JPS6154044A - Manufacture and its device of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a recording medium excellent in anticorrosion without the drop of a magnetic characteristic by making the steam flow of a ferromagnetic material incident on a basic material, which moves from a high incident angle part to a low one along the peripheral side of a cylindrical can, so that the maximum incident angle of the steam flow can be within a specific range. CONSTITUTION:While a basic material 4 such as plastic film is shifted along the peripheral side of a cylindrical can 3 from an original tape roll 5 and wound to a winding roll, the steam flow shielding top 10a of a buffer plate 10 is arranged and disposed along the peripheral side of the can 3 to execute the vacuum deposition so that a maximum incident angle (alpha) of the steam flow A of a ferromagnetic material 8 can be within a range of 75-85 deg. with use of a minimum incident angle adjusting buffer plate 9 and a maximum incident angle adjusting buffer plate 10. Thus the particle size of a ferromagnetic material particle precipitated on the basic material 4 is made larger, while a space between magnetic particles in the vicinity of an interface between the basic material and a magnetic metallic thin film is made smaller: therefore the anticorrosion of a magnetic layer wherein the corrosion develops due to a corrosive component such as water in the air for entering the space can be improved. Moreover a minimum incident angle (beta) of said plate 9 is set over 45 deg. to improve the coercive force, thereby enhancing a magnetic characteristic.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a magnetic recording medium having a ferromagnetic metal thin film layer as a recording layer, and an apparatus used for carrying out the method, and more particularly, to The present invention relates to a method for manufacturing the above-mentioned magnetic recording medium having excellent corrosion resistance, and an apparatus used for carrying out the method.

[Conventional technology]

Magnetic recording media with a ferromagnetic metal thin film layer as the recording layer are usually made by moving a base such as a polyester film along the circumferential side of a cylindrical can installed in a vacuum chamber, and then coating the base with a ferromagnetic material. It is made by vacuum evaporation, etc.
In order to improve magnetic properties, it is widely practiced to perform oblique incident deposition by adjusting the minimum incident angle. [Kyuzo Nakamura, 3 others, 28th Applied Physics Association Lectures, Proceedings, P470 (1981)] [Problems to be solved by the invention] However, by adjusting this conventional minimum angle of incidence, Although the oblique incidence deposition method increases the coercive force and improves the magnetic properties, the particle size of the ferromagnetic material particles deposited on the substrate to form the ferromagnetic metal thin film layer is extremely small, and The gaps between the ferromagnetic material particles near the interface with the ferromagnetic metal thin film layer are extremely large, so if left in the atmosphere, they will react with moisture and chlorine in the atmosphere and corrode, causing problems such as saturation magnetic flux density. The disadvantage is that the magnetic properties deteriorate.

[Means for solving problems]

This invention was made as a result of various studies to improve this drawback, and includes a deposition prevention plate inside the vacuum chamber that adjusts the minimum angle of incidence, and adjusts the maximum angle of incidence within the range of 75 degrees to 85 degrees. A new adhesion prevention plate has been installed to increase the maximum angle of incidence of the ferromagnetic material vapor flow from the ferromagnetic material evaporation source to the substrate from 75 degrees.
By setting the angle within the range of 85 degrees, the particle size is large.
To form a ferromagnetic metal thin film layer made of ferromagnetic material particles with a small specific surface area, and to reduce the gap between the ferromagnetic material particles near the interface between the substrate and the ferromagnetic metal thin film layer, so as not to significantly reduce magnetic properties. However, the corrosion resistance has been sufficiently improved.

The present invention will be described below with reference to the drawings.

Figure 1 shows a cross-sectional view of the vacuum evaporation apparatus,
is a vacuum chamber, and the inside of this vacuum chamber 1 is maintained in a vacuum by an exhaust system 2. Reference numeral 3 denotes a cylindrical can disposed in the center of the vacuum chamber 1, and a substrate 4 such as a plastic film is moved along the circumferential side of the cylindrical can 3 from a raw roll 5, and is transferred to a take-up roll 6. It is wound up. During this time, the ferromagnetic material 8 is heated and evaporated in the ferromagnetic material evaporation source 7 disposed at the bottom of the vacuum chamber 1, facing the base 4 moving along the circumferential side of the cylindrical can 3, and this vapor flow A is Due to the effects of the minimum incidence angle adjustment adhesion prevention plate 9 disposed below near the cylindrical can 3 and the maximum incidence angle adjustment adhesion prevention plate 10 disposed from the side to the bottom near the cylindrical can 3, 4 is obliquely incident evaporated. Here, the maximum incident angle adjustment adhesion prevention plate 10 is configured such that its vapor flow blocking tip surface 10a is attached to the circumferential surface of the cylindrical can 3 so that the maximum incident angle α of the vapor flow A is within the range of 75 degrees to 85 degrees. It is preferable to extend the vapor flow along the vapor flow blocking tip surface tOa of the deposition prevention plate 10 arranged in this way, and perform vacuum evaporation with the maximum incident angle α within the range of 75 degrees to 85 degrees. , the particle size of the ferromagnetic material particles deposited on the substrate 4 to form the ferromagnetic metal thin film layer becomes larger, and the gap between the ferromagnetic material particles near the interface between the substrate and the ferromagnetic metal thin film layer becomes smaller. , corrosion resistance is improved. On the other hand, if the maximum incident angle α of the steam flow A becomes smaller than 75 degrees, corrosion resistance is improved but sufficient coercive force cannot be obtained;
When the angle is greater than 5 degrees, the particle diameter of the ferromagnetic material particles becomes smaller, and the gap between the ferromagnetic material particles near the interface between the base and the ferromagnetic metal thin film layer becomes larger, resulting in a high coercive force. In addition, the minimum incident angle β of the vapor flow A, which is partially blocked and adjusted by the minimum incident angle adjustment adhesion prevention plate 9, is not sufficient for magnetic recording with sufficiently high coercive force and excellent magnetic properties. In order to obtain a medium, the angle is preferably 45 degrees or more. Note that 11 in the figure is a gas introduction pipe.

As described above, the magnetic recording medium manufacturing apparatus of the present invention has the minimum incident angle adjusting adhesion prevention plate 9 disposed near the cylindrical can 3 disposed in the vacuum chamber 1, and A maximum incidence angle adjustment adhesion prevention plate 10 is newly installed to adjust the maximum incidence angle within the range of 75 degrees to 85 degrees, and the vapor flow A of the ferromagnetic material 8 from the ferromagnetic material evaporation source 7 to the base 4 is increased. Since the maximum incident angle of The gaps between the ferromagnetic material particles near the interface with the layer also become smaller, resulting in a magnetic recording medium with good magnetic properties and excellent corrosion resistance.

As the substrate, a plastic film made of commonly used polymer moldings such as polyester, polyimide, polyamide, etc. and a metal film made of non-magnetic metal such as copper are used. Materials include ferromagnetic metals such as GO%Ni- and Fe, alloys or oxides containing a small amount of these ferromagnetic metals (alloys or oxides containing one of these metals, and Co-P,
Any ferromagnetic material commonly used for vacuum deposition may be used, such as a compound with a ferromagnetic metal such as Co--N1-P.

In addition, as magnetic recording media, polyester film,
Includes various forms of structures that come into sliding contact with magnetic heads, such as magnetic tapes based on plastic films such as polyimide films, magnetic disks and magnetic drums based on disks and drums made of plastic films, aluminum plates, glass plates, etc. do.

〔Example〕

, Next, embodiments of the present invention will be described.

Example Using the vacuum evaporation apparatus shown in FIG. At the same time, cobalt 8 was added to the evaporation source 7. Next, the traveling speed of the polyester film 4 was adjusted within the range of 20 to 25 m/min, and the inside of the vacuum chamber 1 was pumped with about 5XIO-6 by the exhaust system 2. ) - 120cc of oxygen gas is evacuated from the gas introduction pipe 11.
Cobalt 8 was introduced at a flow rate of /min, and the degree of vacuum was set to 9 x 10-5) to heat and evaporate cobalt 8, and the maximum incident angle α and the minimum incident angle β were varied as shown in Table 1 below.
A ferromagnetic metal thin film layer made of cobalt and having a thickness of 1500 nm was formed on the polyester film 4 by performing oblique incidence deposition. After that, it was cut into a predetermined width to make a large number of magnetic tapes.

The magnetic tapes obtained in the Examples in Table 1 were measured for coercive force and tested for corrosion resistance. Corrosion resistance test: 60°C 190%
The magnetic tape obtained in the RH atmosphere was left standing for one week, and the saturation magnetic flux density If was measured after the standing, and the initial saturation magnetic flux density 1. The deterioration rate from is expressed as ((Io I+)/Io)X
It was calculated from 100.

Table 2 below shows the results.

Table 2 [Effects of the Invention] As is clear from the above table, the magnetic tapes obtained with Samples 2 to 4 and 7 to 10 have higher coercive force than the magnetic tapes obtained with Samples 5 and 6. (Also, compared to the magnetic tape obtained in Sample 1, the deterioration rate of the saturation magnetic flux density is small. Therefore, according to the manufacturing method and apparatus of the present invention, the magnetic tape has good magnetic properties and further improved corrosion resistance. It can be seen that a recording medium is obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a magnetic recording medium manufacturing apparatus of the present invention. DESCRIPTION OF SYMBOLS 1... Vacuum chamber, 3... Cylindrical can, 4... Substrate, 7... Ferromagnetic material evaporation source, 8... Ferromagnetic material, 9...
- Deposition prevention plate for adjusting the minimum incident angle, 10... Deposition prevention plate for adjusting the maximum incidence angle, A... Vapor flow, α... Maximum incident angle, β.
...Minimum angle of incidence patent applicant Hitachi Maxell Ltd. Figure 1

Claims (1)

[Claims] 1. A base that moves a vapor flow of a ferromagnetic material evaporated from an evaporation source from a high incidence angle part to a low incidence angle part along the circumferential side of a cylindrical can in a vacuum atmosphere. A method for manufacturing a magnetic recording medium in which the vapor flow of the ferromagnetic material is deposited with oblique incidence, the method comprising: setting the maximum angle of incidence of the vapor flow of the ferromagnetic material within the range of 75 degrees to 85 degrees; In a vacuum chamber, there is a cylindrical can, a substrate that moves along the circumferential side of the cylindrical can from a high incidence angle part to a low incidence angle part, and a substrate that moves along the circumferential side of this cylindrical can and is opposed to it. In a magnetic recording medium manufacturing apparatus equipped with a ferromagnetic material evaporation source and an adhesion prevention plate that partially blocks the vapor flow of the ferromagnetic material from the ferromagnetic material evaporation source to the substrate, the adhesion prevention plate is installed. The deposition prevention plate is divided into a deposition prevention plate for adjusting the minimum incident angle and a deposition prevention plate for adjusting the maximum incidence angle, and the deposition prevention plate for adjusting the minimum incidence angle is placed in the low incidence angle part near the cylindrical can, and the deposition prevention plate for adjusting the maximum incidence angle is The adjustment anti-adhesion plate is arranged at a position where the maximum incidence angle of the high incidence angle part is within the range of 75 degrees to 85 degrees, and the maximum incidence angle of the vapor flow of the ferromagnetic material is within the range of 75 degrees to 85 degrees. A magnetic recording medium manufacturing apparatus characterized by: