synthesized. In addition,
Perfluoropolyether derivative having a phosphate group at the end
As the body, in the lubricants 236 to 246, the following Table 5 is used.
Compound A shown in 0 is added to lubricants 247 to 258.
Compound B is used as a long-chain alkylamine
Stearylamine C₁₈H₃₇NH ₂ It was used.

[0217]

[Table 59]

[0218]

[Table 60]

[0219]

[Table 61]

Subsequently, using the obtained lubricants 235 to 258, sample tapes 235 to 258 were produced in the same manner as in Example 15 except for the above. However, the solvent of these lubricants 235 to 258 was changed to the mixed solvent of Freon and ethanol used in Example 15, and Freon was used here. And each sample tape 2
35 to 258, in the same manner as in Example 1 above, when the temperature is 25 ° C., the humidity is 60%, the temperature is −5 ° C., the temperature is 40.
The coefficient of friction under each condition was measured at a temperature of 80 ° C. and a humidity of 80%. The results are shown in Tables 62 and 63 below.

For comparison, a blank tape having no lubricant layer formed of the above lubricant,
Comparative tapes 1 and 2 using the compounds A and B alone as lubricants and comparative tape 3 using stearylamine alone were measured in the same manner, and the results are shown in Table 64 below.

[0222]

[Table 62]

[0223]

[Table 63]

[0224]

[Table 64]

From Tables 62 to 64 above, use of a lubricant in which a long-chain alkylamine is added in a molar ratio of 1% or more to the perfluoropolyether derivative having a phosphoric acid group at the terminal as in this example. As a result, it was found that a very good result can be obtained without deteriorating the friction coefficient even under various usage conditions. Example 17 In this example, a metal thin film type magnetic recording medium using a perfluoropolyether derivative having a phosphoric acid group at the terminal and a trialkylamine as a lubricant was tested for durability under various use conditions. And running performance were examined.

First, using 10 kinds of lubricants 259 to 268, sample tapes 259 to 268 were prepared in the same manner as in Example 1 (however, a polyethylene terephthalate film having a thickness of 14 μm was used). .
The types of perfluoropolyether derivatives having a phosphoric acid group at the terminal, the molecular weights of the perfluoropolyether groups, and the types of long-chain alkylamines used when synthesizing the lubricants 259 to 268 are shown in Table 65 below. As shown.

[0227]

[Table 65]

With respect to each of the sample tapes 259 to 268 thus obtained, the friction coefficient, the still durability and the shuttle durability were measured in the same manner as in Example 1 above. The results are shown in Table 67 below.

For comparison, a blank tape having no lubricant layer formed of the above lubricant,
The same applies to the comparative tapes g to k in which five kinds of perfluoropolyether derivatives having a phosphoric acid group at the end (lubricants g to k and their structures are shown in Table 66) are used alone as a lubricant. The results are shown in Table 6 below.
8 is described.

[0230]

[Table 66]

[0231]

[Table 67]

[0232]

[Table 68]

As is clear from the results of Tables 67 and 68, the present Example was used as compared with the case where the perfluoropolyether derivative having a phosphoric acid group at the terminal was used alone as the lubricant used for the vapor deposition tape. When a lubricant prepared by adding a trialkylamine to a perfluoropolyether derivative having a phosphoric acid group at the terminal is used, it shows a low friction coefficient even under various conditions of use, still durability and shuttle It has been found that very good results can be obtained without deterioration of durability.

Example 18 Next, when synthesizing a lubricant, the ratio of the amount of trialkylamine added to the perfluoropolyether derivative having a phosphoric acid group at the terminal was changed as shown in Table 51 or Table 52 below. Various lubricants 269-292 were synthesized. In addition,
As the above-mentioned perfluoropolyether derivative having a phosphoric acid group, the lubricants 269 to 280 are listed in Table 5 below.
0 was used as the compound A, the lubricants 281-292 were used as the compound B, and the trialkylamines were all dimethylstearylamine C ₁₈ H ₃₇ N (CH ₃ ) ₂ .

[0235]

[Table 69]

[0236]

[Table 70]

[0237]

[Table 71]

Subsequently, sample tapes 269 to 292 were prepared by using the obtained lubricants 269 to 292 and using the same method as in Example 17 except for the above. However, the solvent of these lubricants 269 to 292 was changed to the mixed solvent of Freon and ethanol used in Example 17, and Freon was used here. And each sample tape 2
For 69 to 292, the temperature is 25 ° C., the humidity is 60%, the temperature is −5 ° C., and the temperature is 40 as in the first embodiment.
The coefficient of friction under each condition was measured at a temperature of 80 ° C. and a humidity of 80%. The results are shown in Tables 72 and 73 below.

For comparison, a blank tape having no lubricant layer formed of the lubricant as described above,
Comparative tapes 1 and 2 using the compounds A and B alone as lubricants and comparative tape 3 using dimethylstearylamine alone were also measured in the same manner, and the results are shown in Table 74 below.

[0240]

[Table 72]

[0241]

[Table 73]

[0242]

[Table 74]

From Tables 72 to 74 above, it is possible to use a lubricant in which a trialkylamine is added in a molar ratio of 1% or more to a perfluoropolyether derivative having a phosphoric acid group at the terminal as in this example. It has been found that even under various conditions of use, very good results can be obtained without the friction coefficient deteriorating.

[0244]

As is apparent from the above description, in the magnetic recording medium of the present invention, a lubricant obtained by adding a compound having a long chain alkyl group to a compound having a skeleton of perfluoropolyether is formed on the surface of the magnetic layer. Since it possesses it, it can maintain good lubricity under any conditions of use and maintain its properties for a long period of time. Therefore, in the magnetic recording medium of the present invention, excellent running properties, wear resistance, and durability can be ensured, and reliability can be improved.

Claims (15)

[Claims] 1. A magnetic recording medium comprising at least a magnetic layer on a non-magnetic support, wherein a perfluoropolyether having an oxyalkylene group having a hydroxyl group at the end is formed on the surface of the magnetic layer. A magnetic recording medium comprising a lubricant containing a long-chain hydrocarbon compound having an amino group in the molecule represented by Chemical formula 1. [Chemical 1] 2. The long-chain hydrocarbon compound having an amino group in the molecule is a trialkylamine in which all the hydrogens of the amino group are substituted with alkyl groups.
The magnetic recording medium described. 3. The magnetic recording medium according to claim 1, wherein the amount of the long-chain hydrocarbon compound having an amino group in the molecule added is in the range of 0.01 to 100 in terms of molar ratio. . 4. A magnetic recording medium comprising at least a magnetic layer on a non-magnetic support, the perfluoropolyether having a carboxyl group at the terminal represented by the following chemical formula 2 or chemical formula 3 on the surface of the magnetic layer. A magnetic recording medium containing a lubricant containing an amino acid ester represented by Chemical Formula 4 or Chemical Formula 5 below. [Chemical 2] [Chemical 3] [Chemical 4] [Chemical 5] 5. The magnetic recording medium according to claim 4, wherein the amount of the amino acid ester added is in the range of 0.01 to 100 in molar ratio with respect to the carboxyl groups of the perfluoropolyether. 6. A magnetic recording medium comprising at least a magnetic layer on a non-magnetic support, wherein the surface of the magnetic layer is a long chain of perfluoropolyether having an oxyalkylene group having a hydroxyl group at the end. A magnetic recording medium comprising a carboxylic acid ester and a lubricant obtained by adding a long-chain hydrocarbon compound having an amino group in the molecule represented by the following chemical formula 6. [Chemical 6] 7. The long-chain hydrocarbon compound having an amino group in the molecule is a trialkylamine in which all the hydrogens of the amino group are substituted with an alkyl group.
The magnetic recording medium described. 8. The magnetic recording medium according to claim 6, wherein the amount of the long-chain hydrocarbon compound having an amino group in the molecule added is in the range of 0.01 to 100 in terms of molar ratio. . 9. A magnetic recording medium comprising at least a magnetic layer on a non-magnetic support, the perfluoropolyether having a carboxyl group at the terminal represented by the following chemical formula 7 or 8 on the surface of the magnetic layer. A magnetic recording medium comprising a long-chain alkyl ester of 1), and a lubricant obtained by adding an amino acid ester represented by the following chemical formula 9 or chemical formula 10 below. [Chemical 7] [Chemical 8] [Chemical 9] [Chemical 10] 10. The magnetic recording medium according to claim 9, wherein the added amount of the amino acid ester is in the range of 0.01 to 100 in terms of molar ratio. 11. A magnetic recording medium comprising at least a magnetic layer on a non-magnetic support, comprising a perfluoropolyether having a hydroxyl group at the terminal represented by the following chemical formula 11 or 12 on the surface of the magnetic layer. A magnetic recording medium comprising a long-chain alkyl ester and a lubricant obtained by adding an amino acid ester represented by the following Chemical formula 13 or Chemical formula 14 below. [Chemical 11] [Chemical 12] [Chemical 13] [Chemical 14] 12. The magnetic recording medium according to claim 11, wherein the added amount of the amino acid ester is in the range of 0.01 to 100 in terms of molar ratio. 13. A magnetic recording medium comprising at least a magnetic layer on a non-magnetic support, wherein the surface of the magnetic layer is a perfluoropolyether derivative having a phosphoric acid group at the terminal represented by the following chemical formula 15. A magnetic recording medium having a lubricant containing a long-chain hydrocarbon compound having an amino group in the molecule represented by the following chemical formula 16. [Chemical 15] [Chemical 16] 14. The magnetic recording medium according to claim 13, wherein the long-chain hydrocarbon compound having an amino group in the molecule is a trialkylamine in which all the hydrogens of the amino group are substituted with alkyl groups. 15. The magnetic recording medium according to claim 13, wherein the amount of the long-chain hydrocarbon having an amino group in the molecule added is 1% or more in a molar ratio.