JPH05342565A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To provide a magnetic recording medium excellent in durability and running property in any environment as a magnetic recording medium applied to the field of information industry, etc., by coating a magnetic recording medium having a carbon layer on the magnetic recording layer with an alkylsilane compd. at a controlled temp. CONSTITUTION:A carbon layer 3 formed by plasma CVD is coated with an alkylsilane compd. having satisfactory adhesion to the carbon layer 3 and excellent in lubricity at a low temp. The objective magnetic recording medium having still characteristics and blurring resistance independently of a change in environmental temp. or humidity and capable of ensuring excellent running property can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetic recording medium applied to the information industry field.

[0002]

2. Description of the Related Art A magnetic recording medium is currently being developed by a direct plating method, a sputtering method, a vacuum deposition method, an ion plating method or the like on a non-magnetic substrate for the purpose of realizing a high density recording medium. ing. When recording and reproducing a signal, the magnetic recording medium is liable to be rubbed or abraded due to direct contact between a member constituting a traveling system such as a head and a cylinder and the surface of the magnetic recording medium, and abrasion powder or damage is generated during traveling.

Therefore, in order to obtain the recording / reproducing characteristics smoothly, an example of treating the surface of the recording medium with a lubricant is disclosed in US Pat.
842939, US Pat. No. 4,871,625, US Pat. No. 4,876,113, US Pat.
No. 0689, U.S. Pat. No. 4,912,252,
US Pat. No. 4,920,919, US Pat. No. 4,910,68, US Pat. No. 4,810,43 for shape control processing.
No. 5, U.S. Pat. No. 4,806,417, and for abrasion resistance, the abrasion resistance is as described in U.S. Pat. No. 4,960,609 and U.S. Pat. No. 4,889,767.
It has been proposed to improve wear resistance.

[0004]

However, although these methods certainly improve running performance and damage to some extent, as the number of times of deck running increases, the lubricating layer may peel off or the surface of the protective layer may be damaged. As a result, the running characteristics became unstable, and stable evaluation of recording and reproduction could not be continued.

The present invention is intended to solve the above problems,
The objective is to realize a magnetic recording medium with excellent runnability and durability.

[0006]

In order to solve the above-mentioned problems, the present invention provides a magnetic recording medium having a magnetic recording layer on a non-magnetic substrate, in which carbon is formed by plasma CVD and then the drying temperature is further applied to the carbon. Is coated at low temperature with a solution containing a long-chain alkylsilane compound.

[0007]

[Function] By controlling the drying temperature at a low temperature, the formation of the friction polymer of the long-chain alkylsilane compound, which is oriented near the surface of the magnetic medium, is promoted, and the improvement of the coating ratio improves the reduction of friction. A magnetic recording medium with improved reduction of the force required for its characteristics is realized.

[0008]

1 is a sectional view of a magnetic recording medium according to an embodiment of the present invention. In FIG. 1, 1 is a non-magnetic substrate, 2 is a magnetic recording layer, 3 is a carbon layer formed by plasma CVD, and 4
Is a lubrication layer containing a long-chain alkylsilane compound.

As the non-magnetic substrate 1 which can be used in the magnetic recording medium of the present invention, polyamide, polyimide, polysulfone, polycarbonate, polypropylene, polyethylene, polyethylene terephthalate, polyethylene naphthalate, cellulose acetate, polyvinyl chloride and the like can be used. There are films and plates made of well-known materials such as polymer materials, non-magnetic metal materials, glass, and ceramic materials such as porcelain.

As the magnetic material for forming the magnetic recording layer 2, at least one metal selected from Fe, Co and Ni, or Mn, Cr, Ti, P, Y,
There are Sm, Bi and the like or alloys in which these oxides are combined, and in particular, the magnetic recording layer composed of at least two elements selected from Co, Cr and Ni has high magnetic anisotropy, It has excellent corrosion resistance. These can be formed by a method such as a vacuum vapor deposition method, a sputtering method, an ion plating method, a plating method. It is needless to say that the magnetic recording layer 2 described below may be any element as long as it is a constituent that facilitates magnetization, and is not limited to the above composition.

The carbon layer 3 formed by plasma CVD described in the present invention forms a carbon layer on the surface of the magnetic medium under plasma conditions by introducing a lower hydrocarbon such as methane or ethane in a gaseous state. At this time, the carbon layer is formed in various states depending on the process conditions, but the amorphous state is preferable as the film structure such as scratch resistance and treatment of the lubricating layer. Needless to say, the method for producing carbon may be a sputtering method, a solution dipping method, or the like and may be applied to the present invention. Although this thickness depends on the members of the running deck, it is preferably 50 to 100 Å in consideration of wear resistance and spacing loss.

The lubrication layer 4 is a long-chain hydrocarbon chain having a hydrocarbon chain having 16 to 24 carbon atoms or a fluorine-containing hydrocarbon group having 1 to 8 carbon atoms, and the end portion thereof is a hydroxyl group having a strong binding force. It is composed of a branched long-chain alkylsilane compound having a group, an alkoxyl group such as halogen, methoxy, ethoxy, and propoxy. For example, r- (N-octadecylsuccinylamino) propyltriethoxysilane,
r- (N-heptadecylsuccinylamino) propyltriethoxysilane, r- (N-eicosylsuccinylamino) propyltriethoxysilane, r- (N, N-dioctadecylsuccinylamino) propyltriethoxysilane, r- { N- (tris (heptadecyloxymethyl)) methylsuccinylamino} propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluorodecylamide-propyltriethoxysilane, 1H, 1H-perfluorodecylamide-propyltriethoxysilane There are compounds such as silane and perfluorodecylamido-propyltriethoxysilane, and these can be used alone or as a mixture, and these are preferable in terms of handling, availability, cost and ease of film formation.

When these are applied and dried, the film structure of the lubrication layer 4 is affected by temperature, and as a result, this naturally reflects on the characteristics such as abrasion. This is because, in the above compound, the alkoxy group undergoes polycondensation depending on the heating state, so that the form of Si—O—Si formation differs depending on the degree of reaction. Therefore, by controlling the temperature, it is possible to realize a magnetic recording medium excellent in running property and durability. Only in this way it is possible to prevent solid-to-solid contact with the head / tape surface and to show improved wear resistance to repeated repetitions such as still properties.

As described above, the magnetic recording layer 2 and the carbon layer 3 are formed on the non-magnetic substrate 1, and the long-chain alkylsilane compound is applied onto the carbon layer 3 while the temperature is kept low. The magnetic recording medium has excellent running properties and durability.

Examples will be described in detail below. (Example 1) On a non-magnetic substrate 1 having a thickness of 10 μm using a polyimide film (width 200 mm) having a thickness of 9.0 μm,
Under the conditions shown in (Table 1), the first layer is a Co-Cr (element ratio 80: 20%, AES analysis 1000Å) layer, and the second layer is a Co oxide layer (AES analysis 1000Å layer) formed by continuous vacuum deposition. A magnetic recording layer 2 is formed by forming a film having a thickness of 2000Å.

[0016]

[Table 1]

Further, under the conditions shown in (Table 2), an alternating frequency of 20 KHz, an alternating voltage of 700 V, a direct voltage of 800 V, a direct current of 300 mA, under the conditions shown in (Table 2),
A carbon layer 3 having a thickness of 140Å is produced by plasma CVD at a tape speed of 3 to 4 m / min. At this time, argon gas is flowing in at the same time. Also in the other Examples described below, the magnetic recording layer and the carbon layer are all manufactured by this method.

[0018]

[Table 2]

Further thereafter, a solution of r- (N, N-dioctadecylsuccinylamino) propyltriethoxysilane dissolved in isopropylate alcohol at 800 ppm was used at a tape speed of 5 to 10 m / min (Table 3).
Samples were prepared by coating at the drying temperature shown in (Nos. 1 to 4). At the same time, add stearic acid 1500
It was prepared by coating with a ppm solution (Sample No.
5).

[0020]

[Table 3]

Next, these are cut into a width of 8 mm and evaluated as a cassette tape (magnetic recording medium) with a length of 20 minutes.

The evaluation method is performed in an 8 mm deck running system, and changes in cylinder load (40 mm aluminum) and pulsating state and shape of envelope are observed on an oscilloscope. The magnetic head mounted at this time has a track width Tw of 7.5 μ.
m, gap length G1 = 0.15 μm, coil 20 turns LAM type head. At the same time, the still characteristics are 23 ° C., RH is less than 10%, Tw = 20 μm,
The measurement is performed using a magnetic head having a gap length G1 of 0.2 μm and a coil of 20 turns.

Then, the sample No. In Nos. 1 to 3, the cylinder load was 40 to 42 mV and the running property was secured, and even when the head was observed, almost no uneven wear was observed, the reproduction voltage was not lowered, and the envelope shape was clear. And even if this state is repeated 50 times, there is almost no change.
On the other hand, sample No. In No. 4, although the initial runnability was equivalent, the cylinder load increased from 50 mV to 100 mV with the number of times of repetition. Similarly, sample No. No. 5 is not good even for running once or twice, and a drop in the reproduction voltage and a partial drop in the signal are observed, and powder etc. is generated on the tape surface and the run naturally stops.

On the other hand, in the still characteristics, the sample No. 1,
Sample No. 5 was slightly insufficient for 10 to 20 minutes under the condition of the additional load of 20 gf. 5 is 60 minutes. For these, sample No. No. 2 and No. 3 have no signal drop for 60 minutes, and are the same under the conditions under normal environment. This is considered to be the result of the temperature reflecting the wearability (durability).

Therefore, plasma C is formed on the magnetic recording medium.
It can be said that the magnetic recording medium prepared by forming the VD carbon layer 3 and controlling the temperature at a low temperature to apply the long-chain alkylsilane has excellent running properties and durability.

On the non-magnetic substrate 1 having a thickness of 9 μm using the polyimide film of (Example 2), Co—Cr was magnetized in a composition range of 20 to 30 wt% (element ratio of Cr / Co, confirmed by atomic absorption method). Form the layers. Then, in this state, a CoO layer having a thickness of 800 Å is further formed in the vapor deposition machine while introducing oxygen to form a recording layer having a total thickness of 2000 Å.

Further, after the thickness of the 100 Å carbon layer was produced according to the same production method as in Example 1, the drying temperature step was further changed as shown in (Table 4) (Sample Nos. 6 to 10). The same deck running test as in 1 was performed, and this was repeated up to 100 times to compare the characteristics. At this time, r- (N, heptadecylsuccinylamino) propyltriethoxysilane was used as the material, and the solution concentration was 9
It is adjusted to 00 ppm and the tape speed is kept constant at 10 m / min.

As shown in (Table 4), the sample No. manufactured at high temperature was used. No. 6 had a slightly high cylinder load probably because the friction property was slightly lowered, and a little dust-like deposit was observed on the head surface after repeating 100 times. It is considered that this is because the polymerization proceeded too much.

[0029]

[Table 4]

On the other hand, sample N in which the drying temperature is not controlled at all
o. In No. 10, although the running smoothness functions, the head surface has an adhered substance that does not immediately become a clean surface even if it is cleaned after the test with the paper in which ethanol is permeated. It is considered that this is laminated in the monomer state as it is.

On the other hand, the sample No. prepared by controlling the drying temperature at 30 to 60 ° C. In Nos. 7 and 8, the cylinder load was as small as 40 to 45 mV, and the head surface was clean after 100 times without any change. In addition, the sample No. with a slightly high temperature was used. In No. 9, the head surface is clean, but in the runnability, Sample No. Somewhat inferior to 7,8. This means that the formation state of the alkylsilane lubricating layer is optimized by controlling the temperature.

Therefore, it is understood that when the magnetic recording medium is manufactured by controlling the drying temperature of 30 to 60 ° C., the number of times of repeating the magnetic recording medium is improved and a medium having no transfer material to the head surface is obtained.

[0033]

As is apparent from the above description, the magnetic recording medium of the present invention has Co, C on one surface of the non-magnetic substrate.
It has a thin film magnetic recording layer of a mixture of r and Ni or a metal oxide containing them, and a carbon layer for plasma CVD is formed on the thin film magnetic recording layer. Since it is produced by coating a silane compound, it has excellent running properties and durability and can be used at any temperature.

[Brief description of drawings]

FIG. 1 is a sectional view of a magnetic recording medium according to an embodiment of the present invention.

[Explanation of symbols]

 1 non-magnetic substrate 2 magnetic recording layer 3 carbon layer 4 lubrication layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yu Odagiri 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. A non-magnetic substrate, a magnetic recording layer formed on the non-magnetic substrate and containing Co, Cr, and Ni, a carbon layer formed on the magnetic recording layer, and a carbon layer formed on the carbon layer. A magnetic recording medium having a lubrication layer containing an alkylsilane compound. 2. The alkylsilane compound has 16 to 16 carbon atoms.
A long hydrocarbon chain having 24 hydrocarbon chains or a fluorine-containing hydrocarbon group having 1 to 8 carbon atoms, the other being halogen,
2. The magnetic recording medium according to claim 1, containing at least one compound containing an alkoxy group, a carboalkoxy group, a carboxy group, a hydroxy group, and a phenoxy group. 3. The alkylsilane compound is r- (N, N-
The magnetic recording medium according to claim 1 or 2, which is dioctadecylsuccinylamino) propyltriethoxysilane. 4. In a magnetic recording medium having a magnetic recording layer on a non-magnetic substrate, a carbon protective layer is formed by plasma CVD, and then a long-chain alkylsilane compound is applied thereon by controlling the drying temperature at a low temperature. A method of manufacturing a magnetic recording medium, which is characterized in that it is manufactured. 5. The method for producing a magnetic recording medium according to claim 2, wherein the coating and drying temperature is controlled to be 30 to 60 ° C.