JPS59175031A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium having improved running property, still characteristic, corrosion resistance and durability in particular by depositing continuously by evaporation a thin ferromagnetic film on a substrate then taking up the substrate in a vapor atmosphere of an org. material having lubricating capacity and forming org. material layers on both surfaces of the substrate. CONSTITUTION:A ferromagnetic metal 6 of Co, etc. is deposited by evaporation on a substrate 1 of polyethylene terephthalate, etc. to form a thin ferromagnetic film. A higher fatty acid ester or higher fatty acid and its amide, etc. or a mixture composed thereof used as an evaporating source 15 in a plate 9 having a jacket construction enclosing concentrically a take-up shaft 4 and the substrate 1 is taken up in the vapor atmosphere of such org. material. The org. material layers are thus formed on both surfaces of the substrate 1, by which the lubricating layers and protective layers stuck more securely on the substrate than by the conventional coating method are formed, and the magnetic recording medium having improved lubricity and corrosion resistance of the magnetic film and having excellent durability is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a thin metal film type magnetic recording medium having excellent short wavelength recording characteristics.

Conventional configurations and their problems Traditionally, magnetic recording media have been made of Co-doped γ-Fe2O3 or CrO□ on a polymer substrate or aluminum substrate.
So-called coating type materials, in which powdered magnetic materials such as oxide magnetic powders such as oxide magnetic powders or ferromagnetic alloy powders are dispersed in organic binders such as polyurethane resins, coated and dried, are widely used in practical use. There is.

However, in recent years there has been a strong demand for recording density, and the conventional coating type has reached its limit in improving recording density.As a new medium, metal thin film magnetic recording media with excellent short wavelength recording characteristics are attracting attention and are being put into practical use. Efforts toward this goal have been actively carried out in various fields.

Although currently available metal thin film magnetic recording media have excellent initial characteristics, they are insufficiently durable to maintain these characteristics, and are difficult to put into practical use. Technologies that can produce improved media in large quantities are becoming important. The manufacturing method currently disclosed for paralysis is the closest to practical use.
It is said that the method that is said to be a method of depositing on a polymer substrate, rolling it up, taking it out into the atmosphere, applying a lubricant or rust preventive agent to the surface of the non-adhesive layer, and drying it.
The performance of the obtained medium was insufficient, and when considering improvement in terms of practical durability, it had the disadvantage of a decrease in C/1'J at short wavelengths.

OBJECT OF THE INVENTION The present invention provides a manufacturing method that can produce a large amount of media with significantly improved practical durability, particularly corrosion resistance durability in running and still characteristics, without deteriorating the CA characteristics in the short wavelength range. purpose.

Structure of the Invention The manufacturing method of the present invention includes continuously depositing a ferromagnetic thin film on at least one side of a substrate, and rolling up the substrate in an organic substance vapor atmosphere. It is characterized by forming organic layers on both sides of the substrate.

The substrate used in the present invention is a polymer substrate such as polyethylene terephthalate, poly1mide, polyimide, polyvinyl chloride, polyethylene naphthalate, polycarbonate, cellulose triacetate, etc., or if necessary, vapor deposition or plating on the above polymer substrate. In the present invention, evaporation refers to evaporation using an electron beam. It refers to thin film forming means such as vapor deposition, induction heating vapor deposition, sputtering, ion blating, and four-field vapor deposition.

The equipment for performing vapor deposition and atmosphere winding described below is as follows:
A semi-continuous winding vapor deposition machine, which is already used in the capacitor and decoration fields, is used as a basis, modified as appropriate for carrying out the present invention.

The ferromagnetic n film used in the present invention is C().

Fe, Ni, or various alloys based on these,
For example, Co-Ni, Co-Fe, Co-(:r,
Co-(u, Co-Pt* Co-Gd.

Examples include Co-5n, Co→↑-Cr, and partially oxidized thin films thereof, and include both in-plane magnetized films and perpendicular magnetized films classified by oxidation direction.

One way to maintain the winding portion at the saturated vapor pressure of organic matter is to place a hot plate around the winding shaft so as to maintain it at a constant temperature, and also to keep the steam source at a constant temperature. Can be mentioned. There may be a single vapor source or a plurality of vapor sources. The winding atmosphere may be a single organic substance or a mixture of organic substances. The organic substance used is selected from fatty acids, fatty acid amides, paraffinic hydrocarbons, fatty acid esters, fatty acid alcohols, and the like.

DESCRIPTION OF EMBODIMENTS The manufacturing method of the present invention will be described below based on a specific embodiment. In addition, in the following examples, 10 indicates pre-treatment such as blowing treatment as necessary, and C indicates elements used in normal rolling vapor deposition.Those not directly related to the detailed description of the present invention are omitted. do.

The drawing shows a configuration diagram of an embodiment of a magnetic recording medium manufacturing apparatus that implements the manufacturing method of the present invention.

The substrate (υ) moves along the circumferential side of the cylindrical cooling can (2), and moves from the feeding shaft (3) to the winding shaft (4).
It is configured to be rewound. One side of the substrate (1) is placed along the circumferential side of the cooling can (2), and the ferromagnetic material (6) charged in the evaporation source container (5) is placed along the circumferential side of the cooling can (2).
) is exposed to a part of the vapor flow (7) obtained by heating the Cf:J, and a ferromagnetic thin film is formed in the four exposed parts. (8) is a bean that limits the angle of incidence by oblique evaporation.

In addition, when obtaining a perpendicular magnetic sublayer as a four-layer ferromagnetic film by sputtering or by electron beam evaporation, another ingenuity 5 is required.

The polymer substrate on which the ferromagnetic thin film is formed is wound in an organic substance atmosphere during winding as follows. A plate (9) is arranged to surround the winding shaft (4) substantially concentrically, and a temperature-controlled heating medium is flowed inside the plate (9) to maintain the surface temperature of the plate (9) at a constant temperature. At the same time, the winding atmosphere Jt (1
) is configured to maintain a constant partial pressure of organic matter.

These systems are arranged inside a vacuum chamber OcI, and the vacuum chamber αQ is divided into two chambers (1) (1) by a partition (to), each of which is evacuated by a vacuum exhaust system θρ (to). There is. 0<
is a rotating roller.

Next, a more detailed explanation will be given based on an experimental example.

Example polyethylene terephthalate film (thickness 10.5μ
An alloy of 80% Co, N and 20% i was deposited using an electron beam on the surface (width 50 ann) using an electron beam. Cooling Can (2)
) has a diameter of 100 an, the surface temperature of the cooling can (2) is 5℃, and the degree of vacuum is 8X10-Il'Tor.
The maximum partial pressure at r is general element and its partial pressure value is 2.5 x 10
' Torr. The angle of incidence was 48° or more, and the average deposition rate was 2200/J'ac! It is. 0.181
After completing the formation of the t- Co--Ni O film and after 1.8 SeC, the substrate (1) was wound up in a winding atmosphere (1) of 0.18 Torr of butyl steering acid. The diameter of the winding core was 16.5 an, and the winding tension was 8.8 kg. After the completion of the total deposition length of 2000 fllX+), the source temperature of butyl stearate and the temperature of the heating medium of the jacket plate were lowered, and after one hour, it was taken out into the atmosphere and 8〕m+
A magnetic tape was obtained by cutting it into widths.

EXAMPLE An alloy of 80% C0 and 2G% Ni was deposited by electron beam on a polyethylene terephthalate film (thickness g pm width 50 cm). 0, 18 p under the same conditions as [Experiment-1]
Methyl lignocerate (18 Torr winding atmosphere (f
), the substrate (1) was wound up. The subsequent conditions until tape formation were the same as in [Experimental Example-1].

Example polyethylene terephthalate (thickness 8.6 μm 9 width 50
an) Electron beam evaporation of an alloy of 80% Co and 20% Ni. 018 μm under the same conditions as [Experimental Example-1]
After the completion of the Co-N i () film formation, after 1.84 EC, the substrate (1 ). The other conditions until tape formation thereafter were the same as in [Experimental Example-1].

Example polyethylene terephthalate film CM size 8.5pf
An alloy of 80% Co and 20% Ni was deposited by electron beam evaporation on the substrate (width 50 ann). 0 under the same conditions as [Experiment Example-1]
．． 1.8 seconds after completion of the formation of the 18 μm co-Ni-0 film, the substrate (1) was wound up in a winding atmosphere (1) of 0.9 Torr of myristic acid. The conditions up to tape formation were the same as in [Experimental Example-1].

Example polyethylene naphthalate film (thickness 5 μm width 50
01) An alloy of 78% Co and 22% Cr was deposited to a thickness of 062 μm by high frequency magnetobutron sputtering.

The distance between the cooling can (1 m diameter, surface temperature 86 °C) and the sputter cathode was 9.6 an, and argon was
The maximum partial pressure was 4.5 x 10" Torr. 12.6'sec after the completion of the formation of the Cock perpendicular magnetization film.
Afterwards, a winding atmosphere of 0.07 Torr of stearic acid (1
), the substrate (1) was wound up. Winding core diameter is 16.5
cfl and the winding tension was 2.4 kg. Total length 1000
After the vapor deposition of m was completed, it was cooled, and after 1 hour, it was taken out into the atmosphere and cut into a width of 8+ am to obtain a magnetic tape.

[Comparative Example-1] After forming a Co-Ni-0 film similar to [Experimental Example-1], it was taken out into the atmosphere after 1 hour, and a coating solution containing 150 parts of n-hexane per 1 part by weight of butyl stearate was added. Coating was performed by reverse roll to obtain a 5IEI1 width tape.

[Comparative Example-2] The other conditions were the same as [Experimental Example-2], except that winding was not carried out in a methyl lignocerate atmosphere. Coating liquid D was applied to the substrate to obtain a tape.

[Comparative Example-8] A substrate under the same conditions as in [Experimental Example-8] except that it was not wound in an organic atmosphere was taken out into the atmosphere, and an O coating liquid was applied thereto to obtain a tape.

[Comparative example-4J A tape was obtained by coating the coating liquid.

[Comparative Example 6] A substrate under the same conditions as in [Experimental Example 6] except that it was wound in an organic atmosphere was taken out into the atmosphere, and a stearic acid coating solution was applied to obtain a tape.

As a method for comprehensively evaluating the durability of the tapes obtained in the above experimental examples and comparative examples, tests were conducted under the following conditions, and the results are shown in the table below. The conditions were a commercially available VHS deck [Matsushita Electric, Matsuku Road 88 (N
An 8I width deck with a running system equivalent to that of V-8800) J was manufactured for testing, and evaluated by repeatedly running the tape over a tape length of 50 m and measuring the still characteristics. The environment evaluated was ・80℃190~1%R)l, and a certain 1
゜However, corrosion resistance evaluation environment j, i55゜”C,'lO+
・%, RH,...; 1・How much percent did the initial flux amount of the tape decrease when it was left for i months?
teV, 6. A comparison was made using the average value measured with a vibrating sample magnetometer.Also, the initial output in a normal environment was set to 0d13, the still was played for 10 minutes, and the output at this time was compared. jko.

Table 2 From these results, the superiority of the performance of the medium obtained by the manufacturing method of the present invention is clear.

This is due to the following reasons.

After forming a ferromagnetic thin film and before exposing it to the atmosphere, the surface is placed in an active state in an atmosphere of organic substances that serve as rust preventives, lubricants, etc., so that the organic substances are firmly attached to the ferromagnetic thin film. At the same time, the organic substance adheres to the surface of the substrate opposite to the surface with the ferromagnetic layer because it is rolled up in an atmosphere 8 times. The transfer serves as a source of minute amounts of lubricants, rust preventives, etc. to the surface, further improving durability.

Compared to simply applying with a wet method, it not only attacks fine details with steam, but also has a sintering effect, so it has a greater protective effect.

In the manufacturing apparatus of the above embodiment, the winding atmosphere 1) is exhausted by a common exhaust system with the chamber (1) of the vacuum chamber 01, but it is also possible to independently exhaust the winding atmosphere (1). .

In the above example, the ferromagnetic thin film was deposited only on one side of the substrate, but this was done by rolling up the substrate with the ferromagnetic thin film deposited on both sides of the substrate in a saturated vapor atmosphere of organic material. Organic layers can also be formed on both sides of the substrate.

According to the method for manufacturing a magnetic recording medium as described in the detailed description of the invention, the substrate is rolled up in an organic vapor atmosphere to form an organic layer on both sides of the substrate on which the ferromagnetic thin film is deposited. effect) can be obtained.

9 Unlike conventional coating, a small amount of lubricant, rust preventive agent, etc. is sufficient to fulfill its role, and there is no inconvenience such as deposition on the head surface and increased spacing loss, and high C+ is maintained as is. Hold and pull.

・Short wavelength records can be achieved using only a dry method that does not require explosion-proofing or pollution countermeasures.
ζζ Useful metal thin film magnetic recording media can be produced in large quantities.

It has become possible to solve the problems of metal thin film magnetic recording media, such as durability and corrosion resistance, on a mass production scale.
It is possible to supply a large amount of magnetic recording media necessary for high-density magnetic recording such as ultra-small VTRs.

[Brief explanation of drawings]

The drawing is a block diagram of the main parts of a manufacturing apparatus according to a specific embodiment of the manufacturing method of the present invention. (1)... Board, (2)... Cooling can, (
6)...Ferromagnetic material, (9)...Jacket plate, (It)...Vacuum chamber, ni)...Organic vapor source,
(1)... Winding atmosphere agent Yoshihiro Fumoto 13

Claims (1)

[Claims] 1. A ferromagnetic thin film is continuously deposited on at least one side of the substrate, and this substrate is rolled up in an organic material vapor atmosphere to form an organic layer on both sides of the substrate where the ferromagnetic thin film has been vaporized. A method for manufacturing a magnetic recording medium.