JPH07220249A - Cleaning solution for magnetic head - Google Patents

Abstract

PURPOSE:To obtain a cleaning soln. applied to a magnetic head, preventing the seizing of the head, improving the wear resistance and durability of the head and maintaining the effect over a long time. CONSTITUTION:An amine salt compd. of perfluoropolyether having a carboxyl group at a terminal and represented by the formula Rf-COO<->NH<+>R1R2R3 or R1R2R3N<+>HO<->CO-Rf-COO<->NH<+>R1R2R3 or a lubricant prepd. by adding an amine to the compd. in excess is dissolved in an org. solvent, to obtain the objective cleaning soln. for a magnetic head. In the formulae, Rf is perfluoropolyether, each of R1-R3 is H or hydrocarbon and at least, one of them is long chain hydrocarbon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricant solution used as a cleaner for a magnetic head used for a coating type magnetic tape or magnetic disk, and perfluoro having a carboxyl group at a terminal as a lubricant. A cleaning solution for a magnetic head, wherein a lubricant containing an amine salt of polyether or an amine added to the compound in excess is dissolved in an alcohol solvent as a thinner.

[0002]

2. Description of the Related Art In response to the recent demand for high recording density, a magnetic coating material containing very fine magnetic particles and a resin binder is coated on a non-magnetic support and applied. A so-called coating type magnetic recording medium as a magnetic layer or a thin film magnetic recording medium in which a magnetic layer is formed on a PET substrate by a vacuum deposition method, a plating method or a sputtering method has been developed.

Since the spacing loss is reduced and the density is increased, the smoothness of the surface of the magnetic layer becomes extremely good. As a result, the substantial contact area with the magnetic head becomes large, and the image sticking phenomenon (brown stain) easily occurs, leading to a level drop and problems such as durability. Therefore, in order to solve these problems, a lubricant is internally added, but this is not enough, and it may be top-coated on the magnetic layer.

However, even after the top coating, the surface lubricant concentration is reduced by diffusion into the magnetic layer. Especially, there is a problem that the lubricant is exhausted after aging. Therefore, organic matter such as binder or lubricant in the magnetic layer adheres to the head part, and it is oxidized and changes to something that cannot be wiped off with ordinary solvents. Leads to down.

As a solution to this problem, deck solvent is commercially available. The solvent is obtained by dissolving a perfluoro polyether perfluorocarbon _{(C n F 2n + 2)} , it is intended to remove soiling of the magnetic head. Further, as the effect of the lubricant, it is said that since perfluoropolyether has a polar group, it is adsorbed to a metal, and thus it is less likely to become dirty. However, since perfluoropolyether is used as a lubricant, perfluorocarbon must be used as a solvent, which makes the price very high. Although it dissolves in CFC Freon, it cannot be used from the viewpoint of the global environment.

[0006] Therefore, the development of a lubricant which does not use perfluorocarbon and has a very strong bond with a metal has been reached.

As described above, in the field of magnetic recording, the deterioration of durability due to the brown stain poses a problem and leaves the practical characteristics unsatisfactory.

Therefore, in the present invention, a long-chain amine salt compound of perfluoropolyether having a carboxyl group at the terminal has a perfluoropolyether in the molecular structure, but a general solvent other than CFC Freon, for example, ethanol. , Is also soluble in alcoholic solvents such as isopropanol, and is superior to commercially available perfluoropolyethers in its adsorptivity to metals.

Therefore, the present invention relates to a lubricant solution applied to a magnetic head which prevents seizure of the magnetic head and improves its wear resistance, durability and the like, and which is maintained for a long time.

[0010]

The present inventor has conducted extensive studies as a means of achieving the above-mentioned object, and as a result, added an amine salt compound of perfluoropolyether having a carboxyl group at the terminal to a magnetic head. The present invention has been completed by finding a magnetic head suitable for this purpose by applying an alcohol solution, for example.

That is, the present invention relates to a lubricant solution which is applied to a magnetic head before being used in advance. For example, an amine salt compound of perfluoropolyether having a carboxyl group at a terminal represented by the general formula 2 is used. It is a lubricant solution dissolved in an alcohol solvent.

[0012]

## STR2 ## ^{_{R f -COO - HN + R 1}} R 2 R 3 , or ^{_{R 1 R 2 R 3 N +}} H0 - CO-R f -COO - HN + R
₁ R ₂ R ₃ (R _f represents a perfluoropolyether group. R ₁ R ₂
R ₃ represents hydrogen or hydrocarbon, at least one of which represents a long-chain hydrocarbon having 10 or more carbon atoms. )

The amine salt compound of perfluoropolyether having a carboxyl group at the terminal of the present invention is easily synthesized according to the following method.

That is, the perfluoropolyether having a carboxyl group at the terminal and the amine can be easily obtained by uniformly dissolving them with stirring, and may be heated if necessary.

In the structural formula of amine, R ₁ R ₂ R ₃ represents hydrogen or hydrocarbon, and at least one of them represents a long chain hydrocarbon having 10 or more carbon atoms. At least one carbon number of the alkyl chain is preferably 10 or more, and if it is less than that, lubrication or solubility may be impaired. The hydrocarbon chain may be branched or may contain a double bond. Further, the molecular chain may contain an aromatic ring.

The structure (R _f ) of the main chain of the perfluoropolyether having a carboxyl group at the terminal of the present invention is shown in Structural Formula 3 and Structural Formula 4, but the present invention is not limited thereto.

The main chain of the monofunctional perfluoropolyether is represented by the following structural formula 3.

[0018]

Embedded image F (CF ₂ CF ₂ CF ₂ O) _n CF ₃ (OCF (CF ₃ ) CF ₂ ) _m (OCF ₂ ) _l F (CF (CF ₃ ) CF ₂ O) _k, etc.,

The polyfunctional perfluoropolyether is represented by the following structural formula (4).

[0020]

Embedded image There are (OC ₂ F ₄ ) _p (OCF ₂ ) _{q and the} like, but it goes without saying that the structure is not limited to this.

Here, l, m, n, k, p and q in the chemical structural formula of the perfluoropolyether are integers of 1 or more. The molecular weight is not particularly limited, but 60
About 0 to 5000 is preferable. When the molecular weight is too high, the effect of the terminal group becomes small, and when it is too small, the effect of the perfluoropolyether group becomes weak.

The magnetic recording medium of the present invention is a lubricant solution in which the amine salt compound of perfluoropolyether having a carboxyl group at the terminal is dissolved.

There has been a report in the past of applying the amine salt compound of perfluoropolyether having a carboxyl group at the terminal to a magnetic recording medium such as a vapor deposition tape (for example, JP-A-5-19497), but it was applied to a magnetic head. There is no example of improving durability.

The magnetic head is cleaned with this solution by some means, but it does not depend on the cleaning method. For example, it can be applied with a cotton swab or the like, or by a dipping method. The solvent used is not limited as long as it can be dissolved. For example, it can be dissolved in an alcohol solvent such as ethanol, methanol and isopropanol, and a ketone solvent such as methyl ethyl ketone depending on the kind of amine.
At that time, a boiling point of 50 ° C. or higher is convenient when considering maintenance.

Regarding the film thickness when applied to the head, if it is too thick, spacing is not preferable, and if it is too thin, durability is poor. 3-100
Angstrom is preferable, and 5 to 50 angstrom is preferable.

The magnetic head to which the present invention is applied may be a general ferrite head, MIG head, laminated head, inductive or MR thin film head, but is not particularly limited.

[0027]

[Function] A lubricant solution containing a perfluoropolyether amine salt compound having a carboxyl group at the terminal exerts a good lubricating effect by being applied to the head, and not only the durability of the magnetic head but also the magnetic recording medium. Improve the durability of. That is, the level reduction in magnetic recording is reduced. Further, this lubricating action is not impaired even under severe conditions such as low temperature. Therefore, by applying a lubricant solution containing a perfluoropolyether amine salt compound having a carboxyl group at this end, the running property of the magnetic recording medium is improved, and the durability of the magnetic recording system itself is improved.

[0028]

EXAMPLE One example of the magnetic head cleaning solution of the present invention will be described below with reference to FIG. Needless to say, the present invention is not limited to this embodiment.

As the magnetic recording medium, a coating type magnetic recording medium was prepared by using the following materials, and an example was carried out using it. Metal powder Magnetic powder 100 parts by weight Vinyl chloride-vinyl acetate copolymer 10.5 parts by weight Polyurethane resin 10.5 parts by weight Carbon (antistatic agent) 5 parts by weight Methyl ethyl ketone 150 parts by weight Toluene 150 parts by weight Cyclohexanone 100 parts by weight Butyl stearate 2 parts by weight of ester The above composition was used as a basic composition, mixed in a ball mill for 24 hours, taken out through a filter, 4 parts by weight of a curing agent was further added, and the mixture was stirred for 30 minutes. This magnetic coating material was applied onto a polyethylene terephthalate base having a thickness of 8 μm so that the thickness after drying would be 3 μm, magnetic field orientation was performed, and then dried and wound. After calendaring this 1
A sample tape was produced by cutting into a width of ½ inch.

This is an example of the coating type medium, but the magnetic recording medium is not limited to the coating type, and the invention can be sufficiently applied to a thin film magnetic recording medium. Similarly, as for the magnetic head, a TSS type head is used,
It goes without saying that the magnetic head is not limited to this type. It does not depend on the coating method.

Example 1 A 1% solution of lubricant 1 in Table 1 (dissolved in ethanol) was applied to a magnetic head before use with a cotton swab, and the tape was run.

[0032]

[Table 1]

Examples 2 to 14 In Example 1, instead of the solution of lubricant 1, the solutions of lubricants 2 to 14 shown in Table 1 were applied to the magnetic head. Others are the same as in the first embodiment.

Comparative Example Instead of the solution of Lubricant 1 in Example 1, a lubricant solution in which perfluoropolyether having a carboxyl group at the terminal was dissolved in perfluorohexane (Comparative Example 1),
Alternatively, a lubricant solution (comparative example 2) in which perfluoropolyether having an alkoxycarboxyl group at the terminal was dissolved in perfluorooctane was applied in the same manner as in Example 1 to make a comparative example. In addition, Comparative Example 3 uses a magnetic head not coated with the lubricant solution.

Table 2 shows the measurement results of the increase in the error rate due to the level down in the above Examples 1 to 14 and Comparative Examples 1 to 3. In addition, the observation results of the brown stain of the magnetic head at that time are also shown.

[0036]

[Table 2]

The error rate was measured and the brown stain was observed at 25 ° C., 60% RH, and 40 ° C., 80%.
It was performed under two conditions of RH.

The error rate is preferably 1 × 10 ^-3 or less. In Examples 1 to 14, satisfactory results were obtained in all cases. On the other hand, in Comparative Examples 1 to 3, satisfactory results were not obtained in all cases.

Brown stain is an optical microscope (300
X) was visually observed. The symbols shown in Table 2 will be described. The circle indicates that the sendust portion of the head is not dirty, the triangle indicates that it is slightly soiled, and the cross indicates that more than half of the dust has changed. Here, the state of O is desirable. In Examples 1 to 14, satisfactory results were obtained in all cases. In Comparative Examples 1 to 3, satisfactory results were not obtained.

Here, FIG. 1 shows a magnetic head in a state where no brown stain is generated (level ◯). The surface of the magnetic head is clean and clean. On the other hand, in the state where the brown stain is generated (X level), as shown in FIG. 2, many stains are attached to the surface of the magnetic head.

Example 15 to Example 20 In Example 1 or Example 4, the solvent shown in Table 3 was used instead of ethanol as the thinner. The other points are the same as in the first embodiment.

[0042]

[Table 3]

Also in Examples 15 to 20, the error rate was measured and the brown stain was observed.
The results are shown in Table 4. Satisfactory results were obtained in all cases.

[0044]

[Table 4]

Examples 21 to 29 In Example 1, the lubricant was dissolved in ethanol using the composition shown in Table 5. Others are the same as in the first embodiment.

[0046]

[Table 5]

The numerical values in Table 5 represent the molar ratio. Examples 21 to
Also in Example 29, the error rate was measured and the brown stain was observed. The results are shown in Table 6. Satisfactory results were obtained in all cases.

[0048]

[Table 6]

As is clear from the results of Tables 2, 4 and 6, brown stain was eliminated by applying a lubricant solution containing a perfluoropolyether amine salt compound having a carboxyl group at the terminal to the magnetic head. Alternatively, the magnetic recording system can be lowered to have a low error rate. Further, the durability at this time does not depend on the solvent, and the lubricant may contain an excess of amine.

From the above, according to this example, by applying a lubricant solution in which a perfluoropolyether amine salt compound having a carboxyl group at the terminal having very excellent lubricity is dissolved to a magnetic head, The lubricity can be maintained even under use conditions, and the lubricity can be maintained for a long period of time. Moreover, the effect does not depend on the thinner that dissolves. Therefore, by applying the lubricant solution of the present invention, the running property, wear resistance and durability can be improved.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0052]

As described above, according to the present invention,
By applying a lubricant solution in which a perfluoropolyether amine salt compound having a carboxyl group at the terminal having extremely excellent lubricity is applied to the magnetic head, the lubricity can be maintained under any use condition, and The lubricity can be maintained for a long period of time.

The effect does not depend on the thinner that dissolves. Therefore, by applying the lubricant solution of the present invention, the running property, wear resistance and durability can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example in which a cleaning solution for a magnetic head of the present invention is used.

FIG. 2 is an explanatory diagram showing an example of a conventional magnetic head.

[Explanation of symbols]

 1 Ferrite 2 Sendust 3 Magnetic Gap 4 Glass

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area // C10N 40:18

Claims (1)

[Claims] 1. A perfluoropolyether amine salt compound having a carboxyl group at the terminal represented by the general formula 1, or a lubricant obtained by adding an excess of amine to the compound is dissolved in an organic solvent. A cleaning solution for a magnetic head, characterized in that ## STR1 ## ^{_{R f -COO - HN + R 1}} R 2 R 3 , or ^{_{R 1 R 2 R 3 N +}} H0 - CO-R f -COO - HN + R
₁ R ₂ R ₃ (R _f represents a perfluoropolyether group. R ₁ R ₂
R ₃ represents hydrogen or hydrocarbon, at least one of which represents a long chain hydrocarbon. )