JPS6341189A - Information recording medium - Google Patents

Abstract

PURPOSE:To write and/or read information using laser beam of high energy density, by containing a modified polymer of an unsaturated compound containing a 4 or more C unsaturated hydrocarbon compound as a main component in a recording layer and/or an intermediate layer. CONSTITUTION:A modified polymer of an unsaturated hydrocarbon compound containing a 4 or more C unsaturated hydrocarbon compound as a main component is contained in the intermediate layer between a substrate and a recording layer, the recording layer or both of the intermediate layer and the recording layer to realize the marked enhancement of sensitivity in an information recording medium. As an embodiment of the modified polymer, there is a copolymer of the 4 or more C unsaturated hydrocarbon compound and an oxygen-containing monomer selected from acrylic acid, methacrylic acid, maleic acid, maleic anhydride, phthalic acid, itaconic acid, a derivative thereof, vinyl acetate and a vinyl monomer having an epoxy group or a hydroxyl group. As the modified polymer to be used, a low MW one having average MW of about 100-10,000 is desirable.

Description

[Detailed description of the invention] [Field of invention] The present invention relates to a heat moat recording medium.

More specifically, the present invention relates to an information recording medium on which information can be written and/or read using a high energy density laser beam.

[Technical Background of the Invention and Prior Art] In recent years, laser beams have been focused into a high power density spot to irradiate a recording medium to selectively melt, evaporate, remove, and/or deform portions of the recording medium. The heat-mode laser recording method, which records information using a laser beam, is attracting attention as a new recording method with many excellent features.

The recording method described above is a real-time recording method that does not require post-processing such as heat development and fixing, or processing liquid, can form extremely high-resolution and high-contrast images, and the recording medium is indoor light. 7! It is not exposed to light, does not require darkroom operation, and is transmitted with time-series signals.
Since it is suitable for recording the momme signal and has the advantage of being able to add information later, that is, it can be used as an add-on, for example, optical discs such as video discs, audio discs, and even large-capacity discs. Still image files, large-capacity computer disk memory, micro image recording media, super micro image records! It is used or is being considered for use as a medium, COM, micro facsimile, original plate for phototypesetting, etc.

The recording medium used in the above recording method has a basic structure consisting of a transparent substrate made of plastic, glass, etc., and a recording material made of Bi, Sn, In, Te, other metals or semimetals, or pigments provided on this substrate. It has a layer. In addition, normal recording media have an intermediate layer (or undercoat layer) between the substrate and the recording layer that has features such as improving adhesion between these layers, improving recording sensitivity, and preventing contamination of the recording layer. It is equipped with

For example, in order to improve recording sensitivity,
As described in Japanese Patent Application Laid-open No. 126237 and Japanese Patent Application Laid-open No. 57-205193, between the substrate and the recording layer,
By providing a heat insulating layer made of organic polymer materials such as polyester, polyethylene, polystyrene, acrylic polymers, etc. or non-metals such as silicon dioxide, thermal energy caused by laser beam irradiation is lost through heat conduction from the recording layer to the substrate, etc. What techniques are known to reduce this? Also, in Japanese Patent Application Laid-open No. 55-46988,
Similarly, an invention is disclosed in which an intermediate layer containing brominated polyhydroxystyrene is provided between the substrate and the recording layer for the purpose of improving recording sensitivity.

Recently, a disk structure for protecting the recording layer has been constructed from two disc-shaped substrates, a recording layer is provided on at least one of the substrates, and these two substrates are attached to the inside of the recording layer. An air sandwich structure has been proposed in which a ring-shaped inner spacer and a ring-shaped outer spacer are joined to form a closed space.

In optical discs with such a structure, the recording layer does not come into direct contact with the outside air, and information is recorded and reproduced using laser light that passes through the substrate, so the recording layer may be damaged physically or chemically. It has the advantage that there is no possibility of dust or dust adhering to its surface, which will impede the recording and reproduction of information.

Information is written on a recording medium by irradiating the recording medium with a laser beam, for example, and the irradiated portion of the recording layer absorbs the light, causing a local temperature rise, resulting in physical or chemical damage. Information is recorded by making changes that change its optical properties. Reading information from a recording medium is also performed by irradiating the recording medium with a laser beam, and the information is reproduced by detecting reflected or transmitted light according to changes in the optical characteristics of the recording layer. .

Information recording media are extremely useful in various fields as described above, but it is desired that their recording sensitivity be as high as possible.

[Summary of the Invention] The main object of the present invention is to provide an information recording medium with improved recording sensitivity.

The present invention provides an information recording medium having a recording layer on a substrate, in which information can be written and/or read by a laser via an intermediate layer, wherein the recording layer and/or the intermediate layer is an unsaturated material having 4 or more carbon atoms. The information recording medium is characterized by containing a modified polymer of an unsaturated compound containing a hydrocarbon compound as a main component.

That is, the present invention provides an unsaturated compound (preferably By incorporating a modified polymer of (unsaturated hydrocarbon compound), a remarkable improvement in the sensitivity of an information recording medium is realized.

Conventionally, a layer made of a material having a heat insulating effect has been provided between the substrate and the recording layer to increase the sensitivity of the obtained information recording medium. It is possible to obtain a recording medium with even higher sensitivity than that of a recording medium having . Why is it possible to noticeably improve sensitivity by incorporating a modified polymer of an unsaturated compound containing as a main component an unsaturated hydrocarbon compound having 4 or more carbon atoms into the intermediate layer and/or recording layer of an information recording medium? The details of whether this will be realized are unknown, but due to its own excellent thermal properties when irradiated with a laser beam, this polymer can be It is presumed that this promotes thermal changes in the recording material.

[Structure of the Invention] The information recording medium of the present invention can be manufactured, for example, by the following method.

The substrate used in the present invention can be arbitrarily selected from various materials used as substrates for conventional information recording media. Optical properties, flatness, processability of the substrate,
In terms of ease of handling, stability over time, and manufacturing cost,
Examples of substrate materials include glass such as tempered glass; acrylic resins such as cell cast polymethyl methacrylate and injection molded polymethyl methacrylate; vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers; polyesters such as polyethylene terephthalate; and polycarbonate.

The surface of the substrate on which the recording layer is provided has improved flatness,
For the purpose of improving adhesive strength and preventing deterioration of the recording layer,
An undercoat layer may be provided.

Examples of materials for the undercoat layer include polymethyl methacrylate, acrylic acid/methacrylic acid copolymer, styrene/maleic anhydride copolymer, polyvinyl alcohol, N
- Methylolacrylamide, styrene/sulfonic acid copolymer, chlorinated polyethylene, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, polyester, polyimide, vinyl acetate/vinyl chloride copolymer,
Examples include polymeric substances such as ethylene/vinyl acetate copolymer, polyethylene, polypropylene, and polycarbonate.

Is the undercoat layer made of the above polymer? It can be formed by dissolving or dispersing V-quality in a suitable solvent and then applying this coating solution onto a substrate using a coating method such as spin code, dip coating, extrusion coating, bar code, screen printing, etc. can. The layer thickness of the undercoat layer is generally 0.
．． 01 to 20 JLm, preferably O,l to 1
It is 0gm.

Next, an intermediate layer is provided on the substrate either directly or via an undercoat layer. That is, the intermediate layer may also serve as an undercoat layer.

A modified polymer of an unsaturated compound containing as a main component an unsaturated hydrocarbon compound having 4 or more carbon atoms, which is a characteristic feature of the present invention, is contained in this intermediate layer or recording layer. Also,
It may be contained in both the intermediate layer and the recording layer. Note that the recording layer is often formed of a recording layer material such as a metal or semimetal on a substrate by methods such as vapor deposition, sputtering, or ion blasting, unless a coated material such as a dye is used as the forming material. Therefore, it is usually preferable that the above-mentioned unsaturated hydrocarbon compound polymer is contained in the intermediate layer. Note that the intermediate layer may be formed only from the above-mentioned modified product, or may be a mixture with a desired material such as another polymer. However, in the latter case, it is preferable that the modified product is contained in the mixture in an amount exceeding 501% by weight.

Examples of unsaturated hydrocarbon compounds having 4 or more carbon atoms include unsaturated hydrocarbon compounds having 4 carbon atoms such as butadiene, isobutyne, l-butene, and 2-butene, pentene, isoprene, 1,3-pentadiene, and methylbutene. chain unsaturated hydrocarbon compounds with 5 carbon atoms, chain unsaturated hydrocarbon compounds with 6 carbon atoms such as 1-hexene, linear unsaturated hydrocarbon compounds with 7 carbon atoms such as l-heptene, styrene, phenyl Unsaturated hydrocarbon compounds with 8 carbon atoms such as acetylene, unsaturated hydrocarbon compounds with 9 carbon atoms such as α-methylstyrene, indene, and vinyltoluene, and 10 carbon atoms such as α-pinene, β-pinene, and dipentene. Examples include the above-mentioned unsaturated hydrocarbon compounds, and cyclic uncombined hydrocarbon compounds having 5 or 6 carbon atoms such as cyclopentadiene, cyclopentene, and cyclohexene. These unsaturated hydrocarbon compounds may be used alone or in combination.

Examples of modified polymers of unsaturated compounds containing the above-mentioned unsaturated hydrocarbon compounds having 4 or more carbon atoms as main components include unsaturated hydrocarbon compounds having 4 or more carbon atoms, acrylic acid, methacrylic acid, Maleic acid, maleic anhydride, phthalic acid, itaconic acid, derivatives thereof (esters and amides with alcohols or diols), vinyl acetate,
and a copolymer with a monomer containing an oxygen atom selected from vinyl monomers having an epoxy group or a hydroxyl group.

Examples of monomers containing oxygen atoms that can be used for the above modification are detailed below.

Examples of monomer derivatives containing an oxygen atom that can be used to produce the modified product of the present invention include acrylic esters, acrylamides, methacrylic esters, methacrylamides, and allyl compounds.

Examples include vinyl ethers, vinyl esters, vinyl heterocyclic compounds, and N-vinyl compounds.

Specific examples of these compounds include acrylic acids 1 such as acrylic acid, acrylates (e.g.
Methyl acrylate, ethyl acrylate.

Propyl acrylate, butyl acrylate, amyl acrylate, ethylhexyl acrylate, octyl acrylate, 7-octyl acrylate, 2-methoxyethyl acrylate, 2-butoxyethyl acrylate, 2-phenoxyethyl acrylate, chloroethyl acrylate, hydroxy Ethyl acrylate, cyanoethyl acrylate, hydroxypropyl acrylate, dimethylaminoethyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, diethylene glycol monoacrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, 2-hydroxy- 3-chloropropyl acrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, tetrahydrofurfuryl acrylate, phenyl acrylate, etc.): Methacrylic acids 1, such as methacrylic acid, methacrylate (e.g., methyl methacrylate, ethyl methacrylate,
Propyl methacrylate, isopropyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, cyanoacetoxyethyl methacrylate, chlorobenzyl methacrylate, octyl methacrylate, sulfopropyl methacrylate, N-ethyl-N-phenylaminoethyl methacrylate, ethylene glycol mono methacrylate, 2-hydroxyethyl methacrylate,
3-hydroxypropyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate,
2.2-dimethyl-3-hydroxypropyl methacrylate, diethylene glycol monomethacrylate.

Trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, 2-methoxyethyl methacrylate, 2-(3-phenylpropyloxy)
ethyl methacrylate, dimethylaminophenoxyethyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, phenyl methacrylate, talesyl methacrylate, naphthyl methacrylate, etc.) Niacrylamides, e.g. acrylamide.

N-substituted acrylamide (e.g., methylacrylamide,
Ethylacrylamide, propylacrylamide, isopropylacrylamide, butylacrylamide, t-
Butylacrylamide, heptyl acrylamide, t-
Octylacrylamide, cyclohexylacrylamide, benzylacrylamide, hydroxymethylacrylamide, methoxyethylacrylamide, dimethylaminoethylacrylamide, hydroxyethylacrylamide, phenylacrylamide, hydroxyphenylacrylamide, tolylacrylamide, naphthylacrylamide, dimethylacrylamide, diethylacrylamide, dibutylacrylamide, diisobutylacrylamide , diaseptone acrylamide, methylbenzylacrylamide, benzyloxyethylacrylamide, β-cyanoethylacrylamide, acryloylmorpholine, N-methyl-N-acryloylpiperazine, N-acryloylpiperidine.

Acryloylglycine, N-(1,1-dimethyl-3-
hydroxybutyl)acrylamide, N-β-morpholinoethyl acrylamide, N-acryloylhexamethyleneimine, N-hydroxyethyl-N-methylacrylamide, N-2-acetamidoethyl-N-acetylacrylamide): Methacrylamides 2 For example, methacrylamide, N-2
methacrylamide (e.g., methylmethacrylamide,
t-Butyl-methacrylamide.

t-octyl methacrylamide, benzyl methacrylamide, cyclohexyl methacrylamide.

phenylmethacrylamide, dimethylmethacrylamide, diethylmethacrylamide, dipropylmethacrylamide, hydroxyethyl-N-methylmethacrylamide, N-methyl-N-phenylmethacrylamide, N-ethyl-N-phenylmethacrylamide, etc.) Allyl compounds 1 For example, allyl esters (eg.

Allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl valmitate, allyl stearate, allyl benzoate, allyl acetoacetate, allyl lactate, allyl exiethanol, allyl butyl ether, allyl phenyl ether, etc.); Vinyl ethers (Examples: methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethyl butyl ether, Hydroxyethyl vinyl ether, diethylene glycol vinyl ether,
Dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, vinyl phenyl ether, vinyl tolyl ether, vinyl chlorphenyl ether, vinyl-2,4-dichlorophenyl ether, vinyl naphthyl ether, Vinyl esters (e.g., vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl dimethyl propionate, vinyl ethyl butyrate, and vinyl valerate, vinyl caproate, vinyl chloride); Acetate, vinyl dichloroacetate, vinyl methoxy acetate, vinyl butoxy acetate, vinyl phenylacetate, vinyl acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinylcyclohexylcarboxylate, vinyl benzoate,
vinyl salicylate, vinyl chlorobenzoate, vinyl tetrachlorobenzoate, donyl naphthoate, etc.); vinyl heterocyclic compounds (e.g., N-vinyloxazolidone,
(vinylpyridine, vinylpicoline, N-vinylimidazole, N-vinylpyrrolidone, N-vinylcarbazole, vinylthiophene, N-vinylethylacetamide, etc.); Crotonic acids; Compounds containing epoxy groups (e.g., glycidyl acrylate, glycidyl methacrylate, allyl (glycidyl ether, vinyl glycidyl ether, etc.)

In addition, the above monomer may have a substituent such as a halogen.

The above-mentioned modified products are commercially available as, for example, petroleum resins, or can be easily produced according to known olefin polymerization methods.

The modified product used in the present invention has an average molecular weight of 100
It is desirable that the molecular weight is as low as in the range of 10,000 to 10,000, and it is particularly desirable that the average molecular weight is in the range of 300 to 5,000.

The above-mentioned modified products can be made of various known polymeric substances, such as
Polyacrylate resin, polymethacrylate resin,
It may be used in combination with a cellulose resin or the like.

In forming the intermediate layer, first, the above-mentioned modified product is dissolved in a solvent to prepare a coating solution.

Solvents for dissolving modified substances include methanol, ethanol, propatool, butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, diacetone alcohol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, dimethyl formamide. , thinner, etc.

Various additives such as an adhesive enhancer with the substrate, a plasticizer, a lubricant, a matting agent, an antistatic agent, a crosslinking agent, etc. can be added to the modified solution as desired.

This coating solution is applied to the substrate surface (
Alternatively, an intermediate layer can be formed on the substrate (or the undercoat layer) by coating the intermediate layer on the substrate (or the undercoat layer) to form a coating film and then drying it. The thickness of the intermediate layer is 1, usually 0.0
2 to 20 m, preferably 0.05 to 5.0 m
It is le m.

A recording layer is then provided on the intermediate layer.

Examples of materials used for the Q layer include Te, Zn, I
n, Sn, Zr, An, Ti, Cu, Ge, Au, Pt
metalloids such as Bi, As, and Sb; semiconductors such as Ge and Si; and alloys thereof or combinations thereof. In addition, sulfides, oxides, borides, silicon compounds of these metals, semimetals or semiconductors,
Compounds such as carbides and nitrides: and mixtures of these compounds with metals can also be used in the recording layer. Alternatively, a combination of dyes and modifiers can be used.

For the second layer, the above materials were deposited and sputtered.

It can be formed directly on the substrate or via an undercoat layer by a method such as ion blasting. The recording layer may be a single layer or a multilayer, but its layer thickness is generally from lOO to 5,500 mm in terms of optical density required for optical information recording.
It is preferably in the range of 150 to 100OX.

When the recording layer is composed of a combination of a dye and a polymer, the above-mentioned modified product may be used as the polymer.

In this way, an information recording medium in which the substrate, intermediate layer, and recording layer are basically laminated in this order can be manufactured.

In addition, for the purpose of improving mechanical strength, for example, natural polymer substances such as gelatin and gelatin derivatives; cellulose derivatives, polysaccharides, latex-like vinyl polymers, ethylene-vinyl acetate co-modified products, etc. are coated on the recording layer. A protective film made of a synthetic polymer material or the like may be provided.

Further, grooves for laser beam tracking or unevenness representing information such as address signals may be provided in advance on the substrate.A method for providing such grooves and unevenness is to eject from a master disk having grooves or unevenness. There is a method of producing a plastic substrate made of polymethyl methacrylate, polycarbonate, or the like using a molding method. In this case, the intermediate layer according to the present invention is coated on the substrate having grooves and irregularities by the method described above. Another method for providing grooves and unevenness is to provide a coating film made of a photocurable resin between the substrate and the master, photocure it, and then peel off the master (
2P method). In this case, one intermediate layer according to the present invention is prepared in advance by IXI! 1, a photocurable resin is sandwiched between the master and the substrate, and after light irradiation, N51 is peeled off to obtain a structure in which an intermediate layer is provided on the photocurable resin layer.

A typical example of the photocurable ml1li used in the latter method is a mixture of a photopolymerizable monomer (and/or oligomer), a photopolymerization initiator, and the like. As the photopolymerizable monomer (oligomer), known materials such as methacrylic esters and acrylic esters such as ethylene glycol, polyethylene glycol, polypropylene glycol, trimethylolpropane, and pentaerythritol can be used alone or in combination. As the photopolymerization initiator, conventionally known materials such as benzophenone, benzoin alkyl ethers such as benzoin methyl ether, and quinones such as anthraquinone can be suitably used.

On the surface of the substrate opposite to the side on which the recording layer is provided, a thin film made of an inorganic substance such as silicon dioxide, tin oxide, or magnesium fluoride is deposited by vacuum evaporation or sputtering to improve scratch resistance and moisture resistance. etc. may be provided.

Note that the information recording medium of the present invention may be in the form of a bonded type, and this recording medium can be manufactured by bonding two substrates having the above configuration using an adhesive or the like. .

Furthermore, an air sandwich type recording medium is manufactured by joining two disc-shaped substrates, at least one of which has the above configuration, via a ring-shaped outer spacer and a disc-shaped inner spacer. Something will happen. Alternatively, a web-like laser recording medium can be obtained by providing an intermediate layer on a flexible support made of a polyester thin film, and further providing a recording layer and a protective layer.

Next, Examples and Comparative Examples of the present invention will be described.

However, these six examples do not limit the present invention.

[Example 1] Square polyester substrate (locmXl.

cm, thickness: 100 gm) was immersed in isopropyl alcohol for ultrasonic cleaning, and then quickly dried using Preon.

2 g of cyclopentadiene/dicyclopentadiene/cyclopentene/hydroxyethyl methacrylate copolymer [average molecular weight 2800, Finton 1700 (manufactured by Nippon Zeon)] was added from 30 mJl of methyl ethyl ketone, 30 ml of toluene, and 60 mfL of propylene glycol 7-methyl ether. A coating solution for forming an intermediate layer was prepared by dissolving it in a mixed solvent, and this coating solution was coated on the surface of the substrate using a spin coater at a rotation speed of 30 rpm for 10 minutes.
The coating was applied for 2 seconds, and then for 20 seconds at a rotation speed of 800 rpm. This coated layer was dried at 80° C. for 10 minutes to form an intermediate layer having a thickness of 0.21 Lm after drying.

Next, I n f9 (300×) and a GeS layer (240×) were co-deposited on the intermediate layer to form a recording layer having a thickness of 540×.

By the method described above, an information recording medium consisting of a substrate, an intermediate layer made of a modified unsaturated hydrocarbon compound, and a recording layer was manufactured.

[Example 2] Pentene/isoprene/l as a modified substance for forming an intermediate layer
, a substrate, an intermediate layer made of a modified unsaturated hydrocarbon compound, An information recording medium comprising a recording layer and a recording layer was manufactured.

[Example 3] The same procedure as in Example 1 was carried out, except that the same amount of styrene/vinyltoluene/acrylic acid copolymer [average molecular weight: 1400, manufactured by Prioride, Gutdeyer ■] was used as the modified material for forming the intermediate layer. Thus, an information recording medium was produced, which was composed of a substrate, an intermediate layer made of a modified unsaturated hydrocarbon compound, and the Q layer.

[Comparative Example 1] Example 1 except that the same amount of polymethyl methacrylate (Dyanal BR-85, manufactured by Mitsubishi Rayon ■, average molecular weight: 250,000) was used as the modified material for forming the intermediate layer.
In the same manner as above, an information recording medium consisting of a substrate, an intermediate layer made of polymethyl methacrylate, and a recording layer was manufactured.

[Comparative Example 2] Nitrocellulose (RS) was used as a modified material for forming the intermediate layer.
1/2. An information recording medium consisting of a substrate, an intermediate layer made of nitrocellulose, and a recording layer was produced in the same manner as in Example 1, except that the same amount of 1200 (manufactured by Daicel) was used.

[Comparative Example 3] Polystyrene (Himer 5T-95, manufactured by Sanyo Kaisha, Ltd., average molecular weight: 10,000) was used as a modified material for forming the intermediate layer.
An information recording medium composed of a substrate, an intermediate layer made of polystyrene, and a recording layer was manufactured in the same manner as in Example 1, except that the same amount of (A) was used.

[Comparative Example 4] Polystyrene (HIMER 5B7120, manufactured by Sanyo Chemical Co., Ltd., 3 average molecular weight: 2500) was used as a modified material for forming the intermediate layer.
A substrate,
An information recording medium consisting of an intermediate layer made of polystyrene and a recording layer was manufactured.

[Sensitivity evaluation of information recording media] An argon laser (wavelength: 514-5 nm) is focused to a beam system of 25 pm by a lens, and a modulator is used to
An exposure operation was performed by irradiating the obtained information recording medium with a pulse width of 8 Bsec on each side. In this exposure operation, the laser output intensity required to form a groove with a line width of 10 pm in the recording layer was evaluated as the sensitivity of the information recording medium.

Therefore, a recording medium with a low laser output intensity has a high sensitivity.

Margin below The evaluation results are shown in Table 1.

Table 1 Sensitivity (mW) Example 1 85 Example 2 85 Example 3 140 Comparative Example 1 175 Comparative Example 2 175 Comparative Example 3 170 Comparative Example 4 170 As is clear from the results shown in Table 1, this It was confirmed that the information recording medium of the invention (Example 1.2.3) had significantly higher recording sensitivity than the known information recording medium (Comparative Examples 1.2 and 3.4).

[Example 4] A square polyester substrate [10 cm x 10 cm, thickness: 10100 p] was immersed in isopropyl alcohol, ultrasonically cleaned, and then quickly dry-exploded using Freon.

A coating solution for forming an intermediate layer is prepared by dissolving 5 g of butadiene/isobutyne/l-butene/2-butene/hydroxyethyl methacrylate copolymer in a mixed solvent consisting of 60 g of methyl ethyl ketone and 40 g of toluene, and this coating solution is applied to the substrate. Using a spin coater on the surface of
Apply for 10 seconds at rpm, then rotate at 800 rpm.
It was applied for 20 seconds. This coated layer was dried at 80° C. for 10 minutes to form an intermediate layer having a thickness of 0.24 m after drying.

On the surface of the intermediate layer, pentamethine perchlorate dye 0
．． A recording layer forming coating solution prepared by dissolving 6 g of methanol in a mixed solvent of 95 g of methanol and 5 g of dichloromethane was applied using a spin coater for 10 seconds at a rotation speed of 300 rpm, and then for 20 seconds at a rotation speed of 800 rpm. This coating layer was dried at 80° C. for 10 minutes to form a dye recording layer having a thickness of 4 g 0 m after drying.

By the method described above, an information recording medium comprising a substrate, an intermediate layer made of a modified unsaturated hydrocarbon pentahydrogen compound, and a dye recording layer was manufactured.

Claims (1)

[Claims] 1. An information recording medium having a recording layer on a substrate in which information can be written and/or read by a laser via an intermediate layer, wherein the recording layer and/or the intermediate layer has a carbon number of 4. An information recording medium characterized by containing a modified polymer of an unsaturated compound containing the above unsaturated hydrocarbon compound as a main component. 2. A modified polymer of an unsaturated compound containing as a main component an unsaturated hydrocarbon compound having 4 or more carbon atoms, an unsaturated hydrocarbon compound having 4 or more carbon atoms, acrylic acid, methacrylic acid,
maleic acid, maleic anhydride, phthalic acid, itaconic acid,
2. The information recording medium according to claim 1, which is a copolymer of these derivatives, vinyl acetate, and a monomer containing an oxygen atom selected from vinyl monomers having an epoxy group or a hydroxyl group. 3. The information recording medium according to claim 2, wherein the monomer containing an oxygen atom is an ester of methacrylic acid or acrylic acid with a diol, or maleic anhydride. 4. A modified polymer of an unsaturated compound containing as a main component an unsaturated hydrocarbon compound having 4 or more carbon atoms has 100 to 10
2. The information recording medium according to claim 1, wherein the information recording medium has an average molecular weight within the range of 0.000. 5. The modified product of a polymer of an unsaturated compound containing as a main component an unsaturated hydrocarbon compound having 4 or more carbon atoms has 300 to 50 carbon atoms.
2. The information recording medium according to claim 1, wherein the information recording medium has an average molecular weight within a range of 0.000. 6. The information recording medium according to claim 1, wherein the recording layer contains the modified substance. 7. The information recording medium according to claim 1, wherein the intermediate layer contains the above modified substance. 8. The information recording medium according to claim 1, wherein the intermediate layer consists essentially of the above-mentioned modified product.