JPH046624A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the adhesiveness between the surface of a protective film and a lubricant with a simple equipment by subjecting the protective film to any of a ultrasonic (UV) treatment, UV+ozone treatment and UV+ozone+ water treatment. CONSTITUTION:The protective film is formed on a base material having a magnetic material and the surface of this protective film is treated with any of UV, UV+ozone or UV+ozone+water, by which the surface is polarized and the adhesiveness to the lubricant of a fluorine system is improved. The UV treatment refers to irradiation with UV light of 150 to 400nm wavelength and the UV+ozone treatment refers to a method of spraying ozone simultaneous ly with the above-mentioned treatment. The UV+ozone+water treatment refers to the spraying of steam in addition to the UV+ozone treatment. The associa tion or chemical bond of the polar groups of the lubricant with the polar groups on the surface of the protective film is executed in this way, by which the adhesiveness of the lubricant onto the protective film is improved. The equip ment is thereby simplified and the conduction of the operations in a short period of time is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing a magnetic recording medium used for recording information in electronic devices and the like.

[Prior Art] In magnetic disks and magnetic tapes, recording is made possible by coating a magnetic material on a base material. In order to protect recorded information from external shocks, it is necessary to provide a protective film on the magnetic material. However, since stopping and sliding are repeated during recording and reproduction, friction occurs between the magnetic head and the protective film in the dark, resulting in wear of the protective film. To prevent this, lubricant is applied onto the protective film, but because the adhesion between the protective film and the lubricant is weak, the lubricant may peel off or repel due to repeated operations. A new problem arose. As a solution to this problem, the surface of the protective film is polarized by subjecting it to surface treatment. For example, JP-A-62-15052
6, the carbon protective film is subjected to plasma treatment,
Furthermore, in JP-A-63-2117, the surface of the vapor deposited layer is subjected to one of plasma treatment, glow treatment, and corona discharge treatment.

[Problems to be Solved by the Invention] These conventional methods use a vacuum device or a high voltage, so the voltage requirement is large, the work is tedious, and the work time is lengthened. In addition, the adhesion of the lubricant was also unsatisfactory.

An object of the present invention is to obtain a magnetic recording medium that has simple equipment, can perform zero operation in a short time, and has excellent lubricant adhesion.

[Means for Solving the Problems] The present invention forms a protective film mainly composed of carbon-based, hydrocarbon-based, or metal carbides, nitrides, and oxides on a base material having a magnetic material, The surface of the protective film is exposed to UV light.
This is a method for manufacturing a magnetic recording medium in which the surface is polarized by treatment with either +ozone or UV+ozone to improve adhesion with a fluorine-based lubricant.

Here, UVlA11 means a wavelength of 150 nm to 400 nm.
A low-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, etc. is used as the light source, and the illumination intensity is 30 aw/cd or more, preferably 10 C) + W/aJ.
The above shall apply. Moreover, UVl-ozone treatment is a method of spraying ozone at the same time as the above treatment. Ozone is
Generated by an ozonizer, the flow rate is 1-10 Q/
win, the concentration is 10 g/rn' or more, preferably 100 g/m' or more. UV + ozone + water treatment means spraying water vapor in addition to UV + ozone treatment. For example, water vapor.

There are two methods: passing ozone gas through a bubbler filled with water and spraying it together with ozone, and spraying it directly. The treatment effect is significantly more efficient in UV treatment than in conventional plasma treatment.

For more efficient treatment than UV treatment, tJV+ozone treatment is better, and for more efficient treatment than UV treatment, UV+ozone+water treatment is effective.

In addition to the method of performing the above-mentioned processing on one side, it is also possible to perform the above processing on both sides of the substrate at the same time in the case of a magnetic disk or the like.

In the present invention, the base material includes a polymer film such as polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyamideimide, polyesterimide, polyimide, etc.

Hard materials such as AQ and AQ alloy, mylar, ceramics, and glass are used on top of these.

Co-Ni-Zr, Co-Ni-Ti, Co-
Ni-Pt, Co-Ni-Cr, Go-Ni
-Mo, Co-N1-AQl Co-Cr-Ti,
Co-Cr-Pt, Go-Cr, Co-Al1
, Co-Fe, Co-Ta, Co
A magnetic film is formed by applying a magnetic material containing -Re, Co-W, Co-Ru, Go-Mo, etc. as components.

Furthermore, a protective film is applied on the magnetic film by sputtering, vacuum evaporation, or
It is formed by an ion blasting method, a CVD method, or the like.

Protective films include carbon-based, hydrocarbon-based, metal carbides, nitrides, and oxides, and carbon-based materials include graphite-like C,
Diamond-like C1 hydrocarbon systems include hydrogen-containing amorphous C1 metal carbides with B, C, WC, WNiC1 metal nitrides with (TiV)N, (TiNb)N, and (TiT).
a) N, (ZrV)N, (ZrTa)N, (ZrW)N
, (WNb)N, (WCr)N, (NbCr)N, Nb
N, AQ for metal oxides, 03+ (ZrAn)O
There are l(ZrNb)O, ZrY-AQ○, etc.

A fluorine-based lubricant having a concentration of 0.1 to 1% is applied onto the protective film treated as described above by dip coating, spin cord coating, spray coating, or the like. As the fluorine-based lubricant, a compound having a fluorocarbon skeleton in its molecular skeleton can be used. For example, perfluorocarboxylic acid ester, perfluorothiol carboxylic acid ester, perfluorodicarboxylic acid ester, perfluorocarboxylic acid perfluoroalkyl ester, perfluorobenzoic acid ester, carboxylic acid perfluoroalkyl ester,
dicarboxylic acid perfluoroalkyl ester, carboxylic acid perfluoroalkoxyalkyl ester, perfluorocarboxylic acid amide, perfluoropolyether,
Examples include perfluoropolyether carboxylic acid, perfluoropolyether alcohol, and perfluoropolyether ester.

[Effect] By performing the above treatment, ketone groups (=C=O), hydroxyl groups (-OH), and acids (-C○○H) are formed on the surface of the protective film.
, peroxide (EC○○H) and other polar groups are efficiently formed. This allows the polar groups of the lubricant to associate or chemically bond with the polar groups on the surface of the protective film, thereby improving the adhesion of the lubricant onto the protective film.

[Examples] Hereinafter, specific examples of the present invention will be described in detail.

Example 1 N1-P, Cr on a φ130m AQ substrate.

Go-Ni-Zr sequentially 10us, 420nm, 50n
m was formed and placed in a vacuum chamber. Inside the vacuum chamber 10-@To
After creating a vacuum level of rr or higher, argon gas (gas pressure:
A 45n carbon-based protective film was formed by sputtering using graphite as a target.Next, as a process to polarize the protective film, wavelengths of 185nm and 254n@, illumination intensity were 100mV
/ff1 or higher UV light was irradiated for a predetermined period of time (UV treatment). Also, at the same time as the above processing, a flow rate of 3
Q/win, the same treatment was performed for spraying ozone at a concentration of 100 g/m' or more (UV+ozone treatment). Ozone is produced using an ozonizer (raw material: oxygen gas, fi pressure =
150V, current: 5A). In UV + ozone treatment, ozone is generated with an ozonizer and then passed through pure water in a glass container.

A treatment was also performed by spraying the surface of the protective film (UV + ozone + water treatment).

On the other hand, as a comparative example of the process of polarizing the protective film, 10-"
A substrate with a protective film formed thereon is placed in a tank maintained at a vacuum level of Torr or higher, and oxygen gas (gas pressure: 200 mTo
r r) was introduced, and plasma treatment was performed with a power of 0.15 W/d.

Regarding the treatment method described above, when the contact angle on the surface of the protective film immediately after treatment is measured using water, it is as shown in FIG. 1. In the conventional method of plasma treatment, the contact angle is 10
UV treatment, UV
With +ozone treatment and UV + ozone + water treatment, the temperature drops to around 5 degrees.

In addition, it took about 2 minutes to reduce the contact angle of the protective film to 10 degrees or less using the conventional plasma treatment method, but it took 30 seconds with the I;v treatment, UV + ozone treatment, and UV + ozone hand washing treatment of the present invention. I can do two things with a certain degree.

Example 2 Various treatments similar to those shown in Example 1 were applied to the surface of the protective film (
Examples: UV treatment, UV + ozone treatment, UV + ozone +
A substrate subjected to water treatment (comparative example: plasma treatment) was immediately immersed in a lubricant with a concentration of 0.3% after the treatment. After soaking for 1 minute, it was soaked in Freon 113 for 3 minutes to remove excess lubricant. Lubricants include F (CF-CF, -0), -C2F4CH, -0HC
F, (molecular tray: approximately 6000) was used. When the lubricant film thickness was measured using FT-IR on a substrate coated with lubricant, it was as shown in Figure 2.The lubricant film thickness was 1.5 to 2 nm using conventional plasma processing methods, but the lubricant film thickness was measured using FT-IR. The wavelength can be reduced to 3 to 8 nm by applying the UV treatment, UV + ozone treatment, or UV + ozone + water treatment of the present invention.

Example 3 In the case where the protective film is carbon-based, tungsten-carbon-based, or titanium-nitrogen-based, and the lubricant is IF (CF-CF, -〇). -〇2F4CH2-
○HCF□ (Molecular weight: approx. 6000) II
F (CF-CF, -0), -02F, C○0HCF
3 (Molecular weight: approx. 6000) III C, F2
O-(C,F,O), C,F, -C○○C,H.

(molecular weight: approximately 4000), the film thickness was measured for each treatment method in each combination. The protective film was formed in the same manner as in Example 1 for the carbon-based protective film, and for the tungsten-carbon-based dititanium-titanium-based protective film.

An AQ substrate on which a magnetic film was formed in the same manner as in Example 1 was placed in a vacuum layer, and a mixture of argon gas and nitrogen gas at a mixing ratio of 1:1 was placed in a tank maintained at a vacuum level of 10-' Torr or higher. Introduce mixed gas (gas pressure: 10 mTorr) and turn W/ to 32.
A protective film of 45n+s was formed by sputtering with a power of rrl' applied. Each of these substrates was subjected to UV treatment, UV+ ozone treatment, and Uv+ treatment similar to the treatment shown in Example 1.
Ozone + water treatment and plasma treatment were performed for 5 minutes, and lubricant 1. II and ■ were applied and the film thickness was measured. As shown in Table 1, the UV according to the present invention
The protective film subjected to the treatment, UV + ozone treatment, UV + ozone + water treatment has a significantly larger lubricant adhesion film thickness than the protective film subjected to the plasma treatment of the comparative example. It should be noted that almost no changes were observed due to differences in the components of the protective film or the components of the lubricant.

Regarding the combination of carbon-based protective film and lubricant I, C8
When the C3S-tangential force was calculated when the S (Contact-8tart-8top) test was performed IOK times,
In contrast to the plasma treatment of the comparative example, which was 5 to 6 gf,
UV treatment of the present invention, UV + ozone treatment, UV + ozone +
Water treatment resulted in 2-4 gf. From the above results,
It is clear that the treatment method of the present invention improves the adhesion between the protective film and the lubricant.

Table 1 [Effects of the Invention] According to the present invention, unit: By subjecting the protective film of a magnetic recording medium to UV treatment, UV + ozone treatment, or UV + ozone + water treatment, a simple method that does not use a vacuum system can be achieved. The equipment can significantly improve the adhesion between the protective film surface and the lubricant. This facilitates lubrication between the magnetic recording medium and the magnetic head during actual operation of the magnetic recording medium, thereby achieving improved reliability and longer life of the magnetic recording medium.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between treatment time and water contact angle for each treatment method, and Figure 2 is a graph showing the relationship between treatment time and lubricant film thickness for each treatment method. . Explanation of symbols 1...UV treatment, 2...UV+ozone treatment, 3...
・UV + ozone + water treatment, 4 river plasma treatment. Processing time (n+in)

Claims (1)

[Claims] 1. A magnetic film and a protective film are provided on a base material, and the surface of the protective film is subjected to one of ultraviolet (hereinafter referred to as UV) treatment, UV + ozone treatment, UV + ozone + water treatment. A method for producing a magnetic recording medium in which a fluorine-based lubricant is applied after applying a fluorine-based lubricant. 2. The method of manufacturing a magnetic recording medium according to claim 1, wherein the protective film is mainly composed of a carbon-based material or a hydrocarbon-based material. 3. The method of manufacturing a magnetic recording medium according to claim 1, wherein the protective film contains a metal carbide, nitride, or oxide as a main component.