JP2003335061A - Optical recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording material for an optical recording medium having an enough fastness to light. <P>SOLUTION: In the optical recording medium in which an optical recording layer is formed on a substrate, the optical recording material which is used for the optical recording layer, comprises a polymethine compound consisting of an anion of formula (I) (wherein Y<SP>0</SP>is a hydrogen atom, a 1-8C alkyl group or a 6-30C aryl group) and a polymethine cation. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording material used in an optical recording medium for recording information by applying information as a thermal information pattern by a laser or the like, and more specifically, a high density optical recording by a laser or the like. And an optical recording material used for a reproducible optical recording medium.

[0002]

2. Description of the Related Art Optical recording media are widely used because they have excellent characteristics such as generally large recording capacity and non-contact recording or reproducing. In write-once optical discs such as WORM, CD-R, and DVD-R, a laser is focused on a very small area of the recording layer, recording is performed while changing the properties of the recording layer, and reproduction is performed by the difference in the reflected light amount from the unrecorded portion. It is carried out.

Since a recording layer is easy to form in the recording layer of an optical recording medium represented by an optical disk, an organic dye compound is used. Particularly, a polymethine compound has high sensitivity and corresponds to high speed. It is being considered because it can be done.

The polymethine compound is composed of a cation having a polymethine structure and an anion which is a counter ion thereof, and as the anion which is a counter ion, halogen anions such as iodine, bromine and chlorine; perchlorate anion and chloric acid. Inorganic anions such as anions, thiocyanate anions, phosphorus hexafluoride anions, antimony hexafluoride anions and boron tetrafluoride anions; organic sulfonate anions such as benzenesulfonate anion, toluenesulfonate anion and trifluoromethanesulfonate anion Etc. are used, and these are disclosed in JP 2001-20
9969, JP 2001-322354 A,
JP-A-2000-108510, JP-A-2000-1
68233, JP-A-10-235999,
It is described in JP-A-10-337959.

However, the polymethine compound using the above anion has a problem that the storage stability of the record against sunlight or natural light (hereinafter sometimes referred to as light fastness) is insufficient.

Therefore, an object of the present invention is to provide an optical recording material for an optical recording medium which has sufficient light fastness.

[0007]

As a result of repeated studies, the present inventors have found that a polymethine compound using an anion having a specific molecular structure as a counterion can solve the above-mentioned problems, and The invention was reached.

That is, the present invention is an optical recording medium in which an optical recording layer is formed on a substrate, and is used for the optical recording layer, and polymethine comprising an anion represented by the following general formula (I) and a polymethine cation. The present invention provides an optical recording material containing a compound, and an optical recording medium comprising a substrate and a thin film made of the optical recording material formed on the substrate.

[Chemical 4]

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below.

The polymethine compound according to the present invention is not particularly limited as long as the anion represented by the general formula (I) is used as a counter ion, but the polymethine cation constituting the polymethine compound is A polymethine compound represented by the following general formula (II) having a ring structure at both ends thereof is used as an optical recording material using a semiconductor laser,
It is preferable because it has optical characteristics and thermal characteristics suitable for forming recording pits.

[0011]

[Chemical 5]

In the above general formulas (I) and (II), Y ⁰
Examples of the alkyl group having 1 to 8 carbon atoms represented by are methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, isobutyl, amyl, isoamyl,
Examples include tertiary amyl, hexyl, cyclohexyl, cyclohexylmethyl, 2-cyclohexylethyl, heptyl, isoheptyl, tertiary heptyl, 3-heptyl, n-octyl, isooctyl, tertiary octyl and 2-ethylhexyl, having 6 to 30 carbon atoms. Examples of the aryl group include phenyl, naphthyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4-vinylphenyl, 3
-Isopropylphenyl, 4-isopropylphenyl,
4-butylphenyl, 4-isobutylphenyl, 4-tertiary butylphenyl, 4-hexylphenyl, 4-cyclohexylphenyl, 4-octylphenyl, 4- (2-
Ethylhexyl) phenyl, 4-stearylphenyl,
2,3-dimethylphenyl, 2,4-dimethylphenyl, 2,5-dimethylphenyl, 2,6-dimethylphenyl, 3,4-dimethylphenyl, 3,5-dimethylphenyl, 2,4-di-tert-butyl Phenyl, 2,5-di-tert-butylphenyl, 2,6-di-tert-butylphenyl,
2,4-ditertiary pentylphenyl, 2,5-ditertiary amylphenyl, 2,5-ditertiary octylphenyl, 2,4
-Dicumylphenyl, cyclohexylphenyl, biphenyl, 2,4,5-trimethylphenyl.

In the above general formula (II), R ¹ and R ¹ '
Examples of the halogen atom represented by are fluorine, chlorine, bromine and iodine, and examples of the aryl group having 6 to 30 carbon atoms and the alkyl group having 1 to 8 carbon atoms include those exemplified as Y ⁰ above. Examples of the alkoxy group having 1 to 8 carbon atoms include methyloxy, ethyloxy, isopropyloxy, propyloxy, butyloxy, pentyloxy, isopentyloxy, hexyloxy, heptyloxy, octyloxy and 2-ethylhexyloxy. Examples of the halogen atom, the aryl group having 6 to 30 carbon atoms and the alkyl group having 1 to 8 carbon atoms represented by R ² and R ² ′ include those exemplified as the above R ¹ .
Further, examples of the halogen atom represented by R ^{3 to} R ⁹ and R ³ ′ to R ⁹ ′ and the alkyl group represented by C 1 to 8 include those exemplified as the above R ¹ , and the adjacent substituent Examples of the group forming a condensed ring with the group include aromatic rings such as benzene, naphthalene, chlorobenzene, bromobenzene, methylbenzene, ethylbenzene, methoxybenzene, and ethoxybenzene; furan ring, benzofuran ring, pyrrole ring, thiophene ring, pyridine ring. And heterocycles such as quinoline ring and thiazole ring; and aliphatic rings such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane and cyclooctane.

Cycloalkane-1,1-diyl having 3 to 6 carbon atoms represented by X and X'include cyclopropane-1,1-diyl, cyclobutane-1,1-diyl,
2,4-dimethylcyclobutane-1,1-diyl, 3-
Examples thereof include dimethylcyclobutane-1,1-diyl, cyclopentane-1,1-diyl and cyclohexane-1,1-diyl.

1 to 3 carbon atoms represented by Y, Y'and Y ^2.
Examples of the organic group of 0 include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, isobutyl, amyl, isoamyl, tert-amyl, hexyl, cyclohexyl, cyclohexylmethyl, 2-cyclohexylethyl, heptyl and isoheptyl. , Third heptyl, n
-Alkyl groups such as octyl, isooctyl, tertiary octyl, 2-ethylhexyl, nonyl, isononyl, decyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, peptadecyl, octadecyl, vinyl, 1-methylethenyl, 2-methylethenyl, propenyl, butenyl. , Alkenyl groups such as isobutenyl, pentenyl, hexenyl, heptenyl, octenyl, decenyl, pentadecenyl, 1-phenylpropen-3-yl, phenyl, naphthyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 4- Vinylphenyl, 3-isopropylphenyl, 4-isopropylphenyl, 4-butylphenyl, 4-isobutylphenyl,
4-tert-butylphenyl, 4-hexylphenyl, 4-
Cyclohexylphenyl, 4-octylphenyl, 4-
(2-Ethylhexyl) phenyl, 4-stearylphenyl, 2,3-dimethylphenyl, 2,4-dimethylphenyl, 2,5-dimethylphenyl, 2,6-dimethylphenyl, 3,4-dimethylphenyl, 3,5 -Alkylaryl groups such as dimethylphenyl, 2,4-di-tert-butylphenyl and cyclohexylphenyl, arylalkyl groups such as benzyl, phenethyl, 2-phenylpropan-2-yl, diphenylmethyl, triphenylmethyl, styryl and cinnamyl. Etc., those interrupted by an ether bond or a thioether bond, for example, 2-methoxyethyl, 3-methoxypropyl, 4-methoxybutyl, 2-butoxyethyl, methoxyethoxyethyl, methoxyethoxyethoxyethyl, 3-methoxybutyl. ,
2-phenoxyethyl, 3-phenoxypropyl, 2-
Examples thereof include methylthioethyl and 2-phenylthioethyl, and these groups include an alkoxy group, an alkenyl group,
It may be substituted with a nitro group, a cyano group, a halogen atom or the like.

The polymethine compound according to the present invention includes
In the above general formula (II), the ring A is represented by (a) or (d), and the ring A ′ is represented by (a ′) or (d ′) because of its high sensitivity, and ring A is preferable. Is represented by (a),
More preferred is ring A ′ represented by (a ′),
X in (a) and X'in (a ') are each independently propane-2,2-diyl, butane-2,2-diyl, 3
More preferred is -phenylpropane-1,1-diyl or cyclohexane-1,1-diyl.

In the polymethine compound according to the present invention, the linking group Q in the above general formula (II) is appropriately selected according to the wavelength of the semiconductor laser used.
For example, when a laser of 750 to 830 nm typified by CD-R is used, a heptamethine chain or a pentamethine chain is selected, and when a laser of 630 to 670 nm typified by DVD-R is used, pentamethine is used. Those constituting a chain or trimethine chain are selected, and these may include a ring structure in the polymethine chain.

The linking group Q is preferably a group represented by any of the following groups III (1) to (6).

[0019]

[Chemical 6]

In the above-mentioned group III (1) to (6), R
Examples of the aryl group having 6 to 30 carbon atoms and the alkyl group having 1 to 8 carbon atoms represented by ¹⁰ and R ¹¹ include those exemplified above for R ¹ and having 6 to 30 carbon atoms represented by Z. The same applies to the aryl group and the alkyl group having 1 to 8 carbon atoms.

Of the above-mentioned group III, the group represented by (1) or (2) is particularly preferable as the above-mentioned linking group Q because of its large extinction coefficient.

Specific examples of the polymethine cation moiety in the above general formula (II) include the following compound No. 1-61
Is mentioned.

[0023]

[Chemical 7]

[0024]

[Chemical 8]

[0025]

[Chemical 9]

[0026]

[Chemical 10]

[0027]

[Chemical 11]

The polymethine compound according to the present invention is not limited by its production method. Further, the polymethine compound according to the present invention represented by the general formula (II) is not limited by the production method,
It can be manufactured according to a conventionally known method. For example, after reacting a cyclic compound having a ring structure and a bridging agent compound for introducing a linking group chain with a reaction agent,
It can be synthesized by anion exchange. More specifically, in the case where the ring A and the ring A ′ are (a) and (a ′), respectively, and the linking group Q is (1) or (2), which is a preferred embodiment of the present invention, Synthesized by the route, ring A and ring A'are (d) and (d ') respectively,
When the linking group Q is (1) or (2), it can be synthesized by the following route.

[0029]

[Chemical 12]

The optical recording material of the present invention containing the above polymethine compound is applied as an optical recording layer of an optical recording medium, but the method for forming the optical recording layer is not particularly limited. Generally, lower alcohols such as methanol and ethanol; ether alcohols such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, and butyldiglycol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol, ethyl acetate, Esters such as butyl acetate and methoxyethyl acetate; acrylic acid esters such as ethyl acrylate and butyl acrylate, 2,2,3,3-
Fluorinated alcohols such as tetrafluoropropanol;
Hydrocarbons such as benzene, toluene, xylene; a solution of the polymethine compound according to the present invention dissolved in an organic solvent such as chlorinated hydrocarbons such as methylene dichloride, dichloroethane, chloroform, etc. on a substrate by spin coating, spraying, dipping A wet coating method is used in which coating is performed by using the above method. Other methods include vapor deposition and sputtering.

The thickness of the above optical recording layer is usually 0.00
It is 1 to 10 μm, preferably 0.01 to 5 μm.

The amount of the optical recording material of the present invention used in the optical recording layer of the optical recording medium is preferably 50 to 50.
It is 100% by mass.

The above-mentioned optical recording layer may be a cyanine compound, an azo compound, a phthalocyanine compound, etc., if necessary, in addition to the optical recording material of the present invention. Compounds other than polymethine compounds; resins such as polyethylene, polyester, polystyrene, polycarbonate; surfactants; antistatic agents; lubricants; flame retardants; radical scavengers such as hindered amines; pit formation accelerators such as ferrocene derivatives; dispersants; An antioxidant, a cross-linking agent, a light resistance imparting agent and the like may be contained.

Further, the optical recording layer has an aromatic nitroso compound, an aminium compound, an iminium compound, a bisiminium compound, as a quencher for singlet oxygen and the like.
It may contain a transition metal chelate compound or the like, and may contain a quencher anion. These are preferably used in the range of 0 to 50% by mass in the optical recording layer.

The quencher described above is disclosed in JP-A-5-104.
861 gazette, JP-A-5-294070, JP-A-6-199045, JP-A-11-277904, JP-A-2000-177248 and the like, and for example, the following general formula (A) What is represented by.

[0036]

[Chemical 13]

In the above general formula (A), the anion represented by An ^n- is, for example, a monovalent halogen anion such as chlorine anion, bromine anion, iodine anion and fluorine anion; perchlorate anion. Inorganic anions such as chlorate anion, thiocyanate anion, phosphorus hexafluoride anion, antimony hexafluoride anion and boron tetrafluoride anion; benzenesulfonate anion, toluenesulfonate anion, trifluoromethanesulfonate anion, etc. Sulfonate anion; Octylphosphate anion, Dodecylphosphate anion, Octadecylphosphate anion, Phenylphosphate anion, Nonylphenylphosphate anion, 2,2'-Methylenebis (4,6-ditertiarybutylphenyl) phosphonate anion, etc. Organic phosphoric acid-based ani Examples thereof include ON and the like, and divalent ones include benzenedisulfonic acid anion and naphthalenedisulfonic acid anion.

Specific examples of the above quencher include the following quencher No. 1-3. In addition, the following quencher-No. 1 to 3 are represented by cations without anions.

[0039]

[Chemical 14]

Further, the quencher anion is disclosed in Japanese Patent Laid-Open No.
0-234892, JP-A-5-579, JP-A-5-43814, JP-A-6-239028, JP-A-9-309886, and JP-A-10-4.
5767, JP-A No. 11-227331 and the like, and examples thereof include those represented by the following general formula (B) or (C).

[0041]

[Chemical 15]

Specific examples of the quencher anion include the following anion No. 1-24 are mentioned.

[0043]

[Chemical 16]

[0044]

[Chemical 17]

[0045]

[Chemical 18]

The materials of the above-mentioned substrate on which the optical recording layer according to the present invention is provided are write (recording) light and read (reproduction).
There is no particular limitation as long as it is substantially transparent to light, and for example, resins such as polymethyl methacrylate, polyethylene terephthalate, and polycarbonate, glass, and the like are used. Further, the shape thereof may be an arbitrary shape such as a tape, a drum, a belt or a disk, depending on the application.

A reflection film can be formed on the above optical recording layer by vapor deposition or sputtering using gold, silver, aluminum, copper or the like, or a protective layer made of acrylic resin, ultraviolet curable resin or the like. Can also be formed.

The optical recording material of the present invention is suitable for an optical recording layer of an optical recording medium which uses a semiconductor laser for recording and reproduction, and is particularly suitable for an optical recording layer of an optical disk such as CD-R and DVD-R. .

[0049]

EXAMPLES The present invention will be described in more detail with reference to production examples, examples, comparative examples and evaluation examples. However, the present invention is not limited to the following examples.

[Production Example 1] Compound No. Preparation of Diphenylamine-4-sulfonate of No. 6 7.81 g of N-methylnitroindolenine toluenesulfonate, 1.96 g of diphenylformamidine, 15.8 g of pyridine, and 3.06 g of acetic anhydride were charged into a reaction flask substituted with nitrogen. The mixture was stirred under a nitrogen stream at 25 ° C for 3 hours. Chloroform 50 ml, diphenylamine-
After adding 8.14 g of sodium 4-sulfonate and 50 ml of water and stirring for 30 minutes, the chloroform phase was separated. This was washed with water and then desolvated to obtain a residue, which was recrystallized from methanol to obtain 4.52 g of crystals (yield 65.0%). The following analysis was performed on this, and the structure and the like were confirmed. The analysis results are shown below. (Analysis result) Purity: HPLC measurement; 99.5% Structural analysis: ¹ H-NMR measurement (chemical shift ppm; multiplicity; number of protons) (1.75; s; 12) (3.71; s; 6) (6.6
3 to 6.72; d; 2) (6.79 to 6.84; t;
1) (6.95 to 6.97; d; 2) (7.07 to 7.
08; d; 2) (7.20 to 7.24; t; 2) (7.
40-7.45; d; 2) (7.67-7.70; d;
2) (8.23; s; 1) (8.37-8.45; m;
3) (8.57; s; 2) Optical characteristics: UV spectrum measurement in methanol solvent λmax; 562 nm, ε; 1.95 × 10 ⁵ Thermal decomposition start temperature: In nitrogen stream, at 10 ° C./minute temperature rise Differential thermal analysis of 269 ℃

[Production Example 2] Compound No. Preparation of 31 Diphenylamine-4-Sulfonate N-isoamylbenzoindolenintoluenesulfonate 9.03 g, malondialdehyde dianiline hydrochloride 2.596 g, pyridine 1 in a nitrogen-substituted reaction flask.
Charge 5.8g and acetic anhydride 3.06g, under nitrogen stream 2
The mixture was stirred at 5 ° C for 3 hours. 50 ml of chloroform,
Sodium diphenylamine-4-sulfonate 8.14
After adding g and 50 ml of water and stirring for 30 minutes, the chloroform phase was separated. This was washed with water and desolvated, and the obtained residue was recrystallized from methanol to obtain 5.99 g of crystals (yield 71.0%). The following analysis is done about this,
The structure etc. were confirmed. The analysis results are shown below. (Analysis result) Purity: HPLC measurement; 99.6% Structural analysis: ¹ H-NMR measurement (chemical shift ppm; multiplicity; number of protons) (0.95 to 1.01; d; 12) (1.57 to 1.6
3; q; 4) (1.73 to 1.84; m; 2) (1.9
5; s; 12) (4.18 to 4.23; t; 4) (6.
31-6.35; d; 2) (6.62-6.69; t;
1) (6.79 to 6.83; t; 1) (6.91 to 6.
99; d; 2) (7.02 to 7.07; d; 2) (7.
17-7.24; t; 2) (7.39-7.45; d;
2) (7.47 to 7.53; t; 2) (7.65 to 7.
74; m; 4) (8.00-8.10; t; 4) (8.
20-8.26; s + s; 3) (8.43-8.50;
t; 2) Optical properties: UV spectrum measurement in methanol solvent λmax; 680 nm, ε; 2.30 × 10 ⁵ Thermal decomposition start temperature: Differential thermal analysis at a temperature rise of 10 ° C./min in a nitrogen stream 248 ° C.

[Production Example 3] Compound No. Synthesis of diphenylamine-4-sulfonate of 7 N-methylnitroindolenine toluenesulfonic acid
The target product was synthesized in the same manner as in Production Example 1 above, except that-[2- (4-isopropoxyphenyl) ethyl] nitroindolenine toluenesulfonic acid was used.
The analysis results are shown below. (Analysis result) Purity: HPLC measurement; 99.7% Structural analysis: ¹ H-NMR measurement (chemical shift ppm; multiplicity; number of protons) (1.06-1.10; d; 12) (1.67; s; 1
2) (3.01 to 3.05; t; 4) (4.42 to 4.
49; m; 6) (6.43 to 6.47; d; 2) (6.
73-6.77; d; 4) (6.79-6.84; t;
1) (6.94 to 6.97; d; 2) (7.05 to 7.
08; d; 2) (7.17 to 7.18; d; 4) (7.
20-7.24; t; 2) (7.41-7.44; d;
2) (7.52 to 7.55; d; 2) (8.18 to 8.
31; m; 4) (8.56; s; 2) Optical properties: UV spectrum measurement in methanol solvent λmax; 573 nm, ε; 1.76 × 10 ⁵ Thermal decomposition start temperature: 10 ° C./in nitrogen stream Differential thermal analysis at minute temperature rise 271 ℃

[Production Example 4] Compound No. Synthesis of 36 diphenylamine-4-sulfonate 2-naphthylhydrazine 3 in a reaction flask purged with nitrogen.
Charge 0.1 g and ethanol 94.8 g and warm to 70 ° C., then add 58.0 g of acetylcyclohexane.
Dropped in minutes. After further adding 39.2 g of sulfuric acid and reacting for 3 hours, ethanol was distilled off, and 500 ml of toluene was added to 2 ml.
200 g of 0 mass% sodium hydroxide aqueous solution was added, and oily water was separated. The oil phase was washed with water until the washing water became neutral, dried over sodium sulfate and desolvated, and the residue obtained was dissolved in 94 g of toluene at 60 ° C. To a solution dissolved in 94 g of N-hexane, crystallization was performed. , The crystals are collected by filtration and dried to give the intermediate (A)
27.2g was obtained. 25.0 g of the intermediate (A) and 17.1 g of methyl iodide were charged into a reaction flask purged with nitrogen, and the mixture was reacted at 110 ° C. for 4 hours, and then ethyl acetate 10 was added.
2.4 g was added dropwise and the mixture was refluxed for 30 minutes and cooled. The solid phase was collected by filtration, washed and dried to obtain 27.2 g of intermediate (B). Intermediate product (B) 11.8 was added to a reaction flask purged with nitrogen.
g, and 23.7 g of pyridine were added and heated to 50 ° C., a solution prepared by dissolving 5.00 g of the following raw material compound in 3.1 g of acetic anhydride was added dropwise over 30 minutes, and then reacted at 70 ° C. for 2 hours. . To this system, 5.10 g of sodium diphenylamine-4-sulfonate and 35.6 g of methanol were added, and 1
Reflux for hours. After cooling the reaction system, the precipitated crystals are washed with methanol and water and then dried to obtain the desired crystal 2.
84 g (yield 35.3%) was obtained. The following analysis was performed on this, and the structure and the like were confirmed. The analysis results are shown below. (Analysis result) Purity: HPLC measurement; 99.6% Structural analysis: ¹ H-NMR measurement (chemical shift ppm; multiplicity; number of protons) (1.73 to 1.92; m; 6) (1.95; s; 6)
(1.99 to 2.08; m; 2) (2.45 to 2.5
8; m; 2) (3.69; s; 3) (3.96; s;
3) (6.27-6.32; d; 1) (6.58-6.
63; d; 1) (6.69 to 6.76; t; 1) (6.
79-6.84; t; 1) (6.91-6.97; d;
2) (7.05-7.11; d; 2) (7.19-7.
24; t; 2) (7.39 to 7.45; d; 2) (7.
46-7.53; q; 2) (7.62-7.69; q;
2) (7.71-7.75; d; 1) (7.78-7.
82; d; 1) (8.02 to 8.11; m; 4) (8.
21-8.33; m; 5) Optical characteristics: UV spectrum measurement in methanol solvent λmax; 678 nm, ε; 1.98 × 10 ⁵ Thermal decomposition start temperature: In nitrogen stream, at 10 ° C./min temperature increase Differential thermal analysis 222 ° C

[0054]

[Chemical 19]

Examples 1 to 6 Production of Optical Recording Medium and Evaluation of Appropriate Recording Light Wavelength A titanium chelate compound (T-50: manufactured by Nippon Soda Co., Ltd.) was applied and hydrolyzed to form a base layer (0.01 μm). Compound No. was placed on a polycarbonate disk substrate having a diameter of 12 cm. A 2,2,3,3-tetrafluoropropanol solution of 4,6,7,22,31 or 36 of diphenylamine-4-sulfonate (concentration 2.0% by mass) is applied by spin coating, An optical recording layer having a thickness of 100 nm was formed to obtain an optical recording medium. Regarding these optical recording media, the UV spectrum absorption was measured for the wavelength of the recording light currently used in the optical recording disk, and the appropriate recording light wavelength was evaluated. When the intensity of λmax of each optical recording medium is 1, and the relative intensity to this is less than 0.15, the recording and reproducing characteristics deteriorate,
If it exceeds 0.50, the light resistance of the recording layer is deteriorated and the storage stability of the recording is deteriorated. Therefore, the appropriate recording light wavelength is one in which the relative intensity is within a suitable range of 0.15 to 0.50. The results are shown in Table 1.

[0056]

[Table 1]

[Evaluation Example 1 and Comparative Evaluation Example 1] Evaluation of light resistance A titanium chelate compound (T-50: manufactured by Nippon Soda Co., Ltd.) was coated and hydrolyzed to provide a base layer (0.01 μm) with a diameter of 12 cm. A 2,2,3,3-tetrafluoropropanol solution (concentration 2.0% by mass) of the polymethine compound shown in Table 2 was applied onto a disk substrate by spin coating to give an optical recording layer having a thickness of 100 nm. (Thin film) was formed to obtain an optical recording medium. These optical recording media were irradiated with light of 55000 lux for 20 hours using a xenon weather resistance tester (Table Sun: manufactured by Suga Test Instruments Co., Ltd.), and the absorbance at the λ _max of the thin film immediately after coating was formed. Ratio of A'and absorbance A after irradiation A /
The light resistance was evaluated using A '(%) as the residual ratio of the dye. The results are shown in Table 2.

[0058]

[Table 2]

[Evaluation Example 2 and Comparative Evaluation Example 2] Evaluation of light resistance A tetrafluoropropanol solution (total concentration: 1.5% by mass) was prepared according to the formulations shown in Tables 3 and 4 below.
An optical recording medium was manufactured in the same manner as in Evaluation Example 1 above, and light resistance was evaluated. The results are shown in Tables 3 and 4. The quencher Nos. In Tables 3 and 4 were used. As the anion of 3, antimony hexafluoride was used.

[0060]

[Table 3]

[0061]

[Table 4]

[0062]

INDUSTRIAL APPLICABILITY The present invention can provide an optical recording material for an optical recording medium having sufficient light fastness.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Mitsuhiro Okada             7-35 Higashiokyu, Arakawa-ku, Tokyo Asahiden             Chemical Industry Co., Ltd. (72) Inventor Yuki Fushimi             7-35 Higashiokyu, Arakawa-ku, Tokyo Asahiden             Chemical Industry Co., Ltd. F-term (reference) 2H111 EA03 EA12 EA22 EA25 EA39                       FB42                 4H056 CA01 CC02 CC08 CE03 DD03                       FA06                 5D029 JA04 JC17

Claims (6)

[Claims] 1. An optical recording medium having an optical recording layer formed on a substrate, which contains a polymethine compound used for the optical recording layer and comprising an anion represented by the following general formula (I) and a polymethine cation. Optical recording material consisting of [Chemical 1] 2. The polymethine compound represented by the following general formula (I
The optical recording material according to claim 1, which is represented by I). [Chemical 2] 3. The linking group Q (1) to (3) of the following group III:
The optical recording material according to claim 2, which is a group represented by any one of (6). [Chemical 3] 4. The ring A is a group represented by the above (a) or (d), and the above ring A ′ is the above (a ′) or (d ′).
The optical recording material according to claim 2, which is a group represented by: 5. The optical recording material according to claim 3, wherein the linking group Q is a group represented by the above (1) or (2). 6. An optical recording medium, wherein a thin film made of the optical recording material according to any one of claims 1 to 5 is formed on a substrate.