JPS61284830A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a medium which decreases the wear of a magnetic head and decreases the medium noise by disposing an electron beam curing resin layer in which metallic atoms are partially disposed on a high-polymer film and providing a magnetic recording layer consisting of a thin ferromagnetic metallic film thereon. CONSTITUTION:This magnetic recording medium has the high-polymer film 1 consisting of a PE terephthalate film, the electron beam curing resin layer 2, a partially oxidized layer 3 obtd. by the formation of the thin ferromagnetic metallic film 4 and a stearic acid film 5 which is a protective lubricating film formed by a vacuum deposition method. A soln. prepd. by dissolving a dipentaerythritol hexaacrylate as the electron beam curing resin in a toluene is coated on the above-mentioned film and is dried; thereafter, the film is conducted from the run along a cylindrical can in the oxygen partial pressure and is subjected to diagonal vapor deposition of No-Ni by a vapor deposition method at the continuously changing incident angles to form the thin ferromagnetic metallic film thereon. An electron beam is irradiated on the film right after such formation to cure the resin film by the electron beam.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording medium that can be used for high-density magnetic recording.

Conventional technology The conventional magnetic recording layer that has been widely used in practical use is 1.
- Fe203, Go doped 1-ve2o3
A ferromagnetic metal such as , CrO2, or iron or an alloy fine powder magnetic material is dispersed in an organic binder such as vinyl chloride, vinyl acetate copolymer, styrene-butadiene copolymer, or epoxy resin to form a polymer film or the like. This is a coated magnetic layer that is coated and dried on a substrate.

In recent years, as the demand for high-density recording has increased, so-called metal thin film magnetism, in which a ferromagnetic metal thin film is used as the magnetic recording layer, has great expectations for providing an excellent signal-to-noise ratio (hereinafter referred to as S/N) in the high-density range. Recording media are attracting attention, and efforts are being made to put them into practical use.

[For example, foreign journal: IEEI Magnetics Society Bulletin (X
EK K Transaction on Ma(n
etics)ToI! , MAG-10, NO-2, P
See P. 36 Ka. 473 (1974)] The main objective of improving such magnetic recording media is to improve the durability of the magnetic recording layer while maintaining excellent electromagnetic conversion characteristics. Therefore, many proposals have been made regarding this, and Go--P, Co--Ni, which are generally used as magnetic recording layers.
A method of using a protective film on a ferromagnetic metal thin film such as -P% Go -Ni -0 film to reduce friction with the mechanical material of a magnetic head or a traveling system [for example, JP-A-52-1537
No. 07, JP-A-63-88704, JP-A-59-17
1026] or by forming fine irregularities on a polymer film and placing a ferromagnetic metal thin film on top of it, it is possible to reduce the contact area and improve the abrasion resistance and running performance. It has been successful in some cases. [For example, JP-A-59-
84928 and Japanese Patent Application Laid-open No. 121631/1984].

Problems to be Solved by the Invention However, with the above-mentioned configuration, it is not possible to maintain a good S/N ratio when the magnetic head is an alloy-based head, especially one in which a part of the magnetic path is formed by sputtering. There was a problem.

In view of the above-mentioned problems, the present invention provides a magnetic recording medium with less wear on the magnetic head and less media noise.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording medium of the present invention includes an electron beam-cured resin layer in which metal atoms are partially diffused on a polymer film, and a ferromagnetic metal thin film on top of the electron beam-cured resin layer in which metal atoms are partially diffused. It is equipped with a magnetic recording layer consisting of.

Function The magnetic recording medium of the present invention has the above-described structure, and when it slides with a magnetic head at high speed, the electron beam-cured resin hardens and interacts with the magnetic recording layer to form a surface that shrinks to form fine irregularities. The effect of the shape and the effect of the partial diffusion layer, which makes the stress transmission envelope continuous and effectively disperses stress, equalizes the impact force on the head and reduces wear. Since the irregularities are extremely fine, the S/N ratio can also be improved.

EXAMPLES Below, magnetic recording media according to examples of the present invention will be described with reference to the drawings.

FIG. 1 is an enlarged sectional view of a magnetic recording medium according to a first embodiment of the present invention.

In FIG. 1, 1 is a polymer film made of polyethylene terephthalate film having a thickness of 7.2 μm, 2 is an electron beam cured resin layer, and 3 is a partially oxidized layer formed by forming a ferromagnetic metal thin film 4. 5 is a protective lubricating film, which is a stearic acid film with a thickness of about 60× formed by vacuum deposition.

Dipentaerythritol hexaacrylate dissolved in toluene at a concentration of 1.0% by weight was coated as an electron beam curing resin, and after drying, it was introduced into a vacuum evaporator from the atmosphere and first I X 10-'('rorr). Co-Ni (Ni; 20 wt%) was deposited obliquely on a cylinder with a diameter of 1 m along the yang in an oxygen partial pressure of A ferromagnetic metal thin film of 0.16 μm was formed, and immediately after that, 1
It was irradiated with an electron beam of 00 KV and 5 Mrad for electron beam curing. By doing this, Go-Ni becomes 0.
A partially diffused layer is formed on the surface layer 370X of the electron beam cured resin with a thickness of 9 μm, and the surface of the magnetic recording layer is affected by curing shrinkage. Assuming that the average roughness of the polymer film is Ra (2,0~
4.3) xRa. In this example, since Ra was selected to be 6OA, a magnetic recording layer surface of 200 μm could be obtained.

Note that this magnification relationship of Ra can be changed by the resin thickness and the irradiation energy per unit time of the electron beam, and can be adjusted and optimized while looking at the S/N ratio.

As a comparative example to be compared with the present invention, JP-A-59-1
Using a polyethylene terephthalate film disclosed in Japanese Patent Publication No. 21631 and designed to have almost the same Ra of 20OA, the same vapor deposition as in the example was performed to form a ferromagnetic metal thin film of 0.15 μm and a stearic acid (60%) film. and obtained a magnetic tape.

Using a so-called metal-in-gap head in which a sendust alloy film was formed in the gap by sputtering (gap length 0.2 μm), the time required for the envelope to decrease to 80% or less was compared. The results were as shown in the table. The recording wavelength is o, 49 μm.

As described above, according to this embodiment, an electron beam-cured resin layer in which metal atoms are partially diffused is arranged on a polymer film.
By providing a ferromagnetic metal thin film as a magnetic recording layer on top of this, a good reproduction envelope can be maintained for a long time during short wavelength recording and reproduction using a metal-in-gap head.
Can be maintained in various environments.

A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is an enlarged sectional view of a magnetic recording medium according to a second embodiment of the present invention. In FIG. 2, 6 is a polyamide film with a thickness of 11 μm. Reference numeral 7 is an electron beam hardening resin layer 8, a Wb partial diffusion layer 9, and a Nb evaporation base layer of 650 μm. 7.8.9 Formation and electron beam curing The resin used was the same material as in Example 1, and the electron beam curing resin was prepared by reacting ethylene glycol, succinic acid, hexamethylene diisocyanate, and acrylic ester. A compound having an average molecular weight between crosslinking points of about 230 was used as B.

After placing the Nb fat layer, the surface temperature of the diameter 6ocIx was 18
Along the 0'C cylindrical can, there is only a vertical component,
1x Go-Cr (Or + 19.7wt%)
Thickness 0 by electron beam evaporation in a vacuum of 1o-7 Torr
．． A ferromagnetic metal thin film 10 made of a perpendicularly magnetized Co--Cr film of 2 μm is placed on top of the ferromagnetic metal thin film 10 with a partial pressure of 1×10−”Torr.
Inside, while a high frequency glow discharge of 13.56 MHz was generated, myristic acid was formed as a protective lubricant film 11 with a thickness of about 60 μm using an ion blasting method. Surface roughness R
A was 240 MU and 200 MU for Mu tape and B tape, respectively.

Using a metal-in-gap ring type head with a gap length of 0.16 μm, we performed recording and playback of 0.36 μm and compared the time it took for the envelope to exceed 80q6 in the same way as in the first embodiment. 10%~16
% increase, and the °B tape was able to confirm almost the same performance in the range of -6% to +5%.

Also, as a result of examining the change in dropout in each environment, it was found to be up to 1.3 times the initial value under the head tape usage condition after 10oO hours, but in the comparative example used in Example-1, it was 1.3 times the initial value after 500 hours. Later, it increased by about 6 times.

As described above, this embodiment has the advantage of being able to maintain good envelope playback waveforms and dropout performance over a long period of time while achieving extremely high recording density using a metal-in-gap type ring head. There is.

In the first and second embodiments, the polymer films were made of polyethylene terephthalate and polyamide, respectively, but they may also be made of polyimide, polyvinyl chloride, polycarbonate, cellulose triacetate, polyethylene naphthalate, polysulfone, or the like.

As shown in the examples, the electron beam curing resin includes a reaction product with a polyol, dicarboxylic acid, diisocyanate, (meth)acrylic acid, and (meth)acrylic acid ester, and the average molecular weight between the crosslinking points is There are many combinations, such as reaction products of polyols and (meth)acrylic acid, reaction products of polyols, dicarboxylic acids, and (meth)acrylic esters, and the like.

The base layer was made of Wb, but other materials were Si, Ga, and Ti.

Mo, Ta, Ru, Rh, in/. It may also be Cu or the like.

The ferromagnetic metal thin film was Go-Ni-0, co-Or, but also Go-Ni, Go-Fe+Go-0, co-O
s.

Go-3i, Go-Ga, Go-Ti, G
o-Mo, Go-Ta.

Go-Ru, Go-Rh, Go-mu JIGO-Cu, G
O-W.

Go-8m, Go-Ni-P, Go-M(-0
etc.

Effects of the Invention As described above, according to the present invention, in combination with a metal-in-head type ring-shaped magnetic head useful for high recording density, good initial S/N (reproduction envelope waveform) and dropout can be achieved. It is possible to obtain excellent effects such as maintaining performance for a long time even under various environmental conditions.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of a magnetic recording medium according to a first embodiment of the invention, and FIG. 2 is an enlarged sectional view of a magnetic recording medium according to a second embodiment of the invention. 1.6...Polymer film, 2.7...
- Electron beam curing resin, 3,8...partial diffusion layer, 9...base layer, 4,1o...ferromagnetic metal thin film. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
--Polymer film Figure 1
2-11 Den I Heem Hardening April A Cloudy 3--Ippang Bunkoshin] 4-11 Chen Toa Heyday in full bloom

Claims (1)

[Claims] A magnetic recording medium characterized in that an electron beam-cured resin layer in which metal atoms are partially diffused is arranged on a polymer film, and a magnetic recording layer made of a ferromagnetic metal thin film is arranged thereon.