JP2000263942A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the light-resistance and the preservation stability, and at the same time, make adaptable to a high density disk system of the next generation by containing at least one kind of azo metal chelate compounds comprising an azo compound represented by a specified structural formula, and a metal or its salt, in a recording layer. SOLUTION: At least one kind of a metal chelate compound comprising an azo compound represented by a specified formula (in the formula, R1 and R2 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group or aryl group, and R1 and R2 may form a cycle by linking. R3-R11 each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxy group, a carboxy group, an amino group, or a calbamoyl group, and R3 and R4, R4 and R1 or R2, R5 and R1 or R2, R6 and R7, R7 and R8, R8 and R9, R9 and R10, and R10 and R11 may form a cycle by linking. X represents a hydroxy group, an alkyloxy group, an aryloxy group, or a carboxy group.) a metal or its salt, is contained in a recording layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium, and more particularly, to irradiating a light beam to cause an optical change in a transmittance and a reflectance of a recording material, thereby recording and reproducing information. Optical recording medium capable of performing additional recording
In particular, the present invention relates to a large-capacity data write-once optical disc (large-capacity write-once compact disc, DVD-R).

[0002]

2. Description of the Related Art At present, as a next-generation large-capacity optical disk, D
The development of VD-R (large capacity write-once compact disc) is underway. The elemental technologies for improving the recording capacity require the development of technologies such as the development of recording materials for miniaturizing recording pits, the adoption of image compression technology represented by MPEG2, and the shortening of the wavelength of semiconductor lasers for reading recording pits. is there. Until now, only 670 nm AlGaInP laser diodes have been commercialized as bar code readers and measuring instruments as semiconductor lasers in the red wavelength range. It is being used in the optical storage market. In the case of a DVD drive, the light source is standardized at two wavelengths, a 635 nm band and a 650 nm band laser diode. On the other hand, a read-only DVD-ROM drive is commercialized at a wavelength of about 650 nm.

[0003] Under these circumstances, the most preferable DVD-
The R media is a medium that can record and reproduce at a wavelength of about 650 nm or less. As for DVD-R, for example, a recording material comprising an imidazole-based azomethine dye and a metal reflection layer (Japanese Patent Application Laid-Open Nos. 8-198872 and 8-20901).
No. 2, No. 8-283263) and cyanine dyes /
Using a metal reflection layer as a recording material (PIONEE)
R R & D vol. 6 No. 2: DVD-Reco
Development of rdables, basic development of DVD-R dye disks), etc., but recording materials that are excellent in light resistance and storage stability and can be recorded and reproduced by an optical pickup using a laser of 650 nm or less are still available. It has not been developed yet.

The current CD-R disk system has a configuration in which the laser used has an oscillation wavelength of 770 to 790 nm and can perform recording and reproduction. CD-R is 6 in the recording layer.
Using a dye having a maximum absorption wavelength at 80 to 750 nm,
Because of its optical constant and film thickness configuration, it is set to obtain a high reflectance at 770 to 790 nm.
In the wavelength range of m or less, the reflectivity is extremely low, and it is impossible to cope with the emission of the laser wavelength, and information recorded and reproduced by the current CD-R system cannot be reproduced by the DVD-R disk system.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above situation, and has a DVD-R using a semiconductor laser having an oscillation wavelength shorter than that of the conventional system. The present invention provides a recording material for an optical recording medium having excellent light resistance and storage stability applicable to a disc system, and a CD-R which enables information recorded on a CD-R disc system to be reproduced on a DVD-R disc system. It is an object to provide a recording material for an R medium.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a recording layer containing a dye having a specific structure as a main component is provided so that a next-generation semiconductor laser having an oscillation wavelength of 700 nm or less can be used. It has been found that the compound of the present invention can be applied to a large-capacity optical disk system, and the compound of the present invention is mixed with an organic dye used as a current recording material for CD-R, so that the compound can be used even in a wavelength region of 700 nm or less. The inventors have found that it is possible to obtain the reflectance, and have completed the present invention.

That is, according to the present invention, first, in an optical recording medium having a recording layer provided on a substrate, an azo compound represented by the following general formula (I) and a metal or a salt thereof are contained in the recording layer. An optical recording medium comprising at least one azo metal chelate compound comprising:

Embedded image (Wherein, R ₁ and R ₂ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and R ₁ and R ₂ are linked to form a ring. R _{3 to} R ₁₁ each independently represent a hydrogen atom,
Halogen atom, nitro group, cyano group, hydroxyl group, carboxy group, amino group, carbamoyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted heterocyclic residue, substituted or unsubstituted Alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkyloxycarbonyl group, substituted or unsubstituted aryloxycarbonyl Group, a substituted or unsubstituted alkylcarbonylamino group, a substituted or unsubstituted arylcarbonylamino group, a substituted or unsubstituted alkylcarbamoyl group, a substituted or unsubstituted arylcarbamoyl group, or a substituted or unsubstituted alkenyl group , R ₃ and R _{4, 4} and R ₁ or R _2, R ₅ and R ₁ or R _2, R ₆ and R _7, R ₇ and R _8, R ₈ and R _9, R ₉ and R _10, R
₁₀ and R ₁₁ may be linked to form a ring. X is a hydroxy group, an alkyloxy group, an aryloxy group, a carboxy group, an alkyloxycarbonyl group, an aryloxycarbonyl group, an amino group, an alkylcarbonylamino group, an arylcarbonylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, Represents a carbamoyl group, an alkylcarbamoyl group, an arylcarbamoyl group, a sulfo group, a sulfino group, a sulfeno group, an aminosulfonyl group, an alkylsulfonyl group, or an arylsulfonyl group. (2) The optical recording medium according to the above (1), wherein the metal atom of the azo metal chelate compound is at least one of aluminum, chromium, manganese, cobalt, nickel, copper and zinc. Is done. Third, in the optical recording medium according to the first or second aspect, the recording layer is formed of the azo metal chelate compound and 6
An optical recording medium comprising a mixed layer with a dye having a maximum absorption wavelength at 80 to 750 nm is provided.
Fourth, in the optical recording medium described in the third above, 68
An optical recording medium is provided, wherein the dye having a maximum absorption wavelength at 0 to 750 nm is at least one of a cyanine dye, a phthalocyanine dye, and an azo metal chelate compound. Fifth, in the optical recording medium according to any one of the first to fourth aspects, the refractive index n of the recording layer single layer with respect to light in a wavelength range of recording / reproducing wavelength ± 5 nm is 1.5 ≦ n ≦
3.0, and an extinction coefficient k is 0.02 ≦ k ≦ 0.2. Sixth,
The optical recording medium according to any one of the first to fourth aspects, wherein the slope of the weight loss with respect to the temperature in the main weight loss process is 2% / ° C. or more in thermogravimetric analysis of the organic dye. A medium is provided. Seventh, in the optical recording medium according to any one of the first to fourth, the thermogravimetric analysis of the organic dye shows that the total weight loss in the main weight loss process is 30% or more;
Further, an optical recording medium characterized by having a weight loss start temperature of 350 ° C. or lower is provided. Eighth, in the optical recording medium according to any one of the first to seventh aspects, the track pitch on the substrate is 0.7 to 0.8 μm, the groove width is a half width, and 0.20 to 0. An optical recording medium having a thickness of 36 μm is provided.

In the optical recording medium of the present invention, the recording layer contains at least one of the azo compound represented by the general formula (I) and a metal chelate compound composed of a metal or a salt thereof. It is excellent in light resistance and storage stability applicable to a DVD-R disk system using a semiconductor laser of 700 nm or less, and in another aspect, the recording layer is composed of one of the metal chelate compounds described above with 680 to 680.
Since it is composed of a mixed layer with a dye having a maximum absorption wavelength at 750 nm, a high reflectivity can be obtained even in a wavelength region of 700 nm or less, and information recorded by a CD-R disk system can be used as a DVD-R. The data can be reproduced by the R disk system.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the optical recording medium of the present invention, the recording layer has the following general formula (I)
And at least one metal chelate compound comprising a metal or a salt thereof.

Embedded image (Wherein, R ₁ and R ₂ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and R ₁ and R ₂ are linked to form a ring. R _{3 to} R ₁₁ each independently represent a hydrogen atom,
Halogen atom, nitro group, cyano group, hydroxyl group, carboxy group, amino group, carbamoyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted heterocyclic residue, substituted or unsubstituted Alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkyloxycarbonyl group, substituted or unsubstituted aryloxycarbonyl Group, a substituted or unsubstituted alkylcarbonylamino group, a substituted or unsubstituted arylcarbonylamino group, a substituted or unsubstituted alkylcarbamoyl group, a substituted or unsubstituted arylcarbamoyl group, or a substituted or unsubstituted alkenyl group , R ₃ and R _{4, 4} and R ₁ or R _2, R ₅ and R ₁ or R _2, R ₆ and R _7, R ₇ and R _8, R ₈ and R _9, R ₉ and R _10, R
₁₀ and R ₁₁ may be linked to form a ring. X is a hydroxy group, an alkyloxy group, an aryloxy group, a carboxy group, an alkyloxycarbonyl group, an aryloxycarbonyl group, an amino group, an alkylcarbonylamino group, an arylcarbonylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, Represents a carbamoyl group, an alkylcarbamoyl group, an arylcarbamoyl group, a sulfo group, a sulfino group, a sulfeno group, an aminosulfonyl group, an alkylsulfonyl group, or an arylsulfonyl group. )

Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, and an n-octyl group. Primary alkyl groups such as nonyl group and n-decyl group; isobutyl group, isoamyl group, 2-methylbutyl group, 2-methylpentyl group, 3-methylpentyl group, 4
-Methylpentyl group, 2-ethylbutyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 2-ethylpentyl group,
3-ethylpentyl group, 2-methylheptyl group, 3-methylheptyl group, 4-methylheptyl group, 5-methylheptyl group, 2-ethylhexyl group, 3-ethylhexyl group, isopropyl group, sec-butyl group, 1- Ethylpropyl group, 1-methylbutyl group, 1,2-dimethylpropyl group, 1-methylheptyl group, 1-ethylbutyl group,
1,3-dimethylbutyl group, 1,2-dimethylbutyl group, 1-ethyl-2-methylpropyl group, 1-methylhexyl group, 1-ethylheptyl group, 1-propylbutyl group, 1-isopropyl-2- Methylpropyl group, 1-ethyl-2-methylpropyl group, 1-ethyl-2-methylbutyl group, 1-propyl-2-methylpropyl group, 1-
Methylheptyl group, 1-ethylhexyl group, 1-propylpentyl group, 1-isopropylpentyl group, 1-isopropyl-2-methylbutyl group, 1-isopropyl-3
Secondary alkyl groups such as -methylbutyl group, 1-methyloctyl group, 1-ethylheptyl group, 1-propylhexyl group, 1-isobutyl-3-methylbutyl group; neopentyl group, tert-butyl group, tert-hexyl group, t
tertiary alkyl groups such as ert-amyl group and tert-octyl group; cyclohexyl group, 4-methylcyclohexyl group, 4-ethylcyclohexyl group, 4-tert-butylcyclohexyl group, 4- (2-ethylhexyl) cyclohexyl group, and bornyl And cycloalkyl groups such as an isobornyl group (adamantane group).

Further, these primary and secondary alkyl groups are
A hydroxyl group, a halogen atom, a nitro group, a carboxy group, a cyano group, a substituted or unsubstituted aryl group, may be substituted with a substituted or unsubstituted heterocyclic residue, etc.
The alkyl group may be substituted via an atom such as sulfur or nitrogen. Examples of the alkyl group substituted via oxygen include a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group, a butoxyethyl group, an ethoxyethoxyethyl group, a phenoxyethyl group,
Methoxypropyl group, ethoxypropyl group, piperidino group, morpholino group, etc., as the alkyl group substituted through sulfur, methylthioethyl group, ethylthioethyl group, ethylthiopropyl group, phenylthioethyl group, etc. Examples of the alkyl group substituted via nitrogen include a dimethylaminoethyl group, a diethylaminoethyl group, and a diethylaminopropyl group.

Specific examples of the above aryl group include phenyl, pentalenyl, indenyl, naphthyl, azulenyl, heptalenyl, biphenylenyl, as
-Indacenyl group, s-indacenyl group, acenaphthalenyl group, fluorenyl group, phenalenyl group, phenanthranyl group, anthranyl group, fluoracenyl group, acephenanthrenyl group, aceanthrylene group, triphenylenyl group, pyrenyl group, chrysenyl group, naphthacenyl group And the like. Further, these aryl groups include a hydroxyl group,
It may be substituted with a halogen atom, a nitro group, a carboxy group, a cyano group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic residue, and the like, and via an atom such as oxygen, sulfur, or nitrogen. The alkyl group may be substituted.

Specific examples of the above heterocyclic residue include furyl, thienyl, pyrrolyl, 2H-pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl, furazanyl, pyranyl and the like. Group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, pyrrolinyl group, pyrrolidinyl group, imidazolinyl group, pyrazolinyl group, pyrazolidinyl group, piperidyl group, pyrrelidino group, piperazinyl group, morpholinyl group, morpholino group, indolyl group, isoindolyl group, 1H-indazolyl group, 4H-chromenyl group, quinolyl group, isoquinolyl group, cinnolinyl group, quinazolinyl group, quinoxalinyl group, phthalazinyl group, prenyl group, pteridinyl group, xanthenyl group, carbazolyl group, Ntorijiniru group, acridinyl group, phenazinyl group, phenanthrolinyl group, indolinyl group, isoindolinyl group, etc. chromanyl group. Further, these heterocyclic residues may be substituted with a hydroxyl group, a halogen atom, a nitro group, a carboxy group, a cyano group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic residue, and the like. It may be substituted with the above-mentioned alkyl group via an atom such as oxygen, sulfur, or nitrogen. Further, these substituents may be such that a plurality of the same or different substituents are substituted on the ring.

Specific examples of the halogen atom include fluorine, chlorine, bromine and iodine.

Specific examples of the above alkyloxy group include:
It suffices that the substituted or unsubstituted alkyl group is directly bonded to the oxygen atom, and specific examples of the alkyl group include the specific examples described above. Further, specific examples of the above aryloxy group may be those in which a substituted or unsubstituted aryl group is directly bonded to an oxygen atom, and specific examples of the aryl group include the above specific examples. .

Specific examples of the above alkylamino group include:
What is necessary is just that a substituted or unsubstituted alkyl group is directly bonded to the nitrogen atom, and specific examples of the alkyl group include the aforementioned specific examples. Further, alkyl groups may be bonded to each other to form a ring such as a piperidino group, a morpholino group, a pyrrolidyl group, a piperazinyl group, an indolenyl group, an isoindrenyl group, and the like. Further, specific examples of the above arylamino group may be those in which a substituted or unsubstituted aryl group is directly bonded to a nitrogen atom, and specific examples of the aryl group include the above specific examples. .

Specific examples of the above alkyloxycarbonyl group may be those in which a substituted or unsubstituted alkyl group is directly bonded to an oxygen atom, and specific examples of the alkyl group include the aforementioned specific examples. Can be. Also,
Specific examples of the above aryloxycarbonyl group may be those in which a substituted or unsubstituted aryl group is directly bonded to an oxygen atom, and specific examples of the aryl group include the aforementioned specific examples.

Specific examples of the above-mentioned alkylcarbonylamino group are those in which a substituted or unsubstituted alkyl group is directly bonded to a carbon atom, and specific examples of the alkyl group include the aforementioned specific examples. Can be. Also,
Specific examples of the above arylcarbonylamino group may be those in which a substituted or unsubstituted aryl group is directly bonded to a carbon atom, and specific examples of the aryl group include the aforementioned specific examples.

Specific examples of the above-mentioned alkylcarbamoyl group include those in which a substituted or unsubstituted alkyl group is directly bonded to a nitrogen atom. Specific examples of the alkyl group include the aforementioned specific examples. it can. Further, alkyl groups may be bonded to each other to form a ring such as a piperidino group, a morpholino group, a pyrrolidyl group, a piperazinyl group, an indolenyl group, an isoindrenyl group, and the like. Further, specific examples of the arylcarbamoyl group include those in which a substituted or unsubstituted aryl group is directly bonded to a nitrogen atom, and specific examples of the aryl group include the specific examples described above. .

Specific examples of the amino group in which R ₁ and R ₂ are linked to form a ring include a piperidino group, a morpholino group, a pyrrolidyl group, a piperazyl group, an imidazolidyl group, a pyrazolidyl group, an indolinyl group, an isoindolinyl group, a pyrrolyl group, Examples include an indolyl group, an isoindolyl group, and a carbazolyl group.

Specific examples of the metal atom include aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, zirconium, niobium, molybdenum, technenium, ruthenium, rhodium, palladium and the like. The azo metal chelate compounds of aluminum, chromium, manganese, iron, cobalt, nickel, copper and zinc have excellent optical properties as optical recording materials.

Specific examples of the azo metal chelate compound used in the present invention include those shown in Tables 1 to 3.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

Further, as described above, the recording layer mainly comprises a mixture of at least one of the azo metal chelate compounds and an organic dye having a maximum absorption wavelength at 680 to 750 nm. This is a CD-R recording medium that can be recorded and reproduced by the system and can be reproduced only in the next-generation system. In this case, as the dye having the maximum absorption wavelength at 680 to 750 nm, the dyes described in the publications described in the prior art can be used. Particularly, a cyanine dye, a phthalocyanine dye and an azo metal chelate compound are preferable.

Preferred examples of the cyanine dye include those represented by the following general formula (II).

Embedded image In the formula, R ^{21 to} R ²⁴ are an alkyl group having 1 to 3 carbon atoms, R ²⁵ ,
R ²⁶ is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms;
₁ represents an acid anion. Note that the aromatic ring may be condensed with another aromatic ring, or may be substituted with an alkyl group, a halogen atom, an alkoxy group, or an acyl group.

Preferred examples of the phthalocyanine dye include those represented by the following general formula (III) or (IV).

Embedded image In the formula, M ¹ is Ni, Pd, Cu, Zn, Co, Mn, F
e, TiO or VO. X ^{11 to} X ¹⁴ are each independently -OR, -SR or a hydrogen atom at the α-position of the substitution position, and not all of them are hydrogen atoms. R represents a substituted or unsubstituted linear or branched alkyl group having 3 to 12 carbon atoms, a cycloalkyl group, or a substituted or unsubstituted aryl group. Substituents on the benzene ring other than X ^{11 to} X ¹⁴ are a hydrogen atom or a halogen atom.

[0029]

Embedded imageWhere M^TwoRepresents Si, Ge, In, or Sn. X
¹⁵~ X¹⁸Are each independently -OR at the substitution position α-, -S
R or a hydrogen atom, and all of them are hydrogen atoms
Absent. R represents a substituted or unsubstituted C 3-12 carbon atom.
Linear or branched alkyl, cycloalkyl or
Represents a substituted or unsubstituted aryl group. Y¹, Y^TwoIs
-OSiR¹⁷R¹⁸R¹⁹, -OCOR¹⁷R¹⁸R¹⁹, Or-
OPOR ¹⁷R¹⁸R¹⁹And R¹⁷~ R¹⁹Is German
Stands for an alkyl group or an aryl group having 1 to 10 carbon atoms.
You. X¹⁵~ X¹⁸Other substituents on the benzene ring are hydrogen atoms
Or a halogen atom.

Preferred examples of the azo metal chelate compound include one or more azo metal chelate compounds of an azo compound represented by the following general formula (V) and a metal. Preferred examples of the metal Are Ni, Mn,
Pd, Co, Cu, Zn and the like can be mentioned.

Embedded image In the formula, A represents a residue which forms a heterocyclic ring together with the carbon atom and the nitrogen atom to which it is bonded, and B represents an aromatic ring together with the two carbon atoms to which it is bonded. Or X represents a residue forming a heterocyclic ring, and X ₂ represents a group having an active hydrogen.

When at least one dye of the azo metal chelate compound of the present invention is used in combination with at least one dye represented by formulas (II) to (V), the weight composition ratio of the dye of the present invention is / [Dye of (II) to (V)] = 10 /
100-90 / 100, preferably 40 / 100-20
/ 100. When both dyes are used in combination, the thickness of the recording layer is 500 to 5 μm, preferably 1000 to 5 μm.
000.

Next, the configuration of the recording medium of the present invention will be described. FIG. 1 is a diagram showing an example of a layer configuration applicable to the recording medium of the present invention, which is an example of a write-once optical disc. The recording layer 2 is provided on the substrate 1 via an undercoat layer 3 if necessary.
And, if necessary, a protective layer 4. Further, a hard coat layer 5 can be provided below the substrate 1 as needed. FIG. 2 is a diagram showing another example of a layer structure applicable to the recording medium of the present invention, which is an example of a CD-R medium. A reflective layer 6 is provided on the recording layer 2 having the configuration shown in FIG. FIG. 3 is a diagram showing an example of a layer structure of another type (for DVD-R) applicable to the recording medium of the present invention. In this case, an adhesive layer 8 and a protective layer 8 are formed on the protective layer 4 having the structure of FIG. A substrate 7 is provided. That is, the recording medium of the present invention has a recording layer (organic thin film layer) having the configuration shown in FIGS.
Can be made into an air sandwich structure sealed with another substrate through a space, or a laminated structure bonded through a protective layer.

That is, when the recording medium of the present invention is applied to a DVD-R, the configuration of the recording medium includes a first substrate and a second substrate (hereinafter, referred to as a first substrate and a second substrate). ) Are bonded together with an adhesive via a recording layer as a basic structure. The recording layer may be a single layer of an organic dye, or a laminate of an organic dye layer and a metal reflective layer to enhance the reflective layer. The recording layer and the substrate may be layered with an undercoat layer or a protective layer interposed therebetween, or may be formed by laminating them for improving the function. The most commonly used structure is a first substrate / organic dye layer / metal reflective layer / protective layer / adhesive layer / second substrate structure.

Next, the required characteristics of the constituent layers and the constituent materials thereof will be described. 1) Substrate As a necessary characteristic of the substrate, when recording / reproducing is performed from the substrate side, it must be transparent to the laser beam to be used. However, when recording / reproducing is performed from the recording layer side, it is not necessary to be transparent. Therefore, in the present invention, when two substrates are used in a sandwich shape, for example, if only the second substrate is transparent, the first substrate may be transparent or opaque. As the substrate material, for example, polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, plastic such as polyimide, glass, ceramic, metal or the like can be used. When only one substrate is used, or when two substrates are used in a sandwich form, a guide groove or a guide pit for tracking and a preformat such as an address signal are formed on the surface of the substrate or the first substrate. Must have been.

The substrate usually has a guide groove having a depth of 1000 to 2500 °. Track pitch is usually 0.7
.About.1.0 μm, but 0.7.about.
0.8 μm is preferred. Groove width is 0.18 ~ at half width
0.36 μm is preferred. If it is less than 0.18 μm, it may be difficult to obtain a sufficient tracking error signal intensity. On the other hand, if the thickness exceeds 0.36 μm, the recording portion tends to spread laterally when recording, which is not preferable.

2) Intermediate Layer Layers provided other than the substrate, the recording layer, the reflective layer, and the protective layer, including the undercoat layer and the like, are herein referred to as intermediate layers. This intermediate layer has improved adhesiveness, a barrier against water or gas, improved storage stability of the recording layer, improved reflectance, protection of the substrate from a solvent, guide grooves, guide pits,
It is used for the purpose of forming a preformat.
For the purpose of the polymer material, for example, ionomer resin, polyamide, vinyl resin, natural resin, natural polymer, silicone, various polymer compounds such as liquid rubber and silane coupling agent and the like can be used, For the purposes described above, other than the above-mentioned polymer materials, inorganic compounds such as SiO ₂ , MgF ₂ , SiO, TiO ₂ , Zn
O, TiN, SiN, etc., and further, a metal or a semi-metal,
For example, Zn, Cu, Ni, Cr, Ge, Se, Au, A
g, Al or the like can be used. For the purpose, a metal such as Al, Au, Ag or the like, or an organic thin film having a metallic luster such as a methine dye or a xanthene-based dye can be used. Cured resin, thermosetting resin, thermoplastic resin, or the like can be used. The thickness of the intermediate layer is 0.01 to 30
μm, preferably 0.05 to 10 μm is suitable.

3) Recording Layer The recording layer is capable of causing some optical change by irradiation with a laser beam and recording information by the change.
In this recording layer, at least one kind of the azo metal chelate compound of the present invention, and in some cases, furthermore, the compound represented by the general formula (II)
It is necessary that at least one of the dyes represented by (V) is contained. Further, these dyes can be used by mixing or laminating them with other organic dyes, metals, and metal compounds in order to improve optical characteristics, recording sensitivity, and signal characteristics. Other organic dyes in this case include polymethine dyes, naphthalocyanine-based, phthalocyanine-based, squarylium-based, croconium-based, pyrylium-based, naphthoquinone-based, anthraquinone (indanthrene) -based, xanthene-based, triphenylmethane-based, and azulene-based , A tetrahydrocholine-based, a phenanthrene-based, a triphenothiazine-based dye, and a metal complex compound. Examples of metals and metal compounds include In, Te, Bi,
Se, Sb, Ge, Sn, Al, Be, TeO ₂ , Sn
O, As, Cd and the like can be mentioned, and each of them can be used in the form of dispersion mixing or lamination. Further, various materials such as a polymer material, for example, an ionomer resin, a polyamide resin, a vinyl resin, a natural polymer, silicone, a liquid rubber, or a silane coupling agent may be dispersed and mixed in the dye, For the purpose of improvement, stabilizers (eg, transition metal complexes), dispersants, flame retardants, lubricants, antistatic agents, surfactants, plasticizers, and the like can be used together.

The recording layer is formed by vapor deposition, sputtering, C
It can be carried out by usual means such as VD or solvent application. When using the coating method, the above dye or the like is dissolved in an organic solvent, and spray, roller coating,
It can be performed by a conventional coating method such as dipping or spin coating. Examples of the organic solvent used include alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone, methyl ethyl ketone and cyclohexanone; amides such as N, N-dimethylacetamide and N, N-dimethylformamide; and sulfoxides such as dimethyl sulfoxide. , Tetrahydrofuran, dioxane, diethyl ether, ethers such as ethylene glycol monomethyl ether, esters such as methyl acetate, ethyl acetate, chloroform, methylene chloride, dichloroethane, carbon tetrachloride, aliphatic halogenated carbons such as trichloroethane,
Aromatics such as benzene, xylene, monochlorobenzene and dichlorobenzene, or methoxyethanol;
Cellsolves such as ethoxyethanol, and hydrocarbons such as hexane, pentane, cyclohexane, and methylcyclohexane. The thickness of the recording layer is 100
Å-10 μm, preferably 200Å-2000Å is suitable.

The refractive index n of the recording layer single layer with respect to light in the wavelength range of ± 5 nm for the recording / reproducing wavelength is preferably 1.5 ≦ n ≦ 3.0. If n is less than 1.5, it is difficult to obtain a sufficient optical change, and the recording modulation degree becomes low. On the other hand, if n exceeds 3.0, the wavelength dependency becomes too high and an error occurs even in the recording / reproducing wavelength range, which is not preferable. The extinction coefficient k is
0.02 ≦ k ≦ 0.2 is preferred. If k is less than 0.02, the recording sensitivity will be poor. If k exceeds 0.2, it is difficult to obtain a reflectance of 50% or more, which is not preferable.

[0040] The recording material is required to have a thermal condition that the weight loss in the main weight loss process in the thermogravimetric analysis is steep with respect to the temperature. This is because the organic material film is decomposed in the main weight reduction process, causing a decrease in film thickness and a change in optical constant, thereby forming a recording portion in an optical sense.
Therefore, when the weight loss in the main weight loss process is gentle with respect to the temperature, the weight loss is formed over a wide temperature range, which is extremely disadvantageous when a high-density recording portion is formed. For the same reason, when a material having a plurality of weight loss processes is used, it is disadvantageous for high density. In the present invention, among several weight loss processes, the one with the largest weight loss rate is referred to as the main weight loss process.

In the present invention, the slope of the weight loss is determined as follows. As shown in FIG. 4, the organic material of mass M _o in a nitrogen atmosphere, it is heated at 10 ° C. / min. As the temperature rises, the mass decreases by a small amount, and shows a weight loss line substantially in a straight line a-b. When a certain temperature is reached, a sharp weight loss occurs, and a weight loss occurs substantially along a straight line cd. Further, if the temperature is continuously increased, the rapid weight loss ends, and the weight decreases substantially along the straight line ef.
Now, let the temperature at the intersection of the straight line ab and the straight line cd be T ₁
(° C.), the residual weight with respect to the initial mass M _o is m ₁ (%), and the temperature at the intersection of the straight line cd and the straight line ef is T
₂ (° C.), and the residual weight with respect to the initial mass M _o is m ₂ (%). The weight loss start temperature is T ₁ , the weight loss end temperature is T ₂ ,
The slope of weight loss is a value represented by (m ₁ −m ₂ ) (%) / (T ₂ −T ₁ ) (° C.), and the weight loss rate with respect to the initial weight is (m ₁ −m ₂ ) (% ).

Based on the above definition, the recording material used for the optical recording medium preferably has a weight loss gradient of 2% / ° C. or more in the main weight loss process. If a recording material having a weight loss slope of less than 2% / ° C. is used, the width of the recording portion becomes large, and it becomes difficult to form a short recording portion, which is not suitable for an optical recording medium.

The weight reduction rate in the main weight loss process is as follows:
It is preferably at least 30%. If it is less than 30%, there is a possibility that good recording modulation and recording sensitivity cannot be obtained. Further, the condition required for the thermal characteristics is that the weight loss starting temperature T
₁ needs to be in a certain temperature range. Specifically, the weight loss start temperature is 350 ° C. or less, preferably 20 ° C.
It is desirable to be in the range of 0 to 350 ° C. If the temperature at which the weight loss starts is 350 ° C. or higher, the power of the recording laser beam becomes high, which is impractical. If the temperature is 200 ° C. or lower, the recording stability deteriorates such as reproduction deterioration.

4) Reflection Layer The reflection layer can be made of a metal or semi-metal which is highly resistant to corrosion and can provide a high reflectance by itself. Examples of materials include Au,
Ag, Al, Cr, Ni, Fe, Sn and the like.
Au, Ag, and Al are most preferable in terms of reflectivity and productivity. These metals and metalloids may be used alone.
More than one kind of alloy may be used. Examples of the film forming method include vapor deposition and sputtering, and the film thickness is 50 to 50.
00 °, preferably 100-3000 °.

5) Protective Layer, Hard Coat Layer on Substrate Surface The protective layer or hard coat layer on the substrate surface protects the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc. and preserves the recording layer (reflection / absorption layer). It is used for the purpose of improving the stability and the reflectance. For these purposes, the materials shown in the undercoat layer can be used. Also,
As an inorganic material, SiO, SiO _{2 and the} like can also be used, and as an organic material, polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin,
Thermosoftening and heat melting resins such as natural rubber, styrene-butadiene resin, chloroprene rubber, wax, alkyd resin, drying oil, and rosin can also be used. Among the above materials, the most preferable one for the protective layer or the hard coat layer on the substrate surface is an ultraviolet curable resin having excellent productivity. The thickness of the protective layer or the hard coat layer on the substrate surface is 0.01 to 30 μm.
m, preferably 0.05 to 10 μm.

In the present invention, as in the case of the recording layer, the intermediate layer, the protective layer and the hard coat layer on the substrate have a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant and a plasticizer. Agents and the like can be contained.

[0047]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 On an injection molded polycarbonate substrate having a thickness of 0.6 mm,
1600mm depth, half width 0.28μ with photopolymer
m, a track having a track pitch of 0.74 μm, and a compound specific example No. A methyl cellosolve solution of No. 1 was spin-coated, and a recording layer having a thickness of 500 ° was provided to obtain a recording medium.

Examples 2 to 6 In Example 1, the specific compound No. Instead of 1,
Compound specific example No. 2 No. 3, No. 4, no. 5,
No. Except that Sample No. 6 was used, recording media of Examples 2 to 6 were obtained in the same manner as Example 1.

Comparative Example 1 In Example 1, the specific compound No. A recording medium of Comparative Example 1 was obtained in the same manner as in Example 1, except that the compound represented by the following formula (VI) was used instead of 1.

Embedded image

Using the recording media of Examples 1 to 6 and Comparative Example 1, recording was performed by irradiating light from a substrate under the following recording conditions, and then the C / N ratio and reflectivity were determined by the reproduction light at the recording position. It was measured. Table 4 shows the results. Recording conditions: Laser oscillation wavelength 635 nm Recording frequency 3.8 MHz Recording linear speed 3.4 m / sec Reproduction conditions: Laser oscillation wavelength 650 nm Reproduction power 0.8 mW continuous light Scanning bandwidth 30 KHz Light resistance test conditions: Light resistance test 40,000 Lux, Xe Light, continuous irradiation for 20 hours Storage test 85 ℃, 85%, leave for 500 hours

[0052]

[Table 4]

Example 7 Compound No. No. 1 was prepared on a 0.6 mm-thick injection-molded polycarbonate substrate having a guide groove with a depth of 1600 mm, a half width of 0.24 μm and a track pitch of 0.74 μm. 7 was dissolved in a mixed solution of methylcyclohexane, 2-methoxyethanol, and methylethylketone, and spin-coated to form a recording layer having a thickness of 800 °. Then, a reflective layer of 1500 ° of gold was provided on the recording layer by a sputtering method. A protective layer having a thickness of 5 μm was formed by using an acrylic photopolymer thereon to obtain a recording medium.

Examples 8 to 12 In Example 7, the specific compound Nos. Compound Specific Example No. 7 in place of Compound No. 7 was used. 8, no. 9, No. 10,
No. 11, No. Example 7 except that No. 12 was used.
In the same manner as in the above, recording media of Examples 8 to 12 were obtained.

Comparative Example 2 In Example 7, the specific compound No. A recording medium of Comparative Example 2 was obtained in the same manner as in Example 7, except that the compound represented by the formula (VI) used in Comparative Example 1 was used instead of 7.

EFM signals were recorded on the recording media of Examples 7 to 12 and Comparative Example 2 while tracking using a semiconductor laser beam having an oscillation wavelength of 650 nm and a beam diameter of 1.0 μm (linear velocity: 3.0 m / sec, shortest Mark length 0.4 μm),
Reproduction was performed with continuous light (reproduction power 0.7 mW) of a semiconductor laser having an oscillation wavelength of 650 nm, and a reproduction waveform was observed. Table 5 shows the results.

[0057]

[Table 5]

Example 13 A compound represented by the above formula (VI) was placed on a 1.2 mm thick injection molded polycarbonate substrate having a guide groove with a depth of 1500 °, a half width of 0.26 μm and a track pitch of 0.74 μm. Compound specific example No. 13 and the weight ratio (1 /
1) Dissolved in a mixed solvent of methylcyclohexane, 2-methoxyethanol, methyl ethyl ketone, and tetrahydrofuran, and applied with a spinner to form a recording layer having a thickness of 1700 °, and then formed a reflective layer of 2000 ° gold by a sputtering method. Further, a protective layer having a thickness of 5 μm was formed thereon using an acrylic photopolymer to obtain a recording medium.

Examples 14 to 16 In Example 13, the specific compound Nos. Compound Specific Example No. 13 in place of Compound No. 13 was used. 14, No. 15, N
o. Recording media of Examples 14 to 16 were obtained in the same manner as in Example 13 except that Sample No. 16 was used.

Examples 17 to 20 In Example 13, the specific compound Nos. Compound Specific Example No. 13 in place of Compound No. 13 was used. 17, No. 18, N
o. 19, no. Example 1 was carried out in the same manner as in Example 13 except that Compound 20 was used and a compound represented by the following formula (VII) was used instead of the compound represented by the formula (VI).
7 to 20 recording media were obtained.

[0061]

Embedded image

Comparative Examples 3 and 4 In Example 13, the recording layers were each replaced by the general formula (V)
Recording media of Comparative Examples 3 and 4 were obtained in the same manner as in Example 13 except that only the compound represented by I) was used, and only the compound represented by the general formula (VII) was used.

Using a semiconductor laser beam having an oscillation wavelength of 780 nm and a beam diameter of 1.6 μm on the recording media of Examples 13 to 20 and Comparative Examples 3 and 4, an EFM signal was recorded while tracking (linear velocity of 1.4 m / sec). ), Reproduction was performed with continuous light of the laser and a semiconductor laser having an oscillation wavelength of 650 nm and a beam diameter of 1.0 μm, and a reproduction waveform was observed. Table 6 shows the results.
Shown in

[0064]

[Table 6]

[0065]

According to the first aspect of the present invention, there is provided an optical recording medium comprising, in a recording layer, at least one kind of an azo compound represented by the general formula (I) and an azo metal chelate compound comprising a metal or a salt thereof. Since it has high light absorption and light reflection at a wavelength of 700 nm or less, 700 n
It is applicable to the next-generation high-density disk system (DVD-R disk system) using a semiconductor laser of m or less, and is excellent in light resistance and storage stability.

In the optical recording medium of the second aspect, since the types of the metal of the azo metal chelate compound are limited, optical characteristics such as recording sensitivity are further improved.

According to a third aspect of the present invention, there is provided an optical recording medium comprising at least one of the azo metal chelate compounds and an organic dye having a maximum absorption wavelength at 680 to 750 nm in a recording layer. Recording / reproducing with the system and the next generation high density optical disc system (DV
(D-R disc system), it is possible to reproduce recorded information.

The optical recording medium according to claim 4 is 680 to 750.
Since at least one of a cyanine dye, a phthalocyanine dye and an azo metal chelate dye was selected as an organic dye having a maximum absorption wavelength in nm, high-quality signal characteristics can be recorded and reproduced with the current system, and the next generation Reproduction is possible even with a high-density disk system (DVD-R disk system).

The optical recording medium according to claim 5 has a recording / reproducing wavelength ±
The refractive index n of the recording layer single layer with respect to light in the wavelength region of 5 nm is 1.5 ≦ n ≦ 3.0, and the extinction coefficient k is 0.02 ≦ k.
Since ≦ 0.2, high-quality signal characteristics can be recorded.

According to the optical recording medium of the sixth aspect, in the thermogravimetric analysis of the organic dye, the slope of the weight loss with respect to the temperature in the main weight loss process is 2.
% / ° C. or more, high-quality signal characteristics can be recorded.

According to the optical recording medium of the present invention, the thermogravimetric analysis of the organic dye shows that the total weight loss in the main weight loss process is 30% or more and the temperature at which the weight loss starts is 350 ° C. or less. The signal characteristics of quality can be recorded.

In the optical recording medium according to the present invention, the track pitch on the substrate is 0.7 to 0.8 μm and the groove width is 0.20 to 0.36 μm in half width. The signal characteristics of quality can be recorded.

[Brief description of the drawings]

FIGS. 1A to 1D are diagrams showing examples of a layer configuration as a general write-once optical recording medium applicable to the recording medium of the present invention.

FIGS. 2A to 2C are diagrams showing examples of a layer configuration for a high-reflectance optical recording medium (CD-R) applicable to the recording medium of the present invention.

FIGS. 3A to 3C are diagrams showing examples of layer configurations for a large-capacity high-reflection optical recording medium (DVD-R) applicable to the recording medium of the present invention.

FIG. 4 is a diagram showing a thermal decomposition curve of an organic dye.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Recording layer (organic dye layer) 3 Intermediate layer 4 Protective layer 5 Hard coat layer 6 Reflective layer 7 Protective substrate 8 Adhesive layer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tatsuya Tomura 1-3-6 Nakamagome, Ota-ku, Tokyo Stock inside Ricoh Company (72) Inventor Yasuhiro Higashi 1-3-6 Nakamagome, Ota-ku, Tokyo Share F-term in Ricoh Company (reference) 2H111 EA03 EA12 EA22 EA31 EA39 EA40 FA01 FB42 FB43 FB45 4C031 JA20 NA06 5D029 JA04 JC05 JC11 JC17

Claims (8)

[Claims] 1. An optical recording medium comprising a recording layer provided on a substrate, wherein said recording layer contains at least one azo metal chelate compound comprising an azo compound represented by the following general formula (I) and a metal or a salt thereof. An optical recording medium characterized by containing. Embedded image (Wherein, R ₁ and R ₂ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, and R ₁ and R ₂ are linked to form a ring. R _{3 to} R ₁₁ each independently represent a hydrogen atom,
Halogen atom, nitro group, cyano group, hydroxyl group, carboxy group, amino group, carbamoyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted heterocyclic residue, substituted or unsubstituted Alkyloxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted alkylamino group, substituted or unsubstituted arylamino group, substituted or unsubstituted alkyloxycarbonyl group, substituted or unsubstituted aryloxycarbonyl Group, a substituted or unsubstituted alkylcarbonylamino group, a substituted or unsubstituted arylcarbonylamino group, a substituted or unsubstituted alkylcarbamoyl group, a substituted or unsubstituted arylcarbamoyl group, or a substituted or unsubstituted alkenyl group , R ₃ and R _{4, 4} and R ₁ or R _2, R ₅ and R ₁ or R _2, R ₆ and R _7, R ₇ and R _8, R ₈ and R _9, R ₉ and R _10, R
₁₀ and R ₁₁ may be linked to form a ring. X is a hydroxy group, an alkyloxy group, an aryloxy group, a carboxy group, an alkyloxycarbonyl group, an aryloxycarbonyl group, an amino group, an alkylcarbonylamino group, an arylcarbonylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, Represents a carbamoyl group, an alkylcarbamoyl group, an arylcarbamoyl group, a sulfo group, a sulfino group, a sulfeno group, an aminosulfonyl group, an alkylsulfonyl group, or an arylsulfonyl group. ) 2. The optical recording medium according to claim 1, wherein the metal atom of the azo metal chelate compound is at least one of aluminum, chromium, manganese, cobalt, nickel, copper and zinc. 3. The optical recording medium according to claim 1, wherein the recording layer comprises the azo metal chelate compound and 680-7.
An optical recording medium comprising a mixed layer with a dye having a maximum absorption wavelength at 50 nm. 4. The optical recording medium according to claim 3, wherein
An optical recording medium, wherein the dye having a maximum absorption wavelength at 80 to 750 nm is at least one of a cyanine dye, a phthalocyanine dye, and an azo metal chelate compound. 5. The optical recording medium according to claim 1, wherein a single layer of the recording layer has a refractive index n of 1.5 ≦ n ≦ 3.0 with respect to light in a wavelength range of ± 5 nm in a recording / reproducing wavelength. And an extinction coefficient k is 0.02 ≦ k ≦ 0.2. 6. The optical recording medium according to claim 1, wherein, in thermogravimetric analysis of the organic dye, a slope of weight loss with respect to temperature in a main weight loss process is 2% / ° C. or more. Optical recording medium. 7. The optical recording medium according to claim 1, wherein, in thermogravimetric analysis of the organic dye, the total weight loss in the main weight loss process is 30% or more, and the weight loss start temperature is 350 ° C.
An optical recording medium characterized by the following. 8. The optical recording medium according to claim 1, wherein a track pitch on the substrate is 0.7-0.
8 μm, and the groove width is half width, 0.20 to 0.36 μm.
m, an optical recording medium.