JPH05217152A - Lubricative film for magnetic recording medium - Google Patents

Abstract

PURPOSE:To maintain the lubricative efficiency of the title film by a method wherein a lubricating-oil layer is formed on a lubricating-oil fixation layer. CONSTITUTION:The film of a lubricating-oil fixing agent 1 is formed on the surface of a medium Ru by a coating method, a vapor deposition method, a sputtering method or the like. Then, the film of a lubricating oil 2 is formed additionally on the fixing- agent layer 1 by a coating method, a vapor deposition method, a sputtering method or the like. Lastly, the surface of the medium is cleaned by using a solvent which does not dissolve the fixing agent, and the surface is dried. The fixing agent 1 is a large ring aromatic compound such as phthalocyanine, porphyrin or the like, and the film is formed in such a way that a molecular plane comes into contact with the surface of the medium. When the film of the lubricating oil is formed on the film, a Lewis base which exists in the functional group of the lubricating oil is bonded to a Lewis acid in the functional group of the fixing agent 1, and the lubricating-oil molecule 2 is fixed to the fixing agent 1. In this manner, the surface of the medium is covered completely with the lubricating-oil fixing agent 1, and the lubricating oil is fixed to the fixing agent. Thereby, even under severe usage conditions, the lubricating oil is not stripped from the medium, and the lubricative effect of the title film can be maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating coating for magnetic recording media.

[0002]

2. Description of the Related Art In recent years, in magnetic recording devices, the head flying height over the medium has been reduced in order to increase the recording capacity. Along with this, so-called head crashes frequently occur, in which the head and the medium collide and are damaged. This head crash overlaps with various mechanical factors such as abnormal vibration of slider gimbal system, waviness of medium, adhesion of dust on medium, etc.
Further, it is considered to occur when the lubricating effect of the lubricant is reduced. The reason why the lubrication effect decreases is that the lubricant itself deteriorates mainly due to chemical changes and the lubricant peels off from the medium surface. Peeling is a more important issue. The present invention has been made in response to such conventional circumstances, without peeling from the medium surface,
An object of the present invention is to provide a lubricating coating for a magnetic recording medium that maintains a lubricating effect.

[0003]

DISCLOSURE OF THE INVENTION The present invention comprises a lubricating oil fixing layer made of a lubricating oil fixing agent, and a lubricating oil layer formed on the lubricating oil fixing layer. It is a film. Here, the lubricant fixing agent is preferably composed of a phthalocyanine compound or a porphyrin compound having a functional group containing a Lewis acid, and the lubricant is a functional group containing a Lewis base chemically bonded to the lubricant fixing agent. It is preferable that the fluorinated alkyl compound has a group.

[0004]

The magnetic recording medium lubricant according to the present invention is composed of two kinds of components. The first component is a lubricant fixing agent, which is, for example, a phthalocyanine-based or porphyrin-based compound having a functional group containing a Lewis acid in its molecule. The Lewis acids include iron (III) and ruthenium (II
Transition metal ions such as I) and osmium (III) are preferable, but not limited to this example. The second component is a lubricating oil, which is, for example, a fluorinated alkyl-based compound having in its molecule a functional group containing a Lewis base that forms a chemical bond with the functional group of the lubricant fixing agent. The Lewis base is preferably an amino group, a carboxyl group or an oxime group, but is not limited to this example. The phthalocyanine compound and the porphyrin compound used here as the lubricant fixing agent generally have high physical and chemical stability, and the thin film thereof has the property of firmly adhering to the medium surface. Alkyl fluoride used as a lubricating oil generally has high lubricating performance.

In the method of forming a lubricating coating for a magnetic recording medium composed of these two kinds of components, first, a lubricant fixing agent is formed on the surface of the medium. The film forming method can be performed by a coating method, a vapor deposition method, a sputtering method, or the like. Next, a lubricating oil is formed on the lubricating oil fixing agent layer to form a film. The film forming method can be performed by a coating method, a vapor deposition method, a sputtering method, or the like, but when using the coating method, a solvent that does not dissolve the lower layer must be used. Finally, the lubricating oil is dissolved, the medium surface is washed with a solvent that does not dissolve the lubricating oil fixing agent, and dried. The mechanism by which this magnetic recording lubricating coating is formed on the surface of the medium and exhibits a lubricating function is as follows. The lubricant fixing agent is a macrocyclic aromatic compound such as phthalocyanine or porphyrin, and is formed into a film with its molecular plane in contact with the medium surface. When a lubricating oil is formed on this film, the Lewis base present in the functional group of the lubricating oil binds to the Lewis acid present in the functional group in the lubricating oil fixative, and therefore the lubricating oil molecule is fixed to the lubricating fixative. It Finally, the unfixed lubricating oil molecules are washed away with a solvent that dissolves only the lubricating oil. In the lubricating coating for magnetic media thus provided on the medium, the surface of the medium is completely covered with the lubricant fixing agent, and the lubricant is fixed to the lubricant fixing agent.

[0006]

Embodiments of the present invention will now be described with reference to the drawings. Example 1 Ruthenium Phthalocyanine-Eicosafluoroundeca
Noic Acid Lubricating Film FIG. 2 is a molecular structure diagram of ruthenium phthalocyanine (a) and eicosafluoroundecanoic acid (b) used as a lubricant fixing agent and lubricant in this example. Further, FIG. 1 is an explanatory view showing a state when the lubricating oil molecule 2 is bonded to the lubricating oil fixative molecule 1. The film formation of the lubricant fixing agent on the 5-inch magnetic recording medium was performed by a spin coating method using a chloroform solution of ruthenium phthalocyanine (concentration: 0.1%). Medium rotation speed is 3000r
pm, and the film thickness after drying was 30 Å.
Then, a lubricating oil was formed on the thin film of the lubricating oil fixing agent.
The film formation method was performed by a spin coating method using an ethanol solution (concentration 0.1%) of eicosafluoroundecanoic acid. The medium rotation speed was 3000 rpm.
After keeping this medium at 60 ° C. for 3 hours, the whole medium was washed with ethanol. The contact start and stop (CSS) test was repeated 10,000 times for the magnetic recording medium manufactured in this way, and the friction coefficient before and after the test was measured. Met.

[0007]

As described above, according to the present invention, the lubricating oil does not separate from the medium even under severe use conditions, and the desired lubricating effect is maintained.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a state in which a lubricating oil molecule is bonded to a lubricating oil fixing agent molecule in one example of the present invention.

FIG. 2 is a diagram showing a molecular structure of an example of a lubricant fixing agent and a lubricant of the present invention.

[Explanation of symbols]

 1 Lubricating oil fixative molecule 2 Lubricating oil molecule

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Claims (3)

[Claims] 1. A lubricating oil fixing layer comprising a lubricating oil fixing agent,
A lubricating coating for a magnetic recording medium, comprising a lubricating oil layer formed on the lubricating oil fixed layer. 2. The lubricating coating for a magnetic recording medium according to claim 1, wherein the lubricant fixing agent comprises a phthalocyanine compound or a porphyrin compound having a functional group containing a Lewis acid. 3. The lubricating coating for a magnetic recording medium according to claim 1, wherein the lubricating oil comprises a fluorinated alkyl compound having a functional group containing a Lewis base that is chemically bonded to the lubricant fixing agent.