JP2005187589A - Azo metal chelate dye and optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dye having a long absorption wavelength, and which is suitably used for a recording layer in an optical recording medium for high-speed recording. <P>SOLUTION: The azo metal chelate dye, which comprises an azo compound represented by formula (1) and a metal atom, has a longer absorption wavelength than conventional azo metal chelate dyes, and is suitably used for a recording layer in an optical recording medium for high-speed recording. In formula (1), ring A is a nitrogen-containing heteroaromatic ring which may have a substituent and with which another aromatic or aliphatic ring may be condensed; one of Z<SB>1</SB>and Z<SB>2</SB>is a group having an active hydrogen and the other is a hydrogen atom; R<SB>1</SB>and R<SB>2</SB>are, each independently, an alkyl group which may have a substituent or an aryl group which may have a substituent; ring B is a ring which is connected by a 1-6C chain; R<SB>3</SB>is, each independently, a hydrogen atom, an alkyl group which may have a substituent or an aryl group which may have a substituent; and n is an integer of 1 to 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an azo metal chelate dye and the like, and more particularly to an azo metal chelate dye comprising an azo dye compound having a specific chemical structure and a metal, and an optical recording medium using the azo metal chelate dye.

In recent years, optical recording using laser light has been particularly developed in order to enable recording and storage of high-density information and reproduction thereof. As a medium used for recording, a magneto-optical recording medium, a phase change optical recording medium, an organic dye-based optical recording medium, and the like have been proposed. Among these, the organic dye-based optical recording medium is considered to be significant in that the manufacturing process is simple and the medium can be provided at low cost.
As an organic dye-based optical recording medium, a recordable compact disc (CD-R) or the like has already been mass-produced. Various dyes such as cyanine dyes, phthalocyanine dyes, metal chelate dyes have been proposed as dyes for use in the recording layer of CD-R, and the present inventors have proposed an optical system using an azo metal chelate dye having excellent light resistance and environmental resistance. A recording medium was proposed (see Patent Document 1 and Patent Document 2).
Recently, a medium capable of high-speed recording has been demanded as the performance of computers has increased, and the present inventors have also been able to record at a speed more than 8 times the conventional speed. An azo metal chelate dye applicable to the recording layer has been proposed (see Patent Document 3).

Japanese Patent Publication No. 07-051673 Japanese Patent Publication No. 08-019341 JP-A-2002-114922

By the way, as a recording layer material that can cope with such high-speed recording in an organic dye-based optical recording medium, it is considered necessary to increase the absorption wavelength of the recording material with respect to laser light. Can be mentioned.
However, an effective compound design for increasing the absorption wavelength of a dye used in a recording layer of an organic dye-based optical recording medium with respect to a laser beam has not been found so far.
The present invention has been made to solve such problems, and an object of the present invention is to provide a dye suitably used for a recording layer of an optical recording medium in which high-speed recording is performed. .
Another object of the present invention is to provide an optical recording medium capable of high-speed recording.

  Under such a purpose, the present inventors have conducted intensive studies, and as a result, azo metal chelate dyes formed from an azo compound synthesized using a compound represented by the following formula as a coupler and a metal are used in various solvents. The invention was completed by finding that it has high solubility.

  That is, the gist of the present invention is an azo metal chelate dye comprising an azo compound represented by the following formula (1) and a metal atom.

(In formula (1), ring A is a nitrogen-containing heteroaromatic ring which may have a substituent and may be condensed with another aromatic or aliphatic ring. Z ₁ or Z ₂ One of these is a group having active hydrogen, and the other is a hydrogen atom, and R ₁ and R ₂ are each independently an alkyl group which may have a substituent or an aryl which may have a substituent. Ring B is a ring connected by a carbon chain having 1 to 6 atoms, each R ₃ independently has a hydrogen atom, an alkyl group which may have a substituent, or a substituent. And n is an integer of 1 to 6.)
Here, the formula (1) is a 6-membered ring in which the ring B is connected by a carbon chain having 3 carbon atoms, and is preferably an azo compound represented by the following formula (2).

(In formula (2), ring A is a nitrogen-containing heteroaromatic ring which may have a substituent and may be condensed with another aromatic or aliphatic ring. Z ₁ or Z ₂ One of these is a group having active hydrogen, and the other is a hydrogen atom, and R ₁ and R ₂ are each independently an alkyl group which may have a substituent or an aryl which may have a substituent. R ₃ is each independently a hydrogen atom, an alkyl group that may have a substituent, or an aryl group that may have a substituent, and n is an integer of 1 to 3. )
Further, in the formula (2), the substitution position of R ₃ is an α-position carbon atom adjacent to the nitrogen atom forming the ring B, and is preferably an azo compound represented by the following formula (3).

(In Formula (3), Ring A is a nitrogen-containing heteroaromatic ring which may have a substituent and may be condensed with another aromatic or aliphatic ring. Z ₁ or Z ₂ One represents a group having active hydrogen, the other represents a hydrogen atom, _one of Z ₁ or Z ₂ is a group having active hydrogen, and the other is a hydrogen atom, R ₁ and R ₂ are each independently , An alkyl group which may have a substituent or an aryl group which may have a substituent, R ₃ may have a hydrogen atom, an alkyl group which may have a substituent or a substituent. Good aryl group.)
In the azo metal chelate dye to which the present invention is applied, the metal is preferably Ni, Co, Cu or Pd.

  Next, the present invention provides an optical recording medium having a recording layer on which information is recorded and / or reproduced by irradiated light on a substrate, and the recording layer is an azo compound represented by the following formula (1). It is grasped as an optical recording medium characterized by containing an azo metal chelate dye composed of a compound and a metal atom.

(In formula (1), ring A is a nitrogen-containing heteroaromatic ring which may have a substituent and may be condensed with another aromatic or aliphatic ring. Z ₁ or Z ₂ One of these is a group having active hydrogen, and the other is a hydrogen atom, and R ₁ and R ₂ are each independently an alkyl group which may have a substituent or an aryl which may have a substituent. Ring B is a ring connected by a carbon chain having 1 to 6 atoms, each R ₃ independently has a hydrogen atom, an alkyl group which may have a substituent, or a substituent. And n is an integer of 1 to 6.)

  ADVANTAGE OF THE INVENTION According to this invention, the pigment | dye used suitably for the recording layer of the optical recording medium in which high speed recording is performed is provided.

Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment of the present invention) will be described in detail.
The azo metal chelate dye to which the present embodiment is applied is formed by a chelate bond between an azo compound represented by the following formula (1) and a metal. The molecular weight of the azo compound represented by the formula (1) is usually 2000 or less, preferably 1500 or less. An excessively high molecular weight is not preferable because the gram extinction coefficient decreases. However, it is usually 150 or more, preferably 200 or more. If the molecular weight is excessively small, light cannot be absorbed sufficiently and recording cannot be performed.

In the azo compound represented by the formula (1), R ₁ and R ₂ are each independently an alkyl group which may have a substituent or an aryl group which may have a substituent. Examples of the alkyl group include 1 to 6 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group. The linear or branched alkyl group of these is mentioned. Examples of the aryl group include aryl groups that may have a substituent such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. Among these, a linear or branched alkyl group having 1 to 6 carbon atoms is preferable.
Examples of the substituent that R ₁ and R ₂ may have include the following. For example, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentyloxy group, n-hexyloxy group, etc. Alkoxy groups such as: methoxymethoxy group, ethoxymethoxy group, propoxymethoxy group, methoxyethoxy group, ethoxyethoxy group, propoxyethoxy group, methoxypropoxy group, ethoxypropoxy group, methoxybutoxy group, ethoxybutoxy group and the like. Alkoxyalkoxy groups of: methoxymethoxymethoxy group, methoxymethoxyethoxy group, methoxyethoxymethoxy group, methoxyethoxyethoxy group, ethoxymethoxymethoxy group, ethoxymethoxyethoxy group, ethoxyethoxymethoxy group, ethoxyethoxy Alkoxyalkoxyalkoxy groups having 3 to 15 carbon atoms such as toxyl groups; allyloxy groups; aryl groups having 6 to 18 carbon atoms such as phenyl groups, tolyl groups, xylyl groups, naphthyl groups; phenoxy groups, tolyloxy groups, xylyloxy groups, naphthyl groups C6-C18 aryloxy group such as oxy group; cyano group; nitro group; hydroxy group; tetrahydrofuryl group; carbon number such as methylamino group, ethylamino group, n-propylamino group, n-butylamino group An alkylamino group having 1 to 6 carbon atoms; a dialkylamino group having 1 to 12 carbon atoms such as a dimethylamino group, a diethylamino group, a di-n-propylamino group, a di-n-butylamino group; a methylsulfonylamino group, an ethylsulfonylamino group; Group, n-propylsulfonylamino group, isopropylsulfonylamino group An alkylsulfonylamino group having 1 to 6 carbon atoms such as a group, n-butylsulfonylamino group, sec-butylsulfonylamino group, tert-butylsulfonylamino group, n-pentylsulfonylamino group, n-hexylsulfonylamino group; fluorine Halogen atoms such as atom, chlorine atom, bromine atom, iodine atom; methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, isopropoxycarbonyl group, n-butoxycarbonyl group, sec-butoxycarbonyl group, tert-butoxycarbonyl Group, an alkoxycarbonyl group having 2 to 7 carbon atoms such as an n-pentyloxycarbonyl group and an n-hexyloxycarbonyl group; a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropyl group; Alkylcarbonyloxy groups having 2 to 7 carbon atoms such as rubonyloxy group, n-butylcarbonyloxy group, sec-butylcarbonyloxy group, tert-butylcarbonyloxy group, n-pentylcarbonyloxy group, n-hexylcarbonyloxy group Etc.
Of R ₁ and R _2, a linear or branched alkyl group having no substituent and an alkyl group substituted with a halogen are particularly preferable.

  In formula (1), ring B is a ring connected by a carbon chain having 1 to 6 atoms. Among these, a 5-membered ring to a 7-membered ring are preferable as shown below, and within this range, it is easy to obtain starting materials, and it is considered that the stability of the resulting compound is high.

  In particular, an azo compound represented by the following formula (2) in which the ring B is a 6-membered ring is particularly preferable.

In Formula (1), each R ₃ is independently a hydrogen atom, an alkyl group that may have a substituent, or an aryl group that may have a substituent. N is an integer of 1 to 3, and a plurality of R ₃ may be present on the ring B. Specific examples of R ₃ include the following. For example, straight chain having 1 to 6 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, etc. Or a branched alkyl group; a cyclic alkyl group having 3 to 6 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group; methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, an alkoxy group having 1 to 6 carbon atoms such as a sec-butoxy group, a tert-butoxy group, an n-pentyloxy group, and an n-hexyloxy group; An alkylcarbonyl group having 1 to 7 carbon atoms such as a pivaloyl group, a hexanoyl group, a heptanoyl group; a vinyl group; -C2-C6 linear or branched alkenyl group such as propenyl group, allyl group, isopropenyl group, 2-ptenyl group, 1,3-butadienyl group, 1-pentenyl group, 1-hexenyl group, etc .; cyclopentenyl A cyclic alkenyl group having 3 to 6 carbon atoms such as a cyclohexenyl group, a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom or an iodine atom; a formyl group; a hydroxyl group; a carboxyl group; a hydroxymethyl group, a hydroxyethyl group, etc. A hydroxyalkyl group having 1 to 6 carbon atoms of methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, isopropoxycarbonyl group, n-butoxycarbonyl group, sec-butoxycarbonyl group, tert-butoxycarbonyl group, n- Pentyloxycarbonyl group, n-hexyloxy A C2-C7 alkoxycarbonyl group such as a rubonyl group; a nitro group; a cyano group; an amino group; a C1-C6 such as a methylamino group, an ethylamino group, an n-propylamino group, and an n-butylamino group Alkylamino group; dimethylamino group, diethylamino group, di-n-propylamino group, di-n-butylamino group and other C1-C12 dialkylamino groups; methoxycarbonylmethyl group, ethoxycarbonylmethyl group, n- C3-C7 alkoxycarbonylalkyl group such as propoxycarbonylmethyl group, isopropoxycarbonylethyl group; methylthio group, ethylthio group, n-propylthio group, sec-butylthio group, tert-butylthio group, n-pentylthio group, n An alkylthio group having 1 to 6 carbon atoms such as a hexylthio group; Carbons such as a rusulfonyl group, an ethylsulfonyl group, an n-propylsulfonyl group, an isopropylsulfonyl group, an n-butylsulfonyl group, a sec-butylsulfonyl group, a tert-butylsulfonyl group, an n-pentylsulfonyl group, and an n-hexylsulfonyl group Examples thereof include an alkylsulfonyl group having 1 to 6 carbon atoms; an aryl group having 6 to 16 carbon atoms which may have a substituent; an arylcarbonyl group having 7 to 17 carbon atoms which may have a substituent.
Among these, an unsubstituted linear or branched alkyl group having 1 to 10 carbon atoms and an alkyl group substituted with halogen are preferable, and a methyl group and an ethyl group are more preferable.
Furthermore, in the formula (1), when the substitution position of R ₃ is an α-position carbon atom adjacent to the nitrogen atom forming the ring B and is an azo compound represented by the following formula (3), The azo metal chelate dye formed is excellent in storage stability.

In Formula (1), one of Z ₁ or Z ₂ is a group having active hydrogen, and the other is a hydrogen atom. Examples of the group having active hydrogen include an —SH group, —SO ₂ H group, —SO ₃ H group, —NH ₂ group, —NHR ₄ group, —OH group, —CO ₂ H group, —B (OH ) ₂ groups, —PO (OH) ₂ groups, —NHCOH groups, —NHCOR ₄ groups, —NHSO ₂ R ₄ groups, and the like. Among them preferred are, -SO ₃ H group, -NH ₂ group, -NHR ₄ group, -OH group, -CO ₂ H group, -NHCOH group, -NHCOR ₄ radical, an -NHSO ₂ R ₄ group, in particular preferred are, -SO ₃ H group, -CO ₂ H group, -OH group, a -NHSO ₂ R ₄ groups.
Here, examples of R ₄ include carbon such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, and n-hexyl group. A linear or branched alkyl group which may have a substituent of 1 to 6; a substituent having 6 to 12 carbon atoms such as a phenyl group, a tolyl group, a xylyl group or a naphthyl group; A good phenyl group is mentioned. R ₄ may be substituted with a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom.

In formula (1), ring A is a nitrogen-containing heteroaromatic ring which may have a substituent and may be condensed with another aromatic or aliphatic ring. Examples of the structure of ring A include a structure in which one to three 5-membered rings and / or 6-membered rings are condensed. For example, a thiazole ring, imidazole ring, pyrazole ring, isoxazole ring, pyridine ring, benzthiazole ring and benzimidazole ring are preferable, and a thiazole ring, imidazole ring, pyrazole ring, isoxazole ring, benzthiazole ring and benzimidazole ring are more preferable.
The specific structure of ring A is illustrated below.

In the above specific examples, R ₅ is a hydrogen atom or a substituent. Examples of the substituent include carbon such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group and n-hexyl group. A linear or branched alkyl group having 1 to 6 carbon atoms; a cyclic alkyl group having 3 to 6 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group; methoxy group, ethoxy group, n-propoxy group, isopropoxy group Group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentyloxy group, n-hexyloxy group, etc., an alkoxy group having 1 to 6 carbon atoms; acetyl group, propionyl group, petityl group, isoptyryl group , Valeryl group, isovaleryl group, pivaloyl group, hexanoyl group, heptanoyl group, etc. A straight chain having 2 to 6 carbon atoms such as vinyl group, 1-propenyl group, allyl group, isopropenyl group, 2-ptenyl group, 1,3-butadienyl group, 1-pentenyl group, 1-hexenyl group or the like A branched alkenyl group; a cyclic alkenyl group having 3 to 6 carbon atoms such as a cyclopentenyl group and a cyclohexenyl group; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom; a formyl group; a hydroxyl group; a carboxyl group; A hydroxyalkyl group having 1 to 6 carbon atoms such as a methyl group and a hydroxyethyl group; a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an isopropoxycarbonyl group, an n-butoxycarbonyl group, a sec-butoxycarbonyl group, a tert -Butoxycarbonyl group, n-pentyloxycarbonyl group C2-C7 alkoxycarbonyl group such as n-hexyloxycarbonyl group; nitro group; cyano group; amino group; carbon number such as methylamino group, ethylamino group, n-propylamino group, n-butylamino group An alkylamino group having 1 to 6 carbon atoms; a dialkylamino group having 1 to 12 carbon atoms such as a dimethylamino group, a diethylamino group, a di-n-propylamino group and a di-n-butylamino group; a methoxycarbonylmethyl group and an ethoxycarbonylmethyl group; Group, alkoxycarbonylalkyl group having 3 to 7 carbon atoms such as n-propoxycarbonylmethyl group, isopropoxycarbonylethyl group; methylthio group, ethylthio group, n-propylthio group, sec-butylthio group, tert-butylthio group, n- 1 to 6 carbon atoms such as pentylthio group and n-hexylthio group Alkylthio group; methylsulfonyl group, ethylsulfonyl group, n-propylsulfonyl group, isopropylsulfonyl group, n-butylsulfonyl group, sec-butylsulfonyl group, tert-butylsulfonyl group, n-pentylsulfonyl group, n-hexylsulfonyl group arylcarbonyl group substituents from carbon atoms 7 have a 17; a substituted from even carbon atoms 6 16 aryl group, alkyl sulfonyl group having 1 to 6 carbon atoms equal -CR ₆ ═C (CN) R ₇ (wherein R ₆ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms as defined in R ₅ described above, and R ₇ is a cyano group or And R ₅ is an alkoxycarbonyl group having 2 to 7 carbon atoms as defined above. ) And the like.
R ₅ may be the same or different. R ₅ may be bonded to each other to form a ring condensed with ring A.

  The metal used in the azo metal chelate dye to which the present embodiment is applied is not particularly limited as long as it is an element capable of taking a valence of 2 or more, and a transition metal is usually preferable. Specifically, Mg, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ru, Rh, Pd, In, Sn, Hf, Os, Pt, and Hg are preferable. Co, Ni, Cu, and Pd are more preferable from the viewpoints of good shape of absorption spectrum, solubility in various solvents, light resistance, and durability.

Specific examples of the azo metal chelate dye to which the present embodiment is applied are shown below. The exemplified azo metal chelate dye is represented by a structure in which two ligands are coordinated to one metal, but these are presumed structures, and one ligand is coordinated to one metal. There may also be a structured structure.
Examples of the cobalt-based azo metal chelate dye include the following.

  Examples of the copper-based azo metal chelate dye include the following.

  Examples of the palladium azo metal chelate dye include the following.

  Examples of the nickel-based azo metal chelate dye include the following.

Next, an optical recording medium to which this embodiment is applied will be described. The optical recording medium to which the present embodiment is applied includes at least a substrate and a recording layer containing an azo metal chelate dye composed of an azo compound represented by formula (1) and a metal atom. If necessary, an undercoat layer, a reflective layer, a protective layer, etc. may be further provided.
FIG. 1 is a diagram for explaining an optical recording medium to which the present embodiment is applied. An optical recording medium 10 shown in FIG. 1 includes a substrate 1 made of a light-transmitting material, a recording layer 2 provided on the substrate 1, and a reflective layer 3 and a protective layer 4 laminated on the recording layer 2. They are stacked in order. In the optical recording medium 10, information is recorded / reproduced by laser light emitted from the substrate 1 side.
For convenience of explanation, in the optical recording medium 10, the side where the protective layer 4 exists is the upper side, the side where the substrate 1 exists is the lower side, and the surfaces of each layer corresponding to these directions are the upper and lower surfaces of each layer, respectively. And

As the substrate 1, various materials can be used as long as they are basically transparent at the wavelengths of recording light and reproducing light. Examples of such materials include polycarbonate resins, vinyl chloride resins, polymethyl methacrylate acrylic resins, polystyrene resins, epoxy resins, vinyl acetate resins, polyester resins, polyethylene resins, polypropylene resins, Polymer materials such as polyimide resins and amorphous polyolefins, and inorganic materials such as glass are used, but polycarbonate resins are preferred from the viewpoints of high productivity, cost, moisture absorption resistance, and the like.
The substrate 1 is formed into a disk shape by an injection molding method or the like using these substrate materials. If necessary, guide grooves and pits may be formed on the surface of the substrate 1. Such guide grooves and pits are preferably provided when the substrate 1 is molded, but can also be provided on the substrate 1 using an ultraviolet curable resin layer.

The recording layer 2 is formed by using an azo metal chelate dye composed of an azo compound represented by the formula (1) and a metal atom, on the substrate 1 directly or if necessary with an undercoat layer or the like. The film thickness of the recording layer 2 is not particularly limited, but is usually 10 nm or more, but 5000 nm or less. Examples of the method for forming the recording layer 2 include commonly used thin film forming methods such as a vacuum deposition method, a sputtering method, a doctor blade method, a casting method, a spinner method, and an immersion method. Among them, the spinner method is preferable from the viewpoint of mass productivity and cost. When the recording layer 2 is formed by the spinner method, the rotational speed is preferably 100 to 5000 rpm, and after spin coating, heating or solvent vapor treatment may be performed as necessary.
The coating solvent used when the recording layer 2 is formed by a coating method such as a doctor blade method, a casting method, a spinner method, or a dipping method may be any solvent that does not attack the substrate 1 and is not particularly limited. For example, ketone alcohol solvents such as diacetone alcohol and 3-hydroxy-3-methyl-2-butanone; cellosolv solvents such as methyl cellosolve and ethyl cellosolve; chain hydrocarbon solvents such as n-hexane and n-octane Cyclic hydrocarbon solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, n-butylcyclohexane, t-butylcyclohexane and cyclooctane; perfluoroalkyl alcohols such as tetrafluoropropanol, octafluoropentanol and hexafluorobutanol Examples of the solvent include hydroxycarboxylic acid ester solvents such as methyl lactate, ethyl lactate, and methyl isobutyrate.

  When the recording layer 2 is formed, additives such as a quencher, an ultraviolet absorber, and an adhesive can be mixed as necessary. Moreover, it is also possible to introduce | transduce as a substituent which has such an effect. For example, the singlet oxygen quencher added to improve the light resistance and durability of the recording layer 2 includes bisdithiols such as acetylacetonate, bisdithio-α-diketone and bisphenyldithiol, and thiocatechol. And metal complexes such as salicylaldehyde oxime and thiobisphenolate are preferred. An amine compound is also suitable.

In the recording layer 2, other dyes may be used in combination for improving the recording characteristics and the like. Other usable azo dyes or azo metal chelate dyes, cyanine dyes, squarylium dyes, naphthoquinone dyes, anthraquinone dyes, porphyrin dyes, tetrapyraporphyrazine dyes, indophenol dyes , Pyrylium dye, thiopyrylium dye, azurenium dye, triphenylmethane dye, xanthene dye, indanthrene dye, indigo dye, thioindigo dye, merocyanine dye, bispyromethene dye, thiazine dye, acridine Other types of dyes such as a dye, an oxazine dye and an indoaniline dye may be used. However, it is a condition for use to dissolve in the solvent system used for coating.
Examples of the thermal decomposition accelerator for the dye include metal compounds such as metal anti-knock agents, metallocene compounds, and acetylacetonato metal complexes. Furthermore, a binder, a leveling agent, an antifoaming agent, etc. can also be used together as needed. Preferable binders include polyvinyl alcohol, polyvinyl pyrrolidone, nitrocellulose, cellulose acetate, ketone resin, acrylic resin, polystyrene resin, urethane resin, polyvinyl butyral, polycarbonate, polyolefin and the like.

The reflective layer 3 is formed on the recording layer 2. The thickness of the reflective layer 3 is usually 50 nm or more, provided that it is 300 nm or less. As a material for forming the reflective layer 3, a material having a sufficiently high reflectivity with respect to the wavelength of the reproduction light, for example, a metal such as Au, Al, Ag, Cu, Ti, Cr, Ni, Pt, Ta and Pd alone or It can be used as an alloy. Among these, Au, Al, and Ag have high reflectivity and are suitable as the material for the reflective layer. In particular, Ag and an Ag alloy are preferable because they are excellent in high reflectance and high thermal conductivity.
In addition to these metal atoms, the reflective layer 3 may contain the following. For example, Mg, Se, Hf, V, Nb, Ru, W, Mn, Re, Fe, Co, Rh, Ir, Cu, Zn, Cd, Ga, In, Si, Ge, Te, Pb, Po, Sn, Mention may be made of metals such as Bi and metalloids. Among them, those containing Ag as a main component are inexpensive and tend to improve the reflectivity when combined with an azo metal chelate dye. Further, when a print receiving layer described later is provided, the ground color is white and beautiful. Is particularly preferable. Here, the main component means one having a content of 50% or more. It is also possible to form a multilayer film by alternately stacking a low refractive index thin film and a high refractive index thin film using a material other than metal, and use it as the reflective layer 3.
Examples of methods for forming the reflective layer 3 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 1 or below the reflective layer 3 in order to improve reflectivity, improve recording characteristics, and improve adhesion. .

The protective layer 4 is not particularly limited as long as it is formed on the reflective layer 3 and protects the reflective layer 3 from external force. For example, examples of the organic substance include a thermoplastic resin, a thermosetting resin, an electron beam curable resin, and a UV curable resin. Examples of inorganic substances include SiO ₂ , SiN ₄ , MgF ₂ , SnO _{2 and the} like. A thermoplastic resin, a thermosetting resin, or the like can be formed by dissolving in an appropriate solvent, applying a coating solution, and drying. The UV curable resin can be formed by preparing a coating solution as it is or by dissolving it in a suitable solvent, and then applying the coating solution and curing it by irradiating with UV light. Examples of the UV curable resin include acrylate resins such as urethane acrylate, epoxy acrylate, and polyester acrylate. 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 4, similarly to the recording layer 2, a coating method such as a spin coating method or a casting method, a method such as a sputtering method or a chemical vapor deposition method is used. Of these, spin coating is preferred. The film thickness of the protective layer 4 is usually 0.1 μm or more, preferably 3 μm or more, more preferably 5 μm or more. However, it is usually 100 μm or less, preferably 30 μm or less, more preferably 20 μm or less.

As described above, the layer structure of the optical recording medium 10 has been described by taking the structure in which the substrate 1, the recording layer 2, the reflective layer 3, and the protective layer 4 are laminated in this order as an example. You may take a structure. For example, another substrate may be bonded to the upper surface of the protective layer 4 in the above layer structure, or to the upper surface of the reflective layer 3 by omitting the protective layer 4 from the above layer structure. The substrate at this time may be the substrate itself without any layers, or may have an arbitrary layer such as a reflective layer on the bonded surface or the opposite surface. Similarly, the optical recording medium 10 having the above layer structure and the optical recording medium in which the protective layer is omitted from the above layer structure are arranged so that the upper surfaces of the protective layer 4 and / or the reflective layer 3 face each other. Two sheets may be pasted together. Furthermore, a print receiving layer can be further formed on the protective layer 4 provided on the reflective layer 3 or on a substrate bonded to the surface of the reflective layer 3.
Recording on the optical recording medium 10 obtained in this way is performed by irradiating the recording layer 2 provided on both surfaces or one surface of the substrate 1 with laser light. In the portion irradiated with the laser beam, thermal deformation of the recording layer such as decomposition, heat generation, and melting due to absorption of laser beam energy occurs. The recorded information is reproduced by reading the difference in reflectance between the portion where the thermal deformation is caused by the laser beam and the portion where it is not.
The laser used for recording / reproduction is not particularly limited, and examples thereof include a dye laser capable of selecting a wavelength in a wide range in the visible region, N2, He—Cd, Ar, He—Ne, ruby, and a semiconductor laser. In view of lightness, ease of handling, compactness, cost, etc., a semiconductor laser is preferable.

Hereinafter, the present embodiment will be specifically described by way of examples. In addition, an Example does not limit this Embodiment, unless the summary is exceeded.
(Example 1)
(Diazo coupling)
2-amino-6-octylbenzothiazole (1a, 1.5 g) is dissolved in acetic acid (10 ml), phosphoric acid (8.6 g), sulfuric acid (2.0 g), cooled to 5 ° C. or lower, and 43% nitrosylsulfuric acid (1.9 g) is added dropwise to form a diazo solution did. A coupler solution was prepared by dissolving 1.9 g of Compound 1b, 0.2 g of urea and 1.0 g of sodium acetate in 65 ml of methanol, and adjusting the pH to 3.5 with aqueous ammonia. The coupler solution was cooled to 5 ° C. or lower, and the previously prepared diazo solution and aqueous ammonia were added dropwise so as to maintain the pH between 3 and 4. After completion of the addition, the pH was further adjusted to 6 with aqueous ammonia. The precipitated solid was collected by filtration and purified to obtain azo compound 1c.
(Mounting)
Azo compound 1c was dissolved in 21 ml of methanol, and the insoluble material was filtered off. Separately, 0.5 g of nickel acetate tetrahydrate was dissolved in 5 ml of methanol and added dropwise to the methanol solution of the azo compound. The precipitated crystals were collected by filtration and purified to obtain 0.4 g of the intended azo nickel chelate dye 1d (estimated structure). This azo nickel chelate dye 1d had a maximum absorption wavelength in chloroform of 713 nm and a Gram extinction coefficient of 98 L / gcm. As a result, it is understood that the azo nickel chelate dye 1d has a longer absorption wavelength and is suitable for high speed recording.
(Example of coating film creation)
0.3 g of the azo nickel chelate dye 1d was dissolved in 10 ml of octafluoropentanol and filtered through a filter having a pore size of 220 nm to obtain a dye solution. This dye solution was dropped on an injection-molded polycarbonate resin substrate (diameter 12 cm) in which guide grooves were previously formed, and applied by a spinner method. After application, it was dried at 80 ° C. for 5 minutes. The maximum absorption wavelength of the coating film was 728 nm. Further, the coating film was placed in a high-temperature and high-humidity bath under conditions of temperature: 85 ° C., humidity: 85%, and time: 200 Hr, and a storage stability test was performed. The maximum absorption wavelength of the coating film after the storage stability test was 679 nm. Thereby, it turns out that the azo nickel chelate pigment | dye 1d is excellent in storage stability.

(Example 2)
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 2a and 2b, whereby azo compound 2c and subsequent azo nickel chelate dye 2d were obtained.
The maximum absorption wavelength of this azonickel chelate dye 2d in chloroform was 710 nm, the Gram extinction coefficient was 85 L / gcm, and the maximum absorption wavelength of the coating film was 732 nm. As a result, it can be seen that the absorption wavelength of the azo nickel chelate dye 2d is increased. As a result of conducting a storage stability test in the same manner as in Example 1, it can be seen that the maximum absorption wavelength after the storage stability test is 110 nm, and the azo nickel chelate dye 2d is excellent in storage stability.

(Example 3)
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 3a and 3b to obtain azo compound 3c and subsequently azo nickel chelate dye 3d.
The maximum absorption wavelength of this azonickel chelate dye 3d in chloroform was 702 nm, the Gram extinction coefficient was 95 L / gcm, and the maximum absorption wavelength of the coating film was 720 nm. As a result, it can be seen that the absorption wavelength of the azo nickel chelate dye 3d is increased.

Example 4
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 4a and 4b to obtain azo compound 4c and subsequently azo nickel chelate dye 4d.
The maximum absorption wavelength of this azonickel chelate dye 4d in chloroform was 702 nm, the gram extinction coefficient was 104 L / gcm, and the maximum absorption wavelength of the coating film was 726 nm. As a result, it can be seen that the absorption wavelength of the azo nickel chelate dye 4d is increased.

(Example 5)
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 5a and 5b, whereby azo compound 5c and subsequently azo nickel chelate dye 5d were obtained.
The maximum absorption wavelength of this azonickel chelate dye 5d in chloroform was 711 nm, the Gram extinction coefficient was 71 L / gcm, and the maximum absorption wavelength of the coating film was 727 nm. As a result, it can be seen that the absorption wavelength of the azo nickel chelate dye 5d is increased.

(Example 6)
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 6a and 6b, whereby azo compound 6c and subsequently azo nickel chelate dye 6d were obtained.
The maximum absorption wavelength of this azonickel chelate dye 6d in chloroform was 710 nm, the Gram extinction coefficient was 98 L / gcm, and the maximum absorption wavelength of the coating film was 732 nm. As a result, it can be seen that the absorption wavelength of the azo nickel chelate dye 6d is increased.

(Example 7)
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 7a and 7b, whereby azo compound 7c and subsequent azo nickel chelate dye 7d were obtained.
The maximum absorption wavelength of this azo nickel chelate dye 7d in chloroform was 717 nm, the Gram extinction coefficient was 92 L / gcm, and the maximum absorption wavelength of the coating film was 727 nm. As a result of conducting a storage stability test in the same manner as in Example 1, the maximum absorption wavelength after the storage stability test was 720 nm. As a result, it is understood that the azo nickel chelate dye 7d has a longer absorption wavelength and is excellent in storage stability.

(Example 8)
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 8a and 8b, whereby azo compound 8c and subsequently azo nickel chelate dye 8d were obtained.
The maximum absorption wavelength of this azonickel chelate dye 8d in chloroform was 710 nm, the Gram extinction coefficient was 107 L / gcm, and the maximum absorption wavelength of the coating film was 728 nm. As a result, it can be seen that the absorption wavelength of the azo nickel chelate dye 8d is increased.

Example 9
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 9a and 9b, whereby azo compound 9c and subsequently azo nickel chelate dye 9d were obtained.
The maximum absorption wavelength of this azonickel chelate dye 9d in chloroform was 711 nm, the Gram extinction coefficient was 113 L / gcm, and the maximum absorption wavelength of the coating film was 732 nm. As a result of conducting a storage stability test in the same manner as in Example 1, the maximum absorption wavelength after the storage stability test was 59 nm. As a result, it can be seen that the absorption wavelength of the azo nickel chelate dye 9d is increased.

(Example 10)
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 10a and 10b, whereby azo compound 10c and subsequently azo nickel chelate dye 10d were obtained.
The maximum absorption wavelength of this azonickel chelate dye 10d in chloroform was 710 nm, the Gram extinction coefficient was 113 L / gcm, and the maximum absorption wavelength of the coating film was 732 nm. As a result, it can be seen that the absorption wavelength of the azo nickel chelate dye 10d is increased.

(Example 11)
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 11a and 11b, whereby azo compound 11c and subsequently azo nickel chelate dye 11d were obtained.
The maximum absorption wavelength of this azonickel chelate dye 11d in chloroform was 715 nm, the Gram extinction coefficient was 93 L / gcm, and the maximum absorption wavelength of the coating film was 750 nm. As a result, it can be seen that the absorption wavelength of the azo nickel chelate dye 11d is increased.

(Example 12)
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 12a and 12b, whereby azo compound 12c and subsequently azo nickel chelate dye 12d were obtained.
The maximum absorption wavelength of this azonickel chelate dye 12d in chloroform was 709 nm, the Gram extinction coefficient was 61 L / gcm, and the maximum absorption wavelength of the coating film was 727 nm. As a result, it can be seen that the absorption wavelength of the azo nickel chelate dye 12d is increased.

(Example 13)
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 13a and 13b, whereby azo compound 13c and subsequent azo nickel chelate dye 13d were obtained.
The maximum absorption wavelength of this azonickel chelate dye 13d in chloroform was 712 nm, the Gram extinction coefficient was 99 L / gcm, and the maximum absorption wavelength of the coating film was 732 nm. As a result, it can be seen that the absorption wavelength of the azo nickel chelate dye 13d is increased.

(Example 14)
The same procedure as in Example 1 was carried out except that the starting materials were changed to compounds 14a and 14b, whereby azo compound 14c and azo nickel chelate dye 14d were obtained subsequently.
The maximum absorption wavelength of this azonickel chelate dye 14d in chloroform was 709 nm, the Gram extinction coefficient was 72 L / gcm, and the maximum absorption wavelength of the coating film was 725 nm. As a result, it can be seen that the absorption wavelength of the azo nickel chelate dye 14d is increased.

(Comparative Example 1)
The same procedure as in Example 1 was carried out except that the starting materials were changed to the compounds 101a and 101b, whereby an azo compound 101c and an azo nickel chelate dye 101d were obtained subsequently.
The maximum absorption wavelength of this azonickel chelate dye 101d in chloroform was 686 nm, the Gram extinction coefficient was 124 L / gcm, and the maximum absorption wavelength of the coating film was 714 nm. As a result, it is understood that the azo nickel chelate dye 101d is not suitable for high-speed recording because the absorption wavelength is not observed in the long wavelength region.

(Comparative Example 2)
The same procedure as in Example 1 was carried out except that the starting materials were changed to the compounds 102a and 102b, whereby an azo compound 102c and subsequently an azo nickel chelate dye 102d were obtained.
The maximum absorption wavelength of this azonickel chelate dye 102d in chloroform was 681 nm, the gram extinction coefficient was 122 L / gcm, and the maximum absorption wavelength of the coating film was 716 nm. As a result, it is understood that the absorption wavelength of the azo nickel chelate dye 102d is not observed in the long wavelength region.

(Comparative Example 3)
The same procedure as in Example 1 was carried out except that the starting materials were changed to the compounds 103a and 103b, whereby an azo compound 103c and subsequently an azo nickel chelate dye 103d were obtained.
The maximum absorption wavelength of this azonickel chelate dye 103d in chloroform was 676 nm, the Gram extinction coefficient was 107 L / gcm, and the maximum absorption wavelength of the coating film was 711 nm. As a result, it is understood that the absorption wavelength of the azo nickel chelate dye 103d is not observed in the long wavelength region.

(Comparative Example 4)
The same procedure as in Example 1 was carried out except that the starting materials were changed to the compounds 104a and 104b. Thus, an azo compound 104c and subsequently an azo nickel chelate dye 104d were obtained.
The maximum absorption wavelength of this azonickel chelate dye 104d in chloroform was 670 nm, the Gram extinction coefficient was 149 L / gcm, and the maximum absorption wavelength of the coating film was 710 nm. As a result, it is understood that the absorption wavelength of the azo nickel chelate dye 104d is not observed in the long wavelength region.

(Comparative Example 5)
The same procedure as in Example 1 was carried out except that the starting materials were changed to the compounds 105a and 105b, whereby an azo compound 105c and an azo nickel chelate dye 105d were obtained subsequently.
The maximum absorption wavelength of this azonickel chelate dye 105d in chloroform was 684 nm, the Gram extinction coefficient was 118 L / gcm, and the maximum absorption wavelength of the coating film was 712 nm. As a result, it is understood that the absorption wavelength of the azo nickel chelate dye 105d is not observed in the long wavelength region.

It is a figure explaining the optical recording medium with which this Embodiment is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Recording layer, 3 ... Reflective layer, 4 ... Protective layer, 10 ... Optical recording medium

Claims (5)

An azo metal chelate dye comprising an azo compound represented by the following formula (1) and a metal atom.

(In formula (1), ring A is a nitrogen-containing heteroaromatic ring which may have a substituent and may be condensed with another aromatic or aliphatic ring. Z ₁ or Z ₂ One of these is a group having active hydrogen, and the other is a hydrogen atom, and R ₁ and R ₂ are each independently an alkyl group which may have a substituent or an aryl which may have a substituent. Ring B is a ring connected by a carbon chain having 1 to 6 atoms, each R ₃ independently has a hydrogen atom, an alkyl group which may have a substituent, or a substituent. And n is an integer of 1 to 6.) The azo metal chelate according to claim 1, wherein the formula (1) is an azo compound represented by the following formula (2), wherein the ring B is a 6-membered ring connected by a carbon chain having 3 carbon atoms. Pigment.

(In formula (2), ring A is a nitrogen-containing heteroaromatic ring which may have a substituent and may be condensed with another aromatic or aliphatic ring. Z ₁ or Z ₂ One of these is a group having active hydrogen, and the other is a hydrogen atom, and R ₁ and R ₂ are each independently an alkyl group which may have a substituent or an aryl which may have a substituent. R ₃ is each independently a hydrogen atom, an alkyl group that may have a substituent, or an aryl group that may have a substituent, and n is an integer of 1 to 3. ) In the formula (2), the substitution position of R ₃ is an α-position carbon atom adjacent to the nitrogen atom forming the ring B, and is an azo compound represented by the following formula (3). Item 3. The azo metal chelate dye according to Item 2.

(In Formula (3), Ring A is a nitrogen-containing heteroaromatic ring which may have a substituent and may be condensed with another aromatic or aliphatic ring. Z ₁ or Z ₂ One represents a group having active hydrogen, the other represents a hydrogen atom, _one of Z ₁ or Z ₂ is a group having active hydrogen, and the other is a hydrogen atom, R ₁ and R ₂ are each independently , An alkyl group which may have a substituent or an aryl group which may have a substituent, R ₃ may have a hydrogen atom, an alkyl group which may have a substituent or a substituent. A good aryl group.)   2. The azo metal chelate dye according to claim 1, wherein the metal atom is Ni, Co, Cu or Pd. An optical recording medium having a recording layer on which information is recorded and / or reproduced by irradiated light on a substrate,
An optical recording medium, wherein the recording layer contains an azo metal chelate dye comprising an azo compound represented by the following formula (1) and a metal atom.

(In formula (1), ring A is a nitrogen-containing heteroaromatic ring which may have a substituent and may be condensed with another aromatic or aliphatic ring. Z ₁ or Z ₂ One of these is a group having active hydrogen, and the other is a hydrogen atom, and R ₁ and R ₂ are each independently an alkyl group which may have a substituent or an aryl which may have a substituent. Ring B is a ring connected by a carbon chain having 1 to 6 atoms, each R ₃ independently has a hydrogen atom, an alkyl group which may have a substituent, or a substituent. And n is an integer of 1 to 6.)

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