JPH0248992A - Optical recording medium comprising imidazole dye - Google Patents

Abstract

PURPOSE:To enhance reflectance and contrast and improve preservation stability by providing a recording layer comprising an imidazole dye of a specified general formula on a base to produce an optical recording medium. CONSTITUTION:An imidazole dye of formula I (each of R1 and R2 is hydrogen or an alkyl, each of R3, R4, R5, and R6 is hydrogen, a halogen, alkyl, alkoxyl or amino, and each of A and B is an organic group linked to the imidazole ring through a carbon, nitrogen, oxygen or sulfur atom), a binder and the like are dissolved in an organic solvent to prepare a coating liquid. The coating liquid is applied to a base, followed by drying to provide an information recording layer, thereby producing an optical recording material. The thickness of the information recording layer is ordinarily 100Angstrom to 5mum, preferably 1,000Angstrom to 3mum.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical recording material using a laser, and more specifically to an optical recording material using an imidazole dye as a recording medium for laser light. .

BACKGROUND OF THE INVENTION In recent years, optical recording using lasers has been actively researched and developed because it enables recording, storage, and reproduction of high-density information.

An example of optical recording is an optical disc.

In general, optical discs record high-density information by irradiating a thin recording layer provided on a circular base with laser light focused to about 1 μm. The recording is performed when the recording layer absorbs the energy of the irradiated laser beam and undergoes changes such as decomposition, evaporation, sublimation, and dissolution.

Further, the reproduction of recorded information is performed by irradiating the recording layer with laser light to an extent that does not cause any change, and reading the difference in reflectance between a portion of the recording layer that has been changed and a portion that has not.

Therefore, as an optical recording material, it is necessary to efficiently absorb the energy of laser light, so it must have a high absorption of laser light of a specific wavelength used for recording.
In order to accurately reproduce information, it is necessary to have a high reflectance for laser light of a specific wavelength used for reproduction.

Various optical recording materials of this type are known. For example, Japanese Patent Laid-Open No. 55-97033 discloses one in which a single layer of phthalocyanine dye is provided on a substrate. However, since phthalocyanine dyes have low sensitivity to laser light and low solubility in organic solvents, they also have the problem that they cannot be coated by coating.

Further, JP-A-58-83344 discloses a recording layer in which a naphthoquinone dye is provided. However, although such dyes have the advantage of being easy to vapor-deposit, they have low reflectance, and the contrast related to the reflectance between areas recorded by laser light and unrecorded areas is low (and the recorded information is Regeneration becomes difficult.Furthermore, organic dyes generally have a problem of poor storage stability.

Therefore, the inventors of the present invention continued various studies in order to search for dyes that have good properties against laser light, and as a result, among many dyes, they found the dyes suitable for laser light recording.
They discovered imidazole dyes and accomplished the present invention.

OBJECTS OF THE INVENTION The objects of the present invention are to have high solubility in organic solvents, to be able to be coated by coating, and to have high reflectance.
An object of the present invention is to provide an optical recording material containing an imidazole dye, which has good contrast and excellent storage stability.

Structure of the Invention Accordingly, the above object of the present invention has been achieved by an optical recording material having an imidazole dye represented by the general formula (1).

General formula (1) [wherein R1 and R2 each represent a hydrogen atom, an alkyl group, or a substituted alkyl group, and R+ and R2 may be bonded to each other to form a 5-membered ring or a 6-membered ring.

R, , R, , R, and R4 are each a hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl group, an alkoxy group,
Represents a substituted alkoxy group, amino group or substituted amino group.

A and B represent an organic group bonded to the imidazole ring via a carbon atom, nitrogen atom, oxygen atom or sulfur atom. ] Further, the object of the present invention is to provide an optical recording material comprising a recording layer and a substrate in which recording is performed by changing the state with a laser beam, wherein the recording layer has a compound represented by the general formula [r]. This was achieved using an optical recording material containing an imidazole dye.

The present invention will be explained in more detail below.

In the imidazole dye represented by general formula (1),
R5 and R2 are preferably hydrogen atoms, alkyl groups, and substituted alkyl groups such as hydroxyalkyl groups, alkoxyalkyl groups, alkoxyalkoxyalkyl groups, and alkylsulfonamidoalkyl groups. Examples of these groups include alkyl groups having 1 to 18 carbon atoms such as methyl, ethyl, propyl, isopropyl, 5ec-butyl, butyl, isobutyl, t-butyl, octyl, dodecyl, octadecyl, cyclohexyl, hydroxyethyl, Methoxyethyl, methoxybutyl, ethoxyethyl, methoxyethoxyethyl, ethoxyethoxyethyl,
Examples include substituted alkyl groups such as β-methanesulfonamidoedyl.

Examples of the 5-membered ring or 6-membered ring formed by combining R1 and R2 include groups such as pyrrolidino, piperidino, piperazino, and morpholino.

R3, R,, Rs and R6 may be the same or different, preferably a hydrogen atom, a halogen atom, an alkyl group, a hydroxyalkyl group, an alkoxyalkyl group, an alkylsulfonamidoalkyl group, an alkoxy group,
These include an amino group, an alkyl-substituted amino group, a dialkyl-substituted amine group, and an alkyl-substituted amino group. Examples of these include chlorine atom, bromine atom, methyl, ethyl, hydroxymethyl, hydroxyethyl, methoxyethyl, methanesulfonamidoethyl, methoxy, ethoxy, N-methylamino, N,N-diethylamino, sulfonamino,
Examples include groups such as acetylamino.

A is an organic group bonded to the imidazole ring via a carbon atom, nitrogen atom, oxygen atom or sulfur atom, and these A
and B may be the same or different.

Organic groups via carbon atoms include alkyl groups (for example, methyl, i-propyl, t-butyl, trifluoromethyl, benzyl, 3-(4-aminophenyl)propyl, allyl, 2-dodecyloxyethyl, 3 -phenoxypropyl, 2-hexylsulfonylethyl, 3- (4
-(4-dodecyloxybenzene)sulfonamidophenyl]propyl, l-methyl-2-[(2-octyloxy-5-t-octylphenyl)sulfonamidophenyl]ethyl, 1-methyl-2=[2-octyl Oxy-5-(2-octyloxy-5-toctylphenylsulfonamide) phenylsulfonamide]ethyl, 2
-[2-octyloxy-5-(2-octyloxy-
5-t-octylphenylsulfonamide) phenylsulfonamide] ethyl, etc.).

An aryl group (for example, a phenyl group, a naphthyl group, a substituted phenyl group, a substituted naphthyl group is preferable; examples of the substituent include a halogen atom (preferably fluorine, chlorine, bromine), a cyano group, a nitro group, a carboxyl group, respectively). an optionally substituted alkyl group, alkoxy group, alkylamido group, arylamide group, alkylsulfonamide group, arylsulfonamide group, carbamoyl group,
Sulfamoyl group, dialkylcarbamoylamino group,
Dialkylsulfamoylamino group; each optionally substituted arylcarbamoylamino group, alkyloxycarbonylamino group, imide group, alkylcarbamoyl group, alkylsulfamoyl group, arylcarbamoyl group, arylsulfamoyl group, alkoxycarbonyl group, alkoxysulfonyl group, and the like.

To explain each of these substituents in more detail, examples of unsubstituted alkyl groups include methyl, ethyl, 5ec
Straight-chain or branched alkyl groups having 1 to 22 carbon atoms, such as -butyl, t-octyl, dodecyl, etc., are preferred, and substituted alkyl groups include hydroxy-substituted alkyl groups, such as tehahydroxydiethyl, methoxyethyl,
An alkoxy-substituted alkyl group represented by a methoxyethoxyethyl group is preferred.

Examples of unsubstituted alkoxy groups include methoxy, ethoxy, n-butoxy, 5ec-butoxy, dodecyloxy, octadecyloxy, etc.
A linear or branched alkoxy group of 22 is preferred, and the substituted alkoxy group is preferably an alkoxy-substituted alkoxy group typified by methoxyethoxy and the like.

The unsubstituted alkylamide group is preferably an amide group of an alkane having 1 to 22 carbon atoms such as acetamide, propionamide, pentanamide, laurylamide, stearylamide, etc., and the substituted alkylamide group is preferably 2.4- di-t-amylphenoxyacetamide,
Preferred are phenoxy-substituted alkylamide groups such as 2-(m-pentadecylphenoxy)butanamide, and halogen-substituted alkylamide groups such as chloroacetamide, trifluoroacetamide, and perfluorobutanamide.

Examples of the ori-ruamide group include unsubstituted ori-ruamide groups such as benzamide and naphthamide, alkoxy-substituted benzamide groups such as 0-tetradecaoxybenzamide, traurylamide benzamide, and ta-(2-
Amide- and sulfonamide-substituted benzamides such as (2,4-di-t-amylphenoxy)hexaneamide)benzamide, 0-hexadecanesulfonamide benzamide, and 0. Preferred are halogen-substituted benzamide groups such as chlorobenzamide and perfluorobenzamide.

The alkylsulfonamide group has 1 carbon atom and is represented by methanesulfonamide, ethanesulfonamide, butanesulfonamide, hexadecanesulfonamide, etc.
-22 alkane sulfonamide groups are preferred.

Examples of arylsulfonamides include unsubstituted arylamide groups such as benzenesulfonamide and naphthalenesulfonamide, and p-)luenesulfonamide, xylenesulfonamide, dodecylbenzenesulfonamide, p-dodecyloxybenzenesulfonamide, etc. Preferred examples of the substituted benzenesulfonamide group include an alkyl-substituted benzenesulfonamide group and an alkoxy-substituted benzenesulfonamide group.

Further, as the alkyl group of the dialkylcarbamoylamino group and the dialkylsulfamoylamino group, an alkyl group having 1 to 8 carbon atoms is preferable, and methyl, ethyl, propyl, and butyl each having 1 to 4 carbon atoms are representative and preferable. .

In addition, as the arylcarbamoylamino group, unsubstituted phenylcarbamoylamino group of phenylcarbamoylamino group, p-cyanophenylcarbamoylamino group, and p-cyanophenylcarbamoylamino group
A halogen-substituted phenylcarbamoyl group represented by -chlorophenylcarbamoylamino is preferable as the substituted phenylcarbamoyl group.

The alkyl of the alkyloxycarbonylamino group has 1 to 1 carbon atoms, such as methyl, ethyl, butyl, dodecyl, etc.
An unsubstituted alkyl group of 22 is preferable, and the imide group is preferably succinimide, phthalimide, or an alkyl substituted product thereof.

The alkyl of the alkylcarbamoyl group and alkylsulfamoyl group has 1 to 2 carbon atoms, such as butyl, dodecyl, etc.
Alkylcarbamoyl groups and alkylsulfamoyl groups with unsubstituted alkyl groups such as the alkyl group in 2, and γ
- Substituted alkylcarbamoyl group or substituted alkylsulfamoyl group having a phenoxy-substituted alkyl group such as -(2,4-di-t-amylphenoxy)butyl, an alkoxy-substituted alkyl group such as n-dodecyloxypropyl, etc. is preferred.

Arylcarbamoyl and arylsulfamoyl groups include unsubstituted arylcarbamoyl groups such as phenylcarbamoyl and phenylsulfamoyl, unsubstituted arylsulfamoyl groups, phenylcarbamoyl groups and phenylsulfamoyl substituted with alkyl groups and halogen atoms. A substituted phenylcarbamoyl group and a substituted phenylsulfamoyl group represented by the following groups are preferred.

The alkoxy group of the alkoxycarbonyl group and alkoxysulfonyl group, each of which may be substituted, is preferably an unsubstituted alkoxy group having 1 to 22 carbon atoms, represented by methoxy, ethoxy, butoxy, and the like.

), heterocyclic groups (e.g., 4-pyridyl, 2-benzimidazolyl, etc.), cyano groups, carboxyl groups, acyl groups,
Examples include carbamoyl group, alkoxycarbonyl group, and aryloxycarbonyl group.

Examples of organic groups via a nitrogen atom include acylamino groups (e.g., acetamide, benzamide, 2゜4-di-t-
amylphenoxyacetamide, 2,4-dichlorobenzamide, etc.), alkoxycarbonylamino groups (e.g., methoxycarbonylamino, propoxycarbonylamino, t-butoxycarbonylamino, etc.), aryloxyluponylamino groups (e.g., phenoxycarbonylamino), sulfone Amide groups (e.g., methanesulfonamide, octanesulfonamide, benzenesulfonamide, 4-dodecyloxybenzenesulfonamide, etc.), anilino groups (e.g., phenylamino, 2-chloroanilino, 2-chloro-4-tetradecanamideanilino, etc.) ), ureido groups (e.g., N-methylureido, N
-butylureido, N-phenylureido, N,N-dibutylureido, etc.), sulfamoylamino groups (e.g., N,N-diethylsulfamoylamino, N-phenylsulfamoylamino, etc.), amino groups (e.g. , unsubstituted amino, N-methylamino, N,N-diethylamino, etc.), heterocyclic groups (for example, 3.5-dimethyl-1-pyrazolyl, 2.6-dimethylmorpholino group), and the like.

Examples of organic groups via an oxygen atom include alkoxy groups (e.g., methoxy, ethoxy, i-propoxy, butoxy,
2.2.2-trifluoroethoxy, 3.3.3-trifluoropropoxy, 2-chloroethoxy, 2-cyanoethoxy, 2-butanesulfonylethoxy, etc.), aryloxy groups (e.g., phenoxy, 4-methoxyphenoxy) , 2,4-dichlorophenoxy, 4-(2-ethylhexaneamido)phenoxy, etc.), silyloxy groups (e.g., trimethylsilyloxy, dimethylphenylsilyloxy, dimethyl-t-butylsilyloxy, etc.), heterocyclic oxy groups (e.g. , tetrahydropyranyloxy,
3-pyridyloxy, 2-(1,3-benzimidazolyl)oxy, etc.).

Examples of organic groups via a sulfur atom include alkylthio groups (for example, methylthio, ethylthio, butylthio, 3-(4
-aminophenyl)propylthio, hexadecylthio,
Benzylthio, 4-aminobenzylthio, 3- (4-
(4-dodecyloxybenzene)sulfonamidophenyl]propylthio, 4-(2-butoxy-5-t-octylphenylsulfonamido)benzylthio, etc.), arylthio, etc. (e.g., phenylthio, 2-naphthylthio, 2.5-dichlorophenylthio) , 4-dodecylphenylthio, 2-butoxy-5-t-octylphenylthio, etc.), heterocyclic thio groups (e.g. 5,2-pyridylthio, 2-butoxy-5-t-octylphenylthio, etc.),
-(1,3-benzoxasilyl)thio group, ■-hexadecyl-1.2.3.4-tetrazolyl-5-thio group,
1-(3-N-octadecylcarbamoyl)phenyl-
1,2,3,4-tetrazolyl-5thio, etc.).

The imidazole dye represented by the general formula (1) used as the optical recording medium used in the present invention is 600n
It has absorption in the wavelength band of m to 800 nm, and has a molar absorption coefficient of 104 to 105.

Next, typical compounds of imidazole dyes used in the present invention are illustrated, but the present invention is not limited to these compounds.

Imidazole dye NHCo CHx The imidazole dye represented by the general formula (1) is a compound represented by the following general formula (II) and the following general formula (fi
It can be synthesized by reacting the paraphenylene compound represented by r) in the presence of an oxidizing agent.

General formula [I[) (wherein, A and B have the same meanings as those described in the above general formula (1)) General formula (I[[) (wherein, R+, Rz, R3, R4, Rs and Rh
has the same meaning as described in general formula (1). ) This reaction, ie, the coupling reaction, is preferably carried out under basic conditions, and the reaction medium may be an organic solvent, an aqueous organic solvent, or an aqueous solution. Further, the oxidizing agent may be any one having a potential capable of oxidizing p-phenylenediamine, whether organic or inorganic. Examples of the oxidizing agent include silver halide, hydrogen peroxide, manganese dioxide, potassium persulfate, Inorganic oxidizing agents such as oxygen, and NB
Various organic oxidizing agents such as S, chloramine T, etc. can be used.

The dye used in the present invention is a cyan dye obtained by oxidative coupling of an imidazole coupler and p-phenylenediamine, as described above.

Synthesis examples of typical dyes used in the present invention are shown below.

Synthesis example (synthesis of imidazole dye 5) 2-benzoylamino-α-bromoacetophenone 6.38 g (0
,02o+oj was suspended in 100d of acetonitrile,
4-amidino-pyridine 4.84 g (0.04 mo
f) was added and stirred at room temperature for 3 hours. The solvent was distilled off, and the residue was extracted with ethyl acetate and treated with a silica gel column to obtain an amorphous intermediate. Yield 4.42
g (65%) Synthesis of dye Dissolve 3 g of the above intermediate in 300 d of ethyl acetate and add 10%
Add 300 ml of potassium carbonate aqueous solution, stir at room temperature, and add 4-amino-3-methyl-N~ethyl-N-(β
-methanesulfonamidoethyl)aniline sulfate log
added. Next, 70% of a 10% red blood salt aqueous solution was added dropwise over 2 hours. After completion of the dropwise addition, the mixture was allowed to react at room temperature for 2 hours. After discarding the aqueous layer and washing with water twice, the solvent was distilled off. Purification was performed using a silica gel column (developing solvent: ethyl acetate:hexane = 1:3) to obtain an amorphous solid. Yield 4g (75%)
NMR.

The structure was confirmed using FD-Mass.

The imidazole dyes used in the present invention are not only extremely useful as dyes for optical recording, but also have other uses, such as filter dyes for solid-state camera tubes and color LCD televisions (e.g., mixed with yellow or magenta dyes). It can also be used as a yellow or blue filter.

The optical recording material of the present invention basically consists of a substrate and a recording layer containing an imidazole dye, but if necessary, an undercoat layer is further provided on the substrate and a protective layer is provided on the recording layer. layers can be provided.

The substrate in the present invention may be either transparent or opaque to the laser beam used.

Substrate materials include glass, plastic, paper,
Supports of general recording materials such as plate-shaped or foil-shaped metals may be used, but plastics are preferable from various points of view.

Examples of the plastic include acrylic resin, methacrylic resin, vinyl acetate resin, vinyl chloride resin, nitrocellulose, polyethylene resin, polypropylene resin, polycarbonate resin, polyimide resin, epoxy resin, polysulfone resin, and the like.

When imidazole dye is used as the information recording layer in the optical recording material of the present invention, the film thickness is 100 μm to 5 μm.
, preferably 1000 to 3. It is p m. The film can be formed by a commonly used thin film forming method such as a vacuum evaporation method, a sputtering method, a doctor blade method, a casting method, a spinner method, or a dipping method. Moreover, a binder can also be used if necessary. As a binder, PVA, PVP, nitrocellulose,
Known dyes such as cellulose acetate, polyvinyl butyral, and polycarbonate are used, and the amount of imidazole dye to resin is preferably 6.01 or more by weight. In the case of film formation by spinner method, the rotation speed is 500~
The speed is preferably 5000 rpm, and after the spin code, treatment such as heating or exposure to solvent vapor may be performed as the case requires.

In order to improve the stability and light resistance of recording materials, transition metal chelate compounds (e.g., acetylacetonate chelate, bisphenyldithiol, salicylaldehyde oxime, bisdithio-
(alpha-diketone, etc.), and further, other dyes may be used in combination as necessary. The other dyes may be other types of imidazole dyes, or other types of dyes such as triarylmethane dyes, azo dyes, cyanine dyes, and squalirium dyes.

When forming a recording layer by a coating method such as a doctor blade method, a cast method, a spinner method, or a dipping method, in particular, a spinner method, the coating solvent may be tetrachloroethane, bromoform, dibromoethane, ethyl cellosolve, xylene, chlorobenzene, or cyclohexanone. etc. boiling point 120
~160°C is preferably used.

The recording layer of the optical recording material of the present invention may be provided on both sides of the substrate or only on one side.

Recording on the optical recording material obtained as described above is carried out by irradiating the recording layer provided on both sides or one side of the substrate with laser light, preferably semiconductor laser light, focused to about 1 μm. The area irradiated with the laser light will undergo decomposition, evaporation, and
Thermal deformation of the recording layer, such as melting and sublimation, occurs.

The recorded information is reproduced by using laser light to read the difference in reflectance between areas where thermal deformation has occurred and areas where thermal deformation has not occurred.

Laser beams used for the optical recording material of the present invention include N, , He-Cd, Ar, He-Ne, ruby, semiconductor, and dye lasers, but are especially lightweight, easy to handle, and compact. Semiconductor lasers are preferred from the viewpoint of performance and the like.

EXAMPLES Next, the present invention will be explained in more detail using Examples, but the present invention is not limited to these Examples.

Example 1 After dissolving the imidazole dye (5) Ig synthesized as described above used in the present invention in 50 g of dibromoethane,
A dye solution was obtained by filtration using a 0.22μ filter.

A PMMA resin substrate (5 inches) made of ultraviolet curing resin with a groove of 700 mm deep and 0.7 μ wide was used as the substrate for the optical disk, and 2 m of the dye solution was placed on this substrate.
1 was added dropwise using a spinner method and applied at a rotation speed of 120 Orpm+. After coating, it was dried at 60°C for 10 minutes.

In order to measure this film thickness, the film thickness was measured by α-step using a glass plate under the same conditions, and the film thickness was found to be 3,700. Moreover, the maximum absorption wavelength of this coating film was 640 nm.

As a result of writing on the thus obtained optical disk using a He-Ne laser with a beam diameter of 2.4 um and a wavelength of 632.8 nm as a light source, pits (holes) with a uniform and clear shape were obtained. . The C/N ratio and storage stability were also good.

Example 2 Instead of dye (5) used in Example 1, equimolar amount of dye (
16), (20), (22), and (25), an optical disc was manufactured according to the method described in Example 1. The coating film thickness and maximum absorption wavelength of the obtained optical disc are shown in the table.

Among these, the absorption spectrum of dye (22) used in the present invention is shown in FIG.

Since it has high solubility in surface solvents, it can be coated by coating, and optical recording materials obtained using this dye have high reflectance, good contrast, and excellent storage stability. , is extremely useful.

A HeNe beam with a beam diameter of 2.4 pm and a wavelength of 632.8 nm and 632.8 m was used as a light source for the optical disc thus obtained.
When writing was performed using a laser, pits (holes) with a uniform and clear shape were obtained.

Furthermore, the C/N ratio was good, and the storage stability was also good. The effects of the present invention were also obtained when a semiconductor laser was used as the light source instead of the He-Ne laser.

Effects of the Invention The imidazole dye used in the present invention is manufactured by Ganto Arita.
Konica Co., Ltd. Agent Patent Attorney Miki Nakajima Yugai 1 Master Itouri Neho Seisho (Form) December 15, 1988

Claims (1)

[Claims] 1) An optical recording material containing an imidazole dye represented by the general formula [I]. General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. It may also form a membered ring. R_3, R_4, R_5 and R_6 each represent a hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl group, an alkoxy group, a substituted alkoxy group, an amino group or a substituted amino group. A and B represent an organic group bonded to the imidazole ring via a carbon atom, nitrogen atom, oxygen atom or sulfur atom. 2) In an optical recording material including a recording layer and a substrate, in which recording is performed by changing the state with a laser beam, the recording layer contains an imidazole dye represented by the general formula [I]. Optical recording material according to claim 1, characterized in: