JPS6047229A - Tape shape magnetic recording medium - Google Patents

Abstract

PURPOSE:To attain durability of a tape shape magnetic recording medium by the constitution that a magnetic recording layer is formed by a ferro-magnetic metallic thin film and a lubricant layer on the magnetic recording layer has a maximum lubricant amount at the end in the broadwise direction of a support. CONSTITUTION:Both ends of the medium are susceptible to damage with abnormal friction due to contact occasionally taken place by a rotary cylinder and a magnetic head in the repetitive use in a V.T.R. but the friction force is reduced remarkably by applying lots of lubricant to the region, then the durability performance is improved. The lubricant layer 5 consists of an end part lubricant layer 4B arranged on the surface at the side slided to the magnetic head and the cylinder of a magnetic recording layer 2, and a central part lubricant layer 4A (parts other than the ends are called the center part). The distribution state of the lubricant can be continuous film or island form discontinuous film which has been known in the field of the thin film technology.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tape-shaped magnetic recording medium whose recording layer is a ferromagnetic metal thin film suitable for short wavelength recording.

Structure of conventional example and its problems Figure 1 is a diagram showing a cross section of a conventional tape-shaped magnetic recording medium (referred to as V, lower magnetic tape), in which 1 is a support, 2 is a magnetic recording layer, and 3 is a lubricant layer. .

Recording all information using this magnetic tape is a well-known technique, but in recent years, the magnetic recording layer 2 has become thinner and thinner in order to record at higher density. In line with this, it is important to protect the lubricant layer 3, especially to improve the scratch resistance when used in helical scanning magnetic recording devices (J"), referred to below as V, T, and R. In addition to changing the construction methods, consideration has also been given to construction methods, including scratch resistance under high temperature and high humidity conditions.

Driving stability is not sufficient.

Therefore, when used for wind recording, problems such as increased dropouts due to repeated use and screen fluctuations due to unstable running have occurred. This problem occurs because in order to perform short wavelength recording, it is necessary to bring the magnetic recording layer and the magnetic head, which has a narrow gap width, into close contact with each other, making it impossible to increase the thickness of the lubricant layer to reduce friction. If the lubricant layer is made thicker, the durability improves, but on the other hand, the spacing loss increases and the reproduction output is significantly reduced, making high-density magnetic recording impossible. On the other hand, the lubricant layer is set to a thickness within the range where the spacing loss is small. Then V, T, R,
This problem occurred because optimization through adjustment could not be performed, which meant that the number of times the device could be used was significantly reduced, making it unable to provide sufficient practical performance.

Object of the Invention The present invention aims to improve the durability of a tape-shaped magnetic recording medium having a magnetic recording layer made of a ferromagnetic metal thin film. The present invention also provides a tape-shaped magnetic recording medium (hereinafter referred to as magnetic tape), characterized in that the lubricant layer on the magnetic recording layer has a maximum amount of lubricant at the ends in the width direction of the support.

DESCRIPTION OF THE EMBODIMENTS In the present invention, the end portions are 11111 inward from both ends of the magnetic recording layer as shown schematically in the cross section of the magnetic tape in FIGS. 2 and 3.
This refers to an area that extends 1 mm, preferably about 0.6 mm, into the area.

When this area is used for V, T, and R, it is not used for recording and reproducing video signals, so increasing the amount of lubricant in this area will not cause an increase in space gloss.
, T, R, and when used repeatedly, both ends are susceptible to damage due to abnormal friction caused by occasional contact between the magnetic head and rotating cylinder, but by increasing the amount of lubricant in these areas, the friction force can be significantly reduced. This can be considered to improve durability performance.

In FIG. 2, the lubricant layer 5 is arranged on the surface of the magnetic recording layer 2 on the side that comes into sliding contact with the magnetic head and the cylinder. ), and in Fig. 3, the lubricant layer 7
The surface of the magnetic recording layer 2 is composed of an edge lubricant layer 6B, a center lubricant layer 6A, and a cut side lubricant layer 6C of the magnetic recording layer 2.

Note that the cut side surface lubricant layer 6C may be configured to completely cover the entire cut side surface of the support 1.

The distribution state of the lubricant of the present invention may be a continuous film as schematically shown in FIGS. 2 and 3, or may be an island-shaped discontinuous film well known in the field of thin films.

However, the lubricant amount distribution state schematically shown in FIGS. 2 and 3 is not step function-like as shown in FIG. 4(a),
Rather, it often changes continuously, as shown as examples in FIGS. 4(b) to 4(d).

Therefore, the present invention includes the case where there are more end portions than the average value per unit length in the width direction of the end portions and the center portion.

As a more extreme case, a lubricant is provided only at the end portions, which is also within the scope of the present invention.

The support used in the present invention is a flexible polymer film made of polyethylene terephthalate, polyethylene naphthalate, polypropylene, polyamide, polyimide, polyacrylamide, cellulose triacetate, polycarbonate, etc. A polymer film with an undercoat layer may also be used. Further, the undercoat layer can be made of either a nonmagnetic material or a soft magnetic material.

The ferromagnetic metal thin film that becomes the magnetic recording layer in the present invention is made of Fe, C
o, Fe-Co, Co-Ni, Fe-3i, F
e-Rh'.

Co-P, Co-B, Co-8i, Co-
V, Co-Mo, Co-W.

Co-Y, Co-La, Co-Ru, Go-
Ce, Co-Mg.

Co-Ca, Co-3m, Co-Zr,
Co-Mn, Co-Ti.

Co-Cr, Co-Ni-Cr, Co-N1-Mo
, Co-Ni-Mg, Co-Ni-Re, Co-
Cr-Pt, Co-Ni-Cr-Mg, Co-Ni
- Vacuum deposited film such as Cr-Rh, vapor deposited film in gas, sputtered film, ion blating film, coating film, chemical vapor deposition film, etc.
Such as tsuki membrane.

The lubricants that can be used in the present invention include those whose basic effect is not only to provide lubricity but also to play the role of preventing rust by repelling water.

The lubricant is fatty acid, fatty acid ester, mineral oil, higher alcohol, etc., and the coating method is to use a doctor blade, reverse roll, squeeze, kiss, etc. coating machine, or by plasma deposition, vacuum deposition, plasma polymerization, etc. It can also be done by

Examples will be described in more detail, but it goes without saying that the present invention is not limited to these examples.

The magnetic recording layer used in the example was a co-Cr perpendicularly magnetized film, which was coated on a polyethylene terephthalate film with a thickness of 11.5 μm using a high-frequency snow tuttering method to obtain a perpendicular coercive force film containing 20.3% of Cr. Thickness Q of 66Q [○e]
, a Co--Cr thin film of 19 μm, and the surface roughness of the branch body used was 0.04 μm.

The evaluation of the Examples and Comparative Examples was carried out by placing the test cylinders in various test environments such as V, T, R, and i with cylinder diameters of 40 scales, and checking the image quality in repeated runs. The tape width was 8.

[Example 1] Myristic acid dissolved in methyl ethyl ketone was applied to the entire width of a tape having a width of 8 mm so that the dry thickness was 40 mm.

In this state, at both ends, within a range of about 0.6rmn from the end,
The entire solution was applied again. The coating was applied so that the total dry thickness was 90 mm.

Regarding the lubricant distribution of this magnetic tape, some re-dissolution phenomenon occurred during recoating, and actual measurements showed that the average thickness was 80 mm and the thickness increased from the edge by about 0.8 mm.

[Example 2] A Co--Cr thin film with a width of 50 cm was disposed. The entire support was bent over and a solution of myristate in t-methyl ethyl ketone was applied to the entire support to a dry thickness of about 4.8 mm.

Next, the coater head was specially processed, and a solution of myristic acid dissolved in acetone was applied with a coating width of 1 stage to a dry thickness of 60 mm using a center-to-center distance of 8 cylinders, and an in-position coating of 8 mm Cut to width.

The lubricant distribution of this magnetic tape had an average thickness of 858 mm in the region of 0.6 to 0.8 mm at both ends.

[Example 3] Zinc stearate dissolved in all toluene was applied to a tape 8 mm wide so that the dry thickness reached 55 mm.

Next, apply zinc stearate dissolved in methyl ethyl ketone to both ends within 0.3 mm from the end to a dry thickness of 55 mm.
I applied it to make it look like a person.

The lubricant distribution of this magnetic tape was about a from both ends, and the average film thickness up to 5ml+ was 958.

[Comparative example]

Examples 1 to 3 in which the lubricant was not reapplied to the edges were compared with Comparative Example 1. Comparative example 2. This was designated as Comparative Example 3.

The evaluation results are shown in Tables 1 and 2 below. The image quality evaluation ranks are: ◎...no problems at all, ○...dropouts are slightly noticeable, △...the screen sometimes shakes slightly, ×...
...Displayed below the practical level.

(Margins below) It is clear from Table 2 and above that the magnetic tape of this example has a durability of 200 passes even in various practical environments, compared to the conventional magnetic tape which could only have a durability of about 50 passes. It can be said that it has durability.

Effects of the Invention The tape-shaped magnetic recording medium of the present invention maintains excellent reproduced image quality even after repeated use.

Specifically, in repeated use in recording experiments with helical scan V, T, and R, there is no increase in jitter components, no stiffness of the medium at posts, cylinders, etc., and no increase in dropouts. , image quality can be maintained because there is no change in high frequency output.

Therefore, according to the present invention, even higher density magnetic recording can be put to practical use.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional magnetic recording medium, and FIG. 2 is a cross-sectional view of a conventional magnetic recording medium. FIG. 3 is a sectional view of the tape-shaped magnetic recording medium of the present invention, and FIG.
Figures (a) to (d) are examples of lubricant landscape distribution charts in the width direction of a tape-shaped magnetic recording medium. 1...Support, 2...Magnetic recording layer, 3
, 5.7...Lubricant layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4 Diagram 4: Line '5

Claims (1)

[Claims] The magnetic recording layer on the support is a ferromagnetic metal thin film, and the lubricant layer on the magnetic recording layer has a structure in which the amount of lubricant is maximum at the ends in the width direction of the support. A tape-shaped magnetic recording medium.