JPH09251636A - Magnetic recording media - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic tape having appropriate toughness and improved durability. SOLUTION: This recording medium has a substrate 1, a magnetic film 2 and a protective film 4. The protective film 4 has constituent C atoms and constituent H atoms and its Raman spectrum shows a peak having an intensity of JG at a wave number in the region of 1,550±50cm<-1> , also another peak having an intensity of ICH at a wave number in the region of 2,900±200cm<-1> and an IGH/IG value within the range of 0.1 to 1.4.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a magnetic recording medium.

[0002]

Due to the demand for high-density recording, a magnetic layer provided on a support is not a coating type using a binder resin, but is a metal tape that does not use a binder resin. Thin film types have been proposed. That is, a magnetic tape in which a magnetic layer is formed by wet plating means such as electroless plating or dry plating means such as vacuum evaporation, sputtering or ion plating has been proposed. This kind of magnetic tape has a high filling density of a magnetic material and is suitable for high-density recording.

In order to protect the metal magnetic film of the magnetic tape, it has been proposed to provide various protective films on the surface. For example, a diamond-like carbon film is one of these proposals. In addition, the diamond-like carbon film is formed, for example, by a hot filament CVD device, a photo CVD device,
CVD of RF plasma CVD equipment, microwave plasma CVD equipment, ECR microwave plasma CVD equipment, etc.
(Chemical vapor deposition) provided by a device.

However, it has been found that the conventional diamond-like carbon film is not sufficiently satisfactory. In particular, in the case of a magnetic disk using a flexible plastic material, not a magnetic disk using a hard disk as a support, particularly in the case of a magnetic tape used in a helical scan type recording / reproducing apparatus,
It has been found that the flexibility of the magnetic head is not good and the durability is poor.

Therefore, it is an object of the present invention to provide a magnetic tape having appropriate toughness and improved durability.

[0006]

The object of the present invention is to provide a magnetic recording medium having a support, a magnetic film and a protective film, wherein the protective film has a C component and an H component, and , Raman spectrum, 1550 ±
The intensity has a peak of I _{G in} the region of 50 cm ⁻¹ and the intensity has a peak of I _{CH in} the region of 2900 ± 200 cm ⁻¹ , and I _CH / I _G is 0.1 to 1.4. It is solved by a magnetic recording medium characterized in that the value is within the range.

In particular, in a magnetic recording medium having a support, a magnetic film, and a protective film, the protective film is a carbon-based film in which hydrocarbon is present, and has a Raman spectrum of 1550 ± 50 cm ⁻¹ . The intensity has a peak of I _G in the region, and the intensity has a peak of I _{CH in} the region of 2900 ± 200 cm ⁻¹ , and I _CH / I _G has a value of 0.
This is solved by a magnetic recording medium having a value within the range of 1 to 1.4.

Furthermore, in a magnetic recording medium having a support, a magnetic film and a protective film, the protective film is a diamond-like carbon-based film in which hydrocarbon is present, and
In Raman spectrum, 1550 ± 50 cm ^-1
Has a peak of I _G due to the diamond-like carbon in the region of 2900 ± 200 cm ⁻¹
In the region of the above, the intensity due to the C—H bond of the hydrocarbon contained in the diamond-like carbon film has a peak of I _CH , and the I _CH / I _G is 0.1 to 1.4. This is solved by a magnetic recording medium characterized by being a value within the range.

In this magnetic recording medium, 0.4 ≦
Those with I _CH / I _G ≦ 1.3 are preferred. That is,
In the magnetic recording medium having the protective film configured as described above, hydrocarbon (C—H bond) is appropriately present in the protective film,
Therefore, the protective film itself has an appropriate toughness, and as a result, the durability is improved.

The features of the present invention are further exerted in a magnetic tape in which a magnetic film is provided on a flexible support, a protective film is provided on the magnetic film, and a lubricant is provided on the protective film. It

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a support, a magnetic film and a protective film.
In the magnetic recording medium having a film, the protective film is C
Having Raman and H components, and Raman spectroscopy
1550 ± 50 cm in the spectrum^-1Strong in the area of
Degree I_GWith a peak of 2900 ± 200c
m^-1Intensity is in the region of_CHHaving a peak of
_CH/ I _GIs a value within the range of 0.1 to 1.4. Especially,
In a magnetic recording medium having a support, a magnetic film and a protective film
The protective film is a carbon-based film containing hydrocarbons.
And in the Raman spectrum, 1550 ±
50cm^-1Intensity is in the region of_GWith the peak of
2900 ± 200 cm^-1Intensity is in the region of_CHThe pea
The above I_CH/ I_GIs in the range of 0.1 to 1.4
This is the value within the range. And, in particular, the protective film is
It is a diamond-like carbon-based film in which the element exists,
And, in the Raman spectrum, 1550 ± 50
cm^-1Due to diamond-like carbon in the area of
Intensity is I_GWith a peak of 2900 ± 200
cm^-1In the diamond-like carbon film
The strength due to the C—H bond of the hydrocarbon contained in_CH
Having a peak of_CH/ I_GIs 0.1-1.
It is a value within the range of 4. In particular 0.4 ≦ I_CH/ I_G≤
1.3.

A method of obtaining the peak intensities I _G and I _{CH in} the present invention will be briefly described. As a measuring device, a triple spectrometer manufactured by Spex was used. The light source is an Ar laser with a 300 mW output and a wavelength of 488 nm. Then, the sample S is irradiated with an Ar laser of 488 nm at a low angle of 5 °, and the scattered light from the sample S is spectroscopically measured by the measuring instrument (triple spectrometer) with respect to the irradiation light and the scattering light in the 90 ° direction. To do. The measurement time (integrated time) is 10 minutes, at least three points are measured, and the average value is obtained. In order to obtain I _G and I _CH , the blank level is first examined. That is, without setting the sample S in the triple spectrometer, the triple spectrometer is operated for 10 minutes, and the blank level of the triple spectrometer is checked. After that, the sample S is set in the triple spectrometer, the triple spectrometer is operated for 10 minutes, the Raman spectrum is obtained, and the intensities I _G and I _CH (at the peak point) of the peak points in each region are set with the blank level as a reference. Calculate the height from the blank level to the peak value. This is measured at three or more points, and the average value is determined. For details, see Japanese Patent Application No. 7-3009.
Since it is described in the specification No. 19, this may be referred to.

When a Raman spectroscopic spectrum of a protective film provided with a lubricant is examined with a triple spectrometer, peaks due to C—C and C—H bonds of the lubricant may be observed. In such a case,
I _G and I _CH in the state where the peaks due to the C—C and C—H bonds of this lubricant are removed are obtained, and I _CH / I _G is obtained. Alternatively, the lubricant is removed in advance, and the Raman spectrum of the lubricant is examined with a triple spectrometer to obtain I _CH / I _G.

The support in the magnetic recording medium of the present invention is
It may be magnetic or non-magnetic. Generally, it is non-magnetic. For example, a flexible polymer material such as polyester such as PET, polyamide, polyimide, polysulfone, polycarbonate, olefin resin such as polypropylene, cellulose resin, or vinyl chloride resin is used.

On this flexible support, a metal thin film type magnetic film having a thickness of 500 to 5000 Å is provided by dry plating means such as vapor deposition or sputtering. Examples of the material of the magnetic particles forming the metal thin film type magnetic film include Fe,
In addition to metals such as Co and Ni, Co-Ni alloys, Co-P
t alloy, Co-Ni-Pt alloy, Fe-Co alloy, Fe
A -Ni alloy, an Fe-Co-Ni alloy, an Fe-Co-B alloy, a Co-Ni-Fe-B alloy, a Co-Cr alloy, or an alloy containing these different metals is used. Examples of the metal thin film type magnetic film include nitrides (for example, Fe-N, Fe-NO) and carbides (for example, Fe-C, Fe-CO) of the above materials.

A protective film having a thickness of 10 to 500 Å, especially 30 to 200 Å, is provided on the metal magnetic film. This protective film has the above characteristics. Such a protective film is
For example, a film can be formed by a sputtering means using graphite as a target. However, in forming this film, it is important to set the film forming conditions as follows. Sputtering gas; Mixed gas of inert gas (for example, Ar) and hydrogen gas Mixing ratio of inert gas and hydrogen gas; 100: 2.0-5
0 degree of vacuum; 2.0 × 10 ^{−1 to} 2.0 × 10 ⁻⁵ Torr sputter voltage; 100 to 800 v tape speed; 0.01 to 0.4 m / min That is, the film is formed under the above conditions. By
A carbon-based protective film having the above characteristics can be obtained. In particular, a carbon-based film (carbon film, Si-containing carbon film, F-containing carbon film) in which hydrocarbon is present is obtained, and this protective film has appropriate toughness, and as a result, durability is improved.

After the metal magnetic film and the protective film are formed as described above, a film of a fluorine-based lubricant is provided to a thickness of about 20 to 70Å by means such as dipping or ultrasonic spraying. As the lubricant, for example, HOOC-CF ₂ (OC ₂ F ₄ ) _p (OCF ₂ ).
HOCH, a carboxyl group-modified perfluoropolyether such as _q -OCF ₂ -COOH, F- (CF ₂ CF ₂ CF ₂ O) _n -CF ₂ CF ₂ COOH
₂ -CF ₂ (OC ₂ F ₄ ) _p (OCF ₂ ) _q -OCF ₂ -CH ₂ OH Alcohol-modified perfluoropolyether, such as one or part of the molecule saturated with an alkyl group A hydrocarbon group, an unsaturated hydrocarbon group, or an aromatic hydrocarbon group,
Those having other functional groups may be mentioned. Specific examples include FOMBLINZ DIAC and FOMBLINZ DOL manufactured by Montecatini, and Demnum SA manufactured by Daikin Industries.

[0018]

[Embodiment 1] FIG. 1 is a schematic view of a first embodiment of an 8 mm VTR magnetic tape according to the present invention. In FIG. 1, 1 is about 6
It is a support made of PET (polyethylene terephthalate) having a thickness of μm.

Reference numeral 2 is a 2000 Å thick Co metal magnetic film provided on the surface of the support 1 by the oblique deposition method. 3 is
A 2000Å thick Al—Cu alloy film (back coat layer) provided on the back surface of the support 1 by a vapor deposition method. 4 is 1
It is a protective film with a thickness of 00Å. The protective film 4 is a carbon-based film containing hydrocarbon and is provided on the Co metal magnetic film 2 by sputtering under the following conditions.

Target material: Graphite Sputtering gas; Ar + H ₂ mixed gas (7.5: 2.5) Mixed gas flow rate; Vacuum degree of 9 × 10 ^-6 Torr is 4.0 ×
10 ⁻³ Torr Sputtering voltage: 480v Tape speed: 0.5 m / min About this carbon-based film 4, triple made by Spex
A Raman spectroscopic spectrum obtained by irradiating an Ar laser (wavelength 488 nm) with an output of 300 mW using a spectrometer is shown in FIG. 2 (measured before the fluorine-containing lubricants 5a and 5b are provided). According to this, 1
In the region of 540 cm ⁻¹ , the intensity I _G due to diamond-like carbon peaks at 210 cps and 3000 c
The intensity I _CH resulting from the C—H bond of the hydrocarbon molecules contained in the diamond-like carbon film in the region of m ⁻¹
However, a peak of 273 cps is recognized.

Reference numerals 5a and 5b are fluorine-containing lubricants (FOMBLINZ DIAC) having a thickness of 20Å provided on the surface.

[0022]

Example 2 Example 1 was repeated except that the sputtering conditions for forming the protective film 4 were as follows. Target material: Graphite Sputtering gas; Ar + H ₂ mixed gas (8: 2) Mixed gas flow rate; 9 × 10 ⁻⁶ Torr vacuum degree is 4.0 ×
10 ⁻³ Torr Sputtering voltage; 450 v Tape speed; 0.5 m / min About this carbon-based film 4, triple made by Spex
A Raman spectroscopic spectrum obtained by irradiating an Ar laser (wavelength 488 nm) with an output of 300 mW using a spectrometer is shown in FIG. 3 (measured before the fluorine-based lubricants 5a and 5b are provided). According to this, 1
In the region of 540 cm ⁻¹ , the peak I _G due to diamond-like carbon is 200 cps and 3000 c
The intensity I _CH resulting from the C—H bond of the hydrocarbon molecules contained in the diamond-like carbon film in the region of m ⁻¹
However, a peak of 180 cps is recognized.

[0023]

Example 3 The procedure of Example 1 was repeated except that the sputtering conditions for forming the protective film 4 were as follows. Target material: Graphite Sputtering gas; Ar + H ₂ mixed gas (9: 1) Mixed gas flow rate; Vacuum degree of 9 × 10 ⁻⁶ Torr is 4.0 ×
10 ⁻³ Torr Sputtering voltage; 420v Tape speed; 0.5 m / min About this carbon-based film 4, triple made by Spex
A Raman spectroscopic spectrum obtained by irradiating an Ar laser (wavelength 488 nm) with an output of 300 mW using a spectrometer is shown in FIG. 4 (measured before the fluorine-containing lubricants 5a and 5b are provided). According to this, 1
In the region of 540 cm ⁻¹ , the peak I _G due to diamond-like carbon is 204 cps and 3000 c
The intensity I _CH resulting from the C—H bond of the hydrocarbon molecules contained in the diamond-like carbon film in the region of m ⁻¹
Is observed at a peak of 122 cps.

[0024]

Comparative Example 1 The procedure of Example 1 was repeated except that the sputtering conditions for forming the protective film 4 were as follows. Target material: Graphite Sputtering gas; Ar + H ₂ mixed gas (6.5: 3.5) Mixed gas flow rate; Vacuum degree of 9 × 10 ⁻⁶ Torr is 3.2 ×
10 ⁻³ Torr Sputtering voltage; 500 v Tape speed; 0.3 m / min About this carbon-based film 4, triple made by Spex
A Raman spectroscopic spectrum obtained by irradiating an Ar laser (wavelength 488 nm) with an output of 300 mW using a spectrometer is shown in FIG. 5 (measured at a stage before the provision of the fluorine-based lubricants 5a and 5b). According to this, 1
In the region of 540 cm ⁻¹ , the peak I _G due to diamond-like carbon is 200 cps and 3000 c
The intensity I _CH resulting from the C—H bond of the hydrocarbon molecules contained in the diamond-like carbon film in the region of m ⁻¹
Is recognized as a peak of 300 cps.

[0025]

Comparative Example 2 The procedure of Example 1 was repeated, except that the sputtering conditions for forming the protective film 4 were as follows. Target material: Graphite Sputtering gas; Ar gas Mixed gas flow rate; Vacuum degree of 9 × 10 ⁻⁶ Torr is 3.2 ×
10 ^-3 Torr Sputtering voltage; 520v Tape speed; 0.5m / min About this carbon-based film 4, triple made by Spex
A Raman spectroscopic spectrum obtained by irradiating an Ar laser (wavelength: 488 nm) with an output of 300 mW using a spectrometer is shown in FIG. 6 (measured before the provision of the fluorine-based lubricants 5a and 5b). According to this, 1
Although a peak due to diamond-like carbon was observed in the region of 540 cm ^-1 , 2900 ± 200c
No peak due to C—H bond is observed in the m ⁻¹ region.

[0026]

[Characteristics] The still durability of the magnetic tape for 8 mm VTR obtained in each of the above examples was examined. The results are shown in Table 1. Table-1 I _CH / I _G still durability (hr) Example 1 1.30 4.8 Example 2 0.90 5.4 Example 3 0.60 5.2 Comparative Example 1 1.50 1.2 Comparative Example 2 0 1.2 * Still durability is the time required for output to decrease by 3 dB when still reproduction is performed in an atmosphere of 20 ° C. and 50% RH. It can be seen that the protective film provided according to the present invention has excellent durability.

[0027]

EFFECTS OF THE INVENTION A product having excellent durability can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view of a magnetic tape according to the present invention.

2 is a Raman spectrum of the protective film of the magnetic tape of Example 1. FIG.

FIG. 3 is a Raman spectrum of the protective film of the magnetic tape of Example 2.

FIG. 4 is a Raman spectrum of the protective film of the magnetic tape of Example 3.

5 is a Raman spectrum of the protective film of the magnetic tape of Comparative Example 1. FIG.

FIG. 6 is a Raman spectrum of the protective film of the magnetic tape of Comparative Example 2.

[Explanation of symbols]

 1 Support 2 Co Metal Magnetic Film 3 Al-Cu Alloy Film 4 Diamond-Like Carbon Film (Protective Film)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Shiga 2606 Akabane, Kai-cho, Haga-gun, Tochigi Prefecture Kao Corporation Company Information Science Laboratory

Claims (5)

[Claims] 1. A magnetic recording medium having a support, a magnetic film, and a protective film, wherein the protective film has a C component and an H component, and has a Raman spectrum of 1550 ± 50.
The intensity has a peak of I _{G in} the region of cm ⁻¹ and 2
A magnetic recording medium characterized in that the intensity has a peak of I _{CH in} a region of 900 ± 200 cm ⁻¹ , and the I _CH / I _G has a value within a range of 0.1 to 1.4. 2. A magnetic recording medium having a support, a magnetic film and a protective film, wherein the protective film is a carbon-based film in which hydrocarbon is present, and has a Raman spectrum of 1550 ± 50.
The intensity has a peak of I _{G in} the region of cm ⁻¹ and 2
A magnetic recording medium characterized in that the intensity has a peak of I _{CH in} a region of 900 ± 200 cm ⁻¹ , and the I _CH / I _G has a value within a range of 0.1 to 1.4. 3. A magnetic recording medium having a support, a magnetic film, and a protective film, wherein the protective film is a diamond-like carbon-based film in which hydrocarbon is present, and has a Raman spectrum of 1550 ± 50.
The intensity due to diamond-like carbon has a peak of I _G in the region of cm ⁻¹ and is 2900 ± 200.
In the region of cm ⁻¹ , the strength due to the C—H bond of the hydrocarbon contained in the diamond-like carbon film is I _CH
The magnetic recording medium is characterized by having a peak of I _CH / I _G within the range of 0.1 to 1.4. 4. The protective film has I _CH / I _G of 0.4 to
A value within the range of 1.3.
The magnetic recording medium according to claim 3. 5. A magnetic film on a flexible support,
The magnetic recording medium according to claim 1, which is a magnetic tape in which a protective film is provided on the magnetic film and a lubricant is provided on the protective film.