JPS6326826A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To eliminate thermal damages in spite of vapor deposition on both faces by executing vapor deposition while a high-polymer film is moved along a rotary support having the hardness lower than the hardness of the vapor deposited film which contacts the rotary support at the time of subjecting another surface of the high-polymer film to the vapor deposition after forming the vapor deposited film on one face thereof. CONSTITUTION:A ferromagnetic metallic layer 2 to be formed as the magnetic recording layer is provided atop the high-polymer film 1 consisting of a polyester film or the like and the magnetic recording layer or nonmagnetic thin film 3 is formed on the bottom surface. Lubricating agent layers 4, 5 are provided on the layers 2, 3. In order to form such medium, a film from an untreated roll 6 is subjected to the vapor deposition with a 2st cooling can 8 by a 1st vapor source 9 through a mask 10 and is then subjected to the vapor deposition at the place of the 2nd cooling can 11 by the vapor flow 15 from a 2nd vapor source 13 through a mask 14. A mounting ring 12 is made of a material having the hardness lower then the hardness of the vapor deposited film formed by the vapor source 9. For example, Cu having 100mum thickness is formed on a cylinder made of a stainless steel and the film having the hardness differing by >=100 in micro-Vickers hardness from the hardness of the vapor deposited film is used.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a double-sided vapor-deposited magnetic recording medium having a vapor-deposited magnetic recording layer suitable for high-density magnetic recording.

2. Description of the Related Art In recent years, there has been active development of magnetic tapes and magnetic disks as high-density magnetic recording media, each of which uses a ferromagnetic metal thin film as a magnetic recording layer. The core of manufacturing this type of magnetic recording medium is the winding deposition technique, and how to obtain desired magnetic properties at high speed is recognized as an ongoing issue and improvements have been made. As is well known, polyethylene terephthalate film is used as a base film for magnetic tapes, floppy disks, etc. When a magnetic recording layer is deposited directly on this film or via an underlayer with an electron beam, it is common to cool the film along a cooling can and perform oblique deposition continuously. It is thought that it is important to intervene with oxygen.

Experimentally, it is possible to use an expensive heat-resistant film [Japanese Unexamined Patent Application Publication No. 138068/1984], but in order to advance practical application, it is necessary to establish cooling conditions that do not cause thermal deformation or thermal damage of polyethylene terephthalate. Currently, a design has been devised in which a refrigerant at a temperature of 0°C or lower, preferably -20°C or lower, is circulated through a cooling can with a mirror-finished, highly hard surface to efficiently remove the heat received by the film. ing.

On the other hand, a vapor-deposited tape (hereinafter M
E-tape) is expected to improve the volume recording density by making it thinner, and double-sided vapor-deposited type is being considered in order to prevent tape deformation and increase mechanical strength (Japanese Patent Laid-Open No. 61-50).
219.61-85618.61-11o343), using a heat-resistant film, using a small-scale evaporation source with low thermal radiation, and using a thick polyester film have achieved some success.

Problems to be solved by the inventionHowever, 10. When manufacturing magnetic recording media by high-speed vapor deposition using a polyester substrate with a thickness of t1m or less, the coolant circulating in the cooling can is heated to a temperature of -30°C to -4°C.
Even at 0° C., the polyester substrate may be thermally damaged and long media cannot be stably obtained, which is a problem that is desired to be improved.

The present invention has been made in view of the above-mentioned circumstances, and provides a method for manufacturing a double-sided deposition type magnetic recording medium that is free from thermal damage.

Means for Solving the Problems In order to solve the above-mentioned problems, the method for manufacturing a magnetic recording medium of the present invention includes forming a vapor deposited film on one side of a polymer film and then depositing it on the other side. The vapor deposition is carried out along the rotating support whose hardness is lower than that of the vapor-deposited film in contact with the rotating support.

Effect: The method for producing a magnetic recording medium of the present invention has the above-described configuration, and by significantly increasing the effective contact area between the rotating support and the previously deposited film, it is possible to achieve This allows for sufficient cooling of the polymer film, making it possible to perform vapor deposition on both sides of the polymer film without thermal damage.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an enlarged cross-sectional view of a magnetic recording medium manufactured according to the present invention, in which 1 is a polymer film such as a polyester film, 2 is a ferromagnetic metal thin film serving as a magnetic recording layer, and 3 is a magnetic recording layer or a non-magnetic recording layer. 4.5 is a lubricant layer of the magnetic thin film.

Fig. 2 is a drawing of the internal structure of the vapor deposition apparatus used to carry out the present invention, in which 6 is an untreated polymer film roll, 7 is an untreated polymer film roll;
is a roll of treated polymeric film. 8 is a first cooling can, 9 is a first evaporation source, and 10 is a mask. 11 is the second cooling can, 12 is the mounting ring, 1
3 is a second evaporation source, 14 is a mask, 15 is a vapor flow, 16 is an adhesion prevention plate, and 17 is a free roller.

The mounting ring 12 is unnecessary because it is made of a material that is softer than the hardness of the evaporated film formed by the operation of the evaporation source 9, and it is preferable that the difference in micro-Vickers hardness is 100 or more. The first cooling can was made of hard chrome-plated stainless steel with a diameter of 50 mm, while the second cooling can was a stainless steel cylinder with a diameter of 50 m and coated with copper with a thickness of 10,077 m. On polyethylene terephthalate film with thickness Bpm K
, circulating a 10°C hot medium in the first cooling can,
1' x 10-' (Torr) of oxygen to form a silicon oxide film of 0.2171 m,
Subsequently, CoNi (Ni 20 wt%) was applied to the opposite surface at a minimum incidence angle of 43 degrees in a second cooling can at a temperature of 0.16/jm in 1 × 10-' (Torr).
Diagonally deposited. At this time, the second cooling can is 0°C.
The zero line speed with circulating refrigerant is 50 m/
The reproduction output recorded at a recording wavelength of 00.75 μm obtained by performing double-sided deposition with a length of 4000 m at m t n three times is as follows:
The heat damage was uniform within 1 (dB) in both the width and length directions, and there was no heat damage at all.

As a comparative example, the second cooling can was made of the same hard chrome-plated stainless steel as the first cooling can, and -
Double-sided deposition was performed under the same conditions by circulating a coolant at 26° C. As a result, there were 13 locations over a distance of 4000 m where wavy wrinkles occurred and where heat damage caused significant melting.

In addition, in order to compare the tape, a lubricant layer made of stearic acid was used in which about 40 lubricant layers were placed on the vapor deposited film.For the vapor deposited film, a magnetic recording layer may be formed first, or Both sides may be magnetic recording layers, and in either case, the cooling effect can be improved by making the hardness of the surface used as a rotating support in the second vapor deposition smaller than the hardness of the vapor deposited film obtained in the first vapor deposition. Large and stable. Therefore, not only polyethylene terephthalate but also other polymer films,
This means that double-sided deposition can be performed without the need to increase the size of the refrigerant device and keep the temperature below -30°C.

Effects of the Invention As described above, according to the present invention, there is an excellent effect that double-sided vapor deposition can be realized over a long length without thermal damage even if the polymer film is made thin.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of an example of a magnetic recording medium obtained by the present invention, and FIG. 2 is an internal configuration diagram of a vapor deposition apparatus used in carrying out the present invention. 1... Polymer film, 2, 3... Vapor deposited film, 8... First cooling can, 11...
...Second cooling canister, 12...Mounting ring.

Claims (1)

[Claims] Magnetic recording characterized in that after a vapor-deposited film is formed on one side of a polymer film, when it is vapor-deposited on the other side, the film is vapor-deposited along a rotating support whose hardness is lower than that of the vapor-deposited film in contact with the rotating support. Method of manufacturing media.