JPS61273727A - Magnetic recoding medium - Google Patents

Abstract

PURPOSE:To improve the traveling stability of the titled medium by providing a layer consisting of titanium nitride on a side opposite to the magnetic recording layer. CONSTITUTION:A layer consisting of titanium nitride is provided opposite to a magnetic recording layer. A magnetic recording medium is formed with the magnetic recording layer 1, a nonmagnetic substrate 2 and the rear lubricating layer 3. The magnetic recording layer 1 can be of a coating type obtained by dispersing magnetic particles, etc., in an org. binder and coating the material or of a thin film type formed by a thin film deposition method such as vapor deposition, sputtering and ion plating. Polyimide, polyamide, etc., can be used as the material of the nonmagnetic substrate 2. the rear lubricating layer 3 is a thin film consisting of titanium nitride and RiN can be exemplified as the titanium nitride. consequently, a magnetic recording medium having excellent traveling stability and which is hardly creased in winding in the production process can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a magnetic recording medium, and particularly to a magnetic recording medium with excellent running stability and antistatic properties.

[Prior Art] When recording and reproducing using a magnetic head and a magnetic recording medium, the head and the medium slide at a constant relative speed.Usually, the head is fixed or attached to a rotating drum. ing. The media moves at a constant speed relative to this fixed head or rotating drum.

It is important to stabilize this head-medium relative velocity. That is, when the relative speed becomes unstable, it causes frequency fluctuations and phase shifts, which lowers the S/N ratio. Furthermore, the contact state between the head and the medium becomes unstable, making it impossible to obtain stable reproduction output.

One of the reasons why the relative velocity between the head and the medium becomes unstable is the frictional resistance acting on the medium.

In other words, this friction causes the moving speed of the medium to fluctuate, and when the medium is something like a VTR tape, the tension on the tape increases due to friction, which increases the load on the rotating drum. Relative speed becomes unstable due to variations in rotational speed.

Conventionally, as a method for reducing this friction, a back lubricating layer has been provided by a coating method.

[Problems to be Solved by the Invention] In the conventional method, the back lubricating layer uses an organic binder, so there is a problem that the procedure for manufacturing the medium is limited depending on the method of forming the magnetic recording layer. was there.

That is, when a recording layer is formed by a vacuum evaporation method, a sputtering method, or the like, volatile components in the organic binder are released as gas in a vacuum chamber, and the degree of vacuum decreases. This situation becomes even worse when the film is formed while heating the substrate.

This often deteriorates the magnetic properties of the magnetic recording layer. Therefore, the magnetic recording layer must be formed before the back lubricating layer, but this is done without transporting the substrate film in a vacuum chamber. In this case, the film becomes difficult to stretch due to the formation of the recording layer, and the film is difficult to transport due to the large stretch, making it more likely to wrinkle during winding.

Furthermore, if the medium is charged, it not only deteriorates running but also causes noise, so it is desirable that the backside lubricant layer has conductivity and plays a role in preventing charging.
Carbon black or the like was mixed into the backside lubricating layer to impart conductivity, but the effect was insufficient when the substrate was highly charged.

Furthermore, another factor of running stability is the stiffness (bending rigidity) of the medium. If this is too small, not only the running becomes unstable, but also the contact situation between the head and the medium becomes unstable. For this reason, the thickness of the medium has conventionally been approximately 101L11 at its thinnest, but as VTR tapes and the like become longer, even thinner media are required.

The present invention was made to solve the above problems, and as a result, it is possible to obtain a magnetic recording medium with excellent running stability and antistatic performance, and at the same time, it is possible to reduce the thickness of the medium compared to the conventional one. It's now possible.

It also makes it easier to resolve problems such as wrinkles during the manufacturing process.

[Means and effects for solving the problems] According to the present invention, there is provided a magnetic recording medium having a magnetic recording layer on one side of a non-magnetic substrate, the side opposite to the magnetic recording layer being made of titanium nitride. A magnetic recording medium having a layer is provided.

FIG. 1 is a sectional view of the magnetic recording medium of the present invention. 1 is a magnetic recording layer, 2 is a nonmagnetic substrate, and 3 is a back lubricating layer.

In addition to this example, increase in bond strength between 1 and 2.2 and 3;
An intermediate layer for the purpose of preventing curling, etc., may have an M-retaining lubricating layer on the surface of the intermediate layer 1. Further, a high magnetic permeability layer may be provided under the l layer.

The magnetic recording layer 1 may be a coated type in which magnetic particles etc. are dispersed in an organic binder and applied, or a thin film type formed by a thin film deposition method such as a vacuum evaporation method, a sputtering method, or an ion blasting method. The thickness may be 0.5 to 10 JJ for the coated type, and 0.05 to 11 for the thin film type.
1.0 JLm is preferred.

As the material for the second non-magnetic substrate, polyimide, polyamide, polyethylene terephthalate (PET), etc. can be used. The thickness of the nonmagnetic substrate is preferably 3.0 to 30 mm.

The backside lubricating layer No. 3 is a thin film made of titanium nitride. TiN is an example of titanium nitride. As a method for forming it, titanium nitride may be directly deposited or sputtered, or titanium may be reactively sputtered or ion-bladed in an N2 or NH3 atmosphere. Regarding the thickness, if it is too thin, the effect of reducing friction will be small, and if the base film is thin, the stiffness of the tape will be low.
Envelope becomes bad. Moreover, especially in flexible media, if this layer is too thick, it will impair the flexibility of the media and will actually worsen the running stability. Thickness is lO
A number of A to 5000 A is preferable.

Further, titanium nitride has electrical conductivity, and a thin film formed without using an organic binder as in the present invention has high electrical conductivity and is highly effective in preventing static electricity.

In the present invention, especially when using a magnetic recording layer 1 formed by a thin film deposition method such as a vacuum evaporation method, a sputtering method, an ion blating method, or a plating method, a thinner base film than before is used, and the entire surface of the medium is Even when the thickness is reduced to about half of the conventional thickness, the necessary stiffness can be maintained and good reproduction output can be obtained. Use this to create a VTR
When tapes or audio tapes are created, tapes that are twice the length of conventional tapes can be stored in the same cassette half, which is an advantageous feature for long-term recording.

Hereinafter, the present invention will be specifically explained based on Examples.

[Example] As an example of the present invention, samples having the configurations shown in Table 1 were prepared. The following tests were conducted on these, and the results are also shown in Table 1. For comparison, samples with partially changed configurations were also prepared, and the test results are also shown in Table 1. In the table below, the material of the back lubricant layer in A to H is titanium nitride, the material of the back lubricant layer in I and J is a GaCO3 coating film, and the back lubricant layer in K is not provided.

All nonmagnetic substrates used were polyimide films. G
The o-Ni layer and the titanium nitride layer were formed by electron beam evaporation. However, for the Go-Ni layer, 02 gas was introduced during film formation and one surface was oxidized. For the titanium nitride layer, titanium nitride (TiN) pellets were used as a deposition source.

FIG. 2 shows the apparatus used to form the backside lubricating layer and recording layer by vacuum evaporation in this example. 4 is a vacuum chamber, 5 is an exhaust device, and the inside of vacuum chamber 4 is 3 x 1O-5T.
The pressure is reduced to below orr. The substrate film is transferred from an unwinding roll 6 to an intermediate free roller 7 to a cooling can 8. It passes through the intermediate free roller 7 again and reaches the winding roll 9. A pellet 10 of vapor deposition material is placed in a crucible 11 and heated by an electron beam emitted from an electron gun 12.

Note that when forming the recording layer of Co-old alloy, oblique evaporation is used, so the position of the crucible is on the left side of the figure.

The order of film formation is that the back lubricating layer is formed first, and then the recording layer is formed. In the case of samples I and J in which the back lubricant layer was formed by a coating method, the recording layer was deposited first, and then the back lubricant layer was formed.

The sample prepared as described above was cut into a 1000% wide tape, and a recording/playback test was conducted using a home VTR deck. FIG. 3 shows the rotating drum and the running path of the tape in its vicinity. The sample tape 14 runs along the guide pin 15, the rotating drum 1B, and the guide pin 15 again. 17 is a magnetic head attached to the rotating drum 1B. 3 on only one side of this magnetic head 17.
．． A 7 MHz sine wave signal was input and recorded, and the envelope of the reproduced output was observed using an oscilloscope. If the contact condition is constant throughout the area where the head and tape are in contact,
A rectangular envelope as shown in FIG. 4 is observed. In this figure, the vertical axis shows the playback voltage, and the horizontal axis shows time.If the contact between the head and the tape is not constant, an envelope such as a partial output drop as shown in Figure 5,
As shown in FIG. 6, an envelope in which the output changes irregularly is observed. The results of this test are shown in Table 1.
The case where a normal envelope as shown in FIG. 4 was observed was expressed as 0, and the case where it was not observed was expressed as x.

In sample I, an envelope as shown in FIG. 5 is observed. The reason for this is presumed to be that the substrate film is thin and the tape has insufficient stiffness. - 6th in 10,000, K
An envelope as shown in the figure is observed. The reason for this is presumed to be that the friction is large and the tension of the tape at the drum section is not stable.

Next, in order to confirm the effect of reducing friction, the coefficient of friction was measured using the apparatus shown in FIG. The sample 18 is set on the sample stage 18 with its back side up. A stainless steel stylus 20 is placed on top of this and moved relative to the sample, and the frictional force acting on the stylus is detected by a strain gauge. The tip of the stylus 20 has a spherical shape with a radius of 3 cm, and applies a load of 5 g. The moving speed of the stylus is 2 mts/sec. The results are shown in Table 1, and the relationship with the thickness of the titanium nitride layer is shown in FIG. 21 indicates the coefficient of friction of the polyimide film itself. The measurement results of the zero surface resistance value are shown in Table 1, and the relationship with the thickness of the titanium nitride layer is shown in FIG. The surface resistance of sample A varied greatly depending on the part of the sample to be measured, and a reliable value could not be obtained.

By using a titanium nitride layer of an appropriate thickness as the back lubricating layer, it is possible to reduce friction, compensate for the lack of stiffness, and obtain a normal tape-head contact situation. It can be seen that due to its high conductivity, it is also excellent in preventing static electricity.

[Effects of the Invention] As explained above, the medium of the present invention has excellent running stability due to reduced friction, antistatic properties, and optimization of stiffness, and at the same time, it is possible to reduce the winding wrinkles during the first manufacturing step. It has the property of being difficult to occur.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of an example of the magnetic recording medium of the present invention, Fig. 2 is a vapor deposition apparatus used to form the recording layer and back lubricating layer of the embodiment, and Fig. 3 is a rotating drum and tape in its vicinity. Running path, Figure 4 shows the normal output envelope, Figures 5 and 6 show the envelope when the contact between the head and tape is unstable, Figure 7 shows the friction coefficient measuring section, and Figure 8 shows the friction coefficient. FIG. 9 shows the relationship between the surface resistance value and the titanium nitride layer thickness. 1: Magnetic recording layer, 2: Non-magnetic substrate, 3: Back lubricating layer, 4: Vacuum chamber, 5: Exhaust device, 6: Unwinding roll, 7: Intermediate free roller, 8: Cooling can,
9: Take-up roll, 1O: Vapor deposition substance, 11 nil pot, 12: Electron gun, 13:
Anti-adhesion plate, 14: Sample tape. ! 5 guide pin, 16: rotating drum, 17: magnetic head, 18: sample, 13: sample stage, 20: stylus, 21: level of friction coefficient of polyimide resin film itself.

Claims (2)

[Claims] (1) A magnetic recording medium having a magnetic recording layer on one side of a non-magnetic substrate, and having a layer made of titanium nitride on the opposite side of the magnetic recording layer. (2) The magnetic recording medium according to claim 1, wherein the magnetic recording layer is formed by a thin film deposition method.