JP2005255728A - Azo metal chelate compound and optical recording medium using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording medium capable of recording and reproduction with short-wavelength laser beams at a wavelength of 520-690 nm, excellent in durability, and suitable for high-density and high-speed recording. <P>SOLUTION: The metal chelate compound is formed from an azo compound represented by formula (1) and a metal salt. In formula (1), ring A and X are each independently an optionally substituted aromatic heterocyclic ring; and ring B is an aromatic hydrocarbon ring. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical recording medium using an azo metal chelate compound and capable of recording and reproducing at a higher density than in the past.

  A CD-R using an organic dye as a recording material is widely known as a medium capable of recording and reproducing data such as images, videos, and sounds. At present, with the increase in the amount of data to be handled, it is desired that an optical recording medium capable of recording and reproducing a large volume compared with a CD-R is desired. In particular, a DVD-R using an organic dye as a recording material is similar to a CD-R. Developed and commercialized as the next generation medium.

  In DVD-R, in order to perform high-density recording, the transmission wavelength of laser light is near 630 nm to 680 nm and shorter than in the case of CD-R. Examples of such dyes for organic dye-based optical recording media for short wavelengths include cyanine, azo, porphyrin dyes, indigo, dioxazine, coumarin, perylene, naphtholactam, triphenylmethane, subphthalocyanine, dibenzopyran, dipyrromethene, and the like. Has been proposed.

  However, durability problems, especially problems that are specific to short-wavelength applications, such as where small pits should be opened with focused laser light, have a large impact on the surroundings, and jitter deterioration due to pit formation with a large distribution , Deterioration of radial crosstalk, deterioration of modulation due to extremely small pits, or inappropriate optical constant (refractive index, extinction coefficient) at the target laser wavelength There is still room for improvement in the reduction in reflectance and the deterioration in sensitivity caused by the selection of the organic dye as the recording layer.

  Furthermore, as seen in the increase in recording speed in CD-R, an optical recording medium corresponding to 16 times speed, 4 times speed, 8 times speed or more is desired in DVD-R as compared with the standard recording speed. ing. Also, it is desired to realize an optical recording medium that can perform good recording regardless of whether the recording speed is a standard recording speed or a high recording speed.

  However, with the increase in recording speed, it becomes difficult to control the decomposition behavior of the recording layer dye during pit formation, which causes problems such as deterioration in recording sensitivity and deterioration in jitter. In addition, the recording characteristics in standard speed recording and the recording characteristics in high speed recording are in a trade-off relationship, and in order to satisfy one of the characteristics, it is necessary to sacrifice the other characteristic. ing.

  The object of the present inventor is to record and reproduce with a short wavelength laser having a wavelength of 520 to 690 nm, and has good recording characteristics not only at standard recording speed but also at high speed recording, and excellent in durability. The object is to provide a high-density optical recording medium.

  As a result of intensive studies to solve the above problems, the present inventors have not only excellent recording characteristics and durability in standard speed recording but also high speed by using an azo metal chelate compound having a specific structure. The inventors have found that an optical recording medium capable of recording can be obtained, and have completed the present invention.

That is, the present invention
[1] A metal chelate compound formed from two or more azo compounds which may be the same or different from each other and a divalent or higher metal salt, and at least one of the azo compounds is represented by the following general formula: A metal chelate compound characterized by being an azo compound represented by (1),

(In the formula, rings A and X each independently represent a heterocyclic ring optionally having a substituent, and ring B represents an aromatic hydrocarbon ring.)

[2] In general formula (1), ring A may have a substituent, an imidazolyl group, an oxazoyl group, a thiazoyl group,
Pyrazoyl group, isoxazoyl group, isothiazoyl group,
The metal chelate compound according to [1], which is a triazoyl group, a thiadiazoyl group, an isothiadiazoyl group, or a pyridyl group;

[3] In the general formula (1), X may have a substituent, an imidazolyl group, an oxazoyl group, a thiazoyl group,
Pyrazoyl group, isoxazoyl group, isothiazoyl group,
The metal chelate compound according to [1], which is a furyl group, a thienyl group, or a pyridyl group;

[4] A metal chelate compound formed from two azo compounds represented by the following general formula (2), which may be the same or different from each other, and a metal salt of Ni, Co or Cu,

(Wherein Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ , Y ₆ and Y ₇ are each independently a carbon atom, nitrogen atom, oxygen atom, sulfur atom, C—R ₄ , N—R ₄ . (R ₄ is a hydrogen atom, a halogen atom, a formyl group, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an amino group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or 2 carbon atoms. -7 acyl group, alkenyl group having 2 to 6 carbon atoms, hydroxyalkyl group having 1 to 6 carbon atoms, alkoxycarbonyl group having 2 to 7 carbon atoms, alkylamino group having 1 to 12 carbon atoms, 3 to 7 carbon atoms R ₁ , R _2, and R ₃ are each an alkoxycarbonylalkyl group, a C 1-6 alkylthio group, a C 1-6 alkylsulfonyl group, or a C 2-6 alkylcarbonylamino group. Germany Hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 16 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, _{R 1} and _{R 2} or _{R 3} R ₂ and R ₃ may be linked to form a 5- to 6-membered ring.)

[5] In an optical recording medium having at least a recording layer and a reflective layer on a substrate, the recording layer contains at least one metal chelate compound according to any one of [1] to [4]. Media.

  By using the novel metal chelate compound of the present invention as a recording layer, a write-once type optical recording medium suitable for high-density and high-speed recording that can be recorded and reproduced with a laser having a wavelength of 520 to 690 nm and has excellent durability It becomes possible to provide.

  Hereinafter, the present invention will be described in detail.

  The metal chelate compound of the present invention is a metal chelate compound formed from two or more azo compounds which may be the same or different from each other and a metal salt having two or more valences, At least one of the metal chelate compounds is an azo compound represented by the following general formula (1).

  In the azo compound forming the metal chelate compound of the present invention, the azo compound other than the azo compound represented by the following general formula (1) may be a known azo compound, and is not particularly limited.

  As the azo compound forming the metal chelate compound in the present invention, the azo compound represented by the following general formula (1) will be described more specifically.

(In the formula, rings A and X each independently represent a heterocyclic ring optionally having a substituent, and ring B represents an aromatic hydrocarbon ring.)

In the azo compound represented by the general formula (1), the rings A and X are not particularly limited as long as they are heterocyclic rings, but are preferably aromatic heterocyclic rings, and these heterocyclic rings are substituents. You may have. As the rings A and X, a 5-membered ring or a 6-membered ring is preferable, and in the ring A, an imidazolyl group, an oxazoyl group, a thiazoyl group,
Pyrazoyl group, isoxazoyl group, isothiazoyl group,
Triazoyl group, thiadiazoyl group, isothiadiazoyl group, pyridyl group,
In X, an imidazolyl group, an oxazoyl group, a thiazoyl group,
Pyrazoyl group, isoxazoyl group, isothiazoyl group,
A furyl group, a thienyl group, and a pyridyl group; Specific examples include the following structures.

In which R ₅ may all be the same or different,
Hydrogen atom; halogen atom such as fluorine atom, chlorine atom, bromine atom; formyl group; hydroxyl group; carboxyl group; cyano group; nitro group;
Methyl, trifluoromethyl, ethyl, pentafluoroethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, cyclo An alkyl group having 1 to 6 carbon atoms such as propyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group;
C1-C6 alkoxy such as methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, tert-butoxy group, sec-butoxy group, n-pentyloxy group, n-hexyloxy group, etc. Group;
An acyl group having 2 to 7 carbon atoms such as acetyl group, propiol group, butyryl group, isobutyryl group, valeryl group, isovaleryl group, pivaloyl group, hexanoyl group, heptanoyl group;
An alkenyl group having 2 to 6 carbon atoms such as vinyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, cyclopentenyl group, cyclohexenyl group;
A hydroxyalkyl group having 1 to 6 carbon atoms such as a hydroxymethyl group and a hydroxyethyl group;
Methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, isopropoxycarbonyl group, n-butoxycarbonyl group, tert-butoxycarbonyl group, sec-butoxycarbonyl group, n-pentyloxycarbonyl group, n-hexyloxycarbonyl group An alkoxycarbonyl group having 2 to 7 carbon atoms, such as
1 to 12 carbon atoms such as methylamino group, ethylamino group, n-propylamino group, n-butylamino group, dimethylamino group, diethylamino group, di-n-propylamino group, di-n-butylamino group, etc. An alkylamino group;
An alkoxycarbonylalkyl group having 3 to 7 carbon atoms such as a methoxycarbonylmethyl group, an ethoxycarbonylmethyl group, an n-propoxycarbonylmethyl group, an isopropoxycarbonylethyl group;
An alkylthio group having 1 to 6 carbon atoms such as methylthio group, ethylthio group, n-propylthio group, tert-butylthio group, sec-butylthio group, n-pentylthio group, n-hexylthio group;
Carbon such as methylsulfonyl group, ethylsulfonyl group, n-propylsulfonyl group, isopropylsulfonyl group, n-butylsulfonyl group, tert-butylsulfonyl group, sec-butylsulfonyl group, n-pentylsulfonyl group, n-hexylsulfonyl group 1-6 alkylsulfonyl groups;
Methylcarbonylamino group, ethylcarbonylamino group, n-propylcarbonylamino group, isopropylcarbonylamino group, n-butylcarbonylamino group, tert-butylcarbonylamino group, sec-butylcarbonylamino group, n-pentylcarbonylamino group, etc. Represents an alkylcarbonylamino group having 2 to 6 carbon atoms.

  Here, examples of the substituent that the rings A and X may have include a halogen atom, a formyl group, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an amino group, and a substituent. A good alkyl group, an alkoxy group which may have a substituent, an acyl group which may have a substituent, an alkenyl group which may have a substituent, and a hydroxy which may have a substituent An alkyl group, an alkoxycarbonyl group which may have a substituent, an alkylamino group which may have a substituent, an alkoxycarbonylalkyl group which may have a substituent, and a substituent. And an alkylthio group which may have a substituent, an alkylsulfonyl group which may have a substituent, and an alkylcarbonylamino group which may have a substituent.

Preferably, a halogen atom, formyl group, hydroxyl group, carboxyl group, cyano group, nitro group, amino group, alkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, acyl group having 2 to 7 carbon atoms , An alkenyl group having 2 to 6 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, an alkylamino group having 1 to 12 carbon atoms, and an alkoxycarbonylalkyl group having 3 to 7 carbon atoms , An alkylthio group having 1 to 6 carbon atoms, an alkylsulfonyl group having 1 to 6 carbon atoms, and an alkylcarbonylamino group having 2 to 6 carbon atoms,
More specifically, halogen atoms such as fluorine atom, chlorine atom, bromine atom;
Hydroxyl group; carboxyl group; cyano group; nitro group; amino group;
Methyl, trifluoromethyl, ethyl, pentafluoroethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, cyclo An alkyl group having 1 to 6 carbon atoms such as propyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group;
C1-C6 alkoxy such as methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, tert-butoxy group, sec-butoxy group, n-pentyloxy group, n-hexyloxy group, etc. Group;
An acyl group having 2 to 7 carbon atoms such as acetyl group, propiol group, butyryl group, isobutyryl group, valeryl group, isovaleryl group, pivaloyl group, hexanoyl group, heptanoyl group;
An alkenyl group having 2 to 6 carbon atoms such as vinyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, cyclopentenyl group, cyclohexenyl group;
A hydroxyalkyl group having 1 to 6 carbon atoms such as a hydroxymethyl group and a hydroxyethyl group;
Methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, isopropoxycarbonyl group, n-butoxycarbonyl group, tert-butoxycarbonyl group, sec-butoxycarbonyl group, n-pentyloxycarbonyl group, n-hexyloxycarbonyl group An alkoxycarbonyl group having 2 to 7 carbon atoms, such as
1 to 12 carbon atoms such as methylamino group, ethylamino group, n-propylamino group, n-butylamino group, dimethylamino group, diethylamino group, di-n-propylamino group, di-n-butylamino group, etc. An alkylamino group;
An alkoxycarbonylalkyl group having 3 to 7 carbon atoms such as a methoxycarbonylmethyl group, an ethoxycarbonylmethyl group, an n-propoxycarbonylmethyl group, an isopropoxycarbonylethyl group;
An alkylthio group having 1 to 6 carbon atoms such as methylthio group, ethylthio group, n-propylthio group, tert-butylthio group, sec-butylthio group, n-pentylthio group, n-hexylthio group;
Carbon such as methylsulfonyl group, ethylsulfonyl group, n-propylsulfonyl group, isopropylsulfonyl group, n-butylsulfonyl group, tert-butylsulfonyl group, sec-butylsulfonyl group, n-pentylsulfonyl group, n-hexylsulfonyl group 1-6 alkylsulfonyl groups;
Methylcarbonylamino group, ethylcarbonylamino group, n-propylcarbonylamino group, isopropylcarbonylamino group, n-butylcarbonylamino group, tert-butylcarbonylamino group, sec-butylcarbonylamino group, n-pentylcarbonylamino group, etc. An alkylcarbonylamino group having 2 to 6 carbon atoms;
Is mentioned.

  In the azo compound represented by the general formula (1), the ring B is an aromatic hydrocarbon ring, and these aromatic hydrocarbon rings may have a substituent. As ring B, a 6-membered ring is preferable, and in particular, the following general formula (3)

で表わされる構造が好ましい。
式中、Ｒ_１、Ｒ_２およびＲ_３は水素原子、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数６〜１６のアリール基、炭素数２〜６のアルケニル基を表わし、Ｒ_１とＲ_２若しくはＲ_３、Ｒ_２とＲ_３は連結して５〜６員環を形成してもよい。Ｘは前記と同じ意味を表わす。

The structure represented by is preferable.
In the formula, R ₁ , R ₂ and R ₃ are a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 16 carbon atoms, and an alkenyl group having 2 to 6 carbon atoms. R ₁ and R ₂ or R ₃ , R ₂ and R ₃ may be linked to form a 5- to 6-membered ring. X represents the same meaning as described above.

  Specific examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n- A hexyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and the like can be mentioned. Specific examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, n -Butoxy group, tert-butoxy group, sec-butoxy group, n-pentyloxy group, n-hexyloxy group and the like. Specific examples of the aryl group having 6 to 16 carbon atoms include phenyl group, tolyl group, Xylyl group, naphthyl group, and the like. Specific examples of the alkenyl group having 2 to 6 carbon atoms include vinyl group, propenyl group, butenyl group, pentene group, and the like. Group, hexenyl group, cyclopentenyl group, cyclohexenyl group and the like.

As a specific example in which R ₂ and R ₃ are linked to form a 5- to 6-membered ring,

等の基が挙げられる。

And the like.

As a specific example in which R ₁ and R ₂ or R ₃ are linked to form a 5- to 6-membered ring,

等の基が挙げられる。

And the like.

In the formula, R ₂ , R ₃ , and X represent the same meaning as described above, and R ₆ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an aryl having 6 to 16 carbon atoms. Group represents an alkenyl group having 2 to 6 carbon atoms.

  Specific examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n- A hexyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and the like can be mentioned. Specific examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, n -Butoxy group, tert-butoxy group, sec-butoxy group, n-pentyloxy group, n-hexyloxy group and the like. Specific examples of the aryl group having 6 to 16 carbon atoms include phenyl group, tolyl group, Xylyl group, naphthyl group, and the like. Specific examples of the alkenyl group having 2 to 6 carbon atoms include vinyl group, propenyl group, butenyl group, pentene group, and the like. Group, hexenyl group, cyclopentenyl group, cyclohexenyl group and the like.

  Here, examples of the substituent that the ring B may have include the same substituents as those substituted on the aforementioned rings A and X, and specific examples thereof include the same substituents as described above. .

  In the present invention, specific examples of the metal salt that forms a chelate compound with an azo compound include Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ru, Rh, and Pd. In, Sn, Hf, Os, Pt, or Hg, azo metal chelate compounds of Co, Ni, and Cu are particularly preferable as optical recording materials because of their excellent optical characteristics.

  As the azo compound forming the metal chelate compound of the present invention, the azo compound represented by the following general formula (2) will be described more specifically.

(Wherein Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ , Y ₆ and Y ₇ are each independently a carbon atom, nitrogen atom, oxygen atom, sulfur atom, C—R ₄ , N—R ₄ . (R ₄ is a hydrogen atom, a halogen atom, a formyl group, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an amino group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or 2 carbon atoms. -7 acyl group, alkenyl group having 2 to 6 carbon atoms, hydroxyalkyl group having 1 to 6 carbon atoms, alkoxycarbonyl group having 2 to 7 carbon atoms, alkylamino group having 1 to 12 carbon atoms, 3 to 7 carbon atoms R ₁ , R _2, and R ₃ are each an alkoxycarbonylalkyl group, a C 1-6 alkylthio group, a C 1-6 alkylsulfonyl group, or a C 2-6 alkylcarbonylamino group. Germany Hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 16 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, _{R 1} and _{R 2} or _{R 3} R ₂ and R ₃ may be linked to form a 5- to 6-membered ring.)

In the general formula (2), Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ , Y ₆ and Y ₇ are each independently a carbon atom, nitrogen atom, oxygen atom, sulfur atom, C—R ₄ , N— represents R _{4, R 4} is a hydrogen atom, a halogen atom, a formyl group, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an amino group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms , An acyl group having 2 to 7 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, a hydroxyalkyl group having 1 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, an alkylamino group having 1 to 12 carbon atoms, carbon A C3-C7 alkoxycarbonylalkyl group, a C1-C6 alkylthio group, a C1-C6 alkylsulfonyl group, and a C2-C6 alkylcarbonylamino group are represented.

R ₁ , R ₂ and R ₃ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 16 carbon atoms, or an aryl group having 2 to 6 carbon atoms. Represents an alkenyl group, R ₁ and R ₂ or R ₃ , R ₂ and R ₃ may be linked to form a 5- to 6-membered ring.

Specific examples of the substituents in R ₁ , R ₂ , R ₃ and R ₄ include the same substituents as described above.

  Examples of particularly preferred azo compounds in the general formula (2) include the following.

  Moreover, the following are mentioned as a particularly preferable example of the metal chelate compound formed from the azo compound represented by the general formula (2) and a metal salt.

  The metal chelate compound of the present invention has the general formula (4)

(Wherein A is the same as described above) is diazotized by a known method to give a compound of the general formula (5)

The azo compound represented by the general formula (1) synthesized by reacting with a coupling component represented by the formulas (B and X are the same as above) is converted into a metal compound in an organic solvent such as methyl alcohol, tetrahydrofuran and acetone. It can be obtained by adding a methanol solution or an aqueous solution.

  The metal chelate compound of the present invention is formed from two or more azo compounds and a divalent or higher metal salt, and the azo compounds may be the same or different from each other. A metal chelate compound formed from a different azo compound and a divalent or higher valent metal salt is obtained by mixing a metal compound in a mixture of different azo compounds obtained by the above method in an organic solvent such as methyl alcohol, tetrahydrofuran, and acetone. It can be obtained by adding a methanol solution or an aqueous solution.

  A specific configuration of the optical recording medium in the present invention will be described below.

  The optical recording medium refers to both a reproduction-only optical reproduction medium in which information is recorded in advance and an optical recording medium in which information can be recorded and reproduced. However, here, as an example, an optical recording medium that can record and reproduce the latter information, particularly an optical recording medium having a recording layer and a reflective layer on a substrate will be described. The optical recording medium of the present invention has a bonding structure as shown in FIG. That is, the recording layer 2 is formed on the substrate 1, the reflective layer 3 is provided in close contact with the recording layer 2, and the substrate 5 is bonded thereon with the adhesive layer 4 interposed therebetween. However, another layer may be provided below or on the recording layer 2, and another layer may be provided on the reflective layer 3. Here, in order to be compatible with an existing DVD, a disk-shaped substrate having a thickness of 0.6 mm, an outer diameter of 120 mmΦ, and an inner diameter of 15 mmφ is bonded.

  Next, the required characteristics of each layer constituting the recording medium of the present invention and its constituent materials will be described.

1) Substrate The material of the substrate may be basically transparent at the wavelengths of recording light and reproducing light. For example, an acrylic resin such as polycarbonate resin, vinyl chloride resin or polymethyl methacrylate, a polymer material such as polystyrene resin or epoxy resin, or an inorganic material such as glass is used. These substrate materials are formed into a disk shape by an injection molding method or the like. The substrate surface may have pregrooves and prepits representing recording positions, and prepits for partial reproduction-only information. These pregrooves and prepits are usually transferred and applied from a stamper master during substrate production by an injection molding method or the like. Moreover, you may produce by the laser cutting method (prelight) and 2P (Photo Polymer) method.

  The groove pitch of the substrate is 0.7 μm to 1.0 μm, and the groove depth is 100 nm to 200 nm, preferably 140 nm to 185 nm. The groove width is 0.25 μm to 0.40 μm, preferably 0.30 μm to 0.35 μm. When the groove depth is less than 100 nm, it tends to be difficult to obtain a push-pull signal amplitude for tracking. When the groove depth exceeds 200 nm, the transfer process at the time of injection molding is not practical for production. Further, when the groove width is less than 0.25 μm, the crosstalk tends to deteriorate, and when it exceeds 0.4 μm, the transfer process at the time of injection molding is not practical in production. These groove shapes are obtained from a diffracted light analysis by He-Cd laser irradiation or a profile such as AFM.

2) Recording layer In the present invention, a recording layer is provided on a substrate. The recording layer of the present invention is formed from an azo compound represented by the general formula (1) having a λmax of around 450 nm to 630 nm and a metal salt. Containing metal chelate compounds. Among them, an appropriate optical constant for the recording and reproducing laser wavelength selected from 520 nm to 690 nm (the optical constant is expressed by a complex refractive index (n + ki). N and k in the formula are a real part n and an imaginary part. It is necessary to have a coefficient corresponding to k, where 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. When n is less than 1.8, the reflectivity and signal modulation necessary for accurate signal reading cannot be obtained, and even if k exceeds 0.40, the reflectivity decreases and a good reproduction signal is obtained. Not only is the signal easily changed by the reproduction light, but it is not suitable for practical use. In consideration of this feature, an organic dye having a preferable optical constant at a target laser wavelength is selected and a recording layer is formed, so that a medium having high reflectance and high sensitivity can be obtained. .

  The metal chelate compound formed from the azo compound represented by the general formula (1) and the metal salt used in the present invention has a higher extinction coefficient than that of a normal organic dye, and has an absorption wavelength range by selecting a substituent. Since it can be arbitrarily selected, the optical constant required for the recording layer at the wavelength of the laser beam (n is 1.8 or more, and k is 0.04 to 0.40, preferably n is 2.0 or more. And k satisfies 0.04 to 0.20).

  Furthermore, the metal chelate compound formed from the azo compound represented by the general formula (1) and the metal salt has moderately accelerated decomposition due to heat generated at the time of recording laser irradiation, and has high sensitivity even at high speed recording. Deterioration of pit jitter due to thermal interference can be suppressed sufficiently low, which is extremely useful.

  In the recording layer of the present invention, two or more kinds of metal chelate compounds formed from the azo compound represented by the general formula (1) and a metal salt may be mixed in order to improve recording characteristics and the like. . The mixing ratio of the azo metal chelate compound is not particularly limited, but for the above reasons, the optical constant n is 1.8 or more, preferably 2.0 or more, and k is 0.04 to 0.40. It is preferable to mix so that it may become 0.04-0.20 preferably.

  Further, it may be mixed with a dye other than the above having an absorption maximum at a wavelength of 450 nm to 630 nm and a large refractive index at 520 nm to 690 nm. Specifically, cyanine dyes, squarylium dyes, naphthoquinone dyes, anthraquinone dyes, porphyrin dyes, azaporphyrin dyes, tetrapyraporphyrazine dyes, indophenol dyes, pyrylium dyes, thiopyrylium dyes, Azurenium dyes, triphenylmethane dyes, xanthene dyes, indanthrene dyes, indigo dyes, thioindigo dyes, merocyanine dyes, thiazine dyes, acridine dyes, oxazine dyes, etc. It may be mixed. The mixing ratio of these pigments is about 0.1 to 30%.

  Further, when the metal chelate compound formed from the azo compound represented by the general formula (1) and the metal salt has a small k for recording and reproducing laser wavelengths selected from 520 nm to 690 nm, the recording characteristics In order to improve the above, a light absorbing compound having an absorption maximum at a wavelength of 600 nm to 900 nm may be mixed. Specifically, cyanine dyes, squarylium dyes, naphthoquinone dyes, anthraquinone dyes, porphyrin dyes, azaporphyrin dyes, tetrapyraporphyrazine dyes, indophenol dyes, pyrylium dyes, thiopyrylium dyes, Azurenium dye, triphenylmethane dye, xanthene dye, indanthrene dye, indigo dye, thioindigo dye, merocyanine dye, thiazine dye, acridine dye, oxazine dye, phthalocyanine dye, naphthalocyanine dye There are pigments and the like, and a mixture of a plurality of pigments may be used. The mixing ratio of these pigments is about 0.1 to 30%.

  When forming the recording layer, if necessary, a quencher, a dye decomposition accelerator, an ultraviolet absorber, an adhesive, an endothermic decomposition compound, or the like is mixed, or a compound having such an effect is represented by the general formula ( It can also be introduced as a substituent of a metal chelate compound formed from the azo compound shown in 1) and a metal salt.

  Specific examples of quenchers include acetylacetonate compounds, bisdithio-α-diketone compounds, bisdithiol compounds such as bisphenyldithiol compounds, thiocatechol compounds, salicylaldehyde oxime compounds, thiobisphenolate compounds Metal complexes such as compounds are preferred. Amine compounds are also suitable.

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

  Furthermore, a binder, a leveling agent, an antifoaming agent, etc. can also be used together as needed. 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.

  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, reflectance, recording sensitivity, etc. of the substrate.

  Examples of the method for providing the recording layer include spin coating, spraying, casting, dipping, and other coating methods, sputtering, chemical vapor deposition, and vacuum vapor deposition. The spin coating method is simple and preferable.

  When a coating method such as spin coating is used, the metal chelate compound formed from the azo compound represented by the general formula (1) and the metal salt is 1 to 40% by weight, preferably 3 to 30% by weight. As described above, a coating solution dissolved or dispersed in a solvent is used. In this case, it is preferable to select a solvent that does not damage the substrate. For example, alcohol solvents such as methanol, ethanol, isopropyl alcohol, octafluoropentanol, allyl alcohol, methyl cellosolve, ethyl cellosolve, tetrafluoropropanol, hexane, heptane, octane, decane, cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane Aliphatic or alicyclic hydrocarbon solvents such as, aromatic hydrocarbon solvents such as toluene, xylene, benzene, halogenated hydrocarbon solvents such as carbon tetrachloride, chloroform, tetrachloroethane, dibromoethane, diethyl ether, Ether solvents such as dibutyl ether, diisopropyl ether and dioxane, ketone solvents such as acetone and 3-hydroxy-3-methyl-2-butanone, ethyl acetate and lactic acid Ester solvents such as Le, and water. These may be used alone or in combination.

  If necessary, the dye of the recording layer can be dispersed in a polymer thin film or the like.

  In addition, 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 film thickness of the dye layer is not particularly limited, but the film thickness on the guide grooves (grooves) of the substrate is preferably in the range of 30 nm to 150 nm, and the film thickness between the guide grooves (lands) of the substrate is 10 nm to A range of 80 nm is preferred. If the thickness of the groove exceeds 150 nm, the shortest pit is crushed, which is not preferable. On the other hand, when the thickness is smaller than 30 nm, good recording sensitivity and recording modulation degree cannot be obtained. It is particularly preferable that the film thickness on the land is as thin as possible. The film thickness of these recording layers can be controlled by using a mixture of a plurality of the above organic solvents.

3) Reflective layer A reflective layer having a thickness of preferably 50 nm to 300 nm is formed on the recording layer. As a material for the reflective 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, and Pd metal may be used alone or as an alloy. Is possible. Among these, Au, Al, and Ag have high reflectivity and are suitable as the material for the reflective layer. Other than this, the following may be included. For example, Mg, Se, Hf, V, Nb, Ru, W, Mn, Re, Fe, Co, Rh, Ir, Zn, Cd, Ga, In, Si, Ge, Te, Pb, Po, Sn, Bi, etc. And metals and metalloids. In addition, a material containing Au as a main component is preferable because a reflective layer having a high reflectance can be easily obtained. Here, the main component means that the content is 50% or more. It is also possible to form a multilayer film by alternately stacking a low refractive index thin film and a high refractive index thin film using a material other than metal, and use it as a reflective layer.

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

4) Protective layer 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. Examples of the organic substance include a thermoplastic resin, a thermosetting resin, an electron beam curable resin, and an ultraviolet curable resin. Examples of inorganic substances include SiO ₂ , Si ₃ N ₄ , MgF ₂ , SnO _{2 and the} like. A thermoplastic resin, a thermosetting resin, etc. can be formed by dissolving in an appropriate solvent, applying a coating solution, and drying. The ultraviolet curable resin can be formed by preparing a coating solution as it is or by dissolving in an appropriate solvent, and then applying the coating solution and curing it by irradiating with ultraviolet rays. As the ultraviolet 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 in combination, and may be used not only as a single layer but also as a multilayer film.

  As a method for forming the protective layer, a coating method such as a spin coating method and a casting method, a sputtering method, a chemical vapor deposition method, and the like are used as in the recording layer. Among these, a spin coating method is preferable.

  The thickness of the protective layer is generally in the range of 0.1 μm to 100 μm, but in the present invention, it is 3 μm to 30 μm, more preferably 5 μm to 20 μm.

  A label or the like can be further printed on the protective layer. Alternatively, a protective sheet or substrate may be 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. Further, an ultraviolet curable resin, an inorganic thin film, or the like may be formed on the mirror surface side of the substrate in order to protect the surface and prevent adhesion of dust and the like.

  The laser having a wavelength of 520 nm to 690 nm as used in the present invention is not particularly limited. Examples thereof include a semiconductor laser and a harmonic conversion YAG laser having a wavelength of 532 nm. In the present invention, high-density recording and reproduction are possible at one wavelength or a plurality of wavelengths selected from these.

  Examples of the present invention will be shown below, but the present invention is not limited thereto.

Synthesis of metal chelate compound (AM-1) 0.83 g of the compound represented by the following structural formula (4-a) was dissolved in a mixed solution of 24 g of water and 4.15 g of 36% hydrochloric acid, and nitrous acid at 0-5 ° C. An aqueous solution of 0.48 g of sodium was added dropwise. The mixture was stirred at the same temperature for 1 hour to diazotize. 2.00 g of the compound represented by the following structural formula (5-a), 0.26 g of urea and 2.56 g of sodium acetate were dissolved in 80 g of methanol, and the obtained diazo solution was added dropwise at 0-5 ° C. The mixture was stirred at the same temperature for 3 hours and then left overnight. The precipitated crystals were separated by filtration, washed with water and dried to obtain 2.00 g of a compound represented by the following structural formula (6-a).

  Next, 2.00 g of the compound represented by the formula (6-a) was dissolved in 45 g of methanol, 0.71 g of potassium carbonate and 0.65 g of dimethylsulfuric acid were added, and the mixture was stirred at room temperature for 2 hours. The precipitated crystals were separated by filtration, washed with water and dried to obtain 1.88 g of compound (1-1).

  Next, a solution prepared by dissolving 1.88 g of the compound represented by the formula (1-1) in 80 g of methanol and 16 g of tetrahydrofuran, and dropwise adding a solution of 0.59 g of nickel acetate tetrahydrate in 5 g of methanol at 50 to 55 ° C. The mixture was stirred at the same temperature for 1 hour. After cooling to room temperature, the precipitated crystals were separated by filtration, washed with water and dried to obtain 1.67 g of metal chelate compound (AM-1).

From the following analysis results, it was confirmed to be the target product.
Elemental analysis _{(C 42 H 40 N 18 O} 6 S 2 Ni)

The compound thus obtained showed an absorption maximum at 543.0 nm in a chloroform solution, and the gram extinction coefficient was 1.03 × 10 ⁵ ml / g. cm.

Synthesis of metal chelate compound (AM-3) 1.19 g of the compound represented by the following structural formula (4-a) was dissolved in a mixed solution of 32 g of water and 6.00 g of 36% hydrochloric acid, and nitrous acid was added at 0-5 ° C. An aqueous solution of 0.68 g of sodium was added dropwise. The mixture was stirred at the same temperature for 1 hour to diazotize. A compound represented by the following structural formula (5-b) (3.02 g), urea (0.38 g) and sodium acetate (3.67 g) were dissolved in methanol (120 g), and the obtained diazo solution was added dropwise at 0-5 ° C. The mixture was stirred at the same temperature for 2 hours and left overnight. The precipitated crystals were separated by filtration, washed with water and dried to obtain 3.54 g of a compound represented by the following structural formula (6-b).

  Next, 3.52 g of the compound represented by the formula (6-b) was dissolved in 140 g of acetone, 2.53 g of potassium carbonate and 1.11 g of dimethylsulfuric acid were added, and the mixture was stirred at room temperature for 1 hour. The precipitated crystals were separated by filtration, washed with water and dried to obtain 2.15 g of compound (1-3).

  Next, 2.14 g of the compound represented by the formula (1-3) is dissolved in 40 g of methanol and 40 g of tetrahydrofuran, and a solution obtained by dissolving 0.64 g of nickel acetate tetrahydrate in 8 g of methanol at 50 to 55 ° C. is dropped. The mixture was stirred at the same temperature for 2 hours. After cooling to room temperature, the precipitated crystals were separated by filtration, washed with water and dried to obtain 1.51 g of metal chelate compound (AM-3).

From the following analysis results, it was confirmed to be the target product.
Elemental analysis _{(C 42 H 40 N 18 O} 4 S 4 Ni)

The compound thus obtained exhibited an absorption maximum at 549.0 nm in a chloroform solution, and the gram extinction coefficient was 1.00 × 10 ⁵ ml / g. cm.

Synthesis of metal chelate compound (AM-54) In a mixed solution of 6.8 g of acetic acid and 4.0 g of propionic acid, 0.75 g of the compound represented by the following structural formula (4-b) was dissolved, and phosphorous was added at 0-5 ° C. 1.9 g of acid and 2.82 g of 40% nitrosylsulfuric acid were added dropwise. The mixture was stirred at the same temperature for 1 hour to diazotize. 2.38 g of the compound represented by the following structural formula (5-a), 0.31 g of urea and 3.00 g of sodium acetate were dissolved in 70 g of methanol, and the obtained diazo solution was charged dropwise at 0-5 ° C. The mixture was stirred at the same temperature for 2 hours and left overnight. The precipitated crystals were separated by filtration, washed with water and dried to obtain 2.00 g of a compound represented by the following structural formula (1-54).

  Next, 1.95 g of the compound represented by the formula (1-54) is dissolved in 80 g of methanol and 40 g of terahydrofuran, and 0.67 g of nickel acetate tetrahydrate is added at 50 to 55 ° C. Stir for hours. The precipitated crystals were separated by filtration, washed with water and dried to obtain 1.89 g of compound (AM-54).

From the following analysis results, it was confirmed to be the target product.
Elemental analysis _{(C 34 H 36 N 14 O} 6 S 4 Ni)

The compound thus obtained showed an absorption maximum at 550.0 nm in a chloroform solution, and the gram extinction coefficient was 0.92 × 10 ⁵ ml / g. cm.

Synthesis of metal chelate compound (AM-58) In a mixed solution of 4.0 g of acetic acid and 2.0 g of propionic acid, 0.71 g of the compound represented by the following structural formula (4-c) was dissolved, and 40 at 0-5 ° C. 2.18 g of% nitrosylsulfuric acid was added dropwise. The mixture was stirred at the same temperature for 1 hour to diazotize. 2.00 g of the compound represented by the following structural formula (5-a), 0.37 g of urea and 6.2 g of sodium acetate were dissolved in 50 g of methanol, and the obtained diazo solution was charged dropwise at 0-5 ° C. The mixture was stirred at the same temperature for 2 hours and left overnight. The reaction solution was discharged into 200 g of water, and the precipitated crystals were separated by filtration, washed with water and dried to obtain 2.68 g of a compound represented by the following structural formula (1-58).

  Next, a solution obtained by dissolving 2.42 g of the compound represented by the formula (1-58) in 80 g of methanol and 20 g of tetrahydrofuran, and dropwise adding a solution of 0.81 g of nickel acetate tetrahydrate in 8 g of methanol at 50 to 55 ° C. The mixture was stirred at the same temperature for 1 hour. The precipitated crystals were separated by filtration, washed with water, and dried to obtain 2.34 g of compound (AM-58).

From the following analysis results, it was confirmed to be the target product.
Elemental analysis _{(C 34 H 36 N 14 O} 6 S 4 Ni)

The compound thus obtained showed an absorption maximum at 557.0 nm in a chloroform solution, and the gram extinction coefficient was 0.90 × 10 ⁵ ml / g. cm.

  The metal chelate compound (AM-1) described in Table 2 is formed on an injection-molded polycarbonate substrate having a spiral groove (pitch = 0.74 um, depth = 165 nm, width = 0.33 um) having a thickness of 0.6 mm and a diameter of 120 mmΦ. Then, it was dissolved in tetrafluoropropanol (20 g / l), and a film was formed by spin coating so that the film thickness on the grooves was approximately 80 nm and the film thickness between the grooves was 20 nm. After drying at 80 ° C. for 2 hours, an AgPdCu reflective film is formed with a film thickness of 80 nm using a sputtering apparatus (CDI-900) manufactured by Balzers, and on this reflective layer, UV curable resin: SD17 (Dainippon Ink) After being coated and UV cured, a 0.6 mm thick polycarbonate substrate was laminated thereon as described above, and an optical recording medium was produced by bonding with UV light using a KZ8681 radical polymerization adhesive manufactured by JSR.

  Disc tester DDU1000 manufactured by Pulstec Industrial Co., Ltd .: wavelength = 661 nm, NA = 0.60, linear velocity = 3.5 m / s (DVD-R standard recording velocity), linear velocity = 14 m / second. Each DVDR-compatible EFM + signal was recorded at s (4 times the DVD-R standard recording speed) and linear velocity = 28 m / s (8 times the DVD-R standard recording speed). Recording conditions were recorded by adjusting the pulse conditions described in the DVD-R standard (ver. 2.0) at high speeds of 1 ×, 4 ×, and 8 ×, respectively, so as to be optimal for each pit. Jitter measurement was performed on these recording parts at a standard DVD speed. In the DVDR medium shown in this example, a wide power window was confirmed with a good jitter value at any of 1 × speed, 4 × speed, and 8 × speed.

  An optical recording medium was produced in the same manner as in Example 5 except that the metal chelate compound (AM-2) was dissolved in octafluoropentanol. Further, evaluation was performed in the same manner as in Example 5. As a result, a wide power window was confirmed with a good jitter value at any of 1 × speed, 4 × speed, and 8 × speed.

[Examples 7 to 25]
An optical recording medium was produced in the same manner as in Example 5 except that the metal chelate compounds described in Table 2 were used as appropriate.

  When these optical recording media were evaluated in the same manner as in Example 5, a wide power window could be confirmed with a good jitter value at any of 1 × speed, 4 × speed, and 8 × speed.

[Example 26]
An optical recording medium was produced in the same manner as in Example 5 except that a mixture of metal chelate compounds (AM-1) and (AM-21) (weight ratio 9: 1) was dissolved in tetrafluoropropanol. Further, evaluation was performed in the same manner as in Example 5. As a result, a wide power window was confirmed with a good jitter value at any of 1 × speed, 4 × speed, and 8 × speed.

[Examples 27 to 30]
An optical recording medium was produced in the same manner as in Example 26 except that a mixture of metal chelate compounds described in Table 2 was appropriately used.

  When these optical recording media were evaluated in the same manner as in Example 5, a wide power window could be confirmed with a good jitter value at any of 1 × speed, 4 × speed, and 8 × speed.

[Comparative Example 1]
Using the metal chelate compound of the following structural formula (7), an optical recording medium was produced in the same manner as in Example 5, and the same evaluation was performed. The jitter value of the signal characteristics exceeded 10% at any of the 1 × speed, 4 × speed, and 8 × speed, and good signal characteristics were not obtained.

[Comparative Example 2]
An optical recording medium was prepared in the same manner as in Example 5 using the metal chelate compound represented by the following structural formula (8), and the same evaluation was performed. Good signal characteristics were obtained at 1 × speed and 4 × speed, but recording sensitivity was poor, and good recording could not be performed at 8 × speed.

  Table 7 shows the measured 1 × speed, 4 × speed, and 8 × speed jitter and the degree of modulation in Examples 5 to 30 and Comparative Examples 1 and 2. In the DVDR medium shown in this example, a wide power window was confirmed with a good jitter value at any of 1 × speed, 4 × speed, and 8 × speed.

  By using the metal chelate compound of the present invention as a recording layer, recording / reproduction is possible with a laser having a wavelength of 520 to 690 nm, which is a high-density optical recording medium. A medium can be provided.

It is a cross-sectional structure diagram showing a conventional optical recording medium and a layer structure of the present invention.

Explanation of symbols

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

Claims (5)

A metal chelate compound formed from two or more azo compounds which may be the same or different from each other and a metal salt having two or more valences, and at least one of the azo compounds is represented by the following general formula (1) A metal chelate compound which is an azo compound represented by the formula:

(In the formula, rings A and X each independently represent a heterocyclic ring optionally having a substituent, and ring B represents an aromatic hydrocarbon ring.) In general formula (1), ring A may have a substituent, an imidazolyl group, an oxazoyl group, a thiazoyl group,
Pyrazoyl group, isoxazoyl group, isothiazoyl group,
2. The metal chelate compound according to claim 1, which is a triazoyl group, a thiadiazoyl group, an isothiadiazoyl group, or a pyridyl group. In the general formula (1), X may have an optionally substituted imidazolyl group, oxazoyl group, thiazoyl group,
Pyrazoyl group, isoxazoyl group, isothiazoyl group,
2. The metal chelate compound according to claim 1, which is a furyl group, a thienyl group, or a pyridyl group. A metal chelate compound formed from two azo compounds represented by the following general formula (2), which may be different from or identical to each other, and a metal salt of Ni, Co or Cu.

(Wherein Y ₁ , Y ₂ , Y ₃ , Y ₄ , Y ₅ , Y ₆ and Y ₇ are each independently a carbon atom, nitrogen atom, oxygen atom, sulfur atom, C—R ₄ , N—R ₄ . (R ₄ is a hydrogen atom, a halogen atom, a formyl group, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an amino group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or 2 carbon atoms. -7 acyl group, alkenyl group having 2 to 6 carbon atoms, hydroxyalkyl group having 1 to 6 carbon atoms, alkoxycarbonyl group having 2 to 7 carbon atoms, alkylamino group having 1 to 12 carbon atoms, 3 to 7 carbon atoms R ₁ , R _2, and R ₃ are each an alkoxycarbonylalkyl group, a C 1-6 alkylthio group, a C 1-6 alkylsulfonyl group, or a C 2-6 alkylcarbonylamino group. Germany Hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 16 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, _{R 1} and _{R 2} or _{R 3} R ₂ and R ₃ may be linked to form a 5- to 6-membered ring.)   An optical recording medium having at least a recording layer and a reflective layer on a substrate, wherein the recording layer contains at least one metal chelate compound according to any one of claims 1 to 4.

Images