JP2001214084A - Metal chelate pigment and optical recording medium using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coloring material that can be used as an optical recording medium suitable for record regeneration with the short-wavelength semiconductor laser. SOLUTION: The objective metal chelate coloring material comprises a metal and a compound represented by the following general formula (1) or (1)' (wherein A and A' are each a heteroaromatic ring residue involving the carbon atoms and nitrogen atoms bonding to these A and A'; X is a group having an active hydrogen atom; Y is a hydrogen atom or an arbitrary substituent).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal chelate dye and a write-once optical recording medium using such a dye for a recording layer, and more particularly to a write-once optical recording medium for a blue laser.

[0002]

2. Description of the Related Art In recent years, semiconductor lasers having a short oscillation wavelength have been developed, and the wavelength of a conventionally used laser has been reduced to 78 nm.
There is a demand for an optical recording medium capable of high-density recording and reproduction using laser light having a wavelength shorter than 0 nm and 830 nm. Conventionally proposed optical recording media include magneto-optical recording media,
There are a phase change recording medium, a chalcogen oxide optical recording medium, an organic dye optical recording medium, and the like. Among these, the organic dye optical recording medium is inexpensive in cost and easy in the manufacturing process. Is considered to have an advantage.

At present, writable compact discs (CD-R) of a type in which a metal layer having a high reflectance is laminated on an organic dye layer have been mass-produced and widely known as organic dye-based optical recording media. A high-density organic dye-based optical recording medium (DVD-R) for recording with a red semiconductor laser having a shorter wavelength than the laser used for recording and reproduction of the CD-R.
R) has also been developed and put into practical use. However, as laser oscillation at shorter wavelengths becomes possible, lasers with shorter wavelengths than DVD-Rs aiming at even higher densities, ie, blue semiconductor lasers (wavelengths from 350 nm to 530 nm) will be used in the future.
The need for an optical recording medium capable of recording / reproducing at nm) is increasing.

[0004]

Generally, an optical recording medium used as a CD-R or DVD-R has a problem that, when recording and reproducing with a short-wavelength blue semiconductor laser, the reflectivity is low and recording and reproducing cannot be performed. Have. An object of the present invention is to provide a dye suitable for an organic dye-based optical recording medium that can be recorded and reproduced by a blue semiconductor laser, and an optical recording medium using the same.

[0005]

As a result of various studies on organic dyes having high sensitivity to a blue semiconductor laser, the present inventors have found a novel metal chelate dye comprising an azo compound containing an isothioxazole ring and a metal, and have found this dye. Can be used for a recording layer of an optical recording medium corresponding to a blue semiconductor laser, and arrived at the present invention. That is, the gist of the present invention is represented by the following general formula (1) or (1) ′

[0006]

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(In the formulas (1) and (1) ′, A and A ′ represent a heteroaromatic ring residue containing a carbon atom and a nitrogen atom to which they are bonded, and X represents a group having an active hydrogen atom. And Y
Represents a hydrogen atom or an optional substituent. ) And a metal chelate dye comprising a metal and an optical recording medium containing the dye in a recording layer.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The metal chelate dye of the present invention comprises an azo compound represented by the general formula (1) or (1) ′ and a metal. In the general formulas (1) and (1) ′, the heteroaromatic ring residue represented by A and A ′ is selected from a wide range as long as the heterocyclic ring contains a carbon atom and a nitrogen atom to which it is bonded.
Usually, a 5- to 6-membered heteroaromatic ring and a condensed ring of such a heteroaromatic ring and a benzene ring are exemplified, and the following heterocycles are preferred.

[0009]

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In the above formulas (a) to (d), D _{1 to} D ₄₂ each independently represent a hydrogen atom; methyl, ethyl, n-propyl, isopropyl, n-butyl, sec- A linear or branched alkyl group having 1 to 6 carbon atoms such as a butyl group or a tert-butyl group; a trifluoromethyl group, a pentafluoromethyl group, a 2-fluoroethyl group, a 2,2-difluoroethyl group, , 2-trifluoroethyl group, 2H-tetrafluoroethyl group, heptafluoro-
n-propyl group, 3,3,3-trifluoropropyl group, 1H, 1H-pentafluoropropyl group, 1H, 1
H, 3H-tetrafluoropropyl group, perfluoro-
n-butyl group, 1- (trifluoromethyl) tetrafluoroethyl group, 1- (trifluoromethyl) -2,2,
2-trifluoroethyl group, 1- (trifluoromethyl) ethyl group, 1- (difluoromethyl) -2,2-difluoromethyl group, 1- (fluoromethyl) -2-trifluoroethyl group, perfluoro-1 , 1-dimethylethyl group, 1,1-di (trifluoromethyl) ethyl group,
1- (trifluoroethyl) -1-methylethyl group, 1
A linear or branched alkyl fluoride group having 1 to 6 carbon atoms such as -methyl-1H-perfluoropropyl group, 1-methyl-1H-perfluorobutyl group; trifluoromethoxy group, pentafluoromethoxy group, 2- Fluoroethoxy group, 2,2-difluoroethoxy group, 2,2,2-trifluoroethoxy group, 2H-tetrafluoroethoxy group, heptafluoro-n-propoxy group, 3,3,3-
Trifluoropropoxy group, perfluoro-n-butoxy group, 1H, 1H-heptafluorobutoxy group, 1-
(Trifluoromethyl) -2,2,2-trifluoroethoxy group, 1- (trifluoromethyl) -tetrafluoroethoxy group, 1- (difluoromethyl) -2,2-difluoroethoxy group, 1-methyl-1H A linear or branched fluorinated alkoxy group having 1 to 6 carbon atoms, such as a perfluoropropoxy group, a 1-methyl-1H-perfluorobutoxy group, a 2,2-di (trifluoromethyl) propoxy group; a cyclopropyl group , A cycloalkyl group having 3 to 6 carbon atoms such as a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group;

An aryl group having 6 to 18 carbon atoms such as a phenyl group, a tolyl group, a xylyl group, a mesityl group and a naphthyl group;
Methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, te
1 carbon atom such as rt-butoxy group and n-pentyloxy group
An alkyl group having 2 to 7 carbon atoms such as an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a valeryl group, an isovaleryl group, a pivaloyl group; a vinyl group, a propenyl group, a butenyl group, a pentenyl group; A linear or branched alkenyl group having 2 to 6 carbon atoms such as a hexenyl group; a cyclic alkenyl group having 3 to 6 carbon atoms such as a cyclopentenyl group or a cyclohexenyl group; a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom Formyl group; hydroxyl group; carboxyl group; hydroxyalkyl group having 1 to 6 carbon atoms such as hydroxymethyl group and hydroxyethyl group; methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, isopropoxycarbonyl group, n- Butoxycarbonyl group, sec-butoxycarbonyl group C2-C7 alkoxycarbonyl groups such as tert-butoxycarbonyl group; nitro group; cyano group; amino group; methylamino group, ethylamino group, n-propylamino group, n-butylamino group, dimethylamino group, C1-C10 alkylamino groups such as diethylamino group and di-n-propylamino group; methoxycarbonylmethyl group, methoxycarbonylethyl group, ethoxycarbonylmethyl group, n-propoxycarbonylethyl group, isopropoxycarbonylmethyl group, etc. C3-7 alkoxycarbonylalkyl group; carbon number such as methylthio group, ethylthio group, n-propylthio group, isopropylthio group, n-butylthio group, sec-butylthio group, tert-butylthio group and n-pentylthio group 1-6 alkylthio groups; trif Oromechiruchio group, pentafluoroethyl methyl thio group, 2-fluoroethyl-thio group, 2,2-difluoroethyl thio group, 2H-
Tetrafluoroethylthio, heptafluoro-n-propylthio, 3,3,3-trifluoropropylthio, perfluoro-n-butylthio, 1H, 1H, 3
H-hexafluorobutylthio group, 1- (trifluoromethyl) tetrafluoroethylthio group, 1- (trifluoromethyl) -2,2,2-trifluoroethylthio group, 1- (ditrifluoromethyl) -2 , 2-difluoroethylthio, perfluoro-1,1-dimethylethylthio, 1-methyl-1H-perfluoropropylthio, 1-methyl-1H-perfluorobutyl, 2,
2-di (trifluoromethyl) propylthio group, 3-
A linear or branched fluorinated alkylthio group having 1 to 6 carbon atoms such as (perfluoro-1-methylethyl) propylthio group;

C.sub.1 -C.sub.1 groups such as methylsulfonyl, ethylsulfonyl, n-propylsulfonyl, isopropylsulfonyl, n-butylsulfonyl, sec-butylsulfonyl, tert-butylsulfonyl and n-pentylsulfonyl; 6, an alkylsulfonyl group; a trifluoromethylsulfonyl group, a pentafluoroethylsulfonyl group, a 2-fluoroethylsulfonyl group, a 2,2-difluoroethylsulfonyl group,
2-trifluoroethylsulfonyl group, heptafluoro-n-propylsulfonyl group, 3,3,3-trifluoropropylsulfonyl group, 1H, 1H, 3H-tetrafluoropropylsulfonyl group, perfluoro-n-butylsulfonyl group, 1H, 1H-heptafluorobutylsulfonyl group, 2- (perfluorobutyl) ethylsulfonyl group, 1- (trifluoromethyl) tetrafluoroethylsulfonyl group, 1- (trifluoromethyl) -2,
2,2-trifluoroethylsulfonyl group, 1- (difluoromethyl) -2,2-difluoroethylsulfonyl group, perfluoro-1,1-dimethylethylsulfonyl group, 1- (trifluoroethyl) -1-methylethyl Sulfonyl group, 1-methyl-1H-perfluoropropylsulfonyl group, 1-methyl-1H-perfluorobutylsulfonyl group, 2,2-di (trifluoromethyl) propylsulfonyl group, 3- (perfluoro-1-methyl) ethyl) propylsulfonyl linear or branched fluorinated alkyl sulfonyl group having 1 to 6 carbon atoms such as group; an alkoxy group as a substituent, an alkyl fluoride group, an aryl group or an aryl group having a halogen atom or the like; -CD ₄₃
ＣC (CN) D ₄₄ (D ₄₃ is a hydrogen atom, or D ₁ to
D represents an alkyl group having 1 to 6 carbon atoms as defined for D ₄₂ , D ₄₄ represents a cyano group or an alkoxycarbonyl group having 2 to 7 carbon atoms similar to those defined for D _{1 to} D ₄₂ above . ). Further, among D _{1 to} D ₄₂ , adjacent groups may be bonded to form a ring condensed with ring A or ring A ′.

The substituents D _{1 to} D ₄₂ of the rings A and A ′ are preferably a hydrogen atom, an unsubstituted or halogenated alkyl group, an unsubstituted or halogenated alkyl group, although they may vary depending on the structures of the rings A and A ′. Alkylthio group, unsubstituted or halogenated alkoxy group, formyl group, cyano group, nitro group, hydroxyl group or halogen atom. In this case, fluorine is preferable as the halogen.
Of the 17 types of rings exemplified as ring A or ring A ′,
More preferred are an oxazole ring [(a), (b)], a pyrazole ring [(c)], an imidazole ring [(d)], an isoxazole ring [(e)], a thiadiazole ring [(f), (g). )]
And a triazole ring [(h), (li), (nu)].

In the general formulas (1) and (1) ′, X is a group having an active hydrogen atom such as a hydroxyl group, an amino group, a sulfonic acid group, a carboxyl group, an alkylsulfonylamino group and a thiol group. Preferred are a hydroxyl group, a sulfonic acid group and an amino group, and particularly preferred is a hydroxyl group.

Y represents a hydrogen atom or an optional substituent.
As such a substituent, for example, a linear or linear C 1-12 group
A branched alkyl group; a cyclic alkyl group having 3 to 12 carbon atoms;
A linear or branched alkenyl group having 2 to 12 carbon atoms; carbon number
3 to 12 cyclic alkenyl groups; aryl having 6 to 18 carbon atoms
A linear or branched alkylcarbo having 2 to 12 carbon atoms
Nyl group; linear or branched alkoxy having 1 to 12 carbon atoms
A linear or branched alkylthio group having 1 to 12 carbon atoms
A linear or branched fluoroalkyl having 1 to 12 carbon atoms
A straight-chain or branched fluoroal having 1 to 12 carbon atoms
Coxy group; C1-C12 linear or branched fluoro
Alkylthio group; halogen atom; nitro group; cyano group;
Hydroxy group; formyl group; sulfonic acid group; carboxy
A group; -NR₁R_TwoAn amino group represented by the formula: -NHCOR_Three
An acylamino group represented by the formula: -NHCOOR_FourRepresented by
Carbamate group; -NHSO_TwoR_FiveSulfone represented by
Amide group; -COOR₆Carboxylic acid ester represented by
Group; -CONR₇R₈A carbamoyl group represented by the formula:
_TwoNR₉R_TenA sulfamoyl group represented by the formula:_ThreeR_{1 1}
And the like. Concrete
Typically, D₁~ D₄₂The same ones as illustrated in the description
I can do it.

The above-mentioned straight-chain, branched-chain, cyclic alkyl group, straight-chain, branched-chain, cyclic alkenyl group and aryl group may be further substituted, and the substituent may be a methoxy group or an ethoxy group. An alkoxy group having 1 to 10 carbon atoms such as n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group; methoxymethoxy group, ethoxymethoxy group, propoxymethoxy group, ethoxyethoxy group An alkoxyalkoxy group having 2 to 12 carbon atoms such as a propoxyethoxy group, a methoxybutoxy group, and the like;
C3 such as methoxymethoxymethoxy, methoxymethoxyethoxy, methoxyethoxymethoxy, methoxymethoxyethoxy, ethoxyethoxymethoxy
Aryloxy group; aryl group having 6 to 12 carbon atoms such as phenyl group, tolyl group, xylyl group (these may be further substituted with a substituent); phenoxy group, tolyloxy group ,
6-1 carbon atoms such as xylyloxy group and naphthyloxy group
2, an alkenyloxy group having 2 to 12 carbon atoms such as an allyloxy group and a vinyloxy group; a cyano group; a nitro group; a hydroxyl group; a tetrahydrofuryl group; an amino group; an N, N-dimethylamino group; An alkylamino group having 1 to 10 carbon atoms such as a diethylamino group; and a carbon atom having 1 to 6 carbon atoms such as a methylsulfonylamino group, an ethylsulfonylamino group, and an n-propylsulfonylamino group.
An alkylsulfonylamino group; a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom; a methoxycarbonyl group;
An alkoxycarbonyl group having 2 to 7 carbon atoms such as an ethoxycarbonyl group, an n-propoxycarbonyl group, an isopropoxycarbonyl group, and an n-butoxycarbonyl; a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, and isopropylcarbonyl An oxy group, an alkylcarbonyloxy group having 2 to 7 carbon atoms such as an n-butylcarbonyloxy group; a methoxycarbonyloxy group, an ethoxycarbonyloxy group, an n-propoxycarbonyloxy group, an isopropoxycarbonyloxy group, an n-
It may be substituted with an alkoxycarbonyloxy group having 2 to 7 carbon atoms such as a butoxycarbonyloxy group. Further, a cyclic alkyl group having 3 to 12 carbon atoms, 2 to 12 carbon atoms
Examples of the substituent of the linear or branched alkenyl group include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, and n-heptyl groups. Examples thereof include a linear or branched alkyl group of 1 to 12 and the like.

R _{1 to} R ₁₁ each represent a hydrogen atom, a linear or branched alkyl group which may be substituted, a cyclic alkyl group which may be substituted, an alkenyl group which may be substituted, a cyclic alkenyl which may be substituted; And a phenyl group which may be substituted (the substituents include those described above).

Preferred as Y are an unsubstituted or halogenated alkyl group, an unsubstituted or halogenated alkylthio group, an unsubstituted or halogenated alkoxy group, and an unsubstituted or substituted C6-C18 group. Is an aryl group, a cyano group, a nitro group, a hydroxyl group, an alkoxycarbonyl group or a halogen atom. As the halogen which is a substituent of the alkyl group, the alkylthio group and the alkoxy group, a fluorine atom is particularly preferable.

Preferred examples of the compound represented by the general formula (1) or (1) 'include, for example, the following Tables 1 to 6
The present invention is not limited to these compounds.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

[0024]

[Table 5]

[0025]

[Table 6]

In the present specification, "t-Bu" represents a tertiary butyl group, and "i-Pr" represents an isopropyl group. As the metal that forms a chelate with the compound of the general formula (1) or (1) ′, various metals capable of forming a complex can be used, but Ni, Co, and Cu are preferable because of their good absorption spectrum shape. , Fe, Zn, Pd and the like are preferable.

The method for producing the metal chelate dye of the present invention is not particularly limited, and it can be synthesized using a reaction known per se. For example, the compound represented by the general formula (1) can be produced by the following route.

[0028]

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(Wherein A, X and Y have the same meanings as in the above formula (1)) First, the heterocyclic amine (a) is diazotized according to a conventional method. The obtained diazotized product is coupled with the isoxazole derivative (b) according to a conventional method. The obtained compound of the general formula (1) is dissolved in a solvent, a compound of the above-mentioned transition metal that is soluble in the same solvent is added, and the mixture is stirred to obtain the metal chelate dye of the present invention. The compound of the general formula (1) ′ can be produced in the same manner.

The metal chelate dye of the present invention is useful as a dye for use in a recording layer of an optical recording medium, for example, because it has excellent thin film forming properties when forming a film from a solution containing the dye. Further, the metal chelate dye of the present invention has a recording layer coating film containing the dye having a shorter wavelength (350 nm to 5 nm).
In the (00 nm) region, it has an absorption of an intensity suitable for recording and reproduction by a laser beam, and is extremely useful as a dye used in a recording layer of an optical recording medium for recording and reproduction corresponding to a short wavelength laser. The optical recording medium of the present invention is basically composed of a substrate and a recording layer containing the metal chelate dye, and further includes an undercoat layer, a metal reflective layer, and a protective layer on the substrate if necessary. May be provided. An example of a preferable layer configuration includes a medium having a high reflectance in which a metal reflective layer such as gold, silver, and aluminum and a protective layer are provided on the recording layer.

Hereinafter, the optical recording medium of the present invention will be described by taking a medium having this structure as an example. The material of the substrate in the optical recording medium of the present invention may be basically any material as long as it is transparent at the wavelength of the recording light and the reproducing light. As such a material, for example, acrylic resin, methacrylic resin, polycarbonate resin, vinyl chloride resin, vinyl acetate resin, polyester resin, polyethylene resin, polypropylene resin, polyimide resin, polystyrene resin, synthetic resin such as epoxy resin, glass, Examples thereof include those in which a coating layer made of a radiation-curable resin such as a photocurable resin is provided on glass, and the like, and injection-molded polycarbonate resins are particularly preferable in terms of high productivity, cost, and moisture absorption resistance. Amorphous polyolefin is preferred from the viewpoint of chemical resistance, moisture absorption resistance, and the like. Further, a glass substrate is preferable in terms of high-speed response and the like.

These substrate materials are formed into a disk-shaped substrate by an injection molding method 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. When the guide groove is spiral, the groove pitch is preferably about 0.5 to 1.2 μm.

The recording layer containing the chelate dye of the present invention is formed on the substrate or, if necessary, on the undercoat layer. Examples of the method for forming the recording layer include thin film forming methods generally used such as a vacuum evaporation method, a sputtering method, a doctor blade method, a casting method, a spin coating method, and an immersion method. The coating method is particularly preferred. In the case of film formation by the spin coating method, the number of rotation is preferably 500 to 5000 rpm, and after spin coating, a treatment such as heating or exposure to a solvent vapor may be performed in some cases.

When forming the recording layer by a coating method such as a doctor blade method, a casting method, a spin coating method, and a dipping method, the coating solvent is not particularly limited as long as it is a solvent which does not attack the substrate. For example, ketone alcohol solvents such as diacetone alcohol and 3-hydroxy-3-methyl-2-butanone; cellosolve solvents such as methyl cellosolve and ethyl cellosolve; chain hydrocarbon solvents such as n-hexane and n-octane ; Cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane,
Cyclic hydrocarbon solvents such as n-butylcyclohexane, tert-butylcyclohexane, and cyclooctane; Perfluoroalkyl alcohol solvents such as tetrafluoropropanol, octafluoropentanol, and hexafluorobutanol; methyl lactate, ethyl lactate, and methyl isobutyrate And the like.

The recording layer is formed of a transition metal chelate compound (eg, acetylacetonate chelate, bisphenyldithiol, salicylaldehyde oxime, bisdithio-α) as a singlet oxygen quencher in order to improve the stability and light resistance of the recording layer. -Diketone, etc.) or a recording sensitivity improver such as a metal compound for improving the recording sensitivity. Here, the metal-based compound refers to a compound contained in the compound in the form of a metal atom such as a transition metal, an ion, a cluster, or the like. Organometallic compounds such as azobenzene-based complexes, dioxime-based complexes, nitrosoaminophenol-based complexes, pyridyltriazine-based complexes, acetylacetonate-based complexes, metallocene-based complexes, and porphyrin-based complexes are exemplified. The metal atom is not particularly limited, but is preferably a transition metal.

Further, if necessary, other types of dyes may be used in combination. Other types of dyes mainly absorb in the laser wavelength range for recording, and absorb heat of the irradiated laser light to cause heat, such as decomposition, evaporation, and dissolution, on the recording layer, reflective layer, or substrate at that location. There is no particular limitation as long as pits are formed with a substantial deformation. Also,
Using a dye suitable for recording with a near-infrared laser with a wavelength selected from 770 to 830 nm such as CD-R and a red laser with a wavelength of 620 to 690 nm such as DVD-R, Thus, an optical recording medium corresponding to laser recording can be used.

Other dyes include metal-containing azo dyes,
Phthalocyanine dye, naphthalocyanine dye, cyanine dye, azo dye, squarylium dye, metal-containing indoaniline dye, triarylmethane dye,
Examples include merocyanine dyes, azulenium dyes, naphthoquinone dyes, anthraquinone dyes, indophenol dyes, xanthene dyes, oxazine dyes, and pyrylium dyes.

Further, if necessary, a binder, a leveling agent, an antifoaming agent and the like can be used in combination. Preferred binders include polyvinyl alcohol, polyvinyl pyrrolidone, nitrocellulose, cellulose acetate, ketone resin, acrylic resin, polystyrene resin, urethane resin, polyvinyl butyral, polycarbonate, polyolefin and the like. The thickness of the recording layer is
It may vary depending on the recording method and is not particularly limited, but is preferably 50 to 300 nm.

A reflective layer may be formed on the recording layer, and its thickness is preferably from 50 to 300 nm. As a material of the reflection layer, a material having a sufficiently high reflectance at the wavelength of the reproduction light, for example, Au, Al, Ag, Cu, Ti, Cr, Ni, Pt, Ta, Cr
And Pd can be used alone or in the form of an alloy. Among them, Au, Al, and Ag have high reflectivity and are suitable as the material of the reflective layer. In addition to these as main components, the following may be included. For example, Mg, Se, Hf,
V, Nb, Ru, W, Mn, Re, Fe, Co, Rh, Ir, Cu, Zn, C
Metals and metalloids such as d, Ga, In, Si, Ge, Te, Pb, Po, Sn, and Bi can be mentioned. Among them, those containing Ag as a main component are particularly preferable because they are inexpensive, easily reflect a high reflectance, and when a print receiving layer described later is provided, a white and beautiful ground color can be obtained. Here, the main component means one 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. Examples of a method for forming the reflective layer 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 for improving reflectance, improving recording characteristics, improving adhesion, etc. on the substrate or below the reflective layer,
An adhesive layer can also be provided.

The material of the protective layer formed on the reflective layer is not particularly limited as long as it protects the reflective layer from external force. Examples of the organic material include a thermoplastic resin, a thermosetting resin, an electron beam curable resin, and a UV curable resin. Further, as inorganic substances, SiO ₂ , Si
N ₄ , MgF ₂ , SnO _{2 and the} like can be mentioned.

The thermoplastic resin, thermosetting resin and the like can be formed by dissolving in an appropriate solvent, applying a coating solution, and 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. As UV curable resin,
For example, acrylate resins such as urethane acrylate, 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 instead of 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 0.1 to 1
Although it is in the range of 00 μm, it is preferably 3 to 30 μm in the present invention.

Further, a substrate may be further bonded to the reflective layer surface, or two optical recording media may be bonded to each other 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. It is to be noted that a print receiving layer which can be written (recorded) by various printing means such as ink jet, thermal transfer, or a writing instrument may be formed on a surface other than the recording / reproducing light incident surface.

The laser beam used for the optical recording medium of the present invention is preferably shorter in wavelength for high-density recording, but is more preferably 350 to 530 nm. Representative examples of such laser light include laser light having center wavelengths of 410 nm and 515 nm. An example of laser light having a wavelength in the range of 350 to 530 nm can be obtained by using a high-power semiconductor laser of 410 nm blue or 515 nm turquoise.Others, for example, (a) a fundamental oscillation wavelength of 740 to 740 nm 960n
m, a semiconductor laser capable of continuous oscillation, or (b) excited by a semiconductor laser, and having a fundamental oscillation wavelength of 740 to 960.
It can also be obtained by converting the wavelength of any of solid-state lasers capable of continuous oscillation of nm using a second harmonic generation element (SHG).

The SHG may be any piezo element that does not have inversion symmetry.
ADP, BNN, KN, LBO, compound semiconductor, and the like are preferable. As a specific example of the second harmonic, the fundamental oscillation wavelength is
In the case of a semiconductor laser of 860 nm, its harmonic is 430 nm, and in the case of a solid-state laser pumped by a semiconductor laser, it is 4 which is the harmonic of a Cr-doped LiSrAlF ₆ crystal (having a fundamental oscillation wavelength of 860 nm).
30 nm and the like.

The recording on the optical recording medium of the present invention obtained as described above is performed by irradiating the recording layer provided on both sides or one side of the substrate with a laser beam focused to about 0.4 to 0.6 μm. In the portion irradiated with the laser beam, thermal deformation of the recording layer such as decomposition, heat generation, and melting occurs due to absorption of the laser beam energy, and the optical characteristics change.
Reproduction of recorded information is performed by reading the difference in reflectance between a portion where thermal deformation (change in optical characteristics) has occurred and a portion where thermal deformation (change in optical characteristics) has not occurred.

[0048]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention. Example 1 (a) Production of dye

[0049]

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The 3-amino-5- (t) represented by the above structural formula [I]
(ert-butyl) -isoxazole 1.41 g (0.01 mol)
l) was dissolved in 10 ml of acetic acid and 9 g of phosphoric acid.
The mixture was stirred at a temperature of 3.5 ° C., and 3.52 g of 43% nitrosylsulfuric acid was added dropwise and stirred for 1 hour to perform diazotization. The obtained diazotization reaction solution was subjected to the following structural formula [II]

[0051]

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A solution obtained by dissolving 1.77 g (0.011 mol) of 3-phenyl-5-isoxazolone, 0.4 g of urea, and 3.7 g of sodium acetate in 40 ml of methanol + 10 ml of water was added at 0 to 5 ° C. It was dripped while adjusting to ５5. After the addition, the mixture was further stirred for 3 hours.
The reaction was filtered and the filtrate was washed with water and dried. This crude product was subjected to chromatography using silica gel packed in a φ35 mm × 450 mm column with a developing solvent (ethyl acetate) to isolate the intended product, and the following structural formula [I
II] 1.53 g (49% yield) was obtained.

[0053]

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0.4 g of the compound of the formula [III] is dissolved in 25 ml of tetrahydrofuran, and 0.19 g of nickel acetate tetrahydrate in methanol at room temperature under stirring.
5 ml solution was added dropwise. After the dropwise addition, the mixture was stirred for 2 hours and filtered to remove insolubles. Thereafter, 45 ml of demineralized water was added to the filtrate to precipitate a precipitate. After stirring for 2 hours, the product was collected by filtration. The product is washed with water, dried and
Metal chelate dye represented by the following structural formula [IV]
35 g (80% yield) were obtained. Mass spectrum of this compound m / z = 313, λmax in chloroform = 396n
m, molar extinction coefficient was 3.2 × 10 ⁴ .

[0055]

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(B) Evaluation The dye represented by the structural formula [IV] was dissolved in octafluoropentanol and adjusted to 1.0 wt%. A solution obtained by filtering the solution was dropped on an injection-molded polycarbonate resin substrate having a diameter of 120 mm and a thickness of 1.2 mm, applied by a spinner method, and then dried at 100 ° C. for 30 minutes. The maximum absorption wavelength (λmax) of this coating film was 403 nm.

On this coating film, a silver film is formed by a sputtering method or the like to form a reflective layer, and then a UV curable resin is applied by spin coating or the like and cured by UV irradiation to form a protective layer. Then, it can be used as an optical recording medium. This optical recording medium is considered to be capable of recording / reproducing with a semiconductor laser having a center wavelength of 410 nm, for example, based on the value of λmax of the coating film.

[0058]

The solution of the metal chelate dye of the present invention can form a coating film having an absorption suitable for recording / reproducing by short-wavelength laser light and has excellent film-forming properties. A recording medium having a recording layer using a metal chelate dye is useful as an optical recording medium for recording and reproduction corresponding to a short wavelength laser.

Claims (6)

[Claims] 1. A metal chelate dye comprising a compound represented by the following general formula (1) or (1) ′ and a metal. Embedded image (In the formulas (1) and (1) ′, A and A ′ represent a heteroaromatic ring residue containing a carbon atom and a nitrogen atom to which they are bonded, X represents a group having an active hydrogen atom, Y represents a hydrogen atom or an arbitrary substituent.) 2. In the general formulas (1) and (1) ′, A and A ′
Is an oxazole ring, a pyrazole ring, an imidazole ring,
The metal chelate dye according to claim 1, which represents an isoxazole ring, a thiadiazole ring or a triazole ring residue. 3. In the general formulas (1) and (1) ′, A and A ′ are isoxazole ring residues.
The metal chelate dye as described above. 4. The metal chelate dye according to claim 1, wherein the metal is selected from the group consisting of Ni, Co, Cu, Fe, Zn and Pd. 5. An optical recording medium provided with a recording layer capable of recording and / or reproducing information by a laser on a substrate, wherein the recording layer comprises the metal chelate dye according to claim 1. An optical recording medium characterized by containing. 6. The laser wavelength for recording or reproducing information is 35.
The optical recording medium according to claim 5, wherein the optical recording medium has a thickness of 0 nm to 530 nm.