JP2005305840A - Optical recording material and optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording material, which realize enough high sensitivity without being accompanied by so much increase of jitter for higher recording speed, and an optical recording medium. <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 (1), a chelate compound of an azo compound and a metal and a compound represented by general formula (2), wherein R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>, R<SP>4</SP>, R<SP>5</SP>, R<SP>6</SP>and R<SP>7</SP>independently and respectively represent alkyl group or the like, Q<SP>1</SP>and Q<SP>2</SP>independently and respectively represent an atomic group comprising a benzen ring, A represents a nitrogen atom or the like, X represents a hydrogen atom or the like, n represents 0 or 1 under the condition that a plurality of X in the same molecule may be equal to or different from one another and at least one of them represents the alkyl group or the like. <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 light of such a short wavelength, a dye made of a chelate compound of an azo compound and a metal (also referred to as “metal-containing azo dye”) is known ( For example, Patent Document 1).
JP-A-9-323478

  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, fluctuation in the time direction (jitter) of the reproduction signal tends to increase. As the speed increases in the future, it is becoming difficult for conventional dyes to maintain sufficiently satisfactory levels of sensitivity and jitter at the same time.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical recording medium that achieves sufficiently high sensitivity without a large increase in jitter and an optical recording material used therefor.

  In order to solve the above problems, an optical recording medium 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): It contains a chelate compound of an azo compound and a metal, and a compound represented by the following general formula (2).

  The optical recording medium of the present invention includes a recording layer containing a cation represented by the following general formula (1), a chelate compound of an azo compound and a metal, and a compound represented by the following general formula (2). It is characterized by providing.

[Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represents an alkyl group which may have a substituent or an aryl group which may have a substituent. , R ⁷ represents a hydrogen atom, a halogen atom, a cyano group, an optionally substituted alkyl group or an optionally substituted aryl group, and Q ¹ and Q ² are each independently a substituent. And A represents a nitrogen atom or a phosphorus atom, X represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. And n represents 0 or 1. However, R ¹ and R ² , and R ³ and R ⁴ may be groups that are connected to each other to form a cyclic structure, and at least one of R ¹ , R ² , R ^3, and R ⁴ is A group that is not a methyl group, and a plurality of Xs in the same molecule may be the same or different, and at least one of the plurality of Xs in the same molecule may have a substituent. The aryl group which may have is shown. ]

  The optical recording material of the present invention and the optical recording layer provided in the optical recording medium of the present invention contain the above cation as a dye and a chelate compound of an azo compound and a metal, and further contain the above specific compound. By combining, it has sufficient sensitivity and jitter is sufficiently suppressed. In particular, even at a high recording speed that has been difficult to put into practical use in the past, the sensitivity and jitter can be achieved at a sufficiently satisfactory level.

  Conventionally, if the recording layer of the optical recording medium contains the compound represented by the general formula (2), the recording layer tends to cause a decrease in sensitivity and a deterioration of the material adjacent to the recording layer. It was thought that it was rather preferable not to include a compound. However, in the system containing the specific cation as a dye as described above, the present inventors have shown that the dye sensitivity is remarkably improved and the jitter is sufficiently suppressed by containing the compound. I found it. The mechanism by which such an effect is manifested is not necessarily clear, but it is presumed that the compound promoted thermal decomposition of the dye by some action, and as a result, the sensitivity was enhanced without a significant increase in jitter.

  The total number of carbon atoms of the compound represented by the general formula (2) is preferably 20 or less. In other words, the total number of carbon atoms of each X in the same molecule is preferably 20 or less. When this total carbon number exceeds 20, when these compounds are blended at the same molar ratio, the concentration of the dye in the optical recording material or the recording layer is reduced as compared with the case where the layer carbon number is 20 or less. In addition, sufficient sensitivity tends to be difficult to obtain.

  In the compound represented by the general formula (2), X is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and 3 or 4 of a plurality of X in the same molecule has 1 carbon atom. More preferably, it is an alkyl group of ˜4.

In the cation, R ¹ and R ² are each independently a benzyl group which may have an alkyl group having 1 to 4 carbon atoms or a substituent, or a group which is linked to each other to form a 3- to 6-membered ring. Each of R ³ and R ⁴ is independently a benzyl group optionally having an alkyl group having 1 to 4 carbon atoms or a substituent, or a group that is linked to each other to form a 3- to 6-membered ring; ⁵ and R ⁶ are each independently an alkyl group or aryl group having 1 to 4 carbon atoms, and R ⁷ has a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, a cyano group, or a substituent. A phenyl group which may have a substituent or a benzyl group which may have a substituent, and Q ¹ and Q ² each independently have a benzene ring which may have a substituent or a naphthalene which may have a substituent Must be a group of atoms constituting a ring Preferred. A cation having such a specific structure is preferable because it has high sensitivity itself and is synergistically enhanced by the combination with the compound represented by the general formula (2).

The optical recording material of the present invention, and an optical recording layer of an optical recording medium comprising the present invention, in addition to the above components, PF ₆ ^- as the anion or SbF ₆ ^- to contain, is easy to optimize the leveling rate In some respects, it is preferable. In the optical recording material and the optical recording layer, at least a part of these anions usually forms a salt as a counter anion of the cation.

  According to the present invention, it is possible to obtain an optical recording medium and an optical recording material used therefor that achieve sufficiently high sensitivity without a large increase in jitter.

(Optical recording material)
The optical recording material of the present invention comprises a cation represented by the general formula (1) (hereinafter sometimes referred to as “trimethine cyanine dye cation”), a chelate compound of an azo compound and a metal, and the above general formula. And a compound represented by (2). The cation represented by the general formula (1) belongs to a cation of a dye, also called a trimethine cyanine dye.

In the trimethine cyanine dye cation, R ¹ and R ² are each independently an alkyl group having 1 to 4 carbon atoms or a benzyl group optionally having a substituent, or linked to each other to form a 3- to 6-membered ring. R ³ and R ⁴ are each independently a benzyl group optionally having an alkyl group having 1 to 4 carbon atoms or a substituent, or linked to each other to form a 3- to 6-membered ring. R ⁵ and R ⁶ are preferably each independently an alkyl group having 1 to 4 carbon atoms or an aryl group, and R ⁷ is a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. , A cyano group, a phenyl group which may have a substituent, or a benzyl group which may have a substituent, and Q ¹ and Q ² may each independently have a substituent. Good ben It is preferable to have a down ring or substituent is an atomic group constituting also good naphthalene ring. In particular, at least one of R ¹ , R ² , R ^3, and R ⁴ is preferably a benzyl group which may have a substituent, from the viewpoint that sensitivity is more remarkably enhanced. R ⁷ is more preferably a hydrogen atom.

  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 of the present invention usually contains a counter anion that neutralizes the charge of the trimethine cyanine dye cation as described above. Examples of the counter anion include monovalent anions such as ClO ₄ ⁻ , I ⁻ , BF ₄ ⁻ , PF ₆ ⁻ and SbF ₆ ⁻ . 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 optical recording material of the present invention contains at least one compound represented by the general formula (2) (hereinafter sometimes referred to as “addition compound”). The total number of carbon atoms of these additive compounds is preferably 20 or less. When this total carbon number exceeds 20, when these additive compounds are blended at the same molar ratio, the concentration of the dye in the optical recording material is reduced as compared with the case where the total carbon number is 20 or less. It tends to be difficult to obtain sufficient sensitivity.

  Further, in this additive compound, X is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and 3 or 4 of the plurality of X in the same molecule are alkyl groups having 1 to 4 carbon atoms. It is more preferable from the viewpoint of sensitivity and the like.

  The content ratio of the additive compound is preferably 0.5 to 50 mol% based on the total amount of the cation and the additive compound. When this content is less than 0.5 mol%, the sensitivity tends to decrease. When it exceeds 50 mol%, other adjacent materials in the optical recording medium such as a reflective layer made of silver are deteriorated. It tends to be promoted.

  Examples of the additive compound include an amine compound represented by the following general formula (3), an ammonium compound represented by the following general formula (4) or (5), and a phosphonium represented by the following general formula (6). Compounds, and these can be suitably used alone or in combination. However, in the following formulas (3), (4), (5) and (6), X represents an alkyl group which may have a substituent or an aryl group which may have a substituent.

一般式（３）で表されるアミン化合物はそのまま光記録材料を構成する他の成分と混合することができる。一方、一般式（４）又は（５）で表されるアンモニウム化合物や、一般式（６）で表されるホスホニウム化合物は、通常、その対アニオンとの塩を形成した状態で光記録材料を構成する他の成分と混合される。この対アニオンとしては、例えば、アゾ化合物と金属とのキレート化合物からなるアニオンが挙げられる。このキレート化合物については詳細に後述するが、これを光記録材料に含有させることによって、感度の著しい低下をともなうことなく光安定性（耐光性）を改善することができる。

The amine compound represented by the general formula (3) can be directly mixed with other components constituting the optical recording material. On the other hand, the ammonium compound represented by the general formula (4) or (5) and the phosphonium compound represented by the general formula (6) usually constitute an optical recording material in a state of forming a salt with the counter anion. To be mixed with other ingredients. Examples of the counter anion include an anion made of a chelate compound of an azo compound and a metal. The chelate compound will be described in detail later, but by incorporating it into the optical recording material, the light stability (light resistance) can be improved without significantly reducing the sensitivity.

  More specifically, examples of the additive compound include No. 1 shown in Table 7. Nos. 301 to 306, Nos. 401 to 406 and Table 9 Nos. 501 to 518 and Nos. Examples include phosphonium compounds of 601 to 612. Among these, No. in Table 7-10. Is preferably at least one selected from the group consisting of compounds represented by the chemical formulas of 301 to 305, 401 to 403, 501 to 503, and 601 to 602.

  The optical recording material of the present invention contains a chelate compound of an azo compound and a metal in addition to the above components. This chelate compound is a metal chelate compound formed by coordination of an azo compound having an azo group substituted with an optionally substituted aryl group with a metal, such as an azo dye or an azo dye. It is also called. As an azo compound which comprises this chelate compound, the compound represented by following General formula (7) is mentioned, for example.

In the general formula (7), Ar ¹ and Ar ² are groups consisting of aromatic rings 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. A position capable of coordinating to a metal atom and a nitrogen atom capable of coordinating to a metal atom, such as a position adjacent to the position substituted with the azo group, can be coordinated to the metal together with the azo group (for example, In the case of a benzene ring, it is preferably in the ortho position).

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 which it has 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 constituting the chelate compound (center metal), transition metals such as Co, Mn, 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 is usually mixed with other materials in the optical recording material in a salt state with its counter cation. As the counter ^cation, Na ^+, Li +, and metal cations ^{K +,} etc., additives compounds n is 1 in the general formula (2). Alternatively, a salt formed using the trimethine cyanine dye cation as a counter cation may be used.

  Specific examples of the chelate compound include A1 to A49 shown in Tables 11 to 16, and these are used alone or in combination. In the chelate compounds shown in Tables 11 to 16, two azo compounds are coordinated to one central metal element. 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 preferably 10 to 70 mol%, more preferably 15 to 50 mol%, based on the total amount of the cation and the chelate compound. It is still more preferable that it is 20-30 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 high-speed recording.

  When the optical recording material containing the cation and the chelate compound at such a ratio is mixed with the salt composed of the cation and its counter anion to form a mixture, or the chelate compound is an anion Can be obtained by forming a salt (integrated salt) comprising the cation and the 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, 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 and the like are 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, 2,2,
Fluorinated alcohols such as 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 in the form of a layer or a sheet. For example, a coating solution containing a material such as an ultraviolet curable resin is applied to the reflective layer 4.
It can be formed by applying on top and drying the coating as necessary. 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, a substrate 6 is provided on the protective layer 5 via an adhesive layer 7 on the protective layer 5. 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 additive compound, even when information is recorded / reproduced at a high speed by a recording / reproducing light having a short wavelength, Recording / reproduction characteristics (sensitivity and jitter) 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 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 bonding the light incident surface (substrate 5 side) outside.

  FIG. 2 is a partial cross-sectional view showing another 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 structure 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.

  For the adhesive layer 50, a hot melt adhesive, an ultraviolet curable adhesive, a heat curable adhesive, a pressure sensitive adhesive, or the like is used. 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)
One surface pregroove on (depth 0.16 [mu] m, width 0.30 .mu.m, groove pitch 0.74 [mu] m) in the polycarbonate resin substrate formed, trimethine cyanine dye cation and PF ₆ ^- tri cyanine dye and consisting An optical recording material prepared by mixing the additives in a combination shown in Table 17 at a ratio where the content ratio of the additive compound is 10% by weight based on the entire optical recording material is 1.0% by weight. Then, a mixed solution dissolved in 2,2,3,3-tetrafluoropropanol 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. In Table 17, No. of trimethine cyanine dye cation, additive compound and chelate compound. No. shown in Table 1 to Table 6, Table 7 to Table 10, and Table 11 to Table 16, respectively. And its chemical structure. Further, the chelate compound formed a salt with Na ⁺ or a cation of the additive compound, and an optical recording material was prepared using this salt.

A signal was recorded on the obtained optical recording disk at a linear velocity of 28.0 m / s (corresponding to 8 × speed) using a laser beam having a wavelength of 655 nm, and then a linear velocity of 3.5 m was obtained using a laser beam having a wavelength of 650 nm. / s when reproduced by an optimum recording power P ₀ as an indicator of the sensitivity of the dye was measured and jitter. At this time, the lens aperture NA was set to 0.60. The evaluation results are shown in Table 13.

(Examples 2-13 and Comparative Examples 1-2)
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 17, respectively. The evaluation results are summarized in Table 17. In Examples 4 and 5, a salt of a chelate compound and Na ⁺ is mixed with other materials, and in Examples 6 to 13, a salt of a chelate compound and an ammonium compound or phosphonium compound as an additive is mixed with other materials. Each optical recording material was prepared by mixing with the material. Further, in Comparative Example 2, the trimethine cyanine dye cation is represented by the following chemical formula (8), in which R ¹ , R ² , R ³ and R ^{4 in the} general formula (1) are all methyl groups. Comparative compounds were used.

As shown in Table 17, according to Examples 1 to 13, as compared with Comparative Examples 1-2, exhibit good sensitivity without significant increase in jitter (P ₀ is small) it was found. Therefore, according to the present invention, it was confirmed that an optical recording material and an optical recording medium that achieve sufficiently high sensitivity without a large increase in jitter 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 another embodiment of the 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 (10)

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,
An optical recording material containing a compound represented by the following general formula (2).

[Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represents an alkyl group which may have a substituent or an aryl group which may have a substituent. , R ⁷ represents a hydrogen atom, a halogen atom, a cyano group, an optionally substituted alkyl group or an optionally substituted aryl group, and Q ¹ and Q ² are each independently a substituent. And A represents a nitrogen atom or a phosphorus atom, X represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. And n represents 0 or 1. However, R ¹ and R ² , and R ³ and R ⁴ may be groups that are connected to each other to form a cyclic structure, and at least one of R ¹ , R ² , R ^3, and R ⁴ is A group that is not a methyl group, and a plurality of Xs in the same molecule may be the same or different, and at least one of the plurality of Xs in the same molecule may have a substituent. The aryl group which may have is shown. ]   The optical recording material according to claim 1, wherein the total carbon number of the compound is 20 or less.   The X is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and 3 or 4 of the plurality of X in the same molecule is an alkyl group having 1 to 4 carbon atoms. 2. The optical recording material according to 2. R ¹ and R ² are each independently an alkyl group having 1 to 4 carbon atoms or a benzyl group optionally having a substituent, or a group that is linked to each other to form a 3- to 6-membered ring, R ³ and R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms or a benzyl group optionally having a substituent, or a group that is linked to each other to form a 3- to 6-membered ring; ⁵ and R ⁶ are each independently an alkyl group or aryl group having 1 to 4 carbon atoms, and R ⁷ has a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, a cyano group, or a substituent. A phenyl group which may have a substituent or a benzyl group which may have a substituent, and Q ¹ and Q ² each independently have a benzene ring or a substituent which may have a substituent. Atoms constituting the naphthalene ring In it, the optical recording material according to any one of claims 1 to 3. PF ₆ ^- or SbF ₆ ^- containing optical recording material according to claim 1. 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,
An optical recording medium comprising a recording layer containing a compound represented by the following general formula (2).

[Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represents an alkyl group which may have a substituent or an aryl group which may have a substituent. , R ⁷ represents a hydrogen atom, a halogen atom, a cyano group, an optionally substituted alkyl group or an optionally substituted aryl group, and Q ¹ and Q ² are each independently a substituent. And A represents a nitrogen atom or a phosphorus atom, X represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. And n represents 0 or 1. However, R ¹ and R ² , and R ³ and R ⁴ may be groups that are connected to each other to form a cyclic structure, and at least one of R ¹ , R ² , R ^3, and R ⁴ is A group that is not a methyl group, and a plurality of Xs in the same molecule may be the same or different, and at least one of the plurality of Xs in the same molecule may have a substituent. The aryl group which may have is shown. ]   The optical recording medium according to claim 6, wherein the total carbon number of the compound is 20 or less.   The X is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and 3 or 4 of the plurality of X in the same molecule is an alkyl group having 1 to 4 carbon atoms. 8. The optical recording medium according to 7. R ¹ and R ² are each independently an alkyl group having 1 to 4 carbon atoms or a benzyl group optionally having a substituent, or a group that is linked to each other to form a 3- to 6-membered ring, R ³ and R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms or a benzyl group optionally having a substituent, or a group that is linked to each other to form a 3- to 6-membered ring; ⁵ and R ⁶ are each independently an alkyl group or aryl group having 1 to 4 carbon atoms, and R ⁷ has a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, a cyano group, or a substituent. A phenyl group which may have a substituent or a benzyl group which may have a substituent, and Q ¹ and Q ² each independently have a benzene ring or a substituent which may have a substituent. Atoms constituting the naphthalene ring In it, the optical recording medium according to any one of claims 6-8. The optical recording medium according to claim ₆ , wherein the recording layer contains PF ₆ ^— or SbF ₆ ^— .

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