JPH10330632A - Porphylin compound and optical recording medium using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject rewritable optical recording medium that can be recorded and regenerated with a laser of a specific wavelength range and attracts attention as a high-density recording medium by using a novel porphyrin compound in the recording layer. SOLUTION: The porphyrin compound to be included in the recording layer is represented by formula I (R is an alkyl, naphthyl; X is H, a halogen; m is an integer of 1-8; M means two Hs, a divalent metal or trivalent or tetravalent metal derivative). The compound of formula I is prepared, for example, by thioetherifying a halogensubstituted porphyrin of formula II (Y is halogen, n is an integer of 1-8) with a thiol of the formula: R-SH in the presence of a base in a suitable solvent. The compound of formula I can be used in the recording layer of an optical recording layer and this optical recording medium can be recorded and regenerated with a laser beam selected from 520-690 nm wavelength.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel porphyrin compound and an optical recording medium using the same, which can record and reproduce data at a higher density than conventional ones.

[0002]

2. Description of the Related Art As a recordable optical recording medium conforming to the compact disk (hereinafter abbreviated as CD) standard, a CD-R is used.
(CD-Recordable) has been proposed and developed [for example,
Nikkei Electronics No. 465, p. 10
7, OPTICAL DATA STORAGE, January 23, 1989
DIGEST SERIES vol.1 P45, 1989 etc.]. This CD-R
As shown in FIG. 1, a recording layer 2, a reflective layer 3, and a protective layer 4 are laminated in this order on a transparent resin substrate 1, and the recording layer is irradiated with a high-power laser beam to irradiate the recording layer. Cause physical or chemical changes and record information in the form of pits. By irradiating a low-power laser beam to the formed pit portion and detecting a change in reflectance, pit information can be reproduced. Generally, a near-infrared semiconductor laser having a wavelength of 770 to 830 nm is used for recording / reproducing such an optical recording medium and conforms to CD standards such as Red Book and Orange Book. It has the feature of being compatible with ROM players.

However, the recording capacity of the above-mentioned conventional medium is 6
The capacity is about 50 MB, which is not sufficient when recording moving images, and the demand for higher density and larger capacity of information recording media is increasing with the dramatic increase in the amount of information.

Further, development of short-wavelength semiconductor lasers used for optical disk systems has been advanced, and wavelengths of 680 nm and 6 nm have been developed.
Red semiconductor lasers of 50 nm and 635 nm have been put into practical use [for example, Nikkei Electronics, No. 5
92, p. 65, October 11, 1993]. Record
By shortening the wavelength of the reproduction laser and increasing the numerical aperture of the objective lens, the beam spot can be reduced, and a high-density optical recording medium can be realized. In fact, a large-capacity optical recording medium capable of recording a moving image for a long time has been developed by shortening the wavelength of a semiconductor laser, increasing the numerical aperture of an objective lens, and using data compression technology [for example, Nikkei Electronics, No. 592, p. No. 65, October 11, 1993, No. 594, p. 169, November 8, 1993]. Recently, a digital video disk (DVD) in which a moving image of two hours or more is digitally recorded has been developed. The DVD is a read-only medium having a recording capacity of 4.7 GB, and there is a further demand for the development of a recordable optical disc suitable for this capacity.

[0005] Further, a laser of 532 nm by harmonic conversion of a YAG laser has been practically used.

[0006] Blue / green semiconductor lasers having a wavelength of 490 nm shorter than 532 nm have been studied, but have not yet reached the stage of practical use [for example, Applied Physics].
Letter, P.1272-1274, Vol.59 (1991) and Nikkei Electronics No. 552, p. 90, April 2, 1992
7th issue].

When a short-wavelength laser is used, the linear recording density and the radial recording density of an optical disk can theoretically be increased to the same level, but at present, the recording density in the radial direction must be as large as the linear recording density. It is difficult. Since the laser beam is diffracted and scattered by the groove or the land, the signal detection light amount decreases as the track pitch decreases. Also, there is a molding limitation in reducing the track pitch while maintaining the depth at which a sufficient tracking signal can be obtained. If the groove is deep and narrow, it is difficult to form the recording layer uniformly. Furthermore, the edges of the grooves and lands are not smooth but have minute irregularities, which may cause noise. Such an adverse effect occurs rapidly when the track pitch becomes narrow to some extent. Considering these, the wavelength of 520 nm
When the numerical aperture of the objective lens is 0.6, the limit of the groove pitch is considered to be about 0.5 μm.

When pits are formed by irradiating a dye layer of a write-once optical recording medium with a laser beam to cause a physical change or a chemical change, it is important to determine whether pits having good optical constants and decomposition behavior of the dye can be formed. Element. Those that are difficult to decompose have reduced sensitivity, and those that are severely decomposed or that change easily have a large effect on pits and on lands in the radial direction, making it difficult to form reliable pits. In a conventional CD-R medium, the refractive index of the dye layer is low and the extinction coefficient is not an appropriate value at a laser wavelength used at a high density, so that the reflectance is low and the degree of modulation cannot be obtained. Furthermore, where a small pit should be opened with the focused beam, the influence on the surroundings is large and the pit has a large distribution, and crosstalk in the radial direction is deteriorated. Conversely, the pits became extremely small, and the degree of modulation could not be obtained. Therefore, it is necessary to select an appropriate optical property and decomposition behavior of the dye used for the recording layer.

For example, Japanese Patent Application Laid-Open No. Hei 6-199045 proposes an optical recording medium that can record and reproduce information with a semiconductor laser having a wavelength of 680 nm. Although this medium uses a cyanine dye in the recording layer and shows the possibility of high-density recording / reproduction, there is no description of actually recording at high density.

[0010]

An object of the present invention is to provide a novel porphyrin compound and a porphyrin compound containing the same, having a wavelength of 52 nm.
An object of the present invention is to provide an optical recording medium suitable for high-density recording which can record and reproduce with a short wavelength laser of 0 to 690 nm.

[0011]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. That is, the present invention provides a porphyrin compound represented by the following general formula (1):

[0012]

Embedded image [Wherein, R represents an alkyl group, a phenyl group which may have a substituent, a naphthyl group, X represents a hydrogen atom or a halogen atom, m represents an integer of 1 to 8, and M represents two A hydrogen atom, a divalent metal, or a trivalent or tetravalent metal derivative is shown. ]

In an optical recording medium having at least a recording layer and a reflective layer on a substrate, an optical recording medium containing the porphyrin compound described in the recording layer, the porphyrin compound described in the recording layer, and 60
The optical recording medium according to the above, which contains a light absorbing compound having an absorption maximum in the range of 0 to 900 nm, and the light capable of recording and reproducing with respect to a laser beam selected from the wavelength range of 520 to 690 nm. The recording medium, the optical recording medium having a refractive index of the recording layer of 1.8 or more and the extinction coefficient of 0.04 to 0.4 at the laser wavelength, or a wavelength of 520 to 690 nm. Wherein the reflectance measured from the substrate side to the laser light is 20% or more.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the porphyrin compound of the present invention represented by the general formula (1), the compound in which R is an alkyl group is not particularly limited.
A straight-chain, branched or cyclic alkyl group having 1 to 12 carbon atoms is preferred, and a straight-chain, branched or cyclic alkyl group having 1 to 8 carbon atoms is particularly preferred.

Specific examples of the compounds in which R is an alkyl group include methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, t-butyl, and n-pentyl groups. , Iso-pentyl, 2-methylbutyl, 1-methylbutyl, neo-pentyl, 1,2-dimethylpropyl, 1,
1-dimethylpropyl group, cyclopentyl group, n-hexyl group, cyclohexyl group, 4-methylpentyl group, 3-methylpentyl group, 2-methylpentyl group, 1-methylpentyl group, 3,3-dimethylbutyl group, 2 , 3-dimethylbutyl group, 2,
3-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 1,2-dimethylbutyl, 1,1-dimethylbutyl, 3-ethylbutyl, 2-ethylbutyl, 1- Ethylbutyl group, 1,2,2-triethylbutyl group, 1,1,2-triethylbutyl group, 1-ethyl-2-methylpropyl group, n-heptyl group, 2-methylhexyl group, 3-methylhexyl group, Four-
Methylhexyl group, 5-methylhexyl group, 4-methylcyclohexyl group, 2,4-dimethylpentyl group, n-octyl group, t-octyl group, 2-ethylhexyl group, 2,5-dimethylhexyl group, 2,5 , 5-Trimethylpentyl group, 2,4-dimethylhexyl group, 2,2,4-trimethylpentyl group, 3,5,5-trimethylhexyl group, n-nonyl group, n-decyl group, 4-ethyloctyl group , 4-ethyl-4,5-methylhexyl group, n-undecyl group, n-dodecyl group, 1,3,5,7-tetraethyloctyl group, 4-butyloctyl group, 6,6-diethyloctyl group, n -Pentadecyl group, 3,5-dimethylheptyl group, 2,6-
Dimethylheptyl group, 2,4-dimethylheptyl group, 2,2,5,
5-Tetramethylhexyl group, 1-cyclohexyl-2,2-dimethylpropyl group and the like.

When R is a phenyl group which may have a substituent, examples of such a substituent include an alkyl group having 1 to 6 carbon atoms, and an amino group which may be further substituted with an alkyl group. Can be Specific examples of the phenyl group which may have such a substituent include a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 2-ethylphenyl group,
3-ethylphenyl group, 4-ethylphenyl group, 2,4-dimethylphenyl group, 3,4-dimethylphenyl group, 4-t-butylphenyl group, 4-aminophenyl group, 4-dimethylaminophenyl group, 4 -Diethylaminophenyl group and the like.

Specific examples of X include a hydrogen atom or a halogen atom such as chlorine, bromine, iodine and fluorine.

Specific examples of M include two hydrogen atoms, a metal, and a metal derivative. Examples of M that is a divalent metal include Cu, Zn, Fe, Co, Ni, Ru, Pb, and Pb.
Rh, Pd, Pt, Mn, Sn, trivalent or tetravalent metal derivatives include AlCl, InCl, FeCl, MnC
1, SiCl ₂ , GeCl ₂ , Vo, TiO and the like.

The porphyrin compound of the present invention represented by the general formula (1) can be produced by a one-step or two-step reaction as follows.

For example, in a one-step reaction, a halogen-substituted porphyrin represented by the general formula (2) is reacted with a thiol represented by the general formula (3) in a suitable solvent in the presence of a base to form a thioether. A porphyrin compound represented by the general formula (1) is obtained.

[0021]

Embedded image

R-SH (3) [In the formulas (2) and (3), R and M are the same as those in the formula (1);
Y represents a halogen atom, and n represents an integer of 1 to 8. ]

In the two-step reaction, the above general formula (1)
After once synthesizing a metal-free porphyrin compound in which a metal is not coordinated at the center of the porphyrin compounds represented by the formula, a metal porphyrin compound is obtained by reacting the metal-free porphyrin compound with a metal species in an appropriate solvent. The compound represented by the general formula (2) is not particularly limited, but can be produced, for example, according to the method described in J. Org. Chem., 1996, 61, 3590-3593.

The solvent for the thioetherification may be any solvent which is inert to the thiols represented by the above formula (3), for example, benzene, toluene, xylene,
Nitrobenzene, diglyme, tetraglyme, acetone, methylelketone, acetonitrile, benzonitrile, pyridine, quinoline, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfone, etc. can be used. Preferably, acetone, tetraglyme, quinoline and the like are used.

The amount of the solvent used is 0.5 to 100 times the weight of the halogen-substituted porphyrin, preferably 1 to 5 times.
It is 0 times the weight.

As the base, NaH, NaOH, Na ₂
CO ₃ , KOH, K ₂ CO _{3 and the} like are preferable, and K ₂ CO ₃ is particularly preferable.

The amount of the base used is 0.5 to 100 moles, preferably 1 to 10 moles, per mole of the halogen-substituted porphyrin of the formula (2).

The amount of the thiol represented by the above formula (3) is 0.5 to 1 with respect to the halogen-substituted porphyrin.
The molar amount is 00 times, preferably 1 to 10 times.

The reaction temperature is from 0 to 200 ° C., preferably from 20 to 150 ° C. The reaction time is from 30 minutes to
It is 100 hours, preferably 1 to 50 hours. After the reaction,
The solvent is distilled off from the reaction solution, and the residue is purified by recrystallization or column chromatography to obtain a high-purity target compound.

The metal species used to form the metal complex include Cu, Zn, Fe, Co, Ni, Ru, Pb,
Rh, Pd, Pt, Ti, Mn, Sn, Al, Si, G
e, In, V halides, carboxylic acid derivatives, sulfates, nitrates, carbonyl compounds, oxides, complexes and the like. Preferably, copper chloride, copper acetate, copper (II) acetylacetonate, nickel bromide, nickel acetate, cobalt chloride, cobalt acetate, zinc chloride, zinc acetate, zinc acetate (I
I) acetylacetonate, iron chloride, manganese chloride, manganese (III) acetylacetonate, titanium chloride, vanadium chloride, vanadium oxychloride, palladium chloride, palladium acetate, aluminum chloride, lead chloride, lead acetate, indium chloride, tin chloride It is.

The amount of the metal species used is 0.5 to 50 times, preferably 1 to 10 times the mol of the porphyrins.

The reaction solvent for the two-step reaction may be any solvent that dissolves the metal-free porphyrin compound and the metal species and is inert to the metal-free porphyrin compound and the metal species, such as benzene, toluene, xylene, and chloride. Preferred are methylene, chloroform, carbon tetrachloride, methanol, ethanol, acetone, methyl ethyl ketone, tetrahydrofuran, pyridine, quinoline, N, N-dimethylformamide, N, N-dimethylacetamide, benzonitrile, acetic acid, acetic anhydride and the like. Further, the above solvents may be mixed and used. The amount of the solvent used is 0.5 to 300 times, preferably 1 to 150 times the weight of the metal-free porphyrin.

The reaction temperature is 0 to 200 ° C., preferably 20 to the reflux temperature of the solvent. The reaction time is 3
It is 0 minute to 200 hours, preferably 1 to 100 hours.

After the reaction, the solvent is distilled off from the reaction solution, and the residue is purified by recrystallization or column chromatography to obtain a high-purity target compound.

Preferred specific examples of the porphyrin compound represented by the general formula (1) include compounds having a substituent shown in Table 1.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

[Table 6]

The specific structure of the recording medium of the present invention will be described below. The optical recording medium defined in the present invention refers to both a read-only optical read-only medium on which information is recorded in advance and an optical recording medium capable of recording and reproducing information. Here, as an example, an optical recording medium capable of recording and reproducing the latter information, in particular, an optical recording medium having a recording layer and a reflective layer on a substrate will be described. This optical recording medium has a four-layer structure in which a substrate 1, a recording layer 2, a reflective layer 3, and a protective layer 4 are sequentially laminated as shown in FIG. 1 or a laminated structure as shown in FIG. Have. That is, the recording layer 2 'is formed on the substrate 1',
A reflective layer 3 'is provided in close contact therewith, and a substrate 5' is further bonded thereon via an adhesive layer 4 '. However, another layer may be provided below or above the recording layer 2 ', and another layer may be provided above the reflective layer.

As a material of the substrate, basically, any material may be used as long as it is transparent at the wavelength of the recording light and the reproducing light. For example, an acrylic resin such as a polycarbonate resin, a vinyl chloride resin and polymethyl methacrylate, a polymer material such as a polystyrene resin and an epoxy resin, and an inorganic material such as glass are used. These substrate materials are formed into a disk shape by injection molding or the like. If necessary, guide grooves or pits may be formed on the substrate surface. Such guide grooves and pits are preferably provided at the time of molding the substrate, but may also be provided on the substrate using an ultraviolet curable resin layer. Normal C
When used as the D standard, it has a disk shape with a thickness of about 1.2 mm and a diameter of about 80 to 120 mm, and has a hole with a diameter of about 15 mm in the center.

In the present invention, a recording layer is provided on a substrate, and the recording layer of the present invention has a λmax of 450 to 630 nm.
It contains a porphyrin compound represented by the general formula (1) existing nearby. Above all, an appropriate optical constant (an optical constant is represented by a complex refractive index (n + ki) for a recording and reproducing laser wavelength selected from 520 nm to 690 nm. In the formula, n and k are a real part n and an imaginary part. Here, n is a coefficient corresponding to k. Here, n is a refractive index, and k is an extinction coefficient.)

In general, organic dyes are characterized in that the refractive index n and the extinction coefficient k greatly change with respect to the wavelength λ. n is 1.
If the value is less than 8, the reflectance and the signal modulation required for accurate signal reading cannot be obtained. Even if k exceeds 0.40, the reflectance is reduced and not only a good reproduced signal cannot be obtained. However, the signal tends to change due to the reproduction light, which is not suitable for practical use. In consideration of this feature, by selecting an organic dye having a preferable optical constant at a target laser wavelength and forming a recording layer, a medium having high reflectance and high sensitivity can be obtained. .

The compound represented by the general formula (1) of the present invention has a higher absorption coefficient than ordinary organic dyes, and the absorption wavelength range can be arbitrarily selected by selecting a substituent. Optical constants required for the recording layer at the wavelength (n is 1.8 or more and k is 0.04 to 0.40, preferably, n is 2.0 or more and k is 0.0
It is a very useful compound that satisfies 4-0.20).

The optical recording medium of the present invention has a thickness of 520 nm to 690.
When reproducing with a laser beam selected from nm, it is basically possible if the reflectance is 20% or more, but a reflectance of 30% or more is preferable.

In order to improve the recording characteristics, etc., it has an absorption maximum at a wavelength of 450 to 630 nm, and has an absorption maximum of 520 to 690 nm.
It may be mixed with other dyes having a large refractive index in nm. Specifically, cyanine dyes, squarylium dyes, naphthoquinone dyes, anthraquinone dyes, porphyrin dyes, tetrapyraporphyrazine dyes, indophenol dyes, pyrylium dyes, thiopyrylium dyes, azurenium dyes, tri There are phenylmethane dyes, xanthene dyes, indazulene dyes, indigo dyes, thioindigo dyes, merocyanine dyes, thiazine dyes, acridine dyes, oxazine dyes, etc. Good. The mixing ratio of these dyes is about 0.1 to 30%.

Further, when the optical constant and the imaginary part k are small with respect to the recording and reproducing laser wavelength of the porphyrin compound represented by the general formula (1) selected from 520 nm to 690 nm, the recording characteristics and the like are improved. And a wavelength of 60
You may mix with the light absorption compound which has an absorption maximum in 0-900 nm. Specifically, cyanine dyes, squarylium dyes, naphthoquinone dyes, anthraquinone dyes, porphyrin dyes, tetrapyraporphyrazine dyes, indophenol dyes, pyrylium dyes, thiopyrylium dyes, azurenium dyes, tri There are phenylmethane dyes, xanthene dyes, indathrene dyes, indigo dyes, thioindigo dyes, merocyanine dyes, thiazine dyes, acridine dyes, oxazine dyes, phthalocyanine dyes, naphthalocyanine dyes, and the like. Or a mixture of a plurality of dyes.
The mixing ratio of these dyes is about 0.1 to 30%.

When forming the recording layer, if necessary, a quencher, a dye decomposition accelerator, an ultraviolet absorber, an adhesive, or the like is mixed with the above-mentioned dye, or a compound having such an effect. Can be introduced as a substituent of the dye.

Specific examples of the quencher include metals such as acetylacetonate, bisdithio-α-diketone, bisphenyldithiol, and other bisdithiols, thiocatechol, salicylaldehyde oxime, and thiobisphenolate. Complexes are preferred. Also, amines are suitable.

Examples of the thermal decomposition accelerator include metal compounds such as metal anti-knocking agents, metallocene compounds, and acetylacetonate metal complexes.

Further, if necessary, a binder, a leveling agent, an antifoaming agent and the like can be used in combination. Preferred binders include polyvinyl alcohol, polyvinylpyrrolidone, nitrocellulose, cellulose acetate, ketone resin, acrylic resin, polystyrene resin, urethane resin, polyvinyl butyral, polycarbonate, polyolefin and the like.

When the recording layer is formed on the substrate, a layer made of an inorganic substance or a polymer may be provided on the substrate in order to improve the solvent resistance, the reflectance, the recording sensitivity and the like of the substrate.

Here, the content of the porphyrin compound represented by the general formula (1) in the recording layer is 30% or more, preferably 60% or more. In addition, it is also preferable that it is substantially 100%.

Examples of the method for providing the recording layer include coating methods such as spin coating, spraying, casting, and dipping.
Examples include a sputtering method, a chemical vapor deposition method, and a vacuum vapor deposition method, and a spin coating method is simple and preferred.

When a coating method such as a spin coating method is used, the porphyrin compound represented by the general formula (1)
A coating solution dissolved or dispersed in a solvent is used in an amount of 40% by weight, preferably 3 to 30% by weight. At this time, it is preferable to select a solvent that does not damage the substrate. For example, methanol, ethanol, isopropyl alcohol, octafluoropentanol, allyl alcohol, methyl cellosolve, ethyl cellosolve, alcohol solvents such as tetrafluoropropanol, hexane, heptane, octane, decane, cyclohexane,
Aliphatic or alicyclic hydrocarbon solvents such as methylcyclohexane, ethylcyclohexane, and dimethylcyclohexane; aromatic hydrocarbon solvents such as toluene, xylene, and benzene; and halogenation such as carbon tetrachloride, chloroform, tetrachloroethane, and dibromoethane. Hydrocarbon solvents, ether solvents such as diethyl ether, dibutyl ether, diisopropyl ether, dioxane, acetone,
Examples thereof include ketone solvents such as hydroxy-3-methyl-2-butanone, ester solvents such as ethyl acetate and methyl lactate, and water. These may be used alone or as a mixture of two or more. If necessary, the dye of the recording layer can be dispersed in a polymer thin film or the like.

When a solvent that does not damage the substrate cannot be selected, a sputtering method, a chemical vapor deposition method, a vacuum vapor deposition method, or the like is effective.

The thickness of the dye layer is not particularly limited, but is preferably 50 to 300 nm. If the thickness of the dye layer is less than 50 nm, recording cannot be performed due to large thermal diffusion, or a recording signal will be distorted and the signal amplitude will be small. On the other hand, when the film thickness is larger than 300 nm, the reflectivity decreases and the reproduction signal characteristics deteriorate.

Next, on the recording layer, preferably, a thickness of 50
A reflective layer of ~ 300 nm is formed. As a material of the reflection layer, a material having a sufficiently high reflectance at the wavelength of the reproduction light, for example, A
u, Al, Ag, Cu, Ti, Cr, Ni, Pt, T
The metals a, Cr and Pd can be used alone or as an alloy. Among them, Au, Al and Ag have high reflectivity and are suitable as a material for the reflective layer. In addition, the following may be included. For example, Mg, S
e, Hf, V, Nb, Ru, W, Mn, Re, Fe, C
o, Rh, Ir, Zn, Cd, Ga, In, Si, G
Metals and metalloids such as e, Te, Pb, Po, Sn, and Bi can be mentioned. Further, those containing Au as a main component are preferable because a reflection layer having high reflectance can be easily obtained. Here, the main component means a component having a content of 50% or more. It is also possible to form a multilayer film by alternately stacking low-refractive-index thin films and high-refractive-index thin films with a material other than a metal, and use it as a reflective layer.

As a method of forming the reflection layer, for example,
Examples include a sputtering method, an ion plating method, a chemical vapor deposition method, and a vacuum vapor deposition method. In addition, a known inorganic or organic intermediate layer or adhesive layer may be provided on the substrate or below the reflective layer to improve the reflectance, the recording characteristics, and the adhesion.

The material of the protective layer on the reflective layer is not particularly limited as long as it protects the reflective layer from external force. As organic substances, thermoplastic resins, thermosetting resins,
An electron beam curable resin, a UV curable resin, and the like can be given. As the inorganic substance, SiO ₂ , Si ₃ N ₄ ,
MgF ₂ , SnO _{2 and the} like can be mentioned. Thermoplastic resin, thermosetting resin, etc. are dissolved in an appropriate solvent and a coating liquid is applied,
It can be formed by drying. The UV curable resin can be formed by preparing a coating solution as it is or by dissolving it in an appropriate solvent, applying the coating solution, and irradiating with UV light to cure the resin. UV
As the curable resin, for example, urethane acrylate,
Acrylate resins such as epoxy acrylate and polyester acrylate can be used. These materials may be used alone or as a mixture, or may be used as a multilayer film as well as a single layer.

As a method of forming the protective layer, a coating method such as a spin coating method or a casting method, a sputtering method, a chemical vapor deposition method, or the like is used as in the case of the recording layer. Of these, the spin coating method is preferable.

The thickness of the protective layer is generally from 0.1 to 100.
μm, but in the present invention, 3 to 30 μm
And more preferably 5 to 20 μm. Printing of a label or the like can be further performed on the protective layer.

Alternatively, a protective sheet or a substrate may be bonded to the reflective layer surface, or two optical recording media may be bonded with the reflective layer surfaces facing each other. An ultraviolet curable resin, an inorganic thin film, or the like may be formed on the mirror surface of the substrate to protect the surface or prevent adhesion of dust and the like.

The laser having a wavelength of 520 to 690 nm referred to in the present invention is not particularly limited. For example, a dye laser capable of selecting a wavelength in a wide range of the visible region, a helium neon laser having a wavelength of 633 nm, and a recently developed wavelength of 68 can be used.
A high-power semiconductor laser near 0, 650, and 635 nm;
A harmonic conversion YAG laser having a wavelength of 532 nm may be used. According to the present invention, high-density recording and reproduction can be performed at one wavelength or a plurality of wavelengths selected from these.

[0067]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1 Synthesis of compound (18) 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrin (hereinafter referred to as H ₂ OBP) 5
g, thiophenol 5.5 g, potassium carbonate 6.9 g,
100 ml of acetone is mixed under a nitrogen atmosphere, and 25 to 30
Stirred at C for 20 hours. Acetone was distilled off, 200 ml of toluene was added, extraction was performed, water washing and filtration were performed, and then the solvent was distilled off. The residue was purified by column chromatography (silica gel / toluene) to give Compound (18) 10.
3 g were obtained as a deep green glossy powder. It was confirmed to be the target substance from the following analysis results.

[0069]

Table 7 Elemental analysis _{(C 74 H 47 N 4 Br} 3 S 5):

The compound thus obtained showed a maximum absorption at 489 nm in a chloroform solution, and its gram extinction coefficient was 8.74 × 10 ⁴ ml / g. cm.

Example 2 Synthesis of Compound (19) 12.5 g of H ₂ OBP, 8.8 g of thiophenol, 11.0 g of potassium carbonate and 100 ml of acetone were mixed under a nitrogen atmosphere, and the mixture was stirred at 25 to 30 ° C. for 20 hours. Acetone was distilled off, 200 ml of toluene was added, extraction was performed, water washing and filtration were performed, and then the solvent was distilled off. The residue was purified by column chromatography (silica gel / toluene) to obtain 11.8 g of compound (19) as a reddish brown powder. It was confirmed to be the target substance from the following analysis results.

[0072]

Table 8 Elemental analysis _{(C 92 H 62 N 4 S} 8):

The compound thus obtained shows a maximum absorption at 523 nm in a chloroform solution, and has a gram extinction coefficient of 5.91 × 10 ⁴ ml / g. cm.

Example 3 Synthesis of Compound (30) Compound (18) 3.0 under a nitrogen atmosphere at 25 to 30 ° C.
g, chloroform 150 ml, and then zinc (II)
1.0 g of acetylacetonate monohydrate and methanol 6
0 ml of the solution was added and refluxed for 90 hours. After cooling, the mixture was washed with water, filtered, and the solvent was distilled off. The residue was purified by column chromatography (silica gel / toluene) to obtain 2.4 g of compound (30) as a dark green powder.

From the following analysis results, the product was confirmed to be the target product. In addition, in this example and the following examples, the metal was confirmed by the atomic absorption method.

[0076]

TABLE 9 Elemental analysis _{(C 74 H 45 N 4 Br} 3 S 5 Zn):

The compound thus obtained exhibits a maximum absorption of 523 nm in a chloroform solution, and has a gram extinction coefficient of 1.08 × 10 ⁵ ml / g. cm.

Example 4 Synthesis of Compound (43) Compound (18) 3.0 under a nitrogen atmosphere at 25 to 30 ° C.
g, 150 ml of toluene, and a solution of 0.6 g of copper (II) acetate monohydrate and 50 ml of methanol was added.
Refluxed for hours. After cooling, the mixture was washed with water, filtered, and the solvent was distilled off. The residue was purified by column chromatography (silica gel / toluene) to obtain 2.2 g of compound (43) as a reddish brown powder. It was confirmed to be the target substance from the following analysis results.

[0079]

TABLE 10 Elemental analysis _{(C 74 H 45 N 4 Br} 3 S 5 Cu):

The compound thus obtained exhibits a maximum absorption at 530 nm in a chloroform solution, and has a gram extinction coefficient of 1.01 × 10 ⁵ ml / g. cm.

Example 5 Synthesis of Compound (31) Compound (19) 3.0 was prepared at 25-30 ° C. under a nitrogen atmosphere.
g, 150 ml of toluene, 1.0 g of zinc (II) acetylacetonate monohydrate and 60 ml of methanol.
of solution was added and refluxed for 90 hours. After cooling, the mixture was washed with water, filtered, and the solvent was distilled off. The residue was purified by column chromatography (silica gel / toluene) to give compound (3)
1) 2.4 g was obtained as a deep blue powder. It was confirmed to be the target substance from the following analysis results.

[0082]

TABLE 11 Elemental analysis _{(C 92 H 60 N 4 S} 8 Zn):

The compound thus obtained exhibits a maximum absorption of 598 nm in a chloroform solution, and has a gram extinction coefficient of 7.92 × 10 ⁴ ml / g. cm.

Example 6 Synthesis of Compound (44) Compound (19) 3.0 was prepared at 25-30 ° C. under a nitrogen atmosphere.
g, 150 ml of toluene, and a solution of 0.6 g of copper (II) acetate monohydrate and 50 ml of methanol was added.
Refluxed for hours. After cooling, the mixture was washed with water, filtered, and the solvent was distilled off. The residue was purified by column chromatography (silica gel / toluene) to obtain 2.3 g of compound (44) as a brown powder. It was confirmed to be the target substance from the following analysis results.

[0085]

TABLE 12 Elemental analysis _{(C 92 H 60 N 4 S} 8 Cu):

The compound thus obtained exhibits a maximum absorption at 606 nm in a chloroform solution, and has a gram extinction coefficient of 7.94 × 10 ⁴ ml / g. cm.

Example 7 Synthesis of Compound (86) Under a nitrogen atmosphere, 3.0 g of Compound (18) and 1.9 g of manganese chloride tetrahydrate were dissolved in a mixed solvent of 300 ml of glacial acetic acid and 90 ml of acetic acid. After stirring for 4 hours and allowing to cool, the solvent was distilled off in vacuo. The residue was purified by column chromatography (silica gel / toluene) to give compound (8).
6) 1.8 g were obtained as a brown powder. It was confirmed to be the target substance from the following analysis results.

[0088]

[Table 13] Elemental analysis value (C ₇₄ H ₄₅ N ₄ Br ₃ S ₅ MnC
l):

The compound thus obtained exhibited a maximum absorption at 562 nm in a chloroform solution, and had a gram extinction coefficient of 9.16 × 10 ⁴ ml / g. cm.

Example 8 Among the porphyrin compounds represented by the general formula (1), 0.2 g of the compound (18) was added to 10 m of dimethylcyclohexane.
1 to prepare a dye solution. The substrate is made of a continuous guide groove made of polycarbonate resin (track pitch: 0.
8 μm) with a diameter of 120 mmφ and a thickness of 1.2 mm.

The dye solution was placed on the substrate at a rotational speed of 1500 r.
pm, and dried at 70 ° C. for 3 hours to form a recording layer. The absorption maximum of this recording layer is 568 nm, and the optical constants are n = 2.1 and k = 0.04 at 680 nm, and n = 2.3 and k = 0.3 at 650 nm.
08, n is 2.4 and k is 0.10 at 635 nm.
It is.

Au was sputtered on the recording layer by using a sputtering apparatus (CDI-900) manufactured by Balzers to form a reflective layer having a thickness of 100 nm. Sputter gas includes
Argon gas was used. The sputtering conditions were as follows: a sputtering power of 2.5 kW and a sputtering gas pressure of 1.0 × 10 ⁻² Torr.
I went in.

Further, a UV-curable resin SD-1 is provided on the reflective layer.
After spin-coating 7 (manufactured by Dainippon Ink and Chemicals),
A protective layer having a thickness of 6 μm was formed by irradiating ultraviolet rays to produce an optical recording medium.

An optical disc evaluation apparatus (DDU- manufactured by Pulstec Industrial) equipped with a semiconductor laser head having a wavelength of 635 nm and a lens numerical aperture of 0.6 on the obtained optical recording medium.
1000) and a KENWOOD EFM encoder so that the linear velocity was 3.5 m / s, the laser power was 8 mW, and the shortest pit length was 0.44 μm. After recording, signals were reproduced using an evaluation device equipped with 650 nm and 635 nm red semiconductor laser heads (the numerical aperture of the lens was 0.6), and the reflectance, error rate, and modulation were measured. The value was shown.

Next, an optical disk evaluation device (DDU) manufactured by Pulstec Industrial equipped with a 680 nm semiconductor laser head
-1000) and KENWOOD EFM encoder, linear velocity 1.4m / s, laser power 10m
W was recorded so that the shortest pit length was 0.60 μm.
The recorded medium was stored at 680 nm, 650 nm and 635 nm.
The signal was reproduced using an optical disk evaluation device (DDU-1000) manufactured by Pulstec Industrial equipped with a nm red semiconductor laser head, and the reflectance, the error rate, and the modulation were measured. All exhibited good values.

As described above, this medium was able to perform recording and reproduction satisfactorily with a plurality of laser wavelengths. In addition, the error rate is a CD decoder manufactured by Kenwood (DR35).
52), and the degree of modulation was determined by the following equation.

Modulation degree = {(maximum signal strength) − (minimum signal strength)} / (maximum signal strength)

Example 9 A substrate made of a polycarbonate resin and having a continuous guide groove (track pitch: 0.8 μm) having a diameter of 120 mmφ,
Example 8 except that a disc having a thickness of 0.6 mm was used.
A coating and a reflection layer were formed in the same manner as described above.

Further, an ultraviolet-curable adhesive SD-
301 (made by Dainippon Ink and Chemicals),
On top of that, it is made of polycarbonate resin and has a diameter of 120 mmφ,
An optical recording medium was prepared in which a disc-shaped substrate having a thickness of 0.6 mm was placed, and then irradiated with ultraviolet rays and bonded.

An optical disk evaluation device (DDU-1000) manufactured by Pulstec Industrial and an EFM encoder manufactured by KENWOOD were used in the same manner as in Example 8 except that a 635 nm semiconductor laser head corresponding to a thickness of 0.6 mm was mounted on the manufactured medium. And recorded. After recording, the signal was reproduced using an evaluation device equipped with 650 nm and 635 nm red semiconductor laser heads, and the reflectance, error rate, and modulation were measured.

Examples 10 to 15 The porphyrin compounds described in Table 1 [(19), (3)
0), (31), (43), (44), and (86)], except that the optical recording medium was manufactured in the same manner as in Example 9. In the same manner as in Example 9, recording was performed on the produced medium using an optical disk evaluation device (DDU-1000) manufactured by Pulstec Industrial Co., Ltd. equipped with a 635 nm semiconductor laser head and an EFM encoder manufactured by KENWOOD. After recording, 650
The signals were reproduced using an evaluation device equipped with a red semiconductor laser head of 635 nm and 635 nm, and the reflectance, the error rate, and the modulation were measured.

Example 16 In the same manner as in Example 9 except that the compound (18) and diacetone alcohol were used as a coating solvent, an optical disk evaluation device (DDU-1000) manufactured by Pulstec Industrial equipped with a 635 nm semiconductor laser head and EFM manufactured by KENWOOD were used. Recorded using an encoder. After recording, the signal was reproduced using an evaluation device equipped with 650 nm and 635 nm red semiconductor laser heads, and the reflectance, error rate, and modulation were measured.

Comparative Example 1 In Example 9, a pentamethine cyanine dye NK2929 [1,3,3,1 ′, 3 ′, 3 ′) was used in place of the porphyrin compound.
-Hexamethyl-2 ', 2'-(4,5,4 ', 5'-dibenzo) indodicarbocyanine perchlorate, manufactured by Japan Photographic Dye Laboratories
An optical recording medium was produced in the same manner except that the above was used.
An optical disk evaluation device (DDU-1000) manufactured by Pulstec Industrial and a EF manufactured by KENWOOD equipped with a 635 nm semiconductor laser head mounted on the manufactured medium in the same manner as in Example 9.
Recording was performed at a linear velocity of 3.5 m / s and a laser power of 7 mW using an M encoder. After recording, 650 nm and 6
As a result of reproducing a signal using an evaluation device equipped with a 35 nm red semiconductor laser head, the reflectance was low, the error rate was large, and the modulation was small. The signal was degraded when playing for a longer time.

Comparative Example 2 In Comparative Example 1, instead of NK2929, a trimethine cyanine dye NK79 [1,3,3,1 ′, 3 ′, 3′-hexamethyl-
2 ′, 2′-Indodicarbocyanine iodide, manufactured by Japan Photographic Dye Laboratories Co., Ltd.]. 635 in the same manner as in Example 9
optical disk evaluation device (DDU-1000) manufactured by Pulstec Industrial and equipped with KEN
Using a WOOD EFM encoder, a linear velocity of 3.5
m / s and recording with a laser power of 7 mW. After recording, 6
When a signal was reproduced using an evaluation device equipped with a 50 nm and 635 nm red semiconductor laser head, the waveform was distorted, the error rate was large, and the modulation was small. The signal was degraded when playing for a longer time.

In the above Examples 8 to 16 and Comparative Examples 1 and 2, the optical constant of the recording layer and the reflectance, error rate, and modulation when recording each medium at 635 nm and reproducing at 650 nm and 635 nm are shown. Table 2 summarizes them.

[0106]

[Table 14] Table-2 * 1 n; refractive index * 2 k; extinction coefficient

[0107]

[Table 15] Table-2 (continued) * 1 n; refractive index * 2 k; extinction coefficient

[0108]

By using the porphyrin compound of the present invention in the recording layer, a write-once optical recording medium capable of recording and reproducing with a laser having a wavelength of 520 to 690 nm, which is attracting much attention as a high-density optical recording medium, is provided. It is possible to do.

[Brief description of the drawings]

FIG. 1 is a schematic sectional structural view showing a conventional optical recording medium and a layer configuration of the present invention.

FIG. 2 is a schematic sectional structural view showing a layer configuration of the optical recording medium of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Recording layer 3 Reflective layer 4 Protective layer 1 'substrate 2' Recording layer 3 'Reflective layer 4' Adhesive layer 5 'Substrate

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yojiro Kumagai 1-43, Minami, Yuge-cho, Yao-shi, Osaka Yamamoto Kasei Co., Ltd. (72) U. Tsukahara 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemicals Inside the company (72) Inventor Denmi Misawa 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Inside of Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Keisuke Takuma 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemicals

Claims (6)

[Claims] 1. A porphyrin compound represented by the following general formula (1). Embedded image [Wherein, R represents an alkyl group, a phenyl group which may have a substituent, a naphthyl group, X represents a hydrogen atom or a halogen atom, m represents an integer of 1 to 8, and M represents two A hydrogen atom, a divalent metal, or a trivalent or tetravalent metal derivative is shown. ] 2. An optical recording medium having at least a recording layer and a reflective layer on a substrate, wherein the recording layer contains the porphyrin compound according to claim 1. 3. The optical recording medium according to claim 2, wherein the recording layer contains the porphyrin compound according to claim 1 and a light absorbing compound having an absorption maximum in a range of 600 to 900 nm. 4. The optical recording medium according to claim 2, wherein recording and reproduction can be performed with respect to a laser beam selected from a wavelength range of 520 to 690 nm. 5. The optical recording medium according to claim 2, wherein, at the laser wavelength, the recording layer has a refractive index of 1.8 or more and an extinction coefficient of 0.04 to 0.4. 6. The optical recording medium according to claim 2, wherein the reflectance measured from the substrate side to the laser beam selected from the wavelength range of 520 to 690 nm is 20% or more.