JPS63121119A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve durability and weatherability by disposing a lubricating agent by a soln. coating method on a thin ferromagnetic metallic film disposed on a high-polymer film, then subjecting the coating to an ozone treatment. CONSTITUTION:The thin ferromagnetic metallic film is disposed on the high- polymer film which is a substrate 1 to be treated and the lubricating agent is disposed by the soln. coating method thereon. The soln. coating method is executed by dissolving the lubricating agent into a solvent, coating the soln. thereof by a reverse roll coater, bar coater, etc. on the film and drying the coating. An electron beam is accelerated from an electron beam generator 7 in an ozone treatment vessel 6 and the ozone is taken out of titanium foil or the like into the atm. and is produced from the oxygen in the air, by which the coating is treated. The reaction between the lubricating agent and the thin ferromagnetic metallic film progresses so that said agent and film stick strongly. The part in the thin ferromagnetic metallic film where the degree of oxidation is weak is reinforced by such adhesion plus the oxidation effect of the ozone. The use of the medium at and under the high temp. and high humidity is thereby permitted and the preservable characteristic is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a magnetic recording medium having a magnetic recording layer made of a ferromagnetic metal thin film suitable for high-density magnetic recording.

Conventional technology A magnetic recording medium whose magnetic recording layer is a ferromagnetic metal thin film, which is suitable for high-density magnetic recording, has a magnetic recording layer formed by electron beam evaporation,
After forming by sputtering method or the like, a top coat layer is applied by solution coating method, vacuum evaporation method, etc. and then processed to a predetermined size [for example, IEICE Magnetic Recording Study Group materials, MRE]1. -2 (1981), JP-A-57
-189331.

JP-A-57-15i0136, JP-A-57-1799
No. 48, JP-A-61-126627.

JP-A-61-11930, JP-A-61-151835
No. 61-151837].

The importance of the top coat layer has recently been recognized, and many proposals regarding materials have been made.

In particular, for the purpose of improving durability, diamond-like carbon film,
Plasma polymerized membrane, 5tO2 sputtered membrane.

A laminated type of M o S 2 sputter film and lubricant is attracting attention.

Coating with a lubricant is often done by a wet solution coating method, which is superior in mass production than an organic vapor deposition method.This method requires optimization of the combination of lubricant and solvent and drying conditions. It's getting older.

Problems to be Solved by the Invention However, with the above-mentioned configuration, when used repeatedly in a high temperature and humid environment, the lubricant decreases and there is no sufficient lubricating action, resulting in increased noise and poor still characteristics. The present invention has been made in view of the above-mentioned circumstances, and has been developed in view of the above circumstances. The present invention provides a manufacturing method suitable for obtaining a magnetic recording medium with improved weather resistance.

Means for Solving the Problems In order to solve the above-mentioned problems, the method for producing a magnetic recording medium of the present invention involves distributing a lubricant on a ferromagnetic metal thin film disposed on a polymer film by a solution coating method. After that, it is treated with ozone.

Function: The method for producing a magnetic recording medium of the present invention has the above-described structure, so that the reaction between the lubricant and the ferromagnetic metal thin film progresses and they adhere firmly, and the oxidation effect of ozone causes the ferromagnetic metal thin film to oxidize. Since it reinforces the weak areas, the weather resistance is also improved, and since this effect is thought to be accompanied by reaction adhesion of the lubricant, the degree of improvement is also large.

EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings. The figure shows an ozone treatment apparatus used to carry out the present invention. In the figure, 1 is a processing substrate, which has a ferromagnetic metal thin film arranged on a polymer film, and a lubricant applied thereon by a solution coating method.

Polyethylene terephthalate,
Polyphenylene sulfide, polyimide.

Polycarbonate or the like is suitable, and the ferromagnetic metal film is Co-Or of about O*05 to O-2 μtEi formed by electron beam evaporation, sputtering, or the like.

Go-Ti, C6-Mo, Co-0, Co
-Ni, Go-Fe.

High coercive force films such as Co-Cr-Nb and Go-Ni-0 are used. The solution application method involves dissolving the lubricant in a solvent.
It is applied and dried using a sole reverse roll coater, bar coater, etc., and the lubricant may be a fatty acid, a fatty acid ester, a fatty acid amide, a fluorine compound, a silicone oil 1, etc. alone or in a mixture, and there is no particular restriction.

2 is a feed shaft, 3 is a winding shaft, 4 is a coating head schematically shown, and 6 is a drying oven, which is suitable for hot air drying. 6 is an ozone treatment tank, and 7 is an electron beam generator. 8 is a rotating roller, and the ozone generation method accelerates an electron beam and extracts it from a titanium foil into the atmosphere.
There is no difference depending on the method, not only the method of producing ozone from oxygen in the air, but also the method of producing ozone by atmospheric discharge.

However, it is of course possible to add the effect of electron beam irradiation depending on the conditions, but ozone has a great effect.

Examples will be described in more detail. 2 x 1 on polyethylene terephthalate film with a thickness of 12 μm
Go-Ni (Ni
, 20 wt%) was obliquely deposited at a minimum incident angle of 36 degrees, and 0.
A Co-Ni-0 film with a coercivity of 16 pm and a coercive force of 1 ooo (Os) was placed, and stearic acid dissolved in toluene was dried and
q/J and ozone treatment was prepared as tape A, and tape B was prepared without ozone treatment. Ozone treatment is performed at 200K using 15μm thick titanium foil.
The electron beam accelerated to V is 0.04mA/c1! It was taken out and exposed to the generated ozone atmosphere at a distance of 50 m/cm. The ozone concentration was 6000 ppm.

Further, by high frequency sputtering method, 0.16. Co in μm
-Or (Or 20 , 6 wt%) perpendicularly magnetized film [perpendicular coercive force 590 (Os)] was disposed, and methyl gutsselate was dissolved in methyl isobutyl ketone or 6 wt% when dried.
The tape was coated and dried to give q/WI2 and ozone treated under the same conditions as Tape A, which was designated as Tape C, and the untreated product was designated as Tape D.

Tapes A to D were repeatedly recorded and played back on a commercially available 8 mm video tape. The number of passes in which disturbances were observed on the screen due to increased jitter in an environment of 46°Cay%RH was 68 passes for Tape B and 73 passes for Tape D, but in the example, 60 passes were repeated. was not recognized at all.

In addition, dropout was measured after storage at 60°C and 80% RH for 4 months, and when expressed as a magnification normalized to the initial value, tape A was 2.2 times, tape B was 16.9 times, and tape C was 1. 8 times, tape D was 24.5 times.

In addition, the tape was run 50 times at 50°C and %RH, and the C/N and still characteristics were compared with all initial values at room temperature and humidity.

C/N is the signal-to-noise ratio of the luminance signal, and the head is of a metal-in-gap type. The still characteristics are that the playback output is 3 (d
B) This is a comparison based on the time of decline.

Tape A, B, C, D (7) C/N change is 0
(dB).

-3.5 (dB), o (dB), -4-7 (dB), and still characteristics were 98 minutes, 17 minutes, 95 minutes, and 21 minutes.

Effects of the Invention As described above, the present invention has excellent effects such as being able to produce large quantities of magnetic recording media that can be used at high temperatures and high humidity and have improved storage characteristics.

[Brief explanation of the drawing]

The figure is a schematic configuration diagram of an ozone treatment apparatus used in an example of the present invention. 1... Processing substrate, 4... Coating head, 6... Drying oven, 6... Ozone treatment tank.

Claims (1)

[Claims] 1. A method for manufacturing a magnetic recording medium, which comprises disposing a lubricant on a ferromagnetic metal film disposed on a polymer film by a solution coating method, and then subjecting the film to ozone treatment.