JPS63166043A - Optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium having excellent weatherability and adhesiveness by polymerizing the monomer of an org. compd. having a carbonyl group to form an underlying layer consisting of a plasma-polymerized film having a specific refractive index. CONSTITUTION:This recording medium has the underlying layer consisting of the plasma-polymerized film on a substrate. The plasma-polymerized film is formed by polymerizing the monomer of the org. compd. having the carbonyl group and the refractive index at 6,328Angstrom of the plasma-polymerized film is confined to 1.3-1.7. The denseness of the film is not obtainable so that the shielding of moisture, etc., from the substrate 11, etc., is not possible and the adhesiveness is insufficient if the refractive index is below 1.3. The hardness of the polymerized film increases and the adhesion of the polymerized film to a sputtered film, vapor deposited film, etc., for example, an intermediate layer 15 and a protective layer 16, etc., to be installed in contact with said film is defective if the refractive index exceeds 1.7. The optical recording medium having the excellent weatherability and adhesiveness is thereby obtd.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium such as a magneto-optical recording medium that records and reproduces information using heat and light such as laser light.

Prior art and its problems One type of optical recording medium is a magneto-optical memory medium.

As a recording medium for magneto-optical memory, MnB1. MnAfiGe%MnSb.

MnCuB1%GdFe%TbFe.

GdCo, PtCo, TbCo, TbFeCo, GdFeCo.

TbFeO3, Gd1G, GdTbFe, GdTbFe
CoB1. Materials such as CoFe and 04 are known.
These methods include vacuum evaporation, sputtering, etc.
It is formed as a thin film on a transparent substrate such as plastic or glass. Common characteristics of these magneto-optical recording media include the fact that the axis of easy magnetization is perpendicular to the film surface, and that the Kerr effect and Faraday effect are large.

As a recording method for a magneto-optical recording medium that takes advantage of this property, there are, for example, the following methods.

First, the entire film is magnetized to "0", that is, uniformly (this is called erasing). Next, a laser beam is irradiated onto the part where you want to record "1". The temperature of the area irradiated with the laser beam rises, and when it approaches the Curie point and further exceeds the Curie point, it approaches the coercive force Hc. Then, when the laser beam is turned off and the temperature is returned to room temperature, the magnetization is reversed due to the energy of the demagnetizing field. This is inverted and a signal of "1" is recorded.

Furthermore, since the initial state of recording is "0", "0" remains in the area where the laser beam is not irradiated.

Reading of a recorded magneto-optical memory is similarly performed by using a laser beam and by rotating the plane of polarization of reflected light due to the direction of magnetization of the laser beam irradiation light, that is, by utilizing the magneto-optic effect.

First, such a medium is required to have a Curi point of about 100 to 200° C. and a compensation point of around room temperature.

Second, there are relatively few defects such as grain boundaries that cause noise.

Thirdly, a magnetically and mechanically uniform film can be obtained over a relatively large area without using methods such as high-temperature film formation or long-time film formation.

In response to such demands, among the above-mentioned materials, amorphous perpendicular magnetic thin films of rare earth-transition metals have recently attracted much attention.

However, when magneto-optical recording media made of such rare earth-transition metal amorphous thin films are stored in contact with the atmosphere, the rare earth elements are selectively corroded by oxygen and water in the atmosphere that enter through the substrate. Otherwise, it becomes oxidized, making it impossible to record or reproduce information.

Therefore, in general, many researches have been made on structures in which a protective intermediate layer is provided between the magnetic thin film layer and the substrate.

These intermediate layers include, for example, inorganic vacuum-deposited films such as 5iO1Si02, or room-temperature curable resin coating intermediate layers.

However, these intermediate layers do not provide partial moisture resistance, and there are problems such as storage deterioration.

In order to deal with such bad luck, Japanese Patent Application Laid-Open No. 60-1774
No. 49 discloses a proposal to improve weather resistance by using glass in the intermediate layer.

On the other hand, the present inventors formed a plasma polymerized film on a substrate,
We are proposing ways to improve adhesion and weather resistance (
(Japanese Patent Application No. 180729/1983).

In addition, in order to improve the characteristics and durability of the medium, especially the adhesion between the substrate and the magnetic thin film layer, a plasma polymerized film is formed on the plasma-treated substrate, and a magnetic thin film layer is formed on the plasma-treated substrate. A proposal has been made to provide a layer (Japanese Patent Application No. 181327-1983).

Furthermore, in order to prevent deterioration due to moisture etc. from the surface of the magnetic thin film layer of the medium, a plasma polymerized film is formed on the surface of the magnetic thin film layer and used as a protective layer. We have proposed the provision of a protective layer containing a curable compound (patent application 1986-
No. 182767, No. 61-183285).

In addition, in order to improve the characteristics of the medium, especially durability and storage stability in high humidity atmospheres, a plasma polymerized film base layer is provided on the substrate, and the base layer is applied directly or on top of this plasma polymerized film base layer. proposed a method of forming an amorphous magnetic thin film layer of rare earth metals and transition metals, and forming a plasma polymerized film protective layer on this magnetic thin film layer (Japanese Patent Application No. 60-184).
No. 799).

Furthermore, in JP-A No. 60-260628, a compound selected from tetrafluoroethylene, acrylonitrile, acrylic acid, metal methacrylate, vinyl chloride, and vinylidene chloride is disclosed.
A proposal has been disclosed to coat a thermoplastic resin molded body with a plasma polymerized film containing one or more species to improve weather resistance.

However, even these proposals are insufficient in terms of adhesion with the intermediate layer and protective layer and weather resistance, and do not necessarily satisfy the required properties, and there is a need for magneto-optical recording media with even better properties. .

Note that such a problem also occurs in optical recording media having a so-called phase transition type recording layer.

■Object of the Invention An object of the present invention is to provide an optical recording medium with excellent weather resistance and adhesive properties.

■Disclosure of invention Such objects are achieved by the present invention as described below.

That is, the first aspect of the present invention is an optical recording device having a plasma polymerized film base layer on a substrate, an intermediate layer on the plasma polymerized film base layer, and a recording layer on the intermediate layer. a medium, wherein the plasma polymerized film is obtained by polymerizing a monomer of an organic compound having a carbonyl group,
This optical recording medium is characterized in that the plasma polymerized film has a refractive index of 1.3 to 1.7 in 6328 people.

Further, the second invention has a plasma polymerized film base layer on the substrate, and has an intermediate layer on the plasma polymerized film base layer,
An optical recording medium having a recording layer on this intermediate layer, and a plasma polymerized film protective layer formed on the recording layer directly or via a protective layer, the plasma polymerized film being an organic material having a carbonyl group. The optical recording medium is obtained by polymerizing compound monomers and is characterized in that the plasma polymerized film has a refractive index of 1.3 to 1.7 at 6328λ.

■Specific structure of the invention Hereinafter, a specific configuration of the present invention will be explained in detail.

FIG. 1 and FIG. 2 are sectional views each showing an embodiment of a magneto-optical recording medium among the optical recording media of the present invention.

In the embodiment shown in FIG. 1, the magneto-optical recording medium 1 of the present invention
has a plasma polymerized film base layer 12 on a substrate 11, and has an intermediate layer 15 on this plasma polymerized film base layer 12,
On this intermediate layer 15 is an amorphous magnetic thin film layer 14 of rare earth-transition metal as a recording layer.

A protective layer 1 is further formed on the amorphous magnetic thin film layer 14.
6 and a protective film 19.

Further, in the embodiment shown in FIG. 2, a plasma polymerized clothing protective layer 17 is further formed directly or via a protective layer 16 on the rare earth-transition metal amorphous magnetic thin film layer 14. A protective film 19 is provided on the plasma polymerized film protective layer 17 .

In the present invention, a plasma polymerized film base layer 12 (aspects shown in FIGS. 1 and 2) and a plasma polymerized film protective layer 17 (second embodiment) are used.
The plasma-polymerized membrane of the embodiment shown in the figure) is obtained by polymerizing an organic compound monomer having a carbonyl group.

As examples of organic compounds having carbonyl groups,
Aldehydes, such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, heptaldehyde, acrylaldehyde, benzaldehyde, crotonaldehyde, etc. Ketones, such as acetone, methyl ethyl ketone, diethyl ketone, isobutyl methyl ketone, Acetophenone, propiophenone, hensifhenone, cyclobutanone, cyclohexanone, 4- and ron, anthrone, pyridone, pyrrolidone, methyl vinyl ketone, etc.; Ketenes, such as phenyl ketene, dimethyl ketene, etc.; Carboxylic acids, such as formic acid, acetic acid, propionic acid, Butyric acid, isobutyric acid, valeric acid, isovaleric acid, acrylic acid 1, propiolic acid, methacrylic acid, crotonic acid, isocrotonic acid, etc.: Carboxylic acid esters, such as methyl acrylate, methyl methacrylate, phenyl acetate, diethyl malonate ,
Ethylene diacetate, diethyl succinate, etc.: Lactones and lactams, such as γ-butyrolactone, (γ-1δ-)valerolactone, 2-pyrrolidone, 2
- Piperidone, etc.: Examples include carboxylic acid peracids, carboxylic acid anhydrides, hydroxy acids with carboxyl groups, alkoxy acids, oxoacids, amino acids, amic acids, etc. Among them, acetone, acrylic acid, methacrylic acid , methyl acrylate and the like are preferred.

These may be used alone or in combination of two or more.

In the present invention, the plasma polymerized film has a refractive index n of 1.3 to 1.7, preferably 1.4 to 1.6 in 6328 people.
It is better to

The refractive index is set to such a value because if n is less than 1.3, the film will not be dense enough to absorb moisture from the substrate 11, etc., and the adhesion will not be sufficient. In addition, if it exceeds 1.7, the hardness of the polymer film will increase, and the adhesion with the sputtered film, vapor deposited film, etc. placed in contact with the polymer film, such as the intermediate layer 15 and the protective layer 16 described later, will be poor. Because it will be.

In addition, in the present invention, glass (described later) that is preferably used as a material for the intermediate layer 15, the protective layer 16, etc. is 63
It is preferable that n at 28λ is about 1.5, and the plasma polymerized film has a value similar to this.

In order to obtain such n, plasma polymerization conditions such as a low film formation rate and low pressure may be selected as described later.

In the present invention, a plasma polymerized film base layer 12 (aspects shown in FIGS. 1 and 2) and a plasma polymerized film protective layer 17 (second embodiment) are used.
The thickness of each of the embodiments shown in the figure is preferably 10 to 1000 people, preferably 50 to 600 people.

This thickness is chosen because the effectiveness of the present invention cannot be obtained with less than 10 people, and there is no difference in the effectiveness of the present invention even with more than 1000 people, so there is no need to increase the thickness above this value. be.

Note that the film thickness may be measured using an ellipsometer or the like.

Such film thickness can be controlled by controlling the reaction time, raw material gas flow rate, etc. during plasma polymerized film formation.

The plasma polymerized film base layer 12 is a polymerized film formed by bringing discharge plasma of the above-mentioned raw material gas into contact with the substrate.

Further, the plasma polymerized film protective layer 17 (the embodiment shown in FIG. 2) is a plasma polymerized film formed on the magnetic thin film layer 14 similarly to the underlayer 12.

By forming such a protective layer 17, moisture resistance is further improved.

The plasma polymerized film protective layer 17 may be provided on the magnetic thin film layer 14 via a protective layer 16 made of the same material as the intermediate layer 15, which will be described later.

To give an overview of the principle of plasma polymerization, when a gas is kept at a low pressure and an electric field is applied, the free electrons present in small amounts in the gas are accelerated by the electric field due to the very large intermolecular distance compared to normal pressure, and are accelerated at 5 to 10 eV. Obtain the kinetic energy (electron temperature) of

When these accelerated electrons collide with atoms and molecules, they disrupt atomic and molecular orbits and dissociate them into chemical species that are unstable under normal conditions, such as electrons, ions, and neutral radicals.

The dissociated electrons are again accelerated by the electric field, causing them to dissociate from other atoms and molecules, and this chain reaction quickly turns the gas into a highly ionized state. And this is called plasma gas.

Gas molecules have fewer chances of colliding with the electric charge r-, so they do not absorb much energy and are kept at a temperature close to room temperature.

A system in which the kinetic energy of electrons (electron temperature) and the thermal motion of molecules (gas temperature) are separated is called a low-temperature plasma. The present invention aims to utilize this situation to form a plasma polymerized film on a substrate. Note that since low-temperature plasma is used, there is no thermal effect on the substrate.

An example of an apparatus for forming a plasma polymerized film on a substrate surface is shown in FIG. FIG. 3 shows a plasma polymerization apparatus using a frequency variable power source.

In FIG. 3, raw material gas is supplied to the reaction vessel R from a raw material gas source 511 or 512 via mass flow controllers 521 and 522, respectively. Gas source 5
When separate gases are supplied from 11 or 512, they are mixed in a mixer 53 and supplied.

The raw material gases can each have a flow rate range of 1 to 250 LIIJ2/min.

Inside the reaction vessel R, a substrate to be processed 111 is supported by one rotary electrode 552 .

Rotary electrodes 552 are placed across the substrate 111 to be processed.
An electrode 551 facing the is provided.

One electrode 551 is connected to, for example, a variable frequency power source 54, and the other rotary electrode 552 is grounded at 8.

Furthermore, a vacuum system for evacuating the inside of the reaction vessel R is provided, and this includes an oil rotary pump 56, a liquid nitrogen trap 57, an oil diffusion pump 58, and a vacuum controller 59. These vacuum systems operate within the reaction vessel at 0. Less than ITorr, preferably 0.005-0.0
Maintain a vacuum level of 8 Torr.

In the operation, the inside of the reaction vessel R is first set at 1O-5 Torr.
Evacuate the inside of the container until the amount is below, then process gas or the specified flow! In step 11, the mixture is supplied into the container in a mixed state.

And Sei IIS! The rate is preferably 50 to 200 people/nim.

At this time, the vacuum in the reaction vessel is controlled to be less than 0.1 Torr, preferably in the range of 0.0 to 0.08 Torr (7).

When the flow rate of the source gas becomes stable, the power is turned on.
In this way, a polymer 11Q is formed on the plasma on the substrate.

In addition, when a liquid monomer is used as a raw material in the present invention, a container containing a liquid monomer may be placed in a constant temperature bath at the gas source 511, 512 in FIG.

Note that Ar, N2, He, H2, etc. may be used as the carrier gas.

Further, the applied current, processing time, etc. may be set to normal conditions.

As the plasma generation source, in addition to high frequency discharge, microwave discharge, direct current discharge, alternating current discharge, etc. can be used.

In the present invention, since the operating pressure is particularly low, it is preferable to use a magnetron system that also uses a magnetic field.

In the case where a liquid monomer is used as a raw material in the present invention, a container containing the liquid monomer may be placed in a constant temperature bath at the gas sources 511 and 512 in FIG.

The C content of the plasma polymerized film thus formed is 3
It is preferably 0 to 90 at%.

In addition, H in the plasma polymerized film is generally 5 to 4'Oat
Contains about %.

Note that the content of C, H, and other elements in the plasma polymerized film may be analyzed by SIMS (secondary ion mass spectrometry) or the like. When SIMS is used, the amount may be calculated by counting C, H, and other elements on the surface of the plasma polymerized film.

Alternatively, while performing ion etching with Ar etc.,
, H, and other elements may be measured and calculated.

Regarding SIMS measurement, please refer to Volume 3 of Surface Science Basic Course (
1984) Fundamentals and Applications of Surface Analysis (p70) “SI
MS and LAMMA”.

Furthermore, the C=0 group present in the plasma polymerized film is FTI
Confirmed by R etc.

The substrate 11 used in the optical recording medium of the present invention is made of resin.

Preferred resins include acrylic resin, polycarbonate resin, epoxy resin, polymethylpentene resin, and the like.

Among these resins, polycarbonate resins are preferred in terms of durability, particularly resistance to warping and the like.

The polycarbonate resin in this case may be any of aliphatic polycarbonate, aromatic-aliphatic polycarbonate, and aromatic polycarbonate, but aromatic polycarbonate resin is particularly preferred.
Among these, polycarbonate resins made from bisphenol are preferred in terms of melting point, crystallinity, handling, etc.
Among them, bisphenol A type polycarbonate resin is most preferably used. In addition, the number average molecular weight of the polycarbonate resin is to, ooo to ts, ooo
It is preferable that the degree of

The refractive index 2 of such a substrate 11 at 830 nm is usually 1,
It is about 55 to 1.59.

Note that since recording is performed through the substrate 11, the transmittance for writing light or reading light is set to 86% or more.

In addition, the record is on the board! Since the reading is carried out through 1, the transmittance for the old light or readout light is set to be 86% or more.

Further, the substrate 11 is usually disk-shaped, and has 1.2 to 1.
The thickness should be approximately 5+a+m.

Tracking grooves may be formed on the magnetic thin film layer forming surface of such a disk-shaped substrate.

The depth of the groove is about λ/8n, especially λ/6n~λ
/ l 2 n (where n is the refractive index of the substrate)
It is said that Further, the width of the groove is approximately the width of a track.

5 Usually, it is preferable to irradiate the write light and read light from the back side of the substrate, using the magnetic @ film layer located in the recessed part of the groove as a recording track part.

With this configuration, the writing sensitivity and the reading C/N ratio are improved, and the tracking control signal is also increased.

In addition, other shapes of the substrate may be used, such as a tape or a drum.

In the present invention, the plasma polymerized film base N12 may be formed on the plasma-treated substrate 11.

By plasma-treating the surface of the substrate 11, the substrate 1
1, the adhesive force between the substrate and the plasma polymerized film base layer 12 is improved.

The principle, method, formation conditions, etc. of the plasma treatment method for the surface of the substrate 11 are basically almost the same as those of the plasma polymerization method described above.

However, in principle, plasma processing uses an inorganic gas as a processing gas, and on the other hand, in the formation of the plasma polymerized film base layer 12 by the plasma polymerization method described above, in principle, an organic gas (in some cases, an inorganic gas may also be mixed) is used. ) is used as the raw material gas.

There are no particular limitations on the plasma processing gas of the present invention.

That is, H2, Ar, He, 02, N2, air, HN
,,O,,H20,No%H,O.

It may be appropriately selected from NOx such as No. 2, and may be used alone or in combination.

Further, the frequency of the plasma processing power source is not particularly limited, and may be any of direct current, alternating current, microwave, etc.

Note that the back surface of the substrate 11 (the magnetic thin film layer 14 as a recording layer)
A plasma polymerized film may also be provided on the side (on which no layer is provided).

The intermediate layer 15 in the present invention is made of a compound containing oxygen, carbon, nitrogen, sulfur, etc., such as SiO2,
SiO% A It N, A l 203, Si3N
4. Various derivative materials such as ZnS%BN, TiO2, TiN, etc. or mixtures thereof; Glasses such as borosilicate glass, barium borosilicate glass, aluminum borosilicate glass, etc., or those containing St, N4, etc. Any material can be used. Among them, Sin
, 40 to 80 wt % of borosilicate glass, barium borosilicate glass, aluminum borosilicate glass, and those in which a part of SiO2 is replaced with Si3N, etc. are preferable.

Among these, the following are particularly preferred.

(1) 40 to 60 wt% silicon oxide, Bad, Cab
, SrO, MgO, ZnO.

Contains 50 wt% or less of a divalent metal oxide such as pbo and/or 10 wt% or less of an alkali metal oxide, and boron oxide and/or aluminum oxide.

(2) Si and other metal or metalloid elements such as Ba and C
a, Sr, Mg, Zn, Pb, etc., one or more of An, H, and at least one of one or more alkali metal elements, and the Si atomic ratio in the total metal or semimetal is 0.3 to 0.9, further contains 0 and N, and O/(0+N) is 0.4 to 0.8.

The thickness of such an intermediate layer 15 is preferably 500 to 3,000, preferably 800 to 2,500.

If it is less than 500λ, the weather resistance will not be sufficient, and if it exceeds 1,500 people, it will be too thick and the sensitivity will decrease when used as a medium.

The intermediate layer 15 is formed by forming a layer of about 300 to 1000 layers using the above-mentioned glass layer as a protective layer base, and on top of this, 5i02,5iO1S i3 N4, AILN%
Aj! 203, ZnS, etc., or a mixture thereof, etc., as a dielectric layer with a dielectric material of 500~t sooλ
It is preferable that the layers be formed to a certain extent.

In this case, the dielectric layer has a refractive index of 1.8 at 800 nm.
~3.0 is preferable, and Si and rare earth metals and/or
or Afi, and preferably contains 0 and N.

In the present invention, information is magnetically recorded in the magnetic thin film layer 14 as a recording layer using a modulated heat beam or a modulated magnetic field, and the recorded information is reproduced by magneto-optical conversion. be. - The material of such a magnetic thin film layer 14 is Gd, Tb.
It is an amorphous film formed by sputtering, vapor deposition, etc. of an alloy of rare earth metals such as , and transition metals such as Fe, Co, etc., and contains Fe and Co as essential components.

In this case, the total amount of Fe and Co is 65 to 85 at%
It is preferable that

The remainder is substantially rare earth metals, especially Gd and/or
Or Tb.

And, as a suitable example, TbFeCo1GdFe
Co, GdTbFeCo, etc.

Note that these magnetic thin film layers contain C', A1, Ti% Pt, Si in a range of 10 at% or less.

Mo, Mn, V% Ni, Cu, Zn, Ge.

Au etc. may be contained.

In addition, as a rare earth element, Sc in a range of 10aL% or less,
Y, La, Ce, Pr, Nd, Pm.

Sm, Eu, Dy, Ho, Er, Tm, Yb.

It may also contain Lu or the like.

The thickness of one such magnetic thin film layer is 0.01 to 1#ir.
n is preferable.

Other materials for the recording layer include so-called phase transition type materials, such as Te-3e%Te-5e-5n1 Te-Ge%Te-In%Te-5n.

Te-Ge-5b-S.

Te-Ge-As-3i, Te-5i.

Te-Ge-3i-5b.

Te-Ge-B1゜ Te-Ge-I n-Ga.

Te-5i-Bi-TIL, Te-Ge-B1-In-3, Te-As-Ge-5b.

Te-Ge-5e-3゜ Te-Ge-5e.

Te-As-Ge-Ga.

Te-Ge-3-1n.

5e-Ge-T J2, 5e-Te-As.

5e-Ge-Tit-3b.

5e-Ge-Bi, 5e-5 (hereinafter, Special Publication 1974-41)
No. 902, Japanese Patent No. 1004835, etc.)
), T e OX 1 P b O, (Patent No. 974258)
, TeaX+VOX (Patent No. 974257), others, Te-Tl, Te-Tl-Si, 5e-Zn
-Sb, Te-5e-Ga.

Chalcogen-based alloys mainly composed of Te and Se such as TeN, Ge-5n, 5i-Sn, which cause an amorphous-crystalline transition, Ag-Zn, Ag-Al1. -Cu%Cu-Aj! In-5b, an alloy that changes color due to crystal structure changes such as
There are alloys that cause changes in crystal grain size.

Preferably, a protective layer 16 is provided on such a magnetic thin film layer 14.

As for the material of the protective layer 16, like the intermediate layer 15, glass and dielectric materials such as various oxides and nitrides are preferable, and the above-mentioned glass is particularly preferable.

The thickness of the protective layer 16 is generally about 300 to 1,500.

Note that the protective layer 16 may be formed by vacuum deposition, sputtering, or the like.

In the optical recording medium of the present invention, the protective film 19 may be made of various known organic substances.

More preferably, a radiation-curable compound cured with radiation such as an electron beam or ultraviolet rays is used.

The radiation-curable compounds to be used include acrylic acid, methacrylic acid, or their ester compounds, which have unsaturated double bonds that are sensitive to ionization energy and exhibit radical polymerizability, and acrylic double bonds such as diallyl phthalate. Examples include mercury, oligomers, and polymers containing or introducing into the molecule groups that can be crosslinked or polymerized by radiation irradiation, such as allylic double bonds, unsaturated double bonds such as maleic acid, and maleic acid derivatives. can.

As a radiation-curable monomer, a compound with a molecular weight of less than 2,000 is used, and as an oligomer, a compound with a molecular weight of ffi of 2,000 to 2,000 is used.
Toooo is used.

These include styrene, ethyl acrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol methacrylate, 1,6-hexane glycol diacrylate, 1,6-hexane glycol diacrylate, etc., but particularly preferred ones are Examples include pentaerythritol tetraacrylate (methacrylate), pentaerythritol acrylate (methacrylate), trimethylolpropane triacrylate (methacrylate), trimethylolpropane diacrylate (methacrylate), and polyfunctional oligoester acrylate (Aronix M-7100, M-540).
0, M-5500, M-5700, M-6250, M-
6500, M-8030, M-8060, M-8100
etc., Toagosei), Tuboran 40 in urethane elastomer
40) or the acrylic modified products of C0
Those with functional groups such as OH introduced, acrylates (methacrylates) of phenol ethylene oxide adducts, compounds with an acrylic group (methacrylic group) or ε-caprolactone-acrylic group attached to the pentaerythritol condensed ring represented by the following general formula, 1) (CH2=C)ICOOCH2)3-CCH
20H (Special Acrylate A) 2) (CH2=CHCOOCH2)3-CCH2
o) 13 (Special Acrylate B) 3) (CH2=CHCO(OC3Hs)n-OC
H2) 3-CCH2CH3 (Special acrylate C) (Special acrylate D) (Special acrylate E) CH2CH2C00CH=CH2 (Special acrylate F) In the formula, a compound where m = 1, a = 2, b = 4 (hereinafter referred to as special pentaerythritol) (referred to as condensate A), m = 1, a = 3, b = 3 compound (hereinafter referred to as special pentaerythritol condensate B), m = 1, a = 6, b =
o compound (hereinafter referred to as special pentaerythritol condensate C
), m=2, a=6, b=o (hereinafter referred to as special pentaerythritol condensate), and special acrylates represented by the general formula below.

8) CH2=CHCOO-(C)12 CH20)
4-COCH=CH2 (special acrylate H) (special acrylate (special acrylate J) A Niacrylic acid, X: polyhydric alcohol Y: polybasic acid (on special acrylate) 12) A (
-M-N-)-M-AA Niacrylic acid, M: dihydric alcohol N: dibasic acid (special acrylate) In addition, radiation-curable oligomers include polyfunctional oligoester acrylates and urethane represented by the following general formula. Examples include acrylic modified elastomers, and those into which functional groups such as C0OH are introduced.

, (wherein R1, R2: alkyl, n: integer) Alternatively, a radiation-curable compound obtained by radiation-sensitizing modification of a thermoplastic resin may be used.

Specific examples of such radiation-curable resins include acrylic acid, methacrylic acid, or acrylic double bonds such as ester compounds thereof, and diallylphthalate, which exhibits an unsaturated double bond that has radical polymerizability. It is a thermoplastic resin in which groups that can be crosslinked or polymerized by radiation irradiation, such as allylic double bonds and unsaturated bonds such as maleic acid and maleic acid derivatives, are contained or introduced into the molecule of the thermoplastic resin.

Examples of thermoplastic resins that can be modified into radiation-curable resins include vinyl chloride copolymers, saturated polyvinyl sulfate resins,
Examples include polyvinyl alcohol resins, epoxy resins, phenoxy resins, cellulose derivatives, and the like.

Other resins that can be used for radiation sensitivity modification include polyfunctional polyester resins, polyether ester resins, polyvinylpyrrolidone resins, and derivatives (pvp
Also effective are acrylic resins containing at least one of olefin copolymers), polyamide resins, polyimide resins, phenol resins, spiroacetal resins, hydroxyl group-containing acrylic esters, and methacrylic esters as polymerization components.

The thickness of the protective film 6 made of such a radiation-curable compound is 0.
It is 1 to 30 μm, more preferably 1 to 1'0 μm.

If the film thickness is less than 0.1 μm, it will not be possible to form a uniform film, and the moisture-proofing effect will not be sufficient in a humid atmosphere.
The durability of the magnetic thin film layer 4 does not improve, and the thickness of 30 μm
If it exceeds this value, the recording medium will warp and the protective film will crack due to shrinkage during curing of the resin film, making it impractical for practical use.

Such a coating film may usually be formed by combining various known methods such as spinner coating, gravure coating, spray coating, and dipping. The conditions for forming the coating film at this time may be appropriately determined in consideration of the viscosity of the mixture of coating film composition, the intended coating thickness, etc.

In order to cure such a coating film to form a protective layer, the coating film may be irradiated with radiation such as electron beams or ultraviolet rays.

When using an electron beam, the radiation characteristics include acceleration voltage 1
It is convenient to use a radiation accelerator of 0.00 to 750 KV, preferably 150 to 300 KV, and to irradiate at an absorbed dose of 0.5 to 20 Megarad.

On the other hand, when ultraviolet rays are used, a photopolymerizable sensitizer is usually added to the radiation-curable compound as described above.

The photopolymerization sensitizer may be a conventionally known one, such as benzoin type sensitizers such as benzoin methyl ether, benzoin ethyl ether, α-methylbenzoin, α-chlordeoxybenzoin, benzophenone, acetophenone, bisdialkylaminobenzophenone, etc. Examples include ketones, quinones such as acedraquinone and phenanthraquinone, and sulfides such as benzyl disulfide and tetramethylthiuram monosulfide.
The photopolymerization sensitizer is 0.1 to 10% by weight based on the resin solid content.
A range of is desirable.

In order to cure a coating film containing such a photopolymerizable sensitizer and a radiation-curable compound using ultraviolet rays, various known methods may be used.

For example, an ultraviolet light bulb such as a xenon discharge tube or a hydrogen discharge tube may be used.

A protective plate is usually provided on the protective film 19 with an adhesive layer interposed therebetween.

That is, this protection plate is used only in the case of so-called single-sided recording, in which recording and reproduction are performed only from the back side (the side on which the magnetic thin film layer 14 is not provided) of the substrate 11.

The resin material of such a protective plate is not required to be particularly transparent, and various resins such as polyethylene,
Polyvinyl chloride, polystyrene, polypropylene, polyvinyl alcohol, methacrylic resin, polyamide, polyvinylidene chloride, polycarbonate, polyacetal,
Various thermoplastic resins such as fluororesin, phenol resin, urea resin, unsaturated polyester resin, polyurethane, alkyd resin, melamine resin, epoxy resin, silicone resin, etc. can be used.

Note that various inorganic materials such as glass and ceramics may be used as the protective plate.

The shape, dimensions, etc. of this material are substantially the same as those of the substrate 11 described above.

Such a protection plate is bonded via an adhesive layer as described above. The adhesive layer is usually an adhesive such as hot melt resin, and has a thickness of about 1 to 100 μm.

On the other hand, instead of using the protective plate described in -F, the above magnetic thin film layer 14.1 protective layer 16. A so-called double-sided recording method uses another set of substrates having a protective film 19, etc., faces each other with the ceramic thin film layer inside, and bonds them together using an adhesive layer, so that writing is performed from the back side of both boards. It can also be used as a type.

Further, it is preferable to provide a hard coat layer as various protective films on the back surface (the surface on which the magnetic thin film layer 14 is not provided) of the substrate 11 and the protective plate.

The material of the hard coat layer may be the same as that of the protective film 19 described above.

■Specific effects of the invention According to the present invention, the substrate 1 has a plasma polymerized film base layer, an intermediate layer is provided on the plasma polymerized film base layer, and a recording layer is provided on the intermediate layer. A plasma polymerized film having a protective layer directly or via a protective layer on the recording layer, and these plasma polymerized films are made by polymerizing organic compound monomers having a carbonyl group. Moreover, since the refractive index of this plasma polymerized film in 6328 people is 1.3 to 1.7, an optical recording medium with excellent coin resistance and adhesive properties can be obtained.

In particular, when an intermediate layer, protective layer, etc. made of a material such as glass is provided in contact with this, the adhesion becomes strong.

(2) JL-based embodiments of the invention The present invention will be explained in further detail by showing JL-based embodiments of the present invention.

Example 1 A substrate 11 made of bisphenol A-based polycarbonate resin (molecular m15000) with a diameter of 13 cm and a thickness of 1.2 mm was placed in a vacuum chamber and heated to 10-5 Torr.
After drawing a vacuum, A' was used as the processing gas, and the flow rate was:
Plasma was generated by applying a high frequency voltage of 13.56 MHz while maintaining the gas pressure at 0.1 Torr at 50 mJZ/min, and the surface of the substrate 11 was plasma-treated.

After that, the plasma polymerized film F layer 1 was further prepared under the conditions described in f.
2 was formed on the substrate 11.

In addition, the abbreviations in the table indicate the following.

M M A-... Methyl methacrylate, MA...
Methyl acrylate, AA...-acrylic acid, ME...methyl ethyl ketone TFE-...tetrafluoroethylene, VC...
Vinyl chloride, VDC...-vinylidene chloride The refractive index n of these plasma polymerized films was measured by 6328 people.

Further, elemental analysis of these plasma polymerized films was measured by SIMS, and film thickness was measured by an ellipsometer.

Furthermore, the presence of C=O groups in the plasma polymerized film was confirmed by FTIR measurement.

The plasma polymerized crotch base layer 12 thus formed is coated with glass (Si0248wt%).

A (120315wt%, BzO*
14wt%.

Na2O3wt,%, 202wj,%, BaO5wt
%, Ca09 wt%, Mg04 wt%) to a thickness of 900 mm by high frequency magnetron sputtering.

On this intermediate layer 15, 21 at% Tb and 68 at% F
A 7at%Co, 4aL%Cr alloy thin film was deposited to a thickness of 800 mm by sputtering to form a magnetic thin film layer 14.
And so.

In addition, the target is Tb, Co, and C on the Fe target.
The one with the r chip on it was used.

Glass (same as in the case of the intermediate layer) is placed on this magnetic thin film layer 14.
A protective layer 16 with a thickness of 1000 mm was formed by sputtering, and a coating composition containing the following radiation-curable compound was formed as a protective film 19 on this protective layer 16 by spinner coating.

(Coating Composition) 100 parts by weight of polyfunctional oligoester acrylate 5 parts by weight of photosensitizer After the coating composition was formed, it was crosslinked and cured by irradiation with ultraviolet rays for 15 seconds to obtain a cured film.

The film thickness at this time was 5-.

Incidentally, the same treatment was also performed on the back surface (2) of the substrate 11 described above. Furthermore, a protective plate made of polycarbonate resin and having a diameter of 13 cm was adhered onto the protective layer film 19 using an adhesive.

In this way, various magneto-optical disks shown in Table 1 were produced, and the following characteristic values were measured for these samples.

(1) C/N ratio (deterioration on storage) The initial C/N ratio and the change (deterioration) in the C/N ratio after storage for 1000 hours at 60° C. and 90% RH were measured under the following conditions.

Rotation speed 4 m/sec Carrier frequency 500 to Hz resolution
30Hz recording power (830nm)
3-4mW reproduction power (830nm)
1 mW (2) Pit error rate The pit error rate of the EFM signal was measured at the initial stage and after storage for 1000 hours at 60° C. and 90% RH.

(3) Adhesive strength Adhesive tape is adhered to the surface of the protective film 19 of the prepared magneto-optical disk with a constant pressure.
The force required to separate the substrate from the sputtered laminate (intermediate layer, magnetic thin film layer, protective layer, protective film) was measured by separating the substrate at a constant speed in the angular direction.

The adhesive strength value W of each sample was expressed as the improvement rate (%) shown below with respect to the adhesive strength value W0 of Sample No. 11 (blank). This is the initial improvement rate.

The improvement rate (%) after storage for 1000 hours at 60° C. and 90% RH was also determined in the same manner.

Example 2 Example! In Sample 1, a plasma polymerized film protective layer 17 is roughly formed on the protective layer 16F, and a protective fi
A magneto-optical disk was prepared in the same manner as Sample 1. In this case, the polymer film used as the protective layer 17 is the plasma polymer film 1 similarly to the base layer 12. This is called sample A.

Regarding this sample A, the C/N ratio and pit error rate were measured in the same manner as in Example 1.

However, the storage time was 2000 hours. The results are shown below.

Incidentally, such an effect is caused by the phase transition type Te −G e
, T e OX, T e -S e, etc. were similarly realized.

The effects of the present invention are clear from the above examples.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing one embodiment of a magneto-optical recording medium, each showing an example of the present invention. FIG. 3 is a schematic diagram of a plasma polymerization apparatus. Explanation of symbols 1--Magneto-optical recording medium, 11--substrate, 12--plasma polymerized film underlayer, 14--magnetic thin film layer, 15--intermediate layer, 16--protective layer, 17--plasma polymerized film protective layer 19 -Protective film, 53-Mixer, 54-・Direct current,
AC and variable frequency power supply, 56-oil rotary pump, 57--liquid nitrogen trap, 58--oil diffusion pump, 59--vacuum controller. 111.--Substrate to be processed, 511.512.--Source gas source, 521.522--Mass flow controller, 551.
552-electrode

Claims (4)

[Claims] (1) An optical recording medium having a plasma polymerized film base layer on a substrate, an intermediate layer on the plasma polymerized film base layer, and a recording layer on the intermediate layer, The membrane is made by polymerizing an organic compound monomer having a carbonyl group, and the 6328 of this plasma polymerized membrane is
An optical recording medium having a refractive index in Å of 1.3 to 1.7. (2) The thickness of the plasma polymerized film base layer is 10 to 1000 Å
An optical recording medium according to claim 1. (3) Having a plasma polymerized film base layer on the substrate, having an intermediate layer on this plasma polymerized film base layer, having a recording layer on this intermediate layer, and directly or directly on this recording layer. An optical recording medium in which a plasma-polymerized film protective layer is formed with a protective layer interposed therebetween, wherein the plasma-polymerized film is obtained by polymerizing an organic compound monomer having a carbonyl group, and the plasma-polymerized film has a refractive index at 6328 Å. is 1.3 to 1.
7. An optical recording medium characterized in that: (4) The optical recording medium according to claim 3, wherein the plasma polymerized film base layer and the plasma polymerized film protective layer each have a thickness of 10 to 1000 Å.