JPH0242657A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To allow adhering and joining of two sheets of transparent substrates and to improve preservable stability by incorporating a polymerizable monomer selected from a specific acrylic monomer or methacrylic monomer and a prepolymer, etc., contg. polybutadiene as its main chain and having an acrylic group or methacrylic group, etc., as an adhesive agent. CONSTITUTION:This recording medium is constituted of an information recording layer 2, a transparent substrate 1 and the adhesive agent 7. The adhesive agent 7 is prepd. by incorporating 100pts.wt. polymerizable monomer selected from the acrylic monomer or methacrylic monomer contg. >=50wt.% isoboronyl acrylate and/or isoboronyl methacrylate, 25-100pts.wt. prepolymer contg. the polybutadiene as its main chain and having the acrylic group or methacrylic group as its both ends or side chains, 0.1-20pts.wt. polymn. initiator, and 0.1-20 pts.wt. polymn. accelerator. Well adhering and joining of two sheets of the transparent substrates 1, 1 are possible in this way and the reliability and preservation stability are improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention is a video disc memory, a document file.

The present invention relates to optical information recording media used as computer memory, etc.

[Conventional technology]

In general, there are three types of optical information recording media (hereinafter also referred to as "optical discs"): read-only type, write-once type where the user can write once, and rewritable type where the user can freely erase and write. All of these have the same basic configuration; information is reproduced by rotating an optical disk on which information is recorded, focusing a laser beam onto the optical disk, and detecting the strength of the reflected light from the optical disk. .

FIG. 2 shows three typical structures of such optical discs: a single-sided recording type, a double-sided recording type, an air sandwich structure, and a close-contact structure.

As shown in the same figure (A), a single-sided recording type optical disc has an information recording layer S layer 2 provided on one surface of a transparent substrate 1 made of plastic or glass that has concavities and convexities. The top is covered with a protective layer 3 for protection. Among the double-sided recording types, the adhesive structure has two transparent substrates 1 each having an information recording layer 2 on one side, with the information recording layer 2 on the inside, as shown in Figure (C). They are joined together with spacers 4 in the center and periphery interposed therebetween, facing each other. Among the double-sided recording types, those with an air sandwich structure have an information recording layer 2 on one side, as shown in Figure (B).
Two transparent substrates 1 with ! 7° information recording layer 2
They are placed in close contact with each other through an adhesive layer 5, facing each other with the two sides facing each other.

In this way, in an optical disc, the information recording layer is contained within the disc and is not exposed to the outside. When a laser beam for information reproduction is focused on such an optical disk from the outside, the laser beam passes through the transparent substrate 1 and reaches the information recording layer 2, and the reflected light from the information recording layer 2 passes through the transparent substrate 1 again. and exit the disc. At this time, even if there is dust or the like on the disk surface, that is, on the outer surface of the transparent substrate 1, it has little effect because it is outside the focus of the laser beam. Furthermore, when the laser beam for information recording or erasing is focused, the laser beam passes through the transparent substrate 1 and reaches the information recording layer 2 .

Here, the principles of recording and reproducing an optical disc will be explained with reference to FIG.

In read-only optical discs, information is recorded on the uneven surface of the disc. One unit of this record is called a pit (hole), and the presence or absence of a pit is ``1'' or ``o'' if it is a digital record.
Corresponding to this, in the case of analog recording, the length and spacing of pits are the information. Irregularities (pits) representing such information are formed in advance on the surface of the transparent substrate 1. The information recording layer 2 in this case is a reflective film formed on the uneven surface of the transparent substrate 1.

A write-once optical disc does not have the above-mentioned pit row of information before writing, but unevenness as track guide grooves and track address pits is formed in advance on one surface of the transparent substrate 1, and predetermined recording is performed on this uneven surface. A thin film or information recording layer 2 made of a material is formed. Information is recorded on this optical disk by making holes in the information recording layer 2 using a high-output laser beam or by changing the reflectance, and this operation can be performed only once for the same portion.

The rewritable optical disc has the same structure as the write-once optical disc described above, except for the recording material of the information recording layer. There are two types of optical disks: a magneto-optical type that uses a thermomagnetic effect, and a layer-denatured type that uses the difference in reflectance caused by the phase change between fine and amorphous materials.
Information can be erased and written by reversibly controlling the optical properties of the material.

In such optical discs, the information recorded on the disc must be stored stably for a long period of time without being affected by various environmental changes or mechanical stress, and in order to achieve this reliability, handling of the disc and Assuming the worst possible storage environment, it is necessary to provide performance that can withstand such conditions.

Therefore, various improvements have been made to the information recording layer and the transparent substrate. For example, Te is used as the main component in the information recording layer (recording film) of write-once optical discs, but since this metal is extremely susceptible to oxidation and deterioration, it is necessary to prevent corrosion without impairing recording and playback characteristics. Various improvements have been made to the transparent substrate, and acrylic resin with good optical properties, which is used in eyeglass lenses, is used for the transparent substrate, but this acrylic resin has a large warp due to moisture absorption, so it is necessary to suppress moisture absorption. Various improvements have been made.

Regarding adhesives, if the optical disc has a single-sided recording type structure as shown in FIG. Since they were not in contact, it was sufficient to simply obtain adhesive strength that would prevent them from peeling off, so no particular improvement in the adhesive was necessary. However, in each of these structures, it is not possible to increase the thickness of the transparent substrate due to optical performance, and the thickness must be made as thin as 1.2 mm N degrees, which results in insufficient strength of the disk, resulting in distortion, Distortion and warping are likely to occur, making it difficult to achieve high reliability. On the other hand, when the optical disc has a close-contact structure as shown in Figure (C), the disc is thicker and the two transparent substrates mutually reinforce each other, which has the advantage that bending, distortion, warping, etc. are less likely to occur. .

By the way, in the conventional adhesive structure type optical disk, a hot melt adhesive or an ultraviolet curing adhesive is used as an adhesive for bonding two transparent substrates together.

(1lffl which the invention seeks to solve) However,
The former is hot melt adhesive.

Not only does it take a long time to harden and has poor workability, but since the main component is thermoplastic resin, it softens as the temperature rises even after bonding, resulting in a decrease in bond strength.As a result, when the disk is stored at high temperatures, etc. The adhesive layer between the two transparent substrates is likely to deform, causing misalignment, bending, distortion, warping, etc. of the transparent substrates, and peeling of the transparent substrates may also occur, which impairs information recording and reproducing functions. There is a problem with how to do it.

Furthermore, although the latter ultraviolet curable adhesive is excellent in terms of adhesive performance and adhesive time, it has the problem of corroding the information recording layer. This corrosion of the information recording layer is caused by, for example: (1) Ultraviolet curable adhesives before curing are highly reactive and take a long time to cure, so they are corroded by the monomer;
It is corroded by the residual ions after curing, ■ If the adhesive strength is strong, it will corrode because it adheres to the adherend, and ■ If the adhesive strength is weak, local peeling will occur due to changes in temperature and humidity, and the area will become corroded. There is a form in which water droplets accumulate and corrode.

Particularly in the case of optical discs with adhesive structure, the storage characteristics may depend more on the properties of the adhesive than on the performance of the information recording layer or transparent substrate, and since the information recording layer does not transmit ultraviolet rays, UV-curable adhesives Even when an adhesive is used, it is necessary to provide curability such as anaerobic curability in addition to UV curability, which limits the performance of the adhesive and increases the dependence on the performance of the adhesive.

The present invention has been made in view of point E.

An object of the present invention is to efficiently mass-produce an optical information recording medium that can bond two transparent substrates together well and has excellent reliability and storage stability.

[Means to solve the problem]

In order to achieve the above object, the present invention as set forth in claim 1 (hereinafter referred to as the "first invention") includes: (1) containing 50% or more of isobornyl acrylate and/or isobornyl methacrylate as an adhesive; 100 parts by weight of a polymerizable monomer selected from acrylic monomers or methacrylic monomers, and (2) a prepolymer 25 having polybutadiene as the main chain and acrylic or methacrylic groups on both ends or side chains.
An adhesive composition containing ~100 parts by weight, (1) 0.1 to 20 parts by weight of a polymerization initiator, and (2) 0.1 to 20 parts by weight of a polymerization accelerator was used.

In addition, the present invention according to claim 2 (hereinafter referred to as the "second invention") includes: (1) isobornyl acrylate monomer and/or isobornyl methacrylate monomer 1 as an adhesive;
(2) 25 to 100 parts by weight of a prepolymer having polybutadiene as the main chain and acrylic or methacrylic groups at both ends or side chains; (2) 0.1 to 20 parts by weight of a polymerization initiator;
(1) 0.1 to 20 parts by weight of a polymerization accelerator.

■ 50% isobornyl acrylate and/or isobornyl methacrylate of the adhesive composition used in the first invention
The polymerizable acrylic monomer or methacrylic monomer containing 1% or more by weight, for example, inbornyl (meth)
In addition to acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, butoxyethyl (meth)acrylate, ethyldiethylene glycol (meth)acrylate, 2-ethylhexyl (meth)acrylate Acrylate, cyclohexyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-
Hydroxy-3-phenyloxypropyl (meth)acrylate, dicyclopentadiene (meth)acrylate, trimethylolpropane tri(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, 1,6-hexanethiol di(meth)acrylate ) acrylate,
Examples include neopentyl glycol di(meth)acrylate, tri(meth)acryloxyethyl phosphate, and the like.

This acrylic monomer or methacrylic monomer may be entirely composed of isobornyl acrylate and/or isobornyl methacrylate, as in the adhesive composition used in the second invention.

In addition, below, a polymerizable acrylic monomer or methacrylic monomer (the first
(■) of the invention and inbornyl acrylate and/or isobornyl methacrylate (■) of the second invention,
Also collectively referred to as "component".

Moisture resistance and adhesive strength of the cured product of the adhesive composition obtained when the blending ratio of inbornyl acrylate or isobornyl methacrylate contained in this acrylic monomer or methacrylic monomer is less than 50% by weight. may decrease.

In addition, (2) of the adhesive composition used in the present invention, a prepolymer (hereinafter referred to as "prepolymer") having polybutadiene as the main chain and having acrylic or methacrylic groups at both ends or side chains.

Polybutadiene having terminal hydrogen groups (also referred to as "Component
3000 (both manufactured by Nippon Soda Co., Ltd., product name), P
OLY BD R-45HT (manufactured by Idemitsu Petrochemical,
(trade name) etc., by reacting a terminal hydroxyl group-containing acrylic monomer or methacrylic monomer with a diisocyanate, or by esterifying a carboxyl group-containing acrylic monomer or methacrylic monomer to form an acrylic or methacrylic group at the terminal. This can be obtained by methods such as introducing .

The blending ratio of this prepolymer is 25 to 100 parts by weight per 100 parts of component (1). If the blending ratio of this prepolymer is less than the 25-layer base portion, it may attack the adhered surface of the transparent substrate made of transparent resin.
If the amount is more than 100 parts by weight, the curing speed of the adhesive composition may be reduced or the adhesive strength of the cured product may be reduced.

Furthermore, ■polymerization initiator () of the adhesive composition used in the present invention
Hereinafter, it is also referred to as "■component". ) include diacyl oxide, ketone peroxide, hydroperoxide, dialkyl peroxide, peroxy ester, etc. More specifically, for example, pensoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, etc. Examples include peroxide, methyl ethyl ketone peroxide, t-butyloxyacetate, and other known free radical generators.

These organic peroxides can be used singly or as a mixture of two or more.

The blending ratio of this polymerization initiator is 0.1 to 20 parts by weight based on the amount of component (2) tooit. In this case, if the blending ratio of one polymerization initiator is less than 0.1 part by weight, the polymerization reaction rate may be too slow, and if the blending ratio is more than 20 parts by weight, the stability of the adhesive composition may deteriorate.

Furthermore, as (1) polymerization accelerator (hereinafter also referred to as "■ component") of the adhesive composition used in the present invention, for example,
Examples include tertiary amines, thioureas, organic salts of metals, reducing organic compounds, etc. More specifically, for example, dimethylaniline, N,N dimethylpara-toluidine, N,N diethylaniline, thiourea, ethylene thio Urea, benzoylthiourea, acetylenethiourea, benzoylthiourea, acetylthiourea, tetramethylthiourea, 1゜3-
Examples include butylthiourea, cobalt naphthenate, nickel naphthenate, copper naphthenate, lauryl mercaptan, p-toluenesulfonic acid, and ascorbic acid. The polymerization accelerator used in the present invention can be used singly or as a mixture of two or more.

The blending ratio of this polymerization accelerator is 1 to 20 parts by weight of O per 100 parts by weight of component (1).In this case, if it is less than 0.1 part by weight, the polymerization reaction rate may be too slow;
If the amount is more than 0 parts by weight, the adhesive strength and moisture resistance of the cured product may decrease.

In addition to the above-mentioned components, the adhesive composition used in the present invention may contain a polymerization inhibitor and a coloring agent.

Here, examples of the polymerization inhibitor include hydroquinone, benzoquinone, t-butylcatechol, and hydroquinone monomethyl ether.

Further, the adhesive composition used in the present invention may contain, for example, a photopolymerization initiator in addition to the above-mentioned components. By containing this photopolymerization initiator in the composition, the adhesive composition can be easily polymerized and cured by irradiation with light such as ultraviolet rays.

Examples of the photopolymerization initiator include benzoin compounds such as benzoin, benzoin methyl ether, and benzoin ethyl ether; carbonyl compounds such as benzyl, benzophenone, acetophenone, 2,2-jethoxyacetophenone, and Michler's ketone; azobisisobutylnitrile; Examples include azo compounds such as azobenzoyl; sulfur compounds such as dibenzothiazyl disulfide and tetraethylthiuram disulfide; halides such as carbon tetrabromide and tribromphenyl sulfone; and benzanthraquinone.

The blending ratio of this photopolymerization initiator is 0.1 parts by weight to 10 parts by weight per 100 parts by weight of component (1).

Furthermore, depending on the combination of the above-mentioned polymerization initiator and polymerization accelerator, it is possible to impart anaerobic curing properties to the adhesive composition of the present invention.

In order to bond two transparent substrates of an optical disk using the adhesive composition mentioned above, for example, a two-component adhesive in which a polymerization initiator and a polymerization accelerator are separated in the adhesive composition is used. After blending the composition and applying a component system containing a polymerization initiator to the adhesion surface of one transparent substrate, and applying a component system containing a polymerization accelerator to the adhesion surface of the other transparent substrate, Align and adhere the surfaces of both transparent substrates.

It is also possible to mix the components of the adhesive composition described above immediately before bonding two transparent substrates together, or to mix the two-component yarn as described above and apply the mixture to the adherend surface.

Therefore, in order to manufacture an optical disc by bonding the information recording layers of two transparent substrates of an optical disc, for example, the component system (a) and component system (b) of the following two-component composition must be adjusted respectively. After applying the component system (A) to one information recording layer and the component system (B) to the other information recording layer, the component system (A),
The surfaces coated with the component system (b) are aligned to bond both information recording layers.

Component system (a): A (meth)acrylate monomer containing inbornyl (meth)acrylate in an amount of 50% or more of heavy paper.

A mixture consisting of a polybutadiene prepolymer containing (meth)acrylate groups and a polymerization initiator.

A (meth)acrylate monomer containing 50% by weight or more of inbornyl (meth)acrylate, a polybutadiene prepolymer containing a (meth)acrylate group,
A mixture consisting of a polymerization accelerator.

Further, the adhesive composition used in the present invention has the following component system (
The composition can also be composed of c) and (d) or component systems (e) and (f), by applying component system (c) or component system (e) to one adhering surface, and then applying component system (d) or component system (e). Ingredient system (to)
may be applied to the other adhering surface.

Composition component system (c) consisting of component system (c) and (d); (meth)acrylate simple body containing 50% by weight or more of isobornyl (meth)acrylate; and a polybutadiene-based prepolymer containing (meth)acrylate groups. A mixture consisting of a polymerization initiator.

Component system (d): A set consisting of a polymerization accelerator solution component system (e) and (f) in which a polymerization accelerator alone is dissolved in a solvent.

Component system (e): A mixture consisting of a (meth)acrylate monosoft material containing 50% by weight or more of isobornyl (meth)acrylate, a polybutadiene prepolymer containing a (meth)acrylate group, and a polymerization accelerator.

Component system (f): Polymerization accelerator solution in which a polymerization initiator alone is dissolved in a solvent.

In addition, compositions consisting of the above component systems (a) and (b), compositions consisting of the component systems (c) and (d), component systems (e) and (
By adding a photopolymerization initiator to each component system of the composition consisting of (v), the adhesive composition used in the present invention can be cured by ultraviolet irradiation.

(Before applying the adhesive composition used in the present invention to the information recording layer as the adherend surface, a primer prepared by dissolving the above-mentioned polymerization accelerator contained in the adhesive composition in a solvent is applied in advance.) It may also be applied to the information recording layer.

〔Example〕

An embodiment of the present invention will be described below with reference to the accompanying drawings.

First, the process of adhering an optical disc according to the present invention will be explained with reference to FIG.

First, two transparent substrates 1 made of plastic or glass are prepared. On one side of the transparent substrate 1, track guide grooves and irregularities as track address bits are formed. For example, chalcogenide T
An information recording layer 2 is formed by forming a film of a recording material containing o as a main component by a vacuum evaporation method or a sputtering method.

When bonding the two transparent substrates 1.1, first, a primer 6 dispersed in a solvent is uniformly applied onto each information recording layer 2 of the two transparent substrates 1, 1 using a spinner or the like.

Next, an adhesive 7 (specific examples thereof will be described later) having both ultraviolet curability and primer contact curability is applied to the entire surface of each transparent substrate 1 on the information recording layer 2 side. After that, the two transparent substrates 1 are pasted together, and the lamp 8
One surface of the transparent substrate is irradiated with ultraviolet light S from.

As a result, the ultraviolet rays 7 pass through the transparent substrate 1 and reach the adhesive 7 in the areas where the information recording layer 2 is not present, and the adhesive 7 in the areas exposed to the ultraviolet rays 7 hardens in about a few seconds. 1.1 adheres with sufficient strength for temporary fixing.

In a certain part of the information recording layer 2, the adhesive 7 is a primer 6.
It will completely harden if left at room temperature for about 24 hours. Even until it is completely cured, both transparent substrates 1.1 are temporarily fixed by the adhesive 7 cured by ultraviolet irradiation, so there is no inconvenience in handling until it is completely cured, and workability is very good.

In this way, by bonding two transparent substrates with an adhesive that has both UV curability and primer contact curability, workability is improved by temporary curing during the manufacturing process, and once fully cured, it can be heated to high temperatures. Provides strong and excellent adhesion.

Thereby, optical information recording media with excellent reliability and long-term storage can be efficiently mass-produced.

Note that even if the primer is applied only to the information recording layer of one transparent substrate, there is no significant difference in the effect. Further, in this example, an example was described in which an adhesive having both ultraviolet curability and primer contact curability was used as the adhesive composition, but the adhesive composition is not limited to this.

Next, specific examples of the adhesive composition used in the present invention will be described.

(Hereinafter in the margin) "Ten" Liu U221 Component system A and component system B constituting the adhesive compositions according to Examples 1 to 8 were blended at the blending ratios shown below.

Example 1; (Component system A) Isoboronyl methacrylate...80 doublet part Polybutadiene dimethacrylate...20 doublet part Hydroquinone monomethyl ether...0.1 part by weight Cumene hydroperoxide...1 .5 parts by weight Photopolymerization initiator (Irgacure 184, trade name manufactured by Ciba Geigy)...2 parts by weight (component system B) Isobornyl methacrylate...80 parts by weight Polybutadiene dimethacrylate...20 parts by weight Hydroquinone monomethyl ether...0.1 parts by weight Ethylene thiourea...Type 1 broken copper naphthenate...4 parts by weight Photopolymerization initiator (Irgacure 184, trade name manufactured by Ciba Geigy)
...2 parts by weight Example 2; (Component system A) Isobornyl methacrylate ...30 parts by weight dicyclopentenyl acrylate...10 parts by weight 2-hydroxyethyl methacrylate...10 parts by weight polybutadiene Dimethacrylate...50 parts by weight Hydroquinone monomethyl ether...0.1 parts by weight Methyl ethyl ketone hydroperoxide...1.
5 parts by weight Benzoin ethyl ether... 2 parts by weight (component system B) Isobornyl methacrylate... 30 parts by weight Dicyclopentenyl acrylate... 10 parts by weight 2-hydroxyethyl methacrylate... 10 parts by weight Poly Butadiene dimethacrylate...50 parts by weight Hydroquinone monomethyl ether...0.1 parts by weight Copper naphthenate...4 parts by weight Dicyandiamide...1 part by weight Benzoin ethyl ether...2 parts by weight Example 3; Component system A) Isobornyl methacrylate...40 parts by weight 2-hydroxyethyl methacrylate...10 parts by weight Phenoxyethyl acrylate...10 parts by weight Polybutadiene dimethacrylate...40 parts by weight Hydroquinone monomethyl ether...・0.1 mold break Cumene hydroperoxaod...1.5 parts by weight (component system B) Isobornyl methacrylate...40 ffl Kibe 2-hydroxyethyl methacrylate...10 parts by weight phenoxyethyl acrylate ...10 parts polybutadiene dimethacrylate...40 parts by weight Hydroquinone monomethyl ether...0.1 part by weight Ethylene thiourea...1 part by weight Copper naphthenate...4 parts by weight Example 4; (Component system A) Isobornyl methacrylate...so heavy part Dicyclopentenyl acrylate...10 parts by weight 2-hydroxyethyl methacrylate...15 parts by weight Polybutadiene dimethacrylate...25 parts by weight Hydroquinone monomethyl Ether...0.1 part by weight Methyl ethyl ketone hydroperoxaide...1.
5 parts by weight Benzoin ethyl ether 2 parts by weight (component system B) Isobornyl methacrylate 50 parts by weight Dicyclopentenyl acrylate 10 parts by weight 2-hydroxyethyl methacrylate 2-hydroxyethyl methacrylate IS main part Polybutadienzi Methacrylate...25 double line area Hydroquinone monomethyl ether...0.1 part by weight Copper naphthenate...5 parts by weight Benzoin ethyl ether...2 area area Example 5; (Component system A) Isobornyl Methacrylate...35 parts by weight 2-hydroxyethyl methacrylate...15 parts by weight Phenoxyethyl acrylate...15 parts by weight Polybutadiene dimethacrylate...35 parts by weight Hydroquinone monomethyl ether...0.1 part by weight Cumene Hydroperoxaodo...1.5 parts by weight Photopolymerization initiator (Pycure 55. trade name manufactured by Stouffer Chemical Company)...2 parts by weight (component system B) Isobornyl methacrylate...35 parts by weight Dicyclo Pentenyl acrylate...15 parts by weight 2-Hydroxyethyl methacrylate...15 parts by weight Polybutadiene dimethacrylate...35 parts Hydroquinone monomethyl ether...0.1 Mold broken part Ethylene 1,000 parts by weight...1 weight Part copper naphthenate...4 parts by weight Photopolymerization initiator (Bicure 55. trade name manufactured by Stouffer Chemical Co.)
...2 parts by weight Example 6; (Component system A) Isobornyl methacrylate...35 parts dicyclopentenyl acrylate...15 parts 2-hydroxyethyl methacrylate...15 parts poly Butadiene dimethacrylate...35 parts by weight Hydroquinone monomethyl ether...0.1 parts by weight Methyl ethyl ketone hydroperoxide...1.
5 parts by weight (component system B) Isobornyl methacrylate...35 parts by weight 2-hydroxyethyl methacrylate...15 parts by weight Phenoxyethyl acrylate...15 parts by weight Polybutadiene dimethacrylate...35 parts by weight Part hydroquinone monomethyl ether...0.1 part by weight Copper naphthenate...4 parts by weight Dicyandiamide...1 part by weight Example 7; (Component system A) Isobornyl methacrylate...35 parts by weight 2- Hydroxyethyl methacrylate...15 parts by weight Phenoxyethyl acrylate...15 parts by weight Polybutadiene dimethacrylate...35 parts by weight Hydroquinone monomethyl ether...0.1 part by weight Cumene hydroveroxaode...1. 5 parts by weight (component system B) Ethylene thiourea ... 1 part by weight Copper naphthenate ... 4 parts by weight Isobutanol ... 95 parts by weight Example 8; (component system A) Isobornyl methacrylate ... 30 Heavy part Dicyclopentenyl acrylate...10 parts by weight 2-hydroxyethyl methacrylate...15 parts by weight Polybutadiene dimethacrylate...45 parts by weight Hydroquinone monomethyl ether...0.1 part by weight Methyl ethyl ketone hydroperoxide...・1.
5 parts by weight Photopolymerization initiator (Irgacure 184, Ciba Geigy brand name) 2 parts by weight (component system B) Copper naphthenate 5 parts by weight Isobutanol 95 parts by weight and Examples 1- Regarding the compositions according to No. 8, after applying component system A to one information recording layer of an optical disc and component system B to the other information recording layer, the surfaces coated with component system A and component system B were combined and both were coated. The information recording layers were bonded together to produce optical discs according to Examples 1 to 8.

Comparative Examples 1 and 2 Component system a and component system A for forming the adhesive compositions of Comparative Examples 1 and 2 were blended at the blending ratios shown below.

Comparative Example 1; (Component system a) Isobornyl methacrylate...35 heavy seams 2-hydroxyethyl methacrylate...15 parts by weight Phenoxyethyl acrylate...15 parts by weight Polyester urethane acrylate...35 parts by weight hydroquinone Monomethyl ether...0.1 parts by weight Cumene hydroperoxaod...1.5 parts by weight Benzoin ethyl ether...2 parts by weight (component system b) Isobornyl methacrylate...35 parts by weight 2- Hydroxyethyl methacrylate...15 parts by weight Phenoxyethyl acrylate...15 parts by weight Polyester urethane acrylate...35 parts by weight Hydroquinone monomethyl ether...0.1 part by weight Ethylene thiourea...1 part by weight Naphthenic acid Copper: 4 parts Benzoin ethyl ether: 2 parts by weight Comparative Example 2 (Component system a) Dicyclopentenyl acrylate: 35 parts by weight 2-hydroxyethyl methacrylate: 10 parts by weight Phenoxyethyl acrylate 10 parts by weight Polybutadiene dimethacrylate 45 parts by weight Hydroquinone monomethyl ether 0.1 part by weight Methyl ethyl ketone hydroperoxide 1.
5 parts by weight Photopolymerization initiator (Irgacure 184. Trade name manufactured by Ciba Geigy)...Double electric part (component system b) Dicyglopentenyl acrylate...35 parts by weight 2-hydroxyethyl methacrylate...10 parts by weight Phenoxyethyl acrylate...10 parts Polybutadiene dimethacrylate...45 parts by weight Hydroquinone 1,000 parts Methyl ether...0.1 part Copper naphthenate...4 parts Dicyandiamide...1 broken part Mitsushigeima initiator (Irgacure 184. Ciba Geigy product name)
...2 parts by weight For each of the compositions of Comparative Examples 1 and 2, component system a was added to one information recording layer of the optical disc and component system a was added to the other information recording layer in the same manner as in the example. After coating, the surfaces coated with component system a and acid component system A were brought together and both information recording layers were bonded together to produce optical discs according to comparative examples 1 and 2.

(Evaluation Test) The adhesive compositions of Examples 1 to 8 and Comparative Examples 1 to 2 described above were subjected to the following evaluation test.

(1) “Rinj” u1 is lost.

The information recording layers of two polycarbonate substrates each having an information recording layer formed on one side were placed facing each other, and Example 1 was applied to each joint surface.
- 8 and Comparative Examples 1 and 2 were applied and bonded together, and the time (h) required for complete curing was determined.

(2) Measuring the curing speed of ultraviolet rays Similar to the curing speed measurement test in (1) above, the information recording layer of two polycarbonate substrates with an information recording layer formed on one side were placed facing each other, and each Examples 1, 2, 4,
The adhesive compositions according to No. 5.8 and Comparative Example 2 were applied and bonded together, irradiated with ultraviolet rays at an irradiation intensity of 150 mw/ci, and the time (see) until complete curing was measured.

(3) Measurement of tensile breaking adhesive strength according to JIS K6850 Examples 1 to 8 and Comparative Examples 1 to
For the adhesive composition according to 2, j) tensile shear adhesive strength (kg/alt) immediately after completely curing, 1i) 60"C195 after UV curing as an IT condition test.
Tensile shear adhesive strength (k) after 100 hours under %RH
g/cd) was measured.

In addition, after ultraviolet curing, it is 5000 mj/aJ.

(4) Confirmation of the influence on the information recording layer i) After measuring the curing speed during ultraviolet irradiation in L. (2), the presence or absence of any influence on the information recording layer was confirmed after 24 hours had elapsed.

ii) After the moisture resistance test in (3) ii) above, further test at 60C
After 1000 hours under 195% RH, it was confirmed whether there was any influence on the information layer.

The results of the evaluation tests in (1) to (4) above were used in Examples 1 to 4.
4 is shown in Table 1, Examples 5 to 8 are shown in Table 2, and Comparative Examples 1 to 2 are shown in Table 3.

Table 1 Table 2 Table 3 (Effects of the Invention) As explained below, according to the present invention, isobornyl acrylate and/or isobornyl methacrylate is
A polymerizable monomer selected from acrylic monomers or methacrylic monomers containing 0% by weight or more, or inbornyl acrylate monomer and/or isobornyl methacrylate monomer 100 type broken part, and polybutadiene as the main chain.

25 to 100 parts by weight of a prepolymer having acrylic or methacrylic groups at both ends or side chains, and 0.1 to 100 parts by weight of a polymerization initiator.
Since we used an adhesive containing 20 parts by weight and 0.1 to 20 parts by weight of a double polymerization accelerator, this adhesive has a fast curing speed and is suitable for mass production, and has low corrosion resistance to plastics and is reliable. In addition, the moisture resistance is improved, and thereby two transparent substrates can be bonded together well, and optical information recording media with excellent M reliability and storage stability can be efficiently mass-produced.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view for explaining the structure and adhesion process of an optical information recording medium according to the present invention, and FIG. 2 is a cross-sectional view showing three types of structural examples of the optical information recording medium. In the drawings, 1 is a transparent substrate, 2 is an information recording layer, 6 is a primer, and 7 is an adhesive. Figure C=2=2=D-8

Claims (1)

[Scope of Claims] 1. An optical information recording medium comprising a layer-change type or magneto-optical information recording layer, a transparent substrate made of transparent resin or transparent glass, and an adhesive, wherein the adhesive is the following (1).
An optical information recording medium characterized by being a composition containing (4). (1) Polymerizable monomer selected from acrylic monomers or methacrylic monomers containing 50% by weight or more of isobornyl acrylate and/or isobornyl methacrylate...100 parts by weight (2) Polybutadiene Prepolymer with acrylic or methacrylic groups on both ends or side chains as the main chain...2
5 to 100 parts by weight (3) Polymerization initiator...0.1 to 20 parts by weight (4) Polymerization accelerator...0.1 to 20 parts by weight2 Layer change type or magneto-optical information recording layer, In an optical information recording medium composed of a transparent substrate made of transparent resin or transparent glass and an adhesive, the adhesive meets the following (1)
An optical information recording medium characterized by being a composition containing (4). (1) Isobornyl acrylate monomer and/or isobornyl methacrylate monomer...100 parts by weight (2) Prepolymer with polybutadiene as the main chain and acrylic or methacrylic groups on both ends or side chains.・・２
5 to 100 parts by weight (3) Polymerization initiator...0.1 to 20 parts by weight (4) Polymerization accelerator...0.1 to 20 parts by weight