JPH087261A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To prevent the sticking of a degenerated body to the surface of a magnetic head at the time of high-speed sliding of the head on a coating type magnetic recording medium and to inhibit the rise of error rate due to the sticking. CONSTITUTION:When a magnetic layer based on magnetic powder and a binder is formed on a nonmagnetic substrate to obtain a magnetic recording medium, the magnetic layer is allowed to hold salicylaldoxime. Since the effect of salicylaldoxime is exhibited even in an environment at high temp. and low humidity, the resultant magnetic recording medium is very suitable for use as a magnetic tape on which a magnetic head slides at a high speed, e.g. a magnetic tape for the backup of a hard disk to which a helical scanning system is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium suitable for use as a backup recording medium for hard disks.

[0002]

2. Description of the Related Art In a computer, for example, as a recording / reproducing system of information, a magnetic disk device for directly writing / reading information necessary for calculation and a back-up of the information written on this magnetic disk are provided. A magnetic tape (data cartridge) device is usually installed together.

Among them, as a magnetic tape for backup, a magnetic paint prepared by dispersing and kneading a ferromagnetic powder, a binder, and various additives such as a dispersant and a lubricant in an organic solvent,
A so-called coating type magnetic recording medium in which a magnetic layer is formed by coating on a non-magnetic support such as a polyester film is used.

[0004]

By the way, since the backup magnetic tape recording / reproducing system is suitable for high-density recording, the magnetic head mounted on the rotary drum is obliquely scanned with respect to the running direction of the magnetic tape. The helical scan method is used for recording and reproducing.

However, in this helical scan system,
The magnetic head slides on the surface of the magnetic layer at high speed during recording and reproduction, as compared with the fixed head system in which the magnetic tape is run on the fixed head. Therefore, the surface of the magnetic head becomes hot due to the frictional heat at that time.

In the above-mentioned coating type magnetic recording medium, when the temperature of the magnetic head surface rises in this way, the organic substances such as the binder forming the surface of the magnetic layer become heat-transformed products and burn on the surface of the magnetic head. There is a large gap (spacing) between and. As a result, a predetermined signal output cannot be obtained and the error rate increases.

[0007] As a countermeasure against this, it has been devised that an abrasive is added to the magnetic layer so that the modified products burned on the surface of the magnetic head are sequentially scraped off by the abrasive. However, when an abrasive is added, its polishing power decreases, especially in a high-temperature and low-humidity environment, so that metamorphic compounds accumulate one after another and the error rate increases to a fatal level. Is desired.

Therefore, the present invention has been proposed in view of such a conventional situation, and even when recording / reproducing is performed by a helical scan method under a high temperature and low humidity environment, the magnetic layer originates from the magnetic layer. It is an object of the present invention to provide a magnetic recording medium in which a heat-transformed product is not burned and ellarate is suppressed to be low.

[0009]

DISCLOSURE OF THE INVENTION As a result of investigations by the present inventors to achieve the above-mentioned object, it was found that salicylaldoxime was present on the surface of a magnetic layer when sliding at high speed with a magnetic head. Therefore, it has been found that the transformation of the organic matter constituting the surface of the magnetic layer and the burning of the transformation on the surface of the magnetic head can be prevented, and the increase in the error rate can be suppressed.

The magnetic recording medium of the present invention has been completed on the basis of such findings, and a magnetic recording comprising a non-magnetic support, on which a magnetic layer mainly composed of magnetic powder and a binder is formed. In the medium, salicylaldoxime is held in the magnetic layer.

The magnetic recording medium to which the present invention is applied is a so-called coating type magnetic recording medium in which a magnetic layer mainly composed of magnetic powder and a binder is formed on a non-magnetic support.

In the present invention, salicylaldoxime is held in the magnetic layer of such a coating type magnetic recording medium. When the salicylaldoxime is held in the magnetic layer, it is possible to prevent the metamorphism of the organic material forming the surface of the magnetic layer and the seizure of the metamorphism on the surface of the magnetic head which occur when the magnetic head slides at high speed. This effect is similarly exhibited in a high temperature and low humidity environment where the effect is reduced by the abrasive. Therefore, an increase in the error rate caused by burn-in of the modified material on the surface of the magnetic head can be suppressed regardless of the environment of use.

The salicylaldoxime may be present on the surface of the magnetic layer that slides on the magnetic head. Therefore, salicylaldoxime may be added to the magnetic coating material in advance so as to be internally added directly to the magnetic layer, or may be applied to the surface of the magnetic layer.

When salicylaldoxime is internally added to the magnetic layer, the internal addition amount is preferably 0.3 to 5 parts by weight with respect to 100 parts by weight of the magnetic powder. When salicylaldoxime is applied to the surface of the magnetic layer, the amount applied is preferably 10 to 100 mg / m ² .

If the amount of salicylaldoxime internally added to the magnetic layer or the amount of deposition is less than the above range, the effect is insufficient, and if it exceeds the above range, there is a problem such as powder falling. There is fear.

As described above, in the magnetic recording medium of the present invention, salicylaldoxime is retained in the magnetic layer, but as a non-magnetic support on which the magnetic powder constituting the magnetic layer, the binder and the magnetic layer are formed. Any of those normally used in this type of magnetic recording medium can be used.

The magnetic powder may be oxide magnetic powder.
Alternatively, it may be a metal magnetic powder. As oxide magnetic powder
Γ-Fe₂O₃, Co-containing γ-Fe₂O₃, Fe
₃O _Four, Co-containing γ-Fe₃O_Four, Co deposition-Fe₃O
_Four, CrO₂Etc. As the magnetic metal powder,
Fe, Co, Ni, Fe-Co, Fe-Ni, Fe-C
o-Ni, Co-Ni, Fe-Co-B, Fe-Co-
Cr-B, Mn-Bi, Mn-Al, Fe-Co-V, etc.
To further improve these various properties.
Gold such as Al, Si, Ti, Cr, Mn, Cu, Zn
The genus component may be added. Also Baliu
Hexagonal ferrite such as muferrite and iron nitride are also used
It is possible.

As the binder, an organic binder such as vinyl copolymer, polyester polyurethane, polycarbonate polyurethane, nitrocellulose or the like can be used.

In addition to these binders and magnetic powders, additives such as a lubricant, an abrasive and an antistatic agent may be added to the magnetic layer, if necessary. Any conventionally known materials can be used as these additives, and the additives are not limited at all.

As the non-magnetic support, polyethylene terephthalate film, polyethylene naphthalate film, aramid (aromatic polyamide) film, etc. can be used.

[0021]

In a magnetic recording medium having a magnetic layer mainly composed of magnetic powder and a binder formed on a non-magnetic support,
When the salicylaldoxime is held in the magnetic layer, it is possible to prevent the transformation of the organic material constituting the surface of the magnetic layer and the seizure of this transformation on the surface of the magnetic head, which occurs when the magnetic head slides at a high speed. This effect is similarly exhibited especially in a high temperature and low humidity environment where the effect of the abrasive is reduced. Therefore, an increase in the error rate caused by burn-in of the modified material on the surface of the magnetic head can be suppressed regardless of the use environment.

[0022]

EXAMPLES Preferred examples of the present invention will be described below based on experimental results.

Example 1 This example is an example in which salicylaldoxime is internally added to the magnetic layer.

According to the following composition, various magnetic coating compositions were weighed out, mixed and dispersed in a sand mill for 4 hours to prepare magnetic coating compositions.

Composition of magnetic paint Metal (Fe) magnetic powder (specific surface area 50 m ² / g) 100 parts by weight Polyester polyurethane 8 parts by weight (Nipporan, trade name N-2304) Vinyl chloride-vinyl acetate copolymer (VAGH) ) 8 parts by weight Carbon black (trade name # 50 manufactured by Asahi Carbon Co., Ltd.) 4 parts by weight Alumina (trade name AKP-50) 8 parts by weight Butyl stearate 2 parts by weight Methyl ethyl ketone 150 parts by weight Toluene 70 parts by weight

4 parts by weight of the hardener Coronate L, 1 part by weight of myristic acid and 2 parts by weight of salicylaldoxime were added to this magnetic paint, and a polyethylene terephthalate (PET) film having a thickness of 7 μm and a thickness of 3 μm was added.
Was applied. Next, the formed magnetic coating film was calendered, and then left in an oven at a temperature of 60 ° C. for 20 hours to form a magnetic layer.

Next, various backcoat layer compositions were measured according to the following composition and mixed and dispersed in a ball mill for 24 hours to prepare a backcoat paint.

Composition of back coat paint Carbon black (Asahi Carbon Co., Ltd., trade name # 50) 100 parts by weight Polyester polyurethane 100 parts by weight (Nipporan Co., trade name N-2304) Methyl ethyl ketone 500 parts by weight Toluene 500 parts by weight

To this back coat paint, 20 parts by weight of a hardener Coronate L is further added, and the non-magnetic support is coated with a thickness of 0.7 μm on the side opposite to the side on which the magnetic layer is formed. To form a back coat layer.

Then, the tape raw material on which the magnetic layer and the back coat layer were respectively formed was cut into a width of 8 mm to form a sample tape, which was incorporated into a data 8 mm shell.

Example 2 This example is an example in which salicylaldoxime is deposited on the surface of the magnetic layer.

A sample tape was prepared in the same manner as in Example 1 except that the salicylaldoxime was not added to the magnetic paint and the ethanol solution of 0.5% salicylaldoxime was applied to the surface of the magnetic layer. Created, data 8
Incorporated into the millishell.

Comparative Example 1 A sample tape was prepared in the same manner as in Example 1 except that salicylaldoxime was not added to the magnetic paint, and the tape was incorporated into a data 8 millishell.

Each of the sample tapes manufactured as described above was subjected to a standard running durability test which is usually performed on a data storage medium and data of 8 mm.

That is, the running durability test was conducted at a temperature of 45.
Under high temperature and low humidity environment of ℃, 30% RH, drive device (EX
The sample tape was run for 50 passes with ABYTE, trade name EXB-8500), and the block error rate at that time was measured to evaluate.

However, the number of passes mentioned here is the number of times the following process is performed. 1 Write data over 32000 blocks. 2 Rewind and return to the initial position. 3 Read the written data of 32000 blocks. 4 Rewind and return to the initial position.

The block error rate is 320
It is the ratio (%) of blocks that cannot be normally written or read out of the 00 blocks.

Table 1 shows the block error rate of the first pass and the block error rate of the 50th pass measured as described above.

[0039]

[Table 1]

As shown in Table 1, the sample tape of Example 1 in which salicylaldoxime (SA) was internally added to the magnetic layer and the sample tape of Example 2 in which salicylaldoxime was applied to the surface of the magnetic layer were: In both cases, even if the block error rate is 50th pass, it is suppressed to a low value which is the same as that of the 1st pass.

On the other hand, the sample tape of Comparative Example 1 in which salicylaldoxime was not held in the magnetic layer was
The block error rate on the 50th pass is as high as 5.3%.

From the above, it is effective to retain salicylaldoxime in the magnetic layer in order to suppress an increase in block error rate caused by high-speed sliding of the magnetic head, and this effect is exhibited even in a high temperature and low humidity environment. I knew it would be done.

[0043]

As is apparent from the above description, in the present invention, a magnetic recording medium comprising a non-magnetic support and a magnetic layer mainly comprising magnetic powder and a binder is formed on the magnetic recording medium.
Since the salicylaldoxime is held in the magnetic layer, burn-in of the metamorphism on the surface of the magnetic head, which is caused when the magnetic head slides at high speed, is prevented, and the metamorphosis is burned on the surface of the magnetic head. The increase in error rate can be suppressed. Further, this effect is similarly exhibited even in a high temperature and low humidity environment.

Therefore, it can be said that the magnetic recording medium of the present invention is extremely suitable as a magnetic tape on which a magnetic head slides at a high speed, such as a magnetic tape for backup of a hard disk to which a helical scan method is applied.

Claims (3)

[Claims] 1. A magnetic recording medium comprising a non-magnetic support and a magnetic layer mainly composed of magnetic powder and a binder, wherein salicylaldoxime is retained in the magnetic layer. And a magnetic recording medium. 2. The magnetic recording medium according to claim 1, wherein 0.3 to 5 parts by weight of salicylaldoxime is internally added to 100 parts by weight of the magnetic powder in the magnetic layer. 3. Salicylaldoxime is formed on the surface of the magnetic layer.
10-100mg / m ²To be applied in a certain amount
The magnetic recording medium according to claim 1, wherein the magnetic recording medium is a magnetic recording medium.