JPH05279681A - Lubricant and magnetic recording medium coated therewith - Google Patents

Abstract

PURPOSE:To obtain a lubricant with sustained excellent lubricity useful for e.g. magnetic recording materials, good in travelability, wear resistance and durability by incorporating an alkoxycarbonyl group-terminated perfluoropolyether with an amino group-contg. long chain hydrocarbon. CONSTITUTION:The objective lubricant can be obtained by incorporating (A) an alkoxycarbonyl group-terminated perfluoropolyether with (B) a long chain hydrocarbon having amino group in the molecule (e.g. stearylamine) at the molar ratio B/A of 0.01 to 100. This lubricant maintains excellent lubricity under various service conditions along with sustaining lubricating effect for a long time, giving magnetic recording media excellent in travelability, wear resistance and durability, etc., by its application on the magnetic layer surface of a magnetic recording media bearing such a magnetic layer at least on a nonmagnetic substrate.

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 a perfluoropolyether having an alkoxycarbonyl group at its terminal and a long-chain hydrocarbon having an amino group in the molecule. The present invention relates to a magnetic recording medium coated with a lubricant added with. Further, the present invention relates to a magnetic recording medium coated with a lubricant in which a long-chain hydrocarbon having an amino group in the molecule is added in a molar ratio of 0.01 to 100 to a perfluoropolyether having an alkoxycarbonyl group at the terminal. .

[0002]

2. Description of the Related Art For example, in a so-called metal thin film type magnetic recording medium in which a ferromagnetic metal material is deposited on a non-magnetic support by a technique such as vapor deposition and the magnetic layer is used as a magnetic layer, the surface of the magnetic layer is not smooth. Since it is extremely good, the substantial contact area with sliding members such as magnetic heads and guide rollers is large,
Therefore, there are many problems such that the friction coefficient becomes large and the adhesion phenomenon (so-called sticking) is likely to occur and running performance and durability are lacking.

Therefore, use of various kinds of lubricants has been studied in order to improve these problems, and friction has been hitherto caused by top-coating a higher fatty acid or ester thereof on the magnetic layer of the magnetic recording medium. Attempts have been made to reduce the coefficient. By the way, the lubricant used for the magnetic recording medium is required to have extremely strict characteristics, and it is difficult to cope with the conventional lubricant.

That is, 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) a lubricant with a magnetic head. Since pacing becomes a problem, it is necessary to apply an extremely thin coating, to exhibit sufficient lubrication characteristics even in that case, and (3) to endure long-term use or long-term use and maintain the lubrication effect. To be done.

However, conventionally used higher fatty acids and esters thereof are frozen and solidified under low temperature conditions such as 0 ° C. or lower, impairing the function as a lubricant, and long-term durability. Tend to lack.

[0006]

As described above, in the field of magnetic recording media, practical characteristics such as running durability are left unsatisfactory due to the lack of ability of the lubricant used. Therefore, the present invention provides a magnetic recording medium that maintains excellent lubricity under various conditions of use, has a long-lasting lubrication effect, and has excellent runnability, wear resistance, durability, and the like. It is intended.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies as a means of achieving the above-mentioned object, and as a result, have found that perfluoropolyether having an alkoxycarbonyl group at the terminal has a long chain having an amino group in the molecule. The present invention has been completed by finding that a magnetic recording medium coated with a lubricant containing a hydrocarbon is suitable for this purpose.

That is, the magnetic recording medium of the present invention is a magnetic recording medium in which at least a magnetic layer is formed on a non-magnetic support, and a perfluoropolyether having an alkoxycarbonyl group at the terminal is amino-aminoated in the molecule. The magnetic recording medium is characterized by having a lubricant containing a long-chain hydrocarbon having a group. The addition amount of the long-chain hydrocarbon having an amino group in the molecule is 0.0 to a perfluoropolyether having an alkoxycarbonyl group at the terminal in a molar ratio.
The inventors have found that a magnetic recording medium coated with a lubricant added in an amount of 1 to 100 is suitable for this purpose, and completed the present invention.

That is, the magnetic recording medium of the present invention is a magnetic recording medium in which at least a magnetic layer is formed on a non-magnetic support, and is intramolecular with respect to a perfluoropolyether having an alkoxycarbonyl group at the terminal. The magnetic recording medium is characterized by containing a lubricant containing a long-chain hydrocarbon having an amino group in a molar ratio of 0.01 to 100.

That is, according to the present invention, particularly by applying to the surface of a thin film magnetic recording medium such as a vapor deposition tape, good durability can be obtained even when used under severe conditions such as high temperature and high humidity or low temperature and low humidity. Moreover, the characteristics are not deteriorated.

The long-chain hydrocarbon having an amino group in the molecule of the present invention specifically has the structure shown in Table 1, but has a carbon number of 6 or more and 30 or less, a branched structure, an unsaturated bond, It can be selected regardless of the isomer structure or the alicyclic structure. More preferably, the number of carbon atoms is 10 or more, and 22 or less is linear. 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. As the perfluoropolyether having an alkoxycarbonyl group at the terminal, it is possible to use monofunctional and polyfunctional perfluoropolyethers. For example, as the monofunctional,

Demnum manufactured by Daikin Industries, Ltd.

[Chemical 1]

Craytox manufactured by DuPont

[Chemical 2]

Made by Montefluos

[Chemical 3]

As polyfunctionality, Fomblin Z-DEAL manufactured by Montefluos Co.

[Chemical 4] However, the present invention is not limited to this.

Here, k, l, m, n, p and q in the chemical structural formula of the perfluoropolyether represent integers of 1 or more. The molecular weight is not particularly limited, but is preferably about 600 to 5,000. If the molecular weight is too high, the effect of the adsorbing group will be small, and if it is small, the effect of fluorine will be weak.

The magnetic recording medium of the present invention comprises, as a lubricant, a compound obtained by adding a long-chain hydrocarbon having an amino group in the molecule to perfluoropolyether having an alkoxycarbonyl group at the terminal.

The magnetic recording medium to which the present invention is applied is 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. It is possible. Further, this metal thin film type magnetic recording medium can be applied to a magnetic recording medium having a structure in which an underlayer is interposed between a non-magnetic support and a magnetic layer.

In this case, the non-magnetic support and the metal magnetic thin film of the applicable metal thin film type magnetic recording medium are not particularly limited, and any conventionally known one can be used. For example, as the non-magnetic support, the same one as the above-mentioned coating type magnetic recording medium can be used. In this case, 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 substrate surface to harden the surface. You may do so.

The metal magnetic thin film is formed as a continuous film by a PVD method such as plating, sputtering or vacuum deposition, and is made of a metal such as Fe, Co or Ni, or Co-Ni.
Alloys, Co-Pt alloys, Co-Pt-Ni alloys,
Fe-Co based alloy, Fe-Ni based alloy, Fe-Co-N
Examples include in-plane magnetization recording metal magnetic films and Co-Cr alloy thin films made of i-based alloys, Fe-Ni-B-based alloys, Fe-Co-B-based alloys, Fe-Co-Ni-B-based alloys, and the like. ..

In particular, in the case of an 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, Tl is formed in advance, a magnetic metal material is vapor-deposited or sputtered from the vertical direction, and the low-melting point non-magnetic material is diffused in the metal magnetic thin film. The orientation may be eliminated to secure the in-plane isotropic property, and the anti-magnetism 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 SiO ₂ film is formed on the surface of the metal magnetic thin film. Good.

As a method of retaining a lubricant prepared by adding a long-chain hydrocarbon having an amino group in the molecule to the perfluoropolyether having an alkoxycarbonyl group at the terminal, a metal thin film type magnetic recording medium A method of top-coating a lubricant layer on the surface of the magnetic thin film or the surface of the protective film can be mentioned. In this case, as the coating amount of the compound obtained by adding a long-chain hydrocarbon having an amino group in the molecule to perfluoropolyether having an alkoxycarbonyl group at the terminal,
0.5-100 mg / m ² is desirable, and 1-
It is more preferably 20 mg / m ² .

The above-mentioned compound obtained by adding a long-chain hydrocarbon having an amino group in the molecule to the perfluoropolyether having an alkoxycarbonyl group at the terminal may be used alone as a lubricant for a magnetic recording medium. It may be used in combination with a known lubricant.

Further, an extreme pressure agent may be used in combination in a weight ratio of about 30:70 to 70:30 in order to cope with more severe conditions and maintain the lubricating effect. The extreme pressure agent reacts with the metal surface by frictional heat generated when a metal contact is partially generated in the boundary lubrication region, and forms a reaction product film to prevent friction and wear. Any of phosphorus-based extreme pressure agents, sulfur-based extreme pressure agents, halogen-based extreme pressure agents, organic metal-based extreme pressure agents, complex-based extreme pressure agents and the like can be used.

In addition to the above-mentioned 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, heterocyclic compounds containing a nitrogen atom, 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. For example, the back coat layer is formed by coating a resin binder similar to that of the magnetic coating film with a carbon-based fine powder for imparting conductivity and an inorganic pigment for controlling the surface roughness.

In the present invention, a lubricant obtained by adding a long-chain hydrocarbon having an amino group in the molecule to the above-mentioned perfluoropolyether having an alkoxycarbonyl group at the terminal is internally added to this back coat layer, or a top coat. You may make it contain by. Alternatively, magnetic coating, metal magnetic thin film and back coat layer are all internally added as a lubricant by adding a long chain hydrocarbon having an amino group in the molecule to perfluoropolyether having an alkoxycarbonyl group at the end, top coat Various combinations are also possible.

[0029]

[Function] A lubricant prepared by adding a long-chain hydrocarbon having an amino group in the molecule to a perfluoropolyether having an alkoxycarbonyl group at the end, especially as a perfluoropolyether having an alkoxycarbonyl group in the molecule as the addition amount. On the other hand, a lubricant in which a long-chain hydrocarbon having an amino group in the molecule is added in a molar ratio of 0.01 to 100 exerts a good lubricating action to reduce the friction coefficient. Further, this lubricating action is not impaired even under severe conditions such as low temperature. Therefore, a magnetic recording medium prepared by applying a lubricant containing a long-chain hydrocarbon having an amino group in a molecule to a perfluoropolyether having an alkoxycarbonyl group in the molecule is a perfluoropolyether having an alkoxycarbonyl group in the molecule. The lubrication effect of the lubricant obtained by adding a long-chain hydrocarbon having an amino group to a polyether improves the running property and improves the durability.

[0030]

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. Table 1 shows a lubricant obtained by adding a long-chain hydrocarbon having an amino group in the molecule to perfluoropolyether having an alkoxycarbonyl group in the molecule.

[0031]

[Table 1]

Using the compounds shown in Table 1, magnetic recording media shown below were prepared. An example applied to a metal thin film type magnetic recording medium (vapor deposition tape) will be described. -Example 1-Co was deposited on a polyethylene terephthalate film having a thickness of 10 µm by an oblique vapor deposition method to form a ferromagnetic metal thin film having a thickness of 200 nm. Next, on the surface of this metal magnetic thin film, the lubricant 1 (synthetic compound 1) in Table 1 dissolved in a mixed solvent of freon and ethanol was applied at a coating amount of 5 mg / m ²
And was cut into 8 mm width to prepare a sample tape.

-Examples 2 to 14-The same method as in Example 1 except that the lubricant 1 in Table 1 used as the lubricant in Example 1 was replaced with lubricant 2-lubricant 14. A sample tape was prepared from

As comparative examples, a blank tape containing no lubricant and a case where perfluoropolyether having an alkoxyl carbonyl group at its end was used alone as a lubricant were also measured.

Regarding each sample tape produced as described above, that is, Examples 1 to 14 and Comparative Example 1
-Regarding Comparative Example 4, the friction coefficient, the still durability, and the shuttle durability were measured at a temperature of 25 ° C and a humidity of 60%, a temperature of 40 ° C and a humidity of 80%, and a temperature of -5 ° C. For the still durability, the decay time of the output in the pause state up to -3 dB was evaluated. The shuttle durability was evaluated by performing shuttle travel for 2 minutes each time and counting the number of shuttles until the output decreased by 3 dB. The results are shown in Tables 2 and 3.

[0036]

[Table 2]

[0037]

[Table 3]

-Examples 15 to 34-Next, the results are shown when the addition amount is changed.
Tables 4 and 5 show the compositions of lubricants in which a long-chain hydrocarbon having an amino group in the molecule is added in a molar ratio of 0.01 to 100 to a perfluoropolyether having an alkoxycarbonyl group at the terminal.

[0039]

[Table 4]

[0040]

[Table 5]

Using the lubricants shown in Tables 4 and 5, the following magnetic recording medium was prepared in the same manner as in Example 1. Lubricant 1 in Table 1 used as a lubricant in Example 1
In place of Lubricant 15-Lubricant 34 in Tables 4 and 5,
Otherwise, a sample tape was produced by the same method as in Example 1. With respect to each of the sample tapes manufactured as described above, the coefficient of friction was measured at a temperature of 25 ° C. and a humidity of 60% and at a temperature of 40 ° C. and a humidity of 80%. In addition,
As a comparative example, a blank tape containing no lubricant and a case where perfluoropolyether having an alkoxycarbonyl group at the end was used alone as a lubricant were also measured. The results are shown in Tables 6 and 7.

[0042]

[Table 6]

[0043]

[Table 7]

As is clear from Table 2, Table 3, Table 6 and Table 7, a perfluoropolyether having an alkoxycarbonyl group at the end is used as compared with the case where a perfluoropolyether having an alkoxycarbonyl group at the terminal is used alone as a lubricant. By using it as a lubricant in which a long-chain hydrocarbon having an amino group in the molecule is added to fluoropolyether, the friction coefficient, still durability, shuttle durability, etc. are very good without deterioration under various conditions. Results were obtained. Further, as the addition amount at that time, a long-chain hydrocarbon having an amino group in the molecule is added in a molar ratio of 0.01 to 100 to a perfluoropolyether having an alkoxycarbonyl group at a terminal and used as a lubricant. As a result, the friction coefficient did not deteriorate under various conditions, and very good results were obtained.

[0045]

As is apparent from the above description, the magnetic recording medium of the present invention is a lubricant obtained by adding a long-chain hydrocarbon having an amino group in the molecule to perfluoropolyether having an alkoxycarbonyl group at the terminal. Since it has the above properties, it is possible to maintain the lubricity under any use condition, and to maintain the lubricity for a long period of time. Therefore,
The magnetic recording medium of the present invention has excellent running properties, abrasion resistance and durability.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C10N 40:18

Claims (3)

[Claims] 1. A lubricant obtained by adding a long-chain hydrocarbon having an amino group in the molecule to a perfluoropolyether having an alkoxycarbonyl group at the terminal. 2. A magnetic recording medium comprising at least a magnetic layer on a non-magnetic support, wherein a perfluoropolyether having an alkoxycarbonyl group at the end of the magnetic layer has a long-chain carbonization having an amino group in the molecule. A magnetic recording medium coated with a lubricant containing a hydrogen compound. 3. In a lubricant obtained by adding a long-chain hydrocarbon having an amino group in the molecule to a perfluoropolyether having an alkoxycarbonyl group at the terminal, the molar ratio of the long-chain hydrocarbon to the perfluoropolyether is 0.1. 01 to 1
A lubricant that is 00.