JPH03183039A - Optical disc and its manufacturing method - Google Patents

Abstract

PURPOSE:To improve the weatherability of recording layers by extending ceramics layers to the inner side and outer side of reflecting layers and the recording layers. CONSTITUTION:Protective layers 2, 10, the recording layers 3, 11, and the protective layers 4, 12 are successively formed on substrates 1, 9. The reflecting layers 5, 13 are provided in the region on the side outer than center holes 16 on the layers 4, 12 and the side inner than the outside diameter of the substrates 1, 9. The ceramics layers 6, 14 consisting of SiAlNO, etc., are then formed on the side inner than the inside diameter of the reflecting layers 5, 13 and the recording layers 3, 11 and the side outer than the outside diameter thereof. The substrates are thereafter stuck to each other via an adhesive layer 7. Thus, the weatherability of the recording layers is improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical disc and a method for manufacturing the same.

[Conventional technology]

In the structure of a conventional optical disk, the side surface of the recording layer is not covered with a ceramic protective film or a metal reflective film, as in Japanese Patent Laid-Open No. 63-94140. Also, USP4,731,62
As in No. 0, the adhesive layer made of ultraviolet curable resin is limited to the area where the recording layer is not formed. Furthermore, USP4,731
, 620, the adhesive layer made of thermosetting resin is directly bonded to the substrate in the outer peripheral area of the substrate.

On the other hand, conventional optical disc manufacturing methods only use either ultraviolet curing or heat curing.

[Problem to be solved by the invention]

However, the structure of the optical disk described above has the following disadvantages: (1) Adhesion strength is low at the inner and outer peripheral portions of the substrate; and (2) the side surfaces of the recording layer are susceptible to deterioration.

Furthermore, the above-mentioned optical disk manufacturing method has the following disadvantages: (1) the substrate is laid flat during the heat curing process, which tends to cause distortion of the board; and (2) the adhesive protrudes onto the sides of the substrate during the adhesive curing process.

Therefore, the present invention aims to solve these problems.
The purpose of this is to improve the weather resistance of the recording layer, the second purpose is to enable vertical placement of the substrate during the thermosetting process, and the third purpose is to improve the adhesion during the thermosetting process, etc. The purpose is to prevent the agent from spilling out.

[Means to solve the problem]

The optical disc of the present invention includes (1) a first substrate, a second substrate, and an adhesive layer for bonding the first substrate and the second substrate together, the optical disc comprising: a first substrate extending above the substrate; a first protective layer, a recording layer provided on the first protective layer, and a second protective layer extending over the recording film.
a protective layer extending over the second protective layer and provided in a region outside a center hole provided in the substrate and inside an outer diameter of the substrate; a ceramic layer extending over the layer and extending in an area surrounded by a diameter smaller than the inner diameter of the reflective layer and the recording layer and a diameter larger than the outer diameter of the reflective layer and the recording layer; Features.

(2) An optical disc having a first substrate, a second substrate, and an adhesive layer for bonding the first substrate and the second substrate, wherein the adhesive layer is made of a thermosetting resin and an ultraviolet curable resin. Particular feature (3) characterized in that the substrate comprises a first protective layer extending on the substrate, a recording layer provided on the first protective layer, and a recording layer extending on the recording film. a reflective layer extending over the second protective layer and provided in a region outside the center hole and inside the outer diameter of the substrate; do.

(4) The recording layer is made of a rare earth-transition metal alloy.

(5) A recording layer is formed on one of the first substrate and the second substrate.

Further, the method for manufacturing an optical disk of the present invention includes (6) a first substrate, a second substrate, and an adhesive layer for bonding the first substrate and the second substrate, and a thin film is formed on the substrate. and bonding the first substrate and the second substrate, wherein the first substrate or the second substrate includes a thermosetting resin and an ultraviolet curable a step of applying an adhesive made of resin, a step of bonding the first substrate and the second substrate, a step of irradiating ultraviolet rays to the bonded substrates, and a step of bonding after the step of irradiating ultraviolet rays. The method is characterized by comprising a step of heating the substrate.

(7) The step of forming a thin film on a substrate includes a step of forming a first protective layer extending on the substrate, a step of forming a recording layer on the first protective layer, and a step of forming a recording layer on the first protective layer. forming a second protective layer extending over the film; forming a second protective layer extending over the second protective layer outside a center hole provided in the substrate and inside an outer diameter of the substrate; forming a reflective layer in a region extending above the reflective layer and inside the inner diameter of the reflective layer and the recording layer and outside the outer diameter of the reflective layer and the recording layer; The method is characterized by comprising a step of forming a ceramic layer.

(8) The recording layer is made of a rare earth-transition metal alloy.

(9) A recording layer is formed on one of the first substrate and the second substrate.

〔Example〕

[Example 1] The present invention will be explained in detail below based on the drawings.

FIG. 1 is a schematic diagram of an optical disc according to the present invention. 1 and 9 are polycarbonate substrates, 2 and 10 are Si
First protective layer of AgN, 3 and 11 are NdDyFeC
o recording layer, 4 and 12 are 5iAj7N second protective layers, 5 and 13 are Ag layers, 6 and 14 are SiA, Q
Layer O layer, 7 is an adhesive layer, 8 and 15 are hard coat layers,
16 is a center hole.

Polycarbonate substrates 1- and 9 were formed by injection compression molding. A mask jig was attached to the inner and outer peripheries of the polycarbonate substrates Nos. 1 and 9 to prevent the recording layer and reflective layer from turning, and the SiAgNo layer, NdDyFeCo
A layer, a 5tAj7N layer, and an Ag layer were successively formed in this order. The first protective layer of 5iAIN in Nos. 2 and 10 was formed by RF reaction magnetron sputtering using a mixed gas of nitrogen and argon using a sintered target of 5iAJ7. 3 and 11 NdDyFeC
The recording layer o was formed by DC magnetron sputtering using a NdDyFeCo alloy target. Similar to the first protective layer of SiAgN in Nos. 2 and 10, the second protective layer of 5iApN in Nos. 4 and 12 was formed by the RF reaction magnetron sputtering method by introducing a mixed gas of nitrogen and argon. . The A and Q layers of Nos. 5 and 13 were formed by DC magnetron sputtering using an AN target and introducing argon gas. 6 and 14SiAIN
The layer was formed by RF reaction magnetron sputtering using a mixed gas of nitrogen, oxygen, and argon using a SiAg alloy target. 5 or 1
After forming the Ag layer No. 3, the vacuum system was once leaked, and the mask jig covering the inner and outer peripheries of the disk was removed, and the film was formed. The adhesive layer for No. 7 is Epicron S-129 from Dainippon Ink and Chemicals and Ebicure IB from Yuka Shell Epoxy.
A mixture of MI-12, 1,6-hexane diol diacrylate, t-butylperoxyisobutyrate, and Irgacure 907 manufactured by Ciba Geigy was applied in a ring shape to the side on which the recording layer was formed. After that, it was combined with another substrate in a vacuum system, and the bonded substrate was placed on a hot plate and heated to spread the adhesive. After the adhesive was evenly spread, UV rays were irradiated with a metal/helide lamp to cure the UV curable adhesive in the areas where the recording layer was not formed, and then heated at 50°C for 3 hours and 60°C for 8 hours. The adhesive layer was cured by heating. 8 and 15 l\-
The coat layer is made by spin-coating a mixture of trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, and Irgacure 907 manufactured by Ciba Geigy on the substrate surface, and then curing it by irradiating ultraviolet rays with a high-pressure mercury lamp. .

Next, Table 1 shows the properties of optical discs produced using the conventional method for bonding optical discs according to the present invention when subjected to a weather resistance test.

The comparative example in the table, which was bonded using an epoxy adhesive, had the structure shown in Figure 1 without the ceramic layer above the reflective layer, and everything else was created using the same structure and manufacturing method. be. The roll coat of the comparative example is one in which a hot melt adhesive is applied and bonded together by a roll coat method.

As is clear from the results in Table 1, it can be seen that the optical disc and the method for manufacturing the same according to the present invention result in an optical disc with long-term reliability that does not change even when left under high temperature and high humidity for a long time.

In addition to these embodiments, the present invention can achieve similar effects in the following embodiments.

For example, in Example 1, the ceramic layer on the AI reflective layer is a 5iAfINO layer, but these are S
Oxynitride such as 1A1t BNO, S i/l PNOSS fPO, SiN, AρN18N, StA
ρNSS iAgPNSS i/l In addition to nitrides such as BN, A i) Os S 10- M g Oz B
Almost all ceramics, whether transparent or opaque, such as oxides such as eO, other fluorides, and carbide silicides, can be used.

In addition, in Example 1, the first protective layer, the recording layer, the second protective layer, and the reflective layer are formed on the substrate in this order, and the recording layer is not formed on the outer circumference and inner circumference of the substrate. However, a structure in which a ceramic layer is formed on a structure in which a recording layer is sandwiched between protective layers, that is, a structure without a reflective layer may also be used.

Further, the first and second protective layers may be larger than the recording layer and the reflective layer, and may cover the entire surface of the substrate, for example.

In addition to polycarbonate resin, the substrate material may be acrylic resin, styrene resin, polyester resin, polyimide resin, or polymer resin thereof.

[Example 2] The structure of an optical disc is shown in FIG.

For the epoxy used in the adhesive layer, Evicron S-129 manufactured by Dainippon Ink and Chemicals was used as the main agent, and BMI-12 manufactured by Yuka Shell Epoxy Co., Ltd. was used as the curing agent. The blending ratio of the main agent and curing agent was 20:1 by weight. The photocurable resin has a weight ratio of 20% trimethylolpropane triacrylate.
and 1,6-hexanediol diacrylate to which 1 portion of Irgacure 907 from Ciba Geigy, 0.3 portions of KAYARAD DETX from Nippon Kayaku, and 1 portion of dicumyl peroxide were added. The blending ratio of epoxy resin and photocurable resin is epoxy resin 70% by weight.
In contrast, the photocurable resin 30 is used.

Next, Table 2 shows the results of 80% when the optical information recording medium having the structure shown in FIG.
The values obtained by normalizing the pit error rate after a 3000-hour weathering test at 90% RH with the pit error rate before the weathering test and the properties at that time are shown.

The method for manufacturing the optical disc is shown below. After forming a film by 800 people by RF reaction magnetron sputtering using a 5LAj7 sintered target on the grooved side of a polycarbonate substrate on which spiral tracking grooves were formed at a pitch of 1.6μ by injection compression molding, NdDyF
A 900A film was formed by DC magnetron sputtering using an eCo alloy target, and then a 5iA film was deposited on top of it.
Two films were formed by 800 people using an RF reaction magnetron sputtering method using an alloy target of I, and were bonded together using various adhesives. The bonding method, other than the roll coating method, is to apply an adhesive in a donut shape to the side where the recording layer part of the substrate is formed, then degas it in a vacuum system, and then bond it to another substrate in a vacuum system. At the same time, align the center holes of the upper and lower substrates, and use an ultra-high pressure mercury lamp to irradiate the adhesive with a power of 80 mW/(7) for 15 seconds to cure the ultraviolet adhesive, and then heat it at 60°C for 5 hours. The thermosetting adhesive was temporarily cured by heating and then cured by heating at 100° C. for 2 hours.

Epicuron S-129 Epicuron 830 Epicuron 830-S Epicuron 855 Epicuron 520 Epicort 807 Epicort 802 Epicort 815 Evicure IBMI-1, 2 Evicure BMI-12 Evicure EMT-24 KAYARAD IIDDA KAYARAD TMPT A KAYARAD DPIIA KAYARAD DPCA-6O NK ester ・TMPT NK ester HD Irgacure 651 Dainippon Ink Chemicals Yuka Shell Epoxy Nippon Kayaku Shin Nakamura Chemical Ciba Geigy Irgacure 907 Ciba Geigy Grocure 11 (6 Merck KAYACURE BIBE Nippon Kayaku K
AYACURE DETX As can be seen from Table 2, the optical disc of the present invention is heated at 80°C and 90% R.
Since the pit error rate does not change even under the condition of H, it can be seen that there is long-term reliability.

Note that the present invention is not limited to Example 2; for example, an NdDyFeCo layer was used as the recording layer;
yTbFeCo layer, GdTbFeCo layer, TbFeCo
In addition to the magneto-optical recording layer such as Te-TeOx layer, In-A
There is no problem in using a recording layer of an optical layer change type such as a g layer. Further, as for the protective layer, in addition to the 5iADN layer, a SiN layer, a Si0 layer, an AJ7N layer, etc. may be used. Further, in this embodiment, a double-sided optical recording medium is taken as an example, but a single-sided optical recording medium may be used, for example, in which a substrate on which a recording layer is formed and a substrate without a recording layer are bonded together.

In the present invention, the adhesive is mainly a combination of only a base agent and a curing agent, but reactive diluents, curing accelerators, fillers, silane coupling agents, and leveling agents are used to the extent that the physical properties of the cured product do not change much. , stabilizers and other additives may be added.

When the adhesive is heated and cured, the substrate may become distorted depending on how it is placed. When the board is placed horizontally, significant distortion occurs, but when it is placed vertically, almost no distortion occurs.

Furthermore, since the adhesive is cured with ultraviolet rays on the outer and inner circumferences of the substrate, the adhesive will not ooze out during the heat curing process.

It is easier to work with epoxy resins that have a viscosity of 5,000 cps or less at room temperature, such as bisphenol F or bisphenol A with a small amount of reactive diluent added, making it easier to bond and defoaming. It's easy. If the adhesive is laminated with a large amount of bubbles, the stress caused by the curing of the adhesive will adversely affect the signal and reduce reliability. Further, it is preferable to use an imidazole-based or cycloaliphatic amine-based epoxy curing agent such as menthanediamine from the viewpoint of heat resistance of the cured product and pot life of the adhesive. The amount added is 1% to 10% based on the base agent.
is appropriate. If it is less than 1%, it may take a long time to cure the adhesive, or the adhesive may be incompletely cured. If it exceeds 10%, the pot life of the adhesive becomes short, making it difficult to apply using a machine, and the heat resistance of the cured product decreases.

It is preferable to adjust the amount of addition and the components of the main agent so that the properties of the cured product can be maintained and the pot life is 5 hours or more. A curing agent that is liquid at room temperature is easier to mix with the main agent, so it is preferable to mix a curing agent that is solid at room temperature with a curing agent that is liquid at room temperature.

In addition, the photocurable resin used in the present invention should have high reactivity and low viscosity at room temperature, so the main component of the photocurable resin is preferably an acrylate monomer or oligomer, such as hexanediol diol. One type or a mixture of two or more types selected from acrylate, neopentyl glycol diacrylate, butanediol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol tri(tetra)acrylate, dipentaerythritol hexaacrylate, etc. It is recommended to use Hardening agent is 300
It is necessary to use a material that has absorption at wavelengths longer than nm, and an example of this is Merck's Darocure-1116,2.
273 and Ciba Geigy's Irgacure 651.90
7, benzoin isopropyl ether, benzoin isobutyl ether, or the like. Further, in the case of a double-sided medium that requires curing even in areas not exposed to light, a peroxide such as dicumyl peroxide or benzoyl peroxide may be added to impart thermosetting properties to the photocurable properties.

Additionally, small amounts of sensitizers, such as diethylthioxant,
It is also good to add anthracene, isoprobylthioxanthone, etc.

[Example 3] The structure shown in FIG. 1 was used as the structure of the optical disc.

The hard coat layer contains 30% dipentaerythritol hexaacrylate, 30% 16-hexanediol diacrylate, 35% urethane acrylate, 3% benzyl dimethyl ketal, 2% γ-glycidoxypropyl trimethoxysilane, and sodium dialkyl sulfosuccinate. 11
After applying a 00 pp mixture onto one side of a substrate by a spin code method, it was cured by irradiating light with a high-pressure mercury lamp.

Next, the adhesive will be explained. () indicates parts by weight at the time of blending. As the compound having an epoxy ring and a (meth)acryloyl group, a mixture (30) of bisphenol F having an acryloyl group on one side and an epoxy ring on the other side, and bisphenol F having an epoxy ring on both sides was used. 2-ethyl-4-methylimidazole (2) was used as an epoxy polymerization initiator.

Irgacure 907 (1) manufactured by Ciba Geigy was used as a photopolymerization initiator. T-butylperoxy-2-ethylhexanoate (1) was used as the organic peroxide. In addition, γ-glycidoxypropyltrimethoxysilane (1) was used as a silane coupling agent. The bonding was carried out as follows. After applying adhesive in a ring shape to the side of the optical disc where the recording layer is formed,
Paste it with another optical disc in a vacuum system, take it out, heat the disc with a far-infrared lamp, and spread the adhesive.
The disks were temporarily fixed by irradiating them with ultraviolet rays, and heated at 60° C. for 5 hours to harden the adhesive in the areas where light did not pass through.

Next, Table 1 shows the results of a weather resistance test at 70° C. and 90% RH when optical disks having the structure shown in FIG. 1 were bonded together using different adhesives. As is clear from the results in Table 1, the optical disks bonded using the adhesive of the present invention have excellent weather resistance and long-term reliability.

Table Bis A-EP-AC: Compound with epichlorohydrin and acrylic acid added to bisphenol A Bis A-EP-EP: Compound with epichlorohydrin added to both sides of bisphenol A Bis F-EP-AC: Bisphenol F with epichlorohydrin and acrylic acid Bis I-EP-EP: A compound in which epichlorohydrin is added to both sides of bisphenol F. Bis-F-AC-AC: A compound in which acrylic acid is added to both sides of bisphenol F. H-EP-AC: A compound in which epichlorohydrin and epichlorohydrin are added to hexanediol. Compounds with added acrylic acid Perbutyl O: Valloyl 355 manufactured by NOF Corporation: Irgacure 907 manufactured by NOF Corporation: Irgacure 6 manufactured by Ciba Geigy Co., Ltd.
51: 〃 Darocure 2273: Merck Darocure 1164: // IBM! -12: Ebicure IB oil-based shell epoxy
MI-12 8MI-12: 〃 Ebicure BM
I-12 In the present invention, when a compound having at least an epoxy ring and a (meth)acryloyl group or a methacryloyl group is used as the adhesive, it can be cured by light irradiation and can also be cured by heat. If the adhesive only has a heat curing property, when the adhesive is pasted together and heated, the viscosity decreases before it hardens and it overflows from the edges, resulting in poor workability. Therefore, it is necessary to temporarily fix the adhesive using a method other than heat. In the present invention, the disk can be temporarily fixed by irradiating the adhesive layer with light so that the adhesive layer extends to the portion where the recording layer is not bent, and therefore, the workability is good. There is no problem because the adhesive in the portion where the recording layer is occluded through which light does not pass can be cured by heat. As described above, it can be seen that the adhesive of the present invention is suitable for use in temporarily fixing with light and curing with heat.

Note that the present invention should not be considered limited to these examples; for example, in the present invention, the recording layer is made of NdDyFe.
Although the Co magneto-optical recording layer has been described, TbFeCoS
In addition to DgTbFeCo, GdTbFe, etc., Te-T
A system using a light phase change type such as e0xSTe InSb or InAg or an organic dye such as cyanine can also be applied. In addition to the 5iAINO layer, the protective layer also includes a SiN layer, an AgN layer, and an S layer.
An iO layer composite oxide, composite oxynitride, etc. may also be used. The structure is not limited to one in which the recording layer is sandwiched between protective layers, but may also be one in which the recording layer is directly formed on the substrate, or a structure in which a reflective layer is formed on the substrate as in the case of a compact disc.

In addition to the adhesive shown in this example, compounds having multiple epoxy rings or multiple acrylate groups may be used, and acrylates such as trimethylolpropane triacrylate, neopentyl glycol diacrylate, dipentaerythritol In addition to polyfunctional acrylates such as hexaacrylate, monofunctional acrylates may also be used. Considering workability, any organic peroxide may be used as long as it has a decomposition temperature between room temperature and about 80°C. Considering workability, the silane coupling agent also has a relatively low vapor pressure and a temperature of 80°C.
Any material that can be reacted with below may be used.

As an example of a compound having an epoxy ring and a (meth)acryloyl group used in the present invention, if the proportion of the epoxy ring is larger than the proportion of the acryloyl group or methacryloyl group, the curing shrinkage rate, heat resistance, adhesion strength, etc. of the adhesive will be improved. Excellent in terms of points. More preferably, the ratio of the epoxy ring to the acryloyl group or methacryloyl group is from 90:10 to 70:30.
It is better to be in between.

Epoxy hardeners include acids, amines, and amides, but it is better to change them depending on the purpose of use. For example, if relatively transparency is required, use acid-based hardeners, and if you want to harden at low temperatures, use amines. If you want to harden at room temperature, it is best to use aliphatic or aromatic amines.Liquid hardeners are easier to work with, so solids can be liquefied by mixing them with liquid hardeners. It is recommended to use it.

Examples of compounds having an epoxy ring and (meth)acryloyl group that can be used in the present invention include epoxy rings and (meth)acryloyl groups on both sides of bisphenol A and bisphenol F.
Examples include aromatic compounds having an acryloyl group, and aliphatic compounds having an epoxy ring or (meth)acryloyl group on both sides of hexanediol or butanediol. Examples of epoxy polymerization initiators include aliphatic polyamines, polyamide resins, tertiary amines,
There are amine salts, etc., and high temperature curing types include aromatic diamines, acid anhydrides, and Lewis acid complex compounds. There are also other imidazoles.

[Example 4] Hereinafter, the manufacturing method of the present invention will be explained in detail based on the drawings.

FIGS. 2(a) to 2(f) are schematic diagrams for explaining the method of manufacturing an optical disc according to the present invention. Figure 2 (
a) indicates an optical disk; 21 is a portion on the outer periphery of the substrate where the recording layer is not formed; 22 is a portion on the inner periphery of the substrate where the recording layer is not formed; and 23 is the center hole portion of the disk. FIG. 2(b) shows the adhesive being applied using 24 dispensers. FIG. 2(C) is a diagram showing a substrate coated with an adhesive and another substrate being bonded together, and 25 is an adhesive layer coated in a ring shape. FIG. 2(d) is a diagram showing the adhesive of the disks bonded together in FIG. 2(c) being spread by a heater 26. Second
Figure (e) shows 28 lamps using 27 metal halide lamps.
FIG. 3 is a diagram showing how the adhesive at portions 21 and 22 is cured by irradiating ultraviolet rays. Figure 2 (f) is shown in Figure 2 (
The adhesive layer other than the portions 21 and 22 that were not cured in step e) is cured by heat, and two of them are open. This step proceeds in the order of (a) to (f).

FIG. 3 is a basic configuration diagram of the optical disc according to the present invention,
30 and 36 are polycarbonate substrates, 31 and 37
is a SiAgN layer, 32 and 38 are TbFeCo layers, 33
and 3 are 5iApN layers, 34 and 40 are A and Q layers, 3
5 is an adhesive layer, and 41 and 42 are hard coat layers. 3
0 and 36 polycarbonate substrates were formed by injection compression molding. 31 and 37 SiA, 9N layers are Si
The films were formed using the sintered targets A and Q by RF reaction magnetron sputtering using a mixed gas of nitrogen and argon. 32 and 38 Tb
The FeCo layer was formed using a TbFeCo alloy target.
The film was formed by C magnetron sputtering. 33 and three 5i AIIN layers are 31 and 37 5t
Like the Aj7N layer, this film was formed by the RF reaction magnetron sputtering method by introducing a mixed gas of nitrogen and argon. The 11 layers 34 and 40 were formed by DC magnetron sputtering using an AI target and introducing argon gas. The adhesive layer of 35 is Dainippon Ink &Chemicals' Ebicuron S-129 and Yuka Shell Epoxy's Ebicure IBM.
After applying a mixture of I-12, 1,6-hexanediol diacrylate, t-butylperoxyisobutyrate, and Irgacure 907 manufactured by Ciba Geigy in a ring shape to the side on which the recording layer was formed, vacuum Combine the bonded substrate with another substrate within the system, place the bonded substrate on a hot plate, heat it to spread the adhesive, and irradiate it with ultraviolet light using a metal halide lamp to bond the areas where the recording layer is not formed. The agent was temporarily cured, and then the adhesive layer was cured by heating at 50°C for 3 hours and 60°C for 8 hours. For the hard coat layers 41 and 42, a mixture of trimethylolpropane triacrylate, 16-hexanediol diacrylate, and Ciba Geigy's Irgacure 907 was spin-coded onto the substrate surface, and then cured by irradiating ultraviolet rays with a high-pressure mercury lamp. It is something.

Next, an example of creating an optical disc using a conventional method will be described. Optical discs bonded together using the roll coating method are
When a weather resistance test was conducted at 70° C. and 90% RH for 1000 hours, the recording layer was oxidized and the pit error rate increased. The optical disc of the present invention was tested at the same time, but there was no change in pit error rate. Optical disks laminated using a normal epoxy resin had a high viscosity at the time of lamination, so the adhesive layer was thicker, and the amount of surface runout was larger than that of the optical disk according to the present invention. The maximum resistance was 7 milliradians using ordinary epoxy resin, and the maximum 2 milliradians for optical discs. Furthermore, in optical discs bonded together using ordinary epoxy resin, the adhesive overflowed from the outer periphery of the disc when it cured, spoiling the appearance of the optical disc. Temperature control is difficult with adhesives that cure with heat, and it is necessary to ensure that the substrate does not move while the adhesive layer is curing.If the adhesive is bonded with an adhesive that cures at room temperature, stress will be applied to the recording layer when the adhesive layer hardens. The envelope of the playback signal was disturbed and errors increased. As described above, optical discs manufactured by conventional methods have problems such as poor weather resistance, difficult manufacturing methods, and low yields. However, it can be seen that the present invention provides an optical disc that is highly reliable and easy to produce without the problems that have conventionally occurred.

In Example 4, it is preferable to use a mixture of at least an epoxy main ingredient and a curing agent, an ultraviolet curing resin main ingredient and a curing agent, and an organic peroxide added thereto.

Examples of the main epoxy agent include bisphenol A, bisphenol F, novolac, and the like, with or without the addition of a reactive diluent, which is a low-viscosity epoxy. If the content of the reactive diluent increases, the viscosity of the adhesive will decrease and workability will improve, but the heat resistance and reactivity of the adhesive will decrease and the properties of the adhesive layer will deteriorate, so the amount added should be limited. It is better to

Epoxy curing agents include acid anhydrides, aromatic amines, aliphatic amines, amides, etc. Among them, those with a pot life of 1 to 50 hours at room temperature are best used.
It is preferable to select a curing agent that can be cured at a temperature of 80°C to 80°C. Examples include 2-ethyl-4-methylimidazole,
Examples include imidazole series such as 1-benzyl-2-methylimidazole and 1-isobutyl-2-methylimidazole, and cycloaliphatic amines such as menthanediamine.

It is best to use a base resin for UV curing resin that has a relatively low viscosity at room temperature and is highly reactive.
Examples include 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, neopentyl glycol diacrylate, dipentaerythritol hexaacrylate, and trimethylolpropane diacrylate, so it is best to use these as the main ingredients. .

As an example of the curing agent for the ultraviolet curable resin, one that absorbs at wavelengths longer than 3000 m is used. Examples include benzyl dimethyl ketal, 1-hydroxycyclohexylphenyl ketone, 2-methyl-[4-(methylthio)phenylcose-morpholino-1-propanone, benzoin, benzone ethyl ether, benzoin isobutyl ether, 1-( 4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one,
Examples include 3.3-dimethyl-4-methoxybenzophenone.

Preferred examples of organic peroxides include those that decompose within several hours when heated from 40°C to 70'C; examples include di-n-propyl peroxydicarbonate, di-myristyl peroxydicarbonate, and peroxyneohexanoate, di(2-ethoxyethyl)peroxydicarbonate, (di(methoxyisopropyl)peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, t-hexylperoxyneodecano) ate, 2,4-dichlorobenzoyl peroxide, t-hexyl peroxypivalate, t-butyl peroxypivalate, 3.5゜5-trimethylhexanoyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl Peroxide, cumyl peroxyoctoate, succinic acid peroxide, acetyl peroxide, t-butyl peroxy (2-ethylhexanoate), m-tolyl peroxide, benzoyl peroxide, t-butyl peroxyisobutyrate, 1.1-bis(t-butylperoxy)3,3.5
-trimethylcyclohexane, 11-bis(t-butylperoxy)cyclohexane, t-butylperoxymaleic acid, t-butylperoxylaurate, t-butylperoxy 3,5.5-trimethylhexanoate,
Cyclohexanone peroxide, t-butylperoxyallyl carbonate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl 2,5-di(benzoylperoxy)beef san, 2,2-bis(t-butylperoxy) ) octane, (-butylperoxyacetate, 2,2-bis(t-butylperoxy)butane, t
-butyl peroxybenzoate and the like.

In the present invention, the temperature at the time of bonding needs to be changed depending on the viscosity of the adhesive, and is preferably higher than room temperature, but is preferably 70° C. or lower in order to make it easier to obtain a constant temperature. More preferably it is 40°C to 60°C. The substrate heating for curing the adhesive is preferably from 40°C to 80°C, depending on the curing temperature of the adhesive. More preferably it is 50°C to 70°C.

In the present invention, as for the mixing ratio of epoxy and ultraviolet curing resin, the higher the mixing ratio of epoxy resin, the better the properties as an adhesive, and the ratio of epoxy and ultraviolet curing resin is 95% by weight.
;5 to 70:30 is preferred. Here, epoxy refers to an epoxy main ingredient and a curing agent, and an ultraviolet curable resin refers to an ultraviolet curable resin in which an organic peroxide is added to the main ingredient and a curing agent.

In the present invention, if the bonding is performed under reduced pressure, the adhesive can be easily degassed and air bubbles are difficult to be incorporated into the adhesive layer.

Furthermore, the adhesive layer will be explained. Ebicuron S-129 from Dainippon Ink and Chemicals is used as the main epoxy agent, and Ebicure B from Oil Shell Epoxy is used as the epoxy curing agent.
MI-12 was used, Ciba Geigy's Irgacure 261 was used as a photo or thermal cationic polymerization initiator, cumene hydroperoxide was used as an organic peroxide, and γ-glycidoxyprobyltrimethoxysilane was used as a silane coupling agent. The bonding method is 3 parts of BMI-12, 1 part of Irgacure 261, 1 part of cumene hydroperoxide,
A recording radius on the side where the recording layer of one disk is formed is prepared by mixing 7% by weight of a curing agent in which 2 γ-glycidoxypropyltrimethoxysilane is dissolved and 93% by weight of S-129. Apply it in a donut shape approximately in the center of the disc, attach it to the other disc in a vacuum system, leak the system and irradiate the disc with ultraviolet light while rotating the disc, temporarily fix the disc, and then heat the disc at 60°C for 50 minutes. It was cured by heating for a period of time. There are areas on the outer and inner peripheries where the recording layer is not formed so that the disc can be temporarily fixed using ultraviolet light.

Next, in Figure 1, when changing the adhesive layer,
The results of the 3000 hour weathering test at %RH are shown in Table 1.

As can be seen from the results in Table 1, the optical recording disk of the present invention shows no change in properties or pit error rate even after the weather resistance test, indicating that it has long-term reliability. In addition, it can be seen that this embodiment is suitable for mass production because the outer and inner circumferential portions of the disk can be temporarily fixed using ultraviolet rays.

Epicron S-129 Ebicuron 830-S Dainippon Ink & Chemicals, Ebicuron 520 Irgacure 261; Ciba Geigy Ebicoat 808 Yuka Shell Epixy Epicoat 807 Adekadol 5O-120; Asahi Denka Inc. However, the present invention is limited to these examples. This should not be considered as such, and various changes are possible without departing from the spirit of the invention. For example, in the present invention, a four-layer structure of a ceramic layer, a recording layer, a ceramic layer, and a metal layer is used on a PC board, but there is no problem with a structure in which a three-layer structure of a ceramic layer, a recording layer, and a ceramic layer is bonded together. It may be a single-sided structure in which a ceramic layer, a recording layer, and a ceramic layer are bonded to a PC board with only one ceramic layer or a PC board with no film formed, or the components of the adhesive layer. A system that does not contain an epoxy curing agent may also be used.

Further, as examples of the ceramic layer, in addition to SiA and QN layers, SiN layer, A47N layer, 5iAltNO layer, etc. may be used, and there is no problem even if the ceramic layers sandwiching the recording layer are made of different materials. In addition to the TbFeCo layer, the recording layer includes
In addition to magneto-optical recording layers such as a NdDyFeCo layer and a GdTbFe layer, a Te-TeOx layer, a phase change type such as Te5bAs, and one using an organic dye such as cyanine can also be used.

Depending on the type of recording layer, a ceramic layer may not be necessary.

Furthermore, in the present invention, an example was shown in which temporary fixing was performed using ultraviolet rays, but if an initiator that can be cured by heat is used, temporary fixing can also be done by heat, and curing can be performed using infrared rays, microwaves, high frequencies, etc. You can also do it.

In the present invention, the amount of silane or metal-based coupling agent added is 0.00% of the total weight of the adhesive. It was set from 5% to 8%, but 0
．． If it is less than 5%, the adhesion under high temperature and high humidity will be weak, resulting in poor reliability.On the other hand, if it is added more than 8%, weather resistance will be affected by the effects of alcohol, water, and other low molecular weight components caused by the decomposition of the coupling agent. tends to become worse. However, this does not mean that it should not be added less than 0.5% or more than 8%, but that it is appropriate to add between 0.5% and 8%. More preferably, the amount added is about 1% to 5%. In addition, in the present invention, organic peroxide is
．． It is added in an amount of 1 to 5% by weight, but if it is less than 0.1%, it takes time to cure the adhesive, and if it is more than 5%, the physical properties of the adhesive tend to deteriorate.

Again, this does not mean that it should not be added less than 0.1% or more than 5%, but that about 0.1% to 5% is appropriate. More preferably 0.5% to 3%
It is better to add

As the main epoxy agent, one with low viscosity is easy to work with, so use bisphenol F type, phenol novolac type, or bisphenol A type epoxy with a small amount of glycidyl ether, diglycidyl ether, etc. added as a reactive diluent. Good. Since this reactive diluent deteriorates the physical properties of the epoxy after hardening, it is better to limit the amount added, and it is better to keep it at 30% by weight or less.

Cycloaliphatic amines used as epoxy curing agents include 1-isobutyl-2-methylimidazole, 2-
Ethyl-4(5)-methylimidazole, 1-benzyl-2-methylimidazole, 2-methylimidazole,
Imidazole, 1-cyanoethyl-2-ethyl 4(5)
It is preferable to use one or a mixture of two or more selected from -methylimidazole, menthanediamine, N-aminomethylpiperazine, N-methylmorpholine, 1,3-diaminocyclohexane, isophoronediamine, and the like. Among them, menthanediamine and imidazole are preferably used in order to have a relatively long pot life when mixed with the epoxy main ingredient, and the appropriate amount of addition is about 2% to 7%. If it is less than 2%, the curing of the epoxy will be insufficient, and if it is more than 7%, the pot life will be shortened. More preferably 3% to 5% is appropriate.

Examples of coupling agents added to the adhesive in the present invention include γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(aminoethyl)aminopropylmethyldimethoxysilane, and γ-methacryloxypropyltrimethoxysilane. Methoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane,
γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltriacetoxysilane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, γ- Chloropropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, vinyltrichlorosilane, vinyltris(βmethoxyethoxy)
Silane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropylmethyljethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-phenyl-γ- Aminopropyltrimethoxysilane, Methyldichlorosilane, Phenyltrichlorosilane, Diphenyldichlorosilane, Tetramethoxysilane, Dimethyldimethoxysilane Phenyltrimethoxysilane, Diphenyldimethoxysilane, Decyltrimethoxysilane, Tetraethoxysilane, Methyltriethoxysilane, Dimethyljetoxysilane Toxysilane, phenyltriethoxysilane, diphenyljethoxysilane, bistrimethylacetamide trimethylsilylacetamide, bistrimethylsilylurea, t
ert-butyldimethylchlorosilane, isopropyl triisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, tetraisopropylbis(dioctyl phosphite) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, Tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, bis(dioctylpyrophosphate)ethylene titanate, isopropyltrioctanoyl titanate, isopropyl dimethacrylylisostearoyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, isopropyl tri(N-amidoethyl◆aminoethyl) titanate, dicumylphenyloxyacetate titanate, diisostearoyl ethylene titanate, acetalkoxyaluminum diisopropiate, etc. Can be mentioned.

Among these coupling agents, those having a boiling point of 150° C. or higher, such as γ-glycidoxypropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane, are particularly easy to handle.

Further, examples of organic peroxides added to the adhesive in the present invention include benzoyl peroxide, isononanoyl peroxide, lauroyl peroxide, t-butyl per-2-ethylhexanoate, 1.1- Bis(t-butylperoxy) 3.3.5, -1-limethylcyclohexane, t-butylperoxyisopropyl carbonate, t-butylperoxybenzoate, methyl ethyl ketone peroxide, t-butyl hydroperoxide,
Examples include dicumyl peroxide, cumene hydroperoxide, di-t-butyl peroxide, and the like. Among these organic peroxides, the half-life temperature is between 60℃ and 100℃.
Examples include benzoyl peroxide, isononanoyl peroxide, and t-butyl peroxide.
-ethylhexanoate, cumene hydroperoxide,
].

]1-bistershari-butylperoxy)3゜3.5
-trimethylcyclohexane, etc.

Furthermore, in the present invention, in addition to these additives, there is no problem in adding surfactants, stabilizers, antioxidants, etc. to improve wettability.

[Effects of the Invention] As described above, according to the invention, (1) optical disks with excellent weather resistance and long-term reliability can now be provided industrially.

(2) It has become possible to prevent deformation and distortion of the substrate during the heating and curing process of the adhesive, making it possible to manufacture highly reliable optical discs at a high yield.

■ Adhesive no longer protrudes from between the substrates during the adhesive heat curing process, eliminating the need to remove protruding adhesive, simplifying the manufacturing process, and eliminating the occurrence of defects associated with adhesive removal. was completed.

[Brief explanation of drawings]

FIG. 1 is a main sectional view showing an embodiment of the optical disc of the present invention. FIG. 2 is a main process diagram showing an embodiment of the optical disc manufacturing method of the present invention. FIG. 3 is a main sectional view showing a conventional optical disc. 1.9 Polycarbonate substrate 2.10 StAρN first protective layer 11 NdDyFeCo recording layer 12 5iA (IN second protective layer 13 A, 17 layers 14 5i AINo layer 15・Hard coat layer... Center hole... Area on the outer periphery of the substrate where the recording layer is not formed... Area on the inner periphery of the substrate where the recording layer is not formed ・Center hole of the disk ・Dispenser ring Adhesive layer coated in the shape Heater Metal halide lamp UV rays Oven Polycarbonate substrate 5iAJ7N layer 23 ・ ・ ・ 24 ・ ・ ・ 25 ・ ・ ・ 26 ・ ・ ・ 27 ・ ・ ・ 28 ・ ・ 29 ・ ・・ 30.36 31.37 22・ ・ 32. 33. 34. 35・ 41. 43 ・ 38・Three TbFeCo layers・5iApN layer 40・A1 layer...Adhesive layer 42・Hard coat layer...Center hole

Claims (9)

[Claims] (1) In an optical disc having a first substrate, a second substrate, and an adhesive layer for bonding the first substrate and the second substrate, a first protective layer extending over the substrate; a recording layer provided on the first protective layer; a second recording layer extending on the recording film;
a protective layer, the reflective layer extending over the second protective layer and provided in a region outside the center hole provided in the substrate and inside the outer diameter of the substrate; and the reflective layer. characterized by having a ceramic layer extending over the top and extending in a region surrounded by a diameter smaller than the inner diameter of the reflective layer and the recording layer and a diameter larger than the outer diameter of the reflective layer and the recording layer. optical disc. (2) An optical disc having a first substrate, a second substrate, and an adhesive layer for bonding the first substrate and the second substrate, wherein the adhesive layer is made of a thermosetting resin and an ultraviolet curable resin. An optical disc characterized by comprising: (3) the substrate includes a first protective layer extending over the substrate, a recording layer provided on the first protective layer, and a second protective layer extending over the recording film; 3. The optical disc according to claim 2, further comprising a reflective layer extending over the second protective layer and provided in a region outside the center hole and inside the outer diameter of the substrate. (4) The optical disc according to claim 1 or 3, wherein the recording layer is made of a rare earth-transition metal alloy. (5) The optical disc according to claim 1 or 3, wherein a recording layer is formed on one of the first substrate and the second substrate. (6) comprising a first substrate, a second substrate, and an adhesive layer for bonding the first substrate and the second substrate, forming a thin film on the substrate; and and the step of bonding the second substrate together, the step of applying an adhesive made of a thermosetting resin and an ultraviolet curable resin to the first substrate or the second substrate, The method includes the steps of bonding the first substrate and the second substrate, an ultraviolet irradiation step of irradiating the bonded substrates with ultraviolet rays, and a step of heating the bonded substrates after the ultraviolet irradiation step. A method for manufacturing an optical disc characterized by: (7) The step of forming a thin film on a substrate includes a step of forming a first protective layer extending on the substrate, a step of forming a recording layer on the first protective layer, and a step of forming a recording layer on the first protective layer. forming a second protective layer extending over the film; forming a second protective layer extending over the second protective layer outside a center hole provided in the substrate and inside an outer diameter of the substrate; forming a reflective layer in a region extending above the reflective layer and inside the inner diameter of the reflective layer and the recording layer and outside the outer diameter of the reflective layer and the recording layer; 7. The method of manufacturing an optical disc according to claim 6, further comprising the step of forming a ceramic layer. (8) The method for manufacturing an optical disc according to claim 7, wherein the recording layer is made of a rare earth-transition metal alloy. (9) The method of manufacturing an optical disc according to claim 7, wherein the recording layer is formed on one of the first substrate and the second substrate.