JP2005305838A - Optical recording material and optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording medium, which has favorable sensitivity and, at the same time, excellent in jitter and light stability even at the speed-up of recording speed, and an optical recording material employing the same. <P>SOLUTION: This optical recording material is used for an optical recording medium, which can record information by being irradiated with light and includes a cation represented by general formula (1), wherein R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>, R<SP>4</SP>, R<SP>5</SP>and R<SP>6</SP>independently and respectively represent a 1-4C alkyl group or the like, R<SP>7</SP>represents a hydrogen atom or the like, Q<SP>1</SP>and Q<SP>2</SP>independently and respectively represent an atomic group comprising a benzen ring or the like provided that at least one among R<SP>1</SP>, R<SP>2</SP>R<SP>3</SP>and R<SP>4</SP>represents a group, which is not a methyl group, and a chelate compound of an azo compound and a metal under the condition that the containing percentage of the chelate compound is 10-70 mol% on the total amount of the cation and the chelate compound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical recording medium for recording information by light irradiation and an optical recording material used therefor.

As optical recording media, optical recording disks such as CD-R (recordable CD) and DVD-R (recordable DVD) have already been widely used. The wavelength of the reproduction light is being shortened. For example, the current recording / reproducing wavelength of CD-R is 780 nm, but the next-generation CD-R and DVD-R are shortened to 635-680 nm. As a dye used for an optical recording medium for dealing with such short-wavelength light, a dye using a cyanine dye has been known (for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-34499

  The optical recording medium is required to cope with an increase in recording speed in addition to the above-described shortening of the wavelength. In order to increase the speed, it is desirable to use a dye with higher sensitivity. However, as the sensitivity of the dye increases, the fluctuation of the reproduction signal in the time direction (jitter) increases and the light stability (light resistance) increases. There tends to be a decline. As the speed increases further in the future, it is becoming difficult for conventional dyes to maintain satisfactory levels of satisfactory sensitivity, jitter and light stability at the same time.

  The present invention has been made in view of the above circumstances, and provides an optical recording medium excellent in jitter and light stability even when the recording speed is increased while having good sensitivity, and an optical recording material used therefor The purpose is to do.

  In order to solve the above problems, an optical recording material of the present invention is an optical recording material used for an optical recording medium capable of recording information by light irradiation, and includes a cation represented by the following general formula (1): And an azo compound and a metal chelate compound, and the content of the chelate compound is 10 to 70 mol% based on the total amount of the cation and the chelate compound.

  The optical recording medium of the present invention is an optical recording medium capable of recording information by light irradiation, and comprises a cation represented by the following general formula (1) and a chelate compound of an azo compound and a metal. The content of the chelate compound is 10 to 70 mol% based on the total amount of the cation and the chelate compound.

［式中、Ｒ^１及びＲ^２はそれぞれ独立に炭素数１〜４のアルキル基若しくは置換基を有していてもよいベンジル基、又は互いに連結して３〜６員環を形成する基を示し、Ｒ^３及びＲ^４はそれぞれ独立に炭素数１〜４のアルキル基若しくは置換基を有していてもよいベンジル基、又は互いに連結して３〜６員環を形成する基を示し、Ｒ^５及びＲ^６はそれぞれ独立に炭素数１〜４のアルキル基又はアリール基を示し、Ｒ^７は水素原子、ハロゲン原子、シアノ基、置換基を有していてもよいアルキル基又は置換基を有していてもよいアリール基を示し、Ｑ^１及びＱ^２はそれぞれ独立に置換基を有していてもよいベンゼン環又は置換基を有していてもよいナフタレン環を構成する原子群を示す。但し、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４のうち少なくとも１個はメチル基でない基を示す。］

[Wherein, R ¹ and R ² each independently represent an alkyl group having 1 to 4 carbon atoms or a benzyl group which may have a substituent, or a group which is linked to each other to form a 3- to 6-membered ring. , R ³ and R ⁴ each independently represents an alkyl group having 1 to 4 carbon atoms or a benzyl group which may have a substituent, or a group which is linked to each other to form a 3- to 6-membered ring, and R ⁵ And R ⁶ each independently represents an alkyl group or aryl group having 1 to 4 carbon atoms, and R ⁷ has a hydrogen atom, a halogen atom, a cyano group, or an optionally substituted alkyl group or substituent. Q ¹ and Q ² each independently represents an atomic group constituting a benzene ring which may have a substituent or a naphthalene ring which may have a substituent. However, at least one of R ¹ , R ² , R ³ and R ⁴ represents a group that is not a methyl group. ]

  The optical recording material of the present invention and the optical recording layer provided in the optical recording medium of the present invention use a cation having the above specific structure as a dye, and further combine the chelate compound in the above specific ratio. As a result, even when the recording speed is increased, the jitter and light stability are excellent while having good sensitivity.

  Further, the optical recording material of the present invention is preferably obtained by mixing the salt composed of the cation and its counter anion and the chelate compound, and the optical recording layer provided in the optical recording medium of the present invention comprises It is preferable to contain a mixture obtained by mixing a salt composed of the cation and its counter anion and the chelate compound.

  Since such an optical recording material and an optical recording medium are obtained by simply mixing two or more kinds of materials, they can be manufactured more efficiently. The optical recording material and the optical recording medium obtained by such mixing contain the counter anion of the above cation, and may further contain the counter cation of the chelate compound. It tends to act as an impurity that impairs the stability of the quality of the recording material. However, the present inventors have found that such an adverse effect is unlikely to occur in the optical recording material and the optical recording medium of the present invention combined with the specific dye as described above.

  According to the present invention, an optical recording medium excellent in jitter and light stability and an optical recording material used therefor can be obtained even when recording speed is increased while having good sensitivity.

(Optical recording material)
The optical recording material of the present invention contains a cation represented by the general formula (1) (hereinafter sometimes referred to as “trimethine cyanine dye cation”) and a chelate compound of an azo compound and a metal. These cations and chelate compounds can each act as a dye for optical recording, but are used in combination in the present invention.

In the general formula ^(1), at least one of R ^1, R 2, ^{R 3} and ^{R 4} are preferably substituted is also good benzyl group. When these substituents are benzyl groups which may have a substituent, the effect of suppressing jitter can be obtained more remarkably.

R ⁷ may be a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, a cyano group, an optionally substituted phenyl group or an optionally substituted benzyl group. Among these, a hydrogen atom is particularly preferable.

  Specific examples of the trimethine cyanine dye cation represented by the general formula (1) include those shown in the following Tables 1 to 6, and these are used alone or in combination. These trimethine cyanine dye cations can be obtained by synthesis by a known method.

The optical recording material usually contains a counter anion that neutralizes the charge of these trimethine cyanine dye cations. Examples of the counter anion include monovalent anions such as ClO ₄ ⁻ , I ⁻ , BF ₄ ⁻ , PF ₆ ⁻ and SbF ₆ ⁻ . Alternatively, when the chelate compound is an anion, it may be used as a counter anion of the trimethine cyanine dye cation to form a salt. Among them, PF ₆ ^- and SbF ₆ ^- at least one of the anions of the preferred in view optimization of the leveling rate is easy.

Here, the leveling rate is “leveling rate C = [groove recording layer thickness D _G (μm) −land portion recording layer thickness D _I (μm)] / groove depth A (μm). ”. By optimizing the leveling rate, the balance between the reflectance and the modulation degree is good, and excellent jitter characteristics can be obtained. The leveling ratio C in DVD + R and DVD-R is preferably 0.1 to 0.4, and more preferably 0.2 to 0.3. When the leveling rate is less than 0.1, sufficient reflectance and modulation degree tend not to be obtained. Further, when the leveling ratio exceeds 0.4, the jitter tends to increase or the reflectance tends to decrease. Or SbF ₆ ^{- -} PF ₆ in the optical recording layer as an anion by containing, flowable in the state of the coating solution is improved. Therefore, the coverage of the recording layer ranging groove portion from the land portion is improved, it is possible to reduce the difference in thickness between D _G and D _I.

  The chelate compound is a metal chelate compound formed by coordination of an azo compound having an azo group substituted with an aromatic ring with a metal, and is also called an azo dye or an azo dye. As an azo compound which comprises this chelate compound, the compound represented by following General formula (2) is mentioned, for example.

In the general formula (2), Ar ¹ and Ar ² are groups each consisting of an aromatic ring which may be the same or different, and at least one of them is an aromatic ring having a substituent capable of coordinating to a metal atom, Alternatively, it is a nitrogen-containing heteroaromatic ring having a nitrogen atom that can coordinate to a metal atom. The substituent capable of coordinating to the metal atom and the nitrogen atom capable of coordinating to the metal atom are preferably in a position capable of coordinating to the metal together with the azo group (for example, ortho-position in the case of a benzene ring).

The aromatic ring constituting Ar ¹ and Ar ² may be a single ring, a condensed polycycle or a polycyclic ring assembly. Examples of such aromatic rings include benzene ring, naphthalene ring, pyridine ring, thiazole ring, benzothiazole ring, oxazole ring, benzoxazole ring, quinoline ring, imidazole ring, pyrazine ring, pyrrole ring, etc. Of these, a benzene ring, a pyridine ring, a quinoline ring and a thiazole ring are particularly preferable.

Examples of the substituent capable of coordinating to a metal atom include a group having active hydrogen. Examples of the group having active hydrogen include —OH, —SH, —NH ₂ , —COOH, —CONH ₂ , —SO ₂ NH ₂ , —SO ₃ H, —NHSO ₂ CF ₃ , and among these, -OH is particularly preferred.

Ar ¹ and Ar ² may have other substituents in addition to the above. Ar ¹ and Ar ² may have the same or different substituents. When Ar ¹ is different, Ar ¹ is a nitro group, a halogen atom (eg, a chlorine atom or a bromine atom), a carboxyl group, a sulfo group, or a sulfamoyl group And at least one group selected from the group consisting of an alkyl group (preferably having 1 to 4 carbon atoms, more preferably a methyl group), Ar ² being an amino group (a dialkylamino group having 2 to 8 carbon atoms in total) For example, a dimethylamino group, a diethylamino group, a methylethylamino group, a methylpropylamino group, a dibutylamino group, a hydroxyethylmethylamino group and the like, and an alkoxy group (preferably having 1 to 4 carbon atoms). For example, a methoxy group), an alkyl group (preferably having 1 to 4 carbon atoms, more preferably a methyl group), It preferably has at least one group selected from the group consisting of a vinyl group (preferably a monocyclic group such as a phenyl group and a chlorophenyl group), a carboxyl group and a sulfo group. In addition, when Ar < ¹ > is a benzene ring, it is preferable that the substituent exists in meta position or para position with respect to an azo group, and it is more preferable that it is in meta position.

As the metal (center metal) constituting the chelate compound, transition metals such as Co, Mn, Cr, Ti, V, Ni, Cu, Zn, Mo, W, Ru, Fe, Pd, Pt, and Al are preferable. Alternatively, V, Mo, and W, which is the oxide ions ^{respectively, VO 2+, VO 3+, MoO} 2+, MoO 3+, may have as ^{WO 3+} like. Among these, VO ²⁺ , VO ³⁺ , Co, Ni and Cu are particularly preferable.

  In the chelate compound, usually, an azo compound as described above is used as a bidentate or tridentate ligand, and a coordination bond is formed with a metal. In the case where the azo compound has a substituent having active hydrogen, the active hydrogen is usually eliminated to form a bidentate or tridentate ligand.

The chelate compound may be neutral as a whole, or may be an anion or a cation. When the chelate compound is an anion, it usually forms a salt with its counter cation. Examples of the counter cation include metal cations such as Na ⁺ , Li ⁺ , and K ⁺ , ammonium, and tetraalkylammonium. Alternatively, a salt may be formed using the trimethine cyanine dye cation as a counter cation.

  Specific examples of the chelate compound include A1 to A49 shown in Tables 7 to 12, and these are used alone or in combination. In the chelate compounds shown in Tables 7 to 12, two azo compounds are coordinated to one element of the central metal. In the table, two types of azo compound and central metal each indicate that they are contained at a molar ratio of 1: 1, and one in which the central metal is indicated by “V═O” is an azo compound. Is coordinated to acetylacetone vanadium. These chelate compounds can be obtained by synthesis according to known methods (see, for example, Furukawa, Anal. Chim. Acta., 140, p. 289, 1982).

  In the optical recording material of the present invention, the content of the chelate compound is 10 to 70 mol% based on the total amount of the cation and the chelate compound. The content is preferably 15 to 50 mol%, and more preferably 20 to 30 mol%. If this content is less than 10 mol%, the light stability tends to be insufficient, and if it exceeds 70 mol%, jitter tends to increase particularly in an optical recording medium on which high-speed recording has been performed.

  The optical recording material containing the cation and the chelate compound in such a ratio is a mixture in which the chelate compound is mixed with the salt composed of the cation and its counter anion, or when the chelate compound is an anion. It can be obtained by forming a salt (integrated salt) composed of a trimethine cyanine dye cation and a chelate compound anion. Alternatively, the mixture and the integral salt may coexist. In particular, it is preferable to prepare the above mixture to obtain an optical recording material because it is simple and efficient and has a high degree of freedom in selecting a dye.

  The optical recording material as described above can be suitably used for forming a recording layer of the optical recording medium of the present invention as described below.

(Optical recording medium)
FIG. 1 is a partial sectional view showing a preferred embodiment of an optical recording disk according to the optical recording medium of the present invention. The optical recording disk 1 shown in FIG. 1 has a laminated structure in which a recording layer 3, a reflective layer 4, a protective layer 5, an adhesive layer 7 and a substrate 6 are provided in close contact with each other on a substrate 2. The optical recording disk 1 is a write-once type optical recording disk and can be recorded and reproduced with light having a short wavelength of 630 to 685 nm.

  The substrates 2 and 6 are each disk-shaped having a diameter of about 64 to 200 mm and a thickness of about 0.6 mm, and recording and reproduction are performed from the back side (lower side in the figure) of the substrate 2. Therefore, it is preferable that at least the substrate 2 is substantially transparent to recording light and reproducing light, and more specifically, the transmittance of the substrate 2 with respect to recording light and reproducing light is preferably 88% or more. . As the material of the substrate 2, a resin or glass that satisfies the above-described conditions regarding transmittance is preferable, and among them, a thermoplastic resin such as a polycarbonate resin, an acrylic resin, an amorphous polyolefin, a TPX, and a polystyrene resin is particularly preferable. On the other hand, the material of the substrate 6 is not particularly limited, but for example, the same material as that of the substrate 2 can be used.

  A tracking groove 23 is formed as a concave portion on the recording layer 3 forming surface of the substrate 2. The groove 23 is preferably a spiral continuous groove, and preferably has a depth of 80 to 250 nm, a width of 200 to 500 nm, and a groove pitch of 600 to 1000 nm. By configuring the groove in this way, a good tracking signal can be obtained without reducing the reflection level of the groove. The groove 23 can be formed at the same time when the substrate 2 is formed by injection molding or the like using the above resin. However, after the substrate 2 is manufactured, a resin layer having the groove 23 is formed by the 2P method or the like. A composite substrate with a resin layer may be used.

  The recording layer 3 is formed using the optical recording material of the present invention. The recording layer 3 can be formed by applying a mixed solution obtained by dissolving or dispersing the optical recording material of the present invention in a solvent onto the substrate 2 and removing the solvent from the coating film. As the solvent of the mixed solution, alcohol solvents (including alkoxy alcohol systems such as keto alcohol systems and ethylene glycol monoalkyl ether systems), aliphatic hydrocarbon solvents, ketone solvents, ester solvents, ether solvents, Aromatic solvents, alkyl halide solvents and the like can be mentioned. Among them, alcohol solvents and aliphatic hydrocarbon solvents are preferable.

  As the alcohol solvent, an alkoxy alcohol system, a keto alcohol system, or the like is preferable. In the alkoxy alcohol solvent, the alkoxy moiety preferably has 1 to 4 carbon atoms, the alcohol moiety preferably has 1 to 5 carbon atoms, more preferably 2 to 5 carbon atoms, and the total number of carbon atoms. It is preferable that it is 3-7. Specifically, ethylene glycol monoalkyl ether (cellosolve) such as ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (also referred to as ethyl cellosolve, ethoxyethanol), butyl cellosolve, 2-isopropoxy-1-ethanol, etc. And 1-methoxy-2-propanol, 1-methoxy-2-butanol, 3-methoxy-1-butanol, 4-methoxy-1-butanol, 1-ethoxy-2-propanol and the like. Examples of keto alcohols include diacetone alcohol. Furthermore, fluorinated alcohols such as 2,2,3,3-tetrafluoropropanol can also be used.

  As the aliphatic hydrocarbon solvent, n-hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane, dimethylcyclohexane, n-octane, iso-propylcyclohexane, t-butylcyclohexane and the like are preferable. Cyclohexane and the like are preferable.

  Examples of the ketone solvent include cyclohexanone.

  In the present invention, an alkoxy alcohol system such as an ethylene glycol monoalkyl ether system is particularly preferable, and ethylene glycol monoethyl ether, 1-methoxy-2-propanol, 1-methoxy-2-butanol and the like are particularly preferable. A solvent may be used individually by 1 type, or 2 or more types of mixed solvents may be sufficient as it. For example, a mixed solvent of ethylene glycol monoethyl ether and 1-methoxy-2-butanol is preferably used.

  The mixed solution may contain a binder, a dispersant, a stabilizer and the like as appropriate in addition to the above components.

  Examples of the application method of the mixed solution include a spin coating method, a gravure application method, a spray coating method, and a dip coating method, and among these, the spin coating method is preferable.

  The thickness of the recording layer 3 thus formed is preferably 50 to 200 nm. In particular, the thickness of 70 to 150 nm is more preferable because the balance between the degree of modulation and the reflectance is improved. Outside this range, the reflectivity tends to be low, making reproduction difficult. Further, when the thickness of the recording layer 3 in the portion adjacent to the groove 23 is 200 nm or more, the balance between the modulation degree and the reflectance tends to deteriorate.

  The extinction coefficient (imaginary part k of the complex refractive index) of the recording layer 3 with respect to the recording light and the reproduction light is preferably 0 to 0.20. When the extinction coefficient exceeds 0.20, sufficient reflectance tends not to be obtained. The refractive index of the recording layer 3 (real part n of the complex refractive index) is preferably 1.8 or more. When the refractive index is less than 1.8, the degree of signal modulation tends to be small. The upper limit of the refractive index is not particularly limited, but is usually about 2.6 for the convenience of organic dye synthesis.

  The extinction coefficient and refractive index of the recording layer 3 can be obtained according to the following procedure. First, a measurement sample is prepared by providing a recording layer on a predetermined transparent substrate at about 40 to 100 nm, and then the reflectance of the measurement sample through the substrate or the reflectance from the recording layer side is measured. Desired. In this case, the reflectance is measured by specular reflection (about 5 °) using the wavelength of the recording / reproducing light. Further, the transmittance of the sample is measured. From these measured values, the extinction coefficient and the refractive index can be calculated according to the method described in, for example, Kyoritsu Zensho “Optics”, Kozo Ishiguro, pages 168 to 178.

  On the recording layer 3, the reflective layer 4 is provided in close contact with the recording layer 3. The reflective layer 4 can be formed by performing vapor deposition, sputtering, or the like using a highly reflective metal or alloy. Examples of the metal and alloy include gold (Au), copper (Cu), aluminum (Al), silver (Ag), and AgCu. The thickness of the reflective layer 4 thus formed is preferably 10 to 300 nm.

  On the reflective layer 4, a protective layer 5 is provided in close contact with the reflective layer 4. The protective layer 5 may be a layer or a sheet. For example, the protective layer 5 is formed by applying a coating liquid containing a material such as an ultraviolet curable resin on the reflective layer 4 and drying the coating film as necessary. Is possible. In the application, a spin coating method, a gravure coating method, a spray coating method, a dip coating method, or the like can be applied. The thickness of the protective layer 5 thus formed is preferably 0.5 to 100 μm.

  Furthermore, the substrate 6 is provided on the protective layer 5 via the protective layer 5 and the adhesive layer 7. The substrate 6 can be made of the same material and thickness as the substrate 2.

  When recording or additional recording is performed on the optical recording disk 1 having the above-described configuration, recording light having a predetermined wavelength is irradiated in a pulse form from the back surface of the substrate 2 to change the light reflectance of the irradiation section. At this time, according to the optical recording disk 1 provided with the recording layer 3 containing the cation and the chelate compound as dyes, information is recorded / reproduced at a high speed by a short wavelength recording / reproducing light. However, sensitivity, jitter, and light stability can be achieved at a high level in a well-balanced manner.

  In the above embodiment, an optical recording disk having one recording layer 3 as a recording layer has been described. However, a plurality of recording layers may be provided, and each layer may contain a different dye. Thereby, information can be recorded / reproduced by a plurality of recording / reproducing lights having the same or different wavelengths. In this case, a translucent reflective film that is translucent to recording / reproducing light of each wavelength may be provided on the surface of each recording layer opposite to the light incident surface.

  The optical recording disk 1 obtained in this way is composed of two optical recording disks 1 or a single optical recording disk 1 and another optical recording disk having a different layer structure. It can also be used by attaching the light incident surface (substrate 2 side) outside.

  FIG. 2 is a partial cross-sectional view showing a preferred embodiment of the optical recording disk according to the above-described bonding mode. The optical recording disc 10 shown in FIG. The reflective layer 14, the protective layer 15, the adhesive layer 50, the protective layer 25, the reflective layer 24, the recording layer 23, and the substrate 22 are stacked in this order. That is, the optical recording disk 10 has a configuration in which two optical recording disks having the same configuration as the optical recording disk 1 shown in FIG. 1 are bonded so that the respective protective layers face each other with the adhesive layer 50 interposed therebetween. It is what has. This optical recording disk 10 is a write-once digital video disk corresponding to the DVD standard, and performs recording / reproduction with light having a short wavelength of 650 to 670 nm.

  The adhesive layer 50 is formed by a hot melt adhesive, an ultraviolet curable adhesive, a heat curable adhesive, an adhesive adhesive, or the like, for example, a roll coater method, a screen printing method, a spin coating method, or the like. It can be formed by a coating method or the like. In the case of DVD-R, it is preferable to form the adhesive layer 50 by a screen printing method or a spin coating method using an ultraviolet curable adhesive from the viewpoint of balance of workability, productivity, disk characteristics and the like. The thickness of the adhesive layer 50 is preferably about 10 to 200 μm.

  The substrates 12 and 22, the recording layers 13 and 23, the reflective layers 14 and 24, and the protective layers 15 and 25 are formed by the same material and method as those of the optical recording disk 1 shown in FIG. The thickness of each of the substrates 12 and 22 is preferably about 0.6 mm. Grooves 123 and 223 are formed on the recording layer 13 forming surface of the substrate 12 and the recording layer 23 forming surface of the substrate 22, respectively. The grooves 123 and 223 preferably have a depth of 60 to 200 nm, a width of 200 to 500 nm, and a groove pitch of 600 to 1000 nm. Further, the thickness of each of the recording layers 13 and 23 is preferably 50 to 300 nm, and the complex refractive index with respect to the light of 650 nm is n = 1.8 to 2.6 and k = 0.00 to 0.10. Preferably there is.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

(Example 1)
A trimethine cyanine dye comprising a trimethine cyanine dye cation and its counter anion on a polycarbonate resin substrate having a pregroove (depth 0.16 μm, width 0.30 μm, groove pitch 0.74 μm) formed on one surface; The optical recording material prepared by mixing the chelate compound with the combinations and ratios shown in Table 13 was dissolved in 2,2,3,3-tetrafluoropropanol so that the content was 1.0% by weight. The mixed liquid was applied and dried to form a recording layer (thickness 130 nm). Next, an Ag reflection layer (thickness 85 nm) is formed on the recording layer by sputtering, and a transparent protective layer (thickness 5 μm) made of an ultraviolet curable acrylic resin is further formed on the Ag reflection layer. Thus, a laminated structure was obtained. Further, the two laminated structures were bonded with an adhesive so that the respective protective layers were on the inner side, thereby producing an optical recording disk having the same configuration as the optical recording disk 10 shown in FIG. The counter anion of the trimethine cyanine dye was PF ₆ ⁻ and the counter cation of the chelate compound was Na ⁺ .

  A signal is recorded on the obtained optical recording disk at a linear speed of 3.5 m / s (corresponding to the same speed) or 28.0 m / s (corresponding to 8 times the speed) using a laser beam having a wavelength of 655 nm, and then the wavelength. Jitter was measured when reproduction was performed at a linear velocity of 3.5 m / s using 650 nm laser light. At this time, the lens aperture NA was set to 0.60. Furthermore, the obtained optical disk was irradiated (light exposure) for 40 hours with an 80,000-lux xenon lamp (xenon fade meter manufactured by Shimadzu Corporation), and jitter was also applied to the optical recording disk after irradiation in the same manner as described above. The light stability was measured and evaluated. The evaluation results are shown in Table 13.

(Examples 2 to 22 and Comparative Examples 1 to 7)
An optical recording disk was prepared and evaluated in the same manner as in Example 1 except that the optical recording materials were mixed in the combinations and ratios shown in Table 13, respectively. The trimethine cyanine dye cation and chelate compound No. 1 used in the optical recording material were used. No. shown in Table 1 to Table 6 and Table 7 to Table 12, respectively. The counter anion of the trimethine cyanine dye was PF ₆ ⁻ and the counter cation of the chelate compound was Na ⁺ . However, for those marked with “* 1” or “* 2” in Table 14, an optical recording material was prepared using a salt (integrated salt) of a trimethine cyanine dye cation and a chelate compound as described below. . In Comparative Examples 5, 6 and 7, R ¹ , R ² , R ³ and R ^{4 in the} general formula (2) as trimethine cyanine dye cations are all methyl groups, and the following chemical formula (3) And Comparative compounds A and B represented by (4) and (4), respectively. The evaluation results are summarized in Table 13 and Table 14.

In Examples 19 to 22 and Comparative Examples 6 to 7, optical recording materials were prepared using a salt (molar ratio 1: 1) of a trimethine cyanine dye cation and an anion of a chelate compound. For example, in the case of Example 20, the salt of trimethine cyanine dye cation T26 and chelate compound A3 is 50 mol% (that is, A3 is 25 mol%), and the salt of trimethine cyanine dye cation T26 and PF ₆ ⁻ is 50 mol%. An optical recording material was prepared by mixing at a mol% ratio (100 mol% in total), and an optical recording disk was produced and evaluated.

  As shown in Tables 13 and 14, according to Examples 1-22, it can be seen that, compared with Comparative Examples 1-7, jitter is kept low even when high-speed recording is performed, and light stability is excellent. It was. Therefore, according to the present invention, it was confirmed that an optical recording material and an optical recording medium having good sensitivity and excellent jitter and light stability can be obtained.

FIG. 1 is a partial sectional view showing an embodiment of an optical recording disk according to the optical recording medium of the present invention. FIG. 2 is a partial sectional view showing an embodiment of an optical recording disk according to the optical recording medium of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,10 ... Optical recording disc, 2, 6, 12, 22 ... Substrate, 3, 13, 23 ... Recording layer, 4, 14, 24 ... Reflective layer, 5, 15, 25 ... Protective layer, 23, 123, 223 ... groove, 7, 50 ... adhesive layer.

Claims (4)

An optical recording material used for an optical recording medium capable of recording information by light irradiation,
A cation represented by the following general formula (1);
A chelate compound of an azo compound and a metal,
The optical recording material whose content rate of the said chelate compound is 10-70 mol% on the basis of the total amount of the said cation and the said chelate compound.

[Wherein, R ¹ and R ² each independently represent an alkyl group having 1 to 4 carbon atoms or a benzyl group which may have a substituent, or a group which is linked to each other to form a 3- to 6-membered ring. , R ³ and R ⁴ each independently represents an alkyl group having 1 to 4 carbon atoms or a benzyl group which may have a substituent, or a group which is linked to each other to form a 3- to 6-membered ring, and R ⁵ And R ⁶ each independently represents an alkyl group or aryl group having 1 to 4 carbon atoms, and R ⁷ has a hydrogen atom, a halogen atom, a cyano group, or an optionally substituted alkyl group or substituent. Q ¹ and Q ² each independently represents an atomic group constituting a benzene ring which may have a substituent or a naphthalene ring which may have a substituent. However, at least one of R ¹ , R ² , R ³ and R ⁴ represents a group that is not a methyl group. ]   The optical recording material according to claim 1, obtained by mixing a salt composed of the cation and its counter anion and the chelate compound. An optical recording medium capable of recording information by light irradiation,
A cation represented by the following general formula (1);
A recording layer containing an azo compound and a metal chelate compound,
The optical recording medium whose content rate of the said chelate compound is 10-70 mol% on the basis of the total amount of the said cation and the said chelate compound.

[Wherein, R ¹ and R ² each independently represent an alkyl group having 1 to 4 carbon atoms or a benzyl group which may have a substituent, or a group which is linked to each other to form a 3- to 6-membered ring. , R ³ and R ⁴ each independently represents an alkyl group having 1 to 4 carbon atoms or a benzyl group which may have a substituent, or a group which is linked to each other to form a 3- to 6-membered ring, and R ⁵ And R ⁶ each independently represents an alkyl group or aryl group having 1 to 4 carbon atoms, and R ⁷ has a hydrogen atom, a halogen atom, a cyano group, or an optionally substituted alkyl group or substituent. Q ¹ and Q ² each independently represents an atomic group constituting a benzene ring which may have a substituent or a naphthalene ring which may have a substituent. However, at least one of R ¹ , R ² , R ³ and R ⁴ represents a group that is not a methyl group. ]   The optical recording medium according to claim 3, wherein the recording layer contains a mixture obtained by mixing the salt composed of the cation and its counter anion and the chelate compound.

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